title: Prognosis of Significant Intraoperative Neurophysiologic Monitoring Events in Severe Spinal Deformity Surgery.
abstract: Intraoperative neurophysiologic monitoring has become a standard tool for mitigating neurologic injury during spinal deformity surgery. Significant monitoring changes during deformity correction are relatively uncommon. This study characterizes precipitating factors for neurologic injury and relates significant events and postoperative neurologic prognosis.
  
  
  
  All spinal deformity surgeries at a West African hospital over a 12-month period were reviewed. Patients were included if complete operative reports, monitoring data, and postoperative neurologic examinations were available for review. Surgical and systemic triggers of monitoring events were recorded and neurologic status was followed for 6 weeks postoperatively.
  
  
  
  Eighty-eight patients met inclusion criteria. The average age was 14 years (3-28). The average kyphosis was 108° (54°-176°) and average scoliosis was 100° (48°-177°). There were 44 separate neurologic events in 34 patients (39%). The most common triggers were traction or positioning (16), posterior column osteotomies/vertebral column resections (9/1), and distraction, corrective maneuvers, or implant placement (12). On surgery completion, 100% (12/12) of events from non-osteotomy-related surgical procedures, 75% (12/16) of events from traction or positioning resolved; however, 0% (0/10) of events from osteotomies resolved completely. Eight percent (7/88) had new neurologic deficits postoperatively, all with intraoperative monitoring changes. In 6 of these 7 patients, the event was attributed to an osteotomy; in 1 patient the cause was not determined. At 6-week follow-up, all patients had some preserved motor function bilaterally with the ability to walk (ASIA D/E) or recovered completely.
  
  
  
  Intraoperative signal changes were most frequently from traction or positioning. However, the most common cause of persistent neurologic deterioration and the only cause of postoperative neurologic deficit was the performance of osteotomies. Unlike traction- or instrument-related correction, osteotomies produce irreversible changes, from canal intrusion or sudden localized deformity change. The incidence of postoperative neurologic deficit is very low when the inciting cause is reversed; however, osteotomy-related events are irreversible, with a high incidence of associated lasting neurologic injury.
authors.affiliation: Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021, USA. Electronic address: benjamin.t.bjerke@gmail.com.
authors.forename: Benjamin T
authors.initials: BT
authors.lastname: Bjerke
authors.affiliation: FOCOS Hospital, P.O. Box KD 779 Kanda, Accra, Ghana, Africa.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Zuchelli
authors.affiliation: Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021, USA.
authors.forename: Venu M
authors.initials: VM
authors.lastname: Nemani
authors.affiliation: Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021, USA.
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Emerson
authors.affiliation: Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021, USA.
authors.forename: Han Jo
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: FOCOS Hospital, P.O. Box KD 779 Kanda, Accra, Ghana, Africa.
authors.forename: Oheneba
authors.initials: O
authors.lastname: Boachie-Adjei
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D064795:Intraoperative Neurophysiological Monitoring / Q000706:statistics & numerical data*; D007738:Kyphosis / Q000601:surgery; D008297:Male; D019635:Neurosurgical Procedures / Q000009:adverse effects* / Q000379:methods; D010027:Osteotomy / Q000009:adverse effects* / Q000379:methods; D011183:Postoperative Complications / Q000175:diagnosis* / Q000209:etiology; D011379:Prognosis; D011446:Prospective Studies; D012600:Scoliosis / Q000601:surgery; D013131:Spine / Q000002:abnormalities* / Q000601:surgery; D055815:Young Adult
keywords: Complications; Intraoperative neurophysiologic monitoring; Nerve injury; Spinal cord injury; Spinal deformity