Maria Repanti

Evolution of Disc Degeneration in Lumbar Spine: A Comparative Histological Study Between Herniated and Postmortem Retrieved Disc Specimens

This is a prospective comparative histological study on blood supply between lumbar herniated discs and postmortem retrieved ones. The aim of this study is to observe the evolution of disc degeneration in relation to its blood supply changes. Disc vascularization is present early in life, but the nucleus pulposus becomes avascular after adolescence. Vascularization of the annulus fibrosus (AF) probably also occurs late in life in association with degenerative changes and in response to trauma. Capillary neoformation and hypervascularity in degenerated discs have also been mentioned, based on animal cases. In the present study, intervertebral lumbar disc specimens were surgically removed from 84 patients with an average age of 41 years (range 24-60 years) operated on for disc herniation. In addition, control autopsy specimens were selected from 24 cadavera with an age of 39 years (range 24th gestation week to 80 years). The material was fixed in neutral buffered formalin, and 4-microm-thick sections were stained with hematoxylin-eosin and reticulin. In addition, with use of an immunohistochemical avidin-biotin complex technique, paraffin sections were stained for Ulex europaeus agglutinin receptors (UEA-1) after binding UEA-1 to the tissue. In surgical specimens, small blood vessels were identified in 45% of the disc cases. They were of the capillary-type vessels and were intermingled with proliferating endothelial cells, fibroblasts, and few mononuclear cells. All of them were located along the edges of the surgically retrieved fibrocartilage fragments. Sometimes thin bands of fibrin were attached to them and extravasated erythrocytes were occasionally seen. In autopsy specimens, blood vessels were identified in 78% of the retrieved discs. In contrast to the edge neovascularity observed in surgical specimens, capillaries were observed at the outer layer of AF surrounded by dense hyalinized and inactive-appearing collagen. From these results it is concluded that the blood vessels in extruded tissue from every type of herniation are newly formed, possibly through metaplasia of undifferentiated mesenchymal cells. It is also possible that they are derived from blood vessels that have invaded the AF as a result of disc degeneration. The finding of detection of progressive disc degeneration in both groups after 20-25 years seems to be of special interest because disc degeneration is a process that may not be directly correlated to disc herniation in these age groups.

Anterior decompression and fusion for Aspergillus osteomyelitis of the lumbar spine associated with paraparesis

Study Design A very rare case of Aspergillus fumigatus osteomyelitis of the spine is described. The differential diagnosis, medical and operative treatment, and follow-up evaluation are reported. Objectives To increase knowledge about the pathogenesis and treatment of vertebral osteomyelitis resulting from Aspergillus and to emphasize that such cases still exist. Summary of Background Data Vertebral osteomyelitis from Aspergillus species is an infrequently described disease in Europe and only few cases have been previously reported. Methods A 48-year-old woman with Aspergillus fumigatus spondylitis in the lumbar spine and tuberculosis-lung infection and concomitant debilitating systemic disease was afflicted with incomplete paraplegia and underwent successful combined operative and medical treatment. Results and Conclusions Early anterior decompression with spinal fusion, combined with Amphotericin B therapy, was crucial in bringing about complete neurologic recovery and maintaining the sagittal lumbar profile. Excellent clinical and radiologic results were shown in the 42-month follow-up period.

Evolution of aggressive granulomatous periprosthetic lesions in cemented hip arthroplasties.

The authors analyzed the histologic findings from material retrieved during 17 revision operations from 15 patients who had cemented total hip arthroplasty or hemiarthroplasty. In 13 patients, the indication for revision was aseptic loosening. In four patients, technical error during implantation of the prostheses made revision necessary. The histologic pictures in the loosened and nonloosened prostheses were similar, characterized by the presence of a synovial-like membrane at the site corresponding to the hip joint cavity or abutting the implant, underneath which were found aggregates of histiocytes and foreign-body giant cells within a dense fibrous matrix. The main foreign material in all patients consisted of fine granules or larger cement particles. A few polyethylene fibers were also observed in some patients. Metal deposits were found in three patients with titanium alloy implants and extensive loosening. The most interesting aspect of this series was the opportunity it provided to study the progressive development of the synovial-like membrane and the first appearance of the cement granulomas in non-loosened cases. The first signs of the synovial membrane appeared 2.5 months postoperatively, whereas the first cement debris were observed as early as seven months after the implantation of the prosthesis. The hip joint newly formed membrane in the nonloosened cases did not differ histologically from that in the loosened cases. Because the histology of loosened and technically poorly placed nonloosened-prostheses are the same, the authors believe that the mechanism of failure associated with cell macrophage-mediated osteolysis may be the same.