No influence of low-energy extracorporeal shock wave therapy (ESWT) on spinal nociceptive systems

Application of extracorporeal shock wave therapy in nervous system diseases: A review

Neurological disorders are one of the leading causes of morbidity and mortality worldwide, and their therapeutic options remain limited. Recent animal and clinical studies have shown the potential of extracorporeal shock wave therapy (ESWT) as an innovative, safe, and cost-effective option to treat neurological disorders. Moreover, the cellular and molecular mechanism of ESWT has been proposed to better understand the regeneration and repairment of neurological disorders by ESWT. In this review, we discuss the principles of ESWT, the animal and clinical studies involving the use of ESWT to treat central and peripheral nervous system diseases, and the proposed cellular and molecular mechanism of ESWT. We also discuss the challenges encountered when applying ESWT to the human brain and spinal cord and the new potential applications of ESWT in treating neurological disorders.

How to report parameters and procedures for shockwave therapy in musculoskeletal disorders: A narrative review

Shockwave therapy (SWT) has been successful in the management of musculoskeletal conditions. The limitations of the use of SWT in clinical practice regard a lack of familiarity with the device and the lack of uniformity in information reported in scientific publications. Standardization in the reporting of these parameters could facilitate the reproduction and interpretation of data in future studies. Most studies fail to offer a detailed description of the parameters. Therefore, the aim of the present paper is to prepare a report on how to standardize the presentation of this information and serve a reference guide to report physical parameters and procedures of SWT when used on patients with musculoskeletal disorders. The terms were selected from the Medical Subject Headings database of controlled vocabulary. An extensive process of systematic searching of databases was performed, after which experts met and discussed on the main findings, and a consensus was achieved. SWT parameters were described, including the physiological meaning and clinical relevance of each parameter. Also, the description of patient and equipment positioning was added. The consensus-based guideline on how to report SWT parameters for the treatment of musculoskeletal conditions was developed to help clinicians and researchers.

Molecular Mechanisms Underlying the Pain-Relieving Effects of Extracorporeal Shock Wave Therapy: A Focus on Fascia Nociceptors

In recent years, extracorporeal shock wave therapy (ESWT) has received increasing attention for its potential beneficial effects on various bone and soft-tissue pathologies, yielding promising outcomes for pain relief and functional recovery. In fact, ESWT has emerged as an alternative, non-invasive, and safe treatment for the management of numerous musculoskeletal disorders, including myofascial pain syndrome (MPS). In particular, MPS is a common chronic painful condition, accounting for the largest proportion of patients affected by musculoskeletal problems. Remarkably, sensory innervation and nociceptors of the fascial system are emerging to play a pivotal role as pain generators in MPS. At the same time, increasing evidence demonstrates that application of ESWT results in selective loss of sensory unmyelinated nerve fibers, thereby inducing long-lasting analgesia. The findings discussed in the present review are supposed to add novel viewpoints that may further enrich our knowledge on the complex interactions occurring between disorders of the deep fascia including changes in innervation, sensitization of fascial nociceptors, the pathophysiology of chronic musculoskeletal pain of MPS, and EWST-induced analgesia. Moreover, gaining mechanistic insights into the molecular mechanisms of pain-alleviating effects of ESWT may broaden the fields of shock waves clinical practice far beyond the musculoskeletal system or its original application for lithotripsy.

Effectiveness of extracorporeal shock wave therapy in patients with tennis elbow: A meta-analysis of randomized controlled trials

BACKGROUND

The aim of the present study was to investigate the effectiveness of Extracorporeal Shock Wave (ECSW) in the treatment of lateral epicondylitis (LE) of humerus.

HYPOTHESIS

ECSW therapy in people with LE effectively reduces the pain and gains functional rehabilitation.

MATERIALS/METHODS

Databases of PubMed, EMBASE, Web of Science and the Cochrane Library from inception to April 2020 was searched to identify all relevant RCTs comparing ECSW therapy with any other conservative treatment, including injection and local anesthetic versus placebo or control in patients aged 18 with LE. The primary outcome is the mean overall pain score at 12 weeks after treatment. Another secondary outcome mainly included Thomsen test, 50% pain reduction, grip strength and adverse effect at 12 weeks after treatment.

