Distraction Osteogenesis Procedure Research Articles

Anatomic and functional masseter muscle adaptation following orthognathic surgery—MRI analysis in 3 years of follow-up

BackgroundOrthodontic and surgical technical advances in recent years have resulted in treatment opportunities for a whole range of craniofacial skeletal disorders either in the adolescent or adult patient. In the growing child, these can include myofunctional orthodontic appliance therapy or distraction osteogenesis procedures, while in the adult, the mainstay approach revolves around orthognathic surgery.The literature agrees that for a change in craniofacial morphology to remain stable, the muscles acting upon the facial skeleton must be capable of adaptation in their structure and, therefore, their function. Failure of the muscles to adapt to the change in their length or orientation will place undesirable forces on the muscle attachments leading to potential instability of the skeleton. Adaptation can occur through various processes including those within the neuromuscular feedback mechanism, through changes within muscle structure or through altered muscle physiology, and through changes at the muscle/bone interface.It is now accepted that because there is no single method of assessing masticatory function, several measures should be taken, and whenever possible, simultaneously.MethodsThis investigation was designed to apply several, newly developed and more sophisticated methods of measuring muscle structure and function to a situation where adaptation of muscle is pivotal to the success of a therapeutic approach. Patients attending the combined orthodontic/orthognathic surgery clinic at the Clitrofa – Centro Médico, Dentário e Cirúrgico, in Trofa, Portugal, were screened. Ten patients scheduled for a bimaxillary osteotomy involving a combination of maxillary Le Fort I impaction procedure coupled with a sagittal split advancement of the mandible were selected to form the study group.The patients have MRI of the masseter muscle to evaluate the masseter muscle volume and fibre orientation changes. This exam was taken before surgery (T0), 6 to 12 months after surgery (T1), and 3 years after surgery (T2), by two independent observers, according to the protocol jointly developed between the Eastman Dental Institute – University of London and the MRI Centre - Department of Radiology at John Radcliffe Hospital – University of Oxford.ResultsSignificant differences (p < 0.05) have been identified between Time 0 (pre-op) and Time 1 (6–12 months post-op) regarding the masseter area (mm2). The differences against Time 0 (pre-op) seem to disappear at Time 2 (3 years post-op).ConclusionsMRI therefore seems to be a valid tool for measuring differences in the masseter muscle area and volume associated with high-severity occlusal deformities, although showing not to be as efficient in detecting the same differences in cases of low-severity occlusal deformities.

Impact of Anterior and Posterior Vault Distraction Osteogenesis (A-PVDO) and 3D-Printed Positioning/Shaping Templates in Apert Syndrome: A Case Series Study.

This study seeks to examine the impact of anterior and posterior vault distraction osteogenesis (A-PVDO) in conjunction with 3D-printed positioning and shaping templates for the management of Apert syndrome. From January 2018 to February 2022, a retrospective analysis was conducted on 6 cases of Apert syndrome employing fronto-orbital 3D-printed positioning and molding templates. The cranium underwent surgical modification in accordance with the template's configuration and was affixed with absorbable plates. Subsequently, distraction devices were applied, encompassing both anterior and posterior craniotomies. The evaluation encompassed clinical outcomes, complications (including cerebrospinal fluid leakage and infection), safety, and the feasibility of the distraction osteogenesis procedure. Six patients diagnosed with Apert syndrome underwent treatment involving the integration of fronto-orbital 3D-printed positioning and shaping templates in conjunction with anterior and posterior cranial distraction osteoplasty. Follow-up durations ranged from 18 to 32 months (average: 22mo). No instances of fronto-orbital retraction, cerebrospinal fluid leakage, or intracranial infection were noted during the follow-up period. The sole reported complication entailed an infection at the extension rod site in 1 case. All patients conveyed satisfaction with the treatment outcomes. The application of 3D-printed positioning and shaping templates in tandem with anterior and posterior cranial distraction osteogenesis demonstrates efficacy in addressing Apert syndrome. Notably, significant enhancements in head shape and orbit were observed, and the incidence of postoperative complications such as cerebrospinal fluid leakage and infection remained minimal. Moreover, long-term follow-up affirmed stability.

