title: Intraoperative monitoring of cochlear nerve compound action potential in cerebellopontine angle tumour removal.
abstract: Cochlear nerve compound action potential (CNAP) provides a real-time auditory evoked potential. Because of technical difficulty, CNAP monitoring has not been popular during the removal of cerebellopontine angle (CPA) tumour. To clarify the efficiency of intraoperative CNAP monitoring, we designed an intracranial electrode for CNAP monitoring and performed the simultaneous monitoring of CNAP and auditory brainstem response (ABR) in 10 patients undergoing CPA tumour removal in an attempt to preserve hearing. ABR recordings during microsurgical tumour removal were unsatisfactory in 6 patients because of severe artifacts. Reliable CNAP recordings were obtained without artifacts in all 10 patients throughout surgery. Eight patients preserved useful hearing after tumour removal, and the CNAP amplitude reflected the postoperative hearing. The newly designed intracranial electrode enables CNAP monitoring predicting the postoperative hearing more reliably than ABR. CNAP monitoring is efficient to improve the hearing preservation rate following CPA tumour removal.
authors.affiliation: Department of Neurosurgery, Chiba University School of Medicine, Chiba, Japan. yamakami@med.m.chiba-u.ac.jp
authors.forename: Iwao
authors.initials: I
authors.lastname: Yamakami
authors.forename: Nobuo
authors.initials: N
authors.lastname: Oka
authors.forename: Akira
authors.initials: A
authors.lastname: Yamaura
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000328:Adult; D000368:Aged; D016477:Artifacts; D020295:Brain Stem Neoplasms / Q000503:physiopathology / Q000601:surgery*; D002294:Carcinoma, Squamous Cell / Q000503:physiopathology / Q000601:surgery*; D002528:Cerebellar Neoplasms / Q000503:physiopathology / Q000601:surgery*; D002530:Cerebellopontine Angle / Q000473:pathology*; D003056:Cochlear Nerve / Q000503:physiopathology*; D004867:Equipment Design; D005072:Evoked Potentials, Auditory / Q000502:physiology; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005260:Female; D006801:Humans; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D009464:Neuroma, Acoustic / Q000503:physiopathology / Q000601:surgery*; D011184:Postoperative Period; D055815:Young Adult