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ISSN : 1225-1577(Print)
ISSN : 2384-0900(Online)
The Korean Journal of Oral and Maxillofacial Pathology Vol.39 No.4 pp.607-614

Pneumomediastinum and Subcutaneous Emphysema after Periodontal Treatment Using Air-Flow Equipment : A Case Report

Jung Hyeon Lee*, Kang Hyuk Kim, Joon kyu Kim, Je Uk Park, Chang Hyen Kim
Department of Oral and Maxillofacial Surgery, Seoul St. Mary’s Hospital The Catholic University of Korea, Seoul, Korea
Correspondence: Chang Hyen Kim Department of Oral and Maxillofacial Surgery, Seoul St. Mary’s Hospital Banpo-daero, Seocho-gu, Seoul 137-701, Korea. Tel: +82-2-2258-1781, Fax: +82-2-537-2374
July 28, 2015 July 30, 2015 July 31, 2015


Subcutaneous emphysema is a rare but serious side effect of dental and oral surgery procedures. The condition is characterized by air being forced underneath the tissue, leading to swelling, crepitus on palpation, and with potential to spread along the fascial planes to the periorbital, mediastinal, pericardial, and/or thoracic spaces. A wide range of causes have been documented for the origin of subcutaneous emphysema during dental treatment including: crown preparations, other operative procedures, endodontic therapy, extractions, as well as oral surgery procedures.

The patient was a 58-year-old woman who presented to the Seoul Saint mary’s hospital emergency department with a chief complaint of facial edema, dyspnea and chest discomfort after periodontal treatment using an air-flow equipment in local dental clinic. During treatment in the emergency department, oxygen therapy and intravenous injection of steroid and anti-histamine was done. it was noted that the patient had pain and swelling on left lower molar region, pus discharging on same site. Severe edema was observed on periorbital region to neck with heatness. An audible crepitus sound was heard during palpation on facial area. Neck CT scan and antibiotic therapy was done, as symptom suggesting dental abscess is observed. 3 hours after injection of antibiotics, the patient’s symptom was relieved, but she felt chest discomfort continuously. CT scan with constrast depicted confluent and extensive soft tissue emphysematous changes involving face and deep neck spaces and pneumomediastinum. The patient was refered to thoracic surgery department, oxygen therapy was decided continuously. After 10 hours, patient’s chief complaint was resolved, and discharged. After 1 week, all symptom was disappear and follow-up neck CT scan finding was disappearance of edema and pnuemomediastinum.

We report a case of cervical subcutaneous emphysema and pneumomediastinum occurring after periodontal treatment using an air-flow equipment and case on the diagnosis and treatment of subcutaneous emphysema and pneumomediastinum, along with a review of the literature.

Air-flow equipment를 사용한 치주치료 이후 발생한 종격동 기종과 피하기종 : 증례보고

이 정헌*, 김 강혁, 김 준규, 박 재억, 김 창현
가톨릭대학교 서울성모병원 구강악안면외과학교실



    Subcutaneous emphysema in the face and neck is a well-known clinical entity associated with trauma to the facial bone, trachea-bronchial tears, esophageal laceration, radical neck dissection, tonsillectomy, mandibular fractures, the use of high-speed air turbine handpieces during dental treatment1). The condition is characterized by air being forced underneath the tissue, leading to swelling, crepitus on palpation. Subcutaneous emphysema ia able to spread along the fascial planes to the periorbital, mediastinal, pericardial, and/or thoracic spaces2). In severe cases, the patient complains of neck pain, difficulty swallowing, swelling of the neck, dyspnea or chest pain. If that be so, the inflow of air into the lung or mediastinum should be suspected3). The outbreak during dental treatment is rare but it is generally known by side effect of root canal treatment, extraction of teeth, crown preparation as well as oral surgery procedures4). Especially, pneumomediastinum arises when the air leaks out from the lung into mediastinum, and then it can cause lethal complications such as dyspnea caused by mediastinal emphysema or pneumothorax5). Treatment may include analgesics for discomfort, prophylactic antibiotics to prevent secondary infection, setting the patient at ease that the problem is temporary6).

