Intraoral mandibular distraction osteogenesis: special attention to treatment planning

Monitoring of Home Respiratory Polygraphy During Mandibular Distraction Osteogenesis Succeeded by LeFort I Osteotomy in Adult Patients With Obstructive Sleep Apnea

BACKGROUND

Bilateral internal ramus distraction (BIRD) is now part of select protocols for treating obstructive sleep apnea (OSA). Introducing a home monitoring protocol offers a valuable alternative to overnight laboratory polysomnography (PSG).

PURPOSE

The purpose of this study was to evaluate and compare OSA parameters obtained via home respiratory polygraphy (HRP) and hospital PSG in a cohort of patients undergoing mandibular distraction for OSA management.

STUDY DESIGN, SETTING, SAMPLE

Hospital Universitario La Princesa (Madrid) researchers conducted a prospective cohort study with patients diagnosed with moderate (apnea-hypopnea index (AHI) = 15 to 30) to severe (AHI>30) OSA undergoing BIRD followed by LeFort maxillary osteotomy. Exclusion criteria were as follows: severe systemic diseases, central apneas, smoking, poor dental hygiene, or prior OSA interventions.

PREDICTOR VARIABLE

The predictor variable was PSG and HRP techniques.

MAIN OUTCOME VARIABLES

The main outcome variable comprises a collection of OSA parameters, including the AHI, oxygen desaturation index (ODI), and time spent below 90% oxygen saturation (T90). These data were measured both before and after distraction, as well as after 6 mm, 9 mm, and 12 mm of mandibular distraction.

COVARIATES

The covariates were age, sex, cardiovascular risk parameters, and the Epworth sleepiness scale.

ANALYSES

Pearson's correlation analyzed AHI, ODI, and T90 values from PSG and HRP. Wilcoxon Signed Rank-Sum Test compared 2 distraction stages, and the Friedman Test evaluated 3 stages (P < .05). Multiple regression analysis assessed if covariates were independent risk factors for postoperative persistent OSA.

RESULTS

The study included 32 patients (25% with moderate and 75% with severe OSA). Final AHI was 10.9 ± 8.9 (events/hour) with HRP, compared to 15.2 ± 13.4 with PSG (r = 0.7, P < .05). ODI was 9.0 ± 8.1 (des/h) with HRP and 8.7 ± 9.5 with PSG (r = 0.85, P < .05). T90 was 1.6 ± 2.2 with HRP and 1.3 ± 3.0 with PSG (r = 0.6, P < .05). Based on HRP data, AHI improved from D1 (34.0 ± 19.5) to D2 (20.8 ± 14.1) and D3 (12.5 ± 10.4) (P < .05). ODI decreased from D1 (26.1 ± 19.0) to D2 (16.0 ± 12.6) and D3 (9.4 ± 8.8) (P < .05). T90 reduced from D1 (8.2 ± 12.6) to D2 (4.1 ± 5.2) and D3 (1.9 ± 2.8) (P < .05). Multiple regression analysis of comorbidities produced nonsignificant results.

CONCLUSION AND RELEVANCE

Monitoring BIRD through HRP has demonstrated efficacy in yielding results that align with PSG.

Novel Use of an Internal Distractor for Metacarpal Lengthening

BACKGROUND

In patients who have had proximal digit amputation, metacarpal distraction osteogenesis is an option to improve digital length and function. One drawback is that traditional external distraction devices are large and cumbersome; the option of a low-profile internal device is therefore appealing. Internal distractors are commonly used in craniofacial reconstruction, but use in the hand has not been reported. We describe a case series of the novel use of an internal distractor in metacarpal lengthening.

METHODS

In this single-center case series, patients who underwent metacarpal distraction by the senior author using a uniplanar internal distractor were reviewed, and indications, outcomes, and complications were analyzed.

RESULTS

There were 5 cases in 4 patients (age range: 7-33 years). Indications were traumatic amputation in 4 cases and congenital hypoplasia in 1. All were successfully distracted, with a mean final length gain of 1.3 cm (range: 1.0-1.7 mm). Mean time from device placement to consolidation was 3.5 months. Complications included activation arm site infection in 2 cases, both occurring after the distraction period, necessitating device removal before full consolidation. In these cases, the device was removed after the distraction period and replaced with a Kirschner wire for stabilization through the consolidation period.

