Analysis using three-dimensional simulation software for spinal screw placement and computed tomographic scan images.To assess the feasibility of achieving multiple (three or four) screw fixation points in C2 vertebra by using a combination of pedicle and laminar screws.Secure C2 fixation using multiple screws is required or beneficial in some unique cases. However, to the best of our knowledge, there have been no reports analyzing the feasibility of multiple screw fixation in C2.We used 1.0-mm interval computed tomographic scan images of 100 patients (50 men and 50 women) and screw trajectory simulation software. The diameter of all screws was set at 3.5 mm, considering its common usage in real surgery. The anatomical feasibility of placing both pedicle and laminar screws on the same side was evaluated. For all feasible sides, the three-dimensional distance between the screw entry points was measured.In 85% of cases, both pedicle and laminar screws could be placed on both sides, allowing for the insertion of 4 screws. In 11% of cases, 2 screws could be placed on one side, while only 1 screw was feasible on the other side, resulting in the placement of 3 screws. In all 181 sides where both types of screws could be inserted, the distance between their entry points exceeded 16.1 mm, which was sufficient to prevent the collision between the screw heads.C2 vertebra can accommodate three (11%) or four (85%) screws in 96% of cases.
Retrospective interventional study.To introduce a free-hand pedicle screw (PS) insertion technique without fluoroscopic guidance in the C7 vertebra and evaluate the procedure's feasibility and radiologic outcomes.Although PS insertion at C7 has been recognized as a critical procedure in posterior cervical fusion surgery, conventional techniques for C7 PS have several limitations.Thirty two patients (64 screws) who underwent PS insertion in C7 with the novel technique were included in this study. Postoperative clinical and radiological outcomes were evaluated. Special attention was paid to the presence of any problems in the screw position including cortical breaches of the PS and encroachment of the PS into the spinal canal or the vertebral foramen. This novel technique for PS insertion in C7 without fluoroscopy guidance had three key elements. First, the ideal PS entry point was chosen near the C6-7 facet joint using preoperative images. Second, the convergent angle distance was measured at axial computed tomography (CT) imaging, which defined the distance between the tip of C7 spinous process and the extended line passing through the pedicle axis from the ideal entry point. Third, the cranial-caudal angle distance was measured in sagittal CT images, which defined the distance between the tip of the C7 spinous process and the extended line passing through the pedicle axis.Cortical breach on postoperative CT images was observed in three screws. All violated only the lateral wall of the affected pedicle. The breached screws occurred in the initial five cases. Postoperative neurologic deterioration was not observed in any patient, regardless of cortical breaching.The novel technique successfully allows for C7 PS to be placed and is associated with a low rate of cortical breach.
Study Design: A prospective observational cohort study.Objectives: This study was conducted to analyze associations between the volume of the fusion mass and clinical outcomes 1 year after posterior lumbar interbody fusion (PLIF). Summary of Literature Review:No study has investigated associations between the size of the fusion mass and clinical outcomes after PLIF. Materials and Methods:The volume of the fusion mass and its clinical correlations after PLIF were analyzed in all patients and in subgroups.When a sufficient amount of local bone was available for grafting, only local bone without a graft extender was used (LbG group, n=20).If an inadequate amount of local bone was present for grafting, a local bone graft with porous hydroxyapatite bone chips was used (LbHa group, n=20).The same amount of demineralized bone matrix was used in both groups.The primary outcome was the relationship between the size of the fusion mass and clinical outcomes in all patients 1 year after surgery.The secondary outcome was a comparison of the size of the fusion mass and clinical outcomes by group.Results: The volume of the fusion mass was not correlated with any clinical outcomes 1 year after surgery, either in the overall group of patients or in the subgroup analysis. Conclusions:The volume of the interbody fusion mass was not related to any clinical outcomes 1 year after surgery.Furthermore, in cases with an insufficient amount of local bone for grafting, porous hydroxyapatite could be a relatively good alternative as a graft extender.
Background: The efficacy of brace application for the treatment of osteoporotic compression fractures remains unclear. The purpose of this study was to compare the treatment outcomes in patients with osteoporotic compression fractures with regard to whether the patients had no braces, rigid braces, or soft braces. Methods: We randomly assigned sixty patients with acute one-level osteoporotic compression fractures within three days of injury to the no-brace, soft-brace, and rigid-brace groups through 1:1:1 allocation. The primary outcome was the baseline adjusted Oswestry Disability Index score at twelve weeks after compression fracture. The non-inferior margin of the Oswestry Disability Index was set at an average of 10 points. Results: The baseline adjusted Oswestry Disability Index score at twelve weeks after compression fracture in the no-brace group was not inferior to that in the soft-brace or rigid-brace groups. The mean adjusted Oswestry Disability Index score was 35.95 points (95% confidence interval, 25.42 to 46.47 points) in the no-brace group and 37.83 points (95% confidence interval, 26.77 to 48.90 points) in the soft-brace group, with a difference of −1.88 points (95% confidence interval, −7.02 to 9.38 points) between the groups. Similarly, the mean adjusted Oswestry Disability Index score was 35.95 points (95% confidence interval, 25.42 to 46.47 points) in the no-brace group and 33.54 points (95% confidence interval, 23.79 to 43.29 points) in the rigid-brace group, with a difference of 2.41 points (95% confidence interval, −7.86 to 9.27 points) between the groups. During the follow-up assessment period, there was no significant difference among the groups for the overall Oswestry Disability Index scores (p = 0.260), visual analog scale for pain scores for back pain (p = 0.292), and anterior body compression ratios (p = 0.237). However, the Oswestry Disability Index scores and the visual analog scale scores for back pain significantly improved with time after the fractures (p < 0.001), and the body compression ratios significantly decreased with time in all three groups (p < 0.001). Conclusions: The Oswestry Disability Index scores for the treatment of compression fractures without a brace were not inferior to those with soft or rigid braces. Moreover, the improvement in back pain and progression of anterior body compression were similar among the three groups. Level of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.
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