Preservation of hearing in large acoustic neurinomas following removal via suboccipito-lateral approach

A consecutive series of 61 patients with pre-operative hearing underwent surgical removal of a large acoustic neurinoma via the lateral suboccipital approach between 1984 and 1996. Brain-stem auditory evoked potentials (BAEP) were present in all cases before surgery and all patients underwent intra-operative monitoring of BAEP. The average tumour size including the portion within the meatus acusticus internus was 30, 5 mm (range 20 mm-49 mm). Complete tumour removal was achieved in all but three cases. In 43.1% of patients with complete tumour removal hearing was preserved initially after surgery. Delayed postoperative hearing loss was observed in 11 patients and hearing recovery in 2 patients leading to 27.5% definite hearing preservation. Hearing preservation was achieved in 37% of cases with tumour size between 20 mm-29 mm and in 23.5% of case with tumour size larger than 30 mm. These results indicate that even in large neurinoms hearing preservation should be attempted in all patients with documented pre-operative hearing and BAEP.     

Hearing preservation in acoustic tumor surgery: results and prognostic factors

A retrospective study was conducted to assess the hearing results in patients who underwent acoustic neuroma removal via the middle fossa approach. A statistical correlation of results with preoperative clinical and audiological data determined if any prognostic indicators could be associated with successful hearing preservation. Of 93 patients included in the study, useful hearing was preserved in 54 (58%), and hearing was preserved near preoperative levels in 42 (45%). The potential for hearing preservation appeared to be inversely related to the size of the acoustic tumor, with hearing preserved in 39 (60%) of 65 patients with tumors less than or equal to 0.5 cm extension into the cerebellopontine angle. Preoperative hearing levels and electronystagmography seemed to have no prognostic value. However, auditory brainstem response showed that a wave V latency of less than 6.8 msec was associated with an increased chance of hearing preservation, and the presence of vertigo as a preoperative complaint appeared to be a good prognostic indicator of successful hearing preservation.     

Replacement by homologous recombination of the minK gene with lacZ reveals restriction of minK expression to the mouse cardiac conduction system

Surgical approaches to the inner ear with hearing preservation have valuable implications for neurotologic surgery. In a previous study in guinea pigs, we demonstrated that click-evoked auditory brain stem responses (ABRs) were preserved after transection and plugging of 1 or more semicircular canals but were lost after entering the vestibule (Smouha EE, et al. Otolaryngol Head Neck Surg 1996; 114:777-784). A limitation of that study was that click-evoked ABR might not represent the function of the entire cochlea. In this study we used tone-burst ABR to determine thresholds across a broad range of frequencies (2 to 24 kHz) before and after surgical entry into the labyrinth at the lateral semicircular canal, ampulla, and vestibule. Serial measurements were made, and a sham surgery group was used as a control. The results obtained with tone-burst ABR generally agreed with those previously obtained with click stimuli. Toneburst ABR thresholds were similar across most frequencies tested. Transection of the lateral semicircular canal resulted in preservation of ABR thresholds. Ampullectomy had a variable effect on ABR thresholds. Vestibulotomy usually resulted in substantial hearing loss. We conclude that hearing can be preserved across a range of frequencies after selective surgery of the inner ear. Surgical entry into the membranous labyrinth near the vestibule is the critical factor contributing to hearing loss after partial labyrinthectomy.     

Quality of hearing preservation in acoustic neuroma surgery

OBJECTIVE: This study aimed to investigate the factors affecting the quality of postoperative hearing in acoustic neuroma. STUDY DESIGN: The study was designed as a retrospective case review. SETTING: The study was performed at the Department of Otolaryngology, School of Medicine, Keio University, Tokyo, Japan. PATIENTS: The subjects were 94 patients with unilateral acoustic neuroma. INTERVENTION: Hearing preservation surgery was performed in the subjects via the extended cranial fossa approach or the middle cranial fossa approach. MAIN OUTCOME MEASURES: The outcome measures included patient's age and gender, hearing level, speech discrimination score, tumor size, and surgical approach. The relationship between the qualities of preoperative and postoperative hearing and the long-term prognosis of preserved hearing also was investigated. RESULTS: In 94 subjects, there were 47 patients whose hearing was preserved (HP group) and 47 patients whose hearing was not preserved (non-HP group). Overall, hearing preservation rate was 50%. There were no significant differences in age, gender, and tumor size between the two groups. The hearing preservation rate was significantly higher in patients with an intracanalicular tumor than that with a larger tumor. The better the preoperative quality of hearing was, the higher the postoperative one. Although the preserved hearing deteriorated after surgery in 4 patients, no significant hearing deterioration was observed in the other 43 patients. CONCLUSIONS: The results of this study indicated that the diagnosis for acoustic neuroma in the early stage with serviceable hearing is the most important to improve the quality of postoperative hearing.     

