An experimental study of the effects of craniofacial growth on the long-term positional stability of microfixation

A Narrative Review of u-HA/PLLA, a Bioactive Resorbable Reconstruction Material: Applications in Oral and Maxillofacial Surgery

The advent of bioresorbable materials to overcome limitations and replace traditional bone-reconstruction titanium-plate systems for bone fixation, thus achieving greater efficiency and safety in medical and dental applications, has ushered in a new era in biomaterial development. Because of its bioactive osteoconductive ability and biocompatibility, the forged composite of uncalcined/unsintered hydroxyapatite and poly L-lactic acid (u-HA/PLLA) has attracted considerable interest from researchers in bone tissue engineering, as well as from clinicians, particularly for applications in maxillofacial reconstructive surgery. Thus, various in vitro studies, in vivo studies, and clinical trials have been conducted to investigate the feasibility and weaknesses of this biomaterial in oral and maxillofacial surgery. Various technical improvements have been proposed to optimize its advantages and limit its disadvantages. This narrative review presents an up-to-date, comprehensive review of u-HA/PLLA, a bioactive osteoconductive and bioresorbable bone-reconstruction and -fixation material, in the context of oral and maxillofacial surgery, notably maxillofacial trauma, orthognathic surgery, and maxillofacial reconstruction. It simultaneously introduces new trends in the development of bioresorbable materials that could used in this field. Various studies have shown the superiority of u-HA/PLLA, a third-generation bioresorbable biomaterial with high mechanical strength, biocompatibility, and bioactive osteoconductivity, compared to other bioresorbable materials. Future developments may focus on controlling its bioactivity and biodegradation rate and enhancing its mechanical strength.

Safety of Contemporary Resorbable Fixation Systems for Craniofacial Reconstruction in Pediatric Patients

BACKGROUND

Resorbable hardware allows adequate strength for maintaining the relative position of the craniofacial skeleton during osseous healing, and allowing subsequent growth in pediatric patients. The purpose of this study was to determine the complication profile of the latest copolymer of resorbable plates for craniofacial reconstruction in pediatric patients.

METHODS

Retrospective query of the operative billing record was performed for use of the DePuy Synthes Rapidsorb Fixation System at the authors' tertiary children's hospital from 2015 to 2019. Three hundred twenty-five patients were randomly selected for analysis of complications within the first postoperative year.

RESULTS

Median age at craniofacial reconstruction was 3.0 years, with 127 procedures (39.9 percent) performed for an intracranial mass and 141 procedures (44.3 percent) performed for craniosynostosis. Overall, 7.9 percent patients had a postoperative wound complication. The most common complications were dehiscence (3.8 percent), hematoma/seroma (3.5 percent), and infection (2.5 percent). There were no instances of extrusion, plate fracture, or screw loosening. Hardware complications in the temporoparietal region were more likely to occur at incision sites (p = 0.001), whereas wound complications at the frontal region were more likely to occur away from incision sites (p < 0.001). There were no differences in complications between plates secured with resorbable screws or with the resorbable injectable polymer system (p ≥ 0.161 for all). Radiotherapy was significantly implicated in development of clinical infection (p = 0.001), culture-positive infection (p < 0.001), readmission (p = 0.007), reoperation (p = 0.003), and plate removal (p = 0.007).

CONCLUSION

Resorbable cranial hardware has an overall favorable complication profile for craniofacial reconstruction in pediatric patients undergoing surgical intervention for craniosynostosis or intracranial mass resection.

Infant ossified cephalohematoma: a review of the surgical management and technical update

Cephalohematoma is a subperiosteal collection of blood above the skull. It is associated with operative and prolonged deliveries. In most cases the hematoma spontaneously resolves in a short span of time, usually within one month. In a few cases cephalohematoma can become ossified and require surgical treatment. Traditional belief that ossified cephalohematomas are an exclusively cosmetic issue has been called into question by recent description of EEG anomalies associated to a calcified cephalohematoma. We review relevant surgical literature, and we describe a novel variant of Wong's Radial Cap technique by foregoing healthy bone margin removal, removing the cephalohematoma lamellae in a stepwise fashion and using resorbable plaques for fixation. We furthermore review the rationale, timing and step-by-step execution of the procedure. An exemplary case description is discussed.

