Surgical management of adult hydrocephalus

Minimally invasive third ventriculostomy with stereotactic internal shunt placement for the treatment of tumor-associated noncommunicating hydrocephalus

BACKGROUND

Intracranial tumors can cause obstructive hydrocephalus (OH). Most often, symptomatic treatment is pursued through ventriculoperitoneal shunt (VS) or endoscopic third ventriculostomy (ETV). In this study, we propose stereotactic third ventriculostomy with internal shunt placement (sTVIP) as an alternative treatment option and assess its safety and efficacy.

METHODS

In this single-center, retrospective analysis, clinical symptoms, procedure-related complications, and revision-free survival of all patients with OH due to tumor formations treated by sTVIP between January 2010 and December 2021 were evaluated.

RESULTS

Clinical records of thirty-eight patients (11 female, 27 male) with a mean age of 40 years (range 5-88) were analyzed. OH was predominantly (in 92% of patients) caused by primary brain tumors (with exception of 3 cases with metastases). Following sTVIP, 74.2% of patients experienced symptomatic improvement. Preoperative headache was a significant predictor of postoperative symptomatic improvement (OR 26.25; 95% CI 4.1-521.1; p = 0.0036). Asymptomatic hemorrhage was detected along the stereotactic trajectory in 2 cases (5.3%). One patient required local revision due to CSF fistula (2.6%); another patient had to undergo secondary surgery to connect the catheter to a valve/abdominal catheter due to CSF malabsorption. However, in the remaining 37 patients, shunt independence was maintained during a median follow-up period of 12 months (IQR 3-32 months). No surgery-related mortality was observed.

CONCLUSIONS

sTVIP led to a significant symptom control and was associated with low operative morbidity, along with a high rate of ventriculoperitoneal shunt independency during the follow-up period. Therefore, sTVIP constitutes a highly effective and minimally invasive treatment option for tumor-associated obstructive hydrocephalus, even in cases with a narrow prepontine interval.

Impacts of the COVID-19 Pandemic on the Healthcare Provision and Lived Experiences of Patients with Hydrocephalus

The emergence of COVID-19 (SARS-CoV-2) led to distancing measures which acutely affected healthcare infrastructure, leading to limited in-person clinical visits and an increased number of virtual appointments. This study aimed to examine the effects this had on adults with hydrocephalus by describing the lived experiences of a cohort of patients at an outpatient hydrocephalus clinic. Between early May and early July of 2020, remote structured interviews were conducted with participants. Interviews were in-depth and open-ended, allowing participants to reflect and expand on the effects of the social distancing mandate on their well-being and quality of care. Three themes emerged: (1) impacts of changes in treatment provision, (2) impacts of changes in mitigating activities, and (3) impacts of changes on personal well-being. The comprehensive understanding of lived experiences may inform the future provision of healthcare services and social policy. Improved approaches to remote care telemedicine have the potential to facilitate high-quality care.

The Sheep as a Comprehensive Animal Model to Investigate Interdependent Physiological Pressure Propagation and Multiparameter Influence on Cerebrospinal Fluid Dynamics

The present study aims to develop a suitable animal model for evaluating the physiological interactions between cerebrospinal fluid (CSF) dynamics, hemodynamics, and abdominal compartment pressures. We seek to contribute to the enhanced recognition of the pathophysiology of CSF-dependent neurological disorders like hydrocephalus and the improvement of available treatment options. To date, no comprehensive animal model of CSF dynamics exists, and establishing an accurate model will advance our understanding of complex CSF physiology. Persisting knowledge gaps surrounding the communication and pressure propagation between the cerebrospinal space and adjacent anatomical compartments exacerbate the development of novel therapies for neurological diseases. Hence, the need for further investigation of the interactions of vascular, craniospinal, and abdominal pressures remains beyond dispute. Moreover, the results of this animal study support the optimization of in vitro test benches for medical device development, e.g., ventriculoperitoneal shunts. Six female white alpine sheep were surgically equipped with pressure sensors to investigate the physiological values of intracranial, intrathecal, arterial, central venous, jugular venous, vesical pressure, and four differently located abdominal pressures. These values were measured simultaneously during the acute animal trial with sheep under general anesthesia. Both carotid and femoral arterial blood pressure indicate a reliable and comparable representation of the systematic blood pressure. However, the jugular venous pressure and the central venous pressure in sheep in dorsal recumbency do not correlate well under general anesthesia. Furthermore, there is a trend for possible comparability of lateral intraventricular and lumbar intrathecal pressure. Nevertheless, animal body position during measurements must be considered since different body constitutions can alter the horizontal line between the cerebral ventricles and the lumbar subarachnoid space. While intra-abdominal pressure measurement in the four different abdominal quadrants yielded greater inter-individual variability, intra-vesical pressure measurements in our setting delivered comparable values for all sheep. We established a novel and comprehensive ovine animal model to investigate interdependent physiologic pressure propagation and multiparameter influences on CSF dynamics. The results of this study will contribute to further in vitro bench testing, the derivation of novel quantitative models, and the development of a pathologic ovine hydrocephalus model.

Dynamic Occlusion of Distal Ventriculoperitoneal Shunt Catheter after Infusion Port Placement: A New Shunt Malfunction

Shunt failure requiring reintervention remains a common complication of hydrocephalus treatment. Here, we report a novel cause of mechanical shunt obstruction in an adult patient: position-dependent intermittent occlusion via an infusion port catheter. A 51-year-old woman with a grade II oligodendroglioma presented in a delayed fashion following surgery with a pseudomeningocele. She underwent ventriculoperitoneal shunt placement due to communicating hydrocephalus, resolving her pseudomeningocele. Shortly thereafter, she underwent placement of a subclavian infusion port at an outside institution. Her pseudomeningocele returned. Imaging demonstrated close proximity of her port catheter to the shunt catheter overlying the clavicle. Her shunt was tapped demonstrating a patent ventricular catheter with normal pressure. She underwent shunt exploration after her pseudomeningocele did not respond to valve adjustment. Intraoperative manometry demonstrated head position-dependent distal catheter obstruction. Repeat manometry following distal catheter revision demonstrated normal runoff independent of position. Her pseudomeningocele was resolved on follow-up. To our knowledge, this is the only reported case of intermittent, position-dependent distal catheter obstruction. Shunted patients with concern for malfunction following subclavian infusion port placement should be evaluated for possible dynamic obstruction of their distal catheter when the two catheters are in close proximity along the clavicle.

Acute cerebral venous outflow obstruction during convexity meningioma resection

BACKGROUND

Cerebral venous outflow obstruction involves idiopathic intracranial hypertension, and the most common related condition is dural venous sinus stenosis or, in other words, an obstruction of the dural venous sinuses. In these cases, the pathological process is often chronic, displays only mild symptoms, and rarely requires urgent surgical intervention. In this study, we present a unique case involving an acute cerebral venous outflow obstruction that occurred during meningioma resection that ultimately had catastrophic consequences.

