Plastic and Reconstructive Surgery Board Review Pearls of Wisdom 3th

817
Todd A. Theman, MD and
Matthew L. Iorio, MD

What are the boundaries o the emoral triangle?
• Proximally—inguinal ligament.
• Laterally—sartorius.
• Medially—adductor longus.
• Floor—iliacus, psoas, pectineus, and adductor longus.

Which muscles o the lower extremity are located in the super cial posterior compartment? What is the
innervation and unction o each? Super cial posterior compartment?
• Gastrocnemius, innervated by posterior tibial nerve, unctions in plantar exion.
• Plantaris (as or gastrocnemius).
• Soleus (as or gastrocnemius).

Deep posterior compartment?
• Flexor hallucis longus/posterior tibial nerve/toe exion.
• ibialis posterior/posterior tibial nerve/inversion and plantar exion o ankle.
• Flexor digitorum longus (as or exor hallucis longus).

Lateral compartment?
• Peroneus brevis/super cial peroneal nerve/ankle eversion.
• Peroneus longus (as or brevis).
Lower Extremity
Reconstruction—
Soft-Tissue Concepts
CHAPTER 86

818
Plastic & Reconstructive Surgery Board Review

Anterior compartment?
• ibialis anterior/deep peroneal nerve/ankle dorsi exion.
• Extensor digitorum longus/deep peroneal nerve/toe extension.
• Extensor hallucis longus/deep peroneal nerve/toe extension.
• Peroneus tertius/deep peroneal nerve/ankle eversion and weak dorsi exion.

In which compartments do the tri urcated arteries travel in the lower extremity?
Anterior tibial artery—anterior compartment.
Posterior tibial artery—deep posterior compartment.
Peroneal artery—deep posterior compartment.

What nerve may accompany the lesser saphenous vein and what does it innervate?
T e sural nerve provides sensation to the skin over the posterolateral lower extremity, the lateral heel, and the lateral
border o the oot. It is ound between the Achilles tendon and lateral malleolus and up to 25 cm can be harvested.

T e plantar sur ace o the oot may be divided into our layers. Which muscles may be ound in the most
super cial layer?
• Flexor digitorum brevis.
• Abductor hallucis.
• Abductor digiti quinti.

What nerves provide sensation to the oot and what are their respective dermatomes?
• Posterior tibial nerve—plantar mid oot and heel
• Sural nerve—lateral mid oot
• Saphenous nerve—medial ankle
• Super cial peroneal nerve—dorsal distal oot
• Deep peroneal nerve— rst web space

Which tendon o the lower extremity is the pre erred donor or gra ting and which nerve is most at risk
during harvest?
Plantaris tendon. It is present in approximately 80% o lower limbs. Dissection begins just posterior to the medial
malleolus, placing the posterior tibial nerve at risk.

What ndings are indicative o compartment syndrome?
• Palpable rmness o compartment, pallor, pain on passive extension is compartment-speci c:
• Anterior: pain on passive plantar exion and oot eversion, toe exion.
• Lateral: pain on passive dorsi exion and oot inversion.
• Super cial posterior: pain on passive ankle dorsi exion with knee extended.
• Deep posterior: pain on passive ankle dorsi exion, toe extension.
• Compartmental pressures > 35 mm Hg (or dif erential pressure < 30)
• Pulselessness is a very late nding as venous and lymphatic ow through the compartment will occlude prior
to compression o arterial ow. A dif erential pressure is obtained by subtracting the compartmental pressure
rom the patient’s diastolic pressure.

CHAPTER 86 Lower Extremity Reconstruction—So t- issue Concepts
819

How do you treat a compartment syndrome o the lower extremity?
Fasciotomies. Medial and lateral longitudinal incisions should allow adequate exposure to incise intermuscular
septae, thereby releasing all our compartments. Remember that asciotomies will also be appropriate or expected
severe elevation in compartment pressures that are associated with crush injury, electrical burn, massive uid
resuscitation, and reper usion injury.

What is the procedure o choice or reconstruction o small-to-medium de ects o the plantar sur ace o the
oot?
V-Y plantar advancement ap. T e plantar skin and ascia should be incised congruently to maintain intact the
vessels per orating the ascia rom the medial and lateral plantar arteries.

What would you do to reconstruct a more extensive de ect o the plantar oot in an ambulatory patient?
Provide so t-tissue coverage that is durable and tolerant o shear orces experienced with ambulation. A muscle ap
with a skin gra t has been shown to per orm well or such reconstructions.

What additional measures should be considered when reconstructing the plantar sur ace o the oot?
I the plantar sur ace is insensate, the patient should be educated on being vigilant and meticulous in caring
or the oot. Custom orthotics with a metatarsal bar should decrease metatarsal head pressure and shearing and
compression orces on the reconstructed oot.

What is the Gustilo classi cation system or tibial injury?
Gustilo classi cation

What is the Byrd classi cation system or tibial injury?
Byrd classi cation.
I
Low-energy, simple bone fracture, clean wound < 1 cm.
II
Moderate comminution and contamination, wound > 1 cm, moderate soft-tissue damage.
III
A
B
C
High energy, comminution of the fracture, wound > 1 cm, extensive soft-tissue damage, highly
contaminated.
Adequate soft-tissue cover.
Inadequate soft-tissue coverage, extensive periosteal stripping.
Arterial injury requiring repair for salvage.
I
Low-energy fracture, oblique or spiral fracture with clean-cut laceration < 1 cm.
II
Medium-energy trauma, displaced or comminuted fracture with laceration > 2 cm,
myocutaneous contusion.
III
High-energy trauma, severely displaced or comminuted fracture, segmental fracture or bone
defect, laceration > 2 cm, myocutaneous soft-tissue loss.
IV
High-energy bursting trauma, crushing or avulsion with arterial damage (that requires repair).

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Plastic & Reconstructive Surgery Board Review

What muscles can be used to reconstruct the so t tissue over the proximal one-third o the tibia?
Medial gastrocnemius (medial sural artery and venae comitantes). T e medial hemi-gastrocnemius is the larger
and longer o the two and is more commonly used.
Lateral gastrocnemius (lateral sural artery and venae comitantes).

What muscle can be used to reconstruct the so t tissue over the middle one-third o the tibia?
Soleus (the proximal muscle is supplied by branches o the peroneal artery while the distal muscle is supplied by
posterior tibial artery per orators). Modi cations o this muscle may be made, such as a hemisoleus or greater arc
o rotation. A split tibialis anterior muscle ap may also be used or long, thin de ects.

What f aps can be used to reconstruct the so t tissue over the distal one-third o the tibia?
Free muscle or asciocutaneous aps. T e choice o ap will depend upon the extent o so t-tissue injury, necessary
pedicle length, and the surgeon’s amiliarity. While a ree tissue trans er or a distal one-third open tibial racture is
the classic answer, there are possibilities o local aps, such as a distally based hemisoleus ap or propeller ap.

T e anterolateral thigh (AL ) f ap has become a workhorse o lower extremity so t-tissue reconstruction. What
landmarks are used to mark the f ap, what is the pedicle, and what muscle is sometimes harvested with the f ap?
T e meridian o an AL ap is along a line drawn rom the ASIS to the superolateral border o the patella with the
hip internally rotated. T e descending branch o the lateral circum ex emoral artery (branch o pro unda emoris)
is the pedicle. T e per orators may traverse the vastus lateralis muscle, which can be harvested also. Mark the
midpoint o this line and per orators are usually ound 5 cm proximal and distal to this midpoint and 1 to
2 cm medial to the line.

Within what time rame should an osteocutaneous de ect o the tibia receive de nitive so t-tissue
reconstruction?
Ideally within 72 hours, a ter which the total complication, rate including in ections and ap loss, increases
dramatically. Inadequate so t-tissue or bone debridement is the common cause o postoperative ailure, and while
early so t-tissue coverage is important, it should not be at the expense o adequate debridement.

A reverse-f ow sural artery f ap is used to reconstruct a calcaneus wound. o best preserve the vascularity o
this f ap, the distal dissection o the pedicle should terminate where?
5 cm above the lateral malleolus, in order to not divide peroneal artery per orators that supply the ap. Partial ap
loss is the most common complication.

What actors avor amputation over lower extremity salvage/reconstruction?
• Insensate plantar sur ace o oot (particularly in adults with a nerve gap).
• Ischemia time > 6 hours or crush mechanism.
• Multi-level injury in the ipsilateral limb.
• Loss o plantar exion.
• Severe comorbid illness or condition precluding reconstruction.
T e literature remains divided on whether reconstruction or amputation is associated with better long-term
unctional outcomes, return to work, and cost, so treatment decisions remain individualized. Absent plantar
sensation does not preclude reconstruction, as approximately 50% o patients with an intact nerve will regain
plantar sensation at 2 years. While a low initial injury severity score is associated with salvage, a high score does
not predict amputation and is not associated with long-term unctional outcomes.

CHAPTER 86 Lower Extremity Reconstruction—So t- issue Concepts
821

You are asked to emergently evaluate a newborn with a threatened lower limb. You nd a congenital
constriction ring with severe distal lymphedema, progressive cyanosis, and club oot. What is the next step in
management?
Congenital constriction bands present along a spectrum rom shallow so t-tissue depression to constriction
ring with distal lymphedema and acrosyndactyly ( usion o distal parts), progressive lymphatic or arteriovenous
compromise, and congenital amputation. T ey are requently associated with prematurity, low birth weight,
and club oot. Limb-length discrepancies are common in in ancy. T e rare case o a deep constriction ring with
progressive neurologic arteriovenous compromise necessitates emergency limb salvage. T e etiology is early
amnion rupture and oligohydramnios.
Correction o the de ormity involves excision o the constriction ring, reconstruction o underlying absent
structures (tendon, nerve), correction o limb length discrepancy with lengthening or contralateral epiphysiodesis,
and adipo ascial aps and/or local transposition aps to ll the contour de ormity.
REFERENCES
Askins G, Ger E. Congenital constriction band syndrome. J Pediatr Orthop. 1988;8:461–466.
Francel J, Vander Kolk CA, Hoopes JE, Manson PN, Yaremchuk MJ. Microvascular so t-tissue transplantation or reconstruction o
acute open tibial ractures: timing o coverage and long-term unctional results. Plast Reconstr Surg. 1992;89:478–487; discussion
488–489.
Godina M. Early microsurgical reconstruction o complex trauma o the extremities. Plast Reconstr Surg. 1986;78(3):285–292.
Gustilo RB, Mendoza RM, Williams DN. Problems in the management o type III (severe) open ractures: a new classi cation o type
III open ractures. J Trauma. 1984;24:742–746.
Hasegawa M, orii S, Katoh H, Esaki S. T e distally based super cial sural artery ap. Plast Reconstr Surg. 1994;93:1012–1020.
Kasabian AK, Karp NS. Lower extremity reconstruction. In: Aston SJ, Beasley RW, T orne CH, eds. Grabb and Smith’s Plastic Surgery.
5th ed. Philadelphia, PA: Lippincott-Raven; 1997:1031–1048.
May JW Jr, Rohrich RJ. Foot reconstruction using ree microvascular muscle aps with skin gra ts. Clin Plast Surg. 1986;13:681–689.
T orne CH, Siebert JW, Grotting JC, et al. Reconstructive surgery o the lower extremity. In: McCarthy JG, ed. Plastic Surgery.
Philadelphia, PA: WB Saunders; 1990:4029–4092.
Warren AG, Brorson H, Borud LJ, Slavin SA. Lymphedema: a comprehensive review. Ann Plast Surg. 2007;59:464–472.

