Thoracic Elongation in Type III Osteogenesis Imperfecta Patients With Thoracic Insufficiency Syndrome

Study Design. Prospective patient series. Objective. To evaluate outcome of children experiencing severe osteogenesis imperfecta (OI) with thoracic insufficiency syndrome (TIS), who were treated with a novel expandable spinothoracic fixation device. Summary of Background Data. Current treatment options for TIS in patients with OI are limited. As in other patients with TIS, thoracic elongation is the treatment of choice; however, the use of vertical expandable prosthetic titanium rib device is contraindicated for patients with poor bone quality. Methods. From 2007 to 2009, 4 patients with type III OI with TIS, aged 8 to 12 years, were treated with a novel expandable spinothoracic fixation device. Pre- and postoperative mobility, Cobb angle, Po-2, Pco(2), forced vital capacity, forced expiratory flow, use of accessory muscles when breathing, body weight, complication rates, and patient satisfaction were assessed. Results. Prior to surgery, 2 patients were wheelchair bound and 2 walked with assistive devices. Average follow-up was 24 months (range, 14-36 mo). Mean Cobb angle improved by up to 32% in the coronal plane. Pulmonary function improved in all patients, with mean increases of 45% in forced vital capacity, 93% in forced expiratory flow, and 43% in Po-2. Pco(2) declined 30% on average, returning to normal values. Mean patient weight at 6-month follow-up increased by 10.9%. Patients moved from less than 3rd weight percentile per age group to the 3rd to 7th percentiles at the 6-month follow-up, with continuing weight gain. There were no major complications. All patients and their caregivers were satisfied that the procedure led to improved self-image and functional level. Conclusion. Thoracic elongation improved pulmonary function, facilitated weight gain, and made an indirect correction of spinal deformities (Cobb angle) by more than 30%, with no significant complications. Because of the rarity of this condition, a multicenter study to gain experience in a larger number of patients is recommended.