Pseudoaneurysm following “routine” third molar extraction: a case report and review of the literature


Pseudoaneurysms are rare, life-threatening vascular lesions caused by damage to an arterial wall and have a high propensity for rupture and hemorrhage. The aim of this case report is to discuss the evaluation, diagnosis, and management of unusual bleeding following dental extractions in an otherwise healthy 17-year-old female. She presented post-operatively with facial swelling and bruising following outpatient extraction of third molars. Exploration of the surgical site revealed active bleeding that was unresponsive to pressure and application of hemostatic agents. Selective embolization was performed after a pseudoaneurysm of the inferior alveolar artery was identified, resulting in no further bleeding and return to baseline diet and activity. Any practitioner performing dental extractions who encounters unusual bleeding should be aware of this potentially fatal vascular lesion and its relevant treatment options. While surgical ligation is technically feasible, minimally invasive intravascular interventions provide a safe and effective method for management of this complication.


  • Third molar extractions may result in unusual episodes of post-operative bleeding.

  • Life-threatening pseudoaneurysms can arise from iatrogenic injuries.

  • Oral surgeons should be aware of this complication and possible treatment options.

  • Minimally invasive coil-embolization may be an option to manage this complication.


The extraction of third molars is one of the most common surgeries performed by oral and maxillofacial surgeons (OMFS) as well as general dental practitioners, with over 10 million impacted third molars extracted annually in the United States [ ]. The reported rate of complication ranges from 3.5 to 14.8% [ ]. The four most commonly reported post-operative complications of third molar extractions are alveolar osteitis, infection, bleeding, and paresthesia; less common complications include mandibular fractures, severe hemorrhage, and iatrogenic displacement of teeth and instruments [ ].

Clinically significant bleeding occurs in approximately 0.2–5.8% of cases and can be categorized into two groups: intra-operative and post-operative bleeding [ ]. Intra-operative bleeding is a rare occurrence and can be defined as bleeding that is greater than expected during a dental extraction, which may be secondary to an arteriovenous malformation [ ]. The more commonly encountered post-operative bleeding can be defined as bleeding after an extraction that meets at least one of the following four criteria: (1) persists for greater than 12 hours, (2) causes return to surgeon or presentation to an emergency department, (3) results in large hematoma or ecchymosis within the perioral soft tissues, or (4) requires transfusion.

Etiologies of post-operative bleeding can be divided into those related to the procedure and those related to the medical condition of the patient [ , ]. Procedure-related factors include tears to the surrounding soft tissues, injury to the cortical bone (either planned or iatrogenic), damage to the tooth blood supply, and increased vascularity in response to pre-existing chronic infection (e.g. granuloma). Hemorrhagic diatheses involving the quality or quantity of platelets or disorders of coagulopathy, as well as medical conditions that require patients to be on anticoagulant therapy also predispose patient to an increased risk of prolonged bleeding.

One unusual cause of post-operative bleeding is the formation of a pseudoaneurysm that results in uncontrollable post-operative bleeding. A pseudoaneurysm is a collection of blood that is contained within perivascular soft tissue. Whereas true aneurysms involve a segmental, full-thickness dilation of an intact blood vessel, pseudoaneurysms involve localized disruption of the arterial wall that results in a contained hematoma with a persistent connection to the arterial lumen ( Table 1 ) [ ]. Pseudoaneurysms are typically caused by trauma to a vessel; however, they can also be a result of regional inflammation or underlying vasculidities [ ]. We present a case of a pseudoaneurysm following the “routine” extraction of third molars that was treated with interventional vascular radiology.

Table 1
Comparison of aneurysm and pseudoaneurysm.
Vascular Injury Definition Clinical Work Up Treatment
Aneurysm 50% increase in the normal diameter of the artery resulting in weakening of the blood vessel wall
  • Comprehensive history and physical exam

  • •Duplex ultrasound

  • •CT/CT angiogram

  • •MR angiography

  • •Observation

  • •Repair is dependent on location: resection with interpositional grafting or endovascular repair

Pseudoaneurysm Arterial defect that becomes contained within the surrounding soft tissues
  • •Comprehensive history and physical exam

  • •Duplex ultrasound

  • •CT/CT angiogram

  • •Observation

  • •Ultrasound-guided compression

  • •Endovascular injection of hemostatic agent

Report of a Case

A 17-year-old female with no significant past medical history presented to the Oral and Maxillofacial Surgery outpatient clinic for extraction of her complete bony impacted third molars ( Fig. 1 ). The surgical extraction of the third molars was considered “routine” – extraction of the complete bony impacted mandibular third molars involved a distal “hockey stick” incision, raising of a full-thickness mucoperiosteal flap to uncover the crowns (which were noted to be lingually inclined), buccal troughing with a surgical handpiece under copious irrigation, and elevation with extraction without splitting of the tooth; the nerve was visualized and noted to be intact and there was no excessive bleeding at the time of the surgery and re-approximation of the soft tissues. The patient returned to the clinic 3 days later with complaints of right facial edema and ecchymosis, as well as pulsating pain, malaise, and subjective fever. Intraoral examination showed grossly inflamed soft tissue around the residual socket of extracted tooth #32 that was spontaneously bleeding and disproportionately tender to palpation. There was minimal floor of mouth elevation lingual to the residual alveolus. The sockets of teeth #1, 16, and 17 were unremarkable, with an examination consistent with routine healing. There were no neurosensory disturbances reported by the patient.

Fig. 1
Pre-extraction orthopantomogram (Panorex) demonstrating complete bony impacted third molars (teeth #1, 16, 17, 32). Drawn, for patient education, is the relationship of teeth to the maxillary sinus and mandibular canal.

Upon reflection of the mucoperiosteal flap of tooth #32, brisk bleeding was encountered. Multiple “liver clots” were found underneath the surrounding soft tissues and evacuated. The buccinator muscle was noted to be grossly ecchymotic; the lingual plate was noted to be grossly intact, with no perforation. No purulence was encountered. Once the base of the socket was cleared and the inferior alveolar artery was noted to be the source of bleeding, multiple attempts to control hemorrhaging with gelfoam, Surgicel, and Floseal with pressure were made to no avail. The decision was made to activate the emergency medical services to transfer the patient to an inpatient setting for additional work up and management. On admission, computed tomography angiography (CTA) with intravenous contrast of the maxillofacial complex demonstrated a peripherally enhanced fluid collection measuring 1.5 × 2.5 cm around the buccal and lingual surfaces of the mandibular body with cortical erosion of the medial surface of the right mandibular ramus and vascular blushing of the infeeding inferior alveolar artery ( Fig. 2 ). Interventional radiology (IR) was consulted for emergent intervention.

Aug 14, 2022 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Pseudoaneurysm following “routine” third molar extraction: a case report and review of the literature
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