Prognostic factors for hearing preservation following observation-only versus stereotactic irradiation (STI) in patients with acoustic neuroma

Prognostic factors for hearing preservation following observation-only versus STI were compared in patients with acoustic neuroma. There were 48 patients with acoustic neuroma treated by fractionated STI. Between 1991 and 1997, patients were given 36 Gy in 20 fractions over 5 weeks (36 Gy/20 Fr/5 wks) to 44 Gy/22 Fr/6 wks followed by a 4 Gy boost. A linear accelerator was used for irradiation. Twenty-three patients with acoustic neuroma who were followed without any treatment (observation-only group) were selected as matched controls. The largest hearing loss was observed at the frequency of 2 kHz in the observation-only group and at 1-2 kHz in the STI group. Hearing loss at 1 kHz was more frequent in the STI group (p < 0.01). There were no significant prognostic factors which predicted hearing preservation in the observation-only group. Stereotactic irradiation has been suggested to damage to cochlear nerve function in patients whose cochlear nerve had been impaired already. Tumor control rate of STI appeared to be as good as single fraction radiosurgery rates in the literature and better than in the observation-only group. Hearing preservation rate in the STI group was as good as in the observation-only group and appeared to be better than single fraction radiosurgery. In conclusion, because there were no factors predictive of hearing preservation in the observation-only group, it is difficult to select patients for observation only. Fractionated STI is potentially the treatment of choice, resulting in the same hearing preservation rate as achieved with observation only, although longer follow-up periods are needed.     

Different aspects of hearing preservation in surgery of vestibular schwannoma in women and men

Pre-operative and postoperative auditory function was reviewed retrospectively in 98 patients with vestibular schwannomas. According to their hormonal status, women were categorized as "premenopausal" and "postmenopausal". Before surgery, 48% of the women (65% premenopausal) and 16% of the men presented with sudden hearing loss. The degree of auditory function before operation was similar for women and men. Preservation of pre-operative hearing was possible for 41% of the women (21% premenopausal) and 59% of the men. Further details of the surgery and the results of histopathological examination were also compared for women and men. Our results support substantial evidence that hearing preservation after surgery of vestibular schwannoma is easier to accomplish for men than for women. The finding of significantly more sudden hearing loss in premenopausal women may suggest a hormonal influence on tumour growth, which may also be partially responsible for the difference in hearing prognosis between women and men.     

Treatment modalities for hypertensive patients with intracranial pathology: options and risks

Several reliable surgical procedures aimed to control the vertigo associated with Meniere's disease exist. Vestibular preservation and ablative procedures are available with the latter divided between hearing preservation and destructive operations. Factors to consider prior to choosing a surgical option include the age, health, and employment status of the patient; the degree of hearing loss in the involved ear; and the status of the contralateral ear.     

Intracochlear placement of cochlear implant electrodes in soft surgery technique

It is commonly accepted that the intracochlear placement of the cochlear implant electrode is potentially damaging to the hearing rests which may exist. Consequently, cochlear implants have been recommended for totally deaf ears only. The question has been raised whether or not it is possible to preserve residual hearing during intracochlear implantation through extremely careful surgical techniques. Experience has shown, that the cochleotomy of the scala tympani anterior to the round window niche, careful preservation of the fibrine endost layer and the use of Healon are amongst the surgical procedures described which may assist in retaining the rest function of the inner ear. These observations which are discussed in detail suggest that the experienced surgeon can effect preservation of residual hearing for patients who cannot derive significant benefits from conventional acoustic amplifiers.     

Laser applications in inner ear surgery

Argon and carbon dioxide lasers can cause heat shrinkage of the membranous labyrinth without injury to hearing. The argon laser can penetrate the membranous labyrinth and cause destruction of targeted vestibula special sensory epithelium also without injury to hearing. Consequently, these lasers have been used successfully in two treatment techniques for benign paroxysmal positional vertigo, which are discussed in detail. The early techniques for laser assisted resection of the pars superior portion of the inner ear with hearing preservation are discussed.     

