Applied deep learning in neurosurgery: identifying cerebrospinal fluid (CSF) shunt systems in hydrocephalus patients.

BACKGROUND: Over the recent decades, the number of different manufacturers and models of cerebrospinal fluid shunt valves constantly increased. Proper identification of shunt valves on X-ray images is crucial to neurosurgeons and radiologists to derive further details of a specific shunt valve, such as opening pressure settings and MR scanning conditions. The main aim of this study is to evaluate the feasibility of an AI-assisted shunt valve detection system. METHODS: The dataset used contains 2070 anonymized images of ten different, commonly used shunt valve types. All images were acquired from skull X-rays or scout CT-images. The images were randomly split into a 80% training and 20% validation set. An implementation in Python with the FastAi library was used to train a convolutional neural network (CNN) using a transfer learning method on a pre-trained model. RESULTS: Overall, our model achieved an F1-score of 99% to predict the correct shunt valve model. F1-scores for individual shunt valves ranged from 92% for the Sophysa Sophy Mini SM8 to 100% for several other models. CONCLUSION: This technology has the potential to automatically detect different shunt valve models in a fast and precise way and may facilitate the identification of an unknown shunt valve on X-ray or CT scout images. The deep learning model we developed could be integrated into PACS systems or standalone mobile applications to enhance clinical workflows.

Treatment of wound infections linked to neurosurgical implants.

As neurosurgery has advanced technologically, more and more neurosurgical implants are being employed on an aging patient population with several comorbidities. As a result, there is a steady increase in the frequency of infections linked to neurosurgical implants, which causes serious morbidity and mortality as well as abnormalities of the skull and inadequate brain protection. We discuss infections linked to internal and external ventricular and lumbar cerebrospinal fluid drainages, neurostimulators, craniotomies, and cranioplasty in this article. Biofilms, which are challenging to remove, are involved in all implant-associated illnesses. It takes a small quantity of microorganisms to create a biofilm on the implant surface. Skin flora bacteria are implicated in the majority of illnesses. Microorganisms that cause disruptions in wound healing make their way to the implant either during or right after surgery. In about two thirds of patients, implant-associated infections manifest early (within the first month after surgery), whereas the remaining infections present later as a result of low-grade infections or by direct extension from adjacent infections (per continuitatem) to the implants due to soft tissue damage. Except for ventriculo-atrial cerebrospinal fluid shunts, neurosurgical implants are rarely infected by the haematogenous route. This research examines established and clinically validated principles that are applicable to a range of surgical specialties using implants to treat biofilm-associated infections in orthopaedic and trauma cases. Nevertheless, there is little evidence and no evaluation in sizable patient populations to support the success of this extrapolation to neurosurgical patients. An optimal microbiological diagnostic, which includes sonicating removed implants and extending culture incubation times, is necessary for a positive result. Additionally, a strategy combining surgical and antibiotic therapy is needed. Surgical procedures involve a suitable debridement along with implant replacement or exchange, contingent on the biofilm's age and the state of the soft tissue. A protracted biofilm-active therapy is a component of antimicrobial treatment, usually lasting 4-12 weeks. This idea is appealing because it allows implants to be changed or kept in place for a single surgical procedure in a subset of patients. This not only enhances quality of life but also lowers morbidity because each additional neurosurgical procedure increases the risk of secondary complications like intracerebral bleeding or ischemia.

Current status and challenges of neurosurgical procedures for patients with myelomeningocele in real-world Japan.

BACKGROUND: Little is known about the real-world status of neurosurgical treatment of myelomeningocele patients. OBJECTIVE: To investigate the real-world status of neurosurgical treatment of myelomeningocele patients, medical claims data provided by the Japan Medical Data Center (JMDC) were analyzed. METHODS: The health claims data of 556 patients with myelomeningoceles from January 2005 to March 2020 were examined. The number of neurosurgical procedures, including myelomeningocele repair, tethered cord release, cerebrospinal fluid (CSF) shunt, CSF drainage, and endoscopic third ventriculostomy (ETV), was determined. RESULTS: A total of 313 neurosurgical procedures were performed for 135 patients in 74 institutions during the study period. The shunt survival rate was most affected by shunts that were revised when the patient was less than 1 year old, which had a significantly lower survival rate than all of the initial shunts performed when the patient was less than on1 year old; the 1-year shunt survival rate was 35 vs 64% (P = 0.0102). The survival rate was significantly lower in patients younger than 1 year who had CSF drainage before shunting compared to those younger than 1 year who did not have CSF drainage before shunting; the 1-year shunt survival rate was 27 vs 59% (P = 0.0196), and 81% of patients remained free of tethered cord release 10 years later. CONCLUSIONS: In this study, a revised shunt of less than 1 year of age and CSF drainage before shunting were the factors that lowered the shunt survival rate in the real world for CSF shunts for hydrocephalus associated with myelomeningocele.

