Aqueduct Stent Placement: Indications, Technique, and Clinical Experience

Endoscopic transaqueductal stent placement for tumor-related aqueductal compression in pediatric patients: surgical consideration, technique, and results

PURPOSE

Endoscopic transaqueductal stenting has become a well-accepted treatment option for a selected small subset of aqueductal stenosis-related obstructive hydrocephalus. However, transaqueductal stenting poses unique challenges and risks which requires critical consideration. This report discusses the clinical experiences with transaqueductal stenting for periaqueductal tumor-related aqueductal stenosis focusing on pediatric patients.

METHODS

A retrospective analysis of all patients undergoing endoscopic TAS from 01/1993 to 01/2022 in the author's departments was performed. Demographic, clinical, radiological, and intraoperative endoscopic data were evaluated. All patients with AS-related occlusive hydrocephalus that was treated with TAS were analyzed and prospectively followed. Special attention has been given to providing insights into indications, surgical technique, and limitations.

RESULTS

Out of 28 endoscopic transaqueductal endoscopis stenting procedures, five procedures were performed on periaqueductal tumor-related obstructive hydrocephalus, two children and three adult patients. CSF pathway was obstructed by tumor located in the aqueduct in 2, by tumor in the thalamus/mesencephalon in 1, by a tumor within the third ventricle in 1, and by a tumor of the lamina tecti in 1. Simultaneously with transaqueductal stenting, 2 endoscopic third ventriculostomies (ETV), 3 tumor biopsies, and 1 tumor resection were performed. Postoperative complications included the following: CSF fistula (1 case), and asymptomatic fornix contusion (1 case). A working aqueductal stent was achieved in all cases based on clinical follow-up evaluation. Postoperatively, all patients showed improvement or resolution of their symptoms. The mean follow-up period was 25.2 months (range, 1-108 months). One patient died due to tumor progression during early follow-up. No stent migration was seen.

CONCLUSION

Endoscopic third ventriculostomy remains the gold standard for treatment of CSF circulation obstructions with lesions in the posterior third ventricle and aqueduct. Transaqueductal stenting for periaqueductal tumor-related aqueductal compression is technically feasible. However, because of the potential high risks and subtle advantages compared with ETV transaqueductal stenting, it might be indicated in a small subset of well-selected patients if alternative treatment options are not at hand.

Trapped fourth ventricle: to stent, shunt, or fenestrate-a systematic review and individual patient data meta-analysis

Trapped or isolated fourth ventricle (TFV) is a rare but critical neurosurgical condition, mostly occurring in pediatric patients, caused by a blockage of the in- and outlets of the fourth ventricle. The purpose of this study is to review all available data on the treatment options of TFV and to compare their safety, efficacy, and durability. MEDLINE, Embase, and Google Scholar were searched from inception to September 13, 2022, for prospective or retrospective cohorts, case-control studies, case series or case reports, reporting detailing outcomes of TFV patients, treated with an endoscopic-, microsurgical-, shunt placement,- or hybrid approaches to TFV. All authors were contacted to provide individual patient data. Eighty-seven articles (314 patients) were included in the individual patient data meta-analysis (IPD) and 9 (151 patients) in the cohort meta-analysis. The IPD revealed that primary endoscopic (aOR 0.21; [95% CI 0.08-0.57]) and microsurgical interventions (aOR 0.21; [95% CI 0.05-0.82]) were associated with a significantly lower revision rate, compared to shunt placement, when adjusted for confounders. Endoscopy was also associated with a significantly higher rate of clinical improvement (aOR 4.56; [95% CI 1.2-18]). The meta-analysis revealed no significant difference in revision rate between the endoscopic (0.33 [95% CI 0.0-0.52]) and shunt group (0.44 [95% CI 0.0-1.0]). Endoscopy should be considered as the first-line treatment of TFV due to its superior efficacy, durability, and similar safety, compared to shunt placement and its minimally invasive nature. Microsurgery should be considered as a second treatment option, due to its similar clinical outcomes and revision rate as endoscopy, but it is more invasive in nature.

