Ultrasound usage and dosage in sports physiotherapy

Ultrasound-Mediated Ocular Drug Delivery: From Physics and Instrumentation to Future Directions

Drug delivery to the anterior and posterior segments of the eye is impeded by anatomical and physiological barriers. Increasingly, the bioeffects produced by ultrasound are being proven effective for mitigating the impact of these barriers on ocular drug delivery, though there does not appear to be a consensus on the most appropriate system configuration and operating parameters for this application. In this review, the fundamental aspects of ultrasound physics most pertinent to drug delivery are presented; the primary phenomena responsible for increased drug delivery efficacy under ultrasound sonication are discussed; an overview of common ocular drug administration routes and the associated ocular barriers is also given before reviewing the current state of the art of ultrasound-mediated ocular drug delivery and its potential future directions.

Therapeutic Ultrasound and Shockwave Therapy for Tendinopathy: A Narrative Review

ABSTRACT

Tendon injury is prevalent and costly in the United States, comprising 45% of the 66 million musculoskeletal injuries and costing $114 billion annually. Surgical and therapeutic methods, such as arthroscopic surgery, dry needling, and physical therapy, produce mixed success in reintroducing a healing response in tendinopathy due in part to inconsistent dosing and monitoring. Ultrasound is one therapeutic modality that has been shown to noninvasively induce bioeffects in tendon that may help promote healing. However, results from this modality have also been mixed. This review compares the current state of the field in therapeutic ultrasound and shockwave therapy, including low-intensity therapeutic ultrasound, extracorporeal shockwave therapy, and radial shockwave therapy, and evaluates the efficacy in treating tendinopathies with ultrasound. We found that the mixed successes may be attributed to the wide variety of achievable parameters within each broader treatment type and the lack of standardization in measurements and reporting. Despite mixed outcomes, all three therapies show potential as an alternative therapy with lower-risk adverse effects than more invasive methods like surgery. There is currently insufficient evidence to conclude which ultrasound modality or settings are most effective. More research is needed to understand the healing effects of these different therapeutic ultrasound and shockwave modalities.

Latest Advances in the Use of Therapeutic Focused Ultrasound in the Treatment of Pancreatic Cancer

Traditional oncological interventions have failed to improve survival for pancreatic cancer patients significantly. Novel treatment modalities able to release cancer-specific antigens, render immunologically "cold" pancreatic tumours "hot" and disrupt or reprogram the pancreatic tumour microenvironment are thus urgently needed. Therapeutic focused ultrasound exerts thermal and mechanical effects on tissue, killing cancer cells and inducing an anti-cancer immune response. The most important advances in therapeutic focused ultrasound use for initiation and augmentation of the cancer immunity cycle against pancreatic cancer are described. We provide a comprehensive review of the use of therapeutic focused ultrasound for the treatment of pancreatic cancer patients and describe recent studies that have shown an ultrasound-induced anti-cancer immune response in several tumour models. Published studies that have investigated the immunological effects of therapeutic focused ultrasound in pancreatic cancer are described. This article shows that therapeutic focused ultrasound has been deemed to be a safe technique for treating pancreatic cancer patients, providing pain relief and improving survival rates in pancreatic cancer patients. Promotion of an immune response in the clinic and sensitisation of tumours to the effects of immunotherapy in preclinical models of pancreatic cancer is shown, making it a promising candidate for use in the clinic.

Effects of Therapeutic Ultrasound on Growth Plates: A Systematic Review

PURPOSE

The aim of this systematic review was to evaluate studies reporting on the effects of therapeutic ultrasound on the physis.

SUMMARY OF KEY POINTS

Eight studies were included in the final analysis, all of which were animal studies. At higher doses, studies found skin and bone necrosis and inhibition of growth, while in lower doses some studies found that ultrasound had a transient stimulatory effect on growth, increased thickness of the hypertrophic zone, and increased thickness of the whole growth plate. Overall, experimental evidence in animal models suggests that therapeutic ultrasound, even at low doses, might induce microscopic changes to the histology of the growth plate.

CONCLUSION

While we found no reports of growth disturbance in humans, given the histological changes found in animal studies, the current limited literature seems to support the recommendation that the application of therapeutic ultrasound around the physis should be avoided.

Effects of Non-thermal Ultrasound on a Fibroblast Monolayer Culture: Influence of Pulse Number and Pulse Repetition Frequency

Despite the use of therapeutic ultrasound in the treatment of soft tissue pathologies, there remains some controversy regarding its efficacy. In order to develop new treatment protocols, it is a common practice to carry out in vitro studies in cell cultures before conducting animal tests. The lack of reproducibility of the experimental results observed in the literature concerning in vitro experiments motivated us to establish a methodology for characterizing the acoustic field in culture plate wells. In this work, such acoustic fields are fully characterized in a real experimental configuration, with the transducer being placed in contact with the surface of a standard 12-well culture plate. To study the non-thermal effects of ultrasound on fibroblasts, two different treatment protocols are proposed: long pulse (200 cycles) signals, which give rise to a standing wave in the well with the presence of cavitation (I_SPTP max = 19.25 W/cm²), and a short pulse (five cycles) of high acoustic pressure, which produces a number of echoes in the cavity (I_SPTP = 33.1 W/cm², with P_max = 1.01 MPa). The influence of the acoustic intensity, the number of pulses, and the pulse repetition frequency was studied. We further analyzed the correlation of these acoustic parameters with cell viability, population, occupied surface, and cell morphology. Lytic effects when cavitation was present, as well as mechanotransduction reactions, were observed.

Using therapeutic ultrasound to promote irritated skin recovery after surfactant-induced barrier disruption

BACKGROUND

Surfactant-induced skin barrier disruption can enhance blood flow and water content in the superficial skin. The effect of therapeutic ultrasound on accelerating the recovery of superficial skin after skin barrier disruption has seldom been studied.

