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Biomedical subjects

Barry L Eppley

Publications and source records attributed to Barry L Eppley.

At least 19 recordsLinked to original sources
PubMed2006

Injectable soft-tissue fillers: clinical overview.

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Know the composition and biology of injectable fillers. 2. Understand the advantages and disadvantages of each injectable filler. 3. Understand the U.S. Food and Drug Administration regulatory status of each type of injectable filler, including their indications. BACKGROUND: The use of injectable filling agents for soft-tissue facial defects has a long history of successful use based on xenogeneic collagen materials. New materials of differing compositions for injection treatments either are now available or will soon be available for clinical use. METHODS: A review of the medical literature was performed to provide chemical compositions, methods of preparation, biological behavior, and clinical outcomes for every known injectable filler material that is either currently used or being evaluated in clinical trials. RESULTS: Hyaluronic acid-based materials have now replaced animal or human-derived collagen as the standard injection materials. Synthetic alternatives offer the potential of longer lasting results, but the long-term outcome with their use in large numbers of patients is not yet known. CONCLUSIONS: As there is no single injectable filler that has all of the desired characteristics, understanding the advantages and disadvantages of one filler over another is extremely helpful in guiding the patient to an informed decision. Although all of the reviewed injectable fillers are safe, the concepts of their long-term volume persistence and how they compare with each other remain largely anecdotal, with few prospective controlled clinical trials.

Biocompatible Materials↗
PubMed2006

Stability of craniofacial PLLA/PGA copolymer bioabsorbable screws.

The behavior of bioabsorbable plates and screws after implantation is a dynamic process that results in dimensional changes of the devices after surgery. Bioabsorbable plates frequently are recognized as changing because of their size, but bioabsorbable screws are less appreciated in this regard. How bioabsorbable screws may change after placement and whether their manufacturing method has an influence on size and shape after implantation needs further study. Using 1.5-mm diameter screws made of an oriented copolymer of 82% poly-L-lactic acid and 18% polyglycolic acid (LactoSorb copolymer), screw dimensions were measured before and after soaking in an in vitro pH 7.4, 37 degrees C buffer environment. After 33 days of exposure to buffer, there were no changes in the physical appearance of the screws, and there was no change in dimensions or shape. The orientation of polymer materials in a bioabsorbable screw device improves its strength and can retard the rate of hydrolysis. However, the residual stresses in oriented screws theoretically can potentiate dimensional shift in the implants during hydrolysis. That such shift did not occur during the early phase of hydrolysis provides further evidence of the mechanism by which these types of screws can maintain biomechanical function throughout the bone-healing phase of the craniofacial skeleton.

Absorbable Implants↗
PubMed2006

Platelet-rich plasma: a review of biology and applications in plastic surgery.

Healing of hard and soft tissue is mediated by a complex array of intracellular and extracellular events that are regulated by signaling proteins, a process that is, at present, incompletely understood. What is certain, however, is that platelets play a prominent if not deciding role. Controlled animal studies of soft and hard tissues have suggested that the application of autogenous platelet-rich plasma can enhance wound healing. The clinical use of platelet-rich plasma for a wide variety of applications has been reported; however, many reports are anecdotal and few include controls to definitively determine the role of platelet-rich plasma. The authors describe platelet biology and its role in wound healing; the preparation, characterization, and use of platelet-rich plasma; and those applications in plastic surgery for which it may be useful.

Animals↗
PubMed2006

A resorbable rivet system for pediatric craniofacial surgery: biomechanical testing and clinical experience.

The use of a new method of bone fixation for pediatric craniofacial surgery was evaluated by both biomechanical tests and clinical use. A "pull-back" rivet composed of 82% poly-L-lactic acid and 18% polyglycolic acid (LactoSorb) for use with resorbable plates was developed to obviate the traditional hand-tapping technique used for the placement of resorbable screws. In in vitro testing, the average failure load of the rivets in uniaxial pullout was nearly 50 kg and approximately 75 kg in shear. Approximately two thirds of their initial strength was retained by 6 weeks. In clinical testing, 10 patients undergoing cranial vault reconstruction were treated by 1.5-mm resorbable plates secured by rivets. Although postoperative clinical outcomes were unaffected, good engagement of the devices with secure plate fixation was obtained in only about 70% of the rivets fired. Although the novel approach of a pull-back rivet was encouraging in both design and in vitro testing, its clinical use is impaired by the sensitivity of the device to the thickness of the bone into which it is placed, as well as its larger diameter compared with resorbable screws.

Absorbable Implants↗
PubMed2006

The effect of high temperature intraoperative molding on bioabsorbable PLLA-PGA craniofacial fixation.

