Outcome predictors for normal-pressure hydrocephalus

Slope until reaching the plateau: a new predictor of valve response obtained by lumbar infusion test for idiopathic normal pressure hydrocephalus

BACKGROUND

Diagnosis of idiopathic normal pressure hydrocephalus (iNPH) is based on clinical, radiological, and hydrodynamic data of cerebrospinal fluid (CSF) obtained by invasive methods such as lumbar infusion test, which is used to determine the resistance to CSF outflow (Rout). However, Rout has limitations, and its value as predictor of valve response is questioned. Other variables can be obtained by lumbar infusion test, such as the time to reach the plateau (TRP) and the slope until reaching the plateau (SRP). The objectives were to determine if SRP could be a predictor of response to ventriculoperitoneal shunt (VPS) and what variable (Rout versus SRP) would have greater predictive value.

METHOD

Patients with probable iNPH who underwent a lumbar infusion test and were indicated for a VPS were retrospectively studied. Two groups were established, responders and non-responders. Rout, TRP (period between the start of infusion until reaching the plateau measured in seconds) and SRP ((plateau pressure-opening pressure)/TRP) were obtained. For Rout and SRP, the receiver operating curves (ROC) with its areas under the curve (AUC) were calculated.

RESULTS

One hundred ten patients were included, being 86 responders (78.20%). Shunt responders had a significantly greater Rout (17.02 (14.45-20.23) versus 13.34 (12.10-16.28) mmHg/ml/min, p = 0.002) and SRP (0.049 (0.043-0.054) versus 0.031 (0.026-0.036) mmHg/sec, p < 0.001) and smaller TRP (641.28 (584.83-697.73) versus 777.65 (654.03-901.27) sec, p = 0.028) than non-responders. The AUC for SRP was greater than the AUC for Rout (0.763 (95 % CI 0.655-0.871, p < 0.001) versus 0.673 (95 % CI 0.595-0.801, p = 0.008), respectively), but the differences were not significant (p = 0.180).

CONCLUSIONS

SRP could be considered predictor of response to VPS, and its accuracy tends to be better than Rout. So, this variable may be a useful tool to select shunt candidates among patients with probable iNPH.

Vascular risk factors for idiopathic normal pressure hydrocephalus: a systematic review and meta-analysis

Objective

Idiopathic normal-pressure hydrocephalus (iNPH) is a treatable cause of dementia; however, its etiology and pathogenesis remain poorly understood. The objective of this study was to investigate the prevalence and impact of vascular risk factors in patients with iNPH compared to a control cohort to better understand the potential mechanisms and preventive measures.

Methods

We systematically searched PubMed, Web of Science, Embase, and the Cochrane Library (from inception to December 20, 2022) for studies reporting vascular risk factors for the development of iNPH. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using random-effects models.

Results

After screening 1,462 articles, 11 case-control studies comprising 1,048 patients with iNPH and 79,668 cognitively unimpaired controls were included in the meta-analysis. Our data showed that hypertension (N = 991, OR = 2.30, 95% CI 1.64 to 3.23, I2= 64.0%), diabetes mellitus (DM) (N = 985, OR = 3.12, 95% CI 2.29 to 4.27, I2= 44.0%), coronary heart disease (CHD; N = 880, OR = 2.34, 95% CI 1.33 to 4.12, I2= 83.1%), and peripheral vascular disease (N = 172, OR = 2.77, 95% CI 1.50 to 5.13, I2= 0.0%) increased the risk for iNPH, while overweight was a possible factor (N = 225, OR = 2.01, 95% CI 1.34 to 3.04, I2= 0.0%) based on the sensitivity analysis. Smoking and alcohol consumption were not associated with iNPH.

Conclusions

Our study suggested that hypertension, DM, CHD, peripheral vascular disease, and overweight were associated with iNPH. These factors might be involved in the pathophysiological mechanisms promoting iNPH. These findings require further investigation in future studies.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, CRD42022383004.

MDS-UDPRS-III in the diagnosis of idiopathic Normal Pressure Hydrocephalus and identification of candidates for Ventriculo-Peritoneal Shunting surgery. Results from a retrospective large cohort of patients

OBJECTIVES

To evaluate the entity of extrapyramidal signs, characterize them and evaluate the dynamics of change by the mean of MDS-UPDRS-III in iNPH patients after the TT to determine if this tool may help the diagnosis of iNPH and the identification of candidates for Ventriculo-Peritoneal Shunting.

MATERIALS AND METHODS

We retrospectively collected data from 120 patients with the initial diagnosis of possible iNPH; they underwent neurological examination by the means of MDS-UPDRS-III and other scales before and after Tap Test (TT). They were then classified as defined iNPH (57), probable iNPH (35), and NOT-iNPH (28) based on the clinical response after the Tap Test and VPS.

RESULTS

After the Tap Test, defined and probable iNPH groups improved by 3.35 (2.57-4.12, p < 0.001) and 3.43 (2.43-4.4, p < 0.001) points on MDS-UPDRS-III respectively; NOT-iNPH did not improve significantly on MDS-UPDRS-III and on any other variable studies. Defined iNPH also shifted significantly from asymmetric prevalence of symptoms to a more symmetric form (from 70% before to 57% after).

CONCLUSION

extrapyramidal signs improved significantly after the Tap Test in definite and probable iNPH patients. MDS-UPDRS-III may be a useful complementary tool in the diagnosis of iNPH and identification of candidates for Ventriculo-Peritoneal Shunting.

Clinical Outcomes After Ventriculo-Peritoneal Shunting in Patients With Classic vs. Complex NPH

Objective

Normal pressure hydrocephalus (NPH) is a neurological condition characterized by a clinical triad of gait disturbance, cognitive impairment, and urinary incontinence in conjunction with ventriculomegaly. Other neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and vascular dementia share some overlapping clinical features. However, there is evidence that patients with comorbid NPH and Alzheimer's or Parkinson's disease may still exhibit good clinical response after CSF diversion. This study aims to evaluate clinical responses after ventriculo-peritoneal shunt (VPS) in a cohort of patients with coexisting NPH and neurodegenerative disease.

Methods

The study has two components; (i) a pilot study was performed that specifically focused upon patients with Complex NPH and following the inclusion of the Complex NPH subtype into consideration for the clinical NPH programme, (ii) a retrospective snapshot study was performed to confirm and characterize differences between Classic and Complex NPH patients being seen consecutively over the course of 1 year within a working subspecialist NPH clinic. We studied the characteristics of patients with Complex NPH, utilizing clinical risk stratification and multimodal biomarkers.

Results

There was no significant difference between responders and non-responders to CSF diversion on comorbidity scales. After VPS insertion, significantly more Classic NPH patients had improved cognition compared to Complex NPH patients (p = 0.005). Improvement in gait and urinary symptoms did not differ between the groups. 26% of the Classic NPH group showed global improvement of the triad, and 42% improved in two domains. Although only 8% showed global improvement of the triad, all Complex NPH patients improved in gait.