OBJECTIVE

To understand the effects of therapeutic ultrasound on barrier recovery, we used the sodium lauryl sulfate irritation model and treatment with ultrasound intervention.

METHODS

The study allocated 30 healthy subjects into an ultrasound group (n = 15) and a control group (n = 15), each divided into three subgroups (sodium lauryl sulfate at concentrations of 1.0%, 0.5%, and 0%). Pulsed ultrasound (1 MHz, 0.3 W/cm²_SATA) was applied to ultrasound subgroups. The treatment effect was evaluated by the recovery rate of enhanced blood flow and water content.

RESULTS

The results indicated a surfactant dose-dependent effect on blood flow, but not on water content. The recovery rates of enhanced blood flow were higher in the 0.5% and 1.0% ultrasound subgroups than in the control subgroups throughout the experiment. However, recovery rates of water content were higher in the ultrasound subgroups than in the control subgroups only on Day2.

CONCLUSIONS

Pulsed ultrasound accelerated the barrier recovery by reducing the enhanced blood flow and water content after skin barrier disruption.

Ultrasound therapy in iliopsoas hematoma

Warfarin is a commonly used anticoagulant agent that can have life-threatening complications, such as severe bleeding, which then require cessation of the treatment. Due to the widespread use of this therapy in recent years, incidences of its hemorrhagic complications have also increased significantly. In hemodynamically stable patients, it is possible to adopt conservative treatment strategies, such as ultrasound (US) therapy as an alternative. US is a physical therapy modality widely used in musculoskeletal disorders, but there is little evidence about its effectiveness for hemorrhagic complications because of the limited number of studies on this subject at present. A 77-year-old male who had been under oral anticoagulant therapy for 6½ years presented at the clinic with complaints of severe pain and numbness in the anterolateral thigh. US evaluation revealed iliopsoas hematoma. US treatment, administered as a physical therapy modality, resulted in faster resorption of the hematoma than expected. The patient fully recovered from clinically observed pain, meralgia paresthetica, and reduced patellar reflex.

Experimental Verification of Modeled Thermal Distribution Produced by a Piston Source in Physiotherapy Ultrasound

Objectives. To present a quantitative comparison of thermal patterns produced by the piston-in-a-baffle approach with those generated by a physiotherapy ultrasonic device and to show the dependency among thermal patterns and acoustic intensity distributions. Methods. The finite element (FE) method was used to model an ideal acoustic field and the produced thermal pattern to be compared with the experimental acoustic and temperature distributions produced by a real ultrasonic applicator. A thermal model using the measured acoustic profile as input is also presented for comparison. Temperature measurements were carried out with thermocouples inserted in muscle phantom. The insertion place of thermocouples was monitored with ultrasound imaging. Results. Modeled and measured thermal profiles were compared within the first 10 cm of depth. The ideal acoustic field did not adequately represent the measured field having different temperature profiles (errors 10% to 20%). Experimental field was concentrated near the transducer producing a region with higher temperatures, while the modeled ideal temperature was linearly distributed along the depth. The error was reduced to 7% when introducing the measured acoustic field as the input variable in the FE temperature modeling. Conclusions. Temperature distributions are strongly related to the acoustic field distributions.

Effects of Therapeutic Physical Agents on Achilles Tendon Microcirculation

STUDY DESIGN

Controlled laboratory study.

OBJECTIVES

To measure Achilles tendon microcirculation (total hemoglobin [THb] and oxygen saturation [StO2]) before and after the application of a physical agent in asymptomatic participants, and to compare differences between application location and physical agent dosage.

BACKGROUND

Tendon microcirculation can be altered by superficial heating or cryotherapy.

METHODS

Fifty-one healthy adults (median age, 22 years; range, 20-34 years) were recruited and randomly assigned into 1 of 4 groups. Participants in each group received an intervention consisting of 1 of the following 4 physical agents: ultrasound (n = 12), interferential current (n = 14), low-level laser (n = 11), or vibration massage (n = 14). In each group, the selected intervention was applied at 2 different doses (ultrasound, 0.8 or 1.2 W/cm(2); laser, 5.4 or 18 J) or target locations (vibration and electrostimulation, calf muscle or Achilles tendon). For each participant, each dose or target location was randomly applied to 1 randomly selected lower leg (each leg receiving only 1 of the 2 options).

RESULTS

The StO2 values significantly increased after ultrasound at both doses (P<.008), and the THb value significantly increased for the higher dose only (P<.008). Both THb and StO2 values also significantly increased in response to vibration massage targeting the Achilles tendon (P<.008), and these values were greater than those resulting from the vibration massage applied to the calf muscle (P = .003 and .002, respectively). No significant THb and StO2 differences were found after the application of interferential current or low-level laser.

CONCLUSION

Tendon microcirculation increases after ultrasound and vibration massage intervention concentrated on the Achilles tendon. These modalities may be considered for the purpose of temporarily increasing microcirculation in the tendon.

Effects of phonophoresis and gold nanoparticles in experimental model of muscle overuse: role of oxidative stress

The aim of the study described here was to investigate the effects of pulsed ultrasound and gold nanoparticles (AuNPs) on behavioral, inflammatory and oxidative stress parameters in an experimental model of overuse. Wistar rats performed 21 d of exercise on a treadmill at different intensities and were exposed to ultrasound in the presence or absence of AuNPs. The overuse model promoted behavioral changes and increased creatine kinase, superoxide dismutase and glutathione peroxidase activity, as well as the levels of superoxide, nitrotyrosine, nitric oxide, thiobarbituric acid reactive substance, carbonyl, tumor necrosis factor α and interleukin-6. These values were significantly decreased by AuNPs and by AuNPs plus ultrasound. Catalase activity remained unchanged and the glutathione level increased significantly after exposure to AuNPs plus ultrasound. These results suggest a susceptibility to anxiety as well as elevated levels of oxidative stress. However, therapeutic interventions with AuNPs plus ultrasound reduced the production of oxidants and oxidative damage and improved the anti-oxidant defense system.

