Therapeutic ultrasound: the effects upon cutaneous blood flow in humans

Short-Term Thermal Effect of Continuous Ultrasound from 3 MHz to 1 and 0.5 W/cm2 Applied to Gastrocnemius Muscle

Continuous ultrasound is recognized for its thermal effect and use in the tissue repair process. However, there is controversy about its dosage and efficacy. This study used infrared thermography, a non-invasive technique, to measure the short-term thermal effect of 3 MHz continuous ultrasound vs. a placebo, referencing the intensity applied. It was a single-blind, randomized clinical trial of 60 healthy volunteers (19-24 years old) divided into three equal groups. Group 1:1 W/cm2 for 5 min; Group 2: 0.5 W/cm2 for 10 min; and Group 3: the placebo for 5 min. The temperature was recorded through five thermographic images per patient: pre- and post-application, 5, 10, and 15 min later. After statistical analysis, a more significant decrease in temperature (p<0.05 ) was observed in the placebo group compared with the remaining groups after the application of continuous ultrasound. Group 1 was the one that generated the highest significant thermal effect (p<0.001), with an increase of 3.05 °C at 15 min, compared with the other two groups. It is concluded that to generate a thermal effect in the muscle, intensities of ≥1 W/cm2 are required, since the dosage maintained a temperature increase for more than 5 min.

Analgesic Effect of Extracorporeal Shock-Wave Therapy in Individuals with Lateral Epicondylitis: A Randomized Controlled Trial

This study was conducted to investigate the effect of extracorporeal shock-wave therapy (ESWT) on pain, grip strength, and upper-extremity function in lateral epicondylitis. A sample of 40 patients with LE (21 males) was randomly allocated to either the ESWT experimental (n = 20) or the conventional-physiotherapy control group (n = 20). All patients received five sessions during the treatment program. The outcome measures used were the Visual Analog Scale (VAS), the Taiwan version of the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire, and a dynamometer (maximal grip strength). Forty participants completed the study. Participants in both groups improved significantly after treatment in terms of VAS (pain reduced), maximal grip strength, and DASH scores. However, the pain was reduced and upper-extremity function and maximal grip strength were more significantly improved after ESWT in the experimental group. ESWT has a superior effect in reducing pain and improving upper-extremity function and grip strength in people with lateral epicondylitis. It seems that five sessions of ESWT are optimal to produce a significant difference. Further studies are strongly needed to verify our findings.

Hypotension and Bradycardia Produced by Transthoracic Application of Low-Intensity Ultrasound Therapy in Hearts of Healthy Rats - A Preclinical Study

Objective

To investigate the cardiovascular effects produced by transthoracic application of low-intensity pulsed ultrasound therapy (LIPUST).

Methods

Three-month-old male Wistar rats (± 300 g, N=16) were randomly allocated in two groups, namely SHAM (control group, faked procedures) and UST (animals treated with LIPUST). These animals, under anesthesia, were instrumented (femoral artery and vein catheterization) for hemodynamic recordings (mean blood pressure [MBP], heart rate [HR]) and blood biochemical profile (lipids, creatine kinase-myocardial band [CK-MB]). Then, LIPUST (spatial average-temporal average [ISATA] 1-MHz, power 0.1 to 1.2 W/cm2, pulsed 2:8 ms, cycle at 30%, for three minutes) was applied to animals from the UST group, externally to their thorax. SHAM animals were equally manipulated, but without application of ultrasound energy. After the hemodynamic and biochemical measurements, animals were sacrificed, and their hearts were mounted in a Langendorff apparatus for coronary reactivity evaluation. Standard histology techniques were employed to analyze the hearts.

Results

LIPUST application caused statistically significant reductions in MBP (92±4 vs. 106±1 mmHg) and HR (345±14 vs. 380±17 rpm) when compared with SHAM procedures. UST rats exhibited higher CK-MB levels (318±55 vs. 198±26 U/dL) and lower plasma triglycerides levels (38±7 vs. 70±10 mg/dL) than SHAM animals. Coronary reactivity was not significantly changed by LIPUST. Cardiac histopathology showed an increase in capillary permeability in treated animals when compared with SHAM animals.

Conclusion

Noninvasive LIPUST induces significant metabolic and hemodynamic changes, including intensity-dependent bradycardia and hypotension, indicating a possible therapeutic effect for cardiac events.

