Double Jaw Surgery
What is a Bi-Maxillary Osteotomy?
Orthognathic or jaw surgery corrects conditions of the jaw and face related to structural issues, TMJ, sleep apnea, malocclusion or congenital problems such as cleft palates.
Most often corrective orthognathic surgery is performed on one jaw at a time, but when the upper and lower jaws are both operated on at the same time it is called double jaw surgery, two jaw surgery, or a bi-maxillary osteotomy.
This procedure may also involve a maxillomandibular advancement – moving the upper jaw (maxilla) and the lower jaw (mandible) forward.
What are “Degrees of Freedom” in Orthognathic Surgery?
When we talk about “degrees of freedom” in jaw surgery we are defining the directions in which the jaw can be moved into new positions.
For example, when we perform lower jaw surgery only, we use the upper jaw as a template for how the jaws fit together. In this case the only “degree of freedom” is dictated by the patient’s existing upper jaw orthodontic positioning.
Similarly with the upper jaw, the only degree of freedom is what the orthodontist has previously set up for the lower jaw. However, vertical facial height may also be altered which is an additional degree of freedom.
With double jaw, or bi-maxillary surgery, we have the most degrees of freedom and the more creative freedom to shape the face and move the jaws – giving the patient the best chance for a favourable outcome.
Case Study: Double Jaw Surgery Alleviates Sleep Apnea
A 55 year-old woman was suffering from a long history of sleep apnea – a potentially serious sleep disorder in which breathing repeatedly stops and starts while sleeping.
She had had multiple nasal surgeries and chin surgeries with another surgeon designed to improve her sleep apnea. These surgeries left her with a drooping chin, continued sleep apnea, and a poor shape to her face.
In addition she also suffered from a Class II malocclusion – a severe overbite wherein the upper teeth and jaw significantly overlap the lower jaw and teeth.
Prior to surgery Dr. Deschamps-Braly used a combination of old fashioned x-ray tracing along with virtual surgery planning on CT scans to ensure an accurate result. Intra-operative splints were then fashioned using 3D printers rather than making them by hand.
Dr. Deschamps-Braly performed bimaxillary surgery which involved advancing the maxilla 4mm forward and down 4mm, while bringing the lower jaw forward 7mm and moving the chin backwards 3mm as well as performing Chin Ptosis correction.
As a result of the surgery, the patient’s sleep apnea has now been nearly totally resolved. She reports that her daytime sleepiness has abated and that she loves her new appearance.