Rigid versus flexible neuroendoscopy: a systematic review and meta-analysis of endoscopic third ventriculostomy for the management of pediatric hydrocephalus

Fetal Endoscopic Third Ventriculostomy Is Technically Feasible in Prenatally Induced Hydrocephalus Ovine Model

BACKGROUND

Congenital obstructive hydrocephalus generates progressive irreversible fetal brain damage by ventricular enlargement and incremental brain tissue compression that leads to maldevelopment and poor clinical outcomes. Intrauterine treatments such as ventriculo-amniotic shunting have been unsuccessfully tried in the eighties.

OBJECTIVE

To assess if prenatal endoscopic third ventriculostomy (ETV) is feasible in a large animal model and optimize this technique for ventricular decompression and potential arrest of fetal brain damage in fetal lambs.

METHODS

We generated hydrocephalus in 50 fetal lambs by injecting a polymeric agent into the cisterna magna at midgestation (E85). Subsequently, 3 weeks later (E105), fetal ETV was performed using a small rigid fetoscope. The endoscopy entry point was located anterior to the coronal suture, 7 mm from the midline.

RESULTS

We obtained clear visualization of the enlarged lateral ventricles by endoscopy in the hydrocephalic fetal lambs. The floor of the third ventricle was bluntly perforated and passed with the scope for a successful ETV. Total success was achieved in 32/50 cases (64%). Causes of failure were blurred vision or third ventricle obliteration by BioGlue in 10/50 (20%) cases, anatomic misdirection of the endoscope in 5 (10%) cases, 2 cases of very narrow foramen of Monro, and 1 case of choroid plexus bleeding. If we exclude the cases artificially blocked by the polymer, we had a successful performance of prenatal-ETV in 80% (32/40) of hydrocephalic fetuses.

CONCLUSION

Despite the inherent difficulties arising from ovine brain anatomy, this study shows that innovative fetal ETV is technically feasible in hydrocephalic fetal lambs.

Late-onset obstructive hydrocephalus associated with occipital encephalocele with large skull defect successfully treated by endoscopic third ventriculostomy

BACKGROUND

Hydrocephalus is one of the most common presentations of occipital encephaloceles and usually develops within the first year of life. This case report presents a rare case of late-onset obstructive hydrocephalus associated with occipital encephalocele with an extraordinarily large occipital skull defect.

CASE REPORT

At birth, a newborn girl presented with an absence of a vast amount of occipital cranium and skin and was diagnosed with occipital hydroencephalomeningocele. Under meticulous sterile management, the affected area was successfully epithelialized, and the patient was discharged without infectious complication. Despite an obstructed cerebral aqueduct, she grew without any signs of hydrocephalus until the age of 7 years. Her gait gradually worsened, and imaging tests at the age of 8 years revealed markedly enlarged lateral and third ventricles but not the fourth ventricle. Endoscopic third ventriculostomy successfully relieved her symptoms with improvement of hydrocephalus.

CONCLUSION

This is the first case of late-onset obstructive hydrocephalus associated with an occipital encephalocele characterized by large-scale cranial bony defects. Although further investigation is required to elucidate the mechanism of hydrocephalus, this rare phenomenon should be noted during neurological and radiological follow-up.

Evaluation of the precision of navigation-assisted endoscopy according to the navigation tool setup and the type of endoscopes

OBJECT

Preoperative image-based neuronavigation-assisted endoscopy during intracranial procedures is gaining great interest. This study aimed to analyze the precision of navigation-assisted endoscopy according to the navigation setup, the type of optic and its working angulation.

METHODS

A custom-made box with four screws was referenced. The navigation-assisted endoscope was aligned on the screws (targets). The precision on the navigation screen was defined as the virtual distance-to-target between the tip of the endoscope and the center of the screws. Three modifiers were assessed: (1) the distance D between the box and the reference array (CLOSE 13 cm - MIDDLE 30 cm - FAR 53 cm), (2) the distance between the tip of the endoscope and the navigation array on the endoscope (close 5 cm - middle 10 cm - far 20 cm), (3) the working angulation of the endoscope (0°-endoscope and 30°-endoscope angled at 90° and 45° with the box).

RESULTS

The median precision was 1.3 mm (Q1: 1.1; Q3: 1.7) with the best setting CLOSE/close. The best setting in surgical condition (CLOSE/far) showed a distance-to-target of 2.3 mm (Q1: 1.9; Q3: 2.5). The distance D was correlated to the precision (Spearman rho = 0.82), but not the distance d (Spearman rho = 0.04). The type of optic and its angulation with the box were also correlated to the precision (Spearman rho =  - 0.37). The best setting was the use of a 30°-endoscope angled at 45° (1.4 mm (Q1: 1.0; Q3: 1.9)).

CONCLUSION

Navigated-assisted endoscopy is feasible and offers a good precision. The navigation setup should be optimized, reducing the risk of inadvertent perifocal damage.