Advertisement

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Electronic Letters to:

Musculoskeletal Imaging: Fang Zhu, Jeffrey E. Johnson, Christopher B. Hirose, and Kyongtae T. Bae Chronic Plantar Fasciitis: Acute Changes in the Heel after Extracorporeal High-Energy Shock Wave Therapy—Observations at MR Imaging Radiology 2005; 234: 206-210 [Abstract] [Full text] [PDF]

eLetters: Submit a response to this article

Electronic letters published:

Anything New?

Jan D. Rompe   (27 January 2005)

Anything New? 27 January 2005
Jan D. Rompe, Professor Dept. of Orthopaedic Surgery, Johannes Gutenberg University School of Medicine, Mainz, Germany Send letter to journal: Re: Anything New? rompe{at}mail.uni-mainz.de Jan D. Rompe	Editor: I read with interest the article by Dr Zhu and colleagues in the January issue of Radiology (1). The authors claim that in plantar fasciitis, imaging modalities such as magnetic resonance (MR) imaging can clarify some of the controversies regarding the effectiveness and mechanism of action of extracorporeal shock wave therapy (ESWT). I would like to raise the following four items for response: 1. The finding that an increase in soft-tissue edema is the most common acute response associated with ESWT is not surprising, as it is the typical unspecific manifestation of a posttraumatic reaction. It remains unclear how this finding might enhance assessment of the effectiveness of ESWT and how it would allow optimization of treatment. 2. Their additional observations that the heel spurs seen were not affected by ESWT and that the proximal plantar fascia was abnormally thick in these patients, with thickness not significantly affected by ESWT, are not new. I wonder what results the authors expected when they included only 12 patients in this trial. 3. They wrote that patients were treated in a hospital outpatient surgical suite and that general anesthesia was induced with use of either a face mask or a laryngeal mask airway. ESWT (total of 1500 shock waves at a power setting of 18 kV) was applied to the heel at the point of maximal intensity of heel pain. If patients were under general anesthesia, how was the point of maximal intensity of heel pain verified during the ESWT procedure? 4. Although they claimed to have used a high-energy treatment protocol, they found that bone marrow edema had increased in one case and had newly developed in another case. They hypothetized that this relatively small effect on bone marrow could be explained by the magnitude of the shock waves used. Following Ogden et al (2,3), Zhu et al defined 18 kV (equivalent to an energy flux density of 0.22 mJ/mm2) as high-energy treatment. In a recent study, we treated patients with an energy flux density of 0.18 mJ/mm2, defining this as low-energy treatment (4). I, therefore, question the labeling of the treatment concept of Zhu et al as high-energy therapy. The negligible bone marrow reaction described in the current study supports this, particularly when compared with changes after real high-energy treatment with an energy flux density of 0.9 mJ/mm2 (5-7). Why did not the authors discuss those references? Perhaps because J.E.J. had a financial interest through a partnership that owns and operates an extracorporeal shock wave device, OssaTron, and because one of the characteristics of the device touted in the Healthtronics advertising campaign is "high energy"? In summary, it may be said that the results of this trial do not provide any new knowledge. The authors, in an extremely small number of patients, described an unspecific phenomenon common to a posttraumatic situation. It is my firm opinion that they should have waited to publish their study until they had correlated pre- and post-ESWT MR imaging findings with clinical data, particularly long-term clinical data in a much larger cohort of patients. References 1. Zhu F, Johnson JE, Hirose CB, Bae KT. Chronic plantar fasciitis: acute changes in the heel after extracorporeal high-energy shock wave therapy—observations at MR imaging. Radiology 2005; 234:206-210. 2. Ogden JA, Alvarez R, Levitt R, Cross GL, Marlow M. Shock wave therapy for chronic proximal plantar fasciitis. Clin Orthop 2001; 387:47-59. 3. Ogden JA, Alvarez R, Levitt R, Johnson JE, Marlow M. Electrohydraulic high-energy shock-wave treatment for chronic plantar fasciitis. J Bone Joint Surg Am 2004; 86:2216-2228. 4. Rompe JD, Decking J, Schoellner C, Nafe B. Shock wave application for chronic plantar fasciitis in running athletes: a prospective, randomized, placebo-controlled trial. Am J Sports Med 2003; 31:268-275. 5. Maier M, Hausdorf J, Tischer T, et al. New bone formation by extracorporeal shock waves: dependence of induction on energy flux density. Orthopade 2004; 33:1401-1410. 6. Maier M, Freed JA, Milz S, Pellengahr C, Schmitz C. Detection of bone fragments in pulmonary vessels following extracorporeal shock wave application to the distal femur in an in-vivo animal model. Z Orthop Ihre Grenzgeb 2003; 141:223-226. 7. Maier M, Averbeck B, Milz S, Refior HJ, Schmitz C. Substance P and prostaglandin E2 release after shock wave application to the rabbit femur. Clin Orthop 2003; 406:237-245. Dr Bae and colleagues respond: We appreciate Dr Rompe's great interest in our work and his invigorating comments. Our responses to each of his comments are as follows: 1. We understand that much more extensive local acute changes have been observed by previous investigators (1) in laboratory animals after ESWT; however, some of these changes (such as edema of the proximal plantar fascia, calcaneal attachment site, and the soft tissues surrounding the plantar fascia insertion) have been observed in patients with chronic proximal plantar fasciitis before treatment. This is the first study we are aware of that examines patients prospectively before and after treatment with use of clinically relevant high-dose ESWT to the proximal plantar fascia. Some of the posttreatment changes are interesting and not as trivial as Dr Rompe perceived. The purpose of this imaging study was to characterize the MR imaging findings pre-and posttreatment, leaving the issues of how this information might enhance our assessment and optimize treatment to a later study in which clinical information is included. The study design and research plan were clearly explained in the Discussion section. 