Technique and instrumentation
One always needs to remember: Minimally invasive ≠ minor surgery! It should only be undertaken in fully staffed and equipped neurosurgical operating rooms and by surgeons who are prepared to tackle its complications and also proceed to an open operation if necessary. Postoperative neuro-intensive care unit (ICU) is a must.
Principle of surgery:- to create an internal ﬁstula (passage) between the ventricular system and the area around base of the brain, called basal subarachnoid spaces so as to drain out the fluid trapped inside the ventricles into the subarachnoid system.
Surgeon should be able to appreciate the variations, abnormalities and distortions due to hydrocephalus/lesions and be able to guide the endoscope properly.
Endoscope gives a very high resolution but mono-ocular two dimensional (2-D) view, which is further 'tilted' (if 30` camera scope is used). So surgeon needs to very well get used to hand-eye coordination.
Surgical steps are simplified for the reader:
As against in a open surgery, in endoscopy, only a tiny hole is made into the skull, through which the endoscope is inserted into the ventricles of the brain, navigated from lateral ventricle into the smaller third ventricle, advanced to the appropriate location at the floor of the third ventricle, where the fistula or stoma is made with help of special instruments.
Comparison of a binocular, 3D cadaveric specimen (left) with monocular, 2D endoscopic intraoperative view of the floor of third ventricle. The star '*' indicates ideal site for fenestration.
Perforation is then made in the thinned floor of the third ventricle, allowing egress of cerebrospinal fluid (CSF) out of the blocked ventricular system and into the CSF space outside, but at the base of the brain (a normal CSF space).
A fistula or stoma (opening) is thus created and dilated to sufficient size, CSF flow is confirmed by observing to and fro flapping movements of the lips of the stoma.
Once the patency of the stoma is confirmed, scope is withdrawn and incision is closed.
Patient is usually observed in ICU overnight.
Over last 15 years, we have performed close to 100 ETV surgeries and our results are comparable to any top neurosurgical centers in the world. With experience, better case selection and small but important modifications in techniques, our results are even better.
Innovations in neurosurgery should ultimately lead to better quality of life in the patient and especially in case of children “level of reassurance and peace of mind” for their parents.