Peripheral nerve injury is a common complication of gynecologic surgery. It can result from improper positioning of patients and retractors. The objective of this video is to demonstrate the anatomy of the brachial, lumbar, and sacral nerve plexuses with cadaver dissections, live models and surgical videos, and to illustrate the possible mechanisms of nerve injuries and how they may be prevented.
Cadaver dissections were performed of the brachial, lumbar, and sacral nerve plexuses. The dissected specimens were placed in positions commonly used during gynecologic surgery (Trendelenburg, lithotomy in Allen or candy-cane stirrups, extended or tucked arms) to illustrate sites and mechanisms by which nerve injury may occur. Self-retaining retractors were placed to show femoral nerve compression and proper use of retractors. Live models and video clips from surgical cases were used to illustrate proper patient positioning.
The brachial plexus (C4-T1) can be injured by compression against shoulder braces with the patient in Trendelenburg position or by stretching with arm abduction >90 degrees. Symptoms of radial nerve injury include sensory loss over the dorsal hand and motor paralysis (wrist drop). The ulnar nerve (C8-T1) is susceptible to compression as it passes across the elbow. The arm should be pronated prior to tucking it to the side and supinated if the arm is abducted. Injury results in paresthesia, inability to abduct and adduct the digits, and claw hand. The femoral nerve (L2-L4) can be compressed under the psoas muscle when improperly sized retractor blades are used. It can also be compressed under the inguinal ligament during lithotomy position if the hip is excessively flexed, over-abducted, or externally rotated. Injury results in numbness of the anteriomedial thigh and medial calf, and inability to flex the hip and extend the knee. The patellar reflex is usually absent and the knee buckles when the patient attempts ambulation. The sciatic nerve (L4-S3) is susceptible to stretch injury during lithotomy position if the hips are hyperflexed, excessively abducted or externally rotated. Injury results in sensory loss over the lateral leg and whole foot, weak plantar and dorsiflexion of the foot, weak knee flexion, and loss of ankle jerk. The common peroneal nerve (L4-S2) is susceptible to compression as it wraps around the lateral side of the fibular neck. Care should be taken to avoid compression of the nerve when using Allen or candy-cane stirrups. The surgical assistant should avoid leaning on the patient's leg, which may compress the fibula against the stirrup. Injury results in sensory loss over the lateral and dorsal foot, and inability to dorsiflex and evert the foot (foot drop).
A comprehensive knowledge of anatomy, patient positioning, and use of retractors should minimize the risk of peripheral nerve injury during gynecologic surgery. Early signs of injury should prompt appropriate consultation and initiation of therapy. This video demonstrates the anatomy and mechanisms of injury in cadavers, live models and surgical patients.