Long-Term Effects of Distraction Osteogenesis of the Mandible

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.

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 systematic review on the outcome of distraction osteogenesis in TMJ ankylosis

Introduction

TMJ ankylosis (TMJa) management by arthroplasty alone fails to address the deformity and the compromised airway. Distraction osteogenesis (DO) can offer a pragmatic solution to TMJa. The aim of the study was to generate evidence towards the role of DO in TMJa, evaluate its efficiency and develop an algorithm for use of DO in TMJa.

Material and methods

The research question was formulated using the PICOS statement for reporting guidelines in systematic reviews, where the efficiency of DO was evaluated in terms of mouth opening, correction of facial deformity and asymmetry, airway correction, and its long term effects.

Results

1130 articles reported DO as a treatment modality for TMJ ankylosis, of which 32 prospective studies, 16 retrospective and 2 RCTs were included in the study. DO was used for mandibular distraction in 45 studies and for simultaneous maxillamandibular distraction in only five studies. An algorithm for use of DO in TMJa was developed.

Conclusion

Although DO has proven its application in TMJ ankylosis cases, its best use is for correction of obstructive sleep apnoea. Relapse causing loss of posterior ramal height is a concern after transport DO. Prearthroplastic DO appears to best correct mandibular deformity. A maxillomandibular deformity requires simultaneous maxillomandibular distraction. However, a metanalysis is still awaited for effectiveness of DO in TMJ ankylosis.

Spatial Analysis of the Temporomandibular Joint and Condyle Following Mandibular Distraction in Robin Sequence

ABSTRACT

To comprehensively assess changes in temporomandibular joint and mandibular condyle morphology in Robin sequence (RS) patients undergoing mandibular distraction osteogenesis (MDO). A retrospective analysis of pediatric patients with RS and functional temporomandibular joints who underwent MDO by a single surgeon was performed. Preoperative and postoperative computed tomography (CT) scans were morphometrically analyzed three-dimensional in 3-matic and Mimics (Materialise). Comparative analysis was performed using Wilcoxon signed-rank tests. Fourteen RS patients were included (28 condyles, 56 CT scans), 78% male and 22% females. The mean age at surgery was 9.4 weeks (range 1.6-46.7 weeks). The average age at initial CT was 5.3 days (range 0-11 days). The mean time interval for CT scan before MDO and after hardware removal were 8.8 ± 6.4 days and 11.2 ± 25.8 days, respectively. Rotatory changes of the condyle revealed a significantly decreased horizontal angle following MDO (-7.55°, 95% confidence interval -11.13° to -3.41°; P < 0.001). Anteroposteriorly, the angle between condylar process and ramus (incline) increased significantly (14.14°, 95% confidence interval 10.71°-19.59°; P < 0.001). Intragroup analysis revealed no difference between left versus right condylar position measurements. The condyle itself increased in size and length and the intercondylion distance increased post-MDO. There were no complications and all patients achieved relief of airway obstruction without tracheostomy. Morphologic and positional changes of the mandibular condyle following MDO in RS patients parallel changes that occur during normal development in non-RS patients. As a result, MDO may facilitate normal condylar morphology and function in RS patients.

Pediatric Orthognathic Surgery: National Analysis of Perioperative Complications

BACKGROUND

Orthognathic surgery has traditionally been performed after skeletal maturity. Although these procedures are also being performed in children, the implications of earlier intervention and specific risk factors in this younger population remain unknown.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program Pediatric dataset was queried for orthognathic procedures performed in 2018. Complications, readmissions, and reoperations were analyzed with appropriate statistics.

RESULTS

Overall adverse event rate after orthognathic surgery in pediatric patients was 7.8% (n = 22 of 281), which were associated with having any comorbidity (P < 0.001), overall respiratory comorbidities (P = 0.004), structural pulmonary abnormality (P < 0.001), developmental delay (P = 0.035), structural central nervous system abnormality (P < 0.001), and neuromuscular disorder (P = 0.035). Most common complications were excessive bleeding (2.5%), surgical site infection (1.1%), and pneumonia (0.7%). Orthognathic surgery in children below 6 years of age is associated with significantly increased adverse events (P < 0.001), including surgical site infection (P < 0.001), pneumonia (P = 0.022), readmission (P < 0.001), and reoperation (P < 0.001). Le Fort I osteotomies (P < 0.001) and bilateral sagittal split osteotomies (P = 0.009) took significantly longer for older patients in the years of permanent dentition than younger patients in the years of deciduous dentition. Single- and double-jaw procedures in pediatric patients have similarly low adverse events (P all ≥0.130). Interestingly, bilateral sagittal split osteotomies performed before 13.5 years of age were associated with a higher risk of adverse events (P = 0.012), such that these younger patients were 7.1 times more likely to experience adverse events if their procedure was performed earlier.

