Authors of section

Authors

Scott Bartlett, Michael Ehrenfeld, Gerson Mast, Adrian Sugar

Executive Editor

Ed Ellis III

General Editor

Daniel Buchbinder

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Subapical (block) osteotomy

1. Introduction

Subapical osteotomies can be performed as isolated procedures or as part of total jaw osteotomies. They are indicated when the basal skeletal relationship is acceptable, and the malocclusion alveolar in origin. Subapical surgery can be performed in any region of the maxilla or mandible.

Subapical or block osteotomies are performed a safe distance (~5 mm) from the apices of the teeth, while maintaining the continuity of the mandible or maxilla.

Orthognathic Surgery: Subapical osteotomies

2. Planning

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

Planning of orthognathic surgery

3. Anterior maxillary osteotomy

The anterior maxillary osteotomy is typically performed from a limited vestibular approach. If a posterior repositioning of the anterior maxillary segment is desired, a preexisting dental gap or simultaneous extraction of teeth at the time of surgery is necessary. The osteotomies can be combined with either bone resections (ostectomies) or bone transplantation depending on the individual problem.

Orthognathic Surgery: Subapical osteotomies

After marking of the osteotomy lines on the bone, the horizontal and vertical osteotomies are performed. Care must be taken not to injure tooth roots.

Orthognathic Surgery: Subapical osteotomies

When a retro positioning of the segment is planned, a bone segment must be removed. Care must be taken not to injure the palatal mucosa, because it provides the blood supply to the anterior segment.

Orthognathic Surgery: Subapical osteotomies

After completion of the osteotomy and ostectomy, the anterior maxillary segment is positioned into a splint. Some surgeons prefer to have the patient in MMF while performing internal fixation, others rely on a splint attached to the dentition.

Osteosynthesis can be performed using small plates and screws if desired. Care should be taken not to injure the dental roots.

The soft tissues are closed, and the splint is usually left in place during the healing phase.

Orthognathic Surgery: Subapical osteotomies

4. Posterior maxillary osteotomy

The posterior maxillary osteotomy is performed to treat posterior maxillary alvelolar hyperplasia. The typical indication is for closure of an anterior open bite. The osteotomy is typically performed from a limited vestibular approach. If a superior repositioning of the posterior maxillary segment is desired an ostectomy has to be performed.

Orthognathic Surgery: Subapical osteotomies

The posterior maxillary osteotomy is performed to treat posterior maxillary alvelolar hyperplasia. The typical indication is for closure of an anterior open bite. The osteotomy is typically performed from a limited vestibular approach. If a superior repositioning of the posterior maxillary segment is desired an ostectomy has to be performed.

Orthognathic Surgery: Subapical osteotomies

After marking the osteotomy lines on the bone, the horizontal and vertical osteotomies are performed. Care must be taken not to injure tooth roots or palatal mucosa.

Orthognathic Surgery: Subapical osteotomies

In case of a superior repositioning an ostectomy of the lateral maxillary wall must be performed. A transantral osteotomy of the palatal bone is then performed through the lateral maxillary ostectomy window. Care must be taken not to injure the palatal mucosa because it provides the blood supply to the osteotomized segment.

Orthognathic Surgery: Subapical osteotomies

After completion of the osteotomy and ostectomy, the posterior maxillary segment is positioned into a splint. Some surgeons prefer to have the patient in MMF while performing internal fixation, while others rely on the splint.

Osteosynthesis can be performed using small plates and screws if desired. Care should be taken not to injure the dental roots.

The soft tissues are closed, and the splint is usually left in place during the healing phase .

Orthognathic Surgery: Subapical osteotomies

5. Anterior subapical mandibular osteotomy

The anterior subapical mandibular osteotomy is performed to reposition the anterior mandibular alvelolar process. The osteotomy is typically performed from an anterior vestibular sulcus approach. It can be used to position the anterior mandibular alveolar element in almost every dimension but is particularly indicated for vertical or tilting movements.

Orthognathic Surgery: Subapical osteotomies

After marking of the osteotomy lines on the bone, the horizontal and vertical osteotomies are performed. Care must be taken not to injure tooth roots or the lingual mucoperiosteum.

Orthognathic Surgery: Subapical osteotomies

Before any internal fixation is performed, the anterior mandibular segment is positioned into a splint. Some surgeons prefer to have the patient in MMF while performing internal fixation, while others rely on the splint

Osteosynthesis can be performed using small plates and screws if desired. Care should be taken not to injure the dental roots.

The gap is filled with autogenous bone, eg, from the iliac crest.

The soft tissues are closed, and the splint is usually left in place during the healing phase.

Orthognathic Surgery: Subapical osteotomies

6. Complete osteotomy of the alveolar ridge

Complete alveolar ridge osteotomies can be performed in both the mandible and maxilla. The goal is to reposition the complete alvelolar process. The osteotomy is typically performed from a vestibular approach. In the maxilla it is indicated for patients with a high alveolus/palate.

The osteotomies can be combined with either bone resections (ostectomies) or bone transplantation depending on the individual problem.

Orthognathic Surgery: Subapical osteotomies

7. Aftercare following orthognatic surgery with occlusal change

If MMF screws or Temporary Anchoring Devices (TADs) are used intraoperatively, they are removed at the end of surgery if not further needed for elastic traction. If a final splint was used, it may be fixed to the orthodontic devices (brackets) of the upper jaw to assure the planned occlusion and to serve as guidance for the neuromuscular adaption during functional training for about 2 weeks postoperatively.

To reduce swelling, the application of ice-packs or cooling devices during the early post-operative phase is advice. Intravenous steroids should also be continued for a short period postoperatively for the same purpose.

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

Especially in two-jaw surgery, the airway control is of major importance. An individual decision has to be taken if the patient can be extubated or should remain intubated until it is clear that safe airway can be established.

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

Regular follow up examinations to monitor healing and the postoperative occlusion are required. If an occlusal problem is present in the early postoperative phase, the surgeon must determine its etiology. If the malocclusion is secondary to surgical edema or muscle detachment/disorders, training elastics may be beneficial. The elastics are only used for guidance, because active motion of the mandible is desirable. Patients should be instructed how to place and remove the elastics using a hand mirror. If the malocclusion is secondary to a bone problem due to inadequate fragment positioning, displaced or failed hardware, or condylar displacement during surgery, elastic training will be of no benefit. The patient must be rescheduled for revision surgery.

At each appointment, the surgeon must evaluate the patient's ability to perform adequate oral hygiene and wound care and should provide additional instructions if necessary.

Postoperatively, patients will have to follow three basic instructions:

1. Diet
In orthognathic surgery the internal fixation devices usually do not allow for full functional load. A soft diet should be used up to 6 weeks, starting with liquids for the first 3-4 days. Elastics can be removed during eating.

2. Oral hygiene
Patients with intraoral wounds must be instructed in appropriate oral hygiene procedures. The presence of orthodontic appliances, the splint, and elastics makes this a more difficult task. A small soft toothbrush with toothpaste should be used.Any elastics are usually removed for oral hygiene procedures. Additionally, antiseptic rinses can be used in the early postoperative period. An oral irrigator (eg, Waterpik) is a very useful tool to help . 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.

3. Functional training/physiotherapy
The patient is instructed how to perform functional training (opening and excursive exercises) as soon as possible. The progress should be monitored by the surgeon. If available and needed, a physiotherapist can support the functional rehabilitation. An undisturbed mouth opening of minimum 35 mm interincisal jaw opening should be attained by 4 weeks postoperatively.

In case of undisturbed healing, the postoperative orthodontic treatment can usually start 2 to 6 weeks after surgery depending on the case.