RESULTS

Nine studies were included in the meta-analysis. Compared with the placebo group, ECSW cannot significantly reduce the pain score (mean deviation [MD] = -4.23, 95% confidence interval [CI]: -8.78 to 0.32, P = .07), but make more people acquire 50% pain reduction (MD = 1.38, 95% CI: 1.09 to 1.75, P = .008). There was no significant difference between ECSW and control in decreasing the pain score of Thomsen test (MD = -3.22, 95% CI: -14.06 to 7.62, P = .56). ECSW was more effective in Grip strength as compared with control at 12 weeks-3 months (MD = 3.52, 95% CI: 2.43 to 4.60, P < .00001) CONCLUSIONS:: Results suggested that ECSW cannot effectively reduce the mean overall pain, but it showed more people acquire 50% pain reduction and might be a better option for the treatment of LE. Because of study limitations, additional high level of evidence, more rigorously designed large-samples and high-quality randomized controlled trials are needed to guide clinical practice.

[Extracorporal shock wave therapy for the treatment of pseudarthrosis : New experiences with an old technology]

BACKGROUND

Between 5 and 10 % of all fractures show disturbed healing or nonunion formation. Extracorporeal shock wave therapy (ESWT) has been described as a non-surgical treatment option. Even though the outcome has shown promising results, the procedure is not commonly used in clinical practice. The purpose of this study was to analyze the union rate of pseudarthrosis and the cost savings after ESWT.

METHODS

In this study 42 nonunions were treated with shock waves (LithSpaceOrtho, JenaMedtech). The follow up examinations were performed over a period of six months. Outcome measurement included radiological fracture union and pain (VAS). The study group contained 39 pseudarthrosis in the six-week follow-up (93 %), 41 after three months (98 %) and 41 after six months (98 %).

RESULTS

After six weeks, 13 % of patients showed fracture union. After three months 61 % and after six months 73 % of the fractures were completely healed. The fracture healing was significantly lower in older nonunions. All patients presented significantly lower pain levels six weeks after ESWT. Shock wave treatment of all 42 pseudarthrosis made up less than one quarter of the overall operative costs.

CONCLUSION

We established the ESWT as an important treatment option for fracture nonunion in our clinic. Considering the selection of patients in this study with a high mean time from injury to ESWT and multiple prior operations, the fracture healing rate of 73 % after ESWT is comparable with operative healing rates of nonunions. Further prospective, randomized and controlled studies are needed to show the effectiveness of ESWT in the treatment of nonunions on a higher level of evidence and to identify pseudarthrosis that particularly responds to the EWST.

A review of the cellular and molecular effects of extracorporeal shockwave therapy

Extracorporeal shockwave therapy (ESWT) is a novel therapeutic modality and its use in promoting connective tissue repair and analgesic effect has been advocated in the literature. It is convenient, cost-effective, and has negligible complications; it therefore bypasses many of the problems associated with surgical interventions. This paper reviews the proposed mechanisms of action in promoting tissue repair and regeneration as well as analysing its efficacy providing an analgesic effect in clinical applications. Further research will be required to not only identify the underlying mechanisms more precisely, but will also be critical for ensuring consistency across the literature so that the most beneficial treatment protocol can be developed. Extracorporeal shockwave therapy stands as a promising alternative modality in promoting tissue repair.

ESWT for tendinopathy: technology and clinical implications

PURPOSE

The general consensus that tendinopathy, at least in the chronic stage, is mainly a degenerative condition and inflammation plays a minor role has led to a shift from treatments that target inflammation towards treatment options that promote regeneration. One of these treatments is extracorporeal shockwave therapy (ESWT), a physical therapy modality that uses pressure waves to treat tendinopathy. This review was undertaken to give an overview of the literature concerning this treatment, and special attention is given to the differences between focused and radial ESWT.

