title: Multimodal nerve monitoring during periacetabular osteotomy identifies surgical steps associated with risk of injury.
abstract: Sciatic nerve palsy after periacetabular osteotomy (PAO) is a serious complication. The purpose of this study was to determine whether a multimodal sciatic monitoring technique allows for identification of surgical steps that place the sciatic nerve at risk.
  
  
  
  Transcranial electrical motor evoked potentials (TcMEPs), somatosensory evoked potentials (SSEPs), and spontaneous electromyography (EMG) were monitored in a consecutive series of 34 patients (40 hips) who underwent PAO for the treatment of symptomatic hip dysplasia between January 2012 and November 2014. There were 29 females (85%) and five males (15%) with an average age of 19 years (range, 12-36 years) at the time of surgery.
  
  
  
  We detected eight temporary sciatic nerve monitoring alerts in six patients (incidence of 15%). The events included decrease in amplitude of the TcMEPs related to the position of the hip during incomplete ischium osteotomy and placement of a retractor in the sciatic notch during the posterior column osteotomy (N = 3), generalized bilateral decrease in TcMEPs during fragment manipulation and fixation in association with acute blood loss (N = 2), and a change in SSEPs during a superior pubic osteotomy and supra-acetabular osteotomy (N = 1). At the end of the procedure, TcMEPs and SSEPs were at baseline and there was no abnormal pattern on EMG in all patients. Post-operatively, at two, six, 12 weeks, and six and 12 months, no motor weakness or sensory deficits were noted.
  
  
  
  Multimodal neuromonitoring allowed for identification of intra-operative steps and maneuvers that potentially place the sciatic nerve at higher risk of injury.
authors.affiliation: Department of Orthopaedic Surgery, Boston Children's Hospital, 300 Longwood Ave, Hunnewell Building, Boston, MA, 02215, USA. Eduardo.Novais@childrens.harvard.edu.
authors.forename: Eduardo N
authors.initials: EN
authors.lastname: Novais
authors.affiliation: Department of Orthopaedic Surgery, Children's Hospital Colorado, University of Colorado School of Medicine, 13123 East 16th Avenue, B060, Aurora, CO, 80045, USA.
authors.forename: Travis
authors.initials: T
authors.lastname: Heare
authors.affiliation: Musculoskeletal Research Center, Department of Orthopaedic Surgery, Children's Hospital Colorado, 13123 East 16th Avenue, B060, Aurora, CO, 80045, USA.
authors.forename: Lauryn
authors.initials: L
authors.lastname: Kestel
authors.affiliation: Department of Anesthesiology, Children's Hospital Colorado, 13123 East 16th Avenue, B090, Aurora, CO, 80045, USA.
authors.forename: Patricia
authors.initials: P
authors.lastname: Oliver
authors.affiliation: Department of Anesthesiology, Children's Hospital Colorado, 13123 East 16th Avenue, B090, Aurora, CO, 80045, USA.
authors.forename: Willy
authors.initials: W
authors.lastname: Boucharel
authors.affiliation: Department of Orthopaedic Surgery, Children's Hospital Colorado, University of Colorado School of Medicine, 13123 East 16th Avenue, B060, Aurora, CO, 80045, USA.|Musculoskeletal Research Center, Department of Orthopaedic Surgery, Children's Hospital Colorado, 13123 East 16th Avenue, B060, Aurora, CO, 80045, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Koerner
authors.affiliation: Department of Anesthesiology, Children's Hospital Colorado, 13123 East 16th Avenue, B090, Aurora, CO, 80045, USA.
authors.forename: Kim
authors.initials: K
authors.lastname: Strupp
mesh_terms: D000077:Acetabulum / Q000601:surgery; D000293:Adolescent; D000328:Adult; D002648:Child; D004576:Electromyography / Q000379:methods*; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006618:Hip Dislocation, Congenital / Q000601:surgery; D006801:Humans; D015994:Incidence; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods; D010027:Osteotomy / Q000009:adverse effects* / Q000379:methods; D012189:Retrospective Studies; D012584:Sciatic Nerve / Q000293:injuries / Q000503:physiopathology*; D020426:Sciatic Neuropathy / Q000175:diagnosis* / Q000209:etiology; D055815:Young Adult
keywords: Adolescent; Hip dysplasia; Neuromonitoring; PAO; Sciatic nerve palsy