Preclinical Study of a Minimally Invasive Cochlear Implant Device Based on 3D Printing of a Custom Guide.

Objective: The aim of this study is to test the feasibility of a custom 3D-printed guide for performing a minimally invasive cochleostomy for cochlear implantation.

Study design: Prospective performance study.

Setting: Secondary care. Department of Otolaryngology, Caen University Hospital.

Patients: Four unselected patients (eight temporal bones), donated to science.

Intervention: Therapeutic procedure with minimally invasive cochleostomy using a custom drill guide.

Main outcome measure: Comparing the difference in trajectory between the cochleostomy axis achieved with the guide and the ideal axis planned preoperatively. A mean accuracy of less than 0.5 mm at the cochlear target was considered satisfactory.The distance between the drilled axis and certain anatomical structures (facial nerve, external auditory meatus, stapes, and chorda tympani) was also measured.

Results: The average distance between the target and the planned target was 0.51 ± 0.21 mm. No critical structures were damaged.

Conclusion: The results of this feasibility study demonstrated that the precision of this guide was close to the target of less than 0.5 mm, with reassuring safety data regarding critical anatomical structures. It therefore seems worthwhile to pursue the development of the procedure with a larger-scale study, using more precise, high-performance software and cochlear implantation equipment and assessing the quality of electrode insertion.