New Developments in Surgery for Malignant Salivary Gland Tumors

Abstract

AbstractMalignant salivary gland tumors (MSGTs) are of key interest for head and neck surgeons since surgery with adjuvant radiotherapy is considered the treatment of choice in most patients. In this respect, recently, interesting developments in ablative and reconstructive procedures have been proposed. Regarding the ablative part, transoral surgery, both with laser (transoral laser microsurgery or TLM) and robot (transoral robotic surgery or TORS) is increasingly used as a less invasive surgical treatment of malignant minor salivary gland tumors (MiSGMT) of the oropharynx, larynx and hypopharynx, with short-term follow-up data demonstrating feasibility, low morbidity and good oncological outcomes in combination with better functional results compared to open surgical approaches. As such, in selected patients, transoral endoscopic head and neck surgery can nowadays be considered a valuable component in the multidisciplinary management of MiSGMTs, and its possible use should be considered. For selected naso-ethmoidal MiSGMTs, especially adenoid cystic carcinoma of the ethmoid, small case series have supported the use of endoscopic transnasal surgery. Similarly, it has been shown that MiSGMTs localized in the nasopharynx without involvement of the internal carotid artery and minimal extension to the skull base can be effectively managed with transnasal endoscopic surgery. For MiSGMTs arising in the upper jaw, requiring maxillectomy, endoscopic approaches are also increasingly used in combination with and preceding the classical open approach maxillectomy techniques. Before the en bloc resection, the retromaxillary and infratemporal tumoral extension is controlled endoscopically and the pterygoid plates are cut superiorly. All this facilitates a clean “delivery” of the resected specimen with improved margin control. Regarding the reconstructive part, mainly new developments in reconstruction following radical parotidectomy have emerged. Common approaches to midface reanimation are the use of static slings, temporalis myoplasty, and innervated free muscle transfers (most often the gracilis muscle). Additionally, fasciocutaneous flaps (e.g. anterolateral thigh or ALT flap) are routinely used for skin and soft tissue replacement, while reconstruction of the facial nerve is commonly performed with free nerve cable grafting, which is associated with development of troublesome synkinesis and slow recovery of nerve function. New reconstructive techniques include a combination of masseteric nerve transfer to the buccal branch of the facial nerve with cable grafting of the remaining facial nerve defects, which minimizes synkinesis with fast return of oral commissure movement. Moreover, the use of vascularized nerve transfers, such as ALT with the lateral femoral cutaneous nerve and deep motor branch of the femoral nerve to vastus lateralis, are claimed to improve functional facial recovery outcomes when compared to free nerve grafts. Recently, new free flaps were described which are suitable for single stage reconstruction of complex defects after radical parotidectomy. These include the ALT with dual chimeric innervated vastus lateralis free flap which is suitable for both cutaneous reconstruction and dynamic reanimation of the midface after resection of the peripheral facial nerve branches and the thoracodorsal artery perforator and nerve flap (TAPN) flap, which allows for skin or soft tissue reconstruction in combination with facial nerve reconstruction from trunk to 4–6 distal branches. Although many of these new reconstructive approaches are promising, future comparative research is necessary in order to identify the most optimal reconstructive techniques in relation with specific indications, potentially allowing for future evidence-based patient-tailored reconstructive approaches.