Novel Minimal Access Bone Anchored Hearing Implant Surgery and a New Surface Modified Titanium Implant, the Birmingham Experience

Single-Center Experience Evaluating Clinical Outcomes of a Novel-Guided Drill System for Percutaneous Bone-Anchored Hearing Implant

OBJECTIVE

Evaluate intraoperative and postoperative outcomes of a novel guided drill system for percutaneous bone-anchored hearing implants.

METHODS

Between January 2016 and February 2021, patients age ≥18 years deemed potential candidates for a bone-anchored hearing device, were formally assessed for candidacy and counseling. Those that qualified and opted to proceed were added to a prospectively maintained database, including demographic, clinical, and audiologic data. Intraoperative findings were reported, as were clinical outcomes at 7 days, 4 weeks, 3 months and 6 months postoperatively. The Holgers index was used to grade soft tissue reactions.

RESULTS

One hundred patients underwent the procedure. There were 56 women, and mean age was 54 years (18-84 yr). Ninety-six were done under local anesthetic. Mean surgical time was 13 minutes (9-27 min). No significant intraoperative events were noted. There were nine cases of implant loss, all in the first 50 cases. Mean duration of implant loss was 3.6 weeks (range, 2-5 wk). At the first postoperative visit, 82 had Holgers 0, 16 Holgers 1, 2 Holgers 2, and none Holgers 3. At the second postoperative visit, excluding the 9 with implant loss, 83 (91%) had Holgers 0, 6 (7%) Holgers 1, and 2 (2%) Holgers 2. None were Holgers 3.

CONCLUSIONS

The current study represents, to our knowledge, the largest series on the novel guided drill technique. Results show it is safe and efficient with low soft tissue complication rates. Drill bit design and technical modifications may have helped lower implant loss rate in this series over time.

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

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.

Comparison between linear incision and punch techniques for bone anchored hearing aid surgery

Objectives

To evaluate mean surgical time, incidence of soft tissue reactions, implant survival and intraoperative complications in both minimally invasive ponto surgery (MIPS) and the linear incision with tissue preservation technique (LT).

Methods

A retrospective review was carried out on 48 bone anchored hearing system (BAHS) patients between 2014 and 2019: 13 patients had undergone LT and formed one group, while 35 patients had undergone MIPS and formed the second group. Mean surgical time, intraoperative complications, implant loss and skin reaction were assessed at each post-operative examination. The Mann-Whitney U test was used for statistical analysis.

Results

The difference in the mean surgical time of 15 mins for MIPS and 36 mins for LT was statistically significant. No intraoperative complications were reported and implant survival was 100% in both groups. The incidence of adverse skin reactions was 7.7% for the LT group and 0% for the MIPS group at first follow-up examination.

Conclusions

Surgical mean time is shorter for MIPS, making this procedure more suitable for local anaesthesia and more cost effective. Moreover, both LT and MIPS demonstrate good surgical outcomes in terms of skin reactions according to Holgers score and equally excellent implant survival.

A Clinical Evaluation of Minimally Invasive Ponto Surgery With a Modified Drill System for Inserting Bone-Anchored Hearing Implants

OBJECTIVE

To compare 6-months outcomes of the modified minimally invasive Ponto surgery (m-MIPS) to both the linear incision technique with soft tissue preservation (LIT-TP), and original MIPS (o-MIPS) for inserting bone-anchored hearing implants (BAHIs).

STUDY DESIGN

Exploratory pilot study with one test group and two historical control groups.

SETTING

Tertiary referral center.

PATIENTS

In the test group, 24 patients (25 implants) were prospectively included. Each control group comprised 25 patients (25 implants) who participated in previously conducted clinical trials.

INTERVENTIONS

The test group received a BAHI using m-MIPS. The two control groups underwent surgery using the LIT-TP and o-MIPS, respectively.

MAIN OUTCOME MEASURES

Implant survival, implant stability, and surgery-related variables were compared between the test and control groups. Soft tissue status, skin sensibility, and subjective numbness were compared between m-MIPS and LIT-TP only.

RESULTS

Implant survival was comparable between m-MIPS and LIT-TP, whereas implant stability measurements were slightly lower for m-MIPS. M-MIPS resulted in comparable adverse skin reactions and skin sensibility, significantly reduced surgical time and slightly improved subjective numbness, compared with LIT-TP. Between m-MIPS and o-MIPS, no statistically significant differences in implant survival, implant stability and surgical time were observed.

CONCLUSIONS

A trend toward lower implant loss rates after m-MIPS was observed, when compared with o-MIPS. M-MIPS seems to be a good alternative to LIT-TP for inserting BAHIs, since most clinical outcomes were either comparable or slightly better for m-MIPS. Upon deciding on which technique to use, larger studies on implant survival should be performed. Furthermore, other aspects such as costs, training aspects and surgical experience should be evaluated.