Purpose: The intervertebral disc prosthesis has been proposed as an alternative to fusion in cases of severe discal degeneration. The purpose of this study was to analyse long-term results in patients treated with a Charity III SB intervetebral disc prosthesis.

Material and methods: Clinical and radiological outcome were reviewed in 24 patients (66% women); 86% of the prostheses were L5–S1. Three patients had discectomy or nucleotomy. One patient underwent implantation at two levels. Mean age at surgery was 42 years (26–50). Eighty percent of the patients had an occupational activity and 70% were on sick leave for more than six months. Minimum follow-up was six years. Mean follow-up was eight years six months and was greater than ten years for thirteen patients. The Oswestry score, a visual analogue scale (VAS), and time to resumed occupational or sports activities were used to assess clinical outcome. Radiologically, prosthetic height, and status of adjacent discs were analysed.

Results: Outcome was considered good in 83% of the patients with an improvement in the VAS in 60% and in the Oswestry score in 50%. These results persisted at last follow-up. Twelve patients achieved excellent outcome with VAS at 0 and Oswestry at 10. For the occupationally active patients, 90% resumed their activities, 70% at three months and 80% at the same activity level. Only two patients were on disability compensation. Radiologially, prosthesis flexion-extension was scored 8 at level L4–L5, and 5 at level 5-S1 and persisted at last follow-up. There were no cases of spontaneous fusion or decreased prosthetic height. The status of a suprajacent disc degenerated in one patient requiring L4–L5 fusion nine years after disc implantation. There were two complications (8%): one eventration and one anterior dislocation six days after insertion of an L5–S1 prosthesis in the one patient who underwent a two-level procedure and required secondary fusion.

Conclusion: In light of this series with a sufficient follow-up, intervertebral disc prosthesis appears to be a satisfactory alternative to arthrodesis in well selected young patients with a single level of disc degeneration.

Purpose of the study: To analyse post-operative imbalance after C.D.I. (Cotrel Dubousset Instrumentation) for idiopathic scoliosis according to the fused area, particularly the lower level of fusion. To recall a classification for determination of fusion area based on pre-operative standing coronal radiograph.

Patients and methods: To be included in this study the patients had to have an adolescent idiopathic scoliosis, at least two years of post-operative follow up. One hundred and twenty-two patients met the criteria; mean follow-up was three years, five months (minimum two years, maximum nine years). Scoliotic curves were classified as single structural (81), double structural (41). Balance was clinically analysed by plumbline, radiographically by a plumbline dropped from C7 to the sacrum and measuring deviation from the midpoint of the sacrum in centimetres. A curve with a deviation of 10 mms or less was considered as balanced.

Results: Imbalance in single structural curves was 70% when using stable vertebra (King) or “other vertebra” (beyond stable vertebra or one or two levels upper stable vertebra). Using end vertebra (J.MOE), (elected vertebra – C. Salanova) imbalance was 10%. In double structural (41 cases) imbalance was 50% using stable, or “other vertebra” 10% when elected vertebra was fused.

Conclusion: In this study there was a strong statistical relationship between the lower level of fusion and imbalance.

Study design: To analyse the long term effect of Harrington Instrumentation and fusion to the lumbar spine in the treatment of idiopathic scoliosis.

Objectives: To demonstrate there is a relationship between the strategy used (determination of fusion area) and pain or degenerative changes.

Summary of background data: The literature has been fairly controversial in terms of pain and degenerative changes beyond a fusion for idiopathic scoliosis according as the lower level of fusion. This is the first study in which the results are analysed according as the “strategy used” and not the sole level of fusion.

Methods: 250 patients operated on by Harrington instrumentation were clinically and radiographically reviewed. Pain was classified (as Moskowitz and Moe). To be included they should have an idiopathic scoliosis, a minimum follow up of 20 years (mean 26, max 36), 37% over 30 years, had to have been under 20 years at the time of surgery, and should have a full set of radiographs.

Curves were classified according to our own classification (Salanova et al) 1973–2000 in single structural. Thoracic 114, thoraco-lumbar 21 and double structural thoracic and lumbar, true double major (52), false D.M. (45). The double thoracic was identified with permanent T1 tilt (18). On P.OP standing the lower level of fusion was identified: E.V. (Salanova et al 1973–2000) SV (King) other vertebra. On follow up radiographs standing coronal and sagittal, lumbar coronal and sagittal degenerative changes were evaluated, slipping lateral and sagittal, discopathy over 50% and classified as none, moderate, complete.

Results: Mean age at surgery 15 years + 6. Mean age at follow up 49 years. Ten patients were reoperated on for various reasons. Overall results: Pain none 70, episodic 82, frequent 42, permanent 46. Degenerative changes none 155, moderate 62, complete 23. These data were evaluated according to the strategy used; there is a strong statistical relationship between strategy and final results. Our study proves that King’s classification for so-called King II curves is misleading.

Conclusion: This study is the most important ever published in terms of patients, methodology, and follow up. It shows that if a clear analysis of curve(s) before surgery is effectuated for determination of fusion area, if for single curves the lower level of fusion is the good one and for double structural the choice between selective thoracic fusion and double fusion is correctly determinated the long term results are not so bad.