Anterior Vertebral Body Tethering for Idiopathic Scoliosis: Two-Year Results.

Samdani, Amer F.; Ames, Robert J.; Kimball, Jeff S.; Pahys, Joshua M.; Grewal, Harsh; Pelletier, Glenn J.; Betz, Randal R. Less

Spine., Post Acceptance: June 11, 2014

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Study Design. Retrospective review

Objective. To report the 2-year results of the initial cohort undergoing anterior vertebral body tethering (VBT).

Summary of Background Data. Anterior VBT is a promising new technique with abundant preclinical studies but very few clinical results. It is a growth modulation technique, which utilizes patients' growth to attain progressive correction of their scoliosis. We report 2-year results of the initial cohort undergoing this procedure.

Methods. After obtaining IRB approval, we retrospectively reviewed our first 11 consecutive patients who underwent anterior VBT with 2-year follow-up. We collected pertinent preoperative, intraoperative, and most recent clinical and radiographic data. Student's t-test and Fisher's exact test were utilized to compare different time points.

Results. 11 patients with thoracic IS (8 female) were identified, with a mean age of 12.3 +/- 1.6 years. Preoperatively, all were skeletally immature (Sanders mean = 3.4+/-1.1, Risser mean = 0.6+/-1.1). All underwent tethering of an average of 7.8 +/- 0.9 (range 7-9) levels with the most proximal being T5 and the most distal L2. Preoperative thoracic Cobb angle averaged 44.2+/-9.0[degrees] and corrected to 20.3+/-11.0[degrees] on first erect, with progressive improvement at 2 years (Cobb = 13.5+/-11.6[degrees],% correction = 70%, p-value <0.00002). Similarly, the preoperative lumbar curve of 25.1 +/- 8.7[degrees] demonstrated progressive correction (first erect = 14.9 +/- 4.9[degrees], 2 year = 7.2 +/- 5.1[degrees],% correction = 71%, p-value <0.0002). Thoracic axial rotation as measured by a scoliometer went from 12.4+/-3.3[degrees] preoperatively to 6.9+/-3.4[degrees] at the most recent measurement (p <0.01). No major complications were observed. As anticipated, two patients returned to the operating room at 2 years postoperatively for loosening of the tether to prevent overcorrection.

Conclusion. Anterior VBT is a promising technique for skeletally immature patients with idiopathic scoliosis. This technique can be performed safely and can result in progressive correction.

(C) 2014 by Lippincott Williams & Wilkins