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Biomedical subjects

B L Eppley

Publications and source records attributed to B L Eppley.

At least 73 records · Page 4Linked to original sources
PubMed1994

Effects of a positively charged biomaterial for dermal and subcutaneous augmentation.

Based on previous experimental connective tissue work, the use of a positively charged dextran-based biomaterial in subcutaneous tissue sites was evaluated. After hydration with saline, the biomaterial was injected beneath the abdominal skin in rats. A robust macrophage response was initially seen at 30 days without acute inflammation. By one year postoperatively, extensive intermaterial fibroblast and collagen ingrowth had occurred. No evidence of a foreign-body or chronic inflammatory response was seen. These preliminary findings suggest good tissue compatibility of this biomaterial and suggests that when combined with a biocompatible liquid medium, the potential for development of a bioactive dermal and subcutaneous injectable substance exists.

Animals↗
PubMed1994

A potential biomaterial composite for dermal and subcutaneous augmentation.

Based on previous experimental connective tissue work in cutaneous wound healing, cell culture, and fat transplantation, the use of positively charged dextran beads for subcutaneous and dermal augmentation was evaluated. When combined with a biocompatible liquid medium, the material easily flowed through small-gauge needles. When injected beneath the facial skin in rats, a profound macrophage response was initially seen at 30 days accompanied by fibroblast proliferation and new collagen formation. By 1 year, a quiescent noninflammatory cellular response with extensive intermaterial collagen deposition was evident. No adverse reactions were seen in the contralateral facial sites, which were injected with only the liquid medium. These preliminary findings suggest good tissue compatibility of this composite biomaterial and provide further evidence of the significant regulatory role of the macrophage in the tissue response to implanted biomaterials.

Animals↗
PubMed1994

Mechanical anastomosis of nerves: a histological and functional comparison to conventional suturing.

The use of a mechanical coupling device in microsurgery offers speed of application in addition to a secure vascular union. Despite its success in a vascular setting, mechanical coupling device nerve repair remains to be studied. Forty-five male rats were tested over 7- and 14-week study periods. One half of the animals underwent primary suture repairs for transected sciatic nerves, and the remainder of the animals had their nerves repaired using a mechanical coupling device. Postoperative analysis consisted of histological evaluation of pre- and postrepair site nerve morphology (axonal continuity and counts) as well as functional testing using walking track analysis. Mechanical coupling device coaptation of the nerves using the epineurium was done in approximately one half the time compared with conventional suturing. After both 7 and 14 weeks postoperatively, walking track analysis showed no difference in the amount of functional return between the two repair groups. No animal exhibited complete return of function. Axonal continuity occurred across both repairs without significant difference in their pre- and postrepair axonal counts. Although no clear advantage was seen in this study, the concept of mechanical nerve coupling merits further investigation based on its potential clinical utility.

Anastomosis, Surgical↗
PubMed1994

Biomechanical comparison of wire osteosynthesis techniques in craniofacial surgery.

The biomechanical stability of 20 different craniofacial wire osteosynthesis methods were tested in a simulated bone model. Utilizing wire fixation across a curved osteotomy site of an acrylic bar fixed at one end, compressive loading at the suspended end was used to test the resistance of the ligatures to stretch failure. Twenty-eight- and 30-gauge ligature patterns tested included single loops, double loops, and figure-eights across both 1- and 2-cm distances. A two-way analysis of variance was then used to determine the various effects of wire diameter, configuration, and loop length. The extensional deformation of ligature fixation was shown to be reduced by increasing the number of wire loops, reducing intraloop distances, or employing a slightly larger gauge diameter. The complex wiring configuration of a figure-eight technique was of no advantage over simple wire loops. In comparative strengths, two double loops were stronger than one double loop, and two single loops were stronger than one single loop or figure-eight. Comparable reductions in fixation strength were seen in all groups; there were larger intrabony distances between the burr holes or with the smaller gauge wire. These biomechanical ligature testing results are useful in those craniofacial skeletal sites where the use of more rigid fixation is either contraindicated or not desired.

