Distraction osteogenesis of the craniofacial skeleton

Long-term follow-up of corrective jaw surgery including distraction osteogenesis in 32 patients with juvenile idiopathic arthritis

Dentofacial deformity following juvenile idiopathic arthritis (JIA) with temporomandibular joint (TMJ) involvement is associated with functional, aesthetic, and psychosocial impairment. Corrective surgical treatment includes combinations of orthognathic surgeries (OS). The aims of this study were to assess orofacial symptoms, functional and aesthetic status, and stability after OS including mandibular distraction osteogenesis (MDO). A prospective study was conducted of 32 patients with JIA of the TMJ and dentofacial deformities who underwent MDO as the only surgery or in combination with bilateral sagittal split osteotomy, Le Fort I, and/or genioplastybetween 2003 and 2018. Data from clinical examinations and cephalograms performed pre- and postoperative and at long-term (mean 4 years) were analysed. Patients experienced unchanged orofacial symptoms (all P > 0.05), short-term TMJ functional impairment (all P < 0.001), and long-term morphological improvements in SNB angle (P < 0.001), anterior facial height (P < 0.001), mandibular length (P = 0.049), overjet (P < 0.001 and P = 0.005), and posterior facial symmetry (P = 0.046). MDO as the only surgery or with secondary adjunctive OS improved dentofacial morphology in terms of mandibular advancement, anterior facial height, posterior facial symmetry, and incisal relationships without long-term deterioration in TMJ function or orofacial symptoms.

Long-term results of fronto-orbital advancement and remodeling using distraction osteogenesis in craniosynostosis patients

In the initial report describing the fronto-orbital distraction technique, bone segments were advanced preserving their attachments with the dura. This approach does not allow for the remodeling of the frontal segment. However, in the technique described herein, the fronto-orbital segment is separated from dura, remodeled, and advanced as a bone graft using distractors. Twenty-seven craniosynostosis patients that underwent fronto-orbital advancement and remodeling using distraction osteogenesis were retrospectively reviewed. The mean age at the time of surgery was 19.03 ± 9.19 months; the mean follow-up was 86.04 ± 34.98 months. The mean distraction amount was over 19 mm. No significant difference was found between frontal and occipital bone density measurements at the cortex and medulla. The mean total defect area was 4.79 ± 4.43 cm2 and the mean number of bone defects was 4.8 ± 2.2. The cephalic index decreased from 98.56 ± 6.39 to 87.63 ± 4.54, and 59.3% of the patients reached the normal range in the late postoperative period. Fronto-orbital advancement and remodeling using distraction osteogenesis appears to be safe and effective. Distraction of the frontal bone as a graft does not lead to bone resorption, and new bone formation and improvements in head shape can be achieved.

Apert syndrome and obstructive sleep apnea: Timing for midface surgery

OBJECTIVE

This study aims to determine the optimal timing for midface surgery in patients with Apert syndrome and Obstructive Sleep Apnea (OSA).

METHODS

We reviewed relevant articles from Web of Science and PubMed and conducted a bibliometric analysis.

RESULTS

A review of 74 documents published between 1981 and 2023 revealed that determining the optimal timing for surgery in cases of airway obstruction necessitates consideration of various factors, including the location and severity of airway abnormalities, craniofacial development, potential impact of treatment on future growth, psychological considerations, and overall physiological conditions. Although midface advancement surgery performed around ages 6 to 7 typically yields symptom relief and favorable long-term outcomes, the ideal surgical timing young children with severe OSA remains a contentious issue.

CONCLUSION

While midface surgery is frequently advocated at ages 6 to 7, there is an urgent need for enhanced cooperation and high-quality research to deepen our understanding.

Bone Density of the Condyle of Children with Craniofacial Microsomia and its Correlation with Condylar Resorption After Mandible Distraction Osteogenesis

OBJECTIVE

To investigate condylar bone density (BD) in children with craniofacial microsomia (CFM) and identify factors that contribute to early stage condylar resorption (CR) after mandibular distraction osteogenesis (MDO).

DESIGN

Retrospective study.

SETTING

Craniofacial department of a plastic surgery hospital.

PATIENTS

Fifty-one children with CFM classified as Pruzansky IIa based on complete pre-(T0) and post-MDO (T1) computed tomography (CT) data.

INTERVENTION AND MAIN OUTCOME MEASUREMENTS

Mimic 21.0 (Materialise Inc., Belgium) was used to measure bilateral BD and condylar height (CH) and volume (CV) of affected side. Children were split into groups based on either affected side BD or the distraction length (DL,25 mm as cutoff) .Bilateral BD was compared using a paired t-test in each group. The CH and CV of affected side at T0 and T1 were compared. The relative values of the CH and CV (CH ratio) and the volume (CV ratio) of the affected side were compared across the groups.

RESULTS

The BD was lower on affected side than on unaffected side. Regarding BD, CH and CV decreased after MDO in group I, while the CH ratio and CV ratio of group I was lower than that of groups II and III. Regarding DL, the CV ratio was lower in Group L than Group S.

CONCLUSIONS

The condylar bone quality on affected side is compromised in type IIa CFM. A low BD in combination with a larger distraction distance may increase the risk of CR; therefore, MDO in patients with such characteristics should be postponed.

H Vessel Formation as a Marker for Enhanced Bone Healing in Irradiated Distraction Osteogenesis

In the setting of bone defects, the injured vasculature and loss of hemodynamic inflow leads to hematoma formation and low oxygen tension which stimulates vascular expansion through the HIf-1α pathway. Most importantly, this pathway upregulates sprouting of type H vessels (CD31hiEmcnhi vessels). H vessels engage in direct interaction with perivascular osteoprogenitor cells (OPCs), osteoblasts, and preosteoclasts of bone formation and remodeling. This angiogenic-osteogenic coupling leads to synchronous propagation of vascular and bony tissue for regenerative healing. A growing body of literature demonstrates that H vessels constitute a large portion of bone's innate capacity for osteogenic healing. We believe that CD31hiEmcnhi vessels play a role in bone healing during distraction osteogenesis (DO). DO is a procedure that utilizes traction forces to facilitate induction of endogenous bone formation and regeneration of surrounding soft tissues such as skin, muscle, tendon, and neurovascular structures. While the H vessel response to mechanical injury is adequate to facilitate healing in normal healthy tissue, it remains inadequate to overcome the devastation of radiation. We posit that the destruction of CD31hiEmcnhi vessels plays a role in precluding DO's effectiveness in irradiated bone defect healing. We aim, therefore, to recapitulate the normal pathway of bony healing by utilizing the regenerative capacity of H vessels. We hypothesize that using localized application of deferoxamine (DFO) will enhance the H vessel-mediated vasculogenic response to radiation damage and ultimately enable osteogenic healing during DO. This discovery could potentially be exploited by developing translational therapeutics to hopefully accelerate bone formation and shorten the DO consolidation period, thereby potentially expanding DO's utilization in irradiated bone healing. Sprague-Dawley rats were divided into three groups: DO, radiation with DO (xDO), and radiation with DO and DFO implantation (xDODFO). Experimental groups received 35 Gy of radiation. All groups underwent DO. The treatment group received injections into the osteotomy site, every other day, beginning on postoperative day (POD) 4 of DFO. Animals were sacrificed on POD 40. For immunohistochemical analysis, mandibles were dissected and fixed in 4% paraformaldehyde for 48 hours, decalcified in Cal-Ex II for 2 days, dehydrated through graded ethanol of increasing concentration, and then embedded in paraffin. Samples were cut into 7-μm thick longitudinally oriented sections including the metaphysis and diaphysis. CD31 and Emcn double immunofluorescent staining were performed to evaluate the extent of CD31hiEmcnhi vessel formation. Bone sections were then stained with conjugated antibodies overnight at 4°C. Nuclei were stained with Hoechst. Slides were also double stained with Osterix and CD31 to study the quantity of H vessel-mediated recruitment of OPCs to accelerate bone healing. Images were acquired with a Nikon Ti2 widefield microscope and analyzed in NIS- Elements Advanced Research 5.41.02 software. The abundance of type H vessels is represented by the area fraction of CD31 + Emcn+ vessel area inside the regenerate sample. OPC concomitant proliferation into the distraction gap is represented by the area fraction of Osterix+ cell area inside of the regenerate sample. There were 6× more type H vessels in DO groups than in xDO groups. Localized DFO significantly increased the abundance of type H vessels of irradiated DO animals compared to xDO by 15× ( p  = 0.00133531). Moreover, the DO and xDODFO groups with higher abundance of type H vessels also demonstrated better angiogenesis and osteogenesis outcomes. Interestingly, xDODFO groups doubled the quantity of H vessel formation compared to DO, indicating a supraphysiologic response ( p  = 0.044655055). Furthermore, H vessel-mediated recruitment of OPCs mimicked the described H vessel formation trend in our study groups. Irradiated DO groups contained 3× less OPCs compared to DO controls. DFO treatment to xDO animals remediated irradiation damage by containing 12× Osterix+ cells. Finally, DFO treatment of irradiated animals quadrupled osteoprogenitor recruitment into the distraction gap compared to DO controls. In this study, we developed a novel approach to visualize CD31hiEmcnhi in paraffin sections to study DO regeneration. Normal DO demonstrated a significant upregulation of H vessel formation and associated angiogenic-osteogenic coupling. Radiation severely decreased H vessel formation along with an associated significant diminution of new bone formation and nonunion. DFO administration, however, resulted in vascular replenishment and the restoration of high quantities of CD31hiEmcnhi and OPCs, recapitulating the normal process of bony regeneration and repair. DFO treatment remediated new bone formation and bony union in irradiated fields associated with increased H vessel angiogenic-osteogenic coupling. While further studies are required to optimize this approach, the results of this study are incredibly promising for the long-awaited translation of localized DFO into the clinical arena.

