Technique and Procedure of Distraction Osteogenesis SurgeryDr Sanchaita Kohli
What is Distraction Osteogenesis?
Distraction osteogenesis is an advanced, innovative yet straightforward surgical technique that allows a permanent increase in the actual length or height of short or deformed bones using a metallic distractor device. This technique can be used to correct or reconstruct degenerated, resected or underdeveloped jawbones in the facial region, without the need for harvesting bone grafts from the body.
The technique of distraction osteogenesis is based on the tension-stress principle and involves putting gradual and continuous traction across bone segments that have been surgically separated. This constant stretching force develops a mechanical stimulation which induces biological responses and results in a tissue generation. We can think of it as slowly and constantly pulling apart two fractured bone segments to elongate the healing bone.
The use of the Distraction Osteogenesis technique in Oral and Maxillofacial Surgery has increased exponentially in the last two decades to correct distressing conditions like:
- Deficient maxilla or mid-face,
- Deficient or hypoplastic mandible (micrognathia),
- Elongating the lower jaw for correction of obstructive sleep apnea,
- Correction of asymmetrical jaws in syndromes like Hemifacial Microsomia,
- Jaw bone defects after surgical resection of jaw tumours and
- Deficient alveolar bone before placing dental implants.
At our center, we do the procedure using piezosurgery for bone cutting. It prevents the risk of injury to vital nerves and teeth during the surgery and makes the entire treatment experience safer and more comfortable for the patient. We also use distractor devices of premium and standardised quality to alleviate risk of infection and device failure.
Let us understand the procedure of distraction osteogenesis in detail.
Who needs Facial Distraction Osteogenesis?
Any deformity of the facial bones that requires a permanent and sizable increase in length or height is an indication for this procedure. Some examples are:
- Patients with repaired cleft palates almost always have small upper jaws requiring correction and distraction osteogenesis is the most stable way to provide this correction in such cases
- Patients with extremely small lower jaws may have trouble breathing (Obstructive Sleep Apnea) and require jaw lengthening by means of distraction osteogenesis
- People with Hemifacial Microsomia or other conditions causing an asymmetrical development of the jaws on the left and right side may require jaw lengthening on the shorter side by distraction osteogenesis
- Before placement of dental implants, often bone height may need to be increased by alveolar distraction osteogenesis
Jaw bone defects following surgical resection of jaw tumors can be reconstructed by means of distraction osteogenesis, especially when bone grafting is not an appropriate option.
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Benefits of Distraction Osteogenesis?
Facial jaw structure abnormalities can be generally treated by a combination of orthodontics and oral and maxillofacial surgery. The distraction osteogenesis technique offers new possibilities for treatment, such as upper jaw widening in the transverse direction and lengthening of the vertical mandibular ramus.
The procedure has also become a useful and better alternative treatment for conventional osteotomy for the lower jaw bone lengthening.
Let’s discuss some of its obvious benefits.
Distraction osteogenesis is far superior to other conventional procedures used to reconstruct/augment jawbones as:
- Augmentation is achieved using an individual’s bone, not any foreign or animal grafts.
- Unlike bone graft procedures, it does not require a donor site for bone harvesting elsewhere in the body.
- Results are much more stable than grafting procedures as it leads to lengthening of the soft tissue as well, greatly reducing the risk of relapse.
- Much larger corrections can be achieved with distraction osteogenesis that are not possible with other augmentation surgical techniques.
It is possible to adjust, control and correct the amount and direction of bone lengthening in the postoperative period as it is a slow and gradual process which can be modified based on the clinical effect visible after each traction cycle. This is in contrast to the sudden and final change produced by the conventional osteotomy and augmentation techniques during the surgery itself
How should you prepare for Distraction Osteogenesis?
Before every surgical procedure, there are a few things that you should keep in mind. While consulting your surgeon, you must discuss the precautions and requirements of the surgery in advance. Surgeons have to thoroughly plan the facial distraction osteogenesis procedure. Consult your surgeon on the following before the surgery:
- You must discuss your exact aesthetic and functional requirements with your surgeon.