Adjustable shunts and proton therapy: a magnetic combination.

OBJECTIVE: Due to evidence for proton beam therapy (PBT) in pediatric central nervous system (CNS) tumors, compact proton therapy systems became commercially available to allow better integration in a hospital setting. However, these systems have a non-zero magnetic field at the level of the patient. Often, these patients have a cerebrospinal fluid shunt, and most of them are adjustable through a magnet. Whether the induced magnetic fields could interfere with adjustable shunts is unknown. METHODS: In the first five CNS tumor patients with adjustable shunts who underwent PBT, the shunt setting was controlled before, during, and after treatment with PBT. Additionally, we used an ex vivo adjustable shunt to check if the settings could be altered by the magnetic field. RESULTS: We did not observe unintentional changes in shunt settings in vivo during treatment. In ex vivo testing, the shunt settings were altered directly cranial to the exit window of PBT due to the magnetic field. CONCLUSION: Although we did not observe any shunt setting alteration during PBT in this small cohort, caution is warranted. Given the lack of high-volume data, there should be a low threshold for checking the shunt setting at the end of PBT therapy or in a symptomatic patient.

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.

Risk factors for shunting at 12 months following open fetal repair of spina bifida by mini-hysterotomy.

OBJECTIVES: Open spina bifida (OSB) is the most common neural tube defect. Prenatal repair reduces the need for ventriculoperitoneal shunting (VPS) due to hydrocephalus from 80-90% to 40-50%. We aimed to determine which variables work as risk factors for VPS at 12 months of age in our population. METHODS: Thirty-nine patients underwent prenatal repair of OSB by mini-hysterotomy. The main outcome was occurrence of VPS in the first 12 months of life. Logistic regression was used to estimate the odds ratios (OR) between prenatal variables and the need for shunting. RESULTS: VPS at 12 months occurred in 34.2% of the children. Larger ventricle size before surgery (62.5% ≥15 mm; 46.2% between 12 and 15 mm; 11.8% <12 mm; p=0.008), higher lesion level (80% >L2, vs. 17.9% ≤L3; p=0.002; OR, 18.4 [2.96-114.30]), and later gestational age at surgery (25.25 ± 1.18 vs. 24.37 ± 1.06 weeks; p=0.036; OR, 2.23 [1.05-4.74]) were related to increased need for shunting. In the multivariate analysis, larger ventricle size before surgery (≥15 mm vs. <12 mm; p=0.046; OR, 1.35 [1.01-1.82]) and higher lesion level (>L2 vs. ≤L3; p=0.004; OR, 39.52 [3.25-480.69]) were risk factors for shunting. CONCLUSIONS: Larger ventricle size before surgery (≥15 mm) and higher lesion level (>L2) are independent risk factors for VPS at 12 months of age in fetuses undergoing prenatal repair of OSB by mini-hysterotomy in the studied population.

Just Stick a Scope in: Laparoscopic Ventriculoperitoneal Shunt Placement in the Pediatric Reoperative Abdomen.

