Fluctuating hearing loss in lipoma of the cerebellopontine angle

Two cases of lipoma of the cerebellopontine angle are presented. Both of them showed fluctuating hearing loss, and one case exhibited Menière-like symptoms. In one of the cases, continued clinical surveillance is considered in view of a high chance of postoperative morbidity.     

Preservation of hearing in the surgical removal of cerebellopontine angle tumors

It is claimed that postsurgical hearing preservation is possible in about 5 to 8 per cent of cases of acoustic neuroma. Even with small tumors, hearing preservation can be accomplished in about half of the patients who are fortunate to have anatomic integrity of facial and cochlear nerves, as well as intact inner ear blood supply at the end of the surgical procedure. Monitoring of seventh and eighth nerve function through evoked potentials may be important. On the other hand, even if evoked potentials are preserved during surgery with wave V latency and amplitude similar to preoperative recording, hearing may still be completely lost during the immediate postoperative period. There is no predictable pattern that assures postoperative preservation of hearing. In Case 2, the seventh and eighth nerves as well as the inner ear blood supply were carefully dissected and anatomically and electrophysiologically preserved during the intraoperative period. At the end of the surgical procedure, the evoked potentials were the same as preoperatively. Nevertheless, the patient ended up with no detectable hearing postoperatively. We feel that the suboccipital-retrosigmoid transcanal approach can be safely used for the removal of cerebellopontine angle tumors of all sizes. We believe the argument that "only the translabyrinthine approach can accomplish total tumor removal" is not valid. No complications have been attributed by having the patient in the semisitting position. Older patients, who cannot tolerate the semisitting position, are operated on while in the park bench position. Planned subtotal removal of a CPA tumor is done with the patient in the supine position (transmastoid-retrolabyrinthine or retrosigmoid). The relationship between the otologic surgeon and neurosurgeon is very important. The surgical approach used should be selected on the basis of the combined experience of the surgical team. Finally, an attempt should be made to preserve facial nerve function and hearing in all suitable patients. The postoperative course using the suboccipital-retrosigmoid approach is usually benign, and the patients are discharged from the hospital between 7 and 10 days following surgery. The translabyrinthine approach, in our opinion, should be reserved for smaller lesions in patients with anacusis or with residual hearing that is not worth saving.     

Sudden hearing loss

Sudden sensorineural hearing loss is a medical emergency in search of an appropriate treatment. Almost all aspects of this disease process are disputed in the literature. The natural course of the disease process has not been well defined, although spontaneous recovery in a percentage of patients appears well accepted. Little scientific data exist to develop an evidence-based treatment protocol. The more common elements of treatment in the United States include oral steroid therapy, transtympanic steroid therapy, and potentially oral antiviral therapy. Other therapies are used with great frequency, and their potential should not be discounted.     

Diagnosis of cerebellopontine angle tumors.

Between 1980 and 1990, 9,176 patients suffering from otoneurological disorders were investigated in our clinic. Sixty-six (0.72%) internal auditory canal or other cerebellopontine angle tumors (CPAT) were diagnosed. Brainstem auditory evoked potentials (BAEP), interaural time discrimination, and magnetic resonance imaging (MRI) revealed to be the most sensitive and efficient tests for the detection of CPAT. However, the investigation of otoneurological symptoms cannot be limited to BAEP and MRI on the a priori of a hypothetical CPAT. Electrophysiologic tests such as impedancemetry, and electronystagmographic testing are also needed to elucidate the many causes of otoneurological symptoms.     

Sudden sensorineural hearing loss and hemodialysis

The etiology of sensorineural hearing loss (SNHL) associated with renal failure and hemodialysis is controversial. Possible mechanisms include a shared antigenicity between the kidney and the labyrinths, osmotic alteration caused by hemodialysis, and the ototoxic effect of diuretics. We present 2 cases of SNHL associated with renal failure and its treatment. One patient was a 35-year-old man who developed profound SNHL after 5 sessions of hemodialysis, and the other was a 36-year-old woman who developed severe to profound SNHL after 7 sessions. It is our impression that both hearing losses might have been attributable to osmotic disequilibrium in the labyrinth or to an acute labyrinthine injury caused by contamination of the blood by the degraded product of an old cellulose acetate hemodialyzer membrane; the hemodialyzer had been in use for 15 years.     

Unusual regression of a sudden-onset sensorineural hearing loss in a patient with cerebellopontine angle pathology

This is a report of a patient with small internal acoustic canal pathology presenting as a sudden-onset sensorineural hearing loss. Initially the patient received non-specific empirical medical therapy and the sudden-onset sensorineural hearing loss recovered rapidly. Regression of the hearing loss, despite no change in magnetic resonance imaging (MRI) findings after the medical treatment is documented and discussed.     

Steroid responsive fluctuating sensorineural hearing loss due to juvenile pilocytic astrocytoma involving the cerebellopontine angle

Tumors of the cerebellopontine angle (CPA) are common and represent up to 10% of all intracranial tumors. Rarely, intrinsic brainstem tumors can involve the CPA and present with auditory symptoms typical of CPA tumors such as hearing loss, vertigo and tinnitus. We report on a rare case of an intrinsic brainstem neoplasm presenting with steroid responsive fluctuating sensorineural hearing loss in a child. The patient initially presented with an acute worsening of an unilateral sensorineural hearing loss, without additional symptoms, that responded to oral steroids. Otoacoustic emission testing demonstrated normal outer hair cell function suggesting retrocochlear pathology. Magnetic resonance imaging with contrast enhancement revealed an intrinsic neoplasm of the middle cerebellar peduncle impinging on the 7th/8th neurovascular bundle within the CPA. The patient underwent gross total resection of the juvenile pilocytic astrocytoma via retrosigmoid craniotomy and remains disease free at 2 years postoperatively. This case highlights that suspicion of central nervous system pathology should be heightened in the presence of steroid responsive, fluctuating sensorineural hearing loss with normal outer hair cell function.     

