***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: AIM : The objective of our study was to determine which ultrasound power density ( 0.5 W/cm2 or 1 W/cm2 ) is more effective at reducing the area and volume of leg ulceration . METHODS : A total of 65 patients with venous ulcers were r and omly divided into three groups : A , B and C. In group A , 22 patients were treated with ultrasound rated at 1 W/cm2 and with compressive therapy . In group B , 21 patients were treated with ultrasound rated at 0.5 W/cm2 and with compressive therapy . In both groups the patients were treated with a pulsed wave of a duty cycle of 1/5 ( impulse time=2 ms , pause time=8 ms ) and frequency of 1 MHz . The 22 patients in group C ( control group ) were subjected to topical pharmacological treatment . RESULTS : We found a statistically significant reduction of the ulcer area , volume and linear dimensions in all three groups of patients . The ulcer area reduction rate was highest in group B. The volume reduction rate in group B was higher than in group A only . The rate of reduction of suppurate area was highest in group B. CONCLUSION : We have demonstrated that ultrasound rated at 0.5 W/cm2 causes greater and faster changes in the healing process than ultrasound rated at 1 W/cm2 In a defined Swedish population of 270 800 , all patients with current chronic leg ulcers ( 827 ) were identified and a r and om sample of 382 studied in detail . Ulcers of primarily venous cause comprised 54 per cent of the total , giving a point prevalence of 0–16 per cent ( 95 per cent confidence interval 0–15‐0‐18 per cent ) . Half of all patients experienced their first ulcer episode before the age of 65 years , a greater proportion ( 61 per cent , P<0.0001 ) in the subgroup with venous ulcers . The median duration of ulcer diathesis was significantly longer in patients with venous than in those with non‐venous lesions ( 13‐4 versus 2–5 years , P < 0.001 ) . About half the patients with venous and non‐venous ulcers had had their current lesion for longer than 1 year . Venous ulcers were more often recurrent than those of non‐venous type ( 72 versus 45 per cent of patients , P<0.0001 ) . Patients with venous ulcers had a significantly higher body mass index ( P<0.001 ) . The number of dressing changes performed per week was 1100 per 100000 population . The predictive value of ‘ classical ’ clinical indicators of venous ulcer did not exceed 0–76 . To increase the accuracy of diagnosis of venous ulcer , clinical examination should be combined with non‐invasive ‘ objective ’ haemodynamic assessment of the venous circulation A nurse-led multicentre r and omised controlled trial will compare the clinical effectiveness of weekly ultrasound combined with st and ard care in the treatment of  ' hard-to-heal ' venous leg ulcers .  Recruitment started last autumn ' Hard-to-heal ' wounds are those which fail to heal with st and ard therapy in an orderly and timely manner and may warrant the use of advanced treatments such as non-contact low-frequency ultrasound ( NLFU ) therapy . This evaluator-blinded , single-site , r and omised controlled trial , compared NLFU in addition to UK st and ard of care [ SOC : ( NLFU + SOC ) ] three times a week , with SOC alone at least once a week . Patients with chronic venous leg ulcers were eligible to participate . All 36 r and omised patients completed treatment ( 17 NLFU + SOC , 19 SOC )  , and baseline demographics were comparable between groups . NLFU + SOC patients showed a -47 % ( SD : 38 % ) change in wound area ; SOC , -39 % ( 38 % ) change ; and difference , -7·4 % [ 95 % confidence intervals ( CIs ) -33·4 - 18·6 ; P = 0·565 ] . The median number of infections per patient was two in both arms of the study and change in quality of life ( QoL ) scores was not significant ( P = 0·490 ) . NLFU + SOC patients reported a substantial mean ( SD ) reduction in pain score of -14·4 ( 14·9 ) points , SOC patients ' pain scores reduced by -5·3 ( 14·8 ) ; the difference was -9·1 ( P = 0·078 ) . Results demonstrated the importance of high- quality wound care . Outcome measures favoured NLFU + SOC over  SOC , but the differences were not statistically significant . A larger sample size and longer follow-up may reveal NLFU-related improvements not identified in this study A controlled study of the effects of ultrasound on healing chronic leg ulcers  was carried out in conjunction with st and ard treatment on 38 patients divided r and omly into two groups . All patients received st and ard treatment ( paste impregnated b and age and a self-adhesive elastic b and age plus placebo ultrasound or