14 Anaesthesia for maxillofacial trauma

Maxillofacial trauma is a vitally important area of trauma management. Four of five of our vital senses are contained within the face—sight, hearing, smell, and taste. Also, scarring and disfigurement to the face deeply affects our sense of self and our front to the world.

The aetiology of facial trauma has shifted in the more developed world towards assault being the most common cause (at around 36–41%), closely followed by road traffic accidents (RTAs)(25–32%). Other causes listed in order of frequency are falls (mainly in the extremes of age), sport, occupational injuries, and gunshot wounds^{1  ,2}.

As a group, 55–70% of patients with significant facial trauma will have other serious injuries^{2  ,3}. Looking at it the other way around, 30% of severely injured trauma patients also had maxillofacial trauma⁴. The most common isolated fracture reported is the nose which serves as the ‘crumple zone’ for the face when hit from the front (Figure 14.1). Those patients with injuries resulting from gunshots and RTAs had higher injury severity scores (ISS)^{2  ,3}.

One study from an American level 1 trauma centre looked at those patients with maxillofacial injuries and an ISS of over 12². They found that 43.7% of patients also had cerebral haematoma, with subdural being the most common. The second most commonly associated injury was pulmonary trauma, in particular contusions. Forty-two per cent of patients required intubation and 14% required a tracheostomy at some point. With regard to cervical spine injuries, 5% also had a cervical fracture and a quarter of these had neurological deficit. Looking at significant trauma injuries in Canada between 1992 and 1997³, 17% of patients with an ISS score of over 12 had maxillofacial injuries. The entire group had some kind of head injury with altered conscious level and 11% had a cervical spine injury.

Ophthalmic injury has been strongly linked to not wearing a seatbelt, increasing the risk from 2% up to 20% in one review⁵. Blindness is associated with 0.5–3% of midfacial fractures⁵. Upper and midfacial fractures are associated particularly with smell or taste disturbances. In one Italian series, about one-third of those who had treatment for upper third and mid third fractures suffered long-term disturbances of smell or taste⁶.

Major injuries of the head and neck should be seen initially by a full trauma team. Patients are assessed using the ABCs of trauma management with the airway as priority one, maintenance of cervical spine immobilization and oxygenation following on logically from this. Haemorrhage control of facial injuries has an immediate impact on the airway and oxygenation, and must therefore be dealt with as a matter of urgency.

The most senior help possible is needed with the airway management, as repeated attempts at intubation will worsen the situation. If maxillofacial or ear, nose, and throat (ENT) assistance is not a routine part of the trauma team, they should be summoned. Early ophthalmic review is also required, as rapid facial and periorbital swelling may mean that the eyes cannot be inspected for some time. Also, as previously alluded to, the risk of head injury is high, necessitating early neurosurgical input.

If unrestrained in a RTA or on a motor cycle, the patient is at risk from uncommon laryngeal/tracheal injuries. A high index of suspicion must be maintained. In a large US study between 1992 and 2004, only 37 of 16 465 patients with head, neck, or facial injuries were diagnosed with laryngeal fracture. However, 20 of these needed definitive airway control. Fourteen required tracheostomy, five endotracheal intubation, and one underwent cricothyroidotomy⁷. Laryngeal fracture is rare on account of the elastic nature of the larynx; however, it does become more calcified with age and may then fracture more readily.

Airway injuries can range from the life-threatening, such as a disrupted larynx which needs immediate intubation, to the patient with slight swelling and dysphagia who may only require observation. Observation is critical since maximal swelling will not occur for around 24–48 hours after injury. Only air bubbling through a wound and subcutaneous emphysema are pathognomonic signs for airway injury. Soft signs to watch for are stridor, respiratory distress, dysphagia, and hoarseness. The latter two can be signs of oesophageal or tracheal trauma.

