Ex vivo Evaluation of a New Drill System for Placement of Percutaneous Bone Conduction Devices

Abstract

The procedure for installation of a percutaneous bone-conducting device has undergone significant improvements since its introduction 40 years ago. Today, the linear incision technique with tissue preservation (LITT-P) and the minimally invasive procedure (MIPS) are the most commonly used approaches. In both these techniques, a gradual increase of the osteotomy using a three-step drilling sequence is utilized, as this approach can allow a stepwise deepening and widening of the osteotomy in the mastoid and can prevent bone overheating. A new minimally invasive procedure (MONO) has been developed that allows an osteotomy to be performed and enables complete removal of the bone volume in one single drill step for a 4 mm implant using a novel parabolic twist drill. Here, the feasibility of the MONO procedure was qualitatively and quantitatively evaluated in terms of the dura response to drill trauma in comparison with the outcomes achieved with guide drills used for the LITT-P and MIPS techniques. Fresh frozen temporal bone from a human cadaver was subjected to penetration by three drills beyond the base of the mastoid bone to different depths. The sites were evaluated, and the damage to and possible penetration of the dura were determined. The results showed that for a drill depth exceeding mastoid bone thickness by not more than 1 mm, damage to the dura was limited or nonexistent, whereas for a drill depth exceeding bone thickness by 2 mm, damage increased, or the dura was penetrated. There was a trend toward more damage and penetration for both the round burr and MIPS guide drill compared with the MONO drill bit. From this experimental ex vivo study, it can be concluded that if the dura is encountered, the MONO system is not more inclined to penetrate the dura than the conventional LITT-P and MIPS systems.

Minimally invasive surgery as a new clinical standard for bone anchored hearing implants—real-world data from 10 years of follow-up and 228 surgeries

“…The surgical techniques for installation of the BAHS have evolved significantly in recent years, particularly with the introduction of minimally invasive techniques such as MIPS and MONO, where the drilling procedure and installation are performed via a cannula inserted in a 4–5 mm circular skin incision ( 9 , 10 , 13 ). Here, we report the surgical and postoperative outcomes of using these techniques in a large number of patients in comparison with the conventional linear incision tissue preservation technique, demonstrating favorable results of MIPS and MONO in terms of surgery time and postoperative complications.…”

“…The method has been technically evaluated ( 10 ) and verified in randomized controlled trials for both short and long term benefits ( 6 , 11 ). Further improvements were introduced by the MONO procedure, where the osteotomy is created using a one-step drill procedure, in contrast to the linear incision and MIPS techniques where a 3-step drilling procedure is employed ( 12 , 13 ). Due to the single drill step approach, the MONO procedure is intended for 4 mm implants and adult patients only.…”