PEDICLE SUBTRACTION OSTEOTOMY FOR FIXED THORACOLUMBAR SAGITTAL IMBALANCE

Abstract

Object. Our purpose is to evaluate early benefits and complications of pedicle subtraction osteotomy (PSO) for patients with fixed thoracolumbar kyphotic deformities.

Background. The fixed sagittal imbalance is a syndrome in which the patient is only able to stand with the weight-bearing line in front of the sacrum [1]. Its etiology could be very different, but usually it is due to idiopathic scoliosis or degenerative sagittal imbalance [2]. Different techniques are reported in the literature for its correction [3]. In particular, in the last few years, the PSO is affirming as a good technique in correcting the fixed thoracolumbar sagittal deformity, with its three column osteotomy [1–3].

Materials and Methods. From December 2005 to July 2006 the first 10 PSOs for patients with fixed symptomatic thoracolumbar sagittal deformity were performed in our Spine Center. All 10 were female (100%). Mean age was 63.8±5.3 (55–71). The diagnosis was idiopathic scoliosis in 7 cases (70%), degenerative sagittal imbalance in 3 (30%). Patients had undergone a mean of 1.5±0.97 (0–3) operative procedures prior to the PSO.

Results. A pedicle subtraction was always performed between the level L1 and L4. An average of 10±2.9 (7–16) vertebral levels were included in the spinal fusion. Intraoperative estimated blood loss was 1300±305 (800–1800) mL, operative time was 298.5±37.5 (250–360) minutes. An average increase in lumbar lordosis of 28.3±12.1 (8–51) degree was established with this technique: the transpedicular wedge resection contributed 73.5%±25.4% (19.4±6.1 degree) of this correction; the remaining correction came from multilevel facetectomy. The average improvement in the sagittal plumb line was 4.3±5.1 (from −5 to +15) cm. There were 8 (80%) perioperative complications: 4 major (1 subdural hematoma; 1 pulmonary embolism; 1 fracture of the upper end vertebrae; 1 pemanent neurologic deficit); 4 minor (1 transient neurologic deficit; 3 wound dehiscences). Most patients reported improvement in terms of pain and self image as well as overall satisfaction with the procedure.

Conclusions. Pedicle subtraction osteotomy is a useful procedure in correcting fixed sagittal thoracolumbar imbalance. Often it is well-tolerated, but certainly this is a technically demanding procedure with high perioperative complication rates.