One-year outcome in patients with idiopathic normal-pressure hydrocephalus: comparison of lumboperitoneal shunt to ventriculoperitoneal shunt

Idiopathic normal pressure hydrocephalus (iNPH) is treated with cerebrospinal fluid shunting, and implantation of a ventriculoperitoneal shunt (VPS) is the current standard treatment. The objective of this study was to compare the efficacy and safety of VPSs and lumboperitoneal shunts (LPSs) for patients with iNPH. METHODS The authors conducted a prospective multicenter study of LPS use for patients with iNPH. Eighty-three patients with iNPH (age 60 to 85 years) who presented with ventriculomegaly and high-convexity and medial subarachnoid space tightness on MR images were recruited from 20 neurological or neurosurgical centers in Japan between March 1, 2010, and October 19, 2011. The primary outcome was the modified Rankin Scale (mRS) score 1 year after surgery, and the secondary outcome included scores on the iNPH grading scale (iNPHGS). A previously conducted VPS cohort study with the same inclusion criteria and primary and secondary end points was used as a historical control. RESULTS The proportion of patients who achieved a favorable outcome (i.e., improvement of at least 1 point in their mRS score) was 63% (95% CI 51%-73%) and was comparable to values reported with VPS implantation (69%, 95% CI 59%-78%). Using the iNPHGS, the 1-year improvement rate was 75% (95% CI 64%-84%) and was comparable to the rate found in the VPS study (77%, 95% CI 68%-84%). The proportion of patients experiencing serious adverse events (SAEs) and non-SAEs did not differ significantly between the groups at 1 year after surgery (SAEs: 19 [22%] of 87 LPS patients vs 15 [15%] of 100 VPS patients, p = 0.226; non-SAEs: 24 [27.6%] LPS patients vs 20 [20%] VPS patients, p = 0.223). However, shunt revisions were more common in LPS-treated patients than in VPS-treated patients (6 [7%] vs [1%]). CONCLUSIONS The efficacy and safety rates for LPSs with programmable valves are comparable to those for VPSs for the treatment of patients with iNPH. Despite the relatively high shunt failure rate, an LPS can be the treatment of choice because of its minimal invasiveness and avoidance of brain injury.