BACKGROUND: Ventriculoperitoneal shunt (VPS) placement into the reoperative abdomen can be challenging due to intraperitoneal adhesions. Laparoscopic guidance may provide safe abdominal access and identify an area for optimal cerebrospinal fluid drainage. The study aim was to compare laparoscopic-assisted VPS placement to an "open" approach in patients with prior abdominal surgery. MATERIALS AND METHODS: A retrospective review was performed of children undergoing VPS placement into a reoperative abdomen from 2009-2019. Clinical data were collected, and patients undergoing laparoscopy (LAP) were compared to those undergoing an open approach (OPEN). RESULTS: A total of 120 children underwent 169 VPS placements at a median age of 8 y (IQR 2-15 y), and a mean number of two prior abdominal operations (IQR 1-2). Laparoscopy was used in 24% of cases. Shunt-related complications within 30 d were lower in the LAP group (0% versus 19%, P = 0.001), as were VPS-related postoperative emergency department visits (0% versus 13%, P = 0.003) and readmissions (0% versus 13%, P = 0.013). Shunt malfunction rates were higher (42% OPEN versus 25% LAP, P = 0.03) and occurred sooner in the OPEN group (median 26 versus 78 wk, P = 0.01). The LAP group demonstrated shorter operative times (63 versus 100 min, P < 0.0001), and the only bowel injury. Time to feeds, length of stay, and mortality were similar between groups. CONCLUSIONS: Laparoscopic guidance during VPS placement into the reoperative abdomen is associated with a decrease in shunt-related complications, longer shunt patency, and shorter operative times. Prospective study may clarify the potential benefits of laparoscopy in this setting.

Mechanical complications of cerebrospinal fluid shunt. Differences between adult and pediatric populations: myths or reality?

OBJECTIVE: Shunt malfunctions seem more frequent in children (44 to 81%) than in adults (18 to 29%). Because of discrepancies between studies, it is not possible to affirm this disparity. The objective was to verify whether the incidence of cerebrospinal fluid (CSF) shunt malfunctions is higher in children than adults. METHODS: We present a retrospective series of child and adult patients who underwent CSF shunt placement between 2000 and 2013 with a Sophysa SM8® valve. RESULTS: 599 adults and 98 children (sex ratio 1.28) underwent CSF shunt placement. Age at first surgery ranged between 1 day of life and 90 years (mean of 55.8 years, SD 25.8, median 64.8 years). The mean follow-up was 4 years (SD 4.264, 0-16; median 3 years). The cumulative complication rate was 25.5% (178/697). Mechanical complications were disconnection (25.1%), migration (11.8%), intracranial catheter obstruction (8.9%) and malposition (8.4%). The mean delay for the first revision was 1.90 years (0-13.9), (SD 2.73, median 0.5). The probability of shunt failure was 65% at 10 years in the child group and 36% at 10 years in the adult group. Moreover, in the child group, 33% of revisions occurred during the first year after shunt placement versus 17% in the adult group. Thus, the probability of shunt failure was higher in children than in adults (log-rank test, p < 0.001). CONCLUSIONS: This is the first retrospective study, comparing children and adults undergoing CSF shunt using the same valve, able to confirm the higher rate of complications in children.

Shunt dependency syndrome and acquired Chiari malformation secondary to cerebrospinal fluid diversion procedures: a 9-year longitudinal observation.

BACKGROUND: Shunt dependency syndrome is a rare long-term complication of cystoperitoneal (CP) shunting for intracranial arachnoid cysts, which is characterized by acute intracranial hypertension with normal-sized or small ventricles. Additionally, acquired Chiari type I malformations (ACIM) could be infrequently secondary to extrathecal shunt drainage of cerebrospinal fluid. CASE REPORT: We described a 12-year-old boy who developed shunt dependency syndrome following a CP shunting for treating a temporal arachnoid cyst. To manage this rare complication, we placed a lumboperitoneal (LP) shunt. During the follow-up period, shunt-induced ACIM and concomitant syringomyelia were noted. CONCLUSION: Shunt dependency syndrome is a rare complication secondary to CP shunting in the treatment of temporal arachnoid cysts, and LP shunting is an effective option to relieve the intracranial hypertension. However, the clinicians should be alert to the ACIM as a rare late complication of cerebrospinal fluid diversion procedures, and the potential protecting effect of the programmable valve should be emphasized.

Reviewing the prognostic factors in myelomeningocele.

