Oral and maxillofacial procedures are usually performed in the operating room with the patient under nasoendotracheal general anaesthesia, and in a supine position with a specially designed plastic dish or towel roll for occipital head support. The trunk, head, and neck can be elevated slightly to reduce blood loss.

The surgical field is prepared by perioral swabbing with a soap solution for intraoral procedures, but oral irrigation with antiseptic solutions is not necessary. Surgical sites outside the mouth are prepared with povidone iodine solutions. Drapes are placed around the surgical site, or around the entire head and neck, depending on the size of the surgical field.

Oroendotracheal anaesthesia can be used for some procedures if nasoendotracheal intubation is impossible for anatomical or other reasons. Examples are reduction of zygomatic fractures, enucleation of jaw cysts, and tumour resections. Procedures that require intermaxillary fixation are not undertaken with oroendotracheal intubation unless the fixation can be applied after the patient has fully awakened from anaesthesia. Tracheostomy is used in situations requiring intermaxillary fixation as part of the surgical procedure if nasoendotracheal intubation is not possible.

The temporomandibular joint is of the ginglymoarthrodial–diarthrodial type, consisting of a bony condyle from the mandible meeting the glenoid fossa on the inferior surface of the zygomatic arch, anterior to the external auditory meatus. A meniscus of fibrocartilage lies between the condyle and fossa. This meniscus has an anterior attachment to the superior head of the lateral pterygoid muscle, a posterior attachment to bone, and lateral attachments to the joint capsule. The joint is thus divided into a superior space and an inferior space by the meniscus. The pterygomasseteric sling and the temporalis muscles are the principal elevators of the mandible, closing the mouth. The digastric muscle is a mandibular depressor, and the inferior head of the lateral pterygoid is a mandibular extruder: both of these muscles open the mouth. Mouth opening causes the condyle to rotate in the fossa and translate anteriorly out of the fossa over the bony articular eminence in front of the fossa.

Disorders that affect bone and soft connective tissues such as trauma, arthritis, neoplasia, and ankylosis can cause dysfunction of the temporomandibular joint. The most common dysfunction of the temporomandibular joint is the temporomandibular pain-dysfunction syndrome, which is related to dysfunction of the masticatory muscles. No surgical treatment is indicated. The dysfunction is best managed with occlusal splints, non-steroidal anti-inflammatory drugs, physical therapy, and behavioural modification. There are certain specific situations in which surgery of the temporomandibular joint is useful.

Surgical intervention should be considered in patients with chronic dislocation in which no psychological or neuromuscular factors are contributing; disabling ankylosis; internal derangement, when non-invasive techniques have failed to increase range of motion and relieve pain; degenerative arthritis,when non-invasive treatment has failed to resolve the symptoms; loss or absence of the mandibular condyle, because of congenital malformation, trauma, or surgical ablation; fractures of the mandibular condyle or condylar neck with dislocation or significant displacement; infections of the joint where drainage is necessary; and tumours of the joint.

The approach to the temporomandibular joint is by way of a 2.5 cm vertical incision in a skin fold immediately anterior to the ear pinna. The dissection is carried down sharply through the subcutaneous layer. The superficial temporal artery and vein are encountered deeper and are retracted posteriorly or tied and divided. The dissection is carried down to the temporal fascia superior to the zygomatic arch. Care is then taken to avoid the frontalis branch of the seventh cranial nerve as the incision is deepened along its entire length just anterior to the cartilage of the external auditory meatus. The skin and soft tissue flap are dissected forward along the zygomatic arch to the articular eminence. The joint capsule can then be seen.

The zygomatic arch and lateral pole of the condyle can be approached by two incisions, one along the lateral surface of the zygomatic arch, down to bone, and the second vertically through the lateral capsule on the lateral pole of the condyle. These two incisions allow access to the superior and inferior joint spaces, the meniscus, and the condyle. The incision along the zygomatic arch is useful for access to the articular eminence of the zygomatic arch when reduction of the eminence is needed for correction of chronic open lock or dislocation of the condyle.

Access to any portion of the inferior border of the mandible is gained by a skin incision located 2 cm inferior, and parallel, to the inferior border. The length of the incision is determined by the amount of access needed. Open reduction and internal fixation of a fracture normally require an incision 5 cm long. Removal of cystic or neoplastic disease of the mandible requires an incision of sufficient length to leave uninvolved tissue margins.

