Lower jaw damages in peacetime and in extreme conditions: damage anatomy, classification, clinic course, medical help for wounded on the medical evacuation. Hand treatment of the surgeon when lower jaw damaged, principles of plastic surgery.
Management of trauma has always been one of the surgical subsets in which oral and maxillofacial surgeons have excelled over the years. More particularly, our experience with dental anatomy, head and neck physiology, and occlusion provides us with unparalleled skills for the management of mandibular fractures. The mandible is the second most commonly fractured part of the maxillofacial skeleton because of its position and prominence.1,2 The location and pattern of the fractures are determined by the mechanism of injury and the direction of the vector of the force. In addition to this, the patient’s age, the presence of teeth, and the physical properties of the causing agent also have a direct effect on the characteristics of the resulting injury.3 Bony instability of the involved anatomic areas is usually easily recognized during clinical examination. Dental malocclusion, gingival lacerations, and hematoma formation are some of the most common clinical manifestations. In the management of any bone fracture, the goals of treatment are to restore proper function by ensuring union of the fractured segments and reestablishing preinjury strength; to restore any contour defect that might arise as a result of the injury; and to prevent infection at the fracture site. Restoration of mandibular function, in particular, as part of the stomatognathic system must include the ability to masticate properly, to speak normally, and to allow for articular movements as ample as before the trauma. In order to achieve these goals, restoration of the normal occlusion of the patient becomes paramount for the treating surgeon. Basic principles of orthopedic surgery also apply to mandibular fractures including reduction, fixation, immobilization, and supportive therapies. It is well known that union of the fracture segments will only occur in the absence of excessive mobility. Stability of the fracture segments is key for proper hard and soft tissue healing in the injured area.
Therefore, the fracture site must be stabilized by mechanical means in order to help guide the physiologic process toward normal bony healing. Reduction of the fracture can be achieved either with an open or closed technique. In open reduction, as the name implies, the fracture site is exposed, allowing direct visualization and confirmation of the procedure. This is typically accompanied by the direct application of a fixation device at the fracture site (Figure 22- 1). A closed reduction takes place when the fracture site is not surgically exposed but the reduction is deemed accurate by palpation of the bony fragments and by restoration of the functioning segments, for example, restoration of the dental occlusion by wiring the teeth together, using splints, or employing external pins (Figure 22-2). Fixation must be able to resist the displacing forces acting on the mandible. It can take one of two forms: direct or indirect.
When direct fixation is used, the fracture site is opened, visualized, and reduced; then stabilization is applied across the fracture site. The rigidity of direct fixation can range from a simple osteosynthesis wire across the fracture (ie, nonrigid fixation) to a miniplate at the area of fracture tension (ie, semirigid fixation) or a compression bone plate (ie, rigid fixation) to compression screws alone (lag screw technique). Indirect fixation is the stabilization of the proximal and distal fragments of the bone at a site distant from the fracture line. The most commonly used method for mandibular fractures is the use of intermaxillary fixation (IMF). A further example of indirect fixation is the use of external biphasic pin fixation in combination with an external frame (Figure 22-3). Over the past three decades many different techniques and approaches have been described in the literature to surgically correct facial fractures.
More recently the use of internal fixation utilizing plates has shown the highest success rates with the lowest incidence of nonunions and postoperative infections.4–6 The origin of plating as a treatment option for fractures can be traced to Dannis and colleagues, who reported the successful use of plates and screws for fracture repair in 1947.7 Later refinement of this technique is credited to Allgower and colleagues at the University of Basel, who successfully used the first compression plate for extremity fracture repair in 1969.8 However, it was not until 1973 that Michelet and colleagues reported on the use of this treatment modality for fractures of the facial skeleton. 9 In 1976 following Michelet’s success, a group of French surgeons headed by Champy developed the protocol that is now used for the modern treatment of mandibular fractures. But it was not until 1978 that these findings were published in the English literature.10 Basically, there are two categories of plating systems: rigid compression plates such as the AO/ASIF (Arbeits-gemeinschaft fur Osteosynthesefragen/Association for the Study of Internal Fixation) and the semirigid miniplates. The advantages and disadvantages of each system have been extensively discussed; however, the question remains: does compression of fractures really offer a clinically significant advantage in terms of better bone healing and fewer complications? Proponents of the AO system state that primary or direct bone healing is the main advantage offered by this system. When a fracture is compressed, absolute interfragmentary immobilization is achieved with no resorption of the fragment ends, no callus formation, and intracortical remodeling across the fracture site whereby the fractured bone cortex is gradually replaced by new haversian systems.11 However, in other studies it has been shown that absolute rigidity and intimate fracture interdigitation is far from mandatory for adequate bony healing. Compression is not necessary at the fracture site for healing, and it is questionable whether compression stimulates osteogenesis.12,13
Biomechanical Considerations
Studies of the relationship between the nature, severity, and direction of traumatic force on the resultant mandibular injury were made by Huelke and colleagues.14–19 Before this, few experimental studies had been done with regard to the mechanism of mandibular fracture.Most literature regarding the mechanism of fracture was based on clinical impressions and opinions. Early investigators showed that linear fractures in long bones were initiated by bone failure resulting from tensile strain rather than compressive strain.20 Huelke and Harger applied forces of varying magnitudes and direction to dried mandibles and observed the resultant production of tension and compression.17 They found that > 75% of all experimentally produced fractures of the mandible were in primary areas of tensile strain, which supported a similar observation made earlier in long bones. A notable exception was that comminuted condylar head injury that was produced by a load parallel to the mandibular ramus was primarily the result of compressive force. In response to loading, the mandible is similar to an arch because it distributes the force of impact throughout its length (Figure 22-4). However, unlike the arch, the mandible is not a smooth curve of uniform bone, but rather it has discontinuities such as foramina, sharp bends, ridges, and regions of reduced cross-sectional dimension like the subcondylar area. As a result, parts of the mandible develop greater force per unit area, and consequently, tensile strain is concentrated in these locations. When a force is directed along the parasymphysis-body region of the mandible, compressive strain develops along the buccal aspect, whereas tensile strain develops along the lingual aspect. This produces a fracture that begins in the lingual region and spreads toward the buccal aspect.17 The mobile contralateral condylar process moves in a direction away from the impact point until it is limited by the bony fossa and associated soft tissue. At this point, tension develops along the lateral aspect of the contralateral condylar neck, and a fracture occurs. If greater force is applied to the parasymphysis- body region, not only will tension develop along the contralateral condylar neck leading to fracture in this area, but continued medial movement of the smaller ipsilateral mandibular segment will lead to bending and tension forces along the lateral aspect and subsequent fracture of the condylar process on the ipsilateral side. Force applied directly in the symphysis region along an axial plane is distributed along the arch of the mandible.
