Parapharyngeal Space Tumors

Abstract

In parapharyngeal space dissection, significant complications such as dysphagia and carotid artery rupture have been reported. In order to safely resect tumors located in the narrow parapharyngeal space, indocyanine green (ICG) fluorescence imaging for navigation surgery is proposed recently. In the following case study, the usefulness of ICG fluorescent image-guided surgery for parapharyngeal space tumors has been demonstrated. Initially, 0.5 mg/kg of ICG was injected via the cephalic vein. Observation of the fluorescent image was conducted with HEMS (Hyper Eye Medical System) between 5 and 30 min after the initial injection. At first, the position of the tumor was marked over pharyngeal mucosa according to ICG fluorescence imaging with HEMS. The submucosal tumor obscured fascia was confirmed under HEMS imaging and then resected completely. As a result, all tumors displayed bright fluorescence emissions that contrasted clearly with the surrounding normal structures. Even with the submucosal tumor covered with and obscured by fascia, the tumor could be clearly observed under HEMS imaging. Tumors located behind the carotid artery and lower cranial nerves also displayed bright fluorescent emissions and could be clearly detected. As a result, the tumor could be completely resected safely and noninvasively to preserve pharyngeal functions. In conclusion, ICG fluorescence imaging is effective for the detection and resection of the parapharyngeal space tumors while preserving functions.