Is endoscopic third ventriculostomy a viable treatment option for normal pressure hydrocephalus? A systematic review

Background

Endoscopic third ventriculostomy (ETV) is considered an alternative treatment for hydrocephalus and has become a standard of care for obstructive hydrocephalus. Recent studies have also explored its role in normal pressure hydrocephalus (NPH). We conducted a systematic review aiming to assess the outcomes of this minimally invasive endoscopic technique as a viable treatment option for NPH.

Methods

A systematic literature search was performed using PubMed and Scopus databases, using iterations of search terms "Endoscopic third ventriculostomy," "Idiopathic normal pressure hydrocephalus," and "Normal pressure hydrocephalus." To be eligible for inclusion in the review, articles had to report the usage of ETV as a primary treatment modality for NPH, report its outcomes, and be published in the English language.

Results

Out of the 13 studies selected for qualitative synthesis, nine supported the use of ETV for NPH as an effective treatment option with improvement in the preoperative symptoms. Two studies favored shunt over ETV, stating that quality of life is better with VP shunt insertion. One study reported that ETV has higher perioperative mortality rates that outweigh its benefits. One study reported it to be an ineffective surgical option.

Conclusion

The current review of evidence does not support the use of ETV for the treatment of NPH, except perhaps in a small subset of patients. These patients have a shorter duration of symptoms and a better preoperative neurological status. The lumbar infusion test and ventricular infusion test are modalities useful for selecting these candidates.

Endoscopic third ventriculostomy compared to ventriculoperitoneal shunt as treatment for idiopathic normal pressure hydrocephalus: a systematic review and meta-analysis

BACKGROUND

The accepted treatment for idiopathic normal pressure hydrocephalus (iNPH) is the insertion of a ventriculoperitoneal shunt (VPS). Recently, some studies examined endoscopic third ventriculostomy (ETV) for the treatment of iNPH with controversial results. The aim of this systematic review and meta-analysis was to compare ETV to VPS regarding complications and outcome for the treatment of iNPH.

METHODS

We searched Medline, Embase and Scopus. Due to the scarcity of data, we did not include only randomized controlled trials, but also retro- and prospective studies. The primary outcome was failure of cerebrospinal fluid diversion method. Secondary endpoints were clinical postoperative improvement rate, morbidity and mortality.

RESULTS

Out of 311 screened studies, three were included in the quantitative analysis including one RCT and two retrospective cohort studies. No statistically significant difference concerning failure rate of CSF diversion method (ETV 27.5% vs. VPS 33.2%, RR 1.19, 95% CI [0.69-2.04], p = 0.52) or postoperative improvement was found (68% for ETV vs. 72.8% for VPS, RR 0.81, 95% CI [0.57-1.16], p = 0.26). ETV showed a significantly lower complication rate compared to VPS (7.5% vs. 51.1%, RR 0.25, 95% CI [0.08-0.76], p = 0.02).

CONCLUSION

ETV and VPS did not differ significantly regarding their failure rate for iNPH, while ETV showed a significantly lower complication rate than VPS. However, the data available is scarce with only one RCT investigating this important matter. Further well-designed trials are necessary to investigate the clinical outcome of ETV in iNPH.

TRIAL REGISTRATION NUMBER

PROSPERO (ID: CRD42020199173).

Addressing the Devil Within: Normal Pressure Hydrocephalus—A Narrative Review

Normal pressure hydrocephalus (NPH) is the most frequently occurring form of hydrocephalus among adults. It is characterized clinically by the classical triad, called Hakim's triad, comprising gait issues, cognitive impairment, and urinary problems. NPH may be primary or idiopathic (iNPH) or secondary. Characteristic neuroimaging features occur, which are vital to diagnosis. Diagnostic criteria in the form of Japanese guideline and Congress of Neurological Surgeons 2005 guidelines have been devised, and broadly, are based on a constellation of clinical and neuroimaging features, in association with cerebrospinal fluid (CSF) testing. CSF tap test, extended lumbar drainage, and CSF infusion tests are invasive diagnostic tests. CSF tap test and extended lumbar drainage are used to demonstrate clinical reversibility with CSF drainage, and patients who demonstrate this are candidates for CSF shunting. However, due to the low negative predictive value of these tests, potential response to shunting cannot be negated among patients who do not respond to CSF drainage. Various shunting procedures are used for treatment, including ventriculoperitoneal, lumboperitoneal, and ventriculoatrial shunts. Endoscopic third ventriculostomy has also been attempted with limited success. Among the clinical features, gait abnormalities are most responsive to shunting. Persistent long-term response to shunting has been reported. Patients need to be meticulously followed up after the shunting procedure, to assess clinical and neuroimaging response, and detect possible shunt-related complications, especially CSF over-drainage. Early treatment is associated with better prognosis, and it is crucial to recognize and treat this condition before the development of severe symptoms.

