RESUMEN
BACKGROUND: Surgical simulation is a valuable educational tool for trainees to practice in a safe, standardized, and controlled environment. Interactive feedback-based virtual reality (VR) has recently moved to the forefront of spine surgery training, with most commercial products focusing on instrumentation. There is a paucity of learning tools directed at decompression principles. The purpose of this study was to evaluate the efficacy of VR simulation and its educational role in learning spinal anatomy and decompressive techniques. METHODS: A VR simulation module was created with custom-developed software. Orthopaedic and neurosurgical trainees were prospectively enrolled and interacted with patient-specific 3D models of lumbar spinal stenosis while wearing a headset. A surgical toolkit allowed users to perform surgical decompression, specifically removing soft tissues and bone. The module allowed users to perform various techniques in posterior decompressions and comprehend anatomic areas of stenosis. Pre- and post-module testing, and utility questionnaires were administered to provide both quantitative and qualitative evaluation of the module as a learning device. RESULTS: 28 trainees were enrolled (20-orthopaedic, 8-neurosurgery) in the study. Pre-test scores on anatomic knowledge progressively improved and showed strong positive correlation with year-in-training (Pearson's r = 0.79). Following simulation, the average improvement in post-test scores was 11.4% in junior trainees (PGYI-III), and 1.0% in senior trainees (PGYIII-Fellows). Knowledge improvement approached statistical significance amongst junior trainees (p = 0.0542). 89% of participants found the VR module useful in understanding and learning the pathology of spinal stenosis. 71% found it useful in comprehending decompressive techniques. 96% believed it had utility in preoperative planning with patient-specific models. CONCLUSIONS: Our original VR spinal decompression simulation has shown to be overwhelmingly positively received amongst trainees as both a learning module of patho-anatomy and patient-specific preoperative planning, with particular benefit for junior trainees.
RESUMEN
PURPOSE: This biomechanical study compared the stability of four different ramus fracture fixation methods for Type C pelvic ring injuries in the absence of posterior fixation. METHODS: A 5-mm vertical osteotomy of the mid-superior and inferior pubic ramus was created in 12 synthetic pelvic models. Four surgical constructs were compared: (1) two-pin AIIS external fixation, (2) 3.5-mm reconstruction plating, (3) bicortical, fully threaded 3.5-mm, and (4) 6.5-mm pubic ramus screws. Specimens were tested in a simulated one-legged stance on a hemiarthroplasty implant in three stages: (1) no applied load, (2) application of the loading fixture preload to the sacrum (6N), and (3) following six cycles of a 250N load. Stability was assessed based on resultant displacement of the fracture sites at the superior ramus and the anterior sacroiliac joint. RESULTS: The bicortical, fully threaded 6.5-mm pubic ramus screw provided the most stable ramus fracture fixation (0.5 ± 0.4 mm) displacement under load and was the only construct to finish testing without gross posterior pelvic disruption. Plate constructs finished the final loading stage with only a small increase (3.1 ± 2.3 mm) in ramus fracture gap size, but had significant displacement at the SI joint (>20 mm). 3.5-mm screw constructs had 1.6 ± 0.7 mm of ramus displacement in the preload stage, but had complete posterior pelvic disruption (>20 mm) that prevented further testing. External fixation was unstable at the ramus and sacroiliac sites in the initial setup. CONCLUSIONS: The bicortical, fully threaded 6.5-mm pubic ramus screw was the only anterior fixation construct tested that controlled motion at both the anterior and posterior pelvic rings in the absence of posterior fixation.