OrthoNeuroSpine & Pain Institute

BACKGROUND:

The use of extracorporeal shock wave therapy for the treatment of lateral epicondylitis is controversial. The purpose of this study was to evaluate the use of extracorporeal shock wave therapy without local anesthesia to treat chronic lateral epicondylitis.

METHODS:

One hundred and fourteen patients with a minimum six-month history of lateral epicondylitis that was unresponsive to conventional therapy were randomized into double-blind active treatment and placebo groups. The protocol consisted of three weekly treatments of either low-dose shock wave therapy without anesthetic or a sham treatment. Patients had a physical examination, including provocation testing and dynamometry, at one, four, eight, and twelve weeks and at six and twelve months after treatment. Radiographs, laboratory studies, and electrocardiograms were also evaluated prior to participation and at twelve weeks. A visual analog scale was used to evaluate pain, and an upper extremity functional scale was used to assess function. Crossover to active treatment was initiated for nonresponsive patients who had received the placebo and met the inclusion criteria after twelve weeks.

RESULTS:

A total of 108 of the 114 randomized patients completed all treatments and the twelve weeks of follow-up required by the protocol. Sixty-one patients completed one year of follow-up, whereas thirty-four patients crossed over to receive active treatment. A significant difference (p = 0.001) in pain reduction was observed at twelve weeks in the intent-to-treat cohort, with an improvement in the pain score of at least 50% seen in 61% (thirty-four) of the fifty-six patients in the active treatment group who were treated according to protocol compared with 29% (seventeen) of the fifty-eight subjects in the placebo group. This improvement persisted in those followed to one year. Functional activity scores, activity-specific evaluation, and the overall impression of the disease state all showed significant improvement as well (p < 0.05). Crossover patients also showed significant improvement after twelve weeks of active treatment, with 56% (nineteen of thirty-four) achieving an improvement in the pain score of at least 50% (p < 0.0001).

CONCLUSIONS:

These results demonstrate that low-dose shock wave therapy without anesthetic is a safe and effective treatment for chronic lateral epicondylitis.

Repetitive low-energy shock wave application without local anesthesia is more efficient than repetitive low-energy shock wave application with local anesthesia in the treatment of chronic plantar fasciitis

Rompe JD, Meurer A, Nafe B, Hofmann A, Gerdesmeyer L.

Background:

It remains unclear whether application of local anesthesia (LA) interferes with clinical efficacy of extracorporeal shock wave therapy (ESWT) for chronic plantar fasciitis.

Aims: To evaluate the effect of local anesthesia on the clinical outcome after repetitive low-energy ESWT for chronic plantar fasciitis.

Methods:

Eighty-six patients with chronic plantar fasciitis were randomly assigned to receive either low-energy ESWT without LA, given weekly for three weeks (Group I, n=45; 3 x 2000 pulses, total energy flux density per shock 0.09 mJ/mm2) or identical ESWT with LA (Group II, n=41). Primary outcome measure was: Reduction of pain from baseline to month 3 post-treatment in a pain numeric rating scale [0-10 points] during first steps in the morning, evaluated by an independent blinded observer. Calculations were based on intention-to-treat.

Results:

No difference was found between the groups at baseline. At 3 months, the average pain score was 2.2+/-2.0 points for patients of Group I, and 4.1+/-1.5 points for patients of Group II. The mean between-group difference was 1.9 points (95% CI: [1.1-2.7 points]; P<.001). Significantly more patients of Group I achieved 50% reduction of pain compared to Group II (67% vs 29%, P<.001).

Conclusions: ESWT as applied should be done without LA in patients suffering from chronic heel pain. LA applied prior treatment reduced the efficiency of low-energy ESWT.

Arch Phys Med Rehabil. 2013 Mar 13. pii: S0003-9993(13)00205-0. doi: 10.1016/j.apmr.2013.01.030. [Epub ahead of print]

Clinical improvement and resorption of calcifications in calcific tendinitis of the shoulder after shock wave therapy at 6 months follow-up. A systematic review and meta-analysis.

Ioppolo F, Tattoli M, Di Sante L, Venditto T, Tognolo L, Delicata M, Rizzo RS, Di Tanna G, Valter S.

Source: Physical Medicine and Rehabilitation Unit, Azienda Policlinico Umberto I, Rome, Italy. Electronic address: francescoioppolo@yahoo.it.