The pathognomonic signs of vascular injury may be less reliable. These include haematoma, especially if there is expanding, active haemorrhage from the wound (arterial), bruit/thrill (arteriovenous fistula), pulse deficit, and distal ischaemia or neurological deficit. Current guidelines and the literature suggest four-vessel angiography with computerized tomography (CT) only if the patient has clinical signs and is haemodynamically stable. If unstable, then surgical exploration is indicated⁸.

Since a proportion of maxillofacial trauma patients have cervical spine injury (6.7%) and the spine may not have clearance prior to intubation, there is a need to protect the spine from unnecessary movement^{9  ,10}.

In an emergency situation, oral endotracheal intubation is the route of choice. A comparative study on cadavers¹¹ looking at the effects of manual inline stabilization and traction on oral intubation using different laryngoscope blades, the intubating laryngeal mask airway (ILMA), and the fibrescope (both oral and nasal) found that all airway interventions cause spinal movement, including facemask ventilation^{10  ,11}. Traction in the presence of cervical instability causes significant distraction that is damaging to the spinal cord and should be avoided. Manual inline stabilization and oral intubation gave conflicting results but there was less cervical movement with manual inline stabilization than with a rigid cervical collar in place. The presence of a cervical collar, tape, and sandbags also impeded optimal visualization of the laryngeal inlet, with 64% reporting Cormack and Lehane Class 3 and 4 laryngeal views. This compared to 22% reported Class 3 and 4 views when only manual inline stabilization was adopted¹². The ILMA and fibreoptic approaches, although causing significantly less movement, were more time-consuming¹³. Currently data is unavailable to differentiate between tracheostomy or cricothyroidotomy.

Clinicians should use the techniques with which they are most familiar and that are appropriate to the situation whilst keeping cervical movement to a minimum. Recent data indicate that direct laryngoscopy and intubation are unlikely to cause significant movement, but that manual inline stabilization may not fully immobilize injured segments¹⁴.

In one study, 22% of patients with significant facial trauma and higher Le Fort fractures required a tracheostomy for airway control, as did 10 out of 23 patients with Le Fort III injuries¹⁵. There has been some work looking at elective tracheostomy in patients with documented cervical spine injuries. An Israeli group followed up 38 such patients for an average of 18 months and found no deterioration following percutaneous tracheostomy. They stressed the importance of an experienced surgeon, avoiding neck extension but using a ‘gentle rostral traction of the larynx’ (towards the nose)¹⁶.

The use of the LMA in an emergency is debatable since it may worsen pharyngeal and laryngeal trauma, and does not protect the airway sufficiently from stomach contents and lower airway haemorrhage. As an emergency holding measure it probably has a place, particularly when facial disruption makes face mask ventilation difficult.

Transtracheal jet ventilation is another option for short-term oxygenation, but care must be taken to avoid hypercapnia and barotrauma, particularly if there is a concurrent intracranial injury.

A great deal of work is currently being carried out using new hand-held fibreoptic devices and we wait to see which will emerge as the most reliable and useful in these difficult scenarios (Chapter 4). However, work which conforms to the guidelines laid out in the excellent meta-analysis and review by R. Mihai of different airway aids is rare¹⁷. In a comparative unblinded study of the glidescope, the Pentax AWS, the Trueview EVO2, and the Macintosh laryngoscope, a small group of experienced anaesthetists used a mannequin to compare normal, rigid cervical spine, and tongue oedema scenarios. They found that the Pentax AWS performed best, probably owing to the side channel through which the endotracheal tube is placed before starting¹⁸.

Acute airway management in maxillofacial injuries can be challenging (Figure 14.2; see also Plate 5) and requires a coordinated team effort. Head injury and reduced consciousness will also dictate the need for direct airway control. The Glasgow Coma Score (GCS) should be regularly monitored since progressive airway obstruction is a risk. A GCS score of less than 8 indicates the need for intubation.

