***TASK***
the task is to simplify the input abstract of a biomedical literature

***INPUT***
the input is the abstract of a biomedical literature

***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature

***DOCUMENTATION***

***EXAMPLES***

Input: We identified three RCTs, all of which compared EVLA with surgery; one also compared UGFS with surgery. There were no trials comparing RFA with surgery. The EVLA versus surgery comparison included 311 participants: 185 received EVLA and 126 received surgery. In the UGFS comparison, each treatment group contained 21 people. For several outcomes in the EVLA comparison, only a single study provided relevant data; as a result, the current review is limited in its ability to demonstrate meaningful results for some planned outcomes. The quality of evidence according to GRADE was moderate to low for the outcome measures in the EVLA versus surgery comparison, but low for the UGFS versus surgery comparison. Reasons for downgrading in the EVLA versus surgery comparison were risk of bias (for some outcomes, the outcome assessors were not blinded; and in one study the EVLA-surgery allocation of 2:1 did not appear to be prespecified); imprecision (data were only available from a single small study and the CIs were relatively wide); indirectness (one trial reported results at six months rather than one year and was inadequately powered for SSV varices-only analysis). Reasons for downgrading in the UGFS versus surgery comparison were imprecision (only one trial offered UGFS and several participants were missing from the analysis) and a limitation in design (the study was inadequately powered for SSV participants alone). For the EVLA versus surgery comparison, recanalisation or persistence of reflux at six weeks occurred less frequently in the EVLA group than in the surgery group (OR 0.07, 95% CI 0.02 to 0.22; I2 = 51%; 289 participants, 3 studies, moderate-quality evidence). Recurrence of reflux at one year was also less frequent in the EVLA group than in the surgery group (OR 0.24, 95% CI 0.07 to 0.77; I2 = 0%; 119 participants, 2 studies, low-quality evidence). For the outcome clinical evidence of recurrence (i.e. presence of new visible varicose veins) at one year, there was no difference between the two treatment groups (OR 0.54, 95% CI 0.17 to 1.75; 99 participants, 1 study, low-quality evidence). Four participants each in the EVLA and surgery groups required reintervention due to technical failure (99 participants, 1 study, moderate-quality evidence). There was no difference between the two treatment groups for disease-specific quality of life (QoL) (Aberdeen Varicose Veins Questionnaire) either at six weeks (mean difference (MD) 0.15, 95% CI -1.65 to 1.95; I2 = 0%; 265 participants, 2 studies, moderate-quality evidence), or at one year (MD -1.08, 95% CI -3.39 to 1.23; 99 participants, 1 study, low-quality evidence). Main complications reported at six weeks were sural nerve injury, wound infection and deep venous thrombosis (DVT) (one DVT case in each treatment group; EVLA: 1/161, 0.6%; surgery 1/104, 1%; 265 participants, 2 studies, moderate-quality evidence). For the UGFS versus surgery comparison, there were insufficient data to detect clear differences between the two treatment groups for the two outcomes recanalisation or persistence of reflux at six weeks (OR 0.34, 95% CI 0.06 to 2.10; 33 participants, 1 study, low-quality evidence), and recurrence of reflux at one year (OR 1.19, 95% CI 0.29 to 4.92; 31 participants, 1 study, low-quality evidence). No other outcomes could be reported for this comparison because the study data were not stratified according to saphenous vein. Moderate- to low-quality evidence exists to suggest that recanalisation or persistence of reflux at six weeks and recurrence of reflux at one year are less frequent when EVLA is performed, compared with conventional surgery. For the UGFS versus conventional surgery comparison, the quality of evidence is assessed to be low; consequently, the effectiveness of UGFS compared with conventional surgery in the treatment of SSV varices is uncertain. Further RCTs for all comparisons are required with longer follow-up (at least five years). In addition, measurement of outcomes such as recurrence of reflux, time taken to return to work, duration of procedure, pain, etc., and choice of time points during follow-up should be standardised such that future trials evaluating newer technologies can be compared efficiently.
Output:

We searched for all randomised controlled trials to March 2016 that compared at least one of the newer techniques with surgery, when treating short saphenous vein (SSVs; found in the lower leg) varices. We found three trials comparing EVLA with surgery; one trial compared UGFS with surgery, but none reported RFA. The main measures (outcomes) were recanalisation (blood flowing in the veins again) or persistence of reflux (due to failure of treatment) at six weeks; recurrence of reflux at one year; clinical evidence of recurrence (presence of new varicose veins) at one year; repeat treatment due to failure; quality of life (QoL) at six weeks and one year after the treatment; and complications after treatment. The EVLA versus surgery comparison included 311 participants: 185 received EVLA and 126 received surgery. In the UGFS comparison, each treatment group contained 21 people. For several outcomes in the EVLA comparison, only one study provided data; consequently, this review has limited ability to demonstrate meaningful results for some planned outcomes. EVLA versus surgery: there was less recanalisation or persistence of reflux at six weeks and less recurrence of reflux at one year in the EVLA group; however, there were insufficient data to report clear differences in clinical recurrence at one year. One trial reported four participants in each group required further treatment. There was no difference between treatments in QoL. Although some participants had postoperative complications (e.g., sural nerve injury (the sural nerve is in the calf), infection, deep venous thrombosis (DVT; blood clots in veins), inflammation of the wall of the vein), most complications improved without treatment and the two cases of DVT resolved after treatment with medicines. UGFS versus surgery: there were insufficient data to detect clear differences between treatment groups for recanalisation or persistence of reflux at six weeks and recurrence of reflux at one year. Data were not available for other outcomes. For the EVLA comparison, the quality of evidence was moderate for recanalisation or persistence of reflux, QoL and complications, all at six weeks, and retreatment due to technical failure, but low for recurrence of reflux, QoL and clinical evidence of recurrence after one year. The quality of evidence was downgraded due to imprecision (small number of trials with few participants) and bias (outcome assessors aware of treatment allocation in some studies and one study recruited insufficient participants with SSV). For the UGFS comparison, evidence was low quality because one study (with few participants with SSV) offered UGFS and several participants were missing from the analysis. The main difficulty with this review was lack of data: we found a small number of trials and two trials had substantial amounts of unavailable data. Further well-designed studies are needed.