Clinical controversies in oral and maxillofacial surgery: Part two. External versus internal distraction osteogenesis for the management of severe maxillary hypoplasia: external distraction

Patient-Specific Implants (PSI) in Maxillary Hypoplasia Secondary to Cleft Lip and Palate Deformity

Maxillary hypoplasia is often evident in cleft patients due to impaired growth and dense scarring from previous cleft surgeries. For these patients, treatment scenario has taken many turns over ages, evolved from orthognathic correction to distraction osteogenesis, with mixed prognosis and outcome depending on severity of the case and other several factors. We are reporting a case of 24-year-old female with maxillary hypoplasia secondary to bilateral cleft lip and palate with hypoplastic prolabium, who has been treated with two patient-specific implants in bilateral maxillary region for facial profile enhancement.

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.

Does Early Secondary Alveolar Bone Grafting Influence Need for Additional Maxillary Advancement Procedures in Cleft Lip and Palate?

OBJECTIVE

To determine if secondary alveolar bone grafting (SABG) timing in patients with cleft lip and palate (CLP) influences the future need for additional maxillary advancement procedures, particularly Le Fort I osteotomy with rigid external distraction (RED).

DESIGN

Retrospective cohort study. Groups were separated by SABG timing: early mixed dentition (ages 68 years) or late mixed dentition (ages 9-11 years). The criterion for RED was negative overjet ≥8 mm, and sufficient dental development for RED.

SETTING

Single tertiary care institution.

PATIENTS

Patients with CLP that underwent SABG from 2010 to 2015. Exclusion criteria included syndromic conditions, SABG surgery at age >12 years, current age <12 years, and <2 years follow-up. 104 patients were included.

MAIN OUTCOME MEASURES

The number of RED candidates and treated patients.

RESULTS

There was no statistical difference in the number of RED candidates (P  =  .0718) nor treated patients (P  =  .2716) based on SABG timing; stratification by laterality was also insignificant. Early SABG is associated with higher odds of being a RED candidate (pooled, unilateral, bilateral) and treated patient (pooled and unilateral); however, there were no statistically significant associations between SABG timing and the number of RED candidates and treated patients as determined by logistic regression models.

CONCLUSION

There is no statistically significant association between SABG timing and the odds of being a RED candidate or treated patient. Future prospective studies are recommended to assess the relationship between SABG timing and maxillary growth in patients with CLP.

Cleft Lip and Palate: LeFort I Distraction with Halo and Hybrid Internal Maxillary Distractors

Distraction osteogenesis is a viable treatment option for patients with a cleft associated with severe maxillary retrusion. A rigid external distraction device and a hybrid internal maxillary distractor have been used to advance the maxilla allowing for predictable and stable results. These techniques can be applied by itself or as an adjunct to traditional orthognathic procedures. The technical aspects are presented. These procedures tend to be simpler and demonstrate great stability compared to traditional surgical methods. The reasons for stability are discussed.

An Alternative Internal Le Fort I Distractor: Early Results With a New Trans-Nasal Device

PURPOSE

To report the early experience using a new internal trans-nasal Le Fort I distractor in patients with cleft lip and palate.

METHODS

Patients with cleft lip and palate and severe maxillary deficiency, who were treated with the trans-nasal Le Fort I distractor, were retrospectively reviewed. Cephalometric images were evaluated preoperatively and at least 6 months postoperatively. Speech outcomes were measured before and at least 6 months after surgery. Patient experience with the device was documented and complications were recorded.

RESULTS

Five male patients with bilateral cleft lip and palate (ages 11-19) underwent the maximum advancement allowed by the device (25 mm). Follow-up averaged 2 years. Average SNA changed from 75.5°preoperatively to 84.6°postoperatively. Average ANB angle changed from -2.8° to 7.4°, or a tendency to Class 2 overcorrection. There was an overall increase in upper anterior facial height by 7.5 mm. All patients achieved acceptable postoperative occlusions. Two patients with borderline velopharyngeal function preoperatively developed velopharyngeal insufficiency postoperatively that did not resolve 6 months postoperatively, necessitating further surgery. Families reported ease of turning with minimal discomfort reported by patients. All patients maintained normal mouth opening during and after the distraction phase. Two of the patients developed localized pin site infections after the distraction phase that were treated successfully with oral antibiotics.

CONCLUSION

The trans-nasal Le Fort I distractor can be an effective device to advance the deficient maxilla and is well tolerated by patients.

