Safety and Effectiveness of Bone Allografts for Mastoid Obliteration After Mastoidectomy: A Pilot Study.

Background and objectives: Various materials are used to perform post-mastoidectomy mastoid obliteration (MO) to reduce the risk of recurrent infections, stasis of secretions, or caloric dizziness. Autologous materials used as fillers for MO tend to be insufficient owing to shrinkage over time or inadequate volume of these substances. Synthetic materials are unsatisfactory for MO because of the risk of rejection and extrusion. We investigated the safety and effectiveness of bone allografts for post-mastoidectomy MO.

Subjects and methods: We reviewed the medical records of patients who underwent mastoidectomy with MO between January 2013 and January 2021. In the MO group, bone allografts were additionally used to fill the residual mastoid cavity. In the canal wall down (CWD) group, all patients underwent CWD mastoidectomy with use of additional inferiorly based mucoperiosteal flaps.

Results: The study included the MO group (23 ears) and the CWD group (53 ears). In the MO group, compared with the preoperative status, we observed a decrease in the tendency of the air-bone gap postoperatively. Compared with the CWD group, the total complication rate showed a decreasing tendency in the MO group.

Conclusions: No patient showed post-MO shrinkage of the grafted bone allograft or otorrhea. Further large-scale studies are warranted to confirm the advantages of bone allografts for MO, including maintenance with time and sufficient amount.