***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: A double-blind , 18-center , balanced trial of diflunisal vs. cyclobenzaprine HCl vs. these two drugs combined vs. placebo produced complete results from 175 patients . They had sought treatment at the cooperating centers for acute painful spasms of the back within a day or two of trauma or strain . Global results over the 7 to 10 days of observations revealed a clinical ly and statistically significant superiority of the combined therapy by Day 4 ( P=0.006 ) and almost all patients recovered within a week to 10 days . A combination therapy with an effective safe analgesic and a true muscle relaxant for less than a week appears to be an excellent relief measure for acute back problems Therapeutic trials often attempt to “ blind ” patient and investigator to the true nature of treatments received , reducing the influences of conscious or subconscious prejudices . In drug trials , this is accomplished with placebo tablets , but blinding in trials of physical treatments is more problematic . This issue arose in a clinical trial of transcutaneous electrical nerve stimulation ( TENS ) for patients with chronic low back pain . Several study design features were incorporated to promote blinding : use of sham TENS units visually identical with real units , exclusion of potential subjects with previous TENS experience , avoidance of a crossover design and use of identical visit frequency , instructions and modifications in electrode placement . Subjects were asked not to discuss treatments with the clinicians who performed outcome assessment s. Both patients and clinicians were asked to guess actual treatment assignments at the trial 's end . Every patient in the true TENS group believed the unit was functioning properly , but the degree of certainty varied . In the sham TENS group , 84 % also believed they had functioning units , but their certainty was significantly less than in the active treatment group . Differences in patient perceptions did not affect compliance , as the two groups had similar dropout rates , appointment compliance , days of TENS use and daily duration of TENS use . Clinicians guessed treatments correctly 61 % of the time ( as opposed to 50 % expected by chance ) , again suggesting partial success in blinding . These efforts at blinding may partly explain the negative trial results for TENS efficacy . We conclude that complete blinding is difficult to achieve because of sensory difference in treatment and unintended communication between patient and examiner . Nonetheless , trials of physical treatments can achieve partial blinding with the techniques described here , and the success of blinding can be assessed with simple questions at study completion PURPOSE Herbal medicines are widely used for the treatment of pain , although there is not much information on their effectiveness . This study was design ed to evaluate the effectiveness of willow ( Salix ) bark extract , which is widely used in Europe , for the treatment of low back pain . SUBJECTS AND METHODS We enrolled 210 patients with an exacerbation of chronic low back pain who reported current pain of 5 or more ( out of 10 ) on a visual analog scale . They were r and omly assigned to receive an oral willow bark extract with either 120 mg ( low dose ) or 240 mg ( high dose ) of salicin , or placebo , with tramadol as the sole rescue medication , in a 4-week blinded trial . The principal outcome measure was the proportion of patients who were pain-free without tramadol for at least 5 days during the final week of the study . RESULTS The treatment and placebo groups were similar at baseline in 114 of 120 clinical features . A total of 191 patients completed the study . The numbers of pain-free patients in the last week of treatment were 27 ( 39 % ) of 65 in the group receiving high-dose extract , 15 ( 21 % ) of 67 in the group receiving low-dose extract , and 4 ( 6 % ) of 59 in the placebo group ( P < 0.001 ) . The response in the high-dose group was evident after only 1 week of treatment . Significantly more patients in the placebo group required tramadol ( P < 0.001 ) during each week of the study . One patient suffered a severe allergic reaction , perhaps to the extract . CONCLUSION Willow bark extract may be a useful and safe treatment for low back pain Study Design . Two replicate , 4-week , r and omized , double-blind , placebo-controlled , trials of rofecoxib 25 and 50 mg versus placebo for