A patient with facial trauma may have other problems affecting the airway (Figure 14.3; see also Plate 6), e.g. blood, haematoma, foreign bodies, lost or broken teeth (see Figure 13.10), dentures, bony fragments, displaced bone, vomit, tongue injuries, and tissue oedema. Around a quarter of patients with Le Fort fractures present with either airway obstruction or decreased respiration requiring immediate airway control.

A strategy for airway control should be formulated promptly and all immediate clinical personnel involved in the patient’s care made aware of the intended procedure. A fibreoptic laryngoscope may be of little benefit in the presence of active haemorrhage. Summon senior anaesthetic and surgical help. Sufficient skilled anaesthetic assistance is mandatory for the induction of anaesthesia and maintaining cervical immobilization when necessary. It always helps to plan for the worst case scenario.

Antibiotics, antacids, and steroids are given, the last to reduce inflammation and fibrosis.

Most facial fractures will cause minor bleeding from the nose or mouth. In general terms, it is rare to have circulatory shock from maxillofacial injuries alone, and if significant resuscitation is ongoing then other sources of blood loss should be sought. Generally, this is a slow venous bleed and is controlled with a nasal pack or direct pressure to the wound. A steady flow of blood from the nose and mouth with profound cheek swelling is probably the result of a closed injury to the middle third. Occasionally, a major bleed will occur which needs careful packing of the posterior and anterior nasal spaces after airway control (Figures 14.4 and 14.5). Commonly this bleeding is from the end branches of the maxillary artery at the level of the pterygopalatine fossa and from the common carotid at the level of the skull base. Bleeding can often be seen as haematoma of the buccal mucosa. If packing is ineffective and the haemorrhage persists, then facial fractures should be repaired if possible. In the cardiovascularly unstable patient an alternative approach is to ligate the relevant arteries, although this can be inadequate as the face has a strong collateral circulation. Recently, blunt facial trauma and haemorrhage guidelines (Figure 14.6) recommend angiographic embolization when alternative methods have failed¹⁹.

Bleeding from the ear can be caused by a fracture at the base of the skull or a fracture of the condylar head which has been forced backwards and torn the external auditory meatus.

There are two main categories of penetrating facial trauma to consider: gunshot wounds and stab wounds. The higher the velocity of the gunshot, the greater the tissue damage and loss. There is also proportionately more swelling with high energy injury. The velocity depends on the type of weapon, torque of the bullet, and also the distance that the bullet has travelled. Transcervical gunshots cause very significant damage as might be expected. South African data suggests around half of gunshot victims have vascular injuries, of which most will need proactive airway management. A quarter will have spinal cord injuries, but only 9% had facial fractures. Laryngeal and pharyngeal injuries are very rare, constituting only 2%²⁰.

In contrast, stab wounds cause cleaner wounds with less tissue damage. A review of the management of penetrating neck injury looked at the issues surrounding those cases which did not have obvious signs of injury. In the absence of any neurological deficit, this group of patients may be better managed without a cervical collar which could obscure from view any expanding haematoma²¹. The generally accepted classification of injuries to the neck was described by Roon and Christiansen (Table 14.1)²². With no obvious signs of vascular injury and stable vital signs, even patients with penetrating trauma to Zone 2 can be investigated with CT angiography rather than surgical exploration as has been advocated in the past. The same recommendations apply to children with penetrating neck injuries²³.

Digestive tract injury is a rare occurrence but if undiagnosed beyond 24 hours has a much higher morbidity from mediastinitis²⁴. Symptoms and signs are vague but dysphagia, odynophagia (painful swallowing), haematemesis, central chest pain radiating to the back, and drooling should make the clinican alert to such a potentially serious injury²⁵. It should always be considered, even following minor penetrating trauma of the neck, and excluded with a swallowing/water-soluble dye test²⁶.

Neurological deficits should be monitored with the AVPU scale (A, alert; V, responds to vocal stimuli; P, responds only to painful stimuli; U, unresponsive to all stimuli), together with the pupillary reactions. The GCS should also be measured at frequent intervals.