Diagnostic problems of rare cerebellopontine angle tumors

Astrocytoma (neuroepithelial tumor) determine about 25% all the cerebroma but their original location in cerebellopontine angle is seldom. In case of this kind of tumors in this place, the symptoms can be non-characteristic and similar to these, which appear in the acoustic neurinoma. The most important in case of this diagnosis is both that this tumors can infiltrate of the brain tissues and the fact that they can transformate toward the anaplastic astrocytoma or glioblastoma multiforme (very malignant tumors). MATERIAL AND METHODIC: A rare case of astrocytoma presenting as a cerebellopontine angle tumor is discussed. The special characteristics of this tumor and unusual clinical course are disscused. CONCLUSION: The early diagnosis of the astrocytoma increases the patient's chance on convalescence and limits extension of the operation, and consequently of the neurological complication.     

Transapical extension in difficult cerebellopontine angle tumors

The transapical extension of the enlarged translabyrinthine approach is aimed at making the removal of certain tumors of the cerebellopontine angle simpler and with less morbidity. The extension is classified into 2 types--type I and type II--based on the extent of bone drilling around the internal auditory canal. Type I extension involves drilling for 300 degrees to 320 degrees around the canal and is indicated for large or giant vestibular schwannomas and vestibular schwannomas with significant extension anterior to the internal auditory canal. Type II extension entails complete removal of the bone around the canal for 360 degrees and is indicated for meningiomas of the posterior surface of the petrous bone extending anterior to the internal auditory canal. The extension allows better control over the anterior pole of the tumor, the displaced facial nerve, the prepontine cistern, and the venous vascularity of the cerebellopontine angle. The aim of this report is to present our experience with this extension.     

Sudden hearing loss induced by acoustic neuroma: Significance of small tumors

In our series of 111 patients operated on for acoustic neuroma from 1972 to 1990, 21 (18.9%) had sudden hearing loss. The 21 tumors involved were comprised of 9 small, 5 medium, and 7 large tumors. Emphasis is placed on the fact that even a small tumor has the potential to produce sudden hearing loss (SHL) and that the possibility of seeing patients with SHL is increasing thanks to advances in imaging diagnosis. Recognition of SHL as an initial symptom of acoustic tumor is considered essential to detect small acoustic neuroma.     

Auditory brain-stem response and hearing threshold in cerebellopontine angle tumours

Summary The auditory brain-stem responses (ABR) in 19 patients with confirmed cerebellopontine angle tumours are evaluated in relation to the hearing threshold as obtained by pure-tone audiometry. ABR pathological alterations, in terms of either absence or presence of components, appear to relate to the suprathreshold stimulus intensity and to match the changes which can be observed in subjects with normal hearing, when stimulated at the equivalent suprathreshold intensity. Of the diagnostic indexes considered (I-V interval, IT₅, V), IT₅ and V could be evaluated in the largest patient population. They may be used in combination to enhance their sensitivity in retrocochlear lesion detection.     

Sudden hearing loss associated with piroxicam

Tinnitus has been reported with use of piroxicam (Feldene) a nonsteroidal anti-inflammatory drug. Two cases of temporary hearing loss have also been reported. To the best of our knowledge the patient reported herein represents the first case of permanent hearing loss and tinnitus associated with use of the drug.     

儿童突发性感音神经性聋发病特点分析

目的 :探讨儿童突发性感音神经性聋 (突发性聋 )的发病特点 ,以指导临床诊断与治疗。方法 :总结2 1例 14岁以下突发性聋患儿 (儿童组 )的临床表现及预后等 ,并与 6 7例成年突发性聋 (对照组 )进行对比分析。结果 :儿童组中 11例 (5 2 .4 % )查到可能的病因 ,其中腮腺炎 4例 (19% )、上呼吸道感染 3例 (14 .3% )、耳毒性药物中毒 2例 (9.5 % )、声损伤和代谢性脑病各 1例 ;对照组 19.4 %找到可疑的病因。入院时儿童组听力受损平均88.6dB ,对照组 80 .2dB ,两组差异有统计学意义 (P <0 .0 5 ) ;治疗后儿童组听力平均提高 14 .3dB ,对照组提高37.8dB ,两组差异有统计学意义 (P <0 .0 5 )。结论 :儿童突发性聋的特点多有明确病因 ,其中以病毒感染多见 ,其耳聋程度重 ,预后较成人差     

Sudden hearing loss: an update

Etiologic theories of idiopathic SHL include viral infection, autoimmune disease, vascular insult, and labyrinthine membrane rupture. A review of recent literature on sudden hearing loss indicates that scientific support for viral and autoimmune etiologic mechanisms is increasing. Recently studied treatment protocols include carbogen inhalation and steroid therapy. In patients with moderate hearing losses, oral steroids may be beneficial.