Dissection is carried sharply down to the platysma muscle, which is lifted and pierced bluntly with a haemostat. The platysma is incised for the full length of the overlying skin incision. The marginal mandibular branch of the facial nerve is avoided in this layer by testing for its position bluntly by snap compression of the platysma or by the use of a nerve stimulator. Facial nerve involvement is not a consideration in dissections in the midline to the mandibular symphysis because the nerve does not course through the soft tissues here.

The dissection deep to the platysma is continued until the inferior border of the mandible is encountered. The periosteum at the inferior border is incised along the length of the skin incision if direct access to the bone is desirable, such as in fracture reduction, sequestrectomy, and enucleation of cysts contained within the bone. Removal of neoplasms and cysts that have perforated the mandibular cortex requires blunt and sharp dissection around the lesion with adequate margins, rather than direct access to the bone. In the case of large, perforating, or malignant lesions, the mandible is resected with its overlying soft tissue. A radical neck dissection would be completed in continuity with the mandibular resection for malignant disease.

The wound is closed in layers, with approximation of the periosteum whenever practical. Closure of the platysma muscle permits accurate subcutaneous and skin closure. Drains are unnecessary except when resection of a large portion of muscle or bone makes point haemostasis incapable of controlling bleeding. In such a case, a suction drain to the tissue bed is used through a separate skin puncture.

The approach through skin, subcutaneous tissue, and the platysma muscle is made similarly to the approach to the inferior border of the mandible in the angle region. The incision is placed about 1 cm lower in the neck. A skin incision of 6 cm is sufficient. The submandibular gland capsule is visualized deep to the platysma muscle. Lymph nodes are usually attached and, in most instances, the facial artery and vein are encountered and divided after ligature.

Removal of the submandibular gland for obstructive, infectious, inflammatory, or neoplastic disease contained within the capsule is accomplished by circumferential blunt dissection. Dense fibrous adhesions must be divided without damaging the connective tissue capsule. The mylohyoid muscle forms the deep portion of the gland bed, and the lingual nerve is on the superficial surface of this muscle. This nerve, as it courses anteriorly, is deep, then superior to the submandibular gland duct. The duct is ligated and transected for gland removal, and the lingual nerve must be identified before this manoeuvre.

If malignancy or disease clearly extends beyond the capsule of the gland resection is performed with allowance for sufficient tissue margins. A radical neck dissection is part of the operation for malignancy, with removal of the gland as part of the composite resection.

Closure is carried out after careful haemostasis in the bed of the gland, eliminating the need for a drain. Closure of the platysma muscle layer makes subcutaneous and skin closure easy.

The mandible can be approached intraorally for open reduction and fixation of pure symphyseal fractures, removal of cysts and benign neoplasms when there is substantial inferior border, for open biopsy, for removal of impacted teeth, for genioplasty, and for the placement of implants.

The general principle of the intraoral open approach to the mandible in a dentulous patient is for the incision to be confined to the gingival sulcus between the marginal gingiva and the teeth. A mucoperiosteal flap is reflected, yielding good exposure of the mandible. The extent of the incision is determined by the amount of exposure needed to accomplish the procedure with adequate access, and allowing for the incision line to be over solid bone.

The incision in edentulous patients is through the attached gingiva along the crest of the alveolar ridge. A mucoperiosteal flap is reflected. Closure is accomplished by suturing the gingival edge of the flap back to the gingiva at the opposite side of the incision. Drains are unnecessary.

The approach to genioplasty and open reduction procedures for symphyseal fractures differs in that the incision is in the mandibular labial vestibule, allowing 1 cm of alveolar mucosa below the line of the attached gingiva. This more inferior incision allows more convenient access to the bony chin. The mental nerves, anterior extensions of the inferior alveolar sensory nerve to the lower lip, exit through the foramina inferior to the bicuspid teeth and then branch under the incised mucosa. Superficial dissection through the vestibular mucosa discloses these fine white filaments, which can then be isolated by sharp and blunt dissection and retracted for protection. The mentalis muscle is cut down to bone and is reflected off the bony chin. During closure, attachment of this muscle back to bone prevents a soft tissue chin deformity. The mucosa is then closed as the final layer. Drains are unnecessary.

