FATAL ENCEPHALOPATHY AFTER OTONEUROSURGERY PROCEDURE WITH AN ALUMINUM-CONTAINING BIOMATERIAL

Refractory status epilepticus was observed in two patients who underwe nt vestibular neurectomy. We investigated the relationship with the us e of an aluminum containing bone cement during the procedure. Two pati ents developed focal and thereafter generalized seizures in the late p ostoperative period of vestibular neurectomy (respectively after 42 an d 35 days). A cement (1 g aluminum-calcium fluorosilicate) was used du ring the procedure to bridge bone defects. Both patients presented cer ebrospinal fluid fistula. Investigations excluded common etiologies, i n particular infections, and a toxic oligin was suspected. Aluminum co ncentration was determined repeatedly in serum urine, cerebrospinal fl uid and retroauricular fistula. The highest aluminum values were respe ctively in case 1 and 2, 112 and 63 mu g/L for the cerebrospinal fluid , 495 and 1440 mu g/L for the fistula, 4.4 and 4.4 mu g/L in Serum. De sferrioxamine was used as chelating agent and aluminum elimination was analyzed in the urine. Status epilepticus became refractory to intens ive care therapy. The patients never recovered normal consciousness. C ase 1 died 143 days after the procedure and case 2 at 80 days from bra in failure. Brain post-mortem examination was obtained in Case 2. Bria n aluminum concentration was 2.5 mu g/g (wet weight) (0.85 mu g/g in a control non exposed cadaver). The cement (0.2 g) was incubated in vit ro (16 h-37 degrees C) with the cerebrospinal fluid of a control patie nt (cerebrospinal fluid aluminum 8 mu g/L): aluminum concentration rea ched 2750 mu g/L. A close contact between an aluminum containing cemen t and the cerebrospinal fluid may have resulted in encephalopathy and fatal status epilepticus in these two patients.