Multidirectional Cranial Distraction Osteogenesis for Craniosynostosis

In this article we explain in detail the Multidirectional Cranial Distraction Osteogenesis(MCDO)procedure for treating craniosynostosis, in which the multiple cranial bone flaps are pulled up in different directions by the external distractor with the helmet-type frame. MCDO has several advantages over conventional procedures such as unilateral cranial distraction osteogenesis(UCDO). First, the design of the osteotomy in MCDO is flexible depending on the deformities. Each bone flap can be moved to the desired direction in MCDO, while being moved only in one direction along the axis of the distractor in UCDO. This enables remodeling of the deformed cranium to the desired shape. Second, compared with UCDO, the distance between each bone flap after distraction is narrower in MCDO, allowing earlier bone formation and fusion, and thus a shorter consolidation period. Third, the expansion efficacy of MCDO is greater than that of UCDO. The maximum defects of MCDO were the large amount of osteotomy and the resulting heavy bleeding. Therefore, we have recently attempted to improve the design and procedure of osteotomy. The MCDO method allows all phenotypes of skull deformity to be reshaped by distraction osteogenesis.

Posterior cranial vault distraction osteogenesis: A systematic review.

Posterior cranial vault distraction osteogenesis (PCVDO) has become the treatment of choice in specific indications within 12 years since its introduction in 2009. It is used to treat or prevent Intracranial hypertension secondary to craniosynostosis. However, there is still a lack of evidence describing this procedure's safety concerning the osteotomy line being close to the torcula. This systematic review aims to generate evidence regarding the safety of this new technique. A systematic search of Pubmed and Embase database were done without any time limit until the last search date of July 31, 2021. Articles focused on posterior cranial vault distraction osteogenesis were shortlisted using defined inclusion criteria. In addition, complications, volume gain, and distraction protocols in patients with craniosynostosis were assessed. The review included 11 articles from 11 different centres. Of the Total 241 patients, 51 were non-syndromic patients, and 190 were syndromic patients. There were 242 procedures done on 241 patients. The proportion of patients with complications was 30%. Wound infection was the most commonly reported complication. PCVDO resulted in 20-25% volume gain and successfully prevented increased intracranial pressure (ICP). The systematic review has significantly identified a 30.606% incidence of complications in PCVDO. No mortality was linked directly to the Posterior cranial vault distraction osteogenesis procedure (PCVDO). The authors identified the evolution of many unique vectors and osteotomy designs customized for patients and practices for safe surgery. The effects of PCVDO on the anterior cranial fossa remain a topic of interest and require observational studies for better understanding.

Acute-shortening and re-lengthening (ASRL) procedure with monorail fixator to treat femur/tibia nonunion: A retrospective study

BackgroundThe distraction osteogenesis procedure has a high potential to treat bone defect problems. The alternative technique to treat nonunion associated with a bone defect is the acute shortening and re-lengthening (ASRL) procedure. This study aimed to evaluate the outcome of ASRL procedure with a monorail fixator to treat femur/tibia nonunion associated with the bone defect. MethodRetrospective analysis was performed to patients who received ASRL procedure with monorail fixator for femur or tibia nonunion from October 2018 to October 2020 at Prof. Dr. R. Soeharso Orthopaedic hospital. One case was loss to follow-up and excluded from the study. The rest of 16 cases were included for further analysis. The evaluation was performed to the demographic, intraoperative procedure, problems/complications, additional procedure, and final outcome. ResultsThere were 13 male and three female patients with age ranged from 16 to 64 years old. The follow-up period ranges 9–31 months. ASRL procedures performed to 6 femur and 10 tibias. The problems/complications: two cases with problems associated with callus formation, two cases of fracture at corticotomy site, one case of skin necrosis, one case of osteomyelitis, one case of malrotation. Additional surgical procedures were needed 5/16 (31.2%) cases. Evaluation at the final follow-up period showed 14/16 (87.5%) cases had a complete bone union. ConclusionsAcute shortening and re-lengthening (ASRL) could be reliable as a method of treatment for femur/tibia nonunion associated with the bone defect. Several possible complications need to be considered prior to perform this procedure.

Syndrome-related outcomes following posterior vault distraction osteogenesis.

