The Short- and Long-Term Safety of S53P4 Bioactive Glass for Mastoid Obliteration: a Retrospective Comparative Study

In recent years, mastoid obliteration (MO) after mastoidectomy has gained popularity. However, the choice for obliteration material has been a point of discussion. Autologous materials have the advantage of being freely available without cost.Synthetic materials on the other hand have unlimited supply, hold volume over time and have no risk of donor site morbidity. Comparative studies between materials are rare and the few available were unable to ascertain superiority.

Our hospital has been utilizing the same material for obliteration since 2011: S53P4 bioactive glass (BAG). It since has become our main operating procedure to obliterate the mastoid cavity with BAG granules following both canal wall up (CWU) and canal wall down (CWD) mastoidectomy. This bioactive glass has several important characteristics, such as the retaining of volume over time and antibacterial properties.

An important factor when selecting obliteration material is safety. Data on this was reported in several studies, but unfortunately these studies only investigated short-term safety in small and selected cohorts of patients, often without comparison. Additionally, large studies with extensive follow-up are necessary to detect rare complications and long-term pitfalls. Therefore, the aim of this study is to determine the safety of BAG in a cohort that encompasses all cases that underwent CWU+MO and CWD+MO in our institute and compare these results to a non-obliteration cohort. The main outcomes are short- and long-term safety, as indicated by surgical complications in the first year following surgery and revision surgeries during follow-up, respectively. The investigators will compare the obliteration cohort to the non-obliteration cohort, hypothesizing that obliteration results in a comparable or lower rate of complications and revision surgeries