Heparin versus danaproid for prevention of venous thromboembolism after hip surgery

PURPOSE

To compare the prevalence of deep vein thrombosis (DVT), pulmonary thromboembolism (PTE), and bleeding complications in patients receiving heparin or danaproid after hemiarthroplasty or osteosynthesis for hip fractures.

METHODS

37 men and 138 women aged 47 to 100 (mean, 80) years underwent either hemiarthroplasty or osteosynthesis for hip fractures; 5 patients with dementia were excluded. All patients received preoperative elastic stocking and postoperative intermittent pneumatic compression. They were divided into 3 groups based on their admission period: controls (n=71), unfractionated heparin (n=44), and danaproid sodium (n=55). Drugs were administered from postoperative day 1 to 7. At day 7, all patients undertook radioisotope venography of the legs and lung perfusion scintigraphy.

RESULTS

In the control, heparin, and danaproid groups respectively, the DVT rates were 31%, 9.1%, and 5.5%, and the PTE rates were 5.6%, 4.5%, and 1.8%. Only the DVT rate in the control group was significantly higher than that in the heparin and danaproid groups. In the heparin group, one patient had gastrointestinal bleeding, 5 developed wound haematomas, and one had leakage from the drain site for 2 weeks.

CONCLUSION

Danaproid sodium appeared more effective and safer than heparin, with no bleeding complications occurred.

Usefulness of stress-loading test for ankle brachial index using an originally developed exercise device to detect peripheral arterial disease

AIM

In the detection of peripheral arterial disease (PAD), the post-exercise ankle brachial index (ABI) using a treadmill is useful although time consuming. We developed a stress-loading device that induces fatigue in the calf muscles while remaining in the supine position, which is designed to reduce delay between completion of the exercise and measurement and to reduce the potential for cardiac and cerebrovascular accident in at-risk persons.

METHODS

Using our original device, we measured post-stress-loading ABI in 536 patients (1,072 legs) with lower extremity symptoms such as intermittent claudication. ABI was measured at rest and after stress loading by VaSera.

RESULTS

The sensitivity and specificity of resting ABI using a cutoff of 0.9 was 74.8% and 99.4%, respectively, and of post-stress-loading ABI was 85.0% and 99.6%, respectively. The absolute and percent decrease of ABI after stress loading was 0.09+/-0.10 and 13.6+/-13.9%, respectively, in the PAD group and 0.04+/-0.05 and 3.2+/-4.0%, respectively, in the non-PAD group, a statistically significant difference (P<0.01).

CONCLUSIONS

Our originally developed stress-loading device for measurement of ABI under load simplifies the test procedures and increases the testing precision to a level higher than that of resting ABI and to that comparable to the conventional treadmill method.

The effect of hydrostatic pressure on intervertebral disc metabolism

STUDY DESIGN

By the use of pressure vessels, hydrostatic pressure was applied to intervertebral disc cells cultured in an alginate.

OBJECTIVE

To test the hypothesis that hydrostatic pressure directly affects the synthesis of collagen and proteoglycan by the intervertebral disc cells.

SUMMARY OF BACKGROUND DATA

The influence of compression (both hydrostatic and mechanical) on chondrocyte metabolism was examined in a number of earlier studies. However, in most of these studies, articular cartilage, not intervertebral disc, was used, and in none of these was hydrostatic pressure applied to intervertebral disc cells cultured in alginate.

METHODS

Fresh cells were harvested from the lumbar intervertebral discs of dogs. Before their suspension in an alginate gel system, the cells were plated and expanded until they reached confluence. Then, by use of the alginate gel system, the cells were exposed (for up to 9 days) to specific values of hydrostatic pressure inside two stainless steel pressure vessels. One vessel was kept at 1 MPa and the other at atmospheric pressure. The effects of 1 MPa were compared against atmospheric pressure by measuring the incorporation of [3H]-proline and [35S]-sulfate into collagen and proteoglycans, respectively, for the anulus cells and nucleus cells separately, and by determining whether this incorporation was reflected by changes in the levels of mRNA for aggrecan and Types I and II collagen.

RESULTS

Comparisons with atmospheric pressure yielded the following findings: 1) In the incorporation studies, the nucleus and anulus cells exhibited a differential response to a hydrostatic pressure of 1 MPa. Collagen and proteoglycan syntheses were stimulated in the nucleus cells and inhibited in the anulus cells. 2) There was no significant increase in cell proliferation, as measured by DNA content, at 1 MPa for either the anulus or nucleus cells. 3) The mRNA levels of collagen (Col 1A1 and Col 2A1) and aggrecan increased at 1 MPa in both the nucleus and anulus cells.

