Effect of lithotomy positions on strain of the obturator and lateral femoral cutaneous nerves

Abstract

The purpose of this study was to determine if various lithotomy positions increase strain on the obturator and lateral femoral cutaneous nerves in fresh adult cadavers. A static load cell was used to record strain changes of the obturator and lateral femoral cutaneous nerves in the pelvis and anterior thigh when the lower limbs were placed in three sets of positions of varying hip abduction and flexion. The means of the strain measurements, which were measured in grams in all positioning angles were compared to the baseline 0 degrees measurements. Analysis of variance was calculated for the differences. Flexion of the hip did not increase strain on either nerve. Abduction to 30 degrees or 45 degrees increased strain by more than 30 g on the obturator nerve (P < 0.05) but not the lateral femoral cutaneous nerve. The addition of 45 degrees or more of flexion to abduction negated the strain increase on the obturator nerves seen with abduction alone. Nerve strain >30 g has been associated consistently with nerve dysfunction, disrupting axonal transmission, and causing structural neural damage. Our findings suggest that concomitant hip flexion should be used when placing anesthetized patients in a lithotomy position that includes abduction of the lower limbs to >30 degrees to decrease the risk for perioperative neuropathy of the obturator nerve.

Obturator neuropathy complicating elective laparoscopic tubal occlusion

“…The nerve is probably injured most frequently during hip surgery due to stretch, compression by a retractor, or encasement in cement 2, 11. Although lithotomy position can strain the nerve,8 one large prospective study found that neuropathy developed in only 5 of 991 surgical patients 15. Compression of the obturator during delivery can occur from the fetal head or forceps in the pelvic canal 7.…”

Kalca Eklemi Cevresi Yumusak Dokulari

“…Kitle etkisine bağlı basılar sıklıkla obturator kanal düzeyinde veya uyluk proksimalinde herni, periartiküler kist veya bursa nedeniyle görülür. Genitoüriner cerrahilerde uzun süre litotomi pozisyonunda kalmaya, kalça cerrahisinde ise aşırı gerilmeye bağlı etkilenebilir [8]. Spor ile ilişkili obturator nöropati, obturator sinir anterior dalının adduktor brevis tendinopatisi ile ilişkili fasyal adezyona bağlı gerilmesi sonucu oluşur.…”

Lateral Femoral Cutaneous Nerve Entrapment

“…61.7 ) [ 27 ]. This angle increases with movement and hip extension; however, hip fl exion and abduction as seen in the lithotomy position does not increase strain on the LFCN [ 10 ]. The tendency for entrapment at the path between the pelvis and thigh, as well as in the thigh itself, is exacerbated by obesity, pregnancy, ascites, tight garments, seat belts, braces, direct trauma, leg length changes, scoliosis, and muscle spasm [ 25 ].…”