ABSTRACT
A review of the prevalence of gaze-evoked tinnitus in patients who have undergone acoustic neuroma resection was undertaken. The relationship of gaze-evoked tinnitus to tumour size, pre-existing tinnitus, side of the lesion or direction of eye gaze was also analysed. The design was a retrospective review of patients who underwent total unilateral translabyrinthine vestibular schwannoma resection by the senior author. Patients 1 year and 5 years following surgery were assessed. Results were obtained by either direct questioning in a clinical setting or via questionnaire. Data was collected on 36 subjects at an average of 14.6 months postoperatively (range 8-20 months) and on 32 subjects at an average 62 months postoperatively (range 56-68 months). Of the first group, 13 had evidence of gaze-evoked tinnitus (36%) compared with six (19%) of the second. The presence of preoperative tinnitus was a significant variable in univariate and multivariate analyses of the presence of postoperative tinnitus and postoperative gaze-evoked tinnitus. In a reduced model multivariate logistic regression using the two groups combined, the significant independent risk factors for gaze-evoked postoperative tinnitus were female sex (P = 0.046, odds ratio = 4.3), right side surgery (P = 0.02, odds ratio = 5.5) and pre-existing tinnitus (P = 0.008, odds ratio = 24.2). Gaze-evoked tinnitus is more common than previously reported in patients undergoing vestibular schwannoma resection. The underlying pathophysiology remains unclear but neural plasticity following unilateral de-afferentation remains a viable theory. The reduced prevalence over time suggests that this phenomenon may represent an active reinnervation process within the brain, which stabilizes with time. The significance of pre-existing tinnitus suggests that mechanisms of neural reorganization modify an existing physiological pathway. Further research is required into the longevity of this phenomenon, preferably with longitudinal studies.
Subject(s)
Eye Movements , Neuroma, Acoustic/surgery , Neuronal Plasticity , Postoperative Complications , Tinnitus/etiology , Adult , Aged , Auditory Pathways/physiopathology , Female , Humans , Logistic Models , Male , Middle Aged , Multivariate Analysis , Retrospective Studies , Risk Factors , Tinnitus/physiopathologyABSTRACT
The authors present a rare clinical entity in a schwannoma of the chorda tympani. The case is discussed including the difficulty in making the diagnosis and management.
Subject(s)
Chorda Tympani Nerve/pathology , Cranial Nerve Neoplasms/diagnosis , Neurilemmoma/diagnosis , Tomography, X-Ray Computed , Adult , Female , Humans , Magnetic Resonance ImagingABSTRACT
A case of successful cochlear implantation following irradiation of the temporal bone is presented. Loss of cochlear architecture is demonstrated and is attributable to previous radiation. Viability of cochlear nerve and spiral ganglion following radiation is questioned. To date there has been only one previously published report on the subject.
ABSTRACT
A case is presented of solitary fibrous tumor occurring in the cerebello-pontine angle. There have been only two other reported cases of a solitary fibrous tumors in this region. Imaging studies showed the tumor to be characteristic in shape and position of an acoustic tumor. However, at surgery the tumor was found to have a "rock hard" consistency. Solitary fibrous tumor differs from acoustic schwannoma and meningioma in its histopathological features and in this case, regrowth, after incomplete excision, was extremely rapid.
