Magnetic resonance imaging observation of the conus medullaris

We examined the anatomical height and shape of the conus medullaris in 602 cases using magnetic resonance imaging. The peak of the distribution of the conus height was at the middle one-third of L1. The comparison of the conus level had no significant relationships with age or sex, but the juvenile group had more a caudal distribution of the conus level. The shape of the conus medullaris was classified into three types, and the type B was most frequently observed.

Rotational acetabular osteotomy for acetabular dysplasia

Between 1986 and 1990, we carried out 55 rotational acetabular osteotomies in 54 patients with acetabular dysplasia. Five hips were lost to follow-up. Of the 50 remaining, the degenerative changes were classified according to the criteria of Tönnis as grade 0 in 23, grade 1 in 16 and grade 2 in 11. The mean age of the three men and 46 women at the time of operation was 31.8 years (13 to 53). The mean follow-up was 137 months (120 to 174).

At the most recent follow-up, 48 patients had satisfactory relief from pain. There was a slight decrease in the range of movement, particularly of flexion, in 18 hips. Radiologically, all osteotomies had united satisfactorily. There was radiological evidence of improvement in degenerative changes in 13 hips (5 grade 1 and 8 grade 2). Ten deteriorated (5 grade 0, 3 grade 1, and 2 grade 2) and one required total hip arthroplasty ten years after osteotomy. The osteoarthritis in the two hips with an associated valgus osteotomy progressed. The changes in radiological indices such as the centre-edge angle, acetabular femoral head index, acetabular root obliquity and horizontal or vertical displacement of the femoral head showed no statistical difference (unpaired Student’s t-test) between the patients with radiological progression and those with and without improvement.

Rotational acetabular osteotomy for severely dysplastic acetabulum

The operative procedures chosen for arthrosis with severe acetabular dysplasia vary among orthopaedic surgeons. We operated on 250 hips using the rotational acetabular osteotomy (RAO) method of Ninomiya and Tagawa [8]. In this report, we describe the technique of RAO and the results of this procedure in patients with severely dysplastic hips. Among the 250 hips, there were 6 which were classified as Severin group V. In those hips, the CE angle was less than 0 degrees, and the femoral head showed superolateral subluxation. After acetabular osteotomy with straight and curved osteotomes, smooth inferolateral rotation could be done in all cases. At the latest follow-up symptoms were improved remarkably, especially pain. Radiographically, adequate coverage of the femoral head was achieved and joint congruence improved in all 6 hips.

Immunohistological study of intervertebral disc herniation of lumbar spine

In order to observe histological changes in the extruded and sequestrated intervertebral disc, we conducted pathological and immunological examinations of herniated disc materials taken at the time of discectomy. There were 49 disc materials (from 38 men and 10 women [aged 19 to 78 years; average, 36.6 years]). The herniation was classified into four types, based on the intraoperative observations: protrusion (P), subligamentous extrusion (SE), transligamentous extrusion (TE), and sequestration (S). There were 19 P type discs, 3 SE type, 10 TE type, and 17 S type. The surgical specimens were stained with hematoxylin-eosin, as well as immunohistological staining with the labelled streptavidin biotin method, using human T-cell, human B-cell, and human macrophage antibodies. Inflammatory-cell infiltration was observed at the border of the disc. These findings were present in 19 discs (70%) of the 27 discs of TE and S types (10 TE and 17 S types), but were not seen in the 22 discs of P and SE types (19 P and 3 SE types). Immunohistological staining of the area with inflammatory-cell infiltration revealed the presence of T cells and macrophages, which suggested that this cell infiltration originated from T cells and macrophages, and that the spontaneous resorption of the disc may have resulted from the phagocytic activities of these cells.

False aneurysm of the profunda femoris artery after total hip arthroplasty

A false aneurysm of the profunda femoris artery occurred after metal-on-metal total hip arthroplasty in 70-year-old woman. At 39 days after the operation, the wound suddenly opened, and a large hematoma was discharged. Eleven tornade coils were inserted into the base of the false aneurysm, and the bleeding was arrested. The prevention and management of this complication are discussed.

