Outcomes and complications of different surgical treatments for idiopathic normal pressure hydrocephalus: a systematic review and meta-analysis.

OBJECTIVEDifferent CSF diversion procedures (ventriculoperitoneal, ventriculoatrial, and lumboperitoneal shunting) have been utilized for the treatment of idiopathic normal pressure hydrocephalus. More recently, endoscopic third ventriculostomy has been suggested as a reasonable alternative in some studies. The purpose of this study was to perform a systematic review and meta-analysis to assess overall rates of favorable outcomes and adverse events for each of these treatments. An additional objective was to determine the outcomes and complication rates in relation to the type of valve utilized (fixed vs programmable).METHODSMultiple databases (PubMed, Ovid MEDLINE In-Process & Other Non-Indexed Citations, Ovid MEDLINE, Ovid Embase, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus) were searched for studies involving patients with idiopathic ventriculomegaly, no secondary cause of hydrocephalus, opening pressure < 25 mm Hg on high-volume tap or drainage trial, and age > 60 years. Outcomes included the proportion of patients who showed improvement in gait, cognition, and bladder function. Adverse events considered in the analysis included postoperative ischemic/hemorrhagic complications, subdural fluid collections, seizures, need for revision surgery, and infection.RESULTSA total of 33 studies, encompassing 2461 patients, were identified. More than 75% of patients experienced improvement after shunting, without significant differences among the different techniques utilized. Overall, gait improvement was observed in 75% of patients, cognitive function improvement in more than 60%, and improvement of incontinence in 55%. Adjustable valves were associated with a reduction in revisions (12% vs 32%) and subdural collections (9% vs 22%) as compared to fixed valves.CONCLUSIONSOutcomes did not differ significantly among different CSF diversion techniques, and overall improvement was reported in more than 75% of patients. The use of programmable valves decreased the incidence of revision surgery and of subdural collections after surgery, potentially justifying the higher initial cost associated with these valves.

Usefulness of the convexity apparent hyperperfusion sign in 123I-iodoamphetamine brain perfusion SPECT for the diagnosis of idiopathic normal pressure hydrocephalus.

OBJECTIVE: The gold standard for the diagnosis of idiopathic normal pressure hydrocephalus (iNPH) is the CSF removal test. For elderly patients, however, a less invasive diagnostic method is required. On MRI, high-convexity tightness was reported to be an important finding for the diagnosis of iNPH. On SPECT, patients with iNPH often show hyperperfusion of the high-convexity area. The authors tested 2 hypotheses regarding the SPECT finding: 1) it is relative hyperperfusion reflecting the increased gray matter density of the convexity, and 2) it is useful for the diagnosis of iNPH. The authors termed the SPECT finding the convexity apparent hyperperfusion (CAPPAH) sign. METHODS: Two clinical studies were conducted. In study 1, SPECT was performed for 20 patients suspected of having iNPH, and regional cerebral blood flow (rCBF) of the high-convexity area was examined using quantitative analysis. Clinical differences between patients with the CAPPAH sign (CAP) and those without it (NCAP) were also compared. In study 2, the CAPPAH sign was retrospectively assessed in 30 patients with iNPH and 19 healthy controls using SPECT images and 3D stereotactic surface projection. RESULTS: In study 1, rCBF of the high-convexity area of the CAP group was calculated as 35.2­43.7 ml/min/100 g, which is not higher than normal values of rCBF determined by SPECT. The NCAP group showed lower cognitive function and weaker responses to the removal of CSF than the CAP group. In study 2, the CAPPAH sign was positive only in patients with iNPH (24/30) and not in controls (sensitivity 80%, specificity 100%). The coincidence rate between tight high convexity on MRI and the CAPPAH sign was very high (28/30). CONCLUSIONS: Patients with iNPH showed hyperperfusion of the high-convexity area on SPECT; however, the presence of the CAPPAH sign did not indicate real hyperperfusion of rCBF in the high-convexity area. The authors speculated that patients with iNPH without the CAPPAH sign, despite showing tight high convexity on MRI, might have comorbidities such as Alzheimer's disease.

Why Does the Health-Related Quality of Life in Idiopathic Normal-Pressure Hydrocephalus Fail to Improve Despite the Favorable Clinical Outcome?

