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Barry L Eppley

Publications and source records attributed to Barry L Eppley.

33 records · Page 2Linked to original sources
PubMed2004

Introduction of a novel internal spring-driven craniofacial bone distraction device.

A study of craniofacial bone distraction using an internal self-expanding bone device designed by the authors was performed in a young rabbit skull model. Ten 30-day-old New Zealand white rabbits were divided into two groups: 5 underwent distraction with the device, and 5 served as controls. Serial cephalograms, defleshed skull measurements, and histological examinations were performed on the study animals. The distracted group demonstrated a significant midface lengthening and overbite compared with the control group. Histologically, more fibroblasts and osteoblasts were seen in the front nasal bone in the distracted group in comparison with the nondistracted controls. The self-expanding internal bone distractor can effectively lengthen certain facial bones in an animal model and avoid some of the disadvantages associated with the external distraction techniques. This new device offers clinical potential as a useful distraction technique, but further work is needed to determine the effects of continuous postoperative tension loads on bone healing, the amount of tension generated by certain spring loads and lengths, and the feasibility of applying this concept in confined bone spaces.

Animals↗
PubMed2004

In vitro analysis of the elution of tobramycin from a calcium sulfate bone void filler.

The use of synthetic calcium-based bone replacements has a recent history in craniofacial surgery as a non- to minimally load-bearing graft substitute. Given its avascular nature at the time of placement, infection is an ever present risk. Antibiotics are often added to the material during surgery based on an empirical impression. Whether effective antibiotic release actually occurs and over what time are not known for many of the available calcium-based preparations. The purpose of this study was to investigate the release kinetics of tobramycin from molded cylinders of Calcigen S bone void filler (Biomet, Warsaw, IN) and to compare this with the release kinetics of tobramycin from plaster of Paris-based systems as reported in the literature. Calcigen S bone void filler is a form of calcium sulfate that is closely related to plaster of Paris yet remains distinct. In vitro studies as well as clinical series have demonstrated that plaster of Paris is an effective vehicle to deliver tobramycin in which therapeutic doses of the antibiotic are released after implantation. In vitro analysis of the elution of tobramycin from Calcigen S bone void filler substrate is similar to that of plaster of Paris.

Analysis of Variance↗
PubMed2004

Platelet quantification and growth factor analysis from platelet-rich plasma: implications for wound healing.

Growth factors released from activated platelets initiate and modulate wound healing in both soft and hard tissues. A recent strategy to promote the wound-healing cascade is to prepare an autologous platelet concentrate suspended in plasma, also known as platelet-rich plasma, that contains growth factors and administer it to wound sites. The purpose of this study was to quantitate platelet number and growth factors released from a prepared platelet concentrate. Whole blood was drawn from 10 healthy patients undergoing cosmetic surgery and concentrated into platelet-rich plasma. Platelet counts on whole blood and platelet-rich plasma were determined using a Cell-Dyn 3200. Platelet-derived growth factor-BB, transforming growth factor-beta1, vascular endothelial growth factor, endothelial growth factor, and insulin-like growth factor-1 were measured in the platelet-rich plasma using the enzyme-linked immunosorbent assay method. In addition, platelet activation during the concentration procedure was analyzed by measuring P selectin values in blood serum. An 8-fold increase in platelet concentration was found in the platelet-rich plasma compared with that of whole blood (baseline whole blood, 197 +/- 42 x 10 platelets/microl; platelet concentrate, 1600 +/- 330 x 10 platelets/microl). The concentration of growth factors also increased with increasing platelet number. However, growth factor concentration varied from patient to patient. On average for the whole blood as compared with platelet-rich plasma, the platelet-derived growth factor-BB concentration increased from 3.3 +/- 0.9 ng/ml to 17 +/- 8 ng/ml, transforming growth factor-beta1 concentration increased from 35 +/- 8 ng/ml to 120 +/- 42 ng/ml, vascular endothelial growth factor concentration increased from 155 +/- 110 pg/ml to 955 +/- 1030 pg/ml, and endothelial growth factor concentration increased from 129 +/- 61 pg/ml to 470 +/- 320 pg/ml. No increase was found for insulin-like growth factor-1. In addition, no increase in platelet activation occurred during the concentration procedure as determined by the platelet surface receptor P selectin (45 +/- 16 pg/ml to 52 +/- 11 pg/ml, p = 0.65). In conclusion, a variety of potentially therapeutic growth factors were detected and released from the platelets in significant levels in platelet-rich plasma preparations. Sufficient concentrates and release of these growth factors through autologous platelet gels may be capable of expediting wound healing in a variety of as yet undetermined specific wound applications.

Adult↗
PubMed2003

Hydroxyapatite cranioplasty: I. Experimental results from a new quick-setting material.