2. The observations that the thickness of the plantar fascia and the lack of significant change in the heel spur were important because high-dose ESWT had been associated with periosteal detachments and small fractures of the inner surface of the cortex in animals (2,3). Twelve patients is an adequate number to demonstrate the occurrence of these types of changes. The relevance of these findings is most important, however, when compared with the MR imaging appearance of these structures at 1 year after treatment (ongoing study). Dr Rompe claims that these observations "are not new." We wish he would cite a reference to substantiate his claim, instead of attempting to trivialize our study. 3. ESWT was delivered to the precise site of maximal intensity of pain (PMI) as noted by the patient immediately before the procedure. This PMI was localized and marked with an indelible pen by the treating physician (J.E.J.) on all patients in the anesthesia holding area just before the procedure. This area could be constantly referred to and monitored during application of the shock waves to ensure that the head of the ESWT device [AU: Correct?] was in constant contact with the PMI. 4. The characterizing of ESWT as either high or low dose is not yet well established. As Dr Rompe himself points out in one of his previous articles, "Indeed, there is no consensus so far as to how to differentiate low-energy from high-energy shock waves because multiple physical parameters are involved" (4). The "high-dose" ESWT that Dr Rompe describes in his article used an electromagnetic shock wave emitter (Sonocur Plus; Siemens, Erlangen, Germany) delivering an energy flux density of 0.16 mJ/mm2 (not 0.18 mJ/mm2 as he claims). The treatments in Dr Rompe's study were administered without analgesics or local, regional, or general anesthesia and were considered "unpleasant" by all subjects but less painful than administration of local anesthetic to the heel. No patient discontinued the study because of severe pain. In sharp contrast, the ESWT application in our subjects was delivered with an electrohydraulic shockwave emitter using spark gap technology (Ossatron; Healthtronics, Austin, Tex) and at 18 kV is equivalent to an energy density of 0.22 mJ/mm2. Our patients required a general anesthetic because of the severe pain associated with delivery of these shock waves to the heel. It is possible to administer this amount of sound wave energy to the heel with an ankle block regional anesthetic or extensive local anesthetic infiltration, since this was the method used during the multicenter FDA study protocol. In my experience and those of many of the FDA study coinvestigators, however, our patients disliked the incomplete pain relief afforded by the regional anesthetic and often complained of pain radiating proximally through the ankle and up the tibia. The "real" high-energy ESWT that Dr Rompe was referring to (5) is an energy level of 0.9 mJ/mm2 delivered to a laboratory animal by an electrohydraulic device (XL1; Dornier MedTech, Wessling, Germany). These shock waves represent over four times more energy than used in the patients in our study, which is a level not clinically applicable to plantar fasciitis with the current manufacturers'[AU: Should this be singular or plural?] recommended treatment guidelines based on the initial FDA study data for the Ossatron device. We agree with Dr Rompe that his study using ESWT from an electromagnetic device at an energy flux of 0.16 mJ/mm2 and requiring no anesthesia represents a low-energy shock wave treatment. We believe it is appropriate to describe our treatment as high-energy ESWT, given the higher effective energy level of 0.22 mJ/mm2. Furthermore, we are puzzled by Dr Rompe's implication that because one of us (J.E.J.) has a limited financial interest in the Ossatron device that was used at our institution to treat these patients, that we would in some way be inclined to be less intellectually honest and unbiased in the description and discussion of our results and in characterization of the Ossatron as a high-dose ESWT device. We have no interest financially or otherwise in Healthronics or any other shock wave device manufacturer. The issue of whether a high- or low-energy device is more efficacious is completely irrelevant to our current study. Our study was not designed to support or refute any claims by device manufacturers. Dr Rompe has made considerable scientific contributions in the field of shock wave therapy through his publications and leadership in the International Society for Musculoskeletal Shockwave Therapy (ISMST). However, we find the innuendo in his comments disappointing, especially from someone who is, like us, trying to increase our understanding of this exciting new technology. What we have reported is important. We have reported on the effects of high-dose shock waves to the proximal plantar fascia prospectively in 12 patients, comparing the same patient's pre- and posttreatment MR images so that each patient is an internal control, thereby allowing the changes observed to be evaluated in light of whatever preexisting changes may have been present in the plantar fascia and surrounding tissues. The focus of a future study, with a larger patient group, is to correlate the clinical response with the MR findings in each patient. References 1. Maier M, Steinborn M, Schmitz C, et al. Extracorporeal shock wave application for chronic plantar fasciitis associated with heel spurs: prediction of outcome by magnetic resonance imaging. J Rheumatol 2000; 27:2455-2462. 2. Ikeda K, Tomita K, Takayama K. Application of extracorporeal shock wave on bone: preliminary report. J Trauma 1999; 47:946-950. 3. Maier M, Freed JA, Milz S, Pellengahr C, Schmitz C. Detection of bone fragments in pulmonary vessels following extracorporeal shock wave application to the distal femur in an in-vivo animal model. Z Orthop Ihre Grenzgeb 2003; 141:223-226. 4. Rompe JD, Decking J, Schoellner C, Nafe B. Shock wave application for chronic plantar fasciitis in running athletes. A prospective, randomized, placebo-controlled trial. Am J Sports Med 2003; 31:268-275. 5. Maier M, Averbeck B, Milz S, Refior HJ, Schmitz C. Substance P and prostaglandin E2 release after shock wave application to the rabbit femur. Clin Orthop 2003:237-245.