The intraoral approach to the mandibular ramus for osteotomies is accomplished by a 5-cm incision starting posterolateral to the last molar tooth over the external oblique ridge and extending anteriorly lateral to the first and second molars. A 1-cm margin of gingival tissue is allowed between these teeth and the incision. A subperiosteal dissection then exposes the mandibular ramus, and is carried lateral to the ramus for vertical subcondylar osteotomies when a mandibular set-back is desired. The dissection is carried medial to the ramus and superior to the inferior alveolar nerve for a sagittal osteotomy if mandibular advancement is desired. Closure is accomplished at the mucosal level only. Drains are unnecessary.

Access to the maxilla for osteotomies, biopsy, sinus curettage, and resection of small benign lesions is obtained by an incision in the maxillary vestibule 1 cm superior to the mocogingival line and parallel to it. The length of the incision is governed by the extent of the maxilla to which access is desired. The incision is carried directly to bone, and the tissue is reflected superiorly as a mucogingival flap by application of a periosteal elevator. Care is taken to remain in the subperiosteal plane. If necessary, the flap can be reflected superiorly, the infraorbital nerve being identified and preserved. This is a sensory branch of the second division of the trigeminal nerve. It exits from the infraorbital foramen and supplies sensation to the soft tissue cheek, lateral portion of the nose, upper lip, and maxillary buccal gingiva.

The incision is 2 cm long over the canine fossa for access to the maxillary sinus. After dissection to bone, a trephine is used to create a 1-cm window through the anterior maxilla in the canine fossa. Access is immediately gained to the sinus for curettage, removal of foreign body, or resection of a mucocele. Before closure, the sinus is irrigated and a nasal antrostomy is created on the medial wall of the maxillary sinus into the nasal cavity at its floor. An antrostomy provides drainage of the sinus in the postoperative period. A Penrose drain is passed through this antrostomy and is kept in place for 2 days. The intraoral mucosal incision is closed in a running fashion with resorbable suture without a drain.

The incision extends from the maxillary buttress on one side across the anterior maxillary midline, to the opposite maxillary buttress for a total maxillary osteotomy (LeFort I). Bleeding at the time of the osteotomy can occur from the greater palatine vessels: this can be controlled by vascular clips. After completion of the osteotomy and its stabilization, the incision is closed with running absorbable sutures. Drains are unnecessary.

There are several alternative open approaches to the maxilla when osteotomies are confined to the anterior tooth-bearing segment. One approach uses three 2-cm vertical incisions placed in the alveolar mucosa above the two canine teeth and in the maxillary midline. Subperiosteal tunnelling allows this anterior surface of the anterior bony maxilla to be exposed. Osteotomy and repositioning of this segment can be performed while it remains attached to its blood supply through the palatal soft tissues. The other approach gains access to the same maxillary anterior segment from the palatal side through a transpalatal incision just posterior to the canine teeth. The maxillary anterior segment can then undergo osteotomy and repositioning while remaining attached to a blood supply through the labial soft tissue. These two approaches are unnecessary if the maxilla is cut in segments in conjunction with a LeFort I osteotomy. The segmental osteotomies can be performed from above in this instance. The incisions are still closed with running absorbable sutures and without drains.

Resection for a large benign neoplasm or for a malignant tumour in the maxilla might require partial maxillectomy. The entire half of the maxilla involved is usually removed for a malignant lesion. The resection can be more conservative if the lesion is judged to be benign. An effort is made to preserve the bony floor of the orbit. If this is impossible, preservation of the soft tissue orbital sling is essential to maintain the position of the globe. In rare patients with large maxillary malignancies, the globe is removed: an ophthalmic surgeon should assist. Preoperative evaluation by computed tomography helps to determine the degree of resection required.

If the globe is to be preserved, the skin incision begins in the infraorbital crease at the level of the orbital floor. It extends towards the midline and changes course inferiorly at the lateral border of the nose. The incision follows the lateral contour of the alar cartilage, turning under the nose close to the opening of the nostril. Upon reaching the midline of the philtrum of the lip it turns and divides the upper lip along the midline. Dissection is carried down to bone with a scalpel. The infraorbital nerve leaving the maxilla inferior to the orbital rim is preserved unless it is affected by the pathology.

