Long-Term Reliability of Neuroendoscopic Aqueductoplasty in Idiopathic Aqueductal Stenosis-Related Hydrocephalus

Advanced cerebrospinal fluid flow MRI findings of aqueductal stenosis caused by web

BACKGROUND

The aqueductal web (AW) is one of the causes of aqueductus stenosis (AS). Recent advances in Magnetic resonance (MR) imaging have enabled us to better reveal the cerebrospinal fluid (CSF) flow dynamics and aqueductal anatomy.

PURPOSE

The aim of this study is to evaluate the CSF flow dynamics of patients with AW with phase contrast Magnetic resonance imaging (MRI) and compare them with the imaging findings.

MATERIALS AND METHODS

We evaluated 23 patients under 65-year-old age. On constructive interference in steady-state (T2 CISS) images, the width of prepontine cistern (PPC) and the width of Sylvian aqueduct (SA) were measured. Localization and number of webs were evaluated. The existence of flow at the aqueduct and the presence of spontaneous third ventriculostomy (STV) were evaluated on sagittal Sampling Perfection with Application optimized Contrast (SPACE) sequences.

RESULTS

Of the 23 patients included in the study, 11 were male and 12 were female. The mean age was 34.02 (0.5-64). A total of 31 AWs were detected in 23 patients. Six of 23 patients (26.1%) had STV and 17 of those not. Four of 23 patients (17.4%) had aqueductal flow on SPACE sequences. The PPC distance was significantly wider in patients with STV (median: 6.7-4.5, interquartile range (IQR): 1.35, p = 0.004). In the cases where artifact secondary to flow is observed in SPACE sequences in aqueduct, the Evan index (EI) was significantly lower (median: 0.2955-0.3900, IQR: 0.03-0.14, p < 0.001).

CONCLUSION

In patients with a low EI, there may be flow in the SA even if there is a web. In patients with a wide PPC distance, it is necessary to consider the presence of STV and evaluate the presence of flow with the SPACE sequences.

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.

The stability of multifocal ventriculoperitoneal shunts with Y-connections

PURPOSE

Multifocal ventriculoperitoneal shunts with Y-connections (MVPS with Ys) are widely used in many centers when neuroendoscopic procedures on entrapped ventricles are not feasible; however, their use is not frequent. This study aimed to confirm the stability of an MVPS with Y and, for the first time, identify the factors that influence stability.

METHODS

We studied 33 consecutive patients who underwent initial conversion to MVPS with Ys. The one-year overall shunt survival rate was calculated and compared with the historical outcome of single ventriculoperitoneal shunts (VPSs). The factors influencing the one-year overall shunt survival rate were also investigated. The one-year survival rate for proximal catheters in each location was further investigated, and the rates were compared among locations. The factors affecting proximal catheter survival were determined.

RESULTS

The one-year overall shunt survival rate of MVPS with Y was 70%, which was not much different from that of previously reported single VPSs, including our institution. We found no significant factor influencing overall shunt survival, but when an additional catheter was inserted into the fourth ventricle, the survival rate was exceptionally low at 40% (p = 0.21). When we investigated the one-year survival rate of each proximal catheter, we found that the location of the proximal catheter showed a certain trend toward significance (p = 0.07), especially in the case of the fourth ventricle, which had the lowest survival rate at 57% and an odds ratio of 15.64 (p = 0.013) in multivariate analysis. However, when the catheter was sufficiently inserted parallel to the brain stem using navigation, the survival was relatively well maintained (1,995 to 2,547 days).

CONCLUSIONS

The stability of MVPS with Y was similar to that of single VPSs. However, the malfunction rate of the proximal catheter inserted at the fourth ventricle in the Y-connection was higher than that at other locations. The transcerebellar vertical approach or transtentorial approach parallel to the brain stem may decrease the malfunction rate.

Endoscopic aqueductoplasty and stenting in the treatment of isolated fourth ventricle in children: 20-year institutional experience

BACKGROUND

Endoscopic aqueductoplasty with aqueductal stenting is an effective surgical procedure for the treatment of isolated fourth ventricle (IFV). Due to the rarity of the underlying pathology, it can be considered a rare procedure that can be performed with different surgical techniques and approaches.

OBJECTIVES

To assess long-term functioning of permanent aqueductal stents implanted in children affected by hydrocephalus and IFV and to describe some variations of the same procedure.

METHODS

We reviewed retrospectively all the patients presenting at our institution in the years 1999-2019 for symptoms of isolated fourth ventricle who underwent a surgical procedure of endoscopic aqueductoplasty and/or aqueductal stent. Surgical reports, radiological images, and surgical videos were retrospectively analyzed.

RESULTS

Thirty-three patients with symptomatic isolated fourth ventricle (IFV) underwent fifty (50) neuroendoscopic procedures in the period observed. The median age of the patients at the time of first surgery was 7 months, with 22 premature babies. In twenty-nine patients (87.8%), a precoronal approach was performed, while four patients received a suboccipital burr hole. Ten patients were never reoperated since. Twenty-three patients underwent further surgeries: a new aqueductoplasty with aqueductal stent was performed in 13 cases. The remaining 10 patients required a combination of other procedures for management of hydrocephalus. Long-term follow-up showed a permanent stent functioning rate of 87% at 2 years and 73% at 4 years, remaining stable afterwards at very long term (20 years).

CONCLUSION

Endoscopic aqueductoplasty and stenting is a reliable procedure in the long-term management of isolated fourth ventricle.

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.