Inadvertent injury to eustachian tube leading to cerebrospinal fluid rhinorrhea is a known complication associated with drilling of Glasscock's triangle to expose the horizontal petrous internal carotid artery (ICA) for management of difficult tumors (especially malignant) or aneurysms at the cranial base. Contrary to the usual approach, we hypothesize that a ''medial-to-lateral'' approach to Glasscock's triangle drilling will minimize eustachian tube injury. Four formalin-fixed human cadaveric heads were dissected, and underwent appropriate morphometric analysis; yielding a total of eight datasets. The diameter of the horizontal petrous ICA exposed was 4.7 AE 0.9 mm (range, 3.8 to 5.6 mm).The mean distance from the medial carotid wall midpoint to the medialmost point on the eustachian tube was 6.35 AE 0.58 mm (range, 5.4 to 7.1 mm), yielding a ''safety zone'' for eustachian tube, ranging 0.2 to 1.9 mm lateral to the lateral carotid wall. With the medial-to-lateral approach, the eustachian tube remained preserved in all the specimens. The results of our study provide a practical, consistent, and safe method of maximizing horizontal petrous carotid artery exposure while minimizing the eustachian tube injury.
KEYWORDS: Petrous, carotid, eustachian tube, morphometricThe last two decades have seen tremendous evolution in skull base surgery. Even though skull base surgical techniques have evolved over time, the postoperative morbidity and mortality associated with them are a major area of concern for the surgeon considering quality of life as an important outcome parameter gauging the operative success.Surgical management of complex aneurysms, vascular lesions, and tumors encasing or invading the internal carotid artery (ICA) located at the skull base necessitates the exposure of the horizontal segment of the ICA located in the petrous bone. The most popular approach described to achieve the latter is the middle fossa approach or its variants. [1][2][3][4][5] The complex anatomy * These authors have contributed equally in this study.