    Many cases reported in the dental literature derive from the use of a high-speed air-driven handpiece, an air/water syringe, or an oral irrigation device6).

    The purpose here to report a case of subcutaneous emphysema and pneumomediastinum following use of the air-flow equipment (AIR-FLOW®, EMS, Nyon, Switzerland, air polishing system) on a patient with peri-implantitis.


    A female patient, aged 59 years, visited the hospital as a patient in the emergency room when she suddenly felt her face and neck swollen, and had trouble breathing when she had received scaling using AIR-FLOW® (equipment for periodontal treatment, air polishing system) in a private dental practice.

    It seemed that the above phenomena had occurred during scaling of gum after flap elevation(Fig. 1).

    In the blood test results, there was slight inflammatory response with erythrocyte sedimentation rate 30 mm/h, lactate dehydrogenase 504 U/L, and there were no unusual features as a result of uroscopy, renal function test and electrocardiogram. She had no past medical history such as high blood pressure, diabetes, hepatitis or tuberculosis, and no medication related to these and drug hypersensitivity reaction. There was a whole edema in left face including periorbital region, neck area, upper chest, and there was crepitus during palpation. The patient complained of persistent dyspnea and chest pain, and the authors of this report could observe confluent and extensive soft tissue emphysematous changes involving face and deep neck spaces, Pneumomediastinum on the chest through neck computed tomography(CT) and chest radiograph(Fig. 2, 3, 4).

    So, the authors of this report diagnose the symptoms as subcutaneous emphysema and pneumomediastinum caused by the air-flow equipment (AIR-FLOW®, EMS, Nyon, Switzerland), and the patient received treatment as an outpatient for conservative care such as penicillin antibiotics injection to prevent secondary infection and oxygen feeding through nasal cavity. After 12 hours, the patient did not complain of persistent chest discomfort and breathing trouble. A CT scan on the 10th day of outpatient treatment was performed. Over the process, pneumomediastinum and emphysema had been reduced, but submandibular space, buccal space, masticatory space, parapharyngeal space and neck area continued to show symptoms(Fig. 5). A cooperative treatment with thoracic and cardiovascular surgery was performed, and no unusual features were observed.


    Postoperative subcutaneous emphysema and pneumomediastinum after dental treatment were first reported

    about 100 years ago when a musician blew a bugle immediately after tooth extraction7). Shovelton reported the following 4 cases which can be the causes of subcutaneous emphysema: actions of patient to rise intra-oral pressure, use of compressed air during surgery, difficult and long lasting surgery, case with no reason8). Gregory K. reported subcutaneous emphysema occurred after tooth extraction, restorative dentistry, root canal therapy, periodontal treatment, nose blowing, sneezing, habitual Valsalva maneuvers, and balloon blowing9). Minton and Tu reported subcutaneous emphysema occurred after fracture10), and Afzali et al. reported subcutaneous emphysema and pneumomediastinum occurred after extraction of the mandibular second molar11).

    Subcutaneous emphysema can be diagnosed with symptoms of swelling on the neck, neck pain, difficulty swallowing, wheezing and difficulty breathing, crackling noise, and crepitus during palpation on the neck area, and it is confirmed through CT of face and neck area as well as general neck and chest radiography12). Also voice change of the patient, dyspnea, chest and back pain, subcutaneous emphysema through chest radiography, and electrocardiogram change at 25% were identified as diagnostic features of pneumomediastinum12,13). The most distinctive auscultating feature is Hamman’s sign, which is a rustling sound heard during systole. In some cases, pneumomediastinum causes the rise of central venous pressure, hypoventilation, low blood pressure, and hypoxia, which require emergency medical treatment, due to the rise of venous pressure, brain pressure and airway pressure by pressing the breast wall and blood vessels14).

