Interscalene Brachial Plexus Block
Interscalene PNB anesthetizes the brachial plexus, typically at the C6
nerve root. The popularity of this block relates to its utility in providing
long-lasting analgesia after painful ambulatory orthopedic shoulder surgery.
When Hadzic17 compared interscalene block to GA in 50
patients for outpatient rotator cuff surgery, he found that patients with
PNB had more frequent postanesthesia care unit (PACU) bypass (76% vs
16%), suffered less pain, ambulated earlier, met discharge criteria
sooner (123 min vs 286 min), had fewer unplanned readmissions (0 vs 16%),
and were more satisfied with their care. Brown coworkers18
found similar results and fewer postoperative side effects after
interscalene block versus GA (pain 14% vs 45%, PONV 8% vs 43%,
urinary retention 0% vs 25%, hospital admissions 17% vs 48%). In
a large retrospective review comparing interscalene block with GA, D'Alessio
and colleagues19 further demonstrated reductions in
nonsurgical intraoperative time (29 ± 9 min vs 49
± 12 min) and PACU time (72 ± 24
min vs 102 ± 40 min), as well as decreased anesthetic
side effects in PACU.
Al-Kaisy's group20 prospectively compared interscalene
block with 10 mL 0.125% bupivacaine against placebo for outpatient
shoulder arthroscopy done under GA. They found decreased pain and morphine
use (2.7 ± 2.6 mg vs 9.5 ± 5.2
mg) during the PACU stay and a faster achievement of discharge criteria (139
± 34 min vs 193 ± 59 min) with
the nerve block. They also noted no difference between patient groups in
their 24-h opioid use following PNB resolution at 2 h. In a similar study,
Laurila and associates21 compared a low-volume
interscalene block with a subacromial bursa block and placebo. They also
found the interscalene block to be the most effective for early
postoperative pain control.
Singelyn and coworkers22 compared patients undergoing
arthroscopic acromioplasty with interscalene PNB, isolated suprascapular
nerve block, intraarticular LA, or systemic opioids. They concluded that
interscalene PNB was most proficient, that suprascapular block was an
alternative option, but that intraarticular LA injection offered no benefit
to intravenous (IV) opioids.
Failure to achieve surgical anesthesia with interscalene PNB ranges from 0
to 9.5%,18–20,23 requiring conversion of 16% of
cases to GA.18 Although side effects often include
shortness of breath, dysphonia, and Horner's syndrome18,24
they rarely thwart discharge planning. More importantly, studies on
inpatients have demonstrated a low risk of neurologic injury. In a series of
520 patients having single-injection or continuous interscalene block,
Borgeat and colleagues25 found that 14% had
paresthesia, dysesthesia, or nonsurgical pain 10 days after surgery. The
majority of these symptoms gradually resolved, leaving only one patient
symptomatic with a plexus injury 9 months after surgery. The combination of
an efficacious PNB, its relatively benign clinical application, and
demonstrated benefits compared with GA ensure ongoing use of the
|Interscalene brachial plexus block|
This block is useful for shoulder and upper arm surgery.
It has an excellent clinical efficacy.
The risk of block inadequacy and similar risk of transient neuropathy is
Horner's syndrome and transient dyspnea are common.
Supraclavicular Brachial Plexus Block
The supraclavicular PNB approaches the brachial plexus trunks between
the clavicle and the first rib. Due to the close proximity of the trunks at
this level and the close apposition of the surrounding fascia, the
supraclavicular block can provide more reliable anesthesia with faster onset
distal to the shoulder than the axillary approach. Bedder and
associates26 showed that supraclavicular block using
0.5% bupivacaine provided onset of sensory anesthesia in 4.0
± 1.2 min and peak effect in 17.7 ± 1.8 min. Consequently, supraclavicular block is ideal for
rapid-turnover outpatient procedures of the elbow, wrist, and hand. Because
the axillary nerve may be spared with this PNB, supraclavicular block is not
always reliable for shoulder surgeries.27 With the
supraclavicular block, the needle insertion site is near the dome of the
lung. Anecdotal reports have associated the “plumb-bob” technique with an
unacceptably high risk of pneumothorax, leading many practitioners to avoid
this block. Nevertheless, no study supports this concern or warrants
prolonged observation of a patient after an uneventful anesthetic and
recovery. To the contrary, Franco and Vieira28
demonstrated the safety of supraclavicular PNB in a series of 1001 patients
anesthetized by both consultants and residents. Touting a clinical efficacy
of 97.2%, no major complications were reported. These data highlight the
potential usefulness and safety profile of this as yet underutilized
Supraclavicular block has the fastest onset of any brachial plexus
The success rate is high.