chronic low back pain . Objectives . To determine the efficacy and safety of two doses of rofecoxib compared to placebo in the treatment of chronic low back pain . Summary of Background Data . Although nonsteroidal anti-inflammatory drugs are commonly prescribed for chronic low back pain , their efficacy is unproven and toxicity can be serious . These studies evaluated the efficacy and tolerability of rofecoxib , a selective COX-2 inhibitor , in the treatment of chronic low back pain . Methods . Patients with chronic low back pain were r and omized 1:1:1 to rofecoxib 25 mg , 50 mg , or placebo once daily . Primary endpoint : Low Back Pain Intensity . Secondary endpoints : Pain Bothersomeness , Global Assessment s of Response to Therapy , Global Assessment of Disease Status , Rol and -Morris Disability Question naire , SF-12 Health Survey , Use of Rescue Acetaminophen , and Discontinuations Due to Lack of Efficacy . Results . Combining both studies , 690 patients were r and omized to placebo ( N = 228 ) ,  rofecoxib 25 mg ( N = 233 ) , or  rofecoxib 50 mg ( N = 229 ) . Mean ( ± SD ) age was 53.4 ( ± 12.9 ) years , pain duration 12.1 ( ± 11.8 ) years , 62.3 % female .  Both rofecoxib groups improved significantly . Mean differences from placebo in pain intensity were −13.50 mm , −13.81 mm ( 25 , 50 mg doses ) respectively ( P < 0.001 ) . Both regimens were superior to placebo in eight of nine secondary endpoints . Fifty mg provided no advantage over 25 mg . Both rofecoxib regimens were well tolerated , although 25 mg had a slightly better safety profile . Conclusions . Rofecoxib significantly  reduced chronic low back pain in adults and was well tolerated Objective Chronic low back pain ( CLBP ) is a widespread ailment . The aim of this study was to assess the efficacy of topiramate in the treatment of CLBP and the changes in anger status and processing , body weight , subjective pain-related disability and health-related quality of life during the course of treatment . Methods We conducted a 10-week , r and omized , double-blind , placebo-controlled study of topiramate in 96 ( 36 women ) patients with CLBP . The subjects were r and omly assigned to topiramate ( n=48 ) or placebo ( n=48 ) . Primary outcome measures were changes on the McGill Pain Question naire , State-Trait Anger Expression Inventory , Oswestry Low Back Pain Disability Question naire and SF-36 Health Survey scales , and in body weight . Results In comparison with the placebo group ( according to the intent-to-treat principle ) , significant changes on the pain rating index of McGill Pain Question naire ( Ps<0.001 ) , State-Trait Anger Expression Inventory Scales ( all Ps<0.001 ) , Oswestry Low Back Pain Disability Question naire ( P<0.001 ) , and SF-36 Health Survey scales ( all P<0.001 , except on the role-emotional scale ) were observed after 10 weeks in the patients treated with topiramate .  Weight loss was also observed and was significantly more pronounced in the group treated with topiramate than in those treated with placebo ( P<0.001 ) . Most patients tolerated topiramate relatively well but 2 patients dropped out because of side effects . Discussion Topiramate seems to be a relatively safe and effective agent in the treatment of CLBP . Significantly positive changes in pain sensitivity , anger status and processing , subjective disability , health-related quality of life , and loss of weight were observed UNLABELLED Opioid-experienced ( N = 250 ) patients with chronic , moderate to severe low back pain ( LBP ) were converted from their pre study opioid(s ) to an approximately equianalgesic dose of OPANA ER ( oxymorphone extended release ) . Patients continued slow titration , with 56 % stabilized within 1 month to a dose of OPANA ER that reduced average pain to < 40 mm on a visual analog scale with good tolerability . Stabilized patients ( n = 143 ) were r and omized to placebo or their stabilized dose of OPANA ER every 12 hours for a 12-week double-blind period . Pain intensity increased significantly more for patients r and omized to placebo than for patients who continued their stabilized dose of OPANA ER ; the increase from baseline ( at r and omization ) to final visit was 31.6 mm for placebo versus 8.7 mm with OPANA ER ( P < .0001 ) . During double-blind treatment , placebo patients were approximately 8-fold more likely than OPANA ER patients to discontinue because of lack of efficacy ( P < .001 ) . Discontinuations as a result of adverse events