title: A Novel Scoring System Associated With Surgical Outcome of Distal-type Cervical Spondylotic Amyotrophy.
abstract: METHODS
  A single-center retrospective study.
  
  
  OBJECTIVE
  To elucidate the pathology of distal-type cervical spondylotic amyotrophy (CSA) and to assess predictive factors and a novel scoring system associated with surgical outcome.
  
  
  BACKGROUND
  Because of its rarity, the pathophysiology and surgical outcome of distal-type CSA are less well understood compared with proximal-type CSA.
  
  
  METHODS
  Surgical procedures were performed in 13 patients with distal-type CSA. Patients were classified into 2 groups: those with good recovery of muscle power (group 1, n=4) and those with fair recovery (group 2, n=9). All patients underwent magnetic resonance imaging. Central motor conduction time was recorded in abductor digit minim and compound muscle action potentials (CMAPs) were recorded in extensor carpi dig. Predictive factors associated with surgical outcome and a scoring system based on clinical, radiologic, and electrophysiological findings were evaluated. Twelve of 13 patients were scored for the following features: (1) duration of symptoms ≥13 months, (2) initial manual muscle testing ≤1, (3) multiple compressions in magnetic resonance imaging, (4) CMAPs amplitudes on affected side <1 mV, (5) CMAPs amplitudes on normal side <7.2 mV, (6) central motor conduction time longer than 7.4 ms, (7) the ratio of CMAPs amplitudes comparison with the normal side <50%.
  
  
  RESULTS
  At final follow-up, 2 patients were graded excellent, 2 good, 9 fair, and 0 poor. None of the predictive factors was significantly different between groups 1 and 2. The mean score in group 2 (5.12±1.12) was significantly higher than for group 1 (2±1.15; P=0.006). Although all 8 patients in group 2 scored ≥4 points, all 4 patients in group 1 scored ≤3.
  
  
  CONCLUSIONS
  Comprehensive assessment using a scoring system is useful for predicting the surgical outcome of distal-type CSA. Surgeons should be aware that a score of ≥4 points correlates with poor surgical outcome on motor function.
authors.affiliation: Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Funaba
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Kanchiku
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Imajo
authors.forename: Hidenori
authors.initials: H
authors.lastname: Suzuki
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Norihiro
authors.initials: N
authors.lastname: Nishida
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Fujimoto
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Taguchi
mesh_terms: D000200:Action Potentials; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009133:Muscular Atrophy / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D012107:Research Design; D055009:Spondylosis / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome