Key points

  • Oral and maxillo-facial cases present frequently on the emergency operating list and can pose significant challenges for the anaesthetic team.

  • Forty per cent of cases reported to the recent NAP 4 audit were head and neck pathology.

  • Correct management requires early recognition and knowledge of anatomy and path of spread of infections.

  • Facial and neck trauma can present specific challenges for the anaesthetist.

  • Careful assessment and planning, effective communication, early senior involvement and appropriate back up plans are paramount for a successful outcome.

Maxillo-facial cases frequently present for emergency surgery and are commonly infective or traumatic in nature. These are usually first assessed by junior members of the anaesthetic and surgical teams. A thorough understanding of the potential for complications and the need for a ‘whole strategy’1 approach in airway management is essential in achieving a successful outcome.

Head and neck infections

Despite advances in microbiology and antibiotic therapy, the treatment of head and neck infection often requires surgery. It can present with life-threatening complications such as airway obstruction, mediastinal spread, and cavernous sinus thrombosis, all of which have increased morbidity and mortality.

Pathophysiology

Odontogenic- or dental-related infections begin with decay and progress to pulpitis, which is inflammation of the nerve chamber in the centre of the tooth. Infection then spreads into the bone and causes perforation of the bone cortex into the subperiosteal region. Fascial planes of the head and neck are virtual spaces, bounded by muscle attachments and bone. The muscle attachments and fascial planes will govern in which direction the infection spreads to the soft tissue spaces. Knowledge of the orofacial musculature is needed to predict the path of infection. The commonly affected fascial spaces are illustrated in Figures 1 and 2. Infection can spread from these into the infra-temporal fossa, sub-temporalis, and parapharyngeal spaces. This describes the local or direct spread.

Fig 1

Axial section of right mandible showing potential paths of spread of infection from a carious wisdom tooth.

Fig 1

Axial section of right mandible showing potential paths of spread of infection from a carious wisdom tooth.

Fig 2

Coronal section of right mandible showing potential paths of spread of infection from a carious wisdom tooth.

Fig 2

Coronal section of right mandible showing potential paths of spread of infection from a carious wisdom tooth.

The spread from the pre-maxillary region (soft tissue anterior to the maxilla containing the canine and part of the buccal space) can progress to orbital cellulitis. If left unchecked, this can lead to cavernous sinus thrombosis. A parapharyngeal abscess often has little clinical signs until the airway is compromised, as the swelling is intra-oral or parapharyngeal. A frequent culprit is a wisdom tooth which also causes submasseteric inflammation and trismus. Examination of the pharynx is almost impossible in the presence of severe trismus and patients are often falsely downgraded in priority, due to lack of visible swelling.

Complications of spread to cervical fascial planes include airway obstruction, mediastinitis, and pulmonary aspiration of pus either through spontaneous rupture or iatrogenic rupture during attempts at intubation.

The haematogenous spread can lead to thrombophlebitis, bacteraemia, prosthetic valve, or joint involvement and systemic sepsis. The spread of infection is affected by compromised host defences such as diabetes mellitus, malignancy, or immunosuppression.

Preoperative considerations for dental abscess surgery

All patients require an appropriate and adequate preoperative assessment to define the extent of disease progression, in particular, looking for indicators of potential airway compromise, anticipated difficulties in airway management, and significant comorbidities. A history of altered speech, odynophagia, rapidly worsening swelling, and severe trismus can signify partial airway obstruction. Stridor and dysphagia are often late signs and stridor may be absent when at rest.

Careful assessment of the airway is needed using routine bedside techniques such as Mallampati score, interdental distance, and protusion of the mandible and should include a detailed examination of the neck. The lack of tongue protrusion is a very sensitive indicator of sublingual involvement and a good indicator of impending airway compromise. Mouth opening can be limited by trismus. Application of the assessment findings, to help anticipate where difficulties might be encountered, for example facemask ventilation, direct tracheal access, insertion of supraglottic airway devices, or emergency surgical airway access, will assist the planning and decision-making processes (see Table 1). Senior anaesthetist and surgeon involvement should start early. Preoperative imaging may have facilitated surgical diagnosis and operative strategy and should be reviewed by the anaesthetist for further evaluation of the airway. Flexible nasendoscopy should also be considered.

Table 1

Key considerations to assist in decision-making in the choice of the anaesthetic technique

These cases can be challenging and each one should be taken on its own evaluation and often requires experienced help
 
 
Preoperative findings Techniques
 
Considerations Caution Outcome  
Assessment of airway Conventional induction of anaesthesia then establish an airway I.v. + muscle relaxation Do I anticipate any difficulty with facemask ventilation? If difficulty is not anticipated and airway adjuncts can be used, proceed with caution. Patient asleep with definitive airway  
Does the mouth open adequately for me to use adjuncts?  
You may require:  
Oral/nasal airways, LM airway  
Rapid sequence induction if aspiration risk Do I anticipate any difficulty with intubation? Alternative laryngoscopes  
Intubating laryngeal mask  
Have I assessed all the swelling? Asleep fibreoptic  
Could this be subtle airway obstruction? Always plan for unanticipated difficulty, failed intubation, and CICV situations  
Inhalation Children May take longer in obstructed airway. Aspiration risk, agitation, laryngospasm  
Uncooperative adults  
Awake fibreoptic intubation ±Local anaesthesia Difficult airway management anticipated (either face mask ventilation or intubation) May be difficult if moderate blood in airway. Beware advanced airway obstruction  
±Sedation  
Poor mouth opening Plan for tracheostomy in case of failure  
Tracheostomy under local anaesthesia  Are there already signs of airway obstruction? May be difficult if swelling significant in anterior neck  
Failed awake FOI Does the benefit outweigh the risk of alternative techniques?  
These cases can be challenging and each one should be taken on its own evaluation and often requires experienced help
 
 
Preoperative findings Techniques
 
Considerations Caution Outcome  
Assessment of airway Conventional induction of anaesthesia then establish an airway I.v. + muscle relaxation Do I anticipate any difficulty with facemask ventilation? If difficulty is not anticipated and airway adjuncts can be used, proceed with caution. Patient asleep with definitive airway  
Does the mouth open adequately for me to use adjuncts?  
You may require:  
Oral/nasal airways, LM airway  
Rapid sequence induction if aspiration risk Do I anticipate any difficulty with intubation? Alternative laryngoscopes  
Intubating laryngeal mask  
Have I assessed all the swelling? Asleep fibreoptic  
Could this be subtle airway obstruction? Always plan for unanticipated difficulty, failed intubation, and CICV situations  
Inhalation Children May take longer in obstructed airway. Aspiration risk, agitation, laryngospasm  
Uncooperative adults  
Awake fibreoptic intubation ±Local anaesthesia Difficult airway management anticipated (either face mask ventilation or intubation) May be difficult if moderate blood in airway. Beware advanced airway obstruction  
±Sedation  
Poor mouth opening Plan for tracheostomy in case of failure  
Tracheostomy under local anaesthesia  Are there already signs of airway obstruction? May be difficult if swelling significant in anterior neck  
Failed awake FOI Does the benefit outweigh the risk of alternative techniques?  

Anaesthetic technique

The choice of anaesthetic technique will be influenced by the airway evaluation, the skills of the anaesthetist and surgeon, and the available equipment. Conventional i.v. induction of general anaesthesia with muscle relaxation, inhalation route without muscle relaxation, insertion of trans-tracheal catheter under local anaesthesia before induction, awake fibreoptic intubation or tracheostomy under local anaesthesia have been techniques described in the literature.2 Adequate pre-oxygenation, i.v. access, and monitoring are paramount irrespective of the technique used.

Trismus secondary to infection might not improve with induction of anaesthesia.3 In cases where mouth opening is limited and swelling is confined to the oral cavity, there should be a low threshold for the use of awake nasal fibreoptic intubation. In the recently published NAP 4 report, failure to consider awake fibreoptic intubation as the primary airway technique led to direct harm in a proportion of reported patients. The avoidance of muscle relaxation when a difficult laryngoscopy is also anticipated, by using either a gaseous induction or a TIVA technique led to a feeling of false reassurance and contributed to adverse outcome in some cases.2 This, however, should be balanced against those cases where these techniques were used successfully and so, were not included in the project. It should be recognized that all primary techniques may fail and that clear rescue plans are in place before commencing anaesthesia. The location of anaesthetic management also needs consideration. The NAP 4 report recommends the anaesthetic management of any case which may involve surgical tracheostomy as a rescue technique should start in the operating theatre.2

Once a secure airway is established, anaesthesia can be maintained by either gaseous or i.v. routes. A saline-soaked throat pack is placed in the oropharynx, if possible, to absorb pus, secretions, and blood. Antibiotics are given according to local microbiology guidance. I.v. dexamethasone may also be required.

The operating table may need to be rotated to 90° or 180° with regards to the anaesthetic machine. Pain relief can be provided by paracetamol, non-steroidal anti-inflammatory drugs, intra- oral local anaesthesia, and long acting opioids.

Postoperative management

The decision to extubate post-surgery should be taken on a case-by-case basis and after discussion with the surgeon. For patients with significant swelling and stridor at presentation, it may be necessary to keep them sedated and ventilated until extubation becomes safe to do so. Some patients are likely to develop further postoperative swelling, particularly those with Ludwig's angina or parapharyngeal involvement.

The Difficult Airway Society is currently drafting guidelines for extubation. Anticipating, planning, and preparing for what could be an equally dangerous time of anaesthesia should include checking for a ‘cuff down’ leak, having airway equipment for re-intubation on standby, appropriate anaesthetic drugs drawn up in the required doses, and a management strategy in case extubation fails. The surgical team should remain in the operating theatre until successful extubation has been established. A period of observation in theatre should follow before transfer to recovery.

Special considerations

Ludwig's angina

Ludwig's angina is a life-threatening cellulitis of the floor of the mouth involving both submandibular and sublingual spaces, bilaterally. It was first described in 1836 by Wilhelm Friedrich von Ludwig. A good predictor of sublingual involvement is the inability of the patient to protrude the tongue. This is related to the anatomical shape of the genioglossus muscle which is c-shaped. The concavity of the ‘c’ produces the sublingual space. When this is full (oedema or pus), the muscle cannot fold over itself, as happens in tongue protrusion.

Surgical tracheostomy is often difficult and occasionally life threatening due to the involvement of the neck and pre-tracheal tissues. Incising through the pre-tracheal fascia and exposing the pre-vertebral tissues to pathogens risks the spread of infection into the mediastinum. Mediastinitis, despite modern healthcare, still carries significant mortality.4

Facial trauma

The face is a complex apparatus, giving us the ability to eat, speak, smell, hear, see, and interact socially. Facial injuries can be life threatening, by compromising the airway and causing significant blood loss.

Epidemiology

The most common causes of facial injuries in the UK are5: In a BAOMS survey of the UK facial injuries in 1997, the male-to-female ratio was 2:1 overall. The mean age was 25.3 years.6 Facial fractures have associated soft tissue injuries and dental injuries. Traumatic brain injury occurs in 15–48% of patients with maxillo-facial trauma.7 The incidence of cranio–maxillo–facial injuries initially decreased after basic road safety measures (seat belts, motor cycle helmets), but has increased again due to interpersonal violence.5

  • interpersonal violence (52%),

  • road traffic accidents (16%),

  • sports injuries (19%),

  • falls (11%),

  • industrial accidents (2%).

Anatomical considerations

The facial skeleton is composed of many bones inter-digitating with each other at suture lines. It is designed to perform several functions but in the context of trauma, they act as a crumple zone to evenly distribute energy transferred to the face whilst minimizing damage occurring to the skull and brain. There are natural points of weakness in the facial skeleton as well as areas of very strong dense bone called buttresses (Fig. 3). Facial fractures occur in characteristic points where the bones are weakest, and when the buttresses break, it is less usual for the break to be comminuted. Comminution implies greater energy transfer. There are further points of weakness where the facial bones are penetrated by vital structures forming ‘holes’ in the bony cortex. An example of this is the infra-orbital foramen carrying branches of maxillary nerve (second branch of trigeminal nerve, V2) and infra-orbital vessels.

Fig 3

Facial buttresses (with kind permission from Springer Science+Business Media).10

Fig 3

Facial buttresses (with kind permission from Springer Science+Business Media).10

The tongue is tethered forward to the mandible by the paired genioglossi muscles that insert into the genial tubercles on the lingual aspect of the anterior mandible (symphysis). Bilateral anterior fractures of the mandible may cause the tongue to fall back into the oropharynx and a conscious patient with this injury will sit up and forwards to protect his own airway. In an unconscious supine patient without airway protection, this fracture is fatal.

The face has an extremely good blood supply and facial fractures, particularly of the mid-face, can cause catastrophic haemorrhage. A significant portion of this may go unnoticed in an unconscious supine patient as it can accumulate in the airway, pharynx, and stomach.

Basics of energy transfer

Energy transfer is an important concept to explain when dealing with any form of trauma. It is now understood that the total force is not as important as the amount of energy transferred into the tissues, which is directly proportional to the level of tissue damage that will occur. This is most easily exemplified in ballistic trauma. A sniper's bullet travelling greater than the speed of sound will hit the face and pass through it causing a minimal damage. A handgun fires a bullet at much lower speed but the bullet often does not exit the tissues. All of the kinetic energy in the handgun bullet is therefore transmitted to the tissues, leading to more extensive damage.

Classification

Fractures of the lower third

The lower third of the face is made of the mandible and its teeth. The mandible forms a ring with the temporo-mandibular joint and the base of skull. A ring is difficult to break in only one place and therefore the mandible often fractures in two or more places. Frequently, these are in different places on each side and this has generally little impact on the airway, unless there is gross displacement or bilateral anterior fractures (Fig. 4). Gross displacement causes bleeding that can cause a large sublingual haematoma in effect reproducing the airway compromise of Ludwig's angina. As the roots of teeth act as a natural weak point in the mandible, teeth are often in the fracture line and can become displaced, loosened, or avulsed.

Fig 4

CT of mid-face trauma showing right Le Fort I and III with palatal split and comminute mandibular fractures.

Fig 4

CT of mid-face trauma showing right Le Fort I and III with palatal split and comminute mandibular fractures.

Fractures of the middle third

The mid-face is made up of the maxilla, zygoma, and lower half of the naso–orbito–ethmoidal complex. This part of the face houses the eyes, the nasal airway, maxillary sinuses, and maxillary teeth. The mid-face acts as the crumple zone to protect the brain from injury and is frequently involved in facial injuries. As complex mandibular injuries can result in airway compromise, so can middle third fractures. Importantly, these can result in significant haemorrhage and immediate life-saving measures may involve placement of Epistats, Rapid Rhinos™, Foley catheters, or equivalents and bite blocks such as McKesson's to splint the maxilla and tamponade bleeding points.

Le Fort fractures (Fig. 5) are common patterns of injury. It must be borne in mind that these patterns were produced on cadavers and do not occur so precisely in vivo.

Fig 5

Le Fort classification of facial fractures.

Fig 5

Le Fort classification of facial fractures.

In Le Fort I, the maxilla is fractured from the rest of the face and is often not as freely mobile as one might expect. Only in high energy transfer does the maxilla become loose and at risk to the airway. Le Fort II involves the maxilla and nasal complex fracturing from the facial bones and mobility is often more than Le Fort I. Le Fort III injuries are more significant and involve the whole mid-face dissociating from the base of the skull and facial bones. Frequently Le Fort injuries will occur in combination and involve the mandible.

Fractures of the upper third

The upper third is made of the frontal bone, sphenoid and upper half of the naso–orbito–ethmoidal complex. It contains the eyes and more of the paranasal sinuses (frontal, anterior and posterior ethmoids, and sphenoids). The frontal bone's weakness is the frontal sinus and the extent of pneumatization varies considerably between individuals. When the sinuses are large, the frontal bone may fracture and involve the anterior skull base. These fractures may be associated with dural tears, cerebrospinal fluid leak and, therefore, the risk of ascending infection.

Upper third fractures are of consequence to the anaesthetist because it is commonly necessary for tubes to be placed into the nose (Foley catheters, nasogastric tubes, and temperature probes). Due to fracture displacement and difficult clinical circumstances, they can end up in the frontal lobe. There is no absolute contra-indication for placement of these tubes in anterior skull base trauma, but adequate anatomical understanding that the nasal floor is horizontal when upright and caution is needed.

Assessment and management in Accident and Emergency department

When assessing any trauma patient, it is fundamental to consider the mechanism of injury and the amount of energy transfer. This will give the surgeon and anaesthetist an idea of the likely severity of injury and potential for impending airway embarrassment.

Although injuries to the face can be distracting, the team must follow the ATLS protocol when it comes to severe trauma. During the primary survey, definitive airway control may be necessary before complete evaluation of facial injuries. A proportion of patients with facial trauma may require early intubation before bleeding and swelling impede ventilation. There may be associated cerebral and cervical spine injury.

Airway compromise is suggested by signs associated with impaired air flow such as dyspnoea and stridor. Other signs may include drooling, odynophagia, tracheal deviation, and trismus, especially if associated with bleeding, subcutaneous emphysema of neck and chest, voice changes, burns, and unstable fractures of the face.8 Subtle changes should not be ignored.

Preoperative considerations for maxillofacial trauma surgery

This article excludes those patients who have already been intubated for definitive airway control as part of the ATLS primary survey. It assumes an adequate general preoperative assessment and should follow similar principles as outlined in the previous section for dental abscess surgery.

For the ward patient with isolated facial trauma, airway assessment should include the inspection of swelling, nasal patency, mouth opening, and Mallampati scoring. Trismus is often caused by pain and can disappear on induction of anaesthesia. However, it may persist for mechanical reasons and this needs to be discussed with the surgical team. Preoperative imaging should be reviewed. The route of repair also needs consideration, as it can be intraoral, subconjunctival or via a scalp flap. Different tracheal tubes (TTs) may be used: south facing oral R.A.ETM for zygomatic or orbital fractures, nasal for other fractures including mandibular, Le Fort fractures or any that involve malocclusion. Alternatives to oral intubation include tracheostomy or submental intubation. The need for a throat pack, postoperative intermaxillary fixation, and facial nerve monitoring should also be discussed.

Anaesthetic technique

The choice of anaesthetic technique will again be influenced by the airway evaluation and the difficulties anticipated. Blood in the airway can make some techniques more challenging and therefore vigilant planning and decision-making is necessary (see Table 1). Senior involvement is recommended.

Pain can decrease after fixation of fractures. The surgeons infiltrate local anaesthetic with vasoconstrictors during the procedure and paracetamol, non-steroidal anti-inflammatory drugs and long-acting opioids can be used in combination. I.v. dexamethasone is administered to decrease swelling, followed by subsequent doses for the first 48 h. Antibiotic prophylaxis is indicated in wounds with gross contamination, orally penetrating wounds, exposed cartilage, and devascularized wounds.8

The anaesthetist needs to be aware of and prepare for potential intra-operative complications. Reflex bradycardia during levering of a zygomatic fracture or manipulation of the mid-face can occur. This can be treated with anticholinergics such as atropine. Blood loss from facial fractures can be extensive and a large bore cannula, fluid replacement, and a recent group and save sample is a basic requirement. Other complications include TT damage, oculo-cardiac reflex, and wiring of the TT to the maxilla.9

Postoperative considerations

Extubation should be planned as prudently as intubation, bearing in mind that the degree of oedema can worsen in the first 48 h after the injury. This is especially true in the case of Le Fort II and III fractures. Throat packs should be removed at the end of the operation and the oropharynx suctioned for debris and clots. Wire cutters or scissors for elastic band fixation should be immediately available. Extubation should occur when the patient is fully awake, and emergency intubation drugs and airway equipment are instantly to hand. The surgical team should be in attendance until successful extubation has occurred.

Due to residual swelling, some patients may be admitted to a high dependency unit for close observation. Those that remain intubated and ventilated are sent to the intensive care unit.

Postoperative haematoma

Haematoma formation in the early postoperative period is an uncommon, but potentially airway-threatening complication of some maxillofacial operations, notably neck surgery, thyroid resections, and floor of mouth surgery.

The rate at which airway compromise occurs is variable. Emergency decompression of the haematoma by removing the clips/sutures and manually evacuating the haematoma with a Yankaur sucker may not alleviate the airway obstruction adequately due to oedema that results from venous congestion. The method of securing the airway should take into consideration information from the initial operation but it is expected to be more challenging and warrant expert participation.

Conclusions

Anaesthesia for common oral and maxillofacial emergency cases can present significant challenges to the anaesthetist. They can often be patients who are previously fit and well but who now have ‘temporarily’ difficult or compromised airways. No ‘one size fits all’ method is possible and careful assessment and planning, effective communication, and early senior involvement are paramount to a successful outcome. The NAP 4 project highlights that ‘Plan A's’ can and do fail. Well thought through back up plans are essential to the airway management strategy, in these cases.

Declaration of interest

None declared.

References

1
Cook
T
Woodall
N
Frerk
C
Cook
T
Woodall
N
Frerk
C
Executive summary
4th National Audit Project: Major Complications of Airway Management in the United Kingdom
 , 
2011
London
RCoA
(pg. 
8
-
10
)
2
Patel
A
Pearce
A
Parcy
P
Cook
T
Woodall
N
Frerk
C
Head and neck pathology
4th National Audit Project: Major Complications of Airway Management in the United Kingdom
 , 
2011
London
RCoA
(pg. 
143
-
54
)
3
Clement
ID
Shaw
I
Kumar
C
Dodds
C
Infection and oral maxillofacial surgery: implications for anaesthesia
Oxford Textbook of Anaesthesia for Oral and Maxillofacial surgery
 , 
2010
Oxford
Oxford University Press
(pg. 
144
-
9
)
4
Athanassiadi
KA
Infections of the mediastinum
Thorac Surg Clin
 , 
2009
, vol. 
19
 (pg. 
37
-
45
)
5
Kirkpatrick
N
Facial and orbital injuries
Surgery
 , 
2004
, vol. 
22
 (pg. 
185
-
90
)
6
Hutchinson
IL
Magennis
P
Shepherd
JP
, et al.  . 
The BAOMS United Kingdom survey of facial injuries part 1: aetiology and the association with alcohol consumption. British Association of Oral and Maxillofacial Surgeons
Br J Oral Maxillofac Surg
 , 
1998
, vol. 
36
 (pg. 
3
-
13
)
7
Jeroukhimov
I
Cockburn
M
Cohn
S
Thaller
SR
Facial trauma: overview of trauma care
Facial Trauma
 , 
2004
New York, NY
Marcel Dekker
pg. 
11
 
8
Mc Kay
MP
Mayersack
RJ
Facial trauma in adults
 
9
Ross
LL
Schendel
SA
Cornaby
T
, et al.  . 
Jaffe
RA
Samuels
SI
Craniofacial surgery
Anesthesiologist's Manual of Surgical Procedures
 , 
2004
Philadelphia, PA
Lippincott Williams & Wilkins
(pg. 
896
-
902
)
10
Assael
LA
Klotch
DW
Manson
PN
, et al.  . 
Manual of Internal Fixation in the Cranio-Facial Skeleton, Le Fort I-III Fractures
 , 
1997
Springer
pg. 
109
  
Fig. 4.2.1