hernia---- a painful experience

I operated on 18 year old male for rt ing hernia.The operation was uneventful to say the least. Pt complained of severe pain in the rt thigh radiating upto knee jt. on the 8th post op day. O/E there was mild seroma in the wound and nothing else. Antibiotic and analgesic are of no use. ON 17th day I consulted my senior who discovered some paralytic neurologic disorder on both lower limb and draw the inference of some preexisting neurological disease Treatment started accordingly.