Renato de Mello Guimarães

Introduction: This study aimed to evaluate the mechanical resistance to pullout of the lumbar cortical bone trajectory (CBT) screw with and without transfixation of the second cortical in a biomechanical assay in swine vertebrae. Methods: A pullout test was performed in 16 swine vertebrae (L5 and L6) fixed with 32 CBT screws using the same protocol. Of these, 16 were inserted in a monocortical manner according to the original technique and 16 through a modified technique which included the transfixation of the second cortical bone. Results: The average maximum load value for pulling out the inserted screws with the modified technique including the transfixation of the second cortical bone was 140.50 Kgf (± 56.56), while in the original technique it was 95.69 Kgf (± 42.19) (p = 0.004). Conclusion: The biomechanical tests applied to the studied sample showed that the pullout resistance of the CBT screws inserted with the bicortical technique was, on average, 46% higher than the screws inserted according to the original monocortical technique. Level of Evidence II; Experimental study.

Introduction: This study aims to evaluate the safety of using the cortical path screw with transfixation of the second cortical bone in relation to the vascular structures. Methods: This retrospective observational study (level of evidence: III, study of non-consecutive patients) analyzed data from the medical records of patients who underwent computed angiotomography scans of the abdomen at Hospital Mater Dei, measuring, in millimeters, the distance between the point of the lumbar vertebra considered the anatomical reference for the transfixation of the second cortical bone and the vascular structures adjacent to the spine (abdominal aorta, inferior vena cava, iliac vessels, segmental lumbar arteries). Results: Forty-eight patients were evaluated, with a mean age of 60 years (±8 years, 41-75), of whom 52% were male and 48% female. The measurements obtained between the pre-vertebral vessels and the possible screw exit points did not demonstrate contact in any of the vertebrae studied. Conclusions: The measurements obtained suggest the safety of using the cortical path screw transfixing the second cortical bone. Knowing the position of the vessels is essential to reduce intra- and postoperative complications related to spinal instrumentation. Level of evidence III; Study of non-consecutive patients.

Objective: To evaluate the interobserver agreement of the new AOSpine classification for subaxial cervical fractures. Methods: A descriptive study, which11 traumatic lesions of the subaxial cervical spine (through radiographic and tomographic images), were evaluated by 16 observers being: 6 senior surgeons, 4 fellows in spinal surgery and 6 physicians residents in Orthopedics and Traumatology by the new AOSpine classification, with subsequent statistical analysis of the results. An agreement analysis was performed using the Kappa coefficient, both individually and in combination, with an interpretation of the index performed using the standardized model for Landis and Koch. To determine the level of significance of the analyzes, values less than 0.05 were considered statistically significant. Results: In general, the level of agreement among the examiners was considered reasonable. The lesions “A0 (F3)”, “A4 (F3)”, “B1”, “B3”, “B3 (F3)”, “C”, “C (F3)” and “F3”showed a low level of agreement between the examiners. The level of reasonable agreement was obtained between fractures “A0”, “A1”, “A4”, “B2” and “C (F4)”. The only fracture that presented a moderate level of agreement was the “C (F4 BL)” lesion. This result indicates that the referred injury was the fracture of the subaxial column that presented the best level of agreement among the 16 examiners in the present study. Conclusions: The results of the study indicate an intermediate agreement of the new AOSpine classification for subaxial cervical lesion and point to the need to carry out studies that seek to evaluate this new classification in order to better evaluate its strengths and weaknesses, contributing for its improvement. Level of evidence III; Diagnostic study - investigation of a diagnostic test.