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Subcutaneous / Surgical Emphysema
Last Updated 7th January 2020
Definition:

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 sometimes pneumothorax.


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-mandibular spaces.

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 mandatory.

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.  


Treatment:

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
Useful Articles:


CMA J 1977.  Subcutaneous Emphysema during Dental Treatment

J Laryngology & Otology 1999.  Surgical Emphysema following Dental Treatment

BDJ 2000.  Surgical Emphysema & Pneumomediastinum complicating Dental Extraction

JABFP 2003.  Brief Reports.  Pneumothorax During Dental Care

Emergency Medicine Australasia 2004.  Case Report.  Extensive Surgical Emphysema Following Restorative Dental Treatment

Arch Dermatol 2005.  Soft Tissue Cervicofacial Emphysema After Dental Treatment.  Report of 2 Cases With Emphasis on the Differential Diagnosis of
Angioedema

Med Oral Patol Oral Cir Bucal 2007.  Subcutaneous Emphysema Secondary to Dental Treatment.  A Case Report

Int J Odontostomat 2009.  Subcutaneous Emphysema after Ultrasonic Treatment.  A Case Report

Postgrad Med J 2009.  Rare Complications of Surgical Emphysema & Pneumomediastinum Occurring Post-Dental Extraction

J Oral Maxillofac Surg 2009.  Iatrogenic Subcutaneous Emphysema of Dental and Surgical Origin.  A Literature Review

J Oral Maxillofac Surg 2010.  Cervicofacial Subcutaneous Emphysema.  Case Report & Review of Literature

Ann Thorac Surg 2010.  Iatrogenic Pneumomediastinum & Facial Emphysema After Surgical Tooth Extraction

Braz Dent J 2011. Subcutaneous Emphysema During 3rd Molar Surgery.  A Case Report

J Clin Exp Dent 2011.  Subcutaneous Emphysema resulting from Surgical Extraction without Elevation of a Mucoperiosteal Skin Flap

Int J Clin Exp Med 2013.  Case Report.  Facial & Cervical Emphysema after Oral Surgery - A Rare Case

Austral Dent J 2017.  Subcutaneous Emphysema Secondary to Dental Extraction - A Case Report

Case Reports in Dentistry 2017.  Massive Cervicothoracic Subcutaneous Emphysema & Pneumomediastinum Developing during a Dental Hygiene
Procedure