We present our experience in the management of otalgia in posterior chemosurgery tympanotomy in children with optic topical Ketamine for a year (January 1st to December 31th of 2011) In the San Jose-Tex Hospital of Monterrey and in the Christus Muguerza High Specialty Hospital of Monterrey, NL, Mexico. Control of pain in the recovery area, valued by subjective scale, analogous visual, numerical scale, etc., much better results in patients who received topical ketamine 1 mg x kg Optics dividing in two ears. As well as the anticipated started of oral diet, better mood, no crying, vomiting absence. The anticipated merger to their usual activities, sports, etc. he did not need outside the hospital analgesic was also observed in these patients. If signs the role of nociceptors that are the peripherals of the pain receptors through neurotransmissions send their messages to the middle lane. We reference the difference between the two types of nerve fibers. The fibers (delta) are myelinated fibers with a diameter of 1-5 microns, with fast conduction velocity (4 to 30 meters per second), led signs / markings pain of short latency that need quick answers. C fibers, are unmyelinated fibers with a diameter of 0.3 to 1.5 microns, with slow conduction velocity (0.4 to 2 meters per second), this is the largest group, transmit the nociceptivos, thermal, mechanical and report on sensations of BURNING pain and of more EXTENSIVE latency, are polymodal nociceptors, that is, respond to multiple stimuli (thermal, mechanical, chemical). Special mention pain transmission and neuro modulation where the biochemical changes that have.