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10.0 Maxillofacial Infections

Learning Outcomes:

1. List the common causes of maxillofacial infections 2. Describe the anatomical spaces that can be involved in maxillofacial

infections and their inter relationships 3. Describe the generic treatment of maxillofacial infections 4. List the danger signs of life threatening maxillofacial infections

Maxillofacial infections may be classified on the basis of complexity, cause, site or stage. There are numerous causes of soft tissue infection in the head and neck region which are related to the anatomical structures present. The origin and anatomical position of the source of infection will determine subsequent development, spread and ultimate outcome. The most common source of infection within the head and neck, as seen by Maxillofacial Surgeons, is the dentition. Clinical course of a tooth abscess:

1) Death of the tooth pulp.

2) Infection around the apex of the tooth.

3) Acute inflammatory condition related to the periodontal membrane and periapical structures with oedema, neutrophil infiltration and acute suppuration. The tooth becomes loose and tender, pus accumulates around the apex of the tooth within the bone and the patient experiences an acute, throbbing, well-localised pain.

4) Suppuration may extend through the cancellous spaces and eventually

may track through the cortical plate of the bone producing swelling beneath the periosteum or a “gum-boil”.

5) Subsequent infection may be limited by fascial planes within anatomical

spaces or spread beyond, as in the case of Ludwig’s Angina.

Spread of Soft Tissue Infection within the Head and Neck Region:

Spread – Type of Spread

1) Local progression through the tissue.

2) By lymphatics to regional lymph nodes.

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3) Haematogenous spread leading to thrombophlebitis, bacteriaemia or

septicaemia.

Factors which influence of spread of infection:

1) Host resistance may be compromised in situations where there is immune suppression e.g. pts on steroids and other immunosupressants; diabetics; leukaemia.

2) Anatomical sites – pus may escape from the epithelial surface and discharge

through mucosa or skin.

3) Barriers to spread of infection, muscle or fascial planes.

Anatomical barriers to the spread of infection:

1) Investing layer of deep cervical fascia which blends into the deep and superficial parotid fascia.

2) Pre-vertebral fascia (anterior to pre-vertebral muscles).

3) Pre-tracheal fascia and carotid sheath.

Muscles which Limit Spread of Infection:

1) Mylohyoid diaphragm sheet of muscle in the floor of the mouth which separates sublingual from submandibular spaces.

2) Buccinator – thin sheet of muscle which may direct spreading infection into the

mouth or onto the skin. 3) Masseter muscle, submasseteric abscess.

4) Superior constrictor muscle with medial pterygoid limit the boundary of the lateral pharyngeal space.

Anatomical Spaces where Pus Accumulates:

1) Submental.

2) Submandibular.

3) Sublingual.

4) Buccal.

5) Submasseteric.

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6) Parotid.

7) Pterygomandibular.

8) Lateral pharyngeal.

9) Palatal.

10) Canine fossa.

11) Infratemporal.

1) Submental

Surgical anatomy:

Between mylohyoid muscles superiorly and the investing layer of deep cervical fascia below covered by platysma, superficial fascia and skin; bounded laterally by the anterior bellies of the digastric muscle and contain submental lymphnodes. Clinical features:

Firm swelling beneath the chin.

2) Submandibular space infection. Surgical Anatomy:

Compartment containing submandibular salivary gland and lymph nodes beneath the investing layer of deep cervical fascia and platysma and the inferior border of the mandible. Mylohyoid muscle superiorly, anteriorly communicates with the submental space and anteromedially with the sublingual space. Clinical features:

Swelling within the submandibular triangle.

Bulges over the lower border of the mandible.

3) Abscess formation related to buccinator muscle.

Surgical Anatomy:

The buccinator is a wide thin muscle which forms the substance of the cheek. Its line of origin is horseshoe-shaped, runs along the alveolar process from the upper first molar posteriorly round onto the mandibular third molar with attachment to the pterygo-

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mandibular raphe. The fibres decussate into the upper and lower lip anteriorly. Infection in upper or lower molar teeth may be directed into the mouth or into the face depending upon whether the source of infection lies within or outside the perimeter of the buccinator attachments. The direction of spreading infection from a third molar tooth in the mandible depends on a complex series of circumstances including the site, angulation and attachment of the buccinator muscle. (See Fig 1) Clinical features:

Gum-boil or cheek swelling. Fig 1

4) Buccal Space

Surgical anatomy:

Anteriomedially bounded by the buccinator muscle and posteriomedially by the masseter and anterior border of the ramus of the mandible. Lateral cover is from fascia & skin. The buccal space contains buccal fat pad and is a potential space, frequently swollen with oedema or blood following surgical removal of a wisdom tooth.

5) Sublingual Infection

Soft tissue beneath the tongue above the origin of the mylohyoid muscle. (See Fig 2)

Clinical features:

Swelling beneath the tongue when viewed through the mouth. The swelling may deflect the tongue medially and superiorly. Speech may be affected (“hot-potato” voice), then swallowing, then airway. It may spread to involve the submandibular space or across the midline to involve the contra-lateral sublingual space.

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Fig.2

6) Submasseteric Space

Surgical anatomy:

Beneath the masseter muscle on the lateral aspect of the mandible with the ascending ramus of the mandible on the medial aspect. Clinical features:

Significant trismus (potentially big anaesthetic problems), acute tenderness on palpation of the masseter muscle extra-orally. The extra-oral appearance may be normal. May be little by way of facial swelling.

