Comparison Between Internal and External Distractors in Osteogenesis

Comparative Study Between Internal and External Distraction Osteogenesis in Lower Face Asymmetry

Distraction osteogenesis is a powerful technique for creating new bone during significant lengthening of the mandible without the need for bone grafting and associated donor site morbidity.

The idea of distraction osteogenesis was largely abandoned by many until the 1950s. Ilizarov minimized complications by performing a corticotomy with minimal disruption of the surrounding blood supply and using a system of tension ring fixators to control the distraction in multiple planes. Through a series of experimental studies and clinical applications, Ilizarov established the foundation of distraction osteogenesis and its role in orthopedic management.

Applications in craniofacial surgery were first seen in 1973, when Synder et al applied the approach to mandibular lengthening in a canine animal model. Almost another 20 years passed before McCarthy and colleagues published, in 1992, the first report of mandibular lengthening in 4 children with congenital mandibular deficiency, 3 with hemifacial microsomia, and 1 with Nager syndrome. Thereafter, its role rapidly expanded to the midface and nearly all classic approaches to craniofacial reconstruction.

In general, mandibular distraction can be performed in the ramus for ramus lengthening, in the mandibular angle for downward and forward advancement, or in the mandibular body. Ramus or gonial angle distraction are mainly used to treat facial asymmetries as in hemifacial macrosomia.

Severe mandibular retrognathia can be classified as congenital or acquired. Congenital abnormalities that are associated with severe mandibular retrognathia or micrognathia include craniofacial syndromes such as hemifacial microsomia, Pierre-Robin syndrome, Treacher-Collins syndrome, and Nager syndrome. Adult patients with craniofacial syndromes may have undergone previous surgery at an earlier age, but unfavorable postsurgical growth or skeletal relapse may have occurred.

Severe mandibular retrognathia also can develop following maxillofacial trauma and mandibular fractures, which may have occurred in an adult or as a child Condylar fractures occurring at an early age can result in subsequent bony and/or fibrous temporomandibular joint ankylosis and/or deficient mandibular growth, also adult patients with complications from previous mandibular tumor resection and reconstruction can also present with acquired severe mandibular retrognathia that may require distraction osteogenesis as well.

Despite the advantages of extra-oral distraction devices in the hands of clinicians (application for very small children, simplicity of attachment, ease of manipulation, bidirectional and multidirectional dis- traction), patients are apprehensive about wearing bulky external appliances because of the social inconvenience and the potential of permanent facial scars, these disadvantages and limitations were the primary force driving the evolution of mandibular lengthening and widening toward the development of intra-oral devices.

However nowadays both internal and external distractors are used in a variety of indications in these cases each of the two types of distractor devices has its own advantages and disadvantages.

Aim of the work:

The aim of this study is to compare external and internal distraction devices for mandibular lengthening in terms of bone lengthening, patient comfort, and complications.

Study Overview

• Status: Unknown
• Conditions: Facial Asymmetry; Retrognathism; Micrognathia of Lower Jaw
• Intervention / Treatment: Device: Internal Osteogenesis distractor; Device: External Osteogenesis distractor

Detailed Description

The study will be conducted on 30 patients who are suffering mandibular problems either congenital acquired or post tumor mandibular resection that requires lengthening of the mandible, attending the outpatient clinic of Plastic Surgery Department in Ain Shams University Hospital & Assiut University Hospital.

Preoperative assessment:

• Informed consent will be obtained from all patients before their inclusion in the study.
• Photographs will be taken for the patient in lateral, antro-posterior and oblique positions preoperative.
• Lateral cephalometric radiographs or computed tomography (CT) or cone beam CT scans will be done for each patient pre-operatively.
• The decision to perform internal or external device will be based on preoperative and intraoperative considerations, such as anatomical bony characteristics affecting the possibility to place internal devices and patient cooperation.

Principles of the operation:

• anaesthesia: general anesthesia.
• Intraoperative consideration of internal versus external distractor is decided depending on the availability of bone stock.
• Osteotomy will be done according to each case individually making sure that it suits the vector of distraction required for each case.
• The approach for the external devices will be intraoral between the mental nerve anteriorly and gonial area posteriorly on both sides of the mandible.
• The approach for internal devices will be intraoral. While preserving the mandibular branch of the facial nerve.
• After 3-5 days of latency period for callus organization, gradual lengthening of the mandible will be performed at a rate of 0.5 mm twice a day for a total of 1 mm per day until achieving desired length.

Postoperative management and assessment:

• The patient will take broad spectrum and anaerobic antibiotics, anti-edematous, analgesic in addition to supportive treatment.
• After 3-5 days of latency period for callus organization according to patient age and condition, gradual lengthening of the mandible was performed at a rate of 0.5 mm twice a day for a total of 1 mm per day until achieving desired length.
• Following distraction phase there will be consolidation phase that will not be less than 8 weeks.
• Removing of internal or external distractor device and start retention phase if required with assistance of orthodontic appliances to avoid relapse.
• The patients will be evaluated with lateral cephalograms and head CT to assess the changes and amount of new bone formation following distraction.

