Comparative analysis of endoscopic third ventriculostomy trajectories in pediatric cases

Biomechanics of brain tissue damage caused by fiber endoscope penetration in third ventriculostomy surgery

Third ventriculostomy is the preferred treatment for obstructive hydrocephalus, but the biomechanics of brain tissue damage caused by fiber endoscopes remains unclear. In this study, brain tissue material parameters were tested based on the Ogden model to simulate needle puncture mechanics, and replicated the entire fiber endoscope advancement process during third ventriculostomy. It was found that a smaller diameter fiber endoscope, a perpendicular puncture angle, and a faster puncture speed would decrease the damage of brain tissue caused by the fiber endoscope. This study provides valuable insights for optimizing the instrumentation and surgical process of third ventriculostomy.

Developmental anatomy of the thalamus, perinatal lesions, and neurological development

The thalamic nuclei develop before a viable preterm age. GABAergic neuronal migration is especially active in the third trimester. Thalamic axons meet cortical axons during subplate activation and create the definitive cortical plate in the second and third trimesters. Default higher-order cortical driver connections to the thalamus are then replaced by the maturing sensory networks, in a process that is driven by first-order thalamic neurons. Surface electroencephalographic activity, generated first in the subplate and later in the cortical plate, gradually show oscillations based on the interaction of the cortex with thalamus, which is controlled by the thalamic reticular nucleus. In viable newborn infants, in addition to sensorimotor networks, the thalamus already contributes to visual, auditory, and pain processing, and to arousal and sleep. Isolated thalamic lesions may present as clinical seizures. In addition to asphyxia and stroke, infection and network injury are also common. Cranial ultrasound can be used to classify neonatal thalamic injuries based on functional parcelling of the mature thalamus. We provide ample illustration and a detailed description of the impact of neonatal focal thalamic injury on neurological development, and discuss the potential for neuroprotection based on thalamocortical plasticity.

Endoscopic third ventriculostomy complications: avoidance and management in a stepwise manner

Background

Various complications of endoscopic third ventriculostomy (ETV) have been described. One has to recognize these complications and learn how to avoid them.

Methods

We performed a literature review regarding the reported complications of ETV procedures discussed in a correlated manner with the surgical steps. Furthermore, we reviewed the technical notes described by experienced neuroendoscopists, including surgical indications, choice of the endoscopic entry point and trajectory, anatomic orientation, proper bleeding control and tight closure, to prevent and deal with such complications.

Results and conclusion

A lesson learned that comprehensive knowledge of ventricular anatomy with proper orientation by studying the preoperative images is mandatory and one should be aware of all complication types and rates.

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.

Operative planning aid for optimal endoscopic third ventriculostomy entry points in pediatric cases

OBJECT

Endoscopic third ventriculostomy (ETV) uses anatomical spaces of the ventricular system to reach the third ventricle floor and create an alternative pathway for cerebrospinal fluid flow. Optimal ETV trajectories have been previously proposed in the literature, designed to grant access to the third ventricle floor without a displacement of eloquent periventricular structures. However, in hydrocephalus, there is a significant variability to the configuration of the ventricular system, implying that the optimal ETV trajectory and cranial entry point needs to be planned on a case-by-case basis. In the current study, we created a mathematical model, which tailors the optimal ETV entry point to the individual case by incorporating the ventricle dimensions.

METHODS

We retrospectively reviewed the imaging of 30 consecutive pediatric patients with varying degrees of ventriculomegaly. Three dimensional radioanatomical models were created using preoperative MRI scans to simulate the optimal ETV trajectory and entry point for each case. The surface location of cranial entry points for individual ETV trajectories was recorded as Cartesian coordinates centered at Bregma. The distance from the Bregma in the coronal plane represented as "x", and the distance from the coronal suture in the sagittal plane represented as "y". The correlation between the ventricle dimensions and the x, y coordinates were tested using linear regression models.

RESULTS

The distance of the optimal ETV entry point from the Bregma in the coronal plane ("x") and from the coronal suture in the sagittal plane ("y") correlated well with the frontal horn ratio (FHR). The coordinates for x and y were fitted along the following linear equations: x = 85.8 FHR-13.3 (r ² = 0.84, p < 0.001) and y = -69.6 FHR + 16.7 (r ² = 0.83, p < 0.001).

CONCLUSION

The surface location of the optimal cranial ETV entry point correlates well with the ventricle size. We provide the first model that can be used as a surgical planning aid for a case specific ETV entry site with the incorporation of the ventricle size.