Hemi one-piece distraction osteogenesis for unilateral coronal craniosynostosis

INTRODUCTION

It was the aim of the study to assess the efficacy of the hemi one-piece distraction osteogenesis and to compare it to the traditional one-piece distraction osteogenesis technique.

METHODS

Two different surgical techniques were used; the one-piece distraction and the hemi one-piece distraction. The principal distinction between the two techniques is that in the hemi style approach, the intact sutures on the contralateral side were left undisturbed, with no osteotomy performed.

RESULTS

The hemi one-piece group had a significantly lower median value of plastic surgery time, total operation time, and transfusion rate (plastic surgery time 69 min (range 65-120) vs. 20 min (range 17-32.5), p < 0.001; transfusion 80 mL (range 0-150) vs. 0 mL (0-60), p = 0.1. Nasofrontal advancement was successful with no major complications. Median endocranial angulation improved (one-piece: 166.1°-176.0°, hemi: 162.9°-173.0°, p = 0.023 & p = 0.012 respectively).

CONCLUSION

This study reveals less invasive, highly effective techniques for craniosynostosis treatment, notably a unilateral osteotomy with distraction method. Nevertheless, to confirm their long-term efficacy and durability, more studies with longer follow-ups are essential.

Lefort I Osteotomy With and Without Osteogenic Distraction in Cleft Lip and Palate Patients: Experience at Hospital Universitario Infantil De San José

INTRODUCTION

Cleft lip and cleft palate (CLP) are congenital diseases that lead to several secondary craniofacial anomalies, such as hypoplasia of the middle third of the face, which can be treated with different surgical techniques to help improve functional and esthetic alterations associated with the maxilla. This article reports the results of patients managed with LeFort I osteotomy in the same craniofacial surgery center for 10 years.

OBJECTIVE

To determine the postoperative results regarding recurrence rates, malocclusion, and speech status after surgical treatment, in patients with retrusion of the midface with CLP, who underwent LeFort I osteotomy with or without osteogenic distraction (OD).

METHODS

A descriptive cohort study was performed at the Hospital Infantil Universitario de San José in Bogotá, Colombia, between 2010 and 2020, evaluating 38 patients with CLP who met the inclusion criteria, all managed by LeFort I osteotomy with and without OD. The authors reported the sociodemographic information, as well as data related to speech before and after surgery, recurrence, complications, and cephalometric characteristics. The recurrence of the patients was described at 6 and 12 months after the surgical procedure.

RESULTS

A total of 43 patients met the inclusion criteria, of which 20 patients were managed with conventional LeFort I osteotomy, and 23 with LeFort I osteotomy with OD; 5 patients were excluded due to lack of data in the medical records, with a final sample of 38 patients. The distribution based on sex was: 57.8% men and 42.1% women. Regarding laterality, we have 7 patients with right CLP (18.42%), 11 patients with left CLP (28.9%), and 20 patients with bilateral CLP (52.63%), 100% of patients with a class III bite in Angle's classification. In group 1 (OD), 55% of the patients did not present changes in speech before surgery, 30% presented improvement in speech, and 15% worsened it. In group 2 (conventional advancement), 66% of the patients did not present changes in speech, 5.5% presented improvement, and 27.7% presented worsening of speech based on the preoperative condition, with a clinical recurrence at 6 months of 15% for group 1 and of 33% for group 2, and at 1 year of 20% for group 1 and 16% for group 2.

CONCLUSIONS

Osteogenic distraction is a safe method that can be applied in patients with CLP depending on the clinical characteristics. According to what is described in the literature, those patients who require advancement of up to 6 mm treated without OD have obtained good results, showing esthetic improvement by increasing the projection of the middle third of the face, without worsening of velopharyngeal insufficiency and achieving an adequate occlusal class (Angle I) in the immediate postoperative period or after the postoperative orthodontic management. However, in patients who require advances ≥7 mm, it is clear that OD is the best option, given its association with a lower recurrence rate, minimal changes in the speech, achieving occlusion edge-to-edge at the end of the distraction or Angle's class I, which is corroborated by the results obtained in this study.

Craniofacial Distraction Osteogenesis

Distraction osteogenesis (DO) of the craniofacial skeleton has become an effective technique for the treatment of both nonsyndromic and syndromic conditions. The advent of craniofacial DO has allowed for earlier intervention in pediatric patients with less complication risk and morbidity compared to traditional techniques. In this review, we will discuss current application and technique for craniofacial DO by anatomical region and explore future applications in craniofacial surgery.

Cranial Neural Crest Cells Contribution to Craniofacial Bone Development and Regeneration

PURPOSE OF REVIEW

This review aims to summarize (i) the latest evidence on cranial neural crest cells (CNCC) contribution to craniofacial development and ossification; (ii) the recent discoveries on the mechanisms responsible for their plasticity; and (iii) the newest procedures to ameliorate maxillofacial tissue repair.

RECENT FINDINGS

CNCC display a remarkable differentiation potential that exceeds the capacity of their germ layer of origin. The mechanisms by which they expand their plasticity was recently described. Their ability to participate to craniofacial bone development and regeneration open new perspectives for treatments of traumatic craniofacial injuries or congenital syndromes. These conditions can be life-threatening, require invasive maxillofacial surgery and can leave deep sequels on our health or quality of life. With accumulating evidence showing how CNCC-derived stem cells potential can ameliorate craniofacial reconstruction and tissue repair, we believe a deeper understanding of the mechanisms regulating CNCC plasticity is essential to ameliorate endogenous regeneration and improve tissue repair therapies.

Transfacial Two-pin External Mandibular Distraction Osteogenesis: A Technique for Neonatal Airway Obstruction from Robin Sequence

Surgical management in those with moderate-to-severe airway obstruction includes tongue-lip adhesion, tracheostomy, and/or mandibular distraction osteogenesis. This article describes a transfacial two-pin external device technique for mandibular distraction osteogenesis, utilizing minimal dissection.

Methods

The first percutaneous pin is transcutaneously placed just inferior to the sigmoid notch parallel to the interpupillary line. The pin is then advanced through the pterygoid musculature at the base of the pterygoid plates, toward the contralateral ramus, and exits the skin. A second parallel pin is placed spanning the bilateral mandibular parasymphysis distal to the region of the future canine. With the pins in place, bilateral high ramus transverse corticotomies are performed. Using univector distractor devices, the length of activation varies, with the goal of overdistraction to achieve a class III relationship of the alveolar ridges. Consolidation is limited to a 1:1 period with the activation phase, and removal is performed by cutting and pulling the pins out of the face.

Results

To guide optimal transcutaneous pin placement, transfacial pins were then placed through twenty segmented mandibles. Mean upper pin (UP) distance was 20.7 ± 1.1 mm from the tragus. The distance between the cutaneous entry of the UP and lower pin was 23.5 ± 0.9 mm, and the tragion-UP-lower pin angle was 118.7 ± 2.9°.

