Current practice of distraction osteogenesis for craniofacial anomalies in Europe: a web based survey

Biomechanical analysis of teeth movement during the repair of mandibular defects using transport disk distraction osteogenesis

INTRODUCTION

Teeth movement or rotation is one of the complications of mandibular defect repair using transport disk distraction osteogenesis (TDDO). However, the mechanical reasons are not clearly understood.

MATERIAL AND METHODS

To evaluate the biomechanical factors associated with teeth movements during mandibular defect repair with TDDO, a finite element model created from computed tomographic images of the human mandible was adopted to evaluate teeth displacement and the Von Mises stress distribution on the periodontal ligament resulting from the transport disk for teeth subjected to TDDO loading.

RESULTS

Under a displacement of 0.5 mm to the fixed arm of the transport disk, the teeth on the disk moved away from the distraction. The stress on the periodontal ligament was highest (60 KPa) around the distal neck. Upon the application of 150 g of resistance, the entire tooth moved in the same direction and the isoline gradient was almost parallel to the long axis of the tooth. Although the stress was distributed similarly; it decreased to 0.117 KPa geometrically.

DISCUSSION

When mandibular defects are repaired with TDDO, the transport disk and anti-distraction forces contribute to the reversal movement or rotation of the teeth, which may become immobility when antagonistic forces are applied in the same direction.

Distraction force promotes the osteogenic differentiation of Gli1+ cells in facial sutures via primary cilia-mediated Hedgehog signaling pathway

BACKGROUND

Trans-sutural distraction osteogenesis (TSDO) involves the application of distraction force to facial sutures to stimulate osteogenesis. Gli1+ cells in the cranial sutures play an important role in bone growth. However, whether Gli1+ cells in facial sutures differentiate into bone under distraction force is unknown.

METHODS

4-week-old Gli1ER/Td and C57BL/6 mice were used to establish a TSDO model to explore osteogenesis of zygomaticomaxillary sutures. A Gli1+ cell lineage tracing model was used to observe the distribution of Gli1+ cells and explore the role of Gli1+ cells in facial bone remodeling.

RESULTS

Distraction force promoted bone remodeling during TSDO. Fluorescence and two-photon scanning images revealed the distribution of Gli1+ cells. Under distraction force, Gli1-lineage cells proliferated significantly and co-localized with Runx2+ cells. Hedgehog signaling was upregulated in Gli1+ cells. Inhibition of Hedgehog signaling suppresses the proliferation and osteogenesis of Gli1+ cells induced by distraction force. Subsequently, the stem cell characteristics of Gli1+ cells were identified. Cell-stretching experiments verified that mechanical force promoted the osteogenic differentiation of Gli1+ cells through Hh signaling. Furthermore, immunofluorescence staining and RT-qPCR experiments demonstrated that the primary cilia in Gli1+ cells exhibit Hedgehog-independent mechanosensitivity, which was required for the osteogenic differentiation induced by mechanical force.

CONCLUSIONS

Our study indicates that the primary cilia of Gli1+ cells sense mechanical stimuli, mediate Hedgehog signaling activation, and promote the osteogenic differentiation of Gli1+ cells in zygomaticomaxillary sutures.

Growth characteristics and classification systems of hemifacial microsomia: a literature review

BACKGROUND

Hemifacial microsomia is characterized by the hypoplasia of the mandible and temporomandibular joint, involving a variety of abnormalities of the craniofacial area. Since it gradually worsens as patients grow, it is necessary to understand the characteristics of facial bone growth and facial deformity in hemifacial microsomia patients in order to determine appropriate treatment timing and treatment methods.

MAIN BODY

Appropriate classification of hemifacial microsomia would facilitate accurate diagnosis, selection of treatment methods, and prognosis prediction. Therefore, in this article, we review previously published hemifacial microsomia classification and provide an overview of the growth of the facial skeleton and the characteristics of hemifacial microsomia-related facial deformities. The OMENS system is the most comprehensive classification method based on the characteristics of hemifacial microsomia deformity, but it needs to be improved to include malar/midface abnormalities and nerve involvement. In hemifacial microsomia, growth is progressing on the affected side, but to a lesser degree than the unaffected side. Therefore, surgical intervention in growing patients should be performed selectively according to the severity of deformity.

CONCLUSION

Understanding growth patterns is important to develop appropriate treatment protocols for correcting asymmetry in adult patients and to minimize secondary anomalies in growing patients.

