Application of endoscopic third ventriculostomy for treating hydrocephalus-correlated Chiari type I malformation in a single Chinese neurosurgery centre

Preoperative estimation of intracranial compliance in symptomatic children with Chiari malformation type 1: impact on outcome and risk of complications

BACKGROUND

The role of reduced intracranial compliance (ICC) in the outcome after foramen magnum decompression (FMD) was demonstrated in adults with Chiari malformation Type 1 (CMI). However, similar observations from children treated for CMI are missing.

METHODS

We reviewed pediatric cases of CMI referred to FMD between 2006 and 2022. Children with clinical and/or radiological signs suggesting reduced ICC (Group A) underwent overnight measurements of the pulsatile intracranial pressure (ICP): mean ICP wave amplitude (MWA) served as a surrogate marker of ICC. Children with more typical symptoms of CMI (Group B) underwent FMD without preoperative ICC estimation. This study presents the clinical, radiological, and outcome differences between these groups.

RESULTS

Sixty-four children (mean age 11.1 ± 4.3 years) underwent FMD: In Group A (n = 30), the finding of reduced ICC as estimated from preoperative ICP measurement resulted in CSF diversion (ventriculoperitoneal shunt) before FMD in 11 children. Two patients required shunt due to complications after FMD (total shunt rate 43%). In Group B (n = 34) treated with FMD without preoperative ICC estimation, five children (15%) required shunting due to complications. In Group A, we found a significantly higher frequency of headache, nausea, fatigue, and dizziness. The outcome assessed by the modified Chicago Chiari Outcome Scale (mean follow-up 83 ± 57 months) was comparable between the groups, but the complication rate after FMD was significantly lower in Group A (7% vs. 32%; p = 0.011). The number of procedures (ICP measurement, FMD, shunt, re-do FMD, shunt revisions) was significantly higher in Group A (2.6 ± 0.9 vs. 1.5 ± 1.1 per patient; p < 0.001).

CONCLUSION

In symptomatic children with CMI, the preoperative estimation of ICC from the overnight measurement of pulsatile ICP was more reliable for identifying those with reduced ICC than clinical and radiological assessment alone. When children with abnormally reduced ICC were identified and treated with CSF diversion before FMD, the complication rate was significantly reduced.

Factors affecting endoscopic third ventriculostomy success in adults

BACKGROUND

Endoscopic third ventriculostomy (ETV) is a standard treatment in hydrocephalus of certain aetiologies. The most widely used predictive model is the ETV success score. This is frequently used to predict outcomes following ETV in adult patients; however, this was a model developed in paediatric patients with often distinct aetiologies of hydrocephalus. The aim of this study was to assess the predictive value of the model and to identify factors that influence ETV outcomes in adults.

METHODS

A retrospective study design was used to analyse consecutive patients who underwent ETV at a tertiary neurosurgical centre between 2012 and 2020. Observed ETV outcomes at 6 months were compared to pre-operative predicted ETV success scores. A multivariable Bayesian logistic regression analysis was used to determine the factors that best predicted ETV success and those factors that were redundant.

RESULTS

A total of 136 patients were analysed during the 9-year study. Thirty-one patients underwent further cerebrospinal fluid diversion within 6 months. The overall ETV success rate was 77%. Observed ETV outcomes corresponded well with predicted outcomes using the ETV success score for the higher scores, but less well for lower scores. Location of obstruction at the aqueduct irrespective of aetiology was the best predictor of success with odds of 1.65 of success. Elective procedures were also associated with higher success compared to urgent ones, whereas age under 70, nature and location of obstructive lesion (other than aqueductal) did not influence ETV success.

CONCLUSION

ETV was successful in three-quarters of adult patient with hydrocephalus within 6 months. Obstruction at the level of the aqueduct of any aetiology was a good predictor of ETV success. Clinicians should bear in mind that adult hydrocephalus responds differently to ETV compared to paediatric hydrocephalus, and more research is required to develop and validate an adult-specific predictive tool.