Conclusions

The two-pin technique has potential advantages regarding nerve injury and mandibular growth, given an intraoral approach with limited dissection. It may safely be performed on neonates whose small size may preclude the use of internal distractor devices.

A Proposal for the Classification of Temporomandibular Joint Disc Deformity in Hemifacial Microsomia

Hemifacial microsomia (HFM) is the second most common congenital craniofacial disease and has a wide spectrum of symptoms. The classic diagnostic criterion for hemifacial microsomia is the OMENS system, which was later refined to the OMENS+ system to include more anomalies. We analyzed the data of 103 HFM patients with magnetic resonance imaging (MRI) for temporomandibular joint (TMJ) discs. The TMJ disc classification was defined into four types: D0 for normal disc size and shape; D1 for disc malformation with adequate length to cover the (reconstructed) condyle; D2 for disc malformation with inadequate length to cover the (reconstructed) condyle; and D3 for no obvious presence of a disc. Additionally, this disc classification was positively correlated with the mandible classification (correlation coefficient: 0.614, p < 0.01), ear classification (correlation coefficient: 0.242, p < 0.05), soft tissue classification (correlation coefficient: 0.291, p < 0.01), and facial cleft classification (correlation coefficient: 0.320, p < 0.01). In this study, an OMENS+D diagnostic criterion is proposed, confirming the conjecture that the development of the mandibular ramus, ear, soft tissue, and TMJ disc, as homologous and adjacent tissues, is affected to a similar degree in HFM patients.

A bibliometric analysis of research on craniomaxillofacial distraction osteogenesis from 2000 to 2021

Objective

This study collected and summarized publications related to craniomaxillofacial distraction osteogenesis(DO) from 2000 to 2021, investigated trends in related research, and compared publications from different countries, institutions and journals. The aim is showcasing hotspots and frontiers in the field and providing a reference for future research.

Background

Craniomaxillofacial DO serves to treat different types of craniomaxillofacial dysplasia and bone defects and deformities. DO can significantly reduce surgical trauma, complications, and recurrence rate compared to conventional surgery. However, there is a lack of bibliometric analyses regarding Craniomaxillofacial DO.

Methods

CiteSpace and VOSviewer were used to analyze and visualize 3,141 articles and reviews searching through the Web of Science Core Collection(WOSCC) to obtain publications on craniomaxillofacial DO from 1 January 2000 to 31 December 2021.

Results

In the last 21 years, there has been a significant increase in the number of publications. The United States, the People's Republic of China, and Italy produce the vast majority of publications. University of Milan and University of Bologna are the most influential in this field. McCarthy JG is the most influential author. Obstructive sleep apnea, TMJ ankylosis and cleft lip and palate are potential research direction in this field.

Conclusion

Future research should focus on the precise indications and optimal timing of craniomaxillofacial DO and the evaluation of the long-term outcomes of various modified procedures. This study provides a relatively objective reference for related researchers, medical practitioners, and global health systems.

A Novel Alveolar Distractor Incorporating Nickel-Titanium Alloy Springs: A Preliminary In Vitro Study

A new design of an alveolar distractor using nickel−titanium (NiTi) open-coil springs was developed and investigated to produce distraction forces against the tensile forces of porcine attached gingiva to simulate human gingiva. We subjected 15 mm long NiTi open-coil springs (Highland and ORMCO) with three levels of forces (light, medium and heavy) to mechanical testing in a 37 ± 1 °C water bath. Ten strips of porcine mandibular attached gingiva were subjected to tensile tests to determine the resistance force. The forces from the springs were compared with the tensile forces from the porcine attached gingiva. Data between groups were analyzed with independent-samples T-tests (p-value < 0.05). The tensile strength and the Young modulus were greater in buccal compared to lingual porcine attached gingiva. Compared to other spring dimensions and companies, forces generated from 0.014 × 0.036″ ORMCO springs were the highest and could overcome the tensile resistance from porcine attached gingiva over the longest distraction range of 1.6 mm. This preliminary in vitro study introduced a new design of an alveolar distractor incorporated with NiTi open-coil springs that could generate light and continuous forces to overcome the resistance from porcine attached gingiva.

Endoscope-Assisted Fronto-Orbital Distraction Osteogenesis

SUMMARY

Anterior cranial vault fronto-orbital distraction osteogenesis is a promising treatment modality for children with unicoronal craniosynostosis. A minimally invasive, endoscope-assisted approach offers the additional potential benefits of less scalp scarring, decreased blood loss, and decreased scalp dissection. In this article, the authors present a novel technique for minimally invasive, endoscope-assisted fronto-orbital distraction osteogenesis.

Combining High-Resolution Hard X-ray Tomography and Histology for Stem Cell-Mediated Distraction Osteogenesis

Distraction osteogenesis is a clinically established technique for lengthening, molding and shaping bone by new bone formation. The experimental evaluation of this expensive and time-consuming treatment is of high impact for better understanding of tissue engineering but mainly relies on a limited number of histological slices. These tissue slices contain two-dimensional information comprising only about one percent of the volume of interest. In order to analyze the soft and hard tissues of the entire jaw of a single rat in a multimodal assessment, we combined micro computed tomography (µCT) with histology. The µCT data acquired before and after decalcification were registered to determine the impact of decalcification on local tissue shrinkage. Identification of the location of the H&E-stained specimen within the synchrotron radiation-based µCT data collected after decalcification was achieved via non-rigid slice-to-volume registration. The resulting bi- and tri-variate histograms were divided into clusters related to anatomical features from bone and soft tissues, which allowed for a comparison of the approaches and resulted in the hypothesis that the combination of laboratory-based µCT before decalcification, synchrotron radiation-based µCT after decalcification and histology with hematoxylin-and-eosin staining could be used to discriminate between different types of collagen, key components of new bone formation.

Treatment of Unicoronal Craniosynostosis by Rotational Flap Technique Preserves Blood Supply to the Frontal Bone Flap

BACKGROUND

Surgical correction of unicoronal craniosynostosis (UCS) remains a challenging problem. Long-term results are often unsatisfactory secondary to recurrence of the original deformity, requiring secondary operations such as fat grafting or complete revision of the calvarial remodeling. Distraction osteogenesis (DO) has recently emerged as a new modality for treatment of UCS, with promising results and decreased rates of reoperation compared with open cranial vault remodeling. A theoretical benefit of DO is preservation of blood supply to the frontal bone following osteotomy, as the frontal bone can be retained in situ compared with the complete removal and reshaping of the frontal bone during traditional fronto-orbital advancement. Preservation of blood supply to the frontal bone may allow for more robust bony healing and preservation of long-term growth potential; however, the vascularity of the frontal bone flap in DO has not previously been demonstrated. Here, we demonstrate unequivocally that blood supply to the frontal bone is preserved after creation of a rotational bone flap in DO management of UCS.

METHODS

Frontal bone flap creation via osteotomy for DO treatment of UCS was performed via previously reported technique. Indocyanine green was injected intravenously, and bone perfusion was assessed with a fluorescence imaging system.

RESULTS

Four patients underwent three cranial remodeling and three distractor removal procedures. After frontal bone flap creation via osteotomy for DO, perfusion to the osteotomized portion of the frontal bone flap is preserved. Blood flow is seen crossing the midline of the frontal bone. After removal of the distractor, perfusion in the osteoid consolidate is also observed.

CONCLUSIONS

Preservation of blood supply has not been previously demonstrated empirically in the setting of DO treatment of UCS. We show for the first time that during frontal bone flap creation, blood flow to the osteotomized portion of the frontal bone flap is maintained. Robust blood flow to the osteoid consolidate is also demonstrated. These data support the use of DO in treatment of UCS, as preserved blood supply to the bone is more likely to support improved healing and long-term results.

Cranial Bone Transport Promotes Angiogenesis, Neurogenesis, and Modulates Meningeal Lymphatic Function in Middle Cerebral Artery Occlusion Rats

BACKGROUND

Ischemic stroke is a leading cause of death and disability worldwide. However, the time window for quickly dissolving clots and restoring cerebral blood flow, using tissue-type plasminogen activator treatment is rather limited, resulting in many patients experiencing long-term functional impairments if not death. This study aims to determine the roles of cranial bone transport (CBT), a novel, effective, and simple surgical technique, in the recovery of ischemic stroke using middle cerebral artery occlusion (MCAO) rat model.