OBJECTIVE: The goal of this study was to analyze the factors that have an impact on morbidity and mortality in patients with myelomeningocele (MMC). METHODS: A retrospective cohort study was conducted to analyze factors associated with MMC that influence the morbidity and mortality of the disease. Data were collected from medical records of children who underwent the primary repair of MMC at the Fernandes Figueira Institute-Oswaldo Cruz Foundation (IFF-Fiocruz) between January 1995 and January 2015, with a minimum follow-up of 1 year. The following variables were analyzed: demographic characteristics (gestational age, sex, and birth weight); clinical features (head circumference at birth, anatomical and functional levels of MMC, hydrocephalus, symptomatic Chiari malformation type II, neurogenic bladder, and urinary tract infection [UTI]); and surgical details such as timing of repair of MMC, age at first shunt placement, shunt surgery modality (elective or emergency), concurrent surgery (correction of MMC and shunt insertion in the same surgical procedure), incidence and cause of shunt dysfunction, use of external ventricular drain, transfontanelle puncture, surgical wound complications prior to shunting, and endoscopic treatment of hydrocephalus. RESULTS: A total of 231 patients with MMC were included in the analysis. Patients were followed for periods ranging from 1 to 20 years, with a mean of 6.9 years. The frequency of shunt placement was observed mainly among patients with MMC at the highest spinal levels (p < 0.01). The main causes of morbidity and mortality in patients with MMC were shunt failures, diagnosed in 91 of 193 cases (47.2%) of hydrocephalus, and repeated UTIs, in 129 of 231 cases (55.8%) of MMC; these were the main causes of hospitalization and death. Head circumference ≥ 38 cm at birth was found to be a significant risk factor for shunt revision (p < 0.001; 95% CI 1.092-1.354). Also, the lumbar functional level of MMC was associated with less revision than upper levels (p < 0.014; 95% CI 0.143-0.805). There was a significant association between recurrent UTI and thoracic functional level. CONCLUSIONS: Macrocephaly at birth and higher levels of the defect have an impact on worse outcome and, therefore, are a challenge to the daily practice of pediatric neurosurgery.

Effect of cerebrospinal fluid shunt surgery on lower urinary tract dysfunction in idiopathic normal pressure hydrocephalus.

AIMS: To examine the outcomes of lower urinary tract symptoms (LUTS) and urodynamic test results after cerebrospinal fluid (CSF) shunt surgery in idiopathic normal pressure hydrocephalus (iNPH). METHODS: Records of 48 patients (33 men; 15 women), who met the definite iNPH criteria and underwent CSF shunt surgery, were retrospectively analyzed. LUTS and their impact on quality of life (QOL) were evaluated using an all-or-none questionnaire targeting four symptoms, the Overactive Bladder Symptoms Score (OABSS), and the QOL index. Urodynamic investigations included filling cystometry and pressure-flow studies performed before and after surgery. RESULTS: Forty-seven (98%) patients complained of LUTS, 41 (87%) patients of whom experienced LUTS improvement after surgery. The OABSS and QOL index, which before surgery were 6.8 ± 0.7 and 4.1 ± 0.4, respectively, significantly decreased to 4.6 ± 0.6 and 3.2 ± 0.3, respectively, after surgery. The maximum cystometric capacity (174.9 ± 13.3 mL to 222.4 ± 14.7 mL) and bladder compliance (35.8 ± 4.4 ml/cmH2 O to 52.1 ± 5.4 ml/cmH2 O) significantly increased after surgery. Detrusor overactivity, which was observed in 37 (77%) patients preoperatively, became undetectable in 7 patients postoperatively. Voiding dysfunction (defined as maximum flow rate <10 mL/s or post-void residual >100 mL) was observed in 29 (60%) patients, 22 (75%) of whom had detrusor underactivity before surgery. None of the voiding urodynamic parameters significantly improved postoperatively. CONCLUSIONS: iNPH is often associated with LUTS and both storage and voiding dysfunctions. CSF shunt surgery improved LUTS and storage dysfunction, with limited effects on voiding dysfunction.

The applicability of fixed and adjustable gravitational shunt valves in two different clinical settings.

