Unidirectional porous beta-tricalcium phosphate as a potential bone regeneration material for infectious bony cavity without debridement in pyogenic spondylitis.

An 81-year-old man was initially diagnosed with T11 osteoporotic vertebral fracture. The fractured vertebral body was filled with unidirectional porous beta-tricalcium phosphate (ß-TCP) granules, and posterior spinal fixation was conducted using percutaneous pedicle screws. However, the pain did not improve, the inflammatory response increased, and bone destructive changes extended to T10. The correct diagnosis was pyogenic spondylitis with concomitant T11 fragility vertebral fracture. Revision surgery was conducted 2 weeks after the initial surgery, the T10 and T11 pedicle screws were removed, and refixation was conducted. After the revision surgery, the pain improved and mobilization proceeded. The infection was suppressed by the administration of sensitive antibiotics. One month after surgery, a lateral bone bridge appeared at the T10/11 intervertebral level. This increased in size over time, and synostosis was achieved at 6 months. Resorption of the unidirectional porous ß-TCP granules was observed over time and partial replacement with autologous bone was evident from 6 months after the revision surgery. Two years and 6 months after the revision surgery, although there were some residual ß-TCP and bony defect in the center of the vertebral body, the bilateral walls have well regenerated. This suggested that given an environment of sensitive antibiotic administration and restricted local instability, unidirectional porous ß-TCP implanted into an infected vertebral body may function as a resorbable bone regeneration scaffold without impeding infection control even without debridement of the infected bony cavity.

The Decalcification of Cervicothoracic Spinal Metastasis of Breast Cancer Due to Discontinuation of Denosumab: A Case Report.

Breast cancers frequently metastasize to bone. Several guidelines recommend denosumab to control metastasis. In the current case, denosumab allowed the calcification of cervicothoracic spinal metastases following bone decalcification by breast cancer. Six years after administration, denosumab was discontinued and the metastatic lesions became decalcified, but recalcification occurred after re-administration of denosumab. There were no reports of serious decalcification after discontinuation of denosumab. The patient was a 71-year-old woman who was unable to walk independently because of a fracture of the seventh cervical vertebra and severe spinal cord compression. After immobilization with a halo vest, posterior fixation was performed. Examination of the pathology of the breast and cervical spine revealed ductal carcinoma of the breast. After docetaxel for four months, tegafur-gimeracil-oteracil potassium (TS-1) was administered and monthly denosumab was initiated. CT showed postoperative recalcification of the cervicothoracic spine, and MRI revealed spinal cord decompression. The first occurrence of medication-related osteonecrosis of the jaw (MRONJ) occurred five years after cervicothoracic spinal surgery and the second occurrence of MRONJ occurred after six years. Denosumab was discontinued and TS-1 was resumed four months after discontinuation. Fourteen months after discontinuation of denosumab, the patient felt muscle weakness in the right upper extremity and numbness in both hands. CT showed cervicothoracic spine decalcification and MRI showed spinal cord compression. As there were no signs of recurrence in the primary lesion around the left breast, TS-1 was continued and denosumab was resumed. Three months after the re-administration of denosumab, CT showed recalcification and recovery of upper extremity muscle strength, and MRI revealed improvement in spinal cord compression.