Clinical experience with the Sophy (R) adjustable valve in the treatment of hydrocephalus in the adult. Report on 147 cases

Objective. - Evaluate the advantages, results and drawbacks of the Sophy(R) adjustable valve (SV) in the treatment of hydrocephalus in the adult. Material and methods. - One-hundred and forty-seven adult hydrocephalic pat ients (mean age=64.5 years) shunted with a SV between 1990 and 1997 were re trospectively reviewed Etiologies of hydrocephalus were: "normal pressure" chronic hydrocephalus (NPH) in 124 and tumoral hydrocephalus with intracran ial hypertension in 23 patients. One-hundred fifty shunts were established in 147 patients: 14 ventriculoatrial and 136 ventriculoperitoneal shunts. T he initial pressure settings of the SV were : high pressure : 12 times (8 % ), medium pressure: 136 times (90.6 %) and low pressure : 2 times (1.3 %). Results. - Sixteen patients were lost to follow-rip. Two patients died with in hours following the procedure. So, the results were analyzed in the 129 remaining patients, with a follow-up of 16.7 months (+/- 17.8). Three patie nts died from shunted-related causes (2.3 %). Eighty-four patients had goon results (65 %), 25 had fair results (19.5 %) and 20 fallen to improve or d eteriorated (15.5 %) after shunting. Fifty-three reoperations were performe d in 44 patients patients (34 %), including 37 procedures for mechanical ob struction and 6 for septic complications. Subdural effusions (SDE) occurred in 16 patients (12.5 %) : 10 surgical evacuations were required in 7 patie nts; 8 patients were successfully treated using uprating of the SV pressure alone; one was managed conservatively. Fifty-eight pressure readjustments were performed in 47 patients. The pressure settings were uprated 28 times in patients showing clinical or computerized tomographic (CT) features sugg esting overdrainage; 20 of those proved to be successful (71.5 %). The pres sure settings were lowered 30 times in patients showing a lack of improveme nt after shunting, attributed to underdrainage; only 12 of those proved to be successful (40 %). Spontaneous changes of the pressure settings were obs erved in 14 patients (10.8 %). After a MRI exposure, SV pressure changes we re observed in 64 % of patients. Discussion. - The technological refinements that have been proposed to elim inate the overdrainage which occurs in most usual cerebrospinal fluid shunt s are reviewed. The SV valve has allowed non-invasive adjustments of its op ening pressure in patients showing complications ascribed to inappropriate drainage. The need for additional surgery was eliminated in 20 % to 25 % of patients of the present series. Because of frequent spontaneous and magnet ic resonance-induced pressure changes, the need for repeated controls of va lve pressure is to be reemphasized. Conclusion. - This experience suggests that the SV represents a substantial improvement over standard fixed-pressure valves.