METHODS

A narrative description of wave characteristics, generation methods and in vitro effects of ESWT is given. The literature on ESWT as a treatment for one common tendinopathy, patellar tendinopathy, was systematically reviewed.

RESULTS

Waves that are generated for focused and radial ESWT have very different physical characteristics. It is unclear how these characteristics are related to clinical effectiveness. Studies into the biological effects of ESWT have mainly used focused shockwave therapy, showing a number of effects of shockwaves on biological tissue. The systematic review of studies into the clinical effects of ESWT for patellar tendinopathy showed conflicting evidence for its effectiveness.

CONCLUSION

Physical characteristics of focused and radial waves differ substantially, but effect on clinical effectiveness is unclear. Whereas in vitro studies often show the effects of ESWT on tendon tissue, results of clinical studies are inconsistent. Based on the review of the literature, suggestions are given for the use of ESWT in clinical practice regarding timing and treatment parameters.

Radiofrequency microtenotomy for the treatment of plantar fasciitis shows good early results

BACKGROUND

Microtenotomy coblation using a radiofrequency (RF) probe is a minimally invasive procedure for treating chronic tendinopathy. It has been described for conditions including tennis elbow and rotator cuff tendinitis. There have been no studies to show the effectiveness of such a procedure for plantar fasciitis.

METHODS

14 Patients with plantar fasciitis with failed conservative treatment underwent TOPAZ RF treatment for their symptoms between 2007 and 2008. The RF-based microdebridement was performed using the TOPAZ Microdebrider device (ArthroCare, Sunnyvale, CA). There were 6 men and 8 women with an average age of 44.0 years (23-57). There were 15 feet, with 6 right and 9 left feet. They were followed up for up to 6 months thereafter. Pre-operative, 3 and 6 months post-operative AOFAS ankle-hindfoot and SF-36 scores were analysed.

RESULTS

There was a significant improvement in mean pre-operative, post-operative 3- and 6-month AOFAS hindfoot scores from 34.47 to 69.27 and 71.33 (p=0.00) respectively. There was a significant decrease in SF-36 for bodily pain, and significant increases in physical and social function scores. 12 out of 14 (85.7%) patients reported good to excellent satisfaction results at 6 months, and 12 out of 14 (85.7%) patients have had their expectations met from the procedure at 6 months follow up.

CONCLUSION

TOPAZ RF coblation is a good and effective method for the treatment of recalcitrant plantar fasciitis. Early results are encouraging, and we will continue to assess the patients over a longer follow-up period.

Eccentric loading, shock-wave treatment, or a wait-and-see policy for tendinopathy of the main body of tendo Achillis: a randomized controlled trial

BACKGROUND

Few randomized controlled trials compare different methods of management in chronic tendinopathy of the main body of tendo Achillis.

PURPOSE

To compare the effectiveness of 3 management strategies-group 1, eccentric loading; group 2, repetitive low-energy shock-wave therapy (SWT); and group 3, wait and see-in patients with chronic tendinopathy of the main body of tendo Achillis.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

Seventy-five patients with a chronic recalcitrant (>6 months) noninsertional Achilles tendinopathy were enrolled in a randomized controlled study. All patients had received unsuccessful management for >3 months, including at least (1) peritendinous local injections, (2) nonsteroidal anti-inflammatory drugs, and (3) physiotherapy. A computerized random-number generator was used to draw up an allocation schedule. Analysis was on intention-to-treat basis.

RESULTS

At 4 months from baseline, the Victorian Institute of Sport Assessment (VISA)-A score increased in all groups, from 51 to 76 points in group 1 (eccentric loading), from 50 to 70 points in group 2 (repetitive low-energy SWT), and from 48 to 55 points in group 3 (wait and see). Pain rating decreased in all groups, from 7 to 4 points in group 1, from 7 to 4 points in group 2, and from 8 to 6 points in group 3. Fifteen of 25 patients in group 1 (60%), 13 of 25 patients in group 2 (52%), and 6 of 25 patients in Group 3 (24%) reported a Likert scale of 1 or 2 points ("completely recovered" or "much improved"). For all outcome measures, groups 1 and 2 did not differ significantly. For all outcome measures, groups 1 and 2 showed significantly better results than group 3.

