Intracranial ventricular shunts.

Permanent shunt diversion of cerebrospinal fluid away from the central nervous system is a widely recognized neurosurgical procedure. Still, patients with ventricular shunts are at substantial risk of shunt dysfunction, which includes complications like mechanical shunt failure, abnormal shunt drainage and infection. Early detection of shunt dysfunction is essential to proper and timely treatment, and acute shunt dysfunction might require immediate intervention. This review summarizes current and potential strategies for investigation of shunt dysfunction.

Freezing of gait in idiopathic normal pressure hydrocephalus.

BACKGROUND: Reports of freezing of gait (FoG) in idiopathic normal pressure hydrocephalus (iNPH) are few and results are variable. This study's objective was to evaluate the frequency of FoG in a large cohort of iNPH patients, identify FoG-associated factors, and assess FoG's responsiveness to shunt surgery. METHODS: Videotaped standardized gait protocols with iNPH patients pre- and post-shunt surgery (n = 139; median age 75 (71-79) years; 48 women) were evaluated for FoG episodes by two observers (Cohens kappa = 0.9, p < 0.001). FoG episodes were categorized. Mini-mental state examination (MMSE) and MRI white matter hyperintensities (WMH) assessment using the Fazekas scale were performed. CSF was analyzed for Beta-amyloid, Tau, and Phospho-tau. Patients with and without FoG were compared. RESULTS: Twenty-two patients (16%) displayed FoG at baseline, decreasing to seven (8%) after CSF shunt surgery (p = 0.039). The symptom was most frequently exhibited during turning (n = 16, 73%). Patients displaying FoG were older (77.5 vs. 74.6 years; p = 0.029), had a slower walking speed (0.59 vs. 0.89 m/s; p < 0.001), a lower Tinetti POMA score (6.8 vs. 10.8; p < 0.001), lower MMSE score (21.3 vs. 24.0; p = 0.031), and longer disease duration (4.2 vs. 2.3 years; p < 0.001) compared to patients not displaying FoG. WMH or CSF biomarkers did not differ between the groups. CONCLUSIONS: FoG is occurring frequently in iNPH patients and may be considered a typical feature of iNPH. FoG in iNPH was associated with higher age, longer disease duration, worse cognitive function, and a more unstable gait. Shunt surgery seems to improve the symptom.

[Preoperative Predictors of Outcomes of Cerebrospinal Fluid Shunt Surgery in Patients with Idiopathic Normal Pressure Hydrocephalus].

The disproportionately enlarged subarachnoid space hydrocephalus (DESH) findings on cranial images are useful to predict cerebrospinal fluid (CSF) shunt responsiveness to some extent in patients with idiopathic normal-pressure hydrocephalus (iNPH). However, recent studies show that patients with iNPH often have concomitant Alzheimer's or Lewy body disease regardless of DESH findings, which may be associated with poor outcomes of CSF shunt surgery. Moreover, long-term outcomes after CSF shunt surgery in patients with iNPH, which is one of the most important issues to be addressed for effective treatment of iNPH, remain unknown.

Techniques to Reduce the Rate of Infection in Surgeries for Cerebrospinal Fluid Shunting in Adults.

OBJECTIVE: Cerebrospinal fluid shunt placement is associated with high rates of infection. Multiple standardized protocols, particularly in pediatric populations, have been proposed to mitigate this infection rate. We sought to determine the effectiveness of a standardized shunt infection protocol in a large adult population. METHODS: A retrospective cohort study of adults presenting for primary cerebrospinal fluid shunt placement from 2012 to 2022. The primary outcome of interest was shunt infection. The primary exposure of interest was implementation of the shunt protocol (began October 2015). Secondary exposures of interest included use and type of perioperative antibiotics and total operating room time. RESULTS: In total, 820 patients were included, 140 before protocol implementation and 680 after protocol implementation. The overall number of infections over the study period was 15 (1.8% infection rate), with 8 infections preprotocol (5.7%) and 7 infections during the protocol period (1.0%). The infection protocol was associated with a decreased infection rate (odds rato [OR] 0.18, 95% confidence interval [CI] 0.05-0.58, P = 0.002). Total operating room time (OR 1.38 per 30-minute increase, 95% CI 1.05-1.81, P = 0.021) was associated with increased infection rate. Patients who received antibiotics with primarily gram-positive coverage (cefazolin or equivalent) did not have significantly different odds of shunt infection as patients who received broad-spectrum coverage (OR 2.10, 95% CI 0.56-7.88, P = 0.274). CONCLUSIONS: The implementation of an evidence-based perioperative shunt infection protocol is an effective method to decrease shunt infections. Broad-spectrum perioperative antibiotics may not have greater efficacy than gram-positive only coverage, but more research is required.

