Extracorporeal Shockwave Therapy: Hope Or Hype?

Author(s): 
By Lowell Scott Weil, Jr., DPM, MBA; By Patrick A. DeHeer, DPM, with Stephen M. Offutt, DPM, Gary A. Trent, DPM, and Michael J. Baker, DPM

Hope. Lowell Scott Weil Jr., DPM, says ESWT is a non-invasive alternative with minimal risk for patients who have failed conservative treatment for plantar fasciitis. Medical devices and technology are constantly changing and evolving with the “newest and best” treatments being constantly promoted. Whenever new treatments emerge, they must be looked at carefully and critically to assess their efficacy and safety. They must also be compared to the currently accepted treatments and their benefits over those modalities. Extracorporeal shockwave therapy (ESWT) for the treatment of musculoskeletal (MSK) disorders evolved in Europe in the early 1990s. ESWT is a derivative of lithotripsy, the mechanical breaking up of renal stones with sound waves. ESWT has been considered valuable in treating many different MSK disorders including plantar fasciitis, epicondylitis, tendinitis and non-unions of bone. In all situations, it is considered the non-invasive alternative to surgery. Regardless of the pathology that ESWT is used for, one should only consider it after more common, accepted and proven noninvasive treatments have failed. Plantar fasciitis is the first pathology that was FDA approved for ESWT treatment in the United States. Up to 15 percent of podiatric visits result from painful plantar fasciitis. Given the prevalence of plantar fasciitis in the U.S. (with over 1 million people suffering from it annually), it has become the epicenter of debate about ESWT. However, numerous studies have proven that 80 to 90 percent of people suffering with plantar fasciitis will be successfully treated conservatively over a six-month period of time. There is little debate over the most effective conservative management options for plantar fasciitis, with the only randomized proven method being night splints in the chronic cases. Yet controversy is never far from a discussion about the proper method of treating the 10 to 20 percent of plantar fasciitis sufferers who do not respond to conservative care in a timely fashion. Pointing Out The Potential Shortcomings Of Surgical Options Over the years, many different procedures have been described for treatment of chronic heel pain. They have included: large incisional sectioning of the plantar fascia with removal of bone spur to only sectioning the plantar fascia; decompression of a branch of the lateral calcaneal nerve with partial sectioning of the plantar fascia; minimally invasive techniques with or without an endoscope; in-step fasciotomies; and, more recently, injections of different chemical agents (either Botox or alcohol). In the past three years, ESWT has been added to the list of available treatments in the U.S.. Why have surgeons continued to change their procedure of choice over the years despite citing literature with good to excellent early results? It is probably the same reason why there are over 100 bunion operations. They are searching for the procedure that is predictable over the long term with the least amount of complications and headaches for both the patient and surgeon. We have certainly heard surgeons proclaim minimally invasive surgery as being approximately 95 percent successful with no complications and immediate full weightbearing. Certainly, those statistics are far from reality. Any time one performs invasive surgery, there are risks involved. It is not uncommon to hear of the patient who had an endoscopic plantar fasciotomy (EPF) performed that resulted in severe nerve injury to branches of the plantar nerve. We also encounter the patient who has had open sectioning of the plantar fascia and removal of the bone spur only to be in severe pain for months with an inability to return to work or pursue normal activities over that timeframe. While these scenarios may be unusual, they are certainly more common than we would like. A Closer Look At The Literature On ESWT ESWT has emerged as a noninvasive, minimally risky procedure for chronic conditions such as plantar fasciitis. ESWT allows patients to return to activities of daily life within one or two days with an immediate return to most occupations and normal daily shoegear. While complications have been described, they are more corporate