CONCLUSION

At 4-month follow-up, eccentric loading and low-energy SWT showed comparable results. The wait-and-see strategy was ineffective for the management of chronic recalcitrant tendinopathy of the main body of the Achilles tendon.

Immunohistochemical evaluation of substance P and calcitonin gene-related peptide in skin and periosteum after extracorporeal shock wave therapy and radial pressure wave therapy in sheep

OBJECTIVE

To evaluate the effect of focused extracorporeal shock wave therapy (ESWT) and radial pressure wave therapy (RPWT) on immunohistochemical staining for substance P and calcitonin gene-related peptide (CGRP) in the skin and periosteum of sheep.

ANIMALS

36 sheep.

PROCEDURES

All 4 limbs of 36 sheep were treated with ESWT, RPWT, or a sham treatment. For 14 days after treatment, at least 2 sheep were euthanized daily and tissue was harvested for histologic evaluation of nerves via staining for substance P and CGRP in the skin and periosteum.

RESULTS

No effects of ESWT or RPWT were observed on the number of nerves with stain uptake for substance P or CGRP in the skin or periosteum.

CONCLUSIONS AND CLINICAL RELEVANCE

Substance P- and CGRP-containing nerve fibers are not disrupted by EWST or RPWT. Further studies are needed to identify the mechanism of analgesia observed in association with these treatment modalities.

Force platform evaluation of lameness severity following extracorporeal shock wave therapy in horses with unilateral forelimb lameness

OBJECTIVE

To measure alterations in lameness severity that occur following use of extracorporeal shock wave therapy (ESWT) in horses with naturally occurring unilateral forelimb lameness.

DESIGN

Nonrandomized clinical trial.

ANIMALS

9 horses with unilateral forelimb lameness.

PROCEDURES

Force platform gait analysis was performed prior to administration of any treatments (baseline) and after use of local anesthesia to eliminate the lameness. Extracorporeal shock wave therapy was then administered, and gait analysis was repeated 8 hours later and then daily for 7 days.

RESULTS

Compared with the baseline value, peak vertical force was significantly increased 8 hours and 2 days after ESWT, and peak vertical force on day 2 was not significantly different from force measured after use of local anesthesia to eliminate the lameness. Similarly, vertical impulse was significantly increased, compared with the baseline value, 8 hours and 2 days after ESWT, but at all times, it was significantly lower than vertical impulse measured after use of local anesthesia.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that in horses with naturally occurring lameness, use of ESWT results in a period of acute improvement in lameness severity that typically persists for 2 days. Thus, in horses undergoing ESWT, exercise should be controlled for a minimum of 2 days after treatment to prevent further injury.

Second application of low-energy shock waves has a cumulative effect on free nerve endings

Some physicians recommend treating tendinopathies with multiple sessions of shock waves. Some evidence, however, suggests shock wave application can induce nerve fiber degeneration. We questioned whether repeated shock wave application provides a cumulative effect on nerve fibers compared with the effect of one application. One thousand shock wave impulses of an energy flux density of 0.08 mJ/mm were applied to the foot pad of 32 rats. After 14 days, 16 rats received a second application. The foot pads were resected on Days 7, 14, 28, and 42. Sections were processed immunohistochemically using antibodies for sensory nerve. We compared the number of epidermal nerve fibers in rats that received one application of shock waves with the fibers in rats that received two applications. During the first 4 weeks, there was nearly complete degeneration of epidermal nerve fibers in both groups. By the end of 6 weeks, reinnervation of the epidermis began in the single-treatment group. Reinnervation occurred slower in the repeated-treatment group. These data show that a second application has a cumulative effect on nerve fibers. Our data suggest multiple applications of low-energy shock waves might a provide longer-lasting antinociceptive effect.