CONCLUSIONS

Hydrostatic pressure directly affects the synthesis of collagen and proteoglycan by the intervertebral disc cells.

The effect of compressive force applied to the intervertebral disc in vivo. A study of proteoglycans and collagen

STUDY DESIGN

Coil springs were stretched and attached to produce a compressive force across the lumbar intervertebral discs of dogs for up to 27 weeks.

OBJECTIVE

To test the hypothesis that a high compressive force applied over a period of time affects the production of proteoglycans and collagen by the intervertebral disc cells.

SUMMARY OF BACKGROUND DATA

It is a commonly held belief that high forces applied to the intervertebral disc, and to joints in general, play a role in causing degeneration.

METHODS

Pairs of stainless steel coil springs were stretched and attached to produce a compressive force across the lumbar intervertebral discs (L1-L2 and L3-L4) of 16 dogs. Dogs were killed between 13 and 27 weeks after the springs were attached. The discs (L1-L2 and L3-L4) were excised and assessed using immunohistochemical analyses and enzyme-linked immunosorbent assay; T13-L1 and L4-L5 were used as controls.

RESULTS

The main result relates to a group effect in the six dogs, assessed using enzyme-linked immunosorbent assay, that were generally at the highest values of force for the greatest number of weeks. For the nucleus, but not the anulus, Spearman rank correlations revealed a strong correlation between increases in force and force-weeks (force multiplied by number of weeks) and increases in collagen type I accompanied by decreases in proteoglycans, chondroitin sulfate, and collagen type II for both experimental discs (L1-L2 and L3-L4), as compared with corresponding values in the controls (T13-L1 and L4-L5). In other words, as either the force or the force-weeks increased, the effect on the nucleus became greater.

CONCLUSION

A high compressive force applied to the disc over a period of time initiates changes in proteoglycans and collagen.

Vascularization of the fusion mass in a posterolateral intertransverse process fusion

STUDY DESIGN

A previously characterized rabbit model was used to study vascularization of the fusion mass in a posterolateral intertransverse process fusion.

OBJECTIVES

To determine the interosseus origin of the new blood vessels in a posterolateral intertransverse process fusion mass and to test the hypothesis that bone incorporation and the extent of vascularization are closely related.

SUMMARY OF BACKGROUND DATA

It has been reported that vascularization is essential for bone graft incorporation. There are, however, few reports dealing with vascularization of the spinal arthrodesis.

METHODS

Thirty-one adult New Zealand White rabbits underwent bilateral intertransverse process fusion, using autogenous iliac crest bone graft. The rabbits were killed at 3 weeks (n = 6) and 6 weeks (n = 25) after surgery, and colored silicone was injected to fix the vasculature. A semiautomated image analysis system was used to assess the percentage of the area of vascularization in the fusion mass and the transverse processes.

RESULTS

The major interosseus blood supply for vascularization of the autogenous bone graft came from upper and lower transverse processes. There were three types of fusion mass observed at 6 weeks after surgery: solid type, solid type with cartilaginous cleft, and nonunion type. There was significantly less vascularization of the fusion mass and of the transverse processes in the nonunion type compared with that in the solid type and with that in the cartilaginous cleft type.

CONCLUSIONS

There is a close correlation between bone incorporation and the extent of vascularization in a posterolateral intertransverse process fusion.

Guidelines to decortication in posterolateral spine fusion

Despite the development of innovative approaches and the general success that has been achieved with spinal fusion, the rate of nonunion in some studies has been reported as high as 35%. Decortication has been shown to promote the fusion process and provides not only a rich source of vascular supply from the underlying cancellous bone, but also access to pluripotent stem cells within the marrow. Although the blood supply to the lumbar spine has been described, little attention has been paid to relevant areas of the spine most affected by decortication during the posterolateral fusion process. To assess these areas of the spine and attribute some potential importance to spinal fusion outcome, a perfusion study was designed to delineate the vascular anatomy involved in a decortication procedure. Cadaver spines were perfused with a radiopaque contrast material, fixed, decalcified, and cleared en bloc by the method of Spalteholz. Transverse, sagittal, and coronal slabs were made and the vascular supply was documented. The dominant intraosseous architecture of the vertebra reflected a cancellous bone structure, characterized by marrow and a sinusoidal blood distribution within a trabecular matrix. A contrasting architecture could be differentiated in the pars interarticularis that was more consistent with dense, cortical bone. Matrix from this region typified haversian lamellar bone and exhibited parallel osteons that contained a central vascular component. The relevance of this variance could have multiple implications, given the differences between cortical and cancellous bone in function, formation, healing, and remodeling. In posterolateral intertransverse process arthrodesis, the transverse processes and lateral facets are good areas to be decorticated, whereas the pars interarticularis is less attractive.

