Mandibular osteotomy

WHAT IS MANDIBULAR OSTEOTOMY?

This is a surgical procedure that aims to mobilize the mandible to correct an anomaly in its position. The mandible may be too far forward (mandibular prognathism), too far behind (mandibular retrognathism), or deviated (right or left mandibular deviation).

The mandibular osteotomy corrects these various anomalies. This intervention is very often associated with orthodontic treatment.
A consultation between the orthodontist and the maxillofacial surgeon is essential in this case before surgery.

It also includes a study of models made from your dental casts, a study of your occlusion (relationship between the upper and lower teeth), a frontal and profile radiograph (cephalometric study), and finally a study of your temporomandibular joints (or TMJs).

OBJECTIVES OF THE SURGERY:

• Restoration of normal relationships between the teeth to allow you chewing your food in a correct way, thus preventing dental wear and gums receding and reducing pressure on your temporomandibular joints.
• Restoring normal relationships between the jaws and allowing to reduce the stress on your temporomandibular joints.
• Although this intervention has the main purpose of restoring and correcting the function, as mentioned above, it also brings an improvement of the overall harmony and aesthetics of the face, both in front and side view.

The procedure then corrects: a chin too far forward or too far back (in side view) or a chin deviated to the right or left (in front view)

TESTS PRIOR TO SURGERY:

Surgery is performed under general anesthesia, and requires 2-3 days of hospitalization.
If you wish to have a private room, please inform the anesthesiologist and the surgeon as soon as possible and complete the administrative formalities specific to hospitals for private rooms (those rooms must be booked in advance).

Preoperative tests consist of a blood test, an electrocardiogram and sometimes a chest X-ray.

Once the tests are done, you can make an appointment with the anesthesiologist: The anesthesiologist needs the results of these tests for the preoperative consultation.

THE ACTUAL SURGERY:

In addition to the general anesthesia, the surgeon performs local anesthesia in the mandible so that there is no pain.

An incision is made in the mouth, below the gum and well below the lower teeth (so totally invisible: the face's skin is never incised). The surgeon then proceeds precisely and rigorously to the osteotomy. The toothed part of the mandible is mobilized and exactly placed in the correct position. Titanium osteosynthesis plates are then fixed to hold the maxilla in the correct position and stabilize the whole. They are invisible (under the oral mucosa) and usually don't need to be removed.

During the surgical procedure, the upper and lower jaws are attached to each other with elastic chains allowing a perfect meshing of the teeth and a correct position of the maxilla (we speak of "intermaxillary fixation"). When you wake up, the jaws are not blocked by elastics except for exceptional cases, and in this case, you will be warned by the surgeon before the procedure. This fixation will be temporary.

The surgical procedure ends with absorbable suture, which should not be removed (it "dissolves" and disappears automatically).

In total, the surgery lasts 1h to 1h30 depending on the case.

POSTOPERATIVE RECOVERIES AND INSTRUCTIONS:

Directly after the surgery, you'll be taken to the recovery room, in which your parameters are strictly monitored (temperature, pressure, breathing, heart rate...like after any surgery).

You'll spend a few hours in the recovery room before returning to your room.

You'll have some ice (cold pack) applied on your cheeks to reduce the swelling.

You may feel swollen and that your lower lip's numb (due to the additional local anesthesia given by the surgeon just before the surgery).

The face (cheeks) gradually swells to reach the maximum 48 hours after surgery. So, don't worry if your face is getting more swollen, it's normal.

The swelling varies from a patient to another: some swell more than others. In addition, one side may be more swollen than the other.

In some cases, a hematoma may appear. All this is of course temporary. Applying ice on the cheeks immediately after the surgery and the semi-sitting position help to reduce the postoperative swelling.

A minor bleeding may occur in the operated areas but disappears quickly.

A temporary mouth opening limitation can also occur, but it is temporary. Physiotherapy sessions will be prescribed if necessary.

You will also be given all the medications you need in both the recovery and private room, intravenously.

These drugs are mainly anti-inflammatories, painkillers and antibiotics.

Postoperative instructions:

• You must absolutely not blow your nose during the 4 weeks following the procedure.
• Liquid and soft food (mixed) for 4 weeks and nothing hot during the 2 days after the surgery.
• Cautious mouthwashes diluted in water, starting from the day after the surgery and for 3 weeks after each meal.
• Ice on the cheeks (cold pack) during the 48 hours following the surgery.
• Do not smoke: smoking promotes infections, reduces wound healing and increases pain.
• Thoroughly brush your teeth and gums, starting from the next evening, with a very soft bristle manual toothbrush.
• The nursing staff will be available 24 hours a day during your hospitalization. They are perfectly aware of your case, so do not hesitate to call them as soon as necessary! It's their job!
• When leaving the hospital, the nurse will give you an appointment with the surgeon, who will see you for the follow-up a week then 3 after the surgery, then according to what he’ll decide.
• A consultation with the orthodontist usually takes place 1 month after the surgery, after approval of your surgeon. Orthodontic treatment usually lasts a few months after the surgery.

OPERATIVE RISKS AND COMPLICATIONS:

Any surgical procedure, even performed in the best conditions of competence and safety in accordance with the current scientific data and the regulation in force, carries risks of complication. Although very rare, the palatal distraction risks are:

Hemorrhagic complication:

Very rare during the surgical procedure, it can exceptionally require a transfusion of blood or blood derivatives.

Infectious complication:

Also very rare, it can occur in different ways:

• • Cheek abscess that sometimes requires surgical drain and possibly removing the osteosynthesis plates.

(I insist on the importance of not smoking after the surgery to reduce this risk!)

Nervous complication:

A partial or total loss of sensitivity (hypoesthesia or anesthesia) of the lower lip, chin, and lower incisors on the right or left side may occur when fixing implants. This is due to the lower dental nerve, which is responsible of the sensitivity of the lower lip and incisors, and which goes through the mandible.

These disorders generally disappear within a few weeks, or more rarely, a few months after surgery. A permanent loss of sensitivity is extremely rare. 

Rarely, an elongation of the lingual nerve which goes along the inner side of the mandible may occur and cause a loss of sensitivity of half the tongue. Disorders disappear within a few weeks to a few months. A permanent anesthesia is exceptional. The mobility of the tongue is never affected.

Bone or occlusal complications:

A delay of bone healing (pseudarthrosis) is exceptional in the maxillae, and the same goes for necrosis (some cases are described in the scientific literature).

If this ever happens, a new surgery is necessary to place new osteosynthesis plates or bone grafts.

A progressive deterioration of dental occlusion or recurrence can rarely occur and requires simple solutions to correct the gap (orthodontic treatment with elastic traction). A new surgical correction is exceptional.

Dental complications:

Very rarely, a root can be damaged during the procedure and require a root canal treatment.

Joint complications:

The occurrence or aggravation of a pre-existing dysfunction in the jaw joint (TMJ) may occur. For example, a crack and/or pain in the TMJ, or a mouth opening limitation can rarely occur. They are usually also temporary and will be treated by your surgeon, who's familiar with this kind of conditions.

In all cases, your surgeon operates and provides immediate postoperative follow-up, but also short, medium and long-term follow-up. He is trained to operate but also to manage all the possible and rare complications of surgery.

Follow every one of his postoperative advices, and know that if you have a question or face any problem, your surgeon will help you and knows how to perfectly handle the situation.

Upon admission to the hospital, the following documents will be required:

• ID card,
• Supplemental insurance documents, if you have one,
• Signed informed consent (available here),
• Admission documents specific to the institution.