The most commonly occurring syndromic craniosynostoses are Apert syndrome, Crouzon syndrome, Pfeiffer syndrome, and Saethre-Chotzen syndrome. There is insufficient data regarding postoperative syndrome-related outcomes following the posterior vault distraction osteogenesis (PVDO) procedure, as well as data addressing whether or not additional procedures will be subsequently necessary to comprehensively treat children who undergo PVDO. Thus, the objective of this study is to describe and compare syndrome-related potential complications and outcomes associated with the PVDO procedure. An observational retrospective study was performed on consecutive patients (n=24) with Apert syndrome, Crouzon syndrome, Pfeiffer syndrome, or Saethre-Chotzen syndrome, respectively, who underwent PVDO between 2012 and 2019. Demographic data (patient gender and age when the PVDO procedure was performed), diagnosis, surgery-related data, and outcome data (perioperative and midterm complications and need for additional surgery) were verified. Total relative blood transfusion volumes per kilogram for the patients were as follows: 22.75 ± 9.30 ml for Apert syndrome, 10.73 ± 2.28 ml for Crouzon syndrome (Apert versus Crouzon, p<0.05), 18.53 ± 8.08 ml for Pfeiffer syndrome, and 19.74 ± 9.12 ml for Saethre-Chotzen syndrome. None of the patients required a secondary procedure to alleviate intracranial pressure except for a Saethre-Chotzen patient. PVDO is an effective technique to address elevated intracranial pressure in SC patients that alleviates the need for secondary procedures at midterm follow-up. Apert syndrome patients presented relatively higher total blood transfusion rates than Crouzon syndrome patients who were operated on at a later age and weighed more.

Morphological improvement after multi-directional cranial distraction osteogenesis procedure for syndromic craniosynostosis.

The multidirectional cranial distraction osteogenesis (MCDO) procedure, which uses an external distraction device, enables tailor-made distraction in an arbitrary direction, eliminating the disadvantage of unidirectional distraction with an internal distraction device. Multiple-suture synostosis cases for syndromic craniosynostosis patients are better indicated for this procedure. Here the authors describe seven cases in which the MCDO procedure was used to treat syndromic craniosynostosis. In each case, the MCDO procedure and postoperative distraction, with reference to midsagittal vector analysis of normal morphology in Japanese children, resulted in morphological improvement.The video can be found here: https://vimeo.com/519006555

Anatomical Concepts of Distraction Osteogenesis: An Orthopaedic Case in Western Kenya

Various pathologies that lead to bone gaps of are difficult to manage and each presentation may require an individualized protocol of management. In the present case, the compound wedge fracture was initially sub-optimally managed leading to more complications, non-union, large collection of sequestrum and sepsis. This unique case required a complex management and salvage of the limb without damaging vital relations such as the nerves, muscles and blood vessels. After thorough assessment, a distraction osteogenesis procedure was recommended to restore the limb functions.

Interest and outcomes of alveolar distraction osteogenesis for dental implant rehabilitation following mandibular reconstruction

Introduction: Alveolar distraction osteogenesis (ADO) is one of vertical bone augmentation technique used to restore the vertical bone discrepancy between the transplanted graft and the residual alveolar bone after mandibular reconstruction. The aim of this article is to present the clinical outcomes of ADO applied to reconstructed mandible for three patients. Observation: Three patients underwent alveolar distraction osteogenesis procedure on mandibula reconstructed by fibula free flap (n = 2) or iliac crest free flap (n = 1). The mean bone height increase was 11 mm. 16 implants have been placed in all patients, with a success rate of 100% and a mean follow-up of 25 months. Two complications occurred without compromising the final outcome of the procedure: one fracture of the basal bone and one bony interference, both during activation phase. Commentaries: ADO can be performed on reconstructed mandible with free flap to restore alveolar height. An acceptable implant-to-crown ratio allows an optimal supported implant prosthesis. The particular antecedent of our patients can lead to uncommon complications such as basal bone fracture, but doesn't seem to compromise implant placement with good success rate. Conclusions: ADO performed on reconstructed mandible allows appropriate dental implant rehabilitation, achieving good esthetics and occlusal outcomes.

Craniofacial and Long Bone Development in the Context of Distraction Osteogenesis.

