Distraction Osteogenesis of the Mandible With an Internal Bioresorbable Device

External mandibular distraction in unusual pediatric syndromes with micrognathia and airway obstruction

Mandibular hypoplasia is a craniofacial malformation that can cause airway obstruction and may affect the eating process. This anomaly is common in many polimalformed Syndromes, including the Pierre Robin Sequence and the Moebius Syndrome. It is also common in cases related to the dysgenesis of the brainstem. In order to avoid tracheostomy, or to allow for early decannulation in severely affected children, external distraction devices were employed in 3 clinical cases to repair mandibular deficiencies. A successful external mandibular distraction induces the removal of the airway obstruction, allowing spontaneous ventilation without devices, an independent eating process with no need of nasogastric or gastrostomy tubes, apart from the linguistic and facial asymmetry improvement.

Bioabsorbable fixation devices in trauma and bone surgery: current clinical standing

Bioabsorbable fixation devices are increasingly used in trauma, orthopedic and craniomaxillofacial surgery. The devices are essentially made of polylactic acid and/or polyglycolic acid polymers. Ultra-high-strength implants are manufactured from such polymers using self-reinforcing techniques. Implants are available for stabilization of fractures, osteotomies, bone grafts and fusions, as well as for reattachment of ligaments, tendons, meniscal tears and other soft tissue structures. As these implants are completely absorbed, the need for a removal operation is overcome and long-term interference with tendons, nerves and the growing skeleton is avoided. The risk of implant-associated stress shielding, peri-implant osteoporosis and infections is reduced. Implants do not interfere with clinical imaging. Current clinical use of bioabsorbable devices is reviewed.

Pediatric Craniofacial Surgery: A Review for the Multidisciplinary Team

Pediatric craniofacial surgery is a specialty that grew dramatically in the 20th century and continues to evolve today. Out of the efforts to correct facial deformities encountered during World War II, the techniques of modern craniofacial surgery developed. An analysis of the relevant literature allowed the authors to explore this historical progression.

Current advances in technology, tissue engineering, and molecular biology have further refined pediatric craniofacial surgery. The development of distraction osteogenesis and the progressive study of craniosynostosis provide remarkable examples of this momentum. The growing study of genetics, biotechnology, the influence of growth factors, and stem cell research provide additional avenues of innovation for the future. The following article is intended to reveal a greater understanding of pediatric craniofacial surgery by examining the past, present, and possible future direction. It is intended both for the surgeon, as well as for the nonsurgical individual specialists vital to the multidisciplinary craniofacial team.

Mandibular distraction in a tracheostomized patient with Pierre-Robin sequence

The triad of glossoptosis, micrognathia, and cleft palate characterizes the Pierre Robin sequence (PRS). Complications can be severe and the clinical manifestations are very heterogeneous, but airway obstruction is almost present and may be life threatening. To avoid tracheostomy or allow for early decannulation in severely affected children, external or bioresorbable internal distraction devices can be applied to repair mandibular deficiencies. We report a case of a children submitted to bilateral mandibular distraction with external nonresorbable devices. After optimal lengthening of mandibles, laryngotracheoplasty was performed to close the tracheostomy with improvement of respiratory pattern and quality of life this child. Bioresorbable internal distraction devices offers some advantages, but complications include device failure to support resistance. Distraction osteogenesis has become a safe, less-invasive procedure with a negligible risk of infection making it effective to substitute tracheostomy as first choice in treatment of patients with Pierre Robin Sequence and life threatening airway obstruction.

Meta-analysis of mandibular distraction osteogenesis: clinical applications and functional outcomes

BACKGROUND

Mandibular distraction osteogenesis has been used effectively to treat syndromic craniofacial deformities. In recent years, its scope of application has widened to include treatment of airway obstruction in adults and children and nonsyndromic class II mandibular hypoplasia. So far, there has been no evidence-based review of mandibular distraction osteogenesis for mandibular lengthening.

METHODS

Two rounds of searches were performed by two independent assessors. The first-round PubMed search used the keywords "mandible" and "distraction osteogenesis." In the second-round search, the reference lists of the articles were retrieved. For both rounds, abstracts and then full articles were reviewed and selected on the basis of a set of inclusion and exclusion criteria.

RESULTS

The 178 retrieved articles yielded 1185 mandibular distraction osteogenesis patients: 539 received unilateral mandibular distraction osteogenesis and 646 received bilateral mandibular distraction osteogenesis. Mandibular distraction osteogenesis was reported to improve facial asymmetry and retrognathia (50.1 percent), correct the slanted lip commissure (24.7 percent), and improve or level the mandibular occlusal plane (11.1 percent) in unilateral asymmetry cases, whereas bilateral mandibular distraction osteogenesis was shown to be effective in preventing tracheostomies for 91.3 percent of neonates or infants with respiratory distress, and in relieving symptoms of obstructive sleep apnea for 97.0 percent of children and 100 percent of adult patients.

