human
***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: Background Only controlled blocks are capable of confirming the zygapophysial joints ( ZJ ) as the pain generator in LBP patients . However , previous workers have found that a cluster of clinical signs ( " Revel 's criteria ") , may be valuable in predicting the results of an initial screening ZJ block . It was suggested that these clinical findings are unsuitable for diagnosis , but may be of value in selecting patients for diagnostic blocks of the lumbar ZJ 's . To constitute evidence in favour of a clinical management strategy , these results need confirmation . This study evaluates the utility of ' Revel 's criteria ' as a screening tool for selection of chronic low back pain patients for controlled ZJ diagnostic blocks . Methods This study utilized a prospect i ve blinded concurrent reference st and ard related validity design . Consecutive chronic LBP patients completed pain drawings , psychosocial distress and disability question  naires  , received a clinical examination and lumbar zygapophysial blocks . Two reference st and ards were evaluated simultaneously : 1 . 75 % reduction of pain on a visual analogue scale ( replication of previous work ) , and 2 . abolition of the dominant or primary pain . Using " Revel 's criteria " as predictors , logistic regression analyses were used to test the model . Estimates of sensitivity , specificity , predictive values and likelihood ratios for selected variables were calculated for the two proposed clinical strategies . Results Earlier results were not replicated . Sensitivity of " Revel 's criteria " was low sensitivity ( < 17 % ) , and specificity high ( approximately 90 % ) . Absence of pain with cough or sneeze just reached significance ( p = 0.05 ) within one model . Conclusions " Revel 's criteria " are unsuitable as a clinical screening test to select chronic LBP patients for initial ZJ blocks . However , the criteria may have use in identifying a small subset ( 11 % ) of patients likely to respond to the initial block ( specificity 93 % ) Study Design This prospect i ve study evaluated the diagnostic utility of historically accepted sacroiliac joint tests . A multidisciplinary expert panel recommended 12 of the “ best ” sacroiliac joint tests to be evaluated against a criterion st and ard of unequivocal pain relief after an intra‐articular injection of local anesthetic into the sacroiliac joint . Objectives To identify a single sacroiliac joint test or ensemble of tests that are sufficiently useful in diagnosing sacroiliac joint disorders to be clinical ly valuable . Summary of Background Data No previous research has been done to evaluate any physical test of sacroiliac joint pain against an accepted criterion st and ard . Methods Historical data was obtained , and the 12 tests were performed by two examiners on 85 patients who subsequently underwent sacroiliac joint blocks .  Ninety percent or more relief was considered a positive response , and less then 90 % relief was considered a negative response . Results There were 45 positive and 40 negative responses . No historical feature , none of the 12 sacroiliac joint tests , and no ensemble of these 12 tests demonstrated worthwhile diagnostic value . Conclusion Sacroiliac joint pain is resistant to identification by the historical and physical examination data from tests evaluated in this study Abstract A prospect i ve study was performed to compare the results of quantitative radionuclide bone scanning with those of sacroiliac joint anesthetic block in patients with unilateral low back pain . Thirty-four subjects , forming the control group , underwent quantitative radionuclide bone scanning of the sacroiliac joints . The normal values in sacroiliac uptake difference were taken to be between –1.7 % and + 6.2 % . Thirty-two patients with chronic unilateral low back pain underwent sacroiliac bone scanning and sacroiliac joint block . Six of the seven patients with increased uptake > 6.2 % on the painful side had at least 75 % pain reduction in response to the block . The sensitivity , specificity , and positive and negative predictive values of the quantitative bone scanning in the unilateral mechanical sacroiliac joint syndrome were 46.1 % , 89.5 % , 85.7 % , and 72 % , respectively BACKGROUND Only controlled intra-articular zygapophyseal joint ( ZJ ) injections or medial branch blocks can diagnose ZJ-mediated low back pain . The low prevalence of ZJ pain implies that identification of clinical predictors of a positive response to a screening block is needed . PURPOSE To estimate the predictive power of clinical findings in relation to pain reduction