Introduction. Pedicle subtraction osteotomy is a powerful technique for correcting sagittal imbalance in ankylosing spondylitis. There has been significant perioperative morbidity associated with this technique in the peer review literature. We present the Royal National Orthopaedic Hospital experience with a single surgeon retrospective study that was conducted to evaluate the outcomes in patients who underwent lumbar pedicle subtraction osteotomy for the correction of thoracolumbar kyphotic deformity in ankylosing spondylitis. Method. Twenty seven patients underwent a lumbar pedicle subtraction osteotomy and adjacent level posterior instrumentation between 1995 and 2010. There were 18 males and 9 females in the study. Events during the peri-operative course and post-operative complications were recorded. The radiological outcome and patient satisfaction were analysed with mean follow-up of one and a half years. Results. The mean operative time was three and half hours and the mean blood loss was 2290mls. Final follow-up radiograph showed an increase in lumbar lordosis angle from 17 degrees to 45 degrees. The sagittal imbalance improved by 85mm with the operation. Complications included loosening in two patients, one transient neurologic deficit and one infective non-union occurred overall. There were no mortalities from the surgery. Two patients developed junctional kyphosis and required a repeat operation. There was an improvement in the Oswestry Disability Score from a mean of 29 to 16 after the surgey. All (100%) of the patients were satisfied with the results of the procedure and would recommend the surgey to others. Conclusion. The study shows that pedicle subtraction extension osteotomy is effective for the correction of kyphotic deformity in ankylosing spondylitis

Objective: To emphasize the need to provide a controlled method of intra-operative reduction to correct fixed cervical flexion deformities in ankylosing spondylitis and to describe the technique involved. Design: The treatment of severe fixed cervical flexion deformity in ankylosing spondylitis represents a challenging problem that is traditionally managed by a corrective cervicothoracic osteotomy. The authors describe a method of controlled surgical reduction of the deformity, which eliminates saggital translation and reduces the risk of neurological injury. Subjects: 2 male patients aged 39 and 45 years old with ankylosing spondylitis presented with severe fixed flexion deformity of the cervical spine. Both patients had previously undergone a lumbar extension osteotomy to correct a severe thoracolumbar kyphotic deformity. As a result of the fixed cervical flexion deformity, marked restriction in forward gaze with ‘chin on chest’ deformity, feeding difficulties and personal hygiene were encountered in both. Their respective chin-brow to vertical angle was 60 and 72°. Somatosensory and motor evoked potentials were used throughout surgery. A combination of cervical lateral mass screws and thoracic pedicle screws were used. Interconnecting malleable rods were then fixed at the cervical end, thereby allowing them to slide through the thoracic clamps thus achieving a safe method of controlled closure of the cericothoracic osteotomy. When reduction was achieved, definitive pre-contoured titanium rods were interchanged. Halo-jacket was not considered necessary in view of the segmental fixation used. Results: Good anatomical reduction was achieved, with near complete correction of the deformities, restoration of saggital balances and forward gazes. There were no neurological deficits in either patient and the postoperative recoveries were uneventful. Both osteotomies united with no deterioration noted at 2 years. Conclusions: We illustrate a controlled method of surgical reduction during corrective cervicothoracic osteotomy of fixed cervical kyphosis in ankylosing spondylitis. This has been achieved with the use of a combination of cervical lateral mass screws and thoracic pedicle screws with interconnecting malleable rods that were later replaced with titanium rods. The authors believe that the unique technique described remains a technically demanding but adequate and safe approach for correcting such challenging deformities

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