Because the condylar heads are free to rotate within the glenoid fossa to a certain degree, tension develops along the lateral aspect of the condylar neck and mandibular body regions, as well as along the lingual aspect of the symphysis. This leads to bilateral condylar fractures and a symphysis fracture (Figure 22-5). Variation from these standard fracture patterns occurs for two general reasons. First, there is a wide range in the possible magnitude and direction of the impact and in the shape of the object delivering the impact. Second, the condition of the dentition, position of the mandible, and influence of associated soft tissues could not be controlled in these studies. Early observers felt that the presence of posterior dentition tended to reduce the incidence of condylar injury.21–23 The implication was that, as the mandible was forced posteriorly and superiorly, the dentition would meet and absorb some of the force, thereby diminishing the force received at the condyle.
This was supported by the clinical observation that the posterior dentition was often fractured on the side of the condylar fracture. However, more recent findings do not support this theory and show that all types of fractures occur, irrespective of the occlusion, and that no correlation exists between the degree of dislocation, level of fracture, or type of fracture with the presence of a distal occlusion. 24 Although the presence or absence of a posterior dentition does not correlate with the incidence of fracture, the presence of specific teeth, particularly impacted third molars, has been shown to markedly affect the incidence of mandibular fractures. It was shown that, when impacted third molars are present, this area represented a region of inherent weakness and the incidence of condylar fractures decreases, whereas the incidence of mandibular angle fractures increases.25 Although unable to show that the occlusion played any role in the type of fracture produced, investigators have found that the relative degree of mandibular opening at the time of impact does play an important role in the type of fracture that occurs.23,26 More recent studies have shown that not only is the incidence of fracture higher when the mouth is open, but the level of fracture varies with degree of opening. When the mouth is opened, the fractures tend to be located more in the condylar neck or condylar head region, whereas when it is closed, fractures are in the subcondylar area.
Evaluation of Mandibular Fractures
Traumatic craniofacial and skull base injuries require a multidisciplinary team approach. Trauma physicians must evaluate carefully, triage properly, and maintain a high index of suspicion to improve survival and enhance functional recovery. Frequently, craniofacial and skull base injuries are overlooked while treating more life-threatening injuries.27 Unnoticed complex craniofacial and skull base fractures, cerebrospinal fluid fistulas, and cranial nerve injuries can result in blindness, diplopia, deafness, facial paralysis, or meningitis. Following the principles of Advanced Trauma Life Support, during the initial assessment in the emergency department, the first and most critical obligation is to make sure that the airway is patent and free of potential obstruction. The tongue, which may have a tendency to fall back, must be controlled, and objects obstructing the airway must be removed. If an obstruction cannot be removed, a new airway must be established by endotracheal intubation (remembering possible cervical spine injuries) or cricothyrotomy. After the airway has been secured and respiration is occurring, vital signs must be assessed, including pulse rate and blood pressure. Any significant blood loss is likely to be coming from injuries apart from those of the face. Other critical injuries must be ruled out, including intracranial hemorrhages, cervical and other spinal injuries, chest injuries, abdominal trauma, and fractures of the long bones. Local examination of the face and jaws should be conducted in a logical sequence. The first objective is to obtain an accurate history from the patient, or relative if the patient cannot cooperate.
Evaluation of Mandibular Fractures
Traumatic craniofacial and skull base injuries require a multidisciplinary team approach. Trauma physicians must evaluate carefully, triage properly, and maintain a high index of suspicion to improve survival and enhance functional recovery. Frequently, craniofacial and skull base injuries are overlooked while treating more life-threatening injuries.27 Unnoticed complex craniofacial and skull base fractures, cerebrospinal fluid fistulas, and cranial nerve injuries can result in blindness, diplopia, deafness, facial paralysis, or meningitis. Following the principles of Advanced Trauma Life Support, during the initial assessment in the emergency department, the first and most critical obligation is to make sure that the airway is patent and free of potential obstruction. The tongue, which may have a tendency to fall back, must be controlled, and objects obstructing the airway must be removed. If an obstruction cannot be removed, a new airway must be established by endotracheal intubation (remembering possible cervical spine injuries) or cricothyrotomy. After the airway has been secured and respiration is occurring, vital signs must be assessed, including pulse rate and blood pressure. Any significant blood loss is likely to be coming from injuries apart from those of the face. Other critical injuries must be ruled out, including intracranial hemorrhages, cervical and other spinal injuries, chest injuries, abdominal trauma, and fractures of the long bones. Local examination of the face and jaws should be conducted in a logical sequence. The first objective is to obtain an accurate history from the patient, or relative if the patient cannot cooperate. Pertinent to a dentition on the same side as the condylar fracture (Figure 22-8).
If bilateral condylar fractures are present, the occlusion may not be deviated. The midlines are often coincident, and premature contact is present bilaterally on the posterior dentition with an anterior open bite. The posterior dentition may be fractured on both sides in these situations. Often the patient with a fracture of the condylar process also has a limited range of motion. This limitation, however, is primarily caused by voluntary restriction as a result of pain. One has to keep in mind that any limitation of mandibular movement may also be a result of reflex muscle spasm, temporomandibular effusion, or mechanical obstruction to the coronoid process resulting from depression of the zygomatic arch. Other less common findings include blood within the external auditory canal and, in the case of fracture dislocation, development of a prominent preauricular depression. Careful otoscopic evaluation of the external auditory canal is of particular importance in patients suspected to have suffered an injury at this level. Occasionally a fracture of the condylar process will produce a tear in the epithelial lining of the anterior wall of the canal, which produces bleeding from the acoustic meatus. It is important to determine that this bleeding is not coming from behind a ruptured tympanic membrane, which may signify a basilar skull fracture. A detailed intraoral examination should be undertaken with good lighting and immediate availability of suction. The most common intraoral findings are malocclusion, fracture of the dentition, and decreased interincisal opening. Continuing with the systematic evaluation of the patient, it is suggested that examination of the soft tissues be undertaken next. The gingival tissue should be inspected for tears or lacerations.With the aid of a tongue blade, the floor of the mouth is examined; sublingual ecchymosis is almost pathognomonic of a fracture of the mandible. Next the dentition is examined for evidence of broken teeth and for steps or irregularities in the dental arch. The patient is asked to lightly bite the teeth together and to say whether the bite feels different from normal, following which the occlusion is inspected. Premature occlusal contacts are noted. The three causes of an altered occlusion in the trauma patient are a displaced fracture, a dental injury such as a displaced tooth, and a temporomandibular joint effusion or dislocation. If the patient is edentulous and has intact dentures with him, these can be replaced in the mouth and the occlusion inspected (Figure 22-9).