The maxilla is exposed using a subperiosteal dissection unless the lesion has perforated through the maxillary bone. If this is the case, the lesion must be removed with adequate soft tissue margins. Complete subperiosteal dissection is, therefore, not always possible. Bleeding occurs predominantly from the greater palatine artery in the posterior maxilla. This artery is controlled with a vessel clip.

Closure of the extraoral tissue is accomplished in layers. Drains are unnecessary. When skin has been removed as part of the resection, a skin graft, pedicle flap, or free tissue transfer anastomosed to the facial vessel is needed for closure.

The intraoral wound is often left open. It can also be covered with a split-thickness skin graft from the thigh or buttock, which is sutured to the wound bed. The patient will have nasal speech; speech therapy, and help in, and lessons in swallowing are required. A prefabricated obturator can be placed after the resection, making speech and swallowing easier. These obturators are supported on any remaining teeth or on the maxillary alveolar ridge.

The oral and maxillofacial surgeon must know whether a skeletal deformity of the maxilla, mandible, or both is present. This requires physical examination and measurements from cephalometric radiographs. The lateral and frontal planes are both considered. Asymmetries are noted. Dental examination and dental casts allow analysis of the orthodontic movements required before surgery and ensure creation of a stable dental occlusion.

This operation is used to close an anterior open bite, correct a maxillary cant, or correct an anterior–posterior maxillary discrepancy. The maxilla is exposed using the intraoral open approach previously described. The nasal mucosa is dissected from the lateral and inferior walls of the nasal cavity and protected by insertion of a malleable retractor between it and the lateral bony wall of the nasal cavity. A sagittal saw is used with irrigation to create an osteotomy from the maxillary buttress to the pyriform aperture on both sides. Osteotomes with guarded blades are used to separate the maxilla from the medial antral wall. The vomer is separated from the nasal floor with a notched osteotome. The pteryomaxillary junction is separated with a curved osteotome to create a ‘green-stick’ type fracture. Care is taken not to drive the osteotome deep, since any bleeding may be hard to control. The maxillary down fracture is completed by gentle pressure on the anterior maxilla inferiorly. As the maxilla moves inferiorly, it remains attached to its blood supply through the soft palate and the greater palatine vessels. The greater palatine vessels are seen in the posterior of the wound, coursing from the ptyergoid plates to the maxilla. If intact, these vessels should be preserved. If bleeding occurs, these vessels are clipped.

The maxilla is mobilized for the planned movement of the facial skeleton by removing bony interferences with a rongeur or a burr. If a burr is used, irrigation is essential. The soft tissues are protected with retractors. Depending upon the treatment plan, bone can be removed to reposition the maxilla superiorly, anteriorly, or laterally, or to correct a cant. Interpositional grafts might be required to position the maxilla inferiorly. These can be obtained from any convenient source, such as iliac crest, rib, or the outer table of the cranium. The maxilla is stabilized with transosseous wires or bone plates with self-tapping screws. The usual points of fixation are the zygomatic buttresses posteriorly and the bone lateral to the pyriform aperture anteriorly. Intermaxillary fixation is applied unless rigid bone plates are used for stabilization.

The maxilla can be cut into segments from above if required. The osteotomies are done from above with a reciprocating saw, or a drill under continuous stream of irrigation with saline solution. Care is taken not to cut down through the palatal mucosa.

This is used to correct a prognathic mandible. Access is gained by the intraoral approach to the mandible previously described. The incision is confined to 5 cm over both external oblique ridges.

A subperiosteal dissection exposes the lateral surface of the mandibular ramus, including the sigmoid notch, condylar neck, posterior border, and angle. A guarded retractor (Bauer type) is inserted into the sigmoid notch to protect the masseteric artery. Another guarded retractor (Merrill type) is placed at the posterior border to protect the retromandibular tissues. A 135° oscillating saw with copious irrigation makes the cut from sigmoid notch to mandibular angle. The proximal segment is lifted laterally and is stripped of its pterygomasseteric muscle sling with a periosteal elevator. This movement allows the proximal segment to rest lateral to the ramus after the second side is cut; the mandible is then moved posteriorly to its planned position.