BACKGROUND: Gravitational shunt valves and most recently the adjustable proSA® gravitational valve have been designed to counteract overdrainage and thereby improving clinical outcome. So far, the applicability in a broader mix of hydrocephalus patients is unrevealed. The aim of this study was to evaluate the utility of gravitational valves in two different clinical settings. METHODS: This retrospective double-center cohort study was enabled by two different shunt management policies. At Rigshospitalet, patients with a complicated shunt history receiving a proGAV® and proSA® shunt system during surgical revision were included, and clinical outcome in the follow-up periods before and after was compared. At Aarhus University Hospital, a combination of a proGAV® and a fixed (SA®) or adjustable (proSA®) gravitational valve was used in all shunt procedures. Clinical outcome in a 2-year follow-up period was compared to a cohort receiving non-gravitational valves in the period before the transition to gravitational valves. RESULTS: Twenty-two patients were included at Rigshospitalet. Mean follow-up time before and after proGAV® and proSA® implantation was 2.3 and 1.5 years, respectively. In each patient, roughly two surgical revisions (p 0.031) and two hospitalizations (p 0.009) were avoided each year after proGAV® and proSA® implantation. At Aarhus University Hospital, 90 patients with non-gravitational valves and 98 patients with gravitational valves were included. Changes in clinical outcome parameters and shunt survivals were either stable or statistically insignificant. CONCLUSIONS: Gravitational valves are safe and useful in clinical practice and represent an equivalent alternative as a first-line shunt valve in a broad mix of patients, while proSA® valves should be considered for complex shunt patients.

Differential Pressure Shunt for Simultaneous Diversion of Ventricular Fluid and Extracerebral Fluid.

BACKGROUND/AIMS: The management of extracerebral collections of fluid in patients with hydrocephalus can be problematic for either their simultaneous separate management or sequential management, each of which may require multiple surgeries and the management of external drains. The object of this report is to review the experience with a shunt configuration that simultaneously diverts ventricular fluid and extracerebral fluid, whether subdural or subarachnoid in location, through different outflow resistances. METHODS: The medical records, including neuroimaging of patients with hydrocephalus and clinically significant extracerebral collections of low density who were managed by implanting a differential pressure type shunt, were retrospectively reviewed. RESULTS: Four patients, 3 children and 1 adult, met inclusion criteria. Three had the entire differential pressure shunt implanted under 1 anesthetic, and 1 had a catheter inserted into the subdural space and connected into an existing ventriculoperitoneal shunt system. The extracerebral fluid collections cleared in all 4 patients, and the CSF shunt continued to function normally. CONCLUSION: A single surgical procedure to implant a differential pressure shunt can simultaneously drain and obliterate an extracerebral fluid collection while managing the hydrocephalus. Compared to routines that include external drainage, differential pressure shunting requires fewer surgeries, shorter hospitalization, with expected less expense.

Symptomatic communicating hydrocephalus in a contemporary cohort of high grade glioma patients.

INTRODUCTION: High grade glioma (HGG) treatment has seen a paradigm shift with intensified regimes, but hospitalisation burden is partially attributed to side effects of therapy. Symptomatic communicating hydrocephalus (HC) is a potential complication. Aim of this study was to investigate its incidence, risk factors and treatment in a contemporary cohort. METHODS: We performed a retrospective review of HGG patients. Patients with symptomatic communicating HC were identified and demographic, tumour and treatment variables extracted from hospital notes. Descriptive statistics were performed and odds ratios (OR) with 95% confidence intervals (CI) calculated. RESULTS: From a cohort of 278 eligible HGG patients, 8 (3%) were diagnosed with symptomatic communicating HC. In the subgroup of patients with intraoperative opening of the ventricular system during previous surgery (N = 66), hydrocephalus developed in 10.6% of cases (N = 7). Symptoms were lethargy (N = 5), headache (N = 3), confusion (N = 3), gait disturbance (N = 3) and urinary incontinence (N = 1); three patients presented resembling normal pressure hydrocephalus. A higher rate of intraoperative opening of the ventricles was found in the HC group (p = .0002); all other variables were equally distributed. The increased odds for developing HC for patients with intraoperative opening of the ventricles reached statistical significance (OR = 25.0339, 95% CI = 3.0196-207.5449, p = .0028), whereas previous radiotherapy only increased odds by tendency. Hydrocephalic patients were treated with ventriculoperitoneal shunts and all but one patient improved. One patient had a complication attributed to the shunt procedure The median overall survival after shunting was 4 months. CONCLUSIONS: Symptomatic communicating hydrocephalus occurred in 3% of HGG patients and in 10.6% in the subgroup with previous intraoperative opening of the ventricles. Treatment with a ventriculoperitoneal shunt is effective and has a low complication rate.

Ventriculitis Caused by Multidrug-Resistant Bacteria in a Medical Intensive Care Unit with Limited Resources.

