Operative Technique in Plastic Surgery – Kevin C.Chung

■ The depth of the nerve should guide the insertion site.
■ Insert the block needle in the plane of the ultrasound image, visualizing the
tip of the needle in real-time as the target is approached (TECH FIG 3).
■ Traverse the sartorius muscle to position the needle tip just lateral to the
femoral artery.
■ A “pop” may be felt as the needle passes through fascial layers.
TECH FIG 3 • Positioning and approach for
ultrasound-guided adductor canal block.
■ Take care to avoid the femoral vein, which often lies deep and lateral to the
artery, and may not be visible when pressure is applied to the ultrasound
transducer.
■ After careful aspiration, inject a small amount of local anesthetic.
■ Observe local anesthetic spread in the ultrasound image. This should
appear as hypoechoic fluid filling the space deep to sartorius and lateral to
femoral artery.
■ Ensure that local anesthetic is not tracking back along the sartorius muscle,
but rather staying contained in the adductor canal while partially
surrounding the femoral artery.
■ The needle should be advanced beyond the subsartorial fascia.
■ When the needle is positioned in close proximity to the nerve, and local
anesthetic spread is confirmed around the nerve, an additional 10 to 15 mL
of local anesthetic can be injected.
■ The adductor canal block can be used as an analgesic block or as a surgical
block in combination with sciatic block for surgery below the knee.

■ For a surgical block, use 15 to 20 mL of 1.5% mepivacaine, 2% lidocaine,
0.5% bupivacaine, or 0.5% ropivacaine.
■ For an analgesic block, use 10 to 15 mL of 0.25% bupivacaine or 0.25%
ropivacaine.
■ A catheter may be placed for continuous local anesthetic infusion.
■ Use 0.2% ropivacaine or 0.125% bupivacaine at 4 to 6 mL/h for
continuous infusion, with a patient-controlled bolus of 2 to 4 mL every 30
minutes.
■ Infusions are generally continued for 2 to 3 days following surgery.
PEARLS AND PITFALLS
Positioning
■ In obese patients, retracting and taping the abdominal pannus helps
optimize ultrasound imaging.
Sterility
■ For catheter placement, nerve blocks should be performed under
strict sterile conditions.
Paresthesias
■ Avoid needle-to-nerve contact if possible. Use hydrodissection to
achieve proper needle placement.
Vascular
puncture
■ The femoral and adductor canal blocks involve needle placement in
close proximity to vascular structures. To avoid vascular puncture,
always visualize the needle tip in the ultrasound image while
advancing.
Local
anesthetic
toxicity
■ Even with acceptable needle visualization, vascular puncture can
occur. Always aspirate before injection, inject slowly, and visualize
local anesthetic spread in the ultrasound image. Epinephrine may be
used at a low concentration (1:400 000) as a vascular marker. Do
not exceed the maximum safe dose of local anesthetics.
Catheter
placement
■ Once a catheter is placed, its position should be confirmed with
ultrasound imaging. Inject a small volume of local anesthetic
through the catheter to ensure appropriate spread around the nerve.
Dressing
■ Catheters should be secured with a clear occlusive dressing. An
anchoring device may be used as well and should be secured away
from the surgical field or tourniquet site.
Block
assessment
■ Quadriceps weakness is an early sign of successful femoral nerve
block. Femoral and adductor canal nerve blocks are reliably
assessed with testing the skin over the medial malleolus.

POSTOPERATIVE CARE
■ Following a nerve block procedure, patients should be monitored for at least
30 minutes for any signs of local anesthetic toxicity.
■ Patients should be contacted every day until the block wears off or the catheter
is removed.
■ Leakage from the catheter site is normal and expected but can be minimized
with the application of surgical glue at the insertion site.
■ Patients should be educated on expected weakness and fall risk.
■ Crutches and a knee immobilizer should be provided when appropriate.
■ Careful consideration should be given to using continuous femoral blocks for
outpatients.
■ Patients should be encouraged to use their systemic analgesics as needed.
■ Perioperative use of multimodal analgesia may include acetaminophen,
NSAIDs, and/or gabapentinoids around the clock to improve pain
management and decrease opioid usage.
■ Systemic analgesics should be initiated prior to the block wearing off.
■ Dressings should be left alone until the catheter is removed.
■ Dressing changes are not necessary and may increase the risk of infection or
catheter dislodgement.
OUTCOMES
■ Peripheral nerve blocks provide better pain control than traditional
medications; they reduce opioid consumption and its associated side effects.
■ Patient satisfaction is higher when peripheral nerve blocks are used for
perioperative pain control.
■ Pain management strategies that include a peripheral nerve block may reduce
the systemic inflammatory response and reduce persistent pain that is
associated with surgery.4
COMPLICATIONS
■ Peripheral nerve blocks have a low complication rate.
■ Short-term complications may include prolonged numbness, weakness, or
paresthesias.
■ Long-term numbness, weakness, or paresthesias are rare.
■ In a multicenter, international clinical registry of regional anesthetics, the all-
cause 60-day rate of neurological sequelae is 8.3/10 000.5

■ Local anesthetic systemic toxicity (LAST) is a rare but potentially deadly
complication.
■ A LAST protocol should be in place in institutions where nerve blocks are
performed.
• LAST checklist and resuscitation guidelines should be posted in the block
area
().
• Resuscitation medications (including Intralipid) and equipment should be
available in the block area.
• Access to cardiopulmonary bypass should be available in case of refractory
cardiovascular collapse.
REFERENCES
1. Kessler J, et al. Peripheral regional anaesthesia and outcome: lessons learned
from the last 10 years. Br J Anaesth. 2015;114(5):728-745.
2. Burckett-St Laurant D, et al. The nerves of the adductor canal and the
innervation of the knee: an anatomic study. Reg Anesth Pain Med.
2016;41(3):321-327.
3. Grevstad U, et al. The effect of local anesthetic volume within the adductor
canal on quadriceps femoris function evaluated by electromyography: a
randomized, observer- and subject-blinded, placebo-controlled study in
volunteers. Anesth Analg. 2016;123(2):493-500.
4. He Y, Li Z, Zuo YX. Nerve blockage attenuates postoperative inflammation in
hippocampus of young rat model with surgical trauma. Mediators Inflamm.
2015;2015:460125.
5. Sites BD, Barrington MJ, Davis M. Using an international clinical registry of
regional anesthesia to identify targets for quality improvement. Reg Anesth
Pain Med. 2014;39(6):487-495.

2
CHAPTERPopliteal Nerve Blocks
Ming Zhuo-Stine and Sarah J. Madison
DEFINITION
■ The popliteal nerve block targets the sciatic nerve in the popliteal fossa
proximal to its bifurcation into the common peroneal and tibial nerves.
■ It is a commonly used block for surgeries involving the lower leg, ankle, and
foot.
■ The nerve block can provide surgical anesthesia or postoperative analgesia.
The duration of the block varies based on the choice of local anesthetic and the
choice of single injection versus continuous catheter technique. For painful
surgeries, the continuous catheter technique can provide several days of
excellent postoperative pain control.1
■ The popliteal nerve block spares the medial aspect of the lower leg, an area
that is innervated by the saphenous nerve. A femoral or saphenous nerve block
must be performed in conjunction with a popliteal block for full sensory
blockade of the lower leg (FIG 1).

FIG 1 • Sensory distribution of the leg.
ANATOMY
■ The sciatic nerve consists of two distinct nerves, the tibial and common
peroneal nerves, which provide motor and sensory innervation to the majority
of the lower leg. The two nerves have their own epineurium and are encased in
an additional layer of connective tissue.2,3
■ Within the popliteal fossa, the branches of the sciatic nerve usually lie lateral
and posterior to the popliteal vessels. More proximally, the nerve can be found
between the biceps femoris, and semitendinosus and semimembranosus
tendons.
■ 2 to 10 cm proximal to the popliteal fossa crease, the sciatic nerve bifurcates
into the tibial and common peroneal nerves. The common peroneal nerve then

travels laterally around the head and neck of the fibula, whereas the large tibial
nerve continues caudally with the popliteal vessels.
■ The popliteal nerve block is often performed proximal to the point of
bifurcation or at the point of bifurcation, with injection of local anesthetic in or
around the common connective tissue sheath described by some as the
“paraneural sheath.”4,5
PATIENT HISTORY AND PHYSICAL FINDINGS
■ Assess patient’s pain history and proposed surgery to determine if a popliteal
nerve block is appropriate for the procedure.
■ Examine patient for preexisting neuropathy and weakness.
■ Assess for contraindications or increased risk of complications with regional
anesthesia:
■ Patient refusal
■ Allergy to local anesthetic
■ Infection at site of nerve block or systemic infection
■ Coagulopathy
■ Preexisting neuropathy
■ Increased risk of compartment syndrome
■ The patient’s surgeon and primary anesthesia team should agree with
placement of block.
■ Determine if a single injection nerve block or perineural catheter is indicated
depending on the requirements for surgical anesthesia and postoperative
analgesia. If a prolonged block is preferred for outpatient surgery, ensure that
the patient will be able to care for an insensate limb at home and can be
contacted for follow-up.
■ Prior to starting the nerve block, ensure that the patient will be able to proceed
with surgery and anesthesia (consents completed, appropriately NPO, etc.).
SURGICAL MANAGEMENT
Preoperative Planning
■ Patient preparation:
■ Surgical and anesthesia consents signed
■ Monitors—blood pressure cuff, ECG, pulse oximeter, capnography
■ Supplemental oxygen via nasal cannula or facemask
■ Pillows, blankets, or tables to aid positioning

