title: Pathology and prognosis of proximal-type cervical spondylotic amyotrophy: new assessment using compound muscle action potentials of deltoid and biceps brachii muscles.
abstract: METHODS
  Case studies of patients with cervical spondylotic amyotrophy (CSA) used compound muscle action potentials (CMAPs) of deltoid and biceps brachii muscles.
  
  
  OBJECTIVE
  To discuss pathology and prognosis from the magnetic resonance imaging (MRI) and CMAPs of deltoid and biceps brachii muscles.
  
  
  BACKGROUND
  CSA is a rare type of cervical spondylotic disorder. Selective lesions in ventral nerve roots (VNR) or anterior horns (AH) have been proposed to explain the pathology of CSA, but these are not well understood.
  
  
  METHODS
  Conservative therapy was performed in 21 patients with the proximal-type CSA. Patients were classified into two groups: 13 with incomplete recovery of deltoid and biceps brachii muscle strength (Group 1) and 8 with complete recovery (Group 2). All underwent MRI. Erb-point-stimulated CMAPs were recorded in the deltoid and biceps. Measurements of CMAPs included negative-peak amplitude from the baseline to peak. The percentage amplitude of CMAPs was calculated in contrast to the opposite side.
  
  
  RESULTS
  Sagittal T2-weighted MRI showed spinal cord compression in all patients from Group 1 and in four patients from Group 2. Deltoid muscle CMAPs: Three patients from Group 1 and all eight patients from Group 2 had a CMAPs' amplitude on the normal side that was greater than 10 mV. Biceps brachii muscle CMAPs: four patients from Group 1 and four patients from Group 2 had a CMAPs' amplitude on the normal side that was greater than 10 mV.
  
  
  CONCLUSIONS
  Patients with a CMAPs amplitude on the normal side that exceeded 10 mV had no impingement of the AH. A CMAPs' amplitude that exceeded 10 mV on the normal side and a CMAPs' amplitude of more than 50% on the affected side compared with the normal side indicated slight involvement of VNR. These patients were able to fully recover function.
authors.affiliation: Department of Orthopaedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan. i-yasuak@yamaguchi-u.ac.jp
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Imajo
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Kato
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Kanchiku
authors.forename: Hidenori
authors.initials: H
authors.lastname: Suzuki
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Taguchi
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D000368:Aged; D057645:Deltoid Muscle / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D011379:Prognosis; D014897:Spinal Muscular Atrophies of Childhood / Q000175:diagnosis* / Q000473:pathology*; D013126:Spinal Nerve Roots / Q000502:physiology*; D055009:Spondylosis / Q000175:diagnosis* / Q000473:pathology*