The biophysical characteristics of a new formulation of hydroxyapatite (HA) for craniofacial applications having a rapid set time was evaluated in animals. Using a mature rabbit model, the material was applied in both cranial defects and as a geometrically shaped cranial onlay. Visual and histological assessment was done after 1 year of implantation. The material remained morphologically stable after 1 year, with complete preservation of its onlay shape and stable fill of the cranial defects. A significant osteoconductive response was seen with bone growth across the inner and outer surfaces of the inlays and along the sides of the onlays. No fibrovascular ingrowth or bony replacement of the material itself was evident as a result of the age of the study animals or the compact density of the material. This rapid-setting HA formulation offers similar favorable tissue responses as those of other longer setting HA materials.

Age Factors↗
PubMed2003

The influence of temperature on the degradation rate of LactoSorb copolymer.

Heat is one of the fundamental forces that influence the rates of chemical reactions. The hydrolysis of an absorbable polymer is a function of many factors, both material-related and implant-site-related, including temperature. There is variance in temperature among patients as well as among various animals in which degradation studies are performed. This study investigated the influence of temperature on hydrolysis and found that a variance from 37 degrees C to as little as 2 degrees C can affect the rate of hydrolysis of a PGA/PLLA copolymer about 25-30%, with the rate increasing with increasing temperature. As most animals of biomedical interest have a body temperature on the order of 1-3 degrees C greater than that of humans, it is possible that animal testing may be "worst case"; that is, strength loss may be accelerated in animals relative to that in human patients. Also, variation of body temperature within the human population may contribute to some variance in the rate of hydrolysis from person to person; however, other influences may minimize this effect and make it difficult to observe clinically.

Absorbable Implants↗
PubMed2003

Hydroxyapatite cranioplasty: 2. Clinical experience with a new quick-setting material.

A clinical series of 62 patients who underwent cranioplasty using a new quick-setting hydroxyapatite (HA) material was done over a 2-year period. The majority of procedures (69%) were performed for secondary reconstruction of frontal, temporal, and supraorbital deficiencies after primary repair of a craniosynostosis. The frontal sinus was obliterated as part of the cranioplastic procedure in 5 cases (8%) in older patients. The material set effectively in approximately 5 minutes with a good working time. Infection occurred in 3 patients (5%) which was treated by removing the HA cranioplastic material. This faster-setting HA material offers similar cranioplastic benefits as other materials but with an accelerated intraoperative set time.

Adolescent↗
PubMed2002

Craniofacial impalement injury: a rake in the face.

Impalement injuries describe unusual objects and circumstances in which a body part is either partially embedded (one end sticking out) or transected (through-and-through) by a foreign material. In either case, the object remains as part of the wound and is highly conspicuous. These injuries are much more common on the trunk and extremities because of their larger surface areas and the relative ease in which the object may penetrate them without lethal consequences. In the face, however, such injuries are more rare because of protective reflexes that either move the face away from the coming object or permit it only to be deflected away without being embedded. In addition, the face presents a much smaller target than the rest of the body and, therefore, is more infrequently impaled. This paper presents a case that illustrates many of the classic features of the craniofacial impalement-type injury.

Adult↗
PubMed2002

The effect of therapeutic irradiation on LactoSorb absorbable copolymer.

Bioabsorbable implants continue to gain popularity in providing temporary internal fixation due to their many advantages over metallic internal fixation. Coincident with the presence of internal fixation devices, it may be necessary to use radiotherapy to treat tumors. While metal implants can alter the distribution of the radiotherapy beam, bioabsorbable polymer implants are, essentially, tissue equivalent. This ionizing irradiation, in sufficiently high dose, can affect polymers through chain scission and cross-linking and accelerate the hydrolysis of absorbable polymers. However, little is known about the effects of therapeutic doses on such materials. This study exposed LactoSorb (Biomet, Inc., Warsaw, IN) absorbable copolymer to doses of x-ray irradiation in a clinically relevant manner, in vitro, with individual doses of 2 Gy administered five days per week for up to eight weeks, yielding a total cumulative dose of up to 80 Gy. Specimens were tested both mechanically and for inherent viscosity. Overall, the LactoSorb specimens withstood exposure to the irradiation exceedingly well, providing empirical evidence of the suitability of this material for temporary internal fixation when subsequent radiotherapy in the region is probable.

Absorbable Implants↗
PubMed2002

Craniofacial reconstruction with computer-generated HTR patient-matched implants: use in primary bony tumor excision.

