Comparative study of the thromboresistance of Dacron combined with various polyurethanes.

In vitro tests were carried out on Dacron samples differently knitted and on Dacron vascular prostheses coated with various urethanes. All the materials were put in contact with human platelet-rich plasma; the subsequent assay of three platelet released substances, i.e. beta-thromboglobulin, platelet factor 4 and thromboxane B2, as well as the quantification of platelet retention, were used to establish the degree of thrombogenicity of the material itself. In some cases Dacron-urethanes composites showed better thromboresistance than any other materials conventionally used in vascular surgery.

Evaluation of autologous cancellous bone grafting of mandibular discontinuity defects in dogs using a Dacron-urethane prosthesis.

Reconstruction of 2 cm discontinuity defects using autologous cancellous bone chips and a Dacron-urethane prosthesis was evaluated in four canine mandibles. Histologic studies were performed on specimens taken six and 12 months after bone grafting. All four grafts were completely incorporated, producing a reconstruction that conformed precisely to the desired shape. Remodeling resulted in a trabecular pattern similar to that of the normal mandible. The prosthesis was well tolerated and did not elicit an inflammatory response.

Postoperative irradiation of fresh autogenic cancellous bone grafts.

Discontinuity defects were created in the mandibles of dogs and then reconstructed immediately with fresh autogenic cancellous bone grafts and Dacron-urethane prostheses. The grafts were irradiated to a total dose of 5000 rads after waiting intervals of between 3 and 12 weeks. Nonirradiated grafts served as controls. The grafts were evaluated clinically, radiographically, and histologically. There was complete incorporation of all grafts, regardless of the interval between surgery and radiotherapy. There were no soft-tissue complications. The controls were distinguishable from the irradiated grafts only by the presence of hematopoietic bone marrow. Fibrofatty marrow was observed in the irradiated grafts. Theoretical support for this technique is found in the biology of cancellous bone grafting and the pathology of radiation injury. In view of the difficulties associated with mandibular bone grafting in preoperatively irradiated patients, a new method of reconstructing selected cancer patients who require both mandibular resection and radiotherapy is suggested.

Autologous corticocancellous bone paste for long bone discontinuity defects: an experimental approach.

A number of materials have been used in treating long bone discontinuity defects, some with rewarding results and some without. These materials vary from autologous, allogenic, and xenogenic grafts, to bone implants. Other inorganic implants, such as plaster of Paris and gold, have been used, most inducing a strong inflammatory reaction. In this experiment, a paste of autologous corticocancellous bone particles was used to reconstitute discontinuity defects in long bones. The defects were healed to a solidified state within six months. This finding confirms our previous work; in membranous bone discontinuity defects, autologous corticocancellous bone gave best overall results either when used alone or with a template carrier for contouring purposes.

A study of autologous cancellous bone particles in long bone discontinuity defects.

Long bone discontinuity defects in dogs were restored by particulate autologous cancellous bone grafts and a Dacron-urethane mesh implant. In six months the discontinuity defects were filled by new bone formation, which was analyzed histologically, radiographically, and by densitometric methods. The postulated mechanism is a field phenomenon of bone induction. The discontinuity defects remained unrestored in the control groups without bone graft material. In the dogs killed at three months incorporation of the graft material was incomplete in the central area of the defect.

Use of a craniotome for obtaining cancellous bone and marrow from the ilium.

The ilium is a rich source of cancellous bone and marrow for grafting. Grafts can be harvested very rapidly with a standard craniotome. The clutch mechanism prevents inadvertent soft tissue injury if both cortical plates are perforated. The surgical approach is similar to that used in other techniques. No complications have been encountered.

Interface radiation dosimetry in mandibular reconstruction.

When a beam of radiation crosses the interface between two substances, secondary electrons are generated. This results in enhancement of the absorbed dose of radiation roughly proportional to the difference in atomic numbers. Interfaces are created in reconstruction of the mandible with implantable trays containing hematopoietic bone marrow and cancellous bone chips. Radiation was measured in tissue-equivalent material surrounding mandibular tray implants of titanium, vitallium, stainless steel, and Dacron/polyetherurethane. The absorbed dose was enhanced by 29% to 36% adjacent to the metallic trays; 1% dose enhancement was noted adjacent to the Dacron/polyetherurethane tray. We conclude that, when radiation therapy is necessary following mandibular reconstruction, homogeneity of dose is maintained and local soft-tissue reactions to excessive irradiation may be avoided by using a nonmetallic tray.

