Cryoablation
Interview with Dr. J. David Prologo, Director of
Interventional Radiology Services at Emory Johns Creek
Hospital and Assistant Proferssor at Emory University
June 2018
Violet: Please describe the cryoablation procedure for a patient with chronic pelvic pain due to pudendal neuralgia (PN).
Dr. Prologo: The cryoablation procedure has evolved over the last 4 years for the management of patients with pain secondary to pudendal neuralgia. The procedure itself is a 2 step process during which CT guidance is used to, 1) inject the pudendal nerve for diagnostic reasons, and 2) cryoablate (freeze) the pudendal nerve in patients who respond positively to the injection.
Violet: How did you become interested in using cryoablation for PN patients?
Dr. Prologo: We started using cryoablation to treat patients with cancer pain. We began freezing nerves to block pain in patients with large tumors. From there, we began applying the technique for multiple other scenarios. It was actually a very smart patient who brought pudendal neuralgia to my attention.
Violet: How do you determine if a patient with PN is a good candidate for cryoablation?
Dr. Prologo: This is a very important question. For now, the response to the injection is the most important predictor. There are many stories and many causes of pelvic pain. The injection helps us sort it out. Secondly, the distribution of pain is very important – perineal and vaginal pain patients do the best.
Violet: How is cryoablation different from pulsed radio frequency ablation and why would you recommend it instead for PN?
Dr. Prologo: Cryoablation causes a predictable degeneration and regeneration of the nerve, a process that takes 8-12 months. Pulsed radiofrequency “scrambles” the nerve signalling machinery – which lasts for several months (at least) as well. I do not recommend one over the other, necessarily – what is important is the image guidance. CT allows us to precisely place these ablation probes for treatment.
Violet: Where along the nerve do you apply the treatment? Can you treat the smaller branches such as the dorsal nerve branch or do you just treat the main trunk of the pudendal nerve?
Dr. Prologo: In the beginning we only treated distally – far into the canal. After some time and a better understanding of cryoablation and nerves, we have moved proximally (closer to the entrance into the canal). We cannot target the branches specifically in CT.
Violet: Does it make a difference whether the patient has pain due to peripheral pudendal neuropathy vs. spinal radiculopathy as to whether the treatment is likely to be successful? Do you know of a good way to tell which a patient has – spinal radiculopathy vs. peripheral neuropathy?
Dr. Prologo: Yes it definitely makes a difference. This is why we do the injection, actually. Temporarily shutting down the pudendal nerve using CT guidance will not affect centrally originating symptoms. Great question.
Violet: What expectations should a patient have as far as total vs. partial pain relief? Does the procedure usually need to be repeated?
Dr. Prologo: This really depends on the patient and the cause of the neuralgia. Straightforward patients with classic stories (bike rider, pelvic surgery) and a positive response to the block do best. We usually do not repeat the procedure.
Violet: What are the risks and complications associated with cryoabaltion? What happens to the nerve and is there a risk of incontinence or loss of sensation and motor function? Can it make the pain worse?
Dr. Prologo: This is another very important question. We are compiling data from 3 separate institutions using a follow up survey to get an accurate answer to this question.
Preliminarily, our early results are suggesting that approximately 95% of patients who undergo the procedure do so without significant new or worsening incontinence. Importantly for those that have experienced such symptoms, nerves that undergo cryoablation ultimately regenerate – such that any loss of sensation or function is temporary. Our hope is that the regeneration occurs without recurrence of pain.
Violet: Are there activity restrictions for patients who have undergone cryoablation?
Dr. Prologo: No.
Violet: Does insurance typically cover the procedure?
Dr. Prologo: This is case by case. The American Medical Association has assigned a CPT code to this procedure, but reimbursement mechanisms are evolving. At this point our institution does not bill insurance.
Violet: Have you successfully treated any patients with persistent genital arousal disorder (PGAD) using cryoablation, and is it something you would recommend a patient with PGAD try?
Dr. Prologo: I have not. This makes sense but I believe we will need a study to evaluate.
Violet: Do you know of any other doctors using cryoablation to treat PN patients and what the typical success rates are?
Dr. Prologo: Yes. We are in contact and collaborating to compile all of our data and results, including survey follow up, to answer this question. We hope to have this finished by the end of the year.
Violet: Please add any additional comments you feel are important.
Dr. Prologo: What has clearly emerged during recent years is that pelvic pain is often complex with many causes. For those conditions in the body where a nerve is clearly responsible for the pain, cryoablation can result in significant relief. On the other end of the spectrum are cases that are not clearly pudendal neuralgia, are partly neuralgia, or are unrelated to the pudendal nerve. We are working very hard to isolate variables which will predict success.
So, the take home point is that this procedure can lead to significant relief – for the right patients. Selecting those patients up front will be critical as we move forward with continued hopes and efforts to help human beings. Thank you so much!
Violet: Thank you for answering these questions! Thank you for your care and concern for patients.