Cochlear implantation concurrent with translabyrinthine acoustic neuroma resection

OBJECTIVES/HYPOTHESIS: Cochlear implants provide successful auditory rehabilitation for patients with profound sensorineural hearing loss who do not derive at least marginal benefit from conventional hearing aids. Patients with neurofibromatosis type 2 can present with bilateral profound sensorineural hearing loss caused by bilateral vestibular schwannomas. Auditory rehabilitation in these patients can be challenging. We present the case of one such patient who underwent a concurrent translabyrinthine vestibular schwannoma resection and cochlear implantation in the same ear. STUDY DESIGN: A case report and review of the literature. METHODS: Review the patient's medical record and MEDLINE literature search. RESULTS: The patient presented with a relatively small tumor that was situated in the fundus of the internal auditory canal with intralabyrinthine extension. Postoperative performance with implant stimulation was in the higher range of that for other cochlear implant patients. CONCLUSIONS: To the best of our knowledge, this is the first case reported of simultaneous cochlear implant and translabyrinthine acoustic neuroma resection in the same ear of a patient with neurofibromatosis type 2.     

Management of intralabyrinthine schwannomas

OBJECTIVES: Our protocol to manage the intralabyrinthine schwannoma (ILS). METHODS: Retrospective chart review of 7 consecutive patients managed for ILS. RESULTS: Five patients underwent surgical removal of the lesions and none experienced significant complications or recurrent disease. One patient refused surgical treatment and was closely followed by serial MRI scans with no signs of tumor growth. One patient is presently managed conservatively due to a good hearing. CONCLUSIONS: Diagnosis of ILS is based on high resolution MRI scans and should be included in the differential diagnosis of patients investigated for cochleovestibular symptoms. Treatment modality of ILS is controversial and depends patients' age, severity of vertigo and hearing loss. In the authors' experience surgery is indicated in all cases with invalidating vertigo and in the young patients with severe hearing loss. Conservative strategy is advised in older patients and in cases with preserved good hearing and no invalidating vertigo. These patients must be followed up using high resolution MRI because of the risk of tumor growth into the internal auditory canal. While tumors with exclusive involvement of the inner ear may be removed by means of a completely extradural approach, tumor growth with involvement of the internal auditory canal dictates the necessity of opening the dura exposing the patients to the potential risks associated with the procedure.     

Can cochlear function be preserved after a modified translabyrinthine approach to eradicate a huge cholesteatoma extending to the petrous apex?

The objective of the present study was to show that the modified translabyrinthine approach with partial ablation of the labyrinths is useful for preserving hearing in our experience involving three clinical cases with huge cholesteatomas extending to the petrous apex. A retrospective analysis of patient medical records was done in a tertiary referral medical center. All three patients studied had huge cholesteatomas extending to the petrous apex and were treated surgically with a modified translabyrinthine approach between October 2005 and December 2006. The modified translabyrinthine approach was used in all patients. Long-term hearing results were obtained. The cholesteatoma sac was removed completely in all patients. Pure tone audiometry demonstrated that the hearing had been saved in two patients. We concluded that the modified translabyrinthine approach is useful for preserving hearing postoperatively when a huge cholesteatoma exists involving the petrous region or a vestibular schwannoma in the internal auditory canal or cerebellopontine angle.     

Postoperative magnetic resonance imaging findings after transtemporal and translabyrinthine vestibular schwannoma resection