Conclusions

Our study has demonstrated that the presence of neurodegenerative disorders co-existing with NPH should not be the sole barrier to the consideration of high-volume tap test or lumbar drainage via a specialist NPH programme. Further characterization of distinct cohorts of NPH with differing degrees of CSF responsiveness due to overlay from neurodegenerative or comorbidity risk burden may aid toward more precise prognostication and treatment strategies. We propose a simplistic conceptual framework to describe NPH by its Classic vs. Complex subtypes to promote the clinical paradigm shift toward subspecialist geriatric neurosurgery by addressing needs for rapid screening tools at the clinical-research interface.

Motor skills, cognitive impairment, and quality of life in normal pressure hydrocephalus: early effects of shunt placement

Background

Traditionally, clinical findings of normal pressure hydrocephalus are mainly characterized by the Hakim triad. The aim of this study is to evaluate the performance of patients suffering from idiopathic normal pressure hydrocephalus (iNPH) in a more holistic manner regarding motor skills, cognitive impairment, and quality of life.

Methods

In total, 30 individuals diagnosed with iNPH as well as a reference group with another 30 individuals were included. The iNPH patients and the reference group were age, educational, and morbidity matched. A standardized test battery for psychomotor skills, gait, neuropsychological abilities as well as questionnaires for quality of life was applied. The iNPH group was tested prior to surgery, at 6 weeks, and 3 months postoperatively. The reference group was tested once.

Results

Patients showed a significant improved performance in various items of the test battery during the first 3 months postoperatively. This included neuropsychological evaluation, motor skills including gait and upper motor function as well as the quality of life of the patients. Compared to reference individuals, neuropsychological aspects and quality of life of iNPH patients improved in some parts nearly to normal values.

Conclusion

Our findings underline that shunt surgery does not only improve the symptoms in iNPH patients but also ameliorates the quality of life to a great extent close to those of age and comorbidity matched reference individuals. This data enables an optimized counseling of iNPH patients regarding the expectable outcome after shunt surgery especially regarding cognitive performance, motor skills as well as life quality.

How should we treat long-standing overt ventriculomegaly in adults (LOVA)? A retrospective cohort study

Long-standing overt ventriculomegaly in adults (LOVA) is a heterogenous group of conditions with differing presentations. Few studies have evaluated success rates of available surgical treatments, or ascertained the natural history. There is a need to assess the efficacy of both endoscopic third ventriculostomy (ETV) and ventriculoperitoneal shunt (VPS) as first-line treatments. We conducted a retrospective, single-centre study of adults with LOVA at a tertiary neurosurgery centre in England, UK, aiming to identify presentation, management strategy, and outcome following treatment. A total of 127 patients were included (mean age 48.1 years, 61/127 male). Most patients were symptomatic (73.2%, n = 93/127, median symptom duration 10 months). The most common symptoms were gait ataxia, headache, and cognitive decline (52.8%, 50.4%, and 33.9%, respectively). Fourteen patients had papilloedema. Ninety-one patients (71.7%) underwent surgery (84 ETV, 7 VPS). Over a median follow-up of 33.0 months (interquartile range [IQR] 19.0-65.7), 82.4% had a clinical improvement after surgery, and 81.3% had radiological improvement. Clinical improvement rates were similar between ETV and VP shunt groups (82.1% vs 85.7%, p = 0.812). Surgical complication rates were significantly lower in the ETV group than the VP shunt group (4.8% vs 42.9%, p < 0.001). Of the patients treated surgically, 20 (22.0%) underwent further surgery, with 14 patients improving. This study demonstrates the efficacy of ETV as a first-line treatment for LOVA.

Outcomes of Ventriculoperitoneal Shunt in Patients With Idiopathic Normal-Pressure Hydrocephalus 2 Years After Surgery

Objective: To evaluate the outcomes and prognostic factors of ventriculoperitoneal shunts (VP-shunts) in patients with idiopathic normal-pressure hydrocephalus (iNPH) at 6 months and 2 years after surgery.

Method: We retrospectively analyzed 68 patients admitted to our institute and diagnosed with probable iNPH from January 2017 to March 2021. All patients underwent VP-shunt surgery with a programmable valve, and their outcomes were assessed via the Krauss index and modified Rankin scale (mRS) at 6 months and 2 years post-surgery. Univariate and multivariate regression analysis was performed to identify the prognostic factors.

Results: The mean age of the patients was 71.1 ± 8.4 (mean ± standard deviation) years. On the Krauss improvement index, 6-month follow-up results were available for 68 patients. Of these patients, 91.2% experienced attenuation of their preoperative symptoms, with a mean Krauss index of 0.58 ± 0.27, and 48 patients (70.6%) had a Krauss index ≥0.5. Two-year follow-up results were available for 33 patients; 90.9% of them had sustained improvement, with a Krauss index of 0.54 ± 0.31, and 21 patients (66.3%) had a Krauss index ≥0.5. Thirty-three patients (58%) were living independently after 2 years (mRS 0–2). The outcomes were worse for patients with multiple comorbidities. Neither an increased patient age nor a prolonged history of illness was statistically significant prognostic factors for adverse outcomes of VP-shunt surgery.

Conclusion: Surgical treatment was well-tolerated by patients with iNPH who received VP-shunts. Most patients experienced attenuation of their preoperative symptoms. Multiple concurrent comorbidities should be considered as adverse prognostic factors before shunt insertion in patients with iNPH.

The Role of Machine Learning and Radiomics for Treatment Response Prediction in Idiopathic Normal Pressure Hydrocephalus

Introduction Ventricular shunting remains the standard of care for patients with idiopathic normal pressure hydrocephalus (iNPH); however, not all patients benefit from the shunting. Prediction of response in advance can result in improved patient selection for ventricular shunting. This study aims to develop a machine learning predictive model for treatment response after shunt placement using the clinical and radiomics features. Methods In this retrospective pilot study, the medical records of iNPH patients who underwent ventricular shunting were evaluated. In each patient, the "idiopathic normal pressure hydrocephalus grading scale" (iNPHGS) and a "Modified Rankin Scale" were calculated before and after surgery. The subsequent treatment response was calculated as the difference between the iNPHGS scores before and after surgery. iNPHGS score reduction of two or more than two were considered as treatment response. The presurgical MRI scans were evaluated by radiologists, the ventricular systems were segmented on the T2-weighted images, and the radiomics features were extracted from the segmented ventricular system. Using Orange data mining open-source platform, different machine learning models were then developed based on the presurgical clinical features and the selected radiomics features to predict treatment response after shunt placement. Results After the implementation of the inclusion criteria, 78 patients were included in this study. One hundred twenty radiomics features were extracted, and the 12 best predictive radiomics features were selected. Using only clinical data (iNPHGS and Modified Rankin Scale), the random forest model achieved the best performance in treatment prediction with an area under the curve (AUC) of 0.71. Adding the Radiomics analysis to the clinical data improved the prediction performance, with the support vector machine (SVM) achieving the highest rank in treatment prediction with an AUC of 0.8. Adding age and sex to the analysis did not improve the prediction. Conclusion Using machine learning models for treatment response prediction in patients with iNPH is feasible with acceptable accuracy. Adding the Radiomics analysis to the clinical features can further improve the predictive performance. SVM is likely the best model for this task.