Bilateral Biplanar Distraction Osteogenesis in Facial Deformity Secondary to Temporomandibular Ankylosis

Background

The purpose of this single-centre prospective clinical study was to evaluate the correction of severe facial deformity and Obstructive sleep apnoea hypopnoea syndrome (OSAHS) in 22 patients aged from 9 to 42 years (mean 20.09) of bilateral Temporomandibular joint ankylosis.

Materials and Methodology

Patients underwent multisegment distraction using external bilateral bidirectional distractors. Facial deformity was evaluated clinically in terms of mouth opening and neck chin angle and cephalometrically in terms of corpus length (gonion-pogonion), ramal height (articulare-gonion), chin deficiency (N perpendicular to Pog and SNB). OSAHS was evaluated through Epworth sleepiness scale, Berlin's questionnaire, pharyngeal airway space, apnoeic hypoapnoeic index, oxygen desaturation index, average arterial oxygen saturation and minimal fall in O2 saturation. Patients were followed up for a period of 13-74 months (mean 28.68).

Results

Statistically highly significant results were obtained in all parameters. Complications encountered were pin infection (13.63%), loosening of pins (4.5%), wound dehiscence (9.09%), tooth fracture (4.5%) and parotid fistula (9.09%). Intermediate segment necrosis and vector loss were not observed.

Conclusion

This study is a large case series using two corticotomy cuts for external bilateral bidirectional distracters with concomitant neo callous moulding in patients both pre- and post-ankylosis release. It is extremely efficient in correcting mandibular corpal and ramal deficiency as well as improving OSAHS.

Reducing the Burden of Care: Multidisciplinary Management of Late-Manifested Crouzon Syndrome—A Case Report

The therapy of patients with Crouzon syndrome involves a multidisciplinary team. In most cases, this therapy is extensive, time-consuming, and exhausting for the patient. This case report illustrates a temporally coordinated therapy plan that succeeds in reducing the burden of care. Showing typical extraoral characteristics of Crouzon syndrome, the patient had a frontal and left-sided crossbite, and impaction of the maxillary canines. Multidisciplinary therapy included the extraction of multiple teeth, midface distraction at Le Fort III level, and alignment of the impacted teeth. Before starting, during, and after completion of the treatment, the patient’s oral health-related quality of life was assessed using COHIP-19. The combination of different treatment steps significantly reduced the duration of therapy. The therapy improved not only the patient’s oro- and craniofacial function, but also the patient’s facial appearance in a short treatment period. The patient’s quality of life improved considerably during this time. In the treatment of severe craniofacial anomalies, the highest priority should be given to keeping the burden of care low. All measures should encourage young patients’ appropriate psychosocial development despite extensive therapies, ensuring at the same time medically satisfactory treatment results.

Latency phase in mandibular distraction osteogenesis: a systematic review in animal models

The aim of the present study was to perform a systematic review of the need for the latency period in distraction osteogenesis to obtain adequate bone formation. Searches were performed in the Web of Science, Pubmed/MEDLINE, Scopus, and Cochrane electronic databases. Nine articles were selected for qualitative analysis. Quality assessment was performed using the 10-item SYRCLE tool. Clinical stability was evaluated in two articles, histology was analysed in seven, histomorphometry was analysed in three, and mechanical testing was used in two. The results favoured the five-day latency group in two studies and the seven-day latency group in one. No differences were found between latency and no-latency groups in six studies. A latency period greater than seven days did not provide any additional benefit. Important risks of bias were found in all articles. Some of the results were influenced by uncontrolled intervening factors, such as consolidation time. The need for a latency period for distraction osteogenesis in animal models is not yet clear. Caution must be exercised when extrapolating the results of animal protocols to applications with humans in the clinical setting.

Development and surgical application of a custom implant that enables a vertical vector of mandibular distraction

Hemifacial microsomia is a congenital malformation that involves the underdevelopment of the mandible and the ear leading to facial asymmetry. Distraction osteogenesis is the gold standard surgical procedure for severe cases of hemifacial microsomia in which two sectioned bone parts are lengthened gradually to promote bony infill. The final shape of the bone depends on the position of the distractor and the vector of distraction. This article presents a complex clinical case of a 7-year-old patient with severe hemifacial microsomia that required distraction to correct mandibular asymmetry. Digital technology was applied to virtually plan the surgery pre-operatively. Optimal symmetrisation required a vertical vector of distraction that none of the 'off-the-shelf' distractors could provide. Consequently, a three-dimensional printed titanium implant was designed as a spacer to be attached to the inferior plate of a standard distractor, allowing the achievement of a vertical vector. By adding the spacer, the inferior footplate of the distractor was not directly fixed to bone and the vector of distraction was not dictated by the anatomical contour of the patient but by the shape of the spacer. Surgical guides were created to translate the virtual plan to the operating room. The guides prevented potential damage to tooth buds and the inferior alveolar nerve. This article describes the three-dimensional computer-aided design and additive manufacture of the custom devices that delivered the following: (1) symmetrisation of the mandible after distraction surgery without manipulation of the healthy side of the mandible; (2) a feasible and safer surgical solution; and (3) an innovative method that enables a wider range of vectors of distraction, bringing new prospects to the treatment of distraction osteogenesis in the future.

