Authors of section


Scott Bartlett, Michael Ehrenfeld, Gerson Mast, Adrian Sugar

Executive Editor

Ed Ellis III

General Editor

Daniel Buchbinder

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Surgically assisted rapid mandibular expansion

1. Introduction

The surgically assisted rapid transverse mandible expansion is a procedure designed for skeletal transverse widening of the mandible.

The widening is performed with either a tooth borne or a bone borne distraction device after a vertical osteotomy through the anterior mandible.

Orthognathic Surgery: Surgically assisted rapid mandibular expansion

2. Planning

For a detailed description of how to plan orthognathic surgery, please click here.

Planning of orthognathic surgery

3. Approach

For this procedure the transoral approach to the chin is used.

Planning of orthognathic surgery

4. Osteotomy

After intraoral exposure of the anterior mandible, a non-activated distraction device is adapted and placed on the bone surface. Care must be taken to position the activation port such that it is accessible and will not impinge on the surrounding soft tissues.

Holes for osteosynthesis screws are pre-drilled a safe distance from the tooth roots. The device is then removed and the osteotomy is performed.

Orthognathic Surgery: Surgically assisted rapid mandibular expansion

The osteotomy is usually performed between the roots of the central incisors down to the inferior border of the mandible. Below the level of the tooth roots, the osteotomy is made through both the buccal and lingual cortices. Above the level of the tooth roots the outer cortex is perforated with a small burr or with a piezoelectric device. A fine osteotome is then used to complete the interdental osteotomy.

Orthognathic Surgery: Surgically assisted rapid mandibular expansion

5. Expansion

Insertion of the device

After verification that the osteotomy is complete, the distractor is now reattached using the pre-drilled holes.

The expansion device is activated to assure that expansion occurs. The device is then deactivated (returned to starting position) prior to wound closure.

Orthognathic Surgery: Surgically assisted rapid mandibular expansion

After a suitable latency period, the mandible is distracted at a rate of 0.5 -1.0 mm per day.

During the distraction phase, a diastema will form between the two incisors (at the osteotomy site). Movement of the teeth into the regenerate will occur spontaneously unless the teeth are prevented from doing so by orthodontic appliances.

After reaching the desired expansion the device is left in place to retain the expansion and to allow for bone consolidation for at least 3 – 6 months before removal. Even after removal of the distraction device, it may be necessary to stabilize the expansion with an orthodontic appliance or an acrylic splint for an extended period of time.

Orthognathic Surgery: Surgically assisted rapid mandibular expansion

6. Aftercare following distraction osteogenesis

Apply ice packs (may be effective in a short term to minimize edema).

The sterile dressing placed over the skin incisions is maintained for a minimum of 48 hours. Thereafter routine wound care should be instituted around the activation rod.

Antibiotic prophylaxis is continued for 1-5 days depending on the nature, complexity, and duration of the surgical procedure.

Patients with intraoral wounds must be instructed in appropriate oral hygiene procedures. A small soft toothbrush with toothpaste should be used. Antiseptic rinses can be used in the early postoperative period. If a Waterpik is used, care should be taken not to direct the jet stream directly over intraoral incisions to prevent wound dehiscence in the early postoperative phase.

Early post-operative x-rays are obtained to verify correct device placement. Additional postoperative imaging is performed as needed.

Remove sutures from skin after approximately 5 days if nonresorbable sutures have been used.

Regular follow up examinations to monitor healing and the postoperative occlusion are required.

Avoid sun exposure and tanning to skin incisions for several months.