Kenji Takegami

New ferromagnetic bone cement for local hyperthermia.

We have developed a ferromagnetic bone cement as a thermoseed to generate heat by hysteresis loss under an alternate magnetic field. This material resembles bioactive bone cement in composition, with a portion of the bioactive glass ceramic component replaced by magnetite (Fe3O4) powder. The temperature of this thermoseed rises in proportion to the weight ratio of magnetite powder, the volume of the thermoseed, and the intensity of the magnetic field. The heat-generating ability of this thermoseed implanted into rabbit and human cadaver tibiae was investigated by applying a magnetic field with a maximum of 300 Oe and 100 kHz. In this system, it is very easy to increase the temperature of the thermoseed in bone beyond 50 degrees C by adjusting the above-mentioned control factors. When the temperature of the thermoseed in rabbit tibiae was maintained at 50 to 60 degrees C, the temperature at the interface between the bone and muscle (cortical surface) surrounding the material rose to 43 to 45 degrees C; but at a 10-mm distance from the thermoseed in the medullary canal, the temperature did not exceed 40 degrees C. These results demonstrate that ferromagnetic bone cement may be applicable for the hyperthermic treatment of bone tumors.

A novel hyperthermia treatment for bone metastases using magnetic materials.

Patients with bone metastases in the extremities sometimes require surgical intervention to prevent deterioration of quality of life due to a pathological fracture. The use of localized radiotherapy combined with surgical reinforcement has been a gold standard for the treatment of bone metastases. However, radiotherapy sometimes induces soft tissue damage, including muscle induration and joint contracture. Moreover, cancer cells are not always radiosensitive. Hyperthermia has been studied since the 1940s using an experimental animal model to treat various types of advanced cancer, and studies have now reached the stage of clinical application, especially in conjunction with radiotherapy or chemotherapy. Nevertheless, bone metastases have several special properties which discourage oncologists from developing hyperthermic therapeutic strategies. First, the bone is located deep in the body, and has low thermal conductivity due to the thickness of cortical bone and the highly vascularized medulla. To address these issues, we developed new hyperthermic strategies which generate heat using magnetic materials under an alternating electromagnetic field, and started clinical application of this treatment modality. The purpose of this review is to summarize the latest studies on hyperthermic treatment in the field of musculoskeletal tumors, and to introduce the treatment strategy employing our novel hyperthermia approach.

Mixture ratios of local bone to artificial bone in lumbar posterolateral fusion.

There have been no reports on the effects of the mixture ratio of local bone graft to artificial bone on the outcome of intervertebral bone fusion. The purpose of this study was to determine whether the mixture ratio of local bone removed from laminae and spinous processes to apatite- and wollastonite-containing glass ceramic (AWGC) granules affected fusion rates in spinal fusion. Posterolateral lumbar fusion at two levels without spinal instrumentation was performed in 35 patients who were diagnosed with lumbar spinal canal stenosis. The patients were randomly divided into three groups, each of which received a different mixture ratio of local bone to AWGC granules: 2:1, 1:1, and 1:2. The total mass of grafted bone was 20 g in all three groups. The fusion rate was approximately 80% in all three groups. Our results indicate that lumbar posterolateral fusion can be successfully achieved even when the mixture ratio of local bone graft to AWGC granules is 1:2.

Change of barometric pressure influences low back pain in patients with vacuum phenomenon within lumbar intervertebral disc.

The present study investigates whether changes in barometric pressure influence low back pain in patients with vacuum phenomenon within lumbar intervertebral discs. Twenty-four patients with low back pain were examined: 12 with vacuum phenomenon within the intervertebral discs (VP [+] group) and 12 without the vacuum phenomenon (VP [−] group). All patients consented to an evaluation of low back pain in a hyperbaric oxygen chamber. In the VP (+) group, low back pain became more severe in one patient when atmospheric pressure was elevated, and in eight patients when atmospheric pressure was decreased. In the VP (−) group, two patients experienced more severe low back pain when atmospheric pressure was decreased. Our study demonstrated that low back pain might be aggravated by atmosphere depression in patients with lumbar disease associated with the vacuum phenomenon.

