Hearing preservation in acoustic neuroma surgery.

This article reviews the Montreal experience of hearing preservation in acoustic neuroma surgery. The medical records since 1995 of 36 patients who underwent acoustic neuroma extirpation with the intent to preserve hearing were examined. Intraoperative monitoring was conducted using auditory brainstem response measurement with electrocochleography via a transtympanic electrode. The role of intraoperative monitoring in guiding surgical technique and its correlation with postoperative hearing outcome are discussed. A review of the literature regarding hearing preservation in acoustic neuroma surgery is included.     

Intraoperative corticosteroids in acoustic tumor surgery.

BACKGROUND: Corticosteroids are frequently used for the prevention and treatment of neural edema. Although perioperative steroid therapy has been used in patients undergoing acoustic neuroma removal, the efficacy of such therapy has not been previously documented. METHODS: A retrospective review of 169 patients who underwent acoustic neuroma surgery with (n = 75) or without (n = 94) a single dose of intraoperative corticosteroids was performed. Tumor size ranged from 0.4 cm to 6 cm (mean, 2.1; SD, 1.0) The translabyrinthine approach was used in 85% of the patients, and the middle cranial fossa approach was used in 13%. Data were analyzed for differences in postoperative facial function and complication rates. RESULTS: After controlling for differences in tumor size, no significant effects of steroid therapy were found for any of the outcome variables. CONCLUSIONS: This retrospective study showed no apparent benefit from intraoperative steroid use in acoustic neuroma surgery. A prospective, randomized, placebo-controlled trial should be performed to confirm these findings.     

Preoperative speech and pure-tone audiometry in four types of patients with acoustic neuroma

PURPOSE: The goal of this study was to compare pure-tone and speech audiometry in 4 groups of patients with confirmed unilateral acoustic neuroma in which auditory brainstem responses and transient-evoked otoacoustic emissions were either both normal, abnormal, or one of the tests was abnormal.Material and methods: This study was realized during a preoperative assessment of 65 patients (29 men, 36 women) from 25 to 78 years of age suffering from unilateral acoustic neuroma. The assessment, preceded by tympanometry, included recordings of auditory brainstem responses, transient-evoked otoacoustic emissions, pure-tone audiometry, speech recognition thresholds, and speech discrimination. RESULTS: Some discrepancies between objective and behavioral test results were noticed. Subjects with no otoacoustic emissions but present auditory brainstem responses did not show any significant difference in their speech scores as compared with subjects with both auditory brainstem responses and otoacoustic emissions. CONCLUSIONS: In summary, this study showed that comparable audiometric findings in acoustic neuroma patients can be found regardless of the presence of transient otoacoustic emissions (TEOAEs). TEOAEs are a good screening tool and have been used, like auditory brainstem-evoked responses, as a predictive measure before hearing preservation procedures but cannot predict the audiogram or give information about speech perception. The findings confirm that even if auditory brainstem responses are an extremely useful diagnostic tool for identifying acoustic neuroma, this test provides only giving pieces of information regarding auditory abilities. Also, the pure-tone audiogram gives useful information but has to be used in conjunction with speech audiometry to get an accurate picture of the patient's true auditory abilities.     

Unilateral acoustic neuromas in childhood without evidence of neurofibromatosis: case report and review of the literature.

A six-year-old female with a unilateral benign acoustic neuroma and no evidence of neurofibromatosis is presented. Review of the literature revealed only 16 cases of unilateral acoustic neuromas in children less than 15 years old. Children often do not appreciate hearing loss when compared with adults. As a result, they often present with larger tumors, thus adversely affecting outcome. The need for early diagnostic tests and a hearing-conservation surgical approach is emphasized. Routine follow-up imaging studies are crucial to rule out the development of a contralateral acoustic neuroma in neurofibromatosis-2 (NF-2).     

Impairments, disabilities, and handicaps after acoustic neuroma surgery

The measurement of a patient's health-related quality of life following acoustic neuroma surgery is important because the surgery itself can impose significant symptoms postoperatively. This study describes the most common problems experienced by the patients, using an open-ended questionnaire mailed to a series of 70 patients who had undergone acoustic neuroma surgery. Patient responses were classified by impairment, disability and handicap, according to the World Health Organization (WHO) classification. Results showed that this group of patients had a wide variety of symptoms and concerns, and particularly highlighted the relative importance of visual (49% of the patients) and psychosocial problems (34% of the patients) associated with surgery in contrast to tinnitus that seemed to be of minor importance. Open-ended questionnaires are useful in assessing outcomes from a quality of life perspective.     