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823
Pieter G.L. Koolen, MD,
John B. Hijjawi, MD, FACS, and
Samuel J. Lin, MD, MBA, FACS

How many compartments exist in the thigh and leg? Which muscles, nerves, and blood vessels lie in which
compartments?
T igh ( able 87-1)
Lower Extremity
Reconstruction—
Orthopedic Concepts
CHAPTER 87
Com partm ent

Motor Nerve

Blood Supply

Muscles
Anterior

Femoral (L2-4)

Femoral

Q uadriceps emoris, sartorius
iliopsoas, pectineus
Medial

Obturator (L2-4)

Pro unda emoris
Obturator
Gracilis, adductor longus
A dductor brevis, adductor magnus,
Obturator externus
Posterior

Sciatic (L4-S3)

Pro unda emoris
(branches)
Biceps emoris, semitendinosus
Semimembranosus
Adductor magnus
able 87-1

824
Plastic & Reconstructive Surgery Board Review
Lower Leg ( able 87-2)
Com partm ent

Motor Nerve

Blood Supply

Muscles
Anterior

Deep peroneal

Tibialis anterior

Tibialis anterior
Extensor digitorum longus
Extensor hallucis longus
Peroneus tertius
Lateral

Superf cial peroneal Peroneal

Peroneus longus
Peroneus brevis
Superf cial posterior Tibialis (branches)

Tibialis posterior (branches) Gastrocnemius
Plantaris
Soleus
Deep posterior

Tibialis

Tibialis posterior

Popliteus
Flexor digitorum longus
Flexor hallucis longus
Tibialis posterior
able 87-2

Which nerves supply sensation to the oot?
• Dorsum: super cial peroneal except the rst web which is supplied by the deep peroneal.
• Sole: medial and lateral plantar rom the posterior tibial.

What are the biomechanical e ects o the oot that make reconstruction potentially suboptimal?
Normal gait requires the oot to transition rom a exible structure to a rigid structure as the hind oot makes
contact and orces are transitioned to the ore oot. T e ore oot’s unique osteoligamentous structures acilitate this
conservation o energy. Current ap techniques cannot replicate the biomechanics o the intact oot.

What percentage o patients with diabetes mellitus develops heel ulcers?
15%.

What are the possible biomechanical e ects on the oot o patients with diabetes mellitus?
• Reduced subtalar joint mobility.
• Limited rst metatarsal mobility.

What is a Charcot oot?
It is acute or gradual arthropathy o the oot that most commonly occurs in patients with diabetes. It was
originally described in patients with syphilis. T e pathophysiology o the disease has not been de nitively
elucidated but it may involve trivial microtrauma that a ects the joints o the oot. Another theory attributes
autonomic changes that lead to increased osteopenia o the bones. Swelling, erythema, pain, and ulceration (40%)
may develop that mimics in ection. Collapse o the osseoligamentous structures o the oot leads to derangements
in pressure points on the oot.

CHAPTER 87 Lower Extremity Reconstruction—Orthopedic Concepts
825

What is the most common location o bony sarcomas o the lower extremity?
Proximal tibia.

What are the most common complications o limb salvage or these sarcomas?
• Wound healing (skin ap necrosis).
• Wound in ection.
• Nerve palsy.
• Hardware ailure.

What are the treatment options o resectable bony sarcomas o the distal emur and proximal tibia?
• Amputation.
• Reconstruction with oncologic appliance and so t-tissue ap.
• Rotationplasty (children).

Why is it necessary to per orm ap coverage o the knee oncologic appliance or tumors o the distal emur/
proximal tibia?
Wound complication rates o over 50% have been reported with prosthesis placement without ap coverage.
Malignant lesions in this region require resection o adjacent so t tissue, skeletonization o neurovascular
structures, and development o large subcutaneous aps. T is leads to an increased risk o implant exposure and
in ection without the use o adjunctive ap coverage.

What is a Girdlestone procedure?
Described in the 1940s, it is resection o the emoral head and neck or severe in ection o the hip. Although the
procedure is uncommon in the modern era, it is still employed or severe stage IV trochanteric pressure ulcers
complicated by osteomyelitis. T e vastus lateralis muscle ap may be employed to interpose in the dead space
created by the resection.

What are the ambulatory implications o a Girdlestone procedure?
T e leg will be shorter and require the patient to be dependent on walking aids, such as a walker or crutch.

What are the possible clinical circumstances o a peroneal nerve injury?
• Fracture o a tibia or bula.
• Sharp injury.
• Severe adduction injury o the knee.
• Gunshot wound.
• Iatrogenic (ganglion resection, bula harvest).

Why should tourniquet placement directly below the knee (proximal leg) be avoided?
Peroneal nerve palsy with compression at the head o the bula may develop. Place the tourniquet above the knee.
Avoid tourniquets in patients with vascular bypass gra ts across the region o tourniquet control.

826
Plastic & Reconstructive Surgery Board Review

I the common peroneal nerve is disrupted, what are the treatment options?
• Primary repair o nerve in the low-energy or sharp injury with or without nerve gra t. T is can be per ormed
immediately or within weeks a ter the injury.
• ibialis posterior trans er. Since an equinovarus de ormity inevitably develops despite use o a kick-up brace,
muscle balancing with early tendon trans er may be advantageous.

What is Gustilo’s classif cation o open tibial ractures as modif ed in 1998?
• I: “with cutaneous de ect < 1 cm, clean, little so t-tissue injury”
• II: “laceration > 1 cm, no extensive so t-tissue injury, no aps or avulsions” moderate crush injury and
comminution o bone and contamination.
• III: extensive so t-tissue damage with muscle and sometimes n/vasc, high contamination “included are high-
energy, industrial, segmental, and severe comminution.”
• IIIA: “extensive so t-tissue lacerations, high-energy injury but cover available.”
• IIIB: “so t-tissue loss and periosteal stripping, massive contamination, bone comminution or loss.”
• IIIC: any injury with arterial injury requiring repair regardless o so t-tissue damage degree.

In general, which injuries in the Gustilo’s classif cation require so t-tissue aps?
Gustilo IIIB and IIIC injuries usually require ap coverage.

A ter a limb-threatening lower extremity injury (Gustilo type IIIB), is the unctional outcome better a ter
limb salvage or early amputation?
T ey have equivalent unctional outcomes at 2 and 7 years a ter the injury.

For Gustilo IIIB ractures o the tibial sha t, what is the recommended orm o f xation?
Intramedullary nailing is the treatment o choice or most o these injuries. T ere is controversy whether the nail
should be placed with or without intramedullary reaming. External xation may be used initially, especially in
patients presenting with highly contaminated wounds.

What is the amputation rate or Gustilo grade IIIC tibial racture?
87%.

T e classif cation using the mangled extremity severity score (MESS, Johansen 1990) classif es patients
according to which o the our criteria?
• Shock.
• Ischemia.
• Age.
• Skeletal/so t-tissue damage.

Do limb injury severity scores such as the MESS correlate with unction a ter limb salvage?
No. When prospectively evaluated, a low score has been shown to indicate a high likelihood o success ul limb
salvage; however, high scores are poorly predictive o unction and should be used cautiously.

CHAPTER 87 Lower Extremity Reconstruction—Orthopedic Concepts
827

What actors best correlate with unctional outcome a ter a limb-threatening lower-extremity injury?
Socioeconomic and demographic actors have the best correlation with eventual outcome. Factors associated
with a poorer outcome include lower education level, economic status, older age, emale gender, nonwhite race,
smoking, poor sel -ef cacy, and being involved in a lawsuit. A major complication also correlates with a poorer
outcome.

Should absent plantar sensation be used as an indication or early amputation?
No, over 50% o patients presenting with an insensate oot a ter a lower extremity injury regain plantar sensation
and eventual sensory unction is similar to other patients with severe lower extremity injuries. A visualized
disruption o the tibial nerve may be considered an indication or amputation in an adult.

What percentage o patients with a limb-threatening lower extremity injury return to employment?
58% return to employment within 7 years o the injury.

What percentage o patients with a limb-threatening lower extremity injury regain a unctional status within
population norms?
34% eventually recover an overall unctional status within the normal range or the population as measured by the
Sickness Impact Pro le.

A ter a limb-threatening lower extremity injury (Gustilo type IIIB), which treatment has a higher associated
cost: early amputation or limb salvage?
At 2 years, postinjury medical costs are similar between the two groups. While patients treated with limb salvage
have higher costs associated with rehospitalizations or acute care, those treated with amputation have higher
costs associated with rehabilitation. When considering the prosthesis-associated costs, the patients treated with
amputation have a higher overall cost at 2 years. Over the course o a li etime, it is projected that the costs
associated with an amputation are triple those o limb salvage, making reconstruction a cost-e ective treatment.

How does one assess bony viability when surgically treating a patient with osteomyelitis?
Assess or the presence o punctate bleeding rom the bone a ter debridement (the paprika sign). T is is most
commonly done using a burr and the presence o bleeding rom the bone indicates viability.

According to Godina, patients requiring ree- ap reconstruction or tibial coverage are classif ed as
reconstructed:
Early (< 72 hours), delayed (> 72 hours and < 3 months), or late (> 3 months).

Microvascular ailure and in ection was commonest in which group?
Delayed group.

Microvascular success and absence o in ection was commonest in which group?
Early group.

828
Plastic & Reconstructive Surgery Board Review

What are the reconstructive options or a large (> 5 cm) bony gap/de ect in the tibia?
T ese de ects may be treated with acute shortening and subsequent lengthening or bone transport using a ring
external xator rame (Ilizarov rame). A ree vascularized bone trans er (typically a ree bula gra t) is another
option. More recently the induced membrane technique o Masquelet has become popular as well. T is involves
placement o a temporary polymethyl methacrylate (PMMA) cement spacer with subsequent cancellous bone
gra ting.

Ilizarov distraction osteogenesis distracts approximately at what rate?
0.25 mm distraction × 4/day.

A ter the desired length o bone is achieved, how long is the Ilizarov rame le t on?
For the same length o time as the distraction to allow consolidation.

What is the ideal length that should be preserved or a below-knee amputation?
Optimally 12 to 15 cm as measured rom the knee joint line. Residual limbs that are too short are more dif cult
to t with a prosthesis and may unctionally act similar to a through knee amputation rather that a BKA. Residual
limbs that are too long may have compromised so t-tissue coverage. I the residual limbs are too long, it may also
compromise prosthesis options because some o the most advanced prosthetics are 10 inches in length and require
adequate shortening o the limb in order to be used.