■ Skin marker to mark the site laterality and surface landmarks
■ Sedation to optimize patient comfort—typically midazolam and fentanyl
■ Rescue drugs and emergency airway equipment available
■ Supplies for single injection technique:
■ Antiseptic skin disinfectant
■ Sterile gloves, mask, hat
■ Sterile drapes or towels
■ 50- to 100-mm 20- to 22-gauge short-bevel insulated stimulating needle
■ Small syringe and small gauge needle with lidocaine for skin infiltration
■ 30 mL local anesthetic of choice
■ Nerve stimulator and/or ultrasound machine with high-frequency linear
probe, sterile ultrasound probe cover, and ultrasound gel
■ Supplies for continuous catheter technique:
■ Antiseptic skin disinfectant
■ Sterile gloves, gown, mask, hat
■ Ultrasound machine with high-frequency linear probe or nerve stimulator
■ 30 mL local anesthetic of choice
■ Sterile regional anesthesia tray:
• Drapes or towels
• Gauze
• A 100-mm block needle, often a 17- or 18-gauge Tuohy needle
• A flexible nerve block catheter with connector (may use stimulating catheter
with nerve stimulator technique)
• 10- to 20-mL syringe
• Local anesthetic or saline for injection through needle
• Extension tubing
• Small syringe and small gauge needle with lidocaine for skin infiltration
• Surgical skin glue
• Transparent dressing
• Catheter stabilization device
• Ultrasound probe cover with ultrasound gel
Approach
■ Ultrasound-Guidance Versus Nerve Stimulation
■ Nerve localization can be achieved using peripheral nerve stimulators and/or

ultrasound guidance.
■ Over the past decade, ultrasound-guided nerve blocks have rapidly gained
popularity because they provide several advantages compared to the nerve
stimulator technique. The use of ultrasound provides direct, real-time
visualization of target nerves, needle advancement, and spread of local
anesthetic in the desired location.6 With continuous catheter techniques, the
precise location of the catheter tip can be visualized. Blood vessels and
smaller peripheral nerves can be identified and avoided. Research suggests
that ultrasound guidance provides an improvement in time required to
perform the block, block onset, and block success.7–10
■ For the popliteal sciatic block, ultrasound allows visualization of the precise
point where the sciatic nerve bifurcates, which is variable between patients.
Identifying this location is helpful in blocking both components of the sciatic
nerve.
■ For these reasons, although this chapter briefly covers nerve stimulator
approaches, the focus will be on ultrasound-guided techniques, which have
become routinely used in regional anesthesia.
■ Ultrasound in-plane versus out-of-plane needle insertion approaches
■ With the in-plane approach, the needle is inserted at the side of the
transducer, in line with the ultrasound beam (FIG 2). Because the needle is
within the plane of imaging, the entire needle shaft and tip should be seen as
echogenic line. In-plane approach is often used due to superior visualization
of the entire needle as it is advanced toward the target.
■ With the out-of-plane approach, the needle is introduced perpendicular to the
transducer (FIG 3). The needle crosses the plane of the ultrasound beam such
that the needle shaft and tip are seen as an echogenic dot on ultrasound.
Needle tip localization is more difficult with this approach. Techniques to
help locate the needle tip include looking for tissue displacement, scanning
for the needle tip, and injection of fluid to separate tissue planes
(hydrodissection). One advantage of using the out-of-plane approach is that
the needle traverses only skin and adipose tissue, avoiding muscle.
■ Approaches related to patient positioning
■ A wide range of positions can be used during popliteal sciatic nerve
blockade. Each is discussed and illustrated in further detail in the following
section.
■ Choice of positioning is typically dictated by a combination of patient
comfort, patient mobility, operator ergonomics, and the operator’s personal

preference. Body habitus, pain, or the presence of external fixation devices
may limit the ability of the patient to assume a lateral or prone position.
■ Patients may be positioned supine or prone for nerve stimulator techniques.
■ Patients may be positioned supine, lateral, or prone for ultrasound-guided
nerve blocks. Regardless of the position, the ultrasound image is identical. If
the out-of-plane needle insertion approach is desired, prone or lateral
positioning provides better access.
FIG 2 • In-plane approach to popliteal sciatic nerve
block.
FIG 3 • Out-of-plane approach to popliteal sciatic nerve
block.
T E C H N I Q U E S

■ Nerve Stimulator, Lateral Approach
■ The patient is positioned supine with leg slightly elevated to visualize foot
movement. This is best achieved by placing the leg on a small stack of
blankets such that the foot and heel protrude beyond the blankets.
■ Main landmarks are the popliteal fossa crease and the muscular groove
between the biceps femoris and vastus lateralis muscles. The site of needle
insertion is within the muscular groove, about 7 to 8 cm cephalad to the
popliteal crease; the muscular groove may be accentuated by having the
patient lift their leg off of the plane of the table. Use a skin marker to denote
landmarks.
■ Prepare the skin with an antiseptic solution and infiltrate the proposed needle
insertion point with local anesthetic via a small gauge needle. Connect the
peripheral nerve stimulator to a 100-mm 20- to 22-gauge short-bevel
insulated stimulating needle. Using sterile technique, insert the needle
perpendicular to the skin and advance in a horizontal plane between the
vastus lateralis and biceps femoris muscles until femur is contacted; bony
contact provides a reference point for nerve localization. The sciatic nerve is
typically 1 to 2 cm beyond the skin-to-femur distance and located posterior to
the femur (TECH FIG 1).
■ With the nerve stimulator set to 1.5 mA, withdraw needle almost to the skin
and redirect at a 30-degree angle posteriorly until foot twitch is seen,
typically at a depth of 5 to 7 cm. Stimulation of the common peroneal nerve
causes dorsiflexion and foot eversion. Stimulation of the tibial nerve, which
is more medial, results in plantar flexion and foot inversion. Tibial
stimulation is preferred because it may result in a higher rate of complete
sciatic nerve block.11 Local twitches of the biceps femoris muscle or vastus
lateralis muscle indicates that the needle is located too superficial or anterior,
respectively.
■ If a motor response is not elicited, withdraw needle to skin and redirect 5 to
10 degrees more posterior.
■ Once sciatic nerve stimulation is obtained, make small needle adjustments
until twitches are obtained at 0.3 to 0.5 mA.
■ Check for intravascular placement with gentle aspiration and then slowly
inject 30 to 40 mL of local anesthetic.

TECH FIG 1 • Cross-sectional anatomy of the distal
thigh (right leg 8 cm above knee).
■ Nerve Stimulator, Posterior Approach
■ Position the patient prone with the leg to be blocked protruding from the end
of the bed or slightly elevated on a blanket to allow for visualization of foot
movement.
■ Primary landmarks are the popliteal fossa crease, tendon of the biceps
femoris laterally, and tendons of the semitendinosus and semimembranosus
muscles medially. Knee flexion against resistance can help accentuate the
tendons and identify the knee crease. The needle insertion point is about 7 cm
above the popliteal fossa crease 1 cm lateral and 1 cm caudal to the apex of
the popliteal fossa. Use a skin marker to denote landmarks (TECH FIG 2).
■ Prepare the skin with an antiseptic solution and infiltrate the proposed needle
insertion point with local anesthetic via a small-gauge needle. Connect the

peripheral nerve stimulator set at 1.5 mA to a 50-mm 20- to 22-gauge short-
bevel insulated stimulating needle.
■ Using sterile technique, insert the needle 45 to 60 degrees to the skin, then
advance the needle until foot twitches are obtained. Typical depth is 3 to 5
cm from the skin. Stimulation of the common peroneal nerve causes
dorsiflexion and foot eversion. Stimulation of the tibial nerve, which is more
medial, results in plantar flexion and foot inversion. Tibial stimulation is
preferred because it may result in a higher rate of complete sciatic nerve
block.11
■ If a motor response is not elicited, withdraw the needle to the skin and
redirect 5 to 15 degrees laterally. If there is continued difficulty localizing the
sciatic nerve, withdraw needle to skin and reinsert 1 cm laterally in
incremental steps.
■ Once sciatic nerve stimulation is obtained, make small adjustments to the
needle position to obtain foot twitches at 0.3 to 0.5 mA.
■ Check for intravascular placement with gentle aspiration, and then slowly
inject 30 to 40 mL of local anesthetic.
TECH FIG 2 • Positioning and landmarks for
stimulator-guided popliteal block.
■ Nerve Stimulator, Continuous Catheter Technique
■ Use the same procedure as for single injection nerve stimulator technique
described above, but with a larger insulated stimulating Tuohy needle to
allow for passage of a catheter. An in situ catheter allows for continued

