This disorder may result from the entry of gas into any area where the integument, skin or mucosa is broken and in contact with a gas space. Although the classical site involves the supraclavicular areas in association with tracking mediastinal emphysema from pulmonary barotrauma, other sites are possible.
Orbital surgical emphysema, severe enough to occlude the palpebral fissure completely, may result from diving with facial skin, intranasal or sinus injuries. The most common cause is a fracture of the naso-ethmoid bones. The lamina papyracea, which separates the nasal cavity and the orbit, is of egg-shell thickness. When these bones are fractured, any increase in pressure in the nasal cavity or ethmoidal sinus from ascent or a Valsalva manoeuvre may force air into the orbit (see Chapter 8 and Plate 3).
Surgical emphysema over the mandibular area is common with buccal and dental lesions. The surgical emphysema, with its associated physical sign of crepitus, can be verified radiologically as it tracks into loose subcutaneous tissue.
Treatment is by administration of 100 per cent oxygen with a non-pressurized technique, and complete resolution occurs within hours. Otherwise, resolution may take many days. Recompression is rarely indicated, but diving should be avoided until this resolution is complete and the damaged integument has completely healed.