The Effect of Vertebral Body Tethering on Lumbar Paraspinal Muscle Cross-Section Area in Adolescent Idiopathic Scoliosis

We aimed to compare the paraspinal muscle cross-section area and functional results of anterior vertebral tethering and selective thoracic fusion surgery.

Idiopathic scoliosis is a three-dimensional deformity of the spine. It is defined as the curvature of the spine of 10° or more detected radiologically in the coronal plane. In scoliosis, changes in axial rotation in the transverse plane and physiological curvatures in the sagittal plane (decrease or increase in kyphosis, lordosis) occur.

The incidence of scoliosis is 2-3%, but up to 10% of patients need surgical treatment. Knowing the long-term effects of posterior spinal fusion is currently the gold standard treatment because it gives good results in deformity improvement. However, fusion surgery has disadvantages such as loss of motion in the spine and long-term development of adjacent segment disease and disc degeneration. It has also been suggested that spinal fusion causes iatrogenic damage to the paraspinal muscles (especially the multifidus), which is of great importance in the alignment and movement of the spine due to the posterior approach during surgery.

As a result of damage to the lumbar multifidus muscles and the development of fatty degeneration, problems such as spinal sagittal alignment disorders and chronic low back pain can be seen. In addition, fatty degeneration and atrophy of the paraspinal muscles may lead to the development of adjacent segment disease in the segments under fusion in the long term.

In selective thoracic fusion, by protecting the mobile segments in the lumbar region, the range of motion is preserved and iatrogenic damage of the lumbar paraspinal muscles is prevented. After selective thoracic fusion (STF), some improvement occurs in the deformity in the lumbar region. However, the risk of insufficient improvement and progression of the curve in the unfused lumbar segments, especially in immature patients, should be considered.

Anterior vertebra body tethering is a surgical technique that has been used more frequently in recent years, which is thought to prevent functional complications caused by spinal fusion.With this method, which allows the growth of the spine to continue, there is no need for fusion when treating progressive curvature. Short-term radiological results of this surgical technique have been reported frequently in recent years, but the literature on functional results (spine flexibility, trunk endurance, etc.) is very limited.

In our study, we plan to evaluate the effects of AVT applied to the lumbar region on paraspinal muscle quality, trunk muscle strength and endurance, and trunk joint range of motion by evaluating patients who underwent selective thoracic fusion surgery and patients who underwent thoracic fusion + AVT to the lumbar region.

Eligibility Criteria:
Inclusion Criteria:

Males or females age 12 to 19 years old Diagnosis of idiopathic scoliosis At least 6 months have passed since surgical intervention Spina bifida occulta is permitted

Exclusion Criteria:

Pregnancy Prior spinal or chest surgery MRI abnormalities (including syrinx greater than 4mm, Chiari malformation, or tethered cord) Neuromuscular, thoracogenic, cardiogenic scoliosis, or any other non-idiopathic scoliosis Associated syndrome, including Marfan syndrome or neurofibromatosis