dosing of local anesthetic to provide prolonged anesthesia and analgesia.
Either a stimulating or nonstimulating catheter can be used:
■ Nonstimulating catheter:
• After localizing the sciatic nerve with motor response at 0.3 to 0.5 mA,
inject local anesthetic to open up space for the catheter.
• Insert a catheter through the Tuohy needle and advance 3 cm past the tip
of the needle. If catheter insertion is difficult, slight adjustment of the
needle or direction may facilitate catheter advancement.
• Carefully withdraw needle while simultaneously advancing the catheter.
Aspirate the catheter to check for inadvertent intravascular placement and
secure using a catheter stabilization device and clear dressing.
■ Stimulating catheter:
• Localize the sciatic nerve with a motor response around 0.5 mA. Do not
inject local anesthetic or saline through the needle or the motor response
will be lost. D5W can be used if necessary.
• Insert a stimulating catheter with the nerve stimulator now attached to the
catheter. Advance the catheter 3 to 5 cm past the needle tip while
maintaining a motor response. If motor response is lost, withdraw and
readvance the catheter. If catheter insertion is difficult, withdraw the
catheter and adjust the needle slightly to facilitate catheter advancement.
• Once the catheter is in a satisfactory position, the needle can then be
carefully withdrawn while advancing the catheter simultaneously. Feed
additional catheter under the skin to minimize premature dislodgment.
Aspirate the catheter to check for inadvertent intravascular placement and
secure.
■ Ultrasound-Guided, In-Plane Needle Insertion
Approach
■ Of the various approaches described, this is the most commonly used
approach due to ease of needle and target visualization.
■ Positioning—Patients may be positioned supine, lateral decubitus, or prone
(TECH FIG 3). Regardless of the position selected, ultrasound imaging and
needling are similar. Thus, patient positioning is determined by a
combination of patient comfort, patient mobility, and operator ergonomics
and preference.

■ Supine position
• Position the patient supine with the operative leg elevated using blankets,
pillows, or a table to accommodate an ultrasound probe beneath the thigh.
• The operator is positioned on the side to be blocked with the ultrasound
screen on the opposite side of the patient.
■ Lateral decubitus position
• Position patient lateral with the procedural leg on top, knee extended. The
dependent leg can be bent at the knee to enhance stability.
• Operators may choose to stand in front of the patient, facing the anterior
thigh with the ultrasound probe directed toward themselves or stand
behind the patient, facing the posterior aspect of the thigh, pointing the
probe away from themselves.
■ Prone position
• Position the patient prone with the operative leg slightly abducted. A
blanket folded under the lower leg may help relax the hamstring tendons
to facilitate ultrasound transducer placement.
• The operator is positioned on the side to be blocked with the ultrasound
screen on the opposite side of the patient.
■ Imaging
■ Disinfect the skin with an antiseptic solution, drape the procedural area,
and cover the ultrasound probe with a sterile ultrasound sheath and gel.
■ Place the transducer in a transverse orientation in the popliteal fossa to
obtain a short-axis view of the nerves.
■ Perform a systematic survey of the surrounding structures. Identify the
femur. The pulsatile popliteal artery and the accompanying vein are located
posterior to the femur. The sciatic nerve appears as a hyperechoic oval
structure with a honeycomb pattern that is posterior and lateral to the artery,
medial to the biceps femoris muscle, and lateral to the semitendinosus and
semimembranosus muscles.
■ Optimize the ultrasound image by adjusting variables especially frequency,
gain, depth, and focal zones. Tilting the ultrasound transducer to direct the
beam caudally may enhance the visualization of the nerve by bringing the
ultrasound plane more perpendicular to the nerve.
■ Scan proximally and distally along the sciatic nerve to identify the
bifurcation point of the common peroneal and tibial nerves. This division
usually occurs 2 to 7 cm proximal to the popliteal crease and at a depth of 2

to 4 cm.
■ Choose a location just proximal to the bifurcation, where the peroneal and
tibial nerves are still enclosed in a common connective tissue sheath
(TECH FIG 4).
■ Needling
■ Determine the optimal needle path. Identify small vessels that should be
avoided. The needle insertion point will be near the lateral aspect of the
transducer.
• Choose an insertion point lateral to the transducer. The needle will
traverse the biceps femoris muscle.
• Choose an insertion point close to the transducer to decrease the amount
of muscle tissue along the needle path.
■ Infiltrate the skin with local anesthetic at the insertion site. Use a 20- to 22-
gauge 100-mm block needle. Flush the tubing and syringe to remove air
since air will obscure the ultrasound image.
■ Introduce the block needle in the same plane as the ultrasound beam with
the bevel of the needle facing the probe. The needle shaft and tip should
always be visualized during needle advancement.
■ Carefully advance needle under direct visualization toward the nerve
sheath, taking care to bring the needle close to the edge of the nerve, to
avoid puncturing the nerve.
■ Aspirate, then inject 1 to 2 mL of local anesthetic. Never inject or advance
needle if patient complains of pain or if high pressure (greater than 15 psi)
is met on injection or if the nerve is swelling. These signs dictate an
immediate repositioning of the needle tip.
■ If in the correct location, the hypoechoic fluid should surround the nerve
completely.
■ If fluid spread is not ideal, reposition needle to achieve adequate
circumferential spread with a total of 20 to 30 cc local anesthetic.

TECH FIG 3 • Supine, lateral decubitus (A), and prone
positioning (B) for in-plane ultrasound-guided popliteal
block.
TECH FIG 4 • Ultrasound image of the sciatic nerve at
its bifurcation. T, tibial nerve; CP, common peroneal
nerve.
■ Ultrasound-Guided, Out-of-Plane Needle Insertion
Approach
■ Needle localization is more difficult with an out-of-plane approach in
comparison to an in-plane approach. Because the needle crosses the plane of
the ultrasound beam, the needle shaft and tip are seen only as an echogenic
dot. The advantage is that the needle traverses only skin and adipose tissue,
avoiding muscle.
■ Positioning—Patients may be positioned lateral decubitus or prone for out-

of-plane needling. Regardless of the position selected, ultrasound imaging
and needling are identical. Choose the best position based on patient comfort
and operator preference.
■ Imaging
■ Disinfect and prepare the site as described above.
■ Place the transducer in the transverse orientation in the popliteal fossa to
obtain a short-axis view of the sciatic nerve.
■ Follow the same steps for imaging as with the in-plane ultrasound
approach.
■ Needling
■ Align the sciatic nerve in the center of the ultrasound screen and place a
wheal of local anesthetic in the center of the probe, close to the probe.
■ Insert a block needle through the skin wheal directed approximately 60 to
80 degrees cephalad. Aim to place the needle tip to the side of the nerve to
avoid nerve trauma.
■ As the needle crosses the plane of the ultrasound beam, it will appear in
cross-section as an echogenic dot. Because both the needle shaft and tip
have a similar appearance, track the tip with the probe as the needle is
advanced. If not directly visualized, the needle tip may be inferred by tissue
displacement along the needle path as well as hydrolocation.
■ Aspirate, and then slowly inject local anesthetic while observing the fluid
spread. Ideally, hypoechoic fluid should be seen spreading
circumferentially around the hyperechoic nerve. Inject 20 to 30 mL of local
anesthetic.
■ Ultrasound-Guided Continuous Catheter
Technique
■ Catheter placement provides a continuous infusion or additional boluses of
local anesthetic to provide prolonged anesthesia or pain control.
■ Strict aseptic technique is crucial for prevention of infectious complications.
■ Both in-plane and out-of-plane ultrasound-guided approaches can be
utilized.
■ Catheter placement utilizes the same needle placement procedure as
described above but requires a larger needle for passage of a perineural
catheter. After the needle is confirmed to be the correct location, an