The mandible should then be grasped on each side of any suspected fracture and gently manipulated to assess mobility. If no fracture can be found but clinical suspicion remains high, the mandible may be compressed by applying pressure over both angles (Figure 22-10).
This nearly always gives rise to pain at a fracture site. In the case of subcondylar fractures, firm posterior pressure on the chin will cause pain in the preauricular region.
Radiographic Evaluation
To adequately screen for the presence of a mandibular fracture, at least two views at right angles to each other are necessary. A panoramic radiograph and a reverse Towne’s view (Figure 22-11) are adequate screening studies for this purpose. If only one view is used, fractures can easily be missed.28 In the multiple-trauma patient for whom panoramic radiographs are not possible, lateral oblique views may be substituted. Other radiographic views that may be useful depending on the circumstances are posteroanterior mandibular, mandibular occlusal, and periapical. Linear tomographies of the temporomandibular joints can also be useful in the evaluation of fractures at the level of the condylar process. However, intracapsular fractures
of the condylar head are often difficult to visualize accurately on plain films. The typical radiographic findings when a condylar fracture is present are the following: a shortened condylar-ramus length; the presence of a radiolucent fracture line or, in the case of overlapped segments, the presence of a radiopaque double density (Figure 22-12); and evidence of premature contact on the side of the fracture if the radiograph was taken with the patient in occlusion. If more accurate information of the involvement of the temporomandibular joint is required, axial and coronal computed tomography (CT) scans offer an excellent opportunity to study the fracture details. Indications for CT scans are the following: 1. Significant displacement or dislocation, particularly if open reduction is contemplated 2. Limited range of motion with a suspicion of mechanical obstruction caused by the position of the condylar segment 3. Alteration of the surrounding osseous anatomy by other processes, such as previous internal derangement or temporomandibular joint surgery, to the degree that a pretreatment baseline is necessary 4. Inability to position the multipletrauma patient for conventional radiographs (CT scans may be the only useful radiograph that can be obtained) Chayra and colleagues reviewed the need for a complete series of films.29 They concluded that the initial screening of patients could be effectively undertaken with a panoramic radiograph alone.Ninetytwo percent of fractures were seen on a panoramic radiograph alone, compared with only 66% on a routine radiographic series without a panoramic view. However, in order to accurately visualize displacement it is recommended that the standard mandibular views consist of a panoramic radiograph, a posteroanterior mandibular view, and reverse Towne’s view (Figure 22- 13). The latter view allows for visualization of the degree of medial or lateral displacement of the fracture and unveils injuries in which only subtle deviation is present, such as is seen in greenstick fractures, which are not readily evident on panoramic view. The panoramic radiograph usually requires the patient to be able to stand upright and also requires accurate patient positioning for good-quality films. In the severely traumatized patient, this may be difficult to achieve with some machines. Further, mesiolateral displacement in the ramus and body and anteroposterior displacement in the symphyseal regions may also be difficult to visualize. The traditional lateral oblique views of the mandible can be used when panoramic films are not possible. They require accurate positioning of the patient and film to obtain useful views, particularly in the condylar area. A transcranial temporomandibular view may be a good addition in these circumstances. Accurate assessment of symphyseal fractures may be problematic with the standard views. A mandibular occlusal view is particularly useful in this scenario. It also aids in the assessment of the fracture of the lingual plate, particularly in very oblique fractures. Periapical views may also be necessary for evaluation of the teeth on either side of the fracture line to assess root fractures, periapical and periodontal pathology, and the relationship of the fracture line to the periodontal ligament of each tooth.
Classification
The first step in the development of an appropriate treatment plan is to establish a clear understanding of the type of injury the patient has suffered, in order to provide an adequate surgical solution. In the diagnostic work-up phase, the lack of standardized ways to assess and characterize the nature and severity of the orofacial injury engenders variation in practice patterns.30 Probably the most basic question one should ask at the initial evaluation is whether the fractures are displaced or nondisplaced. Depending on the amount of energy transmitted to the facial skeleton and the vector in which such force is directed, there will be more or less disruption of the normal anatomic structures. Muscle attachment and their counteracting forces also play a primary role in the pattern and direction of the fractures. It is the displacing forces of the muscles of mastication that influence favorableness (Figures 22-14 and 22-15). The principle of favorableness is based on the direction of a fracture line as viewed on radiographs in the horizontal or vertical plane. A horizontally favorable fracture line resists the upward displacing forces, such as the pull of the masseter and temporalis muscles on the proximal fragment when viewed in the horizontal plane. A vertically favorable fracture line resists the medial pull of the medial pterygoid on the proximal fragment when viewed in the vertical plane. In the parasymphyseal region of the mandible, the combined action of the suprahyoid and digastric muscles on a bilateral fracture can pull on the distal fragment inferiorly in unfavorable fractures, putting the patient at risk for acute upper airway obstruction. The first concern is whether there are indeed fractures present, and if there are, where they are located anatomically. Mandibular fractures may be further classified by the pattern of fracture (Figure 22- 16) present and by anatomic location. Many systems of classification have been applied to fractures involving the mandibular condyle.24,31–35The recommended classification parallels the comprehensive classification set forth by Lindahl. 24 As mentioned before, it is imperative that radiographs be taken of the suspected injury in two planes at right angles to each other. The following major relations are noted: the level of the fracture; the relation of the condylar fragment to the mandible, termed the degree of displacement; and the relation of the condylar head to the fossa, or the degree of dislocation.
