Revisit to Endolymphatic Duct Identification Using Middle Cranial Fossa Dural Plate: A Novel Technique

Surgical treatments for Ménière's disease differ in efficacy. Endolymphatic duct blockage (EDB) is favored for its minimal risk and ability to preserve hearing. One of the main challenges in the technique is the difficulty in accurately identifying the endolymphatic duct (ED). The aim of the study is to see the feasibility of identifying the ED opening using a middle cranial fossa (MCF) dural plate as a reference point in a wet temporal bone and to measure the angle between the ED opening and the MCF dural plate which in the future can simplify the procedure of ED blockage.

This prospective observational study, conducted from February to April 2024 at R L Jalappa Hospital, involved dissecting 20 wet temporal bones. A complete cortical mastoidectomy exposed the MCF dural plate, semicircular canals, sigmoid sinus, and sinodural angle. Using Donaldson line ES, through blind controlled drilling the operculum of the vestibular aqueduct was identified. The angle between the ED opening and the MCF dural plate was measured using GNU Image Manipulation Program (GIMP) software (Free Software Foundation Ltd., Boston, MA, USA). A tangential line from the MCF dural plate to the ED opening was drawn using the same software and the line was named the "GauthamaPrasads" (GP) line.

The study documented angles between the ED opening and the MCF dural plate, which ranged from 36.00° to 45.99° (mean angles from 20 temporal bones provided).

The angle of 36.00° to 45.99° between the MCF dural plate and ED was consistently observed, thus proving that the MCF dural plate is a reliable anatomical landmark for surgeons for identification of ED. Accurate identification of the ED was feasible using this new anatomical landmark. These findings provide valuable anatomical insights that can aid in more efficient and accurate surgical interventions involving the ED.