Two-level lumbar total disc replacement: functional outcomes and segmental motion after 4 years.

INTRODUCTION: Lumbar total disc replacement is an effective treatment for single-level discogenic lower back pain. But the replacement of two disc levels is controversial. HYPOTHESIS: Two-level total disc replacement will improve function while preserving spinal motion. MATERIAL AND METHODS: A continuous series of 108 patients (51 women, 57 men) surgically treated over two levels with the ProDisc-L implant (Synthes Spine) was evaluated retrospectively with an average follow-up of 4 years. Ninety-three of these patients were operated for L4/L5 and L5/S1 degenerative disc disease, while 15 were operated for L3/L4 and L4/L5 disease. The procedure was carried out through the left retroperitoneal approach in 65 patients, the right retroperitoneal approach in 42 patients and both approaches in 1 patient. The Oswestry score, lumbar VAS and radicular VAS were used to evaluate function. The motion of the prosthetic disc segments was evaluated using Cobb's method. Data were collected prospectively in the context of regular patient monitoring. A retrospective analysis was carried out by an independent examiner. RESULTS: The procedure led to a statistically significant improvement in the functional scores. The motion of the upper disc segment was 9° (0°-19°) in flexion/extension and 5.5° (2°-12°) in lateral bending. It was 6.2° (0°-14°) and 1.9° (0°-7°) at the lower disc segment. The range of motion was similar in L3/L4 and L4/L5, but was less in L5/S1. Lack of mobility was not correlated with alterations in the functional outcome. The complication rate was 18%. DISCUSSION: Two-level lumbar disc replacement improves spinal function while preserving its mobility. But this procedure is fraught with risks and must be carried out by a highly-experienced team. A longer follow-up is needed to evaluate the sustainability of the results and to detect any adjacent segment disease. The French National Authority for Health (HAS) has recommended against two-level lumbar disc replacement, so it no longer can be performed in France.

[Mechanical testing of implant properties of thoracoscopic implantation of ventral spinal stabilizing systems. Comparative study with the ISO/DIS 12189-2 corpectomy model and an improved synthetic model]. / Mechanische Testung der Implantateigenschaften eines thorakoskopisch implantierbaren ventralen Wirbelsäulenstabilisierungssystems. Vergleichende Betrachtung im Korpektomiemodell nach ISO/DIS 12189-2 und in einem neuartigen synthetischen Modell.

A new modular anterior fixation system MACS TL (modular anterior construct system for the thoracic and lumbar spine) has been developed for use in thoracoscopic spondylodesis. This system demonstrates high angular stability and meets the surgical requirements for an endoscopic approach. The objective of the current study was fatigue testing of the MACS TL implant system using a corpectomy model according to ISO/DIS 12189-2 and a synthetic model recently developed by Kotani et al. [6]. The MACS TL system demonstrated good mechanical properties with a high stiffness compared to the published data reviewed. The importance of dynamic testing in a corpectomy model has been demonstrated by comparing the MACS TL plate system with an early prototype, which has not yet been clinically evaluated. The corpectomy model according to Kotani et al. offers an interesting alternative to the ISO/DIS 12189-2 test method for asymmetrically designed and antero-laterally positioned spinal implants due to the unconstrained ball joint.

Percutaneous interbody osteosynthesis in the treatment of thoracolumbar traumatic or tumoural lesions. A review of 51 cases.

The authors describe a technique of percutaneous interbody osteosynthesis applicable to the dorsal and lumbar spine. 51 patients were so treated for different aetiologies: traumatic conditions (35 cases) and tumoural lesions (16 cases). The material used consisted of special instruments that are positioned in double obliquity by a percutaneous posterolateral approach. A posterior approach limited to the pathological focus was used jointly whenever a graft or a decompression was necessary (19 cases). Several types of anaesthesia were used (local, local-regional, general, neuroleptanalgesia). The patients benefited by the advantages that usually accompany percutaneous techniques. The advantages and limitations of the method are discussed.

[Total hip arthroplasty in the presence of sepsis]. / L'arthroplastie totale de hanche en milieu septique.

Sixty-seven cases of total arthroplasty of the hip in the presence of sepsis performed between 1974 and 1986 were reviewed. These prostheses were inserted in 57 cases to replace septic prostheses. Forty-six were infected total hip prostheses and 11 were infected head and neck replacement femoral prostheses. In 10 cases arthroplasty was performed for subacute septic arthritis, usually secondary to trauma. In seven cases, a simple revision of the prosthesis by excision and lavage of infected tissues was performed. In 51 cases, a total hip replacement arthroplasty was performed in one stage. When one of the components was not loose it was preserved; in 17 cases the femoral cement was retained and in six the acetabular cup was retained. In eight cases, the prosthesis was removed, excision of the tissues was made and a total hip arthroplasty inserted after a minimum interval of six months. As regards infection, success was achieved in 69 per cent of cases rising to 85 per cent after secondary removal of the prosthesis. In relation to function, a good or fair result was achieved in 72 per cent of cases. The results were favourable in 81 per cent of cases with complete exchange of prostheses and in 75 per cent with preservation of the femoral cement. Preservation of the acetabular cup was only successful in 40 per cent of cases. Accessory factors in the prognosis were the addition of a bone graft, which became incorporated in 29 cases out of 30 and the nature of the organism which was of no significance, except that staphylococcus epidermidis and Koch's bacillus proved to be more easy to treat.

[Morphology and anteroposterior body equilibrium in spondylolisthesis L5-S1]. / La morphologie et l'équilibre corporel antéro-postérieur dans le spondylolisthésis L5-S1.

The authors have studied standard radiographs of 200 patients with lumbosacral spondylolisthesis, 52 of whom had been treated operatively. The radiographic technique is described. It allows measurement of pelvic retroversion and its influence on the appearance of slipping. The shape of the sacrum is not a consequence of the position of the pelvis but can alter during growth. Trunk imbalance may lead to increased stress with fracture of the pars interarticularis. Observation of these features makes it possible to follow the development of the deformity and to adopt appropriate treatment.