Transoral Robotic Surgery for Parapharyngeal Space Masses: Indications and Results

Introduction: Transoral excision of parapharyngeal space (PPS) masses has historically been viewed with caution due to the lack of proximal vascular control and the limited access. Transoral Robotic Surgery (TORS) has emerged as an effective technique for selected parapharyngeal space masses. O’Malley and Weinstein and associates reported the first series of 10 patients treated with TORS for PPS masses in 2010 and described the technique and suggested indications and contraindications for the technique. Transoral surgery potentially avoids several complications associated with the open approaches. Methods: The University of Pennsylvania experience with PPS tumors was reviewed by searching the surgical database between 2008 and 2011. Patients who had Transoral Robotic Surgery were included in this series. Records were reviewed for radiographic findings, histopathology, surgical findings, and complications. Patients who had oropharyngeal carcinoma and/or retropharyngeal node metastasis from oropharyngeal carcinoma were excluded. Results: Transoral Robotic Surgery was used in 26 patients with parapharyngeal space masses. There were 20 benign lesions and 6 malignant lesions. Salivary gland tumors comprised the majority (15) of the patients: pleomorphic adenoma (13), monomorphic adenoma (1), and carcinoma ex-pleomorphic adenoma (1). The other malignancies included metastatic thyroid cancer (2), lymphoma (2), and melanoma (1). The other benign lesions were schwannoma (2), cysts (2), hemangioma (1), and spindle cell lesion (1). In the salivary gland group, OR time decreased over the course of the series. In the first seven patients, one was converted to an open approach; in the last eight patients, no conversions occurred. Average length of hospital stay has been reduced from 3.5 days to 2.25 days. Average total surgical time has been reduced from 211 minutes to 159 minutes. Complications occurred in 7.7% of patients and were limited to two pharyngeal dehiscences. Interestingly, we have not seen first bite syndrome in this group of patients. Conclusions: Transoral Robotic Surgery appears to increase the safety and feasibility of resection of a variety of parapharyngeal space lesions. The most common indication has been benign tumors of minor salivary glands. Complications have been uncommon, and this approach avoids the morbidity of external approaches. We find it particularly interesting that first bite syndrome has not occurred in this series. Radiographic evaluation and adherence to key surgical steps are critical in this paradigm. The lack of first bite syndrome supports the theory that avoidance of external approaches seems to avoid this rather troublesome complication. We currently do not advise TORS for poststyloid lesions or dumbbell lesions of the parotid gland.