Normal pressure hydrocephalus, or Hakim syndrome: review and update.

This review makes the case that idiopathic normal pressure hydrocephalus (iNPH) is an outdated term because new information indicates that the syndrome is less idiopathic and that the cerebrospinal fluid (CSF) pressure of normal individuals is affected by several factors such as body mass index, age, and sex. Our review updates the epidemiology of iNPH and provides a clinical approach to the management of these patients. All the clinical features of iNPH are common in older individuals, and each has many causes, so the diagnosis is difficult. The first step in reaching an accurate diagnosis is to address the possible contributory factors to the gait abnormality and determine what if any role iNPH may be playing. The two best diagnostic tests are neuroimaging and cerebrospinal fluid (CSF) diversion (large volume lumbar puncture or external lumbar drainage) with pre/post gait evaluation. This review provides an update on the growing evidence that vascular disease, impaired CSF absorption, congenital, and genetic factors all contribute to the pathogenesis of iNPH. We suggest replacing the term iNPH with the term Hakim syndrome (HS) in acknowledgement of the first person to describe this syndrome. Lastly, we discuss the improvements in shunt technology and surgical techniques that have decreased the risks and long-term complications of shunt surgery.

A tailored approach to the management of post-haemorrhagic hydrocephalus.

PURPOSE: Neuro-endoscopic lavage (NEL) is an increasingly popular intervention for intraventricular haemorrhage (IVH) and post-haemorrhagic hydrocephalus (PHH), with considerable variation in technique dependent on clinician and clinical circumstances. Whilst efforts to standardise the technique are ongoing, this work describes a tertiary centre experience utilising NEL, highlighting potential caveats to standardisation. METHODS: A retrospective review of electronic case notes for patients undergoing temporising surgical intervention for IVH between 2012 and 2021 at our centre was performed. Data collected included (i) gestational age, (ii) aetiology of hydrocephalus, (iii) age at time of intervention, (iv) intervention performed, (v) need for permanent CSF diversion, (vi) 'surgical burden', i.e. number of procedures following primary intervention, and (vii) wound failure and infection rate. Data was handled in Microsoft Excel and statistical analysis SPSS v27.0 RESULTS: 49 neonates (n = 25 males) were included. Overall mean gestational age was 27 weeks and at intervention 35 + 3 weeks. IVH was the predominant cause of hydrocephalus (93.8%) and primary surgical interventions included insertion of a ventriculosubgaleal shunt (VSGS) in n = 41 (83.6%) patients, NEL in n = 6 (12.2%) patients and insertion of an EVD in n = 2 (4.1%). N = 9 (18.4%) patients underwent NEL at some point during the time interval reviewed; n = 4 (8.2%) received NEL monotherapy and n = 5 (10.2%) also received a VSGS. Rate of conversion to definitive CSF diversion between NEL (n = 8, 88.9%) and VSGS cohorts (n = 37, 92.5%) was not significantly different (p = 0.57), nor between NEL alone (n = 3, 75%) and NEL + VSGS (n = 5, 100%) (p = 0.44). None of the patients that underwent NEL monotherapy had any wound issues or CNS infection as a result of the initial intervention, compared to n = 3 (60%) of those that underwent NEL and implantation of VSGS (p = 0.1). CONCLUSION: Both NEL and VSGS are effective in temporising hydrocephalus in neonates, occasionally offering a definitive solution in and of themselves. The benefit of dual therapy however remains to be seen, with the addition of VSGS potentially increasing the risk of wound failure in an already vulnerable cohort.

