Traumatic retropharyngeal hematoma successfully treated with n-butyl cyanoacrylate transarterial embolization: A case report and literature review

Abstract

Traumatic retropharyngeal hematoma (RPH) is a rare but potentially life-threatening condition; in fact, rapid hematoma expansion may lead to acute airway compromise. Although conservative management is often selected, prompt identification of active bleeding and appropriate intervention are crucial. Transarterial embolization (TAE) has recently emerged as a viable therapeutic option, particularly in cases with contrast extravasation on contrast-enhanced computed tomography (CT). We report a case of a 70-year-old man who developed traumatic RPH after a blunt head and neck injury from a fall. Contrast-enhanced CT revealed a retropharyngeal hematoma with active contrast extravasation along the anterior aspect of the lower cervical vertebrae. Angiography identified the bleeding source as the ascending cervical artery arising from the thyrocervical trunk. TAE was successfully performed using a combination of 25% n-butyl cyanoacrylate (NBCA) and coils. Hemostasis was achieved without ischemic complications. Although delayed airway compromise required temporary mechanical ventilation, follow-up imaging confirmed resolution of active bleeding and gradual hematoma reduction, and the patient recovered without rebleeding. TAE using NBCA can be an effective and rapid hemostatic strategy for traumatic RPH with active extravasation. Careful embolic material selection and meticulous attention to the complex vascular anatomy of the head and neck are essential to avoid complications. Furthermore, careful evaluation of the retropharyngeal space and contrast-enhanced CT are critical for timely diagnosis and treatment decision-making. This report underscores the potential role of NBCA-based embolization as a life-saving option in selected traumatic RPH cases.

Introduction

Traumatic retropharyngeal hematoma (RPH) is an uncommon condition that can occur following head and neck trauma. Notably, it carries a significant airway compromise risk when the hematoma expands rapidly [1,2]. Although conservative management, including airway protection, is generally the first-line approach, transarterial embolization (TAE) has been reported as an effective option in cases exhibiting contrast extravasation on contrast-enhanced computed tomography (CT) [3]. Additionally, this entity is often overlooked on routine imaging studies [4], and delayed recognition may influence both treatment decisions and clinical outcomes.

In this report, we describe a case of traumatic RPH that developed after a blunt head and neck injury and was successfully treated with TAE using n-butyl cyanoacrylate (NBCA). We discussed the selection of embolic material and the importance of imaging in guiding timely treatment decisions.

Case presentation

A 70-year-old man fell backward from a stepladder while working at heights and sustained an occipital head injury. He was transported to a referring hospital, where a C5 spinous process fracture and occipital contusion were diagnosed. A mediastinal mass was incidentally noted on chest CT, and he was referred to our hospital on the following day for further evaluation. The medical history was notable for atrial fibrillation, and edoxaban (Lixiana®) had been prescribed at 60 mg/day. On physical examination, extremity numbness was observed, raising suspicion of central cord syndrome; nevertheless, no clinical findings suggested airway compromise, including stridor or impaired oxygenation. After reassessment of the imaging studies obtained at the referring hospital, the retropharyngeal space measured 23 mm and 26 mm at the C2 and C6 levels, respectively. Therefore, RPH was suspected, and contrast-enhanced CT was subsequently performed. Contrast-enhanced CT demonstrated an RPH with active contrast extravasation along the anterior aspect of the C6–Th1 vertebral body (Fig. 1), and the patient was urgently referred to our department. Angiography demonstrated contrast extravasation from the thyrocervical trunk, a branch of the left subclavian artery, and TAE was subsequently performed. The procedure was carried out under local anesthesia.

Fig. 1.

CT images. (A–C) Sagittal views. (A) A high-attenuation mass lesion is present in the retropharyngeal space anterior to the cervical and upper thoracic spine (black arrowhead). (B) A fracture of the C5 spinous process is noted (black arrowhead). (C) Contrast-enhanced CT shows extravasation of contrast material anterior to the vertebral bodies from C6–T1 (black arrowhead). (D) Coronal contrast-enhanced CT demonstrates contrast extravasation anterior to the vertebral bodies at the C6–T1 level (black arrowhead).

