ISMST (International Society for Medical Shockwave Treatment)

Shockwave Literature

Comments by Dr Maria Cristina d’Agostino and Dr Kandiah Raveendran

A selection from the literature for the year 2017 – 2018 on the topic of “Shock Waves Medicine”.


In more recent years, SW Medicine got a rapid development, mainly due to a great improvement in basic science knowledge, thus confirming some already known and approved clinical applications, while opening the doors also for the future and sometimes still experimental applications as well.

The most important concept is the possibility, while applying a mechanical force, to induce some biological reactions (mechanotransduction), mainly based on controlling inflammation, in order to regulate and stimulate angiogenesis and tissue regeneration, or in any case to “reset” an altered local tissue turnover.

A better knowledge and comprehension of basic science mechanisms in SW Medicine (molecular reactions and pathways of SW mechanotransduction) are the prerequisite for optimizing clinical protocols and stimulating new reaserches and applications. Here a selection of some recent articles of high scientific level, showing to what extent research has progressed and which possible perspectives are open to us in the near future.     

Article 1  

Shockwaves prevent from heart failure after acute myocardial ischaemia via RNA/protein complexes.
Tepeköylü C1, Primessnig U2, Pölzl L1, Graber M1, Lobenwein D1, Nägele F1, Kirchmair E1, Pechriggl E3, Grimm M1, Holfeld J1.

1 Department for Cardiac Surgery, Medical University of Innsbruck, Innsbruck, Austria.
2 Department of Cardiology, Charité University Berlin, Berlin, Germany.

3 Division of Clinical and Functional Anatomy, Department of Anatomy, Histology and Embryology, Innsbruck
 Medical University, Innsbruck, Austria.

J Cell Mol Med. 2017 Apr;21(4):791-801. doi: 10.1111/jcmm.13021. Epub 2016 Dec 20.

Tepeköylü C and co-authors, already for many years committed to study cardio-regeneration inducted by SW and to clarify their mechanisms of action at the molecular level, only recently described how the regenerative effects of SWT may be mediated via RNA release and subsequent TLR3 activation. However, as extracellular self-RNA is rapidly degraded, in order to avoid an immunogenic response,  it remained unknown how extracellular RNA released upon SWT could escape from degradation. It is known that extracellular RNA mainly occurs in protein-complexed forms, and thus escapes degradation. Thereby, the cationic antimicrobial peptide LL37 has been described to be released upon mechanical stress, to form complexes with ribonucleic acids, to pass the cellular membrane and to subsequently activate intracellular. The Authors therefore hypothesized that SWT causes release of LL37. The peptide forms complexes with extracellular RNA, passes the cell membrane and activates TLR3.

In this study, they aimed to investigate whether:

(1) SWT in the acute setting of myocardial infarction prevents from the development of ischaemic heart failure; (2) SWT effects are indeed mediated via LL37/RNA complexes.

Myocardial infarction in mice was induced by ligation of the left anterior descending artery (LAD). SWT group animals received shock wave therapy directly after LAD ligation (300 impulses, delivered to the heart through the thorax, aiming at the ischaemic area, at an energy flux density of 0.38 mJ/mm2 at a frequency of 5 Hz, with an hand-held electohydraulic source designed for cardiac SW). At these energy levels, no adverse effects could be observed; Control group animals were left untreated.

Heart function was assessed 4 weeks later, via transthoracic echocardiography and pressure–volume measurements. The animals were killed 4 weeks after therapy for harvesting of the heart.

Moreover, the Authors performed cell culture and in vitro assays, to investigate the underlying mechanisms of SW-induced angiogenesis. For this purpose, human umbilical vein endothelial cells (HUVECs) were treated with SWT (250 impulses, at an energy flux density of 0.08 mJ/mm2 and a frequency of 3 Hz) and analyzed for proliferation (BrdU assay and Tube formation assay, recognized as specific for the assessment of angiogenesis) and protein expression (western blot for LL-37 antibody). Immunofluorescence staining was performed to analize proliferation and number of vessels; Masson–Goldner trichrome staining was performed for quantifying postinfarctional fibrosis. LL-37 ELISA kit was used to analyse LL37 release to the supernatant.

From a general point of view, four weeks after induction of myocardial infarction and subsequent shockwave treatment, transthoracic echocardiography showed significantly improved ejection fraction in treated animals, compared with the untreated control ones; this finding was confirmed also by haemodynamic pressure-volume measurement. Overall, diastolic and systolic function, as well as myocardial contractility showed improvement after SWT. From the histological point of view, in treated hearts there were significantly increased numbers of capillaries and arterioles, other than a significantly decreased amount of fibrosis.

Moreover, SWT enhanced proliferation rate in HUVECs, as well as increased segment formation, the number of junctions and nodes in a tube formation assay; all these effects could not be abolished by RNase treatment, but only with proteinase addition.

