35: Management of Secondary Jaw Deformities after Maxillofacial Trauma

Management of Secondary Jaw Deformities after Maxillofacial Trauma

Despite the best of intentions by the primary trauma team, a subgroup of individuals who sustain facial injuries later present with deformities that require secondary reconstruction. The initial evaluation and resuscitation of the individual who has sustained craniomaxillofacial trauma is similar to that of patients with other organ system injuries. At times, the patient’s general health and other body region injuries are likely to take precedence over the management of any facial fracture. In addition, there are treatment options to consider for each craniomaxillofacial fracture, and judgment is required to select the approach that is most likely to result in a favorable outcome: open versus closed reduction; method of fixation; grafting requirements; immediate or delayed dental treatment; and the management of associated soft-tissue injuries. Treatment is individualized to accommodate the healing of each fracture and to simultaneously consider cerebral function, vision, breathing, chewing, swallowing, speech, the cervical spine, and temporomandibular joint (TMJ) injuries and to maintain cardiovascular health. Another factor is the residual facial growth requirements in a child who sustains an injury and who has not yet reached skeletal maturity. If the injured and repaired craniomaxillofacial bones do not grow normally, secondary deformities result over time. For all of these reasons, secondary deformities after facial skeletal injury (with or without effective primary repair) may occur and require later reconstruction. Specific patterns of secondary maxillofacial deformities are seen with enough frequency that each is reviewed separately.

Posttraumatic Temporomandibular Joint Ankylosis in the Pediatric Population

Background

The treatment of TMJ ankylosis poses challenges to the maxillofacial surgeon as a result of technical difficulties associated with access to the joint, the currently available autogenous and prosthetic TMJ replacement options, and the high incidence of ankylosis recurrence. Failure to restore adequate mandibular opening is likely to result in speech and swallowing impairment; difficulty with mastication; poor oral hygiene and dental neglect; continued facial growth disturbances; and the potential for airway compromise. The surgical management of bony ankylosis of the TMJ requires the complete excision of the involved osseous mass with intraoperative achievement of satisfactory passive mouth opening. The immediate reconstruction with a costochondral rib graft is often carried out, and this is followed by a postoperative physiotherapy regimen to maintain mouth opening. A number of authors have critically evaluated the treatment of TMJ ankylosis in adults, with less emphasis placed on addressing this problem exclusively in the pediatric population.*

In a study by Posnick and colleagues, a consecutive series of nine pediatric patients (mean age, 7.7 years) who underwent a standardized treatment protocol for 13 affected ankylosed temporomandibular joints was reviewed.88 Four patients had unilateral TMJ ankylosis, and five had bilateral ankylosis. One child required bilateral release but only unilateral reconstruction. Radiographic evidence demonstrated bony ankylosis in all 13 operated joints. Two patients had previously undergone surgical intervention of the TMJ. The cause of ankylosis within the study group was primarily traumatic or congenital. The protocol that was followed included complete excision of the involved ankylotic structures with mobilization through coronal scalp and Risdon neck incisions as well as the achievement of wide mouth opening. This was followed by immediate costochondral grafting. Fixation with mini-plates and screws allowed for early mobilization with the rapid institution of a physiotherapy program (Fig. 35-1).

For the study patients, despite the achievement of full passive mouth opening in the operating room, less long-term success was realized. Those with unilateral TMJ ankylosis maintained the best long-term vertical opening. On average, they went from 5 mm of maximum vertical opening (separation of the incisors) before surgery to 25 mm of active range of motion maintained for the long term. For patients with bilateral TMJ ankylosis, the maximum long-term incisal opening was only 18 mm. Mean follow-up duration at the close of the study was 2 years. Perioperative complications were minimal, with no evidence of infection, facial nerve injuries, or need for transfusion. In general, patients with unilateral or bilateral ankylosis of traumatic cause achieved satisfactory functional results after surgery, whereas those in the bilateral congenital TMJ ankylosis group attained results that were far more limited. This likely represents limitations in the intrinsic neuromotor function of the congenital cases.

Controversies and Unresolved Issues

Knowing the cause of TMJ ankylosis helps with the understanding of its pathophysiology. In developed countries, the most common etiology is trauma, followed by infection.33,48,121,125,126 Topazian found an association with trauma in 39% and with infection in 43% of patients with TMJ ankylosis (N = 229).119 Since the late 1970s, authors have found trauma to be a more frequent cause than infection, probably because of the use of antibiotics to combat the latter. In a report of a series of patients with TMJ ankylosis, Rajgopal and colleagues concluded that 80% of cases were traumatic in origin.96 Unfortunately, these reviews lumped both pediatric and adult patients together.