Evaluation of Surgical Treatment Effect on Idiopathic Normal Pressure Hydrocephalus

Background:

We aimed to observe the long-term effectiveness and safety of the ventriculoperitoneal (VP) shunt in treating idiopathic normal pressure hydrocephalus (iNPH).

Methods

A total of 65 patients with iNPH were retrospectively analyzed. All the patients were treated with VP shunt and the clinical efficacy was assessed using follow-up questionnaire, the Modified Rankin Scale (mRS), and iNPH grading scale (iNPHGS) after operation.

Results

The mean mRS and iNPHGS scores were 1.18 ± 0.83 points and 2.98 ± 1.96 points, respectively, which were statistically significantly different from those before operation [(2.89 ± 0.92) points and (6.49 ± 2.30) points, respectively]. Besides, the patients were divided into the non-improvement group (n = 8, 12.3%), the improvement group (n = 16, 24.6%), and the marked improvement group (n = 41, 63.1%) based on the preoperative and postoperative mRS scores and the total effective rate of the VP shunt was 87.7%. Next, seven patients with negative cerebrospinal fluid tap test (tap test) received the active VP shunt and the score on walking disorder was 2.71 ± 0.76 points before operation and 1.86 ± 0.90 points after operation, showing a statistically significant difference. Moreover, 12 (18.4%) patients had complications after operation, among whom 5 (7.7%) patients manifested ameliorated symptoms after replacing shunt tube and receiving anti-infection treatment, but 3 (4.6%) patients showed no alleviation following pressure adjustment due to advanced age and multiple complications. Six (9.2%) cases of death were recorded during follow-up and only 1 (1.5%) case of sudden death occurred within 2 weeks after operation. In addition, it was found through more than 5 years of follow-up after operation that 12 out of the 23 (52.2%) patients had a good effect at 5 years after operation, 1 (4.3%) patient had been confined to bed due to advanced age and pulmonary infection, and 1 (4.3%) patient died of pulmonary infection and heart failure.

Conclusion

The VP shunt is effective in treating iNPH and it results in a preferable long-term prognosis.

A comparison of Adult and Pediatric Hydrocephalus

Hydrocephalus is a common clinical problem encountered in neurosurgical practice. With greater subspecialisation, pediatric neurosurgery has emerged as a special discipline in several countries. However, in the developing world, which inhabits a large pediatric population, a limited number of neurosurgeons manage all types of hydrocephalus across all ages. There are some essential differences in pediatric and adult hydrocephalus. The spectrum of hydrocephalus of dysgenetic origin in a neonate and that of normal pressure hydrocephalus of the old age has a completely different strategy of management. Endoscopic third ventriculostomy outcomes are known to be closely associated with age at presentation and surgery. Efficacy of alternative pathways of CSF absorption also differs according to age. Managing this disease in various age groups is challenging because of these differences in etiopathology, tempo of the disease, modalities of investigations and various treatment protocols as well as prognosis.

Advances in CSF shunt devices and their assessment for the treatment of hydrocephalus

INTRODUCTION

Hydrocephalus is a neurological disorder caused by excessive accumulation of the cerebrospinal fluid (CSF) in the ventricles of the brain. It can be treated by diverting the extra fluid to different parts of the body using a device called a shunt. This paper reviews different shunt devices that are used for this purpose.

AREAS COVERED

Shunts have high failure rates either due to infection or mechanical failure, therefore there is still ongoing work to address these two main handicaps. They require additional devices for performance assessment. Here, the paper also reviews different approaches for assessing shunt limitations. Moreover, future prospects are also discussed.