The osteotomy can also be performed through an open approach to the mandible in the ramus region. A straight-blade reciprocating saw is used with irrigation. The extraoral approach is not favoured since the same result can be obtained by the intraoral approach without a skin incision.

Intermaxillary fixation is maintained for 6 weeks after surgery. Fixation is usually accomplished by elastic bands connecting surgical orthodontic hooks, which are themselves placed on orthodontic appliances before surgery.

A significant, though rare complication of this osteotomy is damage to the inferior alveolar nerve, resulting in altered sensation to the ipsilateral tongue, alveolus, and lip. This is avoided by placing the osteotomy posterior to a bulge (the anti-lingula) on the lateral surface of the ramus. The anti-lingula marks the approximate location of the foramen on the surface of the medial ramus, where the inferior alveolar nerve enters the mandible. Placing the osteotomy posterior to this point reduces the risk of nerve injury. The risk is not eliminated because there is variation in normal anatomy.

This operation is usually used for advancement of the mandible to correct retrognathism, but can be used to correct prognathism and asymmetries. The intraoral open approach to the mandible is used. The incision is confined to approximately 5 cm in length over the external oblique ridges of the mandible.

A subperiosteal dissection is performed on the medial surface of the mandible from the base of the coronoid process to the posterior border. The subperiosteal pocket formed is kept superior to the entry of the inferior alveolar neurovascular bundle. A Lindemann burr in a straight hand piece, used with continuous saline irrigation, is used to cut through the medial mandibular cortex only, in a line from posterior border to the base of the coronoid. The neurovascular bundle is protected by retracting it inferior to the level of the bone cut with a Cushing periosteal elevator.

Subperiosteal dissection is undertaken next, on the lateral surface of the mandible from the base of the coronoid process to the inferior border, and anteriorly to the first molar. The Lindemann burr is used with continuous irrigation to cut through the lateral mandibular cortex from inferior border to superior border at the posterior edge of the second molar. The facial vessels are protected by inferior retraction with a channel retractor in the wound, and hooked under the inferior border of the mandible. The lateral and medial mandibular cuts are then connected up over the external oblique ridge of the mandible from posterior to anterior using a straight fissure burr under continuous saline irrigation. It is easier to make the oblique cut if holes are made in the superior border with the straight fissure burr, and then connected with the same burr.

The narrow and then the Obwegesser osteotomes are driven into the superior cortical cut with a mallet. The mandibular ramus begins to split in a sagittal direction. The inferior alveolar neurovascular bundle is identified in the osteotomy, and is dissected so that it will be with the tooth-bearing segment of the mandible. Sagittal spreaders can be used in place of the Obwegesser osteotomes to propagate the split.

Completion of the osteotomy through both mandibular rami allows advancement of the tooth-bearing portion of the mandible to the planned position, while the bony contact provided by the sagittal nature of the cuts allows healing to that portion of the ramus still left in articulation at the temporomandibular joint.

After advancement of the mandible fixation can be achieved using a superior border wire, an inferior border wire, or bicortical position screws. Lag screws are avoided because of the potential for them to compress the inferior alveolar nerve enclosed within the osteotomy site, and cause undesired rotation of the mandibular condyle in the temporomandibular joint. The lateral mandibular cortex of the proximal segment may break during the osteotomy. If it does, applying wire or screw fixation on the affected side may be impossible. In this instance, the intermaxillary fixation that would ordinarily be used for 6 weeks postoperatively for the wire fixation technique provides sufficient stability for healing. Patients treated with position screw bony fixation on both sides require limited intermaxillary fixation.

A severed inferior alveolar nerve and fracture of the lateral cortex of the proximal segment are the two most important complications. The latter is addressed in the preceding paragraph. The inferior alveolar nerve should be repaired using diopter loops and one to three 9–0 nylon sutures in the epineurium. Sensation to the lower lip has some chance of returning.

Surgical repositioning of the jaws sometimes causes a cosmetic defect of the chin. The defect can be a retrusion or an excessive prominence. Correction requires cephalometric radiographs which identify the chin contours resulting from a planned maxillo-mandibular movement.

Genioplasty is best performed on the bony chin itself, without implantation of synthetic material: synthetic chin implants can shift with time, resulting in deformities. The intraoral open approach to the mandibular symphysis is used. The incision is confined to the distance between the mental nerves, estimated from the mental nerve foramena seen on a panoramic radiograph. The mental nerves are dissected bilaterally, preserved, and protected by retractors.

