Another use for Tisseel – plugging of the round window
Reviewed by Anand Kasbekar

After insertion of a cochlear implant electrode through the round window, there are several methods of sealing the perilymph leak and in my experience fascia (with varying amounts of attached muscle) seems to be most commonly used. Stephen O’Leary’s group in Melbourne have already shown us previously (in guinea pigs) that round window insertions led to a delayed hearing loss at 2KHz. In this article they demonstrate in 21 guinea pigs again (using ABR), that there is a difference in which material we use to plug the round window after electrode insertion. The materials tested were muscle, periosteum and fibrin glue. ABR were performed on the subjects up to 12 weeks post implantation and the guinea pig cochleas are submitted for histological examination. The study found that using muscle or periosteum (similar to fascia) causes a delayed rise in ABR threshold or hearing loss, mainly at 2kHz. Fibrin glue dissolves in two weeks and therefore it is thought causes a smaller tissue response and fibrosis and less disturbance of the cochlear mechanics. The paper goes on to discuss the similarities this process might have with otosclerosis. This work will certainly make me want to use fibrin glue for hearing preservation surgery and I think the next step is for a trial in humans to see if this effect is clinically significant.

The effect of round window sealants on delayed hearing loss in a guinea pig model of cochlear implantation.
Rowe D, Chambers S, Hampson A, et al.
OTOLOGY AND NEUROTOLOGY
2016;37(8):1024-31.