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The dysregulation of ubiquitin ligase is the cause of many human diseases. Tripartite motif protein 32 (TRIM32) is an E3 ubiquitin ligase whose role in nucleus pulposus (NP) cell apoptosis is unclear. The expression of TRIM family protein and β-catenin in 40 NP tissue samples was detected by RT-PCR. Interleukin (IL)-1β or tumor necrosis factor (TNF)-α was used to treat rat NP cells. Knockdown and overexpression of Trim32 were achieved using specific siRNA and recombinant plasmids. Western blotting, RT-PCR, and flow cytometry were used to assess the expression of TRIM32/β-catenin and the apoptosis rate of NP cells. Coimmunoprecipitation was adopted to analyze the possible interactions between AXIN1 and TRIM32. In clinical samples, TRIM32 expression was of positive relevance with the expression of CTNNB1 (β-catenin). In vitro, apoptosis of IL-1β- or TNF-α-treated rat NP cells was induced through upregulated Trim32 expression and activated β-catenin signaling, whereas Trim32 siRNA and inhibition of β-catenin reversed the induction effect of cytokines. Further studies indicated that TRIM32 activated the β-catenin signaling pathway through ubiquitination of AXIN1, thereby regulating apoptosis. Collectively, this study reveals that TRIM32 promotes inflammatory factor-induced apoptosis of rat NP cells, in part by direct degradation of AXIN1 to trigger β-catenin signaling.

Study Design. A retrospective case series study with at least 10 years of follow-up data. Objective. To validate the reliability of bilateral C1–2 transarticular screws and C1 laminar hooks and a bone autograft for acute pediatric atlantoaxial instability. Summary of Background Data. The reliability of initial posterior atlantoaxial fusion in pediatric patients is still controversial. To date, however, only a few published articles with short-term follow-up data are available to help spinal surgeons understand the effects of posterior atlantoaxial fusion in the skeletally immature spine. Methods. Five pediatric patients with acute atlantoaxial instability underwent atlantoaxial fusion using the above technique over a 3-year period. During a minimum 10-year follow-up period, not only outcomes and complications were investigated, but the vertical growth of the constructed spine in relation to the growth of the entire cervical spine, overall cervical spinal alignment, and adjacent-segment instability were evaluated. Results. The clinical follow-up indicated solid fusion and complete clinical relief from symptoms. No neural or vascular impairment was observed. The radiological evaluation showed that all patients had growth within the fusion construct reaching a mean 35.4% of the entire cervical spine. There were no radiological indicators of subaxial instability, even when cervical sagittal alignments became straight with a mean C2–7 angle of 6.4°. Conclusion. The results showed that initial posterior atlantoaxial fusion accomplished with bilateral C1–2 transarticular screws, C1 laminar hooks fixation, and bony autograft is a reliable surgical technique for treating acute pediatric atlantoaxial instability without negative effects on vertical growth at the fused level or the stability of the subaxial spine. Level of Evidence: 3

BACKGROUND A C1 laminar hook can theoretically avoid vertebral artery injury and is less technically demanding. However, only few studies with small samples analyzed the short-term outcomes of C2 pedicle screws combined with C1 laminar hooks (C2PS-C1LH) technique in the treatment of atlantoaxial dislocation. Furthermore, it is not confirmed whether similar clinical outcomes can be achieved with C1-C2 pedicle screw and rod construct (PSRC). OBJECTIVE To evaluate the outcomes of C2PS-C1LH and C1-C2 PSRC fixation techniques for treating atlantoaxial dislocation. METHODS Data of 52 patients with atlantoaxial dislocation treated by C1-C2 PSRC or C2PS-C1LH fixation were retrospectively reviewed. Outcomes evaluated by visual analog scale score for neck pain (VASSNP), Neck Disability Index (NDI), atlantodental interval (ADI), and the perioperative parameters including blood loss and operation time were analyzed and compared between 2 techniques. Patient satisfaction at final follow-up was also investigated. RESULTS There were no complications related to the surgical approach and instrumentation in either group. The mean bone fusion time was 5.06 ± 1.65 mo for the C2PS-C1LH group and 3.93 ± 0.99 mo for the C1-C2 PSRC group (P > .05). Hundred percent of fusion rates were achieved in both groups at month 12 after operation. The ADI, VAS scores, the NDI scores, and the JOA scores were greatly improved in both the groups (P < .05), but there were no significant differences between the 2 groups. CONCLUSION C2PS-C1LH fixation technique was comparable to C1-C2 PSRC in the treatment of reducible atlantoaxial dislocation. C2PS-C1LH fixation was an ideal alternative strategy to C1-C2 PSRC fixation.

To propose an independent radiological index to evaluate surgical outcomes of A type basilar invagination, a retrospective study was conducted to compare the clinical outcome between procedures 1 and 2 by applying intraoperative consistent traction and manual reduction. Moreover, the atlantodental interval (ADI), cervicomedullary angle (CMA), bilateral sagittal inclination of atlantoaxial joint (SIAA) were measured and compared to pre-operation. Postoperatively, only these patients undergoing procedure 2 achieved significant neurological improvement. The ADIs and the SIAAs decreased in both groups, these differences are statistically significant between pre- and post- operation. For postoperative CMAs, only these patients undergoing modified surgery gained significant improvement of angle with mean 141°. We concluded that the CMA or SIAA could be a radiological predictor to evaluate surgical outcome in BI, among which the CMA is a more independent and easily measurable predictor that is closely correlated with satisfactory neurological improvements. Moreover, procedure 2 with intraoperative resistant cranial traction and manual reduction can help us achieve a good CMA.