Damage to the eye and the neuronal pathways can occur directly or from external compression. Periorbital oedema may limit eye examination, but every effort should be made to examine the visual acuity, visual fields, pupillary size, and reflexes. The eyes should be inspected for conjunctival or fundal haemorrhage, penetrating injury, lens dislocation, and ocular entrapment. The latter will be evident by inability to move the eyes through a full range of normal movements.

If there are any concerns regarding ocular damage, the ophthalmologist should be contacted promptly since early diagnosis correlates favourably with the preservation of visual accuity. Serial examination of function is vitally important. A progressive loss of vision indicates urgent surgical exploration and decompression of the optic nerve. In addition to surgical intervention, the anti-inflammatory effects of high dose steroids may be necessary to preserve the function of the optic nerve, the most common cause of visual loss²⁷.

A dural tear is possible with all midface and above fractures. It is reported to occur in 4.6% of patients with maxillofacial trauma²⁸ at the cribriform plate and can present with cerebrospinal fluid (CSF) rhinorrhoea. Fracture of the temporal bone in the middle cranial fossa may result in otorrhoea that can track along the Eustachian tube to give ‘paradoxical’ rhinorrhoea. Soft tissue oedema may prevent the leakage of CSF which can then become apparent after a few days when the swelling subsides.

Definitive diagnosis can be difficult. CSF classically causes tram lines on the face or a halo effect on bedding. This is due to blood coagulating and CSF continuing to flow. However, a mix of blood and tears or saliva can give the same effect. Measurement of beta-2 transferrin is the most sensitive test as it is only found in the CSF, perilymph, and vitreous humor. Fine cut CT scans may show CSF fistulae, but MRI scanning is more accurate and is the preferred modality²⁸.

Most cases of CSF leakage stop spontaneously and the majority after the fractures have been fixed. Persistent CSF leaks should be referred to the neurosurgical team and are usually treated by lumbar drainage followed by surgery if necessary.

Antibiotic prophylaxis is usually given, but good CSF penetration is unreliable and there is growing concern regarding bacterial resistance. Since the main risk is meningitis, many clinicians are reluctant to withhold antibiotic treatment. One retrospective analysis of 160 patients with traumatic CSF fistulae showed a 30.6% incidence of meningitis if untreated, 4% of which were fatal. Formal dural repair reduced the incidence of meningitis to 2%²⁹.

The implications for the anaesthetist are unclear. Certainly passage of an endotracheal tube into the cranium has occurred (although there is only one case following facial trauma reported in the literature) and been associated with a fatal outcome³⁰. As regards facial injuries, there is no real need to consider the nasal route for intubation in the acute situation. However, for definitive surgery to have good results, nasal intubation is necessary for optimal intraoperative occlusion. Although the studies have limitations, there is no evidence that nasal intubation following facial trauma increases the risk of CSF contamination over and above that which has already occurred^{31  ,32}. Alternative strategies for endotracheal intubation in facial trauma are discussed further below.

With the exception of mobile fracture of the mandible, even extensive facial trauma does not cause a large amount of pain. Simple analgesics such as non-steroidal anti-inflammatory drugs (NSAIDs) with paracetamol and/or codeine are usually sufficient. Acute pain often subsides with the fixation of the fractures.

Facial fractures can be unilateral or bilateral and follow specific lines of structural weakness and are described in Chapter 13. The timing of definitive repair of facial injuries will depend on prioritization in the presence of other significant injuries. Ideally, eye injuries should be treated first followed by soft tissue toilet and suture (within 12 hours). Most fractures will be fixed via other incisions, so the repair to the soft tissues should be considered as definitive. Mandibular fractures are very painful and inhibit swallowing, and should be fixed within 24–48 hours. Other fractures, in particular midfacial and orbital, may need CT scanning to assess them adequately and should ideally be fixed by 7–10 days after injury. Delays beyond this time increase the likelihood of suboptimal fixation and misalignment.