Clinical Evaluation of an Unsintered Hydroxyapatite/Poly-L-Lactide Osteoconductive Composite Device for the Internal Fixation of Maxillofacial Fractures

Introduction:

OSTEOTRANS MX (Takiron Co, Ltd, Osaka, Japan) is a resorbable osteosynthetic material composed of an unsintered hydroxyapatite/poly-l-lactide composite, and its osteoconductive capacity has been documented. The authors here report their clinical experience using OSTEOTRANS MX.

Methods:

The authors treated 35 patients (19 men, 16 women; age, 14–88 years; mean ± standard deviation, 38.4 ± 19.9 years) with maxillofacial fractures. The authors used standard surgery to stabilize fractures in all patients, fitting resorbable plates (thickness, 1.0 or 1.4 mm) and screws (diameter, 2 mm) according to Arbeitsgemeinschaft für Osteosynthesefragen/Association (AO) for the Study of Internal Fixation guidelines.

Results:

All patients eventually achieved satisfactory healing with favorable restoration of form and function without foreign body reaction. Complications occurred in 3 patients—plate exposure in 2 and discomfort in 1. However, fracture sites healed in all patients. Scanning electron microscopy revealed that the devices bonded directly to the bone without interposition of nonmineralized tissue.

Conclusion:

OSTEOTRANS MX is a useful material with few complications. Its osteoconductive bioactivity is advantageous for the early functional improvement of maxillofacial fractures.

The Efficacy of Bioabsorbable Mesh in Craniofacial Trauma Surgery

Background

The ultimate goal of craniofacial reconstructive surgery is to achieve the most complete restoration of facial functions. A bioabsorbable fixation system which does not need secondary operation for implant removal has been developed in the last decade. The purpose of this study is to share the experience of authors and to demonstrate the efficacy of bioabsorbable mesh in a variety of craniofacial trauma operations.

Methods

Between October 2008 and February 2015, bioabsorbable meshes were used to reconstruct various types of craniofacial bone fractures in 611 patients. Any displaced bone fragments were detached from the fracture site and fixed to the mesh. The resulting bone-mesh complex was designed and molded into an appropriate shape by the immersion in warm saline. The mesh was molded once again under simultaneous warm saline irrigation and suction.

Results

In all patients, contour deformities were restored completely, and bone segments were fixed properly. The authors found that the bioabsorbable mesh provided rigid fixation without any evidence of integrity loss on postoperative computed tomography scans.

Conclusion

Because bioabsorbable meshes are more flexible than bioabsorbable plates, they can be molded and could easily reconstruct the facial bone in three dimensions. Additionally, it is easy to attach bone fragments to the mesh. Bioabsorbable mesh and screws is effective and can be easily applied for fixation in various craniofacial trauma reconstructive scenarios.

Dental materials for cleft palate repair

Numerous bone and soft tissue grafting techniques are followed to repair cleft of lip and palate (CLP) defects. In addition to the gold standard surgical interventions involving the use of autogenous grafts, various allogenic and xenogenic graft materials are available for bone regeneration. In an attempt to discover minimally invasive and cost effective treatments for cleft repair, an exceptional growth in synthetic biomedical graft materials have occurred. This study gives an overview of the use of dental materials to repair cleft of lip and palate (CLP). The eligibility criteria for this review were case studies, clinical trials and retrospective studies on the use of various types of dental materials in surgical repair of cleft palate defects. Any data available on the surgical interventions to repair alveolar or palatal cleft, with natural or synthetic graft materials was included in this review. Those datasets with long term clinical follow-up results were referred to as particularly relevant. The results provide encouraging evidence in favor of dental and other related biomedical materials to fill the gaps in clefts of lip and palate. The review presents the various bones and soft tissue replacement strategies currently used, tested or explored for the repair of cleft defects. There was little available data on the use of synthetic materials in cleft repair which was a limitation of this study. In conclusion although clinical trials on the use of synthetic materials are currently underway the uses of autologous implants are the preferred treatment methods to date.