Topical oxatomide: an alternative approach for the treatment of vulvar lichen sclerosus

We report a case of bilateral congenital cholesteatoma in a 6-year-old boy. Cholesteatoma was present in both ears around the tympanic isthmus (the only open passage from the tympanic cavity to the attic), extending to behind the horizontal portion of the facial nerve. This patient underwent a total of three canal wall up operations on each side to remove the cholesteatoma completely and improve hearing. This case fulfills the criteria proposed by Derlacki and Clemis in 1965. Bilateral congenital cholesteatoma is a rare condition, but the incidence of congenital cholesteatoma in children has increased recently for the following reasons: Reassessment of the criteria, the introduction of computed tomography, and increased awareness of congenital cholesteatoma. When operating on patients with bilateral cholesteatoma, the best method for preservation of hearing should be chosen. We discuss these problems in the present report.     

Preservation of cranial nerve function after treatment of acoustic neurinomas with fractionated stereotactic radiotherapy. Preliminary observations in 26 patients

Twenty-seven acoustic tumors in 26 patients were treated with multiple fractionated linear-accelerator-based stereotactic radiotherapy (SRT). All patients with intact pretreatment facial nerve function with either small or large tumor volumes have thus far experienced no treatment-related facial neuropathy, including 9 patients with a mean follow-up of 22.4 +/- 1.6 months. The incidence of evaluable trigeminal neuropathy was 13%, and in 5 of 7 patients with serviceable pretreatment hearing, audiometry was unchanged in the immediate posttreatment period. Longer follow-up will be necessary to evaluate hearing preservation after SRT. Tumor response with central necrosis was seen in all assessable patients. SRT can be performed for cerebellopontine angle tumors with accuracy and reproducibility. It achieves a biological response similar to single fraction radiosurgery and may lower the incidence of facial and trigeminal neuropathies.     

Results of three different stapedectomy techniques: a comparative study]

We perform a comparative study on the results obtained through three stapedectomy techniques. The hearing gain was evaluated in 107 ears with total footplate removal, Shea prosthesis and connective tissue graft, in 81 ears with particular footplate removal, the same prosthesis, and no tissue graft, and in 66 ears with stapedectomy. The differences between the three groups in the air-bone gap closure or postoperative complications were not statistically significant. We conclude that results depend more on the surgeon than on the technique.     

Bilateral renal cell carcinoma in a horseshoe kidney: preoperative assessment with MRI and digital subtraction angiography

Renal cell carcinoma in a horseshoe kidney is an unusual entity. To our knowledge, only 123 cases have been published to date. We report the first bilateral case of two clear-cell carcinomas in an asymmetrically fused kidney. Optimum preservation of renal function after radical tumor removal requires accurate preoperative imaging. Since the vascular supply in fusion anomalies is extremely variable, angiography is mandatory. Magnetic resonance imaging was most suitable to predict the tumor extent and localization, because it simultaneously gave the most comprehensive anatomical overview of the malformation.     

Osteoid osteoma of the petrous bone

We present a case of osteoid osteoma of the petrous bone presenting with progressive sensorineural hearing loss. CT showed a dense homogeneous mass at the promontory surrounded by a thin bony border. On MRI this lesion gave intermediate signal intensity on T1- and T2-weighted spin-echo images and enhanced intensely with gadolinium. Surgical removal and pathological study proved the diagnosis.     

Preservation of the anterior urethral ligamentous attachments in maintaining post-prostatectomy urinary continence: a comparative study

PURPOSE: The impact was determined on post-prostatectomy urinary incontinence of a technique preserving the anterior attachments of the proximal urethra to the posterior pubis by comparison to the results of other surgical methods. MATERIALS AND METHODS: Urinary continence in 51 patients undergoing preservation of the anterior urethral attachments was compared to that of 70 patients undergoing an anatomical prostatectomy with resection of the bladder neck, 55 patients with preservation of the bladder neck and 14 patients undergoing a dorsal vein gathering procedure. Comparisons were made for rate of total continence, time to return of continence, incidence of extra organ disease and operative blood loss. RESULTS: Total continence at 1 year was 84.3%, 89.1%, 85.7% and 100% respectively. Immediate total continence after catheter removal was seen in 25.5% after preservation of the anterior urethral attachments, 80.4% at 3 months compared to 41.4%, 50.9% and 50% at 3 months for anatomical prostatectomy with bladder neck resection, preservation and dorsal vein gathering. Clinical staging with the incidence of specimen confined disease was similar in all groups. Mean operative blood loss was 1,031 ml. for those patients undergoing anatomical prostatectomy compared to 681 ml. for those with preservation of the anterior urethral attachments. CONCLUSIONS: Preservation of the anterior urethral attachments results in improved urinary continence and lower operative blood loss without an increase in positive surgical margins.     

