Brian P. Jacob, David C. Chen, Bruce Ramshaw, Shirin Towfigh (eds.) - The SAGES Manual of Groin Pain-Springer International Publishing (2016)

20. Management of Groin Pain…
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successful or specific, as they rely on large volumes of anesthetic
infiltrated over a large area to ensure spread to the involved nerves and
tissue planes. For example, four different landmark-based techniques
medial to the ASIS and above the inguinal ligament are commonly advocated
for ilioinguinal nerve block; however, high failure rates are reported,
even in children where the anatomy is generally superficial [ 15 ].
Localizing Options
Ultrasound guidance offers several advantages that make it highly
suited for diagnosing and treating groin pain. The machines are portable,
there is no radiation exposure, the superficial locations of the “border
nerves” can be easily visualized, and the lack of surrounding bony structures
allows for in-plane needle advancement for accurate, safe, and
highly specific diagnostic and therapeutic interventions. Nerve stimulation
may be included to ensure close proximity to the involved nerves
and can also be of diagnostic value, as stimulating the injured nerve may
replicate the patient’s usual pain. An initial block of the affected nerve
using a low volume of local anesthetic can be performed with confirmation
of sensory block in the expected distribution. If this block relieves
the patient’s usual pain, then neuralgia in this distribution is the likely
diagnosis. If pain continues despite appropriate block, then another
source for pain should be investigated.
1. Iliohypogastric and ilioinguinal nerve block—A linear high-frequency
probe is placed with the lateral end at the ASIS and the
probe oriented in the transverse axis to visualize the three layers
of the abdominal wall. A needle is advanced in plane from medial
to lateral with the target between the transversus abdominis and
internal oblique layers, where the nerves can often be visualized
1–2 cm medial to the ASIS [ 16 ].
2. Genitofemoral nerve block—A linear high- frequency probe is
placed perpendicular to the inguinal ligament with the medial
end at the pubic tubercle. The spermatic cord and accompanying
nerve are visible in cross section within the inguinal canal, and a
needle can be advanced in plane from medial or lateral with the
target within the canal and outside the cord [ 16 ].
3. Lateral femoral cutaneous nerve block—A linear high-frequency
probe is placed with the lateral end at the ASIS and the probe
oriented along and inferior to the inguinal ligament. The nerve is