additional 5 to 10 mL bolus of saline or local anesthetic solution is injected to
facilitate catheter advancement.
■ Carefully advance the catheter about 3 to 5 cm past the needle tip. If catheter
insertion is difficult, withdraw the catheter and try small adjustments of the
needle. Before or after needle removal, confirm catheter tip location with
injection through the catheter, watching for appropriate spread.
■ Carefully withdraw the needle while simultaneously advancing the catheter
in different tissues. Overfeeding additional catheter under the skin may help
prevent accidental dislodgment.
■ Carefully secure the catheter in place with an anchoring device and clear
dressing. Use a total of 20 to 30 mL of local anesthetic.
PEARLS AND PITFALLS
Identification
of nerve and
structures
■ Knowledge of both surface anatomy and ultrasound anatomy is
essential.
■ Tilt the transducer beam caudally toward the foot to direct
ultrasound waves perpendicular to the nerve and enhance
visualization.
■ Asking the patient to plantar flex and extend their foot causes the
tibial and common peroneal nerves to slide against each other,
known as the “seesaw sign.”12
■ At the popliteal crease, the vessels are immediately anterior to the
tibial nerve. Reduce transducer pressure to visualize the popliteal
vein. Trace the nerve proximally to where the common peroneal
joins to form the sciatic nerve.
Nerve block
coverage
■ In combination with a saphenous nerve block, popliteal block
provides complete sensory blockade below the knee.
■ Popliteal block does not cover thigh tourniquet pain. The patient
may require general anesthesia or a femoral nerve block instead of a
selected saphenous when a thigh tourniquet is used.
Approach
■ Ultrasound imaging allows for various patient positions and needle
approaches. Choice of approach depends on patient and operator
comfort.
Catheter
placement
■ For a continuous technique, once the needle is in optimal position,
inject a small amount of saline or local anesthetic to facilitate

catheter advancement.
■ Check the catheter tip location by injecting a small volume of
saline or local anesthetic with ultrasound visualization.
■ Feed additional catheter in the muscle or subcutaneous tissue to
prevent inadvertent catheter dislodgment.
Postblock
safety
■ Always counsel patients on fall risk and injury risk to a numb
extremity. Providing a boot will improve stability. Patients must not
weight bear until the block has fully resolved.
■ Both thorough preoperative counseling and clarification of patient
expectations are essential to the successful management of the
block.
POSTOPERATIVE CARE
■ Block onset time varies dramatically from 10 to 45 minutes depending on
patient, medication selection, and proximity of the injectate to the nerve.
■ Thorough patient education is essential for the successful function and safety
of the nerve block.
■ All patients should be followed postoperatively for block resolution and to
detect complications.
■ All patients with nerve block catheters should be evaluated daily while in the
hospital or contacted by phone if receiving nerve block infusion at home.
■ Catheter leakage at the site of insertion and catheter dislodgment may occur.
Patients should have additional analgesics available for breakthrough pain or in
the event of catheter dislodgment.
COMPLICATIONS
■ Injuries as a result of an insensate limb—Instruct patient, nurses, and
caregivers on proper care of an insensate extremity including fall precautions
and positioning. Avoid nerve blocks in patients who have a high risk of
compartment syndrome.
■ Infection—Use strict aseptic technique, avoid perineural catheter placement in
patients with active infections, and limit duration of perineural catheter use.
■ Hematoma formation—Ultrasound imaging and avoidance of vascular trauma
or multiple needle passes may minimize risk.
■ Nerve injury—Rare complication from direct needle trauma or intraneural
injection; usually resolves in weeks to months. Risk may be increased in
patients with preexisting nerve injury. More common causes of nerve injury

include surgical, ischemic, and compressive nerve injuries. Avoid tourniquet
placement over nerve block site to decrease ischemic nerve injury. Avoid
needle advancement or injection if the patient complains of pain or paresthesias
or if increased pressure (greater than 15 psi) is felt during injection. Avoid
needle advancement during an ultrasound-guided procedure if the target or
needle tip is poorly visualized.
■ Local anesthetic toxicity—Avoid intravascular injection by aspirating prior to
injection and aspirating frequently during injection. Patients should be
monitored following the nerve block. Have rescue medications, such as lipid
emulsion, and emergency airway equipment readily available.
REFERENCES
1. Singelyn FJ, Aye F, Gouverneur JM. Continuous popliteal sciatic nerve block:
an original technique to provide postoperative analgesia after foot surgery.
Anesth Analg. 1997;84(2):383-386.
2. Andersen HL, Andersen SL, Tranum-Jensen J. Injection inside the paraneural
sheath of the sciatic nerve: direct comparison among ultrasound imaging,
macroscopic anatomy, and histologic analysis. Reg Anesth Pain Med.
2012;37(4):410-414.
3. Franco CD. Connective tissues associated with peripheral nerves. Reg Anesth
Pain Med. 2012;37(4):363-365.
4. Perlas A, et al. Ultrasound-guided popliteal block through a common
paraneural sheath versus conventional injection: a prospective, randomized,
double-blind study. Reg Anesth Pain Med. 2013;38(3):218-225.
5. Karmakar MK, et al. High-definition ultrasound imaging defines the
paraneural sheath and the fascial compartments surrounding the sciatic nerve at
the popliteal fossa. Reg Anesth Pain Med. 2013;38(5):447-451.
6. Sinha A, Chan VW. Ultrasound imaging for popliteal sciatic nerve block. Reg
Anesth Pain Med. 2004;29(2):130-134.
7. Liu SS. Evidence basis for ultrasound-guided block characteristics onset,
quality, and duration. Reg Anesth Pain Med. 2016;41(2):205-220.
8. Salinas FV. Evidence basis for ultrasound guidance for lower-extremity
peripheral nerve block: update 2016. Reg Anesth Pain Med. 2016;41(2):261-
274.
9. Perlas A, et al. Ultrasound guidance improves the success of sciatic nerve
block at the popliteal fossa. Reg Anesth Pain Med. 2008;33(3):259-265.
10. Abrahams MS, et al. Ultrasound guidance compared with electrical

neurostimulation for peripheral nerve block: a systematic review and meta-
analysis of randomized controlled trials. Br J Anaesth. 2009;102(3):408-417.
11. Taboada Muniz M, et al. Lateral approach to the sciatic nerve block in the
popliteal fossa: correlation between evoked motor response and sensory block.
Reg Anesth Pain Med. 2003;28(5):450-455.
12. Schafhalter-Zoppoth I, et al. The “seesaw” sign: improved sonographic
identification of the sciatic nerve. Anesthesiology. 2004;101(3):808-809.

3
CHAPTERAnkle Block
Andrew Lyons and Fred Mihm
DEFINITION
■ Ankle block is a highly effective peripheral nerve block that results in
anesthesia of the entire foot. This block has been shown to reduce both
postoperative pain and opioid consumption following foot surgery.1,2
■ Though a number of injections are required, a low total volume of local
anesthetic injectate is required to successfully perform an ankle block.
■ The ankle block can be useful due to its relatively low-risk profile, technical
ease, and efficacy.
■ Typical plastic surgery procedures that utilize this block include tendon repair
and distal foot or toe amputation.
ANATOMY
■ An ankle block is the selective blockade of both the saphenous nerve and the
four terminal branches—deep and superficial peroneal, tibial, and sural nerves
—of the sciatic nerve.
■ Ankle block is considered to be an easy block to perform because the terminal
nerves of interest are generally superficial and are reliably located next to
readily identifiable surface landmarks.
POSITIONING AND PREPARATION
■ Ankle block is most commonly performed with the patient in the supine
position.
■ Elevation of the foot by bolstering the calf with a pillow will facilitate access
to the ankle (FIG 1).
■ It is helpful to have an assistant available to gently place the leg in either

internal or external rotation.
MATERIALS
■ Topical disinfectant (chlorhexidine, betadine, or equivalent)
■ Sterile gloves
■ Ultrasound with a small, high-frequency linear probe
■ 20-mL sterile syringe
■ 22-gauge short-bevel block needle
■ Non-epinephrine containing local anesthetic
GENERAL CONSIDERATIONS
■ The goal of the ankle block is to deliver local anesthetic adjacent to the five
nerves that innervate the foot.
■ Needle insertion can be either in-plane or out-of-plane for each of the terminal
nerve blocks that comprise an ankle block.
■ 3 to 5 mL of local anesthetic per nerve is required for a successful block.
■ The tibial nerve should be addressed before blocking the other nerves because
of its relatively larger size and resultant resistance to the effects of local
anesthetics.
■ The use of ultrasound guidance augments the clinical efficacy of an ankle
block, especially for the tibial and deep peroneal nerves, which are relatively
deep.3–6
■ A small high-frequency linear ultrasound transducer is recommended.
FIG 1 • Proper positioning of the foot is essential when
performing an ankle block. The patient is placed supine

and a pillow is used to facilitate access to the ankle.
T E C H N I Q U E S
■ Tibial Nerve
■ Landmark technique: Inject 3 to 5 mL of local anesthetic in the deep tissue
of the ankle posterior to the medial malleolus and the posterior tibial artery.
The injection is typically performed after the needle contacts the underlying
bone (tibia) and is withdrawn 0.5 to 1 cm.
■ Unlike the other nerve blocks that comprise an ankle block, a nerve
stimulator can be used as an adjunct for nerve block; plantar flexion of the
toes indicates proper needle placement with tibial nerve stimulation.
■ Ultrasound-guided technique: Place the ultrasound probe horizontally just
superior and posterior to the medial malleolus to visualize the tibial nerve
(TECH FIG 1A).
■ The tibial nerve is superficial to both the belly and the tendon of the flexor
hallucis longus.
■ The tibial nerve lies immediately posterior to the posterior tibial vessels of
the ankle; at this level, the nerve and vessels may be easily mistaken for
one another. Sometimes, a fascia separates the nerve from the vessels,
placing the nerve deeper and partially behind the vessels (TECH FIG 1B).
■ Color Doppler imaging may be helpful in distinguishing the posterior tibial
artery from surrounding structures.
TECH FIG 1 • A. Tibial nerve block is performed by
injecting local anesthetic into the deep tissue of the