Local anesthesia enhanced with increasing high-frequency ultrasound intensity

The effect of local anesthetics, particularly those which are hydrophilic, such as tetrodotoxin, is impeded by tissue barriers that restrict access to individual nerve cells. Methods of enhancing penetration of tetrodotoxin into nerve include co-administration with chemical permeation enhancers, nanoencapsulation, and insonation with very low acoustic intensity ultrasound and microbubbles. In this study, we examined the effect of acoustic intensity on nerve block by tetrodotoxin and compared it to the effect on nerve block by bupivacaine, a more hydrophobic local anesthetic. Anesthetics were applied in peripheral nerve blockade in adult Sprague-Dawley rats. Insonation with 1-MHz ultrasound at acoustic intensity greater than 0.5 W/cm² improved nerve block effectiveness, increased nerve block reliability, and prolonged both sensory and motor nerve blockade mediated by the hydrophilic ultra-potent local anesthetic, tetrodotoxin. These effects were not enhanced by microbubbles. There was minimal or no tissue injury from ultrasound treatment. Insonation did not enhance nerve block from bupivacaine. Using an in vivo model system of local anesthetic delivery, we studied the effect of acoustic intensity on insonation-mediated drug delivery of local anesthetics to the peripheral nerve. We found that insonation alone (at intensities greater than 0.5 W/cm²) enhanced nerve blockade mediated by the hydrophilic ultra-potent local anesthetic, tetrodotoxin. Graphical abstract.

Effects of Ultrasound-Assisted Preconditioning on Critically Ischemic Skin Flaps: An Experimental Study

This study evaluates the effect of ultrasound-assisted preconditioning on critically ischemic flaps. Ninety-eight Sprague Dawley rats were randomly divided into eight groups. Control, surgical delay, ultrasound and sham groups were designed. Modified McFarlane flaps were raised on the back of rats, and flap survival rate was assessed on post-operative day 14 in control, ultrasound and sham groups. Bipedicled flaps were created in the surgical delay group, and 14 d after delaying, all skin flaps were elevated. Statistically, flap survival rates of all ultrasound groups were significantly higher than the control group. Plasma vascular endothelial growth factor levels were increased in all ultrasound groups. Vessel counts did not show any difference between the groups. This study shows that the preconditioning by ultrasound can be used to improve the viability of ischemic skin flaps almost at a level close to the surgical delay.

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.

Effect of a Controlled Release of Epinephrine Hydrochloride from PLGA Microchamber Array: In Vivo Studies

This paper presents the synthesis of highly biocompatible and biodegradable poly(lactide- co-glycolide) (PLGA) microchamber arrays sensitive to low-intensity therapeutic ultrasound (1 MHz, 1-2 W, 1 min). A reliable method was elaborated that allowed the microchambers to be uniformly filled with epinephrine hydrochloride (EH), with the possibility of varying the cargo amount. The maximum load of EH was 4.5 μg per array of 5 mm × 5 mm (about 24 pg of EH per single microchamber). A gradual, spontaneous drug release was observed to start on the first day, which is especially important in the treatment of acute patients. Ultrasound triggered a sudden substantial release of EH from the films. In vivo real-time studies using a laser speckle contrast imaging system demonstrated changes in the hemodynamic parameters as a consequence of EH release under ultrasound exposure. We recorded a decrease in blood flow as a vascular response to EH release from a PLGA microchamber array implanted subcutaneously in a mouse. This response was immediate and delayed (1 and 2 days after the implantation of the array). The PLGA microchamber array is a new, promising drug depot implantable system that is sensitive to external stimuli.

Survey of ultrasound practice amongst podiatrists in the UK

Background

Ultrasound in podiatry practice encompasses musculoskeletal ultrasound imaging, vascular hand-held Doppler ultrasound and therapeutic ultrasound. Sonography practice is not regulated by the Health and Care Professions Council (HCPC), with no requirement to hold a formal qualification. The College of Podiatry does not currently define ultrasound training and competencies.

This study aimed to determine the current use of ultrasound, training received and mentorship received and/or provided by podiatrists using ultrasound.

Methods

A quantitative study utilising a cross-sectional, on-line, single-event survey was undertaken within the UK.

Results

Completed surveys were received from 284 podiatrists; 173 (70%) use ultrasound as part of their general practice, 139 (49%) for musculoskeletal problems, 131 (46%) for vascular assessment and 39 (14%) to support their surgical practice. Almost a quarter (n = 62) worked for more than one organisation; 202 (71%) were employed by the NHS and/or private sector (n = 118, 41%).

Nearly all (93%) respondents report using a hand-held vascular Doppler in their daily practice; 216 (82%) to support decisions regarding treatment options, 102 (39%) to provide diagnostic reports for other health professionals, and 34 (13%) to guide nerve blocks.