Endoscopic third ventriculostomy for the management of children with cerebrospinal fluid disorders, ventriculomegaly, and associated Chiari I malformation

OBJECTIVES

Our objective was to review the outcomes of children with CIM and associated cerebrospinal fluid (CSF) disorders and ventriculomegaly undergoing endoscopic third ventriculostomy (ETV) as a primary intervention.

MATERIALS AND METHODS

A retrospective, single-center, observational cohort study was conducted of consecutive children with CIM with associated CSF disorders and ventriculomegaly treated first by ETV between January 2014 and December 2020.

RESULTS

Raised intracranial pressure symptoms were the most frequent in ten patients, followed by posterior fossa and syrinx symptoms in three cases. One patient had a later stoma closure and required a shunt insertion. The success rate of the ETV in the cohort was 92% (11/12). There was no surgical mortality in our series. No other complications were reported. The median herniation of the tonsils was not statistically different in the pre vs. post-operative MRI (1.14 vs. 0.94, p=0.1). However, the median Evan's index (0.4 vs. 0.36, p<0.01) and the median diameter of the third ventricle (1.35 vs. 0.76, p<0.01) were statistically different between the two measurements. The preoperative length of the syrinx did not change significantly compared with the postoperative (5 vs. 1; p=0.052); nevertheless, the median transverse diameter of the syrinx did improve significantly after the surgery (0.75 vs. 0.32, p=0.03).

CONCLUSIONS

Our study supports ETV's safety and effectiveness for managing children with CSF disorders, ventriculomegaly, and associated CIM.

Endoscopic third ventriculostomy for management of hydrocephalus associated with Chiari malformation type II in children

BACKGROUND

Hydrocephalus is commonly associated with Chiari malformation (CM) particularly CM type II. The traditional treatment of hydrocephalus in these patients has been cerebrospinal fluid diversion by shunts. Endoscopic third ventriculostomy (ETV) has emerged as an alternative procedure in these patients.

PURPOSE

Assessment of the clinical and radiological outcomes of ETV in the management of hydrocephalus in children with CM II.

METHODS

This is a prospective study conducted on 18 patients with CM II associated with hydrocephalus admitted to Cairo University hospitals between January 2020 and June 2021. These patients had been managed surgically by ETV. Clinical outcome was assessed based on improvement of manifestations of increased intracranial pressure while radiological outcome was based on the findings of postoperative computed tomography. In cases with early failure, serial lumbar puncture (LP) was performed for 2 days.

RESULTS

ETV was performed as a secondary procedure in 4 cases. The overall success rate of the procedure was 72%, and its success rate as a secondary procedure was 100%. Serial LP was effective in decreasing early failure in 44.4% of cases. Radiological regression of hydrocephalic changes was detected in 50% of the cases.

CONCLUSION

ETV is an efficient and safe procedure in the treatment of hydrocephalus in children with Chiari malformation II, particularly when performed as a secondary procedure. Serial LP following the procedure increases the success rate in patients with early failure.

Posterior fossa decompression for children with Chiari I malformation and hydrocephalus

INTRODUCTION

Chiari I malformation (CMI) and hydrocephalus often coexist, with no clear understanding of the cause-and-effect relationship. In the absence of other associated etiologies, the traditional teaching has been to treat the hydrocephalus first, partly to minimize the risk of cerebrospinal fluid (CSF) leak from CMI decompression in the setting of elevated ICP. We describe a series of consecutive pediatric patients with CMI and hydrocephalus, the majority of whom were managed with posterior fossa decompression.

METHODS

A retrospective review was conducted on consecutive children who presented to the senior author with both hydrocephalus and CMI, with emphasis on rationale for and outcomes of surgical intervention, including the need for additional surgery.