The Role of Simultaneous Medical Conditions in Idiopathic Normal Pressure Hydrocephalus

BACKGROUND

Idiopathic normal pressure hydrocephalus (iNPH) is a chronic neurologic syndrome that affects the elderly population in a context of concomitant medical conditions. The aim of this study was to understand the significance of comorbidities using 4 validated and specific clinical scores: Cumulative Illness Rating Scale (CIRS), American Society of Anesthesiologists (ASA) score, Comorbidity Index (CMI), and Charlson Comorbidity Index (CCI).

METHODS

From 2015 until 2019, the Bologna PRO-Hydro multidisciplinary team selected 63 patients for shunt surgery. All comorbidity scores were collected during preoperative anesthesia evaluation. Positive shunt response was defined as an improvement in overall disability (assessed with modified Rankin Scale [mRS]), in risk of fall (assessed with Tinetti Permormance Orientated Mobility Assessment, Tinetti) and in INPH specific symptoms (assessed with INPH Grading Scale, INPHGS).

RESULTS

Patients with elevated values of CIRS had worse performance in gait and balance at Tinetti scale, both before (P = 0.039) and after surgery (P = 0.005); patients with high values of CMI had inferior values of Tinetti at baseline (P = 0.027) and higher mRS after surgery (P = 0.009); ASA 2 patients had better postoperative Tinetti scores than ASA 3 patients (P = 0.027). A positive or negative shunt response was not significantly correlated with patients' preoperative comorbidity scores.

CONCLUSIONS

Patients with multiple comorbidities have a worse preoperative condition compared to patients with less concomitant diseases, and the proposed comorbidity scores, CIRS in particular, are useful clinical tools for the anesthesiologist. Comorbidities, though, do not impact overall postoperative outcome.

Prognostic value of the pulse pressure amplitudes, time to reach the plateau and the slope obtained in the lumbar infusion test for the study of idiophatic normal pressure hydrocephalus

BACKGROUND AND OBJECTIVE

To study the prognostic value of the resistance to the cerebrospinal fluid outflow (Rout) obtained in the lumbar infusion test in idiopathic normal pressure hydrocephalus (iNPH), as well as the pulse pressure amplitudes in the different periods of the test and other new variables extracted by Neuropicture® software.

MATERIAL AND METHODS

Patients with 'probable iNPH' who underwent a lumbar infusion test were retrospectively revised. The positive predictive values (PPV) of the cutoff point of the best prognostic accuracy of the Rout, the basal pulse pressure amplitude (AMPo), the pulse pressure amplitude during the first 10 min (AMP_10min), the plateau pulse pressure amplitude (AMPmes), the Rout pulse pressure amplitude (AMP_Rout), the time to reach the plateau (T), and the slope until reaching the plateau were determined. Patients were categorized either as responders or non-responders.

RESULTS

The study included 64 responders patients and 16 non-responders patients. The PPV of Rout > 15 mmHg/mL/min was 91.7%; AMPo > 2.34 mmHg: 91.3%; AMP_{10 min} > 4.34 mmHg: 83.3%; AMPmes > 12.44 mmHg: 84.6%; AMP_Rout > 6.34 mmHg: 85%; T < 634 s: 86.7%; p > 0.040 mmHg/s: 96.3%.

CONCLUSIONS

Rout is a valid criterion to indicate a ventricular shunt. Pulse pressure amplitudes in the different periods of the lumbar infusion test, in addition to T and P, are other variables whose positivity is indicative of shunt response and should be considered in the diagnostic protocol of the iNPH.

The role of amyloid PET in patient selection for extra-ventricular shunt insertion for the treatment of idiopathic normal pressure hydrocephalus: A pooled analysis

BACKGROUND

Idiopathic Normal Pressure Hydrocephalus (iNPH) can be effectively treated through shunt insertion. However, most shunted patients experience little or no clinical benefit, which suggests suboptimal patient selection. While contentious, multiple studies have reported poorer shunt outcomes associated with concomitant Alzheimer's disease. Prompted by this observation, multiple studies have assessed the role of amyloid PET, a specific test for Alzheimer's disease, in patient selection for shunting.

METHODS

A comprehensive literature search was performed to identify studies that assessed the association between amyloid PET result and the clinical response to shunting in patients with suspected iNPH. Pooled diagnostic statistics were calculated.

RESULTS

Across three relevant studies, a total of 38 patients with suspected iNPH underwent amyloid PET imaging and shunt insertion. Twenty-three patients had a positive clinical response to shunting. 18/28 (64.3%) of patients with a negative amyloid PET and 5/10 (50%) with a positive amyloid PET had a positive response to shunting. The pooled sensitivity, specificity and accuracy was 33.3%, 76.2% and 58.3%. None of these statistics reached statistical significance.

CONCLUSION

The results of this pooled analysis do not support the selection of patients with suspected iNPH for shunting on the basis of amyloid PET alone. However, due to small cohort sizes and weakness in study design, further high-quality studies are required to properly determine the role of amyloid PET in assessing this complex patient group.

Preoperative Predictive Factors of Short-Term Outcome in Idiopathic Normal Pressure Hydrocephalus

BACKGROUND

Surgical treatment of idiopathic normal pressure hydrocephalus (iNPH) by ventriculoperitoneal (VP) or lumboperitoneal (LP) shunting can achieve long-term recovery of activities of daily living; however, in a subset of patients, maintenance of independence lasted for <6 months. This study examined positive preoperative predictive factors of short-term outcome for shunted iNPH patients.

METHODS

Over a 9-year period, consecutive patients from multiple centers diagnosed with probable iNPH underwent either VP or LP shunt surgery. Preoperative variables of age, symptom duration, iNPH severity, tap test response, and magnetic resonance imaging findings of disproportionately enlarged subarachnoid space hydrocephalus (DESH) or incomplete DESH were retrospectively evaluated in relation to 1-year postoperative outcome.