The bony chin is reduced using a burr in a rotary instrument until the desired contour is obtained. Continuous irrigation of saline solution is began.

Augmentation is accomplished by cutting the bony chin from the mandible inferior to the root apices of the mandibular anterior teeth using an end-cutting reciprocating saw. A soft tissue pedicle to the genial muscles is preserved. The bony chin is then advanced to the desired position and is secured with stainless steel wire or position screws.

Augmentation can be achieved using free bone grafts to the bony chin, but the ease of working with the native chin makes this unnecessary for all but extremely large augmentations.

Closure includes suturing the mentalis muscle to the anterior cortex of the mandible. This precaution prevents a soft tissue deformity of the chin. The mucosa is closed with running absorbable suture.

The mental nerve is rarely severed in this procedure. If repair is required, one to three 9–0 nylon sutures are placed in the epineurium. The proximal stump of the mental nerve may need to be dissected from bone by enlarging the mental foramen with a rotary instrument and saline irrigation.

A genioplasty alone does not require intermaxillary fixation.

Many patients are unable to wear dental prostheses because of poor fit. Poor fit itself sometimes is the result of an anatomical problem, such as insufficient alveolar bony ridge upon which the denture rests, or soft-tissue contours over the alveolar ridge formed in a way as to be inconsistent with proper denture seating.

Insufficient alveolar bony ridge is treated either by bone graft augmentation or by implantation of titanium anchors. Anchors are commonly referred to as ‘dental implants’. Either procedure requires an intraoral open approach to the jaws, with the incision along the alveolar bony crest.

Bone graft augmentation provides a temporary increase in height and bulk of the alveolar ridge. Autogenous rib grafts, sometimes with autogenous iliac cancellous bone, are shaped to the desired contour and height of the alveolar ridge. These grafts are placed under the periosteum, the mucoperiosteal flaps being closed with non-absorbable sutures. Sutures are removed after 1 week. Some 50 to 75 per cent of the grafted bone is lost as remodelling occurs. The rate of bone loss is unpredictable. Implants offer prosthetic support, usually without bone grafts. Implants require placement in the alveolar bone in a position determined by the surgical and prosthodontic requirements. Co-ordination with a prosthodontist capable of constructing dental prostheses on implants is essential.

An alternative mandibular implant is the ‘staple’ bone plate. This is designed to be placed by the extraoral open approach to the inferior border of the mandibular symphysis, and has two transosseous pins that enter the mouth through the alveolar ridge as it is driven through holes drilled from below. Depending on the size selected, it has three to five screws which secure it to the inferior border of the mandible. The ends of the transosseous pins in the mouth are covered with temporary fixtures until the dental prosthesis is completed.

Implants are contraindicated in patients whose immune status would not stand the presence of foreign material. They are also contraindicated if the density of the bone is poor as detected by radiographs.

These are several classifications for the derangements of the temporomandibular joints, and the majority of treatments are non-surgical. However, when the patient is experiencing pain and restriction of mandibular motion, and when non-surgical means are unavailing, surgery may be part of the treatment plan. Although the position of the meniscus can be documented by arthrography, computer-aided tomography, or magnetic resonance imaging, the shape and size of the meniscus and the presence of intracapsular adhesions may also contribute to the derangement. The meniscus can be repositioned surgically through a preauricular incision. Repositioning of the meniscus is best accompanied by a high condylar shave to provide sufficient space within the joint for the meniscus to lie, and to allow the condyle to remodel to the new jaw mechanics. Small tears and perforations can be repaired and do not necessarily require the sacrifice of the meniscus. If the meniscus is considerably damaged it may have to be removed; consideration has to be given to its replacement. Previous experience with alloplastic materials has demonstrated that over the long term, most materials will fracture, displace, fragment, or cause a foreign body reaction. Some of these reactions are quite extensive, causing gross destruction of the mandibular condyle and the glenoid fossa to the extent that the middle cranial fossa is perforated. Treatment is then directed to removing the material and the granulation tissue aggressively. The joint is then restored with temporalis muscle flaps and rib graft to the condyle. Dermal grafts and ear cartilage grafts have also been used. Recent advances in small joint arthroscopy have allowed a better view of the internal mechanics of the joint; under certain circumstances, lysis and lavage and other surgical procedures can be beneficial. No long-term studies are available on arthroscopy.