RESULTS

There were 14 patients aged 2 weeks to 16 years (median 2 years) who presented with Chiari I and hydrocephalus. Four of these underwent posterior fossa decompression without duraplasty (PFD) as first-line therapy (one of whom eventually required duraplasty), 7 had PFD with duraplasty (PFDD), 1 received a ventriculoperitoneal shunt (VPS), and two had endoscopic third ventriculostomy (ETV). Of the 11 who had PFD/D, 9 (90%) had significant symptom improvement/resolution, 7 (55%) showed decrease in ventricle size, and 1 (10%) required VPS placement for persistent hydrocephalus. Both ETV patients improved clinically, and 1 showed decrease in ventricle size. There were no pseudomeningoceles, infections, or neurological deficits. One CSF leak occurred after an ETV and was successfully treated with wound revision.

CONCLUSION

In patients with both CMI and hydrocephalus, treating the CMI first in an effort to avoid a shunt can be safe and effective. In this series, PFDD in the setting of hydrocephalus did not result in CSF leak or pseudomeningocele. While limited by a small sample size, these data support a causative relationship between CMI and hydrocephalus.

Efficacy and safety of flexible versus rigid endoscopic third ventriculostomy in pediatric and adult populations: a systematic review and meta-analysis

Endoscopic third ventriculostomy (ETV) is a well-established surgical procedure for hydrocephalus treatment, but there is sparse evidence on the optimal choice between flexible and rigid approaches. A meta-analysis was conducted to compare efficacy and safety profiles of both techniques in pediatrics and adults. A comprehensive search was conducted on PubMED, EMBASE, and Cochrane until 11/10/2019. Efficacy was evaluated comparing incidence of ETV failure, while safety was defined by the incidence of perioperative complications, intraoperative bleedings, and deaths. Random-effects models were used to pool the incidence. Out of 1365 studies, 46 case series were meta-analyzed, yielding 821 patients who underwent flexible ETV and 2918 who underwent rigid ETV, with an age range of [5 days–87 years]. Although flexible ETV had a higher incidence of failure in adults (flexible: 54%, 95%CI: 22–82% vs rigid: 20%, 95%CI: 22–82%) possibly due to confounding due to etiology in adults treated with flexible, a smaller difference was seen in pediatrics (flexible: 36%, pediatric: 32%). Safety profiles were acceptable for both techniques, with a certain degree of variability for complications (flexible 2%, rigid 18%) and death (flexible 1%, rigid 3%) in pediatrics as well as complications (rigid 9%, flexible 13%), death (flexible 4%, rigid 6%) and intra-operative bleeding events (rigid 6%, flexible 8%) in adults. No clear superiority in efficacy could be depicted between flexible and rigid ETV for hydrocephalus treatment. Safety profiles varied by age but were acceptable for both techniques. Well-designed comparative studies are needed to assess the optimal endoscopic treatment option for hydrocephalus.

Endoscopic third ventriculostomy for treatment of tonsillar descent with hydrocephalus: CSF flow dynamics and treatment strategies

OBJECTIVE

To explore the role of cerebrospinal fluid (CSF) flow dynamics and develop treatment strategies involving endoscopic surgery for tonsillar descent with hydrocephalus.

METHODS

This study included 15 patients with tonsillar descent with hydrocephalus. All patients underwent cine-magnetic resonance imaging (MRI) preoperatively to measure CSF flow at the entrance of the cerebral aqueduct and foramen of Magendie. Endoscopic third ventriculostomy (ETV) was performed.

RESULTS

All patients exhibited abnormal CSF flow dynamics at Magendie's foramen prior to surgery. After surgery, cine-MRI showed CSF flow through the ventriculostomy. During the follow-up period of 8-72 months, the level of tonsillar descent reduced in 9 patients, and the spinal cord syrinx was reduced in 1 patient. Clinical symptoms were improved in 14 patients. Secondary endoscopically assisted posterior cranial fossa decompression was performed in one patient whose symptoms were not improved after ETV. In no case was secondary ventriculo-peritoneal shunting performed following primary ETV.

CONCLUSION

ETV is a low-risk and effective method that can replace ventriculo-peritoneal shunt placement in the treatment of tonsillar descent with obstructive hydrocephalus. Preoperative cine-MRI of CSF flow dynamics in the aqueduct and Magendie's foramen provides valuable information for determining surgical timing and strategies.