ABR screening for acoustic neuromata: the role of rate-induced latency shift measurements.

The audiological assessment of patients considered 'at risk' for an acoustic neuroma is problematic when the patient has a severe hearing loss. The utility of ABR rate-induced latency shift (RLS) measurements was investigated in 189 patients who had passed a conventional assessment and 31 patients with an acoustic neuroma. A test based on the RLS of wave V using rates of 11.1 s-1 and 88.8 s-1 had a sensitivity of 89.5% and a specificity of 90.8% when applied with a dual interpretive criterion which included the loss of wave V at the higher rate. This test was included in an ABR screening protocol which had a sensitivity of 100% and a specificity of 97.9%. The RLS test requires no correction for age, sex, hearing loss or stimulus intensity and may be used in patients with severe hearing loss for whom other ABR tests are inappropriate.     

Acoustic neuroma ingrowth in the cochlear nerve: does it influence the clinical presentation?

We examined the clinical presentation in patients with a histologically proven ingrowth of the cochlear nerve by acoustic neuroma to see whether this differs from what is known from large acoustic neuroma series. In total, 85 acoustic neuromas had an en bloc dissection to study histologically the relation between the cochlear nerve and the acoustic neuroma. In 21 of these 85 specimens, there was histologic proof of invasion of the cochlear nerve by the tumor. For 13 of these 21 tumors, sufficient clinical data could be retrieved to describe the clinical presentation in these patients. We collected clinical data such as age, sex, presenting symptoms, duration of symptoms, tone audiograms, tumor size measurements and volumetric calculations, and latency interval data I-V of brain stem evoked response audiometry and calculated whether there was any correlation among those data. We also compared these clinical data with the data from some large acoustic neuroma series. No clear difference could be shown between the clinical presentation of acoustic neuroma patients with cochlear nerve ingrowth and the clinical presentations in large acoustic neuroma series. This outcome favors the theory that the hearing impairment in acoustic neuroma patients is mainly the result of compression on the vessels of the cochlea and/or on the cochlear nerve.     

Patient perception of comorbid conditions after acoustic neuroma management: survey results from the acoustic neuroma association

OBJECTIVES/HYPOTHESIS: Based on survey results of the Acoustic Neuroma Association, the patient ratings of the most difficult aspects of acoustic neuroma management were reported and a review of the literature was made regarding comorbid conditions associated with acoustic neuroma treatment and their impact on patient quality of life. STUDY DESIGN: Cohort study of 1940 patients who were members of the Acoustic Neuroma Association. METHODS: A detailed questionnaire was mailed to 2372 members of the Acoustic Neuroma Association to identify preoperative and postoperative symptoms, complications, and long-term effects on physical and psychosocial function. For 1940 respondents (81.8%) who reported the "most difficult aspect of the AN [acoustic neuroma] experience," the responses were analyzed by tumor size, surgical approach, and patient age and sex. Statistical analysis was performed using SPSS software. RESULTS: Respondents reported that the most difficult aspect of the acoustic neuroma experience was hearing loss (25.8%), followed by facial weakness (17.9%), eye problems (10.8%), and headache (10.5%). In order of frequency, men reported hearing loss, balance problems, perioperative surgical experience, and eye and facial weakness, and women reported hearing loss, facial weakness, eye problems, and headache. Facial weakness was a morbidity more often reported for men and women who had large tumors, who were young, or who had undergone the retrosigmoid approach. Balance dysfunction was significant in patients older than 75 years of age. In patients with small tumors, headaches and balance problems were frequently reported. CONCLUSION: In the large cohort study of patients with acoustic neuroma, perceptions regarding the impact of treatment illustrated why it is incumbent on physicians to understand the sentiments of patients with acoustic neuroma when counseling them and recommending optimal management strategies.     

Recovery from repeated sudden hearing loss with corticosteroid use in the presence of an acoustic neuroma.

Sensorineural hearing loss of sudden onset may be the presenting symptom in up to 14% of patients with acoustic neuroma. We present the first reported case of sudden hearing loss in an only hearing ear with recovery to normal levels after steroid therapy on four separate occasions. Evaluation revealed a 1.5-cm acoustic neuroma. After middle cranial fossa decompression, a fifth episode with recovery after steroid use was documented. A review of the recent literature is presented, emphasizing the possible causation of sudden sensorineural hearing loss with recovery to normal in patients with acoustic neuroma. Modalities of therapy for the dilemma of the acoustic neuroma in an only hearing ear are discussed, including surgery, radiotherapy, and chemotherapy. An aggressive approach to the evaluation of the cause of sudden hearing loss is suggested.     