Definitive repair of maxillofacial fractures usually occurs through intraoral, subconjunctival, or scalp incisions. In complex cases, 3D imaging is used to allow intraoperative navigation-guided fixation. Mandibular fractures are generally more painful and often prevent swallowing and do not usually necessitate CT images.

Of particular interest to the anaesthetist is the mechanism of the trauma and the possibility of a head, cervical spine, or other injury. A history of drug or alcohol abuse should be sought as these conditions are often related to the circumstances leading up to the injury.

Assessment of the airway should include the normal inspection for deformity, swelling, dental damage or loss, nasal patency, mouth opening, Mallampati score, and neck movements. For fractures within 10–14 days, limited mouth opening is usually due to trismus caused by pain and will disappear after induction. There are, however, a few situations when inability to open the mouth may not be due to pain and trismus alone. Late presentation of an infected fracture with submasseteric pus and also rarely central dislocation of a temporomandibular joint (TMJ) into the temporal fossa, a fractured zygoma which obstructs the coronoid process of the mandible, can give rise to serious limitation of mouth opening which persists even after the induction of anaesthesia and therapeutic neuromuscular paralysis. These latter patients need very careful preoperative evaluation (Chapter 4).

Before commencing anaesthetic induction, it is essential to discuss the operative plan with the maxillofacial surgeon. If in doubt, ask the surgeon if there is any mechanical reason why the mouth might not open fully following anaesthesia. In most cases of midfacial fractures, temporary dental intraoperative occlusion is required and an oral tube will prevent this unless there is a sufficient gap in the patient’s dentition. Some complex injuries, however, may require the application of intraoperative intermaxillary fixation (IMF) which will prevent access to the oral cavity postoperatively, with major implications for the anaesthetist and patient. For zygomatic and orbital surgery, a south-facing Ring-Adair-Elwyn (RAE) tube is suitable. The latter often involves surgical access to the superior orbital fractures via a coronal flap which allows the scalp to be reflected down over the face (Figure 14.7; see also Plate 7). Panfacial fractures involve both the structural bones and smaller bones of the nasal complex, which means that access to the nose as well as occlusion is needed. If the proposed surgery cannot be carried out with an oral endotracheal tube, the alternative options are formal tracheostomy (Chapter 5), a nasal fibreoptic intubation under direct vision (Chapter 4), or a submental intubation (Table 14.2).

Submental intubation involves passing the endotracheal tube through a surgical incision in the floor of the mouth (Figure 14.8). Since it was first described in 1986 by Hernandez Altemir³³, it has been successfully used in the anaesthetic management of both trauma and elective orthognathic patients with a low complication rate^{34  –36}. The literature reports two abscesses in the floor of the mouth following submental intubation but both resolved with local conservative treatment³⁵. In another report two patients subsequently required a tracheostomy for respiratory failure. Interestingly, 14 patients of this series of 25 were ventilated postoperatively for over 24 hours with no problems³⁶.

There are a number of practical points to consider with regard to submental intubation. Owing to the acute angle from the submental insertion of the tube to the trachea, an armoured tube is recommended to prevent kinking. The endotracheal tube associated with the ILMA is the easiest to use for submental intubation as the tube is reinforced and has a detachable connector. Once exteriorized, the tube is secured at the neck by a surgical suture. Movements of the neck will have an exaggerated effect on the distal end of the tube in the trachea, and both accidental extubation and bronchial intubation have been reported. Positioning of the tube at a midway point between the carina and vocal cords is therefore important. In complex cases the position of the endotracheal tube may need to be changed intraoperatively.