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.

Anterior Skull Base and Pericranial Flap Ossification after Frontofacial Monobloc Advancement

BACKGROUND

Frontofacial monobloc advancement creates a communication between the anterior cranial fossa and nasal cavities. To tackle this issue, transorbital pericranial pedicled flaps are routinely performed in the authors' center. This study aimed to assess the postoperative ossification of the anterior skull base and pedicled flaps following frontofacial monobloc advancement, and to identify factors influencing this ossification.

METHODS

Measurements of the skull base only and of the ossified pedicled flaps together with the skull base were performed on computed tomographic scans at the nasofrontal and the nasoethmoid frontal junctions. The total thickness of the skull vault was measured and a qualitative defect score for the anterior skull base was computed.

RESULTS

Twenty-two patients who underwent frontofacial monobloc advancement at a median age of 3.1 years (range, 1.9 to 3.6 years) were included: 14 with Crouzon, five with Pfeiffer, and three with Apert syndrome. One year and 5 years after surgery, the distraction gap was completely ossified in the anterior skull base midline in all patients. Ossified pedicled flaps together with the skull base were thicker in patients than in controls at these two time points (p < 0.005 and p < 0.02). Patients with Pfeiffer syndrome had a significantly thicker skull base only and ossified pedicled flaps together with the skull base thicknesses (p = 0.01 and p = 0.03) and lower defect scores than patients with Crouzon or Apert syndrome (p = 0.03) 1 year postoperatively.

CONCLUSION

As ossification of the pedicled flaps and total reossification of the anterior skull base midline were observed in all patients, the authors indicate that performing pedicled flaps in frontofacial monobloc advancement surgery could promote the reossification of the anterior skull base.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Long-Term Skeletal Changes After Maxillary Distraction Osteogenesis in Growing Children With Cleft Lip/Palate

PURPOSE

To systematically evaluate the skeletal changes after maxillary distraction osteogenesis (DO) in growing patients with cleft lip with or without cleft palate (CL/P).

MATERIALS AND METHODS

Electronic databases, gray literature, and reference list searches were conducted. Articles reporting prospective and retrospective studies that included patients <16 years old (N ≥ 6) who had received DO surgery for correction of a midfacial hypoplasia due to CL/P, and the period of follow-up persisted >1 year were reviewed. The original articles were evaluated by 2 investigators to ensure that they met the selection criteria. A methodologic quality assessment tool was used to evaluate the quality of selected studies. Twenty-six studies met the initial search criteria, and 9 articles included 101 growing patients with maxillary hypoplasia due to CL/P who received DO surgery were finally selected and analyzed.

RESULTS

The results showed that long term after maxillary advancement with DO, the horizontal relapse in A-point was <15% in 3 studies, 20% to 25% in 1 study, 30% to 35% in 3 studies, and >40% in 1 study. Totally, the range of horizontal relapse in A-point was 11.9% to 45.9%. Similarly, the relapse in SNA angle was <30% in 1 study, 30% to 40% in 3 studies, and >40% in 2 studies. Totally, the range of relapse in SNA was 25.7% to 77%. Two studies showed that the vertical relapse in A-point were 137% and 208%, and in the PNS point were 65% and 62.7%.

CONCLUSION

Although findings demonstrated that DO is an effective treatment method for severe maxillary hypoplasia in growing patients with CL/P, there is a relatively high amount of skeletal relapse both in horizontal and vertical dimension. Thus, the first proposed alternative for CL/P patients would be to select the correct primary procedure to decrease damage and avoid unnecessary scars. Then appropriate preoperative and postoperative care is necessary to prevent postoperative relapse. In addition, overcorrection also may be a possible alternative for compensation of postoperative relapse.

Simultaneous maxillomandibular distraction osteogenesis in hemifacial microsomia: Report of 7 cases

INTRODUCTION

The goal in treating Hemifacial microsomia (HFM) is to improve facial symmetry, allow functional jaw movement, obtain stable occlusion, and achieve patient satisfaction. This study was planned with an aim to assess the outcome of simultaneous maxillomandibular distraction osteogenesis in hemifacial microsomia.

