urinary retention and voiding dysfunction ( vd ) symptoms ( hesitancy , straining to void , difficulty in starting micturition , diminished stream , and sensations of incomplete emptying of the bladder ) are common and problematic features occurring after surgery for stress urinary incontinence ( sui ) , especially following a mid - urethral sling placement ( retropubic or trans - obturator procedure ) . they can lead to urinary infections , and can also require self - catheterization or sling section . the prevalence of urinary retention varies from 2.216% after surgery for sui.[13 ] preexisting voiding dysfunction is known to be a predictive factor for post - surgery urinary retention . in 2003 hong et al . , showed that the best predictive factor for obstructive complications was the maximum flow rate , with which it was shown to be directly correlated . it is thus important to screen women suffering from sui for emptying symptoms before such surgery . the purpose of this study was to determine whether the completion of a vd questionnaire could have a good predictive value for uroflowmetry findings , in a population of sui women showing no obvious etiologies of obstruction . we analyzed 415 sui women from the urodynamic database , who had undergone a filling cystometry in the department , and whose uroflowmetry indicated a total urine volume greater than 200 ml . women with neurological disorders , pelvic organ prolapse , urge or mixed urinary incontinence , detrusor overactivity or previous sui surgery were excluded . with these exclusion criteria , these 93 women were divided into two groups : those who complained of vd symptoms ( vds group ) according to the bristol female lower urinary tract symptoms ( bfluts ) questionnaire , and those without vd symptoms ( non - vds group ) . we investigated the parity , age , menopausal status , and concomitant anorectal disorders of each woman . the women were interviewed on the presence of emptying symptoms , and completed the bfluts questionnaire [ table 1 ] , which is systematic in our department . we screened for five items related to voiding difficulties : hesitancy , slow or intermittent stream , straining , or sensations of incomplete emptying . for the purposes of data analysis , those women who answered  never  to all five items were classed in the non - vds group . those women for whom one or more of the answers was positive ( i.e. :  occasionally , sometimes , most of the time or all the time  ) , were classified in the vds group . bristol questionnarire bfluts ( urinary symptoms questionnaire ) : the five items concerning voiding dysfunction the clinical examination included a physical examination , urodynamic testing and a  free flow uroflowmetry and filling cystometry at a rate of 50 ml per minute ( duet , medtronic ) . the filling cystometry parameters studied were : compliance , detrusor overactivity ( do ) , detrusor sensation . none of the patients presented with abnormal compliance , do , or abnormal detrusor sensation . both a quantitative and a qualitative analysis of bladder outlet obstruction ( boo ) was made by uroflowmetry . quantitatively , a patient was considered to have boo when a maximum flow rate of less than 15 ml / sec was observed for a urine volume greater than 200 ml , and/or the post - void residual was greater than 50 ml , as measured with a bladder scan or by catheterization . the urine flow was also analyzed in terms of average flow rate , urine volume , voiding time and acceleration ( defined as the maximum flow rate divided by the time taken to reach maximum flow rate ) . the qualitative analysis dealt with the flow patterns : a standard  bell - shaped three pathologic patterns were considered : intermittent or continuous polyphasic curves , and flat curves [ figures 1a  c ] . we determined the sensitivity and specificity as well as the positive and negative predictive value of the vds questionnaire using the uroflowmetry data . ( a ) intermittent polyphasic curve ( b ) continuous polyphasic curve ( c ) flat curve a comparison of the clinical characteristics and uroflowmetry of the two groups was made using a wilcoxon test for continuous data and a fischer test for categorical data . as the bfluts questionnaire and urodynamics were identical to those systematically used for the routine evaluation of sui women in our department , the study did not require specific ethics committee approbation . we analyzed 415 sui women from the urodynamic database , who had undergone a filling cystometry in the department , and whose uroflowmetry indicated a total urine volume greater than 200 ml . women with neurological disorders , pelvic organ prolapse , urge or mixed urinary incontinence , detrusor overactivity or previous sui surgery were excluded . with these exclusion criteria , these 93 women were divided into two groups : those who complained of vd symptoms ( vds group ) according to the bristol female lower urinary tract symptoms ( bfluts ) questionnaire , and those without vd symptoms ( non - vds group ) . we investigated the parity , age , menopausal status , and concomitant anorectal