Condylar replacement - Autogenous

When shortening of the mandibular ramus from condyle fracture results in malocclusion and or facial assymetry, the missing condyle should be replaced to restore ramus height, mandibular function, occlusion and facial symmetry.

Although many materials have been used for reconstruction of the condyle, the most common autogenous choice remains a costochondral graft. Its potential to remodel and grow makes it particularly attractive for reconstructions in growing patients.

Surgical approach is generally from a preauricular incision supplemented by a submandibular/Risdon approach.

For more details on the preauricular approach please click here.

For more details on the submandibular approach, please click here.

The incision will vary between men and women. In women it is important to try to place the incision in the sub-mammary crease. In men the positioning of the incision is less important and the primary consideration is to facilitate graft harvesting.

The important considerations are :

• Choice of sides: in general a costochondral graft for the left side is harvested from the right chest and vice versa because of the bone curvature required
• Incision of the periosteum over the rib to be harvested
• Retention of a rectangle of periosteum over the costochondral junction to reduce the risk of the bone becoming separated from the cartilage
• Raising of the periosteum with a periosteal elevator and a Doyen's rib raspatory. Great care should be taken when carrying this out beneath the cartilage as there is an increased risk of perforating the chest wall
• Ensuring the harvesting of a sufficient length of rib and cartilage
• Division of the cartilage with a knife
• Avoiding damage to the underlying periosteum and the pleura
• Division of the rib laterally with rib sheers
• Accurate repair of the periosteum with sutures
• If the periosteum and/or the pleura are damaged it is sometimes possible to repair them with simple sutures provided that the lungs continue to expand normally. If they do not do so, the insertion of an underwater sealed chest drain is necessary.

The costal part of the rib graft is shaped with a knife to approximate the condyle morphology.

2-3 mm of cartilage should be left on top of the rib.

The costal part of the rib is then positioned in the glenoid fossa under direct vision. Sometimes it is helpful to use a suture to hold it in position. It is important to ensure that it does not displace laterally.

Inferiorly it is fixed to the underlying ramus with at least three screws (generally 2.0 mm titanium screws). Plates may also be used as washers.

In case of recurrent ankylosis, alloplastic total joint replacement prostheses can be considered.

If MMF screws are used intraoperatively, they are usually removed at the conclusion of surgery. Arch bars may be maintained postoperatively for functional therapy.

Postoperative x-rays are taken within the first days after surgery.

It is imperative that the occlusal relationship and mandibular function be assessed early and on a regular basis. The patient is evaluated at 1 week to verify the occlusion and to assure adequate performance of functional rehabilitation exercises.

If a malocclusion is detected, the surgeon must ascertain its etiology (using the appropriate imaging technique). If the malocclusion is secondary to surgical edema or muscle splinting, training elastics will be beneficial. The lightest elastics possible are used for guidance, because active motion of the mandible is desirable. Patients should be shown how to place and remove the elastics using a hand mirror.

If the malocclusion is secondary to a bony problem due to incorrect bone alignment (mal reduction) or hardware failure or displacement, elastic training will be of no benefit. The patient must return to the operating room for revision surgery. A slight malocclusion can be corrected by orthodontics or dental adjustments with the help of a dentist.

The frequency of follow-up will largely be based on the findings of the 1 week appointment. Typically, if the patient is doing well at 1 week, they will not be seen for 2 more weeks. The necessity and frequency of future appointments will be based upon the findings from this appointment.

Postoperatively, patients will have to follow three basic instructions:

1. Diet:
The patient can consume liquids and semiliquids for the first couple of weeks and then advanced to more solid foods as tolerated and recommended by the surgeon.

2. Oral hygiene
Patients with extraoral approaches are not compromised in their routine oral hygiene measures and should continue with their daily schedule.
Patients with intraoral wounds must be instructed in appropriate oral hygiene procedures. The presence of the arch-bars and any elastics makes this a more difficult procedure than normal. A soft toothbrush (dipping in warm water makes it softer) should be used to clean the surfaces of the teeth and arch-bars. Any elastics are removed for oral hygiene procedures. Chlorhexidine oral rinses should be prescribed and used at least three times each day to help sanitize the mouth. For larger debris, a 1:1 mixture of hydrogen peroxide/chlorhexidine can be used. The bubbling action of the hydrogen peroxide helps remove debris. A Waterpik® or similar device is a very useful tool to help remove debris from the wires. If a Waterpik is used, care should be taken not to direct the jet stream directly over intraoral incisions as this may lead to wound dehiscence. The assistance of a dental hygienist may be helpful.

3. Physiotherapy
Patients are instructed in physical therapy maneuvers to restore mandibular excursions. This includes maximum jaw opening, right and left lateral excursions, and protrusive excursions of the mandible, as well as assistance from a physiotherapist if required. They should perform these exercises several times a day.