MATERIAL & METHODS

Seven patients with hemifacial microsomia were included in this study and demographic data was obtained. Simultaneous maxillo-mandibular distraction was planned for correction of maxillary cant, vertical ramal lengthening and midline, by performing unilateral mandibular osteotomy in ramus and distractor fixation, a Le Fort I osteotomy, with fixation at contralateral zygomatic buttress and intermaxillary elastics. Derriford Appearance Scale was used to measure individual responses to address problems of appearance.

RESULTS

6 males and 1 female, with age range 18-26 years, mean 22.14 were included in the study. Maxillary occlusal cant varied from 4-16°, mean 9.85° and distraction achieved ranged from 12-19 mm, mean 15.57. Preoperatively DAS score ranged from 42-61, mean 51.7 and improved to 10-27, mean 18.4. 100% success was achieved in 5 cases, while other two showed 96% and 99% success.

CONCLUSION

Simultaneous maxillomandibular distraction osteogenesis improves facial esthetics and obviates the need for postoperative orthodontics, minimizing the treatment period.

Role of distraction osteogenesis in craniomaxillofacial surgery

In the field of orthopedic surgery, distraction osteogenesis (DO) is well known for limb lengthening procedures or secondary corrective surgery in the fracture treatment of the extremities. The principle of gradual expansion of bone and surrounding soft tissues as originally described by G.A. Ilizarov is also applicable to the craniofacial skeleton when growth deficiency is present, and the patients affected by craniofacial or dentofacial anomalies may require distraction procedures. The surgical management is comparable. After osteotomy and the mounting of a specific craniomaxillofacial distraction device, active distraction is started after a latency phase of several days, with a distraction rate of up to 1 mm/day until the desired amount of distraction has been achieved. Subsequently, distractors are locked to provide appropriate stability within the distraction zone for callus mineralization during the consolidation phase of 3–6 months, which is followed by a further remodeling of the bony regenerate. After 14 years of clinical application, the role and significance of craniomaxillofacial DO are discussed after reviewing the files of all patients who were treated by craniomaxillofacial distraction procedures.

[Rational use of distraction osteogenesis in craniofacial surgery]

Distraction osteogenesis, initially developed by Ilizarov for limb, is the tissular extension caused by the progressive space of the osseous pieces following an osteotomy. Distraction is osteogenesic and histogenic. Twenty-five years ago, at the instigation of McCarthy, this technique was used to handle the craniofacial malformations in the various floors of the face : mandibular, mediofacial and cranial. The most wide-spread protocols respect a latency period from 0 to 7 days, a rhythm of distraction from 1 to 2mm a day in 2 at 4 times and a period of consolidation from 4 to 8 weeks. Distraction is the result of the inventiveness of the pioneers then the work to always adapt to the multiple complex clinical situations. The surgeon has to choose between internal or external materials allowing a mono- or multi-vectorial extension, in osseous and/or dental anchoring. The mandibular distraction is very effective for the treatment of the secondary obstructive syndromes in the unilateral or bilateral severe hypomandibular malformations. She also allows desobstruction of the superior airways within the framework of the mediofacial hypoplasies as well as the secondary treatment of the growth defects in cleft lips and palates. Finally, the distraction osteogenesis enhanced reliability of the fronto-facial advancement in early and secondary treatment of craniofaciosynostosis. This is a real support of the facial growth, which has to be included in a plan of global treatment.

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.

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

We searched the following electronic databases: Cochrane Oral Health's Trials Register (to 16 February 2016), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2016, Issue 1), MEDLINE Ovid (1946 to 16 February 2016), Embase Ovid (1980 to 16 February 2016), LILACS BIREME (1982 to 16 February 2016), the US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov) (to 16 February 2016), and the World Health Organization (WHO) International Clinical Trials Registry Platform (to 16 February 2016). There were no restrictions regarding language or date of publication in the electronic searches. We performed handsearching of six speciality journals and we checked the reference lists of all trials identified for further studies.

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.

Crouzon syndrome: Virtual planning of surgical treatment by application of internal distractors

Crouzon syndrome is one of the frequent pathologies within craniosynostosis syndrome. Current progress in computers and biotechnologies allows improving surgical approach and forecasting final result of reconstruction as well. We present a case of successful surgical treatment of Crouzon syndrome, done by application of virtual planning allowing determining “monobloc” features, type of reconstruction and distraction protocol as well. A 20-year-old female had presented with craniofacial deformity. Clinical and radiological investigation revealed Crouzon syndrome. The “monobloc” creation, cranioplasty and internal distractors positioning, direction and schedule of advancement were done according to preoperative virtual planning data achieved by Materialise Mimics Research software. Nine months postoperative functional and esthetic result and radiological findings showed to be reasonable. That application of virtual simulation significantly allows to determine best direction of distraction and improves postoperative outcomes of surgical treatment of Crouzon syndrome.