Ultrasound imaging was used by 104 (37%) respondents primarily to aid clinical decision making (n = 81) and guide interventions (steroid injections n = 67; nerve blocks n = 39). Ninety-three percent stated they use ultrasound imaging to treat their own patients, while others scan at the request of other podiatrists (n = 28) or health professionals (n = 18). Few use ultrasound imaging for research (n = 7) or education (n = 2).

Only 32 (11%) respondents (n = 20 private sector) use therapeutic ultrasound to treat patients presenting with musculoskeletal complaints, namely tendon pathologies.

Few respondents (18%) had completed formal post-graduate CASE (Consortium for the Accreditation of Sonographic Education) accredited ultrasound courses.

Forty (14%) respondents receive ultrasound mentorship; the majority from fellow podiatrists (n = 17) or medical colleagues (n = 15). Over half (n = 127) who do not have ultrasound mentorship indicated they would like a mentor predominantly for ultrasound imaging. Fifty-five (19%) report they currently provide ultrasound mentorship for others.

Conclusions

Understanding the scope of ultrasound practice, the training undertaken and the requirements for mentorship will underpin the development of competencies and recommendations defined by the College of Podiatry to support professional development and ensure safe practice.

Electronic supplementary material

The online version of this article (10.1186/s13047-018-0263-4) contains supplementary material, which is available to authorized users.

Laser Doppler Flowmetry in Manual Medicine Research

Laser Doppler flowmetry (LDF) is commonly used in combination with reactivity tests to noninvasively evaluate skin sympathetic nerve activity and skin microvascular function. In manual medicine research, LDF has been used as a marker for global peripheral sympathetic nervous system function, but these results should be considered with caution because skin sympathetic nerve activity physiology is often overlooked. Another limitation of LDF in manual medicine research is the processing of LDF recordings. Two methods have been suggested: the time-domain analysis and the frequency-domain analysis. Standardization is required for data collection and processing in either domain to accurately interpret these changes in skin blood flow that occur after manual procedures. For physiologic studies using LDF, the authors recommend the use of noninvasive reactivity tests (positive controls) to evaluate the different mechanisms involved in overall skin blood flow changes and to compare the magnitude of these changes with those specifically elicited by manual procedures. J Am Osteopath Assoc.2014;114(12):908-917 doi:10.7556/jaoa.2014.178

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.

Effects of therapeutic ultrasound on range of motion and stretch pain

[Purpose] This study aimed to clarify the effects of therapeutic ultrasound on range of motion and stretch pain and the relationships between the effects. [Subjects] The subjects were 15 healthy males. [Methods] Subjects performed all three interventions: (1) ultrasound (US group), (2) without powered ultrasound (placebo group), and (3) rest (control group). Ultrasound was applied at 3 MHz with an intensity of 1.0 W/cm(2) and a 100% duty cycle for 10 minutes. The evaluation indices were active and passive range of motion (ROM), stretch pain (visual analog scale; VAS), and skin surface temperature (SST). The experimental protocol lasted a total of 40 minutes; this was comprised of 10 minutes before the intervention, 10 minutes during the intervention (US, placebo, and control), and 20 minutes after the intervention. [Results] ROM and SST were significantly higher in the US group than in the placebo and control groups for the 20 minutes after ultrasound, though there was no change in stretch pain. [Conclusion] The effects of ultrasound on ROM and SST were maintained for 20 minutes after the intervention. The SST increased with ultrasound and decreased afterwards. Additionally, the SST tended to return to baseline levels within 20 minutes after ultrasound exposure. Therefore, these effects were caused by a combination of thermal and mechanical effects of the ultrasound.

Effects of therapeutic ultrasound on intramuscular blood circulation and oxygen dynamics

PURPOSE

This study aimed to clarify the effects of therapeutic ultrasound on intramuscular local blood circulation (and oxygen dynamics) using near-infrared spectroscopy (NIRS).

PARTICIPANTS

The participants were 11 healthy males.

METHODS

All participants performed all three trials; (1) the ultrasound (US group), (2) without powered ultrasound (placebo group), and (3) rest (control group). Ultrasound was applied at 3 MHz, 1.0 W/cm(2), and 100% duty cycle for 10 minutes. Evaluation index were oxygenated, deoxygenated, and total hemoglobin (Hb) concentrations in the intramuscular and skin surface temperature (SST). The experimental protocol was a total of 40 minutes, that is, 10 minutes before trial (rest), 10 minutes during the trial (ultrasound, placebo, and control), and 20 minutes after trial (rest). The NIRS and SST data collected before and after the trial were divided into 5 minutes intervals for further analysis.

