Anatomy of the lateral neck (TC thyroid cartilage, CB carotid bifurcation, CB–Go carotid bifurcation–gonion, CB–ITC carotid bifurcation–isthmus of thyroid cartilage, CCA common carotid artery, ECA external carotid artery, ICA internal carotid artery, STA superior thyroid artery, LA lingual artery). (Reproduced from Topography of carotid bifurcation: considerations for neck examination. Surg Radiol Anat. 2008;30:383–387-p. 384)
Physical examination findings of head and neck swelling are not reliable, whereas sonographic evaluation purports a sensitivity >90% and specificity >80% [1]. Clinicians performing cutaneous procedures of the head and neck should use ultrasound to increase success rates and minimize complications.
Indications
Contraindications
Head and neck infections (dental infections, facial infections, peritonsillar abscess, etc.) can create direct or indirect airway compression. As a result, the patient’s airway should be assessed prior to starting the procedure. Patients in whom airway obstruction or airway compromise is deemed a risk factor should not undergo bedside drainage, and surgical consultation should be considered.
Equipment/Probe Selection
Preparation/Preprocedural Evaluation
For cutaneous procedures of the head and neck, the gurney should be at a height comfortable for the physician. The patient’s head should be comfortably turned to the contralateral side, and the neck should be extended to maximize access to the affected area. Topical anesthetic, such as lidocaine-epinephrine-tetracaine gel, can be used over the affected area to minimize discomfort. In certain scenarios, clinicians may choose to provide anxiolysis with benzodiazepines or systemic pain control with a short-acting narcotic. Prior to the procedure, depth of the abscess cavity from the surface of the skin, size of the abscess, and surrounding structures should be evaluated using ultrasound. Color Doppler should be used to identify adjacent vessels which should be avoided during the procedure.
Procedure
Complications
Injury to the surrounding neurovascular structures is a complication associated with head and neck cutaneous procedures. Additionally, lymph nodes may be difficult to distinguish from an abscess. Color Doppler can aid in the identification of vascular structures and lymph nodes. In addition, ultrasound should be used to verify complete evacuation of the abscess cavity. A partially drained abscess may result in the need for further intervention in the future.
Pearls/Pitfalls
- 1.
Injury to surrounding neurovascular structures can be avoided by utilizing color Doppler during the initial evaluation and performing the procedure under ultrasound guidance.
- 2.
Purulent material in the abscess cavity may appear isoechoic. For this reason, any findings should be compared to the contralateral side, color Doppler can be used to demonstrate hyperemic glands or nodes, and compression can help demonstrate abscess content motion.
- 3.
The use of 18 gauge needles is preferred as purulent material may be difficult to aspirate through smaller caliber needles.
- 4.
If purulent material is too viscous to aspirate, a #11 blade scalpel can be used to create a small puncture sufficient to allow for drainage.
- 5.
Use gray-scale imaging and color Doppler imaging to evaluate for necrotic lymph nodes and glands.
- 6.
In-plane approach is recommended while performing needle aspiration.
Integration into Clinical Practice
Physical examination of cutaneous swelling of the head and neck has poor diagnostic utility, whereas ultrasound has a sensitivity >90%. Ultrasound-guided incision and drainage of head and neck abscesses can provide definitive treatment. Furthermore, ultrasound-guided drainage can help prevent the occurrence of common complications, including injury to the surrounding neurovascular structures.
Evidence
High-resolution ultrasound provides a very high sensitivity (96%) and specificity (82%) for identification of purulent collections in evaluation of head and neck swelling [1]. Ultrasound-guided fine needle aspiration has a sensitivity of 89–98% and specificity of 95–98% in the differentiation of neck masses [4]. Yusa et al. described the utility of ultrasound guidance for draining deep face and neck abscesses. In addition, ultrasound guidance has been shown to be helpful in the drainage of submasseteric space abscess and needle aspiration of lateral masticator space [5, 6].
Key Points
Ultrasound-guided aspiration of cutaneous swelling of the head and neck will increase success rates, decrease complications, and as a result improve patient care and experience.
Hand dexterity and sonographic needle guidance skills are required and can easily be cultivated with practice.