Part 2. Operative Technique and Exemplary Repair


■ Part 2. Operative Technique and Exemplary Repair

Following World War II and during the ensuing decades, surgical repair of combined injuries of the cranium and face was primarily (and sometimes singularly) directed toward the management of the central nervous system. Hematoma was evacuated, compromised brain and necrotic bone were débrided, dural rents were repaired, and depressed cranial bone was elevated as part of the algorithm of the day.9 , 11 15

Management of facial fractures in days past called for limited elevation of periosteum for fear of compromising the viability of the underlying bone. Orts, particularly fragments of the anterior table of the frontal sinus, were frequently discarded (see Chapter 3).16 In similar fashion, comminutions of the maxillary alveolar process were deemed unsavalgeable and summarily shed as problematic waste. Reconstruction of the craniofacial skeleton with acute bone grafting was seldom routinely considered. Halos, suspension wires, trays, oral splints, interosseous wires, transpalatal wires or bars, arch bars, and other adjuncts only partially harnessed the inherent instability of complex craniofacial segments, particularly those of the palate, and several patients experienced postoperative malocclusion and chronically altered dimensions of craniofacial form.15

Secondary repair was common months or years after injury, aided by the use of so-called foreign substances, such as methyl methacrylate. Great efforts were expended in secondary centers to restore a modicum of form and function, with secondary, even tertiary, procedures or prosthetics.

Preoperative Assessment and Indications for Repair

Clinical Presentation

Airway compromise in patients with pancraniofacial injuries is common, hemorrhage can be profound,17 and cere-brospinal fluid leak (rhinorrhea and otorrhea) should be suspected.18 20 The distortion of the craniomaxillofacial skeleton is hidden by profound edema and ecchymosis of the facial mask in the acute setting, belied by extreme instability of bone fragments. Mobility at several fracture sites, detected by bimanual examination, is, thus, a major clinical clue to the presence of a pancraniofacial injury.9

Lacerations, particularly over the glabella (central frontal boss), may communicate through frontal sinus and dura directly into the cranial cavity (see Chapter 6). Drainage of clear fluid through upper and/or midfacial lacerations is deemed to be cerebrospinal fluid until proven otherwise. Airway patency often requires intubation and tracheotomy.

As swelling abates, the extent of injury becomes more apparent. The pancraniomaxillofacial architecture is unmistakably flattened and widened. Nasal projection is lost, and the nasal pyramid tends to tilt upward, accompanied by palpable collapse of the mid and upper struts of the nose and nasoseptum.21 , 22 Comminuted fragments of the medial orbital frame are free to assume a more vertical position, and the medial canthal tendon (whether attached or avulsed from bone) may slip laterally, creating telecanthus. The malar region is flattened as the body of the zygoma is displaced posteriorly, inferiorly, and either outwardly or medially; the zygomatic arch is splayed. The volume of the orbit in one instance is constricted alarmingly in one instance (exophthalmos) and expanded in the other, causing enophthalmos.

Palatal shelves splay outwardly when fractured, creating buccal version of the maxillary dentition (see Chapter 4). The mandible fractured at the symphysis tends to splay at the mandibular angles, and there is lingual version of the alveolar bone of the anterior segment (see Chapter 5). Subcondylar fractures, if present, foreshorten the posterior segment, adding to the loss of vertical height of the face and creating premature posterior molar contact. Instability may be profound.

Radiographic Assessment

High-resolution computed tomography (HRCT) offers great detail and is able to disclose what might be occult fractures after routine radiography. Bands of comminution and the creation of small orts of bone in select areas suggest the need for bone grafting at surgery. Careful study of HRCT and three-dimensional reformats (and in the case of fractures of the symphysis of the mandible, cone beam computed tomography) facilitates early diagnosis and favors detailed treatment planning.

Force directed over the central upper face creates a radiographic pattern of central pancraniomaxillofacial fracture.5 The fracture lines typically involve the nasalnasoseptal plane, the nasomaxillary buttresses, and perhaps, the anterior table of the frontal sinus, and if so, then extend to the medial floor of the frontal sinus and the frontal sinus outflow tract (FSOFT). The medial orbital frame is often displaced medially and inwardly in central panfacial injury, disrupting the orbitoethmoid and even the orbitosphenoid buttresses (see Chapter 7). The microbuttresses of the orbit are disrupted, apparent radiographically as shattering the medial wall. The orbital apex may be involved, particularly in nonsurviving cohorts.

If the frontal sinus is large, the thick anterior table may absorb a large proportion of the load force, such that the floor and posterior table are spared. If the sinus is small, however, there is a tendency to involve the floor and posterior table. If the frontal sinus is rudimentary or fractures occur outside the sinus, large linear or segmental fractures typically traverse the nearby superior orbital rim and medial orbital roof7 , 9 , 23 , 24 ( Fig. 9.2 ).

Fracture lines may pass through the cribriform plate and roof of the sphenoid sinus, thus becoming basilar. Although these fractures tend to terminate in one of the several foramina in the greater wing of the sphenoid (see Chapter 6), fractures of the petrous ridge may be evident on HRCT, creating a temporobasilar fault.

