Aim:

To compare the ability of fulcrum bend and traction radiographs to predict correction of AIS using pedicle screw only constructs and to compare the fulcrum bending correction index (FBCI) with a new measurement: the traction correction index (TCI).

To compare the ability of fulcrum bend and traction radiographs to predict correction of AIS using screw only implants and to assess the fulcrum bending correction index (FBCI) with a new measurement: the traction correction index (TCI)

Retrospective radiographic analysis of case series (Level IV)

Radiographic correction of scoliosis based on correction rate does not take into consideration the curve flexibility. It has been suggested that fulcrum bending radiographs predict curve correction in AIS [1]. This has been questioned [2] and has been suggested that traction radiographs are more predictive in a mixed group of patients with hybrid and screw only constructs.

Twenty three patients average age 15, who underwent posterior correction of scoliosis using pedicle screw only construct.

Analysis was carried out on the pre-op and immediate post-op AP radiographs and the pre-op fulcrum bend and traction radiographs. Correction rate, fulcrum flexibility, traction flexibility, FBCI and TCI was calculated.

Preoperative mean Cobb angle of 66 degrees was corrected to 25 degrees postoperatively. The mean fulcrum bending Cobb angle was 38 degrees and traction Cobb angle 28 degrees. The mean fulcrum flexibility was 45%, traction flexibility 59% and correction rate 63%. The mean FBCI was 182% and TCI was112%.

When comparing fulcrum bend and traction radiographs, we found the latter to be more predictive of curve correction in AIS using pedicle screw constructs. The TCI better takes into account the curve flexibility than the FBCI.

Study design: Retrospective study.

Objectives: To determine whether apical vertebrectomy for correction of severe spinal deformity in patients with cerebral palsy or mental retardation significantly improves curve correction and to study complications of such a procedure.

Summary of Background data: Although a combined anterior-posterior procedure for correction of severe deformity in cerebral palsy patients is well established, apical vertebrectomy to improve correction has not been described.

Subjects: 5 patients (2M, 3F) operated on between 2000–2003 (anterior apical vertebrectomy followed by posterior instrumented fusion), mean age 14 years, average follow-up 1.5 years. All had group II (Lonstein & Akbarnia) rigid (mean 96degrees bending to 83degrees) thoracolumbar/lumbar curves with marked pelvic obliquity.

Results: Preoperative mean Cobb angle of 96 degrees corrected to 36 degrees, (63% correction, and 57% correction over and above the bending Cobb angle), 42 degrees at final follow-up. Mean apical vertebral translation (AVT) correction was 57 % (86mm to 37mm) and regional AVT correction 53%. Pelvic tilt correction was 72% (29degrees to 9degrees). Thoracic kyphosis remained unchanged but lumbar lordosis of 4.2 degrees (range−66 to +68) was corrected to 63 degrees. Mean blood loss was 1100mls (range 300–3000) for anterior surgery and 3400mls for posterior surgery. Operative time was 3 hours for anterior surgery. There were no intra-operative or post-operative complications (infection, pseudarthrosis, metalwork failure). Subjective outcome was excellent in all patients.

Conclusion: In patients with rigid, rotated curves with wide apical translation, apical vertebrectomy and posterior instrumented fusion can achieve significant correction of Cobb angle over and above the bending cobb angle and also the AVT and pelvic tilt leading to high parent / caregiver satisfaction and improvement in functional status of the patient.

Study Design: Retrospective chart review.

Summary of Background Data: Spinal osteotomy in ankylosing spondylitis is performed to restore forward gaze and sagittal balance. Closing wedge lumbar osteotomy and polysegmental thoracic osteotomy in the same patient has not been reported.

Objective: To study the factors affecting correction of sagittal balance.

Subjects: 27 patients (23 male, 4 female) operated between 1989–2002: average age 46 years: minimum follow-up: 18 months. 19 patients had lumbar osteotomy alone, 6 had both lumbar and thoracic osteotomies and 2 had thoracic osteotomy alone. Three groups were identified: A) patients with decreased lumbar-lordosis and normal thoracic-kyphosis B) Normal / increased lumbar-lordosis and increased thoracic-kyphosis C) Decreased lumbar-lordosis and increased thoracic-kyphosis.

