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.