Endoscopic third ventriculostomy (ETV) is a surgical technique within neurosurgery designed to manage fluid accumulation inside the brain. The procedure aims to re-establish physiological cerebrospinal fluid (CSF) circulation without inserting foreign hardware. Under endoscopic visualization, the neurosurgeon punctures the thin membrane at the base of the brain's third ventricle, allowing trapped CSF to flow directly into the subarachnoid cisterns for natural absorption.

The patient is placed under general anaesthesia in a supine position with the head slightly flexed. A standard right frontal precoronal burr hole is created approximately 3 centimetres off the midline and 1 to 2 centimetres anterior to the coronal suture. The dura mater is incised, and a rigid or flexible neuroendoscope with a irrigation channel and working instrument port is advanced into the frontal horn of the right lateral ventricle. The neurosurgeon identifies anatomical landmarks: the foramina of Monro, thalamostriate vein, septal vein, and choroid plexus. The endoscope is carefully guided through the foramen of Monro into the third ventricle. The surgeon inspects the floor of the third ventricle to identify the optic chiasm anteriorly, the mamillary bodies posteriorly, and the translucent tuber cinereum in the center. Using blunt endoscopic instruments, a micro-balloon catheter, or sharp neuro-forceps, the tuber cinereum is micro-perforated. The stoma is gently dilated with a balloon catheter to achieve an effective diameter of 4 to 6 millimetres. The underlying Liliequist membrane is inspected and widely opened to ensure unhindered CSF flow into the interpeduncular subarachnoid space. Pulsatile movement of the ventricular floor and CSF flow through the stoma are confirmed visually. Continuous warm lactated Ringer solution irrigation maintains ventricular inflation and visual clarity throughout. Endoscopic hardware is withdrawn, the ventriculostomy tract is secured, and the scalp incision is closed in layers.

Endoscopic third ventriculostomy provides distinct physiological and clinical advantages for appropriately selected candidates:

• Hardware independence: Unlike ventricular shunts, ETV does not require permanent synthetic tubing or valves, eliminating hardware-related risks such as mechanical valve failure, catheter disconnection, or skin breakdown (Hydrocephalus Clinical Research Network [HCRN], 2014).
• Lower long-term infection risk: While shunts harbor lifelong risks of bacterial colonization, ETV infection risks are limited strictly to the immediate perioperative window (AANS/CNS Guidelines, 2020).
• Physiological CSF dynamics: ETV restores near-normal pulsatile internal CSF circulation, avoiding problems of over-drainage or under-drainage commonly observed with mechanical pressure valves.
• Fewer repeat procedures over a lifetime: Successful ETV procedures exhibit high long-term durability; once patency is established beyond the first six post-operative months, delayed failure rates drop substantially compared to baseline shunt failure rates (Kulkarni et al., 2011).
• Single-stage biopsy option: In cases where obstructive hydrocephalus is caused by an intraventricular or pineal region mass, ETV allows simultaneous endoscopic biopsy of the lesion through the same surgical corridor.

Immediate postoperative recovery takes place in an intensive care setting for 24 hours to monitor neurological status, vital signs, and surgical site integrity. Patients typically transition to a surgical ward on day 2 and are discharged home within 48 to 72 hours if clinically stable. Minor incisional discomfort and mild transient headache are managed with standard analgesics. Most adult patients return to routine light daily activities within 2 weeks post-procedure. Complete return to unrestricted physical exertion, strenuous work, or contact sports typically occurs by 4 to 6 weeks, following clinical clearance and follow-up MRI verification of stoma patency.

Endoscopic third ventriculostomy is primarily indicated for structural obstructive hydrocephalus. Specific conditions treated include:

• Aqueductal stenosis (congenital or acquired narrowing of the aqueduct of Sylvius)
• Posterior fossa tumours causing ventricular compression (e.g., medulloblastoma, cerebellar astrocytoma, ependymoma)
• Pineal region masses and tectal gliomas
• Chiari malformation type I or type II with secondary obstructive hydrocephalus
• Dandy-Walker malformation with secondary aqueductal obstruction
• Ventriculoperitoneal shunt failure or infection (conversion from shunt dependency to ETV)
• Arachnoid cysts of the posterior fossa or quadrigeminal cistern causing flow obstruction

Preoperative preparation for ETV requires comprehensive diagnostic imaging. A high-resolution magnetic resonance imaging (MRI) study of the brain—specifically including thin-slice sagittal T2-weighted or constructive interference in steady state (CISS/3D-DRIVE) sequences—is mandatory to evaluate third ventricle anatomy, thickness of the tuber cinereum, floor baseline distance to the basilar artery, and subarachnoid space patency. Standard laboratory evaluations include complete blood counts, basic metabolic panels, and coagulation profiles (prothrombin time, activated partial thromboplastin time, international normalized ratio). Antiplatelet agents, anticoagulants, and specific non-steroidal anti-inflammatory drugs must be discontinued 5 to 10 days prior to surgery under specialist guidance. Patients must observe strict fasting guidelines (nothing by mouth) for at least 6 to 8 hours prior to general anaesthesia administration.

Surgical complications associated with ETV are categorized by severity. Minor or transient risks include surgical site pain, localized scalp swelling, postoperative low-grade fever, and self-limiting headache. Moderate risks include transient memory disturbance or confusion (secondary to traction on the fornix at the foramen of Monro), transient cranial nerve III (oculomotor) palsy causing temporary double vision, and post-procedural CSF leak from the wound site (1% to 3%). Major or critical complications include intraventricular haemorrhage from vascular injury (less than 1%), major arterial injury to the basilar artery or its branches (0.2% to 0.5%), direct injury to the hypothalamic nuclei or fornix causing permanent neuro-endocrine or short-term memory impairment, deep cerebral infection (meningitis or ventriculitis, 1% to 2%), acute postoperative stoma closure leading to rapid re-accumulation of intracranial pressure, and severe neurological deficit or mortality (less than 1% in major referral centers).

The clinical care pathway for endoscopic third ventriculostomy begins with comprehensive neuroimaging, including high-resolution magnetic resonance imaging (MRI) with CSF flow study dynamics. Preoperative evaluation includes neurological scoring, blood coagulation panels, and anaesthetic assessment. On the day of surgery, general anaesthesia is administered, followed by a small frontal craniostomy. Using a rigid or flexible neuroendoscope, the surgeon accesses the third ventricle and creates an anatomical perforation in the tuber cinereum. Postoperatively, patients spend 24 to 48 hours in an intensive care or step-down unit for continuous intracranial monitoring. Long-term follow-up involves baseline MRI scans at 3 months and periodic clinical evaluations to confirm persistent fenestration patency and hydrocephalus resolution.