Radial shockwave has direct and indirect effects on various structures (cells and hence tissues) throughout the body. Some of these effects are positive and some negative. There are many claims for the micro or cellular effects of shockwave.
These micro structural or cellular effects often culminate together to have macro effects on actual parts of the body. These are generally referred to as the tissue effects of shockwave.
Tendinopathy (insertional and mid substance):
Common Conditions: Achilles tendinopathy, Patella tendinopathy (jumpers knee), Quadriceps tendonitis, Lateral/medial epicondylitis (tennis and golfers elbow), Rotator cuff tendinopathy, Hand tendons (De Quervains etc.), Hamstring tendonitis, Tibialis anterior/peronei tendonitis (shin splints), Foot tendons, Bicep/triceps tendonitis.
Who has studied it
There are lots of studies investigating the effects of shockwave therapy on tendinopathies. Wang (2012) reviewed the studies in shockwave and tendinopthies in great detail. Shockwave has been used primarily to treat chronic tendinopathy, which is an overuse syndrome categorised by pain/tenderness due to mucoid and chondroid degeneration, formation of plump tenocytes, increased fibroblastic and myofibroblastic cells and absent inflammatory cells (Wang et al., 2007). Rompe et al (1998) demonstrated the effects of shockwave on the achilles tendon (in rabbits), and suggested that low energy flux density of less than 0.28 mJ/mm2 should not be used clinically. In their study, a statistically significant increase of capillary formation was found with higher energy shock wave (0.60 mJ/mm2), which also caused more tissue reaction and potential damage to the tendon tissue. However this effect, listed as negative by Rompe et al (1998), has been shown by Wang, Huang & Pai (2002) to be a positive factor! Wang, Huang & Pai et al (2002) demonstrated that shockwaves enhance neovascularization with formation of new capillary and muscularised vessels at the tendon-bone junction of the achilles tendons in dogs. In another study, Wang et al (2003) found that shockwave therapy induces the ingrowth of neo-vessels (neovascularization) including capillary and muscularised vessels at the tendon-bone junction. As this effect often lasts over 12 weeks it is more likely this has an impact on the problem rather than the growth/proliferating factors which peak early but then return to normal levels by 8 weeks. Several studies have reported that chronic painful tendinopathies have increased numbers of sprouting non-vascular sensory, substance P-positive nerve fibers and decreased occurrence of vascular sympathetic nerve fibers. It is suggested that the altered sensory-sympathetic innervation may play a role in the pathogenesis of tendinopathy (Lian et al., 2006).
Tendinopathy has been studied in some depth and due to the diversity of the pathologies, histologies and logistics of recovery it is normal to look at different tendinopathy studies in relation to each other rather than between sites.
It has been demonstrated that high-energy shock waves from 0.42 to 0.54 mJ·mm2 can induce tendon lesion. Thus it is recommended not to use shock waves with energy flux densities of over 0.28 mJ·mm2 in the treatment of tendinopathies. Local complications reported are usually not serious: soft tissue swelling, cutaneous erosions, haematoma, local pain (Mouzopoulos et al., 2007).
Lateral epicondylitis of the elbow has been the center of a lot of studies. Success rates range from 68% to 91% (Furia, 2005, Ko, Chen & Chen, 2001, Ozturan et al., 2010, Radwan et al., 2008, Rompe et al., 2004, Rompe et al., 1997, Spacca, Necozione & Cacchio, 2005). Rompe et al (1996) reported good or excellent outcomes in 48% and an acceptable result in 42% (at 24 weeks) in patients with chronic tennis elbow. Wang & Chen (2002) in a longer study (12 to 26 months) reported 61.4% were pain free, 29.5% were significantly better, 6.8% were slightly better and 2.3% were unchanged.
Few studies have reported no effect of ESWT or less effect compared to placebo (Buchcinder et al, 2005, Haake et al., 2002, Haake et al, 2002, Melikyan et al., 2003, Speed et al., 2002, Staples et al., 2008). In a review of 9 placebo-controlled trials, Buchbinder et al (2005) concluded that there is little or no benefit in terms of pain and function in lateral elbow pain, whilst there was some evidence that steroid injection may be more effective than ESWT (Buchbinder et al, 2006, Buchbinder et al, 2005). Haake et al (2002) in a review of 20 studies concluded that no clinically relevant efficacy has been proven for the use of ESWT for lateral elbow pain. Speed et al (double blind randomized trial) concluded that there appears to be a significant placebo effect of moderate dose ESWT in subjects with lateral epicondylitis, but there is no evidence of added benefit of treatment when compared to sham therapy (Haake et al, 2002). So why the differences? The differences can be attributed to patient selection, the application techniques, the type of devices, and the method of outcome measurements, according to Wang (2012). Despite the controversy in the studies shockwave offers a treatment option that has been shown to be effective in the bulk of the studies. With limited side effects, in chronic patients what is the worst that can happen? They don’t improve! They weren’t improving anyway!!!
Jumper’s knee, or medically patella tendinopathy, has had quite a bit of scrutiny in the literature. Success rates range from 73.5% to 87.5% (van Leeuwen et al, 2009, Vulpiani et al, 2007, Wang et al, 2007, Zwerver et al, 2010, Hsu et al, 2004, Peers et al, 2003). Shockwave has also been used in patella tendinopathy secondary to harvesting of the patella tendon for ACL reconstruction. Wang et al (2007) followed patients after shockwave for 2-3 years and showed 43% excellent outcome, 47% good, 10% fair and none poor for the study group, and none excellent, 50% good, 25% fair and 25% poor for the control group. Ultrasonographic examination showed a significant increase in the vascularity of the patella tendon and a trend of reduction in the patella tendon thickness after ESWT as compared to conservative treatments (Wang et al, 2007). Peers et al (2003) compared surgically treated knees with shockwave treated knees, and reported a comparable functional outcome in patients with patella tendinopathy resistant to conservative treatments. It appears that ESWT is effective in the management of patients with chronic patella tendinopathy.