Evaluation of skin sensitivity after shock wave treatment in horses

OBJECTIVE

To evaluate the effects of shock wave treatment on cutaneous nerve function, compared with the effects of local nerve block and sedation.

ANIMALS

18 clinically sound Swiss Warmbloods.

PROCEDURE

Horses were randomly allocated to 3 groups and received different amounts and types of shock waves (extracorporeal shock wave treatment [ESWT] or radial pressure wave treatment [RPWT]). Horses were sedated with xylazine and levomethadone. Shock waves were applied to the lateral palmar digital nerve at the level of the proximal sesamoid bones on 1 forelimb. Skin sensitivity was evaluated by means of an electrical stimulus at the coronary band before and 5 minutes after sedation and at 4, 24, and 48 hours after application of ESWT or RPWT. On the contralateral forelimb, skin sensitivity was tested before and 10 minutes after an abaxial sesamoid nerve block.

RESULTS

No significant changes in skin sensitivity were detected, regardless of the shock wave protocol applied. Mean reaction thresholds after sedation were more than twice the baseline thresholds. After the abaxial sesamoid block, no reaction was recorded in any of the horses.

CONCLUSIONS AND CLINICAL RELEVANCE

Application of ESWT or RPWT to the palmar digital nerve had no effect on cutaneous sensation distal to the treated region for at least 2 days after application. The analgesic effect of sedation on reaction to electrical stimuli was distinct but varied among horses.

Microtenotomy using a radiofrequency probe to treat lateral epicondylitis

PURPOSE

To evaluate the safety and effectiveness of microtenotomy using a radiofrequency (RF) probe to treat chronic tendinosis of the common extensor tendon origins of the elbow (lateral epicondyle).

TYPE OF STUDY

Prospective, nonrandomized consecutive case series.

METHODS

The average age of the 13 patients was 48.3 +/- 5.5 years. Before receiving the microtenotomy, all patients had tendinosis symptoms for 6 months or longer and had failed conservative treatment. The RF-based microdebridement was performed on the symptomatic tendon using the TOPAZ Microdebrider device (ArthroCare, Sunnyvale, CA). Patients were followed-up at regular postoperative intervals for 24 months. Pain status was documented using a visual analog scale self-reported measure. Functional outcome was assessed using the upper limb DASH evaluation and grip-strength measures. Quality of life assessment was evaluated using the SF-36 questionnaire. Magnetic resonance imaging was performed at regular intervals over the follow-up period.

RESULTS

Patients reported significantly reduced pain from baseline at the 7- to 10-day postoperative examination (P < or = .01). Pain reduction was statistically stable from 7 to 10 days through the 24-month postoperative period (P < or = .01). Limb-specific functional outcomes and quality of life scores were improved over baseline values. There were no perioperative or postoperative complications related to the procedure.

CONCLUSIONS

The RF-based microtenotomy procedure was safe and effective through at least 2 years. This procedure provides a valuable addition for treating patients with lateral epicondylitis associated with tendinosis who have failed conservative therapy.

LEVEL OF EVIDENCE

Level IV.

The effects of extracorporeal shock waves on the rat Achilles tendon: is there a critical dose for tissue injury?

INTRODUCTION

Extracorporeal shock waves (ESW) have been extensively studied in the field of orthopedics. Experimental and focused, well-designed clinical studies have suggested the clinical utilisation of ESW in several pathologies including delayed bone union, tennis elbow, and plantar fasciitis. However, the unwanted detrimental effects of ESW on various tissues have been questioned by some authors. In this experimental study, the effects of ESW were investigated at different intensity applications on the Achilles tendons of rat.

MATERIALS AND METHODS

A total of 32 adult Wistar albino rats was divided into four groups. The first three groups received 1000 impulses of 0.15 mJ/mm2, 1500 impulses of 0.15 mJ/mm2, and 2000 impulses of 0.20 mJ/mm2, respectively. The last group was kept as the control group. Subsequently, Achilles tendons were harvested for histological studies from all rats at the 3rd week after a single application of ESW.

