Ventriculoatrial Shunt Research Articles

Communicating chronic hydrocephalus: A review

Formerly called normal pressure hydrocephalus, communicating chronic hydrocephalus (CCH) is a condition affecting 0.1 to 0.5% of patients over 60years of age. The pathophysiology of this disease is poorly understood, but a defect in cerebrospinal fluid (CSF) resorption appears to be commonly defined as the cause of the neurological disorders. The last important discovery is the description of the glymphatic system and its implication in CCH and CSF resorption. Comorbidities (Alzheimer's disease, microangiopathy, parkinsonism) are very frequent, and involve a diagnostic challenge. The clinical presentation is based on the Hakim and Adams triad, comprising gait disorders, mainly impairing walking, cognitive disorders, affecting executive functions, episodic memory, visuospatial cognition, and sphincter disorders as urinary incontinence (detrusor hyperactivity). The diagnosis is suspected through a set of arguments, combining the clinical presentation, the radiological data of the magnetic resonance imaging (MRI) showing a ventriculomegaly associated with signs of transependymomous resorption of the CSF and disappearance of the cortical sulci, and the clinical response to the depletion of CSF. In the presence of all these elements, or a strong clinical suspicion, the standard treatment will be of a permanent CSF shunt, using a ventriculoatrial or ventriculoperitoneal shunt. The effectiveness of this treatment defines the diagnosis. The clinical improvement is better when treatment occurs early after the onset of the disorders, reaching 75 to 90% of motor improvement.

Reconversion to ventriculoperitoneal shunt following ventriculoatrial shunt malfunction in children.

To analyze the long-term efficacy of the ventriculoatrial shunt (VAS) in pediatric patients with hydrocephalus, focusing on the atrial catheter and suitable revision procedures of the distal catheter following VAS malformation performed at our institution. The authors retrospectively analyzed data of 28 pediatric patients under the age of 10years who were treated with VAS for hydrocephalus and who had a follow-up period of at least 5years. A total of 42 atrial tube revision procedures were performed in 28 patients during the study period. The median atrial tube survival time due to atrial tube obstruction was 2.32years (n = 31, range: 0.4-8.08years). Atrial tube survival time was shorter in younger children (p < 0.0001) and in children who were shorter in height (p = 0.0001). As a revision procedure following atrial tube malfunction, 22 (78.6%) out of the 28 patients who had an inserted VAS had the VAS reconversion into a VPS at the last follow-up. VAS can be a useful alternative to VPS, but it requires frequent atrial tube revisions, especially in younger children. Reconversion to VPS after VAS malfunction is a reasonable option and is associated with longer shunt survival time despite its previously observed difficulties.

Utility of ventriculogallbladder shunts in complex cases of hydrocephalus related to extreme prematurity.

The management of hydrocephalus resulting from intraventricular hemorrhage related to extreme prematurity remains demanding. Given the complexities of controlling hydrocephalus in this population, less commonly used procedures may be required. The authors examined the utility of ventriculogallbladder (VGB) shunts in a series of such children. The authors retrospectively reviewed the medical records of all children who underwent surgery for hydrocephalus in the period from 2011 through 2019 at Children's Healthcare of Atlanta. Six patients who underwent VGB shunt placement were identified among a larger cohort of 609 patients who had either a new shunt or a newly changed distal terminus site. The authors present an analysis of this series, including a case of laparoscopy-assisted distal VGB shunt revision. The mean age at initial shunt placement was 5.1 months (range 3.0-9.4 months), with patients undergoing a mean of 11.8 shunt procedures (range 5-17) prior to the initial VGB shunt placement at a mean age of 5.3 years (range 7.9 months-12.8 years). All 6 patients with VGB shunt placement had hydrocephalus related to extreme prematurity (gestational age < 28 weeks). At the time of VGB shunt placement, all had complex medical and surgical histories, including poor venous access due to congenital or iatrogenic thrombosis or thrombophlebitis and a peritoneum hostile to distal shunt placement related to severe necrotizing enterocolitis. VGB complications included 1 case of shunt infection, identified at postoperative day 6, and 2 cases of distal shunt failure due to retraction of the distal end of the VGB shunt. In all, there were 3 conversions back to ventriculoperitoneal or ventriculoatrial shunts due to the 2 previously mentioned complications, plus 1 patient who outgrew their initial VGB shunt. Three of 6 patients remain with a VGB shunt, including 1 who underwent laparoscopy-assisted distal shunt revision 110.5 months after initial VGB shunt insertion. Placement of VGB shunts should be considered in the armamentarium of procedures that may be used in the particularly difficult cohort of children with hydrocephalus related to extreme prematurity. VGB shunts show utility as both a definitive treatment and as a "bridge" procedure until the patient is larger and comorbid abdominal and/or vascular issues have resolved sufficiently to allow conversion back to ventriculoperitoneal or ventriculoatrial shunts, if needed.

