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Biomedical subjects

B L Eppley

Publications and source records attributed to B L Eppley.

At least 91 records · Page 5Linked to original sources
PubMed1993

Experimental effects of intraorbital tissue expansion on orbitomaxillary growth in anophthalmos.

A skeletal growth study evaluating an intraorbital tissue expander as a globe replacement in anophthalmos was conducted in an infant animal model. Twenty-one 21-day-old kittens were equally divided into the following three groups: a control, a unilaterally enucleated, and an enucleated-expanded group. Postoperative three-dimensional computed tomographic scans were obtained at 5 months of age immediately before study termination. Linear orbital, orbitomaxillary, and zygomaticomaxillary dimensions were measured on the scans and compared at necropsy with orbital volume assessment on the dry skulls. Control animal orbits averaged 21.5 mm in height, 21.0 mm in width, and 5.1 cm3 in orbital volume, and an orbitomaxillary-zygomaticomaxillary height-to-width ratio of 31.0: 24.5. The control side, its contralateral side, and the contralateral orbits of the treated sides were not significantly different. By study completion, enucleation resulted in a significant loss of orbital volume (mean, 1.9 cm3; p < 0.001) confirmed by deficient orbitozygomaticomaxillary measurements. The expanded orbits showed no loss of volume (mean, 5.2 cm3; p > 0.1) and normalization of all linear midfacial structures. This study demonstrates that early expansion emanating from within the orbital soft tissue positively affects both the skeletal and lid anomalies associated with congenital globe loss or early enucleation.

Animals↗
PubMed1992

Use of postauricular skin grafts for vestibular reconstruction.

The use of full-thickness postauricular skin grafts for vestibular reconstruction is described. The procedure offers the advantages of a concealed donor scar, minimal patient discomfort and morbidity, ease of procurement, and confinement of the operations to a single region. Its use in 17 patients (31 grafts) resulted in complete take in 90.3% of the grafts. Maintenance of vestibular depth in most patients was maintained at 1-year follow-up. The disadvantages of the procedure are the limited amount of skin available and the need to suture the graft to the recipient site.

Ear, External↗
PubMed1992

Autologous facial fat transplantation: improved graft maintenance by microbead bioactivation.

An alternative approach to the management of free fat transplantation resorption was evaluated in a rat facial model. Fat grafts obtained from the inguinal region were transferred to subcutaneous lateral facial sites in 20 animals. The grafts were mixed with either basic fibroblast growth factor (bFGF) alone or dextran beads that had been pretreated with bFGF. The grafts were then compared by weight and histology at 1 and 6 months postoperatively. Although graft weights were nearly comparable at 1 month, substantial differences were seen at 6 months, with the bead-containing grafts exhibiting near complete weight maintenance and better overall graft form. Histologically, the bead-containing grafts had extensive intercellular collagen formation and a heterogeneity of adipocyte cell sizes, particularly after 1 month. These findings suggest that the addition of cell-specific bioactive peptides that affect either the preadipocyte cell line and/or the fibroblastic components of the recipient site improve postoperative fat graft weight maintenance. Delivery of the biochemical agent appears to require a carrier system to exert its effects.

Adipose Tissue↗
PubMed1992

A venous thrombosis technique for experimental thrombolytic therapy.

A technique for the experimental creation of a venous thrombus in the rat is described. This technique involves a circumferential stretching of the intima, which maximizes intraluminal collagen exposure without complete separation of the vessel wall. This thrombotic method was 94.4% effective at complete vessel occlusion after 24 hours in 40 treated veins. This model is of particular interest in the in vivo evaluation of thrombolytic agents in the laboratory setting and as an adjunct to thrombotic complications in microsurgery.

Animals↗
PubMed1992

Lower facial recontouring in craniofacial asymmetry.

The secondary correction of facial asymmetry due to early posterior cranial deformation is presented. The combination of mandibular skeletal reduction of the gonial angle and inferior border, masseter muscle thinning, and auricular setback can be an effective camouflage technique when the facial skeleton and occlusion do not require repositioning.

Child↗
PubMed1992

Effects of nerve growth factor on craniofacial onlay bone graft survival: preliminary findings.

A study was undertaken to evaluate the effects of nerve growth factor (NGF), which had previously demonstrated bone formation around mandibular nerve regenerates, on resorption of onlay bone grafts to the rabbit skull. Iliac grafts were onlayed on the parietal bone bilaterally and immobilized with wire ligatures in 15 animals. NGF and a control solution were introduced into the grafts through subcutaneous osmotic pumps. After 60 days, graft survival was compared by weights, histology, and fluorochrome labels. NGF-treated grafts were characterized by an average of 88.4% weight retention, preservation of the outer cortical plate with firm fixation to the underlying calvarium, and fluorescent labels localized to the inner cortex. Conversely, control grafts had an average weight retention of 42.8% (p < 0.01), nearly complete outer cortical plate loss with increased mobility of the residual inner cortex, and a lack of fluorescence in any part of the grafts. Despite the incongruous name, NGF exhibited a beneficial effect on onlay bone graft volume maintenance in this study. Although the mechanism and the long-term effects are unknown, inhibition of graft resorption rather than enhancement of bone formation is suggested.

Animals↗
PubMed1992

Effects of resorbable fixation on craniofacial skeletal growth: a pilot experimental study.