OBJECTIVES/HYPOTHESIS: Magnetic resonance imaging (MRI) has become the investigation of choice to follow up patients after vestibular schwannoma resection. STUDY DESIGN: Retrospective. METHODS: Postoperative MRI findings of 70 patients after vestibular schwannoma resection through a transtemporal (n = 48) and a translabyrinthine (n = 22) approach were reviewed. Time-dependent changes in intensity, size, and shape of enhancement in the internal auditory canal before and after contrast administration, postoperative temporal lobe gliosis, and changes of fat grafts were evaluated. RESULTS: After vestibular schwannoma resection, all patients showed signal enhancements in the internal auditory canal ranging from a faint to high signal intensity in the first postoperative MRI, 3 to 6 months after surgery. In the next MRI at 12 to 24 months after surgery, 30 patients (43%) showed a decreased signal, 35 patients (50%) a stable enhancement, and 5 patients (7%) an increased enhancement in the internal auditory canal depicted as an intense nodular or mass-like pattern. In patients with decreased or stable enhancement, a residual tumor could be excluded in the following MRI scans, whereas in all patients with increased enhancements after 12 to 24 months, signal enhancement further increased and residual tumors were detected. Different degrees of temporal lobe gliosis were found in 15 of 48 cases (31%) after transtemporal tumor removal. Enhancement of fat grafts used in 22 cases decreased to different degrees in 14 cases (64%). CONCLUSIONS: Differentiation of residual tumor from scar tissue in the internal auditory canal after vestibular schwannoma resection requires close, long-term follow-up. Nodular and progressive enhancements in the internal auditory canal indicate residual tumor. Linear enhancement in the internal auditory canal has been found to be a common finding after vestibular schwannoma resection not associated with residual tumor.     

Acoustic schwannoma presenting as a tumor of the external auditory canal. Case report

An acoustic neurinoma involving the internal auditory canal, the vestibule, the cochlea, the middle ear, and extending into the cerebellopontine angle and the external auditory canal, is described in a 56-year-old woman. An initial episode of vertigo was followed by a 27-year history of progressive unilateral hearing loss leading to complete deafness and areflexia with central compensation. The tumor was removed by a two-step surgical procedure, and the histologic features were those of a schwannoma.     

Modified translabyrinthine approach and hearing preservation

OBJECTIVES/HYPOTHESIS: In 1991, the translabyrinthine approach was modified by sealing the vestibule with bone wax, which allowed preservation of the hearing function in one patient. The present study aimed specifically at evaluating the effectiveness of the modified translabyrinthine approach in preserving hearing function in a group of patients with vestibular schwannoma that involved the internal auditory canal. STUDY DESIGN: Prospective study. METHODS: The series consisted of 12 patients with vestibular schwannoma (average age, 49.7 y). The schwannoma was smaller than 2 cm in all patients who had surgery. The patients accepted for the study were required to have preserved hearing function. RESULTS: None of the patients has shown signs of persistence or tumoral relapse on postoperative magnetic resonance imaging. Immediately after surgery, the entire group had excellent facial functionality. Six patients had maintained their hearing function (four in Class 1 and two in Class 2 according to the Gardner-Robertson scale) at the last follow-up after surgery. A patient during follow-up noted fluctuating hearing contemporarily with a tinnitus in the ear that had maintained its hearing, which was attributable to an endolymphatic hydrops. Three of the six patients with preserved hearing complained of persistent tinnitus. None of the patients had any of the complications or consequences of cerebellopontine surgery. CONCLUSION: In our patients, Class 1 or 2 hearing was preserved in 50% of the patients, with no persistence or tumoral relapse. The follow-up has obviously been short, but the first results are encouraging and deserve to be studied further in a more comprehensive survey.     

The value of enhanced magnetic resonance imaging in the evaluation of endocochlear disease.

BACKGROUND: Gadolinium-enhanced magnetic resonance imaging (GdMRI) is routinely used in the evaluation and management of suspected retrocochlear pathology such as vestibular schwannoma. However, its value in the evaluation and diagnosis of cochlear pathology associated with sensorineural hearing loss (SNHL) has been less clear. STUDY DESIGN: Retrospective review of case histories and imaging studies of patients with SNHL and cochlear enhancement on GdMRI diagnosed between 1998 and 2000. RESULTS: Five patients with SNHL who required gadolinium administration to establish the diagnosis of endocochlear disease were identified. Diagnosed lesions included an intralabyrinthine schwannoma, intracochlear hemorrhage, radiation-induced ischemic change, autoimmune labyrinthitis, and meningogenic labyrinthitis. In these illustrative cases, the GdMRI demonstrated intrinsic high signal or contrast enhancement within the cochlea and labyrinth in the absence of a retrocochlear mass. In one patient with meningogenic labyrinthitis, cochlear enhancement on MRI led to prompt cochlear implantation before the potential development of cochlear ossification. CONCLUSION: Our experience suggests that GdMRI plays a crucial role in the diagnosis of cochlear pathology associated with sensorineural hearing loss and may directly impact patient management.     

