[The interrelationship between compact tissue defect and bone shaft cavity circulation].

The intraosseous pressure of tissue fluid, the electrical resistance between electrodes and the parameters of hemodynamics in tibial shaft cavity were measured experimentally. It was established that the occurrence and increase of compact defects led to the enhancement of fluid filtration from capillaries and tissue blood filling, whereas the reduction of compact defects led to hemodynamics parameter decrease. The shunting influence of newly formed regenerate bone capillaries cause an arterial wall elasticity increase and volumetric circulation rate limitation. The filtration-and-resorption balance of bone shaft cavity restored and circulation enhanced after compact defect healing.

[Changes in hemodynamics of tibial diaphysis in case of blood flow disorder in superficial femoral artery].

Changes in tibial hemodynamics have been studied experimentally after applying a clamp (n=41) and resection of superficial femoral artery (n=22) in 63 adult dogs. It has been revealed with the help ofrheovasography that, in case of blood flow disorders in the superficial femoral artery, anastomoses with deep femoral artery branches contribute to maintenance of blood circulation in tibia, and in this connection the parameters of tibial blood flow may significantly differe from those of circulation in the leg soft tissues. Preservation of intraosseous pressure all along tibial diaphyseal cavity demonstrates a possibility of using its driving force to compensate for the circulatory insufficiency in the leg soft tissues and, moreover, in that part of the bone the environment of which in ischemia is involved.

[Changes in hemodynamics of the long bone due to tunnelization under pulsing and non-pulsing pressure in a shaft cavity].

In 25 dogs, it was revealed that the pressure in a long bone shaft cavity (IBP) pulsed at relatively high values. According to rheovasography data, the pulse changes of the vascular blood filling of a shaft cavity caused the IBP. The blood filling changes at pulsing IBP produced pulse changes in interstitial fluid amount, at non-pulsing IBP they provided for fluid coming into the interstitial space of the shaft cavity without pulsations. Tunnelization led to appearance of compact substance defect, at the size of which, coming to 2.4% of shaft area, IBP always decreased, remained decreased during 2 months and restored during the third month. The IBP decrease changed the bone hemodynamics.

[Dynamics of the blood supply in the leg soft tissue in the course of experimental defect filling]. / Dinamika krovosnabzheniia miagkikh tkanei goleni pri zameshchenii kostnykh defektov v éksperimente.

Hemodynamics in the leg soft tissues during bone regeneration in the diaphyseal defects separated from surrounding paraosseous tissues, was studied experimentally using 10 adult mongrel dogs. It has been established, that circulation changes occur both in the operated limb and in the contralateral limb. They are most obvious in the operated leg and have a phase character corresponding to posttraumatic period. Restoration of blood flow parameters starts just from the 28th day of the experiment, the parameters become completely stabilized by the end of the experiment (90 days). Bone regeneration in tibial defects is accompanied by circulation increase in the respective limb segment.

[Circulation changes depending on manifestations in soft tissue tensioning in the leg lengthening process]. / Izmeneniia krovoobrashcheniia v zavisimosti ot proiavlenii natiazheniia miagkikh tkanei pri udlinenii goleni.

Surgical intervention was found to intensify circulation in the limb and redistribute the blood flow. Leg lengthening led to arterial inflow limitation due to the magisterial artery strain. The changes were accompanied both by increase of functioning capillaries in number and increase of venous outflow dependence on blood inflow. The decreased after surgery oxygen tension in m. gastrocnemius did not change throughout distraction. The increase of functioning capillaries in number in resting contributed to maintenance of tissue oxygenation in the initial period of distraction, and in case of maximal tissue tensioning hydrostatic pressure increased in the capillaries due to arterial pressure rise. Restoration of the circulation parameters in the fixation period started with an increase of circulation volumetric rate in vessels with preservation of the rest mechanisms of the tissue oxygenation maintenance.

[Healing of "wire tunnels" in tibial diaphysis: data of local X-ray study and densitometry]. / Zazhivlenie "spitsevykh tunnelei" v diafize bol'shebertsovoi kosti po dannym lokal'noi rentgenografii i densitometrii.

Fifteen pelvic extremities from adult dogs were used to perform 60 cross tunnelization of tibial diaphysis with a wire having a pointed groove, 1.8-mm in diameter, at 1,500 rpm. Thirty five leg X-ray films in the lateral projection, which show changes on days 30, 60, 90, 120, 520 after the experiment, were studied. Bony diaphysis tunnelization was found to give rise to a regeneration focus wherein an area of tissue element degradation and an area of introduction of bony fragments into soft tissues were detectable. Changes in the regeneration focus were determined by a response to osseous fragments, which involved the formation of an bony regenerate during a month and to the resorption of the bony matter of an osseous regenerate and osseous fragments in future. Healing of diaphysis defects began with the resorption of a damaged cortical layer. Osteogenesis prevailed at month 2 and ensured healing of cortical layer defects following 4-6 months.

[Effect of Ilizarov tibial lengthening on limb blood flow]. / Vliianie udlineniia goleni po Ilizarovu na krovoobrashchenie v konechnosti u sobak.

The experiment in 23 adult dogs was based on the study of volumetric blood flow velocity in the superficial femoral artery and femoral vein, pulse changes in blood filling of the m. gastrocnemius in the conditions of tibial lengthening to 17.5-23% from the initial length. Complex changes in the blood flow parameters were revealed after surgical intervention and within 7 distraction days. When the distraction ended, the volumetric blood flow velocity in the femoral artery was reduced by 19% and the blood flow out of the vessel was improved by 17%. When fixation was over, the volumetric blood flow velocity in the vessel increased by 37% and the improved outflow preserved. At each experimental stage, there was an increased volumetric blood flow velocity in the femoral vein as compared to its value in the control group, its correspondence to the superficial femoral artery as well as similar dynamics in blood flow changes in the femoral vessels and m. gastrocnemius. The findings show that the vascular system of bone regeneration provides accelerated arterial blood transportation into the venous system during organotypical bone area formation.

Changes in blood flow during tibial thickening by the Ilizarov method.

We studied circulatory changes in dog hindlimb after tibial thickening by the Ilizarov method. Distraction osteosynthesis promoted the increase in blood supply to hindlimb tissues. Changes in blood flow were most pronounced in a distraction bone regenerate after the distraction period. The increase in the volume of distraction bone regenerate determined more pronounced and long-lasting stimulation of circulation in the extremity.

Comparative morphofunctional investigation of vascular pool of the muscles of the elongated extremity using different distractional regimens.

Morphofunctional changes in intra-organ vessels of dogs' muscles were evaluated by rheovasography and stereometry methods of muscular preparations to reveal ATP-ase, biochemical methods were used to determine tissue metabolism indices during elongation of tibia using different distractional regimens 1 mm 4 times per day (manual adjustment) and 1 mm 60 times per day (automatic distraction). The data obtained demonstrate different mechanisms for adequate intra-organ blood circulation in muscles using different distractional regimens.

[The effect of tunneling on the pressure in the tibial cavity in arterial insufficiency in the extremity]. / Vliianie tunnelizatsii na davlenie v polosti bol'shebertsovoi kosti pri arterial'noi nedostatochnosti v konechnosti.

The intraosseous pressure in the diaphyseal cavity of the tibia was investigated in 33 adult dogs after the introduction of the needle for the investigations, tunneling of the bone with a wire and modelling of the arterial insufficiency in the extremity. It was found that perforated defects made in compact substance led to a certain lowering of the pressure. The arterial insufficiency is a cause of stable decrease of the intraosseous pressure.