title: The Effect of Smoking on Spinal Cord Healing Following Surgical Treatment of Cervical Myelopathy.
abstract: METHODS
  Retrospective cohort.
  
  
  OBJECTIVE
  The purpose of this study was to compare outcomes of surgical treatment of cervical myelopathy between smokers and nonsmokers as assessed by the Nurick score.
  
  
  BACKGROUND
  The harmful effects of smoking on healing have been well established. However, the effect of smoking on postoperative outcomes for cervical myelopathy has not been specifically evaluated.
  
  
  METHODS
  The medical records of 212 patients who underwent surgery for cervical spondylotic myelopathy were reviewed. Inclusion criteria were the diagnosis of cervical spondylotic myelopathy with a Nurick score, surgical intervention, and at least 2 years of follow-up. The patients were categorized into 2 groups according to smoking status and stratified according to pack years and packs per day. Age at presentation, sex, preoperative and postoperative Nurick score, duration of symptoms preoperatively, duration of follow-up, procedure performed, surgical approach, number of levels fused, diabetes status, cocaine use, ethanol use, preoperative magnetic resonance imaging signal change, and whether the patient belonged to the Veterans Administration (VA) were recorded. Analysis was done using simple linear regression and multiple regression.
  
  
  RESULTS
  Univariate analysis demonstrated a postoperative improvement in nonsmokers of 1.53 points on the Nurick scale compared with 0.6 points in smokers (P < 0.001). There is a progressive decrease in improvement as the number of pack years and packs per day increase (P < 0.001). There is a greater improvement in Nurick score with greater (worse) preoperative score but only in patients with fewer than 25 pack years. Smoking status is not associated with preoperative Nurick score.
  
  
  CONCLUSIONS
  Smoking status is associated with poor improvement in Nurick score after surgical treatment of cervical myelopathy. Smoking may have a directly toxic effect on the intrinsic healing capability of the spinal cord, particularly beyond 25 pack years.
  
  
  METHODS
  3.
authors.affiliation: *Case Western Reserve University School of Medicine, Cleveland, OH †New Hampshire Neurospine Institute, Bedford, NH; and ‡Department of Orthopaedic Surgery, University Hospitals Case Medical Center, Cleveland, OH.
authors.forename: David J
authors.initials: DJ
authors.lastname: Kusin
authors.forename: Uri M
authors.initials: UM
authors.lastname: Ahn
authors.forename: Nicholas U
authors.initials: NU
authors.lastname: Ahn
mesh_terms: D002574:Cervical Vertebrae / Q000503:physiopathology / Q000601:surgery*; D019299:Decompression, Surgical / Q000009:adverse effects* / Q000295:instrumentation; D006801:Humans; D007796:Laminectomy / Q000009:adverse effects* / Q000295:instrumentation; D065406:Laminoplasty / Q000009:adverse effects* / Q000295:instrumentation; D016014:Linear Models; D008499:Medical Records; D015999:Multivariate Analysis; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D013116:Spinal Cord / Q000503:physiopathology / Q000601:surgery*; D013118:Spinal Cord Diseases / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D013123:Spinal Fusion / Q000009:adverse effects* / Q000295:instrumentation; D013997:Time Factors; D016896:Treatment Outcome; D014945:Wound Healing