Use of Recombinant Human Bone Morphogenetic Protein-2 at the C1-C2 Lateral Articulation without Posterior Structural Bone Graft in Posterior Atlantoaxial Fusion in Adult Patients

Early Outcomes of Bone Autografting in the Bilateral Atlantoaxial Joints Applied in Posterior Fusion Surgery

OBJECTIVE

Cable-dragged reduction and cantilever beam internal fixation can provide promising results in the treatment of atlantoaxial dislocation or instability. However, bilateral atlantoaxial joints bone autografting has not been conducted in this technique. We aim to evaluate the safety and effectiveness of bilateral atlantoaxial joints bone autografting in posterior cable-dragged reduction and cantilever-beam internal fixation.

METHODS

In this retrospective study, we included 14 patients with a minimum 24-month follow-up from December 2019 to September 2020. The granular bone harvested from the iliac crest was packed into the bilateral atlantoaxial joints of 14 patients in posterior cable-dragged reduction and cantilever-beam internal fixation. X-ray imaging and cervical computed tomography (CT) were performed during follow-up. The time required for bone fusion was recorded. The clinical outcomes were evaluated using the JOA scores, NDI, and VAS scores. Mann-Whitney U test, the chi-squared test, or the Fisher exact test were used to compare the two groups regarding patient characteristics, clinical outcomes, bone fusion rates, and cervical sagittal alignment.

RESULTS

The operations were successfully performed in all patients without any intraoperative complications. The mean operation time was (169.64 ± 20.91) minutes, and the intraoperative blood loss was (130.71 ± 33.62) mL. All patients received satisfactory reductions and firm bony fusion at the final follow-up. The fusion rates were 64.29% in the atlantoaxial joints and 21.43% in post bone graft area at 3 months postoperatively, and a significant difference was observed (p = 0.022). Besides, the cervical sagittal alignment in all patients was well maintained in the last follow-up compared to preoperatively. Importantly, a complete bony fusion in the atlantoaxial joints was observed in all patients. Moreover, the JOA, NDI, and VAS scores had improved significantly at the last follow-up.

CONCLUSION

Bone autografting of the bilateral atlantoaxial joints is a safe and effective technique to increase bone fusion rates, shorten bone fusion time, and reduce complication rates when the cable-dragged reduction and cantilever beam internal fixation approach is used. Therefore, it is a cost-effective surgical procedure for treating patients with atlantoaxial dislocation or instability.

Novelties for increased safety in cranio-vertebral surgery: a review

The cranio-vertebral junction (CVJ) was formerly considered a surgical "no man's land" due to its complex anatomical and biomechanical features. Surgical approaches and hardware instrumentation have had to be tailored in order to achieve successful outcomes. Nowadays, thanks to the ongoing development of new technologies and surgical techniques, CVJ surgery has come to be widely performed in many spine centers. Accordingly, there is a drive to explore novel solutions and technological nuances that make CVJ surgery safer, faster, and more precise. Improved outcome in CVJ surgery has been achieved thanks to increased safety allowing for reduction in complication rates. The Authors present the latest technological advancements in CVJ surgery in terms of imaging, biomaterials, navigation, robotics, customized implants, 3D-printed technology, video-assisted approaches and neuromonitoring.

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.