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Although it is well known that silicone gel breast implants (SGBIs) produce many "local" complications (i.e., pain, hard fibrous capsules, disfigurement, chronic inflammation, implant shell failure) and necessitate frequent surgical revisions, no large cohort retrospective quantitative analysis of clinical data has been reported to date, especially for the prevalence of failures and additional surgeries. Data from 35 different studies that encompass more than 8000 explanted SGBIs have now been analyzed and are reported here. Because examination of a prosthesis when explanted is the definitive method for determining shell integrity, the only studies that were used were ones that reported implant duration, the total number of SGBIs explanted, and the number of SGBIs for which shell rupture or failure ("not intact") was confirmed upon surgical removal. An exponential regression plot of data indicated a direct correlation of implant duration with percent shell failure (r2 = 0. 63 and r = 0.79 ). SGBI failure was found to be 30% at 5 years, 50% at 10 years, and 70% at 17 years. The failure rate was 6% per year during the first 5 years following primary implant surgery. ANOVA comparison of three implant age groups (mean implant durations of 3. 9, 10.2, and 18.9 years) indicated a highly significant statistical correlation of percent failure with implant duration (p < 0.001). Complications necessitating at least one additional surgery occurred for 33% of implants within 6 years following primary implant surgery. Shell failure was found to be an order of magnitude greater than the 4 to 6% rupture prevalence suggested by the AMA Council on Scientific Affairs in 1993, the 0.2 to 1.1% cited by manufacturers at that time, and the 5% rupture that was stated to be "not a safety standard that the FDA can accept."

Success in the use of custom-fabricated Silastic implants in patients with facial contour defects led us to utilize this method in reconstructing mandibular defects. However, mandibular reconstruction with alloplastic material is quite difficult because of the presence of continuous stress and motion in that region. The evolution in the use of the mandibular implant from the commercially available one to the K-wire reinforced, prefabricated, silicone implant was largely dependent on the availability of silicone and the ultimate result obtained. In the past few years, about 30 subdermal implants were inserted. Some of those implants were placed immediately into patients undergoing resection for tumor. The implant was prefabricated prior to surgery from x-ray measurements of the anticipated segment to be resected; it was then used to reconstruct the defect prior to the final closure of the operative wound. Other implants were manufactured 6–18 months after resection for tumor or for deformity as a result of trauma. The implants were used to reconstruct the facial defects and to correct the functional abnormality, such as drooling or deviation of the affected side by the unstable mandibular segment. Patients with severe congenital malformation have soft tissue deficiency in association with their bony malformation. Therefore, implants in such conditions were doomed to failure. Patient selection is the key to successful implantation.

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.

Morris Hepatoma experimental tumor in ACI rats is treated with small anodal direct current via an implantable power pack unit. There was major retardation in tumor growth when the treatment was started early. There was enhancement of tumor growth when the treatment was started early and then was discontinued. There was no statistical difference in growth control of the experimental tumor when the electrotherapy was given after the half-life of the tumor was achieved. This last point will be the most important to the clinician scientist, for it simulates the clinical situation that faces the treating physician.

An evaluation of the biophysical changes of methylcholanthrene induced tumor (M4) in laboratory animals receiving four different alloplastic implants was conducted. The implants are silicone, polyether urethane, poly(methyl methacrylate), and bioglass. The tumor was allowed to grow to a large size in 28 days and then removed by shelling it from the surrounding tissue. Three different analytic volumetric measurements were carried; size in cm3, volume in milliliters and weight in grams. Statistical analysis on the three different analytic measurements did not disclose any significant differences in tumor growth potential between the control and the experimental groups. We conclude that in this study we were unable to demonstrate any tumor "facilitation" effect by any of the implantable polymers used. Therefore, there is no contraindication in using the polymers to reconstruct defects produced by cancer ablative procedures.

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.