Submandibular and retropharyngeal emphysema

Radiology Forum Each month this section will bring to the reader of ORAL SURGERY, ORAL MEDICINE, AND ORAL PATHOLOGY information of practical relevance to the art and scienceof diagnostic imaging and diagnostic images with unusual interpretive features. Practical notes and radiographs will be accompanied by an explanation or inquiry. Please submit 5 X 7 inch glossy black-and-white prints of your illustrations. All materials for publication should be submitted to Dr. Allan G. Farman, Department of Primary Patient Care, School of Dentistry, University of Louisville, Louisville, KY 40292.

SUBMANDIBULAR EMPHYSEMA

AND RETROPHARYNGEAL

S

ubmandibular and retropharyngeal emphysema are uncommon complications of dental and oral maxillofacial surgical procedures. Compressed air from dental air syringes and air turbine handpiecesis the most common cause. This type of emphysema has also been reported in association with esophageal, laryngeal, pharyngeal, and cervicomaxillofacial trauma, extradural analgesia, and spontaneouspneumomediastinum. A 47-year-old woman was referred by the emergency service of our hospital with a diagnosis of submandibular and retropharyngeal emphysema caused by the use of a compressed-air syringe during periodontal surgery to the left mandibular lingual gingivae. Lateral and anteroposterior radiographs showed submandibular and retropharyngeal emphysema (Fig. 1). The patient was admitted to an intensive care unit for observation of the cardiothoracic and respiratory systems. Cardiopulmonary consultation was requested. Chest radiographs showed no emphysema. Treatment consisted of serial chest radiographs, elevation of the head 45 degrees,intravenous penicillin, and humidified oxygen administered by T tube. The patient was discharged 2 days after admission with complete resolution of all emphysema. The pathophysiology of this condition is readily understood when the anatomy of the superior constrictor muscle of the pharynx is reviewed. Air can dissect lingually into the submandibular space between the posterior border of the mylohyoid muscle, which attaches to the mylohyoid ridge on the lingual surface of the body of the mandible, and the mandibular attachment of the superior constrictor muscle of the pharynx, which is attached to the

Fig. 1. Lateral view. Arrow 1, Submandibular emphysema;arrow 2, retropharyngeal emphysema;arrow 3, danger space 4; arrow 4, prevertebral fascia.

posterior aspect of the same mylohyoid ridge. Air also may dissect retropharyngeally between the fascia and the outer surface of the superior constrictor muscle of the pharynx, which forms part of the lateral pharyngeal wall, to the retropharyngeal space, which is bounded anteriorly by this same muscle and posteriorly by the same fascia. Sheldon M. Mintz, DDS, MS Yakir Anavi, DMD Department of Oral and Maxillofacial Surgery Detroit General Hospital Detroit, Mich. 647