- Dental relationships usually change after distraction osteogenesis. Orthodontic tooth alignment (braces) usually proceeds simultaneously with the surgery.
- Get acquainted with the functions of the metallic distractor device. It will be your companion for a few weeks.
- The entire treatment process involves two surgeries, one for device fixation and another for device removal after a few weeks.
- Inform your doctor of any medical illnesses, if you have.
- Avoid smoking for at least two weeks prior to the surgery.
Get oral prophylaxis (scaling) 1 week prior to surgery to improve oral hygiene and treatment outcome.
What is the Distraction Osteogenesis Procedure?
The surgical procedure of facial distraction osteogenesis involves giving a surgical cut in the undersized jaw bone (osteotomy) and fixing a distractor device across the cut using screws. Gradual activation of the device starts a few days after the surgery and results in bone separation at the osteotomy, leading to new bone formation in the gap created.
This process results in the generation of the bone and correction of the deformity. The activation continues for roughly 10-20 days after the surgery, depending on the extent of the deformity. After the desired clinical effect is achieved, the device is removed after a period of 6-12 weeks to allow for bone strengthening.
At RG Aesthetics, we use piezosurgery to cut the bone which prevents the risk of injury to vital nerves and teeth during surgery. This ensures that the entire treatment experience is safer and more comfortable for the patient. Also, we use premium quality and steam sterilized distractor devices to prevent any risk of infection.
The treatment planning done is meticulous, and jaw correction is planned down to the exact millimeter. At our center, the use of simulation surgery software during planning allows the patient to be an integral part of the treatment plan and accurately predict the surgical outcome.
The principles of Distraction Osteogenesis
In normal fracture healing, a soft callus starts to form, made up of new connective tissue, microscopic blood vessels, cartilage and soft spongy bone which allows the fracture site to heal. With this principle, this technique involves the manipulation of soft callus formation in the distraction chamber for structural lengthening of jaw bone.
Distraction rate in this method describes the distance in millimeters by which the bone is moved or stretched per day and distraction rhythm describes the frequency of device activation per day.
Distraction Osteogenesis comprises 4 sequential phases:
- Latency Phase: This refers to the time period required for the formation of the soft callus tissue. It can take 5-7 days, however it depends on the physiological and microvascular state of the bone generation over the distraction site. During this process, hypoxia is occurring at a cellular level over the osteotomized structure inducing angiogenic response; formation of new blood vessels from pre-existing ones and produce collagen synthesis. The latency period should be short enough to prevent hardening of the connective tissue and long enough for adequate soft callus formation. Clinically, this is the time delay between surgically fixing the distractor and the first activation of the distractor device after surgery.
- Distraction Phase: To achieve the required bone generation, the distraction device must be activated as per the suggested protocol by the oral and maxillofacial surgeon. The device can be activated by turning axial screws with a movement of 0.25- 0.5 mm per turn. It is very important to keep the distraction at an appropriate rate and frequency, thus the clinicians worldwide prefer to keep the frequency to 2-4 times of activation daily with the goal of 1.0-1.5 mm distraction rate every day. After three weeks of distraction, progressive calcification starts to form the bone.
- Consolidation Phase: This is the last phase of the distraction process. It entails a long period of immobilization where the stretched soft callus tissue is allowed to mature with the support of the device. The device keeps the callus in a stretched and stable position and prevents formation of a cartilaginous intermediate. The duration for the consolidation period is around 4-12 weeks with 8 weeks being the average. Doctors advise that this phase is kept twice as long as the activation period and the timing of consolidation depends on the location of the distraction site and rate of bone metabolism, among other factors.
- Remodeling Phase: Even after the distractor device is removed, the distraction regenerate or the new bone formed undergoes continuous maturation, strengthening and mineralisation for up to 1 year after the surgery. The new bone remodels to fuse with the original bone and acquires a shape to adapt to its functional requirements.
