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Biomedical subjects

H Burchardt

Publications and source records attributed to H Burchardt.

28 records · Page 2Linked to original sources
PubMed1980

Autogenous cortical bone grafts in the reconstruction of segmental skeletal defects.

The results of using segmental cortical autogenous bone grafts to reconstruct defects created by resection of tumors were analyzed in forty patients. Thirty-three patients had dual grafts while seven had a single fibular graft. Dual grafts were used for major bones (humerus, femur, and tibia without fibula) while single grafts were used for the radius and for the tibia when the ipsilateral fibula was intact. Thirty patients had good or excellent results; seven, fair; and three, poor results. In twenty-five patients primary union was achieved within tweleve months and in two, in twenty months, while twelve patients required a second, supplementary cancellous graft at the site of non-union to obtain stability. One patient required removal of an infected graft and had a poor result. Stress fractures of the grafts occurred in eighteen of the forty patients after union had occurred. The stress fractures healed in fifteen of these patients: in six with no treatment (the fracture was identified retrospectively), in seven with external immobilization, and in two after bone-grafting of the ununited fracture. There were three persistent non-unions of stress fractures despite bone-grafting, internal fixation, and electrical stimulation, and these account for two of the three poor results. The length of the defect did not affect the incidence of non-union but it did affect the number of fatigue fractures. The shorter grafts (7.5 to twelve centimeters) were associated with a 33 per cent incidence of non-union (four non-unions of twelve grafts) while the longer grafts (twelve to twenty-five centimeters) had a 32 per cent rate of non-union (nine non-unions of twenty-eight grafts). The incidence of fatigue fractures in the longer grafts (58 per cent) was much greater than that in the shorter grafts (17 per cent). The grafts decreased in density during the first six months but gradually regained their mass and were generally comparable to normal cortical bone at two years. As the patients became functiona, most (55 per cent) of the the grafts became more dense than normal, some (34 per cent) remained the same, and a few (11 per cent) became less dense. Similarly, some (32 per cent) hypertrophied, most (58 per cent) remained the same size, and a few (9 per cent) atrophied. There was little morbidity (three of forty patients) associated with graft procurement. In twelve patients an additional graft was implanted experimentally, labeled with tetracycline, and subsequently removed at the time of a secondary procedure. These grafts were analyzed to determine if human grafts were repaired in the same fashion as grafts in experimental animals. The studies showed that human grafts are repaired in the same fashion, but that the sequence takes approximately twice as long as it does in the dog.

Adolescent↗
PubMed1978

Freeze-dried allogeneic segmental cortical-bone grafts in dogs.

Forty-four adult male mongrel dogs were used to compare segmental cortical freeze-dried allogeneic bone grafts with fresh autogenous, freeze-dried autogenous, and fresh allogeneic segmental cortical grafts. Group I consisted of bilateral fresh autografts as external controls; Group II, a fresh autograft on one side for internal control and a freeze-dried autogenous graft on the other side to evaluate the effect of freeze-drying on repair; Group III, a fresh autograft on one side and a fresh allograft on the other side to measure the differences between autogenous and allogeneic grafts; and Group IV, a fresh autograft on one side and a freeze-dried allogeneic graft on the other to see if freeze-drying altered the repair of allogeneic grafts. The grafts were analyzed qualitatively over a six-month period by the use of interval roentgenograms to determine the times of graft-host union and the incidence of fatigue fractures. Six months after operation, the repair processes in the four groups were compared quantitatively with respect to biological repair and physical strength using torsional stress-testing, tetracycline labeling, and microradiography. The results indicate both qualitatively and quantitatively that: (1) fresh bilateral segmental cortical autografts show reproducible characteristics, so that the canine fibula furnishes a satisfactory model (Group I); (2) freeze-drying does not inhibit the repair process per se (Group II); (3) fresh allografts are rejected in varying degrees of intensity (Group III); and (4) freeze-drying does not protect cortical allogeneic grafts from such rejection (Group IV).

Animals↗
PubMed1975

Physical and biological aspects of repair in dog cortical-bone transplants.

The amount of repair and the time required to accomplish repair of four-centimeter segmental fibular transplants in twenty-one male adult dogs were determined at from two to forty-eight weeks after transplantation by torsional stress testing, microradiography, and tetracycline labeling. The transplanted cortical bone was greatly weakened at from six weeks to six months but was nearly normal at one year. The strength of the transplant appeared to be related to the amount of porosity of the matrix rather than to the quality or completeness of biological repair. Spatially, the repair was ordered rather than random. The initial resorption caused increased porosity which was slowly offset by apposition of new bone, a process which was dependent on general skeletal metabolic activity. Although physical strength was near normal at forty-eight weeks, only 60 per cent of the transplants had been remodeled.

Animals↗
PubMed1975

Repair of experimental autologous grafts of cortical bone.

Fresh autologous segmental grafts of fibula, four centimeters long, were obtained from thirteen adult dogs. Holes were drilled in each before replantation. The amount of repair was determined after intervals of from four to twenty-four weeks. Torsional stress testing showed that the six drill holes 500 micrometers in diameter confined within an expanse of two centimeters did not mechanically weaken the transplants at the time of surgery. The drill holes were rapidly filled with cancellous bone which matured to cortical bone within twelve weeks. Microradiography and tetracycline labeling of drilled and non-drilled grafts demonstrated similar biological reparative patterns.

Animals↗
PubMedDate not supplied

Sonographical findings in Whipple's disease. A case report with regard to the literature.

We present a case report of a 60-year-old male patient and subsequently discuss sonographical findings in Whipple's disease. This particular patient showed an intraabdominal tumorous mass. Symptoms of a malabsorption disorder were absent. Computer-assisted tomography and radiological examination could not determine the origin of the tumor. Sonography demonstrated a polycyclic hyperechoic mass in the root of the mesentery. The small intestine was not distended and showed normal peristalsis. Its wall was hyperechoic concentrically thickened. Final diagnosis was established from a diagnostic laparotomy showing enlarged lymph nodes and distended lymphatic vessels. Based on the literature the described sonographical findings seem to be typical in cases of Whipple's disease.

Humans↗