ABSTRACT
The evolution of osteosynthesis has led to the development of novel miniplate designs, including 3-dimensional (3D) miniplates, which offer improved biomechanical stability. However, mandible fractures resulting from the high impact have a complex fracture configuration. Hence, the authors developed interlocking 3D miniplate to overcome the difficulty in miniplate and screw placement to avoid critical anatomic structures, that is, dental roots and nerve, while still providing stability for the fracture fragments. The interlocking 3D miniplates can be formed according to the specific needs by adjusting the horizontal and vertical cross struts configuration. This study describes a design process of interlocking 3D miniplates and evaluates biomechanical performance compared to standard miniplates. Finite element analysis was performed to evaluate the design's stress state using human and goat mandible models under various loading conditions. After the authors, established that our design was feasible for fabrication, the authors developed the prototype for biomechanical testing. Biomechanical testing was conducted on 10 goat mandibles to compare stability and displacement under various load between the interlocking 3D miniplate and the standard miniplate configuration. Biomechanical testing revealed reduced displacement in all directions with the interlocking 3D miniplate compared to the standard miniplate. Furthermore, there was a significant difference in all loads in the buccal-lingual displacement (P<0.05). The novel interlocking 3D miniplate design shows an adequate ability to provide stability for fixation for mandibular fractures, as evidenced by finite element analysis and biomechanical testing. Further research is necessary to validate these findings and explore the clinical application of interlocking 3D miniplates in mandibular fracture management.
ABSTRACT
BACKGROUND: Adolescent idiopathic scoliosis remains a major problem due to its high incidence, high risk, and high cost. One of the aims of the management in scoliosis is to correct the deformity. Many techniques are available to correct scoliosis deformity; however, they are all far from ideal to achieve three-dimensional correction in scoliosis. AIM: To develop a set of tools named Scoliocorrector Fatma-UI (SCFUI) to aid three-dimensional correction and to evaluate the efficacy, safety, and functional outcome. METHODS: This study consists of two stages. In the first stage, we developed the SCFUI and tested it in finite element and biomechanical tests. The second stage was a single-blinded randomized clinical trial to evaluate the SCFUI compared to direct vertebral rotation (DVR). Forty-four subjects with adolescent idiopathic scoliosis were randomly allocated into the DVR group (n = 23) and SCFUI group (n = 21). Radiological, neurological, and functional outcome was compared between the groups. RESULTS: Finite element revealed the maximum stress of the SCFUI components to be between 31.2 - 252 MPa. Biomechanical analysis revealed the modulus elasticity of SCFUI was 9561324 ± 633277 MPa. Both groups showed improvement in Cobb angle and sagittal profile, however the rotation angle was lower in the SCFUI group (11.59 ± 7.46 vs 18.23 ± 6.39, P = 0.001). Neurological and functional outcome were comparable in both groups. CONCLUSION: We concluded that SCFUI developed in this study resulted in similar coronal and sagittal but better rotational correction compared to DVR. The safety and functional outcomes were also similar to DVR.
ABSTRACT
Objective: Until now, the spondylolisthesis reduction technique has relied on posterior instrumentation using long arm pedicle screws. In this way, the segments will be brought into alignment with the other vertebrae with the pedicle mats being tightened. The aim of this study is to acknowledge whether reduction surgery for degenerative lumbar spondylolisthesis (DLS) using long arm pedicle screws is able to correct the listhesis and spinopelvic parameters. Methods: We carried out a retrospective study of patients with degenerative lumbar spondylolisthesis who went through reduction surgery using long arm pedicle screws in our institutions from January 2019 to March 2022. Preoperative and postoperative radiological outcomes consisting of listhesis and spinopelvic parameters were assessed. Results: We found a statistical difference between the magnitude of listhesis immediately after surgery and preoperatively (p<0.001), with a successful correction of 85.85%. There was significant decrease in the value of pelvic tilt (p=0.044) and increase in the value of sacral slope (p=0.008) after surgery. Conclusion: Reduction surgery using long arm pedicle screws for DLS was able to reduce the listhesis effectively up to 85.5%, and also to restore the parts of spinopelvic parameters, the pelvic tilt and sacral slope, approaching normal values.