Anatomic Location
The following classification has been modified from Kelly and Harrigan’s epidemiologic study in which they divided mandibular fractures based on their anatomic location36: • Dentoalveolar fracture: Any fracture that is limited to the tooth-bearing area of the mandible without disruption of continuity of the underlying osseous structure • Symphysis fracture: Any fracture in the region of the incisors that runs from the alveolar process through the inferior border of the mandible in a vertical or almost vertical direction • Parasymphysis fracture: A fracture that occurs between the mental foramen and the distal aspect of the lateral mandibular incisor extending from the alveolar process through the inferior border • Body fracture: Any fracture that occurs in the region between the mental foramen and the distal portion of the second molar and extends from the alveolar process through the inferior border • Angle fracture: Any fracture distal to the second molar, extending from any point on the curve formed by the junction of the body and ramus in the retromolar area to any point on the curve formed by the inferior border of the body and posterior border of the ramus of the mandible • Ascending ramus fracture: A fracture in which the fracture line extends horizontally through both the anterior and posterior borders of the ramus or that runs vertically from the sigmoid notch to the inferior border of the mandible • Condylar process fracture: A fracture that runs from the sigmoid notch to the posterior border of the ramus of the mandible along the superior aspect of the ramus; fractures involving the condylar area can be classified as extracapsular or intracapsular, depending on the relation of the fracture to the capsular attachment Pattern of Fracture The following classification is based on pattern of fracture (see Figure 22-16):
• Simple fracture: A simple fracture consists of a single fracture line that does not communicate with the exterior. In mandibular fractures this implies a fracture of the ramus or condyle or a fracture in an edentulous portion with no tears in the periosteum. • Compound fracture: These fractures have a communication with the external environment, usually by the periodontal ligament of a tooth, and involve all fractures of the tooth-bearing portions of the jaws. In addition, if there is a breach of the mucosa leading to an intraoral communication or a laceration of the skin communicating with the fracture site, edentulous portions of the mandible may be involved. • Greenstick fracture: This type of fracture frequently occurs in children and involves incomplete loss of continuity of the bone. Usually one cortex is fractured and the other is bent, leading to distortion without complete section. There is no mobility between the proximal and distal fragments. • Comminuted fractures: These are fractures that exhibit multiple fragmentation of the bone at one fracture site. These are usually the result of greater forces than would normally be encountered in simple fractures. • Complex or complicated fracture: This type of injury implies damage to structures adjacent to the bone such as major vessels, nerves, or joint structures. This usually implies damage to the inferior alveolar artery, vein, and nerve in mandibular fractures proximal to the mental foramen and distal to the mandibular foramen. On rare occasions a peripheral branch of the facial nerve may be damaged or the inferior alveolar nerve injured in subcondylar fractures. • Telescoped or impacted fracture: This type of injury is rarely seen in the mandible, but it implies that one bony fragment is forcibly driven into the other. This type of injury must be disimpacted before clinical movement between the fragments is detectable. • Indirect fracture: Direct fractures arise immediately adjacent to the point of contact of the trauma, whereas indirect fractures arise at a point distant from the site of the fracturing force. An example of this is a subcondylar fracture occurring in combination with a symphysis fracture. • Pathologic fracture: A pathologic fracture is said to occur when a fracture results from normal function or minimal trauma in a bone weakened by pathology. The pathology involved may be localized to the fracture site, such as the result of a cyst or metastatic tumor, or as part of a generalized skeletal disorder, such as osteopetrosis. • Displaced fracture: Fractures may be nondisplaced, deviated, or displaced. A nondisplaced fracture is a linear fracture with the proximal fragment retaining its usual anatomic relationship with the distal fragment. In a deviated fracture, a simple angulation of the condylar process exists in relation to the remaining mandibular fragment, without development of a gap or overlap between the two segments. Displacement is defined as movement of the condylar fragment in relation to the mandibular segment with movement at the fracture site. The fragment can be displaced in a lateral, medial, or anteroposterior direction. In displaced fractures the articular surface of the condyle remains within the glenoid fossa and does not herniate through the joint capsule. • Dislocated fracture: A dislocation occurs when the head of the condyle moves in such a way that it no longer articulates with the glenoid fossa. When this is associated with a fracture of the condyle, it is termed a fracture dislocation. Fracture dislocations are discussed more completely later in this chapter. The mandibular condyle may also be dislocated as a result of trauma without an associated condylar fracture. Dislocations can occur anteriorly, posteriorly, laterally, and superiorly. • Special situations: Other types of fractures that do not readily fit the above classification include grossly comminuted fractures or fractures involving adjacent bony structures, such as the glenoid fossa or tympanic plate; open or compound fractures; and fractures in which a combination of several different types of fractures exist. Open fractures of the condyle are usually caused by missiles such as bullets.
Nonfracture Injuries of the Articular Apparatus
The most commonly documented result of trauma to the articular apparatus and mandibular condyle is fracture. Other injuries occur as well and must be considered in the differential diagnosis (Table 22-1). Anterior dislocation occurs when the condyle moves anterior to the articular eminence. This is by far the most common situation and represents a pathologic forward extension of the normal translational movement of the condylar head. Unlike subluxation, which is also a forward extension of the condyle, dislocation is not selfreducing. Dislocation may be caused by yawning, oral sex, phenothiazine use, and trauma. Traumatically induced anterior dislocation is most commonly bilateral, but it may occur unilaterally (particularly if associated with a concomitant fracture elsewhere in the mandible). The diagnosis of an anteriorly dislocated mandible is made by the following clinical features: an anterior open bite with the inability to close the mouth; severe pain in the region anterior to the ear; absence of the condyle from the glenoid fossa with a visible and palpable preauricular depression; inability to move the mandible except to open the mouth slightly in a purely rotational manner; difficulty in speaking; and a prognathic lower jaw. Finally, if unilateral dislocation is present, the chin will be deviated to the opposite side (Figure 22-17). Patients with anterior dislocation of the mandibular condyles without other mandibular trauma should be approached using the following treatment protocol: 2 cc of local anesthetic solution should be deposited into the joint capsule followed by manual reduction. If this is unsuccessful or the patient is overly apprehensive, diazepam should be carefully titrated intravenously followed by further attempts at manual reduction. If these measures fail, then general anesthesia with the use of a muscle relaxant may be necessary.37 It is usually possible to reduce an acute dislocation with these maneuvers. In refractory cases or in cases associated with mandibular body and angle fractures in which the dislocated segment is difficult to control by manipulation, surgical intervention may be required. A percutaneous bone hook placed through the sigmoid notch or wires placed through the angle of the mandible allow for additional downward traction.38,39 Following successful reduction, the patient should be instructed to refrain from opening his or her mouth widely and to support the jaw with a hand under the chin when yawning for a period of 3 weeks to allow for healing of the injured soft tissue in and around the joint. IMF is not necessary for a first-time acute anterior dislocation of the jaw, unless it persistently dislocates after reduction. In persistent, recurrent dislocation, contributing factors, such as phenothiazine use, should be identified. A soft diet may also be recommended for several days along with a nonsteroidal anti-inflammatory analgesic. When a blow to the mandible produces primarily