Case report: Subcutaneous emphysema following postoperative nausea

Abstract

Subcutaneous emphysema is a rare but potentially serious complication in dentistry and oral surgery resulting from the introduction of air into soft tissues. Although commonly associated with forward venting air-driven handpieces, cases have also been reported in the absence of an identifiable air source. We report an 18-year-old female who developed extensive subcutaneous emphysema following routine extraction of four third molars performed without the use of forward venting air-driven instruments, after multiple episodes of postoperative retching and emesis. She presented with progressive facial swelling and was transferred to a tertiary care center. Imaging demonstrated widespread air tracking within the masticator and submandibular spaces without abscess. The patient was managed conservatively with intravenous antibiotics, sinus precautions, and supportive care, with gradual resolution. Although uncommon, subcutaneous emphysema warrants vigilance due to risks of mediastinal spread and airway compromise. This case highlights that postoperative nausea and emesis may introduce air into unhealed extraction sites and emphasizes the importance of early recognition and prompt management.

Introduction

Subcutaneous emphysema in dental surgery arises when air is inadvertently forced into the soft tissues during procedures such as tooth extraction. Clinically, it is characterized by rapid swelling, palpable crepitus, and the potential for spread along fascial planes of the head and neck. ¹ The most frequent etiology is the use of air-driven handpieces during surgical extractions, though less common causes such as forceful nose-blowing following extraction have also been described. ²

While the incidence is rare, (less than 0.1% of dental extractions), ³ the potential morbidity can be significant. Air may track through cervical fascial planes into the mediastinum, posing a risk of life-threatening complications. This concern is heightened in cases involving mandibular extractions, where airway compromise may occur due to the anatomic pathways of air dissemination. Because subcutaneous emphysema may closely mimic odontogenic infection and allergic reaction, early recognition and differentiation are essential for appropriate management. Accurate differentiation between emphysematous air dissemination and odontogenic infection is paramount to avoid unnecessary surgical interventions, such as incision and drainage.

This case report describes a rare instance of post-extraction subcutaneous emphysema in the absence of forward venting air-driven handpiece and reviews diagnostic pearls, possible etiologies, management strategies, and preventive considerations considering existing literature. The authors certify that they have obtained all appropriate patient consent forms.

Case presentation

An 18-year-old otherwise healthy female presented to a community oral and maxillofacial surgery office for extraction of teeth #1, 16, 17, and 32. The provider indicated a routine extraction of impacted third molars. Patient did have nausea followed by retching and emesis subsequently. Within hours, she noted firm swelling bilaterally, which progressed overnight and the following day.

Patient presented to their community oral and maxillofacial surgery office 48 h postoperatively for evaluation. At this time, the patient was recommended to present to the nearest emergency department due to the severity of swelling involving the periorbital, mid and lower face areas. In the local emergency department, the patient was found to have leukocytosis (WBC 21.7) with left shift. There, the patient received intravenous steroids and had another episode of emesis. She was then transferred (now 72 h after procedure) to a tertiary care center for evaluation with oral maxillofacial surgery.

On presentation, the patient endorsed new dysphagia, but denied fever, drooling, dyspnea, or visual changes. Clinical examination revealed soft bilateral mid-face and lower facial swelling with crepitus, and without erythema or warmth. Imaging demonstrated extensive air locules within bilateral masticator spaces and submandibular regions, along with fat stranding and edema that extended to the superficial maxillary, malar, and periorbital regions bilaterally, without rim enhancement to suggest abscess formation. This is most consistent with a diagnosis of subcutaneous emphysema. Complete opacification of the left maxillary sinus with small air locules was also noted, suggesting that the positive pressure generated during vomiting may have forced air through a micro-communication in the sinus, as well as into the adjacent fascial spaces. The CT imaging guided the decision for conservative management by definitively ruling out mediastinal extension and the presence of rim-enhancing collections that would indicate abscess formation (Image 1).

Image 1.

Left – Clinical presentation demonstrating bilateral mid-face and lower face swelling.

Medical management was thus initiated. The patient was placed on strict sinus precautions and started on 1.5 g of IV ampicillin/sulbactam every 6 h while in the hospital as well as ondansetron 4 mg every 8 h as needed to prevent further emesis. She was then discharged on amoxicillin/clavulanate 875/125 mg every 12 h where she had decreased swelling on day 7 and near complete resolution on day 14.

Discussion

Subcutaneous emphysema is a rare but well-recognized condition in dentistry, with its first reported case dating back to 1870. In that instance, the patient, “sounded off on his bugle” after a premolar extraction, resulting in what was described as “traumatic emphysema.” ⁴ The advent of high-speed air-turbine handpiece in the 1950s was associated with an increase in iatrogenic cases of subcutaneous emphysema ⁵ as these are forward venting air-powered instruments. While most cases are self-limited, there is potential for rapid progression resulting in airway compromise, pneumomediastinum, tension pneumothorax, cardiac tamponade, air embolism, mediastinitis, necrotizing fasciitis and sepsis.^1,6–10 Imaging such as CT scan can delineate the extent and location of air, differentiating between conservative versus interventional management. ¹¹ The transition to rear-venting surgical handpieces and electric handpieces decreases the risk of subcutaneous air emphysema.