Abstract

OBJECTIVE: To evaluate the effect of the Shock wave therapy (SWT) on functional improvements and reduction of pain, and what is rate of disappearance of calcifications after therapy at 6 month follow up.

DATA SOURCES: Articles were searched from the COCHRANE LIBRARY, MEDLINE, EMBASE, CINAHL and OVID DATABASE.

STUDY SELECTION:We included randomized controlled trials from 1992 to 2011 and their quality was assessed using the PEDro scale.

DATA EXTRACTION: Studies were evaluated by two independent reviewers for their methodological quality. If disagreement arose the plan was that it would be settled by a third reviewer. Then data were extracted and cross-checked for accuracy. The reviewers were not blinded to the authors of the articles.

DATA SYNTHESIS: In studies of Hearnden, Hsu, Cacchio and Cosentino the resorption of calcifications was evaluate using meta-analysis because in them there were two groups of treatment, while the studies of Peters and Gerdesmeyer were analyzed descriptively because they considered three groups of treatment. Fixed and random effects models were used to meta-analyze total and partial resorption ratios and to assess heterogeneity the I2 statistics were calculated.

CONCLUSIONS: We found a clinical improvement with a pooled Total Resorption Ratio of 27.19 (95% CI: 7.20-102.67) and a pooled Partial Resorption Ratio of 16.22 (95% CI: 3.33-79.01). SWT increases shoulder function, reduces pain, and it is effective in dissolving calcifications. These results were maintained over the following 6 months.

Am J Phys Med Rehabil. 2013 Apr 2.

Effectiveness of Extracorporeal Shock Wave Therapy in Chronic Plantar Fasciitis: A Meta-analysis.

Source: Dizon JN, Gonzalez-Suarez C, Zamora MT, Gambito ED.

From the Department of Physical Medicine and Rehabilitation, University of Santo Tomas Hospital, Manila, Philippines.

Abstract

The objective of this study was to evaluate the effectiveness of extracorporeal shock wave therapy (ESWT) in treating chronic plantar fasciitis. An online database search was conducted for studies using ESWT in managing chronic plantar fasciitis. Eleven high-quality randomized controlled trials were included in the meta-analysis and showed that ESWT was more effective in reducing morning pain (weighted mean difference, -0.77 [95% confidence interval {CI}, -1.30 to -0.25]; odds ratio, 0.65 [95% CI, 0.42-1.00]). Moderate-intensity ESWT was more effective in decreasing overall and activity pain (weighted mean difference, -6.6 [95% CI, -6.74 to -6.46], and weighted mean difference, 0.47 (95% CI, 0.30-0.74). Both moderate- and high-intensity ESWT were more effective in improving functional outcome, with odds ratios of 0.51 (95% CI, 0.30-0.84) and 0.47 (95% CI, 0.29-0.75). The adverse effects that were seen more in ESWT were pain on the calcaneal area and calcaneal erythema. This study concludes that moderate- and high-intensity ESWT were effective in the treatment of chronic plantar fasciitis.

Radial extracorporeal shock wave therapy improves recalcitrant plantar fasciitis symptoms.

OrthoEvidence Advanced Clinical Evidence Report. In: Ortho Evidence. Created Oct 01, 2011. Last modified Oct 01, 2012. Retrieved Jul 26, 2013 from http://www.myorthoevidence.com/?section=15&id=2807.

Radial Extracorporeal Shock Wave Therapy Is Safe and Effective in the Treatment of Chronic Recalcitrant Plantar Fasciitis

Results of a Confirmatory Randomized Placebo-Controlled Multicenter Study

Ludger Gerdesmeyer,MD, PhD, Carol Frey, MD, Johannes Vester, PhD,Markus Maier, PhD, Lowell Weil Jr, DPM, Lowell Weil Sr,DPM, Martin Russlies, PhD,John Stienstra,DPM, Barry Scurran, DPM, Keith Fedder, MD, Peter Diehl, MD,Heinz Lohrer, MD, Mark Henne, MD, and Hans Gollwitzer, MDFrom the Department of Orthopedic and Traumatology, Technical University Munich, KlinikumRechts der Isar, Germany, the Department of Joint Arthroplasty and Clinical Science, MareClinic, Kiel, Germany, Orthopaedic Foot and Ankle Center, Manhattan Beach, California, DVData Analyses and Study Planning, Biometrics in Medicine, Gauting, Germany, the Departmentof Orthopedics, Ludwig Maximilian University, Munich, Germany, the Weil Foot and Ankle Institute, Des Plaines, Illinois, University Schleswig Holstein, Campus Lübeck, Lübeck,Germany, the Department of Podiatry, The Permanente Medical Group Inc, Union City,California, the Department of Orthopedics, University Rostock, Rostock, Germany, and the Institute of Sportsmedicine, Frankfurt am Main, Germany

Background: Radial extracorporeal shock wave therapy is an effective treatment for chronic plantar fasciitis that can be administered to outpatients without anesthesia but has not yet been evaluated in controlled trials.

Hypothesis: There is no difference in effectiveness between radial extracorporeal shock wave therapy and placebo in the treatment of chronic plantar fasciitis.

Study Design: Randomized, controlled trial; Level of evidence, 1.

Methods: Three interventions of radial extracorporeal shock wave therapy (0.16 mJ/mm2; 2000 impulses) compared with placebo were studied in 245 patients with chronic plantar fasciitis. Primary endpoints were changes in visual analog scale composite score from baseline to 12 weeks’ follow-up, overall success rates, and success rates of the single visual analog scale scores (heel pain at first steps in the morning, during daily activities, during standardized pressure force). Secondary endpoints were single changes in visual analog scale scores, success rates, Roles and Maudsley score, SF-36, and patients’ and investigators’ global judgment of effectiveness 12 weeks and 12 months after extracorporeal shock wave therapy.

Results: Radial extracorporeal shock wave therapy proved significantly superior to placebo with a reduction of the visual analog scale composite score of 72.1% compared with 44.7% (P = .0220), and an overall success rate of 61.0% compared with 42.2% in the placebo group (P = .0020) at 12 weeks. Superiority was even more pronounced at 12 months, and all secondary outcome measures supported radial extracorporeal shock wave therapy to be significantly superior to placebo (P < .025, 1- sided). No relevant side effects were observed.

Conclusion: Radial extracorporeal shock wave therapy significantly improves pain, function, and quality of life compared with placebo in patients with recalcitrant plantar fasciitis.

Keywords: heel pain; plantar fasciitis; shock wave; lithotripsy; radial extracorporeal shock wave therapy

The American Journal of Sports Medicine, Vol. X, No. X

Focus

Shock wave therapy

M. Gleitz, U. Dreisilker, R. Rädel

Orthopedic trigger point shock wave therapy with focused and radial shock waves: a review of the current situation

Orthopedic Surgery, Dr. Gleitz, Luxemburg Introduction

Myofascial pain syndromes are among the most frequent orthopedic disorders. However, efforts to treat these syndromes often show limited success. This is confirmed by the multitude of competing therapy options available today.

According to the theory established by Travell and Simons in their Trigger Point Manual (1992), muscular trigger points are one of the main causes of myofascial pain. Clinical observations and experimental examinations conducted by Travell and Simons have corroborated this theory, demonstrating that muscular trigger points cause diverse functional disorders. These findings coincide with the information provided by patients on pain development and progression. Despite the impressively detailed description of muscle- associated pain syndromes in the Trigger Point Manual (1992), trigger point therapy is still only rarely used in orthopedic practice.

The role of trigger points in causing pain and discomfort is evidenced by the clinical symptoms they may generate: formation of muscle knots with local and referred pain, muscular taut bands, twitch response, reduced range of motion (ROM) of joints, formation of satellite trigger points, development of pseudoradicular dysesthesia and vegetative accompanying reactions.

According to Simons' "integrated hypothesis of trigger point formation" (1996), trigger points are produced by muscular motor end-plate dysfunction which may be caused by various mechanisms, such as acute mechanical overstrain, including trauma, chronic overstrain caused by monotony of motion (repetitive strain injury), poor posture, cold, emotional distress, or result from articular, neurogenic, visceral, hormonal or remote muscular disorders.

The increased calcium release resulting from the above lesions causes a permanent contracture of the actin/myosin filaments (abnormally contracted sarcomeres) under the dysfunctional end-plate and thus leads to increased energy consumption. At the same time, the capillary compression caused by the contraction knots produces local ischemia. The concurrence of these two factors causes a local energy crisis. Local ischemia induces the release of bradykinine in the tissue and of other substances sensitizing muscle nociceptors and increases the tenderness to pressure of the trigger points (allodynia, hyperalgesia). Ischemia causes additional motor end-plate dysfunction and thus creates a vicious circle. Muscles affected by trigger points exhibit changed properties. Apart from the typical contractures, these muscles are characterized by a reduced development of muscular force, delayed relaxation after activity, tendency to spasm and decreased fine motor skills (coordination). These conditions explain the muscles' susceptibility to additional lesions (muscle strain, torn fibers, etc.).