Intra-labyrinthine schwannoma: two-cases report

Intralabyrinthine schwannomas are uncommon tumours that arise from neural elements in distal branches of the 8th cranial nerve thus they are confined to or have arisen from the vestibule, the semi-circular canals, or the cochlea. The most common presenting symptom is progressive sensory neural hearing loss with or without tinnitus and vestibular symptoms. The diagnostic procedure of choice is gadolinium-enhanced magnetic resonance imaging. Most of these patients can be managed with observation. The indications for surgery are limited. We present 2 patients with a diagnosis of intralabyrinthine schwannoma. A discussion of the management of the intralabyrinthine schwannoma follows.     

Hearing preservation after translabyrinthine approach performed to remove a large vestibular schwannoma

We report the case of a 27-year-old woman from whom a left vestibular schwannoma (grade IV) was removed by a translabyrinthine approach. The initial period was uneventful except for a few days of vertigo. This patient had no facial paresis (House-Brackman grade I). She was seen 1, 3, 6 and 12 months after operation and reported a sensation of hearing in the left ear. The audiological studies showed a left medium hearing loss. At the 1-year follow-up visit, her hearing status was unchanged. A hearing aid was fitted and functioned satisfactory. At the 5-year follow-up visit, audiometry studies were unchanged. Our case demonstrated that some hearing preservation could be obtained even if the vestibular schwannoma was large and excised by a translabyrinthine approach. Hearing with the help of a good hearing aid allowed a satisfactory function in this case. We believe that it is possible to preserve some hearing after translabyrinthine approach even if no care was taken to preserve the membraneous labyrinth and the loss of endolymph and even if the vestibular schwannoma was large. However, further experimental studies are needed to determine and understand the mechanisms of hearing preservation in this case.     

Facial nerve schwannoma in the inner auditory canal and geniculate ganglion

BACKGROUND: Schwannoma of the vestibular nerve is the most common tumor found in the inner auditory canal. If a schwannoma of the facial nerve is found unexpectedly during surgery, the original surgical plan may have to be changed. In our series, we describe the symptoms, diagnostic procedures and therapy of this infrequent, benign tumor. In particular, we want to analyse the influence of diagnostic techniques, such as magnetic resonance tomography and electrophysiology, on the diagnosis of these tumors. PATIENTS: Between 1975 and 2001, we diagnosed 17 cases of facial nerve schwannoma in the inner auditory canal or the geniculate ganglion. All patients were treated surgically. In 16 cases, we used the enlarged middle fossa approach and in the remaining patient the translabyrinthine approach was used. RESULTS: In 11 cases, the facial nerve could be saved but in six the nerve had to be rebuilt with a transplant. During the first years of our study, palsy of the facial nerve was a frequent finding. In the later years, a hearing impairment and tinnitus became the most frequent symptoms. CONCLUSIONS: Advances in magnetic resonance imaging have, in many cases, facilitated the differentiation between schwannomas of the facial nerve and the vestibular nerve over the last years. Signal enhancement at the geniculate ganglion is important for the diagnosis of facial nerve schwannoma. In individual cases, we found significant findings using electrophysiological procedures. In three cases, the temporal delay was elongated. Based on these findings, the therapeutic procedures can be discussed together with the patients.     

Translabyrinthine vestibular schwannoma resection with simultaneous cochlear implantation

Objectives: (1) Report a rare case of translabyrinthine resection of a sporadic vestibular schwannoma (VS) and concurrent cochlear implantation (CI). (2) Discuss pre-, intra-, and post-operative considerations in this unique patient population. (3) Describe surgical and audiologic outcomes reported in this population.