RESULTS

Outcome for 154 shunt patients (12 VP, 142 LP) as measured by postoperative disability modified Rankin Scale (mRS) and iNPH-gait disturbance (GD) was the same regardless of age. Symptom duration was inversely correlated with both iNPH severity (P < 0.0001) and postoperative improvement at 1 year (P = 0.0015). Severity also correlated inversely with postoperative improvement at 1 year (P < 0.0001). Age was not significantly correlated with the degree of postoperative improvement (mRS: P = 0.487; iNPH grading scale [GD]: P = 0.725). Outcome at 1 year (mRS, gait domain, and activities of daily living significantly improved in patients with a good response to the tap test (P < 0.0001) Preoperative DESH correlated with improvement in mRS and GD (P < 0.0001).

CONCLUSIONS

Mild preoperative iNPH severity, shorter preoperative symptom duration, good tap test response, and complete DESH were associated with good short-term postoperative outcome at 1 year. These positive factors may be useful for prediction of short-term surgical outcome in iNPH patients.

Prognostic value of the pulse pressure amplitudes, time to reach the plateau and the slope obtained in the lumbar infusion test for the study of idiophatic normal pressure hydrocephalus

BACKGROUND AND OBJECTIVE

To study the prognostic value of the resistance to the cerebrospinal fluid outflow (Rout) obtained in the lumbar infusion test in idiopathic normal pressure hydrocephalus (iNPH), as well as the pulse pressure amplitudes in the different periods of the test and other new variables extracted by Neuropicture® software.

MATERIAL AND METHODS

Patients with ́probable iNPH́ who underwent a lumbar infusion test were retrospectively revised. The positive predictive values (PPV) of the cutoff point of the best prognostic accuracy of the Rout, the basal pulse pressure amplitude (AMP0), the pulse pressure amplitude during the first 10minutes (AMP10min), the plateau pulse pressure amplitude (AMPmes), the Rout pulse pressure amplitude (AMPRout), the time to reach the plateau (T), and the slope until reaching the plateau were determined. Patients were categorized either as responders or non-responders.

RESULTS

The study included 64 responders patients and 16 non-responders patients. The PPV of Rout> 15mmHg/ml/min was 91.7%; AMP0> 2.34mmHg: 91.3%; AMP10min>4.34mmHg: 83.3%; AMPmes>12.44mmHg: 84.6%; AMPRout>6.34mmHg: 85%; T <634seconds: 86.7%; P>0.040mmHg/sec: 96.3%.

CONCLUSIONS

Rout is a valid criterion to indicate a ventricular shunt. Pulse pressure amplitudes in the different periods of the lumbar infusion test, in addition to T and P, are other variables whose positivity is indicative of shunt response and should be considered in the diagnostic protocol of the iNPH.

Impact of Comorbidities and Frailty on Early Shunt Failure in Geriatric Patients With Normal Pressure Hydrocephalus

Background/Aim: Older patients are considered to bear a higher perioperative risk. Since idiopathic normal pressure hydrocephalus (NPH) predominantly concerns older patients, identifying risk factors for early shunt failure for preoperative risk/benefit assessment is indispensable for indication and/or consultation of patients for ventriculoperitoneal shunting (VPS).

Methods: We performed a retrospective study design, including data acquired from two university hospital neurosurgical institutions between 2012 and 2019. Overall, 211 consecutive patients with clinical/radiological signs for NPH who additionally showed alleviation of symptoms after lumbar cerebrospinal fluid (CSF) drainage, received VPS and were included for further analysis. Frailty was measured using the Clinical Frailty Scale (CFS). Main outcome was early shunt failure or post-operative complications within 30 days after initial VPS surgery.

Results: The overall complication rate was 14%. Patient-related complications were observed in 13 patients (6%) and procedure-related complications in 16 patients (8%). Early post-operative complications resulted in a significantly prolonged length of hospital stay 6.9 ± 6.8 vs. 10.8 ± 11.8 days (p = 0.03). Diabetes mellitus with end-organ damage (OR 35.4, 95% CI 6.6 – 189.4, p < 0.0001) as well as preexisting Parkinson's disease were associated with early patient-related post-surgical complications after VPS for NPH.

Conclusions: Patients comorbidities but not frailty were associated with early post-operative patient-related complications in patients suffering NPH. While frailty may deter patients from other (neurosurgical) procedures, VPS surgery might contribute to treating NPH in these patients at a tolerable risk.

Role of psychiatric, cardiovascular, socioeconomic, and demographic risk factors on idiopathic normal pressure hydrocephalus: A retrospective case-control study

OBJECTIVES

Currently, predicting and preventing idiopathic normal pressure hydrocephalus (iNPH) remains challenging, especially for patients without a history of cerebrovascular disease. By exploring the role of cardiovascular and psychiatric history, demographics, and socioeconomic status in iNPH, will provide better direction for elucidating the etiology or addressing healthcare inequalities.

PATIENTS AND METHODS

To investigate iNPH with respect to the selected risk factors, we conducted a retrospective case-control study from a neuroscience institute in Hawaii with a patient pool of 25,843. After excluding patients with a history of cerebrovascular disease, we identified 29 cases which meet the American-European guidelines for iNPH diagnosis. Meanwhile, 116 controls matched to age, sex, and race were also randomly selected.

RESULTS

Median age at diagnosis was 83 (IQR: 74-88), with cases estimated 22 years older than controls (95 % CI: 14.00-29.00; p = 0.0000001). Patients with iNPH were more likely to be White (OR 4.01, 95 % CI: 1.59-10.11; p = 0.0042) and less likely Native Hawaiian and other Pacific Islander (OR 0.010, 95 % CI: 0.00-0.78; p = 0.014). Median household income was $2874 (95 % CI: 0.000089-6905; p = 0.088) greater amongst iNPH cases. Effect size amongst cardiovascular risk factors was not found statistically significant (i.e., body mass index, hyperlipidemia, type 2 diabetes mellitus, hypertension, coronary artery disease or prior myocardial infarction history, peripheral vascular disease, smoking status, congestive heart failure, atrial fibrillation/flutter, and history of prosthetic valve replacement). However, iNPH patients were more likely to have a history of alcohol use disorder (OR 8.29, 95 % CI: 0.99-453.87; p = 0.050) and history of a psychiatric disorder (OR 2.48; 95 % CI: 1.08-5.68; p = 0.029). Odds ratio for autoimmune disorder, thyroid disorder, glaucoma, and seizures did not reach statistical significance.

CONCLUSION

Patient race (i.e., White; Native Hawaiian or other Pacific Islander) was found associated with iNPH development. Meanwhile, after excluding those with cerebrovascular disease, cardiovascular risk factors were not found associated with iNPH. Lastly, iNPH cases were more inclined to have a history of alcohol use disorder and prior psychiatric disorder. Overall, this data reveals that a racial disparity exists amongst iNPH, as well as highlights the role of various cardiovascular and psychiatric risk factors, which can potentially provide direction in etiology elucidation.

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

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.