Length of the ribs in patients with idiopathic scoliosis

Abstract. There have been few reports of actual measurements of rib length in patients with idiopathic scoliosis. We measured the lengths of the 7th to 12th ribs in 28 patients with idiopathic scoliosis with right convex single thoracic curve. The measurements were performed by the multi-projection volume reconstruction method of computed tomography. A significant difference between the left and right side length (laterality) was observed in the 11th and 12th ribs. Laterality was not observed in the 7th, 8th, 9th, and 10th ribs. In this study, it appeared inadequate to conclude that the laterality of rib length caused the scoliosis. Since the 11th and 12th ribs were floating ribs, we speculated that, on the contrary, the scoliosis affected the laterality of the rib length.

Spinal neurocutaneous melanosis without cutaneous nevi.

Study Design. A case report of spinal neurocutaneous melanosis without cutaneous nevi. Objective. To show a case and review the epidemiology, diagnosis and treatment of neurocutaneous melanosis without cutaneous nevi. Summary of Background Data. Neurocutaneous melanosis is a rare congenital syndrome consisting of benign or malignant melanocytic tumors of the central nervous system and cutaneous nevi. Symptomatic neurocutaneous melanosis has extremely poor prognosis, even in the absence of malignancy. Because leptomeningeal lesions of the neurocutaneous melanosis usually undergo malignant transformation, the life expectancy of almost all patients with malignant transformation is <1 year. In general, patients are treated with palliative therapy, such as shunt placement to reduce intracranial pressure or tumor resection to reduce compression of the brain or spine. Methods. A 29-year-old man presented with marked hypesthesia and spastic gait. No skin abnormalities were evident. Magnetic resonance imaging (MRI) of the spine revealed intradural tumor at the T5 level. Computed tomography myelography showed intradural extramedullary tumor. Because symptoms progressed, he underwent surgery to decompress the spinal cord. After the pigmented dura was opened, a pigmented tumor was resected. Results. Histologically, the pigmented tumor represented low grade. The pigmented dura and bone comprised melanin-bearing cells without tumor cells. Meningeal melanocytoma with leptomeningeal melanosis in the absence of cutaneous nevi was diagnosed. Neurologic symptoms recovered immediately after surgery. No evidence of local recurrence has been seen after 3 years. Conclusion. This patient displayed spinal meningeal melanocytoma and leptomeningeal melanosis without cutaneous nevi. The diagnosis in this case was speculated to represent a forme fruste of neurocutaneous melanosis.

Intraosseous lipoma of the third lumbar spine: a case report

IntroductionIntraosseous lipoma is a benign bone tumor, and the tumor occurs more frequently in the lower extremities. We present a very rare case of intraosseous lipoma occurring in the lumbar vertebral arch and spinous process.Case presentationA 54-year-old Japanese man presented with a three-month history of lumbar pain. Magnetic resonance imaging of the L3 vertebral arch and spinous process revealed high intensity on T1- and T2-weighted imaging, and it was suppressed on fat-suppression imaging and no enhancement showed on gadolinium contrast-enhanced imaging. Computed tomography imaging revealed an osteolytic change accompanied by marginal osteosclerosis in his third lumbar vertebral arch and spinous process, as well as a thinned and bulging bone cortex. An analgesic had been administered prior to his visit, but low back pain had persisted, so we performed curettage and filled the defect with hydroxyapatite bone. His low back pain was improved immediately after surgery, and no recurrence of tumor has been observed on computed tomography imaging as of three years postoperatively.ConclusionsSymptomatic intraosseous lipoma of spine is very rare, but the patient may be surgically well-treated by curettage and reconstruction of the benign tumor.