Long-term operative failure of endoscopic third ventriculostomy in pediatric patients: the role of cine phase-contrast MR imaging

Compare the safety and efficacy of endoscopic third ventriculostomy and ventriculoperitoneal shunt placement in infants and children with hydrocephalus: a systematic review and meta-analysis

PURPOSE

Endoscopic third ventriculostomy (ETV) and ventriculoperitoneal shunt placement are two surgical options used for treatment of non-communicating hydrocephalus. The purpose of this study was to compare the efficiency and safety of these techniques in pediatric patients.

MATERIALS AND METHODS

An extensive literature review regarding the clinical outcome, safety and efficiency of ETV and shunting in treatment of hydrocephalus was conducted in Medline, PubMed, Cochrane and Google Scholar databases up to 27 November 2015. Patient demographics, ETV and shunting success and failure rates were extracted.

RESULTS

A total of seven two-arm studies were included for quantitative analysis and 25 single-arm studies were included for systematic review. The two-arm studies recruited a total of 6995 patients: 1046 in the ETV group and 5949 in the shunt group. The pooled results showed that the 1 year success rate of ETV and shunt-placement procedure were similar (pooled RR = 0.870, 95% CI = 0.680-1.112, P = 0.266). The failure rate in the ETV treatment group was 0.9 times higher than in the shunt group; however, the results did not reach statistical significance (pooled RR = 0.893, 95% CI = 0.576-1.383, P = 0.611).

CONCLUSIONS

Both ETV and shunts are associated with similar 1 year success and failure rates. Therefore, there are no current indications to recommend one mode of treatment over the other. Future studies designed to assess the effectiveness of ETV and shunt procedures depending on patient's age and etiology are warranted.

Spontaneous Third Ventriculostomy in Cases of Aqueductal Stenosis: A Retrospective Case Series

BACKGROUND

Spontaneous third ventriculostomy (STV) is a rare occurrence in cases of obstructive hydrocephalus where the walls of the third ventricle rupture, communicating the ventricular system, and the subarachnoid space leading to arrest of active hydrocephalus. We aim to review our series of STVs while reviewing previous reports.

METHODS

A retrospective review of cases undergoing cine phase-contrast magnetic resonance imaging (PC-MRI) from 2015 to 2022 of any age with imaging evidence of arrested obstructive hydrocephalus was performed. Patients in which aqueductal stenosis was radiologically evident and the presence of third ventriculostomy through which cerebrospinal fluid flow was detectable were included. Patients who previously underwent endoscopic third ventriculostomy were excluded. Data on patient demographics, presentation, and imaging details of STV and aqueductal stenosis were collected. We searched the PubMed database using the following keyword combination: ((("spontaneous ventriculostomy") OR ("spontaneous third ventriculostomy")) OR ("spontaneous ventriculocisternostomy")) including English reports of STV published between 2010 and 2022.

RESULTS

Fourteen cases were included (7 adults, 7 pediatrics), all with history of hydrocephalus. STV occurred in the floor of the third ventricle in 57.1% of the cases, at the lamina terminalis in 35.7%, and at both sites in 1 case. Eleven publications reporting 38 cases of STV were identified from 2009 to date. Minimum follow-up period was 10 months and maximum follow-up is 77 months.

CONCLUSIONS

In cases of chronic obstructive hydrocephalus, neurosurgeons should be minded with the possibility of the presence of an STV on cine phase-contrast magnetic resonance imaging leading to arrested hydrocephalus. The delayed flow at the aqueduct of Sylvius might not be the only determinant of the necessity of cerebrospinal fluid diversion and the presence of an STV should be factored into the neurosurgeon's decision considering the patient's clinical picture.

Comparative Outcome Analysis of Endoscopic Third Ventriculostomy and Ventriculoperitoneal Shunt Surgery in Pediatric Hydrocephalus: An Experience of a Tertiary Care Center

Background  Endoscopic third ventriculostomy (ETV) and ventriculoperitoneal shunt surgery (VPS) are used for the surgical management of pediatric hydrocephalus. There is controversy regarding the safety and efficacy of these procedures according to age, etiologies, and type of hydrocephalus.