Negative predictors of shunt surgery outcome in normal pressure hydrocephalus

OBJECTIVES

The prevalence of idiopathic normal pressure hydrocephalus (iNPH) and vascular comorbidity increases with age. It has not been clarified if high age and vascular disease are negative predictors of shunt surgery outcome in patients with iNPH. The aim of this study was to investigate the impact of high age and vascular comorbidity on outcome after shunt surgery in patients with iNPH.

METHODS

All 332 patients with iNPH who were treated with shunts between 2011 and 2015 at a single centre were consecutively included. Hellström iNPH scale, without the neuropsychological tests, was calculated preoperatively and at follow-up 12 months after shunt surgery. Outcome was defined as the difference between the post-operative and preoperative iNPH scale scores. A multivariable model was used to investigate the predictive effects of age and vascular comorbidity on shunt surgery outcome.

RESULTS

In a multivariable analysis of covariance (ANCOVA) with post-operative outcome as the dependent variable, increasing age (years, B = -0.63, P < .001) and history of ischaemic stroke (B = -10.06, P = .0038) were negative predictors of shunt surgery outcome after controlling for waiting time for surgery, symptom severity at preoperative control, presence of diabetes mellitus, hypertension, hyperlipidaemia, history of myocardial infarction, duration of symptoms and shunt complications.

CONCLUSIONS

High age and established cerebrovascular disease are associated with less favourable outcome after shunt surgery in patients with iNPH.

Preoperative biomarkers in patients with idiopathic normal pressure hydrocephalus showing a favorable shunt surgery outcome

INTRODUCTION

Idiopathic normal pressure hydrocephalus (INPH) is known to be a potentially treatable neurologic condition. The neurocognitive outcomes after surgery, however, have been variable. It is important to define preoperative characteristics of patients that predicts the shunting outcome. We aimed to compare baseline differences between shunt-responsive and unresponsive patients after 1year from surgery in order to identify preoperative predictors showing favorable clinical outcomes.

METHODS

Among 69 candidates, 31 patients with probable INPH completed the study. Patients were divided into two groups, responsive group (n=17) and unresponsive group (n=14), according to the clinical outcomes on INPH grading scale and modified Rankin score (MRS). Preoperative cerebrospinal (CSF) Aß, tau levels, MRI findings, and clinical characteristics were compared between the groups. Correlations between shunt responsiveness and preoperative characteristics were also assessed.

RESULTS

After 1year from shunt, gait problem was the most likely to improve. Shunt-responsive group showed lower CSF p-tau/Aß, fewer lacunes, and higher incidence of disproportionately enlarged subarachnoid space (DESH) signs on MRIs compared to those in unresponsive group. Favorable outcome was related with positive DESH sign and fewer lacunes.

CONCLUSIONS

Our results suggest that biomarkers representing non-INPH related pathology including Alzheimer's disease and small vessel disease might show less favorable clinical outcomes after 1year from surgery.

Alzheimer's disease pathology and shunt surgery outcome in normal pressure hydrocephalus

We aimed to determine whether presence of AD neuropathology predicted cognitive, gait and balance measures in patients with idiopathic normal pressure hydrocephalus (iNPH) after shunt surgery. This is a prospective study of gait and balance measured by Timed Up and Go (TUG) and Tinetti tests, and cognitive function measured by Mini Mental Status Exam (MMSE), before and after shunt surgery in participants 65 years and older with iNPH at the Johns Hopkins University. Random effects models were used and adjusted for confounders. 88 participants were included in the analysis with a median (IQR) time of 104 (57–213) days between surgery and follow-up. 23 (25%) participants had neuritic plaques present (NP+) and were significantly older [76.4 (6.0) years], but were otherwise similar in all demographics and outcome measures, when compared to the group without neuritic plaques (NP-). NP- and NP+ participants equally improved on measures of TUG (β = -3.27, 95% CI -6.24, -0.30, p = 0.03; β = -2.37, 95% CI -3.90, -0.86, p = 0.02, respectively), Tinetti-total (β = 1.95, 95% CI 1.11, 2.78, p<0.001; β = 1.72, 95% CI 0.90, 2.53, p<0.001, respectively), -balance (β = 0.81, 95% CI 0.23, 1.38, p = 0.006; β = 0.87, 95% CI 0.40, 1.34, p<0.001, respectively) and -gait (β = 1.03, 95% CI 0.61, 1.45, p<0.001; β = 0.84, 95% CI 0.16, 1.53, p = 0.02, respectively), while neither NP- nor NP+ showed significant improvement on MMSE (β = 0.10, 95% CI -0.27, 0.46, p = 0.61, β = 0.41, 95% CI -0.27, 1.09, p = 0.24, respectively). In summary, 26% of participants with iNPH had coexisting AD pathology, which does not significantly influence the clinical response to shunt surgery.

Revisiting secondary normal pressure hydrocephalus: does it exist? A review

OBJECTIVE There are several etiologies that can lead to the development of secondary normal pressure hydrocephalus (sNPH). The aim of this study was to evaluate the etiology, diagnosis, treatment, and outcome in patients with sNPH and to highlight important differences between the separate etiologies. METHODS A comprehensive review of the literature was performed to identify studies conducted between 1965 and 2015 that included data regarding the etiology, treatment, diagnosis, and outcome in patients with sNPH. Sixty-four studies with a total of 1309 patients were included. The inclusion criteria of this study were articles that were written in English, included more than 2 patients with the diagnosis of sNPH, and contained data regarding the etiology, diagnosis, treatment, or outcome of NPH. The most common assessment of clinical improvement was based on the Stein and Langfitt grading scale or equivalent improvement on other alternative ordinal grading scales. RESULTS The main etiologies of sNPH were subarachnoid hemorrhage (SAH) in 46.5%, head trauma in 29%, intracranial malignancies in 6.2%, meningoencephalitis in 5%, and cerebrovascular disease in 4.5% of patients. In 71.9% of patients the sNPH was treated with ventriculoperitoneal shunt placement, and 24.4% had placement of a ventriculoatrial shunt. Clinical improvement after shunt placement was reported in 74.4% and excellent clinical improvement in 58% of patients with sNPH. The mean follow-up period after shunt placement was 13 months. Improvement was seen in 84.2% of patients with SAH, 83% of patients with head trauma, 86.4% of patients with brain tumors, 75% of patients with meningoencephalitis, and 64.7% of patients with NPH secondary to stroke. CONCLUSIONS Secondary NPH encompasses a diverse group of clinical manifestations associated with a subset of patients with acquired hydrocephalus. The most common etiologies of sNPH include SAH and traumatic brain injury. Secondary NPH does indeed exist, and should be differentiated from idiopathic NPH based on outcome and on clinical, pathophysiological, and epidemiological characteristics, but should not be considered as a separate entity.

