Preoperative Tinnitus Research Articles

Effect of tumor removal on tinnitus in patients with vestibular schwannoma

Tinnitus is one of the most common symptoms in patients with vestibular schwannomas (VSs), but the effect of surgery on this symptom has not been fully evaluated. The aim of this study was to define the effect on tinnitus of tumor removal, cochlear nerve resection, and useful hearing preservation in patients with VSs. The authors retrospectively analyzed the status of tinnitus before and after surgery in 242 patients with unilateral VSs who underwent surgery via the retrosigmoid lateral suboccipital approach. Of 242 patients, 171 (70.7%) complained of tinnitus before surgery; the symptom disappeared in 25.2%, improved in 33.3%, remained unchanged in 31.6%, and worsened in 9.9% of these cases after tumor removal. In the 171 patients with preoperative tinnitus, the cochlear nerve was resected in 85 (49.7%) and preserved in 86 (50.3%), but there was no significant difference in the incidence of postoperative tinnitus between these 2 groups (p = 0.293). In the 71 patients without preoperative tinnitus, the symptom developed postoperatively in 6 cases (8.5%). Among those without preoperative tinnitus, the cochlear nerve was resected in 45 cases (63.4%) and tinnitus appeared postoperatively in 3 (6.7%). The authors also analyzed the association between postoperative tinnitus and useful hearing preservation, but could not find any statistically significant association between the 2 factors (p = 0.153). Tumor removal via the retrosigmoid lateral suboccipital approach may provide some chance for improvement of tinnitus in patients with VSs; however, neither cochlear nerve resection nor useful hearing preservation affects the postoperative development of tinnitus.

Clinical predictors of facial nerve outcome after translabyrinthine resection of acoustic neuromas

The translabyrinthine approach to acoustic neuroma resection offers excellent exposure for facial nerve dissection with 95% preservation of anatomic continuity. Acceptable outcome in facial asymptomatic patients is reported at 64-90%, but transient postoperative deterioration often occurs. The objective of this study was to identify preoperative clinical presentation and intraoperative surgical findings that predispose patients to facial nerve dysfunction after acoustic neuroma surgery. The charts of 128 consecutive translabyrinthine patients were examined retrospectively to identify new clinical and intraoperative predictors of facial nerve outcome. Postoperative evaluation of patients to normal function or mild asymmetry upon close inspection (House-Brackmann grades of I or II) was defined as an acceptable outcome, with obvious asymmetry to no movement (grades III to VI) defined as unacceptable. Intraoperative nerve stimulation was performed in all cases, and clinical grading was performed by a single neurosurgeon in all cases. Among patients with no preoperative facial nerve deficit, 87% had an acceptable result. Small size (P < 0.01) and low intraoperative nerve stimulation of < 0.10 mA (P< 0.01) were reaffirmed as predictive of functional nerve preservation. Additionally, preoperative tinnitus (P = 0.03), short duration of hearing loss (P< 0. 01), and lack of subjective tumour adherence to the facial nerve (P = 0.02) were independently correlated with positive outcome. Our experience with the translabyrinthine approach reveals the previously unestablished associations of facial nerve outcome to include presence of tinnitus and duration of hypoacusis. Independent predictors of tumour size and nerve stimulation thresholds were reaffirmed, and the subjective description of tumour adherence to the facial nerve making dissection more difficult appears to be important.

Changes in psychophysical parameters during the first month of programming the Nucleus Contour and Contour Advance cochlear implants

This retrospective study evaluated the psychophysical parameters of 29 postlingually deafened adults who had received a Nucleus Contour or Contour Advance implant during the first month of fitting in order to determine how many sessions were required to obtain a stable implant MAP. The T-levels did not differ significantly across the five fitting sessions, but the C-levels as well as the dynamic range showed an increase up to the fourth session. For all psychophysical parameters the basal, medial and apical portion of the electrode array differed significantly across sessions. Subjects with a Nucleus Contour implant had higher comfortable levels than subjects with a Contour Advance implant. The duration of deafness, presence of preoperative tinnitus, aetiology, frequency of fitting, stimulus rate and number of active channels did not significantly influence the psychophysical levels. These results suggested that four fitting sessions within the first three weeks after switch on should initially suffice and the fifth session could be planned beyond one month. Copyright © 2006 John Wiley & Sons, Ltd.

