Paul A. Fagan

Facial nerve schwannoma: surgical excision versus conservative management.

Facial nerve schwannomas are slow-growing tumors that may involve any part of the facial nerve. When they present with moderate to total facial palsy, complete resection is clearly indicated. However, in cases with mild or no facial dysfunction, the best course of treatment is less obvious. A series of 22 patients with facial nerve schwannoma is presented, of whom 12 underwent definitive excision and 10 were managed more conservatively. The best postoperative facial function in the group who had tumor removal was a House-Brackmann grade III, while 8 of the conservatively treated group had normal facial function up to 10 years after presentation. As well, no significant tumor growth was noted on serial radiologic imaging of those being observed. Delaying surgical resection of facial nerve schwannomas may allow patients to retain normal facial function indefinitely.

A Histopathologic Review of Temporal Bone Exostoses and Osteomata

It is widely accepted that external auditory canal exostoses and osteomata are separate clinical entities that differ in their gross appearance. Disagreement still exists as to whether external auditory canal exostoses and osteomata should be considered similar or separate histopathologic entities. A chart review was performed of all patients who had external auditory canal exostoses or temporal bone osteomata excised from January 1991 to November 1994 at St. Vincents Hospital, Sydney. A histologic examination was undertaken with a blind study method of the patients whose pathological specimens were suitable for assessment. Eight exostoses and five osteomata were available for examination. The results of this study demonstrate that exostoses and osteomata of the external auditory canal cannot be reliably differentiated by routine histopathological examination.

Hearing Results following Modified Radical versus Canal-up Mastoidectomy

Modified radical mastoidectomy (MRM) provides relatively safe surgical access for the removal of chronic middle ear and mastoid disease and gives reproducible results. However, it has been suggested that hearing may not be as good as that after “intact canal wall mastoidectomy” (ICWM). This paper reviews 153 tertiary referrals suffering from extensive disease who underwent MRM and compares their hearing results with those obtained by other authors using ICWM and MRM and a variety of reconstructive techniques. In this study there were no dead ears and no significant changes in bone conduction despite prolonged drilling and extensive disease. Hearing results after MRM were found to be better after primary surgery than after revision and better in the presence of an intact stapes. No rigid prostheses were used at first-stage surgery. There were no significant differences found between hearing results obtained by MRM in this series and other published results of canal wall down mastoidectomy and ICWM, irrespective of the use of ossicular replacement prostheses.

Predictive factors of long-term facial nerve function after vestibular schwannoma surgery

Objective To assess predictive factors of long-term facial nerve function in a series of patients undergoing vestibular schwannoma surgery and to evaluate the reproducibility of the relevant parameters. Study Design Prospective. Setting Three tertiary referral neurotology units in two separate countries. Patients A total of 67 patients, with normal preoperative facial function and an anatomically intact facial nerve postoperatively, undergoing vestibular schwannoma surgery during a sequential 18-month period. Interventions Recording of intraoperative stimulus amplitudes (minimum intensity medial to the tumor after excision) and postoperative facial nerve function up to 2 years after surgery. Main Outcome Measures Long-term facial nerve function related to tumor size, early postoperative facial nerve function, and intraoperative electrophysiologic intensities. Results Multivariate logistic regression model identified tumor size and the minimum intensity required to provoke a stimulus threshold event medial to the tumor after excision as independent predictors of a favorable initial outcome. Immediate facial nerve function was the only independent predictor of long-term normal function. The sensitivity of this predictor was 95% (95% confidence interval [CI], 89–100%); specificity, 83% (95% CI, 62–100%); positive predictive accuracy, 96% (95% CI, 91–100%); and negative predictive accuracy, 77% (95% CI, 54–100%). Conclusion The combination of electrophysiologic intensities and tumor size are reproducible and better predictors of initial facial nerve function than any individual parameter, but long-term facial nerve function is more likely to have a better outcome if the nerve is left intact and a per-operative graft repair is not performed. The study suggests that although the best available predictor of overall long-term facial nerve outcome is the level of early postoperative function, this factor is not useful in surgical rehabilitation decision making.