CONCLUSIONS

Orthognathic surgery is relatively safe, but children in the years of deciduous dentition under 6 years of age have significantly increased risk of adverse events.

Device Malfunction Associated With Mandibular Distraction for Infants With Robin Sequence

INTRODUCTION

Mandibular distraction osteogenesis (MDO) effectively treats upper airway obstruction (UAO) in young patients with Robin sequence (RS). The most commonly used MDO devices have internal and external components that require manual activation. Although complications associated with MDO in infants with RS have been well documented, hardware/device malfunction has not been precisely described. The present study reports the authors' recent experiences with such problems, in an effort to shed light on these complications and identify potential steps to mitigate future related issues.

DESIGN

The authors reviewed a prospectively gathered database to identify all young children under the age of 3 years who underwent MDO using buried internal devices for UAO associated with grade 3 RS from March 2007 to September 2019. We specifically focused on complications attributable to the hardware itself.

RESULTS

Nineteen patients with 40 devices met inclusion criteria. The median age at MDO was 2.3 months (interquartile range 1.4-6.3 months). Intraoperative activation of all devices under direct vision resulted in satisfactory distraction. Four devices (10.5%) developed postoperative complications directly related to the device, including break down of component parts (N = 3) and failure to maintain distraction distance (N = 1). Two patients required surgical replacement of one device each, whereas the remaining complications occurred during the consolidation phase and did not require intervention.

CONCLUSIONS

This report documents a series of device/hardware malfunction in infants and young children undergoing MDO for severe UAO associated with RS. Despite rigorous testing and development, these devices may fail, resulting in patient morbidity.

Evaluation of Success of Transport Disc Distraction Osteogenesis and Costochondral Graft for Ramus Condyle Unit Reconstruction in Pediatric Temporomandibular Joint Ankylosis

PURPOSE

The costochondral graft (CCG) is considered the reference standard for pediatric temporomandibular joint reconstruction. It has the disadvantages of unpredictable growth, donor site morbidity, and the need for intermaxillary fixation. It has been reported that transport disk distraction osteogenesis (TDDO) can result in the formation of a neocondyle and disc. We performed a randomized trial to measure and compare clinically relevant outcomes of ramus-condyle unit (RCU) reconstruction using CCG and TDDO for pediatric temporomandibular joint ankylosis (TMJA).

MATERIALS AND METHODS

In the present randomized controlled trial (block randomization with a variable block size), pediatric patients with unilateral, nonrecurrent TMJA aged 3 to 16 years who had presented to our unit from December 2015 to June 2017 were enrolled. Instead of temporalis myofascial flap interposition, a buccal fat pad was used to fill the gap created by osteoarthrectomy. The primary outcome parameter was mouth opening. A mouth opening of at least 25 mm at the median follow-up point was considered success. The secondary outcome parameters were occlusion, laterotrusion, protrusion, reankylosis, neocondyle, chin deviation, facial asymmetry, midline shift, and neo-disc formation. Data were analyzed using the independent t test and rank sum test.

RESULTS

A total of 24 patients were enrolled in the CCG and TDDO groups (n = 12 in each group). Trauma (40.9%) was the most common etiology with a slight male preponderance (59.09%). The mean age was 10.32 ± 2.85 years. The average distraction achieved in the TDDO group was 10.42 mm. The median follow-up duration was 31.5 months (range, 24 to 39 months). The mean preoperative maximal incisal opening had improved from 8.5 ± 4.1 and 9.5 ± 7.1 mm in the CCG and TDDO groups preoperatively to 35.7 ± 2.7 and 34.4 ± 8.9 mm, respectively, at the median follow-up point (P < .005). RCU reconstruction with both modalities resulted in improvement in all the parameters; however, the intergroup comparison showed statistically non-significant differences. No reankylosis or open bite was found. The 3-hour delayed gadolinium-enhanced magnetic resonance imaging scan showed successful neo-disc formation.

CONCLUSIONS

Similar success can be achieved in RCU reconstruction using either CCG or TDDO for pediatric TMJA. Both techniques have some advantages and disadvantages. RCU reconstruction using CCG or TDDO results in formation of a neocondyle, maintenance of occlusion, and correction of facial asymmetry.