Methods: Case report and review of the literature. PubMed search ‘Cochlear Implantation’[Mesh] AND (‘Neuroma, Acoustic’[Mesh] OR ‘VESTIBULAR SCHWANNOMA’[All Fields] OR ‘SCHWANNOMA’[All Fields]) limited to humans and English language. Returned 64 search results, abstracts and references of relevant papers reviewed.

Results: A 75-year-old male with longstanding history of slowly progressive severe hearing loss and tinnitus presented for evaluation of worsening imbalance, vertigo, and nausea. Workup revealed a 7?mm right intracanalicular mass on MRI concerning for vestibular schwannoma. Audiogram showed bilateral, symmetric, severe-to-profound sensorineural hearing loss, with poor open-set speech comprehension while bilaterally aided. He underwent successful concurrent right translabyrinthine resection of his VS with complete preservation of the cochlear nerve and uncomplicated cochlear implantation.

Discussion: Literature review revealed few previous reports of simultaneous VS and CI. The vast majority of these were in patients with neurofibromatosis Type 2 in whom auditory outcomes were poor. This patient represents one of the few cases of concurrent translabyrinthine tumor removal and CI for a spontaneous VS.

Conclusion: Single-stage cochlear implantation and translabyrinthine tumor resection is a feasible and safe option to consider for auditory rehabilitation in rare situations.     

A comparison of retrosigmoid IAC, retrolabyrinthine, and middle fossa vestibular neurectomy for treatment of vertigo

A new procedure, the retrosigmoid internal auditory canal (IAC) vestibular neurectomy has been developed and presented. It involves a 3-cm retrosigmoid craniotomy removing the posterior wall of the IAC to the singular canal, with transection of the superior vestibular nerve and posterior ampullary nerve. This produces a complete denervation of the vestibular labyrinth and preserves the patient's hearing. All ten patients with Meniere's disease had their vertigo cured. Hearing was preserved to within 11 dB of the preoperative pure tone average in 9 of 10 cases. There were no serious complications, no cases of facial paralysis, and no cases of total hearing loss. These results compare favorably with the MFVN and the RVN. The retrosigmoid IAC vestibular neurectomy is an important improvement in the evolution of vestibular neurectomy for the treatment of vertigo.     

Controversies in building a management algorithm for vestibular schwannomas

PURPOSE OF REVIEW: The present review examines the various mainstream treatment options, benefits and risks, and controversies involved in developing a management algorithm for treatment of vestibular schwannoma. RECENT FINDINGS: Advances in microsurgery and radiosurgery have made tremendous contributions to management of vestibular schwannoma; however, considerable controversy still exists. The auditory and facial nerve functional outcomes have improved with use of intraoperative monitoring for vestibular schwannoma removal and with lower radiosurgery doses; however, risks to the facial and auditory nerves still exist. Observing vestibular schwannomas for growth with serial magnetic resonance imaging is an increasingly popular option for small vestibular schwannomas that allows patients to enjoy hearing and facial function. SUMMARY: The risks and benefits of each treatment option must be weighed for each patient, and management decisions regarding vestibular schwannomas should be individualized for each patient depending on tumor anatomy, patient preferences, and symptoms.     

Magnetic resonance appearance of the inner ear after hearing-preservation surgery.