Invasive Preoperative Investigations in Idiopathic Normal Pressure Hydrocephalus: A Comprehensive Review.

Idiopathic normal pressure hydrocephalus (iNPH) is a neurological disorder characterized by the triad of gait disturbance, cognitive impairment, and urinary incontinence. The condition is diagnosed mainly in older adults and is associated with ventricular enlargement without an increase in cerebrospinal fluid pressure. The clinical assessment involves a detailed medical history, physical examination, and cognitive testing. Neuroimaging is an essential part of the diagnostic workup for iNPH. However, to determine the suitability of patients for shunt surgery, a range of invasive preoperative investigations are employed. This narrative review aims to provide a comprehensive analysis of the current literature on invasive preoperative investigations in iNPH, focusing primarily on the lumbar infusion test, cerebrospinal fluid drainage tests, and continuous intracranial pressure monitoring. The strengths and limitations of each method, as well as their potential impact on treatment outcomes, are discussed.

Polyvinylpyrrolidone-coated catheters decrease choroid plexus adhesion and improve flow/pressure performance in an in vitro model of hydrocephalus.

PURPOSE: Proximal catheter obstruction is the leading cause of ventricular shunt failure in pediatric patients. Our aim is to evaluate various types of shunt catheters to assess in vitro cellular adhesion and obstruction. METHODS: Four catheter types were tested: (1) antibiotic and impregnated, (2) barium-stripe polyvinylpyrrolidone coated (PVP), (3) barium-stripe, and (4) barium-impregnated. Catheters were seeded with choroid plexus epithelial cells to test cellular adhesion and inoculated with the same cells to test flow/pressure performance under choroid plexus growth conditions. Ventricular catheters were placed into a three-dimensional printed phantom ventricular replicating system through which artificial cerebrospinal fluid (CSF) was pumped. Differential pressure sensors were used to measure catheter performance. RESULTS: PVP catheters had the lowest median cell attachment (10 cells) compared to antibiotic-impregnated (230 cells), barium stripe (513 cells), and barium-impregnated (146 cells) catheters after culture (p < 0.01). In addition, PVP catheters (- 0.247 cm H2O) and antibiotic-impregnated (- 1.15 cm H2O) catheters had significantly lower pressure in the phantom ventricular system compared to the barium stripe (0.167 cm H2O) and barium-impregnated (0.618 cm H2O; p < 0.01) catheters. CONCLUSIONS: PVP catheters showed less cellular adhesion and, together with antibiotic-impregnated catheters, required less differential pressure to maintain a consistent flow. Our findings suggest clinical relevance for using PVP ventricular catheters in patients with recurrent catheter obstruction by choroid plexus.

Radionuclide shuntography for cerebrospinal fluid shunt flow evaluation in adults.

OBJECTIVE: Radionuclide shuntography (RS) performed using 99mTc-DTPA injected into the reservoir of CSF shunts enables evaluation of CSF flow for suspected shunt malfunctions. The goal of this study was to report the authors' institutional experience with RS and evaluate its utility and associated complications. METHODS: The authors retrospectively reviewed all RS studies performed between November 2003 and June 2022. Patients with shunted hydrocephalus who were ≥ 18 years of age were included. Patients undergoing RS for evaluation of Ommaya reservoirs were excluded. Demographics, hydrocephalus etiology, presenting symptoms, study results, subsequent management, complications, and intraoperative diagnoses were recorded. Chi-square tests were reported for categorical variables and standard 2 × 2 contingency methods were used for sensitivity/specificity analysis. RESULTS: The authors identified 211 RS procedures performed in 142 patients. The mean age at procedure was 55.6 ± 20.9 years (mean ± SD). Normal pressure hydrocephalus was the most common hydrocephalus etiology (37.0%), followed by congenital malformations (26.1%) and idiopathic intracranial hypertension (15.6%). Successful radionuclide injection was achieved in 207 studies (98.1%). Shunt patency was confirmed in 63.8% of successful injections, whereas malfunction was demonstrated in 27.1% and abnormally slow flow was seen in 9.2%. RS studies demonstrating shunt malfunction were more likely to result in subsequent revisions than were studies showing patency (86.6% vs 2.9%; p < 0.0001). The overall sensitivity and specificity of RS for detecting shunt malfunction was 92.3% and 96.2%, respectively. The median follow-up time was 29 months, with 151 cases having ≥ 6 months of follow-up. There were no complications or infections attributable to RS in this cohort. CONCLUSIONS: RS is a useful and safe tool in the workup of shunt malfunction.

