Study design A retrospective study was conducted to evaluate anterior plate fixation of unstable atlas fractures using a transoral approach. Objective To further investigate the safety and efficacy of this surgical technique, as there is currently a paucity of available data. Summary of background data While most atlas fractures can be managed by external immobilization with favorable results, surgery is usually preferable in highly unstable cases. Surgical stabilization is most commonly achieved using a posterior approach with fixation of C1-C2 or C0-C2, but these techniques usually result in loss of joint function and cannot fully stabilize anterior arch fractures of the atlas. Although a transoral approach circumvents these issues, only nine cases were described in the literature to our knowledge. Methods Twenty patients with unstable atlas fractures were treated with this technique during a 6-year period. Screw and plate placement, bone fusion, and integrity of spinal cord and vertebral arteries were assessed via intraoperative and follow-up imaging. Neurologic function, range of motion, strength, pain levels, and signs of infection were assessed clinically upon follow-up.Results There were no incidents of screw loosening or breakage, plate displacement, spinal cord injury, or vertebral artery injury. A total of 20 plates were placed and all 40 screws were inserted into the atlas lateral masses. CT scans demonstrated that two screws were placed too close to the vertebral artery canal, but without clinical consequences. Imaging demonstrated that bone fusion was achieved in all cases by 6 months postoperatively, without intervertebral instability. No plate-related complications were observed in any patients during the follow-up period. Conclusions C1 anterior plate fixation using a transoral approach appears to be a safe, reliable, and function-preserving surgical method for the management of unstable atlas fractures. For this type of fracture, a transoral approach with anterior fixation should be considered as an alternative to posterior approaches or conservative treatments.

The posterior inverted L-shaped approach would not involve osteotomy, tendotomy or division of muscles, while allowing satisfied visualization of the entire posterior aspect of tibial plateau and appropriate placement of hardware. This approach is a safe and effective way for the treatment of posterior bicondylar tibial plateau fractures.

Microenvironmental conditions can influence the differentiation and functional roles of mesenchymal stem cells (MSCs). Recent studies have suggested that an inflammatory microenvironment can significantly affect the osteogenic differentiation of MSCs. Here, we show, for the first time, that IL-10 has concentration-dependent, dual roles in the osteogenesis of human bone marrow mesenchymal stem cells (hBMSCs). Low physiologic concentrations of IL-10 (0.01-1.0 ng/ml) activate the p38/MAPK signaling pathway to promote the osteogenesis of hBMSCs, but higher pathologic doses of IL-10 (10-100 ng/ml) inhibit p38/MAPK signaling by activating NF-κB, inhibiting osteogenesis. These results demonstrate that p38/MAPK and NF-κB signaling mediates the double-edged sword effect of IL-10 on hBMSCs. The osteogenic impairment was reversed at higher doses of IL-10 when cells were supplemented with the NF-κB inhibitor BAY11-7082. These data provide important insights into the regulatory effects of IL-10 on the biologic behavior of hBMSCs.-Chen, E., Liu, G., Zhou, X., Zhang, W., Wang, C., Hu, D., Xue, D., Pan, Z. Concentration-dependent, dual roles of IL-10 in the osteogenesis of human BMSCs via P38/MAPK and NF-κB signaling pathways.

C2-C3 posterior short-segment fixation and fusion is an effective method for the management of unstable Hangman's fracture, proving its value as a technique for achieving solid bony fusion combined with a low rate of complications.

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