Thoracolumbar fracture reduction by percutaneous in situ contouring

Abstract

Purpose: Percutaneous in situ contouring is based on bilateral bending of rods on the spine, thus increasing lordosis at the fracture. It was analyzed if this technique would provide a better reduction than prone positioning and how sagittal alignment would behave.

Methods: Twenty-nine patients were operated using in situ contouring and selective anterior fusion for non-neurologic A2, A3 or B2 fractures. Clinical results were assessed prospectively using visual analog scale (VAS) and Oswestry Disability Index (ODI). The radiographic deformity correction was measured by sagittal index and regional kyphosis. Sagittal balance was assessed using kyphosis, lordosis, T9 tilt, pelvic incidence, pelvic tilt and sacral slope. Posterior wall fragment reduction was evaluated by computed tomography.

Results: After 2 years, VAS and ODI were comparable to the status prior to the accident. The sagittal index was 19.7° preoperatively, 5.3° after prone positioning and -1.1° after in situ contouring (p < 0.001). The loss of correction was 2.4°, mainly during the first 3 months. Similar observations were made for regional kyphosis. The sagittal spino-pelvic alignment was stable postoperatively. A preoperative canal obstruction ≥50 % was observed in 16 patients, and the fragments migrated anteriorly in all patients.

Conclusions: Percutaneous instrumentation and anterior fusion provides good clinical results. In situ contouring increases lordosis obtained by prone positioning. Anterior column lengthening and ligamentotaxis reduce posterior wall fragments, which decompress the canal without laminectomy. The fusion of anterior defects prevents the loss of correction and provides a stable sagittal profile. The instrumentation may be removed without damaging the paravertebral muscles and loss of correction.

Fig. 1

Principle of in situ contouring, showing the initial position of instrumentation. Arrows indicate the correction mechanism by bending rods (a), which increases lordosis and reduces the fracture by anterior column lengthening and ligamentotaxis. Anterior defect fused by a secondary video-assisted approach (b)

Fig. 2

Posttraumatic kyphotic deformity (a) reduced by prone positioning (b) and bending the rods in situ (c), which leads to an anterior gap in the cranial disc, secondarily filled with a cage containing bone graft harvested from the fractured vertebra and rib (d)

Fig. 3

Posttraumatic kyphosis of an A2 fracture of L2 measured by sagittal index (SI) and regional kyphosis (RK) on radiographs (a), CT reconstruction (b) and intraoperative reduction maneuver by pushing the bending irons together (c) under fluoroscopic control (d)

Fig. 4

Postoperative radiographs of percutaneous instrumentation from T12 to L4 with selective anterior fusion at L1–L2 (a, b) and clinical aspect of posterior and anterior approaches (c, d) of the same patient as in Fig. 3

Fig. 5

Postoperative CT at 1 year follow-up showing L1–L2 fusion (a) and mobilization of the lumbar spine in flexion–extension after percutaneous removal of the instrumentation (b, c) of the same patient as in Fig. 3

Fig. 6

Preoperative CT (a, c) and postoperative control after fracture reduction (b, d) showing posterior wall displacement and the effect of increasing lordosis by in situ contouring, which pulls the fragments anteriorly and decompresses the canal