The widespread use of various devices in the diagnosis or treatment of critically ill neurological patients has led to the more frequent appearance of a new group of meningitis and ventriculitis caused by resistant Gram-negative bacteria or staphylococci. In literature, it has been labeled as health care-associated meningitis and ventriculitis. In our clinical practice (in resource-limited countries), we still have any viable experience neither in the application of these diagnostic and therapeutic tools nor in the handling of complications resulting from their use. However, we have had positive results with the help of the existing guidelines and advice from colleagues in the region (through a video consultation model) while also respecting other factors that reflect our work environment.

Shunt age-related complications in adult patients with suspected shunt dysfunction. A recommended diagnostic workup.

BACKGROUND: Patients admitted for suspicion of shunt dysfunction (SD) often show unspecific symptoms and require time-consuming, expensive and even invasive diagnostics involving significant radiation exposure. The purpose of this retrospective study was to analyse the current diagnostic procedures and to propose a process optimisation. METHOD: As all patients admitted for suspicion of SD receive imaging studies, we searched for adult patients receiving neuroimaging in the period from January 2010 to July 2013, analysing referring diagnosis, clinical signs, products, diagnostic process and final diagnosis. Recursive partitioning was used to define time intervals for differentiating types of SD. RESULTS: A total of 148 patients, aged 18-89 (mean, 54) years, were studied. Forty-two percent were referred by a hospital or rehabilitation centre, 30% by general practitioners and 24% were self-referrals. The admission diagnosis was in the majority "shunt dysfunction" only. Further differentiations were rarely made. An SD was confirmed in 46% of the patients. In 17%, the symptoms were based on another cause and in 37% they could not be clearly attributed to any specific disorder. Abdominal dislocations (2%) and shunt infections (5%) were found within the first 6 months. Over- (3%) and under-drainage (14%) were the most frequent complications during the first 4 years. Disconnections (13%) occurred generally 4 years or more after implantation. Only shunt obstruction (9%) showed no temporal pattern. CONCLUSIONS: Symptoms of SD remain mostly unspecific. This study showed that the type of SD depends on the time interval from implantation. We propose a workup strategy for patients with SD based on the temporal profile.

Comparison of anti-siphon devices-how do they affect CSF dynamics in supine and upright posture?

BACKGROUND: Three different types of anti-siphon devices (ASDs) have been developed to counteract siphoning-induced overdrainage in upright posture. However, it is not known how the different ASDs affect CSF dynamics under the complex pressure environment seen in clinic due to postural changes. We investigated which ASDs can avoid overdrainage in upright posture best without leading to CSF accumulation. METHODS: Three shunts each of the types Codman Hakim with SiphonGuard (flow-regulated), Miethke miniNAV with proSA (gravitational), and Medtronic Delta (membrane controlled) were tested. The shunts were compared on a novel in vitro setup that actively emulates the physiology of a shunted patient. This testing method allows determining the CSF drainage rates, resulting CSF volume, and intracranial pressure in the supine, sitting, and standing posture. RESULTS: The flow-regulated ASDs avoided increased drainage by closing their primary flow path when drainage exceeded 1.39 ± 0.42 mL/min. However, with intraperitoneal pressure increased in standing posture, we observed reopening of the ASD in 3 out of 18 experiment repetitions. The adjustable gravitational ASDs allow independent opening pressures in horizontal and vertical orientation, but they did not provide constant drainage in upright posture (0.37 ± 0.03 mL/min and 0.26 ± 0.03 mL/min in sitting and standing posture, respectively). Consequently, adaptation to the individual patient is critical. The membrane-controlled ASDs stopped drainage in upright posture. This eliminates the risk of overdrainage, but leads to CSF accumulation up to the volume observed without shunting when the patient is upright. CONCLUSIONS: While all tested ASDs reduced overdrainage, their actual performance will depend on a patient's specific needs because of the large variation in the way the ASDs influence CSF dynamics: while the flow-regulated shunts provide continuous drainage in upright posture, the gravitational ASDs allow and require additional adaptation, and the membrane-controlled ASDs show robust siphon prevention by a total stop of drainage.

Routine cerebrospinal fluid analysis during 'de novo' ventriculoperitoneal shunt insertion: Single Institution Experience.

