Cochlear implantation (CI) has become a routine surgery for rehabilitation of patients with significant sensorineural hearing loss. The procedure traditionally involves a mastoidectomy, followed by a facial recess approach to access the round window. While the transmastoid facial recess approach for electrode insertion has become standardized practice, the optimal placement for the internal receiver-stimulator (R/S) is still the subject of debate 1-3. One traditional method of fixation for the R/S involves drilling of a bony bed in the calvarium with or without the use of additional securing methods (i.e., tie-down sutures). However, over time, particularly with thinner R/S devices, practices have gravitated towards minimally invasive techniques. In particular, two less invasive R/S placements that have emerged are the tight subperiosteal pocket (more standard), where the implant is positioned above the bone surface but beneath the periosteum, and the tight subgaleal pocket, where the implant is positioned in the plane of loose areolar tissue beneath the galea aponeurotica 4, 5. As opposed to the subperiosteal approach, the subgaleal approach may be indicated in patients with thicker scalps or hair. Because the R/S is placed within a more superficial plane closer to the external receiver, there may be alleviation of magnet retention issues that are a common source of frustration for CI patients, particularly with the newer generation of MRI conditional implants 6. This may avoid the potential for skin flap thinning, which may lead to more wound complications 7. However, it is first important to assess the safety of the subgaleal approach, as the placement of the R/S has numerous potential implications for CI outcomes. For example, if the R/S is not appropriately secured, excessive internal migration of the R/S can result in wound complications or device failure, necessitating revision surgery 2. To the best of our knowledge, there has been no literature assessing the outcomes associated with a subgaleal approach for CI. As such, this retrospective study aims to describe the technical nuances for subgaleal placement of CI devices and assess our institution's outcomes associated with this approach. A retrospective chart review was conducted following Institutional Review Board approval (IRB23-1942). Our inclusion criteria consisted of all adult patients (18 years or greater) who underwent CI surgery by two fellowship-trained neurotologists between January 2014 and February 2025. Specific variables analyzed included demographic variables (e.g., patient age at time of surgery and sex), intraoperative details (e.g., surgical approach, procedure length, estimated postoperative bleeding), and relevant post-operative complications such as magnet retention. Of note, the subgaleal pocket approach was considered as an option starting in fall of 2019, and the rough candidacy criteria utilized for applying this technique was a scalp thickness at the implant pocket site (as measured radiologically or intraoperatively with a puncture needle) as 10 mm or greater. Additionally, patients undergoing subperiosteal pockets do not routinely undergo skin flap thinning at our institution. Categorical data were summarized as percentages and counts while continuous data were presented as medians with interquartile range. To compare the proportions of categorical variables, Chi-square tests were used. Normality was assessed through the Shapiro–Wilk normality test. Non-parametric continuous data were compared through Mann–Whitney U tests, and normally distributed continuous data were compared using Student's T-tests. For all tests, a significance level of p < 0.05 was used. Of the 304 adult patients (median age: 66 years; 53.9% female) who underwent CI between January 2014 and February 2025, 261 patients received a subperiosteal implant while 43 received a subgaleal implant (Table 1). Median follow-up time for patients in the subgaleal cohort was 13 months (IQR 8–31 months). The majority of patients received implants from Cochlear (48.8%) or Advanced Bionics (41.8%), with a smaller number of patients receiving implants from MED-EL (10.5%) (Table 1). Demographic factors such as male sex and high body mass index were significantly associated with the utilization of a subgaleal approach as opposed to a subperiosteal approach (p < 0.001, p < 0.001). Regarding intraoperative outcomes, there was no association between surgical approach and bleeding (p = 0.52) or procedure length (p = 0.25) (Table 2). Postoperative complications were rare, with no patients developing hematoma or wound infection and three patients developing wound breakdown. All three patients who experienced wound breakdown responded to conservative treatment. Because of the small number of patients experiencing these complications, these sequelae were excluded from statistical analysis. Issues with magnet retention were more common, with 44 patients (14.5%) reporting issues in the 2 weeks postoperative follow-up or subsequent routine appointments with their audiologist (Table 1). However, there was no association between surgical approach and issues with magnet retention (p = 0.74) (Table 2). The CI surgery proceeds in standard fashion with a lazy-S type post-auricular incision, elevation of the mastoid