|Subcutaneous / Surgical Emphysema
|Last Updated 7th September 2012
Sub-cutaneous emphysema can be defined as the collection of air (or another gas)
below the sub-cutaneous tissues (in this case of the head and the neck).
Sub-cutaneous emphysema due to dental procedures is uncommon.
How it happens:
In the dental setting, it usually occurs when high speed dental hand-pieces are
being used and the dental bur lacerates the adjacent mucosa.
These hand-pieces are air-turbine driven and expel high pressure air downwards
towards the cutting surface of the bur. Once a breach in the mucosa is made, air
under pressure is able to track sub-cutaneously.
This can typically happen during restorative dentistry, dental implant surgery,
endodontic surgery, periodontal treatment or during tooth extraction (particularly of
the lower wisdom teeth) when air syringes, air-water– cooled high-speed dental
handpieces or spray/jet devices are used.
It can also occur in association with Head & Neck surgery, soft tissue infection,
trauma, foreign bodies or neoplasms (cancers) of the aero-digestive (mouth, nose,
windpipe & gullet) tract, any condition leading to rupture of bronchial alveoli with
consequent pneumo-mediastinum (eg, asthma or pulmonary baro-trauma) or
Signs & Symptoms:
Although alarming to the patient and clinician, it is usually a benign condition that
resolves over 3 – 10 days as the air is resorbed into the blood stream for eventual
excretion via the lungs.
Sub-cutaneous / surgical emphysema is characterized by soft tissue swelling of
sudden onset, usually developing within seconds or minutes. Palpation of the
affected tissues reveals crepitus (crackling), an important diagnostic feature. In
most cases, this sign is detected immediately however there are reports in which it
appears later, making diagnosis difficult.
Discomfort is a variable finding (can happen with sub-cutaneous emphysema when
it causes tension in the involved tissues).
Most patients who develop sub-cutaneous emphysema after a dental procedure
have only moderate local swelling. However, spread of larger amounts of air into
deeper spaces may sometimes cause serious complications. For example, the
bases of the lower molars directly communicate with the sub-lingual & sub-
These spaces, in turn, communicate with the para-pharyngeal & retro-pharyngeal
spaces, where accumulation of air may lead to airway compromise. The retro-
pharyngeal space (“danger space”) is the main route of communication from the
mouth to the mediastinum. Once air enters the mediastinum, it can also reach the
pleural cavity, the pericardium & even the retro-peritoneum. Consecutive cases of
pneumo-thorax & pneumo-pericardium may cause cardiac and/ or pulmonary
failure. The presence of pain both in the thorax & in the back, would suggest the
presence of this type of emphysema & a thorax X ray to confirm the diagnosis is
Cases of fatal air embolism & optic nerve damage (by access of air to the orbits)
have also been described. Furthermore, dissemination of oral flora micro-
organisms along the emphysematous tracts may be responsible for soft tissue
infections (eg. deep neck infection and mediastinitis) & sepsis.
Provided that there is no airway compromise, sub-cutaneous / surgical
emphysema can be treated conservatively (observation & reassurance of the
patient). The prognosis is good. Infection is a potential risk since the introduction
of air and not sterile water could cause serious effects to the health of the patient &
antibiotics are usually prescribed although this remains controversial.
Emergency intervention could be required in severe cases with evidence of airway
compromise & dysphagia.
It is important to advise the patient that they must avoid increasing intra-oral
pressure, such as by blowing the nose vigorously or playing musical instruments
which could introduce more air.
In the vast majority of cases, emphysema resolves within 2 - 3 days, although
residual swelling may be evident for up to 14 days.
In severe cases, immediate medical attention is mandatory. Tracheostomy may
become necessary in case of retro-pharyngeal space emphysema with
consecutive airway compromise. It has also been reported that administration of
100% oxygen via a non rebreather mask can hasten resolution of the emphysema,
because oxygen, which replaces the air, is more readily absorbed. Prophylactic
administration of antibiotics, preferentially Co-Amoxiclav, is recommended to
prevent secondary infections.
|Photos of Surgical-Subcutaneous Emphysema