OBJECTIVE: Occasionally, a favorable clinical disease-specific outcome does not reflect into improved generic health-related quality of life (HRQoL) in patients with idiopathic normal-pressure hydrocephalus (iNPH) at 1 year after the installation of a cerebrospinal fluid shunt. Our aim was to identify factors causing this discrepancy. METHODS: The 1-year HRQoL outcomes of 141 patients with iNPH were evaluated with the generic 15D instrument, in which the minimum clinically important change/difference on the 0-1 scale has been estimated to be ±0.015. A 12-point iNPH grading scale (iNPHGS) was used as a clinical disease-specific outcome measure, in which a 1-point decrease is considered to be clinically important. We identified 29 (21%) patients with iNPH from our prospective study whose HRQoL deteriorated or remained the same despite of a favorable iNPHGS outcome. We analyzed this discrepancy using patients' clinical variables and characteristics. RESULTS: Multivariate binary logistic regression analysis indicated that a greater (worse) iNPHGS score at baseline (adjusted odds ratio [OR], 1.7; 95% confidence interval [CI] 1.3-2.3; P < 0.001), comorbid chronic pulmonary disease (40% vs. 20%; adjusted OR 17.8; 95% CI 3.6-89.9; P < 0.001), and any comorbid nonmetastatic tumor (62% vs. 17%; adjusted OR 11.5; 95% CI 1.5-85.3; P = 0.017) predicted discrepancy between iNPHGS and 15D outcomes. CONCLUSIONS: Frail patients suffering from certain pre-existing comorbidities may not experience improvement in generic HRQoL despite of a favorable clinical disease-specific response. Acknowledging the comorbidity burden of the patient may help clinicians and the patients to understand the conflict between patient-reported and clinical outcomes.

Disability risk or unimproved symptoms following shunt surgery in patients with idiopathic normal-pressure hydrocephalus: post hoc analysis of SINPHONI-2.

OBJECTIVE The study aim was to assess the influence of presurgical clinical symptom severity and disease duration on outcomes of shunt surgery in patients with idiopathic normal-pressure hydrocephalus (iNPH). The authors also evaluated the cerebrospinal fluid tap test as a predictor of improvements following shunt surgery. METHODS Eighty-three patients (45 men and 38 women, mean age 76.4 years) underwent lumboperitoneal shunt surgery, and outcomes were evaluated until 12 months following surgery. Risks for poor quality of life (Score 3 or 4 on the modified Rankin Scale [mRS]) and severe gait disturbance were evaluated at 3 and 12 months following shunt surgery, and the tap test was also conducted. Age-adjusted and multivariate relative risks were calculated using Cox proportional-hazards regression. RESULTS Of 83 patients with iNPH, 45 (54%) improved by 1 point on the mRS and 6 patients (7%) improved by ≥ 2 points at 3 months following surgery. At 12 months after surgery, 39 patients (47%) improved by 1 point on the mRS and 13 patients (16%) improved by ≥ 2 points. On the gait domain of the iNPH grading scale (iNPHGS), 36 patients (43%) improved by 1 point and 13 patients (16%) improved by ≥ 2 points at 3 months following surgery. Additionally, 32 patients (38%) improved by 1 point and 14 patients (17%) by ≥ 2 points at 12 months following surgery. In contrast, 3 patients (4%) and 2 patients (2%) had worse symptoms according to the mRS or the gait domain of the iNPHGS, respectively, at 3 months following surgery, and 5 patients (6%) and 3 patients (4%) had worse mRS scores and gait domain scores, respectively, at 12 months after surgery. Patients with severe preoperative mRS scores had a 4.7 times higher multivariate relative risk (RR) for severe mRS scores at 12 months following surgery. Moreover, patients with severe gait disturbance prior to shunt surgery had a 46.5 times greater multivariate RR for severe gait disturbance at the 12-month follow-up. Patients without improved gait following the tap test had multivariate RRs for unimproved gait disturbance of 7.54 and 11.2 at 3 and 12 months following surgery, respectively. Disease duration from onset to shunt surgery was not significantly associated with postoperative symptom severity or unimproved symptoms. CONCLUSIONS Patients with iNPH should receive treatment before their symptoms become severe in order to achieve an improved quality of life. However, the progression of symptoms varies between patients so specific timeframes are not meaningful. The authors also found that tap test scores accurately predicted shunt efficacy. Therefore, indications for shunt surgery should be carefully assessed in each patient with iNPH, considering the relative risks and benefits for that person, including healthy life expectancy.

Utility of MRI-based disproportionately enlarged subarachnoid space hydrocephalus scoring for predicting prognosis after surgery for idiopathic normal pressure hydrocephalus: clinical research.

