Introduction: The far lateral approach is commonly used in neurosurgical practice for the removal of lesions localized at the the cranio-vertebral junction (CCJ). There remains a lack of available endoscopic anatomical data. The anatomy, as seen through an endoscope, takes on a different perspective, and needs to be studied in detail in order to achieve familiarization with this different surgical perspective.
Methods: A conventional far lateral approach was performed on 6 preserved cadaveric heads (12 sides. On six sides a partial condylectomy was performed, and on six sides the approach was completed with resection of the jugular tubercle. In order to properly assess the exposure of specific major anatomic and neurovascular structures, as seen with the aid of the 3D endoscope, the intradural anatomy of the exposed CCJ was divided in eight compartments: three superior cranial compartments (anterior-medial, middle and posterior-lateral), three inferior cranial compartments (anterior-medial, middle and posterior-lateral), and two spinal compartments (anterior-medial and posterior-lateral).
Results: Our study provided a detailed description of the endoscopic anatomy of the cranio-vertebral junction. The anterior-medial compartments towards the midline were difficult to explore using the microscope alone and required the aid of the endoscope. The 3D endoscope provided general circumferential visualization of the anatomical structures, as well as visualization of the more lateral compartments. In addition, use of the 3D endoscope allowed for better perception of the depth of the field as compared to the conventional 2D endoscope. Our study also identified optimal and safe surgical corridors for insertion of the endoscopic probe. These corridors provide a safe entry point for proper visualization of deeper structures, however these corridors are too narrow to permit surgical maneuvers.
Conclusions: The use of a 3D endoscope allows for better visualization of the surgical compartments towards the midline and for better in-depth surgical exploration of each intradural compartment. Despite these promising results, the 3D probe is still too large and restricts surgical maneuvers. Further development of this tool is required to obtain complete data about its use through a far lateral approach.
Patient Care: This project highlights the advantages of using new 3D technology to enhance minimally invasive surgical approaches.
Learning Objectives: By the conclusion of this session, participants should be able to (1) describe the anatomy of the foramen magnum and cranio-vertebral junction and (2) discuss the use of the of the 3D endoscope with a far lateral approach.