Infundibular Recess Angle Reduction After Endoscopic Third Ventriculostomy: Does It Reflect Clinical Success?

The Predictive Role of Early Postoperative Magnetic Resonance Imaging After Endoscopic Third Ventriculostomy

OBJECTIVE

Endoscopic third ventriculostomy (ETV) is a treatment option for obstructive hydrocephalus; reported success rates vary. We investigated immediate postoperative magnetic resonance imaging to evaluate the role of imaging parameters associated with outcomes.

METHODS

Retrospective chart review was performed on patients undergoing initial ETV between 2005 and 2019. Patients with preoperative and postoperative magnetic resonance imaging with follow-up>one year were included. The following were noted: changes in subarachnoid cerebrospinal fluid, third ventricle diameter, bowing of the third ventricle floor, and postoperative flow void. Kaplan-Meier survival methods were used to assess ETV success and univariable and multivariable Cox proportional-hazards models were fitted to assess factors contributing to ETV success.

RESULTS

Fifty-eight subjects were included. Nineteen (32.8%) experienced failure within one year; individually, no single imaging parameter predicted success. However, all cases of failure had no identifiable flow void. Any postoperative radiological change was not consistently associated with decreased odds of failure. Obstructive hydrocephalus treated with ETV demonstrated significantly better ETV success than patients treated with nonobstructive hydrocephalus. Interobserver reliability was moderate for 2 of the radiological variables and substantial for 1 of the radiological variables.

CONCLUSIONS

Individually, none of the qualitative radiologic parameters measured in our study predicted ETV success. Absence of a flow void predicted ETV failure, but additional studies are needed to determine its true negative predictive value. Inability to clarify which specific parameter predicts success reflects the limited role of immediate postoperative imaging in influencing clinical management.

Triangular fossa of the third cerebral ventricle - an original 3D model and morphometric study

Introduction

The triangular recess (TR), also called triangular fossa or vulva cerebri, represents the anterior extension of the diencephalic ventricle, located between the anterior columns of the fornix and the anterior white commissure. Over time, this structure of the third cerebral ventricle generated many disputes. While some anatomists support its presence, others have opposite opinions, considering that it only becomes visible under certain conditions. The aim of the study is to demonstrate the tangible structure of the triangular recess. Secondly, the quantitative analysis allowed us to establish an anatomical morphometric standard, as well as the deviations from the standard.

Materials and methods

Our study is both a quantitative and a qualitative evaluation of the triangular fossa. We dissected 100 non-neurological adult brains, which were fixed in 10% formaldehyde solution for 10 weeks. The samples are part of the collection of the Institute of Anatomy, "Grigore T. Popa" University of Medicine and Pharmacy, Iasi. We highlighted the triangular fossa by performing dissections in two stages at the level of the roof of the III ventricle.

Results

The qualitative analysis is a re-evaluation of the classical data concerning the anatomy of the fossa triangularis. We proposed an original 3D model of the triangular recess in which we described a superficial part called vestibule and a deep part called pars profunda. We measured the sides of the communication between the two proposed segments, as well as the communication with the III ventricle. By applying the Heron's formula, we calculated the area of the two communications. Statistical evaluations have shown that these communications are higher than they are wide. In addition, there is a statistical difference between the surfaces of the two communications: 34.07 mm2 ± 7.01 vs. 271.43 mm2 ± 46.36 (p = 0.001).

Conclusion

The outcome of our study is both qualitative and quantitative. Firstly, we demonstrated the existence of the triangular fossa and we conceived a spatial division of this structure. Secondly, the measurements carried out establish an anatomo-morphometric norm of the triangular recess, which is useful in assessing the degree of hydrocephalus during the third endoscopic ventriculoscopy.

Endoscopic Third Ventriculostomy - A Review

BACKGROUND

Endoscopic third ventriculostomy (ETV) has become a proven modality for treating obstructive and selected cases of communicating hydrocephalus.

OBJECTIVE

This review aims to summarize the indications, preoperative workup, surgical technique, results, postoperative care, complications, advantages, and limitations of an ETV.

MATERIALS AND METHODS

A thorough review of PubMed and Google Scholar was performed. This review is based on the relevant articles and authors' experience.

RESULTS

ETV is indicated in obstructive hydrocephalus and selected cases of communicating hydrocephalus. Studying preoperative imaging is critical, and a detailed assessment of interthalamic adhesions, the thickness of floor, arteries or membranes below the third ventricle floor, and prepontine cistern width is essential. Blunt perforation in a thin floor, while bipolar cautery at low settings and water jet dissection are preferred in a thick floor. The appearance of stoma pulsations and intraoperative ventriculostomography reassure stoma and basal cistern patency. The intraoperative decision for shunt, external ventricular drainage, or Ommaya reservoir can be taken. Magnetic resonance ventriculography and cine phase-contrast magnetic resonance imaging can determine stoma patency. Good postoperative care with repeated cerebrospinal fluid drainage enhances outcomes in selected cases. Though the complications mostly occur in an early postoperative phase, delayed lethal ones may happen. Watching live surgeries, assisting expert surgeons, and practicing on cadavers and models can shorten the learning curve.

CONCLUSION

ETV is an excellent technique for managing obstructive and selected cases of communicating hydrocephalus. Good case selection, methodical technique, and proper training under experts are vital.

