High-energy Shock Waves Research Articles

Firewalls at exponentially late times

We consider a version of the typical state firewall setup recently reintroduced by Stanford and Yang, who found that wormholes may create firewalls. We examine a late-time scaling limit in JT gravity in which one can resum the expansion in the number of wormholes, and we use this to study the exact distribution of interior slices at times exponential in the entropy. We consider a thermofield double with and without early perturbations on a boundary. These perturbations can appear on interior slices as dangerous high energy shockwaves. For exponentially late times, wormholes tend to teleport the particles created by perturbations and render the interior more dangerous. In states with many perturbations separated by large times, the probability of a safe interior is exponentially small, even though these would be safe without wormholes. With perturbation, even in the safest state we conceive, the odds of encountering a shock are fifty-fifty. One interpretation of the phenomenon is that wormholes can change time-ordered contours into effective out-of-time-ordered folds, making shockwaves appear in unexpected places.

Feasibility study on the micro-forming of novel metal foil arrays based on submerged cavitating water-jet impingement

With the increasing demand for metal foil parts with micro-array structures in micro-electromechanical systems (MEMS), it is urgent to explore a novel array micro-forming technology with high efficiency, low cost, and high flexibility. The cavitation water jet uses the high-energy shock wave generated by the collapse of the cavitation bubble group as the loading force. It has the characteristics of large range of action, uniform pressure distribution, and can realize large-area array micro-forming processing. To verify the feasibility of cavitating water jet array micro-forming, this paper performs cavitating water jet array micro-forming on 304 stainless steel foil with a thickness of 80 μm, and analyzes the variation of cavitation bubbles collapse impact zone with target distance. The effects of target distance and impact time on the forming quality of metal foil array micro-holes were studied from the aspects of forming depth, surface roughness, and thickness thinning rate. The results show that the forming depth and uniformity of the array micro-holes located in the cavitation collapse area increase with time. However, with the increase of target distance, the forming depth increases first and then decreases. When the target distance is L = 120 mm, the forming depth reaches the maximum. The surface roughness ( Ra) of the array micro hole is Ra = 1.54 μm. The thickness thinning rate of the micro-forming parts is between 2% and 10%, and the maximum thickness thinning rate in the die fillet area is 13.5%. This paper provides a novel processing method for manufacturing metal foil parts with micro array structure.

Ultrasound-Induced In Situ Dopamine Polymerization and Deep Mucosal Penetration for Intraluminal Drug Administration.

Prolonging the residence time of drugs in the lumen and propelling them into deep lesions are highly desired for intraluminal drug administration. However, rapid drug efflux caused by dynamic intraluminal contents limits sustained drug concentrations, causing poor pharmaceutical absorption and reduced efficacy. Here, we combined theory and experiments to demonstrate a distinctive drug delivery strategy using clinically available medical ultrasound technology. Through ultrasound-induced in vivo dopamine polymerization and rapidly propelling high-energy shock waves, the resultant drug formulations can tolerate a variable intraluminal environment and penetrate deep mucosa. As a result, this ultrasound-mediated in situ adhesion and self-propelled technique signal a secure and universal strategy for the rapid coating of functional adhesion layers in vivo. Theoretically, this strategy is applicable to any hollow tissue, where ultrasound is accessible.

Long-term experiences with high-energy shock wave therapy in the management chronic phase Peyronie’s disease using two different electromagnetic lithotripters