Supraclavicular block is suitable for upper extremity procedures, excepting
those for the shoulder.
The risk of pneumothorax is low with adequate training.
Infraclavicular Brachial Plexus Block
Infraclavicular PNB is approached at the division and cord level of the
brachial plexus. PNB at this level provides anesthesia appropriate for
procedures done on the mid to distal upper extremity. As with
supraclavicular PNB, this block has a high success rate and a low risk of
Hadzic and coworkers32 contrasted patients who
underwent ambulatory wrist surgery with GA with those who received
infraclavicular PNB. As a group, those patients with GA had lower PACU
bypass rates (24% vs 76%), higher rates of PONV (32% vs 8%), and
more numerous requests for analgesia (48% vs 0%). Fewer patients in
the infraclavicular group reported inability to concentrate in the PACU
(8% vs 56%), though statistical significance was lost by the time that
discharge criteria were met. Although the infraclavicular block performed in
the operating room prolonged induction by 5 min, total operative time was
similar to GA. Discharge criteria were met more quickly in the PNB group
(100 ± 44 min vs 203 ± 91 min),
and opioid use was similar in both groups over the first 48 h.
Desroches33 used infraclavicular PNB to achieve surgical
anesthesia in 91% of outpatients and required 7 min or less for block
execution. The risk of pneumothorax remained low at 0.7%, although
published rates of vascular puncture can be as high as
17%.34 The newer techniques with needle redirection
laterally should reduce the risk of pneumothorax to practically negligible.
This technique is time-efficient.
It is suitable for upper extremity procedures distal to the shoulder.
The success rate is high.
The risk of noncompressible vascular puncture is low.
Axillary Brachial Plexus Block
The brachial pulse allows for facile location of the axillary artery
and the common sheath that invests the branches of the brachial plexus. This
reliable landmark, the low risk of pneumothorax, and the usefulness of this
PNB for surgical anesthesia of the mid to distal upper extremity has helped
to make the axillary block the most popular PNB in the United
States.8,9 Axillary PNB can be successfully executed with
a nerve stimulator, paresthesia, or the transarterial technique.
Septa within the fascial sheath35,36 may limit the
rate of diffusion of LA to terminal nerves and result in individual nerve
sparing. This can in turn lead to nerve sparing as well as delayed
anesthetic set-up. In an attempt to overcome this problem, the stimulation
and injection of individual nerves has been studied.37
Bouaziz and associates38 attempted to make an additional
improvement in outcome by utilizing 0.5% bupivacaine to anesthetize the
ulnar and median nerves and 2% lidocaine for the others. This strategy
resulted in long-lasting anesthesia of a palmar incision with faster
recovery of the remaining arm. Koscielniak-Nielsen and
coworkers39 investigated success and patient perceptions
using multiple-stimulation in unmedicated outpatients. They found that
electrolocation was uncomfortable for 80%, but that 98% would have the
same technique in the future. Thirteen percent would request sedation in the
future, and 95% were comfortable being discharged with an insensate
extremity. Despite this success, although block performance only took an
average of 9.8 min, block onset took an additional 23 min using a 1:1
mixture of 0.75% ropivacaine and 2% mepivacaine. Utilization of a
preoperative “block room” can eliminate the delay of LA set-up, decrease
nonsurgical operating room time, and improve overall
Outpatient axillary PNB is not without the risk of block failure or
complication. Davis and colleagues42 reviewed 530 such
blocks and found a 7% incidence of block failure requiring GA and a 2
% incidence of inadequate postoperative analgesia requiring admission.
Complications were rare, with a less than 1% incidence of LA toxicity and
no persistent neurologic deficits. Cooper's group43
reviewed the anesthetics of 1149 outpatients and found that 93% of those
who responded would have an axillary block in the future. Those who were
reluctant to have another block were more likely to have experienced any
side effect (ie, bruising or pain in the axilla).
Chan and coworkers44 prospectively compared axillary block
with IVRA and GA in 126 individuals having outpatient hand surgery. The RA
groups required less opioids and had a decreased incidence of PONV
(p < 0.05). But the induction time, overall discharge time, and cost
were least in the IVRA group (p < 0.05).
Axillary block is efficacious for elbow, forearm, and hand
It is easy to perform with minimal risk of complications.
The possibility of nerve sparing exists, with up to 7% risk of block
Axillary block has the slowest onset time of all brachial plexus techniques.