Many studies have investigated the effect of ESWT in Achilles tendinopathy, and most reported favorable results with success rates similar to patella tendinopathy (Rasmussen et al, 2008, Furia, 2008, Rompe et al, 2008, Furia, 2006, Furia, 2005). Rompe et al, 2007, Rompe et al, 2008, Rompe et al, 2009, Costa et al, 2005 and Rasmussen et al, 2008 evaluated the efficacy of shockwave on Achilles tendinopathy. Evidence from meta-analysis of data from two studies comparing shockwave to eccentric exercise (Rompe et al, 2007, Rompe et al, 2008) found no significant effects for outcomes of pain and function at 16 weeks. One of these studied Insertional AT (Rompe et al, 2008) while the other studied midportion AT (Rompe et al, 2007). A further study by Rompe and colleagues (2009) examined the effects of SWT when added to eccentric exercise, with effect sizes showing moderate significant effects favouring combined SWT and eccentric exercise over eccentric exercise alone after 16 weeks. The 2007 study by Rompe et al. also included a wait-and-see group, allowing comparisons to be made between SWT and a no-treatment control. Moderate significant effects were found that favour SWT at 16 weeks. Two studies (Costa et al, 2005 and Rasmussen et al, 2008) evaluated SWT using double-blind, placebo-controlled study designs. Costa et al. (2005) compared SWT to sham SWT over 12 weeks. There were no significant pain effects favouring either SWT or sham SWT at 12 week follow-up. Although participants were followed up at 12 months, insufficient data was available to calculate effect sizes. Rasmussen et al. (2008) investigated differences between SWT and sham SWT as an addition to a conservative therapy programme that included eccentric exercise. After four weeks of intervention, no significant effects were found for either group. Again there was insufficient data to evaluate longer follow up periods. Sussmilch-Leitch et al (2012) said shockwave appears more efficacious than no treatment (agreeing with Rompe et al, 2007), but suggested a placebo effect associated with pain and function outcomes. But they did recommend shockwave be used in conjunction with eccentric exercise at the Achilles tendon because together patients had better outcomes (Rompe et al, 2009).
Anatomical effects
Shockwave improves the angiogenetic growth factors, which in turn induce neovascularization and improve blood supply at the tendon-bone junction of the Achilles tendon (Rasmussen et al, 2008). Increases of PCNA and neo-vessels begin in 1 week and persist for 12 weeks and longer. Shockwave therapy alleviates pain due to Insertional tendinopathy by the induction of neovascularization and improvement of blood supply to the tissue, and initiating repair of the chronically inflamed tissues by tissue regeneration.
Biological effects
Wang et al (2003) have shown that shockwave therapy releases angiogenetic growth and proliferating factors including eNOS, VEGF, and PCNA. The eNOS and VEGF began to rise as early as one weekend, remained high for 8 weeks, then declined to baseline in 12 weeks.
Dosage
Treatment density from 0.12mj/mm2 up to 0.51mj/mm2 have been used in the literature. 2000 impulses, for 3 sessions once per week seems to be the standard used. 3 sessions once per week.
Muscle (muscle, myofascia & trigger points):
Common Conditions: Trapezius trigger points, Rotator cuff, Piriformis syndrome, Ilio tibial band syndrome (ITB syndrome), Gluteal pain, Hamstrings, Calves (gastrocnemius/ peronei/tibialis anterior), Quadriceps, Common wrist flexors/extensors.
Who has studied it
Muscle treatment with shock waves (focused) was first seen in the 1990s (Kraus et al, 1999, Lohse-Busch et al, 1997). It was used as an alternative to manual trigger point treatment. The results of these treatments was reduction in pain, lower muscle tone and decreased muscle shortening. Shockwave moved into the treatment of myofascial syndromes in the 2000s. Initially, radial shock waves (r-ESWT) were used for myofascial problems (Bauermeister, 2003, Gleitz, 2003), but focused shock waves followed (Bauermeister, 2005, Bauermeister, 2007, Gleitz et al, 2006, Muller-Ehrenberg, 2005).
Shockwave has been shown to be effective in muscular treatments through various mechanisms. Studies have shown separation of fixed actin-myosin links by the input of mechanical energy (spalling) as long as the force is perpendicular to the muscle fibre direction (Shah et al, 2008, Travell & Simons, 1983). Circulatory effects e.g. improvement of blood circulation through reactive hyperemia and angiogenesis (Shah et al, 2008, Kuo et al, 2009, Wang, 2003) and dilution of vasoneuroactive substances as a result of reactive hyperemia (Shah et al, 2008, Mense & Simons, 2001). Improvements in pain through pain modulation by the release of substance P (Hausdorf et al, 2008, Maier et al, 2003) and CGRP (Takahashi et al, 2003), release and synthesis of nitric oxide (Mariotto et al, 2009, Neuland, Duchstein & Mei, 2004), selective degeneration of C-fibres (Hausdorf et al, 2008), pain gate control theory (Gregor & Zimmerman, 1972, Wall & Cronly-Dillon, 1960). Reduction in muscle tone through biological mechanotransduction (Ingber, 2006, Jaalouk & Lammerding, 2009, Neuland, Duchstein & Mei, 2004).