The Long-Term Patency of the Internal Jugular Vein and the Common Facial Vein as Entrance Sites for Venous Access in Ventriculoatrial Shunts: A Comparative Analysis from a Single-Center Study.

OBJECTIVE: The ventriculoatrial (VA) shunt is a surgical intervention used to manage hydrocephalus, although it is less often utilized compared to the ventriculoperitoneal (VP) shunt or endoscopic third ventriculostomy. Placement of the distal catheter typically involves the utilization of either the common facial vein (CFV) or the internal jugular vein (IJV), 2 frequently employed options for venous access. This study aims to determine whether there is a statistically significant difference between the long-term patency (2 years) of the distal end of the VA shunt of these 2 options. METHODS: A retrospective cohort analysis was conducted of patients who received VA shunt surgeries with the employment of the CFV or IJV as access veins at Rajavithi Hospital in Thailand between January 2015 and December 2020. The analysis focused on long-term patency and potential complications. RESULTS: The study comprised a total of 42 participants. Twenty-six (61.9%) individuals underwent ventriculoatrial (VA) shunt surgery via the CFV, while the other 16 (38.1%) underwent the same procedure using the IJV. Neither of the 2 groups required shunt revision due to distal catheter malfunction. Most cases exhibited no significant complications apart from a single instance of shunt system infection. CONCLUSIONS: In VA shunt surgery, both the CFV and IJV can be used as venous access sites for the right atrium because there is no discernible difference between their complications or long-term patency. Anatomical considerations, patient-specific characteristics, and the surgeon's preference should all be considered when choosing the venous access location for the placement of a VA shunt.

Successful Implantation of a Ventricular Shunt With Termination in the Iliac Bone in the Adult Patient With Obstructive Hydrocephalus.

BACKGROUND AND IMPORTANCE: With the exception of the 3 classic shunt placement options (ventriculoperitoneal, ventriculopleural, and ventriculoatrial), surgically feasible alternative sites for distal catheter placement remain limited and often require the assistance of an access surgeon. Tubbs et al suggested the possibility of intraosseous cerebrospinal fluid diversion in the ilium, noting that ilium infusion in cadaveric specimens was possible without the development of body edema or fluid overflow. Since this publication, limited case reports have been published on the success of ventriculo-ilium (VI) shunt placement. Here, we describe the technique used for successful VI shunt placement in 2 adult patients. CLINICAL PRESENTATION: Here, we describe 2 patients with differing etiologies of hydrocephalus (obstructive and nonobstructive) and complex medical and surgical problems precluding traditional distal shunt termini. Both patients underwent successful placement of a VI shunt with distal catheter placement into the right iliac crest using a small right-angle connector and small cranial fixation plate to prevent backout of the catheter. DISCUSSION AND CONCLUSION: We report the first demonstration of successful placement of a VI shunt in 2 adult patients with evidence of shunt functionality and improved neurological outcome. We propose that the placement of a VI shunt is an easy and viable option when more traditional shunt methods are not available for use.

A novel, benchtop model for quantitative analysis of resistance in ventricular catheters.