The influence of the Internet on decision making in acoustic neuroma

OBJECTIVE: To determine the access to and the use of the Internet by acoustic neuroma patients as a medical information source, and the influence of the Internet on decision-making, as well as the patients' views on the quality of particular sites. MATERIALS AND METHODS: A retrospective 27-item questionnaire was sent to 138 consecutive acoustic neuroma patients diagnosed between 1997 and 2002. The study included patients treated by conservative, radiotherapeutic and surgical modalities. MAIN OUTCOME MEASURES: Patient demographics, the extent of Internet use as well as quality and quantity of available information. RESULTS: There were 86.95 per cent questionnaires available for analysis. Twenty-four per cent accessed the Internet to obtain information about acoustic neuromas. Ninety-seven per cent of patients said that the information provided in the clinic matched with the information obtained from the websites, 49 per cent said that the information obtained from the Internet did not influence decision making regarding acceptance of treatment of their tumour. Some patients said the Internet information was depressing, devastating, and they would never look up the Internet again for medical information. CONCLUSION: A significant proportion of our patients accessed the Internet for information. Caution should be exercised when advising patients regarding websites as the information on the Internet is often not controlled or checked for accuracy. Acoustic neuroma specialists and ENT surgeons in general should familiarize themselves with related websites so that patients can then be directed to high-quality sites.     

Acoustic neuroma: postoperative quality of life.

OBJECTIVE: Evaluating patients who have had surgical management of acoustic neuroma has relied heavily on the surgeon's viewpoint for determining success. However, the perspective of the surgeon may be different from that of the patient. Thus, a recent increased interest in terms of quality of life has been documented by the literature on this specific topic essentially through the use of a questionnaire. The objective of this paper was to review this topic in our series of patients operated on for acoustic neuroma to ascertain the personal and social impact that surgery has had on their lifestyle. DESIGN: This retrospective study was devoted to increasing statistics to provide more detailed and valid information during the counselling phase. METHODS: This study was carried out on 82 patients who underwent surgery for acoustic neuroma between 1988 and 1997. Each patient was recalled and assessed for his/her postoperative quality of life. Detailed information was requested on the initial postoperative facial, vestibular, and hearing functions; their evolution; and their social consequence. Finally, at the end of the interview, each patient was invited to give a final comment on his/her opinion regarding the outcomes of surgery and preoperative information. RESULTS: Facial function showed a grade I-III in 85.4% of cases, with postoperative neurovegetative dysfunction (taste and lacrimation) in 43%. Audiologic abnormalities (worsening hearing and tinnitus) were complained of in 90% and 57% of the cases, respectively. Twenty-three percent of the patients had various degrees of gait instability; 6% reported postoperative headache at 1-year follow-up. Social consequence (reduced work ability, vocational change, new education, state pension, etc.) was not influenced by surgery in 80%. CONCLUSIONS: Our experience is in general agreement with previously reported statistics. It is interesting to note that our patients exhibited more disturbances linked to the sensory component of facial nerve. In contrast, dysequilibrium had a less negative influence. These outcomes suggest the importance of thorough preoperative counselling in candidates for surgery for acoustic neuroma in order to motivate them and, at the same time, to reduce their psychological discomfort.     

Otosclerosis masking coexistent acoustic neuroma

The coexistence of an acoustic neuroma with otosclerosis can prove to be a great diagnostic dilemma. In such cases, the diagnosis of acoustic neuroma is usually delayed while more common causes of sensorineural hearing loss associated with otosclerosis or its surgery are considered. Any asymmetric progression of a sensorineural loss or shift in discrimination after stapes surgery, whether sudden or gradual, should provoke suspicion of a second pathologic process. These include perilymph fistula, labyrinthine otosclerosis or ischemia, and acoustic neuroma. The use of auditory brainstem response and acoustic reflex testing and various imaging techniques is essential for accurate diagnosis. This paper includes two cases that demonstrate this dual pathology, bringing the total to 15 such cases reported in the literature. The purposes of this paper are to alert the clinician to the diagnostic problem of acoustic neuroma coexisting with otosclerosis and to propose a means of evaluating these patients.     

Preoperative, intraoperative, and postoperative auditory evaluation of patients with acoustic neuroma

This article is a concise clinical review of preoperative, intraoperative, and postoperative auditory evaluation of patients with acoustic neuroma. The author describes behavioral audiometry, auditory brainstem response, and otoacoustic emissions for preoperative evaluation; auditory brainstem and direct eighth-nerve intraoperative monitoring for intraoperative evaluation; and touches on postoperative auditory assessment.     