Surgical attempts to release TMJ ankylosis have been described dating back to 1850.5 Since then, ankylosis release followed by reconstruction using a variety of alloplastic and autogenous materials has been repoted.9,15,34,46,50,53,62,68,72,79,81,101,114,124,129 Although Gillies first described costochondral grafting for TMJ reconstruction in 1920,30 it was Poswillo93,94 and MacIntosh and Henny53 who popularized its use during the 1970s. Poswillo attempted to demonstrate the histologic and physiologic similarities between the mandibular condyle and rib cartilage in humans.93 MacIntosh and Henny described 26 cases of costochondral grafting for mandibular condyle replacement, with 6 of them being for ankylosis.53 Their approach included graft stabilization with interosseous wires and intermaxillary fixation (IMF) for 6 to 8 weeks. They claimed subsequent growth of the grafts in their pediatric patients, but they failed to provide any objective data.

In 1973, Kennett reported on two cases of unilateral TMJ ankylosis in young patients who underwent the combination of condylectomy, coronoidectomy, and reconstruction with a wired rib graft.45 He concluded that ankylosis in children should be treated as soon as possible and that recurrence is the most frequent complication. In 1986, Munro and colleagues reviewed their series of 18 adult and pediatric patients with TMJ ankylosis and facial deformity.67 Their reconstruction included interosseous wiring of the rib graft and 8 weeks of IMF followed by physiotherapy. They demonstrated better results in unilateral ankylosis cases than in bilateral cases. The next year, Lindqvist and associates described 27 patients of varying ages with TMJ ankylosis; 25 of them underwent costochondral graft reconstruction. Fixation was also by direct interosseous wires, but IMF was reduced to 3.5 weeks to encourage early mobilization and to limit recurrence. The maximum incisor opening improved from 16 mm to 31 mm. In 1987, Politis and others reported satisfactory results in six patients (five adults) with ankylosis.81 They employed a preauricular approach that involved the use of costochondral grafts and either wire or plate and screw fixation followed by 2 or 6 weeks of IMF, respectively. However, 50% of their patients developed seventh cranial nerve palsies. In 1990, Kaban and colleagues described their experience in 14 adult and pediatric patients with TMJ ankylosis and indicated satisfactory results.41,42 The protocol reported by Posnick and colleagues was similar to that of Kaban and colleagues except that the former found that the use of a mini-plate with screw fixation improved stability (as compared with interosseous wire fixation), thereby allowing for the minimal use of IMF and the early initiation of mandibular range of motion with active physiotherapy.88

In 2009, Kaban and colleagues described an updated protocol for the management of TMJ ankylosis exclusively in children.78,79,122,123 They restated their observation that the most common cause of treatment failure was inadequate resection of the ankylotic mass followed by the failure to achieve adequate passive maximum opening in the operating room. Clearly, unless adequate passive mandibular vertical opening is achieved in the operating room, failure will inevitably occur. Unfortunately, this is no guarantee that mouth opening will be maintained. Their seven-step protocol consisted of the following:

1. Complete excision of the fibrous and/or bony ankylotic mass

2. Coronoidectomy of the affected side

3. Coronoidectomy of the contralateral side if steps 1 and 2 do not result in a maximum incisal opening (>35 mm) or opening to the point of dislocation of the unaffected TMJ

4. Lining of the TMJ with either a temporalis myofascial flap or the native disc, if it can be salvaged

5. Reconstruction of the ramus condyle unit with either proximal segment osteotomy and distraction osteogenesis or costochondral graft and plate and screw fixation

6. Early mobilization of the jaws: If distraction osteogenesis is used to reconstruct the ramus condyle unit, mobilization begins the day of operation. In patients who are undergoing costochondral graft reconstruction, mobilization begins after 10 days of IMF.

7. All patients receive rigorous physiotherapy after surgery to maintain mouth opening, generally for at least 3 to 6 months

Observations and Recommendations

Several generalizations can be made about pediatric patients with TMJ ankylosis. First, in first-world countries as in the adult population, trauma remains a prevalent cause, and this is followed closely by congenital issues. In underdeveloped countries, infection continues to be an important causative factor.92 Second, although patients with unilateral ankylosis present with a severely limited preoperative opening, they are more likely to achieve satisfactory long-term functional results. Third, children with bilateral congenital TMJ ankylosis generally attain poor long-term results, despite adequate intraoperative release. This is likely the result of associated masticatory muscle anomalies, neuromuscular discoordination, or longstanding muscular disuse atrophy. Fourth, the use of mini-plate and screw fixation of the graft diminishes the need for immobilization, thereby allowing for the early institution of physiotherapy. Unfortunately, this does not guarantee the maintenance of a satisfactory long-term opening. Fifth, when a costochondral graft is used in children, only several millimeters of cartilage should remain. This is to limit the frequent complication of overgrowth and its complex secondary deformities. In clinical practice, overgrowth after costochondral grafting remains a frequent occurrence (see Chapter 28 and Fig. 35-1). Sixth, for most patients, reconstruction to achieve long-term maxillomandibular harmony must wait until they have achieved skeletal maturity (i.e., 14 to 18 years of age).

