A new mechanism of injury in ankylosing spondylitis: non-traumatic hyperextension causing atlantoaxial subluxation

Ankylosing spondylitis (AS) is a progressive multisystem chronic inflammatory disorder. The hallmark of this pathological process is a progressive fusion of the zygapophyseal joints and disc spaces of the axial skeleton, leading to a rigid kyphotic deformity and positive sagittal balance. The ankylosed spine is unable to accommodate normal mechanical forces, rendering it brittle and susceptible to injury. Traumatic hyperextension injury of the cervical spine leading to atlantoaxial subluxation (AAS) in AS patients can often be fatal. We report a non-traumatic mechanism of injury in AS progressing to AAS attributable to persistent hyperextension, which resulted in fatal migration of C2 through the foramen magnum.

The prevalence and radiological findings in 1347 elderly patients with scoliosis

In order to determine the epidemiology of adult scoliosis in the elderly and to analyse the radiological parameters and symptoms related to adult scoliosis, we carried out a prospective cross-sectional radiological study on 1347 adult volunteers. There were 615 men and 732 women with a mean age of 73.3 years (60 to 94), and a mean Cobb angle of 7.55° (sd 5.95).

In our study, 478 subjects met the definition of scoliosis (Cobb angle ≥10°) showing a prevalence of 35.5%. There was a significant difference in the epidemiological distribution and prevalence between the age and gender groups. The older adults showed a larger prevalence and more severe scoliosis, more prominent in women (p = 0.004). Women were more affected by adult scoliosis and showed more linear correlation with age (p < 0.001). Symptoms were more severe in those with scoliosis than in the normal group, but were similar between the mild, moderate and severe scoliosis groups (p = 0.224) and between men and women (p = 0.231).

Adult scoliosis showed a significant relationship with lateral listhesis, vertebral rotation, lumbar hypolordosis, sagittal imbalance and a high level of the L4–5 disc (p < 0.0001, p < 0.0001, p = 0.002, p = 0.002, p < 0.0001 respectively). Lateral listhesis, lumbar hypolordosis and sagittal imbalance were related to symptoms (p < 0.0001, p = 0.001, p < 0.0001 respectively).

Femoral lengthening in achondroplasia: magnitude of lengthening in relation to patterns of callus, stiffness of adjacent joints and fracture

Extensive limb lengthening may be indicated in achondroplastic patients who wish to achieve a height within the normal range for their population. However, increasing the magnitude of lengthening is associated with further complications particularly adjacent joint stiffness and fractures. We studied the relationship between the magnitude of femoral lengthening and callus pattern, adjacent joint stiffness and fracture of the regenerate bone in 40 femoral lengthenings in 20 achondroplastic patients. They were divided into two groups; group A had lengthening of less than 50% and group B of more than 50% of their initial femoral length. The patterns of radiological callus formation were classified according to shape, type and features. The incidence of callus features, knee stiffness and regenerate bone fracture were analysed in the two groups. Group B was associated with an increased incidence of concave, lateral and central callus shapes, adjacent joint and stiffness and fracture. Statistically, the incidence of stiffness in adjacent joints and regenerate bone fracture was significantly associated with the magnitude of lengthening. We suggest that careful radiological assessment of the patterns of callus formation is a useful method for the evaluation and monitoring of regenerate bone.

Grade 4 spondylolisthesis of the L5 vertebra associated with dural ectasia in neurofibromatosis

Spondylolisthesis associated with neurofibromatosis is rare, and only 12 cases have been reported so far. However, only one report of grade 4 spondylolisthesis with neurofibromatosis has been reported in the literature. A 15-year-old boy with neurofibromatosis was admitted for back pain and neurological claudication. Radiograph showed grade 4 spondylolisthesis of the L5 vertebra with scalloping of the L4-L5 vertebrae. L4-L5 laminectomy, reduction, L3-S1 posterior instrumentation and fusion were performed. The reduction of the spondylisthesis was done entirely from the posterior approach using pedicle screws. Radiography at four months showed a broken S1 screw with a loss of reduction. The patient was re-operated on, to provide additional stability with pelvic fixation. He was pain-free with a good fusion at the two-year follow-up. Adequate posterior stabilisation with fusion gives good results in grade 4 spondylolisthesis associated with neurofibromatosis and dural ectasia.