A Review of Common Endoscopic Intracranial Approaches

With the evolution of surgical techniques, endoscopy has emerged as a suitable alternative to many instances of more invasive methods. In this review article, we aim to discuss the endoscopic advancements, procedural details, indications, and outcomes of the most commonly practiced neuroendoscopic procedures. We have also summarized the uses, techniques, and challenges of neuroendoscopy in select neurosurgical pathologies.

Anterior third ventricular height and infundibulochiasmatic angle: two novel measurements to predict clinical success of endoscopic third ventriculostomy in the early postoperative period

OBJECTIVE

The authors sought to develop a set of parameters that reliably predict the clinical success of endoscopic third ventriculostomy (ETV) when assessed before and after the operation, and to establish a plan for MRI follow-up after this procedure.

METHODS

This retrospective study involved 77 patients who had undergone 78 ETV procedures for obstructive hydrocephalus between 2010 and 2015. Constructive interference in steady-state (CISS) MRI evaluations before and after ETV were reviewed, and 4 parameters were measured. Two well-known standard parameters, fronto-occipital horn ratio (FOHR) and third ventricular index (TVI), and 2 newly defined parameters, infundibulochiasmatic (IC) angle and anterior third ventricular height (TVH), were measured in this study. Associations between preoperative measurements of and postoperative changes in the 4 variables and the clinical success of ETV were analyzed.

RESULTS

Of the 78 ETV procedures, 70 (89.7%) were successful and 8 (10.3%) failed. On the preoperative MR images, the mean IC angle and anterior TVH were significantly larger in the successful procedures. On the 24-hour postoperative MR images of the successful procedures, the mean IC angle declined significantly from 114.2° to 94.6° (p < 0.05) and the mean anterior TVH declined significantly from 15 to 11.2 mm (p < 0.05). The mean percentage reduction of the IC angle was 17.1%, and that of the anterior TVH was 25.5% (both p < 0.05). On the 1-month MR images of the successful procedures, the mean IC angle declined significantly from 94.6° to 84.2° (p < 0.05) and the mean anterior TVH declined significantly from 11.2 to 9.3 mm (p < 0.05). The mean percentage reductions in IC angle (11%) and anterior TVH (16.9%) remained significant at this time point but were smaller than those observed at 24 hours. The 6-month and 1-year postoperative MR images of the successful group showed no significant changes in mean IC angle or mean anterior TVH. Regarding the unsuccessful procedures, there were no significant changes observed in IC angle or anterior TVH at any of the time points studied. Reduction of IC angle and reduction of anterior TVH on 24-hour postoperative MR images were significantly associated with successful ETV. However, no clinically significant association was found between FOHR, TVI, and ETV success.

CONCLUSIONS

Assessing the IC angle and anterior TVH on preoperative and 24-hour postoperative MR images is useful for predicting the clinical success of ETV. These 2 measurements could also be valuable as radiological follow-up parameters.

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.

Simplest radiological measurement related to clinical success in endoscopic third ventriculostomy

OBJECTIVE

Radiologic criteria for a successful endoscopic third ventriculostomy are not clearly defined and there is an ongoing need for determining simplest and strongest radiological criteria for this purpose. This paper aims to determine the easiest radiological parameter related to surgical outcome METHODS: Between January 2012 and December 2015 all patients receiving endoscopic third ventriculostomy with various indications were reviewed and 29 patients whose preoperative and early postoperative 3D-CISS images were available were studied. There were 13 males and 16 females, and there were 11 pediatric cases (mean age: 9.90±5.2; range: 2-18). The mean age of the entire population was 26.58±18.32 (range: 2-68 years). Measurements were performed using the ruler tool of a freely distributed medical imaging software. Simple ruler measurements of ventricular floor depression, lamina terminalis bowing, anterior commissure to tuber cinereum distance, mamillary body to lamina terminalis distance, third ventricular width, frontal horn width and occipital horn width were recorded and compared between successful and failed interventions.

RESULTS

Of the ventriculostomies, 22 (75.9%) were considered successful and 7 (24.1%) as failed at the last follow-up visit. Of the measurements performed, only those related to the third ventricle itself were significantly higher in the failed group. There were no association with lateral ventricular measurements.

CONCLUSION

Simple ruler measurements of the suggested distances significantly correlate with clinical success. After validating our results with higher number of patients, complex measurements and calculations to determine the link between clinical success and radiological success of ventriculostomy procedures may not be needed.

Neuroendoscopy in Kuwait: Evolution, Current Status, and Future Directions

An overview of the development of neuroendoscopy at the neurosurgery department, Ibn Sina Hospital in Kuwait, is presented with an outline of difficulties and obstacles faced by the field until it reached its current status. The factors and solutions that helped us overcome these problems are also elaborated on. After a modest beginning few years ago, endoscopic skull base procedures, intraventricular neuroendoscopy, and spinal endoscopy are regularly performed in the department. Although neuroendoscopy is not per se a neurosurgical subspecialty, it is an area that requires special training. Achieving an appropriate level of care necessitates these highly trained neurosurgeons to collaborate together and with other specialties to create teamsgeared towards offering such treatment options topatients. Importantly, a multitude of essential facilities should be available to make such a pattern of practice possible. In our experience, this was made possible through continued efforts that have finally paid off and gradually led to a complete shift of the face of neuroendoscopic practice in our department. Our future endeavors aim at further development of neuroendoscopy in the department to create a center of excellence.