RESUMO
Background: Concerns regarding the primary stability of early adjustable loop button (ALB) devices for cortical fixation of tendon grafts in anterior cruciate ligament reconstruction (ACLR) have led to the development of new implant designs. Purpose: To evaluate biomechanical stability of recent ALB implants in comparison with a continuous loop button (CLB) device. Study Design: Controlled laboratory study. Methods: ACLR was performed in a porcine model (n = 40) using 2-strand porcine flexor tendons with a diameter of 8 mm. Three ALB devices (Infinity Button [ALB1 group]; Tightrope II RT [ALB2 group]; A-TACK [ALB3 group]) and 1 CLB device (FlippTack with polyethylene suture) were used for cortical tendon graft fixation. Cyclic loading (1000 cycles up to 250 N) with complete unloading were applied to the free end of the tendon graft using a uniaxial testing machine, followed by load to failure. Elongation, stiffness, yield load, and ultimate failure load were recorded and compared between the groups using a Kruskal-Wallis test with post hoc Dunn correction. Results: Elongation after 1000 cycles at 250 N was similar between groups (ALB1, 4.5 ± 0.7 mm; ALB2, 4.8 ± 0.8 mm; ALB3, 4.5 ± 0.6 mm; CLB, 4.5 ± 0.8 mm), as was load to failure (ALB1, 838 ± 109 N; ALB2, 930 ± 89 N; ALB3, 809 ± 103 N; CLB, 842 ± 80 N). Stiffness was significantly higher in the ALB1 group compared with the CLB group (262.3 ± 21.6 vs 229.3 ± 15.1 N/mm; P < .05). No significant difference was found between the 4 groups regarding yield load. Constructs failed either by rupture of the loop, breakage of the button, or rupture of the tendon. Conclusion: The tested third-generation ALB devices for cortical fixation in ACLR withstood cyclic loading with complete unloading without significant differences to a CLB device. Clinical Relevance: The third-generation ALB devices tested in the present study provided biomechanical stability comparable with that of a CLB device. Furthermore, ultimate failure loads of all tested implants exceeded the loads expected to occur in the postoperative period after ACLR.
RESUMO
BACKGROUND AND OBJECTIVES: The primary treatment modality for spinal meningiomas (SM) is surgical resection. In recent years, minimal invasive spine surgery has gained considerable popularity, attributing its growth to advancements in surgical technologies and improved training of surgeons. Nonetheless, the suitability and effectiveness of minimal invasive spine surgery for intradural spinal tumor resection remain a subject of debate. In this cohort study, we aimed to compare the extent of resection of the unilateral hemilaminectomy approach, a less invasive technique, with the more traditional and invasive bilateral laminectomy. METHODS: We performed a retrospective cohort study including patients with SM who underwent surgery at our department between 1996 and 2020. Cohorts included patients who underwent tumor resection through bilateral laminectomy and patients who underwent a unilateral hemilaminectomy. The primary end point was extent of resection according to the Simpson classification. RESULTS: Of 131 with SM, 36 had a bilateral laminectomy and 95 were operated through a unilateral hemilaminectomy. In both groups, gross total resection, Simpson grades 1 and 2, was achieved in 94.44% and 94.74%, respectively (P = .999). The neurological outcome was also comparable in both cohorts (P = .356). Both length of hospital stay and estimated blood loss were significantly lower in the unilateral cohort (P < .05). CONCLUSION: The results of this study indicate that the unilateral hemilaminectomy yields comparable results in both oncological and neurological outcome when compared with the bilateral laminectomy. Thus, unilateral hemilaminectomy may serve as a viable and safe alternative for the surgical removal of SM.