The Prevalence and Onset of Gaze Modulation of Tinnitus and Increased Sensitivity to Noise After Translabyrinthine Vestibular Schwannoma Excision

To determine the prevalence and timing of onset of gaze-modulated tinnitus and increased sensitivity to noise in patients who had undergone translabyrinthine excision of a vestibular schwannoma. Retrospective questionnaire study. University hospital departments of audiology and neurotology. A cohort of 359 patients who had undergone translabyrinthine excision of a vestibular schwannoma in the period 1997 to 2003. Translabyrinthine excision of a unilateral sporadic vestibular schwannoma. Patient reports and visual analogue scale measures of the timing of onset of gaze-modulated tinnitus and the presence, timing of onset, and persistence of increased sensitivity to noise after surgery. Completed questionnaires were returned by 275 patients (77%), of whom 132 (48%) were men and 143 (52%) were women. Preoperative tinnitus was reported in 150 patients (55%). In 124 of these 150 (83%) the tinnitus persisted, and in 26 of 150 (17%) it abated. Of the 125 patients without preoperative tinnitus, 43 (34%) developed it postoperatively. In 167 (61%) patients of the total group of 275, postoperative tinnitus was reported. Gaze-modulated tinnitus was reported in 53 patients (19%). Somatic-evoked or -modulated tinnitus was reported in 38 patients (14%). In response to the question, "Did you notice being extra sensitive to noise after your operation?," 138 patients (50%) replied that they did. In 111 patients, this persisted. The onset of the modulation of tinnitus was distributed throughout the postoperative period, whereas the onset of increased sensitivity to noise was overwhelmingly in the first 2 months after surgery. Gaze modulation of tinnitus after vestibular schwannoma removal was identified in 19% of patients in this series. The onset data did not convincingly argue for any specific mechanism. The prevalence of increased sensitivity to noise is surprising and may represent central hyperacusis in response to unilateral deafferentation of the auditory system.

Changes in psychophysical parameters during the first month of programming the Nucleus Contour and Contour Advance cochlear implants

This retrospective study evaluated the psychophysical parameters of 29 postlingually deafened adults who had received a Nucleus Contour or Contour Advance implant during the first month of fitting in order to determine how many sessions were required to obtain a stable implant MAP. The T-levels did not differ significantly across the five fitting sessions, but the C-levels as well as the dynamic range showed an increase up to the fourth session. For all psychophysical parameters the basal, medial and apical portion of the electrode array differed significantly across sessions. Subjects with a Nucleus Contour implant had higher comfortable levels than subjects with a Contour Advance implant. The duration of deafness, presence of preoperative tinnitus, aetiology, frequency of fitting, stimulus rate and number of active channels did not significantly influence the psychophysical levels. These results suggested that four fitting sessions within the first three weeks after switch on should initially suffice and the fifth session could be planned beyond one month.

Long-term hearing results after stapes surgery: a 20-year follow-up.

The aim of this study was to evaluate the results of stapes surgery after 20 years of follow-up and to compare the results between large fenestra versus small fenestra stapedotomy. Retrospective clinical study. Tertiary referral center (university hospital). One hundred forty-two patients with otosclerosis treated by surgery. Eighty patients had a total stapedectomy with House-wire prosthesis and 62 patients a stapedotomy with Teflon-piston prosthesis. Preoperative, postoperative, and long-term hearing thresholds were compared. Patients filled in a questionnaire about the impact of surgery on the quality of life and postoperative symptoms. The long-term pure tone average improvement did not differ significantly between the techniques compared with the preoperative values. The air-bone gap tended to enlarge as a function of time. The change in the pure tone average was 0.9 dB per year for both techniques. In the questionnaire, some patients reported vertigo, tinnitus, loud noise intolerance, and taste disturbances. Loud noise intolerance seemed to persist in the long term. Surgery had no effect on preoperative tinnitus. There were no statistically significant differences between the techniques regarding hearing results. Over the long term, both techniques are safe and effective in restoring hearing and improving quality of life.