OBJECTIVE The presence of disproportionately enlarged subarachnoid space hydrocephalus (DESH) on brain imaging is a recognized finding of idiopathic normal pressure hydrocephalus (iNPH), but the features of DESH can vary across patients. The aim of this study was to evaluate the utility of MRI-based DESH scoring for predicting prognosis after surgery. METHODS In this single-center, retrospective cohort study, the DESH score was determined by consensus between a group of neurosurgeons, neurologists, and a neuroradiologist based on the preoperative MRI findings of the patients with suspected iNPH. The DESH score was composed of the following 5 items, each scored from 0 to 2 (maximum score 10 points): ventriculomegaly, dilated sylvian fissures, tight high convexity, acute callosal angle, and focal sulcal dilation. The association between the DESH score and improvement of the scores on the modified Rankin Scale (mRS), iNPH Grading Scale (iNPHGS), Mini-Mental State Examination (MMSE), Trail Making Test-A (TMT-A), and Timed 3-Meter Up and Go Test (TUG-t) was examined. The primary end point was improvement in the mRS score at 1 year after surgery, and the secondary outcome measures were the iNPHGS, MMSE, TMT-A, and TUG-t scores at 1 year after surgery. Improvement was determined as improvement of 1 or more levels on mRS, ≥ 1 point on iNPHGS, ≥ 3 points on MMSE, a decrease of > 30% on TMT-A, and a decrease of > 10% on TUG-t. RESULTS The mean DESH score for the 50 patients (mean age 77.6 ± 5.9 years) reviewed in this study was 5.58 ± 2.01. The mean rate of change in the mRS score was -0.50 ± 0.93, indicating an inverse correlation between the DESH score and rate of change in the mRS score (r = -0.749). Patients who showed no improvement in mRS score tended to have a low DESH score as well as low preoperative MMSE and TMT-A scores. There were no differences in the areas of deep white matter hyperintensity and periventricular hyperintensity on the images between patients with and without an improved mRS score (15.6% vs 16.7%, respectively; p = 1.000). The DESH score did differ significantly between patients with and without improved scores on the iNPHGS (6.39 ± 1.76 vs 4.26 ± 1.69, respectively; p < 0.001), MMSE (6.63 ± 1.82 vs 5.09 ± 1.93; p = 0.010), TMT-A (6.32 ± 1.97 seconds vs 5.13 ± 1.93 seconds; p = 0.042), and TUG-t (6.48 ± 1.81 seconds vs 4.33 ± 1.59 seconds; p < 0.001). CONCLUSIONS MRI-based DESH scoring is useful for the prediction of neurological improvement and prognosis after surgery for iNPH.

Default mode network connectivity in patients with idiopathic normal pressure hydrocephalus.

OBJECTIVE: Idiopathic normal pressure hydrocephalus (iNPH) is a neurological disorder characterized by gait disturbance, cognitive impairment, and incontinence. It is unclear whether the pathophysiology of iNPH is associated with alterations in the default mode network (DMN). The authors investigated alterations in the DMN of patients with iNPH and sought to determine whether a relationship exists between the resting-state functional connectivity of the DMN and a patient's clinical symptoms. METHODS: Resting-state functional MRI (rs-fMRI) was performed in 16 preoperative patients with iNPH and 15 neurologically healthy control subjects of a similar age. Independent component and dual-regression analyses were used to quantify DMN connectivity. The patients' clinical symptoms were rated according to the iNPH grading scale (iNPHGS). Each of their specific clinical symptoms were rated according to the cognitive, gait, and urinary continence domains of iNPHGS, and neurocognitive status was assessed using the Mini-Mental State Examination, Frontal Assessment Battery (FAB), and Trail Making Test Part A. The strength of DMN connectivity was compared between patients and controls, and the correlation between DMN connectivity and iNPHGS was examined using both region of interest (ROI)-based analysis and voxel-based analysis. The correlation between DMN connectivity and each of the specific clinical symptoms, as well as neurocognitive status, was examined using voxel-based analysis. RESULTS: Both ROI-based and voxel-based analyses revealed reduced DMN connectivity in patients with iNPH. ROI-based analysis showed increased DMN connectivity with worsening clinical symptoms of iNPH. Consistently, voxel-based analyses revealed that DMN connectivity correlated positively with the iNPHGS score, as well as the cognitive and urinary continence domain scores, and negatively with the FAB score. The significant peak in correlation in each case was localized to the precuneus. CONCLUSIONS: This is the first study to establish alterations in the DMN of patients with iNPH. DMN connectivity may be a useful indicator of the severity of clinical symptoms in patients with iNPH.

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

OBJECTIVE 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 [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.