SW-treated cells showed significantly increased LL37 expression already 1 hour after SWT, compared to untreated controls; TLR3 activation was significantly increased after SWT as well. Also in this case the effect was not abolished upon RNase addition, but only with addition of proteinase.

Very interestinlgy, supernatant from cell cultures preconditioned with SWT showed similar effects on proliferation as the direct application of SWT to cells did, thus suggesting that in any case the final SWT effect/s had to be searched into the supernatant. TLR3 (that is activated by RNA) was increased after SWT; however, it remained unclear how the extracellular RNA could escape degradation and passed the cellular membrane to activate intracellular TLR3. Knowing that the fate of RNA is determined by RNA-binding proteins, the Authors hypothesized that released RNA binds to a protein and in this way can pass the cellular membrane. They applied SWT to a tube formation assay in the presence of RNase and proteinase and the results were very suggestive: RNase treatment did not abolish the SWT effect, but only additional treatment with proteinase did, thus demonstrating there was an RNA/protein complex.

Subsequently, in order to discover which protein could be responsible for the observed effects, they were able to observe an increased release and expression of the antimicrobial peptide LL37 after SWT. This protein is a key player in the development of psoriasis and is released upon mechanical stimulation; in turn, it binds nucleic acids and activates intracellular nucleic acid TLRs. At the moment, it is still unknown whether other proteins/ RNA complexes may also be involved.

Finally, for testing if TLR3 activation after SWT was indeed accomplished by protein/RNA complexes, the Authors performed a TLR3 reporter cell assay. SWT induced the activation of TLR3, and this effect could not be abolished by RNase treatment, but only with additional proteinase treatment, thus confirming that really RNA/protein complexes leaded to TLR3 activation after SWT.

Summarizing, the Authors showed for the first time that SWT after acute myocardial infarction can prevent from heart failure (left ventricular remodelling and cardiac dysfunction), via early induction of angiogenesis (increased number of capillaries and arterioles). In addition, they were able to go into the details of mechanotransduction, describing how the cellular response that results from SWT application is mediated via RNA/protein complexes, with involvement of the antimicrobial peptide LL37, activating TLR3.

Further studies in the near future are desirable, in order to further develop SWT as a potent therapeutic tool for the treatment of acute myocardial ischaemia and the prevention of ischaemic heart failure. Nevertheless, a better comprehension of the molecular mechanism of mechanotransduction may he helpful in optimizing protocols and clinical indications.

 

Article 2

Optimization of screw fixation in rat bone with extracorporeal shock waves.
Koolen MKE1, Kruyt MC1, Zadpoor AA2, Öner FC1, Weinans H1,2,3, van der Jagt OP4.
1 Department of Orthopaedics, University Medical Center Utrecht, UMC Utrecht, G.05.228, P.O. Box 85500,
  Utrecht 3508 GA, The Netherlands.
2 Faculty of Mechanical, Department of Biomechanical Engineering, Maritime, and Materials Engineering, Delft
  University of Technology, Delft, The Netherlands.
3 Department of Rheumatology and Clinical Immunology, University Medical Center Utrecht, Utrecht, the
  Netherlands.
4 Department of Orthopaedics, Elisabeth-TweeSteden Hospital, Tilburg, The Netherlands.

J Orthop Res. 2017 May 24. doi: 10.1002/jor.23615.

This experimental work may throw light about the possibility to apply SWT in combination with orthopedic surgery (osteosynthesis), especially in elderly people, affected by loss of bony mass. In fact, screw fixation in osteoporotic patients (mainly due to the increase of the median age) is becoming an increasing problem in traumatology, as rarefaction of cortical and cancellous bone threats biomechanical stability and metal implants (mainly screw) fixation. From the clinical point of view, this might result in delayed weight-bearing or failure of instrumentation.

The osteogenic effect of SWT is already well known and proven by many experimental (both in vivo and in vitro) and clinical studies; moreover, in clinical practice this therapy can now be considered as the gold standard for bone healing disorders, when a surgical intervention is not requested as a first choice of treatment. On the other hand, there are not enough data at the moment (and therefor not recommended), to apply SWT in an acute phase (as for expample a fresh fracture or soon after an osteosynthesis).

Nevertheless, based on the great number of basic science studies, confirming in any case the possibility to positively interact on local bone metabolism, the Authors hypothesized that the application of local peri-operative SWT could enhance osseointegration and subsequent screw fixation.

In an experimental model (eight female Wistar rats), they implanted two unicortical metaphyseal (cancellous) screw and two bicortical diaphyseal (bicortical) screws in each hind leg. The two cortical screws were implanted proximally in the femur, while the two cancellous ones in the distal femur and proximal tibia metaphyses respectively.