Trigger points cause alterations in the nervous system that contribute to the chronification of pain. These alterations include peripheral sensitization of muscle nociceptors, increased number of nociceptors, activation of the axon reflex, central sensitization (synaptic transmission) and failure of inhibiting interneurons of the supraspinal descending antinociceptive system (8).

If trigger points continue to exist over a prolonged period of time, they may activate satellite trigger points in other muscles. These satellite trigger points will develop their own pain patterns and functional disorders. This will eventually induce myopathic chain reactions (2)

with complex pain patterns and secondary structural alterations in the form of insertional tendinopathies (3).

The typical referred pain caused by trigger points is explained on the basis of the "convergence projection theory" (13). This theory postulates that the information from diverse peripheral receptors in various tissue regions is centrally transmitted through a common segmental dorsal horn neuron, which causes a misperception of pain in the patient. If doctors use an approach that is entirely based on classical neurological innervation patterns, this phenomenon makes it extremely difficult to localize the pain origin.

Muscular trigger points require specific treatment owing to their low self-healing capacity. One of the most effective therapy procedures is the application of strong mechanical pressure to the muscle knots (gelotripsy) followed by muscle stretching (17). The following reasons for the efficacy of this therapy approach are discussed: resolution of permanent actin/myosin contractures, improvement of local circulation (reactive hyperemia) along with the elimination of the ischemia-induced energy crisis (8) and reduction in the concentration of vasoneuroactive substances.

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Summary

Key words: ESWT – trigger points – myofascial pain syndrome

Orthopedic trigger point shock wave therapy with focused and radial shock waves

The trigger point therapy of Travell and Simons is the starting point for the diagnosis and treatment of myofascial pain syndromes. As trigger points are difficult to localize and trigger point therapy has only limited efficiency, this therapy option is rarely used in practice.

Shock wave application to trigger points represents a new therapy approach in trigger point treatment. The combined use of radial and focused shock waves allows effective local trigger point treatment as well as shock wave application to a wider muscle surface area. Focused shock waves can be used to induce referred pain for precise trigger point localization.

The experience gathered by the authors has shown that a wide range of functional disorders can be treated with trigger point shock wave therapy. The therapy success is based on recognizing muscular trigger points as the origin of pain, which sets this therapy apart from conventional treatment methods.

No scientific evidence is available to date explaining the precise mode of action of shock waves applied to muscular trigger points.

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Trigger point shock wave therapy

Application of shock waves to muscles

Since the mid-1990s, various publications have discussed the possibility of muscle treatment with low-energy focused shock waves (4, 5, 7, 14) as an alternative to manual therapy. The common result of the treatments conducted is a reduction of muscle tone along with a diminished extent of muscle shortening.

Since the late 1990s, muscular trigger points have also been treated with radial shock waves (rESWT) with a tissue penetration depth of 20 to 25 mm. While no scientific evidence is available to date explaining the exact mechanism of radial shock waves, extensive molecular and biochemical research has been conducted into the mode of action of focused shock waves (6, 18). In fact, focused shock waves induce a reduction of nociceptive fibers, whereas radial shock waves seem to have a counter-irritation and pain modulating effect

through GABAergic interneurons in the dorsal horn. In addition to this action, the pressure and vibrations of radial shock waves improve blood circulation and lymphatic drainage.

Indications and contraindications

Trigger point shock wave therapy can be used to treat all acute and chronic myofascial disorders, provided that no primary disease is present that causes the muscular trigger points and prevents their elimination. In the latter case, trigger points and entire trigger point chains must be seen as part of complex disease patterns such as visceral and psychic diseases, craniomandibular dysfunctions or foot deformations with proprioceptive control disorders. Such conditions should be treated by conducting a causal therapy of the primary disease on the one hand and by eliminating the trigger point syndromes on the other hand. Trigger point therapy is most successful if the primary disease causing the trigger point symptoms can be entirely cured or if its intensity can at least be minimized. Despite causal therapy, trigger points are frequently found to persist or to develop independently. This condition, which is referred to as autonomous trigger point syndrome, can be well treated with trigger point shock wave therapy.