Treatment of acoustic neuroma: stereotactic radiosurgery vs. microsurgery

Purpose: Two major treatment options are available for patients with acoustic neuroma, microsurgery and radiosurgery. Our objective was to compare these two treatment modalities with respect to tumor growth control, hearing preservation, development of cranial neuropathies, complications, functional outcome, and patient satisfaction.Methods and Materials: To compare radiosurgery with microsurgery, we analyzed 96 patients with unilateral acoustic neuromas treated with Leksell Gamma Knife or microsurgery at Memorial Hermann Hospital, Houston, Texas, between 1993 and 2000. Radiosurgery technique involved multiple isocenter (1–30 single fraction fixed-frame magnetic resonance imaging) image-based treatment with a mean dose prescription of 14.5 Gy. Microsurgery included translabyrinthine, suboccipital, and middle fossa approaches with intraoperative neurophysiologic monitoring. Preoperative patient characteristics were similar except for tumor size and age. Patients undergoing microsurgery were younger with larger tumors compared to the radiosurgical group. The tumors were divided into small <2.0 cm, medium 2.0–3.9 cm, or large >4.0 cm. Median follow-up of the radiosurgical group was longer than the microsurgical group, 48 months (3–84 months) vs. 24 months (3–72 months).Results: There was no statistical significance in tumor growth control between the two groups, 100% in the microsurgery group vs. 91% in the radiosurgery group (p > 0.05). Radiosurgery was more effective than microsurgery in measurable hearing preservation, 57.5% vs. 14.4% (p = 0.01). There was no difference in serviceable hearing preservation between the two groups. Microsurgery was associated with a greater rate of facial and trigeminal neuropathy in the immediate postoperative period and at long-term follow-up. The rate of development of facial neuropathy was significantly higher in the microsurgical group than in the radiosurgical group (35% vs. 0%, p < 0.01 in the immediate postsurgical period and 35.3% vs. 6.1%, p = 0.008, at long-term follow-up). Similarly, the rate of trigeminal neuropathy was significantly higher in the microsurgical group than in the radiosurgical group (17% vs. 0% in the immediate postoperative period, p < 001, and 22% vs. 12.2%, p = 0.009, at long-term follow-up). There was no significant difference in exacerbation of preoperative tinnitus, imbalance, dysarthria, dysphagia, and headache. Patients treated with microsurgery had a longer hospital stay (2–16 days vs. 1–2 days, p < 0.01) and more perioperative complications (47.8% vs. 4.6%, p < 0.01) than did patients treated with radiosurgery. There was no correlation between the microsurgical approach used and postoperative symptoms. There was no difference in the postoperative functioning level, employment, and overall patient satisfaction. There was no correlation between the radiation dose, tumor size, number of isocenters used, and postoperative symptoms in the radiosurgical group.Conclusion: Radiosurgical treatment for acoustic neuroma is an alternative to microsurgery. It is associated with a lower rate of immediate and long-term development of facial and trigeminal neuropathy, postoperative complications, and hospital stay. Radiosurgery yields better measurable hearing preservation than microsurgery and equivalent serviceable hearing preservation rate and tumor growth control.

Gaze-evoked tinnitus following acoustic neuroma resection: a de-afferentation plasticity phenomenon?

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.

Tinnitus and Vestibular Schwannoma Surgery

The aim of this study was to evaluate the effect of operation on tinnitus in vestibular schwannoma (VS) patients. Altogether, 251 VS patients who underwent surgery during the years 1979 to 1993 at Helsinki University Central Hospital were included in the study. Information on preoperative tinnitus was collected from previously acquired data and postoperative tinnitus was evaluated. Preoperatively, 62.6% of the patients had experienced tinnitus. Of those with preoperative tinnitus, 47.4% also had it postoperatively, but of those 93 patients without preoperative tinnitus, 39.8% had tinnitus postoperatively. Tinnitus is one of the primary symptoms of VS, together with hearing impairment and disequilibrium. The risk of postoperative tinnitus is almost 40%, and with preoperative tinnitus, the risk is 7.6% higher. In the majority tinnitus was not related to the surgery. Only a few patients had severe problems with tinnitus; difficulty understanding speech was the major complaint.

Dose reduction improves hearing preservation rates after intracanalicular acoustic tumor radiosurgery.

To assess the potential for long-term serviceable hearing preservation in intracanalicular acoustic tumor patients who underwent stereotactic radiosurgery. Between August 1987 and December 1997, 29 patients with intracanalicular acoustic tumors underwent stereotactic radiosurgery at our center using the Leksell gamma knife (Elekta Instruments, Inc., Atlanta, GA). Fifteen assessable patients had serviceable preradiosurgery hearing (pure tone average, < or = 50 dB; speech discrimination score, > or = 50%). We retrospectively analyzed our hearing results and compared hearing preservation in patients who received a minimal tumor dose of 14 Gy or less versus those who received more than 14 Gy to the tumor margin. No perioperative patient morbidity or mortality was observed. Serviceable hearing was preserved in 11 (73%) of 15 assessable patients (actuarial rate, 65%). Long-term follow-up demonstrated serviceable hearing preservation in 10 (100%) of 10 patients who received marginal tumor doses of 14 Gy or less but in only one of five patients who received more than 14 Gy. Preradiosurgery Gardner-Robertson class was preserved in 49%, and testable hearing was present in 68% of patients who had any testable hearing at presentation. Five patients demonstrated improvement in hearing (three had serviceable and two had nonserviceable hearing before radiosurgery). No patient developed a facial or trigeminal neuropathy. Seven of 13 patients with preoperative tinnitus continued to experience tinnitus in follow-up. Episodic vertigo continued in 3 of the 11 patients who presented with vertigo. Gamma knife radiosurgery (using conformal dose planning, small-beam geometry, and < or = 14 Gy to the margin) prevents tumor growth and achieves excellent hearing preservation rates.

