ULNAR NEUROPATHY - INCIDENCE, OUTCOME, AND RISK-FACTORS IN SEDATED ORANESTHETIZED PATIENTS

Background: Ulnar neuropathy is well-recognized as a potential complic ation of procedures performed on anesthetized patients. However, repor ted outcomes and risk factors for this problem are based on small seri es and anecdotes. Methods: We retrospectively reviewed the perioperati ve courses of 1,129,692 consecutive patients who underwent diagnostic and noncardiac surgical procedures with concurrent anesthetic manageme nt at the Mayo Clinic from 1957 through 1991 (inclusive). The medical diagnoses of patients who had these procedures were scanned for 26 dia gnoses associated with neuropathy. Persistent neuropathy of an ulnar n erve was defined as a sensory or motor deficit of greater than 3 month s' duration. Risk factors anecdotally associated with persistent neuro pathy were analyzed by comparing patients with an ulnar neuropathy wit h control subjects in a 1:3 case-control study. Results:Persistent uln ar neuropathies were identified in 414 patients, a rate of 1 per 2,729 patients. Of these, 38 (9%) patients had bilateral neuropathies. Appr oximately equal numbers of the neuropathies included sensory loss only or mixed sensory and motor loss. Initial symptoms for most neuropathi es were noted more than 24 h after the procedure. Factors associated w ith persistent ulnar neuropathy included male gender and a duration of hospitalization of more than 14 days (P < 0.01). Neuropathy was more likely to develop in very thin and obese patients than in patients wit h average body habitus. Neither the type of anesthetic technique nor t he patient position was found to be associated with this neuropathy. O f the 382 patients who survived the Ist postoperative yr, 53% regained complete motor function and sensation and were asymptomatic. Of those with neuropathies persisting for more than 1 yr, most had moderate or greater disability from pain or weakness. Conclusions: These data sug gest that perioperative ulnar neuropathies are associated with factors other than general anesthesia and intraoperative positioning. Men at the extremes of body habitus who have prolonged hospitalizations are p articularly susceptible to development of ulnar neuropathies.