神经耳科学检查对听神经瘤的诊断意义

目的：探讨神经耳科学检查对听神经瘤的诊断意义。方法：对１３例听神经瘤行纯音测听,声导抗,眼震电图,听性脑干诱发电位（ＡＢＲ）,耳蜗电图及面神经电图等神经电生理检查。结果：患侧纯音听阈１例正常,另４例２ｋＨｚ以下在正常范围,声导抗镫肌反射试验结果不一,冷热试验８例患侧半规管麻痹,均伴有一项或多项视－前庭眼动眼震异常;ＡＢＲ２例未能引出,敏感度为９０．９％;７例面神经电图异常;３例面神经电图异常;３例     

Acoustic Neuroma: Deterioration of Speech Discrimination Related to Thresholds in Pure-Tone Audiometry

Pure-tone and speech audiometry were performed in 231 patients with a unilateral acoustic neuroma. Tumor sizes were obtained through imaging. Audiometric parameters, such as the mean pure-tone thresholds, the maximum discrimination, the slope of the speech audiogram, the roll-over index and the difference between the speech reception threshold and the Fletcher index, were studied and compared with data in the literature. Results showed that patients with an acoustic neuroma have worse speech discrimination than can be expected from the pure-tone audiogram. However, the results presented here indicate that hearing impairments nowadays are not as severe as those described in earlier studies. More patients with a unilateral acoustic neuroma are detected, including even those with a minor hearing impairment. The roll-over index is not characteristic for patients with an acoustic neuroma.     

听神经瘤患者术前面神经及耳蜗神经显影技术

听神经瘤是最常见的桥小脑角良性肿瘤,手术可引起面瘫、听力下降等并发症,术前定位面神经、耳蜗神经可降低其发生率。本文对近年来发展的颅内神经显影技术做一综述,主要集中于听神经瘤患者的面神经、耳蜗神经定位手段。     

Acoustic neuroma: deterioration of speech discrimination related to thresholds in pure-tone audiometry

Pure-tone and speech audiometry were performed in 231 patients with a unilateral acoustic neuroma. Tumor sizes were obtained through imaging. Audiometric parameters, such as the mean pure-tone thresholds, the maximum discrimination, the slope of the speech audiogram, the roll-over index and the difference between the speech reception threshold and the Fletcher index, were studied and compared with data in the literature. Results showed that patients with an acoustic neuroma have worse speech discrimination than can be expected from the pure-tone audiogram. However, the results presented here indicate that hearing impairments nowadays are not as severe as those described in earlier studies. More patients with a unilateral acoustic neuroma are detected, including even those with a minor hearing impairment. The roll-over index is not characteristic for patients with an acoustic neuroma.     

Acoustic neuroma: Correlation among tumor size,symptoms, and patient age

Due to improved diagnostic techniques, acoustic neuromas more frequently are detected at an early stage. Subsequent treatment depends on such factors as expected tumor growth rate, tumor size, and patient age. The natural history of acoustic neuromas is still uncertain: This study was performed to examine possible correlations among tumor size, patient age, signs and symptoms, and duration of symptoms. The study included 164 patients with an acoustic neuroma who were treated at University Hospital Nijmegen, The Netherlands, over a period of 13 years. Comparisons were made between the findings of this study and the reports in the literature. No support was found for any of the correlations mentioned in other studies, and no relationships could be demonstrated between the parameters evaluated in this study. The authors therefore recommend that treatment policies be based only on well-established correlations.     

Recurrence of acoustic neuroma after incomplete resection

OBJECTIVE: To determine the risk of recurrent tumor in patients after incomplete resection of acoustic neuroma. STUDY DESIGN: Retrospective case review. SETTING: A tertiary referral center. PATIENTS: Thirty-nine patients were identified who underwent incomplete resection of acoustic neuroma between January 1988 and December 1993, and had a minimum follow-up of 3.5 years, at a mean of 6.2 years (range 3.5-10.2 years). INTERVENTION: Regular follow-up. using either computed axial tomography or magnetic resonance imaging yearly. MAIN OUTCOME MEASURES: Growth of residual tumor as determined by the increase in its greatest dimension on follow-up imaging studies and the necessity for additional treatment. RESULTS: Tumor regrowth occurred in 17 patients (44%). Ten patients (26%) required additional treatment during the follow-up period. CONCLUSION: This study suggests that incomplete resection of acoustic neuroma is associated with a significant risk of recurrent tumor requiring subsequent intervention.