after screening ZJ blocks . STUDY DESIGN As part of a wider prospect i ve blinded study investigating diagnostic accuracy of clinical variables , a secondary analysis was carried out to seek evidence of variables potentially valuable as predictors of screening ZJ block outcomes . PATIENT SAMPLE Chronic low back pain patients received screening ZJ blocks ( n=151 ) with 120 patients included in the analysis after exclusions . OUTCOME MEASURES Pain intensity was measured using a 100-mm visual analog scale , and responses were categorized according to 75 % through 95 % or more pain reduction in 5 % increments . METHODS Patients completed pain drawings , question naires , and a clinical examination before screening lumbar ZJ blocks . History , demographic and clinical variables were evaluated in cross tabulation and regression analyses with diagnostic accuracy values calculated for variables and variable clusters in relation to different pain reduction st and ards . RESULTS At the 75 % pain reduction st and ard , 24.5 % responded to screening ZJ blocks and 10.8 % responded at the 95 % st and ard . The central ization phenomenon is not associated with pain reduction using any st and ard . No variables were useful predictors of post-ZJ block pain reduction of less than 90 % . Seven clinical findings were associated with 95 % pain reduction after blocks . Five useful clinical prediction rules ( CPRs ) were found for ruling out a 95 % pain reduction ( 100 % sensitivity ) , and one CPR had a likelihood ratio of 9.7 , producing a fivefold improvement in posttest probability . CONCLUSIONS A negative extension rotation test , the central ization phenomenon , and four CPRs effectively rule out pain ablation after screening ZJ block . One CPR generates a fivefold improvement in posttest probability of a negative or positive response to ZJ block Although radial tear of the annulus fibrosus can be detected on T2-weighted and Gd-DTPA-enhanced magnetic resonance ( MR ) images , the association between the annular tear on MR images and the symptomatic discs is unclear . The purpose of this study was to investigate the relationship between T2-weighted , gadolinium-DTPA-enhanced MR images and pain response through discography in patients with chronic low back pain . A total of 56 lumbar discs from 23 patients with chronic low back pain ( 13 to 47 years old ) underwent MR imaging ( T2-weighted , gadolinium-DTPA-enhanced MR images ) followed by provocative discography . The sensitivity , specificity , positive predictive value , and negative predictive value of T2-weighted and gadolinium-DTPA-enhanced MR images in detecting the symptomatic discs were calculated . The sensitivity , specificity , positive predictive value , and negative predictive value of T2-weighted images in detecting the symptomatic disc were 94 % , 71 % , 59 % , and 97 % , respectively . The sensitivity , specificity , positive predictive value , and negative predictive value of gadolinium-DTPA-enhanced images were 71 % , 75 % , 56 % , and 86 % , respectively . The high sensitivity and the high negative predictive value of T2-weighted MR imaging in detecting the symptomatic disc indicated that MR imaging can be a useful screening tool in avoiding unnecessary discography in patients with chronic low back pain Previous research indicates that physical examination can not diagnose sacroiliac joint ( SIJ ) pathology . Earlier studies have not reported sensitivities and specificities of composites of provocation tests known to have acceptable inter-examiner reliability . This study examined the diagnostic power of pain provocation SIJ tests singly and in various combinations , in relation to an accepted criterion st and ard . In a blinded criterion-related validity design , 48 patients were examined by physiotherapists using pain provocation SIJ tests and received an injection of local anaesthetic into the SIJ .  The tests were evaluated singly and in various combinations ( composites ) for diagnostic power . All patients with a positive response to diagnostic injection reported pain with at least one SIJ test . Sensitivity and specificity for three or more of six positive SIJ tests were 94 % and 78 % , respectively . Receiver operator characteristic curves and areas under the curve were constructed for various composites . The greatest area under the curve for any two of the best four tests was 0.842 . In conclusion , composites of provocation SIJ tests are of value in clinical diagnosis of symptomatic SIJ . Three or more out of six tests or any two of four selected tests have the best predictive power in relation to results of intra-articular anaesthetic block injections . When