MATERIALS AND METHODS

The patient's preoperative imaging only revealed an unremarkable frontal convexity meningioma with an average diameter exceeding 8 cm. She was admitted for a scheduled right frontoparietal craniotomy for lesion resection.

RESULTS

The patient's unique congenital dural venous sinus structure along with a non-surgical epidural hematoma both contributed to a catastrophic outcome, causing a progressive hemispheric encephalocele, significant blood loss, and wound closure difficulties.

CONCLUSION

Neurosurgeons should place an additional focus on cerebral venous outflow patency during tumor resection, even if the tumor does not involve the transverse or sigmoid sinuses. It is well known that the tacking sutures play an essential role in preventing an epidural hematoma, but the procedure to mitigate hematomas occurring outside the surgical field of view is not fully recognized by neurosurgeons. If dural tacking sutures are placed after complete tumor resection, the prophylactic effect for preventing EDH in the non-surgical areas may not be guaranteed. Therefore, we strongly advocate for the tacking sutures to be accurately placed before dural incisions are made.

Disappearance of a Distal Shunt Catheter: A Case Report of an Unusual Cause of Shunt Malfunction

Shunt malfunction is a common complication in patients who undergo ventriculoperitoneal shunt (VPS) placement for the treatment of hydrocephalus. A plethora of reports regarding shunt malfunctions due to distal catheter migration have been demonstrated in the literature. However, to our knowledge, there have been no reports thus far of shunt malfunctions caused by the complete disappearance of a distal catheter. A 70-year-old man was admitted to our hospital for progressive gait disturbance beginning approximately 5 months ago. He received a VPS for posthemorrhagic hydrocephalus and was doing well over the course of 18 months of follow-up. Since no increase in the size of the ventricle was observed on brain computed tomography taken at the outpatient clinic, we tried to readjust the pressure setting of his programmable shunt valve to relieve his symptoms. Without any progression, we discovered later by chance that the distal shunt catheter was missing. Shunt revision surgery was performed. At the 2-year follow-up, a slight improvement in gait was observed. Although it is very rare, the distal catheter can disappear without any noticeable symptoms. If shunt malfunction is suspected, it is important to check whether the entire shunt system is structurally intact.

Parinaud syndrome as an unusual presentation of intracranial hypotension

Background

Vertical gaze palsy is a rare clinical manifestation of intracranial hypotension. The typical features of intracranial hypotension include a postural headache, dural enhancement, and low cerebrospinal fluid (CSF) opening pressure.

Case Description

We describe a case of a shunt-dependent middle-aged female with aqueductal stenosis who developed recurrent presentations of upgaze palsy with postural headaches, confirmed low opening pressure, and slit ventricles on magnetic resonance imaging (MRI) due to shunt overdrainage. Her ophthalmoplegia and headaches improved following third ventriculostomy and with increasing the shunt opening pressure to prevent excess CSF drainage.

Conclusion

Intracranial hypotension should be considered part of the differential diagnosis for patients presenting with an upgaze palsy.

An Electrical Model of Hydrocephalus Shunt Incorporating the CSF Dynamics

The accumulation of cerebrospinal fluid (CSF) in brain ventricles and subarachnoid space is known as hydrocephalus. Hydrocephalus is a result of disturbances in the secretion or absorption process of CSF. A hydrocephalus shunt is an effective method for the treatment of hydrocephalus. In this paper, at first, the procedures of secretion, circulation, and absorption of CSF are studied and subsequently, the mathematical relations governing the pressures in different interacting compartments of the brain are considered. A mechanical-electrical model is suggested based on the brain physiology and blood circulation. In the proposed model, hydrocephalus is modeled with an incremental resistance (Ro) and hydrocephalus shunt, which is a low resistance path to drain the accumulated CSF in the brain ventricles, is modeled with a resistance in series with a diode. At the end, the simulation results are shown. The simulation results can be used to predict the shunt efficiency in reducing CSF pressure and before a real shunt implementation surgery is carried out in a patient's body.

Is endoscopic third ventriculostomy safe and efficient in the treatment of obstructive chronic hydrocephalus in adults? A prospective clinical and MRI study

BACKGROUND

In case of suspected normal pressure hydrocephalus, MRI is performed systematically and can sometimes highlight an obstruction of the flow pathways of the CSF (aqueductal stenosis or other downstream obstruction). It seems legitimate for these patients to ask the question of a treatment with endoscopic third ventriculostomy (ETV), even if the late decompensation of an obstruction may suggest an association with a CSF resorption disorder. The aim of this study was to evaluate clinical and radiological evolution after ETV in a group of elderly patients with an obstructive chronic hydrocephalus (OCH).

METHODS

ETV was performed in 15 patients with OCH between 2012 and 2017. Morphometric (callosal angle, ventricular surface, third ventricular width, and Evans' index) and velocimetric parameters (stroke volume of the aqueductal (SVa) CSF) parameters were measured prior and after surgery with brain MRI. The clinical score (mini-mental status examination (MMSE) and the modified Larsson's score, evaluating walking, autonomy, and incontinence) were performed pre- and postoperatively.

RESULTS

SVa was less than 15 μL/R-R in 12 out of the 15 patients; in the other three cases, the obstruction was located at a distance from the middle part of the aqueduct. Fourteen out of 15 patients were significantly improved: mean Larsson's score decreased from 3.8 to 0.6 (P ≤ 0.01) and mean MMSE increased from 25.7 to 28 (P = 0.084). Evans' index and ventricular area decreased postoperatively and the callosal angle increased (P ≤ 0.01). The mean follow-up lasted 17.9 months. No postoperative complications were observed.

CONCLUSION

ETV seems to be a safe and efficient alternative to shunt for chronic hydrocephalus with obstruction; the clinical improvement is usual and ventricular size decreases slightly.

Valve Failure in Ventriculoperitoneal Shunts of Neuro-Oncologic Patients: A Historical Cohort Study

OBJECTIVE

To investigate malfunctioning of ventriculoperitoneal shunt (VPS) valves in patients with brain tumors compared with patients with VPS for nontumoral etiologies to identify risk factors for shunt malfunction.

METHODS

Medical charts of all adult patients who underwent VPS surgery for hydrocephalus between 2011 and 2016 were reviewed. Incidence and risk factors for revision surgery due to valve malfunction were identified in patients with brain tumors (group A) and patients without brain tumors (group B).

RESULTS

Group A comprised 89 patients, and group B comprised 164 patients. The median follow-up time was 17 months for the entire cohort (9.4 months for group A vs. 25 months for group B, P < 0.001). VPS revision was performed in 60 patients (23.7%); 11 revisions involved valve failures necessitating valve replacement. Valve failures were significantly more common in group A (10 group A patients vs. 1 group B patient, P < 0.001). The distal or proximal shunt revision rate for reasons other than the valve was similar for both groups. Group A patients had a significantly higher cerebrospinal fluid protein level (44.5 mg/dL vs. 27.79 mg/dL, P < 0.05), and patients with valve failure had a 3-fold higher cerebrospinal fluid protein level compared with group A patients who experienced any type of shunt failure (96.3 mg/dL vs. 30.6 mg/dL, P < 0.05).

