Thirteen consecutive patients with scoliosis, treated with anterior spinal fusion with a single rigid rod, were followed up clinically and radiographically for 19 months. The mean major curve, 52° preoperatively, improved to 10° at follow-up. The results of anterior single-rod spinal fusion in patients with idiopathic scoliosis are excellent. No development of kyphosis or incidence of hardware failure was seen.
From April 2001 to January 2003, 60 patients were selected for a circumferential fusion with an ALIF Brantigan cage and posterior titanium instrumentation. The aim of this study was to analyse the complications and the effects of circumferential fusion on functional outcome and lumbar lordosis. Circumferential fusion restored lordosis, provided a higher fusion rate, and showed a tendency towards better functional outcome and reduced back and leg pain.
The aim of this study was to evaluate the effect of hyaluronic acid on the stability of the functional spinal unit (FSU) after discectomy. The study included 20 Cercopithecus monkeys. Through a left retroperitoneal approach, four FSUs were exposed and nucleotomy performed. On one level a simple nucleotomy was done, while hyaluronic acid was inserted into one space, hylaform into another, and hylaform and bone morphogenetic protein (BMP)-2 into the fourth. The specimens were evaluated radiologically and histologically at the University of Marburg, Germany. The vertebral height of all segments remained mostly unchanged. Insertion of hylaform with BMP-2 led to ossification in 30%. There was no ossification after insertion of hyaluronic acid alone or in 10% of simple nucleotomies. The insertion of hyaluronic acid shows a promising capability of preventing disc collapse after nucleotomy and may enhance the favourable outcome of minimally invasive procedures.
Reviewing 40 consecutive cases over a two-year period, we tested the efficacy of variable screw plate fixation postoperatively. A Codman plate was used in all cases. We compared radiological preoperative measurements of the kyphotic angle and disc height with immediate postoperative measurements and measurements at a mean of eight months postoperatively. In no case was there an increase in kyphotic angle. Disc height remained within two mm of that shown on immediate postoperative radiographs. We concluded that satisfactory results are obtained with variable screw plate fixation, with no compromised stability.
Evaluating the effectiveness of conservative treatment of odontoid fractures, from 1997 to 1999 we reviewed 22 cases. All were treated first in halo traction and subsequently by halo thoracic brace immobilisation. We used Anderson and D’Alonzo’s classification of types I to III. The mean follow-up time was seven months. Initial displacement was measured radiologically and union was evaluated. In type-II fractures, the incidence of pseudarthrosis was 40%. Fractures with more than 5 mm of initial displacement and more than 10° angulation all went on to nonunion, suggesting that type-II fractures should be treated by internal fixation.
Anatomisches Institut der Georg-August-Universität Göttingen, Germany Biomedical Research Centre, Dept. of Orthopaedic Surgery, Academic Hospital, Pretoria, South Africa To date, no animal model for disc degeneration has gained much acceptance, mostly due to the fact that most animals are quadrupeds and thus lack basic biomechanical characteristics of human spines. An adequate model would be of invaluable interest for degeneration related research. In a standardized series of animal experiments in 18 adult Minipigs and 20 adult Cercopithecus aethiops monkeys all animals obtained nucleotomy in one lumbar FSU from a ret-roperitoneal approach and were sacrificed at last 24 weeks afterwards. The Minipigs were x-rayed at time of sacrifice, the monkeys prior to operation and at termination of the experiment. Vice versa, the Minipigs obtained intradiscal pressure recordings at these occasions. The Minipig spines were formol fixed whereas the monkey spines were harvested after perfusion with PBS, fresh frozen, and obtained CT and MRI scans prior to thawing, fixation and comprehensive histological evaluation. The lumbar FSU of Minipig and Cercopithecus mainly consists of the same elements as in man. There are certain differences concerning the porcine endplates which ossify as an epiphyseal-like formation with ossification starting in its center, different from the so-called “Randleiste”. Whereas the operative procedure in the Minipigs came in handy, in the Cercopithecus monkey it proved to be demanding, though feasible, due to relatively wide transverse processes and thick psoas muscle structures. The psoas could not be easily detached and needed to be split instead, thus directly exposing the segment nerves. The histological, standard radiological, CT, MRI, and mechanical observations were very similar to those which can be made during the natural aging process of the disc in man. Both animal models are recommendable for further research: Cercopithecus FSUs are more difficult to expose. Logistic reasons may favour Minipigs in Europe. In case of fusion related experiments the use of primates yet seems inevitable.
