Secondary deterioration in patients with normal pressure hydrocephalus after ventriculoperitoneal shunt placement: a proposed algorithm of treatment

Abstract

Background: After ventriculoperitoneal shunt surgery for idiopathic normal pressure hydrocephalus (iNPH) with adjustable gravitational valves, a certain proportion of patients develop secondary clinical worsening after initial improvement of clinical symptoms. The aim of this study was to analyze this group of patients with secondary deterioration and to evaluate the performed shunt management. Methods: For this investigation, we retrospectively reviewed our NPH registry for patients included between 1999 and 2013 with a decrease by a minimum of two points in the Kiefer score in the first year of follow up and an increase of two points in the Kiefer score between the second and the fifth year after shunt surgery (secondary deterioration). Then, we analyzed the patient's shunt management (adapting the valve pressure setting, shuntography, valve replacement, catheter replacement, implant an adjustable gravitational unit). Additionally, we searched for risk factors for secondary deterioration. Results: Out of 259 iNPH patients, 53 (20%) patients showed secondary deterioration on an average of 2.7 (2-4 years) years after shunt surgery. Fourteen (26%) patients with secondary deterioration improved after shunt or valve management and 58% remained without clinical benefit after management. We had a drop-out rate of 15% due to incomplete datasets. Our shunt management reduced the rate of secondary deterioration from 20 to 15%. On the basis of our findings, we developed an algorithm for shunt management. Risk factors for secondary deterioration are the age of the patient at the time of shunting, newly diagnosed neurodegenerative diseases, and overdrainage requiring adjusting the valve to higher-pressure levels. Conclusion: Twenty percent of patients with iNPH were at risk for secondary clinical worsening about 3 years after shunt surgery. About one-fourth of these patients benefited for additional years from pressure level management and/or shunt valve revision. Our findings underline the need for long-term follow-ups and intensive shunt management to achieve a favorable long-term outcome for patients with iNPH and VPS.

Shunt Overdrainage: Reappraisal of the Syndrome and Proposal for an Integrative Model

“…Continuous clinical improvement may be obtained by decreasing opening pressure (if necessary, down to 0 mmH 2 O) and secondary responses can be obtained in initially non-responder patients [120,121]. NPH may even evolve to a "ultra-low-pressure" hydrocephalic state and downgrading valves and gravitational units may facilitate a "therapeutic siphoning" effect [122][123][124]. Barami's theory of uncontrolled cerebral venous overdrainage might explain why patients remain symptomatic even despite the addition of an ASD [97].…”

Using smartphone-based accelerometers to gauge postoperative outcomes in patients with NPH: Implications for ambulatory monitoring

“…This finding is especially noteworthy as a certain proportion of patients develop a second clinical deterioration after initial improvement in clinical symptoms. [ 7 ] In the pertinent literature, up to 20% of patients will experience secondary deterioration, with some amendable to shunt management and/or shunt revision. [ 8 ] On examination, our patient did not report a worsening in symptoms, so the shunt settings were held at 1.5.…”

Gravitational shunt valves in hydrocephalus to challenge the sequelae of over-drainage

“…The success rate after implantation of a VP shunt is up to 90% [62,63]. However, the success rate seems to decrease over the long term [62,64].…”