CONCLUSIONS

Metacarpal distraction was successfully achieved with an internal distraction device. Although infection was common, it occurred after the distraction period and did not preclude length gain. We feel that this low-profile device offers advantages over cumbersome external devices typically used for metacarpal lengthening.

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.

Two-Axis Continuous Distractor for Mandibular Reconstruction

The application of Distraction Osteogenesis (DO) techniques in the reconstruction of skeletal deficiencies is a relatively new topic in the fields of oral and maxillofacial surgeries. In many reconstruction applications, using DO is the preferred technique, as opposed to conventional reconstruction techniques, as there are more advantages and fewer side effects when it is used. The first generation of DO devices is made up of manual distractors that can apply an intermittent distraction force to the bone segment during the distraction process. Manual DO techniques have shown the functionality of the DO technique. Further research has recently been performed on the development of automatic devices for generating a controlled continuous force. However, the existing automatic techniques have limitations, and are yet to be used in reconstruction applications in humans. There is still a gap between the developed techniques and an ideal distractor to be used in mandibular reconstruction surgeries. In this research, a two-axis continuous distractor is proposed for use in mandibular reconstruction applications. The proposed distractor can generate two continuous distraction forces that can be applied to two independent distraction vectors. The proposed device can perform the standard distraction process using the predetermined distraction factors. The control system has a high positioning accuracy and resolution in controlling the position of the intra-oral end effectors while applying two continuous forces for moving the bone segment. The proposed two-axis continuous distractor meets the current requirements, and can be used as an ideal continuous DO device for different mandibular reconstruction applications.

Treacher Collins syndrome: Orthodontic treatment with mandibular distraction osteogenesis and orthognathic surgery

Interdisciplinary treatment for patients with Treacher Collins syndrome is challenging because of the rarity of the condition and the wide variety of phenotypic expression. A 23-year-old male was diagnosed with Treacher Collins syndrome with a history of severe obstructive sleep apnea. He presented with a Pruzansky-Kaban classification grade I mandible, skeletal type II pattern with a hyperdivergent mandibular plane, severe convex profile, and Class II malocclusion with a missing mandibular incisor. Improvement of facial esthetics was achieved by a combination of orthodontics, mandibular distraction osteogenesis, and 2-jaw maxillomandibular advancement surgery. Presurgical orthodontic treatment involved permanent tooth extraction to relieve severe crowding, and Class III mechanics were employed to increase overjet. Correction of mandibular hypoplasia by increasing ramal height and the mandibular length was done by intraoral mandibular distraction osteogenesis. Counterclockwise rotation of the mandibular plane angle and a Class III occlusion with negative overjet were achieved after mandibular distraction osteogenesis. A postdistraction posterior open bite was maintained with a biteplane during the consolidation period. Subsequently, 2-jaw orthognathic surgery was performed. LeFort I osteotomy was done for maxillary advancement to correct an anterior crossbite, eliminate canting, and reestablish occlusal contact at the mandibular occlusal plane. Bilateral sagittal split ramus osteotomy was done to correct the residual mandibular deviation. A genioplasty was also performed to improve chin projection. Postoperatively, the oropharyngeal airway was enlarged. The patient's facial profile and obstructive sleep apnea problem were improved as a result of advancement and counterclockwise rotation of the maxillomandibular complex.

A one-arm surgical trial of obstructive sleep apnea (OSA) patients before and 12 months after Bilateral Internal Ramus Distraction of the mandible (BIRD)

BACKGROUND

An innovative approach for the primary and definitive treatment of obstructive sleep apnea (OSA) in adult patients is presented: Bilateral Internal Ramus Distraction of the mandible (BIRD), which is a slow, progressive and more stable procedure to advance the mandibular bone. This study investigated whether this surgical approach is useful to cure OSA.

METHODS

Study design was of an interventional (surgical) one-arm trial of OSA patients assessed before and 12 months after BIRD. All patients were evaluated by pre- and post-operative polysomnography and three-dimensional scans. The amount of skeletal advancement, percentage of upper airway volume increase and postoperative value of mandibular occlusal plane were the predictor variables. Changes in the apnoea-hypopnoea index (AHI), oxygen desaturation index (ODI), and percentage of time with saturation under 90% (TC90) were the main outcome variables.

