title: Intraoperative spinal cord monitoring of C5 palsy after cervical laminoplasty.
abstract: METHODS
  Retrospective study of C5 palsy after laminoplasty for cervical myelopathy.
  
  
  OBJECTIVE
  The objectives of this study were to investigate the morphologic characteristic of C5 palsy patients undergoing cervical laminoplasty with the intraoperative motor-evoked potential (MEP).
  
  
  BACKGROUND
  A study reported prophylactic foraminotomy for C5 paralysis after laminoplasty for cervical myelopathy. However, no indications have been established. There have been few reports on the intraoperative monitoring of the C5 palsy. This palsy is reported to happen a few days after the surgery in many cases, and the possibility of its detection by intraoperative spinal cord monitoring is unclear.
  
  
  METHODS
  Of 153 patients with cervical myelopathy, 9 showed a decrease in upper muscle strength by 1 grade or more by postoperative manual muscle test. Of the 9 patients, 4 patients underwent segmental monitoring of upper limbs by MEP and were included in the paralysis group. Of the 153 patients, 74 (444 muscles) in whom both preoperative and postoperative manual muscle test of the upper limbs showed grade 5, and in whom the MEP monitoring of all these muscles was performed, were included in the nonparalysis group. We investigated the presence of intraoperative changes in 4 MEP parameters: amplitude, latency, duration, and waveform pattern, and the presence of foraminal stenosis in the cross-sectional view of preoperative myelographic computed tomography.
  
  
  RESULTS
  In the paralysis group (9 muscles) and nonparalysis group (444 muscles), delay in latency was not observed in any muscle (0% and 0%), and 50% or more reduction of amplitude in 1 muscle (11%) and 22 (5%), prolongation of duration in 1 (11%) and 6 (1%), changes of waveform pattern in 3 (33%) and 40 (9%), and foraminal stenosis in 5 (56%) and 80 (18%), respectively.
  
  
  CONCLUSIONS
  In the paralysis group, the incidences of waveform pattern change on intraoperative MEP and stenosis of the intervertebral foramen were higher than those in the nonparalysis group.
authors.affiliation: Department of Orthopaedic Surgery, Nagoya Kyoritsu Hospital, Nagoya, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Yanase
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Matsuyama
authors.forename: Kikuko
authors.initials: K
authors.lastname: Mori
authors.forename: Yuka
authors.initials: Y
authors.lastname: Nakamichi
authors.forename: Takako
authors.initials: T
authors.lastname: Yano
authors.forename: Takahiro
authors.initials: T
authors.lastname: Naruse
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Sakai
authors.forename: Shiro
authors.initials: S
authors.lastname: Imagama
authors.forename: Zenya
authors.initials: Z
authors.lastname: Ito
authors.forename: Yasutsugu
authors.initials: Y
authors.lastname: Yukawa
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Kamiya
authors.forename: Keigo
authors.initials: K
authors.lastname: Ito
authors.forename: Tokumi
authors.initials: T
authors.lastname: Kanemura
authors.forename: Koji
authors.initials: K
authors.lastname: Sato
authors.forename: Hisashi
authors.initials: H
authors.lastname: Iwata
mesh_terms: D002574:Cervical Vertebrae / Q000601:surgery*; D019299:Decompression, Surgical / Q000009:adverse effects*; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006801:Humans; D007796:Laminectomy / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010243:Paralysis / Q000209:etiology*; D020127:Recovery of Function; D012189:Retrospective Studies; D013116:Spinal Cord / Q000503:physiopathology* / Q000601:surgery; D013118:Spinal Cord Diseases / Q000601:surgery*; D050781:Transcranial Magnetic Stimulation