METHODS

CBT was performed by slowly sliding a bone segment in skull with a special frame and a speed of 0.25 mm/12 hours for 10 days following MCAO. Morris water maze, rotarod test, and catwalk gait analysis were used to study the neurological behaviors, and infarct area and cerebral flow were evaluated during CBT process. Immunofluorescence staining of CD31 and Nestin/Sox2 (sex determining region Y box 2) was performed to study the angiogenesis and neurogenesis. OVA-A647 (ovalbumin-Alexa Fluor 647) was intracisterna magna injected to evaluate the meningeal lymphatic drainage function.

RESULTS

CBT treatment has significantly reduced the ischemic lesions areas and improved the neurological deficits in MCAO rats compared with the rats in the control groups. CBT treatment significantly promoted angiogenesis and neurogenesis in the brain of MCAO rats. The drainage function of meningeal lymphatic vessels in MCAO rats was significantly impaired compared with normal rats. Ablation of meningeal lymphatic drainage led to increased neuroinflammation and aggravated neurological deficits and ischemic injury in MCAO rats. CBT treatment significantly improved the meningeal lymphatic drainage function and alleviated T-cell infiltration in MCAO rats.

CONCLUSIONS

This study provided evidence for the possible mechanisms on how CBT attenuates ischemic stroke injury and facilitates rapid neuronal function recovery, suggesting that CBT may be an alternative treatment strategy for managing ischemic stroke.

Maxillary Changes Following Facial Bipartition - A Three-Dimensional Quantification

INTRODUCTION

Children with Apert syndrome have hypertelorism and midfacial hypoplasia, which can be treated with facial bipartition (FB), often aided by rigid external distraction. The technique involves a midline osteotomy that lateralizes the maxillary segments, resulting in posterior cross-bites and midline diastema. Varying degrees of spontaneous realignment of the dental arches occurs postoperatively. This study aims to quantify these movements and assess whether they occur as part of a wider skeletal relapse or as dental compensation.

METHODS

Patients who underwent FB and had high quality computed tomography scans at the preoperative stage, immediately postsurgery, and later postoperatively were reviewed. DICOM files were converted to three-dimensional bone meshes and anatomical point-to-point displacements were quantified using nonrigid iterative closest point registration. Displacements were visualized using arrow maps, thereby providing an overview of the movements of the facial skeleton and dentition.

RESULTS

Five patients with Apert syndrome were included. In all cases, the arrow maps demonstrated initial significant anterior movement of the frontofacial segment coupled with medial rotation of the orbits and transverse divergence of the maxillary arches. The bony position following initial surgery was shown to be largely stable, with primary dentoalveolar relapse correcting the dental alignment.

CONCLUSIONS

This study showed that spontaneous dental compensation occurs following FB without compromising the surgical result. It may be appropriate to delay active orthodontic for 6-months postoperatively until completion of this early compensatory phase.

Endoscopic-Assisted Fronto-Orbital Distraction Osteogenesis: Initial Patient Report

BACKGROUND

The purpose of this manuscript is to introduce a novel endoscopic-assisted approach for creation of osteotomies and distractor hardware placement for unicoronal craniosynostosis.

METHODS

Only three small incisions are performed, one at the anterior fontanelle, pterional region, and upper lateral blepharoplasty location. Unicoronal strip craniectomy and osteotomies in temporal bone, nasofrontal junction, lateral orbital rim, sphenoid wing, orbital roof, and contralateral frontal bone are performed through these incisions with the assistance of a 30° 5-mm endoscope. One linear cranial distractor is inserted through the pterional incision and fixated across the unicoronal suturectomy.

RESULTS

Endoscopic-assisted fronto-orbital distraction osteogenesis has been performed on 3 patients with unicoronal craniosynostosis. Median age at surgery was 5.4 months (95%CI 5.0-6.1). Median operative duration was 98 minutes (95%CI 91-112), and estimated blood loss was 25 mL (95%CI 15-150). Median length of distraction achieved was 25.7 mm (95%CI 21.9-28.0), based on lateral skull x-rays obtained on the last day of activation. Distractors were removed 2.3 months postoperatively (95%CI 2.1-3.1), and operative duration of distractor removal was 20 minutes (95%CI 19-29). There was 1 complication, a transient cerebrospinal fluid leak thought to have been caused by a pinpoint injury to the dura at the nasofrontal junction, which was managed expectantly and resolved spontaneously by the fourth postoperative day.

CONCLUSIONS

Endoscopic-assisted fronto-orbital distraction osteogenesis is a promising treatment modality for children with unicoronal craniosynostosis combining the benefits of distraction osteogenesis with a minimally invasive approach. Additional experience and follow-up are needed to determine its utility, safety, and longevity.

The Most Frequently Cited References in the Articles Published in the Journal of Craniofacial Surgery Between 1995 and 2020

ABSTRACT

The aim of this study is to examine the cited-references in the articles published in the Journal of Craniofacial Surgery between 1995 and 2020. On February 20, 2021, all articles published before January 1, 2021, in the Journal of Craniofacial Surgery were listed using advanced search in the Web of Science database. The journal's ISSN and e-ISSN numbers were used to perform this search. All information about these articles has been marked and exported to Tab-delimited (Win) format. It was then analyzed with the VOSviewer software. In the Web of Science database, it was investigated that a total of 11,888 articles were published in the Journal of Craniofacial Surgery between 1995 and 2020. A total of 137,829 different cited-references were used in these 11,888 articles. The top 15 most cited-references were identified. It was found that the first 3 most cited journals were Plastic and Reconstructive Surgery (n: 21,700; 15.74%), Journal of Craniofacial Surgery (n: 12,199; 8.85%), and Journal of Oral and Maxillofacial Surgery (n: 9383, 6.81%), respectively. As far as we know, the present study is the first study to analyze the cited-references in the field of craniofacial surgery. The authors think that the publications determined in this study are fundamental building blocks for both the field of craniofacial surgery and the Journal of Craniofacial Surgery.

A Single-Center Retrospective Review of Perioperative Complications and Reoperation Rates Between Open Cranial Vault Remodeling and Distraction Osteogenesis for Unilateral Coronal Craniosynostosis

BACKGROUND

Unilateral coronal craniosynostosis (UCS) is the third most prevalent form of craniosynostosis. Traditional treatment of UCS has been achieved with fronto-orbital advancement and cranial vault remodeling (FOAR), but utilization of cranial distraction osteogenesis (DO) techniques has increased. This study aims to compare perioperative complications and reoperation trends in FOAR versus DO techniques at a single institution.

METHODS

An Institutional Review Board-approved retrospective review was performed from January 1999 to November 2018 at a single institution. Patients were those that have undergone FOAR or DO with an anterior rotational flap technique as previously described. Indications for secondary procedures included: contour deformities, relapse, surgical site infection, and persistent cranial defects.

RESULTS

Eighty-one patients with UCS were identified, 64 patients underwent FOAR and 17 patients underwent DO. When perioperative characteristics were compared, patients who underwent DO were younger in age, however, there was no significant difference in transfusion requirement or length of stay between patient cohorts. Surgery time was increased in DO patients. When perioperative complications were compared, more intraoperative dural tears were observed in the FOAR cohort. When unplanned reoperation rates were compared, patients who had undergone FOAR had a statistically significant higher reoperation rates at 5 years of follow up. When including routine distractor removal as a reoperation, reoperative rate was increased in the DO cohort. No difference in reoperation rates was noted at 5 years following index operation.

CONCLUSIONS

The safety profile of DO is similar to that of traditional FOAR techniques for treatment of UCS. Longer-term follow-up studies are needed to elucidate whether outcomes are durable, but the unplanned reoperation rate in DO is less than that of FOAR at 5 years and presents several advantages that warrants its use in patients with UCS.

Distraction Osteogenesis in Craniofacial Surgery: Past, Present, and Future

ABSTRACT

Distraction osteogenesis (DO) is considered one of the treatments of choice for the surgical correction of malformations of the craniofacial skeleton. This is due to its ability to generate bone at the distraction site along with the accompanying soft tissue changes, the possibility to combine DO with traditional orthognathic procedures and the successful reported long-term outcomes following its application to various craniofacial deformities. The aim of this review is to present an overview of the literature on the evolution of DO applications in craniofacial surgery through the last 35 years.