FINDINGS

Thirty-two subjects with a mean ± SD age of 41.9 ± 13.3 years and 87.5% male were included, and they were followed-up 32 ± 14.2 months. AHI was 47.9 ± 23.1 per hour before surgery and the Epworth Sleepiness Scale (ESS) was 13.4 ± 4.4. Postoperative AHI was 4.8 ± 5.6 per hour 12 months after surgery (P < 0.001), with 81.2% of the patients considered cured (AHI<5) and 18.8% suffering from a mild-to-moderate residual OSA. ESS decreased to 1.9 ± 1.8 at the end of the surgical treatment (P < 0.001). 3D changes revealed an upper airway volume increase of 188.4% ± 73.5% (P < 0.001).

INTERPRETATION

Lengthening the mandibular ramus by distraction osteogenesis to cure OSA appears to be more effective and safer when compared to other surgical protocols, especially in very severe cases with initial AHI>50/h. Titration of the mandibular advancement weekly using respiratory polygraphy allows better healing control and customization of the skeletal advancement, enhancing the aesthetic result.

Effects of Piezoelectric Surgery on Bone Regeneration Following Distraction Osteogenesis of Mandible

The aim of this study is to compare the bone healing in the distraction gap following the osteotomy performed with piezoelectric and conventional devices for the distraction osteogenesis in the rabbit mandibles. Twelve rabbits were randomly divided into 2 groups; 6 for piezoelectric device and 6 for rotary instruments. After 3 days of latency period, distraction was started at a rate of 1 mm per day for 10 days. All the animals were sacrificed after 4 weeks of consolidation phase for histological and histomorphological evaluation. Histological evaluation revealed thick trabecular bone formation in all of the specimens. Inflammation scores were chronic minimal. The mean percentages of the bone area in distraction gap are 62% in group P and 57% in group R. However, the difference between 2 groups was not statistically significant (P > 0.05). Our results revealed a slight increase in bone formation in the distraction gap in piezo-osteotomy groups histologically though not statistically supported. However, there is still a need for more histological studies with larger sample sizes evaluating the bone structure following piezo-osteotomies.

Unexpected events during mandibular distraction osteogenesis

Various unexpected events during mandibular distraction osteogenesis are described in 16 syndromic children with severely retrognathic or asymmetric lower jaws who were treated with unilateral or bilateral extraoral distraction. The mean total time with the distraction devices attached was 14 weeks (range 10-19). Although improvement in facial aesthetics and the desired occlusion was achieved in all but one case, there were unexpected events associated with mandibular distraction. These included pain not related to the operation, functional disturbance in movement of the jaw, dietary problems, weight loss, unfulfilled expectations of decannulation, temporary unilateral facial nerve palsy, and transient unilateral hypoaesthesia of the inferior alveolar nerve. Reoperation was required in 5 of the 16. In addition to these events, psychosocial problems within one family complicated the procedure. Patients and their families should be informed of the lesser-known aspects of distraction osteogenesis before the procedure is used.

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.

Condyle as the point of rotation for 3-D planning of distraction osteogenesis for hemifacial microsomia

AIM

The purpose of this study is to present an exact simulation method for mandibular rotational movement in distraction osteogenesis for hemifacial microsomia.

METHODS

Three-dimensional (3-D) surgery simulation software programmes (V-Works and V-Surgery; Cybermed, Seoul, Korea) were used, based on 3-D CT data in addition to the conventional data, which included facial photography, panoramic radiograph, cephalogram, and dental models. After measuring the mandibular deficiency (horizontal and vertical) from a 3-D model reconstructed using the software, the angulation of the distraction device to the mandibular border (posterior or inferior) was determined. The rotation axis in the V-Works simulation was defined as the line perpendicular to the plane made by condylion and the distraction vector location on the mandible. The mandible moves along the plane around this rotational axis during distraction. After the 3-D simulation with the software programme, mock surgery on a rapid prototyping model was performed. This planning method was applied to models of two hemifacial microsomia patients.

RESULTS

With this protocol, it was possible to simulate the rotational movement of the mandible on the axis passing through the condylar head of the unaffected side.

CONCLUSION

The sequential planning procedure presented in this paper is considered to be helpful in performing effective preoperative simulation of distraction osteogenesis for hemifacial microsomia.

