Long-Term Outcomes of the Minimally Invasive Ponto Surgery vs. Linear Incision Technique With Soft Tissue Preservation for Installation of Percutaneous Bone Conduction Devices

Abstract

Objective: Comparing the surgical outcomes of the Minimally Invasive Ponto Surgery (MIPS) technique with the linear incision technique with soft tissue preservation (LITT-P) for bone conduction devices after a follow-up of 22 months. Methods: In this multicenter randomized controlled trial, there was the inclusion of 64 adult patients eligible for unilateral surgery. There was 1:1 randomization to the MIPS (test) or the LITT-P (control) group. The primary outcome was an (adverse) soft tissue reaction. Secondary outcomes were pain, loss of sensibility, soft tissue height/overgrowth, skin sagging, implant loss, Implant Stability Quotient measurements, cosmetic scores, and quality of life questionnaires. Results: Sixty-three subjects were analyzed in the intention-to-treat population. No differences were found in the presence of (adverse) soft tissue reactions during complete follow-up. Also, there were no differences in pain, wound dehiscence, skin level, soft tissue overgrowth, and overall quality of life. Loss of sensibility (until 3-month post-surgery), cosmetic scores, and skin sagging outcomes were better in the MIPS group. The Implant Stability Quotient was higher after the LITT-P for different abutment lengths at various points of follow-up. Implant extrusion was nonsignificantly higher after the MIPS (15.2%) compared with LITT-P (3.3%). Conclusion: The long-term results show favorable outcomes for both techniques. The MIPS is a promising technique with some benefits over the LITT-P. Concerns regarding nonsignificantly higher implant loss may be overcome with future developments and research. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT02438618.

Keywords: MIPS; bone conduction device (BCD); hearing loss; minimally invasive ponto surgery; soft tissue reactions; surgical outcomes; surgical technique; tissue preservation.

Figure 1

Subject flow chart.

Figure 2

(A) Stacked bar chart for the highest observed Holgers Index scores during standard follow-up visits. In the right-sided figure (B), missing data were corrected with the last observation carried forward technique. Last visit (“2 years”) was at 22 months of follow-up.

Figure 3

Boxplots of ISQ measurements during standard follow-up visits with a subdivision for different abutment lengths. ISQ measurements are displayed for ISQ Low (A) en ISQ High (B). Asterisks (*) indicate a significant difference as calculated with a Mann–Whitney U-test (level of significance p < 0.05). Last visit (“2 years”) was at 22 months of follow-up.