The Role Of Ventriculoatrial Shunts For The Shunt Placement In Modern Medicine : A Case Report

Introduction: Although Ventriculoatrial (VA) shunt is one of the oldest solution for hydrocephalus, after the recognition of serious complication and operative difficulties, VA shunt procedure has fallen into disrepute. Since 1970s, most of neurosurgeons has changed their practice from VA shunt to ventriculoperitoneal (VP) shunt. It provides a prolong relief of intracranial pressure and easy to be performed. However, shunt revision may still be expected due to shunt infection, obstruction, migration and so on. When the peritoneum is precluded and no more available owing to the intra-abdominal adhesions, local sepsis and scarring from the previous surgery, VA shunt can be one of the choices to do the shunt revision. Whenever laparotomy for VP shunt has high possibility of serious complications and operative difficulties due to preexisting peritoneal compolication, VA shunt can be a safe and effective alternative in the neurosurgeon’s armamentarium for the cerebrospinal fluids (CSF) drainage. Case Report: In this case report, we described a case of premature 6-month-old baby boy with hydrocephalus, whose abdominal cavity had the previous history of peritonitis and stoma placement. Result: Because his abdominal condition excluded placement of a distal catheter for VP shunt, VA shunt was planned as alternative procedure for VP shunt. Conclusion: Role of VA shunt in the era of modern neurosurgery is also discussed based on the literature review.

The survival of reimplanted shunts following externalization: a single-institution cohort study.

The failure-free survival of ventriculoperitoneal shunts (VPSs) following externalization for distal catheter infection or malfunction has not been adequately explored. Conversion to a ventriculoatrial shunt (VAS) may allow earlier reinternalization in lieu of waiting for the peritoneum to be suitable for reimplantation. This option is tempered by historical concerns regarding high rates of VAS failure, and the risks of rare complications are rampant. In this retrospective cohort study, all patients undergoing externalization of a VPS at a single institution between 2005 and 2020 were grouped according to the new distal catheter terminus location at the time of reinternalization (VPS vs VAS). The primary outcomes were failure-free shunt survival and duration of shunt externalization. Secondary outcomes included early (< 6 months) shunt failure. Among 36 patients, 43 shunt externalization procedures were performed. Shunts were reinternalized as VPSs in 25 cases and VASs in 18 cases. The median failure-free survival was 1002 (interquartile range [IQR] 161-3449) days for VPSs and 1163 (IQR 360-2927) days for VASs. There was no significant difference in shunt survival according to the new distal catheter terminus (log-rank, p = 0.73). Conversion to a VAS was not associated with shorter duration of shunt externalization (Wilcoxon rank-sum, p = 0.64); the median duration was 7 (IQR 5-11) days for VPSs and 8 (IQR 6-15) days for VASs. No rare complications occurred in the VAS group. Shunt failure-free survival rates following externalization are similar to published survival rates for nonexternalized shunts. There was no significant difference in survival between reinternalized VPSs and VASs. Although the VAS was not associated with a shortened duration of externalization, this finding is confounded by strong institutional preference for the VPS over the VAS. Early conversion to the VAS may be a viable treatment option in light of reassuring modern VAS survival data.

Shunt Nephritis: A Rare and Forgotten Diagnosis

Shunt nephritis is a rare complication of ventriculoatrial and ventriculoperitoneal shunt infection. The clinical manifestations are nonspecific and include asthenia, arthralgias, anorexia, weight loss, hematuria, proteinuria, and progressive renal impairment. Therefore, diagnosis can be delayed up for to several years after the first clinical manifestations, which increases the risk of progressive renal impairment and neurological dysfunction. A 57-year-old woman who had undergone ventriculoperitoneal shunt placement in 1990 was admitted to the nephrology department to perform an elective kidney biopsy due to hematuria, proteinuria, and rapidly progressive renal failure. The patient presented with asthenia and weight loss with a duration of one year. No other symptoms were reported. The kidney biopsy was suggestive of infection associated glomerulonephritis, particularly a subacute infection, as a membranoproliferative pattern was seen in light microscopy, and IgM staining was predominant in immunofluorescence imaging. During the hospital stay, the patient developed neurological symptoms. Cerebrospinal fluid examination showed pleocytosis. Shunt nephritis was suspected, and antibiotic treatment was initiated. Due to the patient’s worsening neurological status, an urgent surgical shunt removal was performed. Two months later, her renal function was normal, and the urinalysis result was unremarkable, even though her neurological status did not improve. Although rare, shunt nephritis should be considered in patients that have a history of ventriculoperitoneal shunt placement and present with a proliferative or membranoproliferative glomerulonephritis and prominent IgM deposits in immunofluorescence imaging. Early diagnosis and shunt removal are critical for improving the neurological and renal prognosis.

