APPROACH TO DORSAL PONTINE LESIONS VIA THE 4TH VENTRICLE WITH SSEP MONITORING - A REPORT OF 2 CASES

Operative morbidity is a limiting factor for the trans-fourth ventricu lar approach to brain stem lesions. The usefulness of somatosensory ev oked potentials (SSEP) in this approach has not been established, Two patients with pontine lesions were operated on with SSEP monitoring us ing the trans-fourth ventricular approach, One patient had a cavernous haemangioma and the other had a chordoma invading the pens. SSEP rema ined normal in the first, and a slight transitory decrease of the ampl itude was observed in the second patient, The lesions were macroscopic ally totally removed with minimal postoperative neurological deteriora tion. In this approach it is assumed that SSEP monitoring was especial ly helpful for removal of the lesions extending deeply in the pens. (C ) Pearson Professional 1996