• Study Type: Interventional
• Enrollment (Anticipated): 30
• Phase: Not Applicable

Contacts and Locations

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 3 years to 46 years (Child, Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

1. Males or females with congenital retrognathia or micrognathia.
2. Males and females between one month and 50 years.
3. Patients with acquired mandibular deformities as post traumatic (temporomandibular ankyloses), asymmetries, post-surgical as after mandibular tumor resection and irradiation.

Exclusion Criteria:

1. Patients with systemic illness as cardiac diseases, or mental disorders & hepatic patients (generally debilitating diseases).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

8

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: I-A Internal distraction; Internal osteogenesis distractor in congenital mandibular deformities in patients in growing age.	Device: Internal Osteogenesis distractor; Internal distraction osteogenesis in mandible
Active Comparator: I-A External distraction; External osteogenesis distractor in congenital mandibular deformities in patients in growing age.	Device: External Osteogenesis distractor; External distraction osteogenesis in mandible
Active Comparator: I-B Internal distraction; Internal osteogenesis distractor in congenital mandibular deformities in adult patients.	Device: Internal Osteogenesis distractor; Internal distraction osteogenesis in mandible
Active Comparator: I-B External distraction; External osteogenesis distractor in congenital mandibular deformities in adult patients.	Device: External Osteogenesis distractor; External distraction osteogenesis in mandible
Active Comparator: II-A Internal distraction; Internal osteogenesis distractor in acquired mandibular deformities in patients in growing age	Device: Internal Osteogenesis distractor; Internal distraction osteogenesis in mandible
Active Comparator: II-A External distraction; External osteogenesis distractor in acquired mandibular deformities in patients in growing age	Device: External Osteogenesis distractor; External distraction osteogenesis in mandible
Active Comparator: II-B Internal distraction; Internal osteogenesis distractor in acquired mandibular deformities in Adult patients.	Device: Internal Osteogenesis distractor; Internal distraction osteogenesis in mandible
Active Comparator: II-B External distraction; External osteogenesis distractor in acquired mandibular deformities in Adult patients.	Device: External Osteogenesis distractor; External distraction osteogenesis in mandible

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Rate of bone formation	6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Failure	Failure of distraction will be assessed by the amount of bone formed in mm and the target rate of bone lenghtening to be achieved... e.g.. if the target is to lengthen 20mm we consider failure if the bone lengthening is less than 20mm	1 month, 3months, 6months
Complications	infection will be assessed for discharge around the pins if fever is present after operation this will be considered as infection from surgery, post-operative scars wether the scar is depressed hypertrophic or keloid forming scar, loosening of the pins wehter they remained in place or otherwise they are loosened	1 week

Collaborators and Investigators

• Sponsor: Assiut University
• Investigators: Principal Investigator: Assem Kamel, MD, Assiut University; Study Chair: Osama Taha, MD, Assiut University; Study Chair: Awny Askalany, MD, Assiut University; Study Director: Ehab Ragab, M.Sc, Assiut University

Publications and helpful links

General Publications

• Rachmiel A, Levy M, Laufer D. Lengthening of the mandible by distraction osteogenesis: report of cases. J Oral Maxillofac Surg. 1995 Jul;53(7):838-46. doi: 10.1016/0278-2391(95)90346-1. No abstract available.
• Kaban LB, Padwa BL, Mulliken JB. Surgical correction of mandibular hypoplasia in hemifacial microsomia: the case for treatment in early childhood. J Oral Maxillofac Surg. 1998 May;56(5):628-38. doi: 10.1016/s0278-2391(98)90465-7. No abstract available.

Study record dates

Study Major Dates

• Study Start (Anticipated): August 1, 2018
• Primary Completion (Anticipated): May 1, 2020
• Study Completion (Anticipated): October 1, 2020

Study Registration Dates

• First Submitted: March 25, 2018
• First Submitted That Met QC Criteria: May 28, 2018
• First Posted (Actual): May 30, 2018

Study Record Updates

• Last Update Posted (Actual): May 30, 2018
• Last Update Submitted That Met QC Criteria: May 28, 2018
• Last Verified: May 1, 2018

More Information

Terms related to this study

• Keywords: distraction; osteogenesis; Lower face asymmetry
• Additional Relevant MeSH Terms: Congenital Abnormalities; Musculoskeletal Diseases; Stomatognathic Diseases; Pathological Conditions, Anatomical; Stomatognathic System Abnormalities; Jaw Abnormalities; Jaw Diseases; Maxillofacial Abnormalities; Craniofacial Abnormalities; Musculoskeletal Abnormalities; Mandibular Diseases; Retrognathia; Facial Asymmetry; Micrognathism
• Other Study ID Numbers: Distraction Osteogenesis

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Undecided

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No