EXPERT OPINION

This study shows that shunt devices still remain an important treatment option for hydrocephalus. However, further efforts are required to design more advanced shunts, to eliminate high failure rates in clinical use. Sophisticated sensor systems that can accurately detect and regulate changes in CSF drainage to optimize drainage for individual needs. Moreover, shunt infection problem is still present despite recent improvements such as antibiotic impregnated catheters.

Guidelines for Management of Idiopathic Normal Pressure Hydrocephalus (Third Edition): Endorsed by the Japanese Society of Normal Pressure Hydrocephalus

Among the various disorders that manifest with gait disturbance, cognitive impairment, and urinary incontinence in the elderly population, idiopathic normal pressure hydrocephalus (iNPH) is becoming of great importance. The first edition of these guidelines for management of iNPH was published in 2004, and the second edition in 2012, to provide a series of timely, evidence-based recommendations related to iNPH. Since the last edition, clinical awareness of iNPH has risen dramatically, and clinical and basic research efforts on iNPH have increased significantly. This third edition of the guidelines was made to share these ideas with the international community and to promote international research on iNPH. The revision of the guidelines was undertaken by a multidisciplinary expert working group of the Japanese Society of Normal Pressure Hydrocephalus in conjunction with the Japanese Ministry of Health, Labour and Welfare research project. This revision proposes a new classification for NPH. The category of iNPH is clearly distinguished from NPH with congenital/developmental and acquired etiologies. Additionally, the essential role of disproportionately enlarged subarachnoid-space hydrocephalus (DESH) in the imaging diagnosis and decision for further management of iNPH is discussed in this edition. We created an algorithm for diagnosis and decision for shunt management. Diagnosis by biomarkers that distinguish prognosis has been also initiated. Therefore, diagnosis and treatment of iNPH have entered a new phase. We hope that this third edition of the guidelines will help patients, their families, and healthcare professionals involved in treating iNPH.

Thirty-Day Hospital Readmission and Surgical Complication Rates for Shunting in Normal Pressure Hydrocephalus: A Large National Database Analysis

BACKGROUND

Research on age-related complications secondary to shunts in normal pressure hydrocephalus (NPH) is primarily limited to single-center studies and small cohorts.

OBJECTIVE

To determine the rates of hospital readmission and surgical complications, and factors that predict them, following shunt surgery for NPH in a large healthcare network.

METHODS

Surgical procedures, complications, and readmissions for adults undergoing ventricular shunting for NPH were determined using de-identified claims from a privately insured United States healthcare network in years 2007-2014. Univariate and multivariate statistics were used to determine factors that predict poor surgical outcomes. The primary outcome variable was surgical complications or readmissions (composite variable for any major perioperative complication or 30-d readmission).

RESULTS

The 30-d readmission rate for 974 patients with NPH who underwent ventricular shunting was 7.29%; the most common reasons for readmission were shunt-related complications, infection, hemorrhage, altered mental status, and cardiopulmonary and musculoskeletal problems. The perioperative complication rate was 21.15%, including intraparenchymal hemorrhage (5.85%) and extra-axial (subdural or epidural) hematoma (5.54%). The overall rate of having a surgical complication or 30-d readmission was 25.15%. Age did not predict surgical complication or 30-d readmission. Preoperative comorbidities independently associated with poor outcome were myocardial infarction within 1 yr (OR = 3.984, 95% CI = 1.105-14.368); existing cerebrovascular disease (odds ratio [OR] = 2.206, 95% CI = 1.544-3.152); and moderate/severe renal disease (OR = 2.000, 95% CI = 1.155-3.464).

CONCLUSION

The rate of complications or readmission within 30 d of ventricular shunting for NPH is 25.15%. Preoperative comorbidities of myocardial infarction within 1 yr, cerebrovascular disease, and moderate/severe renal disease are independent risk factors for poor outcome.

Gaps, Controversies, and Proposed Roadmap for Research in Normal Pressure Hydrocephalus

Idiopathic normal pressure hydrocephalus is considered common but remains underinvestigated. There are no uniformly accepted diagnostic criteria and therapeutic guidelines. We summarize the accumulated evidence regarding the definition, pathophysiology, diagnosis, and treatment of idiopathic normal pressure hydrocephalus, highlighting the many gaps and controversies, including diagnostic challenges, the frequent association with neurodegeneration and vascular disease, and the many unknowns regarding patient selection and outcome predictors. A roadmap to fill these gaps and solve the controversies around this condition is also proposed. More evidence is required with respect to diagnostic criteria, the value of ancillary testing, prospective population-based studies and novel trial designs. Furthermore, a need exists to develop new advanced options in shunt technology. © 2020 International Parkinson and Movement Disorder Society.