    In this case, there were sudden swelling of left face and neck area, dyspnea, chest discomfort during periodontal treatment using an air-flow equipment (AIR-FLOW®) in local dental clinic, confluent and extensive soft tissue emphysematous changes involving left face and left deep neck spaces and pneumomediastinum were diagnosed through CT and chest radiography. There was also a crepitus during palpation. On panoramic x-ray, peri-implantitis was observed in #37 implant periapical area.

    The mandible molar is connected with buccal space, submandibular space, and flows into secondary spaces such as temporal space, masseteric space, and pterygomandibular space through parapharyngeal space. Also, parapharyngeal space is connected to paravisceral space at both sides and visceral space, retropharyngeal space, vascular space and pretracheal space in the neck area are connected to mediastinum of chest. Therefore, a high pressure air emitted from a air-flow equipment can go through the primary and secondary spaces and reach mediastinum of the chest causing subcutaneous emphysema and pneumomediastinum. In this case, pneumomediastinum is considered to have occurred through fascial space. As this is the same as the spread way of odontogenic infection, which causes fatal complications such as mediastinitis, special attention should be paid.

    When there is a swelling on the face and neck area, it should be distinguished from vasogenic edema caused by cellulitis, angioedema or allergic reaction. As local edema caused by vasogenic edema or hemotelangiosis features a huge wheal response(a swollen rash from hives), but subcutaneous emphysema and pneumomediastinum are able to be distinguished from other diseases through sudden severe swelling without unusual tenderness, crepitus during palpation, accompanying of high fever, white blood cell number increase and Hamman’s sign which a resulting sound heard during a systole1).

    n this case, crepitus observed through physical examination has a big diagnostic significance as failure to recognize this symptom can be a clinical sign that can be misdiagnosed as an allergic reaction which can cause the delay of treatment and complications15).

    Subcutaneous emphysema and pneumomediastinum is known as the disease cured naturally without serious complications. Although it shows difference depending on the experience and disease seriousness of patient, most of them are recovered in one or two days, and completely cured in 10~14 days. Most of them are cured with conservative treatment, and it is important to have the patient receive emergency endotracheal intubation when edema and dyspnea are developed which explain the expected progress of the disease. Also, hospitalization is required in principle when there is a possibility of invasion into mediastinum and dyspnea. Although surgery is not considered because it can cause spread of subcutaneous emphysema, when the drainage of infected tissue is needed, it can be removed through surgery16). There are pressing of the involved area, insertion of needle, and several incisions and drainage and vent formation as invasive treatment. But recent treatments such as surgical decompression have no effect17). Also, when emphysema is severe, tracheostomy or endotracheal intubation need to be performed, but the subcutaneous emphysema and pneumomediastinum through dental devices have usually good prognosis, so performing tracheostomy is very rare.

    Generally, 100% oxygen feeding with nasal prong can reduce progress of disease. This reduces subcutaneous air by substituting it with oxygen in tissues and increases absorption of nitrogen in subcutaneous emphysema, speeds up absorption in tissues by reducing nitrogen partial pressure around tissues. The infection can also be occurred through the inflow of air into mediastinum, and this can cause fatal complications such as mediastinitis. So, preventive antibiotic therapy should be performed. As an antibiotic, both aerobic and anaerobic medicine should be chosen to prevent air infection in tissues at early stage and the antibiotic which is effective to the patient should be selected through microbial sensitivity test. Through this procedure, taking higher than normal dose of antibiotic and regulation of blood glucose through rigorous examination for diabetes together is very helpful18).

    In this case, authors of this report administered 2L/min 100% oxygen and antibiotics of amoxicillin+clavulanic acid which is effective not only for intra-oral resident bacteria but also for pseudomonas aeruginosa, an anaerobic bacteria which cause infection. Also metronidazole which is effective for an anaerobic bacteria is injected. 10 days after emergency treatment, slight subcutaneous emphysema was found on fascial space through neck CT. There were no unusual features in the cardiology and pulmonary examination results, and the patient’s discomfort disappeared.

    As complications of subcutaneous emphysema and pneumomediastinum, tension pneumothorax, pneumoperitoneum, or decline of cardiac function can occur19), fatal aeroembolism and mediastinitis have been reported20).