Trigger point treatment can be separated into two areas: to alleviate pain and to permanently eliminate the trigger point complex. Shockwave trigger point therapy uses the concept of mechanical energy separating the fixed actin-myosin links (Travel & Simons, 1983), breaking of contraction ‘knots’ (Mense & Simons, 2001), improvement in local blood circulation through reactive hyperemia and resolution of the ischaemia-induced energy crisis (Sikdar et al, 2010), reduced concentration of vasoneuroactive substances (Shah et al, 2008) as well as muscle relaxation.
Anatomical effects
Shockwave can mechanically influence muscles. The physiological intrinsic oscillations of 15 to 30 Hz have been described by Nazarov & Gorozhani (1988) as important for muscular relaxation, blood circulation and lymphatic drainage. Breaking actin-myosin Links (Travell & Simons, 1983, Shah et al., 2008) and destruction of damaged fibers (Mense & Simons, 2001b). Shockwave can influence pain at both the neural and biological levels. They do this through improved blood flow (Zimmermann et al., 2009, Frairia & Berta, 2011), reducing muscle tension/stiffness (Zimmermann et al., 2009), reduction of pain through various mechanisms (Jeon et al. 2012) and generation of action potentials (Schelling et al. 1994).
Biological effects
Substance P is concentrated in unmyelinated C-fibres and lightly myelinated A-nerve fibres. It is released at central and peripheral terminals of sensory nociceptive neurons after shockwave (Gerdesmeyer & Weil, 2007, Gerdesmeyer et al, 2003, Gleitz, 2003). CGRP is a marker of sensory neurons typically involved with pain perception and goes hand in hand with substance P (Gleitz, 2011). Activation of peripheral sensory neurons by local depolarization releases substance P and CGRP. Both substances then act on target cells such as mast cells, immune cells and vascular smooth muscle cells, thus producing inflammation.
Dosage
There are two methods used both individually and combined to treat muscles dependent on the prevailing problems. Pressures (radial shock waves) vary between 1.6 (90mj) and 4 bar (240mj), depending on where the pain is and the size of the shockwave head i.e. smaller head = use lower pressure, bigger head = use higher pressure. Heads with a small surface (6mm) should be used with extreme caution due to the high peak pressures. Shockwave frequency is from 4 to 15 Hz (15 Hz frequency is generally perceived as causing less pain). Anywhere from 200-4000 shocks is used (see below).
Isolated trigger points: The trigger point or points are treated locally with a small head (6mm or 15mm) for 200 to 1000 shocks (don’t push the head down into the point). This is done per trigger point i.e. more points = less shocks per point, less points = more shocks per point.
General muscle tightness or myofascial pain: Muscle smoothing with a large head (20mm plus), applying 3000 to 4000 radial shock waves at 15hz or above. Now you can press in to the muscle!
Combined: Use of focused Shockwaves in trigger point therapy The trigger points are first treated locally, applying 200 to 400 focused shock waves. Then followed with muscle smoothing with up to 4000 shocks at a frequency of 15 Hz, in accordance with the stretch-and-spray technique developed by Travell and Simons (1992).
Treatment frequency: Weekly treatments until the problem resolves.
Bone spur (osteophyte):
Common conditions: Bony heel spur (inferior/posterior calcaneal), Haglunds deformity, Elbow spur, Ankle joint line, Toes, Fingers
Who has studied it
Rompe, Schoellner & Nafe (2002) showed a satisfying clinical outcome after application of low energy extracorporeal shock waves in patients with plantar fasciitis and a heel spur. Similar positive outcomes have been shown in various other studies (Krischek et al., 1998, Maier et al., 2000, Perlick, Boxberg & Giebel, 1998). Maier et al. (2000) reported good or excellent results in heels at twenty-nine months after treatment. Wang et al. (2000) reported that 80% of their patients were either free of symptoms or substantially better at twelve weeks after shockwave therapy. Ogden et al. (2001) performed a randomized, placebo-controlled study. Twelve weeks after application of Shockwaves, 47% of the patients had improved (however 30% of the placebo group did too). This led to the United States Food and Drug Administration approving shockwave therapy for painful heels. Buch et al. (2001) reported the results of another randomized, placebo-controlled study (again for the United States Food and Drug Administration). At three month follow up, 70% of the patients in the treatment group and 40% of those in the placebo group had reported good recovery (particularly in relation to morning pain). Chen et al. (2001) showed at six months post treatment, 59% of patients had no symptoms and 27% had substantial improvement. Rompe et al (2002) also found six months after low-energy shockwave treatment, the results of three applications of 1000 impulses were significantly better than those of three applications of ten impulses (57% good or excellent outcomes compared with 10% good or excellent outcomes). At five years after the shockwave therapy, only 13% of the patients in the real shockwave group had proceeded to surgery compared to 58% of the patients in the sham group. Rompe et al (2002) went on to say that “if even more patients in this group had undergone surgery, the ratings concerning pain and walking may have reached levels comparable with those in Group I”. Or in other words shockwave showed results in patient scores comparable to if not better than surgery.
Anatomical effects
Shockwave can eliminate spurs through spalling/spall cracks, cavitation and tensioning.
