O-arm-assisted endoscopic endonasal decompression for medullary compression caused by a clival osteophyte: illustrative case.

BACKGROUND

The craniovertebral junction contains critical structures such as the medulla oblongata, upper cervical spinal cord, and vertebral arteries; therefore, selecting the surgical approach is particularly important given its anatomical complexity. Various anterior approaches have been proposed for this purpose. However, in recent years, endoscopic endonasal decompression has increasingly replaced the traditional transoral approach for the treatment of upper anterior lesions.

OBSERVATIONS: The authors encountered a case of ventral medullary compression caused by an inferior clival osteophyte that progressively enlarged after C1-2 fixation. The endoscopic endonasal approach (EEA), which provides the shortest and most direct route to the lesion, was selected for this study. Intraoperative use of the O-arm enabled precise real-time assessment of the extent of bone removal, thereby enabling complete decompression. Mechanical loading following C1-2 fixation is considered a possible contributing factor to osteophyte enlargement.

LESSONS: Although neuronavigation is commonly used in the EEA, its reliance on preoperative imaging limits its ability to accurately assess decompression. The O-arm, which provides real-time intraoperative imaging, has proven extremely useful in overcoming this limitation. https://thejns.org/doi/10.3171/CASE251039.