Feasibility of Occipital Condyle Screw Fixation for Craniocervical Instability: Integrating Morphometric Evidence,...

Instability of the craniocervical junction is a potentially life-threatening condition requiring surgical stabilization. Traditional occipital plate fixation carries risks of construct loosening and intracranial complications due to variable skull thickness, particularly after posterior fossa decompression where plate fixation is challenging. Occipital condyle screws (OCS) provide direct fixation into the occipital condyles (OCs). However, comprehensive outcome data remains sparse. This systematic review and meta-analysis evaluated anatomical parameters, technical aspects, and surgical outcomes of OCS fixation in craniocervical stabilization. Following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines, PubMed/MEDLINE, Embase, and Scopus were searched for studies reporting techniques and outcomes of occipitocervical fixation using OCS. Two reviewers independently extracted data, and study quality was assessed using the Newcastle-Ottawa Scale, when possible. Random-effects meta-analysis was performed. The primary endpoint was to characterize the technical aspects of craniocervical fixation using OCS and to ascertain its overall feasibility, defined by morphometric suitability, technical success rates, and complication rates. Thirty studies met inclusion: 12 cadaveric (618 specimens), 10 imaging (1,604 participants), and 8 surgical (284 patients). Morphometry consistently showed larger OC in male populations. Bicortical screw placement achieved 100% technical success. Standard 3.5-mm screws (18-24 mm) were commonly used. Recommended trajectories varied (sagittal with 18°-28° angulation; axial with 22°-37° angulation). No major symptomatic vascular or permanent neurological complications occurred. Meta-analytic data revealed significant differences in morphometric measurements of the OC and differences in the OCS length and angulation parameters. OCS fixation appears to be an anatomically feasible and technically promising fixation strategy in selected patients when anatomy and technique are carefully evaluated. Population-specific morphometric variability mandates individualized preoperative assessment. Future comparative studies should define long-term outcomes, fusion rates, and optimize region-specific surgical parameters.