Bone retains regenerative potential into adulthood, and surgeons harness this plasticity during distraction osteogenesis. The underlying biology governing bone development, repair, and regeneration is divergent between the craniofacial and appendicular skeleton. Each type of bone formation is characterized by unique molecular signaling and cellular behavior. Recent discoveries have elucidated the cellular and genetic processes underlying skeletal development and regeneration, providing an opportunity to couple biological and clinical knowledge to improve patient care. A comprehensive literature review of basic and clinical literature regarding craniofacial and long bone development, regeneration, and distraction osteogenesis was performed. The current understanding in craniofacial and long bone development and regeneration is discussed, and clinical considerations for the respective distraction osteogenesis procedures are presented. Distraction osteogenesis is a powerful tool to regenerate bone and thus address a number of craniofacial and appendicular skeletal deficiencies. The molecular mechanisms underlying bone regeneration, however, remain elusive. Recent work has determined that embryologic morphogen gradients constitute important signals during regeneration. In addition, striking discoveries have illuminated the cellular processes underlying mandibular regeneration during distraction osteogenesis, showing that skeletal stem cells reactivate embryologic neural crest transcriptomic processes to carry out bone formation during regeneration. Furthermore, innovative adjuvant therapies to complement distraction osteogenesis use biological processes active in embryogenesis and regeneration. Additional research is needed to further characterize the underlying cellular mechanisms responsible for improved bone formation through adjuvant therapies and the role skeletal stem cells play during regeneration.

Rigid Video Laryngoscopy for Intubation in Severe Pierre Robin Sequence: A Retrospective Review.

The anatomy of children with severe Pierre Robin sequence can present a challenge for direct laryngoscopy and intubation. Advanced techniques including flexible fiberoptic laryngoscopic intubation have been described but require highly specialized skill and equipment. Rigid video laryngoscopy is more accessible but has not been described in this population. Retrospective cohort study. A retrospective review was completed at a tertiary care center of all children between January 2016 and March 2020 with Pierre Robin sequence who underwent a mandibular distraction osteogenesis procedure. Intubation events were collected, and a descriptive analysis was performed. A univariate logistic regression model was applied to direct laryngoscopy and flexible fiberoptic laryngoscopy with rigid video laryngoscopy as a reference. Twenty-five patients were identified with a total of 56 endotracheal events. All patients were successfully intubated. Direct laryngoscopy was successful at first intubation attempt in 47.3% (9/19) of events. Six direct laryngoscopy events required switching to another device. Rigid video laryngoscopy was successful at first intubation attempt in 80.5% (29/36) of events. Two cases required switching to another device. Flexible fiberoptic laryngoscopy was found successful at first intubation attempt in 88.9% (8/9) of events. Direct laryngoscopy was 4 times more likely to fail first intubation attempt when compared to rigid video laryngoscopy (P < .05). There was no significant difference between rigid video laryngoscopy and flexible fiberoptic laryngoscopy for intubation. For children with Pierre Robin sequence rigid video laryngoscopy should be considered as a first attempt intubation device both in the operating room and for emergent situations. 4 Laryngoscope, 131:1647-1651, 2021.

Temporomandibular Joint Dysplasia in Cranio-Maxillofacial Dysplasia: A Retrospective Study. Guideline Treatment Proposal.

Cranio-Maxillofacial Dysplasias (CMD), including Craniofacial Microsomias, syndromes (such as Treacher Collins or Williams) and isolated Condylo-Mandibulo-Dysplasia, is a controversial subject with treatments as diverse as diagnostic classifications. The authors present here a retrospective study of 85 patients, with congenital condyle dysplasia arising from these 3 main types of CMD, treated with different techniques that aimed to normalize the facial skeleton and occlusion. The authors studied retrospectively 85 patients, aged from 3 to 53 years old, affected by different types of CMD. Treatment options included: costochondral grafts, orthognathic surgeries, distraction osteogenesis procedures, orthodontic and dentofacial orthopedic treatments, and soft tissues surgeries. Outcomes were evaluated by the surgical team. Seventeen patients were treated with costochondral grafting, 14 with distraction osteogenesis, 17 with orthodontic and dentofacial orthopedic, and 45 with orthognathic surgery. The authors did not perform any nerve grafting or temporomandibular joints prosthesis placement. Fifty-one patients presented an excellent result, 10 a good result, 9 a poor result, 2 a bad result, and 14 an unknown result. Several different treatments of CMD can be proposed. The authors think that major defect in children should undergo costochondral grafting because of its growth potential while in case of minor defect, orthopedic treatment should be tried in the first place. Distraction osteogenesis should be reserved for cases with poor response after orthopedic treatment or growth insufficiency with costochondral grafting. Orthognathic surgery is often necessary at the end of the growth period to obtain an excellent result. Temporomandibular joints prosthesis should be reserved for extreme cases.