Expansive midline T-saw laminoplasty (modified spinous process-splitting) for the management of cervical myelopathy

STUDY DESIGN

The authors developed a method of spinous process-splitting laminoplasty using a threadwire saw in a prospective study of 25 patients with cervical myelopathy. This report describes the surgical technique and the results of the expansive midline laminoplasty performed with an threadwire saw.

OBJECTIVES

To compare the efficacy of midline, threadwire-saw laminoplasty with that of the original spinous process-splitting laminoplasty.

SUMMARY OF BACKGROUND DATA

The spinous process-splitting laminoplasty was described by Kurokawa in 1982. Although the procedure has a number of theoretical and practical advantages, it has not been widely used because of technical difficulties.

METHODS

Twenty-five patients who underwent expansive, midline, threadwire-saw laminoplasty from C3 to C7 for cervical myelopathy were studied. The threadwire saw was used to split the spinous processes. The mean follow-up period was 34 months. Neurologic results were evaluated with pre- and postoperative scores, and recovery rates were evaluated by methods described in previous reports using the Japanese Orthopaedic Association scoring system. Radiographic data analyzed included plain radiographs and computed tomography scans. The duration of surgery and the amount of blood lost during this procedure using the threadwire saw were compared with the duration and blood loss that occurred during the original Kurokawa's procedure using a burr.

RESULTS

In all cases, good enlargement of the cervical canal was achieved. The mean increase in cervical cross-sectional area was 36.1%, according to computed tomography scans. No dural tears occurred, and no patients experienced any decrease in neurologic function. The neurologic recovery rate was 72%, which was almost same as the neurologic recovery rate in the original procedure. Using the threadwire saw, the mean duration of surgery was 63 minutes shorter and the mean blood loss was 70 cc less than in procedures using burrs.

CONCLUSIONS

The application of the threadwire saw to split the spinous processes made Kurokawa's procedure simpler, faster, and safer.

The epiconus syndrome presenting with radicular-type neurological features

We report 15 patients with an epiconus syndrome presenting with radicular-type clinical features involving the lower extremities and identify the vertebral level at which the spinal cord terminated. All patients, consisting of 10 men and five women, aged 37 to 71 years, presented with unilateral or bilateral leg muscle atrophy as well as sensory deficit. Unilateral or bilateral reduction or absence of deep tendon reflexes were present in 13 patients, while pathological reflexes were seen in three cases and bladder dysfunction in 10. Prior to presentation, five patients with the epiconus syndrome were mistakingly diagnosed as having different spinal diseases, which were treated surgically. The level of epiconus compromise detected on radiological examination ranged from the lower level of the T10 vertebra to T12-L1 intervertebral disc level, but most frequently at T11-12 disc level. The level of termination of the spinal cord was between T12 and L1-2 disc level, but most frequently at the middle portion of the L1 vertebra, which was on average 1.6 +/- 0.4 (mean +/- standard deviation) vertebrae distal to the epiconus lesions. The presence of different neurological features related to epiconus compromise should be carefully examined with reference to the level of termination of the spinal cord.

Total en bloc spondylectomy. A new surgical technique for primary malignant vertebral tumors

STUDY DESIGN

The study of seven patients with primary malignant or benign aggressive tumors who underwent a new aggressive surgical technique termed "total en bloc spondylectomy" is reported.

OBJECTIVES

To report a new surgical technique of total en bloc spondylectomy for complete, resection of primary spinal malignancy and for oncologic curability.

SUMMARY OF BACKGROUND DATA

The conventional approach for primary spinal malignancy is via intralesional piecemeal resection, and very few reports have described en bloc extralesional resectioning with histopathologically wide or marginal surgical margins.

METHODS

Total en bloc spondylectomy, consisting of en bloc laminectomy and en bloc corpectomy followed by anterior instrumentation with spacer grafting and posterior spinal instrumentation, was performed in five patients with primary malignant tumors and two patients with giant cell tumors. Patients were observed for 2 years to 6.5 years, except for one patient who died 7 months after surgery because of a mediastinal metastasis.

