Medical Student Cleveland Clinic Lerner College of Medicine Cleveland Clinic Lerner College of Medicine Cleveland, OH, US
Disclosure(s):
Mario-Cyriac T. Tcheukado, BS: No financial relationships to disclose
Introduction: Bertolotti Syndrome (BSy) is a clinical manifestation where lower back pain is attributed to the presence of a lumbosacral transitional vertebra (LSTV). There is an enlargement of the L5 transverse process forming a variable articulation with the sacrum. Little is known regarding the biomechanical influence of BSy on lumbar kinematics and the development of pain. This study aims to evaluate the biomechanical influence of BSy on lumbar kinematics to improve intervention selection.
Methods: 8 cadaveric spines (L1 to S1) were dissected and secured to a robotic testing system. Specimen-specific 3D prints simulating Type I and Type II Bertolotti Syndrome along with the native spine were attached superiorly to the left and right sides of the specimen at L5 and inferiorly to 6-axis load sensors. Pure and combined moment loading protocols were applied to the specimen while individual functional spinal unit (FSU) motions and loads at the custom prints were measured.
Results: Across all FSUs, L5-S1 motion was most affected by the print type. L5-S1 Flexion-Extension saw the greatest decrease in range-of-motion from Native Spine to Type Ib to Type IIb (5.14°±2.15° to 4.88°±1.90° to 2.62°±0.88°) while Axial Rotation and Lateral Bending saw similar trends. Minimal loads were measured when the specimen was instrumented with Native or Type I prints. Notable loads were measured during pure and combined loading when the specimens were instrumented with Type II prints (Peak compressive loads of 74N and 73N during Left Lateral Bending with Left Axial Rotation and Right Lateral Bending with Right Axial Rotation, respectively).
Conclusion : This study explored the biomechanical effects of BSy on lumbar kinematics. L5-S1 motion reduced when Bsy increased in severity, especially at Type Ib and Type IIb. This motion reduction correlates with increased contact forces at the LSTV leading to inhibited movement and theoretical increased pain sensation. Understanding these kinematic changes can help direct surgical and pain management of BSy.
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