Iliohypogastric–Ilioinguinal Nerve Block
The iliohypogastric (T12, L1) and ilioinguinal (L1) nerves provide
sensory innervation to the inferior abdomen and buttocks, the superomedial
thigh, and part of the external genitalia. Block of these nerves is easily
and efficiently performed 2 cm medial and 2 cm superior to the anterior
superior iliac spine. Alternatively, the surgeon can apply LA to the nerves
directly during an inguinal hernia repair. In the literature, the
iliohypogastric–ilioinguinal nerve block has been used successfully as an
adjunct to GA in surgeries such as inguinal herniorrhaphy and
varicocelectomy.45 When compared with
placebo,46 local wound infiltration,47
subarachnoid block (SAB),48 or GA
alone,48 ilioinguinal–iliohypogastric nerve block has
been associated with decreases in postoperative pain scores,46–48 postoperative opioid requirements,46,47
PONV,48 cost,48 and discharge
times.48 Complications with this nerve block are usually
related to the proximity of these nerves to the femoral nerve. Inadvertent
femoral nerve block49,50 can result in difficulty with
ambulation and may be difficult to differentiate from direct surgical trauma
to the nerve. Overall, although data demonstrate its usefulness as an
adjunct for hernia surgery, the magnitude of benefit seen may not support
its routine use when compared with the simple alternative of surgical wound
infiltration and multimodal analgesia.
|Ilioinguinal–iliohypogastric nerve blocks|
These blocks are and easy to perform adjunct for inguinal
herniorrhaphy or varicocelectomy.
There is a risk of inadvertent femoral nerve block.
The lumbar plexus block anesthetizes the femoral, obturator, and
lateral femoral cutaneous nerves more reliably than more distal approaches
to the femoral nerve.51 Although lumbar plexus block is
useful for procedures that range from hip52 to
knee53–55 arthroplasty, the expansiveness of this block
may be disadvantageous to outpatients unless a short-acting local anesthetic
is used (eg, chloroprocaine). Loss of iliopsoas muscle function prevents
flexion at the hip and increases the difficulty of ambulating with crutches
or even a walker. Furthermore, there exists a risk of epidural spread of LA,
ranging between 1.8% to 8.9%.56,57 This may be
caused by injecting LA too medially after eliciting the muscular response of
a single nerve root. Such a mishap may prevent a patient from walking and
delay discharge when long-acting local anesthetics are used.
Knee arthroscopy remains a commonly performed ambulatory surgical
procedure for which lumbar plexus PNB may be useful. Two randomized
prospective trials compared lumbar plexus PNB with SAB or GA for this
procedure. Jankowski and associates58 found that more than
twice the number of GA patients (45%) required analgesics in PACU versus
those who received lumbar plexus PNB (21%) or SAB (14%). Although pain
scores were higher at all points in the GA group, because mean scores were
low even in this group they questioned whether lumbar plexus block was
really necessary for this procedure. Hadzic and
coworkers59 presented compelling support for a lumbar
plexus block and sciatic nerve block over GA for knee arthroscopy. By
utilizing lumbar plexus and sciatic PNBs they were able to decrease severe
PONV from 62% to 12%, odynophagia from 60% to 28% and time to
achieve discharge criteria from 205 ± 94 min to 131
± 62 min. The percent achieving PACU bypass increased
with PNBs from 24% to 72%. Although PNBs (placed in the operating
room) lengthened the time required for induction by 7 min, there was no
overall increase in length of time spent in the operating room.
|Lumbar Plexus Blocks|
Lumbar plexus blocks can provide anesthesia for hip arthroscopy and,
in combination with sciatic nerve blockade, for extensive knee surgery.
This is the only consistent technique for coverage of “3-in-1”
The risk of epidural spread is ≤10%.
Weakness of hip flexors can impede patient discharge.
