Basics of cochlear implant surgery Roland Laszig Susan

Basics of cochlear implant surgery Roland Laszig, Susan Arndt Implant Center Freiburg Dept. of Otorhinolaryngology Chair: Univ. -Prof. Dr. med. Andreas Knopf University of Freiburg, Germany

Basic surgical steps • General anesthesia, head turned laterally and downwards • Facial nerve monitoring • Retroauricular access, short incision (“minimal access surgery”)

Basic surgical steps Soft tissue: • Acc. to N. Cohen: "keep a gentle touch" • delicate handling • 2 -layer approach • small incision

Macroscopic mastoidectomy: removing cortical bone, opening of antrum • from: Nelson "Temporal Bone Surgical Dissection Manual", House Ear Institute, USA

Prepairing the bony implant well macroscopically

Modified Cochlear Implant Fixation Using a Single Suture (Hassepass et al. 2011) • Bony canal in the posterior mastoid cavity • PDS-suture through the bone canal and posterior trough the periosteum

Use of microscope: further opening of antrum, identitifcation of incus (important landmark!)

Posterior tympanotomy

CI insertion • Cochleostomy • round window insertion

Cochleostomy or round window insertion? • Old discussion: • • • Franz et al. 1987: Surgical anatomy of the round window with special reference to cochlear implantation, Briggs et al. 2001: Surgical implications of perimodiolar cochlear implant electrode design: avoiding intracochlear damage and scala vestibuli insertion Li et al. 2007: Anatomy of the round window and hook region of the cochlea with implications for cochlear implantation and other endocochlear surgical procedures. • per definition: round window => scala tympani insertion (dislocation not excluded) • remove bony overhang • Sign. better results following scala tympani insertion (Aschendorff et al. 2007, Finley et al. 2008, Holden et al. 2013) • problem: trauma spiral lamina, modiolus, cochlear aqueduct (Hook region)

Cochleostomy Round window insertion

Electrode lead fixation? Risk: extrusion of array pull-out during measurements and closure Problem: in Contour electrodes stylet is removed, risk of tipfoldover Solution: utmost care for lead placement before and during closure, overhanging edges to securely place leads, fixation with clip/suture/cement

2 layer-closure: periosteal pocket and skin intracutanous resorbable suture