Does Hearing Preservation Surgery for Acoustic Neuromas Affect Tinnitus?

Questionnaires returned from 202 patients who had undergone acoustic neuroma resection were analyzed with special reference to the effect on tinnitus of surgery that attempted to preserve hearing versus surgery that did not. We also examined the relationship between postoperative hearing and tinnitus following surgery to preserve hearing (103 patients, HP group). The incidence of preoperative tinnitus in the HP group was 78.6%; postoperatively it increased to 89.3% (p = 0.0367). The remaining 99 patients (non-HP) underwent labyrinthectomy during tumor resection. In this group tinnitus occurred in 72.7% preoperatively and in 67.3% postoperatively (p = 0.4097). Our findings show that when tinnitus was absent preoperatively, 85% of the HP group developed it postoperatively compared to 31% of patients in the non-HP group. The outcome of surgery to preserve hearing had no bearing on the loudness or annoyance of postoperative tinnitus. Although postoperative tinnitus is tolerable to most patients, they must be informed prior to surgery about its possible occurrence or worsening, especially if the goal is to preserve hearing.

Tinnitus and translabyrinthine acoustic neuroma surgery.

The purpose of this investigation was to study the effects of translabyrinthine acoustic neuroma surgery on tinnitus in a consecutive sample of patients operated on between 1988 and 1994 in Uppsala (Sweden). A postal questionnaire was returned by 141 patients, yielding a 90% response rate without reminder. The results showed that tinnitus was experienced by 70% of the patients before surgery and 60% after surgery. In general, low degrees of tinnitus distress were found, which was confirmed by the questionnaire results. Ratings of tinnitus distress after surgery, using the Klockhoff and Lindblom grading system, showed that 48% had tinnitus of grade I, 46% of grade II, and 6% of grade III. Pre- and postsurgery grading of distress did not change significantly. There was a 35% risk for developing tinnitus when no preoperative tinnitus was present and a 15% chance that tinnitus disappears when present preoperatively.

Translabyrinthine vestibular schwannoma surgery: postoperative tinnitus and cochlear nerve integrity

Cochlear neurectomy as a surgical treatment for tinnitus is known to be only partially successful in many conditions. Translabyrinthine surgery for acoustic neuromas may be performed using a dissection technique which preserves an ‘anterior curtain’ which helps to protect the facial nerve. The cochlear nerve may be retained within this tissue though it can be cut during the dissection. To assess whether its integrity affects tinnitus the video recordings of 117 patients undergoing this operation were reviewed to grade the likelihood of the cochlear nerve having been retained intact. A postal questionnaire, with a response rate of 83%, was used to assess tinnitus. Patients who had a probable or definite nerve section had significantly lower postoperative tinnitus severity. The same relationship was found when patients were matched for tumour size and preoperative tinnitus. This procedure could act as a model for the effect of cochlear neurectomy on tinnitus associated with acoustic neuromas in a prospective trial.

Fenestration and occlusion of posterior semicircular canal for patients with intractable benign paroxysmal positional vertigo.

A series of 15 patients with intractable benign paroxysmal positional vertigo (BPPV) who had fenestration and occlusion of the posterior semicircular canal (FOP) surgery commencing in December 1990 are reported. Follow-up was from 14 to 40 months. All patients reported a cure of their positional vertigo. No patient regretted having the surgery. All patients had a negative Dix-Hallpike test post-operatively and the test remained negative for the duration of follow-up. Eight patients had a mild high frequency sensorineural hearing (SNHL) loss post-operatively which had almost recovered six months later. No patient reported any change in their hearing following surgery. Of the 10 patients who did not have pre-operative tinnitus, six developed tinnitus but it was not considered significant by them. All patients developed mild unsteadiness following surgery which gradually improved with mobilization and physiotherapy if necessary. The operation preserves hearing, is technically straightforward, well-tolerated and effective.