7) Pterygomandibular Space

Surgical Anatomy:

Pterygomandibular space is an area between the medial surface of the mandible and the medial pterygoid muscle. The two heads of the medial pterygoid muscle arise from the medial surface of the lateral pterygoid plate and the lateral surface of the tubercle of the palatine bone and tuberosity of the maxilla. Within the pterygomandibular space runs the lingual nerve, the mandibular nerve and the inferior alveolar artery. The space communicates posteriorly with the lateral pharyngeal space. Clinical features:

May be associated with swelling in the submandibular or buccal spaces. Limitation of mouth opening. Neuropraxia is rare. The abscess usually points at the anterior border of the ascending ramus. (See Fig 3)

8) Lateral Pharyngeal Space

Surgical Anatomy:

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Medial wall is the superior constrictor muscle with styloglossus and stylopharyngeus. The lateral wall is fascia covering the medial pterygoid, the angle of the mandible and submandibular salivary gland. Posteriorly the space abuts on the parotid gland. The posterior border is the prevertebral fascia and upper part of the carotid sheath. Clinical features:

Systemic symptoms are frequently noted with a lateral pharyngeal infection, pain on swallowing and trismus are frequent features. The tonsil and lateral pharyngeal wall are pushed towards the opposite side of the mouth and the uvula can be deflected medially.

Fig.3 Pterygomandibular space

9) Peritonsillar Space (Quinsy)

Surgical anatomy:

The anatomical space is the superficial connective tissue bed of the faucial tonsil between the pillar of fauces and the superior constrictor muscle. Acute infections penetrate the tonsil. Clinical features:

Acute pain on one side of the throat, difficulty in mouth opening, speech becomes awkward with the classic feature of “hot potato voice”, dribbling from the mouth may be noted because of extreme pain on swallowing.

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10) Bilateral swelling of submandibular and sublingual spaces (Ludwig’s Angina)

(Fig 4) Surgical anatomy:

To fulfil the diagnosis of Ludwig’s Angina both submandibular and sublingual spaces bilaterally must be involved in swelling or infection. Clinical features:

Massive brawny swelling over the anterior part of the neck. The floor of mouth is swollen and the tongue is raised and maybe protruding from the mouth. The patient is

usually systemically very unwell with increasing dyspnoea. This is a SURGICAL

EMERGENCY.

Fig.4

11) Other sites & presentations of infection:

a) Canine & lateral incisor teeth commonly cause a swelling within the canine fossa and a facial swelling which obliterates the naso-labial fold. Spread towards the orbit is potentially serious . Orbital cellulitis can progress to cavernous sinus thrombosis.

b) Palatal abscesses present with a smooth ovoid swelling under the palatal

mucoperiosteum. Teeth commonly involved are lateral incisors and the palatal roots of the first molars.

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c) Periapical Infection in relation to the Maxillary Antrum

Surgical anatomy:

Close proximity of the maxillary molar teeth and premolar (most commonly implicated is the second molar.) Pus may be directed into the maxillary antrum producing acute sinusitis, pain, erythema, discharge from anterior or posterior nares. d) Primary skin infections

These commonly arise from skin pustules (especially if inexpertly squeezed!), epidermoid cysts, trauma (often quite minor e.g shaving cuts), erysipelas.

Treatment for Soft Tissue Swelling/Abscess Formation

REMOVE THE CAUSE (i.e. extract the tooth, open & extirpate the pulp)

INCISION & DRAINAGE (“Never Let The Sun Set On Undrained Pus”).

ANTIBIOTICS (usually intravenously initially).

Antibiotics are considered third in the management of infections after you have paid due consideration to removal of the cause and drainage of pus (which is often achieved by

removing the cause). Try to get a sample of pus before you start antibiotics (swab, needle aspirate, blood culture) Amoxycillin (± metronidazole) is a sensible first choice for dentally related infections. Second choices include cefuroxime, erythromycin, clindamycin. Skin infections & other suspected staphylococcal infections and bites and should be treated with augmentin (or a combination of penicillin & flucloxacillin ± metronidazole) or erythromycin.

If you have any doubts or queries consult a microbiologist.

Take a full blood count noting particularly the white cell count – look for evidence of a normal neutrophilia in response to a bacterial infection. If white cell count very high or very low, is this indicative of immunosuppression or a blood dyscrasia. Check the glucose. Could this infection be a presentation of previously undiagnosed diabetes? If the patient is a known diabetic then concurrent infection may make diabetic control difficult. Treatment with Steroids, Acetazolamide, Mannitol and antihistamines should only be undertaken following senior consultation.

Drains

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Extra-oral: Corrugated

Blake type

Intra-oral: Not usually of help. Can use corrugated drains (suitably secured) or ribbon gauze + Whitehead’s varnish.

A drain usually stays in place for 24-48 hours until most/all of the pus has discharged. The instruction to “shorten a drain” means to gradually withdraw the drain from the incision site so that the abscess cavity closes down behind the drain leaving no residual

dead-space. It does not mean cut the external end of the drain ever shorter until it disappears into the hole!

Summary

Maxillofacial infections are common and most can be treated by simple measures without the need for hospital admission. They are commonly due to teeth.

Apply the principles: Remove the cause (if possible)

Drain the pus

Consider antibiotics

They are occasionally life-threatening due to airway compromise.

Indicators of a serious infection include:

Pyrexia/systemic upset

Trismus

Problems speaking, swallowing or breathing

Involvement of the sublingual, paratonsillar or lateral pharyngeal spaces

A simple mnemonic can be helpful:

P pyrexia

U unwell

S swelling – especially extra-oral

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T tender

U unable to swallow

L limitation in opening

E eye involvement

S speech problems

If in doubt ask for advice from your senior.

Do not underestimate maxillofacial infections.