Conference News Update—American Association of Neurological Surgeons

The optimal thresholds, prognostic significance, and clinical correlations of ICP and PRx are likely to be time-dependent, he added.

How Common Is Position-Related Neuropraxia In Spine Surgery?

Gurpreet Surinder Gandhoke, MD, a neurosurgeon in Pittsburgh, and colleagues examined the incidence of position-related neuropraxia in 4,489 consecutive patients undergoing spine surgery at a university hospital. Some patients in the group had peripheral nerve injury from positioning. The authors observed intraoperative monitoring (IOM) changes related to arm and leg positioning and calculated their sensitivity and specificity in predicting the development of a new position-related peripheral nerve injury. Impact of length of surgery and other variables, including age, sex, BMI, diabetes, hypertension, coronary artery disease, cardiovascular disease, and a history of smoking on the development of a new peripheral nerve injury were defined.

Patients were in the following positions: arms abducted and flexed at the elbow (64.7%), arms tucked at the side (35%), and the lateral position (0.3%). Thirteen of 4,489 patients developed a new positioning-related peripheral nerve deficit, 54% developed meralgia paresthetica, and 46% developed ulnar neuropathy.

Seventy-two patients (1.6%) developed IOM changes from positioning, and all of these patients underwent a repositioning maneuver. One of these 72 patients (1.3%) developed a new position-related nerve deficit. Of the 98.4% of patients who did not develop position-related IOM changes, 0.3% developed a new position-related nerve deficit.

Sensitivity of IOM to detect a new position-related nerve deficit was 7.69%, and the specificity was 98.41%. Neither length of surgery nor any analyzed patient-related variable significantly affected the development of a new neuropraxia. The incidence of a new position-related nerve deficit in spine surgery was less than 0.3%. IOM had high specificity and low sensitivity in detecting a positioning-related deficit.