Revision surgery after triple-cup arthroplasty

Although various operative procedures have been applied for advanced or terminal osteoarthritis of the hip joints in relatively young patients, the long-term results are controversial. Since 1974, we have performed the triple-cup arthroplasty developed by Aoki in 110 patients who were comparatively young. The triple-cup assembly is composed of stainless-steel outer and inner cups between which a high density polyethylene cup is incorporated, so that there are basically four mobile surfaces, but the major movement is actually taking place between the outer cup and the plastic cup [8]. We have sometimes encountered migration of the cups, which caused hip joint pain and decreased the range of motion. Revision surgery was required for 25 hip joints in 21 patients (23%). The acetabulum was very thin in almost all cases, so that reaming of the cavity had to be restricted to the minimum possible. The femoral head in the cup was often covered with a layer of fibrous tissue. We could utilize the femoral head as a bone graft, even though the residual volume of bone varied in each case. The result of revision surgeries after the triple-cup arthroplasty was good clinically and radiographically at last follow-up.

Pulmonary thromboembolism after spinal instrumentation surgery

A 57-year-old woman was hospitalized because of gait disturbance and dysuria. Close examination revealed a cauda equina tumor at the level of L2 and L3. Tumor resection was performed, with posterolateral fusion and spinal instrumentation. On the eleventh day after the surgery, she experienced dyspnea and chest pain during standing and walking exercise. Pulmonary thromboembolism was diagnosed, based on: (1) blood gas analysis findings of hypoxemia and (2) defective images in both of the upper lobes on urgent pulmonary blood flow scintigram. Her clinical status improved with urgent thrombolytic therapy (with tisokinase and urokinase) and anticoagulation therapy (with heparin and warfarin), and her life was saved. When pulmonary thromboembolism occurs, early diagnosis by pulmonary blood flow scintigram and early thrombolytic and anticoagulative therapies are necessary. Special attention should be paid to symptoms of pulmonary thromboembolism in patients after spinal surgery.

Cytodiagnosis of malignant melanoma of soft tissue: report of a case with diagnosis by intraoperative cytology

BACKGROUND

Malignant melanoma of soft tissue (MMST) is a rare tumor and consists of < 1% of all soft tissue neoplasms. There are few reports on its cytodiagnosis.

CASE

A 14-year-old male attended the Department of Orthopedics, Juntendo University Urayasu Hospital, in August 1994 because of a painless tumor in the distal portion of the left thigh. Intraoperative imprint smear examination led to a diagnosis of malignant melanoma, and wide resection of the tumor, including the surrounding normal tissue, was performed. On cytologic examination, the background was relatively clean, with tumor cells distributing individually or in clusters. Under high magnification, the tumor cells were seen to contain a slightly enlarged, conspicuous nucleolus and large cell body. The cells varied in shape from polygonal to spindle shaped, with a few multinuclear giant cells. Melanin and glycogen were observed in varying degrees in the tumor cells.

CONCLUSION

MMST can be diagnosed easily if melanin is observed in the cytoplasm. Even in the absence of melanin, the tumor has relatively characteristic cytomorphology. Intraoperative cytology is useful for an accurate diagnosis of the tumor.

[Roentgenological follow-up of Lord-type cementless total hip arthroplasty]

The Lord-type cementless total hip arthroplasty has been employed for 240 hips involving 205 patients from 1979 to 1993. During this period, the following four types of prostheses were used incorporating the design changes suggested by Lord: Madréporique, Mark II, Polarisée and L. F. R. Postoperative roentgenological analysis was performed on 172 hips followed up for longer than one year. The Kaplan-Meier survivorship rating method was used for the assessment. With respect to the femoral component, intramedullary bone formation and cortical hypertrophy occurred mainly at zones 3, 4 and/or 5 (in 20%), while focal osteolysis occurred at zones 1 and 7 (2-6%). This was attributed to stress shielding in the long straight Lord stem. Radiolucent line around the femoral component (zone 1 through 7) was seen in 13 hips (7.6%), 8 of which showed definite subsidence and, consequently, 7 of these were revised. The five-and ten-year roentgenological survivorships of the Madréporique type stem were 100% and 92.8%, respectively. With respect to the acetabular component, a radiolucent line around the ring (zone I through III) was observed in 32 hips, 28 of which showed definite migration after two to nine-and-a-half years (average five years and nine months), for which 15 hips required revision. The five-and ten-year roentgenological survivorships of the acetabular component were 95.3% and 83.7%, respectively. The selection of a cemented rather than a cementless total hip arthroplasty has continued to be a subject of debate till the present. In our 14 year of experience using the Lord-type cementless prostheses, the Madréporique stem yielded satisfactory results, but the screw-in type ring acetabular component could be improved.