Posttraumatic Saddle-Nose Deformity

Background

Nasal injuries are often recognized but then ignored as being unimportant.11,82,86 When a depressed nasal fracture occurs in a child, injury to the growth center leaves the nose prone to a so-called “saddle deformity” with flattening of the osseocartilaginous vault.63 In general, the overlying soft tissues, the upper and lower lateral cartilages, and the nasal lining are distorted but remain intact. Reconstruction of a saddle deformity that involves the bony and cartilaginous dorsum is generally carried out with an autogenous graft (e.g., chondral, costochondral, iliac, split- or full-thickness cranial) (Fig. 35-2).27,28,32,38,60,74,91,117,118,131 The use of an allogenic graft (e.g., porous polypropylene) is always a second choice as a result of a higher incidence of associated infection and extrusion.43 The type of graft material selected (e.g., bone, cartilage, allograft), the method of fixation, the incisions required for access, the extent of dorsum that requires reconstruction, and the timing of treatment are all important details and will vary according to the age of the patient, the extent of the deformity, and the surgeon’s personal preferences (see Chapter 38).

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Figure 35-2 A 4-year-old boy fell and hit the bridge of his nose on a hard tabletop, which resulted in a saddle-nose deformity (i.e. osseous and cartilagenous vault). He arrived for evaluation when he was 8 years old and then underwent reconstruction through a coronal scalp incision with nasal osteotomies (in-fracture) and the placement of fixed crafted full-thickness cranial grafts. A, Frontal view at 3 years of age just before injury and at 8 years of age just before surgery. B, Intraoperative views through the coronal scalp incision that show the frontonasal region and the proposed right calvarial donor site. Crafted full-thickness cranial bone grafts are shown before placement for nasal reconstruction. Stabilization is achieved with microplates and screws. A close-up view of the frontonasal region shows the full-thickness cranial bone grafts in place and stabilized with microplates and screws. C, Frontal views before and 6 months after reconstruction. D, Oblique views before and 6 months after reconstruction. E, Lateral radiographs of the nose before and 6 months after reconstruction. F, Computed tomography scan views before and 6 months after reconstruction. G, Close-up lateral view just before surgery, 6 months after treatment, and then 16 years after reconstruction. A, B, C, E, F, from Posnick JC: The role of plate and screw fixation in the management of pediatric facial fractures. In Gruss JS, Manson PM, Yaremchuk MJ, eds: Rigid fixation of the craniomaxillofacial skeleton, Stoneham, Mass, 1992, Butterworth-Heinemann, p 1412.

Involvement of Both the Bone and the Cartilage Vault

The autogenous graft used (e.g., chondral, costochondral, rib, iliac, split- or full-thickness cranial) is contoured to provide reasonable nasal dorsum morphology. When the whole dorsum requires reconstruction (i.e., the radix to the nasal tip), the lower lateral cartilages are sutured over the top of the graft to provide a more natural tip contour and feel (see Fig. 35-2). When a bone graft extends from the radix to the tip, minor degrees of graft resorption at the tip should be anticipated. When correcting the saddle deformity with bone graft, freshening the base of the nasal bones with a rotary drill before graft placement is carried out; the onlay graft will then rest on a bleeding base. The accurately shaped graft is either dovetailed into a bony groove at the nasofrontal process or abutted to the frontal bones while resting evenly on the contoured and freshened)dorsal base to establish the correct nasofrontal angle. Stabilization of the bone graft is either with microplates and screws or transcutaneous Kirschner wires, depending on the access provided by the incisions that are used for the reconstruction. If a coronal scalp incision or a direct vertical nasal incision is used, plate and screw fixation is easily accommodated. An open approach (i.e., a columella splitting incision) should be combined when a coronal scalp incision is used to best manage the lower lateral cartilages and the nasal tip (see Chapter 38 and Fig. 35-2).

Involvement of the Cartilage Vault Only

When the saddle deformity causes collapse of the septal cartilage without injury to the nasal bones, then a cartilage graft reconstruction is preferred. A rib cartilage dorsal strut graft is crafted and placed flush with the nasal bones. The graft then extends caudal to the tip. The tip of the dorsal strut graft is joined to a second rib cartilage graft (caudal strut) that extends from the base of the maxilla to the nasal tip. The caudal strut is stabilized with a short buried Kirschner wire (no. 35 threaded) that is secured to the base of the maxilla/anterior nasal spine region and then pierced into the graft (Fig. 35-3). There is no advantage to harvesting the L-shaped rib cartilage graft as one unit. The separately crafted dorsal strut and caudal strut grafts are then joined together at the tip with non-resorbable suture. The lower lateral cartilages are sutured together and over the grafts to form the new nasal tip. This technique is efficient and results in a “soft” nasal tip that looks and feels natural (see Chapter 38).