Bioabsorbable internal fixation has become an established part of the surgeons' armamentarium. There are several unique aspects of bioabsorbable polymers that can enhance their versatility. One of these is the application of heat to adapt the implant. Hot-tip cautery has been used for years to cut and otherwise customize bioabsorbable implants intraoperatively. As the tips of these devices can reach temperatures of over 1,000 degrees C, there is the potential that such practice can modify the degradation properties of these polymers. This study was performed to better understand the extent to which this potential exists. Screw heads of an 82:18 poly-L-lactic acid and poly-glycolic acid copolymer were modified by repeated passage of a hot-tip cautery wire, deforming the hex geometry to that of a ball. There was no significant difference between the glass transition temperature (approximately 59 degrees C) and inherent viscosity (approximately 1.45 dL/g) of treated and untreated screw heads, indicating no overall change in these properties throughout the mass of the screw head. Additionally, these properties were measured and comparisons made between the treated screw heads and untreated plates made of the same polymer during 28-day exposure to an in vitro bath (pH 7.4, 37 degrees C). The glass transition temperature and inherent viscosity exhibited declines during this period, with no significant differences between the two groups. Collectively, these results suggest that hot-tip cautery results in no substantial changes in the degradation characteristics of this polymer.

Absorbable Implants↗
PubMed2006

Treatment of nasopharyngeal stenosis by prosthetic hollow stents: Clinical experience in eight patients.

OBJECTIVE: A series of nasopharyngeal appliance designs is presented that represents our evolving experience over a 20-year period in the adjunctive use of prosthetic stents in the surgical correction of nasopharyngeal stenosis. DESIGN: Retrospective assessment of effectiveness of two nasopharyngeal stenosis hollow stent designs in a consecutive series of patients for relief of nasal obstructive symptoms. SETTING: Tertiary academic medical center, Craniofacial Program at Children's Hospital. PATIENTS: Four patients with nasopharyngeal stenosis were treated with a preoperatively fabricated stent made from a clasped palatal appliance onto which hollow acrylic conduits were extended through surgically re-created pharyngeal ports. A subsequent set of four patients with nasopharyngeal stenosis were treated with intraoperatively-fashioned silastic grommets, as opposed to palatal appliances. INTERVENTIONS: Postoperative intraoral stenting of nasopharyngeal ports. MAIN OUTCOME MEASURES: Maintenance of pharyngeal port opening after 1 year, improvement in nasal airway obstructive symptoms. RESULTS: The palatal appliance stents were less well tolerated and had a lower maintenance of port patency after device removal (4 of 8, 50%). The silastic grommets provided better retention into the ports and increased patient tolerance, as well as better 1-year port maintenance (6 of 8, 75%). CONCLUSIONS: The grommet stent appliance offers numerous advantages over a conventional dental-clasped appliance for prosthetic nasopharyngeal stenting, including obviation of extensive preoperative preparation, ease of insertion and removal, and exchange of air during the stenting period. Improved nasopharyngeal patency with this device may be due to greater patient tolerance and subsequent longer use.

Adolescent↗
PubMed2005

Use of resorbable plates and screws in pediatric facial fractures.

PURPOSE: The use of resorbable plates and screws for fixation of pediatric facial fractures is both well tolerated and effective. It enables realignment and stable positioning of rapidly healing fracture segments while obviating any future issues secondary to long-term metal retention. PATIENTS AND METHODS: Forty-four pediatric facial fractures were treated over a 10-year period at our institution using differing techniques of polymeric bone fixation. Twenty-nine mandible fractures in patients under the age of 10 (age range, 6 months to 8 years) were treated. Displaced fractures of the symphysis, parasymphysis, body, and ramus underwent open reduction and either 1.5-mm or 2.0-mm plate and screw fixation in 14 patients. Subcondylar fractures were treated by a short period of maxillomandibular fixation (3 weeks) achieved with suture ligation between resorbable screws placed at the zygoma and symphysis or a circummandibular suture attached to a zygomatic screw. Fifteen patients (age range, 4 to 11 years) with isolated frontal, supraorbital, intraorbital, or orbitozygomatic fractures were treated by open reduction and internal fixation with 1.5-mm resorbable plates, mesh, and screws. RESULTS: No long-term implant-related complications were seen in any of the treated patients. CONCLUSIONS: Resorbable polylactic and polyglycolic acid plates and screws can be an effective fixation method for facial fractures in children in the primary and secondary dentition periods.

Absorbable Implants↗
PubMed2005

Three-dimensional osteotomy planning in maxillofacial surgery including soft tissue prediction.

Preoperative planning of complex osteotomies in craniomaxillofacial surgery, in conjunction with a surgeon's expertise, is essential for achieving an optimal result. However, the soft tissue changes that accompany facial bone movements cannot yet be accurately predicted. Bony tissue, because of its greater density, can be better predicted, but it alone does not account for the final aesthetic result. A new approach using not only three-dimensional (3-D) surface models of the patient's anatomy, but also a corresponding volumetric model, is discussed. This 3-D planning software was used in the treatment of 15 patients and was found to provide a good correlation between simulation and postoperative outcome.