CONCLUSIONS

Shunt malfunction occurred mainly in patients with brain tumors and high cerebrospinal fluid protein levels. These patients are at high risk of valve failure and should be closely observed for emergent valve revision.

Neurosurgical complications: what the radiologist needs to know

Visits to the emergency department by patients who have recently undergone neurosurgery are a common occurrence, and these patients frequently receive emergent cross-sectional head imaging in order to evaluate for complications. Different neurosurgical approaches may have typical postoperative imaging findings that can be confused with pathology. Furthermore, particular abnormal postoperative imaging findings may signal an evolving complication. It is essential for the radiologist to understand common neurosurgical procedures and their potential complications in order to provide proper diagnostic evaluation of the postoperative neurosurgical patient. The purpose of this review is to assist radiologists in the evaluation of the postoperative neurosurgical patient and educate them on associated complications. Familiarity with common neurosurgical techniques and postoperative complications will help radiologists make the correct diagnosis, communicate effectively with the neurosurgeon, and expedite patient care.

Accuracy and safety of 1-day external lumbar drainage of CSF for shunt selection in patients with idiopathic normal pressure hydrocephalus

OBJECTIVE

Three to five days of external lumbar drainage (ELD) of CSF is a test for ventriculoperitoneal shunt (VPS) selection in idiopathic normal pressure hydrocephalus (iNPH). The accuracy and complication rates of a shorter (1-day) ELD procedure were analyzed.

METHODS

Data of patients with iNPH who underwent 1-day ELD to be selected to undergo VPS placement with a programmable valve in the period from 2005 to 2015 were reviewed. Patients experiencing VPS complications, valve malfunctioning, or with less than 1 year of follow-up were excluded. The ability of 1-day ELD to predict VPS outcome at 1- and 12-month follow-up was assessed by calculating sensitivity, specificity, and positive and negative predictive values.

RESULTS

Of 93 patients who underwent 1-day ELD, 3 did not complete the procedure. Of the remaining 90 patients, 2 experienced transient nerve root irritation. Twenty-four patients had negative test outcomes and 66 had positive test outcomes. Nine negative-outcome patients had intraprocedural headache, which showed 37.5% sensitivity (95% confidence interval [CI] 19.5%-59.2%) and 100% specificity (95% CI 93.1%-100%) as predictors of negative 1-day ELD outcome. Sixty-eight patients (6 with negative and 62 with positive outcomes) underwent VPS insertion, which was successful in 0 and 58 patients, respectively, at 1-month follow-up. Test sensitivity and specificity in predicting surgical outcome at 1-month follow-up were 100% (95% CI 92.3%-100%) and 60% (95% CI 27.4%-86.3%), respectively, with 94.1% accuracy (95% CI 85.6-98.4%). Among the 1-day ELD-positive patients, 2 showed no clinical benefit at 12 months follow-up. Test sensitivity and specificity in predicting surgical outcome at 12-month follow-up was 100% (95% CI 92.5%-100%) and 75.0% (95% CI 35.6%-95.5%), respectively, with 97.1% (95% CI 89.8%-99.6%) accuracy.

CONCLUSIONS

One-day ELD is a reliable tool in iNPH management, with low complication risk and short trial duration. The test is very consistent in predicting who will have a positive outcome with VPS placement, given the high chance of successful outcome at 1- and 12-month follow-up; negative-outcome patients have a high risk of unsuccessful surgery. Intraprocedural headache is prognostic of 1-day ELD negative outcome.

One-year outcome of patients with posttraumatic hydrocephalus treated by lumboperitoneal shunt: an observational study from China

BACKGROUND

Lumboperitoneal shunt (LPS) attracts increasing number of research interest in the treatment of hydrocephalus due to minimal invasiveness. However, the outcome of LPS-treated posttraumatic hydrocephalus (PTH) is poorly learnt, remaining unknown to date.

METHODS

We retrospectively analyzed adult patients with PTH treated by LPS in our department between May 2013 and Apr 2017. Baseline characteristics, preoperative clinical features, symptomatic and imageologic improvement, and postoperative complications were synchronously investigated. All patients were followed up to 1 year after LPS to determine the shunt outcome and quality of life. Furthermore, the Kaplan-Meier curve was drawn and binary logistic regression analysis was used to identify the possible predictive factors of shunt failure.

RESULTS

Thirty-eight eligible patients were included in our study. Five days after LPS, chronic hydrocephalus scores (CHS; 10.26 ± 5.17 vs 5.21 ± 3.75; P < 0.001) and Evans index (0.36 ± 0.06 vs 0.28 ± 0.06; P < 0.001) were significantly improved with statistical difference. The overall incidence of complications was 50% (19 patients) while hydrocephalus-associated death or shunt failure was not observed immediately after LPS. According to the 1-year follow-up, most of the patients obtained good prognosis while 16 patients (42.1%) were failed, including 15 patients (39.5%) underwent shunt revision and one patient (2.6%) was dead ascribing to shunt malfunction. However, we failed to screen out any factors contributing to LPS failure.

CONCLUSION

To sum up, we have, for the first time, demonstrated that LPS could be a potential option to treat PTH.

Computerized gait analysis with inertial sensor in the management of idiopathic normal pressure hydrocephalus

BACKGROUND

Gait disturbance (GD) is usually the first and most prominent symptom observed in idiopathic normal pressure hydrocephalus (iNPH). The reversibility of symptoms is related to early diagnosis and treatment. Nowadays early recognition of patients is challenging because GD in the elderly is frequently neglected, leading to late diagnosis and increased disability. In addition, GD is generally assessed by clinical evaluation since computerized gait analysis methods are rarely available. In the present study, we demonstrate the clinical application of an inertial sensor system for gait analysis in iNPH.

AIM

The primary aim was to test the sensor performance in quantifying impairment in gait parameters in iNPH. The secondary aim was to detect a range of improvement after CSF subtraction test, which could be considered as predictive of favorable shunt response.

DESIGN

We performed a case-control prospective study from March 2012 to May 2014.

SETTING

Inpatients at the Division of Neurology, Department of Clinical and Experimental Sciences, Brescia.

POPULATION

We enrolled 79 patients with clinical and radiological findings of iNPH and 300 healthy adults over 70 years old without GD as a control group.

METHODS

We performed gait analysis, CSF Tap Test (TT), and shunt surgery in all patients with a diagnosis of iNPH according to the International Guidelines. According to clinical outcomes, we divided patients in responsive (group A) and non-responsive (group B). We then compared pre-operative gait analysis of group A with the control group, and calculated the percentage of improvement after TT between group A and group B.

RESULTS

Shunt surgery was performed in 52 patients. After 3 months, 35 patients (group A: 67.3%) showed a positive response to shunt. We quantified the impaired gait parameters in iNPH and assessed the differences with controls. Improvement of speed, stride length and double support time after TT was predictive of positive shunt response.

