Objective: To report on the long-term follow-up (mean 14.2 years) of patients with early onset idiopathic scoliosis treated with convex epiphysiodesis (CE) and Luque trolley instrumentation (LTI) without fusion. To evaluate factors influencing curve progression during the adolescent growth spurt in such patients.

Methods: Thirty-one cases of early onset idiopathic scoliosis with documented progression were surgically treated with CE and LTI without fusion between 1984 and 1992. Twenty-three (14 male, 9 female) of 31 cases had reached a minimum of 16 years of age at follow-up. These 23 cases were reviewed. The overlapped ‘L’ configuration of Luque trolley was used for the first 14 cases (prior to 1988), the overlapped ‘U’ configuration was used subsequently in the following 9 cases.

Results: Mean age at operation was 4.3 years (range, 1.5 – 9 years). Mean pre-operative Cobb angle was 65° (range 30° – 95°), and immediate post-operative Cobb angle was 28° (range 10° – 60°). Mean follow-up was 14.2 years (range, 7–19 years). Four cases required insertion of longer Luque rods (mean age of 7.5 years).

Definitive spinal fusion was required in thirteen cases at a mean age of 14.5 years (range 12–23 years), due to progression of scoliosis in 9 cases (mean Cobb angle 55°), and the development of junctional kyphosis in 4 cases. In ten cases the correction obtained was maintained through skeletal maturity (mean Cobb angle at final follow-up 33°). These cases did not require definitive spinal fusion.

The mean growth within the instrumented segment was 3.2 cm (42% of the expected growth). Progression of scoliosis was predicted by pre-operative apical convex rib-vertebra angle (RVA) (p=0.002). Excessive growth within the instrumented segment was predictive of junctional kyphosis but not of scoliosis progression. Age at operation and initial curve magnitude were not found to be significant predictive factors. 72% of overlapped ‘L’ rod construct (10 cases), and 33% of overlapped ‘U’ rod construct (3 cases) had documented curve progression within the adolescent growth spurt and required definitive spinal fusion.

Conclusions: CE and LTI was effective in controlling early onset idiopathic scoliosis, whilst still allowing significant growth. Pre-operative convex RVA was predictive of curve progression. The overlapped ‘U’ rod construct was more effective than the overlapped ‘L’ rod construct in preventing curve progression.

Introduction: Surgical treatment is indicated in Scheuermann’s disease with severe kyphotic deformity, and/or unremitting pain. Proximal or distal junctional kyphosis and loss of correction have been reported in the literature, due to short fusion level, overcorrection, or posterior only surgery with failure to release anterior tethering. We reviewed surgically treated Scheuermann’s kyphosis cases, to evaluate the factors affecting the sagittal balance.

Methods and results: 35 cases (22 male, 13 female) of Scheuermann’s kyphosis were treated surgically in this centre during 1993–1999. Mean age at operation was 21.5 years (14–53 years). The kyphosis was high thoracic (Gennari Type I) in two cases, mid thoracic (Type II) in 11 cases, low thoracic or thoraco-lumbar (Type III) in eight cases, and whole thoracic (Type IV) in 14 cases. Mean pre-operative kyphosis (Cobb angle) was 81° (range 70° to 110°). Ten cases (mean kyphosis 77°) had one stage posterior operation only with segmental instrumentation. Twenty-five cases had combined anterior and posterior (A-P) surgery. Fifteen cases (mean kyphosis 81°) had one stage thoracoscopic release and posterior instrumentation, and 10 cases (mean kyphosis 89°) had open anterior release, followed by second stage posterior instrumentation. Minimum follow-up was 14 months (mean 45 months, range 14–140 months). The mean post-operative kyphosis was 47.2°. Kyphosis correction achieved ranged from 39% after posterior surgery only, to 42% after thoracoscopic A-P surgery, and 48% after open A-P surgery. Mean loss of correction was 12° after posterior only surgery, 9.5° after thoracoscopic A-P surgery, and 6° after open A-P surgery. Four cases of open A-P surgery had additional anterior cages to stabilise the kyphosis before posterior instrumentation; a mean 55% kyphosis correction was achieved in this group, and there was no loss of correction. Younger cases, under 25 years (n=16) had significantly better kyphosis correction (p< 0.05). Two cases (6%) developed distal junctional kyphosis due to fusion short of the first lordotic segment, requiring extension of fusion. Four cases (12%) developed proximal junctional kyphosis requiring extension of fusion; all of them had primary posterior surgery only. Location of the curve (Gennari Type) had no significant influence on the initial curve, degree of immediate correction, or loss of correction. Complications included infection (4 cases), pneumothorax (1 case), haemothorax (1 case), instrumentation failure (3 cases); 3 cases had persistent back pain.

Conclusion: Combined anterior release and posterior surgery achieves and maintains better correction of Scheuermann’s kyphosis. Loss of correction, and proximal junctional kyphosis are more frequent after posterior surgery only, and short fusion. Use of cages anteriorly prevents loss of correction. Correction is better achieved in younger patients, but is not influenced by the location of the curve.

Objective: This study investigates whether the sequence of anterior and posterior procedure has any effect on the lordosis, disc height and stability in combined A-P fusion of the lumbar spine.

Design: A biomechanical study on cadaver lumbar spine.

Materials and Methods: Twelve motion segments (between L2–L5) from four cadaver lumbar spines were studied. Anterior and posterior stabilization were performed using a Syncage (Synthes, Switzerland) of appropriate sizes, and translaminar screws respectively. Load-deformation characteristics in flexion-extension, lateral bending, and torsion were tested in a material-testing machine (Dartec, Stourbridge, UK) with 7.5Nm cyclical load. Angular deformation of each motion segment was determined simultaneously, by 2-D optical reflex camera system (Pro-reflex, Qualysis, Sweden). Disc height, and angle of lordosis between the adjacent endplates were determined from lateral radiographs. These parameters were measured in the intact spine, after A-P fixation with front first, and after back procedure first.

Results: Compared to the intact spine, the disc height was significantly increased (p< 0.05) when Syncages were introduced before posterior fixation, but not when posterior fixation was done first (p = 0.12). The angle of lordosis was increased significantly with posterior stabilization first, but only marginally, with anterior stabilization first. The stability of the motion segments increased significantly with combined A-P fusion, compared to either anterior or posterior fixation alone. With posterior stabilization first, the stability in all directions were greater but not statistically significant, compared to anterior stabilization first (p> 0.05).

Conclusion: In combined A-P fusion of lumbar spine, the lordosis is better restored when posterior stabilization is done first, but disc height is better restored when the anterior stabilization is performed first. Stability of fixation is not significantly affected by altering the sequence.