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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.