Photobiomodulation combined with adipose-derived stem cells encapsulated in methacrylated gelatin hydrogels enhances in vivo bone regeneration

Reconstruction of bone defects is still a significant challenge. The aim of this study was to evaluate the effect of application of photobiomodulation (PBM) to enhance in vivo bone regeneration and osteogenic differentiation potential of adipose-derived stem cells (ADSCs) encapsulated in methacrylated gelatin (GEL-MA) hydrogels. Thirty-six Sprague-Dawley rats were randomly separated into 3 experimental groups (n = 12 each). The groups were control/blank defect (I), GEL-MA hydrogel (II), and ADSC-loaded GEL-MA (GEL-MA+ADSC) hydrogel (III). Biparietal critical sized bone defects (6 mm in size) are created in each animal. Half of the animals from each group (n = 6 each) were randomly selected for PBM application using polychromatic light in the near infrared region, 600-1200 nm. PBM was administered from 10 cm distance cranially in 48 h interval. The calvaria were harvested at the 20th week, and macroscopic, microtomographic, and histologic evaluation were performed for further analysis. Microtomographic evaluation demonstrated the highest result for mineralized matrix formation (MMF) in group III. PBM receiving samples of group III showed mean MMF of 79.93±3.41%, whereas the non-PBM receiving samples revealed mean MMF of 60.62±6.34 % (p=0.002). In terms of histologic evaluation of bone defect repair, the higher scores were obtained in the groups II and III when compared to the control group (2.0 for both PBM receiving and non-receiving specimens; p<0.001). ADSC-loaded microwave-induced GEL-MA hydrogels and periodic application of photobiomodulation with polychromatic light appear to have beneficial effect on bone regeneration and can stimulate ADSCs for osteogenic differentiation.

Efficacy and Versatility of Intraoral Monoplanar Distractors in the Correction of Extreme Mandibular Deformities and Severe Facial Asymmetries - A Retrospective Study

Introduction:

Distraction osteogenesis, has emerged as a revolutionary concept and an effective means to treat extensive craniomaxillofacial defects and malformations. In cases of mandibular distraction for patients with extreme acquired mandibular deformities, there is so far, no recorded literature on precise quantification and scientific estimation of the percentage of the efficacy of intraoral monoplanar distractors, for an objective evaluation of their effectiveness. The objective was to study the efficacy of intraoral mandibular monoplanar distractors in the correction of severe acquired mandibular deformities and gross facial asymmetries. To objectively evaluate their effectiveness by calculating the percentage of distraction achieved as against that aimed for, and to evaluate early and late complications encountered with their use.

Materials and Methods:

Five patients in the age group of 10–22 years, with extreme mandibular deformity and gross facial asymmetry secondary to longstanding temporomandibular joint (TMJ) ankylosis, were treated. Four patients had unilateral and one patient had bilateral TMJ ankylosis, with varying degrees of acquired mandibular hypoplasia, retrogenia, retrognathia, and asymmetry. They were managed by unilateral (3 patients) and bilateral (2 patients) mandibular distraction.

Results:

Maximum horizontal corpus and vertical Ramal distraction achieved was 19 mm and 17.6 mm, respectively. The percentage of the efficacy of the intraoral monoplanar distractors used in this study ranged from 65.38% to 109.09%. Severe mandibular deformities and facial asymmetries were successfully corrected in all five patients, with no major early or late complications encountered in any of them. Results achieved were stable with nil incidence of relapse.

Discussion:

Estimation of percentage of the efficacy of distraction achieved, helped in objectively evaluating the effectiveness of the intraoral mandibular distractors. A low complication rate and good esthetic and functional outcomes achieved in all the patients demonstrated the reliability of this treatment modality in the management of extreme mandibular deformities and severe facial asymmetries.

Skeletal Stem Cells-A Paradigm Shift in the Field of Craniofacial Bone Tissue Engineering

Defects of the craniofacial skeleton arise as a direct result of trauma, diseases, oncological resection, or congenital anomalies. Current treatment options are limited, highlighting the importance for developing new strategies to restore form, function, and aesthetics of missing or damaged bone in the face and the cranium. For optimal reconstruction, the goal is to replace "like with like." With the inherent challenges of existing options, there is a clear need to develop alternative strategies to reconstruct the craniofacial skeleton. The success of mesenchymal stem cell-based approaches has been hampered by high heterogeneity of transplanted cell populations with inconsistent preclinical and clinical trial outcomes. Here, we discuss the novel characterization and isolation of mouse skeletal stem cell (SSC) populations and their response to injury, systemic disease, and how their re-activation in vivo can contribute to tissue regeneration. These studies led to the characterization of human SSCs which are able to self-renew, give rise to increasingly fate restricted progenitors, and differentiate into bone, cartilage, and bone marrow stroma, all on the clonal level in vivo without prior in vitro culture. SSCs hold great potential for implementation in craniofacial bone tissue engineering and regenerative medicine. As we begin to better understand the diversity and the nature of skeletal stem and progenitor cells, there is a tangible future whereby a subset of human adult SSCs can be readily purified from bone or activated in situ with broad potential applications in craniofacial tissue engineering.

Conditioned media from mesenchymal stromal cells and periodontal ligament fibroblasts under cyclic stretch stimulation promote bone healing in mouse calvarial defects

BACKGROUND AIMS

When cells are exposed to stresses such as mechanical stimuli, they release growth factors and adapt to the surrounding environment H ere, we demonstrated that mechanical stimulation during culture affects the production of osteogenic and angiogenic factors.

METHODS

Human bone marrow derived mesenchymal stromal cells (hMSCs) and human periodontal ligament fibroblasts (HPLFs ) were cultured under cyclic stretch stimulation for 24 h. Collected of the cells and conditioned media (CM), the gene and protein expression levels of osteogenic and angiogenic factors were evaluated. CM was also evaluated for angiogenic activity and calc ification ability. In in vivo study, CM was administered to a mouse calvarial defect model and histologically and radiologically evaluated.

RESULTS

Quantitative real time polymerase chain reaction results showed that the expression of bone morphogenetic pro tein 2, 4 (BMP 2, 4), vascular endothelial growth factor A (VEGF A), and platelet derived growth factor AA (PDGF AA) was upregulated in the cyclic stretch stimulation group in comparison with the non stretch group in each cell type. Enzyme linked immunosor bent assay results revealed that the expression of BMP 2,4, VEGF A was upregulated in the cyclic stretch group in comparison with the non stretch group in each cell type. Only HPLFs showed significant difference in PDGF AA expression between the cyclic str etch and the non stretch group. Tube formation assay and Alizarin Red S staining results showed that angiogenic activity and calcification ability of CM was upregulated in the cyclic stretch stimulation group in comparison with the non stretch group in eac h cell type. CM was administered to the mouse calvarial defect model. Histological and radiological examination showed that the bone healing was promoted by CM from the cyclic stretch culture group. Immunohistological staining revealed that CM from cyclic stretch group have greater angiogenic effect than CM from the non stretch group.

CONCLUSIONS

These results indicate that osteogenesis was promoted by CM obtained under cyclic stretch stimulation through the increase of angiogenesis in the mouse calvarial defect model.

Long Term Speech Outcomes Following Midface Advancement in Syndromic Craniosynostosis

Midface advancement by distraction osteogenesis (DO) is commonly performed in patients with craniosynostosis for indications including midface hypoplasia, exorbitism, obstructive sleep apnea, class III malocclusion, and overall aesthetic facial deficiency. There is evidence to suggest that maxillary LeFort I advancement increases the risk of velopharyngeal dysfunction in the cleft palate population, yet few studies have investigated changes in speech following LeFort III or monobloc midface advancement in patients with syndromic craniosynostosis. The purpose of this study was to examine the effect of midface DO on speech as indicated by the Pittsburgh Weighted Speech Score in patients with Apert, Crouzon, and Pfeiffer Syndrome. Among 73 midface advancement cases performed during the study period, 19 cases met inclusion criteria. Overall, the highest post-advancement Pittsburgh Weighted Speech Score (PWSS) was significantly higher than the pre-advancement PWSS (0.52 versus 2.42, P = 0.01), indicating an acute worsening of VPI post-advancement. Specifically, the PWSS components nasal emission and nasality were significantly higher post-advancement than pre-advancement (nasal emission: 1.16 versus 0.21, P = 0.02) (nasality: 0.68 versus 0.05, P = 0.04). However, there was no significant difference between pre-advancement PWSS and the latest post-advancement PWSS (P = 0.31). Midface distraction is associated with an acute worsening of VPI post-operatively that is followed by improvement, and often resolution over time. Future work with additional patient accrual is needed to determine the effect of different advancement procedures and syndromes on VPI rates and profundity.

