High precision cochleostomy by use of a pulsed CO2 laser - an experimental approach.

A precise cochleostomy is a crucial step in cochlear implantation, particularly if residual hearing is to be preserved. A contactless ablation of the promontory bone by a pulsed CO(2) laser system seems to be a promising approach. The bone is removed by a scan head controlled laser beam in sequential scan cycles with a pulse rate of 50-100 mus. Digital picture analysis and pattern detection are used to identify the membranous lining of the cochlea. We achieved a bone ablation in a micrometer range per scan cycle with the laser. A perforation of the promontory bone could be detected by automatic pattern detection. The enhancement of automatic pattern detection can lead to a minimally invasive, function-preserving laser cochleostomy.

Pneumocele as a rare differential diagnosis in trigeminal irritation.

A case of a pneumocele concerning the maxillary sinus causing trigeminal irritation is presented. Pneumoceles are rare conditions of an abnormal dilatation of a paranasal sinus containing only air, lined by unremarkable mucosa, and associated with a bony defect. Symptoms, diagnostic findings, therapy, possible causes, and pathogenesis are discussed.