title: Combined monitoring of evoked potentials during microsurgery for lesions adjacent to the brainstem and intracranial aneurysms.
abstract: BACKGROUND
  Neurophysiologic monitoring during surgery is to prevent permanent neurological injury resulting from surgical manipulation. To improve the accuracy and sensitivity of intraoperative neuromonitoring, combined monitoring of transcranial electrical stimulation motor evoked potentials (TES-MEPs), somatosensory evoked potentials (SSEPs) and brainstem auditory evoked potentials (BAEPs) was attempted in microsurgery for lesions adjacent to the brainstem and intracranial aneurysms.
  
  
  METHODS
  Monitoring of combined TES-MEPs with SSEPs was attempted in 68 consecutive patients with lesions adjacent to the brainstem as well as intracranial aneurysms. Among them, 31 patients (31 operations, 28 of posterior cranial fossa tumors, 3 of posterior circulation aneurysms) were also subjected to monitoring of BAEPs. The correlation of monitoring results and clinical outcome was studied prospectively.
  
  
  RESULTS
  Combined monitoring of evoked potentials (EPs) was done in 64 (94.1%) of the 68 patients. MEPs monitoring was impossible for 4 patients (5.9%). No complication was observed during the combined monitoring in all the patients. In 45 (66.2%) of the 68 patients, EPs were stable, and they were neurologically intact. Motor dysfunction was detected by MEPs in 8 patients, SSEPs in 5, and BAEPs in 4, respectively.
  
  
  CONCLUSIONS
  A close relationship exists between postoperative motor function and the results of TES-MEPs monitoring. TES-MEPs are superior to SSEPs and BAEPs in detecting motor dysfunction, but combined EPs serve as a safe, effective and invasive method for intraoperative monitoring of the function of the motor nervous system. Monitoring of combined EPs during microsurgery for lesions adjacent to the brainstem and intracranial aneurysms may detect potentially hazardous maneuvers and improve the safety of subsequent procedures.
authors.affiliation: Department of Neurosurgery, First Affiliated Hospital of Fujian Medical University, Fuzhou, China. kdz99988@sina.com
authors.forename: De-Zhi
authors.initials: DZ
authors.lastname: Kang
authors.forename: Zan-Yi
authors.initials: ZY
authors.lastname: Wu
authors.forename: Qing
authors.initials: Q
authors.lastname: Lan
authors.forename: Liang-Hong
authors.initials: LH
authors.lastname: Yu
authors.forename: Zhang-Ya
authors.initials: ZY
authors.lastname: Lin
authors.forename: Chen-Yang
authors.initials: CY
authors.lastname: Wang
authors.forename: Yuan-Xiang
authors.initials: YX
authors.lastname: Lin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001933:Brain Stem / Q000503:physiopathology; D016057:Evoked Potentials, Auditory, Brain Stem; D019054:Evoked Potentials, Motor; D005073:Evoked Potentials, Somatosensory; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008866:Microsurgery; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D012680:Sensitivity and Specificity