Objective  The purpose of this study was to compare the outcomes and complications of ETV and VPS in pediatric hydrocephalus and to evaluate the better procedure.

Material and Methods  We retrospectively analyzed the pediatric hydrocephalus cases that were operated by ETV and VPS at our department from June 2016 to June 2019. Data were analyzed with respect to the etiology of hydrocephalus, age, and gender of the patients. We compared the outcomes (success and failure) depending on age at surgery, etiology, and type of hydrocephalus, complications at 12 months of follow-up. Fisher's exact test and chi-square test were applied to test the significance of difference.

Results  There were 195 pediatric hydrocephalus cases, which were operated by ETV ( n  = 43; 22.05%) and VPS ( n  = 152; 77.95%). The mean age of the cases was 53.63 ± 60.24 (ranged 0.5–204 months) in the ETV group and 53.44 ± 54.10 (ranged 0.3–210 months) in the VPS group. The male-to-female ratio was 1.41:1 in the ETV group and 1.21: 1 in the VPS group. Overall, ETV had successful outcomes in 30(69.77%) cases and VPS in 102(67.11%) cases at 12 months of follow-up. The complication rates were found in 7 (16.28%) cases in the ETV group and 38 (25.0%) cases in the VPS group. At initial 0.5 months of follow-up, ETV required revisions in 6 (13.95%) cases and VPS in 15 (9.87%) cases.

Conclusion  Although the success and failure of both the procedure vary according to the age at surgery, etiology and type of hydrocephalus, and complications, and failure rates on follow-up, there were no statistically significant differences between the two surgical groups in respect to these variables.

Failure of Endoscopic Third Ventriculostomy

Endoscopic third ventriculostomy (ETV) is an alternative to cerebrospinal fluid (CSF) shunting in the treatment of hydrocephalus. Careful patient selection is critical as patient age, etiology of hydrocephalus, and previous shunting have been shown to influence ETV success rates. Intraoperatively, patient anatomy and medical stability may prevent or limit the completion of the ventriculostomy procedure, and findings such as a patulous third ventricular floor or cisternal scarring may portend a lower chance of successful hydrocephalus treatment. Patients in whom a ventriculostomy is completed may still experience continued symptoms of hydrocephalus or CSF leak, representing an early ETV failure. In other patients, the ETV may prove a durable treatment of hydrocephalus for several months or even years before recurrence of hydrocephalus symptoms. The failure pattern for ETV is different than that of shunting, with a higher early failure rate but improved long-term failure-free survival rates. The risk factors for failure, along with the presentation and management of failure, deserve review.

Hydrocephalus Study Design: Testing New Hypotheses in Clinical Studies and Bench-to-Bedside Research

In this article, we aimed to describe some of the currently most challenging problems in neurosurgical management of hydrocephalus and how these can be reasons for inspiration for and development of research. We chose 4 areas of focus: 2 dedicated to improvement of current treatments (shunt implant surgery and endoscopic hydrocephalus surgery) and 2 dedicated to emerging future treatment principles (molecular mechanisms of cerebrospinal fluid secretion and hydrocephalus genetics).

The Role of Early Postoperative Intracranial Pressure Monitoring in Predicting the Outcome of Endoscopic Third Ventriculostomy Performed in Infants With Congenital Hydrocephalus: A Prospective Analysis

Introduction

Hydrocephalus is an excessive accumulation of cerebrospinal fluid (CSF) in the cavity and spaces of the brain. To date, there is no single method to accurately assess the compliance of subarachnoid spaces after endoscopic third ventriculostomy (ETV).

Objective

To analyze the intracranial pressure (ICP) trends in the early postoperative period in infants undergoing ETV for congenital hydrocephalus and correlate them with the final outcome.

Material and methods

This is a single-center prospective study conducted at the Department of Neurosurgery of our institute from January 2019 to February 2020. Infants presented with congenital hydrocephalus mandating ETV were included in the study. ICP was continuously monitored for the first three days after the procedure. ICP values were recorded hourly, and 24 ICP values obtained daily were averaged to obtain a daily average value (DAV).