Mandible Distraction Using Internal Device

For many years, surgeons have sought a method to treat severe facial deformities without using bone grafts and extensive surgery. Distraction osteogenesis offers this promise. The technique used in mandibular hypoplasia follows the basic principles proposed by Ilizarov which states that the device must be elongated 1 mm per day to create optimal bone production. Despite the widespread implementation of this recommendation to include the 1-mm/day separation, doubt still exists as to whether this is the optimal treatment regimen. Intraoral devices with percutaneous activator pins were used in 16 patients with hypoplastic mandibles. The results of distraction were documented by panorex and cephalogram of the mandible. The length of the ramus as well as multiple mandible dimensions and facial angles were measured. The panorex and cephalogram of the mandible were effective in demonstrating the significant increase in length of the mandible and ramus, as well as the entire mandible, but there was no correlation between the stretching obtained by the distraction device and that measured by the radiographic studies. The S-N-B angle was the only facial angle in which there is a statistically significant increase measured and this appeared to be related to a mandible rotation. It is concluded that the mandible distraction (using an intraoral device and an external activator pin) was effective in increasing the ramus length and both the panorex and the cephalogram were effective in demonstrating this morphologic change. There was no correlation between the clinical result and the radiographic studies demonstrating that the clinical judgment still has a significant role in controlling mandible distraction.

Internal Distraction Osteogenesis With a Unidirectional Device for Reconstruction of Mandibular Segmental Defects

PURPOSE

To present the authors' clinical experience with unidirectional internal distraction devices to reconstruct mandibular defects.

PATIENTS AND METHODS

Five patients have been treated with mandibular distraction osteogenesis to reconstruct different acquired segmental defects. These mandibular defects (35 to 80 mm in length) were reconstructed by means of internal distraction devices with a transcutaneous activator. All the patients underwent complete resection of the affected bone and immediate placement of the distraction device on the remaining mandible.

RESULTS

The results' analysis was based on clinical observation, postoperative radiographs, histopathologic findings and 3-dimensional computed tomographic scans. Successful distraction osteogenesis was achieved in 3 cases. In 1 case, extensive intraoral exposure of the device was observed, resulting in a failure of the procedure. One patient died of distant metastases 4 months after the resective surgery.

CONCLUSION

Because of the limited number of cases, this study is preliminary. However, considering the good experimental and clinical results, this new technique offers an alternative for patients with segmental mandibular defects in which, because of local or general reasons, a more aggressive procedure should be avoided.

Intraoral distraction osteogenesis to lengthen the ascending ramus. Experience with seven patients

Seven children with facial asymmetry, mean age 12 years (range 11-14.5) were treated by intraoral distraction osteogenesis to lengthen the hypoplastic ramus. We achieved a mean increase in length of the ramus of 13mm (range 10-16). In only one patient did we achieve a posterior open bite on the distraction side. All patients ended with a symmetrical chin. It was helpful to place an orthodontic bite block on the opposite side either preoperatively or postoperatively to cant the plane of occlusion. The duration of follow-up was too short to allow conclusions to be drawn about the future requirement for bimaxillary osteotomies.

Technical considerations in distraction osteogenesis

Five cases are presented to exemplify technical difficulties and complications which may be encountered when performing distraction osteogenesis in the facial skeleton. The procedure should be performed under close supervision by the surgical and orthodontic colleagues. Errors in the choice of vector may be managed by earlier removal of the distractor and subsequent traction on the previously osteotomized segments using orthodontic appliances and principles. Multiple distractors may be inserted in the same jaw and bimaxillary procedures are possible, increasing the likelihood of encountering technical difficulties. Detailed planning and close follow-up, with early recognition and active management of the complications, may be useful in ensuring a successful outcome of this versatile procedure.

Cephalometric evaluation of the craniofacial complex in patients treated with an intraoral distraction osteogenesis device: a preliminary report

The purpose of this pilot study was to evaluate cephalometrically the efficacy of an intraoral distraction osteogenesis device in treating patients with unilateral mandibular hypoplasia. Six patients with hemifacial microsomia underwent unilateral mandibular distraction. Posteroanterior and 45 degrees lateral oblique cephalograms were measured, and changes in maxillary width and height, occlusal height, ramus height, mandibular length, and chin position were quantified. Measurements were taken preoperatively and postoperatively at 7 time points (T1-T7) over 2 years. Calculations for statistical significance were done to T6 for all patients and through T7 for 4 patients. The means and variances were calculated for the 6 cephalometric variables for each time point. The mean differences between treatment and control were calculated as well as analysis of variance. Mean differences between specific time periods were measured by pairwise comparison with significance determined at the 0.05 level of confidence. Statistical analysis was used for descriptive purposes only. The cephalometric data suggest that the intraoral distractor is as capable of lengthening hypoplastic mandibles as the initial extroral appliances. The bone lengthening appears stable, with the distracted side of the mandible maintaining a growth rate similar to the normal side. Immediately after distraction, transient improvements were noted in maxillary height, ramal height, and maxillary width. All patients demonstrated an immediate improvement in chin position toward the skeletal midline; however, after T4, menton appeared to be moving away from the midline over time.

