## 3 Results  
The number of events and long-term device survival are reported here. There were 272 complete datasets. A further 20 datasets had extensive missing data, excluding them from analysis. These unused datasets occurred in cases where follow-up data was not recorded due to patients not attending appointments or changing clinics. There were 109 BB cases (73 retrospective and 36 prospective) and 163 VSB cases (132 retrospective and 31 prospective). For the BB cases, one patient was implanted bilaterally; there were 39 SSD cases implanted unilaterally; and the rest were unilateral implants in people with bilateral mixed or conductive hearing losses. The average age at implant was 46 years (10-74 years; 2 under 18 years), and there were 63 females and 46 males. For the BB the mean four-frequency average (4 FA; 0.5, 1, 2, 4 kHz) air conduction thresholds for those with sensori-neural or mixed losses and SSD was 106 dBHL in the deaf ear and for mixed or conductive bilateral deafness was 64 dBHL (mean air-bone gap of 44 dBHL). For the VSB cases, 21 patients were implanted bilaterally; there were 71 with sensori-neural, 78 with mixed, 13 with conductive losses, and in 1 case, the information on type of hearing loss was missing. The average age at implant was 55 years (5-84 years; 3 under 18 years), and there were 91 females and 72 males. For the VSB, the mean four-frequency average (4 FA; 0.5, 1, 2, 4 kHz) for those with sensori-neural losses was 79 dBHL, and for mixed or conductive losses, it was 84 dBHL (mean air-bone gap of 31 dBHL). For the BB, there were a total of 18 events (16.5%), of which 6 (5.5%) were SAEs. Two SAEs required reimplantation or transplantation, two required flap thinning surgery to improve the stability of the external components, and two needed intravenous antibiotics. The mean follow-up period per BB device was 4.0 years. For the VSB there were 42 (26%) events in total of which 19 (11.5%) were SAEs. Fifteen required reimplantation or transplantation; three required re-positioning of the transducer; and one needed intravenous antibiotics. The mean follow-up period per VSB device was 6.0 years. Figure 1 shows the distribution of events for the different devices. For both devices, magnet events were recorded when causing pain or pain with an adverse skin response. There were 7 cases for the BB and 2 for the VSB. The details of the breakdown of event categories together with the etiology for the BB and VSB are shown in Tables 1 and 2, respectively. \begin{table}
\begin{tabular}{c c c c} \hline
**Event Specifics** & **Number of Cases** & **Comment** & **Etiology** \\ \hline Minor pain & 2 & Flap thickness issue, unresolved & Unknown, labyrinthitis \\ Pain & 6 & Magnet too strong, resolved by & CSOM, otitis externa, ototoxicity \\  & & changing strength & (gentamicin), Unknown (SSD) \\ Facial nerve insult & 1 & All spontaneously recovered & Otsclerosis \\ Wound infection & 1 & Antibiotics & Stenosis \\ haemorrhage & 2 & Resolved intraoperatively & CSOM, Unknown \\ Wound infection & 2 & Intravenous antibiotics & Otitis Externa, Unknown \\ Major pain & 2 & Flap thinned in surgery & 2 \(\times\) CSOM \\ Major pain & 1 & Explanation & Unknown \\ Device failure & 1 & Reimplantation & Stenosis \\ \hline \end{tabular}
\end{table} 
Table 1: Device-related events for BB. CSOM = Chronic suppurative otitis media; SSD = Single-sided deafness.