Hiroaki Sakata

Effects of intraarticular injection of halopredone diacetate on the articular cartilage of rabbit knees: A comparison with methylprednisolone acetate

Halopredone diacetate, which is a new synthetic corticosteroid drug showing local retention, and methylprednisolone acetate in common clinical use were injected into the knee joints of adult rabbits to compare the effects of the two drugs on the articular cartilage. The dosage of one injection was 1.75 mg (H-1 group) and 8.75 mg (H-5 group) for halopredone diacetate and 1.4 mg (M-1 group) and 7.0 mg (M-5 group) for methylprednisolone acetate. The drugs were injected into the right knee joint once a week, 12 times in total. One week after the last injection, the steroid crystals remaining in the knee joint were observed in all rabbits in the H-1 and H-5 groups. White deposits were seen locally on a part of the cartilage in all the rabbits in the H-1, H-5, and M-5 groups but not in the M-1 group. These white deposits were observed as cystic lesions by light microscopy and contained abundant hydroxyapatite. Other histologic findings in the articular cartilage included fissure, hypocellularity, and a decrease of proteoglycan in each group. However, no distinct difference was noted between the H-1 group and the M-1 group as regards the histological-histochemical grades of the cartilage on the medial tibial condyle or in the electron microscopic findings of the cartilage on the medial femoral condyle. The same was true for the H-5 and M-5 groups. These results show that repeated intraarticular injections of these two drugs cause severe cartilage lesions to the same degree, except for the intracartilaginous white deposits of rabbit knees.

Effect of bone marrow mononuclear phagocytes on the bone matrix-induced bone formation in rats

Experimental ulnar bone defects in rats were grafted with freshly isolated whole bone marrow cells; bone marrow mononuclear phagocytes (macrophages); or both types of marrow cell preparations in combination with demineralized bone matrix gelatin (BMG). In the absence of BMG, the osteogenic performance of the marrow cell preparations was superior to that of the macrophages. In the presence of BMG (composite grafts), their osteogenic potential was nearly identical and significantly improved the level of bone formation stimulated by implants of BMG alone. The results encourage speculation and further research on sequential activities of bone marrow monocyte-macrophage (osteoclast) lineages and marrow stromal (osteoprogenitor) cell in bone morphogenetic protein (BMP)-induced regeneration.

A Case of L2/3 Disc Hernia and L4 Dumbbell Tumor

We experienced a 70-year-old male case suffering L3 and L4 roots impairment due to L2/3 disc hernia, and L4 root impairment due to dumbbell tumor. He complained of severe low back pain, right femoral neuralgia, weakness, and urinary infection. MRI revealed two lesions; one was a tumor in the psoas muscle at the L3-L5 level originating from the L4 root ans the other was a downward sequestrated mass from the L3/4 disc. We operated two-stages from the anterior to posterior. The anterior tumor was histologically neurinoma and the sequestarted hernia mass impinged both the L3 and L4 roots.

Hemiarthroplasty for Hemodialysis Patients

The results of hemiarthroplasty for 18 hemodialysis patients are reported. There were 17 cases of femoral neck fractures and 1 case of aseptic necrosis of the femoral head. Subjects were followed-up for an average of 25 months. A retrospective analysis of the outcomes in 18 patients showed a return to the preinjury ambulatory status in 33per cent. 6 patients had died. In 2 patients loosening of the stem was observed.

Operative Results for Ligamentous Ossification in the Thoracic Spine

We surgically treated 20 cases of thoracic myelopathy caused by ossification of the yellow ligament (OYL) and combined OPLL. Subjects included 10 males and 10 females. The duration between the occurrence of symptoms and time of surgery ranged from 1 month to 2 years (average 8.3 months).The average age at surgery was 58 years. All patients had had laminectomy. We found difficulty in some cases in performing decompression of the ossified spinal lesions.

A Follow-up Study of Postoperative Cervical Laminoplasty

We studied 69 patients with cervical spondylotic myelopathy, and 33 patients with cervical ossification of the posterior longitudinal ligament with a mean age of 65.5 years and an average follow-up period of 4 years and 5 months. Clinical results were evaluated using the JOA score for cervical myelopathy and recovery rates using Hirabayashis method. The overall mean recovery rate was 58%. There was no significant difference between recovery rate and age, duration of symptoms or preoperative JOA score.Moreover, we radiographically investigated changes in cervical alignment and rate of enlargement, antero-posterior movement, and instability in 50 cases.