a posterior vector of force and does not result in fracture of the condylar neck, the head of the condyle may be forced into a posterior dislocation. This injury is frequently associated with laceration and fracture of the external auditory canal leading to hemorrhage that is visible at the external acoustic meatus.26 In most cases maintenance of the patient’s occlusion and treatment of the associated ear injuries are the only management procedures necessary. Lateral dislocation of the condylar head is always associated with a concomitant fracture either of the condyle or elsewhere within the mandible. The diagnosis of this condition is straightforward. The condylar head is palpable as a hard mass either in the preauricular region or in the lower part of the temporal space. This type of injury is associated with a marked crossbite, which is not attributable solely to the mandibular fracture but instead is secondary to the displaced condyle. Treatment requires reduction of the dislocation through manipulation of the dislocated segment by grasping it with a thumb on the dentition and with the fingers extraorally along the body of the mandible. If the proximal segment size is inadequate for this maneuver, a percutaneous towel clip through the angle or a small incision with placement of a wire through the angle (as described for anterior dislocation) may be necessary. After reduction of the dislocation, treatment of the associated fracture is accomplished, preferably with rigid internal fixation. Superior dislocation into the middle cranial fossa without associated fracture of the mandibular condyle has been described. The patient is predisposed to this type of dislocation when the condylar head is small and rounded.40
This injury is more common when the mouth is open at the moment of impact.41 This type of injury usually occurs with concomitant midface fractures that are telescoped, causing shortening of the vertical dimension of the face and allowing superior dislocation of the mandibular condyle. Superior dislocation of the mandibular condyle is associated with cerebral contusion and basilar skull fracture with facial nerve paralysis and deafness. These patients present with severe restriction of interincisal opening, pain in the area of the temporomandibular joint, bleeding from the external auditory canal or hemotympanum, and deviation of the jaw to the affected side. A variety of treatment modalities are recommended, including observation, condylotomy, elastic traction, condylectomy, and manual reduction.42 Neurosurgical consultation is required. Effusion and hemarthrosis of the temporomandibular joint after trauma occur similarly as in other joints.23 In most cases this leads to a distention of the joint capsule with varying amounts of discomfort. Frequently deviation of the mandible away from the affected side occurs as a result of downward pressure on the condyle from the production of fluid within the joint. This produces facial asymmetry and malocclusion (Figure 22-18). The treatment of traumatically induced effusions of the temporomandibular joint is aimed at the restoration of preinjury occlusion with return to function and relief of pain. If the patient presents with the subjective symptoms of a joint effusion but has a stable and reproducible occlusion, the condition may be managed with close daily observation, nonsteroidal anti-inflammatorv medications, and a soft diet. Frequently the condition will resolve in a matter of days. If, however, the malocclusion is significant enough that the patient is unable to achieve a stable occlusion without manipulation of the jaw, Ivy loop wiring or arch bars should be placed and guiding elastics used to produce a stable occlusion. Arthrocentesis, arthroscopy, or both are common therapies for hemarthrosis in other joints and may also be considered.43 Regardless of the therapy chosen, care should be taken to avoid excessive IMF because this may result in a long-term limitation of function. It has been suggested that this limitation in function is a result of organization of the blood within the joint space with development of fibrosis and subsequent ankylosis. Many authors have emphasized the importance of this proposed mechanism in the development of ankylosis.44,45 Aspiration or arthroscopic lavage may alleviate this. It is possible, however, that the development of limited function and ankylosis is more dependent on the inability to maintain a full range of motion during the IMF period rather than on the hemarthrosis. This theory is supported by the failure of experimentally induced hemarthroses to produce ankylosis, 46 and by the absence of ankylosis and limited function after iatrogenically induced hemarthroses during joint injections or arthroscopy.47 Most likely, decreased range of motion after joint effusion is the result of intra-articular fibrosis potentiated by prolonged IMF.
Treatment of Mandibular Fractures
Fractures of the mandible have been reported to comprise between 40 and 62% of all facial fractures,36, 48, 49 although these figures may not represent the true incidence because isolated nasal fractures are seldom included in such surveys. If these injuries are taken into account, the occurrence of mandibular fractures decreases to anywhere between 10 and 25% of all facial fractures depending on the mechanism of injury.50 The literature is consistent on the fact that about one-half of all patients who suffer mandibular fractures are involved in a motor vehicle accident.2,48,51–53 Males are overwhelmingly reported to be affected more frequently than females in a ratio ranging from 3:1 to 7:1 depending on the survey and especially the country involved.48,54,55 Predictably, such studies reveal the most susceptible age group for both sexes is between 21 and 30 years of age.54,56,57 In most cases, mandibular fractures are encountered in isolation from any other facial fractures. But different studies have revealed that almost 20% of these patients have concomitant fractures in other anatomic structures of the facial skeleton,58–60 with the most common one being the zygomaticomaxillary complex.61 Further injury away from the facial region may also be present, including multiplesystem trauma. In the study by Ellis and colleagues of 2,137 patients with mandibular fractures, 10.5% of subjects sustained other injuries outside the maxillofacial region.48 Injury patterns are largely dependent on the mechanism of injury, with patients involved in motor vehicle accidents sustaining a great percentage of other injuries. The distribution of principal fracture sites has been reported as 33% involving the body, 29% in the condylar region, 23% the angle, and 8% in the symphysis region (Figure 22-19).
It is not unusual to sustain more than one fracture site in the mandible. Mandibular fractures are multiple in more than 50% of the cases.48,62,63 The left side is more commonly involved, in particular the left angle, probably because most assailants are right-handed and the left side of the jaw would be the side most likely to be struck.57 Falls show a greater proportion of subcondylar fractures, as high as 36.3% in one study.49 When multiple fractures of the mandible are considered, the most common combinations are angle and opposite body, bilateral body, bilateral angle, and condyle and opposite body (Figure 22-20).
The site of fracture is also determined by the size, direction, and surface area of the impacting blow. An impact to the chin with a line of force through the symphysis and temporomandibular joints will produce a single subcondylar fracture at 193 kg (425 lb.) and a bilateral subcondylar fracture at about 250 kg (550 lb.), whereas symphyseal fractures require force between 250 and 408 kg (900 lb.).64 An impact to the lateral aspect of the mandibular body using a 2.5 × 10 cm (1 × 4 in.) impact surface will produce a mandibular fracture at 136 to 317 kg (300–700 lb.). When an impact force is delivered to the mandible, the bone bends inward, producing compressive forces on the impacted (lateral) surface and tensile forces on the lingual (medial) surfaces of the bone opposite the impact site.18 Fracture results when the tensile strain overcomes the resistance of the bone, beginning on the medial side of the mandible and progressing through the bone toward the impact point. Direct fracture may occur at the site of impact, but additional indirect fractures may result when higher forces are involved. An example would be a blow to the left angle, causing a direct fracture at the left-angle region and an indirect fracture in the right body. Occasionally, only indirect fracture results, usually in the subcondylar area as, for example, when a blow on the chin results in a fracture of either condylar neck. Indirect fractures demonstrate the opposite tensile strain patterns and fracture outcomes from those of the direct fracture; that is, the tensile strain develops on the side opposite to the impact. In the case of greenstick fractures, the fracture occurs on the tension side and bending occurs on the compression side.