ultrasound ( 1.0 watt/cm2 at 1 MHz , for 10 min ) twice weekly for 8 weeks . Percentage healed ulcer area and number of healed ulcers were compared after 2 , 4 , 6 and 8 weeks . There were no significant differences in the proportion of healed ulcers or ulcer area in the ultrasound group as compared with the placebo group BACKGROUND AND PURPOSE Nosocomial infections present a widespread problem in today 's healthcare environment , with a significant number of patients acquiring an infection annually . With the contemporary transition of immunocompromised and high-risk patients to community-based care , therapeutic ultrasound has the potential to be a vector of infection in the physiotherapy setting . The purpose of the present study was to determine the degree of contamination on therapeutic ultrasound transducer heads and ultrasound gel after routine clinical use , and to evaluate the efficacy of recommended infection control procedures . METHOD The study consisted of two phases . Using a prospect i ve cross-sectional design , microbiological cultures were obtained from 44 transducer heads and 43 gels . Subjects were drawn from a variety of physiotherapy practice setting s. All sample s containing more than five colony forming units per cm2 were considered contaminated . Following these measurements , a repeated- measures design was used to re-evaluate the 44 transducer heads for the amount and type of bacteria present after cleaning with a 70 % alcohol wipe . RESULTS Twenty-seven per cent of transducer heads and 28 % of gels were contaminated . Transducer heads showed fairly low levels of contamination across the sample , with the majority of organisms isolated found in normal skin and environmental flora . Gels were heavily contaminated with opportunistic and potentially pathogenic organisms , including Stenotrophomonas maltophilia , Staphylococcus aureus , Acinetobacter baumannii and Rhodotorula mucilaginosa . No multi-resistant organisms were identified . Cleaning with 70 % alcohol significantly reduced the level of contamination on transducer heads ( p < 0.01 ) . CONCLUSIONS Therapeutic ultrasound equipment is a potential vector for nosocomial infection in physiotherapy patients . The risk of infection from transducer heads can be effectively removed by cleaning with 70 % alcohol between patients . Further research into possible strategies to reduce the risk of infection from ultrasound gels is needed In a controlled trial to ascertain whether ultrasound given weekly in conjunction with a st and ard treatment for  chronic leg ulcers  improves the rate of healing  56 patients were r and omised to st and ard treatment ( paste impregnated b and age and a self-adhesive elastic b and age )  and 52 to st and ard treatment plus pulsed ultrasound given weekly . After 12 weeks the proportion of ulcers healed was 20 % greater in the ultrasound than in the control group BACKGROUND A feasibility study was conducted to characterize the effects of noncontact low-frequency ultrasound therapy for  chronic , recalcitrant lower-leg and foot ulcerations .  METHODS The study was an open-label , nonr and omized , baseline-controlled clinical case series . Patients were initially treated with the Mayo Clinic st and ard of care before the addition of or the switch to noncontact low-frequency ultrasound therapy . We analyzed the medical records of 51 patients ( median + /- SD age , 72 + /- 15 years ) with one or more of the following conditions : diabetes mellitus , neuropathy , limb ischemia , chronic renal insufficiency , venous disease , and inflammatory connective tissue disease . All of the patients had lower-extremity ulcers , 20 % had a history of amputation , and 65 % had diabetes . Of all the wounds , 63 % had a multifactorial etiology , and 65 % had associated transcutaneous oximetry levels below 30 mm Hg . RESULTS The mean + /- SD treatment time of wounds during the baseline st and ard of care control period versus the noncontact low-frequency ultrasound therapy period was 9.8 + /- 5.5 weeks versus 5.5 + /- 2.8 weeks ( P < .0001 ) . Initial and end measurements were recorded , and percent volume reduction of the wound was calculated . The mean + /- SD percent volume reduction in the baseline st and ard of care control period versus the noncontact low-frequency ultrasound therapy period was 37.3 % + /- 18.6 % versus 94.9 % + /- 9.8 % ( P < .0001 ) . CONCLUSIONS Using noncontact low-frequency ultrasound improved the rate of healing and closure in recalcitrant lower-extremity ulcerations BACKGROUND Drawbacks exist with the st and ard treatment ( four-layer compression b and ages ) for