Progressive Deterioration of Auditory Evoked Potentials after Excision of an Acoustic Neurinoma: Case Report

Neurosurgery ◽  
1991 ◽  
Vol 28 (4) ◽  
pp. 566-570 ◽  
Author(s):  
Tetsuji Sekiya ◽  
Takashi Iwabuchi ◽  
Masahiro Takiguchi ◽  
Hiroaki Ichijo ◽  
Hitoshi Sasaki
Keyword(s):  
Case Report ◽  
Evoked Potentials ◽  
Cerebellopontine Angle ◽  
Auditory Evoked Potentials ◽  
Nerve Fibers ◽  
Cochlear Nerve ◽  
Acoustic Neurinoma ◽  
Progressive Deterioration

Abstract The authors report the case of a 17-year-old girl who underwent excision of bilateral neurinomas of the cerebellopontine angle. Although her auditory evoked potentials were well maintained during the operation, they deteriorated gradually and progressively for the following 2 months. This seemed to reflect degeneration of the cochlear nerve fibers initiated by operative manipulation in the cerebellopontine angle in a patient who had no hearing when she awoke from surgery.

Deterioration of auditory evoked potentials during cerebellopontine angle manipulations

1985 ◽  
Vol 63 (4) ◽  
pp. 598-607 ◽  
Author(s):  
Tetsuji Sekiya ◽  
Takashi Iwabuchi ◽  
Shigeki Kamata ◽  
Takashi Ishida
Keyword(s):  
Evoked Potentials ◽  
Brain Stem ◽  
Real Time ◽  
Action Potentials ◽  
Cerebellopontine Angle ◽  
Auditory Evoked Potentials ◽  
Cochlear Nerve ◽  
Cerebellar Hemisphere ◽  
Common Finding ◽  
Interpeak Latency

✓ Evoked action potentials from the internal auditory meatus portion of the cochlear nerve (IAM-EAP's) and brain-stem auditory evoked potentials (BAEP's) from the vertex were simultaneously recorded during cerebellopontine angle (CPA) manipulations (retractions of the cerebellar hemisphere and the cochlear nerve) in dogs. The BAEP changes noted in these dogs were the same as those seen in patients. The IAM-EAP's showed graded deterioration related to BAEP changes. The results are as follows: 1) Prolongation of the I–V interpeak latency of BAEP's, the most common finding during CPA manipulations, is the reflection of prolongation of the I–II interpeak latency, which is caused by conduction impairment or block of the nerve impulses between the extracranial portion of the cochlear nerve and the brain stem. The operative manipulations representing stretch or compression injury to the cochlear nerve in the CPA leads to an acute traumatic cranial nerve root lesion — a retrocochlear lesion. 2) The obliteration of all BAEP components including wave I cannot be caused by conduction block. This is caused by occlusion of the internal auditory artery. Wave I of the BAEP's and the P1-N1 complex of the IAM-EAP's are important indicators of cochlear blood flow during surgical intervention. 3) As possible causes of internal auditory artery obstruction, mechanical distortion of the relationship between the anterior inferior cerebellar artery (AICA) and the internal auditory artery at the junctional portion, mechanical vasospasm of the AICA-internal auditory artery complex, and ensuing noreflow phenomena are discussed. 4) Evoked action potentials are expected to be a useful intraoperative real-time monitor during CPA surgery that can detect rapid changes derived from cochlear artery insufficency. The real-time aspects can overcome some of the disadvantages of BAEP monitoring.

Preservation of Cochlear Nerve Function with the Aid of Brain Stem Auditory Evoked Potentials

Neurosurgery ◽  
1982 ◽  
Vol 11 (1_pt_1) ◽  
pp. 16-19 ◽  
Author(s):  
Russell W. Hardy ◽  
Sam E. Kinney ◽  
Hans Lueders ◽  
Ronald P. Lesser
Keyword(s):  
Evoked Potentials ◽  
General Anesthesia ◽  
Brain Stem ◽  
Cerebellopontine Angle ◽  
Auditory Evoked Potentials ◽  
Neurological Function ◽  
Cochlear Nerve ◽  
Nerve Function ◽  
Cochlear Function ◽  
Cerebellopontine Angle Tumors

Abstract Somatosensory, visual, and auditory evoked potentials have been used to monitor neurological function in patients under general anesthesia. This paper describes the preservation of useful hearing in three patients with cerebellopontine angle tumors. In each case, cochlear function was monitored during the procedure, and confirmation of intact conduction intraoperatively was associated with preserved hearing postoperatively.