OBJECTIVE: To determine whether the appearance of the inner ear on T2-weighted follow-up magnetic resonance imaging correlates with hearing status after hearing-preservation surgery for vestibular schwannoma. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary referral medical center. PATIENTS: The study includes patients undergoing hearing-preservation surgery for vestibular schwannoma from 1998 to 2003. INTERVENTION: Diagnostic evaluation with magnetic resonance imaging and audiometric evaluation. MAIN OUTCOME MEASURES: Hearing results as reported in charts was correlated with appearance of membranous labyrinth on T2-weighted magnetic resonance images obtained at least 1 year after surgery. RESULTS: Twenty-nine patients were identified, 16 of whom satisfied the inclusion criteria. All 16 of the patients underwent middle fossa removal of vestibular schwannoma. Serviceable hearing according to American Academy of Otolaryngology-Head and Neck Surgery criteria was preserved in eight patients (50%). Of the eight patients without serviceable hearing, six had the cochlear nerve sacrificed at the time of surgery. All patients with serviceable hearing had normal appearing cochleovestibular signal on T2-weighted images, whereas six of eight patients (75%) with no hearing or poor hearing had abnormal low signal in the inner ear, suggesting inner ear ossification. The positive predictive value of a normal labyrinth for preserved hearing was 90%, whereas the negative predictive value of an abnormal labyrinth for no hearing was 100%. All but one patient who had the cochlear nerve sacrificed showed abnormal morphology of the labyrinth on T2-weighted magnetic resonance imaging. CONCLUSION: We describe the T2-weighted magnetic resonance findings after hearing-preservation surgery for acoustic tumor removal. Loss of inner ear signal on T2-weighted images correlates with loss of hearing postoperatively, whereas preserved inner ear signal correlates with hearing preservation after middle fossa surgery for vestibular schwannoma removal.     

Solitary metastasis of lung carcinoma to the internal auditory canal

We report a case of solitary metastasis of lung carcinoma into the internal auditory canal. On admission, the 60-year-old patient was complaining about a rapidly developing hearing loss with ipsilateral facial nerve paralysis. Magnetic resonance imaging revealed an intracanalicular tumor, which was interpreted as vestibular schwannoma. After tumor resection, the histopathologic examination revealed a metastasis of a squamous cell carcinoma. Computed tomographic scan and bronchoscopy identified an asymptomatic primary pulmonary neoplasm.     

Clinical picture of vestibular schwannoma

PURPOSE: To characterize the clinical picture with vestibular schwannoma, we retrieved 122 patients with vestibular schwannoma from the vestibular unit of the Helsinki University Central Hospital. PROCEDURES: The patients filled out a questionnaire concerning their symptoms, earlier diseases, accidents, and the use of tobacco and alcohol. This information was then completed with results of audiometric, neurotologic and imaging studies. The data were prospectively stored to the database of neurotologic expert system called ONE. RESULTS: The average tumor size was 21 mm. Most of the patients had hearing loss (94%) and tinnitus (83%) but only half of them (49%) had vertigo attacks. The most common initial symptom was hearing loss combined with tinnitus (34%, n=44). Vertigo only was the initial symptom for 12 patients. The mean duration of a vertigo attack was from 5 min to 4 h and the intensity of the attack was regularly mild (37%) or moderate (32%). The vertigo of the vestibular schwannoma patients differed from vertigo in other diseases by the absence (63%) or low intensity (18%) of nausea. Spontaneous nystagmus was present in 56 patients (46%), and caloric asymmetry (>25%) was observed in 66% (n=69). Caloric asymmetry increased with tumor size. The prevalence of headache was 18% (n=21). Sudden slips seldom (7%) occurred. CONCLUSION: Hearing loss and tinnitus are the main symptoms of vestibular schwannoma. Only half of patients have vertigo. Screening to detect vestibular schwannoma is more yielding in sudden deafness patients rather than in patients with Meniere's disease.     

Intralabyrinthine schwannomas: symptoms and managements

OBJECTIVE: To describe the characteristic presentations, radiologic findings and managements of the intralabyrinthine schwannomas. METHOD: Retrospective review of patient records, their managements, and review of the literature. RESULT: Four patients with a variety of otologic symptoms including hearing loss, vertigo, and tinnitus were found to have a schwannomas involving the labyrinth. In all cases, the inner ear lesions were preoperatively identified on magnetic resonance imaging, and the surgical removals were performed in all patients without serviceable hearing. The patients experienced improvement in their vertigo and tinnitus after surgery. Two patients were implanted the Bone-Anchored Hearing Aid (BAHA) to reconstruct the pseudo-stereophonic hearing. CONCLUSION: Intralabyrinthine schwannomas are the rare tumours in the otology. The tumour can be removed by surgical approach, but we do not propose surgical excision for the patients with serviceable hearing. BAHA can give patients a post-operative monaural pseudo-stereophonic hearing.     