For maintenance of anaesthesia a total intravenous technique using propofol and remifentanil has a number of advantages. It allows rapid awakening with early return of glottic reflexes, immediate assessment of conscious level, and cooperation with eyesight testing after zygomatic and orbital floor work. It is also less emetogenic than the volatile agents. Deliberate hypotension is of limited benefit in the majority of cases and is contraindicated if there has been a concomitant head injury. The general principles for control of intracranial pressure (ICP) suffice (head-up tilt, normocapnia, and rehydration).

Surgical manipulation of the mid third of the face can be associated with a severe reflex bradycardia. Levering, in an attempt to reduce a depressed zygomatic arch fracture, is of particular note in this respect.

Once fixed many facial fractures are often associated with only moderate pain so large doses of opiates are unnecessary. Intravenous NSAID administration and intravenous tramadol is a good alternative or addition since it causes less sedation and respiratory depression than morphine. Mandibular fractures and orbital repairs which go behind the eye are, however, exceptions and often require opiate analgesia. The use of local anaesthesia by the surgeon is helpful in this respect. A throat pack is used to prevent accumulation of blood in the oropharynx. Although endotracheal tubes are cuffed seepage of blood into the lungs can occur and cause bronchial blockage. It is important that mechanisms are in place to prevent accidental pack retention. To this end it is recommended that the pack is part of the surgical pack count and its insertion and removal recorded separately.

Extubation should be considered as carefully as intubation. There are a number of patients who will need to stay ventilated for neurosurgical considerations or other injuries received. If the patient is to be extubated, the degree of oedema and airway compromise must be carefully evaluated; further swelling can occur up to 48 hours after the initial injury. Patients with hyoid fractures have a very high risk of airway obstruction owing to secondary oedema and should be left intubated for at least 24 hours before evaluating the degree of swelling.

The position of any residual nasal packs must be checked since they can migrate down into the pharynx and cause considerable airway irritation and, occasionally, complete airway obstruction (Chapter 12). Oropharyngeal suction to remove any residual blood clots, secretions and throat pack is mandatory prior to extubation.

Peroperative remifentanil has found widespread acceptance for oral and maxillofacial anaesthesia and has undoubtedly made difficult extubation easier³⁷. Once the remifentanil has been discontinued, the patient will reliably wake up, obey commands, and tolerate extubation smoothly under its residual narcotization. All Le Fort II or III fractures are at risk postoperatively from further swelling or haemorrhage which may compromise the airway and will require specialist nursing care, preferably on a high dependency unit or similar facility for 12–24 hours postoperatively.

In children, 78% of dog bites received are on the face, in contrast to adults which are mainly on the limbs. In one year there were 902 children under the age of 9 years admitted to hospital in England because of dog bites and there continue to be occasional deaths³⁸. Because of dog's high masticatory forces in the order of 50–100 kg/cm², there is often severe tissue contusion with large areas of devitalized tissue. In contrast, domestic cat bites tend to have a deeper puncture wound with a very high risk for deep-sited infection. The main preoccupation for animal bites is the prevention of infection. Consequently, rapid cleansing is needed with high intensity flushing. This should be carried out as a matter or urgency with minimal delay. Routine simple anaesthetic technique is used and intravenous antibiotics are indicated if infection occurs³⁸.

Gunshot wounds to the face require thorough cleansing. The absorbed energy of high velocity bullets causes massive tissue necrosis; however, owing to the excellent blood supply to facial tissues a surprising amount can survive. CT scanning, plus or minus angiography, is the most useful investigation for evaluation of this type of injury. Residual metal fragments can, however, cause some distortion of the image. Gunshot wounds must be cleansed as for dog bites above, debrided as little as possible, and then simultaneous soft tissue revision and closure is advised^{39  ,40}.

The patient with maxillofacial trauma can be a considerable challenge to the anaesthetist. With minimal notice, they can be called upon to secure an airway acutely following oral and maxillofacial trauma. The situation often requires specialized skills and equipment. A systematic and ordered approach to what can be a frightening situation is essential.