The initial assessment and management of a patient’s injuries must be completed in an accurate and systematic manner to quickly establish the extent of any in juryto vital life-support systems. Nearly 25 to33% of deaths caused by injury can be prevented when an organized and systematic approach is used.1Significant data exist to suggest that death from trauma has a trimodal distribution.2 The first peak on a linear distribution of deaths is within seconds or minutes of the injury. Invariably these deaths are due to lacerations of the brain, brainstem, upper spinal cord, heart, aorta, or other large vessels. Few of these patients can be saved, although in areas with rapid transport, a few of these deaths have been avoided. The second death peak occurs within the first few hours after injury. The period following injury has been called the “golden hour” because these patients may be saved with rapid assessment and management of their injuries. Death is usually due to central nervous system (CNS) injury or hemorrhage. Recent analysis of trauma system efficacy suggests that trauma deaths could be reduced by at least 10% through organized trauma systems. These patients, whose numbers are significant, benefit most from regionalized trauma care.3 The third death peak occurs days or weeks after the injury and is usually due to sepsis, multiple organ failure, or pulmonary embolism.4 Patients are assessed and treatment priorities are established based on patients’ injuries and the stability of their vital signs. In any emergency involving a critical injury, logical and sequential treatment priorities must be established on the basis of overall patient assessment. Injuries can be divided into three general categories: severe, urgent, and nonurgent. 2 Severe injuries are immediately life threatening and interfere with vital physiologic functions; examples are compromised airway, inadequate breathing , hemorrhage, and circulatory system damage or shock. These injuries constitute approximately 5% of patient injuries but represent over 50% of injuries associated with all trauma deaths. Urgent injuries make up approximately 10 to 15% of all injuries and offer no immediate threat to life. These patients may have injuries to the abdomen, orofacial structures, chest, or extremities that require surgical intervention or repair, but their vital signs are stable. Nonurgent injuries account for approximately 80% of all injuries and are not immediately life threatening. This group of patients eventually requires surgical or medical management, although the exact nature of the injury may not become apparent until after significant evaluation and observation. Laboratory studies, additional physical findings, radiographic examinations, and observations for several days or weeks may be required.5 The goal of initial emergency care is to recognize lifethreatening injuries and to provide lifesaving and support measures until definitive care can be initiated.
. Treatment protocol for maxillofacial injuries
1. Stabilize patient
2. Identify injuries
3. Obtain radiographic studies and stereolithographic models
4. Initiate consultations (eg, psychiatry, physical therapy, speech therapy)
5. Initiate cultures/sensitivities (infectious disease consultations) 6. Unidertake serial de.bridement (days 3–10) to remove necrotic tissues
7. Stabilize hard tissue base to support soft tissue envelope and prevent scar contracture before primary reconstruction
8. Conduct comprehensive review of stereolithographic models and radiographs and determination of treatment goals
9. Replace missing soft tissue component (if necessary)
10. Perform primary reconstruction and fracture management
11. Incorporate aggressive physical/ occupational therapy
12. Perform secondary reconstruction (eg, implants, vestibuloplasty)
13. Perform tertiary reconstruction (eg, cosmetic issues, scar revisions)
Assessment of the Severity of Injury
The primary goal of triage is to prioritize victims according to the severity and urgency of their injuries and the availability of the required care. With regional trauma centers in modern trauma systems, the goal of triage is to rapidly and accurately identify patients with life threatening injuries and to treat those patients appropriately, while at the same time avoiding unnecessary transport of less severely injured patients (Figure 18- 1).6–8 Over the past three decades many scales and scoring systems have been developed as tools to predict outcomes based on several criteria.
Airway Maintenance with Cervical Spine Control
The highest priority in the initial assessment of the trauma patient is the establishment and maintenance of a patent airway. In the trauma patient, upper airway obstruction may be due to bleeding from oral or facial structures, aspiration of foreign materials, or regurgitation of stomach contents. Commonly, the upper airway is obstructed by the position of the tongue, especially in the unconscious patient (Figure 18-3). Initially a chin-lift or jaw-thrust procedure may position the tongue and open the airway. The chin-lift procedure is performed by placing the thumb over the incisal edges of the mandibular anterior teeth and wrapping the fingers tightly around the symphysis or the mandible. The chin is then lifted gently anteriorly and the mouth opened, if possible. This method should not hyperextend the neck.8 The other hand can be used to assist with access to the oral cavity, using the fingers in a sweeping motion to remove such things as debris, vomitus, blood, and dentures that may be responsible for the obstruction. A tonsillar suction tip is helpful to remove accumulations from the pharynx. Patients with facial injuries who may have basilar skull fractures or fractures of the cribriform plate may, with the routine use of a soft suction catheter or nasogastric tube, be compromised as these tubes may inadvertently be passed into the contents of the cranial vault during attempts at a pharyngeal suction. The jaw thrust procedure requires the placement of both hands along the ascending ramus of the mandible at the mandibular angle. The fingers are placed behind the inferior border of the angle, and the thumbs are placed over the teeth or chin. The mandible is then gently pulled forward with the fingers at the angle and rotated inferiorly with pressure from the thumbs. The elbows may be placed on the surface alongside the patient to assist with stability. The jawthrust procedure is the safest method of jaw manipulation in a patient with a suspected cervical injury. The jaw-thrust procedure does require two hands, and assistance must be available to clear the debris and other obstructions. After the jaw is opened, it may be possible to place a bite lock or large suction device to wedge the teeth open. An oral or nasal airway should be placed to elevate the base of the tongue and to maintain the patent airway. With any patient sustaining injuries above the clavicle, one should assume there may be a cervical spine injury and avoid hyperextension or hyperflexion of the patient’s neck during attempts to establish an airway. Excessive movement of the cervical spine can turn a fracture without neurologic damage into a fracture that causes paralysis. Maintenance of the cervical spine in the neutral position is best achieved with the use of a backboard, bindings, and purpose-built head immobilizers. The use of soft or semirigid collars allows, at best, only 50% stabilization of movement.22 Cervical spine injury should be assumed present and protected against until the patient can be stabilized and cervical injury can be ruled out during the secondary survey
.
