Liquid collection protocol
The procedure was performed under general anaesthesia. After cleaning and washing the ear canal with saline solution, each effusion was collected by aspiration with a 1.2 gauge suction cannula connected to a cell trap, following myringotomy. The glue was considered mucosal if it was thick, difficult to aspirate and stuck to the wall of the cell trap (19) (requiring micro forceps to collect the effusion if necessary). It was considered serous if the suction was easy and the collection was liquid and mobile in the cell trap.
The samples collected were immediately immersed in a container filled with ice to prevent protein denaturation by heat, and then transported immediately to the laboratory. Each mucoid effusion was separated into two samples, using micro scissors, and then placed in two cryotubes marked with the patient’s anonymised code. The thinner serous samples were divided into two cryotubes by pipette. No dilution was carried out at this stage. The samples had an average volume of 200µl. The cryotubes were frozen at -80°C.