Background Cerebrospinal fluid (CSF) sampling is performed during ventriculoperitoneal (VP) shunting procedure surgery for early detection of infection. We have performed a retrospective study to determine whether routine intraoperative CSF sampling at new VP shunt insertion has predicted shunt infection or changed subsequent surveillance or management. Method From January 2011 to December 2013, 99 patients underwent first time VP shunt insertion at our hospital. The data collected from Beaumont Hospital Information System and operating theatre logbook. The reviewed data were patient demographics, the clinical condition requiring VP shunt procedure, shunt type, date of VP shunt insertion, date of VP shunt infection or malfunction and laboratory data. Results A first time VP shunt insertion procedure was performed in 99 patients. During the VP shunt insertion procedure, 64 patients had CSF sampling for microbiological analysis. The CSF culture was negative in all samples. All patients were followed up for 12 months. During the follow-up period, a total of 15 patients underwent VP shunt revision. Three of the shunt revisions were secondary to infection. The three infected shunt cases had sterile CSF cultures at the time of insertion. Conclusion There appears to be no correlation between CSF sampling during first time VP shunt insertion and the later development VP shunt infection. This questions the need for routine CSF sampling at the time of insertion. This would be confirmed as a part of future randomised trials.

Subdural haematoma complicating shunting for normal pressure hydrocephalus in the setting of concomitant antiplatelet medication - a report of 11 cases.

OBJECTIVE: To report on the occurrence and management of subdural haematoma after shunt implantation for normal pressure hydrocephalus and to determine the risk of recurrence in the setting of antiplatelet medication. METHODS: From a consecutive series of 80 patients implanted with a cerebrospinal fluid shunt for normal pressure hydrocephalus, records from 11 patients taking antiplatelet drugs, who subsequently had surgery for subdural haematoma were extracted and retrospectively reviewed. RESULTS: Patients were followed up for a mean of 1819 days after shunt implantation. Subdural haematomas occurred at a median of 335 days after shunt implantation - four ipsilateral, five contralateral and two bilateral with respect to the ventricular catheter. Three patients had reoperations done within a week without having resumed antiplatelet medication in the interim. One of them had three further reoperations done before the subdural collection disappeared. Only one patient had a late recurrence almost 11 years after shunt implantation. CONCLUSIONS: Subdural haematoma in the setting of a ventriculoperitoneal implantation for normal pressure hydrocephalus and concomitant antiplatelet medication can be managed along usual lines. Antiplatelet medication can be recommenced in due course with a low risk of recurrence.

Cross-sectional imaging of thoracic and abdominal complications of cerebrospinal fluid shunt catheters.

This study aims to review the imaging findings of distal (thoracic and abdominal) complications related to ventriculo-peritoneal (VP), ventriculo-pleural (VPL), and ventriculo-atrial (VA) cerebrospinal fluid (CSF) shunt catheter placement. Institution review board-approved single-center study of patients with thoracic and abdominal CSF catheter-related complications on cross-sectional imaging examinations over a 14-year period was performed. Clinical presentation, patient demographics, prior medical history, and subsequent surgical treatment were recorded. The presence or absence of CSF catheter-related infection and/or acute hydrocephalus on cross-sectional imaging was also recorded. There were 81 distal CSF catheter-related complications identified on 47 thoracic or abdominal imaging examinations in 30 patients (age 5-80 years, mean 39.3 years), most often on CT (CT = 42, MRI = 1, US = 4). Complications included 38 intraperitoneal and 11 extraperitoneal fluid collections. Extraperitoneal collections included nine abdominal wall subcutaneous (SC) pseudocysts associated with shunt migration and obesity, an intrapleural pseudocyst, and a breast pseudocyst. There were also two large VPL-related pleural effusions, a fractured catheter in the SC tissues, and a large VA shunt thrombus within the right atrium. Ten patients (33.3 %) had culture-positive infection from CSF or shunt catheter samples. Ten patients (33.3 %) had features of temporally related acute or worsening hydrocephalus on neuroimaging. In four of these patients, the detection of thoracic and abdominal complications on CT preceded and predicted the findings of acute hydrocephalus on cranial imaging. Thoracic and abdominal complications of CSF shunts, as can be identified on CT, include shunt infection and/or obstruction, may be both multiple and recurrent, and may be predictive of concurrent acute intracranial problems.