CONCLUSIONS

Mandibular distraction osteogenesis is effective in treating craniofacial deformities, but further clinical trials are required to assess the long-term stability and to compare the treatment with conventional treatment methods, especially in cases of obstructive sleep apnea or class II mandibular hypoplasia.

The Use of Internal Maxillary Distraction for Maxillary Hypoplasia: A Preliminary Report

PURPOSE

Distraction osteogenesis is a useful alternative to advance the maxilla in complicated cases of maxillary hypoplasia. The purpose of this article is to review the workup, experience, and preliminary results with the use of internal distraction osteogenesis for maxillary hypoplasia at one teaching institution.

PATIENTS AND MATERIALS

Over a 5-year period, more than 300 patients with craniofacial and dentofacial defects have undergone oral and maxillofacial surgery at our center to correct their skeletal discrepancies. Of these, 10 have had maxillary distraction osteogenesis done with internal distractors. Follow-up of 6 months or more was available for 8 patients. Stereolithographic models were used to bend distractors prior to surgery in 6 patients.

RESULTS

Latency prior to the start of distraction was 3 to 7 days and varied with the age of the patient. Distraction occurred at approximately 1 mm per day with an average distraction length of 8.5 mm (range, 6-10 mm). Excellent occlusal results were obtained in 5 patients. Major complications including nonunion and failure to achieve acceptable occlusal results were observed in 3 patients. Minor complications including pain and loosening of the distracter devices were observed in 2 patients, but did not appear to affect the esthetic and functional results.

CONCLUSIONS

Distraction osteogenesis is a useful alternative to traditional orthognathic surgery to treat maxillary hypoplasia. Internal distractions are attractive to patients, but are more difficult to place and can cause discomfort to patients when trying to achieve an ideal primary vector of distraction. Stereolithographic models can help with placement of the device. Changes in design of distractors may help with patient discomfort.

Unilateral Mandibular Ramus Elongation by Intraoral Distraction Osteogenesis

Successful correction of facial asymmetry by mandibular distraction osteogenesis relies on mastering vector control. Lack of necessary vector control continues to compromise the treatment modality. The purpose of this study was to describe a new simplified method for vector transfer and to evaluate this method according to the outcome and the efficacy of distraction osteogenesis in the correction of unilateral mandibular hypoplasia and asymmetry. Twenty-seven patients with unilateral hypoplasia of the mandibular ramus underwent unilateral mandibular distraction osteogenesis with intraoral distraction devices. Posterior-anterior and lateral cephalograms were analyzed by digitalization. Changes in sagittal, vertical, and transversal linear and angular dimensions after the distraction treatment were evaluated by measurements performed on headfilms taken before and after surgery. Means and variances were calculated for selected cephalometric variables for each time point. The differences between the control and the treatment side were calculated, statistically described, and compared with a paired Student t test. Correction of the mandibular asymmetry, chin position, and the canting of the occlusal plane was obtained in all patients clinically, as well as radiographically, by the use of intraoral unidirectional distraction osteogenesis.

Skeletal volume enhancement: implants and osteotomies

PURPOSE OF REVIEW

Facial plastic surgeons are concerned with improving or restoring function and form. Most surgeons perform primarily soft tissue procedures, which alone are often sufficient. However, deficiencies in the underlying craniomaxillofacial skeleton must also be addressed. Facial skeletal augmentation remains an essential aspect of cosmetic and reconstructive surgery. This article reviews the basic alloplastic biomaterials available for facial volume enhancement, discusses the zygomatic sandwich osteotomy for malar augmentation, and describes recent applications of distraction osteogenesis in the craniomaxillofacial region. An update in tissue engineering and computer modeling is also provided.

RECENT FINDINGS

High-porosity expanded polytetrafluoroethylene has been developed to provide a softer feel with less shrinkage and migration because of better biointegration and cellular ingrowth. Long-term results with porous polyethylene have demonstrated superior biocompatibility and minimal complications. Hydroxyapatite cement has been associated with an immunoguided delayed inflammatory reaction that leads to thinning of the overlying skin and exposure of the implant.Applications of distraction osteogenesis are rapidly expanding and include deformities of the mandible, midface, and cranium. There has been a trend toward the use of internal hardware, and internal devices are being developed to deliver a greater degree of vector control. Biodegradable devices have been developed to eliminate the second surgical procedure necessary for hardware removal. In the future, successful tissue engineering could eliminate many of the drawbacks associated with implants and osteotomies. The ability to stimulate stem cells to generate autogenous bone has been demonstrated in the laboratory. A novel application of computer technology that integrates laser surface scanning and digitizing with computer-aided design and manufacturing to produce facial prostheses has been described.

SUMMARY

An abundance of alternatives exist for skeletal volume enhancement including alloplastic implants, standard osteotomies, and distraction osteogenesis. The surgeon must evaluate the pros and cons of each technique in the context of each individual patient to determine the most appropriate option. Technologic advances in biomaterials, distraction hardware, computer modeling, and tissue engineering will continue to supply the surgeon's repertoire with improved methods to augment and restore the craniomaxillofacial skeleton.