Femoral Nerve Block & Fascia Iliaca Block
Anesthesia of the proximal lower extremity including the anterior knee
and medial calf can be achieved with a femoral nerve block or a fascia
iliaca block. Both of these PNBs can be performed on a supine patient with
easily identified landmarks. Because anesthesia of the lateral femoral
cutaneous and obturator nerves are often desired in addition to femoral
block, individual anesthesiologists have attempted to increase LA volumes
and to apply distal pressure to achieve these ends.60 The
“3-in-1” technique, however, fails to consistently block the lateral
femoral cutaneous and especially the obturator nerve.51,61–63
Femoral PNB has been employed for knee arthroscopy with varying
success.64,65 More impressive results have been obtained
for painful procedures, such as anterior cruciate ligament (ACL)
reconstruction. Mulroy and coworkers66 compared femoral
PNB to sham block in 55 patients who had already received either epidural or
intraarticular analgesia after ACL repair. Overall, the best analgesia was
seen in patients with femoral PNB, whereas half of patients in the sham
group reported pain VAS ≥5/10. Furthermore, a trend of lower
opioid use over 36 h was identified. This was substantiated in a
retrospective study by Williams and colleagues,67 who
found that outpatients garnered some benefit from femoral PNB for minor knee
surgery but large benefit from more invasive procedures. Not only did
femoral PNB provide improved analgesia in these individuals, it also reduced
unanticipated hospital admissions. Further analysis found that the addition
of sciatic PNB for invasive knee surgery augmented those advantages. Of
note, without PNBs, invasive knee surgery held a four to six times greater
risk of the patient being admitted to the hospital. In a more recent
study,68 this group estimated the cost savings afforded by
PNBs for ACL repairs. Assuming a PACU bypass rate of 82% and an unplanned
admission rate of 4%, their institution would save $98,600 after 250
When femoral PNB is used for minor knee surgery, such as knee arthroscopy,
it has been shown that providing broader coverage of the lumbar plexus is
beneficial. Bonicalzi and Gallino69 increased femoral PNB
volume from 10 to 20 mL in an attempt to broaden “3-in-1” coverage, which
resulted in better operative conditions and decreased postoperative
discomfort. Patel and coworkers65 divided knee arthroscopy
patients into those receiving GA, combined femoral and lateral femoral
cutaneous PNB, and femoral PNB with sham lateral femoral cutaneous block.
Again, operative conditions were improved, and postoperative complaints of
pain decreased (from 27% to 3%) with broader nerve block coverage.
Although PNB of the femoral nerve group remains an effective mode of
anesthesia for knee surgeries ranging from knee arthroscopy to ACL
reconstruction, arguing its use for less invasive surgeries of the knee on
grounds of postoperative analgesia alone is difficult. For more invasive
lower extremity surgeries, however, the studies do warrant as broad an
application of LA to this nerve group as can be reasonably afforded.
|Femoral Nerve Block and Fascia Iliaca Block|
These blocks are easy to perform for anteromedial thigh and medial
They afford improved postoperative analgesia for invasive knee procedures.
Variable blockade of lateral femoral cutaneous and obturator nerves limits
anesthetic applicability and analgesic efficacy for extensive lower
Proximal Sciatic Nerve Block
Proximal blockade of the sciatic nerve proves a useful adjunct to PNB
of the thigh. Several studies have evaluated the utility of combined PNBs
for knee arthroscopy. In one such investigation, Sansone and
colleagues70 utilized combined femoral–sciatic nerve
block in 601 patients and were required to provide further intraoperative
pain relief only 12% of the time and sedation 20% of the time. Out of
this group, only 0.7% required conversion to GA. No neurologic deficits
were revealed at 1 month's follow-up.
Other studies have demonstrated effective use of a femoral–sciatic
nerve block for knee arthroscopy but failed to show a prolonged analgesic
benefit from mepivacaine compared with “fast track” GA71
and unilateral72 or bilateral73 SAB.
When compared with propofol–remifentanil GA, the femoral–sciatic nerve
block group had less intraoperative bradycardia (0% vs 21%) and
hypotension (0% vs 36%) as well as lower postoperative pain VAS scores
in PACU (0 vs 7 out of 10). However, 12% of patients receiving
femoral–sciatic block complained of mild pain during surgery, one patient
required fentanyl and one a GA. Addition of a sciatic nerve block to a
femoral or lumbar plexus nerve block likely provides better tourniquet
anesthesia than femoral or lumbar plexus nerve block alone. This may be
useful for the patient who requests little or no intraoperative sedation.
Similar to the data discussed with femoral nerve blocks, the analgesic
benefit from combined femoral–sciatic nerve block is more apparent when
more invasive procedures are performed with long-acting
LA.67 Nakamura and colleagues74 compared
recipients of GA (n = 36) to patients who underwent femoral–sciatic nerve
block (n = 31) for ACL reconstruction. The combined PNB allowed 90% of
patients to avoid hospitalization postoperatively, and as a result saved
$2,907 per patient.
|Proximal Sciatic Nerve Block|
Proximal sciatic nerve block is an anesthetic and analgesic adjunct
to lumbar plexus nerve block for complex knee surgery and an adjunct to
saphenous nerve block for surgery below the knee.
It blocks the posterior cutaneous nerve of the thigh needed for thigh
The risk of neuropathic complications is low.
It blocks hamstring musculature, augmenting operative extremity weakness.
It can inhibit parasympathetic control of bladder emptying.