Effectiveness of a Piezoelectric-Assisted Distraction Osteogenesis Procedure for the Treatment of Ankylosed Permanent Front Teeth.

A common complication of tooth replantation after traumatic avulsion is tooth ankylosis causing dental malpositioning, partial loss of function, tipping of adjacent teeth and worsening of aesthetics. The aim of this study is to evaluate the effects of a repositioning procedure of such ankylosed permanent front teeth by a distraction osteogenesis procedure. Five patients (mean age 13.4 years), with an ankylosed permanent front tooth in the anterior area, were enrolled in the present study. After the pre-operatory orthodontic preparation, each selected site was treated with single-tooth dento-alveolar block osteotomy surgery performed with a piezoelectric surgery device with ultrasonic cuts on the buccal side. Subsequently, a custom distraction device, made by a resin splint and a sector expansion screw, was set in such a way it delivered a force with direction and sense towards the planned position of the tooth as well as the osteotomy's incision. After a latency period of 14 days, the distraction of the dento-alveolar block was started with a rate of distraction of 0.8 mm per day. The average shift obtained by the ankylosed teeth was 7.8 ± 0.75 mm (±SD), and the ankylosed tooth was regularly positioned into the occlusion in 20.4 ± 1.85 days (±SD), with a slight relapse (±0.5 mm) observed after 1 year. This study indicates that a therapeutic approach combining piezoelectric surgery and orthodontic therapy may be useful for the treatment of ankylosed permanent teeth in the frontal area with a long-term follow-up over 5 years.

Long-term Prognosis of Mandibular Distraction in 3 Cases of Hypoglossia-Hypodactyly Syndrome without Extremity Anomalies

Summary:Hypoglossia-hypodactyly, or aglossia-adactylia syndrome with or without limb anomalies, is an extremely rare congenital condition. It is characterized by a narrow, V-shaped mandibular dental arch with micrognathia, and is typically challenging to treat. We have previously reported 3 patients with hypoglossia-hypodactyly syndrome without limb anomalies who were treated with transverse distraction osteogenesis at the mandibular symphysis during childhood. In this report, we present the long-term prognoses of these 3 cases, until 18 years of age. Of the 3 total cases, sufficient and stable results in occlusion, speech, mastication, and facial appearance were obtained in 2 cases with subsequent orthodontic treatments. Similar results were not observed in the remaining case when continuous orthodontic treatments were not performed. Based on these results, we propose that the transverse distraction osteogenesis procedure at the mandibular symphysis during childhood could be a reliable method to correct the V-shaped mandibular arch of hypoglossia-hypodactyly syndrome, when subsequent orthodontic treatments are provided during the patient’s growing period.

Computer-assisted surgery in therapeutic strategy distraction osteogenesis of hemifacial microsomia: Accuracy and predictability

BackgroundDistraction osteogenesis can be used to treat hemifacial microsomia in patients of any age group. Application of three-dimensional (3D) technology in the surgical planning of distraction osteogenesis allows the placement of an intraoral distractor to define the cutting line and help predict the outcome of surgery. AimThis study compared the results of distraction osteogenesis performed, using computer-assisted surgery, on OMENS-plus-classified M2A, M2B, and M3 type patients. Comparisons were in terms of either accuracy or predictability. Methods40 patients were selected to participate in the 8-month study. Preoperative image data from 3D-CT scans of the 40 patients were translated into DICOM format 3D cephalometrics, run using the computer software MIMICS version 18, and based on eight reference anatomical landmark points, five lines of measurement, and the midline of the mandibular plane. The distraction vector for the affected side of mandible was selected and the elongation process simulated repeatedly until satisfactory results were obtained. The surgical guide was created using CAD/CAM-RP technology. The distraction osteogenesis procedure was then performed using the surgical guides. Follow-up for all patients continued until 8 months postoperatively. Accuracy with and without computer-assisted surgery was assessed linearly and volumetrically. Simple mean comparisons and paired t-tests were conducted using IBM SPSS V21. ResultsIn those patients who received computer-assisted surgery, distraction in the M2A type mandible showed accuracy of around 97.77% ± 7.92% (p > 0.05) for height and 97.91% ± 10.23% (p > 0.05) for length of the mandible. Meanwhile, the M2B type mandible presented accuracy of around 93.85% ± 8.07% (p > 0.05) for height and 95.85% ± 10.16% (p > 0.05) for length. For the M3 type mandible accuracy was around 98.42% ± 6.58% (p > 0.05) for height and 97.14% ± 11.45% (p > 0.05) for length. These measurements showed no significant differences between preoperative design and real outcome. ConclusionsIndividualized guides improve the accuracy of distraction osteogenesis. They help the surgeon to identify the mandibular defect and ensure the desired outcome after the operation.