Intraoperative monitoring of brain-stem auditory evoked potentials

1982 ◽  
Vol 57 (5) ◽  
pp. 674-681 ◽  
Author(s):  
Betty L. Grundy ◽  
Peter J. Jannetta ◽  
Phyllis T. Procopio ◽  
Agnes Lina ◽  
J. Robert Boston ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Brain Stem ◽  
Auditory Nerve ◽  
Intraoperative Monitoring ◽  
Cerebellopontine Angle ◽  
Auditory Evoked Potentials ◽  
Irreversible Loss ◽  
Content Type ◽  
Complete Obliteration ◽  
Fine Print

✓ Brain-stem auditory evoked potentials (BAEP) were monitored during 54 neurosurgical operations in the cerebellopontine angle. The BAEP were irreversibly obliterated in five patients who required deliberate section of the auditory nerve. Technical difficulties interfered with monitoring in three cases, and three patients had deafness and absent BAEP preoperatively. Reversible alterations in BAEP were seen during 32 operations, with recovery after as long as 177 minutes of virtually complete obliteration. Changes in BAEP were associated with surgical retraction, operative manipulation, positioning of the head and neck for retromastoid craniectomy, and the combination of hypocarbia and moderate hypotension. In 19 cases, waveforms improved after specific interventions made by the surgeon or anesthesiologist because of deteriorating BAEP. In 13 other cases, BAEP recovered after maneuvers not specifically related to the electrophysiological monitoring, most often completion of operative manipulation. Whenever BAEP returned toward normal by the end of anesthesia, even after transient obliteration, hearing was preserved. Irreversible loss of BAEP occurred only when the auditory nerve was deliberately sacrificed. The authors conclude that monitoring of BAEP may help prevent injury to the auditory nerve and brain stem during operations in the cerebellopontine angle.

Clinical and Neurophysiological Observations after Superior Petrosal Vein Obstruction during Surgery of the Cerebellopontine Angle: Case Report

Neurosurgery ◽  
2001 ◽  
Vol 48 (5) ◽  
pp. 1157-1161 ◽  
Author(s):  
Christian Strauss ◽  
Mandana Neu ◽  
Barbara Bischoff ◽  
Johann Romstöck
Keyword(s):  
Evoked Potentials ◽  
Cerebellopontine Angle ◽  
Auditory Evoked Potentials ◽  
Venous Drainage ◽  
Lateral Approach ◽  
Petrous Apex ◽  
Brainstem Auditory Evoked Potentials ◽  
Petrosal Vein ◽  
Superior Petrosal Vein ◽  
Temporary Clipping

Abstract IMPORTANCE Preservation of venous drainage during surgery of the cerebellopontine angle has received little attention. CLINICAL PRESENTATION We describe changes in brainstem auditory evoked potentials after temporary obstruction of the superior petrosal vein during surgical resection of a small meningioma at the petrous apex via a standard suboccipital-lateral approach. Temporary clipping of the petrosal vein resulted in deterioration of the brainstem auditory evoked potentials. The tumor was removed with preservation of the superior petrosal vein. CONCLUSION A transient postoperative cochlear nerve deficit emphasizes the importance of venous drainage and its preservation during surgery for small lesions of the cerebellopontine angle that do not distort normal anatomic structures.

Cerebellopontine Angle Tumor Causing Contralateral Trigeminal Neuralgia: A Case Report

Neurosurgery ◽  
1987 ◽  
Vol 21 (1) ◽  
pp. 84-86 ◽  
Author(s):  
Robert B. Snow ◽  
Richard A. R. Fraser
Keyword(s):  
Case Report ◽  
Trigeminal Neuralgia ◽  
Cerebellopontine Angle ◽  
Acoustic Neurinoma ◽  
Cerebellopontine Angle Tumor ◽  
Cerebellopontine Angle Tumors

Abstract A case of trigeminal neuralgia caused by a contralateral acoustic neurinoma is reported. The patient's tic pain was completely alleviated after removal of the tumor. Previously reported cases of trigeminal neuralgia caused by contralateral cerebellopontine angle tumors are reviewed, and the pathophysiology of this disorder is discussed. (Neurosurgery 21: 84-86, 1987)

Preservation of cochlear nerve function with the aid of brain stem auditory evoked potentials

Neurosurgery ◽  
1982 ◽  
Vol 11 (1 Pt 1) ◽  
pp. 16???9 ◽  
Author(s):  
R W Hardy ◽  
S E Kinney ◽  
H Lueders ◽  
R P Lesser
Keyword(s):  
Evoked Potentials ◽  
Brain Stem ◽  
Auditory Evoked Potentials ◽  
Cochlear Nerve ◽  
Nerve Function
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