Preservation of hearing in bilateral acoustic neurinomas by deliberate partial resection.

With the aim of preserving hearing, 20 acoustic neurinomas in 17 patients with neurofibromatosis 2 were intentionally submitted to an incomplete (80%) tumour removal. In 12 cases this was an operation on the last hearing ear with total deafness of the contralateral ear. If an auditus existed in both ears the better hearing ear was selected for the primary intervention. Early audiological controls evidenced residual hearing in 19 of the 20 cases operated on by the enlarged middle fossa approach, which was utilized inspite of the tumour diameters being between 1 and 6 cm in the cerebello-pontine angle. The oncologic and functional follow-up over 1 to 7 years showed different patterns of slow progression of hearing loss and of persistent auditory function over 2 to 7 years. Facial nerve function was excellent in 16 of the 18 controlled cases. Continued CT or MRT imaging revealed no signaling in 2 cases, constant tumour sizes in 10 cases and slow progression in 3 cases. With regard to the importance of an auditory communication in the younger adult, the described treatment modality appears to be the first choice method.

[Transcranial magnetic stimulation of the facial nerve in patients with acoustic neuroma]. / Transkranielle Magnetstimulation des Fazialisnerven bei Patienten mit Akustikusneurinom.

Magnetic stimulation of the human facial nerve was used in 30 patients with small or medium-sized acoustic neurinomas pre-operatively. Needle-EMG revealed symmetrical aspect in the orbicularis oris muscle on the affected and on the contralateral side. The latencies in the extracranial part of the facial nerve after supramaximal electric stimulation in the area of the stylomastoid foramen and the latencies after temporo-occipital, transcranial magnetic stimulation were measured. A comparison of the data showed a significant increase in the temporal conduction time (difference between latencies after transcranial magnetic stimulation and electrical mastoid stimulation) between the healthy and the affected side in most cases. This study revealed tendencies between prolongation of the latencies and the tumour size. No correlations were obtained to audiological or intra-operative findings.

New markers for the neurofibromatosis-2 region generated by microdissection of chromosome 22.

To identify new DNA markers around the neurofibromatosis-2 gene on human chromosome 22, the critical region (22q12-q13.1) was microdissected and microcloned from GTG-banded metaphase chromosomes. Eighteen thousand recombinant clones were obtained. Twenty-seven of 55 clones tested (50%) detected single-copy DNA sequences. Nine of nine clones analyzed in detail were found to map to chromosome 22. Interestingly one clone (EAN04) is part of the leukemia inhibitory factor gene which has previously been mapped to 22q11.2-q13.1. Four clones (EAN01, EAN47, EAN57, and EAN68) detect DNA polymorphisms. These probes were used to compare constitutional and tumor genotypes of 41 patients with acoustic neurinoma. Loss of constitutional heterozygosity was identified in 17 of 31 informative cases (55%). From our data we conclude that the microdissection library is a valuable resource for physical and genetic mapping studies in neurofibromatosis-2.

Extended middle cranial fossa approach for acoustic neuroma surgery.

The enlarged middle cranial fossa approach was used for removal of acoustic neuromas in 209 cases. Complete tumor removal was accomplished in 96% of cases. Hearing was preserved in 51% of cases, with better results in smaller tumors. Our experience with the enlarged middle fossa approach has led us to discard the translabyrinthine approach for removal of acoustic neuromas.

Topographical anatomy of the internal auditory canal. Implications for functional surgery in the cerebello-pontine angle.

For exposure of the cerebello-pontine angle by an enlarged middle-fossa approach without destruction of the inner ear, bone removal anterior and posterior to the internal auditory meatus (c.a.i.) can be performed with orientation at landmarks. Based on the experience of more than 300 interventions and documented by a series of 10 temporal bone micro-dissections, rules have been established for reliable localization of the following structures: geniculate ganglion, Fallopian canal, vertical crest at the fundus of the c.a.i., basal coil of the cochlea, and ampulla of the superior semicircular canal. The surgical technique has enabled the authors to remove acoustic neurinomas of up to 3.5 cm with preservation of hearing in 51%.

Posture and central compensation after acoustic neurinoma surgery.