Reconstruction of iliac crest with rib to prevent donor site complications: A prospective study of 26 cases

BACKGROUND

The tricortical bone graft from the iliac crest are used to reconstruct the post corpectomy spinal defects. The donor iliac area defect is large and may give rise to pain at donor site, instability of pelvis, fracture of ilium, donor site muscle herniation or abdominal content herniation. Rib removed during thoracotomy was used by us to reconstruct the iliac crest defect.

MATERIALS AND METHODS

Twenty-six patients who underwent thoracotomy for dorsal spine corpectomy or curettage for various spinal pathologies from June 2002 to May 2004 were included in the study. After adequate decompression the spine was reconstructed by tricortical bone graft from iliac crest and reconstruction of the iliac crest was done with the rib removed for exposure during thoracotomy.

RESULTS

The mean follow up was 15 months. All patients had good graft incorporation which was evaluated on the basis of local tenderness and radiographs. One patient had graft displacement.

CONCLUSION

The reconstruction of iliac crest by rib is a simple and effective procedure to prevent donor site complications.

Reduced alveolar macrophage production of tumor necrosis factor during sepsis in mice and men

BACKGROUND AND METHODS

Tumor necrosis factor (TNF) has been implicated as a major humoral mediator of sepsis and endotoxin shock. TNF is secreted by cells of the reticuloendothelial system, including alveolar macrophages. Alveolar macrophage TNF production has been postulated to play a pathogenetic role in the development of adult respiratory distress syndrome (ARDS) in sepsis. To evaluate alveolar macrophage production of TNF during sepsis and endotoxin shock, we studied the effects of sepsis and/or in vivo lipopolysaccharide on the in vitro production of TNF by pulmonary alveolar macrophages. Human pulmonary alveolar macrophages were obtained by bronchoalveolar lavage from six septic and five nonseptic patients, cultured in the presence or absence of lipopolysaccharide (1 ng/mL), and assayed for TNF activity in a bioassay using fibroblast lysis. A murine model of sepsis was also utilized to study pulmonary alveolar macrophage TNF production under more controlled conditions. Normal mice were given ip injections of either lipopolysaccharide or saline. After 2 hrs, pulmonary alveolar macrophages were obtained and cultured in saline or various concentrations of lipopolysaccharide (0.001 to 10 micrograms/mL).

RESULTS

There was no difference in baseline TNF activity, expressed as per cent lysis at 1:10 dilution, between pulmonary alveolar macrophages from control and septic patients (35.7 +/- 5.5% vs. 24.4 +/- 9.3%, respectively) (p greater than .05). However, when stimulated with lipopolysaccharide in vitro, the pulmonary alveolar macrophages from nonseptic patients produced significantly (p less than .01) more TNF (82.8 +/- 3.6%) than did pulmonary alveolar macrophages from patients with the septic syndrome (35.2 +/- 3.8%). Similar findings were obtained using the murine sepsis model. The baseline TNF activity in pulmonary alveolar macrophages from control mice was 22.9 +/- 7.0% (mean +/- SEM) and from lipopolysaccharide-injected mice was 26.8 +/- 3.3% (p greater than .05). Stimulation with 1 ng/mL lipopolysaccharide in vitro produced an increase in TNF activity in both groups, but the increase was greater in the control mice (68.1 +/- 5.7%) than in the lipopolysaccharide-injected mice (47.5 +/- 5.3%) (p less than .01). When the murine pulmonary alveolar macrophages were stimulated with higher concentrations of lipopolysaccharide (0.1 to 10 micrograms/mL), pulmonary alveolar macrophages from lipopolysaccharide-injected mice produced less than 25.5% of the TNF produced by pulmonary alveolar macrophages from control mice.

CONCLUSIONS

These studies indicate that sepsis and endotoxin injection result in a rapid decrease in the ability of pulmonary alveolar macrophages from both humans and mice to produce and secrete TNF in response to lipopolysaccharide. We speculate that a downregulation of TNF production or of macrophage responsiveness to lipopolysaccharide has occurred. These results suggest that sustained TNF production by macrophages is not required for lung injury in sepsis.