Three-dimensional endoscope-assisted surgical approach to the foramen magnum and craniovertebral junction: minimizing bone resection with the aid of the endoscope.

Overview

OBJECTIVE: To evaluate objectively the anatomic areas of the cranial base exposed by a three-dimensional (3D) endoscope-assisted far lateral approach. METHODS: A series of far lateral approaches with only condyle resection, with only jugular tubercle resection, with both partial condyle and total jugular tubercle resection, and without occipital condyle and jugular tubercle resection were performed on 10 cadaveric heads (20 sides). To assess properly the exposure of major anatomic and neurovascular structures, the intradural anatomy of the exposed craniocervical junction was divided into 8 compartments, including 3 superior cranial compartments, 3 inferior cranial compartments, and 2 spinal compartments. RESULTS: The anteromedial compartments toward the midline were difficult to explore using the microscope and required the aid of the endoscope. The 3D endoscope provided general circumferential visualization of the anatomic structures, even without resection of the jugular tubercle, and afforded good visualization of the more lateral compartments. Safe and optimal surgical corridors for insertion of the endoscope were also identified. CONCLUSIONS: Use of a 3D endoscope allows for minimal resection of the condyle and jugular tubercle, better visualization of the surgical compartments toward the midline, and better in-depth surgical exploration of each intradural compartment. However, the 3D probe is still too large and restricts surgical maneuverability.