Posttraumatic Orthognathic Deformities

Background

At times, the resuscitation of the trauma patient may lead to incomplete preoperative imaging and evaluation and the rushed treatment of the associated maxillofacial injuries. At other times, the primary facial fracture management is delayed by injury of multiple systems. If so, the incidence of infection, malunion, or non-union that results in secondary deformities and malocclusion is increased. In severely traumatized patients, neurologic injuries are often the main concern, especially during the first days of observation. Maxillofacial injuries may be neglected and the status of the occlusion not properly evaluated as a result of the need for orotracheal intubation, masticatory muscle spasm, difficulty assessing a comatose or uncooperative patient, or the lack of availability of a maxillofacial specialist. There may also be associated dental trauma (e.g., fracture or avulsion of the teeth) that was not recognized, neglected, or managed unfavorably in a hospital setting without available dental expertise.

Posttraumatic secondary maxillomandibular deformities may occur as a result of inadequate initial anatomic reduction or stabilization and fixation of a jaw fracture or the late resorption and remodeling of the bones resulting in malunion.23-25,35,101,105,111,115,132 The segmental loss of maxillary or mandibular dentoalveolar components may also have occurred, as discussed later in this chapter. In the child, limited growth of the bones after the initial injury (e.g., condylar fracture) or as a result of the surgical intervention carried out to reduce and stabilize the fracture may also cause secondary deformities.58,108,113

There are patterns of posttraumatic orthognathic deformities that occur with enough regularity that they are reviewed separately in the following sections of this chapter.

Malunion after Midface (Le Fort I) Fracture

An elongated face with an anterior open-bite malocclusion (counterclockwise rotated maxilla and clockwise rotated mandible) can occur when a Le Fort fracture is allowed to heal with inadequate reduction or stabilization at the time of initial management.30,40,87,132 The displaced maxilla often heals inferiorly with counterclockwise rotation. The mandible is forced into a clockwise-rotated position that involves a retrusive pogonion seen in profile. Another common reason for malocclusion after midface fracture is an unrecognized palatal split with secondary arch-form deformity.25,132 Reconstruction requires osteotomies to recreate the midface fractures followed by the surgical repositioning of the maxilla into the correct (preinjury) anatomic location. The uninjured mandible will then counterclockwise rotate to close the anterior open bite, to improve the horizontal projection at the pogonion, and to reduce the vertical height of the lower face.43,87 Another frequent scenario is when a midface fracture occurs during childhood and then results in growth disturbance. At the time of facial growth maturity (i.e., 14 to 18 years of age), maxillary hypoplasia with a skeletal class III malocclusion will be evident (Fig. 35-4).

Late Secondary Consequences of a Condylar Fracture

There are many published opposing treatment protocols for the primary management of mandibular condyle fractures.2,10,21,22,31,59,6366,112,127,133 Despite much discussion, controversy remains regarding which type of condyle fracture should be treated open rather than closed and, if operated, what approach (i.e., incisions for access, extent of condylar fragment degloving, method of fixation, postoperative immobilization and remobilization protocol) is optimal for each specific fracture. In addition, when a condyle injury or fracture occurs in a child, it can easily be overlooked or misdiagnosed, especially if the individual has no other apparent injuries. The child may not even arrive for evaluation; if evaluation does occur, the patient may be seen by a general practitioner rather than a specialist. Radiographs may be limited as a result of the need for sedation or concern by the parents about ionized radiation exposure.49,83,84

Regardless of the primary treatment rendered, a frequently seen pattern of late secondary deformity results when the condylar injury occurs prior the completion of mandibular growth (Figs. 35-5 through 35-10).26,29,69,8385,87,89,90,95,109,110 Often there is asymmetrical growth of the mandible from that point forward, with ipsilateral mandibular hypoplasia (see Chapter 4). Canting of the mandible (up on the ipsilateral side), shift of the dental midline (toward the fracture), and malocclusion (ipsilateral Class II) are frequently seen. The upper jaw is secondarily affected, growing with vertical asymmetry (canting) and with a shift of the maxillary dental midline toward the side of the fracture.

Jan 1, 2015 | Posted by in Orthodontics | Comments Off on 35: Management of Secondary Jaw Deformities after Maxillofacial Trauma
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