all six provocation tests do not provoke familiar pain , the SIJ can be ruled out as a source of current LBP OBJECTIVE To compare the diagnostic accuracy of a multitest regimen of 5 sacroiliac joint ( SIJ ) pain provocation tests with fluoroscopically controlled double SIJ blocks using a short- and long-acting local anesthetic in order to reduce the exposure of patients to unnecessary invasive SIJ procedures . DESIGN Prospect i ve , observational study . SETTING Hospital setting . PARTICIPANTS Sixty patients with chronic low back pain . INTERVENTIONS Not applicable . MAIN OUTCOME MEASURES Visual analog scale score and receiver operating characteristic ( ROC ) curve . RESULTS Twenty-seven patients responded positively to the blocks , of whom 23 were found positive after the multitest regimen and 4 were negative . For the nonresponders ( n=33 ) , these figures were 7 positive and 26 negative . The calculated sensitivity and specificity were .85 ( 95 % confidence interval [ CI ] , .72-.99 ) and .79 ( 95 % CI , .65-.93 ) , respectively . Positive and negative predictive values were .77 ( 95 % CI , .62-.92 ) and .87 ( 95 % CI , .74-.99 ) , respectively . The positive likelihood ratio was 4.02 ( 95 % CI , 2.04 - 7.89 ) ; the negative likelihood ratio was .19 ( 95 % CI , .07-.47 ) . The area under the ROC curve was .799 . CONCLUSIONS The test regimen with 3 or more positive tests is indicative of SIJ pain . It can be used in early clinical decision making to reduce the number of unnecessary minimally invasive diagnostic SIJ procedures BACKGROUND CONTEXT Lumbar discography has been widely used for evaluating discogenic low back pain ( LBP ) . Comparison of pain responses from suspected symptomatic discs with pain responses from asymptomatic negative discs is routine . However , the ability of discography to distinguish asymptomatic morphologically abnormal discs from those that are symptomatic has been understudied . In addition , the discographic characteristics of negative discs in patients with chronic discogenic LBP have not been reported . Criteria for negative morphologically abnormal discs may be valuable for excluding discs from further treatment and examination . PURPOSE To determine if discography can distinguish asymptomatic discs among morphologically abnormal discs in patients with suspected chronic discogenic LBP and establish the st and ard characteristics of negative discs . STUDY DESIGN / SETTING Prospect i ve , experimental with control group . PATIENT SAMPLE Fifty-five discs from a control group of 16 healthy volunteers without current back pain ( 11 men , 5 women , 32 - 61 years of age , mean age : 47 years ) and 282 discs from a patient group of 90 LBP patients ( 59 men , 31 women , 20 - 70 years of age , mean age : 44.7 years ) were recruited . METHODS Discography was performed using a pressure-controlled manometric technique with an injection rate of 0.05 mL/s and a 3.5 mL restricted total volume . Concordance was rated as none/unfamiliar , or familiar . Pain was rated via a 0 - 10 numerical rating scale ( NRS ) . The pressure and volume at which pain was evoked and NRS pain responses at 15 , 30 , and 50 psi were recorded . Annular disruption grade was rated during the procedure by computed tomography discography and fluoroscopic imaging . Negative discogram required no pain described by the participant as " familiar , " with no pain responses > or=6/10 NRS at pressures < or=50 psi above opening pressure and < or=3.5 mL total injected volume . Patient discs were partitioned into two subgroups based on discographic findings : Neg-D ( negative discs ) and Pos-D ( positive discs ) . Only discs with Grade 3 annular tears ( Dallas Discogram Scale ) were included in the study . RESULTS Among 55 asymptomatic control group discs , 32 ( 58.2 % ) exhibited Grade 3 annular tear . All discs in the asymptomatic control group satisfied negative response criteria . Among 282 patient group discs , 199 ( 70.6 % ) exhibited Grade 3 annular tear . Of 199 discs with Grade 3 annular tears , 104 ( 52.3 % ) satisfied negative response criteria and were categorized as the Neg-D group . The other 95 discs were categorized as a Pos-D group . Patients showed significantly lower pain tolerance relative to control subjects ( p<.05 ) . The control and Neg-D groups showed similar pressures and volumes at which pain was initially evoked . Mean control group pain scores were 0.47 NRS at 15 psi and 1.58 NRS at 50 psi . Mean Neg-D group pain scores 
    Output:
    
agent
The results of this review demonstrate that tests do exist that change the probability of the disc or SIJ ( but not the facet joint ) as the source of low back pain .