Where and by whom should you get Facial Distraction Osteogenesis?
Good oral and maxillofacial surgeons are trained to perform this type of surgery. Therefore, you must make sure to focus on the following before getting the surgery:
- The surgeon
- The center
- The techniques of surgery
If you are interested in getting the surgery, get a consultation, and ensure that you are satisfied with the surgeon, his/her techniques, equipment and the clinic. To get a long-lasting result and a safe surgery that minimizes risks of future infections, It is essential that your surgeon is an expert oral and maxillofacial surgeon.
Recovery after Distraction Osteogenesis?
After the surgery, with proper aftercare, you can have a safe recovery from the treatment. Here is what you should keep in mind:
- Distractor fixation is generally a simple and safe surgery, and only extensive cases may require hospitalization for 1-2 days after the surgery.
- The surgeon leaves a small part of the distractor device externally for regular activation for up to 12 weeks in some cases.
- The distractor device is activated after 3-7 days after surgery and goes on for approximately 10-20 days. You can easily do this at home.
- Patients might feel mild facial swelling and slight discomfort during the distractor device activation. This represents new bone formation.
- Solid foods and heavy exercise must be avoided for up to 8 weeks after the surgery to promote proper recovery.
- A period of jaw immobilisation may be required for a few weeks in cases with severe facial asymmetry.
- Regular saline rinses and cleaning of the device is advised to maintain wound hygiene and avoid any situation of infection.
- You may experience some slight transient numbness of the lip and nasal stuffiness in some cases, depending on the site of surgery.
- Device removal is performed as a second surgery after 6-12 weeks.
Risks involved in Distraction Osteogenesis?
While distraction osteogenesis procedure is a simple and safe technique to correct facial deformity, any surgery comes with a few potential risks and complications, which must be kept in mind during treatment.
- Lower jaw distraction osteogenesis may produce neck scars, which may hypertrophy depending on the individual’s healing tendency
- In the absence of good hygiene, wound infection may be seen around the distractor device
- Rarely, distractor devices may loosen and fail, especially if they are not well-handled or overused or if proper device selection is not done
- Improperly planned surgeries may result in faulty direction of bone growth
Therefore, you must get your surgery done by a well-qualified and expert surgeon who has experience in such surgeries.
Results of the procedure
After the distraction osteogenesis procedure, you would be able to achieve a much larger correction compared to other augmentation and repositioning surgical techniques.
It provides far more stable results for correction of facial asymmetry, jaw defects, or in patients with repaired cleft palates than bone grafting procedures as it leads to soft tissue lengthening as well, reducing the risk of relapse. It also makes reconstruction possible without requiring a donor site for bone harvesting elsewhere in the body, decreasing surgical morbidity.
Contact Dr. Sanchaita Kohli for further queries
If you have any facial deformity or any of the mentioned conditions requiring facial distraction osteogenesis, we are here to guide you and give you the best treatment.
We understand that you might be nervous about getting jaw surgery and getting metallic devices placed. We have covered all the necessary queries and doubts that you might have about the procedure; however, having further doubts is only natural.
Getting any kind of surgery is personal, and it can be tough to make a decision. This is why you must consult Dr. Sanchaita Kohli for any doubts and questions that may arise as you get to know the procedure in detail. Dr. Sanchaita Kohli is an expert Oral and Maxillofacial surgeon who operates at the prestigious cosmetic surgery setup of RG Aesthetics and has helped several patients with facial deformities.
Dr. Sanchaita Kohli
Oral and Maxillofacial Surgeon
Dr. Sanchaita Kohli is an Oral and Maxillofacial Surgeon with over 13 years of training and work experience at the country’s leading dental institute, Maulana Azad Institute of Dental Sciences, enabling her to plan and manage an extremely wide variety of craniofacial deformities, jaw diseases and facial trauma.