Once entry has been gained, the meniscus, the glenoid fossa, and the meniscus are examined. Degenerative changes of the superior condyle surface are treated by removal of just this surface by an end-cutting reciprocating saw under saline injection. The meniscus is freed from its anterior and medial attachments to a sufficient degree to allow it to be positioned between the condyle and glenoid fossa. It is plicated to the periosteum over the lateral surface of the zygomatic arch using several non-absorbable sutures, such as 5–0 Tevdek.

Dissection of the meniscus attachments frequently causes bleeding from the severed attachment of the lateral pterygoid muscle. This is controlled by packing and pressure. Electrocoagulation in this location is not used unless the specific bleeding point can be seen easily and held with a haemostat. It is usually unnecessary to dissect the meniscus completely free medially to allow sufficient movement of it into the glenoid fossa.

The temporomandibular joint may be so diseased that it is unable to function: this may be due to tumour, previous surgery, or radiotherapy. The elements that preclude proper function are replaced. Although many companies have marketed temporomandibular joint replacements, none is universally successful. It is therefore preferable to use autogenous materials. One example is a costochondral graft for replacement of a diseased mandibular condyle. Another example is a free iliac bone graft surgically shaped to resemble the portion of the condyle and the mandibular ramus to be replaced. The rib and iliac grafts are harvested from the side of the body opposite to the temporomandibular joint being reconstructed. The natural curve of the rib or iliac bone approximates the portion of the mandible being replaced.

The surgical approach to the temporomandibular joint for reconstruction combines the open preauricular approach to the joint and the submandibular approach to the inferior border of the mandible, in the angle region. These approaches have been described above. The combination of these approaches provides access to the joint and convenient access to the lateral surface of the mandible where internal fixation devices are placed to hold the graft in place.

The part of the graft replacing the mandibular condyle must be positioned in the glenoid fossa of the temporal bone. Direct vision of this manoeuvre is recommended: failure to see well enough results in a dysfunctional reconstruction.

The choices for internal fixation of the graft to the mandible include wires, position screws, lag screws, and various reconstruction metal plates. Although choice depends largely on the preference of the operator, lag screws have the advantages of securing the graft directly against the lateral surface of the mandible, and of ease of placement. Lag screws also secure the graft to its bed better than wires do.

When the joint meniscus is unsuitable or absent, it is frequently replaced. This is done with a horizontal temporalis fascia or muscle flap, pedicled inferiorly on the coronoid process and rotated under the articular eminence of the zygomatic arch to line the joint space. The free end of the flap is secured to the soft tissues anterior to the external auditory meatus. Care is taken to place the flap so that it covers the medial surface of the natural or reconstructed condyle. If this is not achieved, medial surface can develop ankylosis to the cranial bone.

Bony reconstruction of a temporomandibular joint requires intermaxillary fixation during surgery to maintain the proper maxillomandibular relationship for effective reconstruction. The intermaxillary fixation is maintained for a variable period of time after surgery depending on the method of internal fixation. Wire internal fixation requires 4 to 6 weeks of intermaxillary fixation. Physical therapy to improve range of mandibular motion is then begun. Rigid internal fixation with screws or plates will allow release of intermaxillary fixation as early as 1 week after surgery. Physical therapy is started sooner than with wire fixation.

Discontinuity in the mandible results from resections for treatment of tumours, and osteomyelitis not responsive to debridement and antibiotics. Some benign and most malignant tumours require resection of substantial amounts of soft tissue to achieve clear margins. Benign tumours, such as ameloblastomas, if they have enlarged through the mandibular cortex also need to be resected with clear margins. Malignant tumours often require wide resection and radical neck surgery to remove tissues that are likely to contain metastases: this may compromise the soft tissue bed. Either the quantity of soft tissue to cover a bone graft reconstruction is insufficient, or there are communications to the oral cavity which lead to graft contamination. In these cases, augmentation of the local soft tissue and closure of any oral communication are required. Rotation of local pedicled flaps such as pectoralis major or deltopectoral provides such well-vascularized tissue. Free myocutaneous flaps are used as free tissue transfers. Free bone grafts from the ilium, secured with reconstruction bone plates, can be used simultaneously or later, for restoring mandibular continuity. If the bone grafts are performed later, the open approach to the mandibular inferior border, described above, is used. The length of the incision is determined by the amount of exposure needed to expose the cut ends of the mandible and to place the reconstructive plates. If flaps are in place, care is taken not to incise across vascular supply. Incisions should be made away from the flaps, and tissue pockets must be created by tunnelling under the flaps. Intermaxillary fixation of dentulous segments during surgery assures proper alignment of the jaws for accurate bone graft placement. This fixation can be released 1 or 2 weeks after surgery, but the fixation devices are useful over a longer term to provide for placement of guiding elastics to correct minor occlusal discrepancies that sometimes result.