Skeletal stability in patients with clefts after large maxillary advancements using intraoral distraction

Maxillary hypoplasia is a common outcome in patients with cleft lip and palate after surgical and orthodontic interventions, and maxillary distraction osteogenesis has become a useful procedure for patients with extensive maxillary deformities. The aim of this study was to evaluate long term (two years) stability after maxillary advancement of more than 10mm by distraction osteogenesis in cleft patients using internal devices. We organised a retrospective study on 42 patients with cleft lip and palate using cephalometric analysis before and after maxillary distraction osteogenesis and evaluated them for 24 months. Postoperative measurements showed a marked advancement with an increase of 13.3mm and 10.8° in the length of the maxilla (Co-A) and SNA, respectively, including a shift from Angle class III to class I in dental relations. Follow-up observations showed preservation of maxillary length with a relapse of only 6.0 % (mean (SD) 0.8 (0.7) mm) and 10% relapse in SNA angle (mean (SD)1.1 (1.4) °) one year postoperatively and a negligible regression at the two years' follow up. This large-scale study shows stable results of skeletal advancement using distraction osteogenesis, indicating safe and reliable outcomes among patients with cleft lip and palate.

Initial Experience With a New Intraoral Midface Distraction Device

Maxillary hypoplasia that necessitates surgical advancement affects approximately 25% of patients born with cleft lip and palate. Syndromic conditions such as Crouzon may also be accompanied by significant maxillary hypoplasia. Severe maxillary hypoplasia can result in airway obstruction, malocclusion, proptosis, and facial disfigurement. For optimal stability, severe hypoplasia is best addressed with maxillary distraction osteogenesis. Twenty-two patients (15 boys, 7 girls, ages 6–16 years, mean age 10 years) with severe midface hypoplasia underwent midface distraction with new internal maxillary distraction (IMD) device at our institution. Total distraction distances ranged from 15 to 30 mm. There were no major complications, and all of them had improvement in functional and aesthetic parameters. There were 2 minor complications and 2 patients failed to distract the full distance because of converging vectors. Early maxillary distraction in patients with severe midface hypoplasia is a useful technique to provide interval correction of severe maxillary hypoplasia before skeletal maturity and definitive orthognathic surgery is contemplated, and it is a good tool to improve occlusion, aesthetics, and self-perception in younger patients.

Le fort I maxillary advancement using distraction osteogenesis

Treatment of maxillary hypoplasia has traditionally involved conventional Le Fort I osteotomies and advancement. Advancements of greater than 10 mm risk significant relapse. This risk is greater in the cleft lip and palate population, whose anatomy and soft tissue scarring from prior procedures contributes to instability of conventional maxillary advancement. Le Fort I advancement with distraction osteogenesis has emerged as viable, stable treatment modality correction of severe maxillary hypoplasia in cleft, syndromic, and noncleft patients. In this article, the authors provide a review of current data and recommendations concerning Le Fort I advancement with distraction osteogenesis. In addition, they outline their technique for treating severe maxillary hypoplasia with distraction osteogenesis using internal devices.

A novel technique to secure the Rigid External Distraction (RED) frame in a thin skull allowing sutural mid-face distraction

Distraction osteogenesis (DO) has revolutionised the treatment of mid-face hypoplasia in children, allowing advancement of the mid-face in excess of that achievable by traditional Le Fort III osteotomy. One method of performing DO is to use an externally applied frame, such as the Rigid External Distraction (RED) frame. However, at young ages the cranial bone is often too weak to support the frame, preventing its safe use. We present the case of a patient with Crouzon syndrome who required mid-face distraction at 4-months of age due to severe exorbitism, raised intracranial pressure and airway compromise. In order to allow safe application of an external distraction frame laminated bone grafts were secured to the cranium at the areas of frame pin insertion. We believe this to be the first reported case of the use of the patients own cranial bone to create laminated bone grafts and thicken the site of pin insertion. The method described adds to the armamentarium of the surgeon treating these patients who require placement of an external distraction frame for DO at a young age where the thickness of the cranial bone may otherwise prevent safe application.

Treatment of midfacial hypoplasia in syndromic and cleft lip and palate patients by means of a rigid external distractor (RED)

INTRODUCTION: Distraction Osteogenesis (DO) became an alternative for the treatment of severe craniofacial skeletal dysplasias. The rigid external distraction device (RED) is successfully used to advance the maxilla and all the maxillary-orbital-frontal complex (monobloc) in children, adolescents and adults. This approach provides predictable and stable results, and it can be applied alone or with craniofacial orthognathic surgical procedures. OBJECTIVE: In the present article, the technical aspects relevant to an adequate application of the RED will be described, including the planning, surgical and orthodontic procedures.

External craniofacial osteodistraction in complex craniosynostoses

PURPOSE

The use of distraction osteogenesis is the first option in the treatment of craniofacial hypoplasia. Both internal craniofacial distractor devices (ICDD) and external craniofacial distractor devices (ECDD) can improve visual and respiratory functions in patients with craniofacial synostosis significantly. They also improve the cosmetic outcome.

DISCUSSION

We reviewed the pertinent literature concerning the use of ECDD in complex craniostenosis. Surgical data as well as quality of life notes were analyzed and compared with those reported for ICDD.

CONCLUSION

The advantage of ECDD compared with ICDD is the easier application and postoperative management as compared with ICDD, with comparable results for extent and quality of distraction osteogenesis. The disadvantage is the quality of life which most authors report is worse if compared to ICDD during the distraction osteogenesis period.