A 6-Fr Axcelguide guiding catheter (Medikit, Tokyo, Japan) was introduced via the right femoral artery and advanced to the left subclavian artery, followed by angiographic evaluation. Angiography revealed active contrast extravasation into the retropharyngeal space from the ascending cervical artery arising from the thyrocervical trunk. A Phenom 17 microcatheter (preshaped 45°, Medtronic, USA) was advanced close to the bleeding point using a CHIKAI 14 guidewire (Asahi Intecc, Aichi, Japan). Embolization was performed with 25% n-butyl cyanoacrylate (NBCA; Histoacryl, B. Braun, Germany), prepared by mixing NBCA and Lipiodol (Guerbet, France) at a ratio of 0.5 mL to 1.5 mL. Subsequent angiography of the left subclavian artery showed minimal residual contrast extravasation. The microcatheter was repositioned to the same site, and additional embolization was performed using Numen (1.5 mm × 4 cm × 2; 3.0 mm × 6 cm × 2; Medtronic, USA) and ED (3 mm × 6 cm; 2 mm × 8 cm; Kaneka, Japan) coils (Fig. 2). Final angiography confirmed complete resolution of contrast extravasation. Left vertebral artery angiography showed normal opacification of the intracranial arteries, and the procedure was completed.

Fig. 2.

Angiographic images. (A, B) Contrast medium is injected into the ascending cervical artery, a branch of the thyrocervical trunk, with extravasation of contrast material noted. (A) Anteroposterior view; (B) oblique view. (C) Following the injection of n-butyl cyanoacrylate (NBCA), the NBCA cast is present. (D) After additional coil embolization. The arrowhead indicates NBCA, and the arrow indicates the coil.

After the procedure, the patient was managed in the intensive care unit. Later the same day, paradoxical breathing developed, and oral intubation with mechanical ventilation was initiated. Contrast-enhanced CT performed the following day demonstrated contrast extravasation resolution, with no evidence of hematoma expansion. Heparin therapy was initiated on hospital day 3, and subsequent contrast-enhanced CT exhibited no rebleeding or hematoma enlargement signs. Anticoagulation was later transitioned to oral therapy, and the patient was successfully extubated on hospital day 10. The RPH gradually decreased in size, and the patient was transferred to another hospital for rehabilitation on hospital day 33.

Discussion

The retropharyngeal space is an anatomic compartment bounded anteriorly, laterally, and posteriorly by the buccopharyngeal fascia, carotid sheath, and prevertebral fascia, respectively, extending from the skull base to the upper thoracic spine [5]. Traumatic RPH is a relatively rare condition; nonetheless, it carries an upper airway obstruction risk due to rapid hematoma expansion, requiring prompt diagnosis, airway management, and bleeding source assessment [1,2]. RPH most commonly develops within 24 h after injury and may occur even after minor trauma. Previous studies have demonstrated that its occurrence does not necessarily correlate with antithrombotic agent use [2]. Conservative management is generally the initial treatment approach; nevertheless, surgical drainage or transcatheter arterial embolization (TAE) may be selected in cases of rapid hematoma progression [1]. With recent advances in endovascular devices, an increasing number of case reports have described the use of TAE for traumatic RPH. Including the present case, 9 reported cases of traumatic RPH treated with TAE have been published [3,[6], [7], [8], [9], [10], [11], [12], [13]] (Table 1). In 8 of these cases, contrast-enhanced CT demonstrated active contrast extravasation, and the bleeding source most frequently originated from branches of the thyrocervical trunk. Airway protection was required in several cases. Notably, a substantial proportion of patients did not have associated intracranial or spinal injuries, which warrants particular clinical attention.

Table 1.

Published cases of transarterial embolization for traumatic retropharyngeal hematoma.

	Age/Sex	Mechanism of injury	Cervical/spinal/ intracranial injuries	Extravasation	Vascular sources	Embolic material	Method of airway management
Velde et al. [6]	84/F	Fall from height	NA	NA	Thyrocervical trunk	PVA	Oral intubation
Sheah et al. [7]	90/M	Self-fall	None	Yes	Small branch artery of vertebral artery	PVA	Oral intubation
Jakanani et al. [8]	65/F	Fall from height	C5 Vertebral body fracture	Yes	Thyrocervical trunk	Coils	Oral intubation
Caloggero et al. [9]	80/M	Self-fall	None	Yes	Thyrocervical trunk	NA	Oral intubation
Kudo et al. [10]	83/F	Traffic accident	C4-5dislocation, subarachnoid hemorrhage	Yes	Vertebral artery	NA	Oral intubation
Seunghan et al. [11]	55/M	Traffic accident	None	Yes	Thyrocervical trunk	PVA	Oral intubation
Iida et al. [12]	79/M	Fall from height	C3 cervical fracture, cervical spinous process fracture	Yes	Thyrocervical trunk	Coils	Emergency tracheotomy
Sugiura et al. [13]	88/F	Self-fall	None	Yes	Thyrocervical trunk	Coils	No intubation
Sakuma et al. [3]	78/M	Self-fall	None	Yes	Thyrocervical trunk	Coils, gelatin sponge	No intubation
our case	70/M	Fall from height	C5 spinous process fracture with central cord syndrome	Yes	Thyrocervical trunk	NBCA, coils	Oral intubation

