[Long-term outcome after reconstruction of the cranial base with ionomer cement]

Congenital, posttraumatic, inflammatory or tumours skull base lesions with CSF leakage require reconstruction to mechanically stabilize the CNS and to securely seal the CSF space.

Ionomeric cement was used from 1988 until 1994 in 44 patients for skull base reconstruction at the Department of Otolaryngology-Head and Neck Surgery, University of Würzburg. Thirty-five patients were reexamined. The longest follow-up time was 8 years. The program for the present follow-up study comprised a general ENT and neurological examination as well as CT scans of the skull base, MRI tomography of the CNS, and the determination of the aluminium plasma concentration.

None of the patients reexamined presented with complaints. Neurological examinations and MRI tomography in all patients did not reveal any pathological finding related to ionomeric cement application. Aluminium plasma concentrations in patients who received ionomeric cement implantations were not significantly elevated when compared to controls. General ENT examinations and CT scans in thirty-two patients demonstrated regular postoperative findings. The cement at the anterior skull base was not covered completely by mucosa in three patients. In one these cases, CT scans revealed dislocation of the ionomeric cement so that revision surgery was performed for removal. None of the patients to date presented with a CSF leak.

Long-term results of the present study show that ionomeric cement is a suitable material for closure of osseous skull base lesions to permanently seal the CSF space. These results, however, can only be obtained when handling and application of the material is adequate. Unfortunately, the production of ionomeric cement has been stopped since 1995 following four cases of aluminium encephalopathy reported in the literature.