Ultrasound-guided blocks of the ilioinguinal and iliohypogastric nerve: accuracy of a selective new technique confirmed by anatomical dissection.
BACKGROUND
Ilioinguinal and iliohypogastric nerve blocks may be used in the diagnosis of chronic groin pain or for analgesia for hernia repair. This study describes a new ultrasound-guided approach to these nerves and determines its accuracy using anatomical dissection control.


METHODS
After having tested the new method in a pilot cadaver, 10 additional embalmed cadavers were used to perform 37 ultrasound-guided blocks of the ilioinguinal and iliohypogastric nerve. After injection of 0.1 ml of dye the cadavers were dissected to evaluate needle position and colouring of the nerves.


RESULTS
Thirty-three of the thirty-seven needle tips were located at the exact target point, in or directly at the ilioinguinal or iliohypogastric nerve. In all these cases the targeted nerve was coloured entirely. In two of the remaining four cases parts of the nerves were coloured. This corresponds to a simulated block success rate of 95%. In contrast to the standard 'blind' techniques of inguinal nerve blocks we visualized and targeted the nerves 5 cm cranial and posterior to the anterior superior iliac spine. The median diameters of the nerves measured by ultrasound were: ilioinguinal 3.0x1.6 mm, and iliohypogastric 2.9x1.6 mm. The median distance of the ilioinguinal nerve to the iliac bone was 6.0 mm and the distance between the two nerves was 10.4 mm.


CONCLUSIONS
The anatomical dissections confirmed that our new ultrasound-guided approach to the ilioinguinal and iliohypogastric nerve is accurate. Ultrasound could become an attractive alternative to the 'blind' standard techniques of ilioinguinal and iliohypogastric nerve block in pain medicine and anaesthetic practice.
Eichenberger
U
U
Department of Anaesthesia and General Intensive Care (B), Medical University of Vienna, A-1090 Vienna, Austria. urs.eichenberger@insel.ch
Greher
M
M
Kirchmair
L
L
Curatolo
M
M
Moriggl
B
B
D000005:Abdomen / Q000294:innervation; D000009:Abdominal Muscles; D034861:Abdominal Wall; D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D004396:Coloring Agents; D004210:Dissection / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D010525:Peripheral Nerves / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D014159:Transducers; D014463:Ultrasonography
D004396:Coloring Agents