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A lightweight polymeric composite material is described for use with bone grafting for the restoration of complex contour defects of the neurocranium. Custom fabrication based on three-dimensional computed tomography provides an anatomically precise reconstruction with reestablishment of the bony integrity of the skull.

A composite biocompatible material made of polyethyleneterephalate (Dacron) and polyetherurethane was fabricated as an aid to bone grafting for the reconstruction of large bony defects of the craniomaxillofacial regions. Bone graft material is placed within the confines of the Dacron-urethane implant and new bone forms to the shape imposed by the implant.The principle application of this material has been for the reconstruction of defects of the neurocranium and of the mandible [1–5]. A number of other applications have been studied including reconstruction of long bone discontinuity defects [6], reconstruction of an infant's anterior chest wall [19], the prosthetic replacement of large defects of the cervical trachea [7] and as a potential material for a thrombo-resistant small diameter vascular prosthesis [8].

The purpose of this report is to present out 5-year experience in reconstructing large bony defects in the cranial vault of 16 patients. The method employs an alloplastic implant device made of elastomer-coated cloth mesh, used in conjunction with bone grafting [D. L. Leake and M. Habal, J. Biomed. Mater. Res., 10, 555 (1976)]. The cranial defects ranged in size from 6 X 6 cm to 15 X 17 cm. The defects were in the frontal, temporoparietal, and occipital regions. Particularly challenging was the frontal-orbital region involving the superciliary ridges. The alloplastic implant provides controlled contour of the bone graft material while providing strength and stability during healing. The implant has adequate but not complete ridigity, allowing adaptability inthe operating room. The elastomer used is a polyetherurethane. Any biocompatible cloth mesh can be used, but Dacron [poly(ethylene terephthalate)] was chosen because of its extensive implant history. Contrasted with reconstruction using only bone, where as many as half of the cases had uneveness and were found to be anesthetically unsatisfactory, the technique described here has resulted in aesthetically excellent results and an intact neurocranium in the 16 patients studied thus far.

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. β-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.

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.

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.

A method for reconstructing osseous contour defects, including the mandible, which employs an alloplastic tray made of polyether urethane and Dacron mesh for use in particulate cancellous bone grafting, has been described. The alloplastic tray has exhibited those qualities which are desirable in an implant device. New bone formation within this tray occurs according to the configuration imposed by the contour of the tray. This suggests possible use in the reconstruction of bony contour defects in other parts of the body where esthetic considerations are of importance.

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.

A method of reconstructing contour defects, including stress-bearing bones, employing particulate cancellous bone for bone induction in a composite alloplastic device of polyethylene terephthalate mesh cloth impregnated with polyether urethane has been described.

Significant hemorrhage following aspirin ingestion may occur in patients without a pre-existing bleeding disorder. In the patient presented here, extensive dental extractions, superimposed on a probable aspirin-induced bleeding diathesis, resulted in prolonged hemorrhage. Bleeding was controlled with platelet transfusion. Patients should be advised to abstain from aspirin for a week prior to operation, and aspirincontaining compounds should not be prescribed postoperatively for analgesia. Two aspirin tablets may impair platelet function for up to one week.

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.

Anaerobic Bacteroides infections are being noted more often. Two patients were seen at Harbor General Hospital within the last year with osteomyelitis of the mandible secondary to Bacteroides infections. They were treated successfully with clindamycin.

Mandibular and other bony contour defects may be reconstructed using particulate cancellous bone grafting in an alloplastic tray fabricated of polyethylene terephthalate cloth mesh and polyerher urethane elastomer. The bone graft material, taken from the iliac crest, is supported in the tray which provides stability and imposes esthetic form. New bone is formed and provides continuity within the graft and to the host bone within a period of 6–12 weeks, depending on the size of the defect. The initial evaluation of this technique was carried out in experimental animals and has now been applied to the reconstruction of a variety of osseous contour defects in the facial and cranial bones of man.

The time has arrived when certain standards are to be introduced to control the introduction of and appropriate use of surgical implant devices. Now is the time for the professional groups involved in standards and medical device legislation to become active and develop surgical implant device standards to be applicable for the future. A commission could be established to work with FDA in respect to the requirements for surgical implant devices. It is time for the clinical organizations involved in writing consensus standards to cooperate in the introduction of surgical implant device standards.