Maxillary Movement in Distraction Osteogenesis Using Internal Devices in Cleft Palate Patients

Objective

The purpose of this cephalometric study was to compare the actual movement with the planned movement of the maxilla by using internal maxillary distraction in cleft lip and palate patients.

Patients

Twelve patients, including eight with unilateral and four with bilateral cleft lip and palate, underwent maxillary advancement with internal maxillary distractors.

Main Outcome Measures

Lateral cephalometric radiographs obtained preoperatively, predistraction, and postdistraction were used for analysis. The movement of the maxilla, angular change of the internal devices and rotation of the mandible were measured at each stage, and the planned vector of advancement predicted from the placement vector of the distractors was compared with the actual vector.

Results

Internal maxillary distractors were rotated in a clockwise direction during the distraction period. The angular change of the distractors was 7.7°. The amount of actual advancement at anterior nasal spine with distraction was 6.3 mm, which represented about 70% of the distance of activation of distraction. The actual advanced vector at anterior nasal spine was 9.7 smaller than the planned vector. The mandible underwent a clockwise rotation of 3.5°.

Conclusion

In the internal distraction technique, the maxilla was advanced inferiorly to the planned vector and with a slight clockwise rotation. These results are useful for surgical planning when using internal distractors.

Analysis of the biomechanical properties of the mandible after unilateral distraction osteogenesis

BACKGROUND

The purpose of this study was to establish biomechanical outcomes measures to evaluate how mandibular distraction osteogenesis affects the overall quality of bone healing. Strength and functional integrity of the regenerate were determined quantitatively after unilateral mandibular distraction osteogenesis in comparison with the contralateral mandible and a partially reduced fracture. The authors hypothesized that the breaking load, yield, and stiffness of mandibular distraction osteogenesis would be significantly reduced in comparison with both the contralateral mandible and a partially reduced fracture.

METHODS

Sprague-Dawley rats underwent mandibular distraction osteogenesis (n = 8) or a partially reduced fracture (n = 6). Distraction was performed using 4 days' latency and then 0.3 mm every 12 hours for 8 days (5.1 mm). Partially reduced fractures had gaps fixed postoperatively at 2.1 mm. Both groups underwent 4 weeks of consolidation. The contralateral mandibles were used as controls (n = 14). Mandibles were tension tested at 0.5 mm/second to failure, and then breaking load, yield, and stiffness were determined.

RESULTS

Mandibular distraction osteogenesis had significantly lower breaking load, yield, and stiffness than contralateral mandible, by 40, 30, and 60 percent, respectively. Breaking load was reduced in partially reduced mandibular fractures by 40 percent when compared with distraction osteogenesis.

CONCLUSIONS

Using a standard Ilizarov protocol, the biomechanical properties of breaking load, yield, and stiffness in mandibular distraction osteogenesis were significantly lower than those in contralateral mandibles. Surprisingly, the breaking load of mandibular distraction osteogenesis was significantly greater than that of partially reduced mandibular fracture. These verifiable metrics of regenerate integrity can be used to discern optimal outcomes of mandibular distraction osteogenesis, potentially enhancing the clinical applications of this powerful technique.

Regenerate healing outcomes in unilateral mandibular distraction osteogenesis using quantitative histomorphometry

BACKGROUND

The authors' goal was to ascertain regenerate bone-healing metrics using quantitative histomorphometry at a single consolidation period.

METHODS

Rats underwent either mandibular distraction osteogenesis (n = 7) or partially reduced fractures (n = 7); their contralateral mandibles were used as controls (n = 11). External fixators were secured and unilateral osteotomies performed, followed by either mandibular distraction osteogenesis (4 days' latency, then 0.3 mm every 12 hours for 8 days; 5.1 mm) or partially reduced fractures (fixed immediately postoperatively; 2.1 mm); both groups underwent 4 weeks of consolidation. After tissue processing, bone volume/tissue volume ratio, osteoid volume/tissue volume ratio, and osteocyte count per high-power field were analyzed by means of quantitative histomorphometry.

RESULTS

Contralateral mandibles had statistically greater bone volume/tissue volume ratio and osteocyte count per high-power field compared with both mandibular distraction osteogenesis and partially reduced fractures by almost 50 percent, whereas osteoid volume/tissue volume ratio was statistically greater in both mandibular distraction osteogenesis specimens and partially reduced fractures compared with contralateral mandibles. No statistical difference in bone volume/tissue volume ratio, osteoid volume/tissue volume ratio, or osteocyte count per high-power field was found between mandibular distraction osteogenesis specimens and partially reduced fractures.

CONCLUSIONS

The authors' findings demonstrate significantly decreased bone quantity and maturity in mandibular distraction osteogenesis specimens and partially reduced fractures compared with contralateral mandibles using the clinically analogous protocols. If these results are extrapolated clinically, treatment strategies may require modification to ensure reliable, predictable, and improved outcomes.