Transoral robotic surgery for head and neck malignancies: Imaging features in presurgical workup

Abstract

The objective of this article was to review the indications for transoral robotic surgery (TORS) in head and neck malignancies. The role of imaging in patient selection will be specifically reviewed. TORS is a recently developed technique that allows minimally invasive surgeries to be performed in the head and neck. TORS has a role in the de‐escalation of oropharyngeal cancers, which allows for lower doses of chemoradiation therapy (this is a technique currently in clinical trials). Additionally, this technique allows for less invasive surgery and decreases associated complications. TORS can also be performed at other subsites. Cross‐sectional imaging has a prominent role to help identify suitable candidates for this type of surgery. This article will review important anatomy and staging related to TORS. Additionally, the key imaging features for patient selection (indications and contraindications) will be presented along with case illustrations.

Patient Selection for Transoral Robotic Surgery (TORS) in Oropharyngeal Squamous Cell Carcinoma

“…Triple modality therapy (surgery followed by postoperative chemoradiotherapy) is generally avoided if possible (indicated in the case of positive surgical margin or histopathologic extranodal extension (ENE)) 60 because of the associated excess morbidity compared to upfront chemoradiotherapy. 61 This is to say that the potential functional benefits of TORS are greatest among patients for whom complete surgical resection will result in a reduced radiation dose and will eliminate the need for adjuvant chemotherapy. TORS is unlikely to benefit patients whose disease dictates the need for chemotherapy and radiation regardless of the surgical outcome-specifically those patients for whom margin-negative resection is improbable or likelihood of ENE is high.…”

“…68 Early-stage tumors (T1 -less than or equal to 2 cm; T2greater than 2 cm but less than or equal to 4 cm) confined to the tonsillar fossa (Fig. 7) are very good candidates for TORS, 20,61 though larger tumors may also be successfully removed with TORS when exophytic. In appropriately selected patients, upfront TORS may reduce 44,69,70 or even eliminate the need for adjuvant therapy, as excellent oncologic outcomes have been achieved in this patient population with surgery alone.…”

Retropharyngeal Internal Carotid Artery Management in TORS Using Microvascular Reconstruction

“…Retropharyngeal internal carotid arteries are a relatively rare (incidence 2.6%–10%), but well‐described anatomic variant relevant to the transoral approach to extirpation of oropharyngeal cancers 1–3 . The presence of a retropharyngeal carotid artery is thought to be a risk factor for life‐threatening intraoperative vascular injury and/or perioperative cerebrovascular accident during oropharyngeal surgery 4–6 . Therefore, published guidelines for transoral robotic surgery (TORS) have generally regarded patients with retropharyngeal carotid arteries as contraindicated for surgery 4–6 …”

“…The presence of a retropharyngeal carotid artery is thought to be a risk factor for life‐threatening intraoperative vascular injury and/or perioperative cerebrovascular accident during oropharyngeal surgery 4–6 . Therefore, published guidelines for transoral robotic surgery (TORS) have generally regarded patients with retropharyngeal carotid arteries as contraindicated for surgery 4–6 …”

Muscle invasion in oropharyngeal carcinoma undergoing transoral robotic surgery

“…The mucosa and lymphatic tissues of the oropharynx are bound by musculature: palatine tonsils by the palatoglossus, palatopharyngeus, and the superior constrictors; lingual tonsil by the underlying intrinsic and extrinsic muscle of the tongue. 11,12 While deep muscular involvement (greater than 50% of deep tongue base musculature, prevertebral muscle involvement, deep pterygoid muscle involvement, extrinsic muscle involvement) has been described as a contraindication to TORS, [13][14][15] more superficial muscle involvement is commonly observed and readily resected. However, there is limited data regarding identifying the presence, or implication, of primary tumor invasion into the surrounding superficial muscles.…”