After acoustic neurinoma surgery via the enlarged middle cranial fossa approach the patients usually benefit from a good prognosis of the vestibular compensation, almost independent of the size of the tumour and of the patient's age, if the central vestibular pathways were not injured. Only 8% of the patients showed a reduced vestibular compensation. The success and gradation of the vestibular compensation in diseases with a permanent labyrinthine loss, even though after acoustic neurinoma surgery, can easily be classified by the so-called vestibular-index.

[Diagnostic and treatment of lesions of the facial nerve after fractures of the temporal bone]. / Diagnostic et traitment des lésions du nerf facial après fractures du rocher.

The authors review functional late results of 47 cases of facial palsies due to otobasal fracture by considering the clinical and electrophysiological test results, seen between 1983 and 1988. There were 36 longitudinal, 5 transversal and 6 combined temporal bone fractures. 5 patients suffered from a bilateral facial paralysis. In all cases, an electrodiagnostic examination was carried out in order to determine the pronosis and to indicate a surgical exploration. The electrodiagnostic consisted in electromyographie (EMG) and electroneuromyographie (ENoG). 36 patients got a medical treatment and 6 patients were treated by surgery. All facial nerve paralyses (n = 28), that were incomplete according to the clinical examination as well as the electrophysiological tests, received a medical treatment which lead to good functional late results without exception. 19 facial nerve paralyses seemed to be complete in clinical examination, but in 11 cases electrodiagnostic tests revealed a residual volontary electrical activity. This indicated a conservative therapy with 7 good (66%) and 4 (33%) fair results. So, no poor result had been found in this group. In the other 8 cases, 4 of which had a delayed onset of the paralysis, no electrocal activity could be proved. 4 patients were treated by surgery, and in 2 cases a complete facial nerve transection was found. The reconstruction of the facial nerve led to 1 good and to 1 satisfactory result. In the other 2 cases, the decompression lead to 1 good and to 1 poor late result. In these 4 cases the facial nerve had been completely decompressed, in a combined transmastoidal and enlarged transtemporal middle fossa approach.(ABSTRACT TRUNCATED AT 250 WORDS)

Transtemporal planned partial resection of bilateral acoustic neurinomas.

In an attempt to overcome the complete auditory deprivation of young patients with bilateral acoustic nerve schwannomas (Morbus v. Recklinghausen) a planned partial resection of the tumour was carried out in 11 hearing ears. The cerebello-pontine angle was exposed by the enlarged middle fossa approach (Wigand et al., HNO 1985). A strip of tumour was left in contiguity to the facial and cochlear nerves. Hearing was initially preserved in all cases. Four of them, however, developed total deafness after 3-39 months. Recurrent tumour growth was checked by CT scans. During the observation time one resting tumour became invisible, five remained unchanged. Two grew larger. Three cases dropped out of the follow-up. With regard to the high value of preserved auditory function during the first decades of life the planned partial resection may be considered preferable for cases of bilateral acoustic neuromas.

[Gastric microhemorrhage and acetylsalicylic acid. Prevention using prostaglandin E2]. / Gastrale Mikroblutung und Acetylsalicylsäure. Prophylaxe durch Prostaglandin E2.

The possible prophylactic effect of prostaglandin E2 (PGE2) pretreatment against gastric microbleedings caused by acetylsalicylic acid was investigated in six healthy volunteers. Gastric microbleeding rate was determined by the gastric tube technique of Fisher and Hunt, at first without any medication. The test was repeated after a two-day intake of acetylsalicylic acid (four times 0.5 g/d) and after two days of the same dose, 15 minutes after the administration of PGE2 (four times 0.5 mg/d). Between the two treatment periods, their sequence randomized, there was a treatment-free pause of at least eight days. Basic gastric microbleeding rate was 0.42 +/- 0.10 ml/d (means +/- Smeans). After administration of acetylsalicylic acid this rose highly significantly elevenfold (4.59 +/- 1.64 ml/d). Prophylactic administration of PGE2 prevented this rise (0.24; 0.04-2.55 ml/d) (median; 10th-90th percentile). There were no side effects to the administration of PGE2.