title: Preoperative spinal cord damage affects the characteristics and prognosis of segmental motor paralysis after cervical decompression surgery.
abstract: METHODS
  Retrospective analysis.
  
  
  OBJECTIVE
  To test the hypothesis that preoperative spinal cord damage affects postoperative segmental motor paralysis (SMP).
  
  
  BACKGROUND
  SMP is an enigmatic complication after cervical decompression surgery. The cause of this complication remains controversial. We particularly focused on preoperative T2-weighted high signal change (T2HSC) on magnetic resonance imaging in the spinal cord, and assessed the influence of preoperative T2HSC on SMP after cervical decompression surgery.
  
  
  METHODS
  A retrospective review of 181 consecutive patients (130 males and 51 females) who underwent cervical decompression surgery was conducted. SMP was defined as development of postoperative motor palsy of the upper extremities by at least 1 grade in manual muscle testing without impairment of the lower extremities. The relationship between the locations of T2HSC in preoperative magnetic resonance imaging and SMP and Japanese Orthopedic Association score was investigated.
  
  
  RESULTS
  Preoperative T2HSC was detected in 78% (142/181) of the patients. SMP occurred in 9% (17/181) of the patients. Preoperative T2HSC was not a significant risk factor for the occurrence of SMP (P = 0.682). However, T2HSC significantly influenced the severity of SMP: the number of paralyzed segments increased with an incidence rate ratio of 2.2 (P = 0.026), the manual muscle score deteriorated with an odds ratio of 8.4 (P = 0.032), and the recovery period was extended with a hazard ratio of 4.0 (P = 0.035). In patients with preoperative T2HSC, Japanese Orthopaedic Association scores remained lower than those in patients without T2HSC throughout the entire period including pre- and postoperative periods (P < 0.001).
  
  
  CONCLUSIONS
  Preoperative T2HSC was associated with worse severity of SMP in patients who underwent cervical decompression surgery, suggesting that preoperative spinal cord damage is one of the pathomechanisms of SMP after cervical decompression surgery.
  
  
  METHODS
  3.
authors.affiliation: *Department of Orthopaedic Surgery, Shinshu University, School of Medicine, Matsumoto, Japan; and †Spine Center, Yodakubo Hospital, Nagawa, Nagano, Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Ikegami
authors.forename: Takahiro
authors.initials: T
authors.lastname: Tsutsumimoto
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohta
authors.forename: Mutsuki
authors.initials: M
authors.lastname: Yui
authors.forename: Hidemi
authors.initials: H
authors.lastname: Kosaku
authors.forename: Masashi
authors.initials: M
authors.lastname: Uehara
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Misawa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002574:Cervical Vertebrae / Q000473:pathology / Q000601:surgery*; D019299:Decompression, Surgical / Q000009:adverse effects*; D005260:Female; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D016017:Odds Ratio; D019637:Orthopedic Procedures / Q000009:adverse effects*; D010243:Paralysis / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology / Q000523:psychology; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D013118:Spinal Cord Diseases / Q000150:complications / Q000175:diagnosis / Q000601:surgery*; D016896:Treatment Outcome; D034941:Upper Extremity / Q000294:innervation*