Robot‐assisted submandibular gland resection via retroauricular approaches: Does the end justify the means?

I have read with interest the article titled ‘‘Feasibility of Robot-Assisted Submandibular Gland Resection via Retroauricular Approach: Preliminary Results’’ published in The Laryngoscope. This article describes an innovative technique for submandibulectomy through a retroauricular incision with robotic assistance. This approach is one of other minimally invasive procedures recently described for access to the submandibular gland, along with the transoral approach for functional and inflammatory diseases, and a retroauricular approach for a small (0.5 cm) pleomorphic adenoma. The current authors report on five cases of pleomorphic adenoma resected through a retroauricular incision with robotic assistance. The authors report no postoperative complications such as paresis or paralysis of the marginal mandibular branch of the facial nerve or of the hypoglossal nerve, no lingual nerve lesions, and no hematoma or seroma. The average follow-up was 5 months (range, 3–8 months), with no recurrence of the pleomorphic adenoma. This study does raise several questions from both a surgical standpoint and tumor control, however. The aim of this surgical approach is primarily to hide the scar in the area behind the ear in or near the hairline. This requires an incision length of 8 cm and the raising of a large subplatysmal flap for access. One could raise the question of the esthetic advantage of an 8-cm incision versus a 4or 5-cm incision hidden in a submandibular crease. The raising of the large flap exposes the patient to complications such as hematoma or seroma, even though the authors had no such problem in this small series of patients. Patient satisfaction as a goal is laudable, but patient satisfaction for this approach needs to be compared with patient satisfaction after the traditional open surgery, which in my experience is often also very high. Does satisfaction with the scar justify this wide and remote-access approach? The submandibular region is rich in major nerves. The marginal mandibular branch of the facial nerve runs just deep to the platysma along the superior (or anterior) aspect of the gland, lateral to the facial vein and artery, and its preservation is generally obtained by careful dissection, eventually just under the level of the capsule of the gland, as performed by the authors in the present study. Several authors recommend systematic identification of the nerve to optimize its preservation. To optimize nerve preservation, some surgeons even use neuromonitoring. The use of monopolar cautery or the harmonic scalpel for the dissection of the superior portion of the gland, as described by the authors, may expose this nerve to excessive thermal damage. The same can be said for the lingual nerve along the deep aspect of the gland and the hypoglossal nerve caudally. The authors even admit to having replaced monopolar cautery by the harmonic scalpel to avoid thermal damage to these nerves. Studies on a porcine model have shown that temperatures at the tip of a monopolar cautery device can attain 79 C and those at the tip of the harmonic scalpel 48 C after just 5 seconds. With increasing length of application, temperatures as high as 100 C can be obtained with monopolar cautery and 71 C with the harmonic scalpel. Temperatures above 42 C have been shown to damage cell membranes and denature proteins. Furthermore, a cool-down period of up to 1 minute may be necessary for the tip of the harmonic scalpel to decrease below 42 C. Thus, in my opinion, even the harmonic scalpel should be used with extreme caution for tumors arising at the superior aspect of the gland, near the marginal mandibular branch of the facial nerve, or for posterior-inferior lesions near the lingual and hypoglossal nerves. Several remarks can be made concerning the risk of tumor recurrence using this technique. Submandibular gland tumors are not as frequent as parotid gland tumors, and only 57% of submandibular gland tumors are benign. Pleomorphic adenomas are surrounded by a pseudocapsule, beyond which there are numerous microscopic extensions of the tumor, or ‘‘pseudopods,’’ with microscopic foci disseminated around the periphery of the main tumor. Although it appears macroscopically encapsulated, if a surrounding cuff of normal tissue is not removed along with the tumor, the risk of recurrence is high. This is one reason surgeons have avoided simple enucleation of these tumors, fearing an increase in local recurrence. Consequently, the treatment of choice is excision of tumor with a surrounding cuff of normal tissue, and a benign neoplasm arising in the submandibular gland can be resected through a simple excision of the gland itself. Some have reported success with a local excision with closer, but tumor-free, margins and preservation of the remaining gland. They observed no tumor recurrence, but the cohort was relatively small (20 patients) with a limited median follow-up (36 months). Several hypotheses explaining recurrences of pleomorphic adenomas have been proposed. Underestimated tumor spillage, incomplete excision, and violation of the pseudocapsule are considered the only proven reasons contributing to recurrent disease. Such recurrences