Ear, Nose, and Throat Procedures

Fig. 7.1

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)

Clinicians must also be familiar with sonographic evaluation of the airway. Air-tissue interface can help the operator identify relevant anatomy. In the mouth, air-tissue interface can be identified as a hyperechoic line which follows the curvature of the tongue (Fig. 7.2a) and as a hyperechoic line between the gum line/teeth and the cheek (Fig. 7.2b). In the neck, the interface is used to identify the trachea (Fig. 7.2c).

../images/323313_1_En_7_Chapter/323313_1_En_7_Fig2_HTML.png — Fig. 7.2

Mucosa and air interface. (a) Transcervical imaging of the oropharynx demonstrates the tongue and soft palate interface (asterisks). (b) Soft tissue imaging of the face demonstrates the cheek and gingiva interface (asterisks). (c) Airway imaging. The trachea is identified as a result of the mucosa-air interface in a supine patient. In all three images, the hyperechoic line between surfaces is accentuated by trapped air

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

The vast majority of etiologies behind swelling and/or discomfort of the head or neck include cellulitis, abscess, cyst, lymphadenopathy, or salivary gland swelling (Fig. 7.3). Patients who are found to have edema or swelling should undergo sonographic evaluation for anechoic fluid collections. As mentioned these patients should generally undergo aspiration or incision and drainage.

../images/323313_1_En_7_Chapter/323313_1_En_7_Fig3_HTML.png — Fig. 7.3

(a) Soft tissue swelling of the face with cobblestone appearance consistent with cellulitis. (b) Anechoic fluid collection from periapical dental abscess (asterisk). (c) Lymphadenitis (L) with echogenic hilum (x). (d) Salivary gland inflammation

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

As with evaluation of most superficial structures, the high-frequency (15–6 MHz) linear array probe should be used. Color Doppler can help evaluate for hyperemia and aid in the identification of surrounding neurovascular structures. Lidocaine with or without epinephrine should be readily available. Chlorhexidine, a sterile probe cover, and #11 blade scalpel or 18 or 20 gauge needle attached to a 10 mL syringe should also be available (Fig. 7.4).

../images/323313_1_En_7_Chapter/323313_1_En_7_Fig4_HTML.png — Fig. 7.4

Linear array transducer and other equipment for incision and drainage

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

The linear array transducer should be used to scan the area in question in both the sagittal and transverse planes; whenever possible, the patient’s contralateral side should be imaged for comparison. An anechoic fluid collection with echoic contents often with posterior acoustic enhancement is concerning for abscess. This should be distinguished from cellulitis, which can have a cobblestone appearance without fluid collections (Figs. 7.5 and 7.6). The physician should gently compress the affected area for squish sign, and color Doppler flow can be used to confirm the lack of vascularity within the cavity (Fig. 7.7). If a fluid collection is located, the boundaries, depth from the skin surface, and estimated size of the cavity should be noted. The relevant adjacent anatomy should be evaluated; and the physician should be mindful of the underlying structures in the neck which include the thyroid, parathyroid, trachea, and vasculature. When draining an abscess of the face, care must be taken to avoid the facial nerve and branches of the trigeminal nerve. When draining abscesses of the neck, care must be taken not to injure the underlying neurovascular structures, and special care must also be taken to remain superficial to the platysma.

../images/323313_1_En_7_Chapter/323313_1_En_7_Fig5_HTML.png — Fig. 7.5

(a) Soft tissue swelling with presence of cobblestone appearance consistent with cellulitis. (b) Soft tissue swelling with anechoic fluid collection (asterisk) suggesting abscess

../images/323313_1_En_7_Chapter/323313_1_En_7_Fig6_HTML.png — Fig. 7.6

B-mode image of anechoic facial abscess with posterior acoustic enhancement

../images/323313_1_En_7_Chapter/323313_1_En_7_Fig7_HTML.png — Fig. 7.7

On color Doppler, no flow noted within the abscess cavity; however, hyperemia is seen surrounding the abscess cavity

Once the abscess and relevant anatomy have been visualized and imaged in at least two planes, the affected area can be anesthetized. The cutaneous area should be cleansed with chlorhexidine. The probe should be covered with a tegaderm, and gel should be placed on top of the probe. Using an 18 or 20 gauge needle attached to a 10 mL syringe, advance the needle tip under ultrasound guidance using an in-plane approach (Fig. 7.8). If necessary, make a small incision using a #11 blade scalpel, and use blunt dissection to break up loculated fluid collections (Fig. 7.9a, b). Extensive abscesses may require irrigation with normal saline to aid in breakdown of loculations. Ultrasound should be used after drainage is complete to verify complete evacuation of the abscess cavity (Fig. 7.10).

../images/323313_1_En_7_Chapter/323313_1_En_7_Fig8_HTML.png — Fig. 7.8

Needle aspiration using in-plane approach

../images/323313_1_En_7_Chapter/323313_1_En_7_Fig9_HTML.png — Fig. 7.9

Ultrasound-guided incision and drainage. (a) Probe positioning for incision. (b) Probe positioning for drainage

../images/323313_1_En_7_Chapter/323313_1_En_7_Fig10_HTML.png — Fig. 7.10

(a) Anechoic abscess cavity (arrows) prior to incision and drainage. (b) Post incision and drainage image confirming abscess evacuation, collapsed abscess cavity (arrows)

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.

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