DISCUSSION
Bioresorbable and biodegradable osteosynthetic fixation plate PDLLA systems offers several advantages over the traditional osteosynthesis with non-biodegradable materials (such as titanium meshes, Gore-tex implants, malleable ceramics, and acrylates), including the absence of corrosion and metal accumulation in tissues and of removing the implants after osseous healing; the ease of molding it to the requested shape by hand after softening in hot water for a few minutes; the chance to further trim it by a drill with a soft diamond bur when hardened (quickly, after 10-15 minutes); the absence of inflammatory or foreign body reactions or granuloma formation, owing to its optimal bio-compatibility. Histological studies demonstrated that PDLLA determines a local fibrous tissue growth that tightens the bond to bone and to the surrounding tissues, including synthetic implants. The bonding strength is guaranteed for 8-10 weeks.2, 3Disadvantages are the maximum load tolerance, which is lower than metallic meshes, and allergic reaction in sensitive subjects (a skin patch test is recommended in allergic patients).
Magnet extrusion or migration is more likely after CI revision surgeries owing to skin-muscle flap devascularization or atrophy related to repeated coagulation, scarring, infection, or foreign body reactions.4 Therefore, a resorbable material, stiff enough to prevent the magnet extrusion in the short term, and that could be stable enough in the long term, possibly being replaced by a thick fibrous layer avoiding exposure and/or ulceration was needed. Since there were no reports in the literature, we were concerned about possible tissue reaction to PDLLA: a fibrous encapsulation of the PDDLA mesh might have been causing an excessive thickening of the soft tissues over the R/S, impeding a correct coupling of the external speech processor and, on the other hand, a rapid biodegradation might have provoked a new magnet dislocation soon after revision surgery.