CONCLUSIONS

The proposed inertial sensor system is a reliable and easy-to-use system for early detection of iNPH and may be used in any clinical setting.

CLINICAL REHABILITATION IMPACT

Identification of a GD pattern for iNPH, especially in rehabilitation, may be useful for recognizing patients who are candidates for surgery, thus avoiding permanent disability.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Comparative durability and costs analysis of ventricular shunts

OBJECTIVEVentricular shunt (VS) durability has been well studied in the pediatric population and in patients with normal pressure hydrocephalus; however, further evaluation in a more heterogeneous adult population is needed. This study aims to evaluate the effect of diagnosis and valve type-fixed versus programmable-on shunt durability and cost for placement of shunts in adult patients.METHODSThe authors retrospectively reviewed the medical records of all patients who underwent implantation of a VS for hydrocephalus at their institution over a 3-year period between August 2013 and October 2016 with a minimum postoperative follow-up of 6 months. The primary outcome was shunt revision, which was defined as reoperation for any indication after the initial procedure. Supply costs, shunt durability, and hydrocephalus etiologies were compared between fixed and programmable valves.RESULTSA total of 417 patients underwent shunt placement during the index time frame, consisting of 62 fixed shunts (15%) and 355 programmable shunts (85%). The mean follow-up was 30 ± 12 (SD) months. The shunt revision rate was 22% for programmable pressure valves and 21% for fixed pressure valves (HR 1.1 [95% CI 0.6-1.8]). Shunt complications, such as valve failure, infection, and overdrainage, occurred with similar frequency across valve types. Kaplan-Meier survival curve analysis showed no difference in durability between fixed (mean 39 months) and programmable (mean 40 months) shunts (p = 0.980, log-rank test). The median shunt supply cost per index case and accounting for subsequent revisions was $3438 (interquartile range $2938-$3876) and $1504 (interquartile range $753-$1584) for programmable and fixed shunts, respectively (p < 0.001, Wilcoxon rank-sum test). Of all hydrocephalus etiologies, pseudotumor cerebri (HR 1.9 [95% CI 1.2-3.1]) and previous shunt malfunction (HR 1.8 [95% CI 1.2-2.7]) were found to significantly increase the risk of shunt revision. Within each diagnosis, there were no significant differences in revision rates between shunts with a fixed valve and shunts with a programmable valve.CONCLUSIONSLong-term shunt revision rates are similar for fixed and programmable shunt pressure valves in adult patients. Hydrocephalus etiology may play a significant role in predicting shunt revision, although programmable valves incur higher supply costs regardless of initial diagnosis. Utilization of fixed pressure valves versus programmable pressure valves may reduce supply costs while maintaining similar revision rates. Given the importance of developing cost-effective management protocols, this study highlights the critical need for large-scale prospective observational studies and randomized clinical trials of ventricular shunt valve revisions and additional patient-centered outcomes.

A counterforce to diversion of cerebrospinal fluid during ventriculoperitoneal shunting: the intraperitoneal pressure. An observational study

BACKGROUND

Intraperitoneal pressure (IPP) counteracts the diversion of cerebrospinal fluid (CSF) from the cranial to the peritoneal compartment during ventriculoperitoneal shunting. Animal studies suggest that the intrinsic IPP exceeds the intraperitoneal hydrostatic pressure. The intrinsic IPP in mobile patients is relevant for shunt therapy, but data about it is not available.

METHODS

The IPP was measured indirectly in 25 mobile subjects (13 female) by applying a standard intravesical pressure measurement technique. Measurements were carried out in reference to the navel (supine position) and the xiphoid (upright position). Results were adjusted for the intraperitoneal hydrostatic pressure and correlated afterward with general body measures.

RESULTS

The corrected mean (SD) IPP measured in the supine position was 4.4 (4.5) cm H₂O, and the mean (SD) upright IPP was 1.6 (7.8) cm H₂O (p = 0.02). A positive correlation was found between the body mass index (BMI) and the IPP in the upright (r = 0.51) and supine (r = 0.65) body positions, and between the abdominal circumference and the IPP in the supine position (r = 0.63).

CONCLUSIONS

The intrinsic IPP in mobile subjects exceeds the intraperitoneal hydrostatic pressure. Thus, the intrinsic IPP counteracts the diversion of CSF into the peritoneal compartment. The intrinsic IPP is correlated with mobile patients' general body measures.

Ventriculomegaly in the Elderly: Who Needs a Shunt? A MRI Study on 90 Patients

OBJECTIVE

In the case of ventriculomegaly in the elderly, it is often difficult to differentiate between communicating chronic hydrocephalus (CCH) and brain atrophy. The aim of this study is to describe the MRI criteria of CCH, defined by a symptomatic patient with ventriculomegaly and that improved after shunt placement.

MATERIALS AND METHODS

Magnetic resonance imaging was prospectively evaluated in 90 patients with ventriculomegaly. Patients were classified into three groups: patients without clinical signs of CCH (control, n = 47), patients with CCH treated by shunt placement with clinical improvement (responders, n = 36), and patients with CCH treated using a shunt without clinical improvement (nonresponders, n = 7). MRI parameters of the two groups of interest (responders vs. controls) were compared.

RESULTS

Compared with controls, Evans' index (p = 0.029), ventricular area (p < 0.01), and volume (p = 0.0001) were higher in the responders. In this group, the callosal angle was smaller (p ≤ 0.0001) and the aqueductal stroke volume (SVa) of CSF was higher (p ≤ 0.0001) than in controls. On the ROC curves, the optimal cut-off values for differentiating between responders and controls were a ventricular area >33.5 cm², a callosal angle <90.8° and a SVa > 136.5 μL/R-R. In multivariate analysis, responders remained associated with SVa and callosal angle, with a c-statistic of 0.90 (95%CI, 0.83-0.98).

CONCLUSION

On suspicion of CCH, a large ventricular area, a small callosal angle, and an increased aqueductal stroke volume are important MRI arguments that can be associated with the clinical evaluation and dynamic testing of CSF to confirm the indication for a shunt.

Efficacy and safety of programmable shunt valves for hydrocephalus: A meta-analysis

OBJECTIVES

Shunt implantation is an option in the treatment of hydrocephalus. However, the benefits and adverse effects of programmable shunt valves have not been well assessed.

MATERIALS AND METHODS

Randomized controlled trials (RCTs) and observational studies assessing the efficacy and safety of programmable valves (PV) treatment for hydrocephalus were identified from electronic databases (PubMed, EMBASE, and Cochrane library). The meta-analysis was performed with the fixed-effect model or random-effect model according to heterogeneity.

RESULTS

Three RCTs and eight observational studies met the inclusion criteria including 2622 subjects. Compared with non-PV, PV treatment did not have a statistically significant effect on one-year shunt survival rate [relative risk (RR), 1.06; 95% confidence interval (CI), 0.84-1.35], Substantial heterogeneity was observed between studies (P = 0.09; I² = 65%). PV administration significantly reduced revision rate (RR, 0.56; 95% CI, 0.45-0.69; I² = 29%; P = 0.23) and over- or under-drainage complications rate (RR, 0.55; 95% CI, 0.32-0.96). PV was not associated with increased rates of other adverse events, including overall complications rate, infection rate and catheter-related complications rate.