Effect of "accordion" technique on bone consolidation during distraction osteogenesis

To investigate the effect, right timing, and mechanism of "accordion" technique on bone regeneration in rat distraction osteogenesis model. Fifty-four 12-week-old male Sprague Dawley rats underwent right tibial distraction osteogenesis procedure. After a 5-day latency, the distraction was performed for 7 days followed by 6-week consolidation. All animals were randomly divided into 4 groups based on different periods of "accordion" maneuvers in consolidation phase: control group ( n=18) with no manipulation, and three experimental groups including early-phase group ( n=18), mid-phase group ( n=12), and late-phase group ( n=6) with "accordion" maneuvers applied at 1, 3, and 5 weeks, respectively. The duration of the "accordion" maneuver was 7 days consisting of a 3.5-day compression and 3.5-day distraction. Rats in control group and early-phase group were sacrificed at 2, 4, and 6 weeks of the consolidation phase; rats in mid-phase group were sacrificed at 4 and 6 weeks of the consolidation phase; and rats in late-phase group were sacrificed at 6 weeks of the consolidation phase. Bilateral tibias from 6 rats in each group at each time point were obtained. Callus formation was monitored by X-ray radiography every week; new bone was reconstructed by Micro-CT three-dimensional reconstruction. The change of bone structure was evaluated, and parameters containing bone volume (BV)/tissue volume (TV) ratio (BV/TV) and bone mineral density (BMD) in three thresholds (158-211, 211-1 000, 158-1 000) were recorded and calculated at 6 weeks. Mechanical test consisting of ultimate load, modulus of elasticity, and energy to failure was performed. Histological analysis, such as Von Kossa staining, Safranin O staining, and HE staining, was done. Immunohistochemical staining using markers of osterix (OSX), osteocalcin (OCN), and vascular endothelial growth factor (VEGF) was analyzed. Images of X-ray showed that callus formation increased significantly in the mid-phase group. Micro-CT three-dimensional reconstruction demonstrated the mid-phase group owned fastest reconstructed speed among 4 groups, the cortical bone was continual at 6 weeks. At 6 weeks, the BMD and BV/TV in thresholds 158-1 000 and 211-1 000 in mid-phase group were higher than those in other groups. The results of mechanical test showed that ultimate load, modulus of elasticity, and energy to failure in mid-phase group were significantly higher than those in other groups ( P<0.05). Histological testing showed that the continuity of bone marrow cavity in mid-phase group was evident at 6 weeks after distraction. Immunohistochemical analyses confirmed the expression levels of osteogenesis (OCN, OSX) and angiogenesis (VEGF) elevated remarkably and then returned to normal in mid-phase group. The "accordion" technique is beneficial for new callus formation in distraction area. Applying the maneuver during the middle phase of the consolidation period was effective to accelerate new bone formation in rat distraction osteogenesis model.

Can combined maxillomandibular distraction osteogenesis avoid bilateral sagittal split osteotomies?