Intracochlear schwannoma extending to vestibule

Intralabyrinthine schwannomas are benign tumors arising de novo from the perineural Schwann cell sheath of the intralabyrinthine branches of the vestibulocochlear nerve. The development of magnetic resonance imaging (MRI) has significantly increased the diagnosis of these tumors. Intralabyrinthine schwannomas can be sub-classified into seven groups according to the structures of the inner ear that are affected. The management strategy for intralabyrinthine schwannoma is regular monitoring with MRI, as the tumor grows slowly. In cases where the tumor growth is documented on serial MRI or disturbing vestibular symptoms are present, surgical removal can be considered. The surgical approach varies based on tumor location and size. We report a case of intravestibulocochlear schwannoma causing vertigo that developed from an intracochlear tumor during MRI. We successfully removed the tumor via the transotic approach.     

Intracanalicular facial nerve schwannoma.

OBJECTIVE: To investigate the capability of preoperative evaluations in predicting the precise anatomic origin of intracanalicular tumors. STUDY DESIGN: We conducted a retrospective case review. SETTING: Tertiary referral center. PATIENTS: A total of 11 patients (8 men and 3 women, 26-70 years old) with intracanalicular tumors who were treated surgically were included. INTERVENTIONS: Pure-tone average, auditory brainstem response, caloric test, and temporal magnetic resonance imaging were done in all 11 patients. Electroneuronography has only been performed since 2003, and only 3 patients were evaluated. MAIN OUTCOME MEASURE: Preoperative symptoms, pure-tone average, auditory brainstem response, caloric test, electroneuronography, and magnetic resonance imaging were compared between patients with facial nerve schwannomas and patients with vestibular schwannomas. RESULTS: Postoperatively, facial nerve schwannomas were diagnosed pathologically in 2 (18%) of 11 patients. There were not any clues suggesting facial nerve schwannoma in preoperative evaluations. CONCLUSION: A facial nerve schwannoma may be misdiagnosed as a vestibular schwannoma, especially when the tumor is confined to the internal auditory canal. There are no useful preoperative evaluation tools in predicting the precise nerve origin of intracanalicular tumors. These emphasize the need to fully inform the patient preoperatively.     

Case report and discussion of hearing preservation after translabyrinthine excision of small acoustic tumors

OBJECTIVE: Since 1991, three separate reports have shown how hearing may be salvaged after translabyrinthine excision of small acoustic tumors. The authors submit yet another report of a complete translabyrinthine excision of a 1.4-cm intracanalicular acoustic tumor with modest hearing preservation. An attempt is made to retrace the steps of the operation and recognize and discuss what particular events may have safeguarded the viability of the cochlea. With the availability of cochlear implantation, there should be added incentive to preserve the cochlear neurones if hair cells cannot be saved. STUDY DESIGN: The study design was a retrospective case review. SETTING: The study was conducted at a primary care hospital. INTERVENTION: Therapeutic and rehabilitative measures were performed. MAIN OUTCOME MEASURES: Hearing preservation was measured. CASE REPORT: A 55-year-old woman presented with a left-sided hearing loss and a 1.4-cm left acoustic tumor completely filling the internal auditory canal (speech reception threshold [SRT] 30 dB, discrimination [Pb] 28%). A successful translabyrinthine excision of the tumor was performed in November 1995. A 1-year postoperative audiogram showed a mixed hearing loss in the left ear with SRT 85 dB and Pb 0%. Average pure-tone threshold for 500 Hz, 1 kHz, and 3 kHz was 50 dB and aided SRT 40 dB with Pb 64%. Postoperative magnetic resonance imaging confirmed complete excision of the tumor. CONCLUSION: An exceptional case of hearing preservation after translabyrinthine excision of a small acoustic tumor illustrates how it may be possible to preserve cochlear hair cells and neurones simultaneously in certain selected cases. A review of the surgical events shows the value of sealing the cochlear duct with bone wax, selectively removing the vestibular nerves with the tumor by sharp dissection, and safeguarding the meatal segment of the anterior inferior cerebellar artery by a limited dural incision.