Chiari type I and hydrocephalus

PURPOSE

The association between Chiari type I malformation (CIM) and hydrocephalus raises a great interest because of the still unclear pathogenesis and the management implications. The goal of this paper is to review the theories on the cause-effect mechanisms of such a relationship and to analyze the results of the management of this condition.

METHODS

A review of the literature has been performed, focusing on the articles specifically addressing the problem of CIM and hydrocephalus and on the series reporting about its treatment. Also, the personal authors' experience is briefly discussed.

RESULTS

As far as the pathogenesis is concerned, it seems clear that raised intracranial pressure due to hydrocephalus can cause a transient and reversible tonsillar caudal ectopia ("pressure from above" hypothesis), which is something different from CIM. A "complex" hypothesis, on the other hand, can explain the occurrence of hydrocephalus and CIM because of the venous engorgement resulting from the hypoplasia of the posterior cranial fossa (PCF) and the occlusion of the jugular foramina, leading to cerebellar edema (CIM) and CSF hypo-resorption (hydrocephalus). Nevertheless, such a mechanism can be advocated only in a minority of cases (syndromic craniosynostosis). In non-syndromic CIM subjects, the presence of hydrocephalus could be explained by an occlusion of the basal CSF pathways, which would occur completely in a minority of cases (only 7-10% of CIM patients show hydrocephalus) while it would be partial in the remaining cases (no hydrocephalus). This hypothesis still needs to be demonstrated. As far as the management is concerned, the strategy to treat the hydrocephalus first is commonly accepted. Because of the "obstructive" origin of CIM-related hydrocephalus, the use of endoscopic third ventriculostomy (ETV) is straightforward. Actually, the analysis of the literature, concerning 63 cases reported so far, reveals very high success rates of ETV in treating hydrocephalus (90.5%), CIM (78.5%), and syringomyelia symptoms (76%) as well as in giving a radiological improvement of both CIM (74%) and syringomyelia (89%). The failures of ETV were not attributable to CIM or syringomyelia. Only 11% of cases required PCF decompression after ETV.

CONCLUSIONS

The association between CIM and hydrocephalus probably results from different, multifactorial, and not yet completely understood mechanisms, which place the affected patients in a peculiar subgroup among those constituting the heterogeneous CIM population. ETV is confirmed as the best first approach for this subset of patients.

The Chiari I malformation

As with many pathologies, the course of our understanding of the Chiari I malformation (CIM) has developed extensively over time. The early descriptions of the Chiari malformations by Hans Chiari in 1891 opened the door for future classification and research on this topic. However, even over a long timeframe, our understanding of the pathophysiology and, more importantly, treatment, remained in its infancy. As recently as the 1970s, CIM was not discussed in popular neurology textbooks. Syringomyelia is listed as a degenerative disorder with no satisfactory treatment. Radiation therapy was considered an option in treatment, and surgery was thought to play no role. During the last 40 years, equivalent to the duration of a neurosurgical career, our understanding of the pathophysiology and natural history of CIM, coupled with modern MRI, has improved the treatment paradigm for this patient population. More importantly, it has given us evidence confirming that CIM is a disorder responsive to surgical intervention, giving patients once thought to be destined for lifelong disability a comparatively normal life after treatment. The purpose of this article is to offer a review of CIM and its important associated entities. The authors will discuss the evolution in understanding of the Chiari malformation and, importantly, distinguish between symptomatic CIM and asymptomatic tonsillar ectopia, based on imaging and presenting symptomatology. They will discuss techniques for surgical intervention, expected outcomes, and complications after surgery. Proper patient selection for surgery based on appropriate symptomatology is tantamount to achieving good surgical outcomes in this population, separating those who can be helped by surgery from those who are unlikely to improve. While our knowledge of the Chiari malformations continues to improve through the efforts of clinical and basic science researchers, surgeons, and patients, our current understanding of these entities represents a monumental improvement in patient care over a relatively short time period.