Muscle blood flow after amputation. Increased flow with medullary plugging.

At below-knee amputation for arterial insufficiency in 31 patients, the muscle blood flow of quadriceps and triceps surae was measured by clearance of 99mTc pertechnetate pre- and postoperatively. In 15 patients, myoplastic amputation was performed and in 16 patients the medullary cavity of the tibial stump was plugged with cortex of the removed bone as well. Plugging caused a two-third increase in muscle blood flow.

The vascularization in the amputation stumps of rabbits. A microangiographic study.

With the aid of microangiography the vascularization in the amputation stumps of 108 rabbits was studied, both in extremities with normal circulation and in those supplied with collaterals. It was found that the vascularization of the normal leg was altered by amputation, with the development of newly-formed, pathological, spirally-twisted vessels. Closure of the stump with myoplasty, however, counteracted this vessel formation, and hypervascularization took place through normal arteries. After amputation of extremities supplied with collaterals, the influence of amputation on collateral function and vascularization in the amputation stump was dependent on the time interval between arterial occlusion and amputation.

Bone vascularization and bone healing in the amputation stump. An experimental study.

The osseous healing process of the amputation stump was investigated in adult rabbits. Histological investigation showed that the medullary cavity was closed after 2-3 weeks, chiefly by endosteal callus. After closure of the cavity there was a gradual spongious change in the bone tip and simultaneously the cortex atrophied and the medullary cavity dilated. After amputation on the crus bone rebuilding dominated, whereas after amputation on the femur deterioration of bone was most noticeable. A combination of amputation and medullary plugging caused a change in the course of healing. The medullary cavity did not close until 7-10 weeks after operation and there was distinct periosteal callus formation. The microangiographic investigation showed a transient hypervascularization in the cortex 3-4 weeks after amputation; whereas after simultaneous plugging of the medullary cavity the hypervascularization continued for up to 7 weeks after operation. Following amputation proximally on the crus the arterial supply of the cortex came mainly from the periost, whereas the cortex after distal amputation was vascularized from the medullary cavity. This finding can be due to an interruption of the arterial supply from the nutrient artery associated with proximal amputation, whereas this artery remains intact with amputation distally on the crus.

Amputation after development of collateral circulation. An arteriographic study in rabbits.

The vascular changes in the amputation stump after amputation on an extremity which is vascularized by collaterals were studied by arteriography in adult rabbits. Amputation on the crus immediately after ligature of the femoral artery caused a retardation in the development of collaterals and a protracted vasoconstriction in the amputation stump. Osseous plugging of the medullary cavity in the amputation stump counteracted the vasoconstriction, and the development of collaterals was improved. When amputation on the crus was performed 3-6 days after ligature of the femoral artery, immediate function of the collaterals and a rapid dilatation of the arteries in the below knee amputation stump were seen, and 3--4 weeks postoperatively arteriovenous shunts developed in the stump. Amputation 7--10 weeks after ligature of the artery involved a more pronounced shunt development in the amputation stump. After amputation on the femur only slight differences were observed in the development of collaterals and the vascularization in the amputation stump compared with findings after amputation on the crus.

Intracardial arteriographic study on vascular changes in amputated rabbits.

The vascular changes in rabbits after amputation were studied in vivo with arteriography, after intracardial injection of contrast. In the amputated extremity an initial vasoconstriction of the arteries was found. Thereafter changes were observed in arteries and veins, both in the operated and contralateral extremities, depending on the level of amputation and the manner in which the stump was closed. After amputation distally on the extremity and after stump closure without myoplasty arteriovenous shunting was observed in the amputation stump. Arteriovenous shunts were not seen after knee disarticulation and after proximal amputation on crus with myoplasty. Inactivity of the muscles in the amputation stump is supposed to be the cause of the shunt formation. After mid-femur amputation a permanent vasoconstriction of the femoral artery was observed, whereas artery dilation was seen when amputation on the femur was combined with plugging of the medullary cavity.

Muscle blood flow after amputation with special reference to the influence of the amputation level. Assessed by 133 xenon and histamine. An animal experiment.

Amputation on rabbits was found to change the muscle blood flow (MBF) in the limb subjected to surgery as well as in the contralateral extremity, depending on the technique used for amputation and the level at which it was carried out. Amputation was immediately followed by a reduction in MBF in the stump. After amputation of the crus and knee disarticulation, the flow was normalized a few days later and exceeded the preoperative mean flow. After amputation of the femur such an increase in flow was not seen, but when osseous plugging of the medullary cavity was applied, the MBF in the stump was intensified even after amputation of the femur.

Muscle blood flow after amputation with special reference to the influence of osseous plugging of the medullary cavity. Assessed by 133 xenon and histamine. An animal experiment.

The muscle blood flow (MBF) in rabbits subjected to amputation of the crus was assessed by means of 133 Xenon and Histamine. It was shown that after the operation the flow in the amputation stump was initially reduced. MBF in the stump increased more rapidly and stayed at a higher level after closure by myoplasty than after amputation without myoplasty, and it was still further stimulated after osseous plugging of the medullary cavity.