RESULTS

All patients, except one, attained significant clinical improvement after surgery with no major complications. Histologically, the margins were wide or marginal except for the pedicles, and occasionally the spinal canal and the posterior, where they were accepted to be intralesional. One patient died of metastasis that was not directly related to surgery itself. There was no local recurrence.

CONCLUSIONS

The advantages of total en bloc spondylectomy include resection of the involved vertebra(e) in two major blocs, rather than in a piecemeal pattern, and completion of the procedure during one surgical session posteriorly. The "total en bloc spondylectomy" offers one of the most aggressive modes of therapy for primary spinal malignancy.

Regulation of vasomotion of arterioles and capillaries in the cat spinal cord: role of alpha actin and endothelin-1

Ring-shaped vasoconstrictions of arterioles at their branching sites have often been reported in vascular corrosion casts of the brain and spinal cord in rats and cats. It is surmised that smooth muscle cells in arteriolar walls could regulate the blood flow by changing the diameter of the lumen (ie vasomotion). However, few reports have described vasomotion at the capillary (capillaries have no smooth muscle cells). Also, there have been no reports on endothelin-1 in the arterioles and capillaries of the spinal cord. This study was designed to determine (1) the electron microscopic architecture of vasomotion; (2) the immunohistochemical identification of alpha actin and endothelin-1 in the arterioles and capillaries of the spinal cord. Twenty-seven adult mongrel cats were used to study vascular corrosion casts at the lumbosacral spinal cord segments immunohistologically and through scanning electron microscopic observations. Sections of the spinal cord were stained with monoclonal anti-alpha actin and endothelin-1 antibodies. Vascular corrosion casts demonstrated two types of vasomotion: a sausage-like peristalsis and a ring-shaped vasoconstriction at the arteriole and capillary levels. In the immunohistological study, alpha actin and endothelin-1 were identifiable in the vascular wall at the bifurcation, and pericytes were found to contain microfilaments of alpha actin. The ring-shaped vasoconstriction might be regulated by smooth muscle cells in arterioles and by pericytes in capillaries by releasing endothelin-1.

Cadaveric vascular anatomy for total en bloc spondylectomy in malignant vertebral tumors

STUDY DESIGN

The authors studied the vascular anatomy of the thoracic and lumbar spine in cadavers related to the clinical use of total en bloc spondylectomy in malignant vertebral tumors.

OBJECTIVE

To enhance anatomic knowledge on major and associated segmental vessels surrounding the anterior vertebral column of the thoracic and lumbar spine.

SUMMARY OF BACKGROUND DATA

No reports have, to the authors' knowledge, referred clinically to the anatomic relationship between the vascular system and the anterior vertebral column in performing posterior total en bloc spondylectomy on the thoracic and lumbar spine.

METHODS

The authors studied the major vessels, segmental arteries and veins, and tendinous portions of the lumbar diaphragm inserting onto the vertebrae in 21 cadavers to view the vascular system surrounding the anterior vertebral column in the thoracic and lumbar spine.

RESULTS

The aorta descended in direct contact with the anterior vertebral column below T4 or T5 and branched into two common iliac arteries at L3 in one cadaver, at L3-L4 in two, at L4 in eight, at L4-L5 in nine, and at L5 in one. The uppermost intercostal artery originated at T4 or T5, and 48 (14%) variations in 348 intercostal arteries did not originate from the thoracic aorta. Two common iliac veins became confluent at L3-L4 in one subject, at L4-L5 in 13, and at L5 in seven. The inferior vena cava ascended in tight contact with the vertebral column and entered into the vena caval foramen of the diaphragm anterior to the right medial crus. The right medial crus of the diaphragm originated from the vertebra at L1-L2 in one subject, at L2 in two, at L2-L3 in 14, and at L3-L4 in four, whereas, on the left, this ligamentous origin located at L1-L2 in six, at L2 in two, at L2-L3 in 11, and at L3-L4 in two. The first two lumbar arteries ran consistently in the space between the medial crus and the vertebral column.

CONCLUSIONS

Total en bloc spondylectomy conducted posteriorly is less likely to damage the thoracic aorta from T1 to T4 but, distal to T5, the aorta must be carefully retracted anteriorly before manipulation of the affected vertebra(e). For a malignant tumor involving L1 or L2, the medial and, occasionally, the intermediate crura of the diaphragm and the first two lumbar arteries must be treated carefully before spondylectomy. Malignant tumors involving the L3 and L4 vertebral bodies can be approached with a total en bloc spondylectomy technique only when the inferior vena cava has been safely retracted anteriorly.