What is a Lis ranc amputation?
Amputation through the level o the transmetatarsal joints.

What is a Symes amputation?
Amputation just above the ankle joint.

What are the f rst signs in compartment syndrome?
General pain and tingling in the limb out o proportion with the injury with pain on passive extension o the
involved muscle groups.

What is the normal tissue pressure?
2 to 7 mm Hg.

At what tissue pressure is one concerned o compartment syndrome?
An absolute pressure o 30 mm Hg or within 30 mm Hg o diastolic blood pressure is concerning or
compartment syndrome.

What incisions would you use to per orm asciotomies to the lower leg?
wo vertical incisions 2 cm to either side o the subcutaneous border o the tibia.

T rough which o the above incisions would you decompress the posterior compartments?
Usually the medial one.

CHAPTER 87 Lower Extremity Reconstruction—Orthopedic Concepts
829

Which compartments are released via the lateral incision?
Anterior and lateral compartments.

What is the commonest organism associated with acute osteomyelitis?
Staphylococcus aureus.

In children which organism is commonly associated with acute osteomyelitis other than S. aureus?
Haemophilus inf uenzae. However, the incidence o this has decreased in recent years with the vaccination o
children or H. inf uenzae.
REFERENCES
Bosse MJ, MacKenzie EJ, Kellam J, et al. An analysis o outcomes o reconstruction or amputation o leg-threatening injuries. N Engl
J Med. 2002;347:1924–1931.
Bosse MJ, MacKenzie EJ, Kellam JF, et al. A prospective evaluation o the clinical utility o lower extremity injury-severity scores. J Bone
Joint Surg Am. 2001;83:3–14.
Bosse MJ, McCarthy ML, Jones AL, et al. T e Lower Extremity Assessment Project (LEAP) stud. T e insensate oot ollowing severe
lower extremity trauma: an indication or amputation? J Bone Joint Surg Am. 2005;87:2601–2608.
Ferraresi S, Garozzo D, Bu atti P. Common peroneal nerve injuries results with one-stage nerve repair and tendon trans er. Neurosurg
Rev. 2003;26:175–179.
Hijjawi JB, Dumanian GA. T e diabetic and ischemic lower extremity. In: McCarthy JG, Galiano RD, Boutros S, eds. Current T erapy
in Plastic Surgery. 1st ed. Philadelphia, PA: Elsevier Science-Saunders; 2006.
Lindner NJ, Ramm O, Hillmann A, et al. Limb salvage and outcome o osteosarcoma. T e University o Muenster experience. Clin
Orthop Relat Res. 1999;(358):83–89.
MacKenzie EJ, Bosse MJ, Pollak AN, et al. Long-term persistence o disability ollowing severe lower-limb trauma. results o a seven-year
ollow-up. J Bone Joint Surg Am. 2005;87:1801–1809.
MacKenzie EJ, Jones AS, Bosse MJ, et al. Health-care costs associated with amputation or reconstruction o a limb-threatening injury?.
J Bone Joint Surg Am. 2007;89(8):1685–1692.
Millesi H. Brachial plexus injuries: management and results. In: erzis JK, ed. Microreconstruction o Nerve Injuries. Philadelphia, PA:
WB Saunders; 1987:243–249.
Rao S, Saltzman C, Yack HJ. Segmental oot mobility in individuals with and without diabetes and neuropathy. Clin Biomech (Bristol,
Avon). 2007;22:464–471.
Schroeder J, Saris D, Besselaar PP, Marti RK. Comparison o the results o the Girdlestone pseudarthrosis with reimplantation o a total
hip replacement. Int Orthop. 1998;22:215–218.

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831
Ryan Stehr, MD and
Robert J. Havlik, MD

What is the etiology o pressure sores?
Pressure sores arise as a result o tissue ischemia developing rom pressure over a bony prominence. Pressure
between the sur ace the patient rests on and the underlying bone may approach or exceed the patient’s blood
pressure, leading to tissue ischemia and/or tissue death.

What are the risk actors o pressure sore development?
Increased age, spinal cord injury, spasticity, decreased skin sensation, paraplegia, quadriplegia, prolonged
immobilization, bowel or bladder incontinence. Malnutrition is not proven to be a risk actor.

Where are the most common sites o pressure sores?
T e most common site is overlying the ischial tuberosity, ollowed by the trochanters or the sacrum.

What are the stages o pressure sores?
Revised in 2007, the National Pressure Ulcer Advisory Panel stages are the ollowing:
Suspected deep tissue injury: Areas o purple or maroon discoloration with intact skin or blistering in the setting o
excessive pressure and shear.
Stage I: Intact skin with nonblanching erythema, usually over a bony prominence.
Stage II: Partial-thickness loss o dermis.
Stage III: Full-thickness skin loss with visible subcutaneous at, which may extend down to the deep ascia. T ere
may be slough in the wound and undermining or tunneling.
Stage IV: Full-thickness tissue loss beyond the deep ascia with exposed bone, tendon, or muscle.
Unstageable: Excessive slough or eschar prevents accurate assessment o wound depth.
Pressure Sores
CHAPTER 88

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Plastic & Reconstructive Surgery Board Review

What are some basic principles guiding pressure sore treatment and reconstruction?
All contributing actors to the etiology o the pressure sore should rst be addressed. For example, incontinence
must be controlled or else any interventions will inevitably ail. A recent illness in the patient or loss o amily
support may even be contributing actors.
Stages I and II—T ese wounds are considered reversible, and with proper local wound care, adequate nutritional
support and pressure o -loading adjuncts, they o ten heal without surgical intervention.
Stages III and IV—Usually require surgical intervention in addition to pressure o -loading adjuncts. All nonviable
tissue should be debrided and then so t-tissue coverage should be undertaken. In the paraplegic population,
spasticity should be addressed as this can cause ap breakdown by making pressure problems worse or causing
shearing.

What in ections are commonly associated with pressure sores?
Urinary tract in ections and pneumonia. For the majority o patients with spinal cord injury and pressure sores
who present with a ever, the source will be the urinary tract or the lungs. Fever is much less commonly caused by
the pressure sore, as this is usually a clean, contaminated wound that is adequately draining.

What laboratory tests are use ul in the diagnosis o osteomyelitis in a pressure sore?
A white blood cell count will o ten be elevated in osteomyelitis; however, it is nonspeci c. An elevated erythrocyte
sedimentation rate > 120 mm/hr is much more speci c or osteomyelitis.

What radiologic test is most help ul in the diagnosis o osteomyelitis in a pressure sore?
Un ortunately, there is no single radiologic test that remains the gold standard. Some authors advocate MRI, C
scan, or bone scans; however, plain lm o the pelvis appears to have equivalent sensitivity.

What is the gold-standard test to conf rm osteomyelitis in a pressure sore?
While laboratory and radiologic tests are o ten used to aid in the diagnosis o osteomyelitis, de nitive diagnosis is
obtained at the time o surgery with a sterile, open bone biopsy and culture to guide antibiotic therapy. Antibiotics
should be held until cultures are obtained, i possible.

What are the more common bacteria associated with pressure sores?
Staphylococcus aureus, Proteus mirabilis, Pseudomonas aeruginosa, and Bacteroides fragilis are commonly isolated;
however, the cultures are usually polymicrobial.

What is appropriate treatment or osteomyelitis in pressure sores?
Six to eight weeks o intravenous antibiotic therapy guided by antimicrobial susceptibility results rom a sterile,
open bone biopsy.
wo schools o thought exist on the timing o reconstruction. One recommends immediate reconstruction at the
time o excision ollowed by IV antibiotics, while the other recommends negative pressure wound therapy until IV
antibiotics are completed ollowed by delayed closure.

What is the etiology o spasticity in paraplegics?
Elimination o higher CNS suppression o spinal re ex arcs leading to hypertonia and hyperre exia.

CHAPTER 88 Pressure Sores
833

What is the signif cance o spasticity in pressure sore management?
It can exacerbate pressure points, place tension on wound edges, and contribute to joint or muscle contracture.

What are some treatments or spasticity?
Systemic diazepam or baclo en, intrathecal baclo en pump, phenol or alcohol, neurosurgical treatment with
cordotomy or rhizotomy.

What are the reconstructive options or sacral pressure sores?
1. Gluteus maximus musculocutaneous ap.
2. Gluteal asciocutaneous rotation ap.
3. Superior gluteal artery per orator ap.

What are the reconstructive options or ischial pressure sores?
1. Gluteus maximus musculocutaneous ap.
2. In erior gluteal thigh asciocutaneous ap.
3. V-Y hamstring asciocutaneous ap with or without biceps emoris muscle.

What are the reconstructive options or trochanteric pressure sores?
1. ensor ascia lata ap.
2. T igh rotational ap.
3. In erior gluteal thigh ap.

What is a Girdlestone arthroplasty and when is it indicated?
Girdlestone arthroplasty involves resection o the emoral head and a portion o the proximal emur. T is is usually
per ormed to treat septic arthritis o the hip joint. T e acetabulum should also be debrided. In order to obliterate
the dead space between the acetabulum and the emoral sha t, the vastus lateralis muscle ap may be used.

Why do patients with spinal cord injury and denervated tissues experience poor wound healing?
T e exact etiology o delayed wound healing in patients with denervated tissues is not completely elucidated;
however, current research indicates that nerve growth actor (NGF) and substance P (SP) play an important
role in normal wound healing. NGF is produced by target tissues such as the skin and subcutaneous tissue and
undergoes retrograde transport by sensory nerve bers. NGF regulates the release o substance P, which then acts
as a chemoattractant or neutrophils and macrophages. Additionally, substance P acts as a vasodilator and regulates
a number o other in ammatory mediators produced by leukocytes. Patients with spinal cord injuries or other
causes o denervated tissue have been shown to have decreased levels o substance P in their wounds. Rat models
have shown improved wound healing with administration o exogenous substance P.

What surgical tactics can be used to potentially decrease pressure sore recurrence?
In selected patients with a low spinal cord injury, use o a sensate ap can be used to restore protective sensation to
the injured area. T is can be done or sacral sores by using tissue expansion in the lower pack. No strong evidence
exists to show that this technique reduces recurrence.

