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Biomedical subjects

C A Homsy

Publications and source records attributed to C A Homsy.

At least 19 recordsLinked to original sources
PubMed2000

Soft porous PTFE-composite alloplasts: tissue-bonding characteristics.

Experimental and clinical investigations over the past three decades have validated numerous hypotheses about tissue bonding of prostheses. Highly porous PTFE composite has been demonstrated to be an effective, inert, scaffold-like matrix onto which other materials can become physically bonded to achieve a tissue-specific result. Hydrophilic agents such as carbon and aluminum oxide stimulate ingrowth of fibroblasts that secrete collagen. These additives promote a robust and durable alloplast-soft tissue union composed mostly of collagen that is watertight. Bone-growth stimulants-such as hydroxyapatite-when added to highly porous PTFE stimulate tissue ingrowth and maturation that is more bone like.

Animals↗
PubMed1984

Proplast stabilized stemless trapezium implant.

Forty-five stemless Proplast-covered silicone rubber trapezium implants were used in 40 patients after trapeziectomy for either osteoarthritis, rheumatoid arthritis, or trauma. Three implants were later removed from two patients because of traumatic dislocations. One implant was removed from a patient after trauma because of persistent pain. Five patients were followed from 40 to 44 months; nine patients were followed from 31 to 39 months; 15 patients were followed from 20 to 29 months; six patients were followed from 14 to 19 months; five patients were followed from 6 to 9 months. The average follow-up time was 24 7/10 months. Before surgery 5% of the patients had continuous spontaneous pain, 35% of the patients had pain with all motion, and 60% of the patients had pain with limited normal daily use. At this time of our report, 65% of the patients are without symptoms, 21% of the patients have slight intermittent pain, and 14% of the patients have pain with strenuous use only. Tripod pinch improved 243% in male patients and 113% in female patients. All patients have good circumduction and metacarpophalangeal (MP) and interphalangeal (IP) joint motion. The stemless feature permits relatively free metacarpal joint motion without great stress being applied to the capsule that is covering the implant.

Arthritis, Rheumatoid↗
PubMed1982

A comparison of porous composite PTFE/graphite and PTFE/aluminum oxide facial implants in primates.

Comparison of tissue ingrowth density values for Proplast I and its aluminum oxide analog, Proplast II, when implanted on the primate infraorbital rim and inferior border of the mandible, showed no difference between the two test materials. A similar comparison of local cellular response ratings showed slightly less response to Proplast II. Microscopic and clinical examination did not otherwise reveal any significant differences in biologic reaction to these materials.

Aluminum↗
PubMed1982

Growth of tissue into a porous, low modulus coating on intramedullary nails: an experimental study.

The ingrowth of tissue into a coating of inert, highly porous, low-modulus composite of polytetrafluorethylene polymer and pyrolytic graphite on four-fluted intramedullary nails was used for stabilization of middiaphyseal femoral osteotomies and examined by microangiography. The observations were correlated with information obtained by histologic, microradiographic and tetracycline fluorescence technology. There was rapid healing of the osteotomy. The coating was invaded throughout by blood vessels and fibrous tissue. Invasion by bone was negligible. The composite thus appeared to retain its initial flexibility when implanted into the femoral intramedullary cavity. The force to distract both coated and uncoated nails was measured on intact femora. The unit retention strength increased to an average of 6.3 kg/cm2 up to 24 weeks, which is consistent with reported values. The composite would thus appear to have potential use as a coating for endoprostheses to produce enduring physiologic fixation.

Animals↗
PubMed1980

Obliteration of traumatically induced articular surface defects using a porous implant.

Trauma to articular surfaces penetrating through the subchondral bone can result in areas of incomplete healing. Intraarticular adhesions can originate from these loci of disorganized fibrous bone and cartilage and, along with the incongruous surface, limit motion. In a group of 28 white New Zealand rabbits, 44 standard size defects were created in the prepatellar intercondylar femoral grooves. Twenty-seven were filled with Proplast, a porous implant material. Seventeen were left as controls. The animals were killed at intervals from 3 to 51 weeks. The implant areas were studied grossly and histologically. Granulation outgrowth and adhesions were not seen. From 12 weeks on, normal-appearing hyaline cartilage covered the surface, and bone ingrowth was found within the implant.

Animals↗
PubMed1979

Cruciate ligament stents in reconstruction of the unstable knee. A preliminary report.

Cruciate ligament stents have been developed to severe as internal splints which provide excellent temporary stability while allowing full range of motion of the knee during postreconstruction rehabilitation. Forty-three patients with disabling chronic knee instability were treated at one center using similar reconstruction techniques with either the anterior or posterior cruciate stent. When both cruciate ligaments were absent, only the posterior was used. All stents are intended only as temporary internal splints and all patients were advised that the structures were expected to break eventually. Followup of 15 patients with anterior cruciate stents revealed only 50% satisfactory overall results. Overall results were satisfactory in 80% of 20 patients with posterior cruciate stents. Longer implant survival is needed, and this must be accomplished by building more flexibility into the stent core and by improving surgical technique with more precise instrumentation.

Adolescent↗
PubMed1978

Use of plastipore for ossicular chain reconstruction: an evaluation.

With the exception of stapes prostheses, previous use of implantable alloplastic materials in reconstructing the sound conducting mechanism in middle ear surgery has been uniformly unsuccessful. A new material composed of ultra-high molecular weight polyethylene has been developed as a replacement for middle ear ossicles. This implant, called the Plastipore total ossicular replacement prosthesis (TORP), and the Plastipore drum to the stapes prosthesis were inserted in 87 patients, all of whom had a long history of extensive middle ear disease and/or surgery. One TORP patient was lost to follow-up. The overall average hearing gain was 14.8 db. The overall follow-up was 12.4 months with a range of from 3 to 25 months. Eleven of the 15 patients receiving the drum-to-stapes prosthesis had hearing gain; 55 of 71 patients receiving the TORP had hearing gain. Eight prostheses were extruded. Nine patients had no improvement in hearing. Eight patients had subsequent decrease in hearing after initial gains. All ears are now dry and aerated. Early evaluation appears to demonstrate that the Plastipore prosthesis shows promise for use in difficult reconstructive middle ear problems.

Ear Diseases↗