BackgroundExtracorporeal shock wave lithotripsy represents one option for the non-surgical management of Peyronie’s disease. Despite promising results, several questions are still pending. We want to present the long-term results of a retrospective study using high-energy extracorporeal shock wave lithotripsy.Material and methodsWe evaluated retrospectively 110 patients treated between 1996 and 2020 at the Department of Urology, SLK Kliniken Heilbronn for chronic phase Peyronie’s disease using two electromagnetic lithotripters (Siemens Lithostar Plus Overhead Module, Siemens Lithoskop) applying high-energy shock waves under local anesthesia and sonographic or fluoroscopic control. A standardized questionnaire focused on the change in pain, curvature, sexual function and the need of penile surgery.ResultsIn 85 of the 110 patients (mean age 54 years) we had sufficient data for evaluation. The median follow-up was 228 (6–288) months. There were no significant complications. Pain reduction was achieved in all patients, 65 (76%) patients were free of pain. Improvement of penile curvature was achieved in 43 patients (51%) ranging from 25% improvement (deflected angle < 30°) to 95% (angle 30–60°). 59 patients (69%) reported problems with sexual intercourse, 40 of those (68%) reported improvement. Only 9 (10.5%) patients underwent surgical correction. We did not observe any significant differences between both electromagnetic devices with stable long-term results.ConclusionsHigh-energy shock wave therapy delivered by two standard electromagnetic lithotripters is safe and efficient providing stable long-term results. In cases with significant plaque formation, the concept of high-energy ESWT should be considered in future studies.

Shock Wave-Activated Silver-Loaded Biopolymer Implant Coating Eliminates Staphylococcus epidermidis on the Surface and in the Surrounding of Implants.

Bacterial biofilms on foreign surfaces are considered a primary cause of implant-related infections, which are challenging to treat. A new implant coating was developed, containing anti-infective silver within a biocompatible polymer carrier substance. In addition to its passive effect on the implant surface, highly concentrated anti-infective silver can be released as needed via the application of high-energy shock waves. This intervention could be applied transcutaneously in a clinical setting without the need for additional surgery. We investigated the inhibition of biofilm formation and the effectiveness of eradication after activation of the coating via shock waves in an in vitro biofilm model using Staphylococcus epidermidis RP62A. This was performed via scanning electron microscopy and quantitative microbiology. Additionally, we examined the cytotoxicity of the new coating on normal human fibroblasts and Saos-2 osteoblast-like cells, depending on the silver concentration. All studies were compared to uncoated titanium surfaces Ti6Al4V and a conventional electroplated silver coating. Cytotoxicity toward normal human fibroblasts and Saos-2 osteoblast-like cells increased with higher silver content but remained tolerable at 6%. Compared to uncoated Ti6Al4V and the electroplated silver coating, the new coating with a silver content of 4% and 6% exhibited a significant reduction in adherent bacteria by a factor of approximately 1000. This was also evident via microscopic examination of the surface morphology of the biofilms. Furthermore, following shock wave activation, no bacteria were detectable on either the implant or in the surrounding fluid after a 24 h period.

Effective combination of biocompatible zinc oxide nanocrystals and high-energy shock waves for the treatment of colorectal cancer

BackgroundColorectal cancer (CRC) is the third most diagnosed tumor worldwide, with a very high mortality rate, second only to lung cancer. Current treatments, such as surgery, chemotherapy or radiotherapy, are not effective enough and show several limitations. Among the emerging strategies, nanomedicine offers very powerful tools in cancer treatment. Recently, the combination of nanoparticle antitumor effect with a triggering external stimulation was formulated to boost up the cytotoxic activity.ResultsIn this work, we show the synergistic effect of oleic acid-capped zinc oxide nanocrystals (ZnO NCs) and mechanical high-energy shock waves (SW) in the treatment for CRC cells, in vitro. We tested two different types of ZnO NCs synthetized in our laboratory, the basal undoped ZnO NCs and the iron-doped ones (Fe:ZnO NCs). The presence of the oleic acid capping and the further amino-propyl functionalization guarantee a high colloidal stability to both NCs, while the iron doping confers to Fe:ZnO NCs interesting magnetic properties useful for imaging applications in a clinical perspective. Thus, the iron-doped ZnO NCs are very attractive as potentially theranostic nanoparticles, allowing both stimuli-responsive therapy and magnetic resonance imaging.Importantly, two colon adenocarcinoma cell lines, the HT-29 and the Dukes’ type C Colo 320DM cells were tested, both showing a good bio-tolerance and internalization rates of NCs. With the aim of eradicating the CRC cells, the possible synergism between the undoped/iron-doped ZnO NCs and an external physical stimulus, i.e., high-energy SW, was then here investigated in vitro. We demonstrated that the combined treatment resulted in an augmentation of the antitumor activity, especially for Colo 320DM cells, when compared to controls. Moreover, a repeated and sequenced SW treatment (three times/day, 3SW) after ZnO NCs exposure resulted in a further increased mortality of CRC cells.ConclusionOur work proposes the combination of the cytotoxic activity of ZnO NCs with the SW external stimulation to obtain a booster of the antitumor activity, which warrants further investigation in vivo on CRC as well as on other tumors.Graphical