Heating produced by therapeutic ultrasound in the presence of a metal plate in the femur of canine cadavers

The present study aimed to assess the heat generated by a therapeutic ultrasound (TUS) in a metal bone plate and adjacent structures after fixation to the femur of canine cadavers. Ten pairs of hind limbs were used, and they were equally distributed between groups that were subjected to 1- and 3-MHz frequencies, with each frequency testing 1- and 2-W/cm² intensities. The right hind limb was defined as the control group (absence of the metal plate), and the left hind limb was the test group (presence of the metal plate). Therefore, the control groups (CG) were denominated CGI, using TUS with 1-MHz frequency and 1-W/cm² intensity; CGII, using 1-MHz frequency and 2-W/cm² intensity; CGIII, using 3-MHz frequency and 1-W/cm² intensity; and CGIV, using 3-MHz frequency and 2-W/cm² intensity. For each control group, its respective test group (TG) was denominated TGI, TGII, TGIII and TGIV. The TUS was applied to the lateral aspect of the thigh using the continuous mode and a 3.5-cm² transducer in a 6.25-cm² area for 2 minutes. Sensors were coupled to digital thermometers that measured the temperature in different sites before (t0) and after (t1) of the TUS application. The temperatures in t1were higher in all tested groups. The intramuscular temperature was significantly higher (P<0.05) in the groups used to test the 3-MHz frequency in the presence of the metal plate. The therapeutic ultrasound in the continuous mode using frequencies of 1 and 3 MHz and intensities of 1 and 2 W/cm2 for 2 minutes caused heating of the metal plate and adjacent structures after fixation to the femur of canine cadavers.

Short-term sensory and cutaneous vascular responses to therapeutic ultrasound in the forearms of healthy volunteers

Background

Therapeutic ultrasound (US) is used for a variety of clinical pathologies and is thought to accelerate tissue repair and help with pain reduction via its thermal and nonthermal effects. The evidence on physiological effects of US on both sensory and vascular functions in humans is incomplete. Hence, the purpose of this study was to determine the short-term impact of two doses of US (3 MHz, 1:4, 0.25 W/cm², 5 min; 1 MHz, continuous, 0.8 W/cm², 3 min), on sensory and vascular responses in the healthy forearms.

Methods

Twenty healthy subjects were recruited (mean age, 29.6 ± 8.8 years) for the study. Superficial blood flow (SBF) in the distal forearms was determined using the tissue viability imaging system. Sensory perception thresholds (SPT) were determined from ring finger (C7, C8) to assess A-beta (at 2,000 Hz) and C fiber function (at 5 Hz), using a Neurometer CPT/C device. Subject’s two hands were randomly allocated to group order (AB/BA). Scores were obtained before and immediately after the application of US and control. Differences in these were analyzed using repeated measures.

Results

Both 3 MHz pulsed US and 1 MHz continuous US showed small to moderate (effect size = 0.12 to 0.68), statistically significant reductions in SBF (3 MHz, mean change = 2.8 AU and 1 MHz, mean change = 3.9 AU, p < 0.05 respectively), skin temperature (2.5°C and 1.1°C, p < 0.05), and SPT at 5 Hz (1.3 and 1 mA, p < 0.05) across time. SPT at 2,000 Hz remained unaltered by all three conditions (p > 0.05). Age and gender also had no effect on all outcome measures (p > 0.05).

Conclusion

This study demonstrated minor reductions in skin blood flow, skin temperatures, and C fiber perception thresholds immediately after 3 MHz, and 1 MHz US. The responses observed may have been due to a thermo-cooling effect of the gel or due to the direct effect of US on C fibers of median and ulnar nerves. US had a negligible effect on A-beta fibres. This would suggest that future studies looking at physiological effects of US should move towards investigating larger dosages and study the effects in patient populations.

Usage Patterns and Beliefs about Therapeutic Ultrasound by Canadian Physical Therapists: An Exploratory Population-Based Cross-Sectional Survey

PURPOSE

To explore the frequency and patterns of ultrasound (US) usage among physical therapists, to describe the most common purposes for using therapeutic US, and to investigate beliefs about therapeutic US.

METHODS

A survey was sent to 95% of physical therapists licensed to practise in the province of Alberta, Canada.

RESULTS

Of 2,269 physical therapists to whom email invitations were sent, 438 (19.3%) provided full responses. RESULTS indicate that US is still frequently incorporated into treatment regimens and is widely believed to be effective; however, the study also found a decrease in US usage over the past 15 years. While physical therapists recognize the lack of evidence for the effectiveness of US, many consider it clinically useful. Physical therapists using US rely largely on their clinical experience when making decisions about its use, but this depends on level of education: clinicians with an MScPT degree tended to base more of their US decisions on research evidence, likely because of the increasing emphasis on research evidence in graduate education.

CONCLUSIONS

Despite the questionable effectiveness of therapeutic US, physical therapists still commonly use this treatment modality, largely because of a belief that US is clinically useful. However, US usage has decreased over the past 15 years.