Contemporary Correction of Dentofacial Anomalies: A Clinical Assessment

Contemporary computer-assisted technologies can support the surgical team in the treatment of patients affected by dentofacial deformities. Based on own experiences of 350 patients that received orthognathic surgery by the same team from 2007 to 2015, this clinical review is intended to give an overview of the results and risks related to the surgical correction of dentofacial anomalies. Different clinical and technological innovations that can contribute to improve the planning and transfer of corrective dentofacial surgery are discussed as well. However, despite the presence of modern technologies, a patient-specific approach and solid craftsmanship remain the key factors in this elective surgery.

Rigid External Distractor Aided Conventional Le Fort III Osteotomy Advancement in Adult With Severe Midfacial Hypoplasia

BACKGROUND

Management of severe midfacial hypoplasia is still a challenge for craniofacial team, adult patients with syndromic midfacial hypoplasia made the situation even worse. The authors present the clinical result in an adult patient with Crouzon syndrome treated by rigid external distractor aided conventional Le Fort III procedure.

METHODS

A 26-year-old patient with Crouzon syndrome presented with severe midfacial hypoplasia, a negative overjet of -17 mm, exorbitism, airway obstruction, and masticatory problem, while chief complaint of the patient was abnormal appearance. After Le Fort III osteotomy, rigid external distractor and distraction hooks were fixed. With the aid of rigid external distractor, the midfacial mass was immediately advanced to a desired position, allograft bone grafted in the gaps, and microplate fixed. The device was removed 3 weeks later when the advanced midface was stable.

RESULTS

Point A was advanced by 18.6 mm in horizontal and displaced superiorly 0.5 mm in vertical at the time of device removal. Point A moved backward 1.5 mm and upward 0.3 mm at 2-year follow-up. A good and balanced facial profile was obtained in a short treatment period. Airway obstruction symptoms and exorbitism were relieved.

CONCLUSIONS

The midfacial advancement achieved by rigid external distractor aided conventional Le Fort III osteotomy is a stable, controllable, and timesaving procedure. This technique may become an important choice for adult patients with severe midfacial hypoplasia.

Complex craniofacial advancement in paediatric patients: Piezoelectric and traditional technique evaluation

PURPOSE

The piezoelectric device allows bone cutting without damaging the surrounding soft tissues. The purpose of this study was to assess the role of this surgical instrument in paediatric craniofacial surgery in terms of safety and surgical outcomes.

METHODS

Thirteen consecutive paediatric patients underwent craniofacial Le Fort osteotomies type III and IV. The saw was used on the right side in seven patients and on the left side in six patients; the piezoelectric instrument was used on the right side in six patients and on the left side in seven patients. Intraoperative blood loss, surgical procedure length, incision precision, postoperative haematoma and swelling, and nerve impairment were evaluated to compare the outcomes of both procedures.

RESULTS

A longer surgical procedure was observed in 28% of the patients when using the piezoelectric device (p = 0.032), with an intraoperative blood loss reduction of 18% (p = 0.156). Greater precision in bone cutting was reported, together with a reduction in the requirement to protect and incise adjacent soft tissues during piezoelectric osteotomies. There was a lower incidence of postoperative haematoma and swelling following piezo-osteotomy, and a significant reduction in postoperative nerve impairment (p = 0.002).

CONCLUSIONS

The ultrasonic surgical device guaranteed a clean bone cut, preserving the integrity of the adjacent soft tissues beneath the bone. Although the time required for a piezoelectric osteotomy was longer, the total operation time remained approximately the same. In conclusion, the device's lack of power appears to be a minor problem compared with the advantages, and an ultrasonic device could be considered a valuable instrument for paediatric craniofacial advancement.