Practice guideline: Idiopathic normal pressure hydrocephalus: Response to shunting and predictors of response: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology

OBJECTIVE

We evaluated evidence for utility of shunting in idiopathic normal pressure hydrocephalus (iNPH) and for predictors of shunting effectiveness.

METHODS

We identified and classified relevant published studies according to 2004 and 2011 American Academy of Neurology methodology.

RESULTS

Of 21 articles, we identified 3 Class I articles.

CONCLUSIONS

Shunting is possibly effective in iNPH (96% chance subjective improvement, 83% chance improvement on timed walk test at 6 months) (3 Class III). Serious adverse event risk was 11% (1 Class III). Predictors of success included elevated Ro (1 Class I, multiple Class II), impaired cerebral blood flow reactivity to acetazolamide (by SPECT) (1 Class I), and positive response to either external lumbar drainage (1 Class III) or repeated lumbar punctures. Age may not be a prognostic factor (1 Class II). Data are insufficient to judge efficacy of radionuclide cisternography or aqueductal flow measurement by MRI.

RECOMMENDATIONS

Clinicians may choose to offer shunting for subjective iNPH symptoms and gait (Level C). Because of significant adverse event risk, risks and benefits should be carefully weighed (Level B). Clinicians should inform patients with iNPH with elevated Ro and their families that they have an increased chance of responding to shunting compared with those without such elevation (Level B). Clinicians may counsel patients with iNPH and their families that (1) positive response to external lumbar drainage or to repeated lumbar punctures increases the chance of response to shunting, and (2) increasing age does not decrease the chance of shunting being successful (both Level C).

Comparison of outcomes between patients with idiopathic normal pressure hydrocephalus who received a primary versus a salvage shunt

Placement of a ventriculoperitoneal (VP) shunt is the treatment of choice for communicating hydrocephalus; however, the extent to which VP shunting is able to relieve symptoms in patients who had previously been treated with cerebrospinal fluid diverting therapy at an outside institution remains unclear. A retrospective review of patients with idiopathic normal pressure hydrocephalus treated with VP shunts at a single institution between 1993 and 2013 was conducted. Patients were classified as having received a primary VP shunt if they had not been previously treated with a VP shunt, ventriculoatrial shunt, lumboperitoneal shunt, or endoscopic third ventriculostomy. Patients were classified as having received a salvage VP shunt if they had been previously treated by one of these four modalities at an outside institution prior to their presentation to our institution. There were 357 patients who received a primary shunt and 33 patients who received a salvage shunt. Patients who had a salvage shunt placed had significantly higher odds of requiring a future revision (54% versus 41%; odds ratio=2.85; 95% confidence interval [CI]: 1.24-6.57; p=0.014). Patients who received a salvage shunt had statistically significantly lower rates of gait improvement at 6months in comparison to patients who received a primary shunt (relative risk=0.35; 95% CI: 0.14-0.87; p=0.025). Despite these findings, there was no significant difference at last follow-up in improvement in gait, continence, and cognition, indicating that outcomes for patients requiring a salvage shunt were comparable to patients receiving a primary shunt.

Outcome of modern shunt therapy in patients with idiopathic normal pressure hydrocephalus 6 years postoperatively

Object

Shunt therapy in idiopathic normal pressure hydrocephalus (iNPH) can improve symptoms in 84% of patients 1 year postoperatively. Therefore, implantation of a ventriculoperitoneal shunt (VPS) prevents or at least prolongs the time during which patients are not dependent on care from others because of gait disorder or dementia. In this study, the medium-term results of modern shunt therapy were evaluated.

Methods

The authors retrospectively studied outcome in iNPH patients in whom VPSs were implanted. At yearly follow-up examinations over at least 6 years, clinical symptoms were recorded according to the NPH recovery rate (NPH-RR): (preoperative Kiefer Scale [KS] score − postoperative KS score)/(preoperative KS score × 10). Time and cause of death over this period were also analyzed.

Results

Among the 147 patients treated for iNPH in the period between 1997 and 2006, 69 had died at the time of the authors' survey. Sixty-one patients reached the 6-year examination. The median age was 64 years (range 33–83 years) at the time of VPS implantation and 73 years (range 41–91 years) at the time of this study. Six years after shunt implantation, the median KS score was significantly lower than the preoperative score (4.3 vs 8.1 points). Fifty-nine percent of 61 patients had an excellent outcome, 15% had satisfactory benefit, and 26% had unsatisfactory results 6 years postoperatively. Three of the 147 patients who underwent implantation of a VPS died of cerebral diseases 4–10 years postoperatively.

Conclusions

Implantation of a VPS is a safe procedure and can improve symptoms in 74% of patients with iNPH in the longer term.

Predictors of subsequent overdrainage and clinical outcomes after ventriculoperitoneal shunting for idiopathic normal pressure hydrocephalus

BACKGROUND

Little is known about variables associated with overdrainage complications and neurofunctional and health-related quality of life outcomes in idiopathic normal-pressure hydrocephalus (iNPH) patients after shunt surgery.

OBJECTIVE

To identify candidate demographic and disease-specific predictors of overdrainage and patient-related outcomes, allowing for more personalized care of patients with iNPH.

METHODS

This was a secondary analysis of the dataset of the SVASONA study, a multicenter randomized trial comparing gravitational and conventional gravitational valves for treating iNPH. We evaluated the association between baseline items and the incidence of overdrainage, using different endpoint definitions.

RESULTS

We identified only a few variables associated with a possible increased risk of overdrainage. Apart from using conventional rather than gravitational valves, longer duration of surgery and female sex were associated with a higher risk of clinical signs and symptoms suggestive of overdrainage (hazard ratio: 1.02, 95% confidence interval: 1.01-1.04 and 1.84, 95% confidence interval: 0.81-4.16). The occurrence of clinical symptoms of overdrainage, and the need for exchanging a programmable by a gravitational valve may adversely affect disease-specific outcomes like the Kiefer score.

CONCLUSION

Few, if any, baseline and treatment characteristics may be helpful in estimating the individual risk of complications and clinical outcomes after shunt surgery for iNPH. Patients should be informed that longer surgery for any reason may increase the risk of later overdrainage. Also, women should be counseled about a sex-associated increased risk of the development of clinical symptoms of overdrainage, although the latter cannot be distinguished from a generally higher prevalence of headaches in the female population.

Normal pressure hydrocephalus: a qualitative study on outcome

OBJECTIVE

To describe the natural history and shunt outcome in patients with normal pressure hydrocephalus (NPH) and the variables that influence both.

METHOD

Motor and cognitive parameters of 35 patients with NPH, as well as shunt surgery status, were registered at two time points (T0 and T1).

RESULTS

Thirteen patients underwent shunt surgery. Favorable outcome in gait function occurred in 5 of 35 patients and was related to younger age, absence of cardiovascular risk factors (CVRF) and white matter lesions (WML), and shunt surgery. Cognitive outcome was favorable in 9 of 35 patients and associated with shunt surgery (trend level). Of the patients subjected to surgery, favorable outcome in motor function was related to younger age at T0 and absence of CVRF and WML (trend level).