Distraction Osteogenesis of the Mandible With an Internal Bioresorbable Device

Lengthening of the mandible by distraction osteogenesis has been shown to be an effective treatment of hypoplastic mandibles. Use of an internal technique with a bioresorbable distraction device is presented. Mandibular lengthening was performed in seven patients aged 3.2 to 7 years. Six of the patients were diagnosed with craniofacial microsomia, anthe buccal aspect of the mandible, and distraction was started on the second postoperative day at the rate of d one was diagnosed with Nager syndrome. An internal bioresorbable device was placed along 1 mm/d and continued for 17 to 20 days. The distractor screw was maintained for retention for an additional 6 weeks and was then removed. All the patients showed clinical improvement. The postdistraction craniofacial computed tomography scans demonstrated elongation of the mandible with increase in the bony mass. The complications included device failure in one patient. The advantage of this method compared with the internal metal device is that it does not necessitate an additional procedure for device removal.

Pediatric Mandibular Distraction Osteogenesis: The Present and the Future

Pediatric mandibular distraction osteogenesis (MDO) has become a mainstay of treatment for patients with micrognathia and retrognathia. As craniofacial surgeons have gained experience with MDO, the technique has become a safe and durable means of mandibular lengthening that avoids the significant morbidity of conventional surgical treatments. The full impact of this technique has not yet been realized for pediatric patients. Although studies have confirmed durable reconstruction of mandibular length with MDO, the range of applications of this technique is currently limited. As innovative clinicians continue to apply MDO to pediatric clinical craniofacial problems not easily treated with conventional means, the field of MDO will continue to mature. This article discusses current uses and examples of potential future applications of pediatric MDO. The development of novel and creative applications of MDO will advance the management of complex craniofacial anomalies, taking the field of craniofacial surgery into the future.

Simultaneous orbital expansion and intraoral distraction osteogenesis of upper and lower jaws in a patient with hemifacial microsomia

BACKGROUND

Correction of a micro-orbit, caused by clinical anophthalmia is a very challenging task. In hemifacial microsomia a micro-orbit may be combined with hypoplasia of the malar and the ascending mandibular ramus.

MATERIAL

A 5-year-old patient with hemifacial microsomia is described. Hypoplasia of the malar bone and the tilted occlusal plane were corrected by means of intraoral distraction osteogenesis in the upper jaw following precise simulation surgery on a 3D-model. At the same time, the ascending mandibular ramus was lengthened with a second distraction device and a spherical tissue expander was inserted into the hypoplastic orbit.

RESULTS

The malar as well as upper and lower jaws were lengthened and positioned symmetrically. The orbital cavity was expanded to 79% of that of the healthy side. Following removal of the distraction devices, the expander was exchanged for a larger one and orbital expansion was continued until overcorrection of the orbit up to 118 percent was achieved.

CONCLUSION

Orbital expansion is a minimally invasive method of enlarging the volume of the eye socket three-dimensionally. Intraorally activated buried distraction devices enable "growth" of the jaws making bone transplants avoidable in many cases. By combining both methods, complex malformations can be corrected simultaneously in children.

Single-stage craniofacial distraction using resorbable devices

We report on the use of a new type of internal bone distraction devices designed for craniofacial applications. These resorbable devices allow a single operative procedure for device placement, eliminating the need for a second open operative procedure for hardware removal. We report on three models of resorbable devices. The midface orbital frontal device was used for midface and monoblock advancement. The mandibular adolescent device was used in older children and adolescents. In neonates and young children, the mandibular infant device was used. Twenty-one patients (9 female, 12 male) aged 6 days to 15 years (mean = 53 months) underwent bony expansion of the craniofacial skeleton over a 2-year period. A total of 39 devices were implanted: 32 in the mandible, 3 in the maxilla alone, and 4 in the maxilla and frontal bones. Expansion distances ranged from 15 to 30 mm. Expansion took place at 1 to 2 mm/d. Latency periods ranged from 48 to 72 hours. There were no device structural failures and no major complications.