RESULTS

Oxygenated and total hemoglobin levels were significantly higher in the US group than in the placebo and control groups for the 20 minutes after ultrasound (p < 0.01). The SST was significantly higher in the US group than in the control for 15 minutes after ultrasound (p < 0.05), while it was significantly lower in the placebo group than in the US and control groups for 20 minutes after the trials (p < 0.01).

CONCLUSION

The effects of ultrasound were maintained for 20 minutes after the trial on intramuscular blood circulation and oxygen dynamics. These effects were caused by a combination of thermal and mechanical effects of the ultrasound.

Pulsed ultrasound therapy accelerates the recovery of skeletal muscle damage induced by Bothrops jararacussu venom

We studied the effect of pulsed ultrasound therapy (UST) and antibothropic polyvalent antivenom (PAV) on the regeneration of mouse extensor digitorum longus muscle following damage by Bothrops jararacussu venom. Animals (Swiss male and female mice weighing 25.0 ± 5.0 g; 5 animals per group) received a perimuscular injection of venom (1 mg/kg) and treatment with UST was started 1 h later (1 min/day, 3 MHz, 0.3 W/cm², pulsed mode). Three and 28 days after injection, muscles were dissected and processed for light microscopy. The venom caused complete degeneration of muscle fibers. UST alone and combined with PAV (1.0 mL/kg) partially protected these fibers, whereas muscles receiving no treatment showed disorganized fascicules and fibers with reduced diameter. Treatment with UST and PAV decreased the effects of the venom on creatine kinase content and motor activity (approximately 75 and 48%, respectively). Sonication of the venom solution immediately before application decreased the in vivo and ex vivo myotoxic activities (approximately 60 and 50%, respectively). The present data show that UST counteracts some effects of B. jararacussu venom, causing structural and functional improvement of the regenerated muscle after venom injury.

[Effects of two methods of heat therapy on the acute vascular response and hemodynamics in healthy subjects]

OBJECTIVE

Recently, non-pharmacological resources to relieve pain like hot packs and ultrasound (US) have become common in clinical practice. However, little experimental evidence is available about the possible mechanisms through which these methods bring about pain relief. We aimed to determine the effects of hot packs and US on the acute vascular response and on hemodynamic parameters in healthy subjects.

MATERIALS AND METHODS

We conducted an experimental study in 20 healthy subjects (10 men and 10 women; mean age, 22.54±1.70 years). The two interventions were randomly applied: a) hot packs (n=10): 15min at 60°C and b) US (n=10): 15min at 1Mhz. Before and after each intervention, the following vascular parameters were measured in the brachial artery using Doppler ultrasonography with a 7MHz probe: arterial compliance, elastic modulus, beta stiffness index, systolic and diastolic arterial diameters, systolic flow velocity and diastolic flow velocity, systolic/diastolic ratio, resistance index, and pulsatility index. The following hemodynamic parameters were monitored: heart rate and blood pressure (systolic, diastolic, and mean).

RESULTS

After the application of hot packs, we observed changes in diastolic flow velocity and in the pulsatility index (P<05). After the application of US, we observed changes in diastolic flow velocity, systolic/diastolic ratio, resistance index, and arterial compliance (P<05). No changes in hemodynamic parameters were observed after either intervention.

CONCLUSIONS

Applying hot packs or US modifies the physiology of the vascular system but does not affect hemodynamic parameters in healthy subjects.

Mechanical stimulation improves survival in random-pattern skin flaps in rats

This was a study on the effects of 3-MHz ultrasound at 16- and 100-Hz pulse repetition frequencies on angiogenesis and viability of random-pattern skin flaps in rats. A cranially-based dorsal skin flap was raised in 60 EPM-Wistar rats, which were randomly divided into four groups: control, sham, 16-Hz and 100-Hz groups. The mean percentage of necrosis was as follows: control, 42% ± 13%; sham, 18% ± 13%; 16-Hz group, 13% ± 10%; and 100-Hz group, 15% ± 7%, with significant differences between the control and the other groups (p < 0.001). The mean vascular density was as follows: control, 5% ± 2%; sham, 7% ± 2%; 16-Hz group, 21% ± 4%; and 100-Hz group, 24% ± 10%, with significant differences between control and ultrasound groups, and between the sham and ultrasound groups (p < 0.001). Both ultrasound treatments (16- and 100-Hz PRFs) induced angiogenesis, and sham and ultrasound treatments improved viability of random-pattern skin flaps in rats.

Ultrasound lipoclasia on subcutaneous adipose tissue to produce acute hyperglycemia and enhance acute inflammatory response in healthy female rats

BACKGROUND

Ultrasound lipoclasia (USL) on white adipose tissue (WAT) has been largely used in the treatment of cellulite. Nevertheless, the acute consequences of this therapy on metabolism and biochemical profile are significant and should be taken into account.

