title: Postoperative Delayed Cervical Palsies: Understanding the Etiology.
abstract: METHODS
  Retrospective study.
  
  
  OBJECTIVE
  This study reviews 1,768 consecutive cervical decompressions with or without instrumented fusion to identify patient-specific and procedural risk factors significantly correlated with the development of delayed cervical palsy (DCP).
  
  
  METHODS
  Baseline demographic and procedural information was collected from the electronic medical record. Particular attention was devoted to reviewing each chart for recognized risk factors of postsurgical inflammatory neuropathy: autoimmune disease, blood transfusions, diabetes, and smoking.
  
  
  RESULTS
  Of 1,669 patients, 56 (3.4%) developed a DCP. Although 71% of the palsies involved C5, 55% of palsies were multimyotomal and 18% were bilateral. Significant risk factors on univariate analysis included age (p = 0.0061, odds ratio [OR] = 1.07, 95% confidence interval [CI] 1.008 to 1.050), posterior instrumented fusion (p < 0.0001, OR = 3.30, 95% CI 1.920 to 5.653), prone versus semisitting/sitting position (p = 0.0036, OR = 3.58, 95% CI 1.451 to 11.881), number of operative levels (p < 0.0001, OR = 1.42, 95% CI 1.247 to 1.605), intraoperative transfusions (p = 0.0231, OR = 2.57, 95% CI 1.152 to 5.132), and nonspecific autoimmune disease (p = 0.0107, OR = 3.83, 95% CI 1.418 to 8.730). On multivariate analysis, number of operative levels (p = 0.0053, OR = 1.27, 95% CI 1.075 to 1.496) and nonspecific autoimmune disease (p = 0.0416, OR 2.95, 95% CI 1.047 to 7.092) remained significant.
  
  
  CONCLUSIONS
  Although this study partially supports a mechanical etiology in the pathogenesis of a DCP, we also describe a notable correlation with autoimmune risk factors. Bilateral and multimyotomal involvement provides additional support that some DCPs may result from an inflammatory response and thus an underlying multifactorial etiology for this complication.
authors.affiliation: Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota, United States.
authors.forename: Ryan F
authors.initials: RF
authors.lastname: Planchard
authors.affiliation: Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota, United States.
authors.forename: Patrick R
authors.initials: PR
authors.lastname: Maloney
authors.affiliation: Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota, United States.
authors.forename: Grant W
authors.initials: GW
authors.lastname: Mallory
authors.affiliation: Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota, United States.
authors.forename: Ross C
authors.initials: RC
authors.lastname: Puffer
authors.affiliation: Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota, United States.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Spinner
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, United States.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Nassr
authors.affiliation: Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota, United States.
authors.forename: Jeremy L
authors.initials: JL
authors.lastname: Fogelson
authors.affiliation: Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota, United States.
authors.forename: William E
authors.initials: WE
authors.lastname: Krauss
authors.affiliation: Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota, United States.
authors.forename: Michelle J
authors.initials: MJ
authors.lastname: Clarke
keywords: autoimmune; cervical spine; etiology; inflammatory neuropathy; postoperative C5 palsy