834
Plastic & Reconstructive Surgery Board Review

What nonsurgical tactics can be used to prevent uture pressure sores?
Minimize pressure over bony prominences and reconstructions by requent turning and pressure relieving
mattresses, proper hygiene, control o incontinence, aggressive management o spasticity and contracture.
REFERENCES
Barker AR, Rosson GD, Dellon AL. “Wound healing in denervated tissue.” Ann Plast Surg. 2006;57(3)339–342.
Bauer J, Phillips LG. MOC-PSSM CME article: pressure sores. Plast Reconstr Surg. 2008;121(1 suppl):1–10.
Braden BJ, Bergstrom N. Clinical utility o the Braden scale or predicting pressure sore risk. Decubitus. 1989;2(3):44–46, 50–51.
Di Caprio G, Serra-Mestre JM, Ziccardi P, et al. Expanded aps in surgical treatment o pressure sores: our experience or 25 years. Ann
Plast Surg. 2014;75:552–555.
Evans GR, Lewis VL Jr, Manson PN, Loomis M, Vander Kolk CA. Hip joint communication with pressure sore: the re ractory wound
and the role o girdlestone arthroplasty. Plast Reconstr Surg. 1993;91(2):288–294.
Larson DL, Gilstrap J, Carrera GF. Is there a reliable and cost ef cient way to diagnose osteomyelitis in the pressure sore patient?.
Presented at AAPS Meeting. 2010.
Levi B, Rees R. Diagnosis and management o pressure ulcers. Clin Plast Surg. 2007;34:735–748.
Lewis VL Jr, Bailey MH, Pulawski G, Kind G, Bashioum RW, Hendrix RW. T e diagnosis o osteomyelitis in patients with pressure
sores. Plast Reconstr Surg. 1988;81(2):229–232.
National Pressure Ulcer Advisory Panel. Retrieved December 18, 2009, rom
Neves RI, Kahler SH, Banducci DR, Manders EK. issue expansion o sensate skin or pressure sores. Ann Plast Surg. 1992;29(5):
433–437.

835
Nicholas Kim, MD and
Loren S. Schechter, MD, FACS

What is gender identity?
One’s basic sense o sel as a man or woman.

What is gender dysphoria?
A term introduced by Fisk in 1973, gender dysphoria re ers to distress resulting rom con icting gender identity
and sex o assignment. It has replaced the term Gender Identity Disorder in the Diagnostic and Statistical Manual
o Mental Disorders-5th edition (DSM-5), which was implemented in 2014. T is revision o the DSM-4’s
Gender Identity Disorder was intended to avoid the stigmatizing e ect o the previous diagnostic term without
jeopardizing access to e ective treatment options.

What are the diagnostic criteria or gender dysphoria according to the DSM-5?
T ere must be marked di erence between the individual’s expressed gender and the gender others would assign
him or her. T is must continue or at least 6 months. T e critical element is the presence o clinically signif cant
impairment in social, occupational, or other important areas o unctioning.

What is transsexualism?
A term coined by Magnus Hirschf eld in 1923, a transsexual is an individual who desires to live permanently in
the social role o the opposite gender, and wants to undergo sex reassignment. In 1994, the DSM-4 committee
replaced the diagnostic term ranssexualism with Gender Identity Disorder, which has since been replaced by
Gender Dysphoria. T e International Classif cation o Diseases-10 (ICD-10) continues to use ranssexualism as a
diagnostic term under the heading o Gender Identity Disorders.

What are the diagnostic criteria or transsexualism according to the ICD-10?
T ere are three criteria: (1) the desire to live and be accepted as a member o the opposite sex; (2) the transsexual
identity has been present persistently or at least 2 years; and (3) the disorder is not a symptom or another mental
disorder or a chromosomal abnormality.
Gender Conf rmation
Surgery
CHAPTER 89

836
Plastic & Reconstructive Surgery Board Review

What is the prevalence o gender dysphoria?
T e DSM-5 reports a range rom 1 in 20,000 up to 1 in 10,000 biological men and a range rom 1 in 50,000 up
to 1 in 30,000 biological women.

Is gender dysphoria a disorder o sex development (DSD)?
No, DSD is a distinct entity representing congenital conditions in which development o chromosomal, gonadal,
or anatomic sex is atypical.

What are the Standards o Care or the Health o Transsexual?
Previously known as the Harry Benjamin International Gender Dysphoria Association Guidelines or Diagnosis
and reatment, the Standards o Care is a publication o the World Pro essional Association or ransgender
Health (WPA H). It is intended to provide exible clinical guidelines to meet the diverse health care needs o
individuals with gender dysphoria. T e most current set, Version 7, was published in 2011.

What are the mechanisms o eminization through hormone therapy?
Feminization is achieved by two mechanisms: androgen suppression using medications such as spironolactone or
f nasteride, and induction o emale characteristics using estrogen.

What are the e ects o eminization hormone therapy?
Within the f rst 6 months there is redistribution o at, decreased muscle mass, so tening o the skin, and decreased
libido. Breast growth may be expected a ter 3 to 6 months o therapy and may continue or over 2 years.

What are the e ects o masculinization hormone therapy?
estosterone therapy results in increased muscle mass, decreased at mass, increased acial hair and acne, male
pattern baldness, and increased libido. In emale-to-male individuals, testosterone therapy results in clitoromegaly,
temporary or permanent decreased ertility, deepened voice, vaginal atrophy, and cessation o menses.

Why use the term “Gender Con rmation Surgery” as opposed to “Sex Change” or “Gender Reassignment
Surgery”?
T e latter two phrases suggest that a person is making a choice to switch genders. Gender conf rmation surgery
should be seen as a therapeutic tool to enable a person to eel com ortable as their gendered sel .

What are the anatomic di erences between the male and emale chest that are relevant in top surgery?
T e male chest is wider than the emale chest, and the male pectoral muscle is usually more developed. T e male
areola is smaller than the emale areola, and the distance between the nipple and in ramammary crease is shorter in
males.

What are the methods o top surgery per ormed or emale-to-male individuals?
A subcutaneous mastectomy with varying incisions (and possible ree nipple gra t) is per ormed. T e technique
depends upon on skin elasticity, breast volume, and breast ptosis. T e double-incision technique (in ramammary
crease with ree nipple-areolar gra t) is the most commonly per ormed procedure. Other incisions, such as
periareolar and short vertical incisions, may also be per ormed.

CHAPTER 89 Gender Conf rmation Surgery
837

What is breast binding?
Breast binding is a practice commonly per ormed by emale-to-male individuals in order to atten the breasts.
T is may lead to a loss o skin elasticity, thereby necessitating skin removal at the time o chest wall contouring
surgery.

What are the most common types o breast surgery per ormed or male-to- emale individuals?
Breast augmentation is most o ten per ormed through an in ramammary crease incision. ransaxillary or
periareolar incisions may also be per ormed, and the use o shaped implants is gaining popularity.

What are the surgical options or sexual reassignment surgery (SRS) or vaginoplasty in male-to- emale
individuals?
T ere are three options: (1) penile disassembly and inversion vaginoplasty; (2) intestinal transplantation; and (3)
nongenital aps.

What are the typical components o vaginoplasty?
T ey include: (1) ormation o a neovagina using penile and scrotal (or sigmoid colon in the case o intestinal
vaginoplasty); (2) ormation o a neoclitoris, typically ormed rom the dorsal glans penis; (3) shortening o
urethra; and (4) ormation o labia minora and majora.

What are the potential complications o vaginoplasty?
T ere is risk o rectal injury, which, when recognized intraoperatively, should be repaired in two layers
and drained. T e use o diverting colostomy may be required in the case o rectovaginal f stula. Additional
complications include, but are not limited to vaginal stenosis, lack o sensation, delayed wound healing, venous
thromboembolism, and urethral injury.

What are the long-term care instructions ollowing vaginoplasty?
Annual speculum exam and digital prostate exam are per ormed. Routine vaginal dilation by the patient is
required in order to prevent vaginal stenosis. Frequency o vaginal dilation may be reduced with sexual intercourse.
Intermittent intravaginal washing (douching) is per ormed once or twice weekly using dilute povidone-iodine
solution or mild soap.

What are the advantages o intestinal transplantation?
T e ability to create a vascularized neovagina with a moist lining. T is may lessen the need or postoperative
vaginal dilation as well as the need or lubrication during intercourse.

What are the drawbacks o intestinal transplantation?
T e need or an intra-abdominal operation with a bowel anastomosis, possibility o diversion colitis in the
de unctionalized sigmoid colon, risk o GI malignancy, and small amounts o postcoital bleeding as a result o
riable colonic mucosa.

Does estrogen hormone therapy present a perioperative risk?
Yes. Estrogen hormone therapy should be discontinued approximately 2 weeks prior to surgery to reduce the risk
o venous thromboembolism.

838
Plastic & Reconstructive Surgery Board Review

What are the surgical options or bottom surgery or genital surgery in emale-to-male individuals?
T e options are metoidioplasty versus pedicled/ ree ap phalloplasty. Both phalloplasty and metoidioplasty
procedures may be combined with vaginectomy and scrotoplasty. Hysterectomy and oophorectomy are typically
per ormed prior to phalloplasty or metoidioplasty. Staged placement o testicular implants and penile prostheses
may also be per ormed

What is metoidioplasty?
Metoidioplasty involves lengthening o the hormonally hypertrophied clitoris by release o the suspensory
ligament and resection o the ventral chordae. Lengthening o the emale urethra may be per ormed with the aid
o labia minora vaginal musculomucosal aps.

What are the most common complications associated with metoidioplasty?
Urethral f stula and strictures.

What are the f ap options or phalloplasty?
T e three most commonly used aps are: (1) radial orearm ap; (2) anterolateral thigh ap; and (3) latissimus
dorsi myocutaneous ap. T e radial orearm ap provides a sensate ap that is amenable to the tube-in-a-tube
design, but leaves a noticeable donor site. T e bulk o the anterolateral thigh ap prohibits tubularization, and the
latissimus ap lacks sensation.

What is an option or vascular anastomoses and nerve coaptations?
T e radial artery is typically anastomosed end-to-side to the common or superf cial emoral artery, and the
cephalic vein anastomosed end-to-end to the greater saphenous vein. Additional venous anastomoses between the
basilic and median cubital veins to the superf cial in erior epigastric and superf cial circum ex iliac veins may also
be per ormed. T e medial and lateral antebrachial cutaneous nerves may be coapted to the ilioinguinal nerve and
dorsal clitoral nerve or protective sensation and erogenous sensation, respectively.

Does the WPATH Standards o Care recommend a re erral rom a mental health pro essional or other
surgeries?
No. Other surgeries such as acial eminization surgery, acial masculinization surgery, reduction thyroid
chondroplasty, voice surgery, etc. do not require a re erral according to the Standards o Care. However, mental
health pro essionals can play an important role in assisting transgender individuals in making a ully in ormed
decision about the timing and implications o such procedures.

What are the characteristic di erences between a masculine and eminine orehead?
When compared to a masculine orehead, the eminine orehead is shorter and has a more continuous, convex
curvature. T e masculine orehead has more pronounced supraorbital bossing due to larger rontal sinuses. T e
emale eyebrow is located above the supraorbital rim and has more o an arched appearance, whereas the male
eyebrow typically sits at the supraorbital rim.

What are the characteristic di erences between a masculine and eminine nose?
T e eminine nose is overall smaller than the masculine nose. T e masculine nose is associated with a more acute
naso rontal angle. In addition, the nasolabial angle is more obtuse in the eminine nose due to an upturning nasal
tip.