Are Biodegradable Osteosyntheses Still an Option for Midface Trauma? Longitudinal Evaluation of Three Different PLA-Based Materials

The aim was to evaluate three different biodegradable polylactic acid- (PLA-) based osteosynthesis materials (OM). These OM (BioSorb, LactoSorb, and Delta) were used in 64 patients of whom 55 (85.9%) had fractures of the zygoma, five (7.8%) in the LeFort II level, two of the frontal bone (3.1%), and two of the maxillary sinus wall (3.1%). In addition to routine follow-up (FU) at 3, 6, and 12 months (m) (T1, T2, and T3) all patients were finally evaluated at a mean FU after 14.1 m for minor (e.g., nerve disturbances, swelling, and pain) and major (e.g., infections and occlusal disturbances) complications. Out of all 64 patients 38 presented with complications; of these 28 were minor (43.8%) and 10 major (15.6%) resulting in an overall rate of 59.4%. Differences in minor complications regarding sensibility disturbance at T1 and T3 were statistically significant (P = 0.04). Differences between the OM were not statistically significant. Apart from sufficient mechanical stability for clinical use of all tested OM complications mostly involved pain and swelling probably mainly related to the initial bulk reaction attributable to the drop of pH value during the degradation process. This paper includes a review of the current aspects of biodegradable OM.

Screw implantation in the globe: the risk of delayed hardware migration from craniofacial repair

Plating system modification has enabled the use of rigid fixation in younger patients having maxillofacial surgery. One of the common reported complications of the use of plates and screws in children is screw migration due to skeletal maturation. Ophthalmic complications due to maxillofacial surgery reported to date include oculomotor and abducens palsies, lacrimal damage and vision loss due to infection, retrobulbar hemorrhage, and compartment syndrome. We describe a complication unique to screw migration resulting in orbital fixation and near-globe rupture in a patient with Treacher Collins syndrome. We hope to alert our colleagues to the potential risk of screw and hardware migration and breakage, particularly in the setting of craniofacial surgery performed on a child before maturation of craniofacial osseous structures.

[Implant materials for the internal fixation of midfacial fractures]

The material used for osteosynthesis plays a crucial role in the management of facial fractures. Plates need to be flexible enough to be bent and should not be palpable through the skin, while ensuring stable fixation und adequate biocompatibility. Although stainless steel was initially the material of choice, titanium has become the standard material due to its superior biocompatibility. While the explantation of titanium plates and screws appears unnecessary in general, it should be considered in cases of dislocation, cosmetic concerns, pain and infection. Due to their limited initial stability and a potential increase in local complications, resorbable materials based on polymeric lactose are used with caution in midfacial fractures in adults. Our own retrospective study comparing the postoperative complications after fixation of lateral midfacial fractures with titanium and resorbable systems demonstrated a low complication rate for both systems (7-8%) and no statistically significant difference between the two. The appropriate material for fixation should be selected based on the localization and severity of the fracture, the experience of the surgeon as well as on the age and overall condition of the patient.

Evolution of Operative Techniques for the Treatment of Single-Suture Metopic Synostosis

PURPOSE

Primary orbitocranioplasty for metopic craniosynostosis encompasses a variety of techniques, with variable long-term success. The authors present a series illustrating the evolution of surgical techniques and its impact on surgical outcomes.

METHODS

All patients with single-suture metopic synostosis treated at the Children's Hospital of Philadelphia from 1975-2004 were included. Demographic information, preoperative clinical findings, operative technique, postoperative complications, postoperative clinical findings, and length of follow-up were all recorded. Five techniques are presented, reflecting a transition from mere reshaping with metallic fixation to the increased use of primary bone grafting and resorbable fixation to expand the frontal region. Preoperative covariates and technique type were analyzed for effect on outcomes.