One example for this phenomenon is pseudosciatica after successful discectomy. The trigger points in the gluteal muscles, external rotators (e.g. piriformis muscle) and quadratus lumborum muscle that were activated by the original nerve compression continue to persist despite the fact that the root compression has been eliminated. Successful resolution of these trigger points is only possible by means of trigger point therapy.

Examples of poor indications for trigger point therapy are genuine radicular lesions or advanced spinal or foraminal stenosis in the lower lumbar segments, also with secondary trigger points in the gluteal or hip muscles. Although trigger point therapy of these conditions frequently provides alleviation of pain, this effect will only be of short duration owing to the dominant nature of the nerve compression.

Trigger point therapy is not successful in the treatment of the following disorders: all types of rheumatism with inflammatory activity, severe fibromyalgia and severe vegetative dystonia. General contraindications for trigger point therapy include malignant tumors, primary myopathies, serious rheumatic diseases (e.g. rheumatic polymyalgia) or treatment areas above vulnerable structures. During shock wave therapy, it is crucial that pulmonary tissue is not within the target area of focused shock waves.

Relative contraindications include pregnancy and anticoagulant therapy.

Radial or focused shock waves?

The combined use of focused and radial shock waves is one of the recent developments in trigger point therapy. With this approach, focused shock waves are used to treat both tendon insertions and muscles.

The application of focused shock waves to tendon insertions is recommended whenever muscle shortening caused by trigger points has resulted in secondary insertional tendinopathies. In these cases, treatment of the muscular trigger points alone would not be sufficient to cure the disease as the tendon irritation is often responsible for the dominant pain symptoms and would persist as an independent cause of pain even after successful muscular trigger point therapy.

Focused shock waves applied to muscles are used for diagnostic and therapeutic purposes. On the one hand, they ensure precise localization of the trigger points as the typical referred pain can be induced more reliably than during manual examination. On the other hand, focused shock waves are used for the local treatment of individual trigger points. Thanks to the minimal irritation they cause, focused shock waves can also be used for the trigger point therapy of extremely painful muscles.

Radial shock waves are used for the local treatment of muscular trigger point areas and, subsequently, for smoothing the residual muscle. This method allows large muscle regions to be treated with radial shock waves.

When treating extremely painful myofascial syndromes, only focused shock waves should be used during the initial therapy sessions. Treatment can then be continued with radial shock waves at low therapy pressure (1.6 – 1.8 bar).

Promising experience has been gathered recently in the use of defocused shock waves for the treatment of trigger points or insertional tendinopathies. "Defocused" means that the generated waves are applied to the tissue not in a single spot but over a wider surface area.

Therapy planning

The muscles to be treated are selected on the basis of the following criteria: patient's indication of pain, diagnosis of muscle knots (manually or with radial shock waves), possible provocation of referred pain by palpation pressure or with focused shock waves and, where possible, ROM testing to identify the muscles affected by reductions in the range of motion. The anamnesis and description of the pain with respect to the pain location and referral are of special importance. Detailed knowledge of muscle-specific pain patterns, which deviate entirely from classical neurological innervation patterns, allows early identification of the muscles involved in the pain syndromes. Descriptions of pain provided by patients, which do not make sense under neurological aspects, prove astonishingly coherent and informative when considered under trigger point aspects, all the more so because trigger points can also be responsible for dysesthesia, coordination disorders and loss of strength.

Knowledge of the muscle-specific pain referral described by Travell and Simons (1992) represents an indispensable requirement for every therapist. Increasing experience in trigger point therapy, especially in the use of focused shock waves, has shown that pain referral patterns and the location of muscle knots vary in each patient and need to be identified by accurate examination.

Localization of trigger points

The induced referred pain is a major criterion for the selection of the therapy region. Strong manual pressure is exerted on the muscle knots to cause referred pain. Focused shock waves can be applied to induce referred pain more easily and accurately. Depending on the muscle thickness and depth of the trigger point areas, focused shock waves with variable penetration depth are applied at an energy level of between 0.05 and 0.25 mJ/mm2.

Radial shock waves are less suitable for the localization of trigger points on the basis of referred pain. Radial shock waves are rather used to identify indurations inside the muscles. This is done by moving the applicator over a large muscle area during the therapy.

