Technical refinement of semispinalis cervicis–preserving occipitocervical fixation for rheumatoid arthritis/basilar invagination

Background: Conventional occipitocervical (O–C) fixation for rheumatoid arthritis (RA)-associated basilar invagination (BI) may require extensive dissection and detachment of the posterior cervical extensor musculature. As this included the semispinalis cervicis (SSC), it may result in significant postoperative axial neck pain. Here, we describe a technical refinement of O–C fixation that preserves the SSC distal to its C2 attachment. Case Description: A 48-year-old female presented with RA-associated BI and C4/5 spondylolisthesis. A posterior O–C to C5 fixation utilized an intermuscular dissection plane between the SSC and semispinalis capitis. Utilizing 3-D navigation, this allowed for exposure of the subaxial screw entry points while preserving the SSC caudal to C2, and ensured accurate screw placement. Postoperatively, at 8 postoperative months, her axial neck pain improved (i.e., visual analog scale 6–1), bridging bone indicated solid fusion, while the magnetic resonance confirmed indirect adequate neural decompression without SSC atrophy. Conclusion: This SSC-preserving O–C-C5 fixation technique achieved successful fusion in this case while avoiding postoperative axial neck pain and SSC atrophy.