Free transfer of a revascularized osseomyocutaneous flap is becoming more common as a means to reconstruct the mandible and soft tissue in one procedure.

Soft tissue cannot always be augmented before mandibular reconstruction. Vascular insufficiency in the host site is a common cause. This can occur when the tissues have been irradiated. A reconstructive plate alone, without bone to span the discontinuity, is helpful if there is at least enough soft tissue to accommodate its relatively small bulk. If this not possible, the discontinuity is left, and the patient is trained in a functional occlusion. Physical therapy and the use of guiding elastics attached to Kazanjian buttons or bonded appliances on convenient teeth are the keys to rehabilitation.

Accurate diagnosis must precede attempts at treatment. Plain radiographs are usually sufficient. Views from at least two directions at right angles are necessary to assess alignment and displacement. The principal mandibular views are lateral, posterior-anterior, Towne's, panoramic, and occasionally occlusal.

Teeth in the line of fracture are not removed unless they are diseased, extremely mobile, or have root fracture. Such functionless teeth are removed carefully to avoid further fracture displacement.

Fractures of the mandible are treated in closed fashion if they are not displaced and if there is functional occlusion with good intercuspation of teeth. The patient is placed on a liquid diet and cautioned not to chew. Intermaxillary fixation is used if there is concern about later displacement, patient discomfort from mandibular movement, or crepitus indicating mobility at the fracture sites. This technique encompasses the application of arch bars to the teeth with stainless steel circumdental 26-gauge wires. Elastics are applied to the lugs on the arch bars to hold the upper and lower teeth together, thus splinting the mandible for immobilization. The patient is followed weekly to check occlusion and adjust the elastics. Release is allowed at 4 weeks. Fixation can be held longer if healing is slower by clinical or radiographic examination. It is unusual for a closed reduction not to require intermaxillary fixation.

Open reduction is used when there is major displacement or mobility at the fracture sites. It is also used if a functional occlusion is absent. The open approach to the mandible, described earlier, is used by either the extraoral or intraoral route to gain access to the inferior border. Access to the inferior border of the mandible in the angle or body regions is best accomplished by the extraoral route. The inferior border at the symphysis can be conveniently approached either way.

Internal fixation of the bone is accomplished during open reduction so that stabilization can be assured. Choices include direct and figure-of-eight wires across the fractures, a Kirchner-rod attached by wires across the fracture in a groove created along the inferior border, or bone plates.

Intermaxillary fixation is applied before the open reduction to restore as much functional occlusion as possible. The bone plates allow early release of fixation, sometimes as early as the day of surgery. Other techniques require 4 weeks of intermaxillary fixation. The convenience to the patient is causing more surgeons to use plates.

Open reduction of condylar fractures is rarely indicated. Indications include dislocation of the fractured condyle out of the glenoid fossa, mandibular motion limited by the displaced condyle, and continued malocclusion 1 or 2 weeks following a closed reduction attempt. The approach is the same as the open approach to the temporomandibular joint described earlier. As in the case of temporomandibular joint reconstruction, an open approach to the inferior border of the mandible, with tunnelling in the subperiosteal plane to the fractured condylar neck, is usually added to allow convenient placement of fixation devices. These devices can be wires or miniplates.

Closed reduction with intermaxillary fixation of longer than 1 week and open reduction are avoided in children with condylar fractures, in whom these techniques cause severe limitation of mandibular motion. In general, jaw fractures in children heal more rapidly than in adults. Subsequent growth can help overcome occlusal discrepancies.

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