Biological effects
Direct effect only
Dosage
Rompe et al. (2002) recommended 0.08mj/mm2 for 1000 shocks every 7 days for 3 sessions
Calcific Tendonitis:
Common Conditions: Achilles tendon, Rotator cuff, Medial/lateral epicondyles, Patella tendon, Quads Tendon, Bicep tendon, Triceps tendon, Peroneal tendon.
Who has studied it
Most studies on calcific tendonitis have been done in the shoulder. Success rates of shockwave therapy in patients with calcific tendinitis of the shoulder are reported ranging from 78% to 91% (Cacchio et al, 2006, Daecke, Kusnierczak & Loew, 2002, Hsu et al, 2008, Jakobeit et al, 2002, Krasny et al, 2005, Pan et al, 2003, Peters et al, 2004, Pleiner et al, 2004, Rompe et al, 1998, Wang, Ko & Chen, 2001). Consentino et al (2003) found that calcification was resolved in 31% of their cases with a further 40% having at least partial re-absorption (as seen on x-ray). These improvements followed into reduced pain, better range of motion, and increased function. Spindler et al (1998) reported complete pain relief and full shoulder joint movement in three patients two years after shockwave therapy, and a fragmentation of calcification was achieved in only a day. Wang et al (2003) compared the results of shockwave therapy with a control group. At 2 to 3 year follow-up, the overall results of the shockwave group were complaint free in 60.6%, significantly better in 30.3%, slightly better in 3.0% and unchanged in 6.1%. Only 6% showed recurrent pain of lesser intensity, and none showed worse symptoms. The control group results reported slightly better in 16.7% and unchanged in 83.3%. Radiographs showed complete elimination of calcium deposits in 57.6%, partial elimination or fragmentation in 15.1%, and unchanged in 27.3% for the shockwave group. No one showed recurrence of calcium deposits 2 years after shockwave therapy. There is a correlation of functional improvement with the elimination of calcium deposit (Wang et al, 2003). Jurgowski et al (1993) treated patients with two sessions of 2,000 impulses each of shockwave and reported a marked reduction of symptoms with an average of 30% improvement in the Constant score at the 12 week follow-up. Radiographs showed complete elimination of the calcification in over 60% of the patients, and partial elimination in the rest. Magnetic resonance imaging did not show any lasting damage to bone or soft tissue (Jurgowski et al, 1993, Loew et al, 2000). Rompe et al (1997) reported significant improvement in 72.5% of the patients and only 15% of the patients treated reported no improvement. Complete or partial disintegration of the calcium deposits was observed in 62.5% of the patients. In another study, Rompe, Zoellner & Nafe (2001) reported that shockwave therapy provides equal or better results than surgery in patients with calcifying tendonitis of the shoulder.
Anatomical effects
Shockwave can eliminate calcification through spalling/spall cracks, cavitation and tensioning.
Biological effects
Direct effect only
Dosage
Cosentino et al. (2003) recommended 0.28mj/mm2 for 1200 shocks every 4-7 days (they continued until calcification had gone on x-ray)
Fasciitis:
Common Conditions: Plantar fasciitis
Who has studied it
Plantar fasciitis has been extensively studied with a reported success rate from 34% to 88% (Buch et al, 2002, Chen, Chen & Huang, 2001, Chuckpaiwong, Berkson & Theodore, 2009, Gerdesmeyer et al, 2008, Gollwitzer et al, 2007, Hammer et al, 2003, Hyer, Vancourt & Block, 2005, Ibrahim et al, 2010, Kudo et al, 2006, Metzner, Dohnalek & Aigner, 2010, Norris, Eickmeier & Werber, 2005, Ogden et al, 2004, Rajkumar & Schmitgen, 2002, Rompe et al, 2003, Rompe, Schoellner & Nafe, 2002, Wabg et al, 2000, Wang, Chen & Huang, 2002, Wang et al, 2006, Weil et al, 2002). The majority of the published papers report a positive and beneficial effect. Rompe, Schoellner & Nafe (2002) have shown that shockwave is an effective therapy for plantar fasciitis with significant alleviation of pain and improvement in function. Wang, Chen & Huang (2002) showed at one year follow-up the overall results were 75.3% complaint free, 18.8% significantly better, 5.9% slightly better and none unchanged or worse. The recurrence rate was 5%. They concluded that shockwave therapy is a safe and effective modality in the treatment of proximal plantar fasciitis.
In contrast, few studies reported the opposite results of ESWT in the treatment of plantar fasciitis (Buchbinder et al, 2006, Buchbinder et al, 2002, Speed et al, 2003, Greve et al, 2009, Haake et al, 2003). Buchbinder et al (2002) said there was no evidence to support a beneficial effect of shockwave over placebo (on pain, function and quality of life). Haake et al (2003) compared shockwave to placebo and the results showed that shockwave was ineffective in the treatment of chronic plantar fasciitis. In a randomised double blind control trial, Speed et al (2003) found no treatment effect of moderate dose shockwave in subjects with plantar fasciitis. Efficacy may be highly dependent upon machine types and treatment protocol (Speed et al, 2003). Therefore, controversy exists on the effect of ESWT in the treatment of chronic plantar fasciitis. Wang (2012) said the differences are probably due to the methodology, patient selection criteria, use of different devices, different energy levels/total energy and the outcome measurements.