Breathing
With establishment of an adequate airway, the pulmonary status must be evaluated. If the patient is breathing spontaneously— confirmed by feeling and listening for air movement at the nostrils and mouth— supplemental oxygen may be delivered by face mask. The exchange of air does not guarantee adequate ventilation. The chest wall of a patient with a pneumothorax, flail chest, or hemothorax may move but not ventilate effectively. Also, shallow breaths with minimal tidal volumes do not ventilate the lungs effectively. Very slow or rapid rates of respiration usually suggest poor ventilation. The patient’s status should be reevaluated constantly. If signs of adequate ventilation deteriorate, a secure airway should be placed (ideally an endotracheal tube) and assisted ventilation should be started. If the patient is not breathing after establishment of an airway, artificial ventilation should be provided with a bag-valve mask or a bag attached to an endotracheal tube. The patient who requires assisted positive pressure ventilation from an Ambu bag or ventilator must be carefully monitored if the chest status has not been completely evaluated. Changes in intrathoracic pressure may convert a simple pneumothorax into a tension pneumothorax. The chest should be exposed and inspected for obvious injuries and open wounds. There should be equal expansion of the chest wall without intercostal and supraclavicular muscle retractions during respiration. The rate of breathing should be evaluated for tachypnea or other abnormal breathing patterns. Signs of chest injury or impending hypoxia are frequently subtle and include an increased rate of breathing and a change in breathing pattern, frequently toward shallower respirations.7 The chest wall should also be inspected for bruising, flail chest, and bleeding, and the neck should be evaluated for evidence of tracheal deviation, subcutaneous emphysema, and distended jugular veins. The chest should be palpated for the presence of rib or sternal fractures, subcutaneous emphysema, and wounds. Auscultation of the chest may reveal a lack of breath sounds in an area, suggestive of inadequate ventilation. Distant heart sounds and distended neck veins are suggestive of cardiac tamponade. Arterial oxygen tension (PaO2) should be maintained between 70 and 100 mm Hg. Aside from airway obstruction, the causes of inadequate ventilation in the trauma victim result from altered chest wall mechanics. Open pneumothorax, flail chest, tension pneumothorax, and massive hemothorax are immediate lifethreatening conditions and should be quickly identified and treated.
Circulation
Following establishment of an adequate airway and breathing in the injured patient, the cardiovascular system of the patient must be assessed and control of baseline circulation to the tissues must be quickly restored. The most common cause of shock in the traumatized patient is hypovolemia caused by hemorrhage, either externally or internally into body cavities. Assessment of the degree of shock is important because inadequate tissue perfusion can cause irreversible damage to vital organs such as the brain or kidneys in a short time period. During the primary assessment a minimum of two large-bore (14–16 gauge) intravenous catheters should be placed peripherally if fluid resuscitation is required. At the time of placement of an intravenous catheter, blood should be drawn from the catheter to allow for typing, cross-matching, and baseline hematologic and chemical studies. If there is any doubt of adequate ventilation, arterial blood should be obtained for blood gas analysis. Tissue perfusion and oxygenation are dependent on cardiac output and are best initially evaluated by physical examination of skin perfusion, pulse rate, urinary output characteristics, and the mental status of the patient. Blood pressure levels are commonly used to measure cardiac output and to define hypovolemia, but in the emergency situation time does not permit blood pressure level measurement and the physical signs of hypovolemia are more sensitive to developing shock. The response of the blood pressure level to intravascular loss is nonlinear because compensatory mechanisms of increased cardiac rate and contractility, along with venous and arteriolar vasoconstriction, maintain the blood pressure in the young healthy adult during the first 15 to 20% of intravascular blood loss. After a blood loss of 20%, the blood pressure level may drop significantly. (In the elderly patient with less-efficient compensating mechanisms, the decline in blood pressure levels may begin to develop after a 10 to 15% blood loss.) The patient may arrest at an intravascular blood loss of 40%.29 Blood pressure level may be insensitive to the early signs of shock, and a patient’s blood pressure level may quickly drop following the initial assessment as the compensating mechanisms cao longer provide for the intravascular volume loss. Also, the usual baseline blood pressure level of the patient is often unknown. A patient who has a systolic pressure of 120 mm Hg but is normally hypertensive may have a significant loss, whereas a healthy young athlete may have a normal systolic pressure of 90 mm Hg and the blood loss might be assumed to be greater than it is. Skin perfusion is the most reliable indicator of poor tissue perfusion during the initial evaluation of the patient. The early physiologic compensation for volume loss is vasoconstriction of the vessels to the skin and muscles. The cutaneous capillary beds are one of the first areas to shut down in response to hypovolemia because of stimulus from the sympathetic nervous system and the adrenal gland through epinephrine and norepinephrine release. The release of the catecholamines causes sweating, and during palpation the skin may feel cool and damp. The lower extremities are usually first to be affected, and the first indication of intravascular loss may be paleness and coolness of the skin over the feet and kneecaps. A check of the capillary filling time by performing a blanch test gives an estimate of the amount of blood flowing to the capillary beds. In this test, pressure is placed on the fingernail, toenail, or hypothenar eminence of the hand (to evacuate blood from the capillary beds), followed by a quick release of the pressure. The time required for the blood to return to the capillary beds, represented by the restoration of normal tissue color, is usually < 2 seconds in the normovolemic patient. This indicates that the capillary beds are receiving adequate circulation.30 The rate and character of the pulse is a good measure of the cardiac rate. The pulse rate is a more sensitive measure of hypovolemia than is the blood pressure, but it is affected by other factors commonly associated with the trauma situation, such as the patient’s pain, excitement, and emotional response, resulting in tachycardia without underlying hypovolemia. However, in adults with tachycardia > 120 beats/min, hypovolemia should be expected and investigated further. Older patients generally are unable to exceed rates of 140 beats/min in a hypovolemic state, whereas younger patients may present rates of 160 to 180 beats/min with severe intravascular loss. In patients who have pacemakers, are taking heart-blocking medications such as propranolol or digoxin, or have conduction abnormalities within the heart, hypovolemic status may not be represented by increased pulse rates. The location of the pulse may give some indication of the cardiac output. Generally, if the radial pulse is palpable, the patient’s systolic blood pressure is > 80 mm Hg; if the femoral pulse is palpable, the patient’s systolic blood pressure is 70 mm Hg or higher; and if the carotid pulse is noted, the systolic blood pressure is > 60 mm Hg. Pulse rhythm and regularity may also provide clues to increasing hypovolemia and cardiac hypoxia. Cardiac dysrhythmias such as premature ventricular contractions or arterial fibrillations produce an irregular rate and rhythm, signaling the loss of compensating mechanisms maintaining myocardial oxygenation. Decreased intravascular volume is immediately reflected in decreased urinary output because the compensatory mechanisms of the body decrease blood flow to the kidneys in favor of blood flow to the heart and brain.Any patient with significant trauma should always have an indwelling urinary catheter inserted to monitor urine volume every 15 minutes.29 A minimally adequate urine output is 0.5 mL/kg/h, and fluid therapy should be initiated to maintain at least this level of urinary output. If the patient’s injuries include pelvic fractures or blunt trauma to the groin, a urinary catheter should not be placed until a urethrogram can be evaluated for urethral injury. If urethral injury is unlikely, the urinary catheter may be placed with minimal concern. Classic signs of urethral injury include blood at the meatus, scrotal hematoma, or a high-ridding boggy prostate on rectal examination. Alterations in the mental status of the trauma patient caused solely by hypovolemia are uncommon, except in the most progressive preterminal stages of intravascular fluid loss. Compensatory mechanisms maintain blood flow to the brain, and hypoperfusion to the brain does not develop until the systolic blood pressure falls below 60 mm Hg. The mental changes usually seen are agitation, confusion, uncooperativeness, anxiety, and irrationality. These alterations in mental status can also be seen in a patient with head trauma, spinal injury, drug or alcohol intoxication, hypoxia, or hypoglycemia. In the emergency situation these other causes of mental status changes should be investigated when hypovolemia is suspected in the agitated patient who has or possibly has suffered substantial blood loss.29 Hypovolemia caused by hemorrhage may commonly cause flat neck veins. Distended neck veins, however, suggest either tension pneumothorax or cardiac dysfunction. As discussed earlier, with tension pneumothorax an examination of the chest may reveal absent breath sounds and a hyperresonant chest. Cardiac dysfunction results from cardiac tamponade, myocardial contusion or infarction, or an air embolus. Cardiac tamponade presents a clinical picture that is similar to that of tension pneumothorax—distended neck veins, decreased cardiac output, and hypotension. Blunt or penetrating trauma may cause blood to accumulate in the pericardial sac. The blood in the pericardial sac results in inadequate cardiac filling during diastole, diminished cardiac output, and circulatory failure. Cardiac tamponade usually is associated with penetrating wounds to the chest that have injured the tissues of the heart. The classic Beck’s triad of decreased systolic blood pressure levels, distended neck veins, and muffled heart sounds may be observed. The expected distended neck veins caused by increased central venous pressure may be absent because of hypovolemia.
