Labyrinthotomy with streptomycin infusion: early results of a multicenter study. The LSI Multicenter Study Group.

Early results for hearing and vertigo are reported for 47 labyrinthotomies with streptomycin infusion (LSI) by 13 coinvestigator-surgeons. Sixty-eight percent of patients had worse hearing after surgery (10 dB or 15% word recognition). Patients with a preoperative pure-tone average better than or equal to 40 dB appeared to suffer less postoperative hearing loss than those with a greater preoperative deficit. Severe to profound postoperative hearing loss was experienced by 27 patients (57%), all of whom had preoperative pure-tone averages worse than 40 dB. Opening the endolymphatic space was associated with a deleterious effect on hearing. Because of persistent vertigo, 17 percent of patients required a secondary procedure during the period of observation. These early results indicate that LSI is associated with a significant risk of postoperative hearing loss. Of the 13 coinvestigator-surgeons, four have stopped using LSI, while one considers his results satisfactory. The remaining surgeons have taken an intermediate position and feel it is useful in selected cases. Longer follow-up is required to judge the efficacy of LSI for controlling vertigo. We are currently studying these long-term results.