Success Rates and Complications of Ventriculoperitoneal and Ventriculoatrial Shunting: A Systematic Review

Background and Aim: The insertion of Ventriculoperitoneal (VP) or Ventriculoatrial (VA) shunt is the first line of treatment in patients with hydrocephalus and normal-pressure hydrocephalus. The provision of a safety profile for shunting in the treatment of hydrocephalus patients is very important. This study aimed to determine the success rates and complications of VP and VA shunting in patients with hydrocephalus. Methods and Materials/Patients: This systematic review investigated the complication rates of VP and VA shunting in managing patients with hydrocephalus. All the published studies were searched in three electronic databases of Web of Science, PubMed and Google Scholar from March 20 to April 10, 2020, using the keywords of “Ventriculoperitoneal” and “Ventriculoatrial” in combination with “Hydrocephalus”. Results: In total, nine articles met the eligibility criteria for being included in this review. Some studies showed a higher rate of shunt obstruction in patients undergoing VA shunting; however, other studies demonstrated no difference in terms of shunt obstruction. The rates of primary revision shunt were various within the ranges of 5.4%-48% and 9.1%-58% for VA and VP shunting, respectively. A higher rate of revision shunt was reported among the patients undergoing VP shunting, compared to that reported for VA shunting. The different mortality rates in various studies were estimated within the range of 0%-10% and at 13.9% for VA and VP shunting, respectively. Conclusion: In general, no difference was reported between VA and VP shunting regarding the rates of complications and mortality. Due to the ease of placement and revision, VP shunting could be considered the first-line treatment of hydrocephalus. However, this approach has been preferred in newborns, and there have been insufficient data on adults in this regard.

Experience with Ventriculoatrial Shunt

Cerebrospinal fluid (CSF) diversion through shunting, either internal or external, is the standard of care for hydrocephalic patients. Although Ventriculoperitoneal (VP) shunt is always the first choice, right atrium for Ventriculoatrial (VA) shunt is considered a suitable and convenient option for drainage of excess CSF in patients with history of abdominal surgeries, peritoneal infection or shunt obstruction.1 Here we are reporting our experience with a patient who underwent VA shunt insertion because of a previous malfunctioning VP shunt. A thorough review of the literature revealed that, although reported worldwide, there is an apparent deficiency of similar reports from Arabian Gulf region. Through this case report, we aim to shed light on this internal CSF diversion method, which could be considered in centers lacking advanced care facilities for procedures like Endoscopic 3rd Ventriculostomy (ETV).

Full-mouth rehabilitation of a hydrocephalus patient

Dentists frequently encounter patients who are either medically, physically, or mentally compromised. One such medically compromised condition is “hydrocephalus.” Hydrocephalus is basically a neurological disorder caused by excessive intracranial pressure due to abnormal accumulation of cerebrospinal fluid within the ventricles or subarachnoid space of the brain and raised intracranial pressure. Ventriculoperitoneal shunt (VPS) is the most commonly used treatment, but ventriculoatrial shunt is another treatment option. To keep the intracranial pressure within normal range, the patients are kept on medications which make them more prone to dental caries. Because of poor oral hygiene, these patients require a regular dental care. This report discusses the dental management process employed for a 5-year-old patient with VPS-treated hydrocephalus.

Development of a Lumbar Extradural Arachnoid Cyst Associated with a Lumbar Catheter of Lumboperitoneal Shunt: A Case Report

A 78-year-old man, who had undergone lumboperitoneal shunt (LPS) placement for idiopathic normal-pressure hydrocephalus eight years prior, presented with intermittent claudication, lower back pain, and radicular pain on the inside of the right thigh. Magnetic resonance imaging (MRI) revealed an extradural arachnoid cyst (EDAC) above the lumbar catheter of the LPS. The EDAC compressed the spinal dural sac and cauda equina toward the anterior side at level L3/4, triggering his clinical manifestations. The LPS was removed and simultaneously converted into a ventriculoperitoneal shunt (VPS), which immediately improved the neurological deficits. Postoperative MRI showed shrinkage of the cyst and restoration of the compressed cauda equina. Spinal EDAC is a rare entity resulting from arachnoid membrane herniation due to a small defect in the dura mater. This is the first report showing that symptomatic EDAC can be accompanied by the lumbar catheter of the LPS and that a mere conversion from LPS to VPS or ventriculoatrial shunt might be sufficient to shrink LPS-related EDAC without invasive lumbar surgeries.