Mandibular distraction osteogenesis in the treatment of pediatric temporomandibular joint ankylosis with micrognathia and obstructive sleep apnea syndrome: A case report with 4-year follow-up

Temporomandibular joint (TMJ) ankylosis in pediatric patients is rare and may cause severe micrognathia and obstructive sleep apnea syndrome. The present study reports on the treatment and 4-year follow-up of a pediatric patient with early-onset bilateral TMJ ankylosis and severe secondary micrognathia, as well as obstructive sleep apnea syndrome. A typical ‘bird face’ appearance was noted with severe mandible retrognathism and a significant convex facial profile. The treatment of this patient involved TMJ ankylosis release with condylectomy and simultaneous bilateral mandibular distraction osteogenesis, which enabled the surgeons to simultaneously reconstruct the neocondyle and correct facial malformations. Following treatment, the micrognathia was corrected and the oropharyngeal airway was significantly expanded. However, the maximal incisal opening was limited. During the 4-year follow-up, no signs of mandible retraction were noted and mouth opening increased to 17 mm (passive) compared with the inability to open that was noted immediately following surgery. A certain degree of MIO shrinkage was identified in the patient. In such cases of TMJ ankylosis, early post-operative exercise, active post-operative physiotherapy and stringent follow-up are essential to prevent post-operative shrinkage and adhesions.

A History of Orthognathic Surgery in North America

This review highlights the contributions of American oral and maxillofacial surgeons to the field of orthognathic surgery. The present state of the art and science of orthognathic surgery is the harvest of yesterday's innovation and research. An improved understanding of the biological and surgical principles and the routine involvement of orthodontics have fueled widespread adoption of a coordinated approach to the treatment of dentofacial problems. Technologic advances in rigid internal fixation, virtual surgical planning with computer-aided manufacturing of occlusal splints and cutting guides, custom implants, and worldwide interest in the correction of dentofacial and craniofacial deformities have resulted in highly predictable, efficient, and safe treatment, which scarcely resembles the situation 70 years ago.

Neonatal Mandibular Distraction Does Not Increase Inpatient Complications

Objective:

The purpose of this study was to determine whether performing mandibular distraction osteogenesis (MDO) during the neonatal period increased inpatient complications as measured through health-care burden.

Materials and Methods:

This was a retrospective cohort study of the Kids’ Inpatient Database from 2000 to 2011. Infants receiving MDO prior to 12 months of age were included. The primary study predictor was distraction age, classified as either neonatal or non-neonatal. Secondary predictors were patient demographics, hospitalization characteristics, diagnoses, and procedures. The outcomes were the number of procedures performed, postoperative length of stay (pLOS), hospital charges, and the discharge transfer rate. Outcomes were compared between the primary predictors using χ2 and independent 2-sample t tests. Multiple linear and logistic regression models were created using clinically relevant predictors to assess the independent effect of neonatal age on each outcome.

Results:

The study sample contained 102 patients, of who 50 (49.0%) were distracted in the neonatal period. Neonatal MDO patients were more likely to have a cleft palate (86.0% vs 55.8%; P < .001) and present with feeding difficulties (38.0% vs 19.2%; P = .036) that were treated through total parenteral nutrition (26.0% vs 9.6%; P = .030) but otherwise did not have significantly different characteristics compared to non-neonatal patients. The multiple regression models confirmed that neonatal age did not influence any of the study outcomes, although other secondary predictors were found to influence the pLOS, hospital charges, and number of inpatient procedures.

Conclusions:

Neonatal MDO was not associated with increased complications. At experienced centers, neonatal status should not be considered a contraindication to treatment.

The Influence of the First-Stage DO Treatment of Palate Defect on Growth of Maxilla

To study the influence of distraction osteogenesis (DO) on the maxillary growth as first-stage treatment of palatal defect. The uniform palate defect experimental animal models (21 miniature pigs) were established surgically. Then animals were randomly divided into negative control group (A, n = 6), conventional surgery group (B, n = 6), and distraction osteogenesis group (C, n = 9) respectively. The group A underwent none treatment as control group, the group B were undergoing a conventional defect repair surgery, and the group C were undergoing a distraction osteogenesis treatment. Cone beam computed tomography examination was performed monthly to analyze the growth of maxilla for 6 months. One pig of group C was randomly sacrificed at 2, 4, and 8 weeks after the completion of DO and the tissue of distraction gap was stained with hematoxylin-eosin and Masson staining. At the end of 6th months, all pigs were sacrificed and tissues of the surgical area were stained as previous described. The palate defect was repaired by the distraction osteogenesis with the successful bone formation on the distraction gap. Group A and group C kept a similar growth rate, but that of group B was relatively slow. Distraction osteogenesis is efficient and successful for closing the defect of palate and there is no significant disturbance on the subsequent growth of the maxilla.