Clinical management should prioritize the mitigation of increased intraoral pressure to prevent the further tracking of air through fascial planes. Surgeons should advise patients to avoid forceful coughing or vomiting in the immediate postoperative period. Furthermore, the administration of prophylactic antiemetics should be considered in the perioperative phase to minimize the risk of emesis-induced emphysema. If crepitus is palpated, clinicians should transition to early imaging to establish a definitive diagnosis and assess the extent of air infiltration.

Recognizing the risk, the American Dental Association and American Association of Oral and Maxillofacial Surgeons recommended against the use of forward venting air-driven handpieces for surgical extractions since 1992. ¹² However, cases continue to be reported and have in fact noted to have a significant increase in recent years. ³ A recent systematic review by Jones et al. demonstrated that a little over half of the cases of subcutaneous emphysema following dental treatment were preceded by surgical extractions, particularly of posterior mandibular teeth, with 51% resulting from forward venting air-driven handpiece, 9% from air syringes and 10% from patient-related action. ³

Notably, handpieces are not the only culprits. Subcutaneous emphysema has also been reported in association with CO2 laser use. This was noted to be due to inadvertent introduction of compressed air from the cooling spray during incision or ablation.^1,13,14 Additionally, recent cases have emerged of non-extraction procedures, including restorative treatments, dental hygiene procedures, as well as peri-implant debridement with air-powered instruments.^7,15,16

In this case, the patient did not undergo a procedure with air syringes or forward venting air-driven handpieces. Patient also denied behavioral factors including playing wind instruments, using straws or forceful spitting. The proposed mechanism of air entry in this case follows a one-way valve model. ¹¹ The explosive positive-pressure gradients generated during retching force air into the submucosal layers at the surgical site. Once the air penetrates the buccopharyngeal fascia, it tracks along paths of least resistance into the masticator and submandibular spaces. This case falls into the 10% category of patient-related actions as classified by Jones et al., ³ occurring independently of air-driven instruments.

In literature, emesis-induced subcutaneous emphysema is rare. Our case represents the second reported case, but with distinct pathophysiological and anatomical features when contrasted with the single prior report by Gulati et al. ¹⁰ The periapical surgery in their report was also completed without the intraoperative introduction of compressed air, using a standard straight surgical handpiece. In their case, the patient developed severe systemic complications including pneumomediastinum, bilateral pneumothorax, and pleural effusion following an apicoectomy performed under general anesthesia. Conversely, our patient underwent routine surgical extractions of four third molars under intravenous sedation, with comparatively localized subcutaneous emphysema. This may be attributed to anatomical barriers and pressure dissipation mechanisms unique to multi-quadrant third molar extractions. The air dissection in our case was contained within the masticator and submandibular spaces, which acted as barriers preventing the air from breaching the buccopharyngeal fascia and retropharyngeal danger space. Additionally, the complete left maxillary sinus opacification suggests that the maxillary sinus functioned to absorb, decompress and contain a substantial portion of the positive pressure. The distribution of four sockets prevented the formation of a single, highly concentrated high-pressure gradient capable of dissecting into the deep cervical fascial pathways.

While patients undergoing third molar extractions routinely receive intravenous sedation, which may predispose them to nausea when compounded by the need for postoperative opioid analgesics, the risk of severe emesis is higher under general anesthesia. The use of volatile inhalational anesthetics are emetogenic agents that directly stimulate the central chemoreceptor trigger zone, contrasted by propofol, an agent with inherent antiemetic properties. Furthermore, the positive-pressure ventilation required during general anesthesia can cause inadvertent gastric insufflation, another trigger for the vomiting reflex.^17–19 The fact that our patient developed emesis that drove fascial air dissection despite undergoing intravenous sedation underscores the need to identify and preemptively treat high-risk individuals.

Beyond the anesthetic modality, patient-specific risk factors must be evaluated using validated assessment tools, such as the Apfel Simplified Risk Score. ²⁰ High-risk individuals include female patients, non-smokers, individuals with a documented history of motion sickness or previous postoperative nausea, and those who require postoperative opioid analgesics for pain management. When multiple risk factors are present, the administration of prophylactic antiemetics such as intravenous dexamethasone intraoperatively or ondansetron in the immediate perioperative phase is highly recommended to protect the integrity of the unhealed surgical sites.^21,22

Conclusion

This case underscores the continued relevance of subcutaneous emphysema as a rare postoperative complication. Clinicians should maintain a high index of suspicion for this condition in patients presenting with rapid postoperative swelling and crepitus, and early imaging should be utilized to distinguish it from angioedema, routine postoperative swelling and infection. To our knowledge, this represents the first reported case of subcutaneous emphysema following third molars extractions likely precipitated by postoperative nausea, retching and vomiting, highlighting the importance of considering prophylactic antiemetics in high-risk patients. Continued reporting of such atypical presentations is essential to advance public health and ensure clinical safety.