Comparação do ultrassom pulsado e contínuo no reparo tendíneo de ratos

No tratamento de lesões tendíneas, o uso do ultrassom surge como possibilidade terapêutica, apesar de lacunas sobre seus efeitos clínicos. O objetivo foi avaliar dois protocolos de ultrassom terapêutico sobre dor e edema após trauma tendíneo. Vinte e um ratos Wistar foram submetidos a trauma no tendão calcâneo e divididos em três grupos: sham (GS); ultrassom contínuo (GUC); e ultrassom pulsado (GUP). O trauma ocorreu sobre a face lateral do tendão calcâneo direito, com energia de 0,40 J. A dor foi avaliada pelo teste de incapacidade funcional e o edema, pelo diâmetro laterolateral. Foram realizadas avaliações previamente à lesão; após 1 hora da indução da lesão; após o 1º tratamento; 2, 8 e 24 horas após lesão; e após o 5º dia. O tratamento ocorreu em 5 dias, com transdutor de 1 MHz, durante 3 minutos, sobre o local do trauma, com dose de 0,4 W/cm² SATA. Os resultados da incapacidade funcional para GS mostraram aumento da nocicepção. Para GUC houve aumento ao comparar a avaliação 1 (AV1) com as avaliações 2 (AV2), 3 (AV3) e 4 (AV4); ao comparar AV2 com as avaliações 5 (AV5) e 6 (AV6) houve diminuição de valores. Para GUP houve aumento ao comparar AV1 com AV2 e AV3, mas ao comparar AV2 com as seguintes, houve diminuição significativa a partir de AV4. Para o edema, os grupos tratados produziram aumento inicial, com redução nas últimas avaliações. O ultrassom terapêutico produziu diminuição de dor e edema, mais precocemente para a forma pulsada.

Overview of ultrasound usage trends in orthopedic and sports physiotherapy

BACKGROUND

The purpose of this study is to examine current beliefs about the use, the clinical importance, the theoretical fundamentals and the utilization criteria of therapeutic ultrasound (TUS) among physical therapists on the clinical practice in orthopedic and sports physiotherapy in Brazil.

METHODS

A brief survey was developed based on previous studies and was sent to 55 physical therapists with advanced competency in orthopedics and sports physiotherapy. The questions addressed general topics about the professional profile and ultrasound usage and dosage.

RESULTS

Our data show the wide availability and frequent use of TUS in this sample of physical therapists. TUS is used in distinct musculoskeletal injuries and/or disorders in both acute and chronic conditions. Muscles, tendons and ligaments represented the major structures where TUS is used. Questions on the basic theory of TUS demonstrated a lack of knowledge of the ultrasound physiological effects as well as its interaction with biological tissues and TUS absolute contraindication.

CONCLUSION

A Brazilian profile about the US usage and dosage in orthopedic and sports physiotherapy is presented and highlights the need for a continuous upgrading process and further research into its effects.

O ultrassom terapêutico na medula espinhal acelera a regeneração do nervo ciático de ratos

OBJETIVO: Estudar os efeitos da irradiação ultrassônica de baixa intensidade aplicada sobre a medula espinhal na regeneração do nervo ciático de ratos após lesão por esmagamento controlado, avaliando os resultados pelo índice funcional do ciático (SFI), medido nas imagens vídeo-filmadas das plantas das patas. MÉTODOS: Dezoito ratos foram submetidos a esmagamento controlado (do nervo ciático direito e divididos em dois grupos de acordo com o tratamento: Grupo 1 (n=9), irradiação simulada; Grupo 2 (n=9), irradiação efetiva. Irradiação ultrassônica de baixa intensidade foi iniciada no 7º dia pós-operatório e aplicada diariamente por 6 semanas. Imagens das plantas das patas dos animais foram vídeo-filmadas em uma esteira transparente sob velocidade controlada a intervalos semanais até a 6ª semana de irradiação e o correspondente SFI medido com um programa de computador específico. RESULTADOS: O SFI durante a 1ª e a 6ª semana de tratamento foi de -59,12 e -12,55 no Grupo 1, e -53,31 e -1,32 no Grupo 2, indicando uma melhora de 79% e 97%, respectivamente, mas as diferenças entre os grupos somente foram significantes (p<0,05) durante a 3ª semana de tratamento. CONCLUSÃO: Os autores concluem que o ultrassom terapêutico de baixa intensidade estimula a regeneração nervosa, com significância durante a 3ª semana de tratamento. Nivel de Evidência II, Prospectivo Comparativo.

The effectiveness of therapeutic ultrasound for musculoskeletal conditions of the lower limb: A literature review

BACKGROUND

Ultrasound is suggested as one of the treatment options available for soft tissue musculoskeletal conditions of the lower limb and to this end, the objective was to review the literature and evaluate the effectiveness of therapeutic ultrasound for musculoskeletal conditions of the lower limb.

METHODS

A search of the literature published between 1975 and February 2009 was carried out. All studies that fulfilled the inclusion criteria were quality assessed and scored using the Critical Appraisal Skills Programme (CASP) appraisal tool [1] for randomised controlled trials.

RESULTS

Ten studies out of a possible fifteen were included in the review. Only one trial was considered to be high quality (score 16+), three medium quality trials (score 11-15) were identified and six trials were considered to be low or poor quality (score≤10). None of the six placebo-controlled trials found any statistically significant differences between true and sham ultrasound therapy.

CONCLUSION

This literature review found that there is currently no high quality evidence available to suggest that therapeutic ultrasound is effective for musculoskeletal conditions of the lower limb.