CONCLUSION

Shunt surgery had a significant effect on gait and less on cognition. Favorable outcome in gait was also associated with younger age and absence of CVRF and WML.

Systematic review of the outcome of shunt surgery in idiopathic normal-pressure hydrocephalus

INTRODUCTION

Early surgical series of shunt insertion for idiopathic normal-pressure hydrocephalus reported a low rate of short-term improvement with a relatively high rate of mortality and morbidity; subsequently shunt insertion was recommended for patients in whom there is favourable risk-to-benefit ratio.

METHODS

Bibliographic search for studies that objectively assessed the outcome following shunt insertion in idiopathic normal-pressure hydrocephalus was done; the aim was to estimate the outcome of shunt insertion in terms of improvement rates and associated mortality and morbidity.

RESULTS

A total of 64 studies of 3,063 patients were reviewed. Positive improvement following shunt insertion was reported in an average of 71 % of patients with an average 1 % mortality. Results from studies published in the last 5 years showed 82 % improvement following shunt insertion, mortality of 0.2 %, and combined common complications rate of 8.2 %.

CONCLUSION

When patients are properly selected, shunt insertion is a safe and effective management of idiopathic normal-pressure hydrocephalus with a prolonged positive outcome.

The differential diagnosis and treatment of normal-pressure hydrocephalus

BACKGROUND

Normal-pressure hydrocephalus (NPH) arises in adulthood and is characterized by a typical combination of clinical and radiological findings. The mean basal intracranial pressure is normal or mildly elevated. The typical signs of the disease are gait impairment, urinary incontinence, and dementia. The difficulty of distinguishing NPH from other neurodegenerative disorders is the likely reason why some 80% of cases remain unrecognized and untreated. According to current evidence, the spontaneous course of NPH ends, for the vast majority of patients, in dependence on nursing care.

METHODS

This review article is based on relevant publications retrieved by a selective search in Medline and on national and international guidelines for the management of NPH.

RESULTS

Studies with a high evidence level are lacking; thus, the current state of knowledge about NPH is derived from studies of low or intermediate evidence levels, e.g., observational studies. Modern forms of treatment lead to clinical improvement in 70% to 90% of treated patients. The treatment of choice is the implantation of a ventriculoperitoneal shunt. The differential diagnosis is complicated by the fact that three-quarters of patients with NPH severe enough to require treatment also suffer from another neurodegenerative disorder. Therefore, the clinical findings and imaging studies often do not suffice to establish the indication for surgery. To do this, a further, semi-invasive diagnostic procedure is recommended. Current risk/benefit analyses indicate that shunt operations improve outcome compared to the spontaneous course of the disease.

CONCLUSION

Normal pressure hydrocephalus should always enter into the differential diagnosis of patients who present with its characteristic manifestations. If the diagnosis of NPH is confirmed, it should be treated at an early stage.

Selection of patients with idiopathic normal-pressure hydrocephalus for shunt placement: a single-institution experience

OBJECT

The ability to predict outcome after shunt placement in patients with idiopathic normal-pressure hydrocephalus (NPH) represents a challenge. To date, no single diagnostic tool or combination of tools has proved capable of reliably predicting whether the condition of a patient with suspected NPH will improve after a shunting procedure. In this paper, the authors report their experience with 120 patients with the goal of identifying CSF hydrodynamics criteria capable of selecting patients with idiopathic NPH. Specifically, they focused on the comparison between CSF-outflow resistance (R-out) and intracranial elastance (IE).

METHODS

Between January 1977 and December 2005, 120 patients in whom idiopathic NPH had been diagnosed (on the basis of clinical findings and imaging) underwent CSF hydrodynamics evaluation based on an intraventricular infusion test. Ninety-six patients underwent CSF shunt placement: 32 between 1977 and 1989 (Group I) on the basis of purely clinical and radiological criteria; 44 between 1990 and 2002 (Group II) on the basis of the same criteria as Group I and because they had an IE slope > 0.25; and 20 between 2003 and 2005 (Group III) on the basis of the same criteria as Group II but with an IE slope > or = 0.30. Outcomes were evaluated by means of both Stein-Langfitt and Larsson scores. Patients' conditions were considered improved when there was a stable decrease (at 6- and 12-month follow-up) of at least 1 point in the Stein-Langfitt score and 2 points in the Larsson score.

RESULTS

Group I: while no statistically significant difference in mean R-out value between improved and unimproved cases was observed, a clear-cut IE slope value of 0.25 differentiated very sharply between unimproved and improved cases. Group II: R-out values in the 2 unimproved cases were 20 and 47 mm Hg/ml/min, respectively. The mean IE slope in the improved cases was 0.56 (range 0.30-1.4), while the IE slopes in the 2 unimproved cases were 0.26 and 0.27. Group III: the mean IE slope was 0.51 (range 0.31-0.7). The conditions of all patients improved after shunting. A significant reduction of the Evans ratio was observed in 34 (40.5%) of the 84 improved cases and in none of the unimproved cases.

CONCLUSIONS

Our strategy based on the analysis of CSF pulse pressure parameters seems to have a great accuracy in predicting surgical outcome in clinical practice.

Clinical proof of the importance of compliance for hydrocephalus pathophysiology

INTRODUCTION

Recently decreased compliance is discussed as an initially disturbed CSF hydrodynamic parameter in hydrocephalus.

MATERIALS AND METHODS

In 180 patients with suspected chronic hydrocephalus we performed a dynamic infusion test, which was not used for shunt indication. Shunt indication was based on long-term ICP monitoring. Follow-up was 4.6 +/- 1.8 years.

STATISTICS

Spearman-, Kruskal-Wallis-, Wilcoxen-U-test.

RESULTS

Resistance to outflow (Rout) and Pressure Volume Index (PVI) alone provide positive predictive values (PPV) and sensitivity, which might be sufficient in daily practice, while negative predictive values (NPV) and specificity are weak. With an intelligent combined algorithm of Rout and PVI at a critical value of ROF of 13 mm Hg/ml x min and 30 ml, a clearly improved outcome prediction is possible.

CONCLUSION

These clinical results support recent opinions concerning the meaning of Compliance and Rout in hydrocephalus patho-physiology.

Does idiopathic normal pressure hydrocephalus always mean a poor prognosis?

OBJECTIVE

The objective was to assess whether idiopathic normal-pressure hydrocephalus (iNPH) has a worse prognosis than other forms of hydrocephalus, as has been suggested.