Vestibular nerve section

Introduction: Vestibular nerve section is considered to be the most effective surgical procedure for control of intractable symptoms secondary to labyrinthine and eighth nerve function. This study was developed to retrospectively evaluate the efficacy of vestibular nerve section in patients treated for disabling labyrinthine dysfunction. Methods: A retrospective review of hospital and office records was carried out on 39 patients who underwent vestibular nerve section. All patients received a comprehensive questionnaire to subjectively evaluate efficacy. Results: Questionnaires were returned from 36 of 39 patients. Follow-up averaged 51 months. A decrease in vertiginous attacks was reported by 94% of patients. An improvement in activity tolerance was reported by 30% of patients. Preoperative tinnitus and ear fullness reportedly improved after surgery in 53% and 65% or patients respectively. Complications encountered included cerebrospinal fluid (CSF) leak (six patients), meningitis (two patients), and intracranial fluid collection (one patient). Conclusion: Vestibular nerve section is a relatively safe and effective method of treatment for intractable vertigo.

Tinnitus suppression following cochlear implantation. A multifactorial investigation.

The effects of cochlear implant on loudness, annoyance, daily duration, location, and residual inhibition of tinnitus were evaluated by a closed-ended, quantifiable questionnaire in 33 postlingually deafened patients who had received implants at the University of Michigan, Ann Arbor, between 1986 and 1990. Preoperative tinnitus was present in 85% of patients. A statistical comparison of preoperative vs postoperative loudness and annoyance indicated a significant reduction in both of these complaints postoperatively. Loudness and annoyance were significantly correlated, both preoperatively and postoperatively. Fifteen patients (54%) with preoperative tinnitus demonstrated a loudness decrease of 30% or more; 43% demonstrated an annoyance decrease of 30% or more; and 48% demonstrated a decrease of 30% or more in daily tinnitus duration. Patients who experienced a loudness or annoyance decrease of 30% or more after implantation demonstrated significantly higher preoperative levels of these complaints, suggesting that degree of tinnitus reduction after implantation may be related to preoperative loudness and annoyance levels. Contralateral tinnitus suppression was reported by 42% of patients. Residual inhibition ranging from 60 seconds to several hours was reported by 50% of patients, predominantly in the ear with the implant. Age, gender, cause of hearing loss, duration of tinnitus, cochlear implant usage, and time after implantation were not predictive of tinnitus suppression. Overall, the majority of the patients (74%) thought that their cochlear implant was helpful in tinnitus suppression, especially in the ear with the implant. Contralateral residual inhibition and tinnitus suppression suggest a central mechanism contributing to these phenomena.

Late course of preserved hearing and tinnitus after acoustic neurilemoma surgery.

The late course of preserved hearing and tinnitus following retrosigmoid transmeatal surgery for acoustic neurilemoma is reported. Over a period of 5 years, useful hearing was preserved in 15 patients after preservation was attempted in 42 patients. In five patients the hearing was better than the preoperative level; in three it was worse. Three patients developed delayed worsening and fluctuations of hearing in the surgically treated ear during a median follow-up period of 2 1/2 years. While the exact reason for such worsening was not clear in two patients, in one patient it appeared that the muscle graft placed in the internal auditory canal after tumor resection resulted in fibrosis and compromise of the cochlear nerve. The causes of delayed worsening of hearing in the absence of tumor recurrence are analyzed, and possible treatment and methods of prevention of worsening are suggested. In six patients, tinnitus persisted after surgery in the ear with successful preservation of hearing, but hearing was not worsened and the tinnitus was not bothersome to the patient. In one patient with preoperative tinnitus, hearing was not preserved and tinnitus persisted sufficiently to necessitate reexploration and cochlear nerve section.

人工内耳の耳鳴抑制効果

There have been several reports that transcutaneous and transtympanic electrical stimulation and electrical stimulation applied to the promontory can suppress tinnitus. Other papers have assessed of tinnitus reduction in patients with cochlear implants. We investigated preoperative tinnitus in cochlear implant candidates and evaluated the effects on tinnitus of promontory stimulation and of cochlear implantation.Tinnitus was experienced in 90% of cochlear implant candidates. Patients with severely impaired hearing had especially marked tinnitus. Promontory stimulation abolished tinnitus in 22% and reduced it in 50% of patients. The corresponding figures after cochlear implantation were 44% and 39%. The effect continued for several hours after stimulation by the speech processor had been switched off.