were similar between groups , 10 % with placebo and 11 % with OPANA ER . Opioid-related adverse events included constipation ( 6 % ) , somnolence ( 3 % ) , and nausea ( 3 % ) . Fifty-seven percent of opioid-experienced patients with chronic , moderate to severe LBP achieved a stable dose of OPANA ER that was efficacious and generally well-tolerated for up to 12 weeks . PERSPECTIVE In a 12-week , double-blind , r and omized , placebo-controlled trial in opioid-experienced patients with chronic , moderate to severe LBP , OPANA ER provided efficacious , long-term analgesia and was generally well-tolerated . OPANA ER may provide clinicians with a new treatment option for patients experiencing suboptimal analgesic responses or poor tolerability with other opioids Previous studies have shown a positive association between pain and depression  , though evidence supporting a direct link between these two variables is less robust . Using a placebo-controlled trial , the authors examined the analgesic and antidepressant efficacy of paroxetine ( 20 mg ) in chronic low back pain sufferers . The authors examined the associations among pain , depression , disability , and illness attitudes .  Paroxetine showed no effects on pain or depression compared with placebo ; however , subjects r and omized to paroxetine were more likely to reduce concomitant analgesic medication . The cross-sectional association of depression and pain at baseline ( r = 0.2 , P = 0.02 ) was weaker than the association between depression and disability ( r = 0.3 , P = 0.004 ) . Similarly , the association of change in depression scores with change in pain ( r = 0.25 , P = 0.016 ) was weaker than change between depression and disability ( r = 0.49 , P<0.0005 ) . Whereas the relationship between pain and depression became nonsignificant when disability and illness attitudes were controlled , the relationship between depression and disability remained highly significant when pain and illness attitudes were controlled . These data are consistent with the association between pain and depression being wholly modulated by disability and illness attitudes , with no direct relationship between pain and depression BACKGROUND The effectiveness of massage therapy for low-back pain has not been documented . This r and omized controlled trial compared comprehensive massage therapy ( soft-tissue manipulation , remedial exercise and posture education ) , 2 components of massage therapy and placebo in the treatment of subacute ( between 1 week and 8 months ) low-back pain . METHODS Subjects with subacute low-back pain were r and omly assigned to 1 of 4 groups : comprehensive massage therapy ( n = 25 ) , soft-tissue manipulation only ( n = 25 ) , remedial exercise with posture education only ( n = 22 ) or a placebo of sham laser therapy ( n = 26 ) . Each subject received 6 treatments within approximately 1 month . Outcome measures obtained at baseline , after treatment and at 1-month follow-up consisted of the Rol and Disability Question naire ( RDQ ) , the McGill Pain Question naire ( PPI and PRI ) , the State Anxiety Index and the Modified Schober test ( lumbar range of motion ) . RESULTS Of the 107 subjects who passed screening , 98 ( 92 % ) completed post-treatment tests and 91 ( 85 % ) completed follow-up tests . Statistically significant differences were noted after treatment and at follow-up . The comprehensive massage therapy group had improved function ( mean RDQ score 1.54 v. 2.86 - 6.5 , p < 0.001 ) , less intense pain ( mean PPI score 0.42 v. 1.18 - 1.75 , p < 0.001 ) and a decrease in the quality of pain ( mean PRI score 2.29 v. 4.55 - 7.71 , p = 0.006 ) compared with the other 3 groups . Clinical significance was evident for the comprehensive massage therapy group and the soft-tissue manipulation group on the measure of function . At 1-month follow-up 63 % of subjects in the comprehensive massage therapy group reported no pain as compared with 27 % of the soft-tissue manipulation group , 14 % of the remedial exercise group and 0 % of the sham laser therapy group . INTERPRETATION Patients with 
    Output:
    
Although the evidence from studies using sham laser was inconclusive , the present review did find a clinical ly meaningful change in LBP scores following the use of sham oral medications .
CONCLUSIONS The present best- evidence review found a clinical ly meaningful change in pain scores following the use of sham oral medications for the treatment of nonspecific LBP .