Ultrasound-Targeted Microbubble Cavitation During Machine Perfusion Reduces Microvascular Thrombi and Graft Injury in a Rat Liver Model of Donation After Circulatory Death

Ischemic cholangiopathy is a process of bile duct injury that might result from peribiliary vascular plexus (PBP) thrombosis and remains a dreaded complication in liver transplantation from donors after circulatory death (DCD). The aim of this study was to propose a mechanical method of clot destruction to clear microvascular thrombi in DCD livers before transplantation. Sonothrombolysis (STL) is a process by which inertial cavitation of circulating microbubbles entering an ultrasound field create a high-energy shockwave at a microbubble-thrombus interface, causing mechanical clot destruction. The effectiveness of STL in DCD liver treatment remains unclear. We carried out STL treatment during normothermic, oxygenated, ex vivo machine perfusion (NMP), introducing microbubbles into the perfusate with the liver enveloped in an ultrasound field. The STL livers showed reduction in hepatic arterial and PBP thrombus and decreases in hepatic arterial and portal venous flow resistance, reduced parenchymal injury as measured by aspartate transaminase release and oxygen consumption, and improved cholangiocyte function. Light and electron microscopy showed reduction of hepatic arterial and PBP thrombus in STL livers compared with controls and preserved hepatocyte structure, sinusoid endothelial morphology, and biliary epithelial microvilli. In this model, STL improved flow and functional measures in DCD livers undergoing NMP. These data suggest a novel therapeutic approach to treat PBP injury in DCD livers, which may ultimately increase the pool of grafts available to patients awaiting liver transplantation.

Extracorporeal Shock Wave Treatment for Calcifying Tendinitis of the Shoulder: A Case Report and Literature Review

Background: Calcifying tendinitis of the shoulder (CTS), also known as rotator cuff calcific tendinitis, is a self-limiting shoulder disorder primarily characterized by inflammation surrounding hydroxyapatite crystal deposits in the tendons of the rotator cuff. Given the specific characteristics of the shoulder joint and the uncertainty regarding the efficacy of various treatments for CTS, no standardized treatment protocol has been established. However, numerous studies have demonstrated that extracorporeal shock wave therapy (ESWT) is effective in alleviating pain and improving joint function in patients with calcifying tendinitis of the shoulder. The therapeutic process works using high-energy shock waves to break down deposits of calcification, reduce local inflammation, and promote tissue healing. The purpose of this article is to present a case of symptomatic calcifying tendinopathy involving the rotator cuff and further demonstrate that ESWT has good efficacy in the treatment of musculoskeletal diseases. Results: In this case, a 39-year-old woman with a 6-month history of shoulder pain and limited range of motion (ROM) was diagnosed with calcifying tendinitis of the shoulder. A single session of shock wave therapy resulted in the complete resolution of calcific deposits and the patient’s symptoms, leading to a return to her normal ROM and improved quality of life. Conclusion: ESWT has been shown to be a good alternative to surgery for the treatment of calcifying tendinitis of the shoulder (CTS). It can significantly alleviate pain, improve shoulder function, and reduce the average size of calcium deposits. It might be the first choice for treating shoulder tendinopathy due to its effectiveness and safety. Keywords: Calcifying tendinitis, Shoulder pain, Extracorporeal shock wave treatment, Case report