disorders of each woman . the women were interviewed on the presence of emptying symptoms , and completed the bfluts questionnaire [ table 1 ] , which is systematic in our department . we screened for five items related to voiding difficulties : hesitancy , slow or intermittent stream , straining , or sensations of incomplete emptying . for the purposes of data analysis , those women who answered  never  to all five items were classed in the non - vds group . those women for whom one or more of the answers was positive ( i.e. :  occasionally , sometimes , most of the time or all the time  ) , were classified in the vds group . the clinical examination included a physical examination , urodynamic testing and a  free flow  uroflowmetry and filling cystometry at a rate of 50 ml per minute ( duet , medtronic ) . the filling cystometry parameters studied were : compliance , detrusor overactivity ( do ) , detrusor sensation . none of the patients presented with abnormal compliance , do , or abnormal detrusor sensation . both a quantitative and a qualitative analysis of bladder outlet obstruction ( boo ) was made by uroflowmetry . quantitatively , a patient was considered to have boo when a maximum flow rate of less than 15 ml / sec was observed for a urine volume greater than 200 ml , and/or the post - void residual was greater than 50 ml , as measured with a bladder scan or by catheterization . the urine flow was also analyzed in terms of average flow rate , urine volume , voiding time and acceleration ( defined as the maximum flow rate divided by the time taken to reach maximum flow rate ) . the qualitative analysis dealt with the flow patterns : a standard  bell - shaped three pathologic patterns were considered : intermittent or continuous polyphasic curves , and flat curves [ figures 1a  c ] . we determined the sensitivity and specificity as well as the positive and negative predictive value of the vds questionnaire using the uroflowmetry data . ( a ) intermittent polyphasic curve ( b ) continuous polyphasic curve ( c ) flat curve a comparison of the clinical characteristics and uroflowmetry of the two groups was made using a wilcoxon test for continuous data and a fischer test for categorical data . as the bfluts questionnaire and urodynamics were identical to those systematically used for the routine evaluation of sui women in our department , the study did not require specific ethics committee approbation . among the 93 women eligible for the study , 61% ( 57/93 ) complained of vd symptoms on the bfluts questionnaire ( vds group ) and 39% ( 36/93 ) had no vd symptoms ( non - vds group ) . patients characteristics are detailed in table 2 . no difference was observed between the two groups concerning age , parity , menopausal status , concomitant anorectal disorders and uroflowmetry parameters . in the vds group , 75% ( 27/36 ) of the women in the non - vds group had normal uroflowmetry , and 25% ( 9/36 ) an abnormal one without symptoms . the positive predictive value of the vds questionnaire was 32% and the negative predictive value was 75% [ table 3 ] . there was no statistical correlation between symptoms and the defined criteria of boo on uroflowmetry ( fischer test : p=0.64 ) . among the 42 women who complained of a sensation of incomplete emptying , only one had a real post - void residual greater than 50 ml . in this sui population without severe pelvic organ prolapse ( baden and walker staging system 1 ) , previous sui surgery , or neurological disorders ( the most frequent etiologies of voiding dysfunction in women ) we found a 29% ( 29/93 ) rate of abnormal uroflowmetry . characteristics of women with and without voiding difficulties symptoms in terms of age , menopausal status , parity , anorectal disorders and uroflowmetry parameters sensitivity , specificity , positive and negative predictive value of voiding dysfunction symptoms on bfluts multivariate analysis ( using multiple logistic regression method ) demonstrated no correlation between symptoms and quantitative uroflowmetry parameters ( maximum and average flow rate , acceleration , urine volume , time to maximum flow and voiding time ) , and no correlation was found between vds and age , menopausal status , parity or concomitant anorectal disorders [ table 4 ] . logistic regression method for multivariate analysis of urodynamic parameters ( maximal and average flow rate , time to void and acceleration ) , age , menopausal status , parity , concomitant anorectal disorders with respect to voiding difficulties symptoms univariate analysis of multiple factors with respect to voiding difficulties symptoms our results show that 25% of sui women without obstructive symptoms , i.e. without an obvious cause for bladder outlet obstruction ( no severe genital prolapse ( > grade 1 ) ) , having had no previous surgery for sui , and with no neurological disorders , have an abnormal uroflowmetry , and thus a higher risk of post - surgery obstructive disorders . our study clearly demonstrates the poor predictive value of the vds questionnaire , when compared with urodynamic data . the prevalence of voiding