Fig. 9.2
Fig. 9.3

Force applied in the area of the frontozygomatic suture initiates a radiographic pattern of lateral pancraniomaxillofacial fracture.5 The frontozygomatic suture may separate widely as the fault descends to divide the orbital plate of the zygoma and the greater wing of the sphenoid, disrupting the normal continuity of the lateral wall of the orbit25 (see Chapter 8) ( Fig. 9.3 ).

An ipsilateral Le Fort III pattern is often present, accompanied by a contralateral Le Fort II fracture and bilateral Le Fort fractures, identifiable as broad bands of comminution (see Chapter 4). Fractures of both processes of the zygomatic arch occur. Fractures of this type thus commonly involve the greater wing of the sphenoid and the lateral frontal sinus. The optic nerve is put at risk. In some cases, the outer reach of injury extends to the squama of the temporal or parietal bones (see Chapter 6).7 , 9

The lateral supraorbital margin is frequently damaged in lateral pancraniofacial fractures,26 and the fault may engage the lateral floor of the frontal sinus and perhaps the posterior table. The FSOFT may be spared injury in these more lateral craniofacial cases because the FSOFT descends from the medial posterior floor of the frontal sinus (see Chapter 6).

The lateral orbital wall and the lateral orbital floor, when outwardly and downwardly displaced, cause an expanded orbital volume, enophthalmos, and orbital dystopia9 (see Chapter 8). If the orbital plate of the zygoma is comminuted or the gap at the join with the greater wing of the sphenoid is large, orbital fat may herniate into the temporal fossa.

Combined central and lateral pancraniomaxillofacial fractures involve the central and lateral skull and panface after extreme load forces are applied. Instability is profound. These injuries have a higher probability of extension into the anterior, middle, or rarely posterior fossa; some 20% have associated temporal or temporobasilar bone fractures, and approximately 25% have basilarsphenoid injury.5 , 7 , 9 , 24 , 27

HRCT may also reveal fractures of the palate with splaying of the palatal shelves (see Chapter 4)28 32 and fractures of the mandible (see Chapter 5).33

Operative Repair of Pancraniomaxillofacial Fractures

Patients with pancraniomaxillofacial injuries require attentive airway management, and controlled tracheostomy (after guide-wire intubation) is commonly undertaken. Neurosurgical procedures are first accomplished and then, at the same setting, craniofacial and maxillofacial restoration is achieved.

Less injured areas are reduced first, and repair of more complex regions follows. Prealignment of fragments is commonly chosen as a prerequisite to applying plates and screws. Management is often tailored side-to-side and level-to-level as the surgeon adjusts to the vagaries of individual injury.

The introduction of plate-and-screw fixation has profoundly influenced the sequence of pancraniofacial fracture management by providing greater control of wholesale instability,8 , 10 , 34 and various philosophies have been espoused, championing one or more preferred orders of treatment, such that the repair is consummated:

  • From “bottom to top” (mandible, upper face, and midface)35

  • From “top to bottom” (frontal boss, upper face, midface, and mandible)

  • “Outside-in” (lateral orbital frame [zygomatic arch and zygoma], frontal bar and medial orbital frame, orbitoethmoid complex, palate, and mandible)8

  • “Inside-out” (palate, mandible, nasal-nasoethmoid, medial orbital frame, lateral orbital frame)36 , 37

Clark, in 2000, and numerous predecessors picture the craniofacial skeleton as having a lower “occlusal” half and an upper “structural” half for purposes of surgical intervention38 ( Fig. 9.4 ).

Fig. 9.4

The feasibility of this conceptualization has been enhanced by the successful outcomes that have followed use of locking plates and screws for repair of the fractured palate and mandible32 , 39 (see Chapters 3, 4, and 5). Like the building of a sanctuary (see Chapter 1), the rigid maxillomandibular block is then able to act as a platform for reconstruction of subsequent suprastructure.34 The lower facial width, depth, and height and the occlusion are the first in pancraniofacial restoration to be declared when this sequence is chosen.

For purposes of treating most pancraniofacial injury, the author pictures the craniofacial skeleton as having three segments, rather than “halves”: lower facial, cranial, and upper facial. The lower facial segment consists of the palate, mandible, and the lower aspect of the anterior maxillary buttresses as they are launched from the maxillary alveolus. The anterior cranial segment consists of the aggregate created by the frontal, sphenoid, temporal, lacrimal, and ethmoid bones. The upper facial segment consists of the central upper face, the lateral upper face, the nasal-nasoseptal complex, and upper portions of the maxilla ( Fig. 9.5 ).

The order of management varies according to patient need once operative intervention is under way. Nevertheless, the algorithm in Fig. 9.6 has been effective in patients with pancraniofacial injury, such that locking plates and screws are first used to control wayward palatal shelves and mandibular fragments.

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Jul 2, 2020 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Part 2. Operative Technique and Exemplary Repair
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