Results

Forty patients were recruited in the study. The mean age of the study population was 4.7 ± 2.8 months; 80% of the infants were <6 months of age. The male/female ratio was 5.7:1. The most common etiology was congenital aqueductal stenosis, which was observed in 18 (45%) of the patients, followed by Dandy-Walker malformation (DWM) in 11 (27.5%) of the patients. On considering a difference of >1 mmHg between the first and third postoperative day, the ETV success rate was dropped from 50% in stable trend to 11% in progressive increase trend, which was statistically significant (p = 0.044). At DAV variation of >2 mmHg in progressive increase trend, the sensitivity of stable ICP trend increased to 100% in predicting ETV success. Also, the negative predictive value (the ability of a stable trend to rule out ETV failure) reached 100%. The overall success rates of ETV in our study at one, three, and six months were 62.5%, 40%, and 35%, respectively.

Conclusion

A progressive increase in the ICP trend (with a difference of >2 mmHg between postoperative days 1 and 3) was the best predictor of ETV failure in our study. It was superior to any other clinical or radiological variable in our study, which was affecting the outcome.

Advanced Magnetic Resonance Imaging of the Skull Base

Magnetic resonance (MR) imaging is a crucial tool for evaluation of the skull base, enabling characterization of complex anatomy by utilizing multiple image contrasts. Recent technical MR advances have greatly enhanced radiologists' capability to diagnose skull base pathology and help direct management. In this paper, we will summarize cutting-edge clinical and emerging research MR techniques for the skull base, including high-resolution, phase-contrast, diffusion, perfusion, vascular, zero echo-time, elastography, spectroscopy, chemical exchange saturation transfer, PET/MR, ultra-high-field, and 3D visualization. For each imaging technique, we provide a high-level summary of underlying technical principles accompanied by relevant literature review and clinical imaging examples.

Gelfoam Migration: A Potential Cause of Recurrent Hydrocephalus

BACKGROUND

Gelfoam is a simple and effective hemostatic agent that is used to seal brain corticotomies or skull burr holes. Owing to its low cost, it is one of the most widely used tools in neurosurgical daily practice. However, migration of Gelfoam fragments can cause occlusion of endoscopic third ventriculostomy (ETV) or shunt, leading to hydrocephalus recurrence.

CASE DESCRIPTION

Two cases of Gelfoam migration causing recurrent hydrocephalus are presented: a 12-year-old girl who underwent surgery for posterior fossa tumor removal and ETV for associated hydrocephalus, where a portion of Gelfoam (used to seal the burr hole) migrated up to close the ETV, and a preterm 8-month-old boy who was treated by neuroendoscopic brain lavage and afterward by ventriculoperitoneal shunt for posthemorrhagic hydrocephalus, where all the Gelfoam used to close the corticotomy migrated into the lateral ventricle, thus reopening the corticotomy and releasing small fragments that ultimately obstructed the shunt. A new endoscopic procedure was required in both patients (the second patient also required a shunt revision).

CONCLUSIONS

Review of the pertinent literature discloses other complications of Gelfoam migration (e.g., mass effect, granulomatous reaction) as well as other causes of uncommon ETV/shunt obstruction. Nonetheless, Gelfoam will remain an indispensable tool for neurosurgeons. The present report emphasizes the importance of its correct use to avoid complications.

Neurogenic Bladder Dysfunction as Signal of Late Failure of Endoscopic Third Ventriculostomy in Child with Spina Bifida

BACKGROUND

Endoscopic third ventriculostomy (ETV) is an option for hydrocephalus treatment in patients with myelomeningocele, mostly after a previous shunt dysfunction. Late failure of ETV is a rare event, traditionally associated with dramatic symptoms of intracranial hypertension. In patients with myelodysplasia and neurogenic bladder dysfunction, urodynamic deterioration can be a signal of neurologic worsening as a consequence of tethered cord or shunt problems.

