Reliability of Distraction Vector Transfer in Unilateral Vertical Distraction of the Mandibular Ramus

Evaluation of effect of single vector mandibular distraction for correction of postankylotic mandibular hypoplasia requiring multiplanar correction: A prospective case series

Introduction

Uniplanar devices have been criticized for being insufficient to correct complex mandibular deformities and associated problems of open bite and cross bite. The use of oblique vector to correct complex multiplanar deformities using uniplanar mandibular distraction devices is the uniqueness of the present case series.

Aim and Objective

The aim of the present case series is to describe the successful use of uniplanar mandibular distraction devices for the correction of complex multiplanar deformities.

Material and Method

The technique of callous molding was employed to overcome any open bite. A total of 40 mandibular distractors in 20 patients (mean age 13 ± 2.67 years) were placed on the mandible for correction of the facial deformity associated with the lower jaw(mandible) in vertical, horizontal and/or sagittal plane, secondary to temporomandibular joint ankylosis. The distraction was done before and after the gap arthroplasty in 15 and 5 patients, respectively. A latency period of 3-5 days was applied, and distraction was performed at a rate of 1 mm/day with the rhythm of 0.5 mm twice daily.

Results

The significant lengthening was observed in both mandibular height (Ar Go) (50.40 ± 1.52 mm from 38.80 ± 4.38mm, P = 0.006) as well as in mandibular corpus length (Go Pg) (79.40 ± 2.28 from 58.80 ± 4.09, P = 0.001). Statistically significant changes in mandibular dimensions, facial proportions, and soft tissue profile were seen, which was assessed with the help of COGS analysis done on lateral cephalogram taken preoperatively and postoperatively.

Conclusion

With intelligent vector planning and callus molding multiplanar complex deformities can be corrected by using semiburieduniplanar devices.

Unilateral mandibular hypoplasia in adult patients: distraction osteogenesis and conventional osteotomies in a standardized sequence

INTRODUCTION

This study analyzed the outcomes of nongrowing patients with unilateral mandibular hypoplasia treated according to a specific protocol, which combines distraction osteogenesis, orthodontic treatment, and conventional osteotomies.

MATERIALS AND METHODS

The patients treated were objectively evaluated. Patient's satisfaction was assessed by questionnaire. Surgical changes were analyzed using cephalometry and three-dimensional facial surface data before surgery (T0) and at long-term (T1) follow-up.

RESULTS

Four patients were included in this study. The normalization of facial proportion and a high increase in symmetry were evident. Residual defects were documented in the postoperative symmetry of the chin. In the questionnaire, all patients gave favorable responses to their facial changes; for most of the objective parameters, all patients improved.

CONCLUSIONS

A multistage treatment protocol for the correction of facial deformities in patients with unilateral mandibular hypoplasia is a valid procedure for skeletal and occlusal stability. An evident improvement of the facial appearance is also achieved.

Surgical Engineering in Cranio‐Maxillofacial Surgery: A Literature Review

A systematic review of the literature concerning surgical engineering in cranio‐maxillofacial surgery was performed. APubMed search yielded 1721 papers published between 1999 and 2011. Based on the inclusion/exclusion criteria, 1428 articles were excluded after review of titles and abstracts. Atotal of 292 articles were finally selected covering the following topics: finite element analysis (n = 18), computer‐assisted surgery (n = 111), rapid prototyping models (n = 41), preoperative training simulators (n = 4), surgical guides (n = 23), image‐guided navigation (n = 58), augmented reality (n = 2), video tracking (n = 1), distraction osteogenesis (n = 19), robotics (n = 8), and minimal invasive surgery (n = 7). The results show that surgical engineering plays a pivotal role in the development and improvement of cranio‐maxillofacial surgery. Some technologies, such as computer‐assisted surgery, image‐guided navigation, and three‐dimensional rapid prototyping models, have reached maturity and allow for multiple clinical applications, while augmented reality, robotics, and endoscopy still need to be improved.

Mandibular deformities: single-vector distraction techniques for a multivector problem

Single-vector distraction devices have been criticized for creating a malocclusion in an attempt to correct a three-dimensional mandibular deficiency, resulting in the evolution of a multiplanar device. Although there are indications for the use of a multiplanar device, a vast number of patients with mandibular hypoplasia can be effectively treated with a single-vector device, producing a normal occlusion and an aesthetic result while minimizing facial scarring and simplifying postoperative care. The purpose of this review was to describe surgical techniques whereby a single-vector device is effectively used in treating a multivector mandibular deficiency.A retrospective analysis of all patients who underwent mandibular distraction at the Children's Hospital of Philadelphia between 1996 and 2005 with a semiburied, uniplanar device was conducted. Charts, photographs, graphs, operative reports, computed tomography scans, and cephalometrograms were reviewed for those patients undergoing uniplanar mandibular distraction.Ten unilateral and 4 bilateral distractions were performed. In these 14 patients, causes included hemifacial microsomia, Treacher Collins syndrome, posttraumatic hypoplasia, and temporomandibular joint ankylosis with hypoplasia. The average device distraction was 29 mm (range, 18-34 mm). The average age at distraction was 8.4 years (range, 4-15 years). Surgical techniques for these patients will be described in detail. The single-vector, semiburied device can be effectively used to aesthetically correct a three-dimensional problem and to produce or maintain a class I occlusion while simplifying postoperative management and minimizing facial scarring.

Meta-analysis of mandibular distraction osteogenesis: clinical applications and functional outcomes

BACKGROUND

Mandibular distraction osteogenesis has been used effectively to treat syndromic craniofacial deformities. In recent years, its scope of application has widened to include treatment of airway obstruction in adults and children and nonsyndromic class II mandibular hypoplasia. So far, there has been no evidence-based review of mandibular distraction osteogenesis for mandibular lengthening.

METHODS

Two rounds of searches were performed by two independent assessors. The first-round PubMed search used the keywords "mandible" and "distraction osteogenesis." In the second-round search, the reference lists of the articles were retrieved. For both rounds, abstracts and then full articles were reviewed and selected on the basis of a set of inclusion and exclusion criteria.

RESULTS

The 178 retrieved articles yielded 1185 mandibular distraction osteogenesis patients: 539 received unilateral mandibular distraction osteogenesis and 646 received bilateral mandibular distraction osteogenesis. Mandibular distraction osteogenesis was reported to improve facial asymmetry and retrognathia (50.1 percent), correct the slanted lip commissure (24.7 percent), and improve or level the mandibular occlusal plane (11.1 percent) in unilateral asymmetry cases, whereas bilateral mandibular distraction osteogenesis was shown to be effective in preventing tracheostomies for 91.3 percent of neonates or infants with respiratory distress, and in relieving symptoms of obstructive sleep apnea for 97.0 percent of children and 100 percent of adult patients.

CONCLUSIONS

Mandibular distraction osteogenesis is effective in treating craniofacial deformities, but further clinical trials are required to assess the long-term stability and to compare the treatment with conventional treatment methods, especially in cases of obstructive sleep apnea or class II mandibular hypoplasia.