Le Fort III Distraction Osteogenesis Without Bicoronal Incision

PURPOSE

Recently, midfacial hypoplasia for syndromic craniosynostosi has been corrected by Le Fort III distraction osteogenesis. During conventional Le Fort III osteotomy, osteotomy is performed via bicoronal incision. In contrast, the authors have developed a technique for performing Le Fort III osteotomy using internal devices but without bicoronal incision.

PATIENTS AND METHODS

The authors performed the Le Fort III distraction technique in 22 patients. Of these, 17 patients underwent an approach using conventional coronal incision; the others underwent an approach without coronal incision. This new approach was performed using a McCord incision, a brow incision, and gingivo-buccal sulcus incisions. We then performed osteotomy and attached the internal device.

RESULTS

The age of patients ranged from 6 to 21 years (mean: 14.1 ± 5.0 years) and 6 to 38 years (mean: 19.6 ± 11.5 years) in the groups with or without coronal incision, respectively. Mean operative time was 410 ± 196 minutes in the group with coronal incision and 357 ± 121 minutes in the group without coronal incision. Mean blood loss (per unit of body weight) was 51.3 ± 38.5 and 33.9 ± 9.9 ml/kg) in the groups with or without coronal incision, respectively. There were no complications, except in the case of a 38-year-old patient, the oldest patient, who lost vision in the left eye after surgery.

CONCLUSION

A direct facial approach for Le Fort III distraction was useful because of its reduced operative time and blood loss. However, down fracture following incomplete osteotomy or inadequate dissection of the orbit may cause blindness. Consequently, this technique requires careful attention.

Leveling the Maxillary Occlusal Plane Without Orthodontic Appliances in Patients With Hemifacial Microsomia Using Unilateral Vertical Mandibular Distraction Osteogenesis

PURPOSE

To assess maxillary occlusal plane correction in patients with hemifacial microsomia (HFM) after vertical vector mandibular distraction osteogenesis (vMDO) without orthodontic appliances.

METHODS

A retrospective study was performed on consecutive patients with HFM and Kaban-Pruzansky type-II mandibular deformities who underwent unilateral vMDO by a single surgeon over an 18-month period. Patients with 12-months minimum clinical follow-up and postero-anterior (PA) cephalograms taken preoperatively and at a minimum of 3 months post-consolidation were included.

RESULTS

Five patients met inclusion criteria, 3 were female, median age was 13 years, median distraction length was 21.3 mm. Median radiographic follow-up was 5 months (range 3-38) post-consolidation. Median correction of the ramus height differential (difference between non-diseased and diseased side) was 97.3%. Median maxillary height differential correction was 72.2%. Median maxillary occlusal plane angle correction (towards zero) was 84.2%. Relative and absolute maxillary bone growth was greater on the diseased side (median 7.4%, 3.5 mm versus 2.8%, 1.4 mm). Dentoalveolar height decreased bilaterally in 4 of the 5 patients. Median chin point correction (towards midline) was 31.4%.

CONCLUSION

Unilateral vMDO without orthodontic appliances effectively corrected mandibular ramus height, leveled the maxillary occlusal plane, and preferentially increased maxillary bone growth on the diseased side in patients with HFM.

Growth observation and orthodontic treatment of a hemifacial microsomia patient treated with distraction osteogenesis

Hemifacial microsomia (HFM) patients may experience emotional withdrawal during their growth period due to their abnormal facial appearance. Distraction osteogenesis at an early age to improve their appearance can encourage these patients. Some abnormalities of the affected side can be overcome by distraction osteogenesis at an early age. However, differences in the growth rate between the affected and unaffected sides during the rest of the growth period are inevitable due to the characteristics of HFM. Therefore, re-evaluation should be performed after completion of growth in order to achieve stable occlusion through either orthognathic surgery or camouflage orthodontic treatment. An eight-year-old patient visited the clinic exhibiting features of HFM with slight mandibular involvement. He received phase I treatment with distraction osteogenesis and a functional appliance. Distraction osteogenesis was performed at the right ramus, which resulted in an open bite at the right posterior dentition. After distraction osteogenesis, a functional appliance and partial fixed appliance were used to achieve extrusion of the affected posterior dentition and settlement of the occlusion adjustment on the unaffected posterior dentition. The patient visited the clinic regularly for follow-up assessments, and at the age of 20 years, he showed facial asymmetry of the mandible, which had deviated to the right side. He received orthodontic treatment to improve the occlusion of his posterior dentition after the growth period. Without orthognathic surgery, stable occlusion and a satisfactory facial appearance were obtained through camouflage orthodontic treatment.

Evaluation of vertical ramus osteotomy for the surgical correction of unilateral mandibular posterior vertical insufficiency: Long-term follow-up results

PURPOSE

Unilateral posterior vertical insufficiency (PVI) is a growth defect of the mandibular condyle that results in a facial asymmetry. Various surgical procedures can be used to elongate the hypoplastic ramus. The aim of this study was to evaluate long-term aesthetic and architectural outcomes of vertical ramus osteotomy (VRO) in patients with unilateral PVI.

MATERIALS AND METHODS

Patients operated on with unilateral VRO were included in this retrospective study. Aesthetic and architectural parameters were evaluated on frontal photographs as well as on frontal and lateral cephalograms preoperatively, postoperatively, at 1-year and at the end of the follow-up.

RESULTS

A total of 48 patients were analyzed. The aesthetic assessment revealed significant correction of the chin deviation (CD) and of the lip commissural line tilt after VRO (p1 = 0.0038 and p2 = 0.0067, respectively) with stable results. The architectural analysis revealed significant improvement in the maxillary and mandibular occlusal planes, as well as the chin deviation (p < 0.0001). A tendency to relapse was noted for the mandibular canting and the CD during the follow-up. VRO allowed for a mean mandibular lengthening of 8.39 mm (ranging from 2.5 to 14 mm).

CONCLUSION

VRO allows for immediate restoration of the symmetry of the lower third of the face in patients with unilateral PVI. A revisional procedure may be needed due to a tendency for the chin deviation to relapse.

Surgical-Orthodontic Considerations in Subcranial and Frontofacial Distraction

Subcranial and frontofacial distraction osteogenesis have emerged as powerful tools for management of hypoplasia involving the upper two-thirds of the face. The primary goal of subcranial or frontofacial distraction is to improve the orientation of the upper face and midface structures (frontal bone, orbitozygomatic complex, maxilla, nasal complex) relative to the cranial base, globes, and mandible. The various techniques used are tailored for management of specific phenotypic differences in facial position and may include segmental osteotomies, differential vectors, or synchronous maxillomandibular rotation.

Maxillary Distraction Osteogenesis in a Patient With Osteogenesis Imperfecta

Osteogenesis imperfecta (OI) is characterized by brittle bones, premature hearing loss, blue sclera, dental abnormalities, and short stature. Maxillofacial pathology is marked in many OI patients and includes a high incidence of class III malocclusion secondary to a retrusive maxilla relative to both the mandible and cranial base.Review of literature shows that most of the orthognathic surgeries performed in the setting of OI are double jaw surgeries, in the form of maxillary advancement and mandibular setback. However, severe maxillary hypoplasia is usually not correctable with single-stage maxillary advancement. Distraction osteogenesis (DO) is a technique that relies on the normal healing process that occurs between controlled, surgically osteotomized bone segments and it is a relatively widely used technique in modern management of craniofacial conditions.Distraction osteogenesis has been reported in only several patients with OI. There is only 1 previously documented case of maxillary distraction in the craniofacial literature. The authors present here the successful management of a patient with OI and severe class III malocclusion using LeFort I osteotomy and DO with an external rigid distractor.At 12 months follow-up, the patient had no complications and maintained stable maxillary position with normal occlusion, improvement of facial appearance, obstructive airway symptoms, speech, and chewing.This case serves to reinforce the safety and efficacy of DO in patients with OI. The authors did not significantly change our distraction protocol and did not have any complications, therefore the authors believe that DO should be the preferable treatment technique for severe malocclusion in OI patient population.