Cervical Venous Vascular Anatomy for Ventriculoatrial Shunt Applications: Anatomical Study and Surgical Approach Recommendation.

To develop an approach for atrial application of ventriculoatrial (VA) shunts after revealing the venous anatomy with facial and cervical anatomical dissections. Five cephalic cadavers were used in the study. Facial and cervical regions of the cephalic cadavers were examined with layer by layer anatomical dissection. Venous angiography and ultrasonography were performed to obtain additional data on the cervical venous vascular anatomy. Subsequently, we developed an approach for atrial catheter applications. No anatomical variations were detected in the dissections. The common facial vein, which was formed by the facial vein and retromandibular vein, was observed to drain into the internal jugular vein. As a result of dissections and examinations, an incision approximately 2 cm below the mandible, extending from the projection of the submandibular notch to the trace of the angulus mandible, was considered adequate to expose the common facial vein for atrial catheter insertion. The approach described in our study is appropriate for the application of an atrial catheter for VA shunts. Revealing the venous anatomy with examinations contributes to the success of the operation.

A Brief Review of Ventriculoatrial and Ventriculopleural Shunts.

Alternate approaches such as ventriculoatrial (VA) or ventriculopleural (VPL) procedures still have a place in the surgical armamentarium for patients with recurrent ventriculoperitoneal (VP) shunt failures related to defective absorption, infections, or frequent malfunctions. We reviewed the literature and our experience with these techniques, and offered suggestions for safely performing these operations. Historical perspectives were also included to facilitate an improved understanding of the technical developments. Our findings and the available medical literature suggest VA and VPL options are safe and effective alternatives for managing the complex patient with hydrocephalus. Potential issues and complications were discussed along the technical advances for a safer operation. The VA and VPL options should be considered for patients with recurrent VP shunt issues. They are safe and effective options for managing complex hydrocephalus patients.

In Reply: Transesophageal Echocardiography-Guided Ventriculoatrial Shunt Insertion.

In Reply: Transesophageal Echocardiography-Guided Ventriculoatrial Shunt Insertion.

Minimally invasive procedure for removal of infected ventriculoatrial shunts

BackgroundVentriculoatrial shunts were one of the most common treatments of hydrocephalus in pediatric and adult patients up to about 40 years ago. Thereafter, due to the widespread recognition of the severe cardiac and renal complications associated with ventriculoatrial shunts, they are almost exclusively implanted when other techniques fail. However, late infection or atrial thrombi of previously implanted shunts require removal of the atrial catheter several decades after implantation. Techniques derived from management of central venous access catheters can avoid cardiothoracic surgery in such instances.MethodsWe retrospectively investigated all the patients requiring removal of a VA shunt for complications treated in the last 5 years in our institution.ResultsWe identified two patients that were implanted 28 and 40 years earlier. Both developed endocarditis with a large atrial thrombus and were successfully treated endovascularly. The successful percutaneous removal was achieved by applying, for the first time in this setting, the endoluminal dilation technique as proposed by Hong. After ventriculoatrial shunt removal and its substitution with an external drainage, both patients where successfully weaned from the need for a shunt and their infection resolved.ConclusionPatients carrying a ventriculoatrial shunt are now rarely seen and awareness of long-term ventriculoatrial shunt complications is decreasing. However, these complications must be recognized and treated by shunt removal. Endovascular techniques are appropriate even in the presence of overt endocarditis, atrial thrombi, and tight adherence to the endocardial wall. Moreover, weaning from shunt dependence is possible even decades after shunting.