    When there were an increase of subcutaneous emphysema, continuous air leakage and the lung does not expand, bronchoscopy inspection for diagnosis can be performed to exclude airway rupture. If there is a pneumothorax, closed thoracostomy should be performed and the respirator shall be removed. If it cannot be removed, the maximum airway pressure should be reduced or the progress of subcutaneous emphysema should be prevented through adjustments to the inspiratory and expiratory time ratio.

    The introduction of the air-flow equipment (AIR-FLOW®, EMS, Nyon, Switzerland) has greatly facilitated plaque removal and polishing during dental prophylaxis. The instrument applies a mixture of air, water, and specially processed glycine powder. Recent studies have raised concern about its abrasiveness to cementum and composite restorative materials and also its irritation of the gingival margin21). It is tempting to consider the air-flow equipment (AIR-FLOW®, EMS, Nyon, Switzerland) as a means of irrigating pockets to remove subgingival plaque and to manage subgingival biofilm and to deliver Glycine-based powder solution. Pocket irrigation with chemotherapeutic agents such as glycine –based powder has been shown to effect a temporary reduction of periodontal pathogens22). Spray handpiece and nozzle have been used for this purpose. Caution must be used when approaching pockets with air-flow equipment (AIR-FLOW®, EMS, Nyon, Switzerland), especially deep ones. The working pressure (43.5-72.5 psi) far exceeds the 30 to 40 psi required to operate air turbine handpieces and air/water syringes, instruments frequently implicated in reported cases of subcutaneous emphysema. It has been demonstrated that an oral irrigating device can cause reversible damage to the sulcular epithelium at pressures ranging from 20 to 90 psi and to the outer keratinized epithelium at pressures greater than 70 psi23,24,25).

    This case shows that the inadvertent pointing of the air-flow equipment (AIR-FLOW®, EMS, Nyon, Switzerland) spray nozzle directly into a deep periodontal pocket during periodontal treatment can cause subcutaneous emphysema and pneumomediastinum. The conditions resolved in approximately 10 days without adverse sequelae. This case serves to reinforce the manufacturer’s instruction to angle the spray nozzle 30 to 60 degrees to the long axes of teeth and to secure a distance of 3 to 5mm from the sulcus to the incisal edge. By so doing efficient plaque and stain removal, in addition to some measure of pocket irrigation, can be accomplished at minimum risk.

    During dental treatments using high-speed air turbine handpieces such as treatment for trauma, root canal therapy or tooth extraction, subcutaneous emphysema and pneumomediastinum can occur, however, it is not very common. In case of air-flow equipment, it is relatively more rare. Therefore, dentists should be aware of its risk of complications and perform a detailed medical examination, medical history hearing and careful, conservative treatment to prevent complications. To prevent subcutaneous emphysema, minimum flap elevation and use of appropriate tool are needed. When subcutaneous emphysema occurs, the dentists should explain the risk of complications that can occur to the patient, and administer antibiotics and supply 100% oxygen.

    During dental treatment, in many cases, subcutaneous emphysema occurs after third molar was extracted, and there have been many cases reported in Korea where it occurred after tooth extraction. But, this case is only one where subcutaneous emphysema occurred after periodontal treatment using the air-flow equipment (AIR-FLOW®, EMS, Nyon, Switzerland) has developed to pneumomediastinum. So, this report shows its anatomical structure, possible symptoms, pathogenesis, diagnosis and complications, as well as treatment method with literature reviews.



    Panoramic view (initial examination) (arrow)


    Chest posterioranterial shows subcutaneous emphysema in the left neck area. (arrow)


    Computed tomography (CT) scans (initial examination) Dental CT shows Confluent and extensive soft tissue emphysematous changes involving left face and deep neck spaces. (mandibular, buccal, masticator, paraparyngeal spaces) (arrows)


    Computed tomography (CT) scans (initial examination) Neck CT shows that the thoracic spaces were connected to mediastinal spaces.


    Computed tomography (CT) scans (at outpatient



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