The best possible implantable biomaterial for bony contour abnormalities is autogenous bone grafts. However, some conditions may be present that alloplastic materials have to be utilized; such alloplastic material had to be inert and there should be no reaction to it in the body. The composite graft is a combination of the two different materials described. To have a better take, the bone graft used is grinded with a craniotome, and then mixed with blood. This produces an inductive matrix that promotes osteogenesis. The alloplastic material is a tray or a template where the bone is placed, in or on, to allow for complete solidification and better healing. The material used is polyetherurethane impregnated poly(ethylene terephthalate) (Dacron) which is known as osteomesh. In few instances, the osteomesh was removed with complete solidification of the bone, resembling the skull in the case of a skull defect. For over 10 years, since the success in experimental animals (1), this composite graft has been used in clinical situations with varying degrees of success (2).

This study presents a histologic evaluation of the healing process of dental extraction sites in dogs with and without the use of collagen sponge as an extraction site dressing. The healing process was evaluated at 3 days, 1 week, and 6 months after tooth extraction and appears comparable in both collagen-filled and nonfilled extraction sites.

Surgical defects were created in the superior border of the mandible in five mongrel dogs and filled with particulate cancellous bone taken from the ilium and held in place with a bovine collagen stent. New bone formation was studied radiographically, histologically, and by intravital tetracycline labeling. The stent was adequate to maintain the bone particles in position and was well-tolerated by the tissues. The length of survival of the collagen stent was related to the degree of tanning.

Finger joint arthroplasty is a method of replacing defective and diseased delicate finger joints. Multiple new finger joints have been introduced to replace function of the fingers. The ideal joint for replacement arthroplasty should have complete fixation in the long shafts of the bones in the hand and fingers, and a hinge that is durable. The design proposed here will produce these ideal conditions. Polyetherurethane-Terephthalate has those particular characteristics. Long term implantation in man has shown that bones ingrowth is feasible. The experimental work presented, suggest the cloth mesh part can be used for joint replacement as a hinge, because it withstood the mechanical changes. There was no material fracture noted, but the mechanical changes were basically of fraying, crazing, and fragmentation. Over 6 million cycles were used. The results in hand surgery is an integral part of this fast developing field.

The best possible implantable biomaterial for bony contour abnormalities is autogenous bone grafts. However, some conditions may be present that require use of alloplastic materials. Such alloplastic material must be inert and there should be no reaction in the body to it. The composite graft described in this chapter is a combination of the two different materials described. To have a better take, the bone graft used is ground with a craniotome, and then mixed with blood. This produces an inductive matrix that promotes osteoneogenesis. The alloplastic material is a tray or a template where the bone is placed “in”, “on”, or “under” the implant to allow for complete solidification and better healing. The material used is polyetherurethane-impregnated terephthalate (Dacon) also referred to as osteomesh (R) (Xomed Corporation, Jacksonville, Florida). In a few instances the osteomesh was removed and we noted complete solidification of the bone (resembling skull in the case of the skull defect). For over eleven years, since the success in the experimental animal [1], this composite graft was used in clinical situations with good success [2] in over 100 patients. These patients treated were selected and a strict set of indications and contraindications were instituted and implemented, prior to the applications of this treatment in the individual patient.

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.

A method for precise radium needle implantation in the therapy of tumors of the tongue and floor of the mouth is described. The device is fabricated as a two-piece acrylic splint that may be applied easily either under local or general anesthesia. It provides the radiation therapist with parallel positioning of the needles and an optimum distribution pattern. Fabrication and clinical application of the device are presented.