Several studies have compared the effects of shockwave with surgery, local corticosteroid injection or physical (physio) therapy in the treatment of proximal plantar fasciitis (Weil et al, 2002, Othman & Ragab, 2010, Yucel et al, 2010). Comparison of surgical treatment (plantar fasciotomy) and shockwave showed comparable functional outcomes (Weil et al, 2002). Physical (physio) therapy has shown to be comparable to or even better than shockwave in proximal plantar fasciitis, however, no one has yet to study them combined (Greve, Grecco & Santos-Silva, 2009). Corticosteroid injection shows better short-term effects, but the long-term results favor shockwave (Yucel et al, 2010).
The application of ESWT in proximal plantar fasciitis is performed with either local anesthesia or no anesthesia. Several reports showed that ESWT is less effective when the treatment is performed with the use of local anesthesia (Labek et al, 2005, Rompe et al, 2005).
Wang (2012) said in summary, the literature review reveals discrepancy and controversy on the effect of shockwave for plantar fasciitis. Many factors can influence the effects of shockwave in the treatment of plantar fasciitis. The vast majority of the published papers are in favor of ESWT. Additional studies are needed to validate the effectiveness of ESWT in the treatment of plantar fasciitis.
Anatomical effects
Shockwave can eliminate calcification whilst also improving the angiogenetic growth factors, which in turn induce neovascularization and improve blood supply at the fascial-bone junction. Shockwave therapy alleviates pain due to Insertional tendinopathy by the induction of neovascularization and improvement of blood supply to the tissue, and initiating repairs of the chronically inflamed tissues by tissue regeneration.
Biological effects
Wang et al (2003) have shown that shockwave therapy releases angiogenetic growth and proliferating factors including eNOS, VEGF, and PCNA. The eNOS and VEGF began to rise in as early as one weekend, remained high for 8 weeks, then declined to baseline in 12 weeks
Dosage
Rompe, Schoellner & Nafe (2002) suggested that three weekly treatments with 1,000 impulses of low-energy shockwave at 0.06 mJ/mm2 appear to be an effective therapy for plantar fasciitis with significant alleviation of pain and improvement in function.
Bone Healing (acute):
Common conditions: Fracture or broken bone.
Who has studied it?
Many studies have investigated the effects of shockwave therapy on fracture healing. Haupt et al. (1992) found a positive effect of shockwave treatment on fracture healing in rats. Johannes et al. (1994) even showed the promotion of bony union with shockwave therapy in hypertrophic non-unions in dogs. Wang et a.l (2001) demonstrated that shock wave therapy enhanced callus formation and induced cortical bone formation in acute fractures in dogs. But not all of the studies have been positive. Forriol et al. (1994) said that certain types of shockwave treatment (dosage dependent) might delay bone healing. Remember shockwave at alternative levels starts to destroy bone not heal it.
Anatomical effects
Wang et al. (2001) have demonstrated that shockwave therapy produces a significantly higher bone mass including bone mineral density, callus size, ash and calcium contents, and better bone strength.
Biological effects
The main effect of shockwave on bone healing is most certainly the activation of osteoblasts through integrin activation (Rubin, Rubin & Jacobs, 2006) and differentiation of mesenchymal stem cells (Chen et al., 2004).
In an excellent review article on this subject Wang (2012) said shockwave also has an influence on superoxide which mediates induction of ERK-dependent osteogenic transcription factor (CBFA-1) and mesenchymal cell differentiation toward osteoprogenitors (Wang et al., 2002). Extracorporeal shockwave promotes bone marrow stromal cell growth and differentiation toward osteo-progenitors associated with TGF-b1 and VEGF induction (Wang et al., 2002). Physical shockwave mediates membrane hyperpolarization and ras activation for osteogenesis in human bone marrow stromal cells (Wang et al., 2001). Shockwave promotes bone regeneration by the recruitment of mesenchymal stem cells and expressions of TGF-b1 and VEGF (Chen et al., 2004).
Dosage
The effects of shockwave therapy on bone mass and bone strength appear to be both dose dependent and time related (Wang et al., 2004).
Acute fracture healing: Shock wave treatment at 0.47 mJ/mm2 energy flux density with 4000 impulses showed much better results than treatment at 0.18 mJ/mm2 energy flux density with 2000 impulses (Wang et al., 2004).
Bone Healing (non-union):
Common conditions: Humerus, Tibia, Femur, Fibula, Metatarsal, Metacarpals, Tarsals, Carpals, Radius, Ulna
Who has studied it?
Many studies investigated the effect of shockwave therapy for non-union and delayed union of long bone fractures. Success rates of achieving bony union range from 50% to 85% (Cacchio et al., 2009, Elster et al., 2010, Wang et al., 2001, Haupt, 1997, Schaden, Fischer & Sailer, 2001, Valchanou & Michailow, 1991, Vogel et al, 1997, Rompe et al, 2001, Schleberger & Senge, 1992). Schaden, Fischer & Sailer (2001) reported a success of 85% in the treatment of 115 delayed and non-unions. Valchanou & Michailow (1991) reported bony unions in 70 of 82 patients with delayed or chronic non-union of fractures. Vogel et al (1997) reported a 60.4% union rate in 48 patients with pseudarthroses. Wang et al (2001) treated 72 patients with non-unions of long bone fracture with shockwave therapy, and reported a success rate of 82.4% bony union at 6 months. Rompe et al (2001) reported a 50% success rate (clinical study), whereas Schleberger & Senge (1992) showed successful fracture healing in three of four pseudoarthroses treated with 2000 impulses of shockwaves. Recently, Elster et al (2010) reported an 80.2% success in 172 non-union of the tibia. The results of ESWT in non-union of long bone suggest that shockwave is comparable to surgical intervention.