ankle. B. Ultrasound image of a tibial nerve block
demonstrating the nerve (TN) in the deep tissue of the
ankle just posterior to the vascular complex formed by
both the posterior tibial artery (pTA) and the posterior
tibial vein (pTV). Note the flexor hallucis longus (FHL)
is found deep to the nerve. The Achilles tendon (AT)
serves as the most posterior boundary of the image.
■ Deep Peroneal Nerve
■ Landmark technique: Identify the extensor hallucis longus tendon and the
dorsalis pedis pulse on the dorsal aspect of the ankle. Insert the block needle
between these two landmarks perpendicular to the skin and inject 3 to 5 mL
of local anesthetic into the deep tissue.
■ Ultrasound-guided technique: Place the ultrasound probe in a transverse
orientation over the anterior foot just above the line joining the malleoli
(TECH FIG 2A) to visualize the deep peroneal nerve adjacent to the dorsalis
pedis artery (TEHC FIG 2B).
TECH FIG 2 • A. Deep peroneal nerve block is
performed by injecting local anesthetic into the deep
tissue of the anterior ankle. B. Ultrasound image of a
deep peroneal nerve block demonstrating the deep
peroneal nerve (DPN) located lateral to the distal-most
branch of anterior tibial artery (ATA), also known as
the dorsalis pedis artery. Branching of the anterior
tibial vein (ATV) is common at this location.

■ Superficial Peroneal Nerve
■ Landmark technique: Identify the line between the injection point for the
deep peroneal nerve block and the lateral malleolus. Inject 3 to 5 mL
subcutaneously along this line.
■ Ultrasound-guided technique: Place the ultrasound probe in a transverse
orientation just lateral to the deep peroneal nerve (TECH FIG 3A) to allow
for visualization of the superficial peroneal nerve (TECH FIG 3B).
TECH FIG 3 • A. Superficial peroneal nerve block is
performed by injecting local anesthetic into the
subcutaneous tissue of the ankle just lateral to the
location of deep peroneal nerve block. B. Ultrasound
image of a superficial peroneal nerve block
demonstrating the superficial peroneal nerve (SPN) in
the subcutaneous tissue along the line between the
location of the deep peroneal nerve and the lateral
malleolus. This nerve is sometimes difficult to
visualize using an ultrasound.
■ Sural Nerve
■ Landmark technique: Inject 3 to 5 mL of local anesthetic in the subcutaneous
plane along the line formed between the lateral malleolus and the Achilles
tendon.
■ Ultrasound-guided technique: Place the ultrasound probe just posterior to the
lateral malleolus to visualize the sural nerve (TECH FIG 4A).
■ The sural nerve lies adjacent to the short saphenous vein in the groove
between the Achilles tendon and the peroneus brevis muscle (TECH FIG

4B).
TECH FIG 4 • A. Sural nerve block is performed by
injecting local anesthetic into the subcutaneous tissue
of the groove between the lateral malleolus and the
Achilles tendon. A calf tourniquet may facilitate the
ultrasound imaging of this block by enlarging the short
saphenous vein. B. Ultrasound image of a sural nerve
block demonstrating the sural nerve (SN) in the
groove between the Achilles tendon (AT) and the
peroneus brevis (PB) muscle. The short saphenous
vein (SSV) is anterior to the sural nerve.
■ Saphenous Nerve
■ Landmark technique: Inject 3 to 5 mL of local anesthetic in the superficial
tissue of the ankle 1 cm anterior to the medial malleolus.
■ Ultrasound-guided technique: Place the ultrasound probe in a transverse
orientation, just anterior to the medial malleolus (TECH FIG 5A) to
visualize the saphenous nerve traveling lateral to the great saphenous vein
(TECH FIG 5B).

TECH FIG 5 • A. Saphenous nerve block is performed
by injecting local anesthetic into the subcutaneous
tissue of the ankle just anterior to the medial
malleolus. A calf tourniquet may facilitate the
ultrasound imaging of this block by enlarging the great
saphenous vein. B. Ultrasound image of a saphenous
nerve block demonstrating the saphenous nerve (SN)
just posterior to the great saphenous vein (GSV).
■ Complications
■ Multiple injections about the ankle may result in significant patient
discomfort. IV sedation can be used to enhance patient comfort during the
procedure.
■ Intravascular injection is uncommon and the risk for local anesthetic toxicity
is low, as small volumes of local anesthetic are generally used. The absence
of epinephrine from the local anesthetic solution eliminates the risk of
intravenous epinephrine toxicity and reduces risk of ischemia of the
anesthetized foot.
■ Induration of the superficial tissues around injection sites is not uncommon.
■ Ankle hematoma as a result of vascular injury may also occur, but is usually
self-limited.
REFERENCES
1. Tryba M. Ankle block: a safe and simple technique for foot surgery. Curr
Opin Anaesthesiol. 1997;10(5):361-365.
2. Vadivelu N, et al. Role of regional anesthesia in foot and ankle surgery. Foot
Ankle Spec. 2015;8(3):212-219.
3. Chin KJ, et al. Ultrasound-guided versus anatomic landmark-guided ankle
blocks: a 6-year retrospective review. Reg Anesth Pain Med. 2011;36(6):611-
618.
4. Fredrickson MJ. Ultrasound-guided ankle block. Anaesth Intensive Care.
2009;37(1):143-144.
5. Redborg KE, et al. Ultrasound improves the success rate of a tibial nerve
block at the ankle. Reg Anesth Pain Med. 2009;34(3): 256-260.

6. Redborg KE, et al. Ultrasound improves the success rate of a sural nerve block
at the ankle. Reg Anesth Pain Med. 2009;34(1):24-28.

4
CHAPTEREpidural Anesthesia
Rachel C. Steckelberg, Jean-Louis Horn, and Sarah Madison
DEFINITION
■ Neuraxial anesthesia is a type of regional anesthesia technique in which
anesthesia medication is injected into the tissue surrounding the nerve roots as
they exit the spine (eg, epidural anesthesia) and/or directly into the
cerebrospinal fluid (eg, spinal anesthesia or subarachnoid anesthesia).
■ Continuous epidural anesthesia is a neuraxial anesthetic technique that may be
used for postoperative analgesia, surgical anesthesia, and obstetric analgesia.
■ Epidural anesthesia may be used to provide anesthesia at any level below the
chin, either alone or in combination with general anesthesia.
■ Epidural anesthesia may be administered as a single injection or as a
continuous infusion via a catheter.
■ The location of the epidural placement determines the distribution of
analgesia. An epidural block may be performed at the cervical, thoracic,
lumbar, or sacral (eg, caudal) levels.
■ A continuous infusion of local anesthesia and/or opioid pain medication may
provide postoperative pain control for several days after surgery.
■ Motor block with an epidural may range from none to complete, depending on
the choice of drug, concentration, dosage, and/or level of administration.
■ Epidural analgesia is often part of a multimodal regimen that also includes
systemic medications.
ANATOMY
■ The epidural space surrounds the spinal meninges (eg, dura mater) and the
spinal nerve roots as they course outward to become peripheral nerves. It also
contains venous plexuses, lymphatics, and fat tissue.