Background: Maxillary expansion and transversal maxillary distraction osteogenesis are becoming increasingly popular approaches in orthognathic surgery. Intraoral transversal mandibular distraction (TMD) osteogenesis procedures are utilised in many cases of transverse mandibular deficiency with dental crowding of the mandibular anterior teeth in class I, II and III malocclusions. Dental and skeletal positional changes after TMD were studied prior to osteotomies on patients with diverse malocclusions. Le Fort I advancement, trans palatal distraction (TPD) and TMD were performed both together or in later cases separately starting with the TMD followed by TPD, Le Fort I about 4 weeks later. Methods: We sought to determine the facial aesthetic amelioration and the subsequent degree of mandibular advancement resulting in an adequate realignment of the dental arch. We also note that these changes result in a change in the facial mask both anteroposteriorly and transversally. Findings: The facial aesthetic modifications after TMD were evaluated with cephalometric analysis, computed tomography scan, three-dimensional analysis and photographic data in 50 patients. Conclusions: The combination of TMD with or without repositioning of the maxilla (Le Fort I) and TMD allows a relatively good restoration of the facial structure and harmony. In most cases we were able to avoid a bilateral sagittal split osteotomy due to significant mandibular lengthening.

Correction of Sagittal Craniosynostosis Using Distraction Osteogenesis Based on Strategic Categorization.

Distraction osteogenesis has been used to correct sagittal craniosynostosis in various ways. The purpose of this study was to introduce three distraction osteogenesis procedures by describing four objective measurements. Fifty-four patients with sagittal synostosis were recruited and assigned to one of three therapeutic groups: group 1, anteroposterior compression with bitemporal expansion (n = 35); group 2, bitemporal expansion (n = 9); and group 3, anteroposterior expansion with bitemporal expansion (n = 10). Distraction procedures were performed while maintaining dural attachment. Four indices-namely cranial index, head circumference, intracranial volume, and neurodevelopmental index (using the Bayley Scales of Infant Development II), were analyzed. The preoperative cranial index of group 1 (68.51 ± 4.73) differed significantly from those of groups 2 (76.75 ± 2.4; p < 0.05) and 3 (86.8 ± 3.99; p < 0.05). Postoperative cranial index in all groups converged to the mesocephalic cranial index. Preoperative intracranial volume determinations were within the normal range for the majority of participants in groups 1 and 2; however, most fell below -1 SD in group 3 [n = 8 (80 percent)]. Postoperatively, 90 percent of group 3 participants had intracranial volume values within the normal range. The preoperative mental and psychomotor developmental indices of group 3 were significantly lower than those in the other two groups. The postoperative analysis showed significant improvement in these indices in groups 1 and 3 or when all patients were analyzed. Symmetric sagittal synostosis can be effectively treated with distraction osteogenesis reformation guided by strategic categorization. Therapeutic, IV.

Application of Le Fort Ⅲ osteotomy with minimal invasive approach in the treatment of midfacial hypoplasia

To describe a minimal invasive approach in the Le Fort Ⅲ osteotomy procedure. 33 cases with midfacial hypoplasia were treated by Le Fort Ⅲ osteotomy.Incisions were performed with minimal invasive approach,through lower eyelid,intraoral and upper eyelid crease or medial part of eyebrow instead of coronal incision.After the completion of osteotomy,distraction osteogenesis or orthognathic procedures were followed. The midfacial segments achieved enough advancement without obvious relapse.Bleeding and operative time were reduced compared with coronal approach.No obvious scar was left. The Le Fort Ⅲ osteotomy procedure could be successfully performed through minimal approach with steady results and minimal scars.

Accelerated Bone Formation in Distracted Alveolar Bone After Injection of Recombinant Human Bone Morphogenetic Protein-2.

This study evaluates the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) on the quality and quantity of regenerated bone when injected into distracted alveolar bone. Sixteen adult beagle dogs were assigned to either the control or rhBMP-2 group. After distraction was completed, an rhBMP-2 dose of 330 μg in 0.33 mL was injected slowly into the distracted alveolar crest of the mesial, middle, and distal parts of the alveolar bone in the experimental group. Histologic and microcomputed tomography analyses of regenerated bone were done after 2 and 6 weeks of consolidation. After 6 weeks of consolidation, the vertical defect height in the middle of the regenerated bone was significantly lower in the rhBMP-2 group (2.2 mm) than in the control group (3.4 mm) (P <0.05). Additionally, the width of the regenerated bone was significantly greater in the rhBMP-2 group (4.3 mm) than in the control group (2.8 mm) (P <0.05). The bone density and volume of regenerated bone in the rhBMP-2 group were greater than in the control group after 6 weeks of consolidation (P <0.001). Injection of rhBMP-2 into regenerated bone after a distraction osteogenesis procedure significantly increased bone volume in the dentoalveolar distraction site and improved both the width and height of the alveolar ridge and increased the bone density.