13 Maxillofacial trauma
Facial injury can occur in isolation or in combination with injuries elsewhere. Regardless of the site of injury, there are local and systemic effects. Trauma causes physical injury to soft or hard tissues and this gives rise to an inflammatory response, resulting in pain, tenderness, swelling and reduced function. Loss of physical integrity at the sites of injury is also common: the skin may be abraded, lacerated or lost and bones and teeth may be stressed to the extent that they fracture or dislocate. Indirect soft-tissue injury is rare, but can occur through traction to the skin due to blunt trauma and tearing at distant sites. Indirect trauma is a more common cause of fracture: for example, a blow to the mandibular symphysis can cause a distant subcondylar fracture.
As well as the inflammatory response and local effects of trauma, systemic effects involving biological and psychological stress reactions occur. Biological stress reactions include release of endogenous catecholamines (the ‘fight, flight and fright reaction’) and associated psychological stress reactions often comprise feelings of shock, fear, an increased sense of vulnerability and sometimes denial (inability or failure to appreciate that the injury has actually occurred). Metabolic changes are similar to those which follow administration of high doses of steroids. Oxygen consumption, carbon dioxide production and protein breakdown increase.
An understanding of the cause of injury is important for several reasons. It helps to focus on the need for injury prevention; it may help identify typical patterns of injury (e.g. the blow to the symphysis associated with a condylar fracture or head injury), and it may raise awareness of the risk of future injuries (for example, in cases of domestic violence). There are many unique features of injuries of the face because it is responsible for the senses of sight, smell, taste and hearing. In addition, eating, drinking, speech and communication through facial expression depend on the integrity of maxillofacial structures. Disruption of the maxillofacial skeleton can hazard the airway.
In those with maxillofacial injuries it is also necessary to consider the possibility that there may be injury to the base of the skull, cranial vault and brain, the cervical spine and the upper aerodigestive tract. Indirect effects on the upper aerodigestive tract may include airway obstruction or partial obstruction because of blood, saliva and fragments of teeth or bones. Airbag injuries may affect the neck and face together. The presence and extent of brain injuries influences the risk of distant effects on the aerodigestive tract where, for example, coma may predispose to the inhalation of fragments of teeth and blood.
There is some evidence that the face acts as a ‘crumple zone’ (in the same way as the front of an automobile absorbs impact which might otherwise be transmitted to the passenger compartment) and therefore has a protective effect in terms of brain injury. Facial injuries and brain injuries are often seen together simply because they share the same anatomical region. Overall, the more serious the facial injury, the more likely is brain injury.
The causes of maxillofacial injury reflect the culture in which it is sustained. The most frequent cause of serious maxillofacial injury in the developed world in the past century has been the motor vehicle, the only exception being epidemics of injury sustained in two world wars. Overall, incidence of maxillofacial injuries has reflected death rates on the roads such that, for example in the UK, incidence reached a peak in the 1960s and the 1970s and has been falling since. Violence has become a more common cause of maxillofacial fracture, on both sides of the Atlantic, since the late 1960s.
The causes of historical increase in road trauma include progressive industrialization and expansion of the motor industry leading to steadily increasing numbers of vehicles, lack of focus on safety during the first 60 years of automobile and motorcycle development and lack of investment in motorways until the 1970s. Determined efforts to reduce risks have led to drink-drive and seat-belt legislation, construction of safer roads and increased safety of the vehicles themselves. Increases in violence have been caused by numerous factors, including low levels of social control of young people in families and in the workplace, unemployment, the development of a drug culture, decline in real alcohol prices and more leisure time. Surveys of maxillofacial injuries in Middle-Eastern countries demonstrate much lower incidence of injury overall and a lower incidence of alcohol-related trauma.
The most effective approach to prevention of maxillofacial injury has been attention to the particular circumstances of injuries in particular environments (secondary prevention). Thus, wearing a cycle helmet has been shown to prevent upper facial injury, gum shields prevent many sports injuries and toughened or plastic glassware reduces the risk of facial injury in assault in licensed premises. Educational interventions, for example in schools, have had much less effect. Preschool education together with early family support (primary prevention) has been shown to reduce later assault as well as other forms of delinquency such as truanting, drug abuse and early pregnancy.