CONCLUSIONS

PV treatment is safe and may reduce the revision rate and over- or under-drainage complication rate, especially in patients aged less than 18 years with hydrocephalus. PV treatment is not associated with decreased overall complication rates in patients with hydrocephalus, but the trial sequential analysis indicate more studies are needed to confirm this result.

Epidemiology of adult-onset hydrocephalus: institutional experience with 2001 patients

OBJECTIVE Adult-onset hydrocephalus is not commonly discussed in the literature, especially regarding its demographic distribution. In contrast to pediatric hydrocephalus, which is related to a primary CSF pathway defect, its development in adults is often secondary to other pathologies. In this study, the authors investigated the epidemiology of adult-onset hydrocephalus as it pertains to different etiologies and in reference to age, sex, and race distributions. METHODS The authors retrospectively reviewed the clinical notes of 2001 patients with adult-onset hydrocephalus who presented to Louisiana State University Health Sciences Center within a 25-year span. Significant differences between the groups were analyzed by a chi-square test; p < 0.05 was considered significant. RESULTS The overall mean (± SEM) incidence of adult hydrocephalus in this population was 77 ± 30 per year, with a significant increase in incidence in the past decade (55 ± 3 [1990-2003] vs 102 ± 6 [2004-2015]; p < 0.0001). Hydrocephalus in a majority of the patients had a vascular etiology (45.5%) or was a result of a tumor (30.2%). The incidence of hydrocephalus in different age groups varied according to various pathologies. The incidence was significantly higher in males with normal-pressure hydrocephalus (p = 0.03) or head injury (p = 0.01) and higher in females with pseudotumor cerebri (p < 0.0001). In addition, the overall incidence of hydrocephalus was significantly higher in Caucasian patients (p = 0.0002) than in those of any other race. CONCLUSIONS Knowledge of the demographic variations in adult-onset hydrocephalus is helpful in achieving better risk stratification and better managing the disease in patients. For general applicability, these results should be validated in a large-scale meta-analysis based on a national population database.

Endoscopic Third Ventriculostomy in Normal Pressure Hydrocephalus and Symptomatic Long-standing Overt Ventriculomegaly

Objectives:

The aim of this study is to define the role and effectiveness for an endoscopic third ventriculostomy (ETV) in patients with seconder normal pressure hydrocephalus(SNPH), idiopathic normal pressure hydrocephalus (INPH) and symptomatic longstanding overt ventriculomegaly (SLOVA).

Materials and Methods:

3 patients with SLOVA, 3 patients with INPH and 3 patients with SNPH underwent ETV were studied retrospectively. The patients had a follow-up of 1-6 years. Preoperative CT or/and MRI of the brain was done in all cases. Tap test was done in all cases. Clinical examination finding were classified according to the by Japanese Committee for Scientific Research (JCSS) on intractable Hydrocephalus. Patients were studied to evaluate of the patency of ventriculosthomy and aqueduclus slyvius by a Cine PC MR and CSF_DRİVE T2 Sequence MRI after 1-6 years.

Results:

Headache, gait disturbance and pollakiuria improved in three patients with SNPH underwent ETV, but dementia didn’t improve in one patient. Pollakiuria and headache improved in three patients with INPH underwent ETV but preoperative gait disturbance grade three remained unchanged in one patient. Headache improved in three patients with SLOVA underwent ETV. Preoperative gait disturbance grade 3 remained unchanged in one patient, but improved pollakiuria. We confirmed the patency of a third ventriculostomy and decreasing degrees of CSF flow into the aquaductus sylvius.

Conclusions:

In properly selected patients with SNPH, SLOVA and INPH who had headache, slight gait disturbance and pollakiuria, mainly those with a short duration of symptoms, ETV may provide good results.

Female gender predisposes for cerebrospinal fluid overdrainage in ventriculoperitoneal shunting

BACKGROUND

Gravitational valves (GVs) prevent overdrainage in ventriculoperitoneal shunting (VPS). However, there are no data available on the appropriate opening pressure in the shunt system when implementing a GV. We performed a retrospective analysis of hydrocephalic patients who were successfully treated with VPS which included one or more GV.

METHOD

In this retrospective study in adult VPS patients with GVs, we analysed all available data, including the most recent computed tomography (CT) scans, to determine the best adjustments for alleviating any symptoms of overdrainage and underdrainage. Vertical effective opening pressure (VEOP) of the entire shunt system, including the differential pressure valve, was determined.

RESULTS

One hundred and twenty-two patients were eligible for the study. Of these, female patients revealed a higher VEOP compared with males (mean, 35.6 cmH2O [SD ± 2.46] vs 28.9 cmH2O [SD ± 0.87], respectively, p = 0.0072, t-test). In patients older than 60 years, lower VEOPs, by a mean of 6.76 cmH2O ± 2.37 (p = 0.0051), were necessary. Mean VEOP was found to be high in idiopathic intracranial hypertension (IIH; 41.6 cmH2O) and malresorptive and congenital HC (35.9 and 36.3), but low in normal pressure HC (27.5, p = 0.0229; one-way ANOVA). In the total cohort, body mass index (BMI) and height did not correlate with VEOP. Twelve patients required a VEOP of more than 40 cmH2O, and in eight of these patients this was accomplished by using multiple GVs. All but one of these eight patients were of female gender, and none of the latter were treated for normal pressure hydrocephalus (NPH) (p = 0.0044 and p = 0.0032, Fisher's exact test).

CONCLUSIONS

In adult VPS patients, female gender increases the risk of overdrainage requiring higher VEOPs. Initial implantation of adjustable GV should be considered in female patients treated with VP shunts for pathology other than NPH.

Evaluation of Ventriculoperitoneal Shunt-Related Complications in Intracranial Meningioma with Hydrocephalus

Objective Meningioma is a common intracranial tumor that predisposes patients to hydrocephalus which may require a permanent cerebrospinal fluid (CSF) diversion procedure such as ventriculoperitoneal (VP) shunts. We reviewed our long-term experience with VP shunts for the management of hydrocephalus in patients with meningioma. Methods and Materials A total of 48 Patients with meningioma who underwent VP shunt insertion for hydrocephalus from 1990 to 2013 was included in our case series. The study population was evaluated clinically and radiographically after VP shunt placement. Results Overall shunt failure was seen in 13 (27%) patients. Single and multiple shunt revisions were required in eight (16.7%) and five (10.4%) patients, respectively. The overall shunt revision within 6 months, 1 , and 5 years was 19, 23, and 27%, respectively. Male patient was significantly associated with the longer survival after shunt placement. Revisions free survival after 3, 5, 10, and 15 years of VP shunt placement were 70, 46, 30, and 20%, respectively. Finally, in regression analysis, age greater than 65 years (p = 0.02, 95% confidence interval (CI) = 0.1-0.13), tumor in posterior fossa (p < 0.0001, 95% CI = 0.1-0.23), tumor size (> 5 cm) (p = 0.3, 95% CI = 0.01-0.19), and Simpson resection grades II to IV (p = 0.04, 95% CI = 0.07-0.2) were identified as positive predictors of requirement of CSF flow diversion Conclusion The findings of the present study reveal that VP shunting is an important treatment option for the management of hydrocephalus in patients with meningioma. Further studies using less invasive techniques are warranted to compare the benefits of VP shunt for the management of hydrocephalus.

