Transoral robotic surgery for the resection of parapharyngeal tumour: Our experience in ten patients

Abstract

Dear Editor, Treatment for parapharyngeal tumours involves surgery, and different surgical approaches have been reported in the literature, including the transcervical, transcervical-transparotid and transmandibular approaches.1–3 However, these invasive procedures had a risk of comorbidities and left a visible scar on the face or neck. The transoral approach among various conservative methods is under active research and clinical utilisation. Many studies have demonstrated the feasibility of transoral robotic surgery in the treatment of laryngopharyngeal tumours with excellent results in terms of oncologic radicality and functional preservation.4–6 Previous reports already showed the feasibility of transoral robotic surgery for the resection of parapharyngeal space tumour in selected cases.7,8 We recently refined the transoral extirpation of parapharyngeal tumours using the da Vinci robot system (Intuitive Surgical Inc., Sunnyvale, CA, USA). We used this approach alone or in combination with the transparotid approach depending on the localisation of the tumour. The purpose of this study was to analyse the validity of this technique. We performed transoral parapharyngeal tumour resection in 10 patients. Main clinical features are reported in Table 1. Patient ages ranged from 25 to 56 years (mean = 39.2). Pre-operative imaging studies evaluated the lesions of the patients (Fig. 1). They were followed up for a mean period of 20 months (range, 8–33) after the procedure. The operating room and da Vinci Robotic system were set up as described in a previous study.4–6 According to the dimension and localisation of the lesion, we classified surgical techniques into three classes: Type 1: Robotic transoral resection. This approach was used in three cases (patient 1, 8 and 9) of parapharyngeal tumour with limited dimension, which did not extend or push towards the stylomandibular tunnel (Fig. 2a). In these cases, a vertical incision was made on the mucosa covering the lesion (Fig. 2c). Then, the mass was evidenced and gently detached from the soft surrounding tissues without capsular interruption (Fig. 2d). Vascular structures were isolated and managed through vessel clipping or simple ligation (Fig. 2e). The incision was sutured using the robotic arms through simple ligation (Fig. 2f). Type 2: Robotic transoral resection with coblation using a coblator (Coblator II Surgery System, ArthroCare ENT, Austin, Texas, USA). This approach was used in cases (patient 2 and 7) of larger parapharyngeal tumours originated from the parapharyngeal space and pushed towards the stylomandibular tunnel (Fig. 3a). A vertical incision was made on the mucosa covering the lesion. Afterwards, the mass was evidenced and gently detached from the soft surrounding tissues without capsular interruption (Fig. 3a,d). In these cases, to complete the resection without risk of injury, the tumour capsule was incised and a coblator was inserted into the tumour (Fig. 3b,e). The volume of the mass was reduced, and the excision was completed transorally, according to the modalities of the Type 1 technique reported above (Fig. 3c,f). Coblation of the central portion allowed the surgeon to reduce the dimensions of the mass to obtain better control of the neurovascular structures. The reason why we used the coblator is to reduce the volume of the tumour mass. This instrument allowed a gentle debulking of the tumour inner mass. Furthermore, the small dimension of the instrument permitted controlling the movements of its sharp tip in all the phases of the procedure. Once the volume of the tumour is reduced, we could meticulously suture the capsule and completed the extra-capsular dissection without risk of tumour spillage. Type 3: Robotic transoral resection plus transparotid resection. This approach was used in five cases (patient 3, 4, 5, 6 and 10) of bilobed large tumours that originated from the deep lobe of the parotid gland and extended through the stylomandibular tunnel i