title: Intraoperative nerve monitoring during total shoulder arthroplasty surgery.
abstract: BACKGROUND
  Nerve injury is an acknowledged complication of total shoulder arthroplasty (TSA). Although the incidence of postoperative neurological deficit has been reported to be between 1% and 16%, the true incidence of nerve damage is considered to be higher. The present study aimed to identify the rate of intraoperative nerve injury during total shoulder arthroplasty and to determine potential risk factors.
  
  
  METHODS
  A prospective study of nerve conduction in 21 patients who underwent primary or revision TSA was carried out over a 12-month period. Nerve conduction was monitored by measuring intraoperative sensory evoked potentials (SEP). A significant neurophysiological signal change was defined as either a unilateral or bilateral decrease in SEP signal of ≥50%, a latency increase of ≥10% or a change in waveform morphology, not caused by operative or anaesthetic technique.
  
  
  RESULTS
  Seven (33%) patients had a SEP signal change. The only significant risk factor identified for signal change was male sex (odds ratio 15.00, 95% confidence interval). The median nerve was the most affected nerve in the operated arm. All but one signal change returned to normal before completion of the operation and no patient had a persisting postoperative clinical neurological deficit.
  
  
  CONCLUSIONS
  The incidence of intraoperative nerve damage may be more common than previously reported. However, the loss of SEP signal is reversible and does not correlate with persisting clinical neurological deficits. The median nerve appears to be most at risk. Monitoring SEPs in the operated limb during TSA may be a valuable tool during TSA.
authors: Royal National Orthopaedic Hospital, London, UK.
authors: Atif A
authors: AA
authors: Malik
authors: Royal National Orthopaedic Hospital, London, UK.
authors: Nick
authors: N
authors: Aresti
authors: Royal National Orthopaedic Hospital, London, UK.
authors: Karen
authors: K
authors: Plumb
authors: Royal National Orthopaedic Hospital, London, UK.
authors: Joseph
authors: J
authors: Cowan
authors: Royal National Orthopaedic Hospital, London, UK.
authors: Deborah
authors: D
authors: Higgs
authors: Royal National Orthopaedic Hospital, London, UK.
authors: Simon
authors: S
authors: Lambert
authors: Royal National Orthopaedic Hospital, London, UK.
authors: Mark
authors: M
authors: Falworth
keywords: Intraoperative nerve monitoring; nerve injury; shoulder arthroplasty