CASE DESCRIPTION

We describe here a rare case of a 12-year-old female patient with myelomeningocele and evidence of a failure 10 years after a previously successful ETV whose initial symptoms were worsening of urinary complaints. After 2 months, she was admitted to the emergency department with seizures and acute hydrocephalus and was shunted.

CONCLUSIONS

Pediatric neurosurgeons must follow myelomeningocele patients with successful ETV for a long time and take care of subtle alterations of organic functions that have a close relationship with central nervous system integrity. A multidisciplinary approach can facilitate this strategy and avoid a tragic outcome.

Higher Failure of Endoscopic Third Ventriculostomy in Infants: The "Distensible" Skull Is the Culprit

The efficacy of endoscopic third ventriculostomy (ETV) in childhood strongly correlates with age. Reasons for the higher failure rate in infants are under debate but the "distensible" head with its immature skull (which would prevent an adequate flow through the ETV and/or a sufficient pressure gradient between the cortical subarachnoid spaces and the venous sinuses) has been suggested as a possible cause. Our evidence of spontaneous conversion of a failed, but always patent, third ventriculostomy into an effective one occurring in a child after maturation of the skull supports this hypothesis.

The effect and evolution of patient selection on outcomes in endoscopic third ventriculostomy for hydrocephalus: A large-scale review of the literature

Endoscopic third ventriculostomy (ETV) has become a popular technique for the treatment of hydrocephalus, but small sample size has limited the generalizability of prior studies. We performed a large-scale review of all available studies to help eliminate bias and determine how outcomes have changed and been influenced by patient selection over time. A systematic literature search was performed for studies of ETV that contained original, extractable patient data, and a meta-analytic model was generated for correlative and predictive analysis. A total of 130 studies were identified, which included 11,952 cases. Brain tumor or cyst was the most common hydrocephalus etiology, but high-risk etiologies, post-infectious or post-hemorrhagic hydrocephalus, accounted for 18.4%. Post-operative mortality was very low (0.2%) and morbidity was only slightly higher in developing than in industrialized countries. The rate of ETV failure was 34.7% and was higher in the first months and plateaued around 20months. As anticipated, ETV is less successful in high-risk etiologies of hydrocephalus and younger patients. Younger patient age and high-risk etiologies predicted failure. ETVs were performed more often in high-risk etiologies over time, but, surprisingly, there was no overall change in ETV success rate over time. This study should help to influence optimal patient selection and offer guidance in predicting outcomes.

Endoscopic third ventriculostomy and repeat endoscopic third ventriculostomy in pediatric patients: the Dutch experience

OBJECTIVE After endoscopic third ventriculostomy (ETV), some patients develop recurrent symptoms of hydrocephalus. The optimal treatment for these patients is not clear: repeat ETV (re-ETV) or CSF shunting. The goals of the study were to assess the effectiveness of re-ETV relative to initial ETV in pediatric patients and validate the ETV success score (ETVSS) for re-ETV. METHODS Retrospective data of 624 ETV and 93 re-ETV procedures were collected from 6 neurosurgical centers in the Netherlands (1998-2015). Multivariable Cox proportional hazards modeling was used to provide an adjusted estimate of the hazard ratio for re-ETV failure relative to ETV failure. The correlation coefficient between ETVSS and the chance of re-ETV success was calculated using Kendall's tau coefficient. Model discrimination was quantified using the c-statistic. The effects of intraoperative findings and management on re-ETV success were also analyzed. RESULTS The hazard ratio for re-ETV failure relative to ETV failure was 1.23 (95% CI 0.90-1.69; p = 0.20). At 6 months, the success rates for both ETV and re-ETV were 68%. ETVSS was significantly related to the chances of re-ETV success (τ = 0.37; 95% bias corrected and accelerated CI 0.21-0.52; p < 0.001). The c-statistic was 0.74 (95% CI 0.64-0.85). The presence of prepontine arachnoid membranes and use of an external ventricular drain (EVD) were negatively associated with treatment success, with ORs of 4.0 (95% CI 1.5-10.5) and 9.7 (95% CI 3.4-27.8), respectively. CONCLUSIONS Re-ETV seems to be as safe and effective as initial ETV. ETVSS adequately predicts the chance of successful re-ETV. The presence of prepontine arachnoid membranes and the use of EVD negatively influence the chance of success.

