Unilateral Biplanar Screw-Rod Fixation Technique for the Treatment of Odontoid Fractures in Patients with Atlantoaxial Bone or Vascular Abnormalities.

OBJETIVE: This study aims to introduce the unilateral biplanar screw-rod fixation (UBSF) technique (a hybrid fixation technique: 2 sets of atlantoaxial screws were placed on the same side), which serves as a salvage method for traditional posterior atlantoaxial fixation. To summarize the indications of this technique and to assess its safety, feasibility, and clinical effectiveness in the treatment of odontoid fractures. METHODS: Patients with odontoid fractures were enrolled according to special criteria. Surgical duration and intraoperative blood loss were documented. Patients were followed up for a minimum of 12 months. X-ray and computerized tomography scans were conducted and reviewed at 1 day, and patients were asked to return for computerized tomography reviews at 3, 6, 9, and 12 months after surgery until fracture union. Recorded and compared the Neck Visual Analog Scale and Neck Disability Index presurgery and at 1 week and 12 months postsurgery. RESULTS: Between January 2016 and December 2022, our study enrolled 7 patients who were diagnosed with odontoid fractures accompanied by atlantoaxial bone or vascular abnormalities. All 7 patients underwent successful UBSF surgery, and no neurovascular injuries were recorded during surgery. Fracture union was observed in all patients, and the Neck Visual Analog Scale and Neck Disability Index scores improved significantly at 1 week and 12 months postoperative (P < 0.01). CONCLUSIONS: The UBSF technique has been demonstrated to be safe, feasible, and effective in treating odontoid fractures. In cases where the atlantoaxial bone or vascular structure exhibits abnormalities, it can function as a supplementary or alternative approach to the conventional posterior C1-2 fixation.

Efficacy Analysis of Percutaneous Endoscopic Lumbar Discectomy Combined with PEEK Rods for Giant Lumbar Disc Herniation: A Randomized Controlled Study.

Objective: This study describes a randomized controlled trial that assesses percutaneous endoscopic lumbar discectomy (PELD) combined with a polyetheretherketone (PEEK) rod in patients with GLDH (herniation affecting 50% of the sagittal diameter of the spinal canal) and reports the 2-year follow-up outcome. Methods: In all, 243 patients were randomly assigned to undergo PELD or PELD combined with a PEEK rod by generating random numbers with a random number generator. Clinical outcome data, including the numerical rating scale (NRS), were used to assess the patients' back and leg pain, while the Oswestry Disability Index (ODI) was used to quantify pain and disability. Imaging data included intervertebral disc height (IDH), range of motion (ROM), and modified Pfirrmann grades. Results: At the final follow-up, the NRS for back and leg pain and the ODI scores were significantly decreased in both groups. The NRS for back pain and the ODI scores in the PELD + PEEK group (1.32 ± 0.70, 14.10 ± 4.74) were better than those in the PELD group (1.91 ± 0.69, 16.93 ± 4.33) (P < 0.05). The IDH of the PELD + PEEK group (10.54 ± 1.62) was significantly higher than that in the PELD group (9.98 ± 1.90) (P < 0.05). The IDH of the PELD + PEEK group (10.54 ± 1.62) was significantly higher than that in the PELD group (9.98 ± 1.90) (P < 0.05). The IDH of the PELD + PEEK group (10.54 ± 1.62) was significantly higher than that in the PELD group (9.98 ± 1.90) (. Conclusion: For symptomatic patients with GLDH, both PELD and PELD combined with a PEEK rod showed good efficacy. However, the long-term effect of PELD combined with a PEEK rod is better than that of PELD alone. Moreover, PELD combined with a PEEK rod can effectively reduce the recurrence rate. Maximum benefit can be gained if we adhere to strict selection criteria for PELD combined with a PEEK rod.

[Effectiveness of percutaneous endoscopic technique in treatment of intraspinal cement leakage after percutaneous vertebroplasty].

Objective: To evaluate the feasibility and safety of percutaneous endoscopic technique in the treatment of intraspinal cement leakage after percutaneous vertebroplasty (PVP). Methods: Between May 2014 and March 2016, 5 patients with lower limb pain and spinal cord injury caused by intraspinal cement leakage after PVP, were treated with percutaneous endoscopic spinal decompression. Of 5 cases, 3 were male and 2 were female, aged from 65 to 83 years (mean, 74.4 years). The course of disease was 10-30 days (mean, 16.2 days). Imageological examinations confirmed the levels of cement leakage at T 12, L 1 in 3 cases, and at L 1, 2 in 2 cases; bilateral sides were involved in 1 case and unilateral side in 4 cases. Two patients had lower limb pain, whose visual analogue scale (VAS) were 8 and 7; 3 patients had lower extremities weakness, whose Japanese Orthopedic Association (JOA) 29 scores were 18, 20, and 19. According to American Spinal Injury Association (ASIA) impairment scale, neural function was rated as grade E in 2 cases and grade D in 3 cases. Results: The operation time was 55-119 minutes (mean, 85.6 minutes), and the blood loss was 30-80 mL (mean, 48 mL). CT scan and three-dimensional (3D) reconstruction at 1 day after operation showed that cement leakage was removed in all patients. Five cases were followed up 6-21 months (mean, 12 months). In 2 patients with lower limb pain, and VAS score was significantly decreased to 2 at last follow-up. In 3 patients with lower extremities weakness, the muscle strength was improved progressively, and the JOA29 scores at last follow-up were 21, 23, and 22. Conclusion: Percutaneous endoscopic technique for intraspinal cement leakage after PVP is safe, effective, and feasible.

