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Victor Pauchet first described the sciatic nerve block in
L'Anesthésie Régionale in 1920:
“the site of needle insertion for blocking the sciatic nerve at the level
of hip: 3 cm along the perpendicular that bisects a line drawn between the
greater trochanter and the posterior superior iliac
spine.”1 Although this technique is referred to as “The
classic approach of Labat,” it was in fact first described by Labat's
teacher, Pauchet. Perhaps the reason for the name designation comes from the
fact that the sciatic nerve block was first described in anesthesia
literature in 1923 by Gaston Labat in his book, Regional Anesthesia:
Its Technic and Clinical Application.2 Of note,
Labat in the same year founded the American Society of Regional Anesthesia
(ASRA). Anecdotally, Labat intended to name the new group “the Labat
Society” in his honor, but the name ASRA remains today as we know it.
Labat's book went through several reprintings of the first edition and was
one of the first English language anesthesia textbooks of regional
anesthesia in the United States. Curiously, this book was similar to
L'Anesthésie Régionale, written by
Labat's tutor, Pauchet, from 1918 to 1920 in the University of Paris.
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Alon Winnie eventually modified the Labat approach in
1975.3 In 1963, Beck4 described an anterior
approach, and, in 1975, Raj proposed a lithotomy
approach.4,5 These alternative approaches were devised to
allow the sciatic nerve to be blocked in the supine patient. Since its
original description, a number of new approaches to sciatic nerve blocks
were proposed, most of which include minor modifications of questionable
clinical significance. Based on the clinical studies of
various approaches, the most useful of these newer techniques appear to be
the subgluteal and parasacral approaches introduced by di Benedetto and
Mansour, respectively.6–8 Discussion of all described
techniques and approaches is beyond the scope of this chapter. Instead, this
chapter focuses on the classic approach to sciatic nerve block, parasacral
and subgluteal modifications, and the anterior approach.
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Indications & Contraindications
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Indications for sciatic nerve block include lower-limb surgery, often
combined with a femoral or psoas compartment block.8 For
distal surgery of the lower extremity, however, more distal approaches such
as ankle block or popliteal sciatic nerve block are preferable when
feasible. Note that the sciatic nerve block almost always needs to be
combined with supplemental block, which involves components of the lumbar
plexus (femoral nerve).
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Contraindications to sciatic nerve block are few, and may include local
infection and bed sores at the site of insertion, coagulopathy, preexisting
central or peripheral nervous systems disorders, and allergy to local
anesthetics.
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The union of the lumbosacral trunk with the first three sacral nerves
forms the sacral plexus (Figure 37–1). The lumbosacral trunk
originates from the anastomosis of the last two lumbar nerves with the
anterior branch of the first ...