title: Somatosensory evoked potentials help prevent positioning-related brachial plexus injury during skull base surgery.
abstract: OBJECTIVE
  Evaluate the use of somatosensory evoked potentials (SSEP) monitoring to detect positioning-related brachial plexus injury during skull base surgery.
  
  
  METHODS
  Prospective cohort observational study.
  
  
  METHODS
  University Hospital.
  
  
  METHODS
  Patients undergoing skull base surgery had a focused neurologic exam of the brachial plexus performed before and after surgery. Under stable anesthesia, brachial plexus SSEP values were obtained before and after surgical positioning. Significant SSEP changes required a readjustment of arm or neck positions. SSEPs were assessed every 30 minutes. If changes were noted, position was readjusted and SSEPs were reassessed until surgical completion. Demographic data, neurologic exams, SSEP latency, and amplitude values were recorded. Persistent changes were correlated with postoperative neurologic findings.
  
  
  RESULTS
  Sixty-five patients, 15 to 77 years old, were studied. Six patients (9.2%) developed SSEP amplitude changes after positioning (average amplitude decrease 72.8%). One patient had a significant latency increase. The sensitivity of SSEP for detection of injury was 57%, while specificity was 94.7%. The average body mass index (BMI) of patients with normal and abnormal SSEPs was 28.7 ± 5.6 versus 29.2 ± 8.0, respectively. Average BMI of patients with postoperative symptoms regardless of SSEP findings was 33.8 ± 4.3. Two patients who had persistent SSEP changes after positioning had BMIs of 40.1 and 31.2 kg/m(2), respectively. Improvement in neurologic findings occurred in all patients after surgery.
  
  
  CONCLUSIONS
  This study demonstrates that upper extremity nerve stress can be detected in real time using SSEP and may be of value in protecting patients from nerve injury undergoing lateral skull base surgery.
authors.affiliation: Department of Anesthesiology, Loyola University Medical Center, Maywood, Illinois 60153, USA. wjellis@lumc.edu
authors.forename: W Scott
authors.initials: WS
authors.lastname: Jellish
authors.forename: Gazenfer
authors.initials: G
authors.lastname: Sherazee
authors.forename: Jagruti
authors.initials: J
authors.lastname: Patel
authors.forename: Renato
authors.initials: R
authors.lastname: Cunanan
authors.forename: Janet
authors.initials: J
authors.lastname: Steele
authors.forename: Konstantin
authors.initials: K
authors.lastname: Garibashvilli
authors.forename: Maria
authors.initials: M
authors.lastname: Baldwin
authors.forename: Douglas
authors.initials: D
authors.lastname: Anderson
authors.forename: John P
authors.initials: JP
authors.lastname: Leonetti
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001917:Brachial Plexus / Q000293:injuries*; D015331:Cohort Studies; D005073:Evoked Potentials, Somatosensory; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D056888:Patient Positioning / Q000009:adverse effects*; D059348:Peripheral Nerve Injuries / Q000175:diagnosis* / Q000209:etiology / Q000517:prevention & control; D012680:Sensitivity and Specificity; D019292:Skull Base Neoplasms / Q000503:physiopathology / Q000601:surgery*; D055815:Young Adult
keywords: SSEP monitoring; brachial plexus; injury; skull base surgery