Subcutaneous Emphysema and Pneumomediastinum Following a Dental Procedure without Tooth Extraction: A Case Report and Literature Review

Authors: Reika Matsushita, Jun Ehara, Tomohiro Yamaba, Kosuke Nasu, Yoichiro Sugita, Eiji Hiraoka

Abstract

Pneumomediastinum refers to the accumulation of air in the mediastinum, which may occur due to trauma, esophageal perforation, or spontaneously. Although rare, dental procedures, especially those involving air turbine drills, can cause mediastinal emphysema. Most reported cases are related to tooth extraction; however, nonextraction procedures may also be associated with this complication. We report the case of a 65-year-old woman who developed facial and neck swelling following a dental procedure using an air turbine drill, and provide a review of the relevant literature.

Introduction

Pneumomediastinum refers to the presence of air in the mediastinum, and can occur spontaneously or due to secondary causes, including traumatic, non-traumatic, and iatrogenic origins. Most cases result from complications from abdominal, head, neck, or chest surgeries as well as dental surgery, intubation, mechanical ventilation, and other medical procedures (1). Although rare, dental procedures, particularly those involving air turbine drills, may lead to mediastinal emphysema, even without tooth extraction (2).

A timely diagnosis and management of pneumomediastinum is crucial. When it is caused by non-extraction dental procedures, it is often benign, whereas cases arising from other etiologies may result in severe outcomes (3-5). We herein present a case of mediastinal and subcutaneous emphysema caused by an air turbine drill during a dental procedure, and review the relevant literature.

Case Report

A 65-year-old woman with no significant medical history presented to the emergency department with facial and neck swelling that had developed two hours earlier. Earlier that day, her dentist had used an air turbine drill to remove an implant connection between the 6th and 7th teeth of her left mandible. Approximately one hour after the treatment and 15 min after trimming of the implant superstructure began, the patient noticed swelling in her face and neck. The dentist immediately stopped the procedure and referred the patient to the emergency department. The patient reported mild pressure over the clavicle, but denied dyspnea, cough, or chest pain. She denied any recent trauma or neck surgery.

Upon review of the systems, the patient denied respiratory, abdominal, urinary, neurological, dermatological, or cardiovascular symptoms. Her medical history was notable only for allergic rhinitis and atopic dermatitis. The surgical history included right hemicolectomy for colon cancer, clavicle fracture fixation, and total hysterectomy for uterine fibroids. She was not on any medication other than topical cream for atopic dermatitis. She had seasonal hay fever, but no known food or drug allergies. The patient's family history was unremarkable. The patient was a non-smoker and consumed approximately 1 liter of beer three to four times per week. The patient lived independently.

On physical examination, the patient was alert and oriented with a Glasgow Coma Scale score of 15. Her vital signs were blood pressure, 143/81 mmHg; heart rate, 71 beats per minute; respiratory rate, 20 breaths per minute; oxygen saturation, 99% on ambient air; and body temperature 36.6°C. A physical examination revealed swelling and crepitus in both cheeks, the mandible, the anterior neck, and bilateral supraclavicular areas (Fig. 1). The mucosal integrity was intact and there was no obvious intraoral contamination. Lung auscultation and other physical examinations were unremarkable. Hamman's sign was not observed.

Laboratory tests showed a mildly elevated white blood cell count, but the C-reactive protein level was within normal limits. A computed tomography (CT) scan of the head and chest, taken 1 h after the onset of the symptoms, revealed extensive subcutaneous emphysema involving the cheeks, neck, supraclavicular regions, and left thoracic wall, as well as pneumomediastinum (Fig. 2). Her electrocardiography and transthoracic echocardiography findings were normal.

We diagnosed the patient with pneumomediastinum due to dental procedures based on the medical history and CT findings. The patient was admitted for observation and was administered intravenous ampicillin-sulbactam to prevent mediastinitis. Over the next several days, swelling and crepitus gradually resolved. A repeat CT scan on day 5 showed significant improvement. The patient was discharged 7 days after discontinuation of antibiotics. The patient remained asymptomatic at the 1-month follow-up visit.