Distal Sciatic Nerve Block
Both proximal and distal sciatic nerve blocks have broad application
for foot and ankle surgery. Utilization of a more distal PNB preserves the
function of the hamstring muscle group. A more distal approach, however,
typically necessitates the use of either a calf tourniquet or potent
sedation in the presence of a thigh tourniquet. With either sciatic nerve
block approach, a femoral or saphenous nerve PNB can provide anesthesia to
the spared distal extremity territory of the medial calf or ankle.
Posterior75 or lateral76,77
popliteal fossa PNB interrupts sciatic conduction prior to the division of
the tibial and peroneal branches of the nerve. Since this PNB is relatively
safe and easy to perform with a high degree of patient satisfaction, it
proves a model block for ambulatory surgery of the distal lower
Reliability was demonstrated by Singelyn and coworkers,79
who investigated the posterior popliteal fossa sciatic nerve block with
1% mepivacaine or 0.5% bupivacaine in 507 patients having 625 blocks.
Femoral nerve anesthesia was provided separately when needed. Surgical
anesthesia occurred in 92%, supplemental analgesia was necessary in
5%, and GA in only 3% of cases. Discomfort associated with the block
procedure was minimal in 89%, moderate in 9%, and severe in 2%. Of
the 466 patients who rated their satisfaction with perioperative analgesia,
95% were completely satisfied, 4% expressed moderate reservations, and
1% expressed major reservations.
Although some in busy ambulatory practices find it challenging to achieve
adequate popliteal fossa sciatic nerve block in a timely fashion,
Fernandez-Guisasola associates80 have provided promising
data comparing two LA solutions for outpatient foot and ankle surgery. They
found rapid onset of anesthesia using either 40 mL of 0.5% ropivacaine
(6.5 ± 5.1 min) or 1% mepivacaine (6.2
± 3.7 min). As expected, sensory block following
ropivacaine significantly outlasted that from mepivacaine (20.7
± 6.2 h vs 6.5 ± 1.7 h).
The analgesic duration of a popliteal fossa sciatic nerve block can exceed
that for an ankle block or wound infiltration, two alternative anesthetics
for foot surgery. McLeod and colleagues81 compared
popliteal fossa PNB with ankle block in 40 patients undergoing GA for foot
surgery. Bupivacaine (20 mL of 0.5%) was utilized to provide
postoperative analgesia. Both techniques proved to be efficacious, though
popliteal fossa PNB yielded 1080 min of analgesia versus 690 min with ankle
block. The same group77 further studied lateral popliteal
fossa PNB versus subcutaneous infiltration of the wound with similar results
lateral popliteal fossa provided 1082 min of analgesia versus 373 min with
A novel use of popliteal fossa sciatic nerve block was described by Vloka
and associates82 when they combined this block with a
posterior cutaneous nerve block of the thigh for short saphenous vein
stripping. This technique provided an acceptable alternative to SAB and was
associated with fewer requests for analgesia in PACU (21% vs 64%),
faster recovery (67 ± 10 min vs 122 ± 50 min in PACU), and earlier discharge (total time in hospital 222
± 53 min vs 294 ± 68 min). Thus
it appears, in principle as well as in practice, that preserved hamstring
muscle function combined with dense postoperative analgesia allow for early
mobilization of ambulatory patients and support the use of distal sciatic
PNB in this setting.
|Distal Sciatic Nerve Block|
This block is easy to perform for foot or ankle surgery.
It provides longer lasting analgesia than an ankle block.
It preserves hamstring function.
Dermatomal anesthesia of the thoracolumbar trunk can be achieved by
injecting LA into the paravertebral space deep to the transverse processes
to bathe the nerve roots after their exit from the intervertebral foramina.
Performance of PVBs has provided anesthesia as well as postoperative
analgesia for outpatient breast,41,83–87 inguinal
hernia,88–91 and ileostomy revision
Decreased opioid requirements and subsequent PONV are important benefits
of PVBs when used for potentially emetogenic surgery. Klein and coworkers
utilized PVB with 0.5% bupivacaine for hernia89 surgery
and for mastectomy.41 After mastectomy, the PVBs served to
reduce the number of patients requiring postoperative analgesia from
97.8% to 25% compared with those who received GA.87
Because the technique is typically performed as a “blind” technique,
without the use of nerve stimulation, a clear endpoint is not always
achieved prior to injection of LA. This may be the source of the published
variability in rates of successful blocks.41,85,87 This
variability, combined with the proximity of the needle tip to the lung, with
consequent risk of pneumothorax (0–6.7%),41,83–87
warrants at a minimum operator experience with PVBs prior to routine use of
this block in the ambulatory setting.
Paravertebral block is useful for anesthesia of the thoracolumbar
It provides the longest lasting analgesia after breast or hernia surgery.
Variable success rates have been reported.
Some risk of pneumothorax exists.