CHAPTER 89 Gender Conf rmation Surgery
839

What are the characteristic di erences between a masculine and eminine mandible?
T e masculine mandible has a more acute angle and greater lateral aring due to a thicker masseter muscle.
T is results in lower ace ullness when compared to the narrower, and more tapered, eminine lower ace. T e
eminine chin is smaller in both the vertical and horizontal dimensions, resulting in a narrower and more pointed
appearance.

What are the surgical techniques or acial eminization?
T e techniques include: (1) supraorbital burring or rontal osteotomy with set back; (2) brow li t; (3) anterior
hairline advancement or hair transplantation; (4) eminizing rhinoplasty; (5) mandibular angle reduction; and (6)
reduction genioplasty.

What are the surgical techniques or acial masculinization?
T e techniques include: (1) orehead augmentation; (2) mandibular angle implant augmentation; and (3) implant
or sliding genioplasty.

What is reduction thyroid chondroplasty?
An outpatient procedure per ormed either open or endoscopically to lessen the appearance o the “Adam’s apple”
or prominent thyroid cartilage.

What is voice surgery?
Various techniques designed to shorten the vocal cords, increase vocal cord tension, or reduce the vibrating vocal
cord mass in order to raise vocal pitch. Estrogen hormone therapy does not commonly a ect vocal pitch, and this
may result in residual stigma o masculinity.
REFERENCES
Coleman E, Bockting W, Botzer M, et al. Standards o care or the health o transsexual, transgender, and gender-noncon orming
people, version 7. Intl J Transgend. 2012;13(4):165–232.
Hage JJ. Metaidioplasty: an alternative phalloplasty technique in transsexuals. Plast Reconstr Surg. 1996;97:161–167.
Kwun Kim S, Hoon Park J, Cheol Lee K, et al. Long-term results in patients a ter rectosigmoid vaginoplasty. Plast Reconstr Surg.
2003;112(1):143–151.
Monstrey S, Selvaggi G, Ceulemans P, et al. Chest-wall contouring surgery in emale-to-male transsexuals: a new algorithm. Plast
Reconstr Surg. 2008. 121(3):849–859.
Ousterhout DK. Dr. Paul essier and acial skeletal masculinization. Ann Plast Surg. 2011;67(6):S10–S15.
Ousterhout DK. Feminization o the orehead: contour changing to improve emale aesthetics. Plast Reconstr Surg. 1987;79(5):701–713.
Schechter LS. Surgery o gender identity disorder. In: Song DH, Neligan PC. Plastic Surgery. Trunk and Lower Extremity. 3rd ed. Volume
4. Philadelphia, PA: Elsevier Health Sciences; 2012.
Selvaggi G, Ceulemans P, De Cuypere G, et al. Gender identity disorder: general overview and surgical treatment or vaginoplasty in
male-to- emale transsexuals. Plast Reconstr Surg. 2005;116(6):135e–145e.
Selvaggi G, Monstrey S, Hoebeke P, et al. Donor-site morbidity o the radial orearm ree ap a ter 125 phalloplasties in gender identity
disorder. Plast Reconstr Surg. 2006;118(5):1171–1177.

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841
Jenna Cusic, MD and
Patrick Hettinger, MD
DEFINITIONS

What is the di erence between an extravasation and an inf ltration?
• Extravasation
• Leakage o a vesicant (most common de nition).
• Administration o a harsh solution that causes vein damage leading to rupture.
• In ltration
• Leakage o an irritant (most common de nition).
• Administration o a solution outside a vein into surrounding tissues.

What is a vesicant?
• Agent that is inherently toxic, which may cause blistering, sloughing, or deep tissue damage.
• T ey have a wide range o necrotic potential.
• Examples include, calcium solutions, potassium solutions, radiographic contrast, sodium bicarbonate,
vasoconstrictor agents, doxorubicin, uorescein, mitomycin-C, vinblastine, and vincristine.

What is an irritant?
• Agent that is not directly toxic, which may cause an in ammatory reaction with erythema, warmth, and
tenderness.
• Examples include, albumin, blood products, asparginase, bleomycin, cyclophosphamide, methotrexate,
cisplatin, uorouracil, and valium.

What is a nonirritant?
Agent that is nontoxic and rarely produces an acute reaction.
Inf ltration and
Extravasation Injuries
CHAPTER 90

842
Plastic & Reconstructive Surgery Board Review

Can an irritant produce the same symptoms as a vesicant?
• Any agent in high enough concentration or volume may become an irritant or vesicant.
• A vesicant may not always produce necrotic tissue changes depending on the volume, concentration, or in usion
rate.
EPIDEMIOLOGY, RISK FACTORS, AND COMPLICATIONS

What is the incidence o extravasation?
• Many go unreported, thereby the true incidence is di cult to ascertain.
• Extravasation injury has been generally reported at 0.1% to 6%, yet has been documented up to 22% o
cytotoxic administrations.

Which agents may cause an extravasation/inf ltration injury?
Maintenance uids, electrolytes, blood products, chemotherapeutic agents, vasopressors, antibiotics, anesthetic
agents, other medications, PN, and contrast agents.

What are the risk actors or extravasation/inf ltration?
• Unable to communicate pain—in ants or elderly, nonverbal or cognitive impairment, ICU, under anesthesia.
• Decreased sensation—neuropathy (diabetic or chemotherapy side ef ects).
• Comorbidities—peripheral vascular disease, Raynaud phenomenon, and diabetes.
• Vessels and their ow—lymphedema, obstructed vena cava, venous hypertension; chemotherapy patients have
ragile, mobile veins.
• Procedure technique—multiple attempts, large gauge or metal needles, bolus or high ow injections.
• Agents—vesicants, high osmolarity, extremes o pH, and vasoconstrictive agents.

What complications may ensue rom extravasation/inf ltration?
• Pain, scarring (aesthetically displeasing and unctional impairment), unctional loss (consider character o
surrounding tissue such as thickness o skin, as well as underlying structures such as neurovascular structures or
tendons/joints), so t-tissue loss, in ection, compartment syndrome, urther operations, and amputations.
• Delay in oncological treatment i receiving chemotherapy or radiation.
• Longer hospital stays and increased costs.
PREVENTION

What strategies can be used or prevention?
Check IV site on an hourly basis and recognize high-risk patients; optimize veins (hot towels, nitroglycerin); use
the smallest needle appropriate in a larger vein; avoid multiple per orations to the same vein (second attempt made
more proximal), unnecessary dressings, extremities with lymphedema, in usion under pressure; use large or central
veins or resuscitative ef orts; and maximally dilute chemotherapy agents.

CHAPTER 90 In ltration and Extravasation Injuries
843
PATHOPHYSIOLOGY

What are the pathophysiologic mechanisms o extravasation/inf ltration?
• In usion o the agent.
• Leakage around the cannulation site o in usion directly into the surrounding tissues.
• Occlusion o distal ow due to pressure rom extravasated uid into interstitial space or local irritation,
including phlebitis, vasoconstriction or thrombosis increases intraluminal pressure leakage o agent.
• In usion with high pressure or large volumes increases extracellular hydrostatic pressure venous
compression urther extravasation/in ltration arterial compromise.
• May lead to compartment syndrome.
• Increased height rom which uid travels into the vein leads to increased pressure; the higher the IV uid
bag, the higher the potential pressure o in usion.
• Pressure (mm Hg) = 0.7418 × height o uid column (cm) – 6.109
• Agent properties.
• Osmotic damage, ischemic damage, direct cellular toxicity, and bacterial colonization.

How may osmolarity induce damage to tissues?
• Hypertonic solutions, PN, contrast media, antibiotics, and cations in ionized orm.
• Pulls uid rom intracellular to extracellular dehydration and death o cells, disruption o transport
mechanisms, and increased interstitial uid and pressure leading to compartment syndrome.
• Calcium and potassium salts can cause cell death by cellular uid overload.

How may ischemic damage be induced rom extravasation?
• Vasopressor agents lead to vasoconstriction lack o tissue per usion.
• α-adrenergic agonists–epinephrine, norepinephrine, dopamine, and phenylephrine.
• Duration o ef ect has more impact that concentration.
• V1 agonists–vasopressin.
• Cation solutions cause prolonged depolarization contraction o vascular smooth muscle lack o tissue
per usion.

How may cells be directly damaged through extravasation?
• Ions can orm salts and precipitate proteins, killing cells.
• DNA-binding agents cause an ongoing lethal cycle.
• Kill the cells, releasing agent into surrounding tissue agent is taken up by another cell kill the cells,
releasing agent into tissue, etc.
• Agents with extremes o pH may be caustic to endothelial tissue.
• Direct local damage by agent or its vehicle.

How does extravasation a ect tissues via bacteria?
Open wounds may become colonized and can increase extent o wound and impair healing.

844
Plastic & Reconstructive Surgery Board Review
PRESENTATION

What are the signs and symptoms o extravasation/inf ltration?
• Patient report or physical examination—pain, swelling, erythema or discoloration, induration, and blistering.
• Character o in usion—change in rate (usually slows with increased resistance), lack o blood return.

What are the grades o extravasation/inf ltration by clinical examination?
Grade 1

Blanched skin.
Edema < 1 inch in any direction.
Cool to touch.
With or without pain.
Grade 2

Same as above in addition to
• Edema 1 to 6 inches in any direction.
Grade 3

Same as above in addition to
• Blanched, translucent skin.
• Gross edema >6 inches in any direction.
• Mild to moderate pain.
• Possible numbness.
Grade 4

Same as above in addition to
• Tight, leaking, discolored/bruised, and swollen skin.
• Deep pitting edema.
• Circulatory impairment.
• Moderate to severe pain.
• All extravasations.
Grading should be assigned by most severe clinical indicator of injury.

What details o extravasation/inf ltration are important to obtain?
• Agent, as this will guide treatment and administration o potential antidotes.
• Vesicant versus irritant; DNA-binding versus non–DNA-binding vesicant.
• Concentration.
• Volume administered and orce o in usion.
• iming o in usion
• Antidotes have limited time intervals to be administered; necrosis interval (see below text)
TREATMENT

What are the immediate interventions?
• Stop the in usion, leave the catheter in place and aspirate any available uid.
• Elevate the extremity/area.
• Obtain the details o extravasation/in ltration.

CHAPTER 90 In ltration and Extravasation Injuries
845

What are the def nitive interventions?
• Warm or cold compresses.
• Administration o hyaluronidase i indicated (see below).
• Steroid creams—evidence is controversial, but considered to decrease in ammation.
• Administer antidotes i available.
• Phentolamine within 12 hours a ter extravasation o α-adrenergic agents; may also provide some bene t with
other vasoconstrictive agents like vasopressin.
• Derazoxane within 6 hours a ter extravasation o anthracyclines (doxorubicin).
• Normal saline in usion techniques to dilute agent.
• Gault technique and variants (see below).
• Surgical intervention i warranted.
• Consider the necrosis interval, and the timing and severity o extravasation.
• Rehabilitation.