Revision and complication rates in adult shunt surgery: a single-institution study

BackgroundCSF diversion with shunt placement is frequently associated with need for later revisions as well as surgical complications. We sought to review revision and complication rates following ventriculoperitoneal, ventriculoatrial and cystoperitoneal shunt placement in adult patients, and to identify potential risk factors for revision surgery and postoperative complications.MethodIncluded patients were adults (≥ 18 years) who underwent primary shunt insertion at St. Olavs Hospital in Trondheim, Norway, from 2008 through 2017. The electronic medical records and diagnostic imaging from all hospitals in our catchment area were retrospectively reviewed. Follow-up ranged from 1 to 11 years. Complications were graded according to the Landriel Ibañez classification system.ResultsOf the 227 patients included, 47 patients (20.7%) required revision surgery during the follow-up. In total, 90 revision surgeries were performed during follow-up. The most common cause for the first revision was infection (5.7%) and for all revisions proximal occlusion (30.0%). A total of 103 patients (45.4%) experienced ≥ 1 complication(s). Mild to moderate complications (grade I and II) were detected in 35.0% of all procedures. Severe or fatal complications (grade III and IV) were observed in 8.2% of all procedures. Urinary tract infections and pneumonia were common postoperatively (13.9% and 7.3%, respectively), and the most common IIb complication was shunt misplacement (proximally or distally). Two out of fourteen deaths within 30 days were directly associated with surgery. We did not find that aetiology/indication, age or gender influenced the occurrence of revision surgery or a grade III or IV complication.ConclusionsShunt surgery continues to be a challenge both in terms of revision rates and procedure-related complications. However, the prediction of patients at risk remains difficult. A multidimensional focus is probably needed to reduce risks.

Should not we be using aspirin in patients with a ventriculoatrial shunt? Borrowing a leaf from other specialities: a case for surrogate evidence.

Ventriculoatrial (VA) shunts are life-saving in circumstances where ventriculoperitoneal shunts (VP) have failed. They are at risk for different complications, and more specific of them are cardiopulmonary complications. Currently, there are no standard recommendations concerning screening for risk factors, prophylaxis, or anticoagulation treatment in patients after VA shunt placement. Our study aims to prospectively study the possible role and efficacy of the use of aspirin to increase the survival of shunts in children with VA shunt and avoid secondary morbidity. In this article, the authors describe the interim results of an ongoing prospective study which supports the use of aspirin for VA shunt. The study design is prospective. The duration of the study is 2011 onwards and is ongoing. Hospital ethics board clearance and consent from the family were taken before inclusion in the study. All patients who had VA shunt were given a once-a-day low-antiplatelet dose of aspirin 5mg/kg, from the first postoperative day onwards. Primary endpoints of the study are as follows: (1) major distal end malfunction documented on echocardiography or (2) any cardiac complications associated with the VA shunt catheter. We have 6 patient since march 2011, who are being followed up. None of the shunts had malfunctioned until the reporting. None of the patients had any cardiac issues reported. The patients are to be followed continually. The present follow-up ranges from 2.5 to 10years. The patient follow-up is being continued. Aspirin is a drug with well-accepted safety profile, and its use and our preliminary observation and outcome of the use of aspirin in VA shunt are promising.

Ventriculoatrial and ventriculopleural shunts as second-line surgical treatment have equivalent revision, infection, and survival rates in paediatric hydrocephalus.

Ventriculoatrial (VA) and ventriculopleural (VPL) shunts are used as alternatives when CSF diversion to the peritoneal compartment with a ventriculoperitoneal (VP) shunt is not possible. The objective of this study is to compare directly the shunt survival and complications for both procedures in this setting in children. A retrospective analysis of 54 consecutive patients who underwent VA (36) or VPL (18) shunt insertion between January 2002 and December 2017 was conducted. The overall mean follow-up was 4.1 (SD 4.3) years, 2.8 (SD 4.1) for VPL and 4.7 (SD 4.4) for VA shunts, respectively (p = 0.11). Twenty-four (66.7%) patients in the VA group and 9 (50.0%) in the VPL group underwent shunt revision (p = 0.236); mean number of revisions was 2.2 (SD 3.0) and 0.94 (SD 1.4) in the VA and VPL groups (p = 0.079). Median time to failure was 8.5 (IQr 78, range 0-176) months for VA and 5.50 (IQr 36, range 0-60) for VPL shunts (log rank (Mantel-Cox) 0.832). Shunt survival at 3, 6, 12 and 30months was 60.6, 51.5, 36.4 and 27.3%, respectively, for VA and 56.3, 43.8, 37.5 and 37.5% for VPL shunts (log rank (Mantel-Cox) test value 0.727). The infection rate was 13.8% for VA and 5.6% for VPL shunts (p = 0.358). Four patients with VPL shunts (22.2%) developed pleural effusions. Fourteen deaths (25.9%) were recorded during follow-up, 8 (22.2%) in the VA and 6 (33.3%) in the VPL group (p= 0.380); two of the deaths in the VA group were shunt-related. This study demonstrates that the outcomes of VA and VPL shunts, when used as second-line surgical treatment in paediatric hydrocephalus, were similar, as were the revision, infection and survival rates. The shorter longevity of these shunts compared with the general shunted population may reflect the complex nature of these children.