No midterm benefit from low intensity pulsed ultrasound after chevron osteotomy for hallux valgus

Chevron osteotomy is a widely accepted method for correction of symptomatic hallux valgus deformity. Full weight bearing in regular shoes is not recommended before 6 weeks after surgery. Low intensity pulsed ultrasound is known to stimulate bone formation leading to more stable callus and faster bony fusion. We performed a randomized, placebo-controlled, double-blinded study on 44 participants (52 feet) who underwent chevron osteotomy to evaluate the influence of daily transcutaneous low intensity pulsed ultrasound (LIPUS) treatment at the site of osteotomy. Follow-up at 6 weeks and 1 year included plain dorsoplantar radiographs, hallux-metatarsophalangeal-interphalangeal scale and a questionnaire on patient satisfaction. There was no statistical difference in any pre- or postoperative clinical features, patient satisfaction or radiographic measurements (hallux valgus angle, intermetatarsal angle, sesamoid index and metatarsal index) except for the first distal metatarsal articular angle (DMAA). The DMAA showed statistically significant (p = 0.046) relapse in the placebo group upon comparison of intraoperative radiographs after correction and fixation (5.2 degrees) and at the 6-week follow-up (10.6 degrees). Despite potential impact of LIPUS on bone formation, we found no evidence of an influence on outcome 6 weeks and 1 year after chevron osteotomy for correction of hallux valgus deformity.

Recombinant human parathyroid hormone (PTH 1-34) and low-intensity pulsed ultrasound have contrasting additive effects during fracture healing

Fracture healing is thought to be naturally optimized; however, recent evidence indicates that it may be manipulated to occur at a faster rate. This has implications for the duration of morbidity associated with bone injuries. Two interventions found to accelerate fracture healing processes are recombinant human parathyroid hormone [1-34] (PTH) and low-intensity pulsed ultrasound (LIPUS). This study aimed to investigate the individual and combined effects of PTH and LIPUS on fracture healing. Bilateral midshaft femur fractures were created in Sprague-Dawley rats, and the animals treated 7 days/week with PTH (10 microg/kg) or a vehicle solution. Each animal also had one fracture treated for 20 min/day with active-LIPUS (spatial-averaged, temporal-averaged intensity [I(SATA)]=100 mW/cm(2)) and the contralateral fracture treated with inactive-LIPUS (placebo). Femurs were harvested 35 days following injury to permit micro-computed tomography, mechanical property and histological assessments of the fracture calluses. There were no interactions between PTH and LIPUS indicating that their effects were additive rather than synergistic. These additive effects were contrasting with LIPUS primarily increasing total callus volume (TV) without influencing bone mineral content (BMC), and PTH having the opposite effect of increasing BMC without influencing TV. As a consequence of the effect of LIPUS on TV but not BMC, it decreased volumetric bone mineral density (vBMD) resulting in a less mature callus. The decreased maturity and persistence of cartilage at the fracture site when harvested offset any beneficial mechanical effects of the increased callus size with LIPUS. In contrast, the effect of PTH on callus BMC but not TV resulted in increased callus vBMD and a more mature callus. This resulted in PTH increasing fracture site mechanical strength and stiffness. These data suggest that PTH may have utility in the treatment of acute bone fractures, whereas LIPUS at an I(SATA) of 100 mW/cm(2) does not appear to be indicated in the management of closed, diaphyseal fractures.

Ultra-som terapêutico e imobilização na reparação do trauma muscular

INTRODUÇÃO: Avaliamos os efeitos do ultra-som terapêutico (UST), adicionado ou não à imobilização gessada (IG), como forma de tratamento à lesão muscular por impacto analisando as propriedades mecânicas de alongamento e carga nos limites de proporcionalidade e máximo, rigidez (R) e resiliência do músculo gastrocnêmio. METODOLOGIA: Utilizamos 70 ratas divididas em 7 grupos:Grupo 1-Controle;Grupo 2-Sem tratamento,Grupo 3-IG por 24 horas;Grupo 4-IG por 72 horas; Grupo 5-UST sem presença de IG;Grupo 6-IG por 24 horas associada ao UST;Grupo 7-IG por 72 horas associada ao UST. RESULTADOS: As propriedades de carga no limite de proporcionalidade e carga máxima mostraram que o grupo estimulado com o UST comportou-se de modo semelhante ao grupo controle. A propriedade de alongamento no limite de proporcionalidade não diferenciou os grupos; o alongamento máximo do grupo estimulado com (UST) e dos grupos imobilizados por 72 horas foram comparáveis ao grupo controle. CONCLUSÃO: O grupo estimulado (UST) apresentou rigidez similar ao grupo controle e resiliência superior a todos os grupos. A utilização isolada do UST forneceu resultados similares àqueles considerados como normais, o mesmo não sendo observado quando o UST foi associado à IG.

Low-intensity pulsed ultrasound (LIPUS) in fresh clavicle fractures: a multi-centre double blind randomised controlled trial

BACKGROUND

Several randomised trials have been published on the effect of low-intensity pulsed ultrasound (LIPUS) on fracture healing in both distal radius and tibia fractures. Most studies showed a positive effect on time to clinical and radiological healing. We hypothesised that LIPUS has a beneficial effect on the healing of fresh clavicle fractures as well and studied its effect in non-operatively treated shaft fractures.

METHODS

We conducted a randomised double blind, placebo-controlled multi-centre trial in 101 adult patients with a non-operatively treated fresh clavicle shaft fracture. Of these patients, 49 used a placebo transducer and 52 patients had an active transducer with ultrasound stimulation (Exogen 2000). Data were analysed on intention to treat basis. Baseline parameters of both groups were not significantly different.

RESULTS

There were no differences in time to subjective clinical fracture healing, resumption of daily activities, sports or professional work, Visual Analogue pain Scores (VAS) and use of pain medication.

CONCLUSION

Our findings did not confirm that LIPUS accelerates clinical healing time of fresh clavicle shaft fractures.

LEVEL OF EVIDENCE

Level 1 evidence that low-intensity pulsed ultrasound does not accelerate clinical fracture healing in non-operatively treated fresh midshaft clavicle fractures.