Surgical care burden in orbito-temporal neurofibromatosis: Multiple procedures and surgical care duration analysis in 47 consecutive adult patients

Patients with orbito-temporal neurofibromatosis (OTNF) bear a heavy burden of surgical care. We studied 47 consecutive patients with OTNF from the French Neurofibromatosis 1 Referral Center cohort (n > 900), over a 15-year period to determine the clinical features most likely to predict repeat surgery and longer duration of surgical care. Forty-seven patients (5.2% of the NF1 patients' cohort) underwent 79 procedures with a 4.8 years average follow-up. Soft-tissue surgery had a high revision rate (19/45 patients), skeletal surgery did not (2/13 patients). Transosseous wire canthopexy and facial aesthetic unit remodeling were associated with stable outcome. Ptosis repair carried an unfavorable outcome, particularly in the presence of sphenoid dysplasia. Stable skeletal remodeling was achieved with polyethylene implants and/or cementoplasty. Multiple procedures were undertaken in 70% of patients and were predicted by the NF volume, canthopexy, skeletal dysplasia, or a Jackson's classification 2 and/or 3; but not by declining visual acuity. A classification based upon predictive risk of repeated procedures is proposed: Group 1: Isolated soft tissue infiltration not requiring levator palpebrae or canthal surgery; Group 2: Soft tissue involvement requiring ptosis repair or canthopexy, or NF great axis over 4.5 cm; Group 3: Presence of sphenoid dysplasia with pulsatile proptosis, regardless of visual acuity.

Decreased osteogenesis of adult mesenchymal stem cells by reactive oxygen species under cyclic stretch: a possible mechanism of age related osteoporosis

Age related defect of the osteogenic differentiation of mesenchymal stem cells (MSCs) plays a key role in osteoporosis. Mechanical loading is one of the most important physical stimuli for osteoblast differentiation. Here, we compared the osteogenic potential of MSCs from young and adult rats under three rounds of 2 h of cyclic stretch of 2.5% elongation at 1 Hz on 3 consecutive days. Cyclic stretch induced a significant osteogenic differentiation of MSCs from young rats, while a compromised osteogenesis in MSCs from the adult rats. Accordingly, there were much more reactive oxygen species (ROS) production in adult MSCs under cyclic stretch compared to young MSCs. Moreover, ROS scavenger N-acetylcysteine rescued the osteogenic differentiation of adult MSCs under cyclic stretch. Gene expression analysis revealed that superoxide dismutase 1 (SOD1) was significantly downregulated in those MSCs from adult rats. In summary, our data suggest that reduced SOD1 may result in excessive ROS production in adult MSCs under cyclic stretch, and thus manipulation of the MSCs from the adult donors with antioxidant would improve their osteogenic ability.

The GroEL protein of Porphyromonas gingivalis accelerates tumor growth by enhancing endothelial progenitor cell function and neovascularization

Porphyromonas gingivalis is a bacterial species that causes destruction of periodontal tissues. Additionally, previous evidence indicates that GroEL from P. gingivalis may possess biological activities involved in systemic inflammation, especially inflammation involved in the progression of periodontal diseases. The literature has established a relationship between periodontal disease and cancer. However, it is unclear whether P. gingivalis GroEL enhances tumor growth. Here, we investigated the effects of P. gingivalis GroEL on neovasculogenesis in C26 carcinoma cell-carrying BALB/c mice and chick eggs in vivo as well as its effect on human endothelial progenitor cells (EPC) in vitro. We found that GroEL treatment accelerated tumor growth (tumor volume and weight) and increased the mortality rate in C26 cell-carrying BALB/c mice. GroEL promoted neovasculogenesis in chicken embryonic allantois and increased the circulating EPC level in BALB/c mice. Furthermore, GroEL effectively stimulated EPC migration and tube formation and increased E-selectin expression, which is mediated by eNOS production and p38 mitogen-activated protein kinase activation. Additionally, GroEL may enhance resistance against paclitaxel-induced cell cytotoxicity and senescence in EPC. In conclusion, P. gingivalis GroEL may act as a potent virulence factor, contributing to the neovasculogenesis of tumor cells and resulting in accelerated tumor growth.

Significance of distraction osteogenesis of the craniomaxillofacial skeleton - a clinical review after 10 years of experience with the technique

INTRODUCTION

Distraction osteogenesis (DO) has been applied to the field of craniomaxillofacial surgery for more than two decades. Although relevant factors for successful distraction osteogenesis are well known there are ongoing controversies about indications and limitations of the method and there is still a lack of evidence based data. Since 2003 the principle of gradual lengthening has been applied to patients affected by different types of skeletal craniomaxillofacial deficiency within individualized treatment protocols at the Campus Virchow Klinikum - Charité Universitätsmedizin Berlin - by the same surgical team. The records of these patients were reviewed in order to assess the significance of the technique within the spectrum of a craniomaxillofacial department. During 10 years DO has been applied in 80 patients representing less than 1% of all patients that have been treated since 2003. Review of the protocols showed a heterogeneous group with a wide variance of parameters, the age ranging from 2½ to 51 years. Internal distraction devices were used in all cases and individually selected with respect to optimal stability during active distraction and consolidation phase. Although distraction related complications occurred the majority of procedures ended up with the favoured result and skeletal stability. However additional reconstructive surgery was required despite successful distraction in the majority of patients. Although DO has a low significance with respect to overall patient counts the method is a powerful tool within individual therapeutic concepts for the surgical correction of craniofacial anomalies that are characterized by skeletal deficiencies and should be seen as addendum to other surgical options. Predictable and stable results can be expected if the basic principles of the method are regarded.