Hydrocephalus in children

Hydrocephalus is a common disorder of cerebral spinal fluid (CSF) physiology resulting in abnormal expansion of the cerebral ventricles. Infants commonly present with progressive macrocephaly whereas children older than 2 years generally present with signs and symptoms of intracranial hypertension. The classic understanding of hydrocephalus as the result of obstruction to bulk flow of CSF is evolving to models that incorporate dysfunctional cerebral pulsations, brain compliance, and newly characterised water-transport mechanisms. Hydrocephalus has many causes. Congenital hydrocephalus, most commonly involving aqueduct stenosis, has been linked to genes that regulate brain growth and development. Hydrocephalus can also be acquired, mostly from pathological processes that affect ventricular outflow, subarachnoid space function, or cerebral venous compliance. Treatment options include shunt and endoscopic approaches, which should be individualised to the child. The long-term outcome for children that have received treatment for hydrocephalus varies. Advances in brain imaging, technology, and understanding of the pathophysiology should ultimately lead to improved treatment of the disorder.

Neurosurgical training with simulators: a novel neuroendoscopy model

PURPOSE

The aim of this study is to present a novel neuroendoscopy simulation model in live animals, with the objective of enhancing patient safety with realistic surgical training.

METHODS

A simulation model using live Wistar rats was designed after the approval of the Institutional Committee for the Care and Use of Laboratory Animals. Under anesthesia, a hydroperitoneum was created in order to simulate a cavity with mesenteric membranes and vessels, viscera, and a solid and bleeding tumor (the liver) floating in a liquid environment. For validation purposes, we evaluated trainees' basal and final skills for each neuroendoscopic procedure, and we also acknowledged trainees' and instructors' opinion on the model's realism.

RESULTS

This model is simple and low cost effective for complete and real-life training in neuroendoscopy, with the possibility of performing all the basic and advanced endoscopic procedures, such as endoscopic exploration, membrane fenestration, vessel coagulation, hematoma evacuation, and endoscopic tumor biopsy and resection using a ventricular neuroendoscopy set. Although the model does not represent human ventricular anatomy, a reliable simulation is possible in real living tissue in a liquid environment. Trainees' skills improvements were notorious.

CONCLUSION

Minimally invasive endoscopic techniques require specific training. Simulation training can improve and accelerate the learning curve. The presented training model allows simulating the different neuroendoscopic procedures. We believe that due to its practical possibilities, its simplicity, low cost, reproducibility, and reality, being live animal tissue, it can be considered a fundamental model within a complete training program on neuroendoscopy.

The Use of an Aspirating/Resecting Device to Reduce Stoma Closure Following Endoscopic Third Ventriculostomy for Aqueductal Stenosis

BACKGROUND

Endoscopic third ventriculostomy (ETV) is commonly used to treat obstructive hydrocephalus. Closure of the stoma can be associated with symptom recurrence and need for further surgical intervention.

OBJECTIVE

To describe the use of a side-cutting aspiration device for treatment of aqueductal stenosis in patients undergoing ETV.

METHODS

A retrospective review of 30 consecutive adults with aqueductal stenosis treated with ETV using an adjunct side-cutting aspiration device between 2011 and 2013 was performed. Patients included in the study ranged from 35 to 64 years of age. ETV success was determined by the absence of stoma closure (aqueductal and cisternal flow assessed by high-resolution, gradient-echo magnetic resonance imaging), post-ETV symptom recurrence, and need for subsequent surgical intervention.

RESULTS

Patients treated by using a side-cutting aspirator had no observed stoma closure (0%) and a 10% (n = 3) rate of post-ETV symptom recurrence. Three patients (10%) demonstrated a need for surgical revision following initial ETV with the side-cutting aspirator.