Should a warm or cold compress be used?
Depends i a “dilute and disperse” or “localize and neutralize” ef ect is indicated.

What is the e ect o a warm compress?
• Vasodilation, which increases local blood ow and dilutes and disperses the agent.
• Used in conjunction with hyaluronidase.
• PN, mannitol, calcium, potassium, phenytoin, and contrast media.

Are there instances when a warm compress should not be used?
• Yes, as it could increase the area o toxicity by dispersing the agent.
• Do not use with DNA-binding vesicants.

What is the e ect o a cold compress?
• Vasoconstriction, which decreases in ammation and keeps the agent localized.
• Can decrease cellular uptake o the agent.
• Used or DNA-binding vesicants; may be used or contrast media (may also use warm pack).
• Generally acceptable or chemotherapeutic agents except non–DNA-binding vesicants.

Are there instances where cold compresses should not be used?
• Yes, vinca alkaloids (type o non–DNA-binding vesicant) as this may increase tissue ulceration.
• Vincristine, vinblastine.

How does hyaluronidase assist with treatment?
Reversibly breaks down hyaluronic acid (dominant GAG in connective tissue) decreases viscosity increases
tissue permeability absorption and dispersal o agent.

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Plastic & Reconstructive Surgery Board Review

When should hyaluronidase be injected?
• Within 1 hour o extravasation.
• May be used or vinca alkaloids, calcium, potassium, hypertonic glucose, PN, and mannitol, among other
agents.
• Avoid with vasoconstrictive agents, DNA-binding vesicants, controversial in contrast media.

Which conditions may predispose resistance to hyaluronidase?
• Large doses o corticosteroids, salicylates, estrogens, and antihistamines.
• Elderly may be less responsive due to their skin inelasticity.

What is the “Gault technique”?
• Saline ushout o the extravasated/in ltrated area.
• Hyaluronidase is in ltrated, stab incisions around periphery o af ected area are made and normal saline is
ushed through a blunt ended cannula in 20 to 50 cc aliquots, up to 500 mL total.
• Fluid returned can be analyzed or extravasated/in ltrated agent.
• Area may also be liposuctioned.
• Variations o liposuction and normal saline clysis have been shown in a number o studies to result in improved
rates o ulceration and so t tissue damage, as well as preserved unction, even in cytotoxic extravasations.

What is the necrosis interval?
• ime rom extravasation to point o irreversible tissue damage.
• Early surgical intervention within this time rame may prevent necrosis.
• Vasopressor agents: 4 to 6 hours.
• Radiographic contrast agents: 6 hours.
• Chemotherapeutic agents: 72 hours.

What determines “wait and see” approach versus “early surgical intervention”?
• May generally observe a mild or moderate injury consisting o an irritant or a small volume, low concentration
vesicant, with no blistering or necrosis.
• Consider early surgical intervention with severe injuries, including vesicant extravasations, large volumes, tissue
necrosis, or within the necrosis interval o vasopressors, contrast media, or chemotherapeutic agents.
• On examination, the amount o tissue damage is o ten underestimated.
• Early surgical intervention within 72 hours o severe injuries or within the necrosis interval o respective
agents can improve outcomes.

How are vasopressors deleterious to tissues?
• Vasoconstriction leads to tissue ischemia.
• α-adrenergic receptors (epinephrine, norepinephrine, phenylephrine, and dopamine) or V1 receptors
(vasopressin).
• Generally acidic, causing local tissue toxicity.

How may vasopressor extravasation injury present?
Blanching, swelling, erythematous or purple discoloration, bullae and eventually an eschar or gangrene.

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What are early interventions or vasopressor extravasations?
• Do not place a cold pack (already vasoconstricted) or give hyaluronidase (can extend ischemic area).
• Phentolamine—competitive α-receptor antagonist vasodilation.
• Antidote or α-agonist agents, and may also indirectly improve vasopressin extravasation.
• May see partial reversal o ischemia within 7 to 10 minutes.
• Inject into subcutaneous area within 12 hours.
• erbutaline–β 2-agonist vasodilation.
• Second-line agent.
• Use with caution in underlying cardiac disease, as it may induce arrhythmias or myocardial in arction in
at-risk populations.
• opical nitroglycerin–increases cGMP vasodilation.
• Stellate ganglion block–blocks sympathetic input, decreasing vasoconstriction.

What are the early interventions or mannitol?
• Warm compresses, hyaluronidase.
• Hyperosmolarity can cause extreme edema, potentially leading to compartment syndrome; dispersion and
dilution o the agent will assist in decreasing its ef ect.

What are the early interventions or TPN?
• Warm or cold compresses have been proposed; hyaluronidase may also be used.
• PN is hyperosmotic and acidic.

Is calcium gluconate or calcium chloride more detrimental?
• Calcium chloride’s osmolarity is 2,040 mOsm/L and it dissociates more extensively with a higher risk o
precipitation, whereas calcium gluconate’s osmolarity is 669 mOsm/L.
• Absolute calcium content may be the strongest predictor o tissue necrosis due to direct protein precipitation
and vasoconstriction.
• Calcium may cause ischemic necrosis rom prolonged depolarization or may precipitate proteins and cause
cellular toxicity.

How may calcium extravasation present?
• Early—erythema and pain progressing to eschar ormation and eventually necrosis, but may take weeks to
develop.
• Late—calcinosis cutis.

What is calcinosis cutis?
Extravasation o calcium, leading to so t tissue calci cation through ormation o hydroxyapatite; orms
subcutaneous white to yellow plaques that are visible in radiographs.

What are the possible interventions or calcium extravasation?
• Hyaluronidase.
• Sodium thiosul ate— orms calcium thiosul ate which has a higher solubility.
• Surgical resection.

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What is “purple glove syndrome”?
• Phenytoin related so t-tissue injury.
• Phenytoin is hyperosmolar and alkalotic, and may orm precipitates leading to thrombosis.
• T ree phases:
• Pain and purple/blue discoloration distal to venous access site.
• Glove-like circum erential erythema with edema.
• Bullae ormation, skin necrosis, and possible compartment syndrome.
• One-third o patients progress to this phase.

What are the potential treatments or phenytoin extravasation?
• Warm compresses, hyaluronidase.
• May prevent injury with a lower rate o in usion.
• Surgical intervention.

What are examples o chemotherapeutic DNA-binding and non–DNA-binding agents?
• DNA-binding
• Anthracyclines—doxorubicin, daunorubicin, epirubicin, and idarubicin.
• Alkylating agents—mechlorethamine.
• Other—mitomycin.
• Non–DNA-binding
• Vinca alkaloids—vincristine, vinblastine.
• axanes—paclitaxel.

Why do DNA-binding vesicants have the potential to be so detrimental?
• T ey orm a vicious cycle o cell death agent is released and taken up by another cell cell death agent is
released, etc.
• May present early to late with ongoing and extensive tissue damage.

What is the “recall e ect”?
Reactivation o skin toxicity with administration o chemotherapy or radiation at a remote site.

How do doxorubicin extravasations present?
• Progressive, central necrosis with raised, erythematous, and pain ul edges.
• T ese injuries heal slower as they contain chronic broblast disorganization; they show a delayed presence o
myo broblasts.

Can doxorubicin cause local irritation?
Doxorubicin in usion may cause a local “ are” which usually subsides within 1 to 2 hours.

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What are the initial treatments or doxorubicin extravasation?
• Cold compresses, as this is a DNA-binding agent and should be localized, not dispersed, to avoid extending the
area o injury.
• Dexrazoxane is the rst-line antidote, but needs to be administered within 6 hours.
• Free radical scavenger inhibits topoisomerase II.
• Side ef ects: transient transaminitis, slight myelosuppression.
• Dimethyl sul oxide (DMSO) may also be used.
• Neutralizes ree radicals, may cause vasodilation.

I surgical intervention is required, what may be used to assess that doxorubicin laden tissue is removed?
UV light causes doxorubicin tissue to glow reddish/orange.

I surgical intervention is required, what may be used to assess that contrast media laden tissue is removed?
Obtain x-ray imaging, which will reveal location o contrast media i it remains in tissues.
REFERENCES
Al-Benna S, O’Boyle C, Holley J. Extravasation injuries in adults. ISRN Dermatol. 2013:856541.
Ball R, Henao J. Ibinson JW, Metro DG. Peripheral intravenous catheter in ltration: anesthesia providers do not adhere to their own
ideas o best practice. J Clin Anesth. 2013;25:115–120.
Boulanger J, Ducharme A, Du our A, et al. Management o the extravasation o anti-neoplastic agents. Support Care Cancer. 2015;
23(5):1459–1471.
Erickson BA, Yap RL, Pazona JF, Hartigan BJ, Smith ND. Mannitol extravasation during partial nephrectomy leading to orearm
compartment syndrome. Int Braz J Urol. 2007;33(1):68–71; discussion 71.
Gault D . Extravasation injuries. Br J Plast Surg. 1993;46:91–96.
Hahn JC, Sha ritz AB. Chemotherapy extravasation injuries. J Hand Surg Am. 2012;37:360–362.
Hannon MG, Lee SK. Extravasation injuries. J Hand Surg Am. 2011;36:2060–2065.
Khan MS, Holmes JD. Reducing the morbidity rom extravasation injuries. Ann Plast Surg. 2002;48:628–632.
Kumar RJ, Pegg SP, Kimble RM. Management o extravasation injuries. ANZ J. Surg. 2001;71:285–289.
Larson D. reatment o tissue extravasation by antitumor agents. Cancer. 1982;49:1796–1799.
Le A, Patel S. Extravasation o noncytotoxic drugs: a review o the literature. Ann Pharmacother. 2014;48(7):870–886.
Loth , Eversmann W. Extravasation injuries in the upper extremity. Clin Orthop Relat Res. 1991;272:248–254.
Napoli P, Corradino B, Badalamenti G, et al. Surgical treatment o extravasation injuries. J Surg Oncol. 2005;91:264–268.
Reynolds P, MacLaren R, Mueller S, Fish DN, Kiser H. Management o extravasation injuries: a ocused evaluation o noncytotoxic
medications. Pharmacotherapy. 2014;34(6):617–632.
Rhys-Davies NC, Stotter A . T e Rhys-Davies exsanguinator. Ann R Coll Surg Engl. 1985;67:193–195.
Rudolph R, Larson DL. Etiology and treatment o chemotherapeutic agent extravasation injuries: a review. J Clin Oncol. 1987;7(5):
1116–1126.
Schaverien MV, Evison D, McCulley SJ. Management o large volume C contrast medium extravasation injury: technical re nement
and literature review. J Plast Reconstr Aesthet Surg. 2008;61:562–565.
o ani BF, Rineair SA, Gosdin CH, et al. Quality improvement project to reduce in ltration and extravasation events in a pediatric
hospital. J Pediatr Nurs. 2012;27:682–689.
sai YS, Cheng SM, Ng SP, et al. Squeeze maneuver: an easy way to manage radiological contrast-medium extravasation. Acta Radiol.
2007;48:605–607.
savaris NB, Karagiaouris P, zannou I, et al. Conservative approach to the treatment o chemotherapy-induced extravasation.
J Dermatol Surg Oncol. 1990;16:519–522.
savaris NB, Komitsopoulou P, Karagiaouris P, et al. Prevention o tissue necrosis due to accidental extravasation o cytostatic drugs by
a conservative approach. Cancer Chemother Pharmacol. 1992;30:330–333.
Upton J, Mullliken JB, Murray JE. Major intravenous extravasation injuries. Am J Surg. 1979;137:497–506.

