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Biomedical subjects

E N Hanley

Publications and source records attributed to E N Hanley.

67 records · Page 4Linked to original sources
PubMed1985

Vascularization of tricalcium phosphate, an artificial bone substitute: preliminary observations.

Tricalcium phosphate (TCP), a biodegradable artificial bone substitute, was used to study the following questions: i) can TCP be vascularized; ii) do ectopically placed implants have osteoinductive capacity; and iii) does vascularization affect implant resorption? Implants were placed in dogs in several areas: i) subcutaneous controls; ii) wrapped with latissimus dorsi muscle; iii) wrapped in omentum; iv) saphenous and thoracodorsal av pedicles threaded through implant. Prior to harvest, animals were given tetracycline and implants were harvested at 3, 6, and 9 weeks. Microfil was injected prior to sacrifice and specimens were xeroradiographed. Histology and computerized axial tomography were obtained. From this study, we conclude that 1) TCP can be vascularized; 2) the most effective method of vascularization was by an AV pedicle threaded through the implant; 3) vascularized implants did not have osteoinductive properties per se, and 4) in the time observed no difference in implant resorption was demonstrated between the test groups.

Animals↗
PubMed1981

Comparative assessment of the early mechanical integrity of repaired tendon Achillis ruptures in the rabbit.

The effectiveness of closed versus open management of Achilles tendon ruptures was studied in a series of 40 adult rabbits. Tensile test data of tendon repair specimens excised after 10 weeks of equinus cast immobilization revealed stiffness and strength deficits, relative to uninjured contralateral tendons, ranging from 70 to 88%. Although no statistically significant differences in these early tensile properties were noted among groups managed conservatively versus those treated openly, the closed management group healed with length increases more than three times those which resulted from suture repair. Apposition of a small, longitudinal polytetrafluorethylene (Gore & Assoc., Newark, DE) patch graft in order to stimulate fibroblastic proliferation at the repair site had no biomechanical advantage over simple Kleinert suturing. The tensile test data were found to be consistent with the histological appearance of the repair sites and with detailed rupture dynamics patterns recorded by high-speed cinematography.

Achilles Tendon↗
PubMed1979

Bone stress: a radionuclide imaging perspective.

Thirty-five college athletes with lower leg pain underwent radiography and radionuclide studies to rule out a stress fracture. Their asymptomatic extremities and 13 pain-free athletes served as controls. Four main patterns were observed: (a) sharply marginated scintigraphic abnormalities and positive radiographs; (b) sharply marginated scintigraphic abnormalities and negative radiographs; (c) ill-defined scintigraphic abnormalities and negative radiographs; and (d) negative radionuclide images and negative radiographs. Since the patients with the first two patterns were otherwise identical medically, the authors feel that this scintigraphic appearance is characteristic of bone stress in the appropriate clinical setting, regardless of the radiographic findings. A schema is proposed to explain the occurrence of positive radionuclide images and negative radiographs in the same patient, using a broad conceptual approach to the problem of bone stress.

Adolescent↗
PubMed1978

Ferrographic analysis of wear particles in arthroplastic joints.

Analysis of aspirated synovial fluid appears to be a useful method for the study of the rates, mechanisms, and biological responses to wear in surgical joint replacements. Ferrography, an industrial technique of magnetic separation of particulate matter from samples of lubricating solutions, allows separation of wear debris from synovial fluid. Bichromatic microscopy and SEM X-ray analysis permit identification of metallic particles from arthroplastic joints. Polarized light microscopy characterizes and differentiates polyethylene and polymethacrylate debris. The number and morphology of the wear particles in synovial specimens from arthroplastic joints correlate with the rate and the mechanisms of wear, as confirmed by examination of the implant and the adjacent synovial tissue.

Color↗
PubMed1978

Failed lumbar disc surgery requiring second operation. A long-term follow-up study.

Forty-five patients who had lumbar disc surgery 10 or more years previously, and had required a second operative procedure, have been evaluated. Failures occurred up to 16 years after the first operation, and were most commonly due to pseudoarthrosis in the patients who underwent spinal fusion initially, and to recurrent disc lesions at the same level as previous surgery in the patients who did not have fusion. The clinical and functional results in the second group of patients who required a second procedure were comparable to those of patients who required only a single procedure. In contrast, patients who had undergone spinal fusion who required a second procedure had significantly worse clinical and functional results, both in comparison to the patients who did not undergo fusion as well as to patients who had had fusion as a single procedure. The only predictable, demonstrable source of failure was acquired spondylolysis. Frequently, repair of pseudoarthrosis did not lead to symptomatic relief. These data suggest that spinal fusion, when it fails, has a significantly worse prognosis than simple disc excision in the management of lumbar disc disease.

Adult↗
PubMed1978

Experimental fracture healing: evaluation using radionuclide bone imaging: concise communication.

Radionuclide bone imaging was performed in a rabbit model to observe the course of fracture healing and to establish criteria for distinguishing nonunion and delayed healing from normal healing. Sequential gamma-camera images (with pinhole collimator) were collected and subjected to computer analysis. Five groups were established: a) control--immobilization; b) control--immobilization plus periosteal stripping; c) simple fracture--osteotomy; d) delayed union--osteotomy plus periosteal stripping; and e) nonunion--osteotomy, periosteal stripping and polymethyl methacrylate interposed between fracture fragments. Histographic representation of absolute count rates along rabbit tibias followed a predictable pattern in the simple-fracture and delayed-union groups. They differed only in the time of appearance of phases. The nonunion group demonstrated no recognizable sequential pattern. In this experimental model, serial bone scanning with quantitative data analysis has shown potential for indicating the course of healing in fractures and for serving as a guide to treatment.

