Fig 1: Mid face Distraction used in cases where there is defeciency in midface as in crouzon's syndrome
Fig 2: Mandibular Ramal Distractor with Rigid External Pin
Fig 3: Mandibular Ramal Distractor with Flexible External Pin
Fig 4: Midface Distraction in progress in a patient with Crouzon's Syndrome
Facial disharmony can range in terms of form, size and shape of tooth and/ or jaws. Functional disharmony creates inability to chew, speak properly and can potentially interfere with normal breathing process. Aesthetic aspect includes loss of self-confidence and social isolation.
The treatment of children with facial deformities has advanced at a rapid pace over the past two decades. Keeping pace with recent global trends, our Hospital offers advances in medicine and technology to attain perfect results. Dr. Arul's expertise is at the forefront in the field of craniofacial anomaly surgery.
Distraction Osteogenesis is an innovative treatment option in cranio-maxillo-facial surgery. It is a means of stimulating production of new bone. In this procedure, the jaw bone is cut and the two arms of the distractor device are attached to the cut bone segments. After a few days the distraction procedure is started. The screw attached to the device is turned gradually (1 mm per day) which pushes the bones apart. New bone is formed in the resultant gap. After the desired jaw bone length is achieved, distraction is stopped. Once the new bone stabilizes, the distractor device is removed.
This cutting edge technology allows lengthening of the jaw without the formation of scars as the technique is approached from within the mouth.
Distraction is the magical technique by which we can achieve bone growth in childhood, early or even late adulthood. This technique is a boon to those who have bone growth retardation and to those who have lost some of their bone tissue to tumors or trauma. The versatility of this technique lies in the fact that corrections can be achieved more precisely even to the last millimeter.
A child’s lower jaw may sometimes be comparatively undersized than the upper jaw. This condition is termed as Micrognathia. The growth of muscles would also be simultaneously affected as the bony structure is smaller than normal. This condition could also be associated with various syndromes (Pierre-Robin’s Syndrome, Treacher Collin’s Syndrome etc). As the lower jaw is small, the tongue gets pushed backwards and tends to block the air passage. Distraction Osteogenesis is an effective treatment option to lengthen the jaw size. By this procedure the jaw can be brought to the normal size, without the necessity of bone grafting (bone harvested from hip bone to lengthen the jaw size).
In some individuals, there may be an imbalance between right and left sides of the face. This type of facial growth deformity characterized by facial asymmetry is called Hemifacial Microsomia. In this condition, the structures of one side of the face grow lesser than the other side. This results in asymmetry of the face. The affected side of the face appears disproportionately smaller than the other. The commonly affected structures of this deformity are the lower jaw, eyes, ears, facial nerve and the cheeks. The most significant defect is that of the jaws, which when corrected, minimizes the entire deformity and makes the face look almost symmetric.
The best and most advanced treatment technique of reconstructive jaw surgery for facial asymmetry is Distraction Osteogenesis. Our hospital remains the only center till date in this part of the world to offer simultaneous Distraction Osteogenesis (Distraction of both upper and lower jaw) for the correction of facial asymmetries and has successfully rehabilitated the maximum number of patients afflicted with facial disfigurements in the country.
Facial bone deficiency or Hypoplasia can be corrected by bone grown by distraction. The asymmetry of the face that occurs due to lack of growth on one side of the face can be set right by “Simultaneous Maxillary and Mandibular Distraction”
Advantages of Distraction osteogenesis
Distraction osteogenesis is a safe and precise technique to correct the bone defect. The amount of deformity as assessed by specialized X-rays can be corrected to millimeter precision.
Second surgery to harvest bone for bone grafting is avoided.
The results are stable and permanent with no relapse to the original size.
Distraction can be performed in three dimensions i.e. advancing, widening and increasing vertical height of the jaws.
Skin, muscles, nerves and vascular tissues are generated, not stretched, therefore along with the underlying bone deformity, the overlying skin and soft tissue defect is also corrected.
It can be used to simultaneously correct deformities of both upper and lower jaw.
It is the only procedure to increase the size of the jaw bones after the cessation of actual bone growth.
Uses of Distraction
Distraction osteogenesis can be used to lengthen the lower jaw. It also finds uses in the following:
Correcting anterior-posterior deformity of the jaws
To widen the jaws to correct teeth crowding
Increasing bone width and height of teeth bearing region of upper or lower jaw for dental implants
Previously failed bone graft sites
When available donor bone is insufficient
When patient is not an ideal candidate for bone grafting
Stages of Distraction
There are five stages of Distraction
Osteotomy- the surgery in which the bone is cut and the distractor device is fixed
Latency period- the time between the surgery and start of active distraction process
Distraction period – the period during which the distractor device is turned at a rate of 1 mm per day till the desired length is reached. The cut bone segments move apart.
Consolidation period- activation of the distractor is stopped and the bone formed in the gap is allowed to mature. The distractor device is removed at the end of this phase.
Remodelling phase – remodeling of bone occurs after the distractor device is removed.
Types of Distraction
Distraction can be classified in different ways.
Fig 1. Internal Midface Distractor-Plate type
Fig 2. Transport Distractor with Reconstruction Plate
Fig 3. Internal Midface Distractor-Mesh type
Fig 4: Internal Midface Distractor- Double Mesh type
Fig 5: Extra oral Mandibular Distractor
Fig 6:Midface distractor Kls Martin type-Frontal View
Fig 7:Midface distractor Kls Martin type-Lateral View
According to the site where it is used, it can be classified as mandibular (lower law), maxillary (upper jaw), alveolar (in teeth bearing region of the jaws), palatal (roof of the mouth) or craniofacial (skull).
Facial bones are unique. They are not straight, so they may be needed to be moved in more than one direction to achieve the desired results. According to the direction of bone movement, distraction may be univector (bone moved in one direction), bivector (bone moved in two directions) or multivector (bone moved in multiple directions).
According to the placement of the distractor, it is classified as Intraoral and Extraoral.
According to anchorage it may be fixed to teeth (teeth borne) or fixed to bone using plates or screws (bone borne).
According to the age for which it is designed, distractors can be either paediatric or adult.