■ Knowledge of surface anatomy landmarks is essential for safe and reliable
epidural placement (Table 1).
■ In the cervical area, the most prominent spinous process is usually C7.
■ The inferior angle of the scapula can be used to estimate the level of the T7
spinous process with the arms located at the side.
■ The spinal cord terminates at level L1 in adults. The dural sac terminates at
S2.
■ The body of L4 and/or the interspace between L4 and L5 spinous processes
typically can be found by drawing a line between the highest points of both
the iliac crests (Tuffier line).
■ The line connecting the posterior superior iliac spine (PSIS) crosses at the
level of the S2 posterior foramina.
■ The sacral hiatus is located by palpating for a depression (eg, the sacral
hiatus) just above or between the gluteal clefts and above the coccyx. This is
the point of entry for caudal epidural blocks.
■ By counting up or down from these surface anatomy reference points, other
spinal levels can be identified.
■ Epidural anesthesia may be performed at any level of the spinal cord.
However, each epidural location (cervical, thoracic, and lumbar) has unique
anatomic features (Table 2).
■ The angle of the spinous processes become progressively less angled closest to
the base of the spine. For example, the spinous processes of the cervical and
lumbar spine are more horizontal than the spinous processes in the thoracic
spine, which are typically slanted in a more caudad direction and can overlap
significantly. Thus, the technique for placement of the epidural needle varies
considerably depending on the level selected.
■ The ideal location of epidural placement is at the same dermatome of the
surgical incision.
Table 1 Anatomic Landmarks for Identifying Vertebral Levels for Epidural
Injection
Anatomic Landmark
Features
C7
Vertebral prominence (most prominent spinous
process in neck)
T3
Root of spine of scapula
T7
Inferior angle of scapula

L4
Line between iliac crests
S2
Line between posterior inferior iliac spines
Sacral hiatus
Depression or groove above or between
gluteal clefts directly above the coccyx
Table 2 Anatomic Features of Cervical, Thoracic, and Lumbar Spine
Regions
Anatomic Feature Cervical
Thoracic
Lumbar
Size
Small
Larger
Largest
Spinous process
Slender, often
bifid (C2-C6)
Long and thick,
project inferiorly
Short and blunt,
project posteriorly
Transverse
process
Small
Large
Large and blunt
Size of
intervertebral
discs
Thick (compared
to vertebral
bodies)
Thin (compared
to vertebral
bodies)
Very large
PATIENT HISTORY AND PHYSICAL FINDINGS
■ A preoperative history and physical must be performed prior to epidural
placement. Particular attention should be paid to anesthetic history, preexisting
neuropathies, history of bleeding diatheses, medication history (especially any
use of blood thinning medications), medication allergies, a history of prior
neuraxial anesthesia and/or spine surgery (including spinal fusion surgery), and
any history of spine disorders (including spina bifida and/or scoliosis). If
imaging of the spine is available and would be useful for epidural placement, it
should be reviewed.
■ Physical exam should pay particular attention to any localized infections,
masses, or other irregularities at the site of the planned epidural placement or
surrounding areas.
■ Contraindications to epidural anesthesia include patient refusal, bleeding
disorders, severe hypovolemia, elevated intracranial pressure, infection at the
site of epidural needle placement, flow-limiting cardiac lesions such as mitral
or aortic valve stenosis, and local spinal pathology.
IMAGING

■ When available, previous imaging of the spine should be reviewed, but routine
imaging is not typically required prior to epidural placement.
■ Preinsertion ultrasound will assist in accurate identification of the vertebral
level of interest, the midline, and the depth of the epidural space (FIG 1).1–3
NONOPERATIVE MANAGEMENT
■ The balance of risks and benefits must be considered for every interventional
technique, including epidural anesthesia. Depending on a number of factors
(including patient history, anatomy, surgery type, etc.), it may be more
appropriate to employ alternative methods of analgesia, including peripheral
nerve blocks and/or systemic medications for pain control.
■ Careful attention must be paid to the maximum dose of additional opioid or
other local anesthetic medications used for pain control when an epidural is in
place.
■ Nonopioid pain medications can also be useful adjuncts to epidural
anesthesia/analgesia.
SURGICAL MANAGEMENT
■ Epidural anesthesia is indicated for postoperative analgesia of any surgical
procedure below the level of the neck.
■ Thoracic epidurals are rarely used for primary surgical anesthesia, but more
commonly for intraoperative and postoperative analgesia.
■ Single injection or catheter techniques are useful for chronic pain
management.
■ Infusions via an epidural catheter are helpful in providing prolonged analgesia
and may enhance postoperative ventilation in patients with underlying lung
pathology following thoracic or chest wall surgery.
■ Local anesthetic via epidural administration will block sympathetic, sensory,
and motor nerves. The effects are dependent on the volume, concentration, and
type of medication administered via the epidural.

FIG 1 • Ultrasound of the lumbar and thoracic spine for
epidural placement.
Preoperative Planning
■ Surgical site, extent of incision, anticipated degree of postoperative pain,
and/or any preexisting conditions (bleeding disorders, preexisting neuropathies,
etc.) that may increase the risk of complications should be discussed among the
care team prior to epidural placement.
■ If an epidural anesthetic is under consideration, the risks and benefits should
be discussed with the patient. The patient must be informed and prepared for
neuraxial anesthesia and the epidural must be an appropriate anesthetic
technique for the type of surgery.
■ Epidural anesthesia is rarely considered an appropriate mode of analgesia for
outpatient procedures.
■ Neuraxial anesthetic techniques, such as epidural anesthesia, should only be
performed in facilities that have the equipment and drugs needed for
intubation, resuscitation, and general anesthesia available.
Positioning
■ The most common patient positions for epidural placement are sitting and
lateral.
■ In very obese patients, it may be easier to appreciate the anatomic midline with
the patient in the upright (eg, sitting) position.
■ In the sitting position, the patient should rest the elbows on his or her thighs or
a table, or should hug a pillow. The bed should be flat and the patient’s hips
level to the bed.
■ The patient should be instructed to arch his/her back to provide spinal flexion.

■ Arching the back like a “mad cat” maximizes the area between the adjacent
spinous processes and brings the spine closer to the skin surface (FIG 2A).
■ Alternatively, the lateral decubitus position may be considered for epidural
placement. In this position, the patient lies on his or her side with knees flexed
into the chest and pulled high, assuming the “fetal” position (FIG 2B). An
assistant should help the patient hold this position.
Approach for Lumbar and Thoracic epidurals
■ Depending on the level of desired epidural placement, the epidural space may
be approached either medially (more common for lumbar epidurals) or
paramedially (more common for thoracic epidurals).
■ Midline Approach: The patient should be positioned with the back plane
perpendicular to the floor, so that as the epidural needle passes through the
back tissues into deeper tissues, it will stay midline. The needle entry site
should be between two spinous processes at the level of interest.
■ Paramedian Approach: The paramedian approach is preferred for thoracic
epidurals, or when the placement is difficult (due to severe arthritis,
kyphoscoliosis, and/or prior spine surgery, etc.).
FIG 2 • A. Positioning for epidural placement (Sitting).
B. Positioning for epidural placement (Lateral).
T E C H N I Q U E S

■ Preparation
■ Position the patient as described above and apply standard monitors: blood
pressure, ECG (electrocardiogram), end tidal CO2 (carbon dioxide), and
pulse oximetry.
■ Intravenous sedation (such as midazolam and/or fentanyl) may be
administered for patient comfort.
■ The spinous processes are typically palpable and can be used to identify the
midline and the desired site of epidural needle placement, as described above.
■ A sterile field is obtained by cleansing the area with chlorhexidine or similar
solution before placing a fenestrated drape.
■ Epidural Placement
■ After sterile skin preparation, a skin wheal is placed using a small gauge
needle (such as 27 gauge) to inject local anesthetic at the desired site of
epidural needle placement.
■ A 17- or 18-gauge Tuohy needle is generally used for epidural catheter
placement in adults.
■ When using a midline approach, the needle is introduced at the midline and
directed slightly cephalad (TECH FIG 1A).
■ When using a paramedian approach, the needle is introduced approximately
2 cm lateral to the inferior aspect of the superior spinous process of the
desired level. The needle is then advanced at a 10- to 30-degree angle toward
the midline (TECH FIG 1B).
■ When performing a lumbar or cervical epidural block, the needle is directed
only slightly cephalad. When performing a thoracic epidural block, the
needle must be directed more acutely to access the epidural space.
■ The initial subcutaneous tissues offer little resistance initially to the needle
passage. Note: if the paramedian approach is utilized, often the needle is
lateral to most of the interspinous ligaments and penetrates the paraspinous
muscles; it may encounter little resistance initially.
■ As the needle passes deeper, it will pass through supraspinous and
interspinous ligaments, and resistance will begin to increase.
■ Using the loss-of-resistance technique during epidural placement, a syringe
with a freely moveable plunger is attached to the epidural needle and filled

with either saline or air.
■ If the needle is correctly positioned in the ligament, the plunger will meet
with resistance. However, once the needle passes into the epidural space,
there will be a sudden loss of resistance, and the air or saline will freely inject
with no rebound.
■ Thus, the epidural space is located by the passage of a needle from an area of
high resistance (ligamentum flavum) to an area of low resistance (the
epidural space).
■ Once the epidural space is located, a flexible epidural catheter is fed through
the needle into the epidural space to the desired depth, typically 3 to 5 cm.
■ After the epidural catheter is in place and secured, aspiration is
recommended to ensure no CSF or blood can be aspirated.
■ A test dose (typically 3 mL of lidocaine 1.5% with 5 μg/mL epinephrine) is
injected via the catheter, and the patient is observed for signs and symptoms
of intravascular, subdural, or subarachnoid injection.
TECH FIG 1 • A. Midline needle insertion technique
for epidural placement. B. Paramedian needle
insertion technique for epidural placement.
■ Anesthetic Administration
■ Local anesthetic (with or without opioid) is then slowly titrated by bolus or
continuous infusion through the catheter to provide analgesia.
■ Local anesthetic selection is based on the desired speed of onset, degree of
motor blockade, and duration of anesthesia. Chloroprocaine, lidocaine, and
mepivacaine are short-acting local anesthetics commonly used for surgical

