Bilateral Iatrogenic Femoral Neuropathy

Dear Editor, Postoperative femoral neuropathy is an uncommon complication associated with pelvic/abdominal surgery. The main mechanism underlying this neuropathy is stretching and/or prolonged compression of the nerve.1,2 The nerve compression can be caused by the self-retaining retractors that are sometimes used during surgery directly constricting the nerve against the pelvic sidewall and inducing ischemia.1 Symptoms of femoral neuropathy are weakness of ipsilateral hip flexion and knee extension, and sensory deficit on the anteromedial thigh. The prognosis is generally good, with partial or complete recovery being common. Postoperative femoral neuropathy is generally unilateral2-4; bilateral postoperative femoral neuropathy appears to be very rare.5,6 Herein we report a case of bilateral femoral nerve neuropathy that occurred in a patient undergoing abdominal surgery. A thin 44-year-old woman was diagnosed with rectosigmoid cancer and underwent a Hartmann surgical procedure, which involves resection of the rectosigmoid colon with creation of a colostomy bag. The presurgery general and neurological visits did not disclose any unexpected abnormalities. She had previously been physically healthy, with no underlying diseases such as hypertension, diabetes mellitus, or peripheral neuropathy. During the surgery, she was placed in a lithotomy position and a bilateral self-retaining retractor was used to facilitate the exploration of the surgical field. The surgery took about 2 hours. During recovery from the anesthesia, the patient complained of hypoesthesia over the anteromedial side of both thighs and proximal weakness in both lower limbs; in the immediate postoperative period she could neither stand nor get out of bed. A neurological examination revealed bilateral weakness of the knee extensor and hip flexor, hypoesthesia in the anteromedial thigh, and bilateral patellar areflexia. Muscle strength was assessed on both legs on the Medical Research Council scale: the iliopsoas and quadriceps muscles scored 2/5, while the adductor, hamstrings, and tibialis anterior muscles scored 5/5. An extensive diagnostic work-up was negative for abnormalities. Neurophysiological studies performed a few days after the onset of symptoms revealed bilateral femoral neuropathy (Table 1). The patient underwent physical therapy. At a 6-month follow-up the patient had only partially regained sensory and motor functions; she was able to walk with a double cane. Electromyography performed 1 year after symptom onset demonstrated persistent bilateral femoral nerve neuropathy. The femoral nerve originates from the posterior division of the ventral branch of the second to fourth lumbar roots behind the psoas muscle; it passes in the groove between the psoas and iliac muscles and descends into the thigh beneath the inguinal ligament. The pathophysiology of the nerve injury in abdominal/pelvic surgery includes compression, stretch, ischemia, and ileopsoas hematoma.1,2 The injury is often caused by the use of a selfretraining retractor directly compressing the nerve against the abdominal wall as it courses through the body of the psoas muscle, or compression of the iliac vessels, causing ischemia Valeria Bono Vincenzo La Bella Rossella Spataro