Assessment of a quick reference table algorithm for determining initial postoperative pressure settings of programmable pressure valves in patients with idiopathic normal pressure hydrocephalus: SINPHONI subanalysis.

BACKGROUND: Management of overdrainage complications in shunted patients with idiopathic normal pressure hydrocephalus (INPH) remains a difficult task despite the use of programmable pressure valves.

OBJECTIVE: To assess the usefulness of a quick reference table (QRT) algorithm for achieving a suitable initial programmable pressure valve setting in INPH patients who participated in the Study for INPH on Neurological Improvement (SINPHONI).

METHODS: One hundred registered patients diagnosed with probable INPH were treated with ventriculoperitoneal shunts using Codman-Hakim programmable valves (CHPVs). In this series, the initial CHPV setting was decided prospectively according to the QRT algorithm. Shunt effectiveness, complications, and the number of CHPV readjustments during follow-up periods were investigated.

RESULTS: Eighty patients were considered better than shunt responders (more than 1 point improvement in modified Rankin scale at any follow-up period). Readjustments of CHPVs within 3 months after treatment with ventriculoperitoneal shunt were performed 56 times in 44 cases (44%, 0.56 times/patient). Low-pressure headache occurred in 9 patients, all of whom improved by readjustment alone. Nontraumatic subdural fluid collections and chronic subdural hematomas occurred in 15 cases (15%); however, most of the cases were subclinical and improved after CHPV readjustments alone. Burr hole irrigation was necessary in only 1 case.

CONCLUSION: Use of the QRT algorithm was associated with a decrease in postoperative CHPV readjustments and serious overdrainage complications during the follow-up period. The QRT algorithm is an easy, safe, and effective method for determining the initial CHPV pressure setting in INPH patients.