Summary This new method of reconstructing osseous contour defects employs an alloplastic tray fabricated of polyethylene terephthalate cloth mesh impregnated with polyether urethane. A mold of the defect is made using standard prosthetic techniques. The cloth mesh saturated with catalyzed urethane is draped over the mold and cured in an air-circulating oven. The tray thus formed is sterilized by autoclaving. Autogenous, particulate cancellous bone taken from the iliac crest is used to fill the tray. The tray is implanted subperiosteally and imposes form and stability over the bone particles which progressively form new bone. This technique was initiated in 30 mongrel dogs where discontinuity defects of the mandible ranging from 2 to 4 cm were reconstructed. Osteogenesis was assessed radiographically, histologically and by intra-vital labelling in 80 percent of the dogs. Failure was attributed to behavioral problems in 6 dogs causing extrusion of the implant. Lamellar bone appeared by 3 months and progressed to form cortex (Leake and Rappoport, 1972). In man, the technique has been used to reconstruct discontinuity defects of the mandible ranging in size from 1.5 to 12 cm in ten patients, to augment atrophic mandibular alveolar ridges in four patients, and in two patients to reconstruct defects of the cranium. This new technique overcomes many of the problems of contour reconstruction. New bone forms regularly to fill in the prefabricated alloplastic tray. Bone formation is adequate for stress bearing in a period of 6 to 12 weeks depending on the size of the defect.

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.

An alloplastic tray made of poly(ethylene terephthalate) cloth mesh and poly(ether urethane) used in conjunction with cancellous bone-chip grafts is the basis for this new method for reconstructing facial osseous contour defects. The tray can be prefabricated in quantity and at low cost for standard defects, such as discontinuity defects of the mandible or for chin augmentation. It can be custom-fabricated for specific defects in individual patients as, for example, gunshot wounds to the forehead. The materials were chosen because of their known histocompatibility, the ease of fabrication, and because the materials can be molded to form esthetic contours. They can be easily modified at the time of surgery. Sterilization is by autoclaving. Initial studies were undertaken in mongrel dogs where mandibular discontinuity defects in the range of 2–4 cm were reconstructed. In man, the technique has been used to reconstruct discontinuity defects of the mandible ranging in size from 1.5–12 cm in 16 patients. Atrophic mandibular alveolar ridges have been augmented using this technique in 7 patients, thus providing an adequate alveolar ridge for dentures. Two patients with defects of the skull secondary to gunshot wounds have had frontal bone restoration using this method.Reconstructions of the ear, the chin, and the orbital floor are currently being evaluated. This technique overcomes many problems of esthetic contour reconstruction and combines the use of autogenous cancellous pmarticulate bone and a tissue-compatible synthetic composite material.

The authors describe a technique for afterloading a radium implant. A mold made from the patient's oral lesion and surrounding tissue is used in planning and carrying out implantation into the lesion. Advantages of this system include more precise implantation, decreased irradiation of personnel, and an improved teaching model.

Stensen's duct was ligated in 18 mature Sprague-Dawley rats and the parotid gland was examined at intervals of up to 90 days. Standard preparatory techniques were used for light and electron microscopy. Parotid tissue decreases with time following ligation of the duct. The course from 1 week onward is one of progressive atrophy; at 3 months the number of identifiable acini is greatly decreased. The controls remained unchanged throughout the course of the study. Ligation of the parotid duct will produce glandular atrophy. The clinical implications are that for some parotid conditions ligation may be an effective treatment which avoids the hazards of parotid surgery.

Mandibular fractures in young children are difficult to treat by means of the standard procedures used in reduction and fixation of fractures in adults. Achieving stable intermaxillary fixation with arch bars or interdental wiring (for example, Ivy loops) is difficult because of the shape of the clinical crowns of the deciduous teeth. Open reductions are complicated by the presence of the permanent tooth buds. These procedures may be avoided by employing splinting techniques that make use of orthodontic bands and labial and lingual arch bars, or acrylic splints with circummandibular wires. Often, these splinting techniques provide adequate stability without intermaxillary fixation.

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.

The Medical Device Amendment of May 28, 1976, to the Food and Drug Act empowers the Food and Drug Administration to regulate and set standards for all medical devices from tongue blades to dialysis units. The FDA has set up "advisory panels" with consumer, industry, and professional representation to offer it advice as to whether particular devices require standards, premarket clearance, or quality control. The involvement of nongovernmental agencies in the writing of standards is hoped for but not assured. It is unlikely that cost will be a factor in assessing safety and efficacy. There is ample opportunity during the administration of the law to "lobby" the FDA either directly, through the advisory panel hearings, or in public hearings. Everyone interested in medical devices is concerned about their safety and efficacy. Standards themselves, however, must also be relevant, safe, efficacious, and cost-effective. Standardsmaybe written and the law administered