***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: Background Only controlled blocks are capable of confirming the zygapophysial joints ( ZJ ) as the pain generator in LBP patients . However , previous workers have found that a cluster of clinical signs ( " Revel 's criteria ") , may be valuable in predicting the results of an initial screening ZJ block . It was suggested that these clinical findings are unsuitable for diagnosis , but may be of value in selecting patients for diagnostic blocks of the lumbar ZJ 's . To constitute evidence in favour of a clinical management strategy , these results need confirmation . This study evaluates the utility of ' Revel 's criteria ' as a screening tool for selection of chronic low back pain patients for controlled ZJ diagnostic blocks . Methods This study utilized a prospect i ve blinded concurrent reference st and ard related validity design . Consecutive chronic LBP patients completed pain drawings , psychosocial distress and disability question  naires  , received a clinical examination and lumbar zygapophysial blocks . Two reference st and ards were evaluated simultaneously : 1 . 75 % reduction of pain on a visual analogue scale ( replication of previous work ) , and 2 . abolition of the dominant or primary pain . Using " Revel 's criteria " as predictors , logistic regression analyses were used to test the model . Estimates of sensitivity , specificity , predictive values and likelihood ratios for selected variables were calculated for the two proposed clinical strategies . Results Earlier results were not replicated . Sensitivity of " Revel 's criteria " was low sensitivity ( < 17 % ) , and specificity high ( approximately 90 % ) . Absence of pain with cough or sneeze just reached significance ( p = 0.05 ) within one model . Conclusions " Revel 's criteria " are unsuitable as a clinical screening test to select chronic LBP patients for initial ZJ blocks . However , the criteria may have use in identifying a small subset ( 11 % ) of patients likely to respond to the initial block ( specificity 93 % ) Study Design This prospect i ve study evaluated the diagnostic utility of historically accepted sacroiliac joint tests . A multidisciplinary expert panel recommended 12 of the “ best ” sacroiliac joint tests to be evaluated against a criterion st and ard of unequivocal pain relief after an intra‐articular injection of local anesthetic into the sacroiliac joint . Objectives To identify a single sacroiliac joint test or ensemble of tests that are sufficiently useful in diagnosing sacroiliac joint disorders to be clinical ly valuable . Summary of Background Data No previous research has been done to evaluate any physical test of sacroiliac joint pain against an accepted criterion st and ard . Methods Historical data was obtained , and the 12 tests were performed by two examiners on 85 patients who subsequently underwent sacroiliac joint blocks .  Ninety percent or more relief was considered a positive response , and less then 90 % relief was considered a negative response . Results There were 45 positive and 40 negative responses . No historical feature , none of the 12 sacroiliac joint tests , and no ensemble of these 12 tests demonstrated worthwhile diagnostic value . Conclusion Sacroiliac joint pain is resistant to identification by the historical and physical examination data from tests evaluated in this study Abstract A prospect i ve study was performed to compare the results of quantitative radionuclide bone scanning with those of sacroiliac joint anesthetic block in patients with unilateral low back pain . Thirty-four subjects , forming the control group , underwent quantitative radionuclide bone scanning of the sacroiliac joints . The normal values in sacroiliac uptake difference were taken to be between –1.7 % and + 6.2 % . Thirty-two patients with chronic unilateral low back pain underwent sacroiliac bone scanning and sacroiliac joint block . Six of the seven patients with increased uptake > 6.2 % on the painful side had at least 75 % pain reduction in response to the block . The sensitivity , specificity , and positive and negative predictive values of the quantitative bone scanning in the unilateral mechanical sacroiliac joint syndrome were 46.1 % , 89.5 % , 85.7 % , and 72 % , respectively BACKGROUND Only controlled intra-articular zygapophyseal joint ( ZJ ) injections or medial branch blocks can diagnose ZJ-mediated low back pain . The low prevalence of ZJ pain implies that identification of clinical predictors of a positive response to a screening block is needed . PURPOSE To estimate the predictive