Anatomical effects
Cacchio et al. (2009) have shown a change in levels of Osteocalcin (OC) and bone specific alkaline phosphatase (bALP) following each session of shockwave therapy.
The changes in the bone are most likely the same as for acute bone healing. Wang et al (2002) have demonstrated that shockwave therapy produces a significantly higher bone mass including bone mineral density, callus size, ash and calcium contents, and better bone strength.
Biological effects
The main effect of shockwave on bone healing is most certainly the activation of osteoblasts through integrin activation (Rubin, Rubin & Jacobs, 2006) and differentiation of mesenchymal stem cells Chen et al. (2004).
In an excellent review article on this subject Wang (2012) said shockwave also has an influence on superoxide which mediates induction of ERK-dependent osteogenic transcription factor (CBFA-1) and mesenchymal cell differentiation toward osteoprogenitors (Wang et al., 2002). Extracorporeal shockwave promotes bone marrow stromal cell growth and differentiation toward osteo-progenitors associated with TGF-b1 and VEGF induction (Wang et al., 2002). Physical shockwave mediates membrane hyperpolarization and Ras activation for osteogenesis in human bone marrow stromal cells (wang et al., 2001). Shockwave promotes bone regeneration by the recruitment of mesenchymal stem cells and expressions of TGF-b1 and VEGF (Chen et al., 2004).
Dosage
4000 impulses per session with an energy-flux density (EFD) of 0.40 mJ/mm2 1 session per week for 4 weeks (Cacchio et al. 2009). Of interest, of the 8 people who did not recover (from the 34 patients they had) 7 showed lower levels of OC and bALP which lead the authors to conclude that a higher energy level may have worked (Cacchio et al, 2009). This would fit with the work of Wang et al. (2004) in acute fractures.
Bone Healing (necrosis):
Common conditions: Femoral head, Scaphoid, Keinbock’s disease (lunate), Mueller Weiss disease (navicular)
Who has studied it?
Several articles have reported positive effects of shockwave therapy for necrosis (mainly avascular necrosis of the femoral head [AVNFH]) (Kong et al., 2010, Wang et al., 2005, Ludwig et al., 2001, Lin et al., 2006, Wang et al, 2009, Wang et al., 2008). Wang et al (2008) compared 29 hips treated with ESWT and normal surgery. Significant improvements in pain and function were noted at each of the time intervals favoring the ESWT and there was a decrease in the size of the lesion in the ESWT group (Wang et al., 2005, Wang et al., 2008). It appears that ESWT is effective in the retardation or prevention of collapse of the femoral head in early AVNFH. The application of ESWT was also found effective in the treatment of corticosteriod induced AVNFH in patients with systemic lupus erythematosus (Lin et al., 2006). Wang et al (2009) compared 26 hips in patients with systemic lupus erythematosus with a control group, They concluded that ESWT for AVNFH had comparable effects to that for AVNFH in non-SLE patients (Lin et al., 2006). This could have implication for other patients with steroid induced bone loss.
Anatomical effects
ESWT has been shown to have effects on local circulation (Wang, 2012) as well as histopathological changes and immunohistochemical alterations.
Biological effects
ESWT has been shown to increase BMP-2 protein and mRNA, and up-regulation of VEGF expression in necrotic subchondral bone of the femoral head. The up-regulation of VEGF may play a role inducing the in-growth of neovascularization and improvement in blood supply to the femoral head (Ma et al., 2008, Ma, Zeng & Li, 2007). These findings are in concert with the findings of Wang (2012). ESWT was shown to promote angiogenesis and bone remodeling and regenerative effect in AVNFH (Wang et al., 2008).
Dosage
1500 impulses of shockwave at 0.62 mJ/mm2 energy flux density, four points used each 1.0 cm apart and a total of 6000 shocks were applied to the femoral head as a single session (Wang et al. 2005).
Bone Healing (around metal implants):
Common conditions, Knee replacement, Hip replacement, ACL (screw), Bicep insertion, Pectoralis major insertion, Rotator cuff repair, Pins and plates for stabilisation (Open reduction internal fixation or ORIF).
Who has studied it?
In 2005 Wang et al. produced an article looking at the effects of shockwave on the ACL – bone – metal screw/implant interface. Using an animal model they were able to show that shockwave improved the anchoring of the ACL via the screw at 1, 2, 4, 8, 12 and 24 weeks.
Anatomical effects
In the study (Wang et al. 2005) there was significantly more trabecular bone around the tendons. The contacting between bone and tendon was significantly better. The tensile strength of the tendon-bone interface was significantly higher as was pull out strength, although similar modes of graft failure were noted between the two groups.
Biological effects
The increased eNOS, VEGF-A, PCNA and BMP-2 expressions are all thought to improve the interface between a metal implant and the structure it is attaching from and to. The increased number of new-vessels at the tendon-bone interface is also a factor in improving stability.
Dosage
500 impulses of shockwave at 0.18 mJ/mm2 energy flux density. Single session (Wang et al. 2005).
Bone Healing (osteochondral bone OA):
Common conditions: Osteoarthritis
Who has studied it?
