Cochlear Implant Fixation Techniques: A Systematic Review of the Literature

OBJECTIVE: Given the lack of consensus on fixation techniques of the cochlear implant, this review aims to create an up-to-date overview of intra- and postoperative complications, focusing on migration of the internal receiver/stimulator (R/S) device and the electrode array. DATA SOURCES: On June 29, 2020 we conducted a search in PubMed, Embase, Cochrane, Web of Science, and CINAHL. Keywords were "Cochlear implant," "complication," "migration," and synonyms. STUDY SELECTION: Studies were considered if: 1) the adult study population consisted of ≥ 10 patients, 2) the R/S device was fixated using the bony well or tight subperiostal pocket technique without bone-anchoring sutures or screws on the implant, and 3) migration of the R/S device or displacement of the electrode array were described as outcomes. DATA EXTRACTION: Study characteristics, interventions, follow-up, and outcomes were extracted. For critical appraisal, an adapted version of the Newcastle-Ottawa quality assessment scale for cohort studies was used. DATA SYNTHESIS: Seven studies were included (n = 430 patients). Migration of the R/S device was reported by three studies. Two studies applying the tight pocket technique reported migration rates ranging from 9.0 to 69.2%. One study using the bony bed technique reported migration of 100%, with an average of 2.5 mm. All studies lacked the required standard for comparability, assessment of outcome, and follow-up. CONCLUSIONS AND RELEVANCE: There is currently no evidence of a difference between the bony bed- and tight pocket fixation technique, regarding migration of the R/S device or the electrode array, in adult patients

Long-Term Results of the Linear Incision Technique With Tissue Reduction Versus Tissue Preservation for Inserting Bone-Anchored Hearing Implants:The Ongoing Optimization in Bone Implant Surgery

Objective: To compare the long-term outcomes of the linear incision technique with tissue reduction (LIT-TR) and the linear incision technique with tissue preservation (LIT-TP) for inserting bone-anchored hearing implants (BAHIs).Study design: Single-center retrospective cohort study.Setting: Large general teaching hospital.Patients: A total of 231 adult patients were included between August 2005 and October 2020, with a minimum follow-up time of 6 months.Intervention: The test group received a BAHI using the LIT-TP (N = 147). The control group underwent surgery using the LIT-TR (N = 84).Main outcome measures: Soft tissue reactions, skin thickening, postoperative complications (e.g., wound dehiscence), and implant loss were compared between the test and control group. Furthermore, Cochlear Bone Anchored Solutions AB (Mölnlycke, Sweden) and Oticon Medical AB (Askim, Sweden) implants/ abutments within the LIT-TP cohort were compared. Validated questionnaires were used to quantify patients' health-related quality of life (HRQoL).Results: Significantly more cases with wound dehiscence and adverse soft tissue reactions (Holgers ≥2) were observed in the LIT-TR cohort (p &lt; 0.001). However, the LIT-TP cohort showed significantly more cases with skin thickening (requiring treatment) within the first 2 years after implantation. There were no differences in implant loss rates, overall soft tissue reactions (Holgers &gt;1), and overall HRQoL between the two patient groups. Significant improvement in the patients' HRQoL after implementation of a BAHI was found in both techniques. The Ponto Wide implant/abutment showed less frequent skin thickening (requiring treatment) and fewer soft tissue reactions compared with the BIA400 implant/ abutment.Conclusion: This large-scale study demonstrates that the LIT-TP shows excellent long-term outcomes, including a low incidence of implant failure.</p