Endoscopic aqueductal stenting in the management of pediatric hydrocephalus

OBJECTIVE

Pediatric patients with long-term shunts may experience specific complications related to the segregation of the supra- and infratentorial spaces along with different pressure regimens, leading to either mesencephalic syndromes during shunt dysfunction or isolated fourth ventricle (IFV). An accepted treatment to reestablish normal CSF pathways and reequilibrate the transtentorial pressures is endoscopic aqueductal stenting (EAS) to avoid restenosis. In the present paper, the authors studied children treated with EAS during the last decade for both IFV and obstructive hydrocephalus, evaluated its impact on the course of the disease, and identified prognostic factors for EAS success.

METHODS

A noninterventional retrospective study of routinely acquired data was performed, including all hydrocephalic children undergoing EAS between 2011 and 2019 at Hôpital Necker, Paris, France. The following variables were analyzed: etiology of hydrocephalus; number of surgeries before and after stent placement; indication for EAS; type of stent connection (i.e., connected or not to a ventriculoperitoneal shunt); and the stent position. Stent failure was defined as the need to perform further shunt revision. Univariate and multivariate analyses were run to identify factors associated with stent failure.

RESULTS

Seventeen patients with a mean age at stent placement of 6 years (SD 6.5 years, range 1 month-18 years) and with a mean follow-up after EAS of 47.5 months (SD 33.7 months, range 5-120 months) were included in the analysis. The etiology of hydrocephalus was as follows: obstructive tumoral (41%), posthemorrhagic (35%), postinfectious (12%), and dysraphism related (12%). The indication for EAS was IFV (47%), rostral midbrain dysfunction syndrome (35%), prevention of secondary aqueductal stenosis after debulking surgery (12%), or primary aqueductal stenosis (6%). No transient or permanent neurological deficits related to the procedure were observed. After EAS, 10 patients did not require further surgeries (59%), and for the others the number of hydrocephalus-related surgeries significantly decreased after stenting. In univariate analysis posthemorrhagic etiology and prevention of aqueductal stenosis were identified as predictors of a good outcome, whereas in multivariate analysis posthemorrhagic hydrocephalus was found to predict a favorable outcome.

CONCLUSIONS

The results confirm EAS as a first-line treatment for IFV and suggest its efficacy in changing the history of hydrocephalic patients who have undergone multiple operations and who experience rostral midbrain dysfunction syndrome, as well as efficacy in the prevention of aqueductal stenosis in selected cases of obstructive tumoral hydrocephalus.

Surgical Techniques and Long-Term Outcomes of Flexible Neuroendoscopic Aqueductoplasty and Stenting in Infants with Obstructive Hydrocephalus: A Single-Center Study

OBJECTIVE

To technically review and explore long-term follow-up results of aqueductoplasty and stenting under flexible neuroendoscopy in infantile obstructive hydrocephalus.

METHODS

The clinical data, surgical techniques, and long-term effects in 14 infants with obstructive hydrocephalus treated by flexible neuroendoscopic aqueductoplasty and stenting between 2008 and 2010 were analyzed retrospectively.

RESULTS

The 14 infants had a mean age of 5.71 ± 3.10 months (range, 2-11 months) and a mean duration of follow-up of 62.64 ± 34.52 months (range, 9-121 months). Subdural effusion was observed in 4 infants (28.6%) after surgery. There were no deaths or serious complications related to intracranial stent placement. Three infants (21.4%) failed, 2 due to proximal aqueduct occlusion from a short stent length and 1 due to intraluminal ependymal adhesion obstruction. One case was abandoned when a second surgical adjustment stent was unsuccessful, and the other 2 cases went to shunt surgery.

CONCLUSIONS

Aqueductoplasty with stenting is a feasible and safe surgical procedure for treating infants with midbrain aqueduct stenosis or occlusion. However, the optimal stent material and definitive outcomes after this procedure require additional long-term follow-up studies in large numbers of infants.