Evolution of the Management of Hydrocephalus Associated with Acoustic Neuroma

The management of hydrocephalus in association with a cerebellopontine angle tumor is controversial. There is a widely held belief that initial therapy should always be directed toward treatment of hydrocephalus before definitive surgery. The potential problems of cerebrospinal fluid (CSF) shunting and drainage have led to an evolution in the management of hydrocephalus at St. Vincents Hospital. There is growing evidence that complete removal of cerebellopontine angle tumors will result in resolution of hydrocephalus without requiring other methods of CSF decompression. The authors present their experience of 14 patients with hydrocephalus found in a recent series of 104 consecutive cases of acoustic neuroma. This study has detected a significant correlation between hydrocephalus and increasing tumor size (P=.0234). The mean tumor size in this series was 3.8 cm. The series has also demonstrated that successful, safe, and complete tumor removal can be achieved without CSF drainage before surgery.

Drill-induced hearing loss in the nonoperated ear.

The reversible hearing loss in the nonoperated ear noted by patients after ear surgery remains unexplained. This study proposes that this hearing loss is caused by drill noise conducted to the nonoperated ear by vibrations of the intact skull. This noise exposure results in dysfunction of the outer hair cells, which may produce a temporary hearing loss. Estimations of outer hair cell function in the nonoperated ear were made by recording the change in amplitude of the distortion-product otoacoustic emissions before and during ear surgery. Reversible drill-related outer hair cell dysfunction was seen in 2 of 12 cases. The changes in outer hair cell function and their clinical implications are discussed.

The Outcome of Vestibular Nerve Section for Intractable Vertigo: The Patient's Point of View

To document the outcome of vestibular nerve section from the patients point of view we reviewed 102 patients who had undergone vestibular nerve section 1 to 10 years after operation. Only 3 patients had experienced further vertigo attacks: 2 of these were cured by a further, this time translabyrinthine vestibular nerve section; 1 patient developed multiple sclerosis. In contrast, about 50% of patients developed some subjective problem with balance while standing or walking; in 15% it was present all the time and of moderate severity. Despite this, over 85% of patients reported that they felt much better or back to normal after the operation and were satisfied with the outcome. The development and application of objective preoperative measures of vestibular and, in particular, vestibulospinal function might improve patient selection for vestibular nerve section and thus reduce the number of dissatisfied patients.

Large vestibular aqueduct syndrome and stapes fixation

An abnormally large vestibular aqueduct has a well recognized association with inner ear anomalies and it has been assumed previously to be a variant of a Mondini type of deformity (Shuknecht, 1980; Emmett, 1985). The sole radiological finding in some patients with progressive sensorineural loss has been a large vestibular aqueduct (Valvassori and Clemis, 1978; Valvassori, 1983), which is now accepted as a separate clinical entity, i.e. the large vestibular aqueduct syndrome (LVAS). A case is presented which is believed to be the first reported with unilateral LVAS and stapes fixation and also the first stapes gusher described in association with LVAS.

Hearing preservation in acoustic neuroma surgery: A continuing study

Hearing preservation in acoustic neuroma surgery is possible in a limited number of cases. Although there have been many articles published about hearing preservation, there have been few studies of long‐term hearing results, nor is it known if there is an increased rate of tumor recurrence when hearing preservation is attempted. Twenty‐two patients who underwent a hearing preservation procedure via the retrosigmoid approach were selected from 80 consecutive patients with cerebellopontine angle tumors operated on from February 1984 to November 1987. Useful hearing was retained in 11 cases as reported in a previously published study. Seven patients continue to have useful hearing after 3 to 5 years; 3 have shown a gradual but slight decline. There has been no tumor recurrence in these patients, but 2 patients, operated on early in the series and who had lost hearing, had recurrent tumor.

Unusual lesions of the internal auditory canal

Acoustic neuromata (AN) account for nearly 90 per cent of internal auditory canal (IAC) and cerebello-pontine angle (CPA) tumours. The second most common tumour is meningioma. Rare lesions include primary cholesteatoma, facial neuroma, lipoma, angioma and various cysts. Two cases of IAC tumour are presented, one of hamartoma in which smooth muscle was prominent and the other of lymphangioma. Of interest are the specific clinical and radiological features associated with these lesions.