F, female; M, male; NA, not available; PVA, polyvinyl alcohol; NBCA, n-butyl-2-cyanoacrylate

NBCA was approved for expanded use as an embolic agent in Japan in 2022 and has since become available for procedures involving the head and neck as well as the brain and spinal cord [14]. NBCA rapidly polymerizes upon contact with plasma water, and its polymerization time and penetration distance can be adjusted by altering the mixing ratio with lipiodol. Previous reports have indicated that feeding artery trapping using NBCA is effective in situations requiring rapid hemostasis or in cases in which coils or gelatin sponge embolization may be less effective, such as in patients with impaired coagulation [14]. When NBCA is used in the head and neck region, particular attention must be paid to potential reflux into neurovascular branches and dangerous anastomoses. Importantly, the thyrocervical trunk has potential anastomotic connections with the vertebral artery [15]. Here, because the microcatheter tip could not be advanced sufficiently close to the bleeding point, a 25% NBCA mixture was selected to allow distal delivery of the embolic agent while minimizing the risk of unintended migration into dangerous anastomoses. In previously reported cases using NBCA for traumatic RPH, detailed discussions regarding concentration selection and the risk of migration into the vertebral artery have been limited [16]. Therefore, the choice of NBCA concentration and injection technique should be carefully determined and performed by experienced operators. Furthermore, prior guidelines have suggested that liquid embolic agents may be more effective when combined with mechanical embolic materials, such as coils [17]. Accordingly, the embolization strategy adopted in the present case appears to have been appropriate.

The retropharyngeal space is easily overlooked during routine CT interpretation, particularly on imaging studies not primarily focused on the head and neck; moreover, several misinterpretation cases have been reported in the literature [4]. Therefore, careful evaluation of the retropharyngeal space is essential in patients with traumatic injuries. In the initial RPH diagnosis, non-contrast CT alone may be insufficient to assess soft-tissue hematoma and vascular injury, whereas contrast extravasation confirmation on contrast-enhanced CT is useful for determining the indication for therapeutic intervention. In most previously reported cases in which TAE was performed, contrast-enhanced CT demonstrated active contrast extravasation, underscoring its value as an indicator of ongoing bleeding and hematoma progression, as well as a guide for treatment selection. The normal anteroposterior thickness of the retropharyngeal space on cervical CT has been reported to range from approximately 1–7 mm and 9–22 mm at the levels of the C2 vertebral body and C6, respectively [18]. In the present case, the retropharyngeal space exceeded these normal ranges at both levels, providing sufficient radiologic evidence to suspect RPH. Paradoxical breathing that developed after the procedure was considered to be caused by progressive soft-tissue swelling surrounding the hematoma in the retropharyngeal space. Such swelling can exacerbate airway narrowing even after successful hemostasis; therefore, temporary airway protection with mechanical ventilation was required.

Based on this case, TAE using NBCA can be considered a potential treatment option for traumatic RPH. When using NBCA, the indication and procedural approach warrant careful consideration, particularly given the complex head and neck vascular anatomy, including potentially dangerous anastomoses and neural supply vessels. This case provides practical insight into NBCA use and highlights the importance of appropriate imaging evaluation in guiding therapeutic decision-making. Further cases are needed to better define the role of NBCA-based embolization in this rare but potentially life-threatening condition.

Conclusion

TAE using NBCA was effective for the treatment of RPH in this case. While NBCA may be a helpful embolic agent in selected situations, its use in the head and neck region requires careful individual assessment due to anatomical considerations. Furthermore, imaging findings are essential for determining treatment indications for RPH, and evaluation, including contrast-enhanced CT, can aid in treatment planning. This case illustrates the use of NBCA and the role of imaging evaluation in guiding therapeutic intervention.

Patient consent

Written informed consent was obtained from the patient for publication of this case report and any accompanying images.