The management of the acutely injured patient in the accident and emergency department depends on organized, well-practised teamwork, under the direction of a team leader. However, whenever a seriously injured, perhaps unconscious patient is encountered, the presence of a cervical spine injury should be assumed until proved not to exist and neck movements should therefore be kept to a minimum. Obvious bleeding should be controlled using pressure, wire ligatures around teeth adjacent to fractures, ligature of vessels (such as the facial artery) and inserting ribbon gauze packs into, for example, intraoral lacerations of the sulci. The airway must be established and maintained by altering posture, by aspiration and, if necessary, by means of endotracheal intubation. Tongue control, by means of oropharyngeal or nasopharyngeal tube airways, may be useful. Where there is total upper airway obstruction, a laryngotomy through the cricothyroid membrane may be necessary. Chest radiography and analysis of blood loss are necessary early in the case of chest emergencies. Ventilation to keep the arterial pO2 above 10 kPa and pCO2 below 5.5 kPa can be achieved by a bag valve mask. To support the circulation, the insertion of the largest possible cannula into an antecubital vein is usually the best option for intravenous infusion.
This focus on Airway, Breathing, Circulation, in this order, together with the assessment of cervical spine integrity, disability and neurological state, comprise the primary survey and resuscitation phases, which are key to life support for trauma patients. This facilitates the logical progression to secondary injury surveys and the definitive care phase.
Accurate verbatim accounts of injury are important because this medical evidence may be of great relevance to investigations by the police, insurance companies and researchers. Although it is not usually necessary to record the cause of injury in detail, a short summary is always helpful. In relation to assault, for example, this should include the type of weapon, how many assailants were reportedly involved and where precisely the assault took place. For car occupants, seat-belt wearing and position in the car should be recorded. An essential part of the history relates to tetanus prophylaxis: the year of the most recent ‘booster’ should be established and prophylaxis administered if necessary.
Dental surgeons are often asked to see the injured person after their general condition has been stabilized. Occasionally this is not the case, however, and a dental practitioner may be the first to the scene of a serious accident or assault. If injuries are life-threatening, the history should be dispensed with until airway, cervical spine, breathing and circulation have been stabilized.
It is often said that records about alcohol are important, but at the initial consultation it can be extremely difficult without objective measurement to assess its effects. It is a mistake to blame people for their injuries just because they have been drinking. Nevertheless, if alcohol abuse is to be investigated then breath analysis is appropriate for acute intoxication. Pure ethyl alcohol, reflecting its volatile nature, may be smelt on the breath, but almost all alcoholic drinks contain other volatile components (congeners), which make smell alone an unreliable measure of alcohol consumption.
First described by two Glasgow neuroscientists, the Glasgow Coma Scale (GCS) is an internationally recognized method for measuring coma. It cannot discriminate between causes of coma, such as brain injury or alcohol intoxication, but it provides an excellent means of assessing the need for hospital admission and recovery (Table 13.1).
|Best motor response:|
|Best verbal response:|
Scores for the three components can be added together (< 8 is defined as coma; maximum score = 15) or listed separately.
Very often, by the time a dental practitioner is called to see an injured person, some radiographs have already been obtained. Looking at these before seeing the patient is a mistake. An enormous amount can be missed from focusing first on radiographs. For example, they do not show soft-tissue injuries and superimposition often makes primary diagnosis of mandibular, symphyseal and cranial base fractures difficult or impossible. Much information can be gained simply by observation of the patient. Although dental practitioners will usually not be responsible for managing injuries outside the maxillofacial region, examination should always start with an overall assessment of injuries.
Pay particular attention to signs of bleeding or other discharge from the ears, eyes, nose and mouth. In seriously injured patients there may be leakage of cerebrospinal fluid from the ears or nose. Look for signs of impact, including on the scalp. Abrasions (Fig. 13.1) or haematomas often signal the sites of underlying bone injury. There is often little swelling in the immediate aftermath of injury. However, within 6 hours mandibular angle fractures, for example, are often associated with swelling over the angle (Fig. 13.1) and subcondylar fractures with preauricular swelling.
Always take a systematic approach to the examination of the maxillofacial region. As with occipitomental radiographs, start superiorly and work down the face in a series of arcs to reduce the chances of an injury being missed.
Stand behind and above the patient when assessing facial asymmetry, particularly in relation to suspected zygomatic fractures. In this position place an index finger on the maximum convexity of the zygoma on both sides equidistant from the tip of the nose. Then compare the overlap of the index fingers with the supraorbital ridges.
Mobility of the middle third of the face, such as that brought about by Le Fort I, Le Fort II and Le Fort III pattern fractures (Fig. 13.2) is best assessed by placing the patient’s head securely against a head rest, grasping the upper teeth and alveolus and moving them gently, but purposefully, laterally, superiorly and anteriorly. Simultaneous palpation of the nasal bones has often been advocated but this can give rise to false-positive findings because of the mobility of the scalp and skin in this region. A ‘cracked cup’ sound when the upper teeth are percussed can be diagnostic of a Le Fort pattern fracture.