Many believe the reduction in the number of mobile segments causes an increased strain in the unfused segments, predisposing them to early degeneration. This degeneration of the adjacent segment could be a cause of low back pain after spinal fusion. The clinical manifestations supporting the increased stress of the unfused segments are the significant incidence rates of spondylolisthesis, spondylolysis acquisita and spinal stenosis. However, there was a paucity of reports in the literature on the histological observation at the adjacent, unfused sgements. Therefore, the purpose of this study was to observe the histological changes of the unfused, mobile segments following fixation in the cat spine. The cat lumbar spines from L6 to L7 were fixed posteriorly with acrylic cement and wires. Histological and histochemical observation of the upper adjacent segment were performed after H-E, trichrome, reticulin and Safranin-O staining at postoperative 6 and 12 months, respectively. The results were as follows: 1. There were mild degenerative changes in the intervertebral disc, but no evidence of definitive degeneration in the articular cartilage of the facet joints at postoperative 6 months in the spinal fixation group. 2. The marked degenerative changes of the intervertebral disc were shown at postoperative 12 months in the spinal fixation group. Of 5 cats sacrificed at 12 months, 3 cats had irregular configuration of the fiber's arrangement of the annulus fibrosus. 3. At postoperative 12 months in the spinal fixation group, marked degeneration was noted on the articular cartilage of the adjacent facet joints. Through this study, it is clarified that degenerativce changes of the intervetebral disc and facet joint at the adjacent segments will develop after certain period of time following spinal fusion. Especially the facet joints of the adjacent, unfused segment were found to be most vulnerable to the adverse effects. This may be responsible for the back pain in the future after spine fusion.
Animals ; Back Pain ; Cartilage, Articular ; Cats* ; Incidence ; Intervertebral Disc ; Low Back Pain ; Reticulin ; Spinal Fusion ; Spinal Stenosis ; Spine* ; Spondylolisthesis ; Spondylolysis ; Zygapophyseal Joint

The result of clinical survey of seventy-five children with supracondylar fractures of the humerus is presented. Sixty-eight fractures had gross displacement, and seven were undisplaced ones. Seven children with undisplaced fractures were treated with simple splinting. Twenty-one fractures with gross displacement were closedly reduced and immobilized by cast. Twenty cases treated with over-head skin traction or skeletal traction, and followed by cast immobilization, and twenty-seven were operatively reduced and were fixed with 2 K-wires. The results obtained were as follows: 1. The average age of children was 6.8 years, and the male and female ratio was 2.1:l. 2. 97.1% (66 cases) was the extension type and 2.9% (2 cases) was the flexion type. 3. Good end results were obtained in the well-reduced groups, such as undisplaced fractures and surgically reduced fractures. Of 27 operated cases, 19 who had early operation without manipulative trial or traction, had excellent results, while 8 who had surgery in delay developed limitation of flexion and/or extension motion of the elbow. Of these 19, two cases developed mild extension limitation as sequella. 4. As complications, incomplete ulnar nerve palsy developed in one case, but it spontaneously recovered in 3 weeks after open reduction. During treatment utilizing the olecranon pin traction, pin tract infection developed in 2 cases, but the infection was controlled by the antibiotic administration and wound dressing. Severe cubitus varus deformity developed in 4 cases among the conservatively treated group (manipulatively reduced group and skeletal traction group). These 4 children had corrective osteotomy. Mild deformity was the inevitable one when it is treated conservatively. Limitation of elbow motion developed in 23 cases (32%) as a sequella. 5. Fracture healed mostly in three weeks after reduction and immobilization. Average hospital stay for conservatively treated patients was 17.2 days, whereas that for surgically treated patients was 5.8 days in average. 6. Early anatomical reduction by any means whether it is surgical or nonsurgical, proved to be only the methods which bring the satisfactory results, and minimize the sequellae.
Bandages ; Child ; Congenital Abnormalities ; Elbow ; Female ; Humans ; Humerus ; Immobilization ; Length of Stay ; Male ; Olecranon Process ; Osteotomy ; Skin ; Splints ; Traction ; Ulnar Neuropathies ; Wounds and Injuries