RESULTS

Eighty-six patients were identified. Mean follow-up was 50 months. In terms of esthetic outcome, patients with preoperative frontal irregularities had a higher incidence of postoperative deformities (P = 0.026). Patients with preoperative mean intercanthal distance <20 had a higher incidence of postoperative frontal irregularities (P = 0.045). Maximal expansion of the supraorbital bar via interpositional bone graft and stabilization of the construct with strategic bone grafting and resorbable fixation resulted in a lower incidence of postoperative temporal hollowing (P = 0.029). Patients with expansion and lateral reinforcement of the expanded bar had a lower incidence of reoperation (P = 0.026).

CONCLUSIONS

Undercorrection of metopic craniosynostosis is not an uncommon finding. To prevent long-term relapse, aggressive anterolateral expansion of the supraorbital bar via primary bone grafting and resorbable fixation with the overall goal of overcorrection may provide the best esthetic outcome.

Síntese e caracterização do copolímero poli (L-co-D,L Ácido Láctico)

A aplicação de polímeros biorreabsorvíveis em próteses temporárias é constante nos procedimentos médicos relacionados a fraturas ósseas. Dentre os polímeros bioreabsorvíveis, o poli(L-co-D, L ácido láctico), PLDLA, na relação 70:30, tem sido estudado visando à obtenção de placas e parafusos para a recuperação de traumas nas regiões buco e crâniomaxilofacial. Nessa relação de monômeros obtém-se um polímero amorfo, o que permite uma adaptação do dispositivo ao local do implante durante a cirurgia. Um fator limitante para o uso desse polímero é seu alto custo em função da importação. Neste trabalho o PLDLA foi sintetizado através da polimerização em massa dos monômeros cíclicos do L-ácido láctico e do D, L ácido láctico, utilizando como catalisador o Sn(Oct)2. Obteve-se material de alta massa molar (Mw = 10(5) g/mol), o qual foi caracterizado por ¹H RMN, 13C RMN, GPC, FTIR e DSC.

The use of biodegradable plates and screws to stabilize facial fractures

PURPOSE

The purpose of this preliminary retrospective study was to review the demographics and outcome of patients with a variety of facial fractures that were stabilized with PL bone plates and screws.

MATERIALS AND METHODS

The records of 295 consecutive patients with facial fractures treated by open reduction and internal fixation, performed by the author from 2001 through 2004, were retrospectively reviewed. Patients were selected to receive biodegradable fixation on the basis of mechanism of injury, the degree of bony displacement demonstrated on clinical and radiographic examination, patient age, and fracture pattern or location. Outcome measures such as infection, non-union, and mal-union were identified and subjectively assessed. Descriptive statistics were recorded and analyzed.

RESULTS

Two hundred eighty-one patients met the criteria for inclusion in the study with follow-up of 3 weeks to 3 years. Fifty-nine (21%) patients were identified as having received biodegradable plates and screws. All patients eventually went on to satisfactory healing with favorable restoration of form and function. Complications occurred in 16 patients overall (6%). Of these, 2 patients were treated with resorbable plates and screws; 1 patient with a zygomatico-maxillary complex fracture developed a sterile abscess that presented 1 year postoperatively and responded to local measures. Another patient with a Le Fort I fracture developed an anterior open bite necessitating Le Fort I osteotomy for correction.

CONCLUSIONS

Favorable healing can be observed through the use of biodegradable PL plates and screws to stabilize selected midface fractures in patients of all ages, as well as mandible fractures in early childhood.

Les matériels d'ostéosynthèse résorbables

There is continued interest in the development of new biomaterials. The application of new implantable biomaterials requires intense research and thorough evaluation. Much time and effort has been required to overcome the risks and problems associated with the bioabsorbable devices. For surgical bone fixation, these materials were investigated since the 1960's. Different polymer properties were explored to ensure adequate strength and biocompatibility. High-molecular-weight bioabsorbable polymers were initially used, followed by addition of reinforcement materials. The most recent materials are self-reinforced, small yet strong devices. The newer generations contain bioactive substances such as antibiotics and growth factors. Bioabsorbable materials are constantly changing as we try to adopt the principles of tissue engineering. Surgeons are using new techniques to exploit these polymers and their bioabsorbable properties. It is hoped that this multidisciplinary approach of surgery and research will continue to help the further evolution of biomaterial science.

