The telovelar approach reshaped: a new perspective from inside the fourth ventricle

Area of Science:

• Neurosurgery
• Neuroanatomy
• Surgical Endoscopy

Background:

• Trans-cerebellomedullary fissure (trans-CMF) approaches are key for fourth ventricle surgery.
• Traditional approaches rely on cadaveric studies of normal ventricles.
• Clinical practice often involves dilated and distorted fourth ventricles due to tumors.

Purpose of the Study:

• To reassess traditional schematic representations of trans-CMF approaches using in vivo endoscopic views.
• To provide neurosurgeons with a realistic in vivo perspective of the ventricular roof in different ventricular sizes.
• To refine understanding of the telovelar approach in dilated fourth ventricles.

Main Methods:

• Panoramic endoscopic views of the inner roof of twelve fourth ventricles (normal and hydrocephalic) were analyzed.
• Anatomical landmarks were identified.
• Schematic cutlines of telovelar procedures were redesigned based on Matsushima's diagrams.

Main Results:

• Realistic models of internal roof dissections were created.
• Safest and least safe tracks of the telovelar approach were identified.
• Anatomical representation of the internal surface of dilated fourth ventricles was achieved.

Conclusions:

• The study provides a more realistic anatomical model of the internal surface of dilated fourth ventricles.
• This model aligns better with clinical realities of tumor-deformed ventricles.
• Replicating dissections on internal roof images enhances anatomical understanding of the trans-CMF approach.