Space-occupying lesions as a cause of tarsal tunnel syndrome

In diagnosing the etiology of tarsal tunnel syndrome, the practitioner must be aware of space-occupying lesions as a possibility. These masses, rarely found beneath the laciniate ligament, can occur. Satisfying results have occurred after removal of these lesions. Careful dissection will assure preservation of the nerve and prevent sensory or motor loss.     

Assessment of hepatic viability during cold ischemic preservation

A reliable and easy method for assessing the viability of a cold ischemia-preserved donor liver prior to transplantation into the recepient is needed. Based on an earlier study, we hypothesized that liver free fatty acid (FFA) leakage into the preservation fluid may be a useful, atraumatic indicator of irreversible ischemic injury. The aim of the present study was to determine the time course and magnitude of liver FFA release into the preservation solution and its correlation with the duration of cold ischemic preservation compatible with survival after transplantation. Rat livers (n = 48) were flushed and preserved with University of Wisconsin (UW) solution at 4 degrees C for 0, 12, 24, and 48 h. Thereafter, half of the livers were analyzed for preservation fluid FFA (gas-liquid chromatography) and protein. The other half were perfused with Krebs-Henseleit (KH) solution at 37 degrees C for 1 h. Bile secretion and liver enzyme release (SGOT, SGPT, and LDH) were measured in addition to perfusate FFA and protein. Total FFA in the preservation fluid was 24 micrograms/g wet tissue after 12 h; it increased sharply 2.6-fold after 24 h and 3.7-fold after 48 h of preservation. Bile production was normal after 12 h of preservation but fell by 20% and 54% after 24 h and 48 h, respectively. LDH release rose from a value of 20 U/l at 0 time to 120 U/l and 260 U/l after 24 h and 48 h of preservation. These results suggest that liver viability declines sharply between 12 and 24 h of cold ischemic preservation, which corresponds with a sharp decrease in the 1-week survival from 100% to 33% after 12 h and 24 h, respectively, of cold ischemic preservation. We conclude that measuring FFA and LDH in the preservation solution of donor livers may be a useful means of assessing the quality of the cold-preserved liver before insertion into the recipient. We also speculate that a "threshold" FFA level in the UW preservation fluid indicating irreversible damage may be in the order of 35 micrograms total FFA/g liver. Studies on the clinical applicability of our findings are currently under way.     

Fibrous dysplasia of the temporal bone: reversal of sensorineural hearing loss after decompression of the internal auditory canal

When fibrous dysplasia affects the temporal bone, it most often presents with conductive hearing loss attributable to stenosis of the external auditory canal. Sensorineural hearing loss has usually been attributed to involvement of the otic capsule. We present a patient with bilateral fibrous dysplasia of the temporal bones who complained of unilateral hearing loss, facial tingling, and facial twitching. The audiogram showed severe sensorineural hearing loss. The hearing markedly improved and facial twitching and tingling ceased after decompression of the internal auditory canal via a middle fossa approach. This is the only case of which we are aware showing reversal of sensorineural hearing loss caused by fibrous dysplasia.     

Early result comparison following mitral valve replacement with partial or entire subvalvular structure preservation

21 patients after mitral valve replacement with partial subvalvular structure preservation and 20 patients with entire subvalvular structure preservation were compared with 26 patients after mitral valve replacement with entire subvalvular structure excision. We found that patients after mitral valve replacement with partial or entire subvalvular structure preservation had a more uneventful postoperative course with less inotropic therapy and more decreased left atrial dimension when compared to those with conventional mitral valve replacement. But the patients after mitral valve replacement with entire mitral structure preservation had more decreased left ventricular dimension and short hospital stay when compared to those of the other two groups. The authors suggest that mitral subvalvular structure should be preserved, and we especially recommend the procedure of intravalvular implantation of mitral prosthesis with entire mitral subvalvular structure preservation.     

Large-scale purification and preliminary x-ray diffraction studies of human aspartylglucosaminidase

Selective vestibular neurectomy is an effective treatment for intractable vertigo of peripheral vestibular origin when preservation of hearing is a goal. The retrolabyrinthine and retrosigmoid-intracanalicular approaches have been used predominantly at our institutions over the last 10 years. The results and complications of these two techniques were compared. No significant differences were found between hearing results in these two patient groups. The retrosigmoid-internal auditory can approach yielded better control of recurrent episodic vertigo, as well as superior ablation of postoperative ice-water caloric responses (p < 0.05). Surgical complications, including the incidence of cerebrospinal fluid leakage (greater in retrolabyrinthine approach) and postoperative headache (more prevalent in retrosigmoid approach), were also analyzed. To further evaluate the results of this study, data were reanalyzed and compared with previously published reports of selective vestibular nerve section.