[Opaque meato-cisternography in study of atypical or incomplete syndromes of cerebellopontile angle (value for diagnosis and early treatment of neurilemmoma of the 8)].

It is well-known today that there is a cisternal "no man's land" between the petrous bone and the cerebral trunk in which a tumour can develop insidiously. The clinical signs are very variable and often in contradiction with those described for larger tumours. Tomodensimetry is indicated, but it is not conclusive if the mass is limited to the internal auditory canal or if it extends into the angle for less than 15 mm. Opaque meato-cisternography alone, gives the following information: 1. When a pseudo-tumoural syndrome is present, the auditory canal and cisterna are well opacified. 2. If there is a tumour which extends for more than 20 mm into the cisterna, the oil has a rounded, interrupted contour, and other radiological examinations are useful in this case. 3. When the tumour extends for less than 20 mm into the angle a rounded continuous contour is seen, and Hirtz's axial incidence can be used to measure the tumour diameter. 4. Finally, when temporary opacification faults have been eliminated (after retilting), opaque meato-cisternography is the only examination able to demonstrate the early stages of a tumour, in the intra-canal stage. This early diagnostic procedure has enabled one of us to excise tumours of moderate of even very small volume, under the best surgical conditions, and with functional and vital results which we would not have obtained at a later date.