RESUMEN
BACKGROUND/OBJECTIVES: Knowledge of spinal cord injury (SCI) bone changes has been derived primarily through cross-sectional studies, many of which are controvertible. Longitudinal studies are sparse, and long-term longitudinal chronic studies are unavailable. The objective of this study was to provide a clearer perception of chronic longitudinal bone variations in people with complete SCI. METHODS: Bone status of 31 individuals with chronic, complete SCI was assessed twice using dual-energy xray absorptiometry at an average interval of 5.06 +/- 0.9 years. Because the sample of women was small (4), the primary analyses of change and comparisons of those with paraplegia vs tetraplegia were confined to the male participants. RESULTS: Spine Z-scores showed a significant increase (P < 0.0001). The average Z-scores, initial and followup, were within the normal range. Hip Z-scores also showed a significant increase (P < 0.0001), and hip bone mineral density (BMD) increased in 48% of the participants. Knee BMD and lower extremity total bone mineral showed significant decreases (P < 0.003 and P < 0.02, respectively), but increases were seen in 33% and 26% at the respective sites. Individuals with tetraplegia had significantly lower values across all regions (P < 0.0001), and changes were significantly different compared with paraplegia (P < 0.0001). Bone values and changes in men vs women, despite the small sample of women, showed highly significant differences (P < 0.003-0.002). CONCLUSION: Chronic effects of complete SCI do not exclusively result in continued loss of BMD or a static state of lowered BMD; gain in BMD may occur. The nature and magnitude of the effects of complete SCI on BMD vary by site, with sex and level of injury, which has implications for treatment and its assessment.
Asunto(s)
Densidad Ósea , Huesos , Traumatismos de la Médula Espinal/patología , Traumatismos de la Médula Espinal/fisiopatología , Absorciometría de Fotón/métodos , Adulto , Huesos/diagnóstico por imagen , Estudios Transversales , Femenino , Cadera/patología , Humanos , Rodilla/patología , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Factores Sexuales , Traumatismos de la Médula Espinal/metabolismo , Columna Vertebral/patologíaRESUMEN
BACKGROUND: The objective of this study was to determine modifiable and nonmodifiable risk factors for bone loss at the knee in individuals with spinal cord injury (SCI) by examining known risk factors for osteoporosis in the general population and additional, unique nonmodifiable SCI elements including age at injury onset, injury duration, and extent of neurologic injury (level and completeness). METHODS: Risk factors were examined by logistic regression in 152 individuals with chronic SCI. Knees were classified as osteoporotic based on whether bone mineral density (BMD) of the knee as assessed by dual-energy x-ray absorptiometry fell within the 95% confidence interval of the BMD of the knee of individuals who had experienced fractures at the knee. RESULTS: Accuracy for predicted membership in the osteoporotic group and nonosteoporotic group were 79.22% and 69.33%, respectively. Of all variables included in the analysis, 3 had a significant effect on predicted group membership: completeness of injury (P < 0.0001), body mass index (BMI) (P = 0.0035), and age (P = 0.0394). Individuals with complete injuries were 6.17 times (617%) more likely to have BMD of the knee low enough to place them in the osteoporotic category. The odds ratio for BMI indicated that every unit increase in BMI lowered the odds of being in the osteoporotic group by 11.29%. The odds ratio for age indicated that every 1-year increase in age increased the odds of being in the osteoporotic group by 3.54%. No other modifiable or nonmodifiable risk factors were significant predictors. CONCLUSION: Completeness of injury dictates and overrides most modifiable and nonmodifiable risk factors for bone loss at the knee leading to pathologic fractures in SCI. SCI osteoporosis may be classified more appropriately as neurogenic in origin.
Asunto(s)
Densidad Ósea , Fémur/metabolismo , Osteoporosis/etiología , Traumatismos de la Médula Espinal/complicaciones , Tibia/metabolismo , Absorciometría de Fotón , Adulto , Factores de Edad , Anciano , Índice de Masa Corporal , Femenino , Fémur/diagnóstico por imagen , Fracturas Óseas/etiología , Humanos , Masculino , Persona de Mediana Edad , Factores de Riesgo , Tibia/diagnóstico por imagenRESUMEN
BACKGROUND/OBJECTIVE: The objective of this study was to document acute bone loss at the os calcis and compare it with bone loss at the knee following spinal cord injury (SCI) as a potential proxy for bone loss in individuals with SCI. METHODS: Bone mineral density (BMD) was measured by dual energy x-ray absorptiometry (DEXA) at the knee and os calcis, which also was assessed by ultrasound in 6 individuals--5 with complete SCI and 1 with incomplete SCI--at means of 33.5 and 523 days following injury. RESULTS: Bone mineral was progressively greater as measured from proximal to distal sites. The net average BMD of the knee declined 24% (P = 0.017). The distal femur lost 27% (P = 0.038) and the proximal tibia lost 32% (P = 0.015), whereas the os calcis lost 38% (P = 0.001) as measured by DEXA and 49% (P < 0.001) as estimated from ultrasound. The mean loss of 24% at the knee was significantly different from the loss percentages at the os calcis as measured by both techniques: DEXA (P = 0.036) and ultrasound (P = 0.043). Differences between annualized loss rates at the knee and the os calcis measured by both techniques also were significant: DEXA (P = 0.032) vs ultrasound (P = 0.038). However, annualized loss rates demonstrated the same trend for differential loss at the sites examined in the 5 individuals with complete injuries but not for the 1 participant with an incomplete injury. The loss rates were similar for the complete and incomplete participants at the os calcis, but not at the knee. CONCLUSION: The BMD of the os calcis declined 38% by DEXA and 49% by ultrasound compared with 24% at the knee when measured 1 to 1.5 years after injury. BMD of the os calcis and distal femur measured by DEXA in persons with complete SCI were highly correlated (r = 0.84, P < 0.0001).
Asunto(s)
Densidad Ósea , Fémur/metabolismo , Osteoporosis/etiología , Traumatismos de la Médula Espinal/complicaciones , Huesos Tarsianos/metabolismo , Tibia/metabolismo , Absorciometría de Fotón , Adulto , Femenino , Fémur/diagnóstico por imagen , Estudios de Seguimiento , Humanos , Masculino , Huesos Tarsianos/diagnóstico por imagen , Tibia/diagnóstico por imagen , Factores de Tiempo , UltrasonografíaRESUMEN
BACKGROUND: Within the past decade several reports have been published concerning heterotopic ossification (HO) in adult respiratory distress syndrome patients subjected to prolonged mechanical ventilation. The knee has been the most common site of involvement, which tends to differentiate this entity of HO from those previously described. METHOD: Case report and literature review. FINDINGS: HO associated with prolonged intubation differs in clinical presentation from HO seen in spinal cord injury (SCI) and other trauma. Use of neuromuscular blockade does not appear to explain this risk. An unidentified humoral response mechanism may underlie the development of HO in these cases. Certain individuals may be genetically predisposed to develop HO. CONCLUSION: Increased awareness of this relatively new entity may assist early diagnosis, medical treatment, and eventually direct rehabilitation. Investigation of the pathogenesis of different types of HO may provide clues to the prevention and treatment of HO in individuals with SCI and other central nervous system trauma.