Implantology for correction of cranio-facial defects with an elastomer composite and bone.

The correction of cranio-facial disfigurement in the upper part of the face is the most difficult to achieve. Various materials have been utilized and are still in use. Each has advantages and disadvantages. Autogenous bone has been used with good results, except for the unacceptable irregularities of the forehead and upper orbital region. The combination graft offers the advantages of both: the bone graft will be in contact with the dura, the periorbita and the contaminated sinuses. The polyrane implant produces a smooth and contoured forehead and immediately protects the vital structures during osteoneogenesis. Twenty-six selected patients had this technique used to correct their deformity without any incidence of major complication.

Design and materials evaluation for a dental implant system: carbon coated tooth replicas.

32 carbon coated tooth replicas were implanted in the jaws of 8 mongrel dogs for periods ranging from 3 months to 2 years. Fourteen of 16 molor implants and 10 of 16 premolar implants had 0.5 min. of mobility or less. Histology of specimens from 4 dogs sacrificed at 3 months showed new bone directly in contact with the implant surface.

Agranulocytosis associated with an infected mandibular fracture.

This report describes a case of agranulocytosis associated with an infected mandibular fracture. Because agranulocytosis is most frequently associated with drug sensitivity, drug therapy is usually stopped or changed when the disease is discovered. This case demonstrates the need to evaluate the causes of agranulocytosis before stopping or changing a patient's medications.

Repair of major cranio-orbital defects with an elastomer-coated mesh and autogenous bone paste.

We present a method for repairing defects in the craniofacial region in which an elastomer-coated mesh is used as a template with bone paste. The method was developed by animal experimentation first, and then successfully used in the maxillofacial and mandibular regions. We have used this method to repair 16 craniofacial defects with satisfactory results, and complications have been kept to a minimum.

Comparison of ilium to rib for bone grafting in defects of canine mandibular alveolar fidge.

The behavior of iliac and rib grafts in surgically created defects in canine alveolar ridges was investigated. Despite the greater amount of potentially osteogenic tissue in the iliac graft, no significant qualitative differences were noted in the bony remodeling for a year. However, the rib grafts did form a mature superior cortical border significantly more rapidly, leading to speculation on the advantages of rib over iliac graft in alveolar ridge grafting.

Reconstitution of craniofacial osseous contour deformities, sequelae of trauma and post resection for tumors, with an alloplastic-autogenous graft.

Our experience using a new technique for reconstructing contour defects of facial bones has been presented. It employs particulate, cancellous bone and an implantable prosthesis accurately fabricated of polyether urethane and polyethylene terephthalate cloth mesh which can be produced in a variety of configurations. A mannequin made of these materials displaying the various parts of the craniofacial complex that have been restored or are currently under investigation is shown in Figure 10. Large cranial vault defects, orbital floors, mandibles including chin augmentation, and nasal bone deformities have been successfully restored in man. Restoration of the pinna of the ear is currently being evaluated in laboratory animals.

Craniofacial and mandibular osseous contour reconstruction: the use of a new "combination" graft.

The use of autogenous bone graft to repair major defects is most feasible biologically. When the bone could not be shaped or carved to fit a given defect, the use of solid alloplastic biomaterial implants gained wide popularity. We are describing a new method wherein a "combination" graft is used. It possesses the advantage of the dependence on autogenous cancellous bone graft, and the added bone inducing capability of a recently developing biomaterial implant (Polyurethane-Terephthalate). The results obtained in the repair of major defects in patients after ablative surgery, or as sequelae of trauma, document the advantages of this new mode of treatment. In selected patients with major defects due to deficiency or absence of the osseous framework of the face, the use of "combination" grafts has proven to be the most appropriate form of repair.

Contouring split ribs for correction of severe mandibular atrophy.

A method of contouring split ribs for use in augmentation of the atrophic mandible had been described. Symmetry, arch, and alveolar ridge form are excellent. Placement of the rib graft passively on the ridge is easier than use of a single rib with vertical saw cuts.

A new method for reconstruction of major defects in the cranial vault.

A new method for reconstruction of cranial vault defects is described. A combination graft made of both alloplastic and autogenous materials combines several advantages to produce adequate strength and a smooth contour.