disclaimers than actual pathologic entities. Opponents of ESWT point to literature that shows its ineffectiveness and its high cost. Without doubt, the literature is clouded as to the relative benefit of ESWT. There is literature on both sides of the debate. One can selectively quote literature to support a stance on ESWT either way. Some of the more discussed papers against ESWT have been scientifically flawed. The paper most often cited by the opponents of ESWT is by Buchbinder out of Australia. This study included patients who had heel pain for as little as six weeks and the authors used ESWT energy levels that were far less than those recommended in the U.S. Additionally, the authors of the study administered a small but nevertheless present dose of ESWT to the placebo group. Lastly, the study was performed by a non-clinician who worked for the government of a national health care system. The motives of the study were skewed from the beginning. We published a paper in the Journal of Foot And Ankle Surgery (JFAS) that showed an 82 percent success rate with ESWT, which was comparable to our study of minimally invasive plantar fasciotomy (83 percent success) in JFAS. Critics of our ESWT paper will correctly point out that it is a retrospective study and that only a randomized, prospective, placebo-controlled study can accurately show the true value of a procedure. This is true. However, all of the studies on surgical outcomes for plantar fasciitis are similarly designed as retrospective without the control of a placebo group. Therefore, our study shows that outcomes with ESWT are comparable to surgical outcomes without the risks and complications inherent to surgery. Assessing The Cost Benefit Of ESWT Critics will also point out that ESWT is extremely expensive. Without doubt, the cost of ESWT is high. However, the cost of new technologies, as with new pharmaceuticals, is often high. The benefits of ESWT in terms of social costs are immeasurable. Patients are able to return to activities of daily life and work immediately. There are no costs of lost work to either the patient or employer. There are no risks such as infection. Postoperative infections require intense medical care that can run into tens of thousands of dollars. These are just some of the examples of the overall cost benefit of ESWT over surgical options. Final Notes ESWT has a long way to go in proving the overwhelming medical benefits that are claimed by the manufacturers, but it is still in the early stages of its evolution. With time, it will be necessary to prove these claims through prospective studies. Additionally, a scientific explanation as to the mechanism of action and physiologic effects of shockwave therapy is necessary to further understand the medical applications. Ultimately, I have to ask you the question: If you had painful plantar fascitis that failed to respond to conservative care over six months, what would you choose? Surgery or ESWT? Dr. Weil is the Fellowship Director of the Weil Foot And Ankle Institute in Des Plaines, Ill., and is a Fellow of the American College of Foot and Ankle Surgeons. References 1. Tomczak RL, Haverstock BD. A Retrospective Comparison of Endoscopic Plantar Fasciotomy to Open Plantar Fasciotomy with Heel Spur Resection for Chronic Plantar Fasciitis/Heel Spur Syndrome. J. Foot Ankle Surg. 34(3): 305-311, 1995. 2. Gill L, Kiebzak G. Outcome of Non-surgical Treatment for Plantar Fasciitis. Foot Ankle Int 1996; 17: 527-532. 3. Weil LS, Gouldwing PB, Nutbrown NJ. Heel Spur Syndrome. A Retrospective Study of 250 Patients Undergoing a Standardized Method of Treatment. J. Foot Ankle Surg. 4: 69-78, 1994. 4. Benton-Weil W, Borelli AH, Weil Jr. LS, Weil Sr. LS. Percutaneous Plantar Fasciiotomy: A Minimally Invasive Procedure for Recalcitrant Plantar Fasciitis. J. Foot Ankle Surg. 37(4): 269-272, 1998. 5. Jerosch JU. Endoscopic Release of Plantar Fasciitis - A Benign Procedure? Foot Ankle, 21: 511-513, 2000. 6. Alvarez R. Preliminary Results on the Safety and Efficacy of the Ossatron for Treatment of Plantar Fasciitis. Foot Ankle Int. 2002; 23: 197-203. 7. Weil Jr. LS, et al.: Extracorporeal Shock Wave Therapy for the Treatment of Chronic Plantar Fasciitis: Indications, Protocol, Intermediate Results, and a Comparison of Results to Fasciotomy. JFAS 41(3), 2002. 