Transmastoid Repair of Minor Skull Base Defects with Flexible Hydroxyapatite Sheets

This prospective open pilot study was designed to assess the suitability of flexible composite sheets of polymer and hydroxyapatite (HA) for the reconstruction of limited lateral skull base defects through a conservative transmastoid approach.Seven patients with a petrous bone dehiscence less than 3 cm in diameter, either iatrogenic or caused by chronic otitis media or temporal bone trauma, underwent a mastoidectomy. The defect was repaired with the new material and a connective tissue graft. All bone defects were detected by computed tomography (CT) of the temporal bone except one that was found at surgery in an asymptomatic patient.Outcome was evaluated in terms of anatomical integrity of the tegmina, absence of cerebrospinal fluid leaks, side effects, and extrusion and complication rates. None of the patients suffered from immediate side effects related to the implant or the operation. With a minimum follow-up of 18 months (maximum, 62 months), neither extrusion nor a foreign body reaction occurred. Postoperative CT confirmed a satisfactory anatomic contour. Although the number of patients is limited, these preliminary results are encouraging and indicate a need for further clinical trials with a material that allows a minimally invasive approach to selected skull base defects.