The use of high-energy shock wave treatment as pre-activation of sintering high-entropy solid solutions of transition metal borides and carbides

Synthesis of solid solutions of transition metal borides (NbB2, TaB2, HfB2 and ZrB2) and carbides (NbC, TaC, HfC, ZrC and VC) was carried out via sintering the individual components without applying pressure. To activate the interaction of the components, the initial powders were processed by high-energy shock wave treatment (HESWT). HESWT enables the formation of homogeneous solid solution for a mixture of carbides; however, this method did not give the desired results for a mixture of transition metal borides, likely due to the higher strength of borides crystal lattice in comparison with carbides.

Nanotechnological engineering of extracellular vesicles for the development of actively targeted hybrid nanodevices

BackgroundWe propose an efficient method to modify B-cell derived EVs by loading them with a nanotherapeutic stimuli-responsive cargo and equipping them with antibodies for efficient targeting of lymphoma cells.ResultsThe post-isolation engineering of the EVs is accomplished by a freeze–thaw method to load therapeutically-active zinc oxide nanocrystals (ZnO NCs), obtaining the so-called TrojanNanoHorse (TNH) to recall the biomimetism and cytotoxic potential of this novel nanoconstruct. TNHs are further modified at their surface with anti-CD20 monoclonal antibodies (TNHCD20) achieving specific targeting against lymphoid cancer cell line. The in vitro characterization is carried out on CD20+ lymphoid Daudi cell line, CD20-negative cancerous myeloid cells (HL60) and the healthy counterpart (B lymphocytes). The TNH shows nanosized structure, high colloidal stability, even over time, and good hemocompatibility. The in vitro characterization shows the high biocompatibility, targeting specificity and cytotoxic capability. Importantly, the selectivity of TNHCD20 demonstrates significantly higher interaction towards the target lymphoid Daudi cell line compared to the CD20-negative cancerous myeloid cells (HL60) and the healthy counterpart (lymphocytes). An enhanced cytotoxicity directed against Daudi cancer cells is demonstrated after the TNHCD20 activation with high-energy ultrasound shock-waves (SW).ConclusionThis work demonstrates the efficient re-engineering of EVs, derived from healthy cells, with inorganic nanoparticles and monoclonal antibodies. The obtained hybrid nanoconstructs can be on-demand activated by an external stimulation, here acoustic pressure waves, to exploit a cytotoxic effect conveyed by the ZnO NCs cargo against selected cancer cells.Graphical

Safe and Effective Treatment of Compromised Clavicle Fracture of the Medial and Lateral Third Using Focused Shockwaves.

A delay or failure to heal is the most common possible complication in clavicle fractures, especially in cases primarily treated conservatively. As the current standard therapy, surgical revision achieves good healing results, but is associated with potential surgery-related complications. Shockwave therapy as a non-invasive therapy shows similar reasonable consolidation rates in the non-union of different localizations, but avoids complications. Compromised clavicle fractures in the middle and lateral third treated with focused high-energy shockwave therapy were compared with those treated with surgical revision (ORIF). In addition, a three-dimensional computer simulation for evaluating the pressure distribution during shockwave application accompanied the clinical study. A comparable healing rate in bony consolidation was achieved in both groups. Significantly fewer complications, however, occurred in the shockwave group. The simulations showed safe application in this instance, particularly in avoiding lung tissue affection. When applied correctly, shockwaves represent a safe and promising therapy option for compromised clavicle fractures in the middle and lateral third.

Effects of High-Energy Extracorporeal Shockwave Therapy on Pain, Functional Disability, Quality of Life, and Ultrasonographic Changes in Patients with Calcified Rotator Cuff Tendinopathy.