Distraction osteogenesis in dog with a tooth-borne device: Histological and histomorphometric analysis

Background

The distraction osteogenesis (DO) is the biological process of new bone formation between the surfaces of bone segments gradually separated by incremental traction. However, the lack of solid experimental studies using the tooth-borne distractor does not allow comparing this technique with the classical procedures. This study aimed to establish the effect of two different activation protocols in new bone formation, with a new intraoral tooth-borne device for dog mandibular distraction osteogenesis.

Material and Methods

Nine beagle dogs were split into 3 similar groups, Group A the control, Group B subjected to two daily activations of 0.5 mm and Group C subjected to a single daily activation of 1 mm. The distraction period was 10 days followed by a 12 weeks consolidation period. Samples where then processed and embedded in methylmethacrylate and ground to a thickness of 20µm. Toluidine blue stains were done on all specimens and histological and histomorphometric evaluation of bone tissue formed within distraction gap was performed. The statistical analysis in this manuscript was performed with IBM®-SPSS® v.20 statistics software and R software version 3.1.0. The level of significance adopted was 5 % (α=0.05).

Results

No statistically significant difference was detected by histomorphometric evaluation between the two experimental groups in what concerns the bone volume. However, significant differences were found in the coefficients of variation between the medial and buccal areas, and the buccal and lingual areas.

Conclusions

This study shows that the mandible can be lengthened successfully using a tooth-borne distractor. Moreover, it suggested that a decrease from once to twice-daily activations might negatively change the quality and structure of newly formed bone and prompt it to instability. Key words:Retrognathia, bone regeneration, osteogenesis, distraction.

The Effect of Photobiomodulation on Distraction Osteogenesis

Distraction osteogenesis (DO) is a surgical procedure to increase bone height in different body parts. DO includes a surgical incision, wherein the bone is cut and a device is installed for further separation of the two ends by gradual unscrewing of the device screw. New bone gradually forms and fills the gap, and the bone height increases as such. Photobiomodulation (PBM) or low-level laser therapy (LLLT) enhances the formation of soft and hard tissue such as bone and can, therefore, accelerate the process of DO and shorten the duration of different surgical phases of DO such as latency, activation, and consolidation. Different laser types with variable exposure settings and protocols have been used for this purpose. The gallium-aluminum-arsenide (GaAlAs) diode laser is the most commonly used laser type for LLLT. This study reviews 18 published articles on the effects of LLLT on DO and summarizes their findings to further elucidate this topic.

Fat Grafting in Managing Craniofacial Deformities

BACKGROUND

The successful correction of craniofacial contour deformities remains a major challenge in plastic surgery. This article reviews important concepts and strategies for craniofacial fat grafting and presents a SOBRAPAR Hospital algorithm focused on achieving craniofacial contour symmetry as early as possible without compromising function.

METHODS

Principle-based methods (i.e., anatomical facial fat compartments, fluid accommodation model, multistage site-specific craniofacial fat grafting, and structural fat-grafting technique) were itemized into an algorithm to aid in planning and selecting the best surgical approach (i.e., bone and/or soft tissue procedures) in order to obtain craniofacial contour symmetry.

RESULTS

The treatment plan and choice of surgical technique implemented to address bone and/or or soft tissue deformities were determined by specific diagnosis, patient age at presentation, and functional status. Bony reconstruction in skeletally immature patients is reserved solely for those patients with functional issues.

CONCLUSION

By adopting principle-based methods and fat compartment theory, we are able to achieve craniofacial contour symmetry and aesthetically pleasing outcomes without compromising function.

Fak silencing impairs osteogenic differentiation of bone mesenchymal stem cells induced by uniaxial mechanical stretch

Background/purpose

Mechanical stretch plays a key role in promoting proliferation and differentiation of bone marrow mesenchymal stem cells (BMSCs) in distraction osteogenesis (DO). A better understanding of how the extracellular biomechanical stimulation is transferred to intracellular signal expression will benefit DO. Focal adhesion kinase (FAK) is a key factor in integrin signaling pathway. However, little is known about the effect of integrin-FAK signaling during the process of stretch induced osteogenic differentiation of BMSCs.

Materials and methods

A specific short hairpin RNAs (shRNAs) lentiviral expression vector was used to silence Fak gene and a well-established in vitro uniaxial dynamic stretching device was applied to stimulate DO. Fak silencing was confirmed by fluorescence microscopy and the detection of Fak mRNA and FAK, p-FAK protein expression. Alkaline phosphatase (ALP) activity, expression of osteogenic differentiation markers - runt-related transcription factor 2 (RUNX2/Runx2) and alkaline phosphatase (Alp) together with integrin upstream signal transduction molecules integrin beta-1 (ITGB1/Itgb1) and downstream signal transduction molecules integrin-linked kinase (ILK) were detected after the stretch.

Results

The results showed that mechanical stretch in control groups significantly induced the osteogenic differentiation of BMSCs with increased ALP activity, expression of RUNX2/Runx2 and Alp, together with upregulated ITGB1/Itgb1 and ILK, which all vanished in Fak silencing group.

Conclusion

Silencing of the Fak gene inhibited the osteogenic differentiation of rat BMSCs induced by in vitro mechanical stretch through integrin signaling pathway.

Sensory Nerves Affect Bone Regeneration in Rabbit Mandibular Distraction Osteogenesis

Objectives: To investigate the effects of inferior alveolar nerve on new bone formation in rabbit mandibular distraction osteogenesis. Methods: 20 New Zealand White rabbits underwent bilateral distraction osteogenesis with a rate of 1 mm/day. The inferior alveolar nerve of one side was resected under the surgical microscope, with the inferior alveolar vascular intact. The contralateral side received sham operation. The rabbits were sacrificed at consolidation time of 28 days. The regenerate callus underwent radiograph examination, dual-energy X-ray absorptiometry, haematoxylin and eosin staining and histomorphometric analysis. A paired t-test was performed using SPSS 16.0 software package. Results: The BMD of the new bone in the distraction gap on the denervation side of mandibular was significantly lower (P<0.05) than on the control side. The histological investigation showed that the bone trabeculae were dis-arrayed containing dispersed cartilage cells on the denervation side, whereas the bone trabeculae were orderly with rich blood vessels and no cartilage cell on the control side. Both new bone volume and the thickness of new trabeculae were significantly lower on the denervation side than on the control side (P < 0.05). Conclusion: The loss of the sensory nerves could result in a decrease of the new bone quality during the mandibular distraction osteogenesis.

Radioprotection With Amifostine Enhances Bone Strength and Regeneration and Bony Union in a Rat Model of Mandibular Distraction Osteogenesis

BACKGROUND

Using distraction osteogenesis (DO) to regenerate robust endogenous bone could greatly enhance postoncologic reconstruction of head and neck cancer. However, radiation (XRT) corrosive effects still preclude DO's immense potential. We posit that adjunctive pretreatment with the radioprotectant amifostine (AMF) can optimize wound healing and allow for successful DO with quantifiable enhancements in bony union and strength despite previous surgical bed irradiation.

METHODS

Two groups of murine left hemimandibles were exposed to a human equivalent radiation dosage fractionated over 5 daily doses of 7 Gy. AMF-XRT-DO (n = 30) received AMF before radiation, whereas XRT-DO (n = 22) was untreated. All animals underwent left hemimandibular osteotomy and external fixator placement, followed by distraction to a 5.1-mm gap. Left hemimandibles were harvested and mechanically tested for parameters of strength, yield, and breaking load.

RESULTS

Radiation-related complications such as severe alopecia were significantly increased in XRT-DO compared with the AMF-treated group (P = 0.001), whereas infection and death were comparable (P = 0.318). Upon dissection, bony defects were grossly visible in XRT-DO distraction gap compared with AMF-XRT-DO, which exhibited significantly more complete unions (P = 0.004). Those results were significantly increased in the specimens prophylactically treated with AMF (yield: 39.41 N vs 21.78 N, P = 0.023; breaking load: 61.74 N vs 34.77 N, P = 0.044; respectively).