Current Updates on Idiopathic Normal Pressure Hydrocephalus

Idiopathic normal pressure hydrocephalus (iNPH) is one of the neurodegenerative diseases which can be treated surgically with favorable outcome. The gait disturbance, cognitive, and urinary symptoms are known as the clinical triad of iNPH. In this review, we have addressed the comorbidities, differential diagnoses, clinical presentations, and pathology of iNPH. We have also summarized the imaging studies and clinical procedures used for the diagnosis of iNPH. The treatment modality, outcomes, and prognosis were also discussed.

Establishing a Preoperative Evaluation System for Lumboperitoneal Shunt: Approach to Attenuate the Risk of Shunt Failure

OBJECTIVE

Lumboperitoneal shunt (LPS) has been demonstrated an effective method for the treatment of communicating hydrocephalus in the presence of frequent shunt failure. The objective of the present study was to determine whether establishing a preoperative evaluation system could benefit patients, thus attenuating the risk of LPS failure.

METHODS

In this 3-year study, treated by LPS, patients undergoing preoperative evaluation were included into the study group and other individuals without preoperative evaluation were included into the control group. Perioperative conditions, including Keifer's hydrocephalus score, symptomatic control rate, Evans index, complications, long-term shunt revision rate, and quality of life, were synchronously investigated.

RESULTS

A total of 93 eligible patients were included in the study (study group, 51; control group, 42). The baseline characteristics of the 2 groups were basically similar. The results showed that patients in the study group had better short-term improvement in symptoms and imageology, including higher symptomatic control rate (median, 62.5% vs. 50%; P = 0.001), more reduction in Evans index (0.08 ± 0.05 vs. 0.05 ± 0.04; P = 0.002), and lower incidence of postoperative complications (median, 35.3% vs. 57.1%; P = 0.04). Similarly, the incidence of shunt revision in the study group was dramatically lower than in the control group (median, 15.7% vs. 40.9%; P = 0.006) in line with the revision-free curve (P = 0.002), which suggested that most of patients received revision, if needed, within 3 months. In addition, patients in the study group had better quality of life.

CONCLUSIONS

In conclusion, patients who underwent evaluation before LPS had better short-term and long-term outcomes, suggesting that it would be a promising strategy to correctly select patients for LPS with prolonged favorable shunt outcomes.

Asymmetric hearing loss and chronic dizziness in a patient with idiopathic normal pressure hydrocephalus

We report a case of a 54-year old female patient, complaining for chronic dizziness, hearing loss, tension headaches without aura, postural instability and gait dysfunction. The patient referred having these symptoms from 1992, but the last few months she experienced a noticeable aggravation of the symptoms. A magnetic resonance imaging test revealed a triventricular hydrocephalus, not associated with signs of intracranial hypertension decompensation. The ENT-Audiology evaluation revealed a bilateral sensorineural hearing loss with a conductive component, video-nystagmography resulted in an areflexia of the right ear and a reduced vestibular activity for the left ear. Auditory brainstem response test was also carried out and showed pathologic findings for the latencies of the waves I-III, III-V and I-V bilaterally but more significant in the right ear. On January 2016 the patient had endoscopic third ventriculostomy. On the follow up the patient referred an important subjective improvement regarding instability and gait dysfunction. In this paper we study the correlation between hydrocephalus, hearing loss and vestibular dysfunction.