CONCLUSION

Adult patients with obstructive hydrocephalus secondary to aqueductal stenosis exhibited a low rate of stoma closure with the use of a side-cutting aspiration device, and a rate of complications comparable to the known literature. Likewise, patients treated with a side-cutting aspirator may have lower symptom recurrence post-ETV and require fewer revisions in comparison with the known literature. As such, a side-cutting aspirator may be considered as a useful adjunct to traditional ETV for the treatment of obstructive hydrocephalus secondary to aqueductal stenosis.

Factors affecting surgical outcome of endoscopic third ventriculostomy in congenital hydrocephalus

Endoscopic third ventriculostomy (ETV) is an accepted modality of treatment for obstructive hydrocephalus, with good results in adult patients. However in the pediatric age group results vary from poor to similar to the adult population. This study evaluates the outcome of ETV in congenital hydrocephalus of both early and delayed presentation, and investigates factors that determine the outcome. Patients with congenital hydrocephalus who underwent ETV between January 2006 and December 2011 were retrospectively analyzed. Any conditions potentially influencing the need for redo surgery (persistent cerebrospinal fluid [CSF] leak not responding to local measures, tense fontanelle, increased ventricular size, recurrence of symptoms or radiological evidence of failure) were analyzed. A total of 102 patients with a mean age of 7.45years were included. Presenting features were increasing head circumference and delayed milestones. Ninety-eight patients had triventricular hydrocephalus due to aqueductal stenosis. Procedures performed were ETV only (n=74), ETV with aqueductoplasty (n=22), ETV with cystoventriculostomy (n=2) and aqueductoplasty only (n=2). Failure of ETV occurred in 11 patients and all were managed with a ventriculoperitoneal shunt. CSF leak in the perioperative period was the only factor that was significantly associated with failure of ETV. ETV is a safe procedure with a good success rate and can be offered to children with aqueductal stenosis. There is a higher chance of failure if there is a CSF leak in the early or late postoperative period.

Endoscopic third ventriculocisternostomy in hydrocephalic children under 2 years of age: appropriate or not? A single-center retrospective cohort study

PURPOSE

Treating hydrocephalus can be difficult in children under the age of 2 years because a high amount of uncertainty exists as to which treatment to perform. In this retrospective cohort study, we analyzed children under the age of 2 years with hydrocephalus undergoing an endoscopic third ventriculocisternostomy (ETV) with respect to ETV outcome.

METHODS

In 59 consecutive patients under the age of 2 years, an ETV was performed between 1999 and 2010 at the Erasmus MC, Sophia Children's Hospital. Demographics, etiology of hydrocephalus, and radiological data were extracted retrospectively from the patients' medical records and operative reports and related to outcome. ETV Success Score (ETVSS) was used to retrospectively calculate the probability of success related to the actual outcome.

RESULTS

In this series, 42.4 % of patients had a successful ETV. The only statistically significant finding concerned age. The failed ETV patients appeared to be younger (0.52 ± 0.60 vs. 0.86 ± 0.56 year, p = 0.005), and when using a cutoff age of 6 months only, five out of 32 infants had a successful ETV (p = 0.002). Of the children with an arachnoid cyst, 57.1 % were treated successfully with an ETV. Of the five patients with a high probability of ETV success, four (80 %) were indeed successfully treated with ETV (p = 0.049).

CONCLUSIONS

Our data confirm the overall ineffectiveness of an ETV in children under the age of 6 months. Nevertheless, using the ETVSS is recommended to aid in the decision-making process even in patients under the age of 6 months.

Time to First Shunt Failure in Pediatric Patients over 1 Year Old: A 10-Year Retrospective Study

Studies comparing alternatives to ventriculoperitoneal (VP) shunting for treatment of hydrocephalus have often relied upon data from an earlier era that may not be representative of contemporary shunt survival outcomes. We sought to determine the shunt survival rate of our cohort and compare our results to previously published shunt survival and endoscopic third ventriculostomy (ETV) success rates. We identified 95 patients between 1 and 18 years of age, who underwent initial VP shunt placement between January 2001 and December 2010. Our study shows a shunt survival rate of 85% at 6 months and 79% at 2 years, for initial shunts in pediatric patients over 1 year of age in this cohort. The overall infection rate was 3%. This compares favorably with published success rates of ETV at similar time points as well as with the rate of infection. This suggests that ventricular shunting remains a viable alternative to ETV in the older child.

