Cochlear Implantation, Surgical Approach and Hearing Preservation
Preserving (low-frequency) residual hearing in cochlear implant (CI) patients is highly desirable for many reasons. Prentiss, Sykes, and Staecker (2010) evaluated low-frequency hearing preservation at 250, 500, and 750 Hz following cochlear implantation using a thin electrode array (with insertion depths of 20 to 28 mm). They concluded that "there is no clear relationship between insertion depth and amount of hearing preserved."
Santa Maria et al (2013) reported that 43 percent of their CI patients had complete hearing preservation at their first post-op evaluation. However, 24 months later, complete hearing preservation was present in only 25 percent of implanted ears, noting a "downward trend in hearing preservation" over time.
Havenith and colleagues (2013) compared "soft surgery" cochleostomy and round window CI electrode insertion techniques with regard to low frequency hearing preservation post CI. The authors used an electronic data base survey, which included 170 CI patients across 16 studies. In brief, the authors stated that "the available data do not show that there is a benefit of one surgical approach over the other regarding the preservation of residual hearing."
For More Information, References and Recommendations
Havenith S, Lammers MJW, Tange RA, Trabalzini F, Volpe AD, van der Heijden, GJMG., Grolman, W. (2013) Hearing Preservation Surgery—Cochleostomy or Round Window Approach? A Systematic Review. Otology & Neurotology 34(4):667-674.
Prentiss S, Sykes K, Staecker H. (2010) Partial Deafness Cochlear Implantation at the University of Kansas: Techniques and Outcomes. Journal of the American Academy of Audiology 21(3):197-203.
Santa Maria PL, Domville-Lewis C, Sucher CM, Chester-Browne R, Atlas MD. (2013) Hearing Preservation Surgery for Cochlear Implantation—Hearing and Quality of Life After 2 Years. Otology & Neurotology 34(3): 526-531.