High-intensity focused ultrasound ablation of ex vivo bovine achilles tendon

Small tears in tendons are a common occurrence in athletes and others involved in strenuous physical activity. Natural healing in damaged tendons can result in disordered regrowth of the underlying collagen matrix of the tendon. These disordered regions are weaker than surrounding ordered regions of normal tendon and are prone to re-injury. Multiple cycles of injury and repair can lead to chronic tendinosis. Current treatment options either are invasive or are relatively ineffective in tendinosis without calcifications. High-intensity focused ultrasound (HIFU) has the potential to treat tendinosis noninvasively. HIFU ablation of tendons is based on a currently-used surgical analog, viz., needle tenotomy. This study tested the ability of HIFU beams to ablate bovine tendons ex vivo. Two ex vivo animal models were employed: a bare bovine Achilles tendon (deep digital flexor) on an acoustically absorbent rubber pad, and a layered model (chicken breast proximal, bovine Achilles tendon central and a glass plate distal to the transducer). The bare-tendon model enables examination of lesion formation under simple, ideal conditions; the layered model enables detection of possible damage to intervening soft tissue and consideration of the possibly confounding effects of distal bone. In both models, the tissues were degassed in normal phosphate-buffered saline. The bare tendon was brought to 23 degrees C or 37 degrees C before insonification; the layered model was brought to 37 degrees C before insonification. The annular array therapy transducer had an outer diameter of 33 mm, a focal length of 35 mm and a 14-mm diameter central hole to admit a confocal diagnostic transducer. The therapy transducer was excited with a continuous sinusoidal wave at 5.25 MHz to produce nominal in situ intensities from 0.23-2.6 kW/cm(2). Insonification times varied from 2-10 s. The focus was set over the range from the proximal tendon surface to 7 mm deep. The angle of incidence ranged from 0 degrees (normal to the tissue surface) to 15 degrees . After insonification, tendons were dissected and photographed, and the dimensions of the lesions were measured. Transmission electron micrographs were obtained from treated and untreated tissue regions. Insonification produced lesions that mimicked the shape of the focal region. When lesions were produced below the proximal tendon surface, no apparent damage to overlying soft tissue was apparent. The low intensities and short durations required for consistent lesion formation, and the relative insensitivity of ablation to small variations in the angle of incidence, highlight the potential of HIFU as a noninvasive treatment option for chronic tendinosis.

Effect of ultrasound therapy on the repair of gastrocnemius muscle injury in rats

The aim of this study was to evaluate the effect of the pulsed ultrasound therapy (PUT) in stimulating myoregeneration and collagen deposition in an experimental model of lacerative gastrocnemius muscle lesion in 30 Wistar rats. Fifteen rats were treated (TG) daily with 1 MHz pulsed ultrasound (50%) at 0.57 W/cm(2) for 5 min, and 15 were control animals (CG). Muscle samples were analyzed on postoperative days 4, 7 and 14 through H&E, Picrosirius-polarization and immunohistochemistry for desmin. The lesions presented similar inflammatory responses in both treated and control groups. The areal fraction of fibrillar collagen was larger in the TG at 4 days post-operatively (17.53+/-6.2% vs 6.79+/-1.3%, p=0.0491), 7 days (31.07+/-7.45% vs 12.57+/-3.6%, p=0.0021) and 14 days (30.39+/-7.3% vs 19.13+/-3.51%, p=0.0118); the areal fraction of myoblasts and myotubes was larger in the TG at 14 days after surgery (41.66+/-2.97% vs 34.83+/-3.08%, p=0.025). Our data suggest that the PUT increases the differentiation of muscular lineage cells, what would favor tissue regeneration. On the other hand, it is also suggested that there is a larger deposition of collagenous fibers, what could mean worse functional performance. However, the percentage of fibers seems to have stabilized at day 7 in TG and kept increasing in CG. Furthermore, the collagen supramolecular organization achieved by the TG is also significant according to the Sirius red staining results.

A survey of therapeutic ultrasound use by physical therapists who are orthopaedic certified specialists

BACKGROUND AND PURPOSE

For many years, ultrasound (US) has been a widely used and well-accepted physical therapy modality for the management of musculoskeletal conditions. However, there is a lack of scientific evidence on its effectiveness. This study examined the opinions of physical therapists with advanced competency in orthopedics about the use and perceived clinical importance of US in managing commonly encountered orthopedic impairments.

SUBJECTS

Four hundred fifty-seven physical therapists who were orthopaedic certified specialists from the Northeast/Mid-Atlantic regions of the United States were invited to participate.

METHODS

A 77-item survey instrument was developed. After face and content validity were established, the survey instrument was mailed to all subjects. Two hundred seven usable survey questionnaires were returned (response rate=45.3%).

RESULTS

According to the surveys, the respondents indicated that they were likely to use US to decrease soft tissue inflammation (eg, tendinitis, bursitis) (83.6% of the respondents), increase tissue extensibility (70.9%), enhance scar tissue remodeling (68.8%), increase soft tissue healing (52.5%), decrease pain (49.3%), and decrease soft tissue swelling (eg, edema, joint effusion) (35.1%). The respondents used US to deliver medication (phonophoresis) for soft tissue inflammation (54.1%), pain management (22.2%), and soft tissue swelling (19.8%). The study provides summary data of the most frequently chosen machine parameters for duty cycle, intensity, and frequency.

DISCUSSION AND CONCLUSION

Ultrasound continues to be a popular adjunctive modality in orthopedic physical therapy. These findings may help researchers prioritize needs for future research on the clinical effectiveness of US.

