Experiences with radically operated acoustic tumours

Acoustic neuroma: a review of 392 cases

A retrospective study was made of all operations for acoustic tumour over a 40-year period. A total of 392 cases are reported. Trends over time and with the size of the tumour are reported. In the current decade all but two tumours were completely resected, the mortality rate was 1.4%, 94% of patients had a good or excellent result, the facial nerve was preserved in 64% of cases (90% of these with acceptable function) and the cochlear nerve in 13.5% (some with hearing). There is a striking dependence on the size of the tumour of the likely outcome of operation.

Acoustic neuroma surgery: results of translabyrinthine tumour removal in 300 patients. Discussion of choice of approach in relation to overall results and possibility of hearing preservation

The results from the Danish model of acoustic neuroma surgery are presented. In the period from 1976 to 1985, 300 patients with acoustic neuromas were operated upon using the translabyrinthine procedure. Only one small intrameatal tumour was encountered; 96 tumours were medium sized and 203 were larger than 25 mm. Of these 118 measured more than 40 mm. Mortality rate was 2%, CSF leaks occurred in 11%, and had to be closed surgically in 5%. Facial nerve function was postoperatively normal in 66%, slightly reduced in 17%, moderately reduced in 8% and abolished in 9%. Reconstruction, most often as a XII-VII anastomosis, was performed in only 6% of the patients. Cerebellar symptoms, which occurred in 45% preoperatively were present in only 7% after surgery. The preoperative hearing in both the tumour and non-tumour ear was analysed in 72 patients with tumours smaller than 2 cm. In the tumour ear, only four patients had a PTA of 0-20 dB and SDS of 81-100%; eight patients had a PTA of 0-40 dB and SDS of 61-100%; 14 had a PTA of 0-50 dB and SDS of 51-100%. This means that only a maximum of 5% of the patients, using the broadest criteria, could be candidates for hearing-conserving surgery. In all these patients the contralateral ear had hearing within normal limits (PTA 0-20 dB and SDS 95-100%). Since preservation of hearing would be achieved in only half of those subjected to suboccipital removal and since the hearing retained in patients with successful operations generally is poorer than the preoperative level, the number of patients obtaining serviceable hearing is so modest that preservation of hearing cannot be considered a valid argument in favour of suboccipital tumour removal. From a statistical point of view the risk of losing hearing in the opposite ear after tumour removal is negligible. The general morbidity after suboccipital surgery is higher than after translabyrinthine surgery, and hearing loss must be listed low among the other sequelae after tumour removal.

Surgical management of acoustic neuromas during the last five years. Part I

A consecutive series of 94 patients with acoustic neuromas, who were treated in the years 1980-1984, was reviewed. Hearing loss was the most common presenting symptom. During 1980-1984, all acoustic neuromas were treated surgically; 93 cases had a total excision and only one case had a subtotal excision. Mortality and morbidity were low and patients who had a fair to poor outcome rating had large tumors. Overall, cranial nerve VII was preserved in 64.1% of cases, while cranial nerves VII and VIII were anatomically preserved in 27% of cases.

Surgical management of acoustic neuromas during the last five years. Part II: Results for facial and cochlear nerve function

Postoperative facial and cochlear nerve function in 83 consecutive patients with acoustic neuromas, who were undergoing their initial surgical procedure during 1980-1984, have been examined. The facial nerve was preserved in anatomic continuity in 71% of cases. Various nerve grafting procedures were used when the facial nerve was divided; the most common of these was a faciohypoglossal anastomosis, which was performed in 20 cases. The facial and cochlear nerves were anatomically preserved in 30.1% of all patients having their initial surgical procedure. Good speech discrimination was preserved in four patients, whereas more crude hearing was preserved in six other patients.

Results of translabyrinthine removal of 300 acoustic neuromas related to tumour size

The results from the Danish model of acoustic neuroma surgery are presented. In the period from 1976 to 1985, 300 patients with acoustic neuromas were operated upon using the translabyrinthine procedure. There were one small intrameatal tumour; 96 medium-sized tumours with an extrameatal diameter up to 25 mm; 85 large tumours, measuring 26-40 mm, and 118 very large tumours with a diameter exceeding 40 mm. The mortality rate was 2%, and CSF leak occurred in 11%, persisting for more than 2 weeks in 5% of the patients in whom the fistula had to be closed operatively. Facial nerve function was completely normal in 66%, slightly reduced in 17%, moderately reduced in 8% and abolished in 9%. The facial nerve was anatomically preserved in 95% of the patients. Reconstruction of the facial nerve, most often an XII-VII anastomosis, was performed in only 6% of the patients. Cerebellar symptoms, occurring in 45% preoperatively, were demonstrated in only 7% postoperatively. We find that a standardization of the measurement of tumor size and of the assessment of sequelae changes is urgently needed.

Is preservation of hearing in acoustic neuroma worthwhile?