Biomechanical analysis of a curvilinear distractor device for correcting mandibular symphyseal defects

PURPOSE

The local mechanical environment is a determinant of successful transport disc distraction osteogenesis. This study assessed the biomechanics of a curvilinear distractor device for correcting mandibular symphyseal defects.

MATERIALS AND METHODS

The finite element method was used to analyze an intact mandible, mandibular distractor bodies with different rail thicknesses (4, 6, 8, and 10 mm), and mandibular distractor bodies with rails and auxiliary lingual brackets.

RESULTS

Rail thickness was positively correlated with maximum von Mises stress in the distractor and negatively correlated with maximum displacement of the mandibular distractor bodies. The maximum von Mises stress occurred at the junction of the rails and fixed arms. It also exceeded the yield strength of the titanium material. Compared with the maximum displacement of the intact mandible, that of the mandibular distractor bodies was visibly increased.

CONCLUSION

An auxiliary lingual bracket can effectively decrease stress in such devices and displacement of mandibular distractor bodies. Rail fixation alone cannot achieve stability for distraction osteogenesis. Using an auxiliary lingual bracket effectively prevents distractor breakage and exposure.

The use of mandibular body distraction in hemifacial microsomia

Objective:

The goals of treatment for hemifacial microsomia include horizontalization of occlusal plane and acquisition of facial symmetry. Although horizontalization of occlusal plane can be easily achieved, facial symmetry, particularly in relation to mandibular contour, can be difficult to attain. Soft tissue is generally reconstructed to correct facial asymmetry, and no studies have described correction of facial asymmetry through skeletal reconstruction.

Case:

A 12-year-old girl presented with grade IIb right-sided hemifacial microsomia. She was treated using Nakajima's angle-variable internal distraction (NAVID) system for mandibular body distraction.

Results:

Following treatment, appropriate facial symmetry was achieved, and the patient was extremely satisfied with the results.

Conclusions:

Thus, we successfully treated the present patient by our novel method involving distraction osteogenesis. This method was effective and useful for several reasons including; the changes were not accompanied by postoperative tissue absorption, donor sites were not involved, and the treatment outcome could be reevaluated by adjusting distraction while the patient's appearance was being remodeled.

Effects of growth on maxillary distraction osteogenesis in cleft lip and palate

PURPOSE

The objective was to analyze the effects of growth on the long-term result of maxillary distraction osteogenesis (DO) in cleft lip and palate (CLP).

PATIENTS AND METHODS

Retrospective study of 24 CLP cases with long-term follow-up operated for maxillary DO using the Polley and Figueroa technique: 10 patients were distracted during growth, while 14 patients were operated after their growth spurt. Preoperative (T0), 6-12 months postoperative (T1), and ≥4 years postoperative (T2) cephalometric radiographs were evaluated. A classical cephalometric analysis was used to assess the treatment stability, and a Procrustes superimposition method was performed to assess local changes in the maxilla and the mandible.

RESULTS

At T0, the mean age was of 11.9 ± 1.4 years for growing patient, and 17.9 ± 3.5 years for patient treated after their growth spurt (P < 0.001). Between T0 and T1, a greater increase of the SNA was shown in growing patients (P = 0.036), but the relapse was more important between T1 and T2, with a significant decrease of the SNA (P = 0.002) and ANB (P = 0.032) compared to the patients treated after their growth spurt. Although not significant, growing patients showed greater rotations of their palatal plane and mandibular plane.

CONCLUSIONS

Maxillary DO in CLP does not correct the growth deficit inherent to the pathology. Overcorrection of at least 20% is advised during growth.

Perioperative incidents associated with internal maxillary distraction osteogenesis: a retrospective study of 20 patients

OBJECTIVE

This retrospective study aimed to assess the frequency and distribution of incidents encountered during the perioperative period of maxillary distraction with internal devices. The perioperative period was defined as the period between device placement and removal.