power of clinical findings in relation to pain reduction after screening ZJ blocks . STUDY DESIGN As part of a wider prospect i ve blinded study investigating diagnostic accuracy of clinical variables , a secondary analysis was carried out to seek evidence of variables potentially valuable as predictors of screening ZJ block outcomes . PATIENT SAMPLE Chronic low back pain patients received screening ZJ blocks ( n=151 ) with 120 patients included in the analysis after exclusions . OUTCOME MEASURES Pain intensity was measured using a 100-mm visual analog scale , and responses were categorized according to 75 % through 95 % or more pain reduction in 5 % increments . METHODS Patients completed pain drawings , question naires , and a clinical examination before screening lumbar ZJ blocks . History , demographic and clinical variables were evaluated in cross tabulation and regression analyses with diagnostic accuracy values calculated for variables and variable clusters in relation to different pain reduction st and ards . RESULTS At the 75 % pain reduction st and ard , 24.5 % responded to screening ZJ blocks and 10.8 % responded at the 95 % st and ard . The central ization phenomenon is not associated with pain reduction using any st and ard . No variables were useful predictors of post-ZJ block pain reduction of less than 90 % . Seven clinical findings were associated with 95 % pain reduction after blocks . Five useful clinical prediction rules ( CPRs ) were found for ruling out a 95 % pain reduction ( 100 % sensitivity ) , and one CPR had a likelihood ratio of 9.7 , producing a fivefold improvement in posttest probability . CONCLUSIONS A negative extension rotation test , the central ization phenomenon , and four CPRs effectively rule out pain ablation after screening ZJ block . One CPR generates a fivefold improvement in posttest probability of a negative or positive response to ZJ block Although radial tear of the annulus fibrosus can be detected on T2-weighted and Gd-DTPA-enhanced magnetic resonance ( MR ) images , the association between the annular tear on MR images and the symptomatic discs is unclear . The purpose of this study was to investigate the relationship between T2-weighted , gadolinium-DTPA-enhanced MR images and pain response through discography in patients with chronic low back pain . A total of 56 lumbar discs from 23 patients with chronic low back pain ( 13 to 47 years old ) underwent MR imaging ( T2-weighted , gadolinium-DTPA-enhanced MR images ) followed by provocative discography . The sensitivity , specificity , positive predictive value , and negative predictive value of T2-weighted and gadolinium-DTPA-enhanced MR images in detecting the symptomatic discs were calculated . The sensitivity , specificity , positive predictive value , and negative predictive value of T2-weighted images in detecting the symptomatic disc were 94 % , 71 % , 59 % , and 97 % , respectively . The sensitivity , specificity , positive predictive value , and negative predictive value of gadolinium-DTPA-enhanced images were 71 % , 75 % , 56 % , and 86 % , respectively . The high sensitivity and the high negative predictive value of T2-weighted MR imaging in detecting the symptomatic disc indicated that MR imaging can be a useful screening tool in avoiding unnecessary discography in patients with chronic low back pain Previous research indicates that physical examination can not diagnose sacroiliac joint ( SIJ ) pathology . Earlier studies have not reported sensitivities and specificities of composites of provocation tests known to have acceptable inter-examiner reliability . This study examined the diagnostic power of pain provocation SIJ tests singly and in various combinations , in relation to an accepted criterion st and ard . In a blinded criterion-related validity design , 48 patients were examined by physiotherapists using pain provocation SIJ tests and received an injection of local anaesthetic into the SIJ .  