Antibiotic prophylaxis for shunt surgery of children: a systematic review

OBJECTIVE

The object of this study was to evaluate the clinical effectiveness of antibiotic prophylaxis in children who underwent placement of intracranial ventricular shunts.

METHODS

In this paper, the authors report a systematic review and meta-analysis of infection rate for pediatric shunt implantation surgery. Randomized or non-randomized controlled trials for comparing the use of prophylactic antibiotics in intracranial ventricular shunt procedures with placebo or no antibiotics were included in the review.

RESULTS

Seven published reports of eligible studies involving 694 participants meet the inclusion criteria. Compared with the control group, antibiotic prophylaxis had made a significant difference in infection rate (RR = 0.59, 95% CI = 0.38, 0.90, P < 0.05).

CONCLUSION

Although current evidence demonstrates that antibiotic prophylaxis can lead to a significant reduction of the infection rate of shunt surgery, more evidence from advanced multi-center studies is needed to provide instruction for the use of prophylactic antibiotics.

Intracranial pressure for the characterization of different types of hydrocephalus: A Permutation Entropy study

Hydrocephalus is a condition characterized by altered cerebrospinal fluid (CSF) dynamics and chronic rises in intracranial pressure (ICP). However, the reason why hydrocephalic physiologies fail to inhibit dangerously high ICP levels is not known. Infusion studies are used to raise ICP and evaluate CSF circulation disorders. In this pilot study, ICP signals recorded during infusion tests from 33 patients with normal pressure hydrocephalus and 36 patients having developed a secondary form of normal pressure hydrocephalus were characterized using Permutation Entropy (PE), a symbolic non-linear method to quantify complexity. Each ICP signal was divided into four epochs--baseline (before infusion begins), infusion, plateau, and recovery (after infusion has stopped)--and the mean PE was calculated for each epoch. Statistically significant differences were found between PE for most epochs (p<;0.00833, Bonferroni-corrected Wilcoxon tests), with a significant decrease in the plateau phase. However, differences between PE for normal pressure and secondary hydrocephalus were not significant. Results suggest that the increase in ICP during infusion studies is associated with a significant decrease in PE. PE analysis of ICP signals could be useful for increasing our understanding of CSF dynamics in normal pressure hydrocephalus.

Obstructive hydrocephalus as a result of giant cell tumor of the thoracic spine: A case report

Giant cell tumors (GCTs) are rare bone tumors that account for ~5% of all primary bone tumors. When GCTs occur in the spine, patients usually present with localized pain and neurological symptoms, such as radiating pain or hyperesthesia. In the current report, an unusual case of a GCT of the thoracic spine associated with hydrocephalus is described. A 48-year-old male presented with urinary retention, loss of sensation in the lower limbs and inability to walk. The patient eventually developed hydrocephalus combined with altered consciousness, indicated by an inability to follow simple commands. Magnetic resonance (MR) imaging demonstrated the presence of a soft tissue mass at the T2 level, and biopsy examination of the tissue confirmed that it was a GCT. The patient experienced a sudden loss of consciousness due to an acute episode of obstructive hydrocephalus. A ventriculoperitoneal shunting procedure was performed to treat the hydrocephalus, and the patient regained normal consciousness, although the paraplegia persisted. An MR examination performed 30 months following surgery demonstrated that the tumor size was stable, consistent with the slow growth that is characteristic of GCTs. Diagnosis of GCTs may be challenging, and relies on radiographic and histopathologic findings. Although rare, acute hydrocephalus as a result of GCTs should not be excluded from a differential diagnosis.

Comparison of Intracranial Neuroendoscopic Procedures in Children versus Adults

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

In vitro performance and principles of anti-siphoning devices

BACKGROUND

Anti-siphon devices (ASDs) of various working principles were developed to overcome overdrainage-related complications associated with ventriculoperitoneal shunting.

OBJECTIVE

We aimed to provide comparative data on the pressure and flow characteristics of six different types of ASDs (gravity-assisted, membrane-controlled, and flow-regulated) in order to achieve a better understanding of these devices and their potential clinical application.

METHODS

We analyzed three gravity-dependent ASDs (ShuntAssistant [SA], Miethke; Gravity Compensating Accessory [GCA], Integra; SiphonX [SX], Sophysa), two membrane-controlled ASDs (Anti-Siphon Device [IASD], Integra; Delta Chamber [DC], Medtronic), and one flow-regulated ASD (SiphonGuard [SG], Codman). Defined pressure conditions within a simulated shunt system were generated (differential pressure 10-80 cmH2O), and the specific flow and pressure characteristics were measured. In addition, the gravity-dependent ASDs were measured in defined spatial positions (0-90°).

RESULTS

The flow characteristics of the three gravity-assisted ASDs were largely dependent upon differential pressure and on their spatial position. All three devices were able to reduce the siphoning effect, but each to a different extent (flow at inflow pressure: 10 cmH2O, siphoning -20 cmH2O at 0°/90°: SA, 7.1 ± 1.2*/2.3 ±  0.5* ml/min; GCA, 10.5 ± 0.8/3.4 ± 0.4* ml/min; SX, 9.5 ± 1.2*/4.7 ± 1.9* ml/min, compared to control, 11.1 ± 0.4 ml/min [*p < 0.05]). The flow characteristics of the remaining ASDs were primarily dependent upon the inflow pressure effect (flow at 10 cmH2O, siphoning 0 cmH2O/ siphoning -20cmH2O: DC, 2.6 ± 0.1/ 4 ± 0.3* ml/min; IASD, 2.5 ± 0.2/ 0.8 ± 0.4* ml/min; SG, 0.8 ± 0.2*/ 0.2 ± 0.1* ml/min [*p < 0.05 vs. control, respectively]).

CONCLUSION

The tested ASDs were able to control the siphoning effect within a simulated shunt system to differing degrees. Future comparative trials are needed to determine the type of device that is superior for clinical application.

Feasibility of telemetric ICP-guided valve adjustments for complex shunt therapy

OBJECT

The advances in shunt valve technology towards modern adjustable differential pressure (DP) valves and adjustable gravitational assisted valves result in an increasing complexity of therapeutical options. Modern telemetric intracranial pressure (ICP) sensors may be helpful in their application for diagnostic purposes in shunt therapy. We present our first experiences on telemetric ICP-guided valve adjustments in cases with the combination of an adjustable DP valve and adjustable gravitational unit.