INTRODUCTION: The mechanisms of catheter obstruction are still poorly understood, but the literature suggests that resistance to fluid flow plays a significant role. We developed and assessed a gravity-driven device that measures flow through ventricular catheters. We used this device to quantitatively analyze the resistances of unused ventricular catheters used in the treatment of hydrocephalus; failed hydrocephalus catheters from our catheter biorepository were also evaluated quantitatively. METHODS: Catheters of three manufacturing companies were inserted into the benchtop model, which records time, flow rate, and pressure data using sensors. The relative resistances of catheters across six design models were evaluated. Experiments were performed to evaluate changes in the relative resistance of a catheter when the catheter's holes were progressively closed. The relative resistance of explanted catheters from our catheter biorepository was also measured. RESULTS: Experimental results showed significant differences (P<0.05) between the relative resistances of different catheter models just after being removed from their packaging. A non-linear trend of increasing resistance was observed in experiments on catheters with artificially obstructed holes. Data from five individual benchtop models were compared, and the differences in measured data between the models were found to be negligible. A significant increase (P < 0.05) in relative resistance was observed in explanted catheters. CONCLUSION: The current study sought to propose a novel in-vitro model and use it to examine data on differences in relative resistance among catheter models. From these experiments, we can rapidly correlate clinical patient cohorts to identify mechanisms of luminal shunt obstruction.

Association of gait and cognition after surgery in patients with idiopathic normal pressure hydrocephalus.

Idiopathic normal pressure hydrocephalus (iNPH) is a treatable disease in older adults. The association between gait and cognition has recently become a topic of interest. Sequential changes in this association were investigated in patients with iNPH using a newly developed statistical method. Data were extracted from the SINPHONI-2 multicenter study on iNPH. Fifty patients who underwent shunt surgery were included in this study. Gait and cognition were assessed using the Timed Up and Go (TUG) and Mini-Mental State Examination (MMSE) tests. In addition to the MMSE total score, changes in the sub-item scores were examined. The ordinal sub-items of the MMSE are usually treated as continuous or categorical; however, both are unsuitable. An ordinal smoothing penalty with a generalized additive model enables precise statistical inference of ordinal and binary predictors. The TUG time improved significantly at 3, 6, and 12 months after surgery. The MMSE total scores increased without statistical significance. Preoperatively, there was no association between TUG time and MMSE sub-items. At 3 months, the "Registration," "3-step command," "Read," and "Copy" sub-items were statistically significant. The number of significant sub-items increased after 12 months. Thus, the association between gait and cognition gradually increased after surgery in patients with iNPH.

Safety and function of programmable ventriculo-peritoneal shunt valves: An in vitro 7 Tesla magnetic resonance imaging study.

OBJECTIVE: The quantity of ultra-high field MRI neuroimaging studies has rapidly increased. This study tests function, safety, and image artifacts of two frequently implanted programmable ventriculo-peritoneal (VP) shunt valves in a 7T MRI system. METHODS: All tests were performed using a whole-body 7T MRI system. Three proGAV 2.0 and 3 CODMAN CERTAS® Plus programmable VP-shunt valves were tested in three steps. 1) Deflection angle tests close to the bore opening at the location of a static magnetic field gradient of 3-5 T/m. 2) Valves were fixed on a spherical phantom in 3 positions (a. lateral, b. cranial, c. cranial with 22.5° tilt anteriorly) and assessed for keeping the programmed pressure setting and reprogrammability. 3) Valves were fixed on the phantom and positioned lateral in a radiofrequency head coil. MRI scans were performed for both models, including MPRAGE, GRE and SE sequences. RESULTS: Deflection angles were moderate (13°, 14°, 13°) for the proGAV valves and close to critical (43°, 43°, 41°) for the CODMAN valves at the test location. Taking a scaling factor of 2-3 for the maximum spatial magnetic field gradient accessible to a patient within the magnet bore into account renders both valves MR unsafe regarding ferromagnetic attraction. The proGAV valves kept the pressure settings in all positions and were reprogrammable in positions a. and b. In position c., reprogrammability was lost. The CODMAN valves changed their pressure setting and reprogrammability was lost in all positions. MR image signal homogeneity was unaltered in the phantom center, artifacts limit the assessability of structures in close vicinity to the valves. CONCLUSION: Both tested programmable VP-shunt valves are MR unsafe for 7T systems. Novel programming mechanisms using permanent magnets with sufficient magnetic coercivity or magnet-free mechanisms may allow the development of programmable VP-shunt valves that are conditional for 7T MR systems.

