DS28 In search of salivation? Management of parotid duct injury following Mohs micrographic surgery

Abstract

Abstract Parotid duct injury is a rare complication of cutaneous surgery usually occurring after excision of deep infiltrating tumours on the cheek. The existing literature is limited to case reports. We present our experience of two cases encountered in our unit over the last 15 years. Our first patient was an 87-year-old man referred for Mohs excision of a biopsy-confirmed morphoeic basal cell carcinoma (BCC) on his right cheek. During tumour extirpation, it was necessary to sacrifice a short section of the parotid duct. This was confirmed by direct visualization of the duct and a visible salivary leak. Immediate referral was made to the plastic surgery department, who also noted ipsilateral weakness in the distribution of the buccal branch of the facial nerve. The parotid duct was repaired over a lacrimal stent secured to his buccal mucosa. The wound was reconstructed with a large rhombic transposition flap and the parotid gland infiltrated with botulinum toxin. Four weeks later, the salivary stent had spontaneously fallen out and fresh-looking saliva was noted emerging from the parotid ampulla. Our second patient was a 65-year-old man referred for Mohs excision of a 3-cm nodular BCC on the left cheek. During tumour extirpation, a short section of the parotid duct was resected, which was clearly visible in the Mohs layer. On this occasion, the patient was referred to colleagues in the maxillofacial surgery department who attended the dermatology surgical unit. Under local anaesthesia, the parotid duct was cannulated using an epidural catheter secured both intraorally and to the residual duct using an absorbable monofilament suture (intraoperative pictures will demonstrate the technique). The Mohs defect was reconstructed with a bilobed transposition flap. Hyoscine patches were supplied to help reduce salivary flow. Marked swelling of the parotid gland developed postoperatively, which settled without further intervention. After 4 weeks, the epidural catheter was removed, and saliva was noted to be flowing from the parotid ampulla. Weakness of the lip elevators was noted in keeping with facial nerve injury. Despite the infrequency of parotid duct injury, it is important that cutaneous surgeons/Mohs surgeons are aware of how to proceed in these cases. In cases where assistance is not available from other specialties, the technique could be undertaken by an appropriately trained dermatological surgeon/Mohs surgeon using local anaesthesia.