A preliminary study into the effect of low-intensity pulsed ultrasound on chronic maxillary and frontal sinusitis

Sinusitis is a very common acute or chronic illness that affects a significant percentage of individuals. Recently, therapeutic ultrasound was reported as a treatment for chronic sinusitis. The purpose of this study was twofold: 1) to evaluate the effectiveness of low-intensity pulsed ultrasound (US) in chronic sinusitis using a pretest-posttest research design and 2) to determine the level of association between the independent variables of initial presence of symptoms, age, gender, and duration of disease and the dependent variable of improvement of symptoms. Patients with chronic sinusitis were treated with low-intensity pulsed US, 3 days per week for 15 sessions. Fifty-seven patients (18 females and 39 males; mean age, 35 years) were included in the study. The results of the McNemar test showed a significant change in proportions of post nasal drip and nasal obstruction, two common leading symptoms of patients with chronic sinusitis (p < 0.001). Most of the major and minor symptoms showed significant changes after US therapy (p < 0.05). The total improvement of symptoms was 81.3%. The greatest improvement in symptoms was observed in nasal discharge (100%), followed by facial pain (95.4%) and postnasal drip (82.7%), three major factors in sinusitis. There was a significant, low association between the initial presence of symptoms and the improvement of symptoms after US therapy (chi(2) = 30.352; df = 12; p = 0.002; phi value = 0.356). A significant, low association was also noted between the age and the improvement of symptoms after intervention (chi(2) = 17.548; df = 6; p = 0.007; phi value = 0.270). It may be concluded that low-intensity pulsed US has a significant effect on chronic sinusitis and improves patient symptoms in our study group.

Therapeutic ultrasound: the effects upon cutaneous blood flow in humans

The premise of the current crossover, randomised, double-blinded and controlled study was to ascertain the physiologic effects of pulsed and continuous ultrasound (US) upon cutaneous blood flow in humans as measured by laser Doppler flowmetry. Ten healthy volunteers (5 male, 5 female; aged 18 to 36 y) were assigned to undergo four experimental conditions in a predetermined random order: (i) control, (ii) placebo, (iii) pulsed US and (iv) continuous US. US was applied at a frequency of 3 MHz at an intensity of 1 W/cm(2) for a total of 6 min over the lateral aspect of the forearm. Ambient and skin temperatures were measured concomitantly. Statistical analysis indicated that there were significant differences in blood perfusion units between pulsed US and continuous application of US compared with the control condition for cutaneous blood flow at 2 min (p < or = 0.05), 4 min (p < or = 0.03) and 6 min (p < or = 0.05). Additionally, the placebo group was found only significantly to be different from the control condition at 6 min (p = 0.02), indicating that the movement of the transducer head can produce an additional massage effect. There were no significant differences found for ambient or skin temperature recordings. These findings suggest that active US produces significant increases in cutaneous blood flow.

Ultrasound Produced by a Conventional Therapeutic Ultrasound Unit Accelerates Fracture Repair

Background and Purpose. A recent novel application of ultrasound therapy is the treatment of bone fractures. The aim of this study was to investigate the effect on fracture repair of ultrasound produced by a conventional therapeutic ultrasound unit as used by physical therapists. Subjects and Methods. Bilateral midshaft femur fractures were created in 30 adult male Long-Evans rats. Ultrasound therapy was commenced on the first day after fracture and introduced 5 days a week for 20 minutes a day. Each animal was treated unilaterally with active ultrasound and contralaterally with inactive ultrasound. Active ultrasound involved a 2-millisecond burst of 1.0-MHz sine waves repeating at 100 Hz. The spatially averaged, temporally averaged intensity was set at 0.1 W/cm2. Animals were killed at 25 and 40 days after fracture induction, and the fractures were assessed for bone mass and strength. Results. There were no differences between fractures treated with active ultrasound and fractures treated with inactive ultrasound at 25 days. However, at 40 days, active ultrasound-treated fractures had 16.9% greater bone mineral content at the fracture site than inactive ultrasound-treated fractures. This change resulted in a 25.8% increase in bone size, as opposed to an increase in bone density, and contributed to active ultrasound-treated fractures having 81.3% greater mechanical strength than inactive ultrasound-treated fractures. Discussion and Conclusion. These data indicate that ultrasound produced by a conventional therapeutic ultrasound unit as traditionally used by physical therapists may be used to facilitate fracture repair. However, careful interpretation of this controlled laboratory study is warranted until its findings are confirmed by clinical trials. [Warden SJ, Fuchs RK, Kessler CK, et al. Ultrasound produced by a conventional therapeutic ultrasound unit accelerates fracture repair. Phys Ther. 2006;86:1118–1127.]

Low-intensity pulsed ultrasound accelerates and a nonsteroidal anti-inflammatory drug delays knee ligament healing

BACKGROUND

Low-intensity pulsed ultrasound and nonsteroidal anti-inflammatory drugs are used to treat ligament injuries; however, their individual and combined effects are not established.

HYPOTHESES

Low-intensity pulsed ultrasound accelerates ligament healing, a nonsteroidal anti-inflammatory drug delays healing, and the nonsteroidal anti-inflammatory drug inhibits the beneficial effect of low-intensity pulsed ultrasound.

STUDY DESIGN

Controlled laboratory study.

METHODS

Sixty adult rats underwent bilateral transection of their knee medial collateral ligaments. Animals were divided into 2 drug groups and treated 5 d/wk with celecoxib (5 mg/kg) mixed in a vehicle solution (NSAID group) or vehicle alone (VEH group). One to 3 hours after drug administration, all animals were treated with unilateral active low-intensity pulsed ultrasound and contralateral inactive low-intensity pulsed ultrasound. Equal numbers of animals from each drug group were mechanically tested at 2 weeks (n = 14/group), 4 weeks (n = 8/group), and 12 weeks (n = 8/group) after injury.

RESULTS

Ultrasound and drug intervention did not interact to influence ligament mechanical properties at any time point. After 2 weeks of intervention, ligaments treated with active low-intensity pulsed ultrasound were 34.2% stronger, 27.0% stiffer, and could absorb 54.4% more energy before failure than could ligaments treated with inactive low-intensity pulsed ultrasound, whereas ligaments from the NSAID group could absorb 33.3% less energy than could ligaments from the VEH group. There were no ultrasound or drug effects after 4 and 12 weeks of intervention.