Technical Nuances of Ventriculoatrial Shunt Using Seldinger Technique for Percutaneous Insertion of Distal Shunt Catheter

Abstract Introduction One of the most seen neurosurgical complications is the ventriculoperitoneal (VP) shunt failure. The cause can be often due to peritoneal malabsorption of cerebrospinal fluid. The next safer alternative is to place a ventriculoatrial (VA) shunt. Various methods of access to the right atrium had been described. The percutaneous method of insertion of distal catheter using Seldinger technique is a safer alternative to open method. We describe the percutaneous insertion of distal catheter using Seldinger technique, modifications in the method, and specific tools required for the insertion. Clinical History The patient is a 22-year-old male who is a known case of tubercular meningitis with recurrent failure of VP shunt due to malabsorption at peritoneal end of catheter. During the last hospital visit, he presented with altered sensorium and computed tomography scan brain showed ventriculomegaly. He was planned for VA shunt placement. Surgical Technique The insertion of ventricular end of the catheter is similar to any other shunt placement. The internal jugular vein (IJV) was punctured using introducer needle and guide wire was placed in the IJV at the level of T6-T7 and the serial dilators passed on the guide wire for creating a track for passage of shunt catheter. The shunt catheter was passed over the guide wire to the desired vertebral level and distal shunt catheter is connected proximally to the shunt catheter in the neck. Conclusion The percutaneous insertion of distal catheter with serial dilators using Seldinger technique is a safe and effective method for VA shunt placement.

Ultrasound-guided percutaneous brachiocephalic vein cannulation for ventriculoatrial shunt placement in a child.

As far as the ventriculoatrial shunt placement in children is concerned, the percutaneous approach to the internal jugular vein under ultrasonographic control has been hitherto strongly recommended. Unfortunately, children still represent a challenge, having them peculiar characteristics for which the internal jugular vein cannulation shows some disadvantages. In this manuscript, we describe a percutaneous placement of ventriculoatrial shunt via right brachiocephalic vein under intraoperative ultrasonographic control. Brachiocephalic vein cannulation in surgery provides notable advantages in paediatric population and it may be considered as the first choice in younger children.

Magnetic Resonance Imaging Findings of Idiopathic Normal Pressure Hydrocephalus and Cognitive Function Before and After Ventriculoatrial Shunt.

Background:The idiopathic normal pressure hydrocephalus (iNPH) is characterized by the triad of gait impairment, incontinence, and dementia. Cases that do not comply with the diagnostic criteria of ventriculomegaly have increased. It has led to the questions about the current criteria of guidelines. As the number of patients with dementia increases with aging, iNPH is importantly placed as a treatable dementia. The purpose of this study was to verify the validity of radiological diagnostic criteria of ventriculomegaly in iNPH.Materials and Methods:A board-certified neuroradiologist retrospectively examined 80 patients with definite iNPH about magnetic resonance imaging (MRI) findings of Evans index (EI) and disproportionately enlarged subarachnoid space hydrocephalus (DESH). The score of mini-mental state examination (MMSE) was measured to represent the cognitive function. The presurgical score of MMSE (pre-MMSE) and postsurgical best score of MMSE (best-MMSE) were compared statistically between patients dichotomized by either EI >0.3 or DESH.Results:The pre-MMSE was not different regardless of dichotomization by EI >0.3 or DESH. The MMSE score (median) increased significantly (P < 0.0001) by shunt from 20.0 to 26.0 in patients with EI >0.3 and from 21.5 to 25.5 with EI ≤0.3. No difference in the best-MMSE was observed between EI >0.3 and EI ≤0.3. The MMSE score increased significantly (P < 0.0001) by shunt from 21 to 27.5 with DESH and from 20 to 24.5 with non-DESH. Regardless of fulfilling or notfulfilling Japanese radiological diagnostic criteria (combination of EI >0.3 and DESH), cognitive function was significantly (P < 0.0001) improved to the same level. Only 24 cases (30%) fulfilled Japanese radiological diagnostic criteria.Conclusion:Cognitive function of iNPH patients was significantly improved by shunt regardless of MRI-findings. Radiological diagnostic criteria of iNPH may need careful reconsideration.