Computed tomography scan morphometric study of adolescent vertebral laminae: From three-dimensional reconstruction to laminar hook

INTRODUCTION: The authors report a descriptive analysis of spine computed tomography (CT) scan to describe the anatomy of the laminae of T2 and T3 vertebrae. The aim of the study was to establish reference data in the adolescent population. These data could be useful to improve the effectiveness of laminar hooks. Hook-claw anchorage has been considered as one of the best choices in terms of safety and durability in the spine surgery. MATERIALS AND METHODS: We systematically reviewed CT scans of 14–16-year-old healthy individuals who underwent CT scans in other indications than scoliosis during a 2-year period. Patients with spine, chest, or bone disease were excluded. The Risser sign was ≥ 2. CT scan data were converted into a three-dimensional reconstruction. RESULTS: Seven hundred and fifty measures were collected from 30 CT scans matching with the inclusion/exclusion criteria. The mean age was 15-years old. Gender was mixed. Mean T2 lamina's upper half height was 8.9 mm (8.2–9.6) corresponding to a thickness of 7.1 mm (6.6–7.7). Mean T3 lamina's lower half height was 9.0 mm (6.9–10.4) corresponding to a thickness of 7.3 mm (6.8 à 7.9). DISCUSSION: No previous study reported these data in adolescents. Laminae in adolescents appeared to be slightly oversized in this study relative to the previous reports in adults. It seems that the intracanal part length of the hook and depth of the gorge should be adapted in order to improve fitting of the implant with laminae. CONCLUSION: This study brings new data in the knowledge of anatomical characteristics of the vertebras that should help to improve safety and stability of implants as laminar hook and hook claw.