Adipose Tissue↗
PubMed2005

Biomechanical testing of alloplastic PMMA cranioplasty materials.

Alloplastic cranioplasty techniques using polyfmethylmethacrylate (PMMA) are a common method of restoring lost cranial bone. Numerous compositions of PMMA exist for this application, using either intraoperatively cured solid compositions or preoperatively fabricated porous custom implants. Although all of these PMMA materials feel solid by palpation, the amount of cranial protection that they provide has never been precisely evaluated. Whether differences exist between the differing PMMA cranioplasty materials likewise is unknown. An impact resistance test was performed on uniform-size blocks of differing PMMA materials of representative cranial thickness using American Society of Testing and Materials (ASTM) method D 3029-78. Based on mean failure weights of 3.9 lb (Cranioplast), 4.2 lb (Cranioplexx), and 4.0 lb (HTR polymer), all of these materials are comparatively the same in impact resistance. Precured porous PMMA, despite having 30% to 40% less material, offered no less impact resistance. Based on projections to cranial bone, PMMA materials appear to offer protection similar to that of native osseous tissue.

Biomechanical Phenomena↗
PubMed2005

Antibiotic elution from hydroxyapatite cement cranioplasty materials.

Hydroxyapatite cements (HAC) are a contemporary material used for multiple cranioplasty applications. In an effort to decrease the risk of postoperative infection, mixing antibiotics into the material during intraoperative application is frequently done. It has been assumed, but never substantiated, that significant antibiotic release from the material occurs after implantation. Using standardized morphologies, a mixture of a specific HAC (Mimix bone void filler) and tobramycin antibiotic was prepared, hydrated in phosphate-buffered saline, and tested in vitro for as long as 22 days after preparation. The results show that the majority of the antibiotic (91%) was released within the first 24 hours, with the balance being eluted during the next 8 days. Overall, the release of tobramycin from Mimix bone void filler appears to fit the pattern of antibiotic release demonstrated to occur from other bioabsorbable ceramic-type carriers.

Anti-Bacterial Agents↗
PubMed2005

Donor site morbidity of rib graft harvesting in primary alveolar cleft bone grafting.

The use of the rib for primary alveolar cleft bone grafting offers one of the few donor sites for grafting under one year of age. Its use in 211 patients in an 11 year period revealed no morbidity other than a small donor scar. Rib grafting in infants differs significantly from that in teenagers and adults with minimal pain, no risk of pneumothorax when properly performed, and more than an adequate stock of bone for the alveolar defect.

Alveolar Process↗
PubMed2005

The spectrum of orofacial clefting.

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Describe the differing types of congenital clefting defects that extend outward from the perioral region. 2. Define the sites of anatomical disruption and deformities that these types of facial clefts cause. 3. Describe the cause and incidence, if known, of orofacial clefts and their inheritance/transmission risks. BACKGROUND: Clefts of the orofacial region are among the most common congenital facial defects. The clinical presentation is usually that of a lateral cleft of the lip through the philtrum with or without extension through the palatal shelves. However, atypical forms of clefts with lip involvement also occur in a variety of patterns, some of which are embryologically predictable; others are not. METHODS: An overview of the embryology, cause, and incidence of this diverse and interesting group of congenital orofacial clefts is presented. RESULTS: Clefts involving the lateral upper lip; median upper lip; and oblique facial, lateral facial, and median mandibular regions are reviewed. CONCLUSIONS: This review of orofacial malformations describes clefting anomalies that emanate from the mouth and lips. As the causes of orofacial clefts are better understood, it is becoming clear that a complex interplay between genetic and environmental variables causes these clefts. Future study of orofacial clefts will require increasingly sophisticated methods of elucidating these subtle interactions.

Abnormalities, Multiple↗
PubMed2005

Craniosynostosis anomalies in twins.

This report discusses the incidence of twinning in nonsyndromic and syndromic craniosynostosis. Nonsyndromic craniosynostosis occurs in approximately 1 in 2,100 live births; the incidence of twinning in patients with nonsyndromic craniosynostosis has been reported to be higher than the rate of 2.5% of live births in the general population. No definitive explanation for this increased risk is known. The incidence of twinning in patients with nonsyndromic craniosynostosis may range between 2.5 and 19 in 210,000 live births. Syndromic craniosynostosis occurs in between 1 per 10,000 live births (Muenke's syndrome) to 1 per 80,000 live births (Apert's syndrome). Because of the these low occurrences, the actual incidence of twinning in syndromic craniosynostosis is difficult to predict. A theoretical incidence between 2.5 per million live births in Muenke's syndrome and 2.5 per 8 million live births in Apert's syndrome can be estimated.

