[Stereotaxic ventriculocisternostomy in the treatment of triventricular obstructive hydrocephalus. Apropos of 23 cases].

UNLABELLED

During the period January 1975-October 1987, we performed stereotactic ventriculocisternostomy (V.C.S.) on 23 patients (13 M., 10 F.; age: 11-73 years, m: 33). Sometimes used as an isolated therapeutic procedure, V.C.S. may also follow stereotactic biopsies using Talairach's methodology. Serial stereotactic biopsies were performed in 15 out of 23 patients showing 11 tumoral lesion, two arachnoïdal cysts and two cryptic vascular malformations. Eight patients presented with an isolated aqueductal stenosis. Among the 12 non tumoral patients, seven had very large triventricular hydrocephalus (6 with a retroclival dilatation of the third ventricle) and 5 showed significant dilatation. Of the 11 tumoral patients, 7 had significant ventricular dilatation (1 with a protrusion of the floor of the third ventricle) and 4 with modest dilation. V.C.S. is done by creating an opening (diameter: 5-6 mm) in the floor of third ventricle with a fine forceps introduced through a tubular guide (diameter: 2.45 mm). The percutaneous double oblique transfrontal trajectory (drill-hole: 2.5 mm of diameter) passing through the foramina of Monro, avoids superficial and deep vessels visualised on the previous Stereoscopic Tele-Angiographic and Ventriculographic study. A systematic verification of the V.C.S. patency is made intraoperatively by injection of iodine contrast medium into the third ventricle.

RESULTS

(non tumoral patients: 12) (m follow-up: 4 years): two patients needed a ventricular shunt after 3 and 1 months respectively, the first one because of an associated communicant hydrocephalus, the second because of a post-operative meningeal infection. Long-term clinical and CT-Scan follow-up showed that complete resolution (7 cases) or partial (2 cases) improvement of symptoms and signs was not accompanied by normalization of ventricular size, even though the dilatation was significantly reduced in 8 cases and to a lesser extent in 2.

RESULTS

(tumoral patients: 11) (m follow-up: 3 years). Hydrocephalus was reduced in 6 cases and remained unchanged in 5. Two patients needed a ventricular shunt 2 years after the V.C.S.: 1 patient, because of a tumoral recurrence involving the region of the fenestration, the second patient because of adhesive arachnoiditis following reoperation for suspicion of recurrence, though this was found to be granulomatous inflammation. Two patients died as a result of their tumors at 2 and 6 years.

CONCLUSION

Stereotactic V.C.S. is the treatment of choice for triventricular obstructive hydrocephalus even when there is no retroclival dilatation of the floor of the third ventricle.