Symptomatic arachnoiditis ossificans of the thoracic spine. Case report

This report describes a man aged 65 years who developed spastic paraparesis secondary to arachnoiditis ossificans in the thoracic spine. Over 35 years previously, in Southeast Asia, the patient had received repeated lumbar punctures in the treatment of meningitis possibly associated with malarial fever. He had multiple arachnoidal ossifications located at levels from T6 to T9 dorsal to the spinal cord which were well delineated by computed tomography. The lesions were completely extirpated by dorsal route surgery, and the patient had marked neurological improvement after surgery. Histology confirmed that the lesions showed mature bone that formed with an osseous marrow and trabeculae, and the lesions exhibited clusters of arachnoidal cells as well as the proliferation of osteoblasts surrounding the ossified area. Early diagnosis and surgical intervention, however, are mandatory in such cases, if the patient is to attain an acceptable degree of recovery.

Total en bloc spondylectomy for solitary spinal metastases

We have developed a technique for total en bloc spondylectomy through a posterior approach and now report our experience of 20 patients with a solitary or localised metastasis in the thoracic or lumbar vertebrae. There are two steps: an en bloc laminectomy, followed by en bloc resection of the vertebral body with an oncological wide margin and the insertion of a vertebral prosthesis. Pain was relieved in the 17 patients who could be assessed; 11 of the 15 patients with a neurological deficit were much improved, impending paralysis being prevented in 5 patients. There have been no local recurrences. Nine patients are at present alive with a mean follow up of 17.4 months.

Total en bloc spondylectomy and circumspinal decompression for solitary spinal metastasis

We have developed a new surgical technique, 'total en bloc spondylectomy' (TES), to treat a solitary metastasis in the thoracic or lumbar vertebra. This operation is designed as a local cure for the metastatic site and involves the radical resection of the affected vertebra with a wide margin. The spondylectomy consists of two steps: en bloc laminectomy with posterior spinal instruments for stabilisation (first step) and en bloc corporectomy and replacement using a vertebral prosthesis (second step). TES makes it possible to remove the affected vertebra extracompartmentally with its tumour barrier and accomplishes circumferential decompression of the spinal cord. Before clinical practice, we constructed experimental models using cats to examine spinal cord blood flow (SCBF) after ligation of the nerve roots and circumspinal decompression. The changes of SCBF were negligible, so it was proved that TES on one vertebra has little effect on spinal cord circulation. This method was used in 24 patients. Fourteen of the 18 patients with neurological deficits improved remarkably, and the 23 evaluable cases experienced pain relief. Impending paralysis was prevented in all six patients by this surgical intervention. There has been no recurrence of the local tumour after surgery. After a median follow up period of 14.1 months, 12 patients have survived. These data suggest that TES may have a significant clinical value in the treatment of spinal metastasis.

[The effect of total en bloc spondylectomy on spinal cord circulation]

The physiologic and morphologic effects of total en bloc spondylectomy (TES) on spinal cord circulation in cats were studied by spinal cord blood flow (SCBF) and examined with microangiogram and scanning corrosion casts. SCBF decreased significantly following laminectomy (average 22.1%), while circumspinal decompression produced no further decrease. Ligation of the Adamkiewicz artery decreased SCBF only by 19.0% in average and caused no conduction disturbance electrophysiologically. TES on the vertebra at the level of the Adamkiewicz artery produced no morphologic changes in spinal cord vessels and self-regulation of blood flow was also preserved. These findings indicate that total en bloc spondylectomy on one vertebra has little effect on spinal cord circulation.

[A case of dumb-bell-like neurilemmoma of the posterior mediastinum]

A 56 year-old female was pointed out an abnormal shadow on chest X-ray film for the lung cancer screening study. Chest X-ray film showed a round mass shadow at the right superior mediastinum. Chest CT scan revealed the mass was in the paravertebral area abutting on the 2nd thoracic vertebral body and had extended into the intervertebral foramen. Preoperative diagnosis was a dumb-bell-like neurogenic tumor. Operation was carried out by posterior approach in the prone position. At first thoracotomy was done by removing the paravertebral portion of the 2nd and 3rd ribs, and then hemilaminectomy was added. Both the intrathoracic and intraforminal portions of the tumor were completely exposed, and excised. Pathological examination demonstrated the tumor was a typical neurilemmoma originating from the 2nd intercostal nerve. When a neurogenic tumor of the posterior mediastinum has an intraspinal extension, a posterior approach by a simultaneous thoracotomy and laminectomy will be useful to remove the tumor at one sitting.