A randomized controlled dual-center trial on shunt complications in idiopathic normal-pressure hydrocephalus treated with gradually reduced or “fixed” pressure valve settings

Abstract

I dIopathIc normal pressure hydrocephalus (iNPH) is a treatable condition, first described by Hakim in 1965. 10 It is characterized clinically by gait disturbance, cognitive impairment, and urinary incontinence and radiologically by ventriculomegaly. The condition is typically diagnosed in the elderly and most often treated by insertion of a ventriculoperitoneal (VP) shunt with either a fixed or an adjustable pressure valve. Adjustable valves were designed to lower the complication rate and optimize the effect of shunting. 26 After shunt surgery in iNPH patients, improvement rates between 61% and 90% have been reported, 6,[11][12][13][14]16,18,23 with recent studies revealing a rate above 80%. 13,24 The complication rates are high, up to 50%, 3,8,22 although a rate of 20% is evident in recent studies. 8,26 The major complications are mechanical obstruction, infection, and subdural hematoma (SDH); the frequency of SDH is between 2% and 16%. 7,13,23 A Dutch NPH study recommended the use of a low A randomized controlled dual-center trial on shunt complications in idiopathic normal-pressure hydrocephalus treated with gradually reduced or "fixed" pressure valve settings Object. This study was undertaken to investigate whether a gradual reduction of the valve setting (opening pressure) decreases the complication rate in patients with idiopathic normal-pressure hydrocephalus (iNPH) treated with a ventriculoperitoneal (VP) shunt.Methods. In this prospective double-blinded, randomized, controlled, dual-center study, a VP shunt with an adjustable valve was implanted in 68 patients with iNPH, randomized into two groups. In one group (the 20-4 group) the valve setting was initially set to 20 cm H 2 O and gradually reduced to 4 cm H 2 O over the course of the 6-month study period. In the other group (the 12 group), the valve was kept at a medium pressure setting of 12 cm H 2 O during the whole study period. The time to and type of complications (hematoma, infection, and mechanical problems) as well as overdrainage symptoms were recorded. Symptoms, signs, and outcome were assessed by means of the iNPH scale and the NPH grading scale.Results. Six patients in the 20-4 group (22%) and 7 patients in the 12 group (23%) experienced a shunt complication; 9 had subdural hematomas, 3 mechanical obstructions, and 1 infection (no significant difference between groups). The frequency of overdrainage symptoms was significantly higher for a valve setting ≤ 12 cm H 2 O compared with a setting > 12 cm H 2 O. The 20-4 group had a higher improvement rate (88%) than the 12 group (62%) (p = 0.032). There was no significant relationship between complications and body mass index, the use of an antisiphon device, or the use of anticoagulants.Conclusions. Gradual lowering of the valve setting to a mean of 7 cm H 2 O led to the same rate of shunt complications and overdrainage symptoms as a fixed valve setting at a mean of 13 cm H 2 O but was associated with a significantly better outcome. (http://thejns.org/doi/abs/10.3171/2014.7.JNS14283) Key Wo...

A double-blind randomized trial on the clinical effect of different shunt valve settings in idiopathic normal pressure hydrocephalus

“…20 The reason for the apparent discrepancy between our 2 articles is that they are based on different methods. First, our current article defines the results based on a set of objective tests while the previous article was partly based on the patient's subjective descriptions of the overall effect during the followup period.…”

“…12 The complication rate between the 2 groups (20-4 and 12) was recently published, showing no significant difference in the complication rate. 20 To our knowledge, this is the first RCT to explore the clinical effect of lowering the valve setting. Previous nonrandomized and nonblinded studies 2,4,6,27 have indicated that changing the opening pressure may have significant effects on symptoms and signs.…”

“…Adjustable shunts seem valuable for the management of complications, such as SDH and effusions, as well as symptoms related to over-and underdrainage. 20 For the practical purpose of repeated evaluations, it was important to select easy to administer tests from the iNPH scale for this study. The 4 tests were carefully chosen to prevent the risk of learning effects leading to improved test results.…”

“…As we have recently published, the same rate of SDH was observed in patients with and without ASD, but a significantly higher rate of overdrainage symptoms was seen in the patients without ASD (p = 0.002). 20 The sample size of 60 was deemed appropriate based on the assumption of a complication rate of 30% (SD 8%) and a power of 90%. At the time we planned the study no data were available on the expected clinical effect.…”

Surgical Treatment for Leptomeningeal Disease

“…Such changes are not always seen in patients with leptomeningeal disease because of its acuity. 42 Nevertheless, overdrainage can occur and the neurosurgeon should be aware of such complications.…”