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Year |
2001 |
|---|---|
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Question Number |
75. |
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Category |
Select |
Question
In acetabular exposure during a total hip replacement, the surgeon places a retractor behind the transverse acetabular ligament. What nerve can be damaged?
1- Superior gluteal
2- Inferior gluteal
3- Femoral
4- Obturator
5- Ilioinguinal
Figures
Answer (click for answer)
Answer- 4 Some variation of this question is on every year’s test. The Pelvis can be divided into four quadrants by drawing a line from the ASIS to the center of the acetabulum. A second line is drawn perpendicular. The quadrant and what is at risk in each is as follows-Posterior/Superior is the safe zone but the structures at risk are sciatic nerve, superior gluteal nerves and vessels. Posterior/Inferior is safe for short screws (<20 mm) structures at risk are Inferior gluteal nerve and vessels, internal pudendal nerve and vessels. Anterior/Superior never put a screw and be very careful with the retractors because the External iliacs (femoral vessel and nerves) are right there. And the last quadrant is the Anterior/Inferior where the retractor was placed. The structures at risk are the obturator nerve and vessels, hence the answer.
Reference: Miller MD(ed):Review of Orthopaedics. PA, WB Saunders, 2000 pp172, 250.