STUDY DESIGN

Records of 20 patients treated during 2004-2011 with internal maxillary distraction osteogenesis were examined. Incidents were registered in terms of severity and need of intervention.

RESULTS

Eighty percent of the patients experienced minor incidents, of which the most frequent were pain during activation and infections; 80% of these experienced ≥1 hard and soft tissue-related incidents, and 20% ≥1 device-related incidents. All incidents were solved with minimal or no intervention.

CONCLUSIONS

Maxillary distraction using internal devices is a safe treatment with only minor incidents in the perioperative period. Preoperative planning and good cooperation are essential for preventing postoperative incidents. Prophylactic antibiotic treatment during the distraction period may be indicated.

An oligodeoxynucleotide with promising modulation activity for the proliferation and activation of osteoblast

The paper explored the regulatory role of oligodeoxynucleotides (ODNs) with specific sequences in the proliferation and activation of osteoblast, using human osteoblast-like cell line MG 63 as the model. Through the administration of ODNs to MG 63 cells at a concentration of 1.0 μg/mL, ODN MT01 with positive effects on proliferation and activation of osteoblast was selected from 11 different ODNs by methyl thiazolyl tetrazolium (MTT) assay and alkaline phosphatase (ALP) activity measurement. To get a deeper insight into the molecular mechanism, effects of ODN MT01 treatment on the expression level of Sp7, runx-2, collagen-I, osteoprotegerin (OPG) and RANK ligand (RANKL) were determined using quantitative real time PCR and Western blotting. Remarkably, the mRNA and protein expression levels of Sp7, runx-2, collagen-I and OPG were improved after ODN MT01 treatment. Meanwhile, the protein expression level of RANKL was dramatically decreased. These results suggested that ODN MT01 had a significant impact in facilitating osteogenic proliferation and activation, and provided a direct evidence for the notion that single strand ODN could regulate the balance of bone formation and resorption, and thus was of great potential in the rebuilding of alveolar bone.

Cranial vault expansion by distraction osteogenesis

OBJECT

The object of this report is to present a conceptual and technical approach for expanding the cranial vault, by distraction osteogenesis, in patients with craniocephalic disproportion secondary to pancraniosynostosis and in patients with complex syndromic craniofaciosynostoses undergoing operations for aesthetic improvement.

METHODS

The clinical characteristics, techniques used, outcome and complications for all patients who underwent cranial vault expansions with distraction osteogenesis in Children's Hospital of Denver were reviewed.

RESULTS

Twenty-six cranial vault expansions were done in 24 patients. Nineteen patients presented with intracranial hypertension. Twelve of these had pancraniosynostosis and 8 had a syndromic diagnosis. Large segments of cranial bone were translated in a controlled manner for distances up to 30 mm. All but one of the patients with intracranial hypertension experienced complete resolution.

CONCLUSIONS

Cranial vault expansion by distraction osteogenesis has the great advantage, as the name implies, of generating new and vascularized autologous bone of the correct shape and in correct locations. The technique, although not simple and not risk free, is much less technically complicated and places patients at lower risk for the most serious complications than does single-stage vault expansion. Less soft tissue dissection and less devascularization of bone are required and there are no postoperative dead spaces. Distraction osteogenesis facilitates far greater vault expansions than do single-stage procedures and can be accomplished in any desired direction.

Maxillary-driven simultaneous maxillo-mandibular distraction for hemifacial microsomia

We treat hemifacial microsomia with a combination of surgery and orthodontic treatment during the growth period, resulting in early improvement in facial asymmetry and the induction of normal growth. We previously used gradual distraction of the mandibular ramus for Pruzansky's type II classification (Pruzansky, 1969). In type II cases, the maxilla should also be treated actively as, using this technique, improvement of the occlusal plane is difficult to achieve, resulting in a cross bite and difficulties in post-operative orthodontic treatment-especially in older patients. Morphologically, the mandibular angle region of the operative side is flat, and the angle of the mouth remains elevated. We performed mandibular-driven simultaneous maxillo-mandibular distraction while the occlusion was maintained using intermaxillary anchorage. However, mandibular-driven distraction tended to elongate the face because the mandible only elongated downwards and the mandibular ramus did not reach the glenoid. Furthermore, external distraction devices produce significant distress for patients until removal of the device and cause scars on the face. We developed a new internal distraction device with a variable angle and performed maxillary-driven simultaneous maxillo-mandibular distraction using this device. The result was morphologically satisfactory and solved the above problems. Because the patient was in the growth period, careful follow-up and induction to normal growth were important while the inferior growth of the affected side was monitored.