periosteum, and cortical mastoidectomy with posterior tympanotomy through the facial recess. Subgaleal dissection starts in the loose connective tissue present lateral to the temporalis muscle and medial to the galea (Video 1). As the subgaleal pocket is developed posteriorly, the temporalis insertion site is traversed and the medial surface of the pocket becomes only periosteum. A radial incision is then fashioned down to the bone through the posterior aspect of the temporalis muscle, fascia, and periosteum, starting at a point estimated to coincide with the expected position of the anterior aspect of the receiver-stimulator. The resulting tissue edges are elevated in a subperiosteal plane. Upon completion of all required drilling, the receiver-stimulator device is delivered into the subgaleal pocket. Absorbable sutures are used to close the temporalis fascia over the proximal hub of the electrode array to fix the receiver-stimulator device in place. Absorbable sutures are preferred for this step to prevent any risk of microtrauma to the array over the long term at the interface between suture and device. The remainder of the procedure including electrode insertion then takes place in standard fashion. The incision is closed in a multi-layer fashion, and a mastoid pressure dressing is placed over the ear for 24–48 h. We describe our institution's experience with a novel subgaleal approach for R/S placement in CI. Within our cohort of 43 patients selected for the subgaleal approach, we observe no increase in intraoperative bleeding or operative time compared to patients selected for the subperiosteal approach. Importantly, no early postoperative complications such as hematoma, wound infection, or magnet retention issues were observed within the subgaleal cohort during the median follow-up time of 13 months. Most CI manufacturers advise that for proper retention of an external receiver, the skin flap above the R/S should be no more than 7 mm 8. Given the significant association between increased BMI and increased skin flap thickness as well as growing obesity trends, magnet retention may be a growing concern amongst CI patients 6, 9. A subgaleal approach decreases the distance between the R/S and external receiver, theoretically increasing the strength of the magnetic attraction and preventing potential magnet retention issues. In our study, most patients received a subgaleal approach because they were identified upfront to have thicker scalps (roughly 10 mm or greater) or bulky hair, thus potentially being at higher risk for magnet retention issues. Despite these risk factors, we observed that magnet retention issues occurred in only 11.6% of subgaleal patients, a rate comparable to the 14.9% observed within the subperiosteal cohort. While direct comparison of subgaleal and subperiosteal groups is limited by selection bias, these findings suggest that a subgaleal approach might mitigate increased risk of magnet retention problems in appropriately identified patients. It is important, however, to consider possible complications that may arise from a subgaleal approach. Because the R/S is secured in the plane of loose areolar tissue and not directly against a rigid bony surface, there may be a theoretical increased risk of device migration. If the displacement is severe, there can be complications such as device failure, pain, hematoma, or poor audiological outcomes due to displacement of electrodes from the cochlea 1, 10. This may then necessitate revision surgery. In our technique, we address this concern by using absorbable sutures to close the temporalis fascia over the proximal hub of the electrode array. No major complications were reported within the cohort of patients who received a subgaleal approach. However, longer follow up is needed in order to fully assess the stability of R/S fixation in this approach, as issues like device migration may manifest years after initial implantation. Another limitation of this study is its nonrandomized design. Patients undergoing the subgaleal approach were predominantly male and obese, reflecting our selection criteria. This methodology precludes direct comparisons of complication rates between the subgaleal and subperiosteal cohort and limits causal conclusions about relative safety. Lastly, the small subgaleal cohort limits power in detecting differential outcomes regarding rare postoperative complications in addition to limiting our ability to perform a multivariate analysis. Despite these limitations, our institution's early experience with the subgaleal approach suggests that this may be an alternative technique for patients that do not add intraoperative complexity or increase early postoperative complications. In the future, longer term studies with larger cohorts are necessary to more fully evaluate the long term safety of the subgaleal approach. The subgaleal approach is an alternative for R/S placement during CI surgery that does not increase intraoperative bleeding, operative time, or early postoperative complications. The authors have nothing to report. The authors have nothing to report. The authors declare no conflicts of interest. The data that support the findings of this study are available from the corresponding author upon reasonable request.
Rama et al. (2026) studied this question.