In a series of 300 translabyrinthine removals of acoustic neuromas, comprising almost all tumours operated on in Denmark during a period of 10 years, the preoperative hearing in the tumour ear and in the contralateral ear was analysed in 72 patients with tumours smaller than 2 cm in extrameatal diameter. These patients constitute likely candidates for a hearing preserving operation via the suboccipital approach. In the tumour ear in 4 patients there was a pure-tone average (PTA) of 0-20 dB and a discrimination score (DS) of 81-100%. Applying this criterion to the whole series, 1% of the patients would be candidates for a hearing preserving procedure. Changing the criterion to a PTA of 0-40 dB and a DS of 61-100%, the number of candidates would increase to 8 patients (3%), and with a PTA of 0-50 dB and a DS of 51-100% 14 candidates (5%) would have been found. In all of these patients, contralateral hearing was normal (SRT 0-20 dB, DS 95-100%). Since preservation of hearing would be achieved in only half of those subjected to suboccipital removal and since the hearing retained in patients with successful operations is generally poorer than the preoperative level, the number of patients obtaining serviceable hearing is so modest that preservation of hearing cannot be considered an argument in favour of suboccipital tumour removal. It should be borne in mind that contralateral hearing is normal in these patients and that, according to most reports, the mortality rate is higher and paralysis of the facial nerve more frequent with the suboccipital approach than with the translabyrinthine procedure.

Does intravascular coagulation contribute to the operative mortality for large acoustic neuromas?

Three cases of abnormal bleeding during suboccipital excision of large acoustic neuroma are reported. The possible role of limited operative intravascular coagulation is discussed.

Epidemiology of acoustic neuromas

In Denmark one surgical team, during the last 7 years, has performed about 80 per cent of all acoustic neuroma surgery. Because of this centralization, in such a limited population as that of Denmark, we have attempted to make a epidemiological survey of all diagnosed tumours in the period from 1976 to 1983. Systematic and prospective records were made by the authors of all patients with translabyrinthine operations, and data on patients with suboccipital operations were collected retrospectively from the six neurosurgical departments in Denmark. The average annual incidence was 8 tumours per million inhabitants, with the highest incidence of approximately 13 tumours per million occurring in Copenhagen County. The incidence reported in previously published autopsy series is 800-900 times higher and the following may serve as an explanation for this enormous difference: Autopsy series are in all probability based on highly selected cases; they are predominantly based on elderly people and the incidence is not directly applicable to the population at large. Several of the silent tumours from the autopsy series were located in the cochlea or in the labyrinth and not in the internal ear canal. The conclusion from our study is that both the knowledge and data available at present are insufficient to serve as a basis for an actual calculation of incidence and prevalence of acoustic neuromas.(ABSTRACT TRUNCATED AT 250 WORDS)

The price of preservation of hearing in acoustic neuroma surgery

Translabyrinthine surgery for acoustic neuroma was introduced in Denmark in 1976, and the results of the first 100 operations are presented. Two deaths occurred, unrelated to the translabyrinthine surgery. Postoperatively, 75% of the patients had normal facial function, while function was reduced in 15% and abolished in 10%. The series represents 85% of all acoustic neuromas operated in Denmark, with 30 new neuromas being diagnosed each year, derived from a population of 5.1 million. The overall postoperative results are compared with the available results from suboccipital removals of acoustic neuromas, and are clearly in favor of the translabyrinthine approach. It is concluded that centralization of acoustic neuroma surgery is necessary, that all acoustic neuromas regardless of size can be removed by the translabyrinthine approach and that the discussion about the hypothetical preservation of hearing by applying the suboccipital approach is being made without solid grounds. To adduce the theoretical chance of preserving hearing in a very small percentage of patients as an argument in favor of the suboccipital approach appears quite irrelevant, and the price of attempting this with the suboccipital approach is too high.

Translabyrinthine and transtentorial removal of acoustic nerve tumors. Results in 150 cases

The translabyrinthine route or an extension of it was used to remove 150 acoustic nerve tumors. The mortality was 2% and the morbidity low. Preservation of the facial nerve was achieved in 100% of the small and 80% of the medium-sized tumors, but in only 20% of the large growths. The complications encountered are discussed.

Total removal of acoustic neurinomas

The authors analyze the results of total removal of acoustic neurinomas in 120 patients operated on between January, 1967, and January, 1976. The facial nerve was preserved after surgery in 65 patients (54.2%). The use of microsurgical techniques in the last 3 years of study permitted preservation of the seventh nerve in 26 of 35 operated patients (74.3%). Of 103 patients examined postoperatively, 96 retained their full or partial capacity for work (93.2%). Ten patients (8.3%) died after surgery. In the last 3 years, 35 patients were operated on without a single death.

Facial nerve function after suboccipital removal of acoustic neurinoma

The recovery of facial nerve function after suboccipital removal of 91 acoustic neurinomas is presented. The results after anatomical preservation of the nerve (60 cases), direct anastomosis of the nerve (7 cases), nerve grafting (16 cases), and facial hypoglossal anastomosis (8 cases) are presented after a follow-up period of 31.2 months. A simplified classification was used to describe motor function. The results are compared to those in the literature.