A light on the dark side: In vivo endoscopic anatomy of the posterior third ventricle and its variations in hydrocephalus

Objective: Despite the technological advancements of neurosurgery, the posterior part of the third ventricle has always been the "dark side"of the ventricle. However, flexible endoscopy offers the opportunity for a direct, in vivo inspection and detailed description of the posterior third ventricle in physiological and pathological conditions. The purposes of this study were to describe the posterior wall of the third ventricle, detailing its normal anatomy and surgical landmarks, and to assess the effect of chronic hydrocephalus on the anatomy of this hidden region. Methods: The authors reviewed the video recordings of 59 in vivo endoscopic explorations of the posterior third ventricle to describe every identifiable anatomical landmark. Patients were divided into 2 groups based on the absence or presence of a chronic dilation of the third ventricle. The first group provided the basis for the description of normal anatomy. Results: The following anatomical structures were identified in all cases: adytum of the cerebral aqueduct, posterior commissure, pineal recess, habenular commissure, and suprapineal recess. Comparing the 2 groups of patients, the authors were able to detect significant variations in the shape of the adytum of the cerebral aqueduct and in the thickness of the habenular and posterior commissures. Exploration with sodium fluorescein excluded the presence of any fluorescent area in the posterior third ventricle, other than the subependymal vascular network. Conclusions: The use of a flexible scope allows the complete inspection of the posterior third ventricle. The anatomical variations caused by chronic hydrocephalus might be clinically relevant, in light of the commissure functions

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

A restricted neuroendoscopic approach for pathological diagnosis ofintraventricular and paraventricular tumours.

Abstract BACKGROUND: There is increasing interest in the use of neuroendoscopic techniques in neuro-oncology. We report our experience of endoscopic biopsy in patients harbouring intraventricular and paraventricular brain tumours in order to define criteria for the use of this technique. METHODS: We identified 23 patients (aged 7-78 years) who underwent endoscopic biopsy for intraventricular or paraventricular lesions considered not suitable for surgical removal and too risky for a stereotactical approach. All of the biopsies were obtained with a flexible endoscope using a free-hand technique. FINDINGS: In 16 patients specimens were adequate and led to a diagnosis; in three patients they were informative but not completely diagnostic; a pathological diagnosis was unavailable in four patients. In 13 patients with a lesion causing an obstruction of the aqueduct, a third ventriculostomy was performed during the same procedure; in one patient with a lesion occluding the Monro foramen, a septostomy was done, while in another case multiple cystostomies were required. No specific complications were observed, either clinically or radiologically, in particular no major bleeding occurred. CONCLUSIONS: In our experience, endoscopic biopsy could provide a pathological diagnosis in 19 of 23 patients. Endoscopic biopsy sampling sufficient tissue should be considered as the first choice in selected lesions that are otherwise difficult to approach

Neuroendoscopic aspiration of hematocephalus totalis: technical note

Abstract OBJECTIVE AND IMPORTANCE: Massive intraventricular hemorrhage requires aggressive and rapid management to decrease intracranial hypertension. The amount of intraventricular blood is a strong prognostic predictor, and its fast removal is a priority. Neuroendoscopy may offer some advantages over more traditional surgical approaches. We describe here the technical details and clinical outcomes of the neuroendoscopic management of massive tetraventricular hemorrhage in 25 consecutive patients, highlighting the potential pitfalls and the advantages of the technique. CLINICAL PRESENTATION: Twenty-five patients, aged 7 to 80 years, presenting with massive ventricular hemorrhage were admitted between January 1996 and May 2004 to our neurosurgery unit after an emergency computed tomographic scan. Severity of ventricular hemorrhage was graded according to the Graeb scale; the mean Graeb score was 9.8 +/- 2.9. Hemorrhages were secondary to vascular malformation in 12 cases. INTERVENTION: Endoscopy was performed on the first day in 17 cases, with a delay of 1 to 5 days in the remaining 8 cases. A flexible endoscope with "free-hand" technique was always preferred. The ventricular cleaning proceeded in three phases: lateral ventricle, third ventricle, and then aqueduct and fourth ventricle. In selected patients, a catheter, both for intracranial pressure monitoring and for drainage, was positioned. The procedure was successfully completed in all cases. There was no surgery-related mortality. The mean length of intensive care unit stay after the operation was 18 +/- 12 days. Short-term mortality (1 mo) was 12%, whereas long-term (> 6 mo) mortality was 24%. Complete recovery (Glasgow Outcome Scale score, 5) was achieved in 40% of cases. A ventriculoperitoneal shunt was necessary in 12% of patients. CONCLUSION: Intraventricular hemorrhage, analogously to other ventricular diseases, can be treated successfully with flexible endoscopes. Obviously, the limitation of this study lies in its observational nature; however, the encouraging results reported here should prompt a randomized study to evaluate the effectiveness and efficiency of the endoscopic approach in comparison to the more established semiconservative management offered by external derivation with fibrinolytic agents

Failure of endoscopic third ventriculostomy in the treatment of idiopathic normal pressure hydrocephalus

Even though the main indication for neuroendoscopic management of normal pressure hydrocephalus (NPH) is the presence of an aqueductal block, recent reports suggest the possible efficacy of endoscopic third ventriculostomy (ETVS) in idiopathic NPH. We present 14 cases with apparently idiopathic NPH treated by ETVS, and report on the low rate of success (21 %). A closer analysis of the successful cases reveals possible elements which may explain the good outcome, and should be taken into consideration when defining the best strategy to address NPH

Endoscopic opening of the foramen of Magendie using transaqueductal navigation for membrane obstruction of the fourth ventricle outlets - Technical note

A membrane obstruction of the foramina of Magendie and Luschka is an uncommon origin of hydrocephalus characterized by unusual clinical symptoms of rhomboid fossa hypertension. Various surgical approaches have been proposed to alleviate this obstruction, including opening the obstructed foramen of Magendie using suboccipital craniectomy, shunting procedures, and more recently, endoscopic third ventriculostomy (ETV). In some cases, however, reshaping of the posterior fossa due to the collapse of the prepontine cistern could make ETV difficult for the surgeon and dangerous to the patient. In these cases, endoscopic opening of the foramen of Magendie by transaqueductal navigation of the fourth ventricle is a suitable and feasible therapeutic option

Neuroendoscopic aspiration of tumors in the posterior third ventricle and aqueduct lumen: a technical update

Background: Small soft ventricular tumors are good candidates for complete removal by a purely endoscopic technique. This approach is particularly interesting for lesions located in the posterior third ventricle and aqueductal lumen. Methods: We present our method of endoscospic aspiration through direct contact between the tumor and the working channel of a flexible scope. Results: Aspiration without the intermediate use of cannulas is safe and has proved to be effective in the apparently total or partial removal of three soft tumors of different pathologies located in the third ventricle or aqueductal lumen. In one case, a second neuroendoscopy a few months later to repeat endoscopic third ventriculostomy (ETV) offered a unique opportunity to observe the absence of the tumor and the restored anatomy. Conclusions: Neuroendoscopy provides a safe, effective way to radically resect small soft tumors in these troublesome locations and can be a valuable alternative to microsurger