title: Feasibility of intraoperative motor-evoked potential monitoring for skull base tumors with a high risk of postoperative motor deterioration.
abstract: OBJECTIVE
  To establish the validity and utility of motor-evoked potential (MEPs) monitoring for skull base tumor resection, we explored the relationship between MEP monitoring results and postoperative motor function.
  
  
  METHODS
  MEPs were successfully monitored during 76 operations in 68 patients with a high risk of motor morbidity. MEP monitoring data were correlated with perioperative clinical motor function.
  
  
  RESULTS
  MEPs remained stable in 56 operations (73.7%), and no postoperative motor deterioration was observed. Transient or permanent deterioration of MEPs (<50% of the initial amplitude before surgery) occurred in 20 operations (26.3%). This deterioration was reversible after intervention in seven cases (9.2%). Irreversible deterioration in MEPs was seen in 13 cases (17.1%). In five cases, the final amplitude was greater than 10%. Two of these patients experienced transient loss of MEPs and moderate to severe hemiparesis. Both patients showed full recovery within 6 months after the operation. The other three patients experienced no postoperative worsening of motor function. The final MEP amplitude was less than 10% in the other eight patients, including five with permanent MEP loss. All of these patients experienced severe postoperative motor dysfunction. Recovery of motor function was worse in most participants in this group compared with those in the other groups.
  
  
  CONCLUSIONS
  Intraoperative MEP monitoring is a valid indicator of pyramidal tract pathway function for skull base tumor surgery.
authors.affiliation: Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan. khash@med.kyushu-u.ac.jp
authors.forename: Kimiaki
authors.initials: K
authors.lastname: Hashiguchi
authors.forename: Takato
authors.initials: T
authors.lastname: Morioka
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Yoshida
authors.forename: Koji
authors.initials: K
authors.lastname: Yoshimoto
authors.forename: Tadahisa
authors.initials: T
authors.lastname: Shono
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Natori
authors.forename: Shinji
authors.initials: S
authors.lastname: Nagata
authors.forename: Tomio
authors.initials: T
authors.lastname: Sasaki
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D038524:Diffusion Magnetic Resonance Imaging; D004576:Electromyography / Q000379:methods*; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D009460:Neurologic Examination; D010291:Paresis / Q000503:physiopathology / Q000517:prevention & control; D011183:Postoperative Complications / Q000503:physiopathology* / Q000517:prevention & control*; D011712:Pyramidal Tracts / Q000293:injuries / Q000503:physiopathology; D012307:Risk Factors; D019292:Skull Base Neoplasms / Q000601:surgery*; D014057:Tomography, X-Ray Computed; D055815:Young Adult