The aim of this clinical series is to report the effectiveness and safety of using computer-generated alloplastic hard tissue replacement (HTR) implants for the reconstruction of large defects of the cranio-orbital region when combined with simultaneous bone tumor excision. Seven patients who had large nonmalignant bony lesions of the anterior cranial vault and orbit underwent simultaneous bony excision and reconstruction with preoperatively fabricated custom alloplastic implants. Preoperatively, a 3D computed tomography (CT) scan was obtained from which an anatomical model was fabricated. On the anatomical model, the predicted amount of bone excision was performed. The defect in the model was then used to create an alloplastic (HTR polymer) implant for reconstruction and surgical placement. At the time of surgery, the implant was secured into position with either metal or resorbable plates and screws. In cases where the frontal sinus was in proximity to the implant, it was either cranialized and covered with a pericranial flap or obliterated with hydroxyapatite cement. All computer-generated implants required some modification intraoperatively due to a larger amount of bony excision than was preoperatively planned. This was accomplished by modifying the sterile back-up of the implant as an addition to the original implant or completing reconstruction of the bony defect with hydroxyapatite cement. All patients have healed uneventfully with a minimum of 1 year follow-up (average, 2.6 years). In all cases, excellent contours have been maintained and all patients have remained infection-free. In the management of large benign bony tumors of the cranio-orbital region, simultaneous reconstruction with custom implants fabricated from porous, hydrophilic HTR polymer can be preoperatively fabricated based on an estimate of the subsequent bony defect. The successful use of this approach depends on a favorable tissue quality of the recipient site, a generous preoperative estimate of the amount of bone that will be resected so that the implant is adequate, intraoperative techniques of expanding the implant reconstruction, and intraoperative methods to assure a partitioning of the implant from the frontal sinus.

Absorbable Implants↗
PubMed2002

Compartmentalized bone regeneration of cranial defects with biodegradable barriers--effects of calcium sodium phosphate surface coatings on LactoSorb.

In bony defects of the cranium, bone healing may be complicated by prolapse of surrounding tissue into the defect. This tissue acts as a potential obstruction to the migration of osteogenic cells, resulting in impaired bone formation. It has been shown in previous studies that when a membrane composed of resorbable polymers (LactoSorb) is placed over a cranial bone defect, it inhibits connective tissue from entering the wound and improves the rate and quality of the bony regenerate. This study is an extension of this work and specifically evaluated the effects of differing calcium-based surface coatings on membrane-covered cranial defects in the rabbit model. In non-critical size, full-thickness defects of the mature rabbit calvarium, four differently treated LactoSorb membranes were evaluated in each animal model over a 1-year postoperative period. The surface coatings (three treated, one untreated) consisted of a base-powdered material of calcium sodium phosphate (Osteostim, EBI, NJ), which were applied by different methods (pressed, brushed, one-sided versus two-sided). Evaluation consisted of cross-sectional histologic assessment of the cranial detects determining the quantitative bony fill and the presence of residual polymer material and calcium sodium phosphate. This study produced the following findings: (1) cranial defect regeneration occurs faster with calcium-coated membranes and is complete by 3 months; (2) no difference could be seen between the different methods of calcium sodium phosphate coating; (3) the calcium sodium phosphate coatings did not inhibit resorption of the biodegradable membranes for those systems that had coatings on one side; however, systems completely covered showed delayed resorption; and (4) the calcium sodium phosphate coatings did not produce any inflammatory reactions. These findings suggest that, in addition to inhibiting connective tissue from entering the wound site, the calcium coatings on resorbable devices may have beneficial effects in selected clinical conditions, especially in conditions where faster bone regeneration is necessary.

Absorbable Implants↗
PubMed2002

Cranial reconstruction with computer-generated hard-tissue replacement patient-matched implants: indications, surgical technique, and long-term follow-up.

The aim of this clinical study was to evaluate the effectiveness and safety of using computer-generated alloplastic (hard-tissue replacement) implants for the reconstruction of large defects of the upper craniofacial region. Fourteen patients who had large (> 150 cm2) preexisting defects of the cranium or cranio-orbital region underwent surgical reconstruction. Preoperatively, a three-dimensional computed tomographic scan was obtained from which an anatomic model was fabricated. The defect in the model was then used to create an alloplastic (hard tissue-replacement polymer) implant for reconstruction and surgical placement. At the time of surgery, the implant was secured into position with either metal or resorbable fixation. In cases where the frontal sinus was in proximity to the implant, the frontal sinus was either cranialized and covered with a pericranial flap or obliterated with hydroxyapatite cement. In cases that had been previously irradiated or infected, wide bony debridement and coverage with a vascularized muscle was initially performed, followed by implant reconstruction 6 months later. All implants fit easily into the bone defects, and only four (29 percent) required some minor adjustments to complete the fit. All patients healed uneventfully. With a minimum of 1 year follow-up (average, 3 years) in all cases, excellent contours have been maintained and all patients have remained infection-free. In large cranial defects, custom implants fabricated from porous, hydrophilic hard-tissue replacement polymer provide an exacting anatomic fit and a solid stable reconstruction. This method of reconstruction in these defects is rapid and exact, and significantly reduces operative time. Critical attention must be paid, however, to management of the frontal sinus and preexisting bone infection and the quality of the overlying soft-tissue cover.

Adolescent↗