The neck veins, if distended, may become distended further during inspiration (Kussmaul’s sign), and the pulsus paradoxus (lowering of the systolic pressure by > 10 mm Hg oormal inspiration) may be accentuated or absent. Tension pneumothorax may mimic cardiac tamponade or, because of the nature of the penetrating injury, may develop at the same time as cardiac tamponade, thus presenting a confusing clinical presentation. Cardiac tamponade is initially managed by prompt pericardial aspiration through the subxiphoid route (Figure 18- 9). Because radiographs and physical examination are not helpful, a positive pericardial aspiration along with a history of chest trauma is frequently the only method of making a correct diagnosis. Because of the self-sealing qualities of the myocardium, aspiration of pericardial blood alone may temporarily relieve symptoms. All trauma patients with a positive pericardial aspiration require open thoracotomy and inspection of the heart. Pericardial aspiration may not be diagnostic or therapeutic if the blood in the pericardial sac has clotted, as occurs in 10% of patients with cardiac tamponade.29 If aspiration does not lead to diagnosis or improvement of the patient’s condition, only emergent thoracotomy can solve the problem. Pericardial aspiration through the subxiphoid route involves the insertion of a needle, preferably covered by a plastic catheter (angiocatheter), at 90° slightly to the left of the xiphoid process. The needle is inserted until it clears the sternal border and is then directed at 45° toward the left scapula to directly enter the pericardium. Suction is placed on the needle hub to identify by blood return when the needle has entered the pericardial sac. If the needle is properly placed, as little as 50 cc of blood from the pericardial sac should result in a marked improvement in the patient’s condition.
Neurologic Examination
Upon completion of the assessment of the cardiovascular system and control of any external hemorrhage, a brief neurologic evaluation is performed to establish the patient’s level of consciousness and pupillary size and reaction. This brief neurologic examination quickly identifies any severe CNS problems that require immediate intervention or additional diagnostic evaluation. A lack of consciousness with altered pupil reaction to light requires an immediate CT scan of the head and management with mannitol or fluid restrictions. Be aware of any medications that the patient may have received or drugs he or she may have taken that may affect the pupils. The Committee on Trauma of the American College of Surgeons recommends the use of the mnemonic AVPU.7,8 In this system, each letter describes a level of consciousness in relation to the patient’s response to external stimuli: alert, responds to vocal stimuli, responds to painful stimuli, and unresponsive. A more detailed quantitative neurologic examination is part of the secondary survey of the trauma patient. The primary survey establishes a baseline; if the patient’s neurologic condition varies from the primary to the secondary survey, a change in intracranial status may be present. A decrease in the level of consciousness may indicate decreased cerebral oxygenation or perfusion. The reactivity of the pupils to light provides a quick assessment of cerebral function. The pupils should react equally. Changes represent cerebral or optic nerve damage or changes in ICP. Further changes in pupil reactivity or levels of consciousness may be due to alterations in ventilation or oxygenation status. The most common causes of coma or depressed levels of consciousness are hypoxia, hypercarbia, and hypoperfusion of the brain.42 Depressed levels of consciousness and narrow pinpoint pupils may result after an opiate overdose. After an overdose with meperidine hydrochloride, the pupils may appear normal or dilated. In both cases, treatment requires the narcotic antagonist naloxone hydrochloride, 0.4 mg initially. Care should be taken to avoid a quick violent withdrawal phase in the opiate abuser; this is accompanied by profound distress, nausea, agitation, and muscle cramps. Both hypoglycemia and hyperglycemia can cause depressed levels of consciousness. If a quick blood glucose level cannot be obtained (and depending on other injuries), the patient can be given and immediate bolus of 25 g of glucose to manage critical hypoglycemia. A benefit of the glucose load is the hyperosmolar status that may, for a short time, reduce cerebral edema.
Exposure of the Patient
The patient should be completely disrobed so that all of the body can be visualized, palpated, and examined for injuries or bleeding sites. The clothing must be completely removed, even if the patient is secured to a spinal backboard. The easiest method is to cut the clothing down the midline of the torso, arms, and legs to facilitate the examination and assessment. Frequent careful reevaluation of the injured patient’s vital signs is important to monitor the patient’s ability to maintain an adequate airway, breathing, and circulation (Figure 18-15).
Secondary Assessment
The secondary assessment does not begin until the primary assessment has been completed and management of life-threatening conditions has begun.During the secondary assessment the patient’s vital signs and condition should be constantly monitored to evaluate the therapeutic interventions initiated during the primary assessment and to further assess the patient for any other life-threatening problems not evident during the primary survey. Changes in the patient’s vital signs, respiratory and circulatory status, and neurologic func- tions are expected in the first 12 hours.7 The secondary assessment includes a subjective and objective evaluation of the injured patient. A subjective assessment should include a brief interview with the patient, if possible. A brief health history can be useful, including medications; allergies; previous surgery; a history of the injury; and the location, duration, time frame, and intensity of the chief complaint.Obviously, the comatose patient cannot provide useful subjective information, but family members, bystanders, or other victims may provide some details. The objective assessment should involve inspection, palpation, percussion, and auscultation of the patient from head to toe. Each segment of the body (head and skull, chest, maxillofacial area and neck, spinal cord, abdomen, extremities, and neurologic condition) is evaluated to provide a baseline of the patient’s present condition. Special procedures such as peritoneal lavage, radiographic studies, and further blood studies may be done at this time.
Bilozetskyi Ivan
