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Selective obturator nerve block was first described by Labat in
1922.1 More interest in obturator nerve block emerged a
few years later when Pauchet, Sourdat, and Labat stated, “obturator nerve
block combined with blocks of the sciatic, femoro-cutaneous nerves,
anesthetized the entire lower limb.” However, a lack of clear anatomic
landmarks, the block complexity, and inconsistent results were the reasons
why this block had been used infrequently. Historically, Labat's classical
technique remained forgotten until 1967, when it was modified by
Parks.2 In 1993, the interadductor approach was described
by Wassef,3 which was further modified by Pinnock in
1996.4 In 1973, Winnie introduced the concept of the
“3-in-1 block,” an anterior approach to the lumbar plexus using a simple
paravascular inguinal injection to anesthetize the femoral, lateral
cutaneous nerve of the thigh and obturator nerves.5 Since
its description however, many studies have refuted the ability of the 3-in-1
block to reliably block the obturator nerve with this technique. However,
with the introduction of modern nerve stimulators, selective blockade of the
obturator nerve has become more reliable and has seen a resurgence of
interest in recent times.
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Obturator nerve block is used to treat hip joint pain and is used in
the relief of adductor muscle spasm associated with hemiplegia or
paraplegia. Muscle spasticity is a relatively common problem among patients
suffering from central neurologic problems, such as cerebrovascular
pathology, medullar injuries, multiple sclerosis, and infantile cerebral
palsy. Spasticity of the adductor muscle induced via the obturator nerve
plays a major role in associated pain problems and makes patient grooming
and mobilization very difficult. Obturator block, tenotomies, cryotherapy, botulin toxin
infiltration, surgical neurolysis, and muscle interpositions all have been
suggested to remedy this problem.6–9 A number of
diagnostic or therapeutic procedures on the knee and thigh can be performed
by combining obturator nerve block with block of the sciatic, lateral
cutaneous nerve and femoral nerves. Common clinical practice is to combine a
sciatic nerve with the femoral nerve block for surgical procedures distal to
the proximal third of the thigh. When deemed necessary, addition of a
selective obturator nerve block may reduce intraoperative discomfort,
improve tourniquet tolerance, and improve the quality of postoperative
analgesia in these cases.
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Obturator nerve block is also occasionally used in urologic surgery to
suppress the obturator reflex during transurethral resection of the lateral
bladder wall. Direct stimulation of the obturator nerve by the resector as
it passes in close proximity to the bladder wall results in a sudden,
violent adductor muscle spasm. This is not only distracting to the surgeon,
but also potentially dangerous, increasing the risk of serious complications
such as bladder wall perforation, vessel laceration, incomplete tumor
resection, and obturator hematomas.10,11 Prevention
strategies include muscle relaxation, reduction in the intensity of the
resector, the use of laser resectors, shifting to saline irrigation,
peri-prostate infiltrations, and/or endoscopic transparietal
blocks.12–16 However, a selective ...