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GENERAL TOPICS
Section VIII

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Pieter G.L. Koolen, MD
DESCRIPTIVE STATISTICS

Why use descriptive statistics?
• o describe the basic characteristics o a data set.
• o identi y patterns in your data set.
• o generate hypotheses.

What are common measures o central tendency?
• Mean.
• Median.
• Mode.

What is the mean?
T e statistical average.

How is the mean estimated?
o estimate the mean, sum up all the values and divide the sum by the number o values.

What is the median?
T e exact “middle” value.

How is the median determined?
Sort the data rom the lowest to the highest value and nd the value in the middle. I there is an even number o
data points, average the two values in the middle.

When the data are highly skewed, which measure o central tendency is pre erred?
T e median because the mean is sensitive to outliers or data points that are very di erent than most others.
Basic Statistical Methods
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What is the most requently occurring score in a set o scores?
T e mode.

Measures o dispersion include?
• Range.
• Standard deviation.
• Standard error.

What does the standard deviation describe?
• How spread out the values are in a data set, OR
• How closely the values o a data set cluster around the mean value.

What is the standard error?
T e standard error re ers to the likelihood that the mean and standard deviation o a speci c sample o participants
ref ect the mean and standard deviation o the ull population o potential participants. It is computed by dividing
the standard deviation by the square root o the sample size (n).

What is the range?
T e distance between the minimum value and maximum value.

What is the interquartile range?
T e distance between the 25th and 75th percentiles.
TYPES OF VARIABLES

What is a categorical variable?
A variable made o categories that cannot be quanti ed (e.g., blood type, gender, and pregnant/not pregnant).

What kind o statistical analysis is appropriate or categorical variables?
Nonparametric statistics.

What is a continuous variable?
A variable that gives a score or each subject in a sample and can take on any value on a measurement scale
(e.g., blood pressure and cholesterol).

What kind o statistical analysis is appropriate or continuous variables?
Parametric statistics.

What is an ordinal variable?
An ordinal variable is a variable that is recorded on an interval scale rom highest to lowest but does not involve use
o the numerical relationship between numbers (e.g., having patients rate their level o pain on a scale rom 1 to 10).

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What kind o statistical analysis is appropriate or ordinal variables?
echnically, nonparametric statistics are most appropriate or ordinal variables, but researchers o ten use
parametric statistics.

What is the di erence between parametric and nonparametric tests?
Parametric tests assume that the data are normally distributed and nonparametric tests are typically more stringent
because they are based on the assumption o nonnormal distribution.
Examples o parametric tests and the nonparametric equivalent
Param etric Test

Nonparam etric Test
Ratio or interval data

Ordinal or nominal
Two-sample unpaired t-test

Mann–Whitney U-test or Wilcoxon rank-sum test
One-sample matched pairs t-test

Wilcoxon matched pairs test
One-way ANOVA (F-test)

Kruskal–Wallis analysis o variance by ranks
One-way repeated-measures ANOVA

Friedman ANOVA test
Chi-square

Fisher exact test
Pearson r—product moment correlation coe f cient Spearman rank correlation coe f cient
INFERENTIAL STATISTICS

T e probability that any particular outcome would have occurred by chance is known as?
T e P value: the probability o the observed result or something more extreme under the null hypothesis.

What is a conf dence interval?
A range o values around the sample mean within which a researcher can be certain (typically 95% certain)
contains the true mean o the population.
PARAMETRIC TESTS

What types o analysis can you use when both variables are continuous?
• Regression.
• Correlation.

What does regression analysis mean?
Whether you can predict the value o one variable (the dependent variable) rom the value o another variable (the
independent variable) (e.g., predicting a patient’s cholesterol level rom the number o years he or she has been
smoking).

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What is the statistic or a regression called?
R2.

What does a B or β mean when it is reported with regression results?
T at is the value by which the independent variable must be multiplied to determine the value o the dependent
variable.
Note: most journals now require researchers to report the 95% con dence interval around the B or β.

What is a correlation?
Examining whether two variables are positively or negatively related to each other (e.g., weight and height).

What is the statistic or a correlation called?
r.

What is the range or r?
+ 1 to −1.

What does a + 1 r-value mean?
wo variables are per ectly positively related to each other (as one increases so does the other).

What does a −1 r-value mean?
wo variables are per ectly inversely related to each other (as one increases the other decreases).

What is a partial correlation?
It is essentially a correlation you can run with three values. It involves correlating two values to each other, while
accounting or the correlation each value has with a third value (e.g., removing the correlation with age while still
examining a correlation between height and weight).

What type o analysis can you use when one variable is categorical and the other variable is continuous?
• t-tests.
• analysis of variance (ANOVA).

What does a t-test involve?
Examining whether two groups o participants signi cantly di er on a variable (e.g., comparing ndings between
a control group and an experimental group).

What does an ANOVA involve?
Examining whether two or more groups signi cantly di er on a variable. You can use this when you have more
than one experimental group.

What is an omnibus F-test?
T is tells you whether there is an overall di erence between your groups.

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How can you compare multiple groups to each other within an ANOVA?
• Planned contrasts.
• Posthoc tests (e.g., Bon erroni and ukey).

What tests do you use when you want to compare only one or two o your groups to each other?
Planned contrasts (e.g., compare experimental group 1 to the control group and experimental group 2 to the
control group, but not experimental groups 1 and 2 to each other).

What tests do you use when you want to compare all o your groups to each other?
Posthoc tests (e.g., compare the control group with both experimental groups and the experimental groups to each
other).
NONPARAMETRIC TESTS

When is logistic regression appropriate?
When you want to predict a dichotomous variable rom a continuous variable (e.g., predicting whether someone is
male or emale rom knowing their weight).

When is a Wilcoxon signed-ranks test appropriate?
T is test unctions as a t-test or ordinal variables (e.g., examining whether the control group and the experimental
group di er in their pain ratings).

o determine i a di erence exists between two di erent groups, which statistical test is most appropriate?
Mann–Whitney U-test.

What are the characteristics o the Mann–Whitney U-test?
• Used to determine i a di erence exists between two di erent groups.
• Equivalent to the two-sample t-test.
• Nonparametric test.

T e Wilcoxon rank-sum test is equivalent to which other statistical test?
• T e Mann–Whitney U-test.
• Used to test di erences between two conditions and di erent subjects in each condition.

What is an appropriate test to determine the relationship between two categorical variables?
Pearson chi-square test.

What does a Pearson chi-square test involve?
It is a hypothesis test which may be per ormed on contingency tables and is used to discover i there is a
relationship between two categorical variables (e.g., being emale and having breast cancer).

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TYPES OF ERROR

T e probability o alsely rejecting the null hypothesis is what type o error?
ype I error.

When a researcher concludes that there is a di erence between two conditions when there is no di erence,
the researcher is making what type o error?
ype I error.

What is a ype II error?
Probability o ailing to reject the null hypothesis when it is true, and the researcher concludes there is no
di erence between two conditions when there is a real di erence.

What is a null hypothesis?
T at there is no real di erence between two groups (or treatments).

What is the purpose o the binomial test?
Used to compare two dichotomous variables to each other and i you want to know i the proportion o
individuals alling into each category has resulted rom chance.

What is the term that re ers to the statistical likelihood that a researcher will f nd a signif cant e ect that
exists based on the sample size and number o variables?
Power.

What determines how many degrees o reedom you have or a particular test?
T e number o participants and the number o variables in your analyses.
EVIDENCE-BASED MEDICINE

What is evidence-based medicine?
Clinical decision making based on the integration of research, clinical expertise, and patient needs.

How many di erent levels o evidence are there?
Five.

What is Level I type o evidence?
T e highest quality o evidence (e.g., systematic reviews or randomized controlled trials).

What is Level II type o evidence?
Evidence gathered rom a lesser quality randomized clinical trial (e.g., high attrition rates, improper randomization
o subjects, or nonrandomization o subjects) or a cohort study or systematic review o such studies.

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What is Level III type o evidence?
Evidence gathered rom a well-designed quasi-experimental study (e.g., case–control study or systematic review o
such studies).

What is Level IV type o evidence?
Evidence gathered rom well-designed nonexperimental study (e.g., descriptive studies and case series).

What is Level V type o evidence?
Evidence gathered rom expert opinion, case reports, and clinical examples. T is is the weakest level o evidence.
ASSESSMENT OF DIAGNOSTIC STUDIES

What is sensitivity?
T e probability that a patient with a disease will have a positive test result.

What is specif city?
T e probability that a patient without a disease will have a negative test result.

What is the positive predictive value (PPV)?
T e probability that a patient with a positive test result has the disease. T e more speci c a test, the higher is
its PPV.

What is the negative predictive value (NPV)?
T e probability that a patient with a negative test result does not have the disease. T e more sensitive a test, the
higher its NPV.
BIAS IN STUDY DESIGN

What is a selection bias?
When participants or samples are selected that di er rom other groups in additional determinants o outcome.
T e sample obtained is not representative o the population intended to be analyzed.

What is a con ounding bias?
T e di erential e ect o unknown or uncontrolled actors on study groups.

What is a measurement/in ormation bias?
A systematic error in the measurement o the outcome.

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What is a recall bias?
A di erence between two groups caused by the inaccuracy o retrospective recollections retrieved.

What is a lead time bias?
Results when comparing two screening tests and the new or experimental test identi y the disease earlier than the
traditional test, thus giving the impression o prolonged survival.
REFERENCES
Field A. Discovering Statistics Using SPSS. Los Angeles, CA: Sage; 2009.
Garrett-Mater E. Basic Biostatistics for Clinicians: How to Use and Interpret Statistics. Available online at:
talks/BasicBiostatisticsforClinicians.pdf.
Greenhalgh . Statistics or the non-statistician I: di erent types o data need di erent statistical tests. BMJ. 1997;315:364–366.
Greenhalgh . Statistics or the non-statistician II: “Signi cant” relations and their pit alls. BMJ. 1997;315:422–425.
Rich NC. Levels of Evidence. J Womens Health Phys T er. 2005;29:2.
Sackett DL, Strauss SE, Richardson WS, et al. Evidence-Based Medicine: How to Practice and each EBM. Philadelphia, PA: Churchill-
Livingstone; 2000.
Sackett DL, Rosenberg WM, Gray JA, Haynes RB, Richardson WS. Evidence based medicine: what it is and what it isn’t. BMJ.
1996;312:71–72.
Siegel S. Nonparametric Statistics for the Behavioral Sciences. New York, NY: McGraw-Hill; 1956.
Song JW, Hass A, Chung KC. Applications of statistical tests in hand surgery. J Hand Surg Am. 2009;34(10):1872–1881.
Witte RS. Statistics. 4th ed. Fort Worth, TX: Harcourt Brace; 1993.