Efficacy of endoscopic third ventriculostomy in old aged patients with normal pressure hydrocephalus

Normal pressure hydrocephalus (NPH) is a chronic disorder caused by interrupted CSF absorption or flow. Generally, shunt placement is first option for NPH treatment. Due to complications of ventriculo-peritoneal (VP) shunt placement, endoscopic third ventriculostomy (ETV) can be considered as an alternative treatment option. Here we report the efficacy of ETV especially in old aged patients with normal pressure hydrocephalus. Total 21 old aged patients with communicating hydrocephalus with opening pressure, measured via lumbar puncture, less than 20cm H₂O underwent ETV. 15 patients had primary/idiopathic NPH and 6 patients had secondary NPH. All patients were studied with a MRI to observe the flow void at aqueduct and the fourth ventricle outflow. And all of them underwent ETV. In a group with peak velocity was higher than 5cm/s, nine patients (75%) were evaluated was 'favorable' and three of them (25%) was scored 'poor'. In another group with peak velocity less than 5cm/s, three of them were scored 'poor' and two of them were scored 'stable'. None of them was evaluated as 'favorable'. We also evaluated the outcomes according to etiology: 12 patients (80% of the patients with primary NPH) were evaluated with 'favorable' after ETV treatment. Two patients (13.3%) were as 'stable'. And one patient was as 'poor' evaluated. Five patients (83.3%) among patients with secondary NPH were as 'poor' evaluated and one of them was stable and no patient was as 'favorable' evaluated. 4 patients, which was as 'poor' evaluated in the group with the secondary NPH, underwent additional VP shunt implantation. Overall, the outcomes of the group with the idiopathic NPH after ETV treatment were more favorable than of the group with the secondary NPH. Our study suggest that ETV can be effective for selected elderly patients with primary/idiopathic NPH, when they satisfy criteria including positive aqueduct flow void on T2 Sagittal MRI and the aqueductal peak velocity, which is greater than 5cm/s on cine MRI.

The Clinical Effect of Postoperative Hyperbaric Oxygen Therapy on Idiopathic Normal Pressure Hydrocephalus: A Retrospective and Comparative Analysis of 61 Patients with Ventriculoperitoneal Shunt

OBJECTIVE

The aim of the study was to examine the clinical effect of postoperative hyperbaric oxygen (HBO) therapy on symptoms and signs in the ventriculoperitoneal (VP) shunt insertion treatment of idiopathic normal pressure hydrocephalus (iNPH).

METHODS

We conducted a retrospective analysis of 61 patients treated at our institution for iNPH since 2007. Patients were stratified into 2 groups according to undergoing pure VP shunt with gravitational valves (group 1) or combined with postoperative HBO therapy (group 2). Clinical improvements as well as complications were compared between the 2 groups.

RESULTS

There was no significant difference between the 2 groups regarding age, sexual proportion, body mass index, education years, and the average Normal Pressure Hydrocephalus Scale score before the surgery, as well as the complication rate after the surgery (P > 0.05). On average, the total Normal Pressure Hydrocephalus Scale scores were both increased in the 2 groups at 1, 3, and 6 months after shunting, with no significant differences (P > 0.05). However, group 2 tended to increase more compared with group 1, especially 6 months later after shunting. The increase of cognitive functions was more significant in group 2 (P < 0.05).

CONCLUSIONS

HBO therapy combined with VP shunt is expected to improve the effect of iNPH treatment, especially for cognitive performance.

A Review of Clinical Outcomes for Gait and Other Variables in the Surgical Treatment of Idiopathic Normal Pressure Hydrocephalus

BACKGROUND

Idiopathic normal pressure hydrocephalus (INPH) is a treatable cause of gait disturbance, cognitive impairment, and urinary incontinence. This clinical triad of symptoms occurs in association with ventriculomegaly and normal cerebrospinal fluid (CSF) pressure. Although the treatment outcomes after CSF shunting for INPH have improved significantly since its first description in 1965, shortcomings in our understanding still remain. Not all INPH patients exhibit clinical improvement after shunting, and it is challenging to identify patients who are more likely to benefit from shunting.

METHODS

The Cochrane Library, Medline, Embase, and PubMed databases were searched for English-language publications between 1965 and October 2015. Reference lists of publications were also manually searched for additional publications.

RESULTS

The findings of this review indicate that, despite efforts to improve patient selection, the degree of clinical improvement after shunting continues to demonstrate significant variability both within and between studies. These discrepancies in treatment outcomes are the result of controversies in 3 distinct but interrelated domains: the underlying pathophysiology of INPH, the diagnosis of INPH, and the identification of likely shunt-responders.

CONCLUSIONS

This review focuses on these 3 areas and their relation to surgical treatment outcomes. Despite the limitations of published outcome studies and limitations in our understanding of INPH pathophysiology, shunting is a safe and effective means of achieving meaningful clinical improvement in most patients with INPH.

