The Effect of Expansion Thoracostomy on Spine Growth in Patients with Spinal Deformity and Fused Ribs Treated with Rib-Based Growing Constructs.

Study Design: Retrospective review of prospective registries.

Objectives: We hypothesized that patients with congenitally fused ribs who underwent thoracostomy upon implantation of rib-based distraction devices would achieve improved spine growth compared with those who did not undergo thoracostomy.

Summary Of Background Data: Patients with fused ribs may develop thoracic insufficiency syndrome. Treatment for severe early-onset spinal deformity with rib fusions often includes the placement of rib-based expansion devices with surgical division of the fused ribs (thoracostomy). The effect of thoracostomy on spinal growth has not been fully examined.

Methods: Two multicenter registries of primarily prospectively collected data were searched. Patients with fused ribs and implantation of a rib-based device were identified. A total of 151 patients with rib fusions treated with rib-based constructs and minimum two-year follow-up were included. Among those, 103 patients were treated with expansion thoracostomy at the time of implantation, whereas 48 patients received device implantation alone. We evaluated change in T1-T12 and T1-S1 height, coronal Cobb angle, kyphosis, and number of surgeries. Preoperative deformity was similar between the two groups. Only 19% of patient underwent final fusion, with similar numbers fused in each group.

Results: At latest follow-up, the expansion thoracostomy group had a greater total improvement in T1-S1 height (7.2 cm vs. 4.8 cm, p = .004). There was no difference between the two groups for change in spinal height at each lengthening procedure. Interestingly, thoracostomy patients also underwent more total surgeries (11.5 vs. 9.6, p = .031) and more lengthening procedures (8.3 vs. 6.6, p = .017) than the comparison group despite similar length of follow-up.

Conclusions: Patients who underwent expansion thoracostomy at the time of rib expansion device implantation achieved greater improvement in T1-S1 height than those who underwent implantation of rib expansion device alone. Further work is needed to evaluate whether expansion thoracostomy impacts pulmonary function.