Immediately after implantation, one leg was treated with a total of 3000 unfocused extracorporeal shock waves (energy flux density 0.3 mJ/mm2 ) with an electrohydraulic source, while the other one served as non-treated internal control.

Evaluation of osseointegration was performed after 4 weeks with the use of microCT scanning, “pull-out tests” of the screws and histology with fluorochrome labeling. No adverse effects were reported in both treated and untreated legs.

After four weeks of follow - up, in the treated legs, an improved cortical screw fixation and consequently improved biomechanical properties were observed. The osteogenic reaction, in this experimental model was mostly detected at the periosteal interface, rather than at the bone – screw interface, where osteointegration is needed.
One explanation could be the direction of the applied pulses.

The same osteogenic effects were not observed for cancellous bone at 4 weeks; the Authors hypothesized that perhaps an earlier time point would have been more appropriate as at that time the cancellous bone response   might have already disappeared. De novo bone formation in the bone marrow was observed in some animals, but not close to the screws, thus not contributing to osteointegration.

Although some limitations described by the Authors (difference between screws, probably late time of observation, no knowledge about the best timing of SW application for positively interfering with osteointegration), nevertheless this study can be considered a prerequisite for further researches aimed to make shock wave therapy tailor-made for fracture fixation, with undoubted advantages in orthopedic surgery and traumatology, arising from a better and faster osteointegration, in term of recovery and rehabilitation, especially in elderly people.

 

Article 3  

Extracorporeal shockwave therapy as supplemental therapy for closure of large full thickness defects—Rat full-thickness skin graft model
Vlado Antonica, Bernd Hartmannb, Peter Balksc, Wolfgang Schadend, Christian Ottomannb
a Walter Reed Army Institute of Research, Department of Wound Infection, 503 Robert Grant Avenue, Silver
 Spring, MD, 20910, USA
b Unfallkrankenhaus Berlin, Zentrum für Schwerbrandverletzte mit Plastischer Chirurgie, Berlin, Germany
c Elisabeth Krankenhaus, Klinik für Anästhesie und Intensivmedizin, Leipzig, Germany
d AUVA-Trauma CenterMeidling, Vienna, Austria and Ludwig Boltzmann Institute for Experimental and Clinical  
  Traumatology and Austrian Cluster for Tissue Regeneration, Vienna, Austria

Wound Medicine 20 (2018) 1–6

Skin grafting (that is transplantation of skin or artificial dermal replacements) is a common and proven effective treatment in burn patients. As tissues are harvested from one anatomical location to a different place, ischemia is the major criteria for graft integration and healing. Based on the consideration of the increasing number of severe full-thickness skin injuries both in civilian and military settings to the burn injuries, the Authors underline the need for efficient, safe and cost-effective supplemental therapeutics, in order to optimize this surgical intervention, so reducing revision surgeries and related clinical risks and expenses, with undoubtful advantages  in the care management of this condition, both for the patients and health economy as well.

On the other hand, it is well known that the success of skin graft integration and viability is highly related to the revascularization, suppression of over-exuberant inflammation and control of infection, and these biological assumptions may be the key for the best therapeutic solution.

In more recent years Extracorporeal Shock Wave Therapy (ESWT) has turned out to be a non – invasive, safe, effective and low risk medical procedure in the field of Regenerative Medicine, due to its beneficial effects in increasing tissue perfusion (angiogenesis and lymphoangiogenesis), while decreasing inflammation. Although already published some interesting results for the use of ESWT in skin flaps, still limited data are available on the efficacy of the ESWT on the full thickness grafts and on the effects of repetitive ESWT applications for healing and graft survival. For these reasons, the Authors investigated the effects of ESWT on full thickness grafts in an animal model, in order to shed light on the beneficial effects of ESWT and its potential use in clinical pratice for these conditions.

A total of 30 female Wistar rats (300–400 gr) were used in this study. All animals underwent surgical procedure consisting in abdominal fullthickness skin grafts; 10 animals were assigned into Controls, ESWT-1 (one treatment, day 0) and ESWT-2 (repeated, days 0 and 4 after surgery) respectively. Animals that were assigned to receive ESWT were treated immediately after the surgical procedure, and those ones assigned to receive two treatments, received a second application at day 4 after surgery. All rats of ESWT-1 and ESWT-2 groups were treated with shockwaves at Energy Flux Density (EDF) 0.1 mJ/mm2 and a total of 300 impulses across the entire region of the graft, by using an electrohydraulic source (defocused applicator).

Full-thickness biopsies were collected on days 4, 6, 9 and 12 after the surgery.

Results were assessed by morphological (digital images were acquired, measured and analized) and histological evaluation (punch biopsies) of skin grafts (time-to-heal, skin graft thickness, number of capillaries and level of inflammation).

Macroscopic evaluation showed similar healing rate (primary end – point of the study) in all the three groups, nevertheless, microscopic evaluation showed some interesting details, here briefly summarized.