Analysis of Variance↗
PubMed1994

Effects of resorbable fixation on craniofacial skeletal growth: modifications in plate size.

On the basis of previous experimental work in young rabbits, modifications in the polymer fixation used (i.e., smaller plate size, change in ratio of polymer components) were studied for potential alleviation of known growth restriction in this model. Ten juvenile rabbits with metallic markers placed at the calvarial sutural junctions were plated across the left coronal suture. At 6 months of age, measurements were taken of both intermarker distances radiographically (growth) and the plates directly. Unlike previous reports, these resorbable plates permitted symmetrical frontal bone development, unaffected growth across the coronal suture, and a histologically normal underlying suture. These changes appear to be the result of elongation of the fixation plate across a growth site. These results indicate that the change in shape of resorbable fixation after initiation of degradation is more important than complete degradation of the material in rapidly growing bone sites.

Animals↗
PubMed1994

Cranial reconstruction in osteogenesis imperfecta.

Although osteogenesis imperfecta (OI) is recognized as a cause of craniosynostosis, therapeutic endeavors have not been reported. We present an 8-month-old girl with type 3 OI, in whom bilateral occipital flattening, biparietal widening, and frontal narrowing were effectively managed with a combined surgical release and reconstruction and molding cap therapy. The quality of the calvarial bone in OI requires a modified approach to the conventional bone techniques commonly used in the correction of craniosynostosis deformities.

Craniosynostoses↗
PubMed1994

Systemic effects of photothermolysis of large port-wine stains in infants and children.

Fifteen patients who were 5 years of age or younger with large port-wine stain lesions were studied after flashlamp pulsed-dye laser therapy. Matched serum haptoglobin assays were obtained immediately prior to and after the laser treatments intraoperatively. Combined with the testing for hemosiderin from urine samples collected within 2 hours postoperatively, the amount of intravascular hemolysis present after early photothermolysis was assessed. Mean preoperative haptoglobin levels were within normal ranges (116 +/- 13 mg/dl), which then averaged a 9.5 percent decrease (105 +/- 8 mg/dl) at the conclusion of laser therapy. The decline in haptoglobin levels was higher in the youngest patient but did not exceed the renal threshold for hemoglobin. No evidence of hemoglobin was found in the urine or urine sediment of any patient. These results indicate that although hemoglobinemia does occur after port-wine stains ablation with the flashlamp pulsed-dye laser, the level of intravascular hemolysis obtained is not injurious to the infant or child with large cutaneous involvement. Flashlamp pulsed-dye laser therapy, therefore, may be undertaken safely at very young ages to obtain maximum clinical and psychological benefit.

Child, Preschool↗
PubMed1994

Effects of primary alveolar bone grafting on maxillofacial development in the rabbit.

Unilateral maxillary clefts were created in 4-week-old rabbits by removing premaxillary-maxillary sutures. Four groups, five animals per group, were formed. Control animals (Group I, no clefts) helped determine normal values for facial growth. In Group II the clefts were unrepaired. In Group III each had a rib graft harvested and placed into the alveolar defect only. In Group IV the cleft was completely grafted with multiple ribs to the nose. At six months postoperatively skeletons of all animals were directly measured and an orthogonal coordinate analysis compared maxillary and palatal growth among groups. Greatest deviations in growth were seen when the entire cleft was grafted; shortened maxillary development and nasal deflection to the clefted side occurred. Unrepaired clefts and grafts limited to the alveolus had maxillofacial development similar to that in unoperated controls. The location of grafts in clefts in infancy appears critical to avoid retarded maxillary growth.

Alveolar Process↗
PubMed1994

Surgical correction of metopic suture synostosis.

Premature fusion of the metopic suture is an uncommon form of craniosynostosis, historically reported with an incidence of less than 10% among the various forms of craniosynostoses. Despite its infrequency, it is the most obvious deformity associated with premature fusion of a single suture with its prominent frontal keel, narrow forehead, and close-set eyes. This article discusses the timing, long-term results, and recent advances of surgical techniques.

Child, Preschool↗
PubMed1994

Mandibular vascular malformations: treatment and long-term results.

