DISTRACTION OSTEOGENESIS
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Distraction osteogenesis = callostasis = stretching of a bone callus Gradual distraction of bones is accompanied by the soft tissues = less probability of relaps Method utilizing body’s own healing mechanism to generate new bone. Useful in reconstructing defects or discontinuity secondary to trauma, malignancy, etc. Less invasive, decreased morbidity www.indiandentalacademy.com
callostasis = stretching of a bone callus
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callostasis = stretching of a bone callus
Callotasis is a gradual stretching of the reparative callus that forms around bone segments interrupted by osteotomy or fracture. Clinically, callotasis consists of three sequential periods: 1) latency, 2) distraction, and 3) consolidation. Latency is the period from bone division to the onset of traction and is the time required for callus formation. The distraction period is the time when gradual traction is applied and new bone, or distraction regenerate, is formed. The consolidation period allows maturation and corticalization of the regenerate after traction forces are discontinued (Gantous et al., 1994; Murray & Fitch, 1996). www.indiandentalacademy.com
HISTORY
Codivilla 1905; First published description. • Sudden intense pull on the extremity under narcosis Abbott 1927; modified by step osteotomy. • Many complications; "left patients more crippled" Allen 1948; external device with screw • Allowed for daily activation, controlled elongation Iliazarov 1948; presented in US • Used the ring fixator Modified with DeBastiani; "Callostasis" Micheli and Miotti 1977 , first OMF reference • Used to lengthen mandible in sheep • Bony gap filled with collagenous fibres turning into lamellar bone www.indiandentalacademy.com
HISTORY • Distraction Osteogenesis was first used in orthopedic medicine in the early 1900's, but the current concepts evolved from the ideas of Dr. Gavriel Ilizarov, who practiced medicine in Kurgan, Siberia. Dr. Ilizarov, who had great understanding of the biophysiolgy of bone, developed techniques to move bone fragments in controlled vectors using a system of wires and fixed rings joined together with threaded rods and hinges. This technique allowed slow transport of bone segments without invasive surgery and was especially practical in the treatment of fractures in children and in lengthening of bones in the legs where there was a discrepancy between right and left bone lengths. www.indiandentalacademy.com
HISTORY
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DENTAL HISTORY ď Ž
The transfer of techniques involving D.O. in medicine to those used in dentistry was not an easy task. The reason being that the shape, size, location of bones is much different. The primary boost in the development of distraction osteogenesis techniques in the dental field came from the conceptualization and construction of miniature devices that could move small bone fragments in a controlled vector. In 1992, McCarthy, was the first to publish on the use of distraction osteogenesis to lengthen a human mandible. Dr. Martin Chin, a maxillofacial surgeon in San Francisco, was and still is a primary leader in this process. www.indiandentalacademy.com
DENTAL HISTORY
ď Ž
Distraction osteogenesis was initially used to treat defects of the oral and facial region in 1990. Since then, the surgical and technological advances made in the field of distraction osteogenesis have provided the oral and maxillofacial surgeons with a safe and predictable method to treat selected deformities of the oral and facial skeleton.
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DENTAL HISTORY
Distraction osteogenesis (DO) is a relatively new method of treatment for selected deformities and defects of the oral and facial skeleton. It was first used in 1903. Then, in the 1950’s the Russian orthopedic surgeon, Dr. Gabriel Ilizarov slowly perfected the surgical and postoperative management of distraction osteogenesis treatment to correct deformities and repair defects of the arms and legs. His work went mostly unnoticed until he presented to the Western Medical Society in the mid-1960’s. www.indiandentalacademy.com
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INDICATIONS
Mandibular Lengthening
Anterior-posterior deformity
Trauma reconstruction
Cancer reconstruction
Craniofacial syndrome
Mandibular Widening
Crowding with A-P deformity
Brodie Syndrome
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INDICATIONS
Asymmetry
Craniofacial Syndrome
Maxillary or mandibular alveolar distraction
Insufficient alveolar height and/or width
Previously failed bone graft sites
Insufficient soft tissue coverage
Insufficient dona bone available
Patient is not a candidate for a bone graft www.indiandentalacademy.com
Advantages of Distraction Osteogenesis
Little relapse Bigger movements possible Ability to mold the regenerate Out-patient surgery No need to extract teeth Generation of soft tissue Less likelihood of nerve injury Less likelihood of idiopathic condylar www.indiandentalacademy.com
resorption
Disadvantages of distraction osteogenesis
Technique sensitive surgery
Equipment sensitive surgery
Possible need of second surgery to remove
distraction devices
Patient compliance www.indiandentalacademy.com
Principles of Osteodistraction
Osteotomy in the area of deficiency
Application of external fixator
Initiation of the expansion forces
Maintenance of newly formed bone
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Principles of Osteodistraction
Latency period Common to all techniques • If not observed the new bone will have ¯ density • If too long; premature ossification 5-7 days according to Ilizarov, 14 d per DeBastiani Rate • Premature ossification if < 0.5 mm/d, fibrous > 2mm/d • 1 mm/d appears towww.indiandentalacademy.com be the optimal
Principles of Osteodistraction
Rhythm # of distraction events per day Best; continuos distraction, but not practical yet do 0.5 mm bid Frame design Must be compact enough to allow patient comfort The distracted bone must be maintained and protected from shearing forces if not fibrocartilage will form instead of new bone www.indiandentalacademy.com
Biology of Osteodistraction •
Bone formation via mesenchymal induction Unlike fracture healing •Karp et. al.(‘92) described the sequence of events •Initial fibrin clot at osteotomy site •Day 10 Collagen fibres (parallel to vector) in the gap. •Fine bony trabeculae seen at the periphery •Day 14 trabecular remodeling after distraction •Advance to middle to form osseous union •Day 28 bony continuity noted www.indiandentalacademy.com
Biology of Osteodistraction 7-fold increase in the blood supply to regenerate Hyper-trophy, -plasia of overlying muscle/skin Mild transient Wallerian degeneration of IAN Initial flattening of TMJ, remodeled Beneficial effects found in congenital deformities. www.indiandentalacademy.com
Devices
Can be performed for the mandible, maxilla, calvarium, orbit, midpalatal suture and maxillary or mandibular alveolus Distraction devices can be internal or external Internal devices can also be resorbable Distraction Osteogenesis for the Mandible Distraction Osteogenesis for the Maxilla
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Devices • • • • •
Mandibular - Pediatric - Linear Blue Device External Mandibular Vertical Distraction Midface
•Haas Palatal expander •Mandibular ramus distractor •Mandibular body distractor •RED craniofacial distractor •Mandibular bone transport ( U-Distractor) •Alveolar distractor www.indiandentalacademy.com
Mandibular
- Pediatric - Linear
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Blue Device
The Lorenz Advantage The Lorenz Mid-Face Distractor was designed by Doctors Martin Chin and Bryant Toth. These two surgeons have experienced several years of clinical success with this type of distractor. The device also permits use of both Rapid Distraction and standard distraction techniques.
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Blue Device
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Blue Device
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External Mandibular
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Vertical Distraction
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Midface
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Haas Palatal expander
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