Results: Preoperatively, mean sagittal balance was +103 mm, thoracic-kyphosis 61 degrees, and lumbar-lordosis 25 degrees. Three months postoperatively, sagittal balance was +36 mm, thoracic-kyphosis 55 degrees, and lumbar-lordosis 49 degrees. At final follow-up sagittal balance was +44 mm, thoracic-kyphosis 57 degrees and lumbar-lordosis 46 degrees. In patients who had thoracic osteotomies, thoracic-kyphosis of 78 degrees was corrected to 48 degrees. There were no spinal cord injuries or permanent nerve root palsies. Six patients had deterioration of sagittal balance (SB) (> 45 mm), 5 of them required cervical osteotomy. There was significant association between post-operative thoracic-kyphosis of > 60 degrees and SB deterioration (p-value < .001, sensitivity 100%, specificity 75%). Statistically there was no significant association between SB deterioration and post-operative sagittal balance, lumbar-lordosis, osteotomy-angle and extent of fixation.

Conclusions: Correction of thoracic-kyphosis affected final sagittal balance significantly. Consideration should be given to the simultaneous performance of lumbar osteotomy and polysegmental thoracic osteotomies in selected patients to obtain greater correction and restoration of near normal sagittal balance.

Study Design: Retrospective case series.

Objective: To evaluate the clinical outcome, radiographic results and complications associated with single rod anterior instrumentation in neuromuscular thoracolumbar scoliosis.

Methods: Retrospective study with mean follow up of 35 months.

Subjects: Nine patients (6F, 3M), mean age 15 years, were operated on between 1994–2000. This heterogeneous patient group consisted of five cases of spinal dysraphism, one prune belly syndrome, one arthrogryposis, one myotonic dystrophy and one congenital myopathic dystrophy (muscle-eye-brain-syndrome). All patients were ambulatory and had minimal pelvic obliquity (< 15degrees).

Outcome measures: Pre-operative, post-operative and final follow-up measurements of Cobb angles, apical vertebral translation (AVT), thoracic kyphosis, lumbar lordosis, sagittal and coronal balance were recorded along with operative complications, pseudarthrosis, metalwork failure and loss of correction.

Results: There was one rod breakage and one case of proximal thoracic curve progression requiring supplementary posterior surgery. For the remaining 7 patients, the average corrections for Cobb angle was 62% (52 to 20 degrees), AVT was 53% (5.7 to 2.7cms), and both thoracic kyphosis and lumbar lordosis remained unchanged. No pseudarthrosis, vascular or neurological complications were encountered. Subjectively results were excellent in six and good in one.

Conclusions: Selective anterior instrumentation for neuromuscular scoliosis using a single rod resulted in acceptable clinical and radiographic outcomes in this highly selected series. Advantages include preservation of distal lumbar motion segments whilst maintaining sagittal and coronal alignment. We believe that this method of scoliosis correction has a definite yet select role in patients who are ambulatory, have minimal pelvic obliquity (< 15degrees), non-progressive pathology and near normal mental function.

Study Design: Retrospective study.

Objective: To describe a modified cervico-thoracic extension osteotomy and evaluate clinical & radiographic outcomes.

Subjects: 10 patients with fixed cervico-thoracic kyphosis, average age 56 years, minimum 12 months follow-up. Three patients had psoriatic spondyloarthropathy, Three patients had previous lumbar osteotomies.

Technique: General anaesthesia and SSEP spinal cord monitoring was used. Complete laminectomy of C7, hemilaminectomy of C6 and T1, plus pedicle subtraction osteotomy and decancellisation of C7 was performed. Upon completion of the osteotomy, controlled halo manipulation allowed closure of the osteotomy: the pivot point being the anterior longitudinal ligament. Segmental fixation with lateral mass and pedicle screws plus bone graft was then added. All patients were immobilised for three months in halo-jacket.

Results: Restoration of normal forward gaze was achieved in all patients. Mean preoperative kyphosis of 17 degrees was corrected to lordosis of 36 degrees (mean total correction 53 degrees). No spinal cord injuries or permanent nerve root palsies occurred. Three patients had mild sensory radiculopathies lasting a few weeks. No loss of correction, no pseudarthrosis, one patient had 50% anterior subluxation that later united. Two deep infections were successfully treated with wound washout and antibiotics.

Conclusions: Cervico-thoracic osteotomy in ankylosing spondylitis continues to be challenging and hazardous. C7 decancellisation and extension osteotomy supplemented with segmental internal fixation provides immediate spinal stability, reduces sagittal spinal translation and associated high risk of neurological injury, whilst maintaining correction until bony union.