Discussion

This case illustrates a rare instance of pneumomediastinum and subcutaneous emphysema following use of an air turbine drill during a dental procedure without tooth extraction. Pneumomediastinum can occur spontaneously or as a secondary condition, with iatrogenic causes being one of the recognized pathways (6). Although rare, dental procedures, particularly those using high-pressure air or water syringes, can cause pneumomediastinum and subcutaneous emphysema (2). Common symptoms include dyspnea, cough, chest pain, and dysphagia, which may appear during or after the procedure. Crepitus over the cheek, neck, and chest wall is a characteristic clinical sign. Hamman's sign, a crunching sound synchronous with the heartbeat on cardiac auscultation, also indicates the presence of pneumomediastinum (7). A diagnosis is made through a combination of history, physical examination, and imaging, such as chest radiography or CT scans (1). Differential diagnoses include allergic reactions, hematoma, cellulitis, and angioedema (1). When pneumomediastinum occurs as a result of dental treatment, it may go undiagnosed because of its asymptomatic course (1). Additionally, it can sometimes be misdiagnosed as an allergic reaction because neck and facial swelling mimic the manifestation of angioedema (8).

Air turbine drills, which are commonly used in dental procedures, operate at high rotational speeds (450,000 rpm) powered by compressed air at 3.5-4.0 kgf/cm^2^. They also utilize water sprayers for cooling and debris removal (9). Compressed air can disrupt the oral mucosa and track through cervical fascial planes into the mediastinum, resulting in pneumomediastinum (1,8,9).

We conducted a review of the relevant literature (2015-2024) using PubMed with the following search “dental," “treatment," “procedure," “mediastinal emphysema," and “pneumomediastinum." Fifty cases from 44 articles were identified and are summarized in Table 1 (2,9-51). The median age (interquartile range) was 36 (23.8, 54.3) (range: 4 to 76 years). Twenty-eight of the patients (56%) were female. The mortality rate was 0%. Twenty-eight cases (56%) involved tooth extraction, while the use of an air turbine drill without extraction accounted for 9 cases (18%). Of the 50 patients, 27 underwent mandibular tooth procedures alone, 8 underwent maxillary tooth procedures, and 6 underwent both procedures. Among the 11 cases involving maxillary teeth with detailed descriptions, 5 had periorbital symptoms (swelling, proptosis, and crepitus). Prophylactic antibiotics were administered to 47 patients, with no progression to mediastinitis. Three cases were managed without antibiotics and seven were managed without hospitalization, all with favorable outcomes. One case involving tooth extraction led to symptom progression, requiring surgical decompression of air. The patient also had vocal cord paresis 2 months later, possibly due to scarring after resolution of emphysema, causing injury to the recurrent laryngeal nerve, which improved after injection laryngoplasty (29). No similar complications have been reported in other cases.

The prognosis of pneumomediastinum following air turbine drill use is generally favorable, with most cases resolving within a week. Prophylactic antibiotics are often administered to prevent oral bacteria from spreading to the parapharyngeal and retropharyngeal spaces, which can lead to cellulitis or necrotizing fasciitis (3). However, the effectiveness of antibiotics remains unclear as some cases have improved without their use. Therefore, it is plausible that the favorable outcome in this case might be due to spontaneous resolution rather than antibiotic treatment. This favorable prognosis contrasts with idiopathic or traumatic pneumomediastinum, which carries a higher risk of complications, such as mediastinitis (Table 2) (3-5).

When pneumomediastinum is identified, it is essential to inquire about the recent history of dental procedures to accurately determine its cause. Based on the case series, pneumomediastinum following dental procedures generally has an excellent prognosis, as long as the respiratory status and development of complex infection are appropriately monitored.

Conclusion

This case highlights a rare complication of pneumomediastinum following a dental procedure using an air turbine drill, even without tooth extraction. Despite the theoretical risk of infection, the prognosis is generally excellent with close monitoring. An early diagnosis and appropriate management are crucial to ensure favorable outcomes.

Written informed consent was obtained from the patient for the publication of this report.

The authors state that they have no Conflict of Interest (COI).