Canonical Wnt signaling acts synergistically on BMP9-induced osteo/odontoblastic differentiation of stem cells of dental apical papilla (SCAPs).

Dental pulp/dentin regeneration using dental stem cells combined with odontogenic factors may offer great promise to treat and/or prevent premature tooth loss. Here, we investigate if BMP9 and Wnt/ß-catenin act synergistically on odontogenic differentiation. Using the immortalized SCAPs (iSCAPs) isolated from mouse apical papilla tissue, we demonstrate that Wnt3A effectively induces early osteogenic marker alkaline phosphatase (ALP) in iSCAPs, which is reduced by ß-catenin knockdown. While Wnt3A and BMP9 enhance each other's ability to induce ALP activity in iSCAPs, silencing ß-catenin significantly diminishes BMP9-induced osteo/odontogenic differentiation. Furthermore, silencing ß-catenin reduces BMP9-induced expression of osteocalcin and osteopontin and in vitro matrix mineralization of iSCAPs. In vivo stem cell implantation assay reveals that while BMP9-transduced iSCAPs induce robust ectopic bone formation, iSCAPs stimulated with both BMP9 and Wnt3A exhibit more mature and highly mineralized trabecular bone formation. However, knockdown of ß-catenin in iSCAPs significantly diminishes BMP9 or BMP9/Wnt3A-induced ectopic bone formation in vivo. Thus, our results strongly suggest that ß-catenin may play an important role in BMP9-induced osteo/ondontogenic signaling and that BMP9 and Wnt3A may act synergistically to induce osteo/odontoblastic differentiation of iSCAPs. It's conceivable that BMP9 and/or Wnt3A may be explored as efficacious biofactors for odontogenic regeneration and tooth engineering.

Bone morphogenetic protein-9 effectively induces osteo/odontoblastic differentiation of the reversibly immortalized stem cells of dental apical papilla.

Dental pulp/dentin regeneration using dental stem cells combined with odontogenic factors may offer great promise to treat and/or prevent premature tooth loss. We previously demonstrated that bone morphogenetic protein 9 (BMP9) is one of the most potent factors in inducing bone formation. Here, we investigate whether BMP9 can effectively induce odontogenic differentiation of the stem cells from mouse apical papilla (SCAPs). Using a reversible immortalization system expressing SV40 T flanked with Cre/loxP sites, we demonstrate that the SCAPs can be immortalized, resulting in immortalized SCAPs (iSCAPs) that express mesenchymal stem cell markers. BMP9 upregulates Runx2, Sox9, and PPARγ2 and odontoblastic markers, and induces alkaline phosphatase activity and matrix mineralization in the iSCAPs. Cre-mediated removal of SV40 T antigen decreases iSCAP proliferation. The in vivo stem cell implantation studies indicate that iSCAPs can differentiate into bone, cartilage, and, to lesser extent, adipocytes upon BMP9 stimulation. Our results demonstrate that the conditionally iSCAPs not only maintain long-term cell proliferation but also retain the ability to differentiate into multiple lineages, including osteo/odontoblastic differentiation. Thus, the reversibly iSCAPs may serve as an important tool to study SCAP biology and SCAP translational use in tooth engineering. Further, BMP9 may be explored as a novel and efficacious factor for odontogenic regeneration.

Adenovirus-mediated gene transfer in mesenchymal stem cells can be significantly enhanced by the cationic polymer polybrene.

Mesenchymal stem cells (MSCs) are multipotent progenitors, which can undergo self-renewal and give rise to multi-lineages. A great deal of attentions have been paid to their potential use in regenerative medicine as potential therapeutic genes can be introduced into MSCs. Genetic manipulations in MSCs requires effective gene deliveries. Recombinant adenoviruses are widely used gene transfer vectors. We have found that although MSCs can be infected in vitro by adenoviruses, high virus titers are needed to achieve high efficiency. Here, we investigate if the commonly-used cationic polymer Polybrene can potentiate adenovirus-mediated transgene delivery into MSCs, such as C2C12 cells and iMEFs. Using the AdRFP adenovirus, we find that AdRFP transduction efficiency is significantly increased by Polybrene in a dose-dependent fashion peaking at 8 µg/ml in C2C12 and iMEFs cells. Quantitative luciferase assay reveals that Polybrene significantly enhances AdFLuc-mediated luciferase activity in C2C12 and iMEFs at as low as 4 µg/ml and 2 µg/ml, respectively. FACS analysis indicates that Polybrene (at 4 µg/ml) increases the percentage of RFP-positive cells by approximately 430 folds in AdRFP-transduced iMEFs, suggesting Polybrene may increase adenovirus infection efficiency. Furthermore, Polybrene can enhance AdBMP9-induced osteogenic differentiation of MSCs as early osteogenic marker alkaline phosphatase activity can be increased more than 73 folds by Polybrene (4 µg/ml) in AdBMP9-transduced iMEFs. No cytotoxicity was observed in C2C12 and iMEFs at Polybrene up to 40 µg/ml, which is about 10-fold higher than the effective concentration required to enhance adenovirus transduction in MSCs. Taken together, our results demonstrate that Polybrene should be routinely used as a safe, effective and inexpensive augmenting agent for adenovirus-mediated gene transfer in MSCs, as well as other types of mammalian cells.