In 2001, researchers at Colorado State University evaluated the mechanism of action of ESWT for induced osteoarthritis in equine patients (we like equine studies as horses aren’t as easy to placebo). The study evaluated the efficacy of ESWT in reducing lameness associated with OA (ORC, 2003). In the study, ESWT performed better than both control groups in reducing lameness. Another key observation was that ESWT significantly reduced synovial fluid total protein, a parameter of synovitis. More recently, a new publication by Moretti et al. (2008) found a variety of ways in which ESWT modifies degenerative joint disease. While there are many aspects of OA that are still under investigation, there are a variety of physical and chemical aspects proven to be accountable for the development and advancement of osteoarthritis that shockwave can address. As a disease modifying agent, using ESWT on patients earlier on in the disease timeline could protect the joint and slow the onset of OA symptoms (Moretti et al., 2008).
Anatomical effects
There are multiple pathways to degradation all leading to the same outcome. Moretti et al. (2008) said that ESWT can alter the process of OA breakdown as it mediates a variety of pathways. Three key attributes of OA chondrocyte development affected by shockwave are:
- a decrease in beta 1 integrin, which seems to be an early event that begins the degradation process
- an increase in tumor necrosis factor-alpha (TNF-α)
- an increase in interleukin10 (IL-10).
Biological effects
TNF-α contributes to the advancement of OA by activating matrix metalloproteinase (MMP) production by chondrocytes which induce chondrocyte apoptosis and extracellular matrix (ECM) breakdown, and by working with other cytokines to degrade the cartilage matrix. Increased levels of IL-10 are also confirmed to be a key contributing factor to the acceleration of OA. This degradation process is cyclical: as chondrocytes breakdown, these chondrocytes inflame synovial membrane, and osteoblasts produce more TNF-α and IL-10. Osteoarthritic chondrocytes express low beta 1 integrin and high TNF-α and IL-10 levels. In their study Moretti et al (2008) showed ESWT was able to down regulate levels of TNF-α and IL-10 in OA chondrocytes to normal levels. Moretti et al (2008) said that the reduction of TNF-α as a result of ESWT can be considered a protective effect as it may prevent MMP activation and cartilage breakdown.
Dosage
Two different levels of shocks and two different energy densities have been shown to be effective (Moretti et al, 2008). 500 or a 1000 impulses of shockwave will be effective at 0.055mJ/mm2 or 0.17mj/mm2 energy flux density. All 4 combinations of these settings worked!
Bursitis:
Common Conditions: Metatarsal, Retro calcaneal, Pes anserinus, Infra patella (house maids knee), Supra patella, Pre patella (clergyman’s knee), popliteal bursa (bakers cyst), Trochanteric, Ischial, Sub acromial, Deltoid, Olecranon.
Who has studied it
There are many research studies on shockwave and it’s use in bursitis. Most of the studies published are in greater trochanteric (GT) bursitis making this the largest study group. Furia et al. (2009) compared outcomes of two groups of patients with chronic greater trochanteric pain syndrome. The study group received low-energy shockwave (SWT). The control group other therapies. At 1, 3 and 12 months follow-up, all values were significantly improved from the baseline status in both groups. However the patients undergoing SWT improved significantly more than those in the other therapies (control) group (P, 0.001). 76.5% of the patients in the SWT group who participated in regular sporting activities were able to return to their preferred sports. At final follow-up, the number of patients with excellent and good results were significantly higher after shockwave (P, 0.001). In a quasi-randomized trial, Rompe et al. (2009) compared exercise to corticosteroid injection and shockwave. One month follow up showed, corticosteroid success rate, 75%; exercise 7%; shockwave 13%. At 4 months, radial SWT led to significantly better results (68%) exercise (41%) and corticosteroid injection (51%). Fifteen months follow up radial SWT (74%) and exercise (80%) were significantly more successful than was corticosteroid injection (48%). At 4 months from baseline a significantly higher return to sport was reported after shockwave than the other two interventions. In their excellent review article Del Buono et al. (2012) said repetitive low-energy radial SWT without local anesthesia did not result in early pain relief, but provided a beneficial effect over months, with a success rate of 68% at 4 months and 74% at 15 months. Rompe et al. (2009) evaluated the effects of SWT on patients with GT bursitis which had already been treated conservatively but had been unresponsive. The mean results for the shockwave group were statistically improved at 1, 3 and 12 months after treatment compared with the control group. At the 12 months assessment, the shockwave patients had significantly higher excellent and good results compared with the control group patients (79% vs. 36%). No patient reported complications and no patient required additional treatment.
Anatomical effects
Shockwave can improve the angiogenetic growth factors, which in turn induce neovascularization and improve blood supply at the junction between the bursa and the surrounding tissues. Shockwave therapy alleviates pain by the induction of neovascularization and improvement of blood supply to the tissue. It also initiates repair of chronically inflamed tissues by tissue regeneration.
Biological effects
Wang et al. (2001) have shown that shockwave therapy releases angiogenetic growth and proliferating factors including eNOS, VEGF, and PCNA. The eNOS and VEGF began to rise in as early as one weekend, remained high for 8 weeks, then declined to baseline in 12 weeks.
Dosage
Furia et al. (2009) suggested that three weekly treatments with 2,000 impulses of low-energy shockwave at 0.18 mJ/mm2 (3 bar or 120mj) appears to be an effective therapy for bursitis with significant alleviation of pain and improvement in function.