Two cases of intraosseous vascular anomalies of the mandible--including surgical treatment and 10-year follow-up--are reported. Early aggressive resection not only resulted in resolution of symptoms and restoration of facial symmetry but also exhibited significant osseous regeneration without grafting.

Arteries↗
PubMed1994

Negatively charged resins stimulate bone formation in subperiosteal sites in rats. The effect of age.

The osteogenic response to subperiosteal injection of negatively charged ion exchange resins was compared in the tibiae of one-month and 16- to 22-month-old rats. The resins were administered either in the form of beads (CM Sephadex) or as particles (CM cellulose, carboxymethylcellulose), and the animals were killed at two weeks and at one month after injection. Histologically, the resins did not produce an inflammatory response. Periosteal bone formation was observed wherever resin was in contact with bone, and in the resin bed the connective tissues that invested the charged materials ossified within the first month. Marrow spaces commonly formed where periosteal growth was most rapid. The osteogenic effect was independent of resin conformation, and it was more pronounced in the younger rats.

Aging↗
PubMed1993

Enhancement of repair in experimental calvarial bone defects using calcium sulfate and dextran beads.

Granular medical-grade calcium sulfate hemihydrate (MGCSH) and negatively charged dextran beads (DB) were evaluated both separately and in combination in cranial defects. Thirty-six rats received bilateral parietal inlay reconstructions using MGCSH, MGCSH plus DB, or DB alone or the defects were left unfilled. Postoperative evaluation at 45, 90, and 135 days was done by visual inspection, caliper measurements of defect thickness, and histologic examination. The best fibro-osseous repair of the defects occurred with the use of MGCSH in combination with DB. Repair tissue, which was confluent with the adjacent cranium, was noted to have good thickness, and a high bone content. By contrast, defects repaired with either DB or MGCSH alone had poorer quality repair tissue, with concavities, voids, bead migration, decreased thickness, and minimal bony replacement/ingrowth. Unfilled control defects showed only a thin, friable, translucent connective tissue layer of repair. No method produced complete bony closure.

Animals↗
PubMed1993

Effects of skeletal fixation on craniofacial imaging.

The imaging effects of high-density scatter from different metal compositions of plate and screw fixation systems were assessed in cadaveric craniomaxillofacial skeletons with computed tomographic scanning. Differences in image clarity of three-dimensional reconstructions were observed between titanium, stainless steel, and cobalt-chromium-molybdenum alloy onlay fixation systems, which were not significantly altered with or without an overlying soft-tissue density (facial drape). These differences were reduced in a plaster model, in which the plates were in an intrabony location.

Artifacts↗
PubMed1993

Experimental effects of bone plating in infancy on craniomaxillofacial skeletal growth.

The potential effects of mini- and microfixation on craniofacial development was investigated in an animal model. Twenty-four rabbits had amalgam markers placed bilaterally at the lambdoid, coronal, and frontonasal sutures at 28 days of age. In group 1, plating was not done and served as controls. In groups 2 to 4, single 2- and 4-hole microplates and 4-hole miniplates were fixed across the left coronal suture. The right suture was not plated. After 6 months, intermarker distances and craniofacial angles were measured radiographically. Coronal sutures underneath the plates were also histologically evaluated. Plating across the coronal suture resulted in local anteroposterior constriction of marker distances that did not differ with the type of fixation used. More distant markers, however, were increased in all specimens as a compensation and, as a result, the cranionasal length of all groups were similar. No change in craniofacial angles was observed from that of the controls. Sutural morphology on the side of fixation was altered with decreased widths, cellular numbers, and bone deposition. These experimental results demonstrate that early plate application in a normal calvarium results in local growth restriction that can be overcome by regional bone growth compensation.

Analysis of Variance↗
PubMed1993

Correction of secondary cleft lip and nasal deformities.

Surgical techniques for the correction of commonly seen secondary cleft deformities of the lip and nose are reviewed. These techniques include revision of the vermilion, vermilion--cutaneous junction, philtrum, nasal base, and nasal tip. Timing of intervention and coordination with other orofacial therapies are emphasized.

Abnormalities, Multiple↗