The Pediatric Mandible: II. Management of Traumatic Injury or Fracture

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Describe the changing epidemiology of mandibular fractures in children and adolescents. 2. Discuss the appropriate use of internal fixation in the treatment of pediatric mandibular fractures. 3. Describe the difficulties posed by the deciduous dentition in the use of interdental wiring. 4. Understand reasons why techniques specific to adult fractures may not be applicable to the growing mandible. 5. Understand the etiology and epidemiology of pediatric mandibular fractures. 6. Understand the reasons for conservative (closed) versus aggressive (open) treatment of mandibular injury.

BACKGROUND

Fractures of the pediatric mandible are complicated by the anatomic complexity of the developing mandible, particularly by the presence of tooth buds and the eruption of deciduous and permanent teeth. Traditional methods of fracture reduction and fixation employed in adults have little applicability in the pediatric population.

METHODS

The authors describe the surgical techniques that have been used at their institution and those that can be used safely in the pediatric setting.

RESULTS

In most cases, "conservative" management is the preferred option, especially in the treatment of condylar fractures. In cases requiring surgical intervention, interdental wiring, drop wires in combination with circummandibular wires, and acrylic splints are suited well to specific phases of dental maturation.

CONCLUSION

Open reduction and internal fixation using monocortical screws and microplates or resorbable plates and screws are acceptable techniques in the pediatric patient, but they require special safeguards. Algorithms are presented to simplify management of these complicated injuries.

Spotlight on naturally absorbable osteofixation devices

The practice of using implants is growing day by day, and more foreign materials are being inserted for various indications. The field of implantology thus deserves intensive research and careful evaluation of results. Solutions to overcome current problems and risks are necessary. It has taken a long time to arrive at where we are now. Bioabsorbable devices were explored in the 1960s for surgical bone fixation. Failures were followed by changes in ways of thinking and innovations. Improvements in the strength properties and biocompatibility were achieved. Bioabsorbable polymeric materials such as high-molecular-weight polymers were used and also reinforced with other material or, more recently, by self-reinforcement to produce small yet strong devices. New generations of implants include those that contain bioactive substances such as antibiotics and growth factors. Developments in bioabsorbable materials continue to accommodate the new way of thinking brought about by the emergence of the field of tissue engineering. Surgeons, conversely, are also inventing new surgical techniques and methods to exploit the plastic and bioabsorbability properties of these materials for the better future of our patients. Such a multidisciplinary approach that involves surgeons and materials scientists should help to find solutions to the current limitations of these devices.

Intracranial migration of fixation wires following correction of craniosynostosis in an infant

BACKGROUND

In the craniofacial skeleton, osseous fixation techniques for stabilization include stainless steel wire, miniplates or bioresorbable plates; in some cases, stainless steel wires are still indicated. Most recently, several case reports have demonstrated that microplates or stainless steel wires migrate intracranially when used in the craniofacial skeleton in neonates.

PATIENT

We present the case of a 7-year-old male who underwent treatment of brachycephaly at the age of 5 months. In this patient, internal migration of wires was observed.

CONCLUSION

In our opinion, there is a difference between migration of wires and of plates in the growing cranium. Factors affecting the incidence of material migration in cranioplasty are believed to include (1) age, (2) site and (3) the material itself.

The use of bioabsorbable osteofixation devices in craniomaxillofacial surgery

Because of problems associated with the conventional osteofixation devices used in craniomaxillofacial surgery, bioabsorbable devices have presented an appealing alternative. Devices made of the polymers polyglycolide (PGA) and polylactide (PLA) and their copolymers (PLGA and PLDLA) are currently the most commonly used. Strong implants can be manufactured from these polymers with a self-reinforcing technique and used in the treatment of fractures and osteotomies. Self-reinforced devices have been studied for nearly 2 decades by our multidisciplinary research group for internal fixation of the bone in both experimental and clinical settings. In craniomaxillofacial fractures and osteotomies they have been used for as long as 10 years with no significant clinical problems. Because of more favored degradation characteristics, currently the copolymer devices (PLDLA and PLGA) represent the advancing front in the application of absorbable devices in craniomaxillofacial surgery. By using bioabsorbable devices, several problems associated with conventional biostable devices can be avoided, especially in children. New techniques that are not possible with biostable devices can be developed by using bioabsorbable devices, too. Our experience with and research on self-reinforced devices are shared here.