The effects of fixation composed of resorbable polymers on craniofacial development was investigated in an animal model. Fourteen rabbits had amalgam markers placed bilaterally at the lambdoid, coronal, and frontonasal sutures at 28 days of age. Seven animals (group I) were not plated and served as controls. The other 7 animals (group II) were fixed across the left coronal suture with a 4-hole, compressive resorbable plate. After 6 months, intermarker distances (growth) were measured radiographically, and the amount of fixation degradation was determined by extracted plate weights. Resorbable plating across the coronal suture resulted in local marker constriction adjacent to fixation. Compensatory lengthening of the distal aspect of the frontal bone occurred, however resulting in unaltered total cranionasal lengths compared with that of control animals. Plate degradation occurred with a mean decrease of 7% from their original weights. Molecular weight analysis of the plate differences, however, was not done. This initial study indicates that a large plate size and slow resorption properties of polymer fixation can have a similar restrictive effect on bone growth as that of metal fixation. Whether thinner plates or more rapidly resorbing polymers will permit normal growth in this animal model awaits further testing.

Animals↗
PubMed1992

Commissure stabilization appliance in facial reanimation surgery.

A modified maxillary appliance is described that provides an inexpensive intraoral method of commissure stabilization which effectively prevents transmission of stretching forces onto the delicate anastomoses and muscle insertion at the commissure and upper lip in the immediate and early postoperative period. It is well tolerated by the patient, does not interfere with eating, and may be carefully removed for periodic cleaning. It is a simple technique that adds an increased measure of flap security without any risk of morbidity.

Child↗
PubMed1992

Bioactivation of free-fat transfers: a potential new approach to improving graft survival.

A new approach to free-fat autotransplantation resorption was evaluated experimentally in a rat animal model. Bioactive fat grafts were created by the addition of basic fibroblast growth factor delivered by dextran beads to the grafts and compared with free fat alone, free fat plus beads, and free fat plus beads and a control solution in the same animal. The grafts were assessed by weight and histology at 1 and 12 months postoperatively in 40 animals. A graded response in weight retention was observed at 1 and 12 months, with the growth factor-treated grafts exhibiting near complete weight maintenance after 1 year. All other bead-containing grafts had an intermediate response, with free fat alone averaging more than one-half graft weight loss after 1 year. Histologically, the bead-containing grafts had good fibroblastic ingrowth, but extensive intercellular collagen formation and the occurrence of small-sized adipocytes among the larger adipocytes were seen only in the growth factor-treated grafts. These findings indicate that graft manipulations that affect the preadipocyte cells of the graft or fibroblastic components of the recipient site, either through polypeptide stimulation or surface charge attraction, may offer a viable approach to postoperative fat-graft volume maintenance.

Adipose Tissue↗
PubMed1992

The epigastric fat transfer: an alternative free flap model in the rat.

A free epigastric fat flap, a modification of the well-known cutaneous groin flap, is described in the rat. Vascular perfusion was successfully restored when transferred to the neck of the rat in 75% of the rats that underwent surgery, as assessed by multiple postoperative stripping tests and select microangiography. This flap offers the advantages of familiar anatomy, ease of postoperative care without risk of flap trauma, and a challenge to microsurgical technique development for successful flap transfer execution. Therefore, this free flap provides an additional animal model for use in microsurgical training as well as a research tool in fat transplantation physiology.

Abdominal Muscles↗
PubMed1991

A physicochemical approach to improving free fat graft survival: preliminary observations.

A different experiment approach to the problem of post-transplantation free fat graft resorption was evaluated. Bioactive free fat grafts were created through the addition of basic fibroblast growth factor (bFGF) carried on positively charged, hydrophilic, dextran beads to the grafts. This bioactive graft was compared with contralateral free fat grafts in the lateral facial areas of mature rats. After 90 days, when compared with the body mass increase of the animals, complete retention of the bioactive fat grafts occurred in contrast to the free grafts that exhibited loss of nearly half of their original weight. The histologic findings of small-sized adipocytes or adipocyte buds among larger adipocytes in the bioactive grafts raise the possibility of activation and induced differentiation of a preadipocyte cell line in these grafts.

Adipose Tissue↗
PubMed1991

Computerized digital enhancement in craniofacial cephalometric radiography.

Application of digital radiologic imaging techniques to cephalometric assessment of the craniofacial skeleton is presented. Digital-enhanced and standard cephalometric radiographs were compared by osseous and soft tissue landmark analysis. Although both radiographic methods exhibited comparable accuracy at identifying bony landmarks, digital enhancement was consistently superior at delineating soft tissue relationships.

Cephalometry↗
PubMed1991

Efficacy of nerve growth factor in regeneration of the mandibular nerve: a preliminary report.

An experimental study evaluating the potential utility of nerve growth factor (NGF) on sensory nerve regeneration was conducted in a rabbit mandibular nerve model. In 10 animals, bilateral 7-mm nerve gaps were created and repaired with the placement of 10-mm Silastic (American Scientific Products, McGaw Park, IL) conduits into which NGF (left side) and a control solution (cytochrome C, right side) was instilled. After 90 days, the nerve repairs were removed and the two sides compared by clinical appearance, and histologic and electrophysiologic assessment. The conduits instilled with control solution failed to result in nerve regeneration in any of the animals. The conduits with NGF solution, however, consistently displayed neural connections between the proximal and distal ends with the presence of slowed, but recordable, conduction velocities. The axonal numbers in the NGF repairs were significantly less than those of the normal nerve, but when adjusted for fascicular size, the axonal densities were comparable. In addition, osteoid tissue was observed around many of the NGF-induced nerve regenerates, but not on the control solution side, suggesting a possible influence of this protein on bone formation.

Animals↗