8. Chen HS, et al: Shockwave Therapy for Patients with Plantar Fasciitis: A One-Year Follow-Up Study. Clinical Orthopedics and Related Research 387: 41-46, 2001. 9. Wang CJ, et al: Shockwave Therapy for Patients with Plantar Fasciitis: A One-Year Follow-up Study. Foot and Ankle International, 23(3), 2002. 10. Ogden JA, et al: Shockwave Therapy for Chronic Proximal Plantar Fasciitis: A Meta-Analysis. Foot & Ankle International 23(4), 2002. 11. Hammer DS, et al: Extracorporeal Shockwave Therapy (ESWT) in Patients with Chronic Proximal Plantar Fasciitis. Foot & Ankle International 23(4), 2002. 12. Buchbinder R, et al.: Ultrasound-Guided Extracorporeal Shock Wave Therapy for Plantar Fasciitis: A Randomized Controlled Trial. JAMA 288(11), 2002. 13. Rompe JD, et al.: Shock Wave Application for Chronic Plantar Fasciitis in Running Athletes: A Prospective, Randomized, Placebo-Controlled Trial. The American Journal of Sports Medicine 31(2), 2003. 14. Dalay PJ, et al.: Plantar Fasciotomy for Intractable Plantar Fasciitis: Clinical Results and Biomechanical Evaluation. Foot and Ankle, 13(41), 1992. 15. Vohra PK, et al.: Long-term Follow-up of Heel Spur Surgery: A 10-Year Retrospective Study. JAPMA, 89(2), 1999. 16. Lundeen RO, et al.: Endoscopic Plantar Fasciotomy: A Retrospective Analysis of Results in 53 Patients. JFAS, 39(4), 2000. Hype. Patrick A. DeHeer, DPM, Stephen M. Offutt, DPM, Gary A. Trent, DPM, and Michael J. Baker, DPM, cite the limited indications of the modality and the lack of a clear and standard procedural protocol for its use. Extracorporeal shockwave therapy (ESWT) is becoming increasingly popular for the treatment of chronic plantar fasciitis despite much controversy over its efficacy. (See a recent headline from USA Today: “Study treads on ‘shockwave’ heel therapy; controversial report finds no evidence that treatment cuts pain.”) As with any controversial topic, there is a pro and con argument. There are some key points to consider on the con side of the ledger. They are as follows: ESWT and its role in the overall treatment algorithm of heel spur syndrome; the prevalence of a neurological etiology for heel pain; the current literature confusion over efficacy and treatment protocols; and, finally, potential complications (primarily recurrence of heel pain). Please understand that while Healthtronics certified me in ESWT approximately two years ago, I have yet to perform ESWT on a single patient. I have several reasons for avoiding the procedure. First and foremost is the lack of insurance coverage for ESWT in the state in which I practice. This lack of coverage seems to stem from some of the current negative literature. My patients have chosen more invasive procedures based upon insurance coverage. Before starting to make my case against ESWT, I have always been intrigued by the strong opinions generated from the surgical treatment of heel spur syndrome. Do bunion surgeries cause such lines in the sand? I don’t think so. Procedures for heel spur syndrome seem to be inherently controversial and it appears that much of the furor stems from the fact that adequate (the important word here) conservative treatment will successfully treat this condition as much as 90 percent of the time. When the endoscopic plantar fasciotomy (EPF) was first introduced, a major concern was that some might employ the procedure as a first line of treatment. Well, standard of care dictates otherwise and, for the most part, the anticipated abuse never took place. Similar to the EPF procedure, ESWT should be well down the treatment algorithm. As with any other invasive plantar heel surgery, adequate conservative treatment should be rendered for six months prior to treatment with ESWT. Avoiding The Bandwagon Mentality With New Procedures The next point I would like to present is that of the “new” procedure mentality and the need to be first one on the block to perform it. For example, prior to the EPF procedure, I had reasonably good success rates with an in-step plantar fasciotomy. However, with a new technique at my disposal, I performed the EPF for approximately five years. My success rate with EPF was definitely less than my success rate with the in-step procedure, with the primary complication being recurrence of heel pain. I subsequently returned to my tried and true procedure and have been doing it ever since. From this experience, I learned that I don’t need to be the first to jump on the bandwagon of a new procedure