Extracorporeal Spinal Orthosis-Fixation With Progressive Distraction for Severe Spinal Tuberculosis Kyphosis: A Technical Case Series With Long-Term Follow-Up

Study Design: Retrospective technical case series. Objective: To describe the technical feasibility and long-term outcomes and radiographic experience of an extracorporeal spinal orthosis-fixation (ESOF) device combined with a progressive-adaptive distraction in highly selected patients with severe multilevel spinal tuberculosis (TB) kyphosis. Summary of Background Data: Severe spinal TB with extensive vertebral destruction may result in marked kyphosis, spinal shortening, and substantial bone loss. Conventional reconstruction can be technically challenging when multiple contiguous vertebral segments(≥3) and a Cobb Angle of ≥70° are involved. The feasibility of gradual deformity correction combined with progressive spinal lengthening in this severe setting has not been well described. Materials and Methods: Three patients with severe multilevel spinal TB deformity were retrospectively reviewed. They had extensive vertebral destruction involving three to seven vertebral segments and a preoperative Cobb Angle of ≥70°. Treatment consisted of anterior debridement and bone grafting, posterior placement of extra-long pedicle screws with an ESOF device, and postoperative progressive-adaptive distraction. Simultaneously, anti-TB drug treatment was administered for one and a half years before, during, and after surgery, including at the lesion site and during postoperative traction. Clinical and radiographic observations included Cobb Angle, spinal-pelvic tilt, standing height, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), Oswestry Disability Index (ODI), neurological status, and complications during three phases: distraction orthopedic phase, distraction osteogenesis phase, and long-term follow-up, respectively. Results: The mean preoperative Cobb Angle was 80.3°. During the initial distraction phase, lasting a mean of 71.3 days, the mean Cobb Angle decreased to 21.7°, and the mean standing height increased by 5.3 cm. During the subsequent distraction osteogenesis phase, lasting a mean of 2 years 4 months, the mean Cobb Angle was 12.7° and the mean height gain reached 7.0 cm, with radiographic evidence of new bone formation. At a mean follow-up of 12.3 years, the mean Cobb Angle was 17.0°, the mean height gain was 6.7 cm, and the mean ODI was 3.0. One patient developed a mild screw-hole infection that resolved with local wound care; two patients reported painless lumbar popping. No neurological deterioration or other major adverse event was observed. Conclusions: In this small, highly selected retrospective technical series, ESOF combined with progressive-adaptive distraction was technically feasible and was associated with substantial deformity correction and long-term maintenance of spinal alignment. These observations should be considered preliminary proof-of-concept findings rather than evidence establishing the safety or efficacy of the technique. Further studies are required to determine reproducibility, complication rates, and clinical effectiveness.