Resorbable plate fixation in pediatric craniofacial surgery: long-term outcome

OBJECTIVE

To determine the long-term efficacy of resorbable plate fixation in pediatric patients undergoing craniofacial surgery for congenital anomalies, traumatic deformities, or skull base tumors.

DESIGN

Retrospective case review.

MATERIALS AND METHODS

Medical records of 57 consecutive cases using resorbable plates and screws for craniofacial fixation in patients younger than 18 years were analyzed.

MAIN OUTCOME MEASURES

The status of bone healing postoperatively (anatomical union, malunion, delayed union, or nonunion) and any complications or adverse effects (hardware visibility or palpability, plate extrusion, or infection) were noted.

RESULTS

In midfacial and upper face procedures (54 patients) anatomical union and uncomplicated bone healing occurred in 52 (96%) of the patients. In this same group, complications (plate extrusion) occurred in 2 patients (3.7%) and were resolved using conservative treatment without untoward sequelae. These outcomes are comparable to results using metal osteosynthesis in similar situations. Costs of resorbable hardware are similar to existing metal fixation systems.

CONCLUSIONS

Our data support the use of bioresorbable plate fixation in pediatric craniofacial surgery as a means of avoiding the potential and well-documented problems with rigid metal fixation. Indications include fractures and segmental repositioning in low-stress non-load-bearing areas of the middle and upper craniofacial skeleton. Although there is an initial learning curve in using this technology, we believe the benefits are well worth the effort and represent a major advance in pediatric craniofacial surgery.

Developments in craniomaxillofacial surgery: use of self-reinforced bioabsorbable osteofixation devices

Because of the problems associated with the conventional osteofixation devices used in craniomaxillofacial surgery, absorbable devices present an appealing alternative. Devices made of the polymers polylactide, polyglycolide, and their copolymers (PLGA and P[L/DL]LA) are currently the most commonly used. Ultrahigh-strength implants can be manufactured from these polymers with the self-reinforcing technique. Over the authors' almost two decades of study, both in experimental and clinical settings, self-reinforced devices have proved to be biocompatible, easy to handle, and mechanically strong, even for the fixation of femoral neck fractures. In craniomaxillofacial surgery, the authors have used self-reinforced devices for over 8 years without complications. Because of the more favored degradation characteristics, currently the copolymeric self-reinforced devices (P[L/DL]LA, Biosorb FX and PLGA, Biosorb PDX; Elite Performance Technologies, Solana Beach, Calif.) represent the advancing front in the application of absorbable devices in craniomaxillofacial surgery. The authors' share their experience and their studies of self-reinforced devices, which possess the highest strength and ductility of all bioabsorbable products.

Long-term follow-up of dynamic cranioplasty for brachycephaly--non-syndromal bicoronal synostosis

We followed up 10 patients whose non-syndromal bicoronal synostosis had been operated on with a dynamic cranioplasty technique developed by this craniofacial unit in 1992. With this technique, the growth of the brain is redirected in an anteroposterior direction as wire-mediated compression and restraint are exerted on the transverse and vertical dimensions of the skull. The mean operating time was 160 minutes (range 120-275) and mean stay in the intensive care unit was 36 hours (range 23-58). There was no operative mortality and few complications. The surgical results were assessed objectively by analysis of cephalometric tracings. The mean (SD) cephalic index was 87.6 (4.9) preoperatively and 77.7 (1.8) postoperatively (p = 0.001). The modified Whitaker scale was used as a subjective outcome measurement, and nine patients were classified as Whitaker grade 1 (no additional surgery). One patient required additional intracranial surgery. A questionnaire was sent to all families to obtain an additional subjective measurement of outcome. Parents' satisfaction was high. We conclude that dynamic cranioplasty is a safe and efficient operation for treatment of brachycephaly.