Intervertebral disc (IVD) degeneration (IDD), a highly prevalent pathological condition worldwide, is widely associated with back pain. Treatments available compensate for the impaired function of the degenerated IVD but typically have incomplete resolutions because of their adverse complications. Therefore, fundamental regenerative treatments need exploration. Mesenchymal stem cell (MSC) therapy has been recognized as a mainstream research objective by the World Health Organization and was consequently studied by various research groups. Implanted MSCs exert anti-inflammatory, anti-apoptotic, and anti-pyroptotic effects and promote extracellular component production, as well as differentiation into IVD cells themselves. Hence, the ultimate goal of MSC therapy is to recover IVD cells and consequently regenerate the extracellular matrix of degenerated IVDs. Notably, in addition to MSC implantation, healthy nucleus pulposus (NP) cells (NPCs) have been implanted to regenerate NP, which is currently undergoing clinical trials. NPC-derived exosomes have been investigated for their ability to differentiate MSCs from NPC-like phenotypes. A stable and economical source of IVD cells may include allogeneic MSCs from the cell bank for differentiation into IVD cells. Therefore, multiple alternative therapeutic options should be considered if a refined protocol for the differentiation of MSCs into IVD cells is established. In this study, we comprehensively reviewed the molecules, scaffolds, and environmental factors that facilitate the differentiation of MSCs into IVD cells for regenerative therapies for IDD.

Case: Coronal shear fractures of the hamate are relatively rare injuries. Surgical intervention is recommended for displaced fractures. However, there is no established surgical procedure for the displaced coronal shear fractures of the hamate. Therefore, we present 2 cases of the displaced coronal hamate fracture with metacarpal dislocations, which were successfully managed with open reduction and internal fixation, using the headless compression screw by the 2-directional approach. Conclusion: Our procedure ensured that the screw's distal end captured the hamate hook, and the displaced bone fragments were reduced considerably in both cases.

Purpose Cervical pedicle screws (CPS) inserted with template-guided systems (TGS) have a low perforation rate. However, only a few case studies have been reported, and the risk factors for perforation remain unknown. This study aimed to evaluate the accuracy of CPS placement using TGS in a large case series and analyze the risk factors for CPS perforation. Methods This was a retrospective clinical evaluation of prospectively enrolled patients. Eighty consecutive patients who underwent CPS insertion using TGS were included in the study. Overall, 437 CPS were inserted using TGS. Computed tomography was used to evaluate CPS positions and radiographic parameters of CPS and vertebrae. Furthermore, comparisons of patient background factors and radiographic parameters were performed between the perforated and non-perforated screw groups. Results A total of 413 (94.5%) screws were completely inside the pedicle, 22 (5.0%) screws deviated by < 2 mm, and 2 (0.5%) screws deviated by > 2 mm and < 4 mm. Therefore, 435 (99.5%) screws were considered clinically acceptable. The perforation rate was the highest in C4 (12.5%). No neurovascular injury was observed. In comparisons between the perforated screw group and the non-perforated screw group, low height, low weight, low BMI, female sex, fellow surgeon, and narrow pedicle were considered as risk factors for CPS perforation using TGS. Conclusion CPS placement using the TGS showed very high clinical accuracy. Body size, sex, surgeon’s experience, and pedicle width may affect the accuracy of CPS placement using TGS.