Combined C1–2 transarticular screw fixation and C1 laminoplasty with interlaminar bone transplant for retro-odontoid pseudotumor: illustrative case

BACKGROUND: The surgical treatment for retro-odontoid pseudotumor (ROP) remains controversial. Posterior C1 laminectomy without fixation occasionally leads to postoperative enlargement of ROP. Because its pathogenesis is associated with atlantoaxial instability, atlantoaxial fixation with C1 laminectomy is commonly performed. Atlantoaxial fixation usually includes transarticular fixation and screw-rod fixation. However, these methods have some issues. That is, in transarticular fixation with C1 laminectomy, the bone grafting area is challenging to obtain. In screw-rod fixation with C1 laminectomy, extensive bleeding occurs at times if the lateral atlantoaxial joint is exposed to the transplant bone grafts. OBSERVATIONS: Herein, the authors report a case of ROP treated with combined C1–2 transarticular screw fixation and C1 laminoplasty with interlaminar bone transplant, which can help achieve adequate spinal cord decompression and can simultaneously secure the bone grafting area between the laminae. In addition, the volume of intraoperative blood loss decreased. Postoperative magnetic resonance imaging showed sufficient decompression of the spinal cord at the C1 level, and computed tomography performed after 6 months revealed bone union between the C1 and C2 laminae. LESSONS: Combined C1–2 transarticular screw fixation and C1 laminoplasty with interlaminar bone transplant is a useful method for ROP.