Objective The current trial was designed to evaluate the effects of high-energy shockwave therapy on objective and subjective outcomes among participants with calcified rotator cuff tendinopathy. Methods This parallel-group, randomized trial consists of 42 patients affected by calcific tendinopathies divided into two groups of 21 participants. Patients having calcified tendinopathy aged between 30 and 65 years with type A or B calcification were selected in the trial after signing the written consent form. Participants in the ESWT+RPT group received eight sessions of shockwaves, while the RPT group was treated by routine physical therapy. About 2000 shockwaves of 0.32 mJ/mm2, 120 Hz per treatment, were given as 12 sessions for the first six weeks (2 sessions/week). Pain intensity and shoulder functional ability, ultrasonographic changes, and quality of life were assessed with the numeric pain rating scale (NPRS), Constant-Murley score (CMS), ultrasonography, and Western Ontario rotator cuff index (WORC). Results There were significant differences regarding NPRS and CMS between the two groups, at baseline and 6th and 12th weeks after intervention (p < 0.05). Within-group differences also showed statistically significant results after treatment (all p < 0.05). Significant results were seen in the WORC and ultrasonographic results pre- and posttreatment; more significant findings were found in the experimental group as compared to others. Conclusion High-energy shockwave therapy has been proved to be effective and thus strongly recommended for the management of calcified rotator cuff tendinopathy, improving the pain, functionality, and quality of life of these participants and decreasing the size of calcified deposits. Shockwave therapy is proved to be superior to routine physiotherapy.

Smart Shockwave Responsive Titania-Based Nanoparticles for Cancer Treatment.

Nanomedicine is an emerging treatment approach for many cancers, characterized by having high sensitivity and selectivity for tumor cells and minimal toxic effects induced by the conventional chemotherapeutics. In these context, smart nanoparticles (NPs) are getting increasingly relevant in the development of new therapies. NPs with specific chemical composition and/or structure and being stimuli-responsive to magnetic, light or ultrasound waves are new promising tools. In the present work, amorphous-titania propyl-amine functionalized (a-TiO2-NH2) NPs, coated with bovine serum albumin (BSA), are stimulated with high energy shock waves to induce cytotoxic effects in cancer cells. First, a new method to coat a-TiO2-NH2 NPs with BSA (a-TiO2-NH2/BSA) was proposed, allowing for a high dispersion and colloidal stability in a cell culture media. The a-TiO2-NH2/BSA NPs showed no cancer cell cytotoxicity. In a second step, the use of shock waves to stimulate a-TiO2-NH2/BSA NPs, was evaluated and optimized. A systematic study was performed in in vitro cell culture aiming to impair the cancer cell viability: NP concentrations, time steps and single versus multiple shock waves treatments were studied. The obtained results highlighted the relevance of NPs design and administration time point with respect to the shock wave treatment and allow to hypothesize mechanical damages to cells.

What is the optimal frequency in shock wave lithotripsy for pediatric renal stones? A prospective randomized study.

The aim of the study is to compare the effects of varying frequency rates (60, 90, and 120SWs/min) on the stone free rate and complication rates of pediatric SWL. 75 children with renal stones were divided into 3 groups depending on the SW frequency applied. Group 1. low (60SWs/min), Group 2. intermediate (90 SWs/min) and Group 3. high (120 SWs/min) frequency. Patient demographics (age, gender, BMI), stone (location, size, laterality), and SWL (total number of sessions, shock waves, anesthesia time) related parameters were documented. Postoperative success, complication rates, and the need for additional interventions were comparatively evaluated. There was no significant difference regarding the patient demographics, stone characteristics, SWL parameters, postoperative complication rates, need for additional interventions as well as efficacy quotient between all (p > 0.05). The stone free rates were significantly lower in cases with high frequency, whereas there was no statistically significant difference between the intermediate and low frequency groups (p > 0.05). Although not statistically significant; low frequency application may be more advantageous than intermediate as lower number of high energy shock waves required which may cause less tissue damage. On the other hand, despite lack of a statistically significant difference, relatively longer anesthesia time may constitute a disadvantage for lower frequency. We believe that considering the growing nature of the child kidney application of low frequency (60SWs/min) will be advantageous. However, we believe that further studies with larger series of cases are needed to make a clear-cut differentiation between low and intermediate SW applications.

