Programmable gravitational valves in idiopathic normal pressure hydrocephalus: long-term outcomes after a 3-year follow-up.

Abstract

The development of shunting valve technologies for the surgical treatment of idiopathic normal pressure hydrocephalus (iNPH) has advanced significantly over the decades, with adjustable gravitational valves (GV) emerging as a promising alternative to traditional fixed-pressure valves. This study aimed to investigate the safety and effectiveness of adjustable GV for the surgical treatment of iNPH after a 3-year follow-up. Adult patients treated with ventriculoperitoneal shunt (VPS) using programmable GVs were retrospectively evaluated. Neurological outcome was assessed according to the iNPH Grading Scale (INPHGS). Postoperative early and late complications, pre- and post-implantation pressure settings, and type and number of post-implantation pressure adjustments were recorded at each follow-up. A total of 76 patients were evaluated, with a median postoperative follow-up of 36 (24-42) months. The mean preoperative and postoperative iNPHGS scores were 4.2 ± 1.6 and 3.5 ± 1.5, respectively, demonstrating a significant overall clinical improvement after VPS surgery (p < 0.001). Overall, 7 (9.2%) patients required surgical intervention due to late complications. No cases of valve dysfunction were reported. During follow-up, 54 (71.1%) patients underwent valve setting adjustments, with a median number of post-implantation valve setting modifications of 1. No significant associations were found between postoperative outcomes and preoperative characteristics including age and initial opening pressure parameters. Adjustable GVs are a safe and effective alternative to traditional fixed differential pressure valves for the surgical treatment of iNPH. After a 3-year follow-up, the overall postoperative complication rate was acceptable, with a significantly lower rate of valve dysfunction compared to previous literature findings.