CONCLUSIONS

Low-intensity pulsed ultrasound accelerated but did not improve ligament healing, whereas the nonsteroidal anti-inflammatory drug delayed but did not impair healing. When used in combination, the beneficial low-intensity pulsed ultrasound effect was cancelled by the detrimental nonsteroidal anti-inflammatory drug effect.

CLINICAL RELEVANCE

Low-intensity pulsed ultrasound after ligament injury may facilitate earlier return to activity, whereas non-steroidal anti-inflammatory drugs may elevate early reinjury risk.

Intradiscal thermal therapy does not stimulate biologic remodeling in an in vivo sheep model

STUDY DESIGN

Thermal energy was delivered in vivo to ovine cervical discs and the postheating response was monitored over time.

OBJECTIVES

To determine the effects of two distinctly different thermal exposures on biologic remodeling: a "high-dose" regimen intended to produce both cellular necrosis and collagen denaturation and a "low-dose" regimen intended only to kill cells.

SUMMARY OF BACKGROUND DATA

Thermal therapy is a minimally invasive technique that may ameliorate discogenic back pain. Potential therapeutic mechanisms include shrinkage of collagenous tissues, stimulation of biologic remodeling, and ablation of cytokine-producing cells and nociceptive fibers.

METHODS

Intradiscal heating was performed using directional interstitial ultrasound applicators. Temperature and thermal dose distributions were characterized. The effects of high (>70 C, 10 minutes) and low (52 C-54 C, 10 minutes) temperature treatments on chronic biomechanical and architectural changes were compared with sham-treated and control discs at 7, 45, and 180 days.

RESULTS

The high-dose treatment caused both an acute and chronic loss of proteoglycan staining and a degradation of biomechanical properties compared with low-dose and sham groups. Similar amounts of degradation were observed in the low-dose and sham-treated discs relative to the control discs at 180 days after treatment.

CONCLUSIONS

While a high temperature thermal protocol had a detrimental effect on the disc, the effects of low temperature treatment were relatively minor. Thermal therapy did not stimulate significant biologic remodeling. Future studies should focus on the effects of low-dose therapy on tissue innervation and pro-inflammatory factor production.

The effects of therapeutic ultrasound on heart rate variability: a placebo controlled trial

The effect of therapeutic ultrasound (US) on nervous system is controversial and the effect on autonomic nervous system is not clear. Therefore, the present placebo-controlled trial was planned to investigate the effects of therapeutic US application on right-side stellate ganglion, by using analysis of heart rate variability (HRV). A total 12 healthy volunteers were included in the study. RR intervals were recorded for 5 min before and after the US application, in supine and sitting positions. All procedures were repeated in all participants with sham US one week later. The heart rate (HR) was obtained by time-domain analysis and low frequency (LF) power (%), high frequency (HF) power (%) and LF/HF ratio values were obtained by frequency-domain (power spectral density) analysis. After the US application, there was a decrease in the HR (p = 0.002) and the HF power (%) component (p = 0.015) in supine position and a decrease in HR (p = 0.002) and LF/HF ratio (p = 0.028) in sitting position. There was no significant difference after the sham US application. In conclusion, we observed that therapeutic US application on stellate ganglion causes alterations on HRV parameters.

Comparative study of the efficacy of the topical application of hydrocortisone, therapeutic ultrasound and phonophoresis on the tissue repair process in rat tendons

The purpose of this study was to compare the treatment efficacy of topical application of hydrocortisone, therapeutic ultrasound (US) and phonophoresis on the rat's Achilles tendon (tendo calcaneus) repair process after tenotomy. The two treated groups with US were made in a pulsed mode. The irradiation of US was performed at a frequency of 1 MHz and an intensity of 0.5 W/cm2 (SATA), for 5 min each session. The tendons were analyzed using the polarized light microscopy. The results showed that the treated group with the topical application of hydrocortisone has not been delivered transdermally and that the molecule of collagen responds to the ultrasonic stimulation. The treatment with phonophoresis was the more efficient method. These findings allow us to conclude that the US stimulates the acceleration of tissue repair processes and induces the transdermal delivery of hydrocortisone in a therapeutic concentration on the tendon.

A new direction for ultrasound therapy in sports medicine

Ultrasound therapy is a widely available and frequently used electrophysical agent in sports medicine. However, systematic reviews and meta-analyses have repeatedly concluded that there is insufficient evidence to support a beneficial effect of ultrasound at dosages currently being introduced clinically. Consequently, the role of ultrasound in sports medicine is in question. This does not mean that ultrasound should be discarded as a therapeutic modality. However, it does mean that we may need to look in a new direction to explore potential benefits. A new direction for ultrasound therapy has been revealed by recent research demonstrating a beneficial effect of ultrasound on injured bone. During fresh fracture repair, ultrasound reduced healing times by between 30 and 38%. When applied to non-united fractures, it stimulated union in 86% of cases. These benefits were generated using low-intensity (<0.1 W/cm(2)) pulsed ultrasound (LIPUS), a dose alternative to that traditionally used in sports medicine. Although currently developed for the intervention of bone injuries, LIPUS has the potential to be used on tissues and conditions more commonly encountered in sports medicine. These include injuries to ligament, tendon, muscle and cartilage. This review discusses the effect of LIPUS on bone fractures, the dosages introduced and the postulated mechanisms of action. It concludes by discussing the relevance of these latest findings to sports medicine and how this evidence of a beneficial clinical effect may be implemented to intervene in sporting injuries to bone and other tissues. The aim of the paper is to highlight this latest direction in ultrasound therapy and stimulate new lines of research into the efficacy of ultrasound in sports medicine. In time this may lead to accelerated recovery from injury and subsequent earlier return to activity.