Endoscopic third ventriculostomy

Endoscopic third ventriculostomy (ETV) is considered as a treatment of choice for obstructive hydrocephalus. It is indicated in hydrocephalus secondary to congenital aqueductal stenosis, posterior third ventricle tumor, cerebellar infarct, Dandy-Walker malformation, vein of Galen aneurism, syringomyelia with or without Chiari malformation type I, intraventricular hematoma, post infective, normal pressure hydrocephalus, myelomeningocele, multiloculated hydrocephalus, encephalocele, posterior fossa tumor and craniosynostosis. It is also indicated in block shunt or slit ventricle syndrome. Proper Pre-operative imaging for detailed assessment of the posterior communicating arteries distance from mid line, presence or absence of Liliequist membrane or other membranes, located in the prepontine cistern is useful. Measurement of lumbar elastance and resistance can predict patency of cranial subarachnoid space and complex hydrocephalus, which decides an ultimate outcome. Water jet dissection is an effective technique of ETV in thick floor. Ultrasonic contact probe can be useful in selected patients. Intra-operative ventriculo-stomography could help in confirming the adequacy of endoscopic procedure, thereby facilitating the need for shunt. Intraoperative observations of the patent aqueduct and prepontine cistern scarring are predictors of the risk of ETV failure. Such patients may be considered for shunt surgery. Magnetic resonance ventriculography and cine phase contrast magnetic resonance imaging are effective in assessing subarachnoid space and stoma patency after ETV. Proper case selection, post-operative care including monitoring of ICP and need for external ventricular drain, repeated lumbar puncture and CSF drainage, Ommaya reservoir in selected patients could help to increase success rate and reduce complications. Most of the complications develop in an early post-operative, but fatal complications can develop late which indicate an importance of long term follow up.

Why does endoscopic aqueductoplasty fail so frequently? Analysis of cerebrospinal fluid flow after endoscopic third ventriculostomy and aqueductoplasty using cine phase-contrast magnetic resonance imaging

OBJECT

The aim of this study was to evaluate and compare CSF flow after endoscopic third ventriculostomy (ETV) and endoscopic aqueductoplasty (EAP) in patients presenting with obstructive hydrocephalus caused by aqueductal stenosis.

METHODS

In patients harboring aqueductal stenosis who underwent EAP (n=8), ETV (n=8), and both ETV and EAP (n=6), CSF flow through the restored aqueduct and through the ventriculostomy was investigated using cine cardiac-gated phase-contrast MRI. For qualitative evaluation of CSF flow, an in-plane phase-contrast sequence in the midsagittal plane was used. The MR images were displayed in a closed-loop cine format. Quantitative through-plane measurements were performed in the axial plane perpendicular to the aqueduct and/or floor of the third ventricle.

RESULTS

Evaluation revealed significantly higher CSF flow through the ventriculostomies compared with flow through the aqueducts. This was true both when comparing the ETV group with the EAP group and when comparing the flow of the ventriculostomy and aqueduct within the ETV and EAP group. There was no difference in aqueductal CSF flow between patients who underwent EAP alone and patients who underwent ETV and EAP. There was also no difference in ventriculostomy CSF flow between patients who underwent ETV alone and patients who underwent ETV and EAP. Fifty percent of the restored aqueducts became occluded at a mean of 46 months after surgery (range 18-126 months). In contrast, all ETVs remained patent in the mean follow-up period of 110 months after surgery, although 1 patient required shunt placement after 66 months.

CONCLUSIONS

Cerebrospinal fluid flow through ventriculostomies is significantly higher than aqueductal CSF flow after EAP. This could be one factor to explain why the reclosure rate of aqueducts after EAP is higher than the reclosure rate of the ventriculostoma after ETV.