METHODS

Four consecutive cases were evaluated in a retrospective review who had received a proGAV adjustable, gravitational assisted DP valve with secondary in-line implantation of an adjustable shunt assistant (proSA), together with a telemetric ICP sensor (Neurovent-P-tel) between December 2010 and June 2012 in our institution. The measured ICP values and the corresponding valve adjustments were analyzed in correlation with the clinical course and the cranial imaging of the patients.

RESULTS

No surgery-related complications were observed after implantation of the proSA and the telemetric ICP sensor additional to the proGAV. ICP values could actively be influenced by adjustments of the respective valve units. An increase of the position depending resistance of the proSA resulted in significant attenuated negative ICP values for the standing position, while adjustments of the proGAV could be detected not only in a supine position but also in a standing position. A clinical improvement could be achieved in all cases.

CONCLUSION

The combination of adjustability in the differential pressure valve and the gravitational unit reveals a complex combination which may be difficult to adapt only according to clinical information. Telemetric ICP-guided valve adjustments seem to be a promising tool as an objective measure according to different body positions. Further investigations are needed to select the patients for these costly implants.

Differential pressure in shunt therapy: investigation of position-dependent intraperitoneal pressure in a porcine model

OBJECT

The differential pressure between the intracranial and intraperitoneal cavities is essential for ventriculoperitoneal shunting. A determination of the pressure in both cavities is decisive for selecting the appropriate valve type and opening pressure. The intraperitoneal pressure (IPP)-in contrast to the intracranial pressure-still remains controversial with regard to its normal level and position dependency.

METHODS

The authors used 6 female pigs for the experiments. Two transdermal telemetric pressure sensors (cranial and caudal) were implanted intraperitoneally with a craniocaudal distance of 30 cm. Direct IPP measurements were supplemented with noninvasive IPP measurements (intragastral and intravesical). The IPP was measured with the pigs in the supine (0°), 30°, 60°, and vertical (90°) body positions. After the pigs were euthanized, CT was used to determine the intraperitoneal probe position.

RESULTS

With pigs in the supine position, the mean (± SD) IPP was 10.0 ± 3.5 cm H2O in a mean vertical distance of 4.5 ± 2.8 cm to the highest level of the peritoneum. The difference between the mean IPP of the cranially and the caudally implanted probes (Δ IPP) increased according to position, from 5.5 cm H2O in the 0° position to 11.5 cm H2O in the 30° position, 18.3 cm H2O in the 60° position, and 25.6 cm H2O in the vertical body position. The vertical distance between the probe tips (cranially implanted over caudally implanted) increased 3.4, 11.2, 19.3, and 22.3 cm for each of the 4 body positions, respectively. The mean difference between the Δ IPP and the vertical distance between both probe tips over all body positions was 1.7 cm H2O.

CONCLUSIONS

The IPP is subject to the position-dependent hydrostatic force. Normal IPP is able to reduce the differential pressure in patients with ventriculoperitoneal shunts.

Programmable shunt valves for the treatment of hydrocephalus: a systematic review

OBJECTIVE

To evaluate the clinical effectiveness of programmable valves compared with non-programmable valves of hydrocephalus.

METHODS

In this paper, the authors report a systematic review and meta-analysis of complications and revision rate for programmable valves and non-programmable implantation. Randomized or non-randomized controlled trials of hydrocephalus treated by programmable and non-programmable valves were considered for inclusion.

RESULTS

Seven published reports of eligible studies involving 1702 participants meet the inclusion criteria. Compared with non-programmable, programmable valves had no significant difference in catheter-related complications [RR = 0.88, 95%CI (0.66,1.19), p = 0.10] and infection rate [RR = 1.25, 95%CI (0.92,1.69), p = 1.00]. There were significant differences in overall complications [RR = 0.80, 95%CI (0.67,0.96), p < 0.01], over-drainage or under-drainage complications [RR = 0.44, 95%CI (0.31,0.63), p < 0.01] and revision rate [RR = 0.56, 95%CI (0.45,0.69), p < 0.01] in favor of programmable valves.

CONCLUSION

Although the studies seem to demonstrate a small advantage for the programmable shunts, the probable bias and the difficulties in patient selection are too important to make a general conclusion.

Spectral analysis of intracranial pressure signals recorded during infusion studies in patients with hydrocephalus

Hydrocephalus includes a number of disorders characterised by clinical symptoms, enlarged ventricles (observable using neuroimaging techniques) and altered cerebrospinal fluid (CSF) dynamics. Infusion tests are one of the available procedures to study CSF circulation in patients with clinical and radiological features of hydrocephalus. In them, intracranial pressure (ICP) is deliberately raised and CSF circulation disorders evaluated through measurements of the resulting ICP. In this study, we analysed seventy-seven ICP signals recorded during infusion tests using four spectral-based parameters: median frequency (MF) and relative power (RP) in three frequency bands. These measures provide a novel perspective for the analysis of ICP signals in the frequency domain. Each signal was divided into four artefact-free epochs (corresponding to the basal, early infusion, plateau and recovery phases of the infusion study). The four spectral parameters were calculated for each epoch. We analysed differences between epochs of the infusion test and correlations between these epochs and patient data. Statistically significant differences (p < 1.7 × 10(-3), Bonferroni-corrected Wilcoxon signed-rank tests) were found between epochs of the infusion test using MF and RP. Furthermore, some spectral parameters (MF in the basal phase, RP for the first frequency band and in the early infusion phase, RP for the second frequency band and in all phases of the infusion study and RP in the third frequency band and in the basal phase) revealed significant correlations (p < 0.01) between epochs of the infusion test and signal amplitude in the basal and plateau phases. Our results suggest that spectral analysis of ICP signals could be useful for understanding CSF dynamics in hydrocephalus.

Shunting with gravitational valves—can adjustments end the era of revisions for overdrainage-related events?

Object

Overdrainage of CSF remains an unsolved problem in shunt therapy. The aim of the present study was to evaluate treatment options on overdrainage-related events enabled by the new generation of adjustable gravity-assisted valves.

Methods

The authors retrospectively studied the clinical course of 250 consecutive adult patients with various etiologies of hydrocephalus after shunt insertion for different signs and symptoms of overdrainage. Primary and secondary overdrainage were differentiated. The authors correlated the incidence of overdrainage with etiology of hydrocephalus, opening valve pressure, and patient parameters such as weight and size. Depending on the severity of overdrainage, they elevated the opening pressure, and follow-up was performed until overdrainage was resolved.

Results

The authors found 39 cases (15.6%) involving overdrainage-related problems—23 primary and 16 secondary overdrainage. The median follow-up period in these 39 patients was 2.1 years. There was no correlation between the incidence of overdrainage and any of the following factors: sex, age, size, or weight of the patients. There was also no statistical significance among the different etiologies of hydrocephalus, with the exception of congenital hydrocephalus. All of the “complications” could be resolved by readjusting the opening pressure of the valve in one or multiple steps, avoiding further operations.

