Decreased bone mineral density in neurofibromatosis-1 patients with spinal deformities.

A cross-sectional study was carried out to obtain data on the bone mineral density status of a group of neurofibromatosis-1 patients with spinal deformities, and to search for possible accompanying changes in the bone mineral turnover. Neurofibromatosis-1 is a heredofamiliar disorder that is associated with a variety of skeletal anomalies (mostly spinal deformities) in 10-50% of patients. Intraoperatively, a poor vertebral bone quality has been observed. Efforts have been made to identify factors preventing curve progression, to optimize operational planning and to explain the pathomechanism. As part of the preoperative evaluation, dual-energy X-ray absorptiometry was used to assess the bone mineral density of the lumbar spine in 12 patients with neurofibromatosis-1, supplemented by laboratory blood/urine investigations. A significant decrease in bone mineral density of the lumbar spine was measured. An inverse relation was suggested between the severity of scoliosis and the lumbar spine Z-scores. No pivotal alterations were identified in the laboratory measurements. The bony tissue abnormality observed intraoperatively in neurofibromatosis-1 patients may be described as a diminution of the axial bone mineral density. The biochemical parameters do not support the presence of hyperparathyroidism, renal disorders or other associated diseases influencing the bone mineral turnover. The evaluation of bone mineral density in the course of the preoperative planning is proposed in neurofibromatosis-1; the exact background and the role of a possible osteoporosis in the prognosis remain to be elucidated.

[Decreased bone mineral density as a risk factor in the development of spinal deformities in neurofibromatosis]. / Csökkent csontdenzitás, mint lehetséges tényezó a neurofibromatosist kíséró gerincdeformitások kialakulásában.

Neurofibromatosis-1 is a here-do-familiar disorder that is associated with a variety of skeletal anomalies, mostly with spinal deformities in 10-50% of the patients. Intraoperatively, a poor vertebral bone quality has been observed. Efforts have been made to identify factors preventing curve progression, to optimize operational planning and to explain the pathomechanism. As part of the preoperative evaluation, the authors used a dual X-ray absorptiometry to assess the bone mineral density of the lumbar spine in 12 non operated patients with neurofibromatosis-1, supplemented by laboratory blood/urine investigations. A significant decrease in bone mineral density of lumbar spine was measured. An inverse relation was suggested between the severity of scoliosis and the lumbar spine Z-scores. No pivotal alterations were identified in the laboratory measurements. The bony tissue abnormality observed intraoperatively in neurofibromatosis-1 patients may be described as a diminution of the axial bone mineral density. The evaluation of bone mineral density in the course of the preoperative planning is proposed in neurofibromatosis-1.

Experimental stimulation of osteogenesis induced by bone matrix.

Bone gaps in 20 rabbits were filled with decalcified homologous bone. Direct currents, intravenous calcium, and anabolic steroids were administered for stimulation of osteogenesis. The shape and microscopic structure of the newly formed bone, together with the velocity of the osteogenesis, were investigated. Results were assessed by microscopic and radiographic analyses. In the group of calcium posttreatment, irregular shape and callosities were characteristic. Anabolic steroids failed to improve consolidation significantly; best results were seen after electrical stimulation of the grafted areas. In the group with electrical stimulation, fair shape, together with a more regular microscopic structure of the newly formed bone, were characteristic 4 weeks after surgery. Ungrafted gaps, together with defects filled with undecalcified cortical bone, failed to heal within the examined period of time.