Biological levels of aluminium after use of aluminium-containing bone cement in post-otoneurosurgery.

Use aluminium-containing biomaterials in otoneurosurgery for reconstitution of bone in contact with cerebrospinal fluid (CSF) also led to cases of encephalopathy and death. We report aluminium (Al) concentrations in the biological fluids of six French patients following use of Al-containing bone cement in otoneurosurgery. In five patients, the mean plasma Al levels (microgram/L) were: 1.20 +/- 0.05 (case 2), 9.20 +/- 0.10 (case 3), 1.00 +/- 0.05 (case 4), 2.80 +/- 0.05 (case 5) and 2.00 +/- 0.05 (case 6). In case 1, Al concentrations were 176 micrograms/L in the postauricular CSF accumulation, 34 micrograms/L in the pontocerebellar angle and 4 and 6 micrograms/L in the lumbar shunt. As a precautionary measure, in the first three cases the biomaterial was removed soon after the intervention, and no increase in plasma or CSF Al was observed. In the other cases, absence of neurobiological symptoms and normal concentrations of Al in plasma led neurosurgeons not to extract this biomaterial. Al assay thus may be considered to be a complementary and at times a decision-generating factor. Care is needed at all stages from sampling through analysis because Al is ubiquitous and factually high results may be clinically misleading. Herein, such considerations are discussed in conjunction with the neurotoxicity of this metal in man. In addition, the authors call for in-depth preliminary trials of these biomaterials in animals prior to introduction on the market.

[Results of hearing preservation in surgery of vestibular schwannoma. Value of combined retrosigmoid and middle fossa approaches]. / Résultats de la conservation de l'audition dans la chirurgie du schwannome vestibulaire. Intérêt de la voie combinée sus-pétreuse et rétrosigmoïde.

We report our experience of hearing preservation in acoustic neurinoma surgery, using combined retrosigmoid and middle fossa approaches. Fifty neurinomas operated on between 1987 and 1994 were included in this retrospective study. Hearing preservation surgery was performed for patients with grade II or grade III tumors (mean average tumor diameter: 14.4 mm), presenting with normal or serviceable pre-operative hearing (pure tonal average decrease less than 50 dB, speech discrimination score better than 50%). Isolated middle fossa approach was used in 3 cases, isolated retrosigmoid approach in 2 cases. The 45 other cases were operated on using both routes during the same procedure. Total removal of the tumor with anatomic facial preservation was performed in all cases. No death occurred. The facial function assessed 3 months after surgery was good in 84% of cases (House-Brackmann grades I or II). The mean follow-up was 42 months. Post-operative hearing was measurable in 48% of cases and serviceable in 30% of cases. The size of the tumor and the level of preoperative hearing appear to be the most important predictive criteria for successful hearing preservation.

[Problem of the preservation of hearing in acoustic neuroma. Value of the mixed supra petrous and retrosigmoid approach]. / Le problème de la conservation de l'audition dans les neurinomes de l'acoustique. Intérêt de la voie d'abord mixte sus-pétreuse et rétro-sigmoïde.

The authors described their experience of the possibilities of preservation of hearing on the basis of a series including approximately 180 acoustic neurinomas. Whilst the initial experimental approach involving the use of a sub-occipital approach in seated position was abandoned, in view of the risk of complications inherent to the use of this approach, the authors progressively developed the possibility of the preservation of hearing by a retro-sigmoid approach in horizontal position as described in France by Bremond, Magnand and Garcin, and taken up subsequently by Sterkers. Currently, a retro-sigmoid approach is used combined with a classical supra petral approach which can be used in all cases to assess the tumour at the base of the internal auditory meatus and identify the position of the facial nerve. This surgery by mixed approach can safeguard hearing in small tumours (grades I, II and IIIa) in approximately 75% of cases. Functional hearing should nevertheless be differentiated (approximately one case out of two) in other cases where only residual auditory tissue remains. It is highly likely that improvement in radiological techniques (leading to earlier diagnosis) as well as surgical techniques will lead to the safeguard of hearing in even more cases, and hence the importance of evaluation of these techniques in terms of their relative indication in comparison with the translabyrinthine approach which the authors consider to remain the approach of choice in large tumours (grades IIIb and IV).

