I never heard of it, either, but it would be reasonable if the pain is so excruciating and it lasted for a very long time (at least 6 months). Tennis elbow is basically a field that 90% or so could be dealed with medication and rehabilitation. But sometimes a severely calcified tendon or profound fibrosis that affects the limb function or quality of life may require surgical repair. The point is that a thorough exam should be done first, including ultrasound or MRI, to investigate the cause and ensure the necessity of operation. Besides, the patient's will should be taken into consideration. After all, a surgery can bring about another damage and create potential ailment in the future. Few could bear a new pain after the old one is totally/partially relieved. So discussion with the doctor about reason of failure by conservative treatment, the success rate of surgery and the possible complications is mandatory.
My personal opinion is, if the pain is still tolerable and the worry about the risk of surgery is impossible to get rid of, then prolonged rehabilitation and proper ergonomic adjustment may ease the pain eventually, even though it takes (a long) time.