Novel freehand frontal ventriculostomy in the supraorbital keyhole approach: technical note

The narrow surgical passage provided by the supraorbital keyhole craniotomy restricts the instrument's maneuverability and presents a number of technical challenges. Inadequate brain relaxation may eventually result in unavoidable brain retraction and neurological impairments. The article aims to provide a novel intraoperative ventriculostomy to assist in overcoming the barrier of a narrow surgical corridor and assess its feasibility and safety compared to other techniques.

The craniometric point was planned on one normal computed tomography (CT) brain. The coordinates were verified on 43 magnetic resonance imaging (MRI) brain images uploaded on the neuronavigation system (StealthStation S8 version 1.0; Medtronic, Louisville, USA). The ventriculostomy point was 3 cm superior to glabella, 2 cm lateral to midline, 6 cm deep to the brain surface in the perpendicular direction, and parallel to the floor of the anterior cranial fossa. Subsequently, the abovementioned radiologically calculated ventriculostomy trajectory was confirmed on 32 consecutive patients (without neuronavigation) of suprasellar mass undergoing supraorbital craniotomy between February 2022 and April 2023. The technical issues, feasibility, and outcomes were assessed.

Out of 32 patients, in 29 patients, ventricular hit was attained in a single attempt, and the rest 3 patients needed two attempts. The intraoperative ventricular hit rate was 100% with 90.6% success in a single attempt. No ventriculostomy-related complications occurred. Compared to ELD (external lumbar drainage), performing an intraoperative ventriculostomy had no discernible difference in the perception of the brain retraction force. Intraoperative ventriculostomy fully eliminated the low back pain or radiculopathy that patients with ELD rarely have even after drain removal.

The novel intraoperative frontal ventriculostomy is a safe trajectory and is a valid alternative to Menovsky's ventriculostomy or external lumbar drainage. The authors recommend this technique be generally utilized in supraorbital keyhole approaches to optimize brain relaxation and minimize secondary adverse events.