anesthesia. Longer-acting agents include ropivacaine and bupivacaine.
■ Local anesthetic dose may be estimated by using 1 to 1.5 mL local anesthetic
per desired dermatomal level of blockade. Once the initial blockade has
regressed 1 to 2 dermatomal levels, a second dose of approximately 50% of
the initial dose should maintain the original level of anesthesia. A continuous
infusion can also maintain anesthesia. The rate of infusion depends on the
concentration and type of local anesthetic chosen, the use of adjuvant
medications in the infusate, and patient-specific factors. Typically, a rate of 6
to 8 mL/h is adequate.
■ Dilute formulations of local anesthetics may be used in combination with
fentanyl and/or hydromorphone to provide postoperative analgesia.
■ Ropivacaine may produce less motor block than a similar concentration of
bupivacaine while maintaining a satisfactory sensory block.
■ The dose of epidural medication may need to be decreased in parturient,
obese, and elderly patients. This may be due to several factors, including a
potential for reduced CSF and/or a decrease in total epidural space in these
patient populations. In addition, hormonal factors in the parturient patient
population have been proposed to make neural endings more sensitive to
local anesthetics.
■ The addition of epinephrine to epidurally administered lidocaine may
prolong the duration of nerve block by up to 50%. The prolongation of
blockade with epinephrine added is less dramatic when using other local
anesthetics, such as bupivacaine and/or etidocaine.
■ Infusions are generally continued for 2 to 5 days following the surgery,
depending on patient characteristics and the nature of the surgical procedure
for which it was placed.
PEARLS AND PITFALLS
Sterility
■ Sterile conditions must be maintained at all times when placing an
epidural.
Locating the
epidural
space
■ Placement of the needle should be done logically, based on 3D
understanding of the anatomy. Needle redirection should not be
random. Systematic small angle needle changes should be made.

Intravascular
or intraneural
injection/local
anesthetic
toxicity
(LAST)
■ Aspiration for detection of blood or CSF is recommended prior to
injection through the needle or catheter to avoid toxic side effects
if epidural medication is injected intrathecally or intravascularly.
Test dosing may be helpful to avoid accidental intrathecal or
intravascular bolus.
Segmental
block
■ May be due to septations within the epidural space. Spread of
medication within the epidural space is gravity dependent. A
patchy block may be corrected by injecting additional local
anesthetic with the patient positioned to optimize coverage of the
areas that are spared. Sacral sparing may occur due to the large
size of the L5, S1, and S2 nerve roots.
Unilateral
block
■ May occur if medication is delivered via a catheter that has either
exited the epidural space and/or coursed laterally.
Failed
epidural
blocks
■ The loss of resistance technique is somewhat subjective. Local
anesthetic injection may be misplaced between ligaments or
paraspinous muscles. The paramedian approach can be more
challenging since the needle travels through softer tissues with
false loss of resistance. Epidural space anatomy may be variable,
making the spread of local anesthetics less predictable.
Block
assessment
■ The extent of sensory blockade may be assessed using a blunt
needle tip, cold, and/or other stimulus.
POSTOPERATIVE CARE
■ Following placement of an epidural, patients should continue to be monitored
for local anesthetic toxicity as long as the epidural medication is infusing.
Typically, this is done by clinical exam. Early signs and symptoms of local
anesthetic toxicity include tinnitus, blurred vision, dizziness, tongue
paresthesias, and/or perioral numbness. Symptoms may progress to seizures
and/or cardiac arrest if toxicity is severe and/or not treated early.
■ Maximum recommended dose(s) for some commonly used local anesthetics:
chloroprocaine and procaine 12 mg/kg; lidocaine and mepivacaine 4 to 5
mg/kg (7 mg/kg with epinephrine); bupivacaine and ropivacaine 3 mg/kg.
■ The dermatomal level of sensory blockade may be assessed to determine the
level of sympathectomy.
■ Patients should be assessed at least once daily until the epidural is removed.

This includes an evaluation of epidural function, query on side effects,
determination of patient-controlled epidural analgesia (PCEA) usage, degree of
motor block, and a check of the insertion site and dressing.
■ Depending on the epidural medication in use, patients should be educated on
possible weakness and fall risk and should be tested for muscle strength before
ambulation.
■ Patients should be encouraged to supplement their epidural analgesia with
nonopioid systemic analgesics as needed.
■ Routine dressing changes are not necessary and may increase the risk of
infection or catheter dislodgement. The dressing covering the epidural insertion
site should be left alone until the epidural catheter is removed.
■ Patients should be continually monitored by nursing staff for signs and
symptoms of epidural hematoma and/or epidural abscess, including back pain,
fever, and numbness or weakness that is progressive or in excess of what is
expected. These symptoms should prompt immediate evaluation by the
anesthesia team. If epidural hematoma or abscess is suspected, imaging and
neurosurgical consultation for surgical decompression should occur within
hours of the onset of symptoms to reduce the risk of permanent complications.
OUTCOMES
■ In addition to providing excellent postoperative anesthesia, epidural anesthesia
has been shown to be an important factor in the survival rate of flaps in breast
reconstruction plastic surgery cases due to the effects on the distribution of
direct blood flow to the microcirculation.4
■ A continuous thoracic epidural infusion is associated with reduced bleeding
due to hypotension during combined plastic surgeries involving breast,
abdomen, gluteus, and liposuction.5
■ Pain management strategies that include epidural anesthesia may be associated
with reduced morbidity and cost savings in abdominal wall reconstruction
surgeries.6
■ Epidural use is also associated with shortened length of hospital stay.6
COMPLICATIONS
■ In general, the use of epidural anesthesia is associated with a very low rate of
severe or disabling neurologic complications.
■ Overall, long-term complications (neurologic or otherwise) are very rare with
epidural placement. The incidence of serious complications following regional

anesthesia (including epidural, as well as spinal anesthesia, peripheral nerve
blocks, and intravenous regional anesthesia) is estimated to be 0.01%.7
■ Undiagnosed spinal stenosis has been identified as a risk factor for cauda
equina syndrome and paraparesis.8
■ Postdural puncture headache (PDPH) is a potential complication of epidural
placement that may occur after a “wet tap,” in which the epidural needle passes
through the epidural space and into the subarachnoid space. Subarachnoid
placement of the epidural needle is often made immediately apparent by the
free flow of CSF. Occasionally, however, the findings are subtler, and
subarachnoid placement of the epidural catheter is detected by aspiration of
CSF or by induction of a dense block with the test dose. Typically, PDPH is
described as bilateral, frontal, or retro-orbital, with extension into the neck. It is
characterized by symptom alleviation in the supine position, and worsening
when upright (“postural headache”). PDPH is postulated to be due to leakage
of CSF from a defect in the dura and intracranial hypotension. Initial treatment
is conservative and includes administration of IV fluids, recumbent
positioning, analgesics, and caffeine. Epidural blood patch may also be
considered if conservative treatment fails, although many PDPH are self-
limited.
■ Neuropathies from epidural placement are rare. Epidural abscess and/or
hematoma must be ruled out immediately (see below). Prolonged neuropathy
related to epidural placement may be associated with paresthesias from the
needle or catheter during placement, multiple attempts at block placement,
and/or a technically difficult block. Peripheral neuropathies may be due to
direct trauma to the nerve roots. Not all neurological deficits following
regional anesthetic are always due to the block.8
■ Epidural abscess is a rare complication of epidural placement and is a medical
and surgical emergency. Symptoms of an epidural abscess are often insidious
and delayed and progress from unexplained back or vertebral pain, to nerve
root or radicular pain, then motor or sensory deficits, and finally paraplegia
and/or paralysis. Prognosis is strongly related to the stage at the time of
diagnosis. If suspected, catheter should be removed, antibiotics started, and
neurosurgery consulted.8
■ Epidural hematoma is another rare complication of epidural placement. Risk
factors include a pre-existing bleeding diathesis or use of anticoagulation
medication(s). The American Society of Regional Anesthesia (ASRA)

guidelines should inform timing of epidural placement/removal and dosing of
anticoagulation when such medications are indicated. Symptoms of hematoma
include severe, sharp back and/or leg pain with motor weakness, and/or
sphincter dysfunction. Surgical decompression must occur within 24 hours, and
as soon as possible to maximize the chance of recovery.
■ Local anesthetic systemic toxicity (LAST) is a rare but potentially deadly
complication. Minimize risks with careful dose calculation.
REFERENCES
1. Arzola C, Davies S, Rofaeel A, et al. Ultrasound using the transverse
approach to the lumbar spine provides reliable landmarks for labor epidurals.
Anesth Analg. 2007;104:1188.
2. Chin KJ, Karmakar M, Peng P. Ultrasonography imaging facilitates spinal
anesthesia in adults with difficult surface anatomic landmarks. Anesthesiology.
2011;115:94.
3. Tran D, et al., Preinsertion paramedian ultrasound guidance for epidural
anesthesia. Anesth Analg. 2009;109(2):661-667.
4. de la Parra M, Camacho M, de la Garza J. DIEP flap for breast reconstruction
using epidural anesthesia with the patient awake. Plast Reconstr Surg Glob
Open. 2016;4(5):e724.
5. Nociti JR, et al. Thoracic epidural anesthesia with ropivacaine for plastic
surgery. Rev Bras Anesthesiol. 2002;52(2):156-165.
6. Fischer JP, et al. The use of epidurals in abdominal wall reconstruction: an
analysis of outcomes and cost. Plast Reconstr Surg. 2014;133(3):687-699.
7. Auroy Y, Narchi P, Messiah A, et al. Serious complications related to regional
anesthesia: results of a prospective survey in France. Anesthesiology.
1997;87(3):479-486.
8. Moen V, Dahlgren N, Irestedt L. Severe neurological complications after
central neuraxial blockades in Sweden 1990-1999. Anesthesiology.
2004;101(4):950-959.