Water-Jet Cavitation Shock Bulging as Novel Microforming Technique

With the continuous expansion of the application range of microelectromechanical systems, microdevice forming technology has achieved remarkable results. However, it is challenging to develop new microforming processes that are low cost, environmentally friendly, and highly flexible; the high-energy shock wave in a cavitation bubble’s collapse process is used as the loading force. Herein, a new process for the microbulging of the water-jet cavitation is proposed. A series of experiments involving the water-jet cavitation shock microbulging process for TA2 titanium foil is performed on an experimental system. The microforming feasibility of the water-jet cavitation is investigated by characterizing the shape of the formed part. Subsequently, the effects of the main parameters of the water-jet cavitation on the bulging profile, forming depth, surface roughness, and bulging thickness distribution of TA2 titanium foil are revealed. The results show that the plastic deformation increases nonlinearly with the incident pressure. When the incident pressure is 20 MPa, the maximum deformation exceeds 240 μm, and the thickness thinning ratio changes within 10%. The microbulging feasibility of water-jet cavitation is verified by this phenomenon.

Research on the water cavitation peening process and mechanism of TC4 titanium alloy

Cavitation water shot peening is a new processing method of surface strengthening and modification that utilizes the cavitation bubbles in the cavitation water jet to destroy high-energy shock waves, causing the cavitation groups to collapse on the surface of the material. Strengthening research on TC4 titanium alloy cavitation water jet peening is limited. The process of cavitation water shot peening strengthening is small, and the mechanism of residual stress generation is not yet clear. Therefore, five typical shot peening strength tests of TC4 titanium alloy are taken as examples in this paper. Experiments and mechanistic studies are carried out through macro-micromorphology, metallographic structure and XRD analysis, microhardness, and residual stress methods. The research results are as follows: as the shot peening strength increases, the surface roughness Ra and the depth of the plastic deformation layer gradually increase, and the depth of the plastic deformation layer is saturated at 55–60 μm; the depth of the influence of the microhardness and residual stress reaches 130 μm; and the surface grains gradually refine and develop to the nanometre level.

Impact of shock waves on glass wool composition and properties

Glass wool finds its application in soundproofing materials and insulation. This paper studies the effect of high-energy shock waves on glass wool fibres using modified Reddy shock tube. Changes in composition and properties of fibres are reported through SEM analysis. With driver pressure of 6.79 bar, Mach number, maximum pressure and temperature achieved are 1.46, 4.845 atm and 482.91 K respectively. Due to diaphragm material, carbon content of 2.92% by weight is observed in shocked specimen. SEM images show curliness in fibers, increased number and uniform distribution of binder clusters and air voids resulting in enhanced strength, hardness and insulation properties of fibres.

Comparison of scaphoid reconstruction with a non-vascularised bone graft, with and without shock waves; preliminary results