Ventriculosubgaleal shunts in the management of neonatal post-haemorrhagic hydrocephalus: technical note.

INTRODUCTION: Germinal matrix / intraventricular haemorrhage (GMIVH) remains a significant complication of prematurity. The more severe grades are associated with parenchymal haemorrhagic infarction (PHI) and hydrocephalus. A temporising procedure is usually the first line in management of neonatal post-haemorrhagic hydrocephalus (nPHH) as the risk of failure of a permanent cerebrospinal fluid (CSF) diversion is higher in the early stage. Our choice of temporising procedure is a ventriculosubgaleal shunt (VSGS). In this technical note, we describe a modification in technique whereby the pocket of the VSGS is fashioned away from the surgical wound. This resulted in lower CSF leak and subsequent infection rates in our centre. METHODS: We conducted a retrospective analysis of all patients who underwent insertion of a VSGS between September 2014 and February 2023. RESULTS: Twenty children were included in our study with a mean gestational age of 31 weeks + 4 days. Post-operatively, 10% of patients did not need a tap, and 10%, 20%, 15%, 25% and 20% respectively had 1, 2, 3, 4 and 5 taps. Two patients experienced CSF leak from their wounds. In both these patients, the pocket was deemed too close to the wound. None of the patients without suspected pre-existing CNS infection at the time of insertion of VSGS had a subsequent VSGS-related infection. VSGS conversion to permanent ventriculoperitoneal shunts (VPS) was required in 15 (75%) of the patients with an average interval duration of 72 days. On reviewing the literature, the infection rate following VSGS is quoted up to 13.5%. In our own centre, 13 patients had undergone VSGS insertion between 2005 and 2013 with a 30.8% infection rate which seemed related to increased leak rates. CONCLUSION: Our modified surgical approach seems to be effective in reducing the risk of infection, which we postulate is a direct result of reduction in the risk of leak from the surgical wound.

Long-term follow-up and comparison of programmable and non-programmable ventricular cerebrospinal fluid shunts among adult patients with different hydrocephalus etiologies: a retrospective cohort study.

BACKGROUND: Programmable valve (PV) has been shown as a solution to the high revision rate in pediatric hydrocephalus patients, but it remains controversial among adults. This study is to compare the overall revision rate, revision cause, and revision-free survival between PV and non-programmable valve (NPV) in adult patients with different hydrocephalus etiologies. METHOD: We reviewed the chart of all patients with hydrocephalus receiving index ventricular cerebrospinal fluid (CSF) shunt operations conducted at a single institution from January 2017 to December 2017. Patients included in the study were followed up for at least 5 years. Statistical tests including independent t-test, chi-square test, and Fisher's exact test were used for comparative analysis, and Kaplan-Meier curve using log-rank test was performed to compare the revision-free survival between the PV and NPV groups. RESULTS: A total of 325 patients were included in the study, of which 181 patients were receiving PVs and 144 patients receiving NPV. There were 23 patients (12.8%) with PV and 22 patients (15.3%) with NPV receiving initial revision. No significant statistical difference in the initial revision rate was observed between the two groups (p = 0.52). No survival difference was found between the PV and NPV groups. However, better revision-free survival was noted in the PV group among idiopathic normal pressure hydrocephalus (iNPH) (p = 0.0274) and post-traumatic hydrocephalus (p = 0.017). CONCLUSIONS: The combination of the different etiologies of hydrocephalus and the features of PV and NPV results in different outcomes-revision rate and revision-free survival. PV use might be superior to NPV in iNPH and post-traumatic hydrocephalus patients. Further studies are needed to clarify the indications of PV use in adult hydrocephalus patients.

Evaluation of Miethke M.scio Device Implantation for Intracranial Pressure Monitoring in Patients with Cerebrospinal Fluid Disorders.

