title: Postoperative segmental C5 palsy after cervical laminoplasty may occur without intraoperative nerve injury: a prospective study with transcranial electric motor-evoked potentials.
abstract: METHODS
  Intraoperative neurophysiologic monitoring with transcranial electric motor-evoked potentials was performed on patients who underwent cervical laminoplasty at a university hospital in a prospective study.
  
  
  OBJECTIVE
  To evaluate the usefulness of intraoperative spinal cord monitoring with transcranial electric motor-evoked potentials for prediction of the occurrence of segmental motor paralysis after cervical laminoplasty.
  
  
  BACKGROUND
  Segmental motor paralysis occasionally occurs among patients who undergo expansive laminoplasty for cervical myelopathy, and it has been attributed to nerve root lesions caused by either a traumatic surgical technique or a tethering effect after decompression.
  
  
  METHODS
  Sixty-two consecutive patients (47 men and 15 women; mean age 64 years [range 32-89]) who were scheduled to undergo cervical laminoplasty under intraoperative spinal cord monitoring with transcranial electric motor-evoked potentials were included in this study. Transcranial electrical stimulations were delivered through pin-type electrodes, and the evoked potentials were recorded over the deltoid, biceps, and triceps muscles in the bilateral upper extremities and thoracic spinal cord.
  
  
  RESULTS
  Intraoperative evoked potentials were successfully recorded in all muscles in 57 patients (92%), and incomplete evoked potentials were recorded in the remaining 5 patients. No critical decrease in the amplitude of the evoked potentials was observed in any of the 62 patients. All patients showed sufficient postoperative recovery from their clinical symptoms; however, postoperative transient C5 palsy occurred in 3 patients.
  
  
  CONCLUSIONS
  No abnormalities were observed on transcranial electric motor-evoked potential monitoring, even in those patients who developed postoperative transient C5 palsy. These results suggest that the development of postoperative C5 palsy after cervical laminoplasty is not associated with intraoperative injury of the nerve root or the spinal cord, although the precise mechanism of its development is still unclear. Surgeons should be aware that C5 palsy is a possible complication of cervical laminoplasty, even in the absence of intraoperative nerve injury.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan. nobut@hiroshima-u.ac.jp
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Tanaka
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Nakanishi
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Fujiwara
authors.forename: Naosuke
authors.initials: N
authors.lastname: Kamei
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Ochi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002574:Cervical Vertebrae; D003943:Diagnostic Techniques, Neurological; D019054:Evoked Potentials, Motor; D005260:Female; D006785:Hospitals, University; D006801:Humans; D007431:Intraoperative Complications; D007796:Laminectomy / Q000009:adverse effects* / Q000379:methods; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D010243:Paralysis / Q000175:diagnosis / Q000209:etiology*; D011183:Postoperative Complications; D011446:Prospective Studies; D013118:Spinal Cord Diseases / Q000601:surgery*; D020196:Trauma, Nervous System / Q000175:diagnosis / Q000209:etiology*