Focused, high energy shock wave therapy (ESWT) stimulates bone healing by neo-angiogenesis and activating osteocytes. This study investigates if applying an ESWT intraoperatively improves and accelerates the healing of a scaphoid nonunion after reconstruction using a non-vascularized bone graft. In this prospective, ongoing study, patients with a scaphoid reconstruction using a non-vascularized bone graft and stabilization for non-union, are randomized for having additionally an intraoperative ESWT (intervention group) or not (control group). In 6 weeks-intervals, patients have a clinical and radiological follow-up, including a CT scan at 12, 18, and if needed 24 weeks postoperatively. The intervention group and the control group are compared with regard to the proportion of the bridged contact area between scaphoid and the bone graft at 12, 18, and 24 weeks postoperatively and the rate of the healed scaphoids at the final follow-up. At time of this data analysis, 35 patients of the intervention group and 33 patients of the control group had passed all of their scheduled follow-ups. Twenty-four weeks postoperatively, the scaphoids of 27 patients (77 %) in the intervention group and those of 20 patients (61 %) in the control group were healed. At 12, 18, and 24 weeks, the contact area between scaphoid and the bone graft proximally was bridged by 80 %, 84 %, and 86 % respectively in the intervention group, and 74 %, 81 %, and 84 % in the control group. Distal to the bone graft, the gap was bridged by 91 %, 94 %, and 95 % for the intervention group and 77 %, 90 %, and 94 % for the control group. At 12 weeks postoperatively, the proportional healing distal to the bone graft was significantly higher after ESWT. A single, intraoperative ESWT improves the healing rate of scaphoid reconstruction with a non-vascularized bone graft and accelerates the gap bridging during the first 12 weeks after surgery.

Zinc Oxide Nanocrystals and High-Energy Shock Waves: A New Synergy for the Treatment of Cancer Cells

In the last years, different nanotools have been developed to fight cancer cells. They could be administered alone, exploiting their intrinsic toxicity, or remotely activated to achieve cell death. In the latter case, ultrasound (US) has been recently proposed to stimulate some nanomaterials because of the US outstanding property of deep tissue penetration and the possibility of focusing. In this study, for the first time, we report on the highly efficient killing capability of amino-propyl functionalized ZnO nanocrystals (ZnO NCs) in synergy with high-energy ultrasound shock waves (SW) for the treatment of cancer cells. The cytotoxicity and internalization of ZnO NCs were evaluated in cervical adenocarcinoma KB cells, as well as the safety of the SW treatment alone. Then, the remarkably high cytotoxic combination of ZnO NCs and SW was demonstrated, comparing the effect of multiple (3 times/day) SW treatments toward a single one, highlighting that multiple treatments are necessary to achieve efficient cell death. At last, preliminary tests to understand the mechanism of the observed synergistic effect were carried out, correlating the nanomaterial surface chemistry to the specific type of stimulus used. The obtained results can thus pave the way for a novel nanomedicine treatment, based on the synergistic effect of nanocrystals combined with highly intense mechanical pressure waves, offering high efficiency, deep and focused tissue penetration, and a reduction of side effects on healthy cells.

Extracorporal shock wave therapy for the treatment of arthrodesis non-unions.

Non-union is a regular complication of arthrodeses. Standard treatment includes revision surgery with frequent need for re-revision due to persistent non-union. Particularly patients with concomitant diseases are at risk of secondary complications. There is a need for evaluation of alternative treatment options. The aim of this study is to provide first evidence on union-rate and pain course after focussed extracorporeal shock-wave therapy of arthrodesis non-unions. In a retrospective single-centre study, 25 patients with non-union following arthrodesis received one session of focussed extracorporeal shock-wave therapy (energy flux density 0.36mJ/mm2, 3000 impulses, 23kV, 4Hz). Radiographic and clinical results were recorded 6, 12 and 24weeks after treatment. 24 patients were followed-up. After 24weeks arthrodeses of the hand healed in 80%, of the upper ankle in 50%, of subtalar joint in 27.2% and of the midfoot in 0% of the cases. Pain decreased from 4.8 (± 2.8) points on the visual analogue scale to 3.4 (± 2.3), 2.9 (± 2.5) and 2.4 (± 2.8) points after 6, 12 and 24weeks, respectively (p < 0.0001). Our data indicate that the effect of focussed, high-energy shock wave therapy depends on body region and is effective for the treatment of non-unions of the hand as well as for pain relief. Level IV.