gms | German Medical Science

Objective: Implantation of a vp-shunt represents the current standard of care in hydrocephalus patients. Both combination valves implanted in this study contain a proprietary differential pressure valve, which is combined with a gravity-regulated anti-siphon device (ASD) in the proGAV (PG) valve and with a flow-controlled ASD in the CertasPlus (CP) valve. We sought to investigate whether the risk and performance profile differs in the two combination valves.

Methods: Assignment of patients to valve type was block randomized in this prospective observational study. The sample consisted of 79 adult patients with hydrocephalus who received a vp-shunt for the first time. The two largest diagnostic subgroups (66 patients in total) were analyzed, namely iNPH (44%, n=35) and secondary communicating hydrocephalus (39%, n=31). Analyzed frontal occipital horn ratio (FOHR) and Evans index were CT derived. FOHR, Evans index and Stein-Langfitt (SL) scores were assessed prior to valve implantation and at follow-up. Black grading scale was assessed at follow-up only.

Results: In this intermediate analysis, patients with iNPH compared to patients with secondary communicating hydrocephalus were significantly younger (75 ± 6 years vs. 58 ± 15 years, p<0.01). In patients with secondary communicating hydrocephalus , FOHR and Evans index tended to improve due to valve-treatment (p= 0.10 and p= 0.24) while SL scores improved significantly (p=0.015). No difference between valve types was found, neither on level (p≥ 0.29) nor on time-course (p≥ 0.37). In patients with iNPH, FOHR and Evans score changed significantly due to valve treatment (p≤ 0.01 and show a tendency for improvement of Stein-Langfitt (p= 0.067). Of note, in patients with iNPH, FOHR, Evans, and SL scores prior to valve-implantation had been significantly lower in CP compared to PG (p = 0.0021 multivariate joint test). Postoperative change in Evans (p=0.95) and FOHR did not differ significantly (p=0.39) and no differences were observed in median SL nor Black scale between valves (p=0.64). There were 2 revisions in the PG group (1 wound dehiscence, 1 cranial catheter occlusion) and none in the CP group. No difference in number of valve adjustments between CP and PG (p=0.24) was observed in both hydrocephalus subtypes.

Conclusion: VP-shunt insertion for treatment of hydrocephalus can be performed safely and effectively with both valve types. No difference in outcome was noted between both valve types.