CONCLUSIONS

Our study revealed that AMF enhances biomechanical strength, regeneration, and bony union after radiation in a murine model of DO. The use of prophylactic AMF in combination with DO offers the promise of an alternative reconstructive option for patients afflicted with head and neck cancer.

Current Trends in Surgical Airway Management of Neonates with Robin Sequence

Background

Robin sequence is defined by the clinical triad of micrognathia, glossoptosis, and upper airway obstruction, and is frequently associated with cleft palate and failure to thrive. Though the efficacy of certain surgical interventions to relieve airway obstruction has been well established, algorithms dictating decision making and perioperative protocols are poorly defined.

Methods

A 22-question survey was sent via e-mail to members of the American Cleft Palate-Craniofacial Association and International Society of Craniofacial Surgeons. Questions were related to surgeon experience in treating neonates with Robin sequence, and specific perioperative protocols.

Results

One hundred fifty-one responses were collected. Most respondents were surgeons practicing in North America(82.8%), in a university hospital setting (81.5%) and had completed a fellowship in pediatric plastic surgery or craniofacial surgery (76.2%). Preoperative protocols varied widely by years in training and location of practice. Although 78.8% of respondents always performed direct laryngoscopy, only 49.7% of respondents routinely obtained preoperative polysomnography. Mandibular distraction osteogenesis was the most common primary surgical airway intervention reported by 74.2%, with only 12.6% primarily utilizing tongue-lip adhesion. Slightly less than half of respondents ever performed tongue-lip adhesion. Operative selection was influenced by surgeon experience, with 80% of those in practice 0-5 years primarily utilizing mandibular distraction, compared with 56% of respondents in practice >15 years.

Conclusions

This study documents wide variations in preoperative, operative, and postoperative protocols for the surgical airway management of neonates with severe Robin sequence. These results underscore the need to acquire more objective data, to compare different protocols and outcome measures.

Versatility of uniplanar prearthoplastic distraction osteogenesis in the correction of post-ankylosis facial deformities-a report of five different cases

PURPOSE

Unilateral or bilateral ankylosis can lead to severe micrognathia and facial deformity that requires multiple, often, staged surgical corrections. To date, there is no ideal treatment modality that satisfactorily corrects the complex anatomy, restores the ramal height, and corrects the micrognathia and microgenia. Distraction osteogenesis has been acclaimed as a successful modality for the treatment of such deformities. It is a cost-effective approach with low morbidity and less relapse thus providing better functional and esthetic outcomes. It allows the surgeon to correct the deformity in various planes by using various devices by changing osteotomy designs and vectors, with simultaneous hard tissue and soft tissue reconstruction.

PATIENTS AND METHODS

Here, we present a series of five cases where different types of distraction osteogenesis were combined with various other procedures to correct post-ankylotic facial asymmetry. In one case, simultaneous maxillo-mandibular distraction [Molina's technique] was used.

RESULTS

All patients showed significant improvement in function and esthetics. Outcome assessment was made using clinical photographs and radiographs.

CONCLUSION

Pre-arthroplastic distraction osteogenesis is a versatile cost effective approach that can be customized for every patient based on their needs.

Maxillary distraction osteogenesis versus orthognathic surgery for cleft lip and palate patients

BACKGROUND

Cleft lip and palate is one of the most common birth defects and can cause difficulties with feeding, speech and hearing, as well as psychosocial problems. Treatment of orofacial clefts is prolonged; it typically commences after birth and lasts until the child reaches adulthood or even into adulthood. Residual deformities, functional disturbances, or both, are frequently seen in adults with a repaired cleft. Conventional orthognathic surgery, such as Le Fort I osteotomy, is often performed for the correction of maxillary hypoplasia. An alternative intervention is distraction osteogenesis, which achieves bone lengthening by gradual mechanical distraction. This review is an update of the original version that was published in 2016.

OBJECTIVES

To provide evidence regarding the effects and long-term results of maxillary distraction osteogenesis compared to orthognathic surgery for the treatment of hypoplastic maxilla in people with cleft lip and palate.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 15 May 2018), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2018, Issue 4), MEDLINE Ovid (1946 to 15 May 2018), Embase Ovid (1980 to 15 May 2018), and LILACS BIREME Virtual Health Library (Latin American and Caribbean Health Science Information database; from 1982 to 15 May 2018). The US National Institutes of Health Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing maxillary distraction osteogenesis to conventional Le Fort I osteotomy for the correction of cleft lip and palate maxillary hypoplasia in non-syndromic cleft patients aged 15 years or older.

DATA COLLECTION AND ANALYSIS

Two review authors assessed studies for eligibility. Two review authors independently extracted data and assessed the risk of bias in the included studies. We contacted trial authors for clarification or missing information whenever possible. All standard methodological procedures expected by Cochrane were used.

MAIN RESULTS

We found six publications involving a total of 47 participants requiring maxillary advancement of 4 mm to 10 mm. All of them related to a single trial performed between 2002 and 2008 at the University of Hong Kong, but not all of the publications reported outcomes from all 47 participants. The study compared maxillary distraction osteogenesis with orthognathic surgery, and included participants from 13 to 45 years of age.Results and conclusions should be interpreted with caution given the fact that this was a single trial at high risk of bias, with a small sample size.The main outcomes assessed were hard and soft tissue changes, skeletal relapse, effects on speech and velopharyngeal function, psychological status, and clinical morbidities.Both interventions produced notable hard and soft tissue improvements. Nevertheless, the distraction group demonstrated a greater maxillary advancement, evaluated as the advancement of Subspinale A-point: a mean difference of 4.40 mm (95% CI 0.24 to 8.56) was recorded two years postoperatively.Horizontal relapse of the maxilla was significantly less in the distraction osteogenesis group five years after surgery. A total forward movement of A-point of 2.27 mm was noted for the distraction group, whereas a backward movement of 2.53 mm was recorded for the osteotomy group (mean difference 4.8 mm, 95% CI 0.41 to 9.19).No statistically significant differences could be detected between the groups in speech outcomes, when evaluated through resonance (hypernasality) at 17 months postoperatively (RR 0.11, 95% CI 0.01 to 1.85) and nasal emissions at 17 months postoperatively (RR 3.00, 95% CI 0.14 to 66.53), or in velopharyngeal function at the same time point (RR 1.28, 95% CI 0.65 to 2.52).Maxillary distraction initially lowered social self-esteem at least until the distractors were removed, at three months postoperatively, compared to the osteotomy group, but this improved over time and the distraction group had higher satisfaction with life in the long term (two years after surgery) (MD 2.95, 95% CI 014 to 5.76).Adverse effects, in terms of clinical morbidities, included mainly occlusal relapse and mucosal infection, with the frequency being similar between groups (3/15 participants in the distraction osteogenesis group and 3/14 participants in the osteotomy group). There was no severe harm to any participant.

AUTHORS' CONCLUSIONS

This review found only one small randomised controlled trial concerning the effectiveness of distraction osteogenesis compared to conventional orthognathic surgery. The available evidence is of very low quality, which indicates that further research is likely to change the estimate of the effect. Based on measured outcomes, distraction osteogenesis may produce more satisfactory results; however, further prospective research comprising assessment of a larger sample size with participants with different facial characteristics is required to confirm possible true differences between interventions.

Contribution of the periosteum to mandibular distraction

Mandibular distraction is a surgical process that progressively lengthens bone. To improve the distraction procedure and devices, the load of distraction and the mechanical strain of soft tissues during the process must be determined. We tested the assumption that it could be the periosteum primarily opposing distraction. Therefore we assessed the mechanical properties of the human mandibular periosteum and compared the stress-strain data with the torque measured on the activator during a cadaveric mandibular distraction. A 20 mm horizontal mandibular distraction was performed in 7 cadavers using standard distractors. Torque was measured with a torquemeter placed on the activation rods of the devices, providing a load (L_t) for each millimeter of distraction. In parallel, 18 periosteum samples were harvested from 9 cadaver mandibles. Uniaxial tensile tests were performed on the specimens and an estimated load (L_c) was calculated using periosteal stress-strain data and mandibular dimensions. During the distraction process, we observed an increase of the load L_t from 11.6 to 50.6 N. The periosteum exhibited a nonlinear viscoelastic stress-strain relationship, typical of biological tissues composed of collagen and elastin. The median L_c and L_t were not significantly different for the first millimeter of distraction. We demonstrated the periosteum is primarily responsible for opposing the distraction load.