[Value of vestibular neurectomy using the suprapetrosal approach in the treatment of Menière's disease]. / Intérêt de la neurectomie vestibulaire par voie sus-pétreuse dans le traitement de la maladie de Ménière.

Results of a suprapetrosal approach to vestibular neurectomy for the treatment of Meniere's disease in 60 patients between 1974 and 1984 (ORL clinic, Lille) demonstrated the benign nature of the operation and its efficacy (94.5% recovery rate). However, deafness is in no way altered, there is a relatively high risk of severe paralysis (3 patients--approximately 5%) and sequelae consist of typical facial hemispasm. The operation should be reserved for patients with severe Meniere's disease resistant to medical treatment. It is a difficult surgical procedure requiring a minutiose technique with identification of all guides described in the literature (blue line of superior semicircular canal and angle of Fisch, petrosal nerves, superior petrosal sinus). This operation is preferred to that of other approaches (retrolabyrinthic and retrosigmoid), since section of vestibular nerves in the pontocerebellar angle involves a greater theoretical vital risk (particularly by possible lesion of the vascular system of cerebellar arteries) and a risk of postoperative liquorrhea. Long-term risks are dominated by onset of bilateralization of the disease, an event which is however only moderately frequent (10% of patients).

[Solitary tumors of the vagus nerve in the carotid sulcus: neurofibroma and schwannoma. Apropos of 2 cases]. / Tumeurs solitaires du pneumogastrique dans la gouttière carotidienne: neurofibrome et schwannome. A propos de deux cas.

Neurinoma of the vagus is a rare disease (less than a hundred cases published) and even more exceptional when it develops in the carotid cervical sulcus. Indeed, nevous tumors of the neck are usually situated in a high position, in the lateo-pharyngeal space. Clinical diagnosis is difficult: a chronical enlarged lymph node is the usual suggestion. Nevertheless, two signs, albeit inconsistent are very important: cough and bradycardia on palpation of the tumefaction. Enucleation, when possible, is the best procedure for exeresis, leaving the recurrent fibers intact. But in most cases, the tumor cannot be separated from the nervous fibers and the vagus nerve must be severed at both ends. This results in definitive paralysis of the homolateral vocal cord. Microscopically, it is not always easy to distinguish between neurofibroma and schwannoma because both tumors share a common cytogenetic origin and many intermediary forms are found. Only electronic microscopy can solve litigious cases. The importance of this distinction is not only speculative, a schwannoma assumes a solitary course but a neurofibroma may belong to Recklinghausen's disease. Both schwannoma and the rare solitary neurofibroma of the cervical portion of the vagus nerve can be surgically removed, their prognosis is favorable. nervous tumors of the neck in Recklinghausen's Disease must not be operated on account of possible aggravation.

[Electrogustometric threshold in diabete and chronic ethylism. Survey on 230 patients (author's transl)]. / Le seuil électrogustométrique dans le diabète sucré et l'éthylisme chronique. (Enquête sur 230 malades).

This study completes a previous one in which the authors tested the electrogustometric threshold in 300 normal subjects used as controls. The collected datas has been computerized on a programable calculator according to a lognormal model. Comparison between the electrogustometric threshold in diabetic patients, ethylic ones and controls demonstrate that they are statistically different. More than a half of the diabetics and ethylics have abnormaly high electrogustometric thresholds. The responses have been studied as a function of the evolution of the disease, of the clinical form and of gravity. Diabete and chronic ethylism do not disturb the gustatic function at the same speed and with the same intensity: one year evolution is at least necessary for diabetics, and ten years for ethylics in order to detect abnormal electrogustometric thresholds. But if the action of ethylic intoxication is slower, it determines the most important gustometric deteriorations.