Craniosynostoses↗
PubMed2005

Surgical technique for primary alveolar bone grafting.

Bone grafting of the alveolar cleft is an important component of the comprehensive care of the cleft lip and palate patient. Although debate exists regarding the optimal timing of the procedure, one approach is the placement of a rib graft in the alveolar cleft before eruption of the deciduous canine (primary alveolar bone graft). Since 1982, primary alveolar bone grafting has been performed at our institution in more than 300 patients. Because little is reported in the literature on primary alveolar bone grafting in general, an experienced surgical technique and protocol are lacking. Our surgical technique for rib graft harvest as well as alveolar bone graft placement in the infant cleft alveolus is described.

Alveolar Process↗
PubMed2005

Allograft and alloplastic bone substitutes: a review of science and technology for the craniomaxillofacial surgeon.

Bone healing is a complex and multifactorial process. As such, there are numerous steps in the process to which intervention can be directed. This has given rise to many bone graft technologies that have been used to regenerate bone, creating, perhaps, a bewildering array of options. The options that surgeons have the most familiarity with are the ones that have been available the longest (i.e., autograft and allograft). Although useful for the widest spectrum of clinical applications, limitations of these grafts has prompted the development of new materials. Demineralized bone matrix formulations and synthetic ceramic materials are now being used with greater frequency. These biomaterials have demonstrated their usefulness in facial plastic and reconstructive surgery with their ability to augment and replace portions of the craniofacial skeleton. The purpose of this article is to describe and discuss the allograft and alloplastic bone grafting technologies so that the reader can consider each in the context of the others and gain a better appreciation for how each fits into the universe of existing and emerging treatments for bone regeneration.

Biocompatible Materials↗
PubMed2005

Platelet rich plasma: biology and new technology.

Platelets play a central role in hemostasis and wound healing. The latter is mediated by release of secretory proteins on platelet activation, which directly or indirectly influences virtually all aspects of the wound healing cascade. Studies in basic science have shown a dose-response relationship between the platelet concentration and levels of secretory proteins, as well as between platelet concentration and certain proliferative events of significance to the healing wound. Technologies to provide autologous platelet rich plasma to the repair site are now being used in a wide variety of clinical applications, with the majority of such studies suggesting a role in the surgeon's armamentarium. Little standardization in the field exists, which has made it difficult to fully evaluate the literature on the subject and unequivocally establish applications for which the technology truly has merit. This article presents fundamental background on platelet biology and the role of platelets in both hemostasis and wound healing, as well as methods of preparing, characterizing, and using platelet rich plasma, to provide the reader a foundation on which to critically evaluate prior studies and plan future work.

Biology↗
PubMed2004

Resorbable PLLA-PGA plate and screw fixation in pediatric craniofacial surgery: clinical experience in 1883 patients.

The need to provide rigid bony fixation in the surgical treatment of craniofacial deformities has inspired an on-going evolution of surgical innovations and implants. Because of the young age of many treated craniosynostosis patients and the unique pattern of cranial vault growth, the extensive implantation of metal devices is potentially problematic. The use of resorbable plate and screw devices offers all of the benefits of rigid fixation without many of their potential risks. Since the introduction of resorbable plate and screw devices in 1996, tens of thousands of craniofacial patients have received implants, but long-term results from a large series have yet to be reported. A combined prospective and retrospective analysis was done on 1883 craniosynostosis patients under 2 years of age treated by 12 surgeons from seven different geographic locations over a 5-year period who used the same type of resorbable bone fixation devices (poly-L-lacticpolyglycolic copolymer). Specifically, the incidence of postoperative infection, fixation device failure, occurrence of delayed foreign-body reactions, and the need for reoperation resulting from device-related problems were determined. Technical difficulties and trends in device use were also noted. From this series, significant infectious complications occurred in 0.2 percent, device instability primarily resulting from postoperative trauma occurred in 0.3 percent, and self-limiting local foreign-body reactions occurred in 0.7 percent of the treated patients. The overall reoperation rate attributable to identifiable device-related problems was 0.3 percent. Improved bony stability was gained by using the longest plate geometries/configurations possible and bone grafting any significant gaps across plated areas that were structurally important. The specific types of plates and screws used evolved over the study period from simple plates, meshes, and threaded screws to application-specific plates and threadless push screws whose use varied among the involved surgeons. This report documents the safety and long-term value of the use of resorbable (LactoSorb) plate and screw fixation in pediatric craniofacial surgery in the infant and young child. Device-related complications requiring reoperation occurred in less than 0.5 percent of the implanted patients, which is less frequent than is reported for metallic bone fixation. Resorbable bone fixation for the rapidly growing cranial vault has fewer potential complications than the traditional use of metal plates, screws, and wires.

Absorbable Implants↗