Clinical and Radiographic Outcomes of C1 Laminectomy Without Fusion for the Retro-Odontoid Pseudotumor in Non-Rheumatoid Arthritis
Kohei Kuroshima, Takashi Yurube, Yoshiki Takeoka, Yutaro Kanda, Naotoshi Kumagai, Yoshiaki Hiranaka, Koki Kawaguchi, Norihiko Takegami, Koji Akeda, Soya Kawabata, Nobuyuki Fujita, Ryosuke Kuroda, Kenichiro KakutaniStudy Design:
Retrospective case series.
Objective:
To clarify clinical and radiographic outcomes of C1 laminectomy without fusion for the retro-odontoid pseudotumor (ROP) without rheumatoid arthritis (RA), and explore preoperative factors potentially associated with postoperative ROP size changes.
Summary of Background Data:
Upper cervical fusion is widely performed for ROP, as atlantoaxial instability is considered a major pathogenic mechanism. Nevertheless, several studies have reported favorable outcomes after C1 laminectomy alone. However, the postoperative change in ROP size following C1 laminectomy remains poorly understood.
Materials and Methods:
Twenty-one consecutive patients with ROP without RA who underwent C1 laminectomy and completed a minimum two-year follow-up were retrospectively reviewed. Clinical outcomes were assessed using the total 17-point Japanese Orthopaedic Association (JOA) score. Radiographic parameters, including the atlantodental interval, cervical alignment, and ROP size on magnetic resonance imaging, were evaluated preoperatively and at the final follow-up. Unadjusted univariate linear regression analysis was performed to explore associations between preoperative factors and postoperative changes in ROP size.
Results:
The mean follow-up duration was 48.0±21.6 months. The JOA score improved significantly from 8.7±2.5 to 11.3±3.4 points (
Conclusion:
C1 laminectomy without fusion led to significant neurological improvement in patients with ROP without RA. Although overall ROP size did not change significantly, a larger preoperative ROM of the C1–C2 angle was associated with postoperative ROP enlargement, an exploratory finding that may inform postoperative surveillance and surgical decision-making but requires validation in larger prospective cohorts.