5
CHAPTER
Section II: Foot, Ankle, and
Lower Leg
Fasciotomy of the Thigh,
Lower Leg, and Foot
Graeme E. McFarland and Jason T. Lee
DEFINITION
■ Fasciotomy is indicated to treat compartment syndrome and prevent nerve
injury and myonecrosis.
■ Compartment syndrome most often occurs in the setting of reperfusion of an
acutely ischemic limb or in severe limb trauma.
■ Compartment syndrome can also occur in the setting of occlusive deep vein
thrombosis (DVT) of the iliofemoral veins resulting in phlegmasia.
■ Fasciotomy is indicated for treatment of active compartment syndrome,
prophylactically for patients at high risk for compartment syndrome, or for
those in which a reliable exam is difficult to obtain (ie, head trauma) and
heightened concern for compartment syndrome.
■ Isolated compartment syndrome of the thigh is rare and often due to femur
fracture. The anterior compartment of the thigh is most commonly involved.1
ANATOMY
■ There are three fascial compartments of the thigh all surrounded by the strong
fascia lata.
■ Anterior:
• Muscles: Sartorius, articularis genus, rectus femoris, vastus lateralis, vastus
intermedius, and the vastus medialis

• Neurovascular: Femoral nerve
■ Medial (adductor):
• Muscles: Adductor longus/brevis/minimus, gracilis, pectineus, and external
obturator
• Neurovascular: Obturator nerve
■ Posterior:
• Muscles: Adductor magnus, biceps femoris, semitendinosus, and
semimembranosus
• Neurovascular: Sciatic nerve
■ There are four fascial compartments of the lower leg.
■ Anterior:
• Muscles: Tibialis anterior, extensor hallucis longus, extensor digitorum
longus, and the peroneus tertius
• Neurovascular: Anterior tibial artery and vein and the deep peroneal nerve
■ Lateral:
• Muscles: Fibularis longus/brevis
• Neurovascular: Superficial peroneal nerve
■ Superficial posterior:
• Muscles: Gastrocnemius, soleus, plantaris
• Neurovascular: Tibial nerve
■ Deep posterior compartment:
• Muscles: Tibialis posterior, flexor hallucis longus, flexor digitorum longus,
and popliteus
• Neurovascular: Tibial nerve, posterior tibial artery and veins, and the
peroneal artery and veins
■ There are technically nine compartments of the foot.
■ Medial compartment:
• Muscles: Abductor hallucis and flexor hallucis brevis
■ Lateral compartment:
• Muscles: Flexor digiti minimi brevis and abductor digiti minimi
■ Superficial central compartment:
• Muscles: Flexor digitorum brevis
■ Central central compartment
• Muscles: Quadratus plantae
■ Deep central compartment

• Muscles: Adductor hallucis compartment
■ Intrinsic compartment:
• Muscles: Four intrinsic muscles (compartments) between the 1st and 5th
metatarsals
DIAGNOSIS
■ Compartment syndrome can be diagnosed by directly measuring the
compartment pressures with a Stryker monitor set or with an arterial line
transducer system.
■ Compartment pressures greater than 30 mm Hg are indicative of compartment
syndrome.
■ The “6 P’s” of the compartment syndrome exam are pain, paresthesia, paresis,
pallor, pulselessness, and poikilothermia.
■ “Pain out of proportion to examination” and pain with passive flexion are the
most consistent signs of compartment syndrome.
■ A clinical suspicion for compartment syndrome warrants surgical intervention
regardless of compartment pressure measurement.
■ Paresthesias and paresis are late signs of compartment syndrome and are
indicative of poor functional outcomes.
■ Severe pain of the foot along with dorsal swelling can indicate compartment
syndrome of the foot.2
T E C H N I Q U E S
■ Thigh Fasciotomy (TECH FIG 1)
■ Anterolateral incision is made along the mid portion of the thigh for the
length of the thigh.
■ Make a straight longitudinal incision through the fascia lata and reflect the
vastus lateralis medially off the lateral intermuscular septum to release the
anterior compartment.
■ Make a small 2-cm incision in the lateral intermuscular septum and extend
proximally and distally for the length of the incision to release the posterior
compartment.
■ To release the medial or adductor compartment, make a medial incision

longitudinally for the length of the thigh. Incise the fascia lata for the length
of the incision.
TECH FIG 1 • Thigh Fasciotomy. This figure
demonstrates the two-incision approach for
fasciotomy of the thigh. The medial incision carried
deep through the fascia lata releases the adductor
compartment. The lateral incision carried deep
through the fascia lata releases the anterior
compartment. The lateral intermuscular septum is
then incised to open the posterior compartment. All
important neurovascular bundles should not be
exposed with this approach.
■ Lower Leg Fasciotomy
■ Anterior and lateral compartments are released through a lateral incision

made approximately 6 to 8 cm lateral to the anterior shaft of the tibia (TECH
FIG 2A).
■ The incision is carried from approximately 3 to 4 cm distal to the lateral
tibial tuberosity to approximately 2 to 3 cm proximal to the lateral malleolus.
■ Subcutaneous dissection is carried deep to expose the underlying fascia.
■ The anterior compartment is released by making an incision in the fascia 2
cm lateral to the tibia. The fascia is then cut for the length of the incision.
■ Identify the intermuscular septum between the anterior and lateral
compartments. Make an incision through the fascia 1 cm posterior to the
septum and then carry proximally and distally for the length of the incision,
taking care to protect the common peroneal nerve proximally which lies
behind the head of the fibula.
■ To release the superficial and deep posterior compartments, a longitudinal
incision is made medially 2 cm posterior to the medial border of the tibia for
the same length as the lateral incision (TECH FIG 2B).
■ Expose the underlying fascia and make the incision 2 to 3 cm posterior to the
tibia successfully releasing the superficial posterior compartment.
■ The deep posterior compartment is released by taking down the soleus
muscle from its attachment to the posterior aspect of the tibia and the
interosseous membrane. This needs to be carried for the length of the incision
(TECH FIG 2C).3
TECH FIG 2 • Lower leg fasciotomy. This figure
demonstrates the two-incision approach to a four
compartment fasciotomy of the lower leg. A. Lateral

incision is made 6 to 8 cm lateral to the anterior shaft
of the tibia and carried proximally 3 cm distal to the
tibial tuberosity and distally to 2 cm proximal to the
medial malleolus. B. The medial incision is created 2
cm posterior to the medial aspect of the tibia and
carried for the same length of the lateral incision. C.
The anterior compartment is released by cutting the
fascia anterior to the intermuscular septum and
carried for the length of the incision. The lateral
compartment is released in similar fashion through the
fascia lateral to the intermuscular septum. The
superficial posterior compartment is released by
incising the fascia just deep to the medial incision. The
deep posterior compartment is then released by
freeing the soleus from its attachments to the tibia.
■ Foot Fasciotomy
■ Dual dorsal incisions are used for release of all nine compartments.
■ A dorsal medial incision is made over the 2nd metatarsal and carried medial
and lateral to the 2nd metatarsal releasing the 1st and 2nd interosseous
compartments. Blunt dissection is carried deep to release the central
compartments and medial to release the medial compartment, if possible,
posterior to the 1st metatarsal (TECH FIG 3A).
■ A second dorsal incision is made over the 4th metatarsal and carried
medially and laterally to the 4th metatarsal releasing the 3rd and 4th
interosseous compartments. This can be carried laterally, posterior to the 5th
metatarsal to release the lateral compartment (TECH FIG 3B).
■ Occasionally, a medial incision is required to successfully release the medial
and central compartments.