The tests were evaluated singly and in various combinations ( composites ) for diagnostic power . All patients with a positive response to diagnostic injection reported pain with at least one SIJ test . Sensitivity and specificity for three or more of six positive SIJ tests were 94 % and 78 % , respectively . Receiver operator characteristic curves and areas under the curve were constructed for various composites . The greatest area under the curve for any two of the best four tests was 0.842 . In conclusion , composites of provocation SIJ tests are of value in clinical diagnosis of symptomatic SIJ . Three or more out of six tests or any two of four selected tests have the best predictive power in relation to results of intra-articular anaesthetic block injections . When all six provocation tests do not provoke familiar pain , the SIJ can be ruled out as a source of current LBP OBJECTIVE To compare the diagnostic accuracy of a multitest regimen of 5 sacroiliac joint ( SIJ ) pain provocation tests with fluoroscopically controlled double SIJ blocks using a short- and long-acting local anesthetic in order to reduce the exposure of patients to unnecessary invasive SIJ procedures . DESIGN Prospect i ve , observational study . SETTING Hospital setting . PARTICIPANTS Sixty patients with chronic low back pain . INTERVENTIONS Not applicable . MAIN OUTCOME MEASURES Visual analog scale score and receiver operating characteristic ( ROC ) curve . RESULTS Twenty-seven patients responded positively to the blocks , of whom 23 were found positive after the multitest regimen and 4 were negative . For the nonresponders ( n=33 ) , these figures were 7 positive and 26 negative . The calculated sensitivity and specificity were .85 ( 95 % confidence interval [ CI ] , .72-.99 ) and .79 ( 95 % CI , .65-.93 ) , respectively . Positive and negative predictive values were .77 ( 95 % CI , .62-.92 ) and .87 ( 95 % CI , .74-.99 ) , respectively . The positive likelihood ratio was 4.02 ( 95 % CI , 2.04 - 7.89 ) ; the negative likelihood ratio was .19 ( 95 % CI , .07-.47 ) . The area under the ROC curve was .799 . CONCLUSIONS The test regimen with 3 or more positive tests is indicative of SIJ pain . It can be used in early clinical decision making to reduce the number of unnecessary minimally invasive diagnostic SIJ procedures BACKGROUND CONTEXT Lumbar discography has been widely used for evaluating discogenic low back pain ( LBP ) . Comparison of pain responses from suspected symptomatic discs with pain responses from asymptomatic negative discs is routine . However , the ability of discography to distinguish asymptomatic morphologically abnormal discs from those that are symptomatic has been understudied . In addition , the discographic characteristics of negative discs in patients with chronic discogenic LBP have not been reported . Criteria for negative morphologically abnormal discs may be valuable for excluding discs from further treatment and examination . PURPOSE To determine if discography can distinguish asymptomatic discs among morphologically abnormal discs in patients with suspected chronic discogenic LBP and establish the st and ard characteristics of negative discs . STUDY DESIGN / SETTING Prospect i ve , experimental with control group . PATIENT SAMPLE Fifty-five discs from a control group of 16 healthy volunteers without current back pain ( 11 men , 5 women , 32 - 61 years of age , mean age : 47 years ) and 282 discs from a patient group of 90 LBP patients ( 59 men , 31 women , 20 - 70 years of age , mean age : 44.7 years ) were recruited . METHODS Discography was performed using a pressure-controlled manometric technique with an injection rate of 0.05 mL/s and a 3.5 mL restricted total volume . Concordance was rated as none/unfamiliar , or familiar . Pain was rated via a 0 - 10 numerical rating scale ( NRS ) . The pressure and volume at which pain was evoked and NRS pain responses at 15 , 30 , and 50 psi were recorded . Annular disruption grade was rated during the procedure by computed tomography discography and fluoroscopic imaging . Negative discogram required no pain described by the participant as " familiar , " with no pain responses > or=6/10 NRS at pressures < or=50 psi above opening pressure and < or=3.5 mL total injected volume . Patient discs were partitioned into two subgroups based on discographic findings : Neg-D ( negative discs ) and Pos-D ( positive discs ) . Only discs with Grade 3 annular tears ( Dallas Discogram Scale ) were included in the study . RESULTS Among 55 asymptomatic control group discs , 32 ( 58.2 % ) exhibited Grade 3 annular tear . All discs in the asymptomatic control group satisfied negative response criteria . Among 282 patient group discs , 199 ( 70.6 % ) exhibited Grade 3 annular tear . Of 199 discs with Grade 3 annular tears , 104 ( 52.3 % ) satisfied negative response criteria and were categorized as the Neg-D group . The other 95 discs were categorized as a Pos-D group . Patients showed significantly lower pain tolerance relative to control subjects ( p<.05 ) . The control and Neg-D groups showed similar pressures and volumes at which pain was initially evoked . Mean control group pain scores were 0.47 NRS at 15 psi and 1.58 NRS at 50 psi . Mean Neg-D group pain scores 
    Output:
    