title: Progressive Myelopathy Patients Who Lack Spinal Cord Monitoring Data Have the Highest Rate of Spinal Cord Deficits Following Posterior Vertebral Column Resection Surgery.
abstract: OBJECTIVE
  The authors analyzed patients who underwent posterior vertebral column resection (PVCR). All patients had spinal cord monitoring (SCM) attempted but some did not have predictable and usable tracings.
  
  
  BACKGROUND
  Posterior vertebral column resection is a powerful technique to correct severe spinal deformities but it has the potential for major neurologic complications. Spinal cord monitoring is extremely helpful in managing these difficult patients.
  
  
  METHODS
  Spinal cord monitoring data, operative reports, charts, and radiographs of 112 consecutive adult and pediatric patients (mean age, 23.5 years; range, 5.8-74.0 years) who underwent PVCR were reviewed. All surgical procedures were performed between 2002 and 2010 by 1 surgeon at a single institution.
  
  
  RESULTS
  Twenty patients (11 male, 9 female; mean age, 15.9 years) of 112 (17.9%) did not have detectable SCM tracings during surgery. Average preoperative and postoperative scoliosis for these 20 patients was 79.2° and 41.3°, respectively. Average preoperative and postoperative kyphosis was 106.6° and 59.8°, respectively. Thirteen of the 20 were revisions. Preoperative neurologic status included acute progressive myelopathy (n = 9), no lower extremity function (n = 6), chronic weak lower extremities (n = 2), chronic quadriparesis (n = 1), and normal (n = 2). Four of 9 patients with acute progressive myelopathy developed transient paraplegia postoperatively. They had angular kyphosis (mean, 116.3°) and 3 were revisions. Compared with the 92 patients who had obtainable intraoperative SCM and no spinal cord deficits, the risk of developing postoperative paraplegia in patients who had no SCM tracings was statistically higher (p = .0008). All 4 with spinal cord deficits after surgery regained varying degrees of lower extremity function and resumed ambulatory status at most recent follow-up.
  
  
  CONCLUSIONS
  The prevalence of unobtainable intraoperative SCM during PVCR was 17.9% (20 of 112). Postoperative transient paraplegia occurred exclusively in patients with no monitorable data as a result of angular kyphosis with acute progressive myelopathy. The rate of transient spinal cord deficits was significantly higher when there was no obtainable SCM (4 of 20 vs. 0 of 92 with SCM; p = .0008).
authors.affiliation: Department of Orthopaedic Surgery, Icahn School of Medicine at Mount Sinai, 5 East 98th Street, Box 1188, New York, NY 10029, USA.
authors.forename: Samuel K
authors.initials: SK
authors.lastname: Cho
authors.affiliation: Department of Orthopaedic Surgery, Washington University School of Medicine, 660 S. Euclid Avenue, Campus Box 8233, St. Louis, MO 63110, USA. Electronic address: lenkel@wudosis.wustl.edu.
authors.forename: Lawrence G
authors.initials: LG
authors.lastname: Lenke
authors.affiliation: Intraoperative Monitoring Service, Barnes-Jewish Hospital, One Barnes-Jewish Hospital Plaza, St. Louis, MO 63110, USA.
authors.forename: Shelly M
authors.initials: SM
authors.lastname: Bolon
authors.affiliation: Regions Hospital, 640 Jackson St., St. Paul, MN 55101, USA.
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Kang
authors.affiliation: Department of Orthopaedic Surgery, Washington University School of Medicine, 660 S. Euclid Avenue, Campus Box 8233, St. Louis, MO 63110, USA.
authors.forename: Lukas P
authors.initials: LP
authors.lastname: Zebala
authors.affiliation: Department of Orthopaedic Surgery, Albert Einstein Medical Center, 5501 Old York Rd./WCB 4, Philadelphia, PA 19141, USA.
authors.forename: Joshua M
authors.initials: JM
authors.lastname: Pahys
authors.affiliation: Department of Orthopaedic Surgery, Albert Einstein College of Medicine, Montefiore University Hospital, 3400 Bainbridge Ave, 6th Fl., New York, NY 10461, USA.
authors.forename: Woojin
authors.initials: W
authors.lastname: Cho
authors.affiliation: Department of Orthopaedic Surgery, Washington University School of Medicine, 660 S. Euclid Avenue, Campus Box 8233, St. Louis, MO 63110, USA.
authors.forename: Linda A
authors.initials: LA
authors.lastname: Koester
keywords: Complications; Myelopathy; Paraplegia; Spinal cord monitoring; Vertebral column resection