OBJECTIVES

To analyze the acute metabolic effects of USL in WAT of healthy rats using analyses of body composition, biochemical profile, and inflammatory markers.

METHODS

Female Wistar rats weighing approximately 250 g were divided into two groups (n=10 each): control and treated. The treated group was submitted to USL, a single 3-MHz ultrasound application (5.6 W/cm(2)), in gluteal-femoral WAT (3 cm(2)) for 3 minutes. Animals were subjected to glycemic control. Body composition was analyzed using bio-impedance, and lipid profile, insulinemia, C-reactive protein (CRP), and lactate dehydrogenase (LDH) were measured.

RESULTS

USL reduced (p<.05) body fat mass. The basal metabolic rate was found to have increased (p<.05). Basal insulin and the lipoprotein profile were not different, although the glycemic curve and CRP and LDH (p<.05) levels were higher.

CONCLUSIONS

Fat mobilization using USL provokes acute hyperglycemia and enhances an acute inflammatory response, producing cardiometabolic risk in female rats.

Burn rehabilitation and research: proceedings of a consensus summit

Burn rehabilitation is an essential component of successful patient care. In May 2008, a group of burn rehabilitation clinicians met to discuss the status and future needs of burn rehabilitation. Fifteen topic areas pertinent to clinical burn rehabilitation were addressed. Consensus positions and suggested future research directions regarding the physical aspects of burn rehabilitation are shared.

In vivo imaging of blood flow in the mouse Achilles tendon using high-frequency ultrasound

OBJECTIVE

Achilles tendinitis is a common clinical problem with many treatment modalities, including physical therapy, exercise and therapeutic ultrasound. However, evaluating the effects of current therapeutic modalities and studying the therapeutic mechanism(s) in vivo remains problematic. In this study, we attempted to observe the morphology and microcirculation changes in mouse Achilles tendons between pre- and post-treatment using high-frequency (25 MHz) ultrasound imaging. A secondary aim was to assess the potential of high-frequency ultrasound in exploring therapeutic mechanisms in small-animal models in vivo.

METHODS

A collagenase-induced mouse model of Achilles tendinitis was adopted, and 5 min treatment of continuous-mode low-frequency (45 kHz) ultrasound with 47 mW/cm(2) maximum intensity and 16.3 cm(2) effective beam radiating area was applied. The B-mode images showed no focal hypoechoic regions in normal Achilles tendons either pre- or post-treatment. The Doppler power energy and blood flow rate were measured within the peritendinous space of the Achilles tendon.

CONCLUSION

An increase in the microcirculation was observed soon after the low-frequency ultrasound treatment, which was due to immediate induction of vascular dilatation. The results suggest that applying high-frequency Doppler imaging to small-animal models will be an invaluable aid in explorations of the therapeutic mechanism(s). Our future work includes using imaging to assess microcirculation changes in tendinitis between before and after treatment over a long time period, which is expected to yield useful physiological data for future human studies.

Non-viral VEGF(165) gene therapy--magnetofection of acoustically active magnetic lipospheres ('magnetobubbles') increases tissue survival in an oversized skin flap model

Adenoviral transduction of the VEGF gene in an oversized skin flap increases flap survival and perfusion. In this study, we investigated the potential of magnetofection of magnetic lipospheres containing VEGF₁₆₅-cDNA on survival and perfusion of ischemic skin flaps and evaluated the method with respect to the significance of applied magnetic field and ultrasound. We prepared perfluoropropane-filled magnetic lipospheres (‘magnetobubbles’) from Tween60-coated magnetic nanoparticles, Metafectene, soybean-oil and cDNA and studied the effect in an oversized random-pattern-flap model in the rats (n= 46). VEGF-cDNA-magnetobubbles were administered under a magnetic field with simultaneously applied ultrasound, under magnetic field alone and with applied ultrasound alone. Therapy was conducted 7 days pre-operative. Flap survival and necrosis were measured 7 days post-operatively. Flap perfusion, VEGF-protein concentration in target and surrounding tissue, formation and appearance of new vessels were analysed additionally. Magnetofection with VEGF-cDNA-magnetobubbles presented an increased flap survival of 50% and increased flap perfusion (P < 0.05). Without ultrasound and without magnetic field, the effect is weakened. VEGF concentration in target tissue was elevated (P < 0.05), while underlying muscle was not affected. Our results demonstrate the successful VEGF gene therapy by means of magnetobubble magnetofection. Here, the method of magnetofection of magnetic lipospheres is equally efficient as adenoviral transduction, but has a presumable superior safety profile.