and that it is probably best to wait and see if research shows a definitive lean one way or the other. When One Considers The Common Etiology Of Most Chronic Heel Pain Cases Another critical aspect in the decision process for ESWT is accurate diagnosis of the etiology of chronic heel pain. I feel strongly that much of chronic heel pain is, in fact, due to an entrapment of the first branch of the lateral plantar nerve (Baxter’s neuritis), and, according to the literature, ESWT is then contraindicated. In their 1984 article, Baxter and Thigpen attributed 20 percent of all chronic heel pain to entrapment of the first branch of the lateral plantar nerve. After several years of experience with this diagnosis clinically, I think that the percentage is actually higher. Initially, I was skeptical about this diagnosis and the resulting treatment, but I started to check for it regularly on my heel pain exam and documented its presence. If a patient was not responsive to conservative care, I would confirm the diagnosis of nerve entrapment with an injection. To my surprise, many of my chronic heel pain patients did in fact have entrapment. (When this condition does not respond to conservative treatment, my procedure of choice is a release of the first branch of the lateral plantar nerve with a partial plantar fasciectomy). Pointing Out The Lack Of A Clear, Proven Treatment Protocol On another line of thought, I like to know how and why procedures work. I have yet to find an understandable and proven explanation of how and why ESWT works. First MPJ arthrodesis is one of my favorite procedures and I am reassured by the fact that it has not changed much since its inception in the 1890s. I understand the hows and whys of it. At the same time, I really dislike first MPJ implants based on my understanding of the hows and whys of that procedure. As with the disagreement among surgeons over ever changing implant designs, it seems that nobody can agree on the type of shockwave, pulses, settings and number of treatments to use. Do we use high-energy or low-energy waves? How many pulses? Should they be of variable settings or all the same? How many treatments does it take (multiple with low-energy or one with high-energy)? Consider this statement from an article by Boddeker, et. al, in Clinical Rheumatology: “Despite an extensive use of ESWT, treatment settings have not yet been established and the mechanisms of its postulated antinociceptive effects are still unclear.” I think that the unknown mechanism of action has led to this confusion and hinders establishment of therapeutic standards that could be implemented in providing a valid prospective, double-blind, long-term study that would shed some light on this procedure. Critical review of current studies reminds me of comparing apples to oranges. Take for example the much-publicized JAMA study by Buchbinder, which found “no evidence to support the beneficial effect on foot pain, function and quality of life of ultrasound-guided ESWT over placebo in patients with ultrasonic proven plantar fasciitis 6 and 12 weeks following treatment.” What does this low-energy study mean when compared to the Weils’ 2002 JFAS study, which shows an 83 percent success rate with high-energy treatment? I really don’t know but it does add to confusion with regard to efficacy. Because of this lack of definitive procedural protocol evaluation, the efficacy of ESWT really cannot be established. Boddeker’s article further states: “It is concluded that at this point the efficacy of ESWT can be neither confirmed nor excluded. Randomized and controlled clinical trials are required to adequately estimate the value of ESWT as a treatment for plantar fasciitis.” Raising Questions About Potential Complications And Long-Term Results Finally, what about potential complications and, especially, long-term success rates? There really are not any studies with more than a three- or four-year follow-up. While I realize that we are dealing with a new procedure, if we don’t know how and why ESWT works, how then can we predict the potential of recurrence rates? I feel that we cannot. I understand how orthotics and stretching provide long-term success rates for plantar fasciitis, but I am simply not sure how ESWT will prevent the re-straining of the plantar fascia if the patient is overweight, has poor foot mechanics, selects inappropriate shoe