venous leg ulcers . We have therefore compared the clinical effectiveness and cost-effectiveness of two-layer compression hosiery with the four-layer b and age for the treatment of such ulcers . METHODS We undertook this pragmatic , open , r and omised controlled trial with two parallel groups in 34 centres in Engl and and Northern Irel and . The centres were community nurse teams or services , family doctor practice s , leg ulcer clinics , tissue viability clinics or services , and wound clinics . Participants were aged 18 years or older with a venous leg ulcer and an ankle brachial pressure index of at least 0·8 , and were tolerant of high compression . We r and omly allocated participants ( 1:1 ) to receive two-layer compression hosiery or a four-layer b and age , using a remote r and omisation service and prevali date d computer r and omisation program . Participants were stratified by ulcer duration and ulcer area with permuted blocks ( block sizes four and six ) . The primary endpoint was time to ulcer healing , with a maximum follow-up of 12 months . Although participants and health-care providers were not masked to treatment allocation , the primary endpoint was measured by masked assessment of photographs . Primary analysis was intention to treat with Cox regression , with adjustment for ulcer area , ulcer duration , physical mobility , and centre . This trial is registered with the IS RCT N register , number IS RCT N49373072 . FINDINGS We r and omly allocated 457 participants to the two treatment groups : 230 to two-layer  hosiery and 227 to the four-layer b and age , of whom 453 ( 230 hosiery and 223 b and age ) contributed data for analysis . Median time to ulcer healing was 99 days ( 95 % CI 84 - 126 ) in the hosiery group and 98 days ( 85 - 112 ) in the b and age group , and the proportion of ulcers healing was much the same in the two groups ( 70·9 % hosiery and 70·4 % b and age ) . More hosiery participants changed their allocated treatment ( 38·3 % hosiery vs 27·0 % b and age ; p=0·02 ) . 300 participants had 895 adverse events , of which 85 ( 9·5 % ) were classed as serious but unrelated to trial treatment . INTERPRETATION Two-layer compression hosiery is a viable alternative to the four-layer b and age-it is equally as effective at healing venous leg ulcers . However , a higher rate of treatment changes in participants in the hosiery group than in the b and age group suggests that hosiery might not be suitable for all patients . FUNDING NIHR Health Technology Assessment programme ( 07/60/26 ) BACKGROUND Chronic venous leg ulceration can be managed by compression treatment , elevation of the leg , and exercise . The addition of ablative superficial venous surgery to this strategy has not been shown to affect ulcer healing , but does reduce ulcer recurrence . We aim ed to assess healing and recurrence rates after treatment with compression with or without surgery in people with leg ulceration . METHODS We did venous duplex imaging of ulcerated or recently healed legs in 500 consecutive patients from three centres . We r and omly allocated those with isolated superficial venous reflux and mixed superficial and deep reflux either compression treatment alone or in combination with superficial venous surgery . Compression consisted of multilayer compression b and aging every week until healing then class 2 below-knee stockings . Primary endpoints were 24-week healing rates and 12-month recurrence rates . Analysis was by intention to treat . FINDINGS 40 patients were lost to follow-up and were censored . Overall 24-week healing rates were similar in the compression and surgery 
    Output:
    
Data from one trial ( 337 participants ) suggest that high frequency ultrasound may increase the risk of non-serious adverse events ( RR 1.29 , 95 % CI 1.02 to 1.64 ; moderate quality evidence - down grade d once for imprecision ) and serious adverse events ( RR 1.21 , 95 % CI 0.78 to 1.89 ; moderate quality evidence down grade d once for imprecision).It is uncertain whether low frequency ultrasound affects venous ulcer healing at eight and 12 weeks ( RR 3.91 , 95 % CI 0.47 to 32.85 ; 2 trials , 61 participants ; very low quality evidence ( down grade d for risk of bias and imprecision)).High-frequency ultrasound probably makes little or no difference to quality of life ( moderate quality evidence , down grade d for imprecision ) .
The outcomes of adverse effects , quality of life and cost were not reported for low-frequency ultrasound treatment .
It is uncertain whether therapeutic ultrasound ( either high or low frequency ) improves the healing of venous leg ulcers .