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Emily M. Clarke-Pearson, MD, MEd
HEMATOLOGY/ BLOOD PRODUCTS

Name common supplements that should be discontinued to avoid increased bleeding risk.
Ginko biloba, garlic, ginseng, omega-3, vitamin E, chondroitin, and saw palmetto.

How should one manage a Jehovah’s Witness patient with a low preoperative Hgb?
First evaluate the patient or cause: iron de ciency (i.e., possible GI malignancy), renal dys unction, or olate/B12
de ciency. Once these causes o anemia are ruled out, the patient should be started on oral iron and recombinant
erythropoietin.

What are the indications or RBC trans usion?
Evidence o active bleeding/hemorrhagic shock or generally Hgb < 7 (Hgb < 8 in patients with acute coronary
syndromes). Previous guidelines to initiate trans usion or Hgb 10/Hct 30 have shown no bene t.

What is the most common acquired hypercoagulable disorder?
Smoking. Other common acquired causes: oral contraceptive pills, obesity, cancer, and antiphospholipid
syndrome.

T ree days a ter starting war arin on a patient skin begins sloughing skin o their arms and legs. What is the
most likely cause?
War arin induced skin necrosis may result i war arin is started without rst starting heparin. Protein C and S have
shorter hal -lives and decrease be ore the other vitamin-k dependent actors when war arin is initiated. T is leads
to hypercoagulable state and skin necrosis. reatment is heparin.

How do you treat a hemophiliac joint?
Do not aspirate. Elevate, range o motion exercises, and ice.
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General Surgery
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What is the most common location o a deep vein thrombosis?
Cal . However, ilio emoral DV s are most likely to cause a pulmonary embolus. Le t leg is twice as likely as right
because the le t iliac vein is compressed by the right iliac artery.
FLUIDS/ ELECTROLYTES/ NUTRITION

What are the indications or total parental nutrition ( PN)?
Enteral nutrition is always pre erred over parenteral nutrition. PN may be the only option or patients who
require total bowel rest or do not have a unctional GI tract (i.e., bowel obstruction, radiation enteritis, and
congenital GI anomalies).

What does PN ormula usually consist o ?
Water (30–40 mL/kg/day), protein (20% calories), at (30% calories), dextrose (50% calories), trace minerals,
vitamins, and electrolytes.

A patient presents or an elective procedure 3 months a ter thyroidectomy. What should you be cautious o ?
A common cause o hypocalcemia is iatrogenic injury. Check or signs o hypocalcemia (perioral tingling/
numbness, Chvostek’s sign, rousseau’s sign, and prolonged Q on EKG). You may need to correct Mg be ore
being able to correct Ca.

How can you assess a patient’s preoperative nutritional status?
Albumin (t1/2 18 days), trans errin (t1/2 8 days), and prealbumin (t1/2 2 days) are all use ul indicators o nutritional
status. Albumin < 2.5 and/or > 20% weight loss in 6 months are strong risk actors or morbidity/mortality.

What is a respiratory quotient (RQ)?
RQ is a measurement o energy expenditure (ratio o CO2 produced to O2 consumed). RQ is important or
patients who are ventilator dependent. RQ > 1 (lipogenesis) indicates high carbohydrate and CO2 buildup.
Conversely, RQ < 0.7 suggests at oxidation (starvation) and carbohydrates should be increased.

What is the bene t o D51/2NS maintenance IV f uid?
5% dextrose stimulates insulin release, amino acid uptake, and protein synthesis. When given at 125 cc/hr it
provides 150 g glucose/day.
ONCOLOGY

What is radiation enteritis?
GI toxicity may result when the radiation eld includes GI structures (thorax, abdomen, or pelvis). E ects include
early toxicity (i.e., diarrhea and nausea) and late toxicity (i.e., ulceration and stricture). Combining chemotherapy
with radiation increases the risk o radiation enteritis.

What is the di erence between a core needle biopsy (CNBx) and ne needle aspiration (FNA)?
CNBx gives architecture, FNA gives cytology.

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Is higher energy radiation worse or better or the skin?
Better, maximal ionizing potential is not reached until deeper structures.

In which cases is it appropriate to resect a normal organ to prevent cancer?
(1) Colon ( amilial adenomatous polyposis), (2) Breast (BRCA I/II with strong amily history), and (3) T yroid
(Ret protoncogene or MENIN gene with strong amily history).

What are the guidelines or biopsy o an extremity sarcoma?
Excisional biopsy or lesions < 4 cm and longitudinal incisional biopsy i > 4 cm. T e incisional biopsy is oriented
longitudinally so that the scar can be easily resected a ter re-excision or margins.
THORACIC

What anatomy is relevant to thoracic outlet syndrome?
T e thoracic outlet is the space between the clavicle and the rst rib. T e subclavian vein runs anterior to the
anterior scalene, the subclavian artery and brachial plexus run between the middle/anterior scalenes. Patients can
experience neurogenic, venous, or arterial mani estations o compression in this region.

What is a Pancoast tumor?
Superior pulmonary sulcus tumor. Invasion o the sympathetic chain leads to Horner’s syndrome (ptosis, miosis, and
anhydrosis) or ulnar nerve symptoms (weakness o intrinsic hand muscles and pain/paresthesia o 4th and 5th digits).

What are the key eatures o chylothorax and its treatment?
T e thoracic duct runs along the right side o the chest and crosses to the le t side at 4–5 in order to drain into
the le t subclavian vein. Chylothorax is o ten due to iatrogenic injury o the thoracic duct. Management usually
is conservative at rst (chest tube, octreotide, and low at diet). Surgical ligation can be per ormed i conservative
measures ail.

What is the best way to measure alveolar ventilation?
PaCO2 is the only blood gas measurement that gives you the relationship o alveolar ventilation to CO2
production.
HEAD AND NECK

Massive bleeding 1 week a ter tracheostomy creation is most likely:
racheoinnominate artery stula. First obtain bedside control o hemorrhage by overinf ating the cu or placing
your nger through the tracheostomy site to compress the innominate artery against the sternum. Urgent median
sternotomy in OR and then either ligate the innominate artery, bypass, or place interposition gra t.

In a trauma patient, what are di erent ways to treat elevated intracranial pressure (ICP)?
(1) Sedation/paralysis, (2) elevated head o bed, (3) relative hyperventilation (CO2 30–35), (4) keep serum Na
140–150 (may need hypertonic saline), (5) Mannitol, and (6) ventriculostomy with CSF drainage or burr hole/
craniotomy.

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What is Cushing’s triad?
(1) Hypertension, (2) bradycardia, and (3) slow respiratory rate. All three o these ndings in a patient with head
injury suggest impending herniation.
TRANSPLANT

Describe the di erent types o rejection?
Type of Rejection Tim e

Cause
Hyperacute

Minutes to hours Preformed antibodies against donor tissue
Acute

Days to weeks

T cells mediated against foreign MHC
Chronic

Months to years T cell mediated against foreign MHC “looking like” self MHC

Name the two most common posttransplant malignancies.
(1) Skin Ca (SSC #1) and (2) posttransplant lymphoproli erative disorder.

What is the mechanism o steroid use in transplant?
Steroids inhibit macrophages and genes or cytokine synthesis (IL-1 and IL-6).
ANESTHESIA/ AIRWAY MANAGEMENT

What is Rapid Sequence intubation (RSI)?
RSI allows or rapid control o the airway but using a ast acting induction agent and paralytic. RSI is o ten
used in emergency airway management or in patients that are high risk or aspiration (i.e., bowel obstruction,
pregnancy, and recent oral intake).

How do you per orm an open cricothyroidotomy?
Cricothyroidotomy is the last resort when an emergent airway is needed. A 1-cm vertical incision is made between
the in erior aspect o the thyroid cartilage and the superior aspect o the cricoid ring down to depth o laryngeal
structures. T en a horizontal incision is made near the in erior edge o the cricothyroid membrane (to avoid
superior cricothyroid vessels), then dilate and place an endotracheal/tracheostomy tube.

What are some advantages o dexmedetomidine (precedex) versus propo ol?
Dexmedetomidine is a selective α 2-agonist that provides “cooperative” sedation and analgesia without depressing
the respiratory drive. Patients may be extubated while on dexmedetomidine. Propo ol has a rapid on/o e ect o
complete sedation and does not have analgesic properties. Propo ol causes respiratory depression. Side e ects o
both medications may include bradycardia and hypotension.

CHAPTER 92 Special opics in General Surgery
865

How should patients on chronic steroids be managed postoperatively?
Function o hypothalamic–pituitary–adrenal (HPA) axis and need or perioperative steroids.
• Nonsuppressed HPA axis • Any dose of exogenous
steroids for < 3 wks.
• < 5 mg prednisone for
any duration or < 10 mg
prednisone every other
day.
• Do not require preop evaluation
of HPA axis or additional
steroids perioperatively.
• Suppressed HPA axis
• Prednisone > 20 mg/day for
> 3 wks.
• Minor procedures–no steroids.
• Moderate procedures–25 mg
hydrocortisone q8h × 24 hrs.
• Major procedure–100 mg IV
hydrocortisone before induction,
50 mg q8h × 24 hrs, taper
down.
Patients with intermediate HPA suppression require biochemical evaluation to determine severity o suppression.

What is malignant hyperthermia and how is it treated?
Malignant hyperthermia is a li e-threatening hypermetabolic state that occurs when susceptible patients are
exposed to volatile anesthetics or succinylcholine. Clinical presentation includes masseter muscle rigidity,
hypercarbia, ever, tachycardia, acidosis, and hyperkalemia. reatment: (1) discontinue trigger agents,
(2) oxygenate/ventilate, (3) dantrolene, (4) monitor and treat hyperkalemia, and (5) supportive care.

Name some o the physiologic changes that occur in the elderly population that must be considered
perioperatively?
Cardiovascular: decreased cardiac contractility and stroke volume.
GU: impaired ability to concentrate urine. Reduced creatinine unction (nl creatinine ≠ nl renal unction)
Respiratory: decreased response to hypoxia and hypercapnia, decreased vital lung capacity, and increased residual
volume.
Wound healing: longer rate o collagen turnover and reduced inf ammatory response.
TRAUMA AND CRITICAL CARE

What are the trauma zones o the neck?
Zone 1—clavicle to cricoid; explore i symptomatic or signi cant nding (workup: angio, bronch, EGD, and
swallow study).
Zone 2—cricoid to angle o mandible; explore all i penetrating platysma.
Zone 3—angle o mandible to skull base; explore i symptomatic or signi cant nding (workup: angio and
laryngoscopy).

What are common ractures rom an upright all?
Calcaneus, lumbar spine, and wrist/ orearm.