Both single and repeated ESWT were able to induce beneficial effects on skin grafts, although a similar healing rate between treated and non-treated grafts was observed. Repeated ESWT applications seemed to exert its beneficial effects at earlier time points and to a higher extent than single application. Moreover, the repeated ESWT induced an increased number of capillaries and thickness in the dermal layer, earlier than single treatment. Inflammatory cell infiltration was increased after ESWT treatment, but this did not induce a negative effects on the wound healing.

In spite of some still open questions (mainly which is be the best treatment schedule for obtaining full epithelialization and strongest angiogenesis), these data suggest that repeated treatments increase effectiveness of ESWT and encourage further investigations about number and dynamic of applications.

Based on the literature and the results of this animal study, it is possible to conclude, in agreement with the Authors, that Extracorporeal Shock Wave Therapy can be considered as an emerging and promising new modality for tissue regeneration, now as supplemental treatment in full thickness skin graft as well. Its characteristics of non-invasiveness, absence of relevant side effects and negative interactions with drugs, together with cost effectiveness and comparable efficacy to existing treatments make of ESWT an unique and versatile therapeutic tool in the field of Regenerative Medicine.


Article 4

Complications of extracorporeal shockwave therapy in plantar fasciitis: Systematic review

Roerdink RLDietvorst Mvan der Zwaard Bvan der Worp HZwerver J


Int J Surg. 2017 Oct; 46:133-145. doi: 10.1016/j.ijsu.2017.08.587. Epub  2017 Sep 7.


BACKGROUND: 

Extracorporeal shockwave therapy (ESWT) seems to be an effective treatment for plantar fasciitis (PF) and is assumed to be safe. No systematic reviews have been published that specifically studied the complications and side effects of ESWT in treating PF. Aim of this systematic review is therefore to evaluate the complications and side effects of ESWT in order to determine whether ESWT is a safe treatment for PF.

METHODS: 

For this systematic review the databases PubMed, MEDLINE, Cochrane and Embase were used to search for relevant literature between 1 January 2005 and 1 January 2017. PRISMA guidelines were followed.

RESULTS: 

Thirty-nine studies were included for this review, representing 2493 patients (2697 heels) who received between 6424 and 6497 ESWT treatment sessions, with an energy flux density between 0.01 mJ/mm2 and 0.64 mJ/mm2 and a frequency of 1000-3800 SWs. Average follow-up was 14.7 months (range: 24 h - 6 years). Two complications occurred: precordial pain and a superficial skin infection after regional anaesthesia. Accordingly, 225 patients reported pain during treatment and 247 reported transient red skin after treatment. Transient pain after treatment, dysesthesia, swelling, ecchymosis and/or petechiae, severe headache, bruising and a throbbing sensation were also reported.

CONCLUSION: 

ESWT is likely a safe treatment for PF. No complications are expected at one-year follow-up. However, according to the current literature long-term complications are unknown. Better descriptions of treatment protocols, patient characteristics and registration of complications and side effects, especially pain during treatment, are recommended.

COMMENT

Although complications of shockwave treatment are rare, this metaanalysis is an important study to show that there are complications albeit very rare. Pain during treatment is part of the treatment and probably not categorized as a complication. We should try to find ways to reduce this treatment pain.


Article 5

The Role of Extracorporeal Shockwave Treatment in Musculoskeletal Disorders


Moya Daniel, MD; Ramón Silvia, MD, PhD; Schaden Wolfgang, MD; Wang Ching-jen, MD; Guiloff Leonardo, MD; Cheng Jai-hong, MD;

The Journal Of Bone And Joint Surgery - Current Concepts Review: 7 February 2018 - Volume 100 - Issue 3 - p. 251-263


Increasing evidence suggests that extracorporeal shockwave treatment (ESWT) is safe and effective for treating several musculoskeletal disorders.


Two types of technical principles are usually included in ESWT: focused ESWT (F-ESWT) and radial pressure waves (RPW). These 2 technologies differ with respect to their generation devices, physical characteristics, and mechanism of action but share several indications.


Strong evidence supports the use of ESWT in calcifying tendinopathy of the shoulder and plantar fasciitis.


The best evidence for the use of ESWT was obtained with low to medium energy levels for tendon disorders as well as with a high energy level for tendon calcification and bone pathologies in a comprehensive rehabilitation framework.

COMMENT

 

This is a current concepts review and emphasizes the important role that shockwave treatment plays in the treatment of musculoskeletal disorders. This is our strongest forte and the one used the most throughout the world. It is appropriate that the JBJS has published this, to inform orthopaedic surgeons of this simple and effective treatment modality for many tendinopathies and bony nonunions. We hope that this article will lead to greater awarenwss amongst the orthopaedic community.