Animals↗
PubMedDate not supplied

Immunolocalization of MMP-19 in the human intervertebral disc: implications for disc aging and degeneration.

Matrix metalloproteinases (MMPs) degrade components of the extracellular matrix of the disc, but the presence of MMP-19 has not been explored. In other tissues, MMP-19 is known to act in proteolysis of the insulin-like growth factor (IGF) binding protein-3, thereby exposing this protein to make it available to influence cell behavior. MMP-19 also has been shown to inhibit capillary-like formation and thus play a role in the avascular nature of the disc. Using immunohistochemistry, normal discs from six subjects aged newborn through 10 years and 20 disc specimens from control donors or surgical patients aged 15-76 (mean age 40.2 years) were examined for immunolocalization of MMP-19; six Thompson grade I discs, five Thompson grade II, eight Thompson grade III, five Thompson grade IV, and one Thompson grade V discs were analyzed. The results indicate that in discs from young subjects, MMP-19 was uniformly localized in the outer annulus. In discs from adult donors and surgical patients, outer and inner annulus cells only occasionally showed MMP-19 localization. The greatest expression of MMP-19 was observed in young discs, and little expression was seen in older or degenerating discs. Because MMP-19 has been shown to regulate IGF-mediated proliferation in other tissues, its decline in the aging/degenerating disc may contribute to the age-related decrease in disc cell numbers.

Adolescent↗
PubMedDate not supplied

Cellular immunohistochemical localization of the matricellular protein myocilin in the intervertebral disc.

Myocilin is a 55-57-kDa protein that is a member of the olfactomedin protein family. It is expressed in the cornea, sclera and trabecular network of the eye, myelinated peripheral nerves, heart, skeletal muscle, trachea and other tissues. Myocilin binds to a domain of fibronectin, type IV collagen and laminen in the trabecular meshwork of the eye, and its expression is influenced by transforming growth factor beta. Because these extracellular matrix components also are common in the intervertebral disc, the objective of our study was to determine whether the matricellular protein myocilin could be detected in the human or sand rat intervertebral disc using immunohistochemistry and to assess its localization. We investigated 16 specimens of human disc tissue and discs from six sand rats. Three human disc cell cultures grown in three-dimensional culture also were evaluated. Immunocytochemical annulus analysis showed the presence of myocilin within the disc cell cytoplasm in some, but not all, cells. Extracellular matrix in both the human and sand rat disc was negative for myocilin localization. Myocilin is believed to play a role in cell-cell adhesion and/or signaling. Myocilin may have such functions within the disc cell population in a manner similar to tenascin, SPARC and thrombospondin, which are other matricellular proteins recently shown to be present in the disc.

Adult↗
PubMedDate not supplied

A comparison of radiographic findings in fusion and nonfusion patients ten or more years following lumbar disc surgery.

Ninety-six patients who had undergone disc excision and midline spinal fusion and 36 patients who had had simple disc excision had spinal radiographs made 10 or more years postoperatively. Claw spurs were found most commonly at the L2-3 and L3-4 levels in fusion patients, particularly male laborers. Traction spurs with segmental hypermobility were found more commonly at the L4-5 level in patients whose spines were not fused, particularly women. Total lumbar flexion-extension was greater in nonfusion than in fusion patients, but the L1-3 mobility was greater in those who had undergone fusion, suggesting a compensatory increase in the range of lumbar motion. Segmental mobility at levels of surgery in nonfusion patients was similar in those with good and those with poor clinical results. Disc space narrowing was common at levels of operation, but did not correspond to the clinical result. Pseudarthrosis was demonstrated in 26% of fusion patients, but was of no clinical significance. Although complex radiographic changes follow lumbar disc surgery, with or without failure, it is concluded that the plane radiograph is of little aid in determining the source of postoperative pain. The sole exception is that of acquired spondylolysis, which was found in 2.5% of this group of fusion patients, and was clearly associated with a poor clinical outcome. Symptomatic degenerative disc disease at levels above lumbar spinal fusions appears to be an uncommon clinical problem.

Female↗
PubMedDate not supplied

The musculoskeletal effects of smoking.

Currently, there are more than 50 million smokers in this country, and approximately 800 billion cigarettes are smoked each year. Smoking is now the leading avoidable cause of morbidity and mortality in the United States. According to one report, over 500,000 deaths per year in the United States alone can be attributed to smoking. For years, orthopaedic surgeons have known about the relationships that putatively exist between smoking and an array of orthopaedic conditions and complications. It has been shown to adversely affect bone mineral density, lumbar disk disease, the rate of hip fractures, and the dynamics of bone and wound healing. Although scientific and clinical information on smoking and its consequences suggests differing degrees of correlation between smoking and orthopaedic conditions, most available data do suggest a real and reproducible relationship. In the past, there have been many individual reports that deal with these relationships separately but very few published comprehensive reviews. This summary of the current literature regarding the relationship between smoking and musculoskeletal diseases and their treatment provides information that can be used clinically by both the practitioner and the patient.

Causality↗
PubMedDate not supplied

Accurate roentgenographic determination of lumbar flexion-extension.

Although many techniques have been devised for the roentgenographic measurement for angular motion in the lumbar spine, all present technical and visual problems. No previously described method has been subjected to a test of accuracy or reliability. A transparent plastic sheet technique provides a reproducible and accurate method for quantitative evaluation of flexion-extension motion in the lumbar spine.

Humans↗