Conclusions

Modern adjustable and gravity-assisted valves enable surgeons to set the opening pressure relatively low to avoid underdrainage without significantly raising the incidence of overdrainage and to treat overdrainage-related clinical and radiological complications without surgical intervention.

Steady-state indicators of the intracranial pressure dynamic system using geodesic distance of the ICP pulse waveform

Normal functioning of the brain depends on the homeostasis (∼ steady state) of its various physiological sub-systems, one of which is the intracranial pressure (ICP) dynamic system. The ICP dynamic system of an injured brain is susceptible to various acute changes that should ideally be detected by ICP monitoring even for comatose patients. However, the status quo of ICP monitoring solely targets mean ICP. We aimed to demonstrate a novel approach to detect acute deviation from steady state of an ICP dynamic system in an absence of significant mean ICP changes. We hypothesized that steady state of ICP dynamic systems is reflected as ICP pulses of similar mean ICP levels resembling each other for a given subject. A general framework was used to derive such a steady-state indicator that can accommodate different metrics of inter-pulse distance and different statistics of the distance histograms. In addition to conventional Euclidean distance and Pearson correlation, geodesic distance between pulses was introduced as a novel metric. These different ways of calculating steady-state indicators under the proposed framework were evaluated on three types of continuous ICP recordings: (1) those between two consecutive brain imaging studies that demonstrated acute ventricular enlargement for slit ventricle syndrome (SVS) patients undergoing a trial of shunt externalization and clamping (SVS+); (2) those between consecutive brain imaging studies from the SVS patients under the same trial but without ventricular enlargement (SVS-); (3) overnight recordings from normal pressure hydrocephalus (NPH) patients. It was observed that only the standard deviation of geodesic distance correctly differentiated between SVS+ and SVS- and between SVS+ and NPH while avoiding discriminating between SVS- and NPH. It was also found that 45% SVS+ cases had a multimodal geodesic distance histogram while none of SVS- and 3.8% of NPH cases had such a multimodal histogram. Pulses with a large number of distant pulses for the five multimodal-histogram SVS+ cases fell in short time windows indicating that acute ventricular changes may have occurred in these confined time windows during which no significant changes of mean ICP were observed. In contrast, the pulses with a large number of distant pulses for the two multimodal-histogram NPH cases did not cluster temporally. In conclusion, the geodesic inter-pulse distance is a promising metric to quantify distance intrinsic to the underneath geometric structure of ICP signals and hence is a more suitable way to derive a steady-state indicator of an ICP dynamic system.

Ventriculoperitoneal shunt surgery outcome in adult transition patients with pediatric-onset hydrocephalus

BACKGROUND

Ventriculoperitoneal shunting remains the most widely used neurosurgical procedure for the management of hydrocephalus, albeit with many complications.

OBJECTIVE

To review and assess the long-term clinical outcome of ventriculoperitoneal shunt surgery in adult transition patients with pediatric-onset hydrocephalus.

METHODS

Patients 17 years or older who underwent ventriculoperitoneal shunt placement for hydrocephalus during their pediatric years (younger than 17 years) were included. Medical charts, operative reports, imaging studies, and clinical follow- up evaluations were reviewed and analyzed retrospectively.

RESULTS

A total of 105 adult patients with pediatric-onset hydrocephalus were included. The median age of the patients was 25.9 years. The median age at the time of the initial ventriculoperitoneal shunt placement was 1.0 year. The median follow-up time for all patients was 17.7 years. The incidence of shunt failure at 6 months was 15.2%, and the overall incidence of shunt failure was 82.9%. Single shunt revision occurred in 26.7% of the patients, and 56.2% had multiple shunt revisions. The cause of hydrocephalus was significantly associated with shunt survival for patients who had shunt failure before the age of 17 years. Being pediatric at first shunt revision, infection, proximal shunt complication, and other causes were independently associated with multiple shunt failures.

CONCLUSION

The findings of this retrospective study show that the long-term ventriculoperitoneal shunt survival remains low in adult transition patients with pediatric-onset hydrocephalus.

Revisiting hydrocephalus as a model to study brain resilience

Hydrocephalus is an entity which embraces a variety of diseases whose final result is the enlarged size of cerebral ventricular system, partially or completely. The physiopathology of hydrocephalus lies in the dynamics of circulation of cerebrospinal fluid (CSF). The consequent CSF stasis in hydrocephalus interferes with cerebral and ventricular system development. Children and adults who sustain congenital or acquired brain injury typically experience a diffuse insult that impacts many areas of the brain. Development and recovery after such injuries reflects both restoration and reorganization of cognitive functions. Classic examples were already reported in literature. This suggests the presence of biological mechanisms associated with resilient adaptation of brain networks. We will settle a link between the notable modifications to neurophysiology secondary to hydrocephalus and the ability of neuronal tissue to reassume and reorganize its functions.

Ten years of clinical experience in the use of fixed-pressure versus programmable valves: a retrospective study of 159 patients

AIM

The aim of this study was to present our 10-year experience with the use of fixed-pressure and programmable valves in the treatment of adult patients requiring cerebrospinal fluid (CSF) diversion.

MATERIAL AND METHODS

Patients (n = 159; 89 male and 70 female) suffering from hydrocephalus of various causes underwent CSF shunt implantation. Forty fixed-pressure and 119 programmable valves were initially implanted.

RESULTS

The observed revision rate was 40% in patients with fixed-pressure valves. In 20% of these patients, a revision due to valve mechanism malfunction was undertaken, and the initial valve was replaced with a programmable one. The revision rate in the adjustable-pressure valve subgroup was 20%. The infection rate for the fixed-pressure and programmable valve subgroups were 3%, and 1.7%, respectively. Similarly, subdural fluid collections were noticed in 17% and 4% of patients with fixed-pressure valves and programmable valves, respectively.

CONCLUSIONS

The revision and over-drainage rates were significantly lower when using programmable valves, and thus, this type of valve is preferred whenever CSF has to be diverted.

Treatment of hydrocephalus with ventriculoperitoneal shunting in twelve dogs

OBJECTIVE

To report use of ventriculoperitoneal shunt in dogs for management of hydrocephalus for which no cause could be identified.

STUDY DESIGN

Case series.

ANIMALS

Dogs with hydrocephalus (n=12).

METHODS

Medical records (June 2003-June 2009) were reviewed to determine preoperative clinical findings, initial postoperative, and long-term outcome. Additional follow-up information was obtained from owners and referring veterinarians.

RESULTS

All dogs had signs of forebrain dysfunction, 7 had vestibular signs and 3 had signs of spinal pain. Postoperative complications included pain (n=4), undershunting because of shunt kinking (n=1) and seizures (n=1). Initial improvement occurred in all dogs and was sustained in 9 dogs, 1 of which required revision surgery.

CONCLUSIONS

Sustained clinical improvement can be achieved in hydrocephalus with no active underlying cause by use of ventriculoperitoneal shunting.