METHODS

A total of 125 patients with chronic hydrocephalus, 75 of whom suffered from iNPH and the remaining (non-INPH) from sNPH or non-communicating hydrocephalus, were shunted using gravitational valves. Clinical state was assessed with our clinical grading (KI) and a co-morbidity index (CMI). Average follow-up was 5.1 +/- 1.6 years.

STATISTICS

Spearman, Kruskal-Wallis, ANOVA, chi(2)- and the Wilcoxon U tests at a significance level of pi < 0.05 were used.

RESULTS

Shunt responder rates for iNPH and non-iNPH were 72% and 86%, respectively. With shorter anamnesis (< or =1 year) or preoperative KI < 6 points, iNPH patients had a similar or even better outcome than non-iNPH patients with longer anamnesis or a worse KI. Most impressive was the influence of co-morbidity: 86% of iNPH patients with a low CMI (< or =3 points) experienced clinical improvement after shunting, which was contrasted by a responder rate of 64% for non-iNPH with worse CMI.

CONCLUSION

The diagnosis of iNPH does not by itself mean a worse prognosis, and iNPH patients with favorable preconditions may have a similar or better prognosis than patients with any other kind of hydrocephalus. The worse overall clinical results of iNPH result from late recognition and in most instances worse preconditions.

Gravitational shunt complications after a five-year follow-up

INTRODUCTION

Gravitational shunts (G-valves) for ventriculo-peritoneal (VP) shunting have been available since 1996. We analyzed shunt complications in patients with a complete minimum follow-up of 5 years.

MATERIAL AND METHODS

Between 1996 and 2002, we implanted 282 VP G-valves in various forms of adult chronic hydrocephalus, of which 130 provided a complete data set with an annual follow-up. Adjustable and non-adjustable G-valves were used: the Miethke Dual-Switch valve, the Miethke GAV-valve and a combination of adjustable Codman-Hakim valves with the Miethke Shunt-Assistant. In cases of supposed mechanical shunt failure, the explanted shunts were examined in a bench test.

RESULTS

The total complication rate was 21%:3% shunt infections, 3% catheter dislocation/fracture, 5% underdrainage and 9% overdrainage occurred. Half of the overdrainage complications could be managed conservatively. Underdrainage complications resulted from the chosen opening pressure being too high (n = 3), a secondary increase in intraperitoneal pressure (n = 2) or from "real" shunt failure in one case according to bench test results.

CONCLUSION

G-valves demonstrate sufficient long-term performance over multiple years, and real shunt-related complications are rare. The frequency of revision due to overdrainage is low (4.5%).

An algorithm to assess the rehabilitation potential in patients with chronic hydrocephalus

OBJECTIVE

In clinical practice, it is often necessary to judge the probability of clinical benefit of invasive ancillary tests given to patients with chronic hydrocephalus before they are performed. The aim of the current study was to establish a screening tool for such prediction.

MATERIAL AND METHODS

A total of 125 patients with chronic hydrocephalus were assessed using a clinical (HHS) and comorbidity (CMI) grading. These patients were shunted and followed-up for at least one year. The statistical tools of ANOVA, CHI-squared, Spearman, Kuskal-Wallis, and Wilcoxen-U-Test were applied.

RESULTS

The variables discovered to be of use in prediction were age (p = 0.02), anamnesis duration (p = 0.04), CMI (p < 0.000) and HHS (p = 0.001). A decision tree using solely HHS and CMI was established allowing outcome prediction of sufficient power. Interestingly, in patients who had favourable preconditions, older age impeded not a favourable prognosis.

CONCLUSION

With our proposed decision tree, a minimum of data allow a clinician to sufficiently judge whether shunting will be of benefit to a patient, which may help to decide whether invasive ancillary tests are justified.

Clinical and economic consequences of antibiotic-impregnated cerebrospinal fluid shunt catheters

OBJECT

The authors evaluated the safety and efficacy of antibiotic-impregnated shunt catheters (AISCs) and determined the cost-benefit ratio related to the fact that AISCs increase the implant costs of a shunt procedure by approximately $400 per patient.

METHODS

The control group comprised 98 adults with chronic hydrocephalus and 22 children, who were treated without AISCs (non-AISCs). In the treatment group, AISCs (Bactiseal, Codman, Johnson & Johnson) were implanted in 171 adults and 26 children. The minimum follow-up period was 6 months.

RESULTS

Important risk factors for shunt infections (such as age, comorbidity, cause of hydrocephalus, operating time, and duration of external cerebrospinal fluid drainage prior to shunt placement) did not differ between the study and control groups. In the pediatric AISC group, the frequency of premature, shunt-treated infants and the incidence of external ventricular drainage prior to shunt insertion were actually higher than those in the non-AISC group. When using AISCs, the shunt infection rate dropped from 4 to 0.6% and from 13.6 to 3.8% in the adult and the pediatric cohort, respectively. Overall the infection rate decreased from 5.8 to 1%, which was statistically significant (p = 0.0145). The average costs of a single shunt infection were $17,300 and $13,000 in children and adults, respectively. The cost-benefit calculation assumed to have saved shunt infection-related costs of approximately $50,000 in 197 AISC-treated patients due to the reduction in shunt infection rate in this group compared with costs in the control group. Despite the incremental implant costs associated with the use of AISCs, the overall reduction in infection-related costs made the use of AISCs cost beneficial in the authors' department.

CONCLUSIONS

From clinical and economic perspectives, AISCs are seemingly a valuable addition in hydrocephalus therapy.

The influence of co-morbidity on the postoperative outcomes of patients with idiopathic normal pressure hydrocephalus (iNPH)

BACKGROUND

A critical question in the diagnosis and treatment of idiopathic normal pressure hydrocephalus (iNPH) is that of which preoperative factors can most reliably predict outcomes following shunt insertion. The number and type of co-morbidities are increasingly being viewed as important predictive indicators.

METHODS

Between 1997 and 2004, 95 patients were implanted with a gravitational ventriculo-peritoneal shunt as treatment for iNPH. All coincident disease processes were recorded. Eighty-two of these patients underwent follow-up 2 years postoperatively. The results of this prospective follow-up examination (Kiefer Score, NPH Recovery Rate) were compared with the preoperative CoMorbidity Index (CMI).

FINDINGS

Of the patients with a CMI score of 0-1 (n = 18), 67% experienced an excellent outcome, 28% a good outcome and 5% and 0% a fair and poor outcome respectively. A CMI score of 2-3 was associated with markedly poorer outcomes (n = 33); 42% excellent, 30% good, 18% fair and 10% poor. A score of 4-5 was related to 14% excellent, 27% good, 23% fair and 36% poor outcomes (n = 22). Remarkably few patients scoring between 6 and 8 on the CMI scale experienced a favourable outcome. The outcomes for this latter group were 0% excellent, 10% good, 45% fair and 45% poor (n = 9) significant predictor of the quality of clinical outcome for patients with iNPH undergoing shunt therapy.