gear, has an excessively high activity level or works standing for long periods of time on hard surfaces. Only properly conducted patient trials over a longer period of time can answer these questions. One should consider the possibility of recurrence and discuss it with the patient during the consent process. Although the literature has reported few complications, periosteum detachments, small fractures of the inner surface of the cortex, neurologic symptoms, plantar fascial rupture when done following multiple cortisone injections, lateral column and peroneal tendon pain have been reported in the literature for high-energy treatment. While high-energy treatment seems to be more efficacious than low-energy treatment, it apparently is associated with more potential complications, leading to still more questions on the standard of therapy. The potential to cause compartment syndrome would also seem to be a valid concern when evaluating potential complications, though it is not specifically mentioned in the literature. Final Notes So what is the bottom line with ESWT? If I had chronic, unresponsive heel pain and I chose ESWT, several conditions would have to be met prior to my consent to having the procedure. First, I would have had to undergone adequate conservative treatment for at least six months. Second, Baxter’s neuritis would have to have been ruled out. Third, I would have to accept the fact that no one knows how or why the procedure works and what the long-term success and recurrence rates are. Finally, I would have to have a clear understanding that this is not an entirely benign procedure without potential complications. My patients deserve the same consideration that I would warrant and so should yours. Dr. DeHeer is a Fellow of the American College of Foot and Ankle Surgeons and is a Diplomate of the American Board of Podiatric Surgery. He is also the team podiatrist for the Indiana Pacers and the Indiana Fever. Dr. Offutt is a second-year resident at Winona Memorial Hospital in Indianapolis, Ind. Dr. Baker works out of the Wound Care Center at the aforementioned institution and is also in private practice in Indianapolis, Ind. Dr. Trent is in private practice in Park Ridge, Ill. References 1. Baxter DE, Thigpen CM. Heel pain-operative results. Foot and Ankle. 5: 16-25, 1984. 2. Boddeker IR, Schafer H, Haake M. Extracorporeal shockwave therapy (ESWT) in the treatment of plantar fasciitis - A Biomaterial Review. Clin Rhem. 20: 324-330, 2001. 3. Buchbinder R, Ptasznik R, Gordon J, Buchanaan J, Prabaharan V, Forbes A. Ultrasound-guided extracorporeal shock wave therapy for plantar fasciitis. JAMA 288(11): 1364- 1372, 2002. 4. Chen HS, Chen,LM, Huang TW. Treatment of painful heel syndrome with shock waves. Clin Ortho Related Research. 387: 41-46, 2001. 5. Cosentino, R, Falsetti P, Manca S, De Stefano R, Frati E, Frediana B, Baldi F, Selvi E, Marcolongo R. Efficacy of extracorporeal shock wave treatment in Calcaneal enthesophytosis. Ann Rheum Dis. 60: 1064-1067, 2001. 6. Maier M, Steinborn M, Schmitz C, Stabler A, Kohler S, Pfahler M, Durr HR, Refior HJ. Extracorporeal shock wave application for chronic plantar fasciitis associated with heel spurs: prediction of outcome by magnetic resonance imaging. J Rheumatol. 27: 2455-2462, 2000. 7. Ogden JA, Alvarez R, Levitt R, Cross GL, Marlow M. Shock wave therapy for chronic proximal plantar fasciitis. Clin Ortho Related Research. 387: 47-57, 2001. 8. Ogden JA, Alvarez RG, Marlow M. Shockwave therapy for chronic proximal plantar fasciitis: a meta-analysis. Foot & Ankle. 23(4): 301-307, 2002. 9. Peterson KS: Study treads on “shock wave” heel therapy; Controversial report finds no evidence treatment cuts pain. USA Today, p. D8, Sept. 18, 2002. 10. Rajkurmar P, Schmitgen GF. Shock waves do more than just crush stones: extracorporeal shock wave therapy in plantar fasciitis. Int J Clin Pract 56(10): 735-737, 2002. 11. Rompe JD, Schoellner MD, Nafe B. Evaluation of low-energy extracorporeal shock-wave application for treatment of chronic plantar fasciitis. JBJS. 84A(3): 335-341, 2002. 12. Weil Jr. LS, Roukis TS, Weil Sr. LS, Borrelli AH. Extracorporeal shock wave therapy for the treatment of chronic plantar fasciitis: indications, protocol, intermediate results, and a comparison of results to fasciotomy. J. Foot Ankle Surg. 41(3): 166-172, 2002.

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