BACKGROUND: Patients with complex shunt-related problems and varying diagnoses of cerebrospinal fluid (CSF) disturbance can present with headache and clinical symptoms that may be difficult to relate to underdrainage or overdrainage. Telemetric intracranial pressure (ICP) monitoring may assist in evaluating individual patients and assessing shunt function and adjustment. We report a case series of patients receiving a Miethke M.scio sensor. METHODS: Between June 2016 and August 2021, 14 patients older than 18 years with different diagnoses underwent ventriculoperitoneal shunt surgery and received a Miethke M.scio sensor. RESULTS: Patients had idiopathic intracranial hypertension (n = 3), obstructive hydrocephalus caused by tumors (n = 4), and malformations (n = 5). Headaches (71%) and visual impairment (50%) were the most common symptoms before surgery and 65% of the symptoms were improved after surgery. In total, 25 measurements were made and 11 of these led to changes in the shunt settings. Postoperative measurements were taken in 8 patients and the most common indication of ICP measurement was headache and/or control of the shunt settings. CONCLUSIONS: The Miethke M.scio is a safe and valuable device to use in shunt-treated patients, in particular those expected to need assessment of ICP monitoring postoperatively. Repeated ICP measurements can also assist in personalized adjustment of the shunt setting to optimize CSF flow in this diverse patient group. Future studies should include a standardized protocol with ICP measurements correlated to the symptoms and cause of CSF disturbances to provide better understanding of the dynamics of the ICP in each patient.

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.

Postoperative course of cerebrospinal fluid diversion in the setting of leptomeningeal disease: a systematic review, meta-analysis, and meta-regression with an illustrative case.

BACKGROUND: Management of hydrocephalus symptoms in the setting of leptomeningeal disease (LMD) includes cerebrospinal fluid (CSF) diversion, which can in the form of ventriculoperitoneal shunting (VPS) and lumboperitoneal shunting (LPS). However, the quantifiable postoperative course following this intervention is poorly defined. Correspondingly the aim of our study was to quantitatively define and analyze the pooled metadata regarding this topic. METHODS: Multiple electronic databases from inception to March 2023 were searched following PRISMA guidelines. Respective cohort-level outcomes were then abstracted and pooled by means of meta-analyses and analyzed by means meta-regression, both utilizing random-effects modeling. Post-hoc bias evaluation was then performed for all outcomes. RESULTS: A total of 12 studies were identified for inclusion, describing 503 LMD patients managed by CSF diversion - 442 (88%) by VPS and 61 (12%) by LPS. Median male percentage and age at diversion were 32% and 58 years respectively, with lung and breast cancer the most common primary diagnoses. Meta-analysis demonstrated pooled incidence of symptom resolution in 79% (95% CI 68-88%) of patients after index shunt surgery, and shunt revision required in 10% (95% CI 6-15%) of cases. Pooled overall survival from index shunt surgery was 3.8 mo (95% CI 2.9-4.6 mo) across all studies. Meta-regression demonstrated that studies published later trended towards significantly shorter overall survival from index shunt surgery (co-efficient=-0.38, P = 0.023), whereas the proportion of VPS to LPS in each study did not impact survival (P = 0.89). When accounting for these biases, overall survival from index shunt surgery was re-estimated to be shorter 3.1 mo (95% CI 1.7-4.4 mo). We present an illustrative case demonstrating the course of symptom improvement, shunt revision and an overall survival of 2 weeks from index CSF diversion. CONCLUSION: Although CSF diversion in the setting of LMD can improve hydrocephalus symptoms in the majority of patients, there is a non-negligible proportion that will require shunt revision. Postoperatively, the prognosis of LMD remains poor irrespective of shunt type, and despite possible biases within the current literature, the expected median overall survival after index surgery is a matter of months. These findings support CSF diversion as an effective palliative procedure when considering symptoms and quality of life. Further research is required to understand how postoperative expectations can be managed to respect the best wishes of patients, their family, and the treating clinical team.