RESULTS

There were no histological abnormalities observed in the Achilles tendons of the first two groups compared with the control group. No alteration in the histological configuration was observed, and consequently the pathologist who had been blinded could not differentiate these rats from the control group by light microscopy. However, in the high intensity group (2000 impulses of 0.20 mJ/mm2), grade II and III disorganisation of collagen fibers was noticed in 7 out of 8 rats, which was not detected in any of the rats from the first two groups (p<0.05). Consequently, the pathologist could distinguish the majority of the rats (7 out of 8) of this group from the remaining ones. Meanwhile, grade I lymphocyte infiltration was observed in some sections of the rats receiving the highest ESW dose.

CONCLUSION

This study confirms that ESW application at high intensity is associated with detrimental tissue effects. Additionally, it was suggested that the extent of tissue injury caused by ESW is dose-related.

Effectiveness of extracorporeal shock wave therapy in the treatment of previously untreated lateral epicondylitis: a randomized controlled trial

BACKGROUND

Extracorporeal shock wave therapy is a relatively new therapy used in the treatment of chronic tendon-related pain. Few randomized controlled trials have been performed on it, and no studies have examined the effectiveness of extracorporeal shock wave therapy as a frontline therapy for tendon-related pain.

HYPOTHESIS

Subjects treated with active extracorporeal shock wave therapy will have higher rates of treatment success than subjects treated with sham extracorporeal shock wave therapy.

DESIGN

Double-blind randomized controlled trial.

METHODS

Sixty subjects who had previously untreated lateral epicondylitis for less than 1 year and more than 3 weeks were included in this study. Subjects were randomly allocated to receive 1 session per week for 3 weeks of either sham or active extra-corporeal shock wave therapy. Subjects in the active therapy group received 2000 pulses (energy flux density, 0.03-0.17 mJ/mm(2)). All subjects were provided with a forearm-stretching program. After 8 weeks of therapy, subjects were classified as either treatment successes or treatment failures according to fulfillment of all 3 criteria: (1) at least a 50% reduction in the overall pain visual analog scale score, (2) a maximum allowable overall pain visual analog scale score of 4.0 cm, and (3) no use of pain medication for elbow pain for 2 weeks before the 8 week follow-up. Visual analog scale scores were also collected for pain at rest, during sleep, during activity, at its worst, and at its least, as well as for quality of life (using the EuroQoL questionnaire) and grip strength.

RESULTS

Success rates in the sham and active therapy groups were 31% and 39%, respectively. No significant difference was detected between groups (chi(2)(1)= 0.3880, P = .533). Mean change in quality of life over 8 weeks was an increase of 1.3 and 3.3 for sham and active therapy groups, respectively, and mean change in grip strength over 8 weeks was an increase of 7.4 kg and 6.8 kg for sham and active therapy groups, respectively.

CONCLUSIONS

Despite improvement in pain scores and pain-free maximum grip strength within groups, there does not appear to be a meaningful difference between treating lateral epicondylitis with extracorporeal shock wave therapy combined with forearm-stretching program and treating with forearm-stretching program alone, with respect to resolving pain within an 8-week period of commencing treatment.

Application of shock waves to rat skin decreases calcitonin gene-related peptide immunoreactivity in dorsal root ganglion neurons

There have been several reports on the use of extracorporeal shock waves in the treatment of pseudarthrosis, calcifying tendinitis, and tendinopathies of the elbow. However, the pathomechanism of pain relief has not been clarified. To investigate the analgesic properties of shock wave application, we analyzed changes in calcitonin gene-related peptide (CGRP)-immunoreactive (ir) dorsal root ganglion (DRG) neurons. In the nontreated group, fluorogold-labeled dorsal root ganglion neurons innervating the most middle foot pad of hind paw were distributed in the L4 and L5 dorsal root ganglia. Of these neurons, 61% were CGRP-ir. However, in the shock wave-treated group, the percentage of FG-labeled CGRP-ir DRG neurons decreased to 18%. These data show that relief of clinical pain after shock wave application may result from reduced CGRP expression in DRG neurons.