Therapy procedure

The trigger points to be treated are selected according to the criteria of short-term or long- term reduction of the pain symptoms. Therapy is started by treating the active trigger points which are responsible for spontaneous current pain or pain on exertion.

This is followed by the treatment of satellite trigger points in the area of pain referral. Similarly to secondary trigger points in the functional muscle chains of antagonists and synergists, satellite trigger points are responsible for the chronification process if they persist for a prolonged period of time.

Insertional tendonitis, which Travell and Simons (1992) describe as peripheral trigger points, should be given special attention. These trigger points must be treated with focused shock waves. However, contrary to the treatment of muscular trigger points, a reduction in pain is only perceived several weeks after the therapy. This is due to the slowness of the induced physiological repair mechanisms. In this context, the energy flux density is of major importance. Experience has shown that shock waves should be applied at a low energy level in order not to affect the cell recovery potential, that is the useful neurogenic immediate tissue response. Since treatment is performed on a biological system, the therapy intervals between the individual sessions should not be too short (at least 1 to 2 weeks) and the

number of therapy sessions should be limited. It is also crucial that no local anesthetic be used prior to shock wave application (12).

Accompanying therapies

In principle, no accompanying therapies are required to achieve the desired therapy success. However, shock wave therapy can be supported by trigger point stretching in fiber direction. In the presence of severe joint blockage, the blockage may loosen as a result of muscle relaxation after shock wave therapy. If this is not the case, manual therapy can be performed to eliminate the blockage after the first two or three trigger point therapy sessions and after muscle tension has started to decrease. Additional therapies, such as massaging, should not be used.

Muscle strengthening therapy can be performed one to two days after the trigger point therapy. However, it is crucial that this therapy not be performed with maximum force or at the point of maximum muscle shortening.

In the treatment of chronic pain syndromes, ibuprofen or paracetamol should be administered at the beginning of the trigger point therapy to relieve the pain.

Treatment parameters and duration

The energy flux density of focused shock waves used in muscular trigger point therapy is between 0.05 and 0.25 mJ/mm2. Higher energy levels should not be used to avoid tissue damage (11). Judging by the latest scientific research results, the shock wave frequency applied to the trigger point should not exceed 4 Hz.

The energy flux density (mJ/mm2) is selected on the basis of the thickness and depth of the muscle and the patient's indication of pain during localization of the trigger points and provocation of referred pain. The energy flux density should be selected in such a way that the pain induced by the shock waves can still be well tolerated by the patient. Generally speaking, the energy level can be increased after each therapy session as the pain perceived during shock wave application gradually decreases if the therapy progresses smoothly.

The same applies to radial shock waves. The therapy pressure of radial shock waves varies between 1.6 and 4 bar, depending on the shock transmitter size and the patient's indication of pain. Shock transmitters with a small surface should be used with extreme caution owing to the high peak pressures they may generate. Judging by our experience, such shock transmitters are generally not required for the muscles to be treated. The pressure applied should be adequate for the tissue properties to avoid hematomas. The shock wave frequency is 10 to 15 Hz, where the 15 Hz frequency is generally perceived as causing less pain. This effect may be attributable to the physiological intrinsic muscle oscillation stimulated by the radial shock waves.

In the combined use of focused and radial shock waves in trigger point therapy, the trigger points are first treated locally, applying 200 to 400 focused shock waves.

This step is followed by muscle smoothing of the agonists, antagonists and synergists with the radial shock wave transmitter, applying 3000 to 4000 radial shock waves.

If muscles are treated with radial shock waves alone, the trigger point area is treated locally with 500 to 1000 shock waves and without applying manual pressure. This step is then followed by muscle smoothing with up to 4000 shock waves at a frequency of 15 Hz, in accordance with the stretch-and-spray technique developed by Travell and Simons (1992).

Treatment frequency

A therapy frequency of one session per week has shown to be ideal for most patients. These intervals enable the muscles to recover from the irritation, which may initially persist for up to three days. Shorter intervals might cause additional muscle irritation before the irritation from the previous session has actually disappeared and thus increase pain. Insertional tendonitis should not be treated at shorter intervals in order not to affect the aforementioned

regeneration potential that results from the local neurogenic tissue response. Pain modulation aspects, too, suggest that the treatment intervals in trigger point shock wave therapy, similarly to acupuncture, should not be too short. The following general principle applies: longer therapy intervals and lower treatment intensities should be used for more serious and chronic pain syndromes.