Vasoactive treatment for hearing preservation in acoustic neuroma surgery.
OBJECTIVE
Delayed hearing loss following surgery for acoustic neuroma indicates anatomical and functional preservation of the cochlear nerve and implies that a pathophysiological mechanism is initiated during surgery and continues thereafter. Intraoperative brainstem auditory evoked potentials (BAEPs) typically demonstrate gradual reversible loss of components in these patients.


METHODS
Based on this BAEP pattern, a consecutive series of 41 patients with unilateral acoustic neuromas was recruited into a prospective randomized study to investigate hearing outcomes following the natural postoperative course and recuperation after vasoactive medication. Both groups were comparable in patient age, tumor size, and preoperative hearing level. Twenty patients did not receive postoperative medical treatment. In 70% of these patients anacusis was documented and in 30% hearing was preserved. Twenty-one patients were treated with hydroxyethyl starch and nimodipine for an average of 9 days. In 66.6% of these patients hearing was preserved and in 33.3% anacusis occurred.


CONCLUSIONS
These results are statistically significant (p < 0.05, chi2 = 5.51) and provide evidence that these surgically treated patients suffer from a disturbed microcirculation that causes delayed hearing loss following removal of acoustic neuromas.
Strauss
C
C
Department of Neurosurgery, University of Erlangen-Nuremberg, Erlangen, Germany. christian.strauss@neurochir.med.uni-erlangen.de
Bischoff
B
B
Neu
M
M
Berg
M
M
Fahlbusch
R
R
Romstöck
J
J
D000328:Adult; D000368:Aged; D003638:Deafness / Q000209:etiology; D016057:Evoked Potentials, Auditory, Brain Stem; D006309:Hearing; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000627:therapeutic use*; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000188:drug therapy* / Q000503:physiopathology / Q000601:surgery*; D009553:Nimodipine / Q000627:therapeutic use*; D010952:Plasma Substitutes / Q000627:therapeutic use*; D011182:Postoperative Care; D011183:Postoperative Complications; D011184:Postoperative Period; D011446:Prospective Studies; D016896:Treatment Outcome; D014665:Vasodilator Agents / Q000627:therapeutic use*
D006895:Hydroxyethyl Starch Derivatives; D010952:Plasma Substitutes; D014665:Vasodilator Agents; D009553:Nimodipine