Pain:
Common conditions: Allodynia and Hyperalgesia
Who has studied it
Many studies report on how extracorporeal shock waves might create pain relieving actions. These studies are normally anatomically defined i.e. they are problem specific and divided into regions with very specific pathologies and pathophysiology (Benjamin et al. 2006) . Maier et al (2003) and Wess (2005) found substance P and prostaglandin E2 release after shockwave application to the rabbit femur. Hausdorf et al. (2008) Wess (2005) said shockwave application to the distal femur of rabbits diminishes the number of neurons immunoreactive for substance P in dorsal root ganglia at L5 level. Takahashi et al (2003) and Cleveland et al. (2007) demonstrated that application of shock waves to rat skin decreases calcitonin gene-related peptide (CGRP) immunoreactivity in dorsal root ganglion neurons. Hausdorf et al (2008) showed selective loss of unmyelinated nerve fibers after extracorporeal shockwave application to the musculoskeletal system. Holzer (1998) and Richardson & Vasko (2002) both showed activation of peripheral small diameter sensory neurons by local depolarization, axonal reflexes or dorsal root reflexes releases substance P and CGRP. Both substances then act on target cells in the periphery such as mast cells, immune cells and vascular smooth muscle cells, thus producing inflammation. This neurogenic inflammation, is an inflammatory symptom that results from the release of substances from primary sensory nerve terminals. Chronic inflammation has been shown to contribute to the etiology of pain in tennis elbow and chronic plantar fasciitis (LeMelle, 1990 and Schepsis, 1991). Another study shows the contribution of substance P (as well as interleukin 1 alpha and transforming growth factor beta1) in the pathological process of tennis elbow, without apparent infiltration of inflammatory cells (Uchio 2002). Depletion of substance P has been demonstrated to reduce inflammation of paws and joints in animals (Lam and Ferrell, 1991, Cruwys et al., 1995, Garrett et al., 1997). Because of these effects Maier et al. (2003) said it is reasonable to hypothesise that neurogenic inflammation plays an important role in pathology (in tennis elbow and chronic plantar fasciitis), and reduction of substance P in the target tissue in conjunction with reduced synthesis of this molecule in dorsal root ganglia cells (Hausdorf et al. 2008) plays an important role in ESWT-mediated long-term analgesia in the treatment of these diseases. Schmitz and DePace (2009) went further and said selective destruction of unmyelinated nerve fibers within the focal zone of the shock waves (Hausdorf et al. 2008) might also contribute to this analgesia. A key fact to remember is shockwave preferentially targets C nerve fibers. Unmyelinated C-fibers are known to be responsible for throbbing, chronic pain (Kandel et al. 2000).
Anatomical effects
Shockwave can influence pain at both the neural and biological levels. They do this through improved blood flow (Zimmermann et al., 2009, Frairia & Berta, 2011), reducing muscle tension/stiffness (Zimmermann et al., 2009), reduction of pain through various mechanisms (Jeon et al. 2012) and generation of action potentials (Schelling et al. 1994).
Biological effects
Substance P is concentrated in unmyelinated C-fibers and lightly myelinated A-nerve fibers and is released at central and peripheral terminals of sensory nociceptive neurons after shockwave (Keen et al., 1982, Malcangio and Bowery, 1999, Snijdelaar et al., 2000). CGRP is a marker of sensory neurons typically involved with pain perception and goes hand in hand with substance P (Gibbins et al., 1985). Activation of peripheral sensory neurons by local depolarization releases substance P and CGRP. Both substances then act on target cells such as mast cells, immune cells and vascular smooth muscle cells, thus producing inflammation.
Dosage
Weekly treatments with 2,000 impulses of low-energy shockwave at 0.06 mJ/mm2 appears to be an effective therapy with significant alleviation of pain and improvement in function.
Antibacterial:
Common conditions: Infection, Infected wounds, Cysts.
Who has studied it
In vitro studies have demonstrated highly significant bactericidal effects of ESWT on Staphylococcus aureus and on different gram-positive and gram-negative pathogens such as Staphylococcus epidermidis, Enterococcus faecium and Pseudomonas aeruginosa and this efficacy has been confirmed in vivo (Gerdesmeyer et al., 2005). So far, shockwave has not been applied to infected target areas since it may induce systemic spread of bacteria with bacteraemia and the risk of secondary infection or parenchymal abscess formation. However, the risk of bacterial spread after the application of ESW to an infected target area has not yet been adequately studied and only single case reports have been documented (Kamanli et al., 2001, Zannoud et al., 2003). Conversely, there is evidence that ESW elicits a significant energy-dependent bactericidal effect. Bacterial killing by ESW has been shown for bacteria with killing rates of more than 99% (von Eiff et al., 2002, Gerdesmeyer et al., 2005, Gollwitzer et al., 2004). Additionally, positive effects of ESW on bone infections have been observed in a rabbit model of chronic osteomyelitis without systemic bacterial spreading (Gollwitzwer et al, 2009). This could not only allow safe application of ESW in infected cases, but might also provide a rationale for the treatment of chronic bone and soft tissue infections. Further study is warranted for infections such as osteomyelitis or endocarditis.
Anatomical effects
Direct destruction of cells through spalling effect, cavitation or tension
Biological effects
Changes in membrane potential are most likely the cause of the biological effect, DNA alterations, modulation of gene activity, and even altering the integrity of the cell itself – transient permeabilization of the membrane (Gambihler & Delius, 1992, Gambihler, Delius & Ellwart, 1994).
Dosage
Bacteria were reduced with 0.96 mJ/mm² and 0.59 mJ/mm² treatment intensities using 4000 or 12000 shocks (0.59 @ 4000 killed 43.3%). Basically the higher levels worked better (von Eiff et al., 2002, Gerdesmeyer et al., 2005, Gollwitzer et al., 2004).