Comparative Cadaveric Analysis for Surgical Corridor and Maneuverability: Far-Lateral Approach and Its Transcondylar Extension

Abstract

Objective: The necessity of partial occipital condyle (OC) resection for lesions in the ventral craniocervical junction is debatable. This study's purpose was to compare the surgical exposure of the classic far-lateral approach (FLA) and transcondylar FLA.

Methods: The classic FLA and transcondylar FLA were performed in 12 human cadaveric heads (24 sides). The surgical corridor of 3 levels (a: vagus nerve, b: from the midpoint of proximal ends of the vagus and hypoglossal nerves to the midpoint of the distal ends of each nerve, c: hypoglossal nerve) and the maneuverability (the area between neurovascular structures that limits instrumental maneuvers) were measured after each approach.

Results: The surgical corridors were significantly greater in transcondylar FLA than in classic FLA (a: 14.4 ± 3.4 mm vs. 17.1 ± 4.4 mm, P < 0.001; b: 8.6 ± 2.9 mm vs. 11.2 ± 4.1 mm, P < 0.001; c: 5.5 ± 2.2 mm vs. 7.7 ± 2.8 mm, P < 0.001). Transcondylar FLA also provided greater maneuverability than classic FLA (73.2 ± 23.9 mm 2 vs. 94.9 ± 32.2 mm 2 , P < 0.001). The increased length of the surgical corridor was greatest in a (a: 2.7 ± 2.3 mm, b: 2.6 ± 2.0 mm, c: 2.2 ± 1.4 mm). However, the rate of increase was greatest in c (a: 18.9 ± 16.4%, b: 30.4 ± 26.2%, c: 44.8 ± 27.2%). The area of increased maneuverability was 21.7 ± 20.3 mm 2 (31.1 ± 27.8%) after partial OC resection.

Conclusions: Transcondylar FLA can significantly increase surgical exposure compared with the classic FLA, although also increasing surgical complications. Therefore, the surgical approach should be individualized according to each lesion and patient. The results of our study may assist in surgical decision-making regarding the need for OC resection.