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“Almost all cases of hernia, with the possible exception of those in
young children, could undoubtedly be subjected to the radical operation
under local anesthesia.” This quote by Harvey Cushing reported in the
Annals of Surgery in 1900 illustrates that over 100 years ago the attributes of regional
anesthesia for lower abdominal and inguinal surgery were appreciated.
Ilioinguinal and iliohypogastric blocks are among the most frequently used
regional blocks performed for these surgical procedures. Postherniorrhaphy
pain is moderate to severe and often poorly controlled with opioids as
single modal therapy.1 Ilioinguinal and iliohypogastric
blocks have been shown to significantly reduce pain associated with
herniorrhaphy, regardless of whether the blocks are used as the primary
anesthetic2 or for pain control after
general3,4 or spinal5 anesthesia.
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Both the iliohypogastric and ilioinguinal nerves emanate from the first
lumbar spinal root. Superomedial to the anterior superior iliac spine, the
iliohypogastric and ilioinguinal nerves pierce the transversus abdominis to
lie between it and the internal oblique muscles. After traveling a short
distance inferomedially, their ventral rami pierce the internal oblique to
lie between the internal and external oblique muscles before giving off
branches, which pierce the external oblique to provide cutaneous sensation.
The iliohypogastric nerve supplies the skin over the inguinal region. The
ilioinguinal nerve runs anteroinferiorly to the superficial inguinal ring,
where it emerges to supply the skin on the superomedial aspect of the thigh
(Figure 42–1).
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Of note, the ventral rami of the lower intercostal nerves (T11 and T12)
also pierce the transversus abdominis muscle to lie between it and the
internal oblique. These latter nerves also supply sensation to the inferior
abdominal wall, and block of these nerves as well as the iliohypogastric and
ilioinguinal nerves is essential to provide anesthesia for procedures
involving the lower abdominal wall.
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Using the anatomic knowledge previously described, one needs to provide
a method of block that allows accurate placement of local anesthetic
between the internal oblique and external oblique muscles.
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Methods of local anesthetic administration that do not accurately define
placement between these muscular layers provide inconsistent anesthesia and
analgesia of the abdominal wall and inguinal region. Unfortunately, this may
result in the reporting of inadequate analgesia for a procedure that is more
a problem of technique than of the block itself.6 Accurate
block techniques must define the specific muscular layers of the abdominal
wall. The only way to facilitate this is to use loss of resistance
techniques that define fascial layers.
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Initially, the anterior superior iliac spine is palpated and a mark made 2
cm medial and 2 cm superior from it (Figure 42–2). After skin
preparation and infiltration with local anesthetic, a small ...