Comparison of Intracranial Neuroendoscopic Procedures in Children versus Adults

BACKGROUND

The emphasis regarding intracranial neuroendoscopy has been traditionally advocated and focused on the role in pediatric patients, although a significant usage has developed in adult patients. In this study, we examine and contrast the role of predominantly intracranial neuroendoscopy in both a pediatric and adult population with a minimum postprocedure follow-up of 5 years.

METHODS

A retrospective review was conducted for patients in the two hospitals that manage neurosurgical care for Southern Alberta, Canada, undergoing neuroendoscopic surgery between 1994 and 2008. The pediatric group was defined as age ≤17 years and the adult group as age ≥18 years.

RESULTS

A total of 273 patients who underwent a total of 330 procedures with a mean postprocedure follow-up of 12.9 years were identified. There were 161 adult and 112 pediatric patients, and both groups underwent surgery by the same surgeons. The most common procedure was endoscopic third ventriculostomy, accounting for 55% of procedures. One postoperative death occurred in an adult patient. Endoscopic third ventriculostomy success 1-year postprocedure was 81%, with only three late-term failures. Postoperative infection was the most common serious complication (two pediatric/four adult patients). Adult and pediatric patients had similar major complication rates (4.2% vs 5.7%, p=0.547).

CONCLUSIONS

Neuroendoscopy overall had a similar role in both pediatric and adult neurosurgical populations, with the most commonly associated complication being infection. Neuroendoscopy is an important therapeutic modality in the management of appropriate adult patients.

Endoscopic Third Ventriculostomy in 250 Adults With Hydrocephalus

BACKGROUND:

Endoscopic third ventriculostomy (ETV) has been used predominantly in the pediatric population in the past. Application in the adult population has been less extensive, even in large neurosurgical centers. To our knowledge, this report is one of the largest adult ETV series reported and has the consistency of being performed at 1 center.

OBJECTIVE:

To determine the efficacy, safety, and outcome of ETV in a large adult hydrocephalus patient series at a single neurosurgical center. In addition, to analyze patient selection criteria and clinical subgroups (including those with ventriculoperitoneal shunt [VPS] malfunction or obstruction and neurointensive care unit patients with extended ventricular drainage before ETV) to optimize surgical results in the future.

METHODS:

We conducted a retrospective review of adult ETV procedures performed at our center between 2000 and 2014.

RESULTS:

The overall rate of success (no further cerebrospinal fluid diversion procedure performed plus clinical improvement) of 243 completed ETVs was 72.8%. Following is the number of procedures with the success rate in parentheses: aqueduct stenosis, 56 (91%); communicating hydrocephalus including normal pressure hydrocephalus, nonnormal pressure hydrocephalus, and remote head trauma, 57 (43.8%); communicating hydrocephalus in postoperative posterior fossa tumor without residual tumor, 14 (85.7%); communicating hydrocephalus in subarachnoid hemorrhage without intraventricular hemorrhage, 23 (69.6%); obstruction from tumor/cyst, 42 (85.7%); VPS obstruction (diagnosis unknown), 23 (65.2%); intraventricular hemorrhage, 20 (90%); and miscellaneous (obstructive), 8 (50%). There were 9 complications in 250 intended procedures (3.6%); 5 (2%) were serious.

CONCLUSION:

Use of ETV in adult hydrocephalus has broad application with a low complication rate and reasonably good efficacy in selected patients.

Evidences in the treatment of idiopathic normal pressure hydrocephalus

INTRODUCTION

idiopathic normal pressure hydrocephalus (INPH) is characterized by gait apraxia, cognitive dysfunction and urinary incontinence. There are two main treatment options: ventriculoperitoneal shunt (VPS) and endoscopic third ventriculostomy (ETV). However, there are doubts about which modality is superior and what type of valve should be applied. We are summarizing the current evidence in INPH treatment.

METHODS

an electronic search of the literature was conducted on the Medline, Embase, Scielo and Lilacs databases from 1966 to the present to obtain data published about INPH treatment.

RESULTS

the treatment is based on three pillars: conservative, ETV and VPS. The conservative option has fallen into disuse after various studies showing good results after surgical intervention. ETV is an acceptable mode of treatment, but the superiority of VPS has made the latter the gold standard.

CONCLUSION

well-designed studies with a high level of appropriate evidence are still scarce, but the current gold standard for treatment of INPH is conducted using VPS.

Endoscopic third ventriculostomy (ETV) for idiopathic normal pressure hydrocephalus (iNPH)

BACKGROUND

Idiopathic normal pressure hydrocephalus (iNPH) is a type of communicating hydrocephalus also known as non-obstructive hydrocephalus. This type of hydrocephalus is caused by impaired cerebrospinal fluid reabsorption without any obstruction in the ventricular system and is associated with normal cerebrospinal fluid pressure. It is characterised clinically by gait disturbance, cognitive dysfunction, and urinary incontinence (known as the Hakim-Adams triad). The exact cause of iNPH is unknown. It may be managed conservatively or treated surgically by inserting a ventriculoperitoneal (VP) or ventriculoatrial (VA) shunt. However, a substantial number of patients do not respond well to surgical treatment, complication rates are high and there is often a need for further surgery. Endoscopic third ventriculostomy (ETV) is an alternative surgical intervention. It has been suggested that ETV may lead to better outcomes, including fewer complications.

OBJECTIVES

To determine the effectiveness of ETV for treatment of patients with iNPH compared to conservative therapy, or shunting of CSF using VP or VA shunts.To assess the perioperative and postoperative complication rates in patients with iNPH after ETV compared to conservative therapy, VP or VA shunting.

SEARCH METHODS

We searched for eligible studies using ALOIS: a comprehensive register of dementia studies, The Cochrane Central Register of Controlled Trials (CENTRAL) and several bibliographic databases such as MEDLINE (Ovid SP), EMBASE (Ovid SP), PsycINFO (Ovid SP), CINAHL (EBSCOhost) and LILACS (BIREME).We also searched the Database of Abstracts of Reviews of Effects (DARE) to identify potentially relevant reviews. The search strategy was adapted for other databases, using the most appropriate controlled vocabulary for each. We did not apply any language or time restrictions. The searches were performed in August 2014.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of ETV treatment of iNPH. Patients had to have at least two symptoms of the Hakim-Adams triad. Exclusion criteria were obstructive causes of hydrocephalus, other significant intracranial pathology and other confirmed causes of dementia. The eligible comparators were conservative treatment or shunting using VP and VA shunts.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened search results, selected eligible studies, assessed risk of bias and extracted data. We contacted trial authors for additional data.

MAIN RESULTS

Only one study met the inclusion criteria: an RCT comparing effectiveness of ETV and non-programmable VP shunts in 42 patients with iNPH. The study was conducted in Brazil between 2009 and 2012. The overall study risk of bias was high. The primary outcome in the study was the proportion of patients with improved symptoms one year after surgery, determined as a change of at least two points on the Japanese NPH scale. Due to imprecision in the results, it was not possible to determine whether there was any difference between groups in the proportion of patients who improved 3 or 12 months after surgery (3 months: odds ration (OR) 1.12, 95% confidence interval (CI) 0.26 to 4.76, n = 42; 12 months: OR 2.5, 95% CI 0.62 to 10.11, n = 38). We were unable to estimate the effect of treatment on other efficacy outcomes (cognition, balance, function, gait and mobility) because they were inadequately reported. Of the 26 patients in the VP shunting group, 5 developed subdural hematoma postoperatively, while there were no complications among the 16 patients in the ETV group (OR 0.12, 95% CI 0.01 to 2.3, n = 42), but the estimate was too imprecise to determine whether this was likely to reflect a true difference in complication rates. This was also the case for rates of further surgical intervention (OR 1.4, 95% CI 0.31 to 6.24, n = 42). There were no deaths during the trial. We judged the quality of evidence for all outcomes to be very low because of a high risk of selection, attrition and reporting bias and serious imprecision in the results.

AUTHORS' CONCLUSIONS

The only randomised trial of ETV for iNPH compares it to an intervention which is not a standard practice (VP shunting using a non-programmable valve). The evidence from this study is inconclusive and of very low quality. Clinicians should be aware of the limitations of the evidence. There is a need for more robust research on this topic to be able to determine the effectiveness of ETV in patients with iNPH.