Nonprogrammable Shunts for Communicating Hydrocephalus and Three-Dimensional Volumetry: A Retrospective Analysis.

Objective: Although the use of different types of valves has been extensively studied in shunt surgery for communicating hydrocephalus (cHC), a consensus about the valve type remains absent. The objective of this study is to evaluate our results with the primary placement of nonprogrammable valves (NPVs) for this indication.

Methods: We retrospectively analyzed all first NPVs implanted between 2014 and 2020 for cHC. We studied the revision rate, clinical outcome described by modified Rankin Scale (mRS), and radiologic evolution using Evans Index (EI) and ventricular volumes three-dimensional semi-automatic segmentation (vv-3DSAS).

Results: Forty-one patients were shunted for posthemorrhagic (61%), posttraumatic (24.4%), and tumoral (14.6%) hydrocephalus. Mean age was 65 years (range, 25-89 years). Overall, 59 procedures were performed including 18 revision surgeries in 12 patients (29.3%). The underlying reasons for first shunt revision were valve type related (valve dysfunction, overdrainage, and underdrainage) and nonvalve type related (malpositioning, infection, and shunt migration). The shunt-related revision rate was 17.1%. Twenty-eight patients (68.3%) had an mRS score improvement of 1 or more points. We found a good correlation between ventricle volumes (VV) and EI and a significant reduction in VV measured by EI and vv-3DSAS was observed. However, the mRS improvement was not correlated with a reduction in ventricle volumes.

Conclusions: Overall, our results in terms of shunt revisions as well as clinical and radiologic evolution are comparable to the literature for NPV. vv-3DSAS can be used and could be useful to detect small changes in VV in patients with cHC.