My son (adult) had surgery for an inguinal hernia 7 years ago and another surgery to the same site 3yr ago for increased pain. The Dr. removed the old mesh and used new mesh. He has never been pain free and the pain continues to increase. The first surgeon referred to another surgeon who says it is nerve pain and referred to Pain Management. The PM doctor is recommending Ketamine infusions, 1/day x5 days. Has this drug been found successful for this type of nerve pain?