Luotonen J, Laitakari K, Karjalainen H, Jokinen K
Department of Otolaryngology, University of Oulu, Finland.
Acta Otolaryngol Suppl. 1992;492:63-7. doi: 10.3109/00016489209136812.
An ideal agent for local anaesthesia of the tympanic membrane has been missing so far. Recently, however, a eutectic mixture of lignocaine and prilocaine (EMLA, Astra, Södertälje, Sweden) has proved promising. We compared the anaesthetizing efficacy of EMLA, Bonain's solution (cocain, menthol, phenol ana partes) and Xylocain-spray (Astra, Södertälje, Sweden) in 42 voluntary subjects. EMLA was applied on one tympanic membrane and either one of the other two agents in the other ear of each subject. Small cotton pledgets were used for application. Sensitivity of the ear drum was tested under otomicroscope with a cotton tipped wire before and after each local anaesthesia. Full anaesthesia could be reached with EMLA very significantly (p less than 0.001) more often than with Xylocain and almost significantly (p = 0.057) more often than with Bonain's solution. Most of the test subjects preferred EMLA to Bonain's solution of Xylocain. Undesired side effects, including two tympanic membrane perforations, appeared in most of the ears anaesthetized with Bonain's solution. In the clinical part of the study, EMLA topical anaesthesia was used in 127 minor policlinical tympanic membrane procedures like myringotomy and tympanostomy tube assembling. Eighty-three of the procedures were assessed as painless, 36 unpleasant and 8 painful. A 30-min action time of EMLA was considered sufficient in most cases. No EMLA related side effects appeared. In conclusion, Bonain's solution is recommended to be replaced by EMLA or a corresponding agent for local anaesthesia of the tympanic membrane.
