Comparison of the effect on the paraspinal muscles cross-section areas and functional outcomes of vertebral body tethering to selective thoracic fusion in patients with idiopathic adolescent scoliosis

Objective: To aim the effect and functional results of lumbar VBT on paraspinal and psoas major muscle morphology, lumbar region range of motion by comparing vertebral body tethering (VBT) application applied to the lumbar region with selective thoracic fusion (STF). Materials and methods: 8 patients who underwent lumbar VBT and 8 patients who underwent STF with a similar follow-up period were included in the study. Patients' SRS-22 (Scoliosis Research Society-22) scores, VAS (Visual Analog Scale) and ODI (Oswestry Disability Index) scores, lumbar range of motion, trunk flexion-extension strength and endurance were compared. Paraspinal and psoas major muscle cross-section areas and fatty degeneration degrees were evaluated before and after the surgery. Results: There was no significant difference between both groups' SRS-22, VAS, and ODI scores. Both groups had similar lumbar range of motion, trunk flexion-extension strength, and endurance. There was no difference between paraspinal and psoas major muscle cross-section areas and the degrees of fatty degeneration in the preoperative and final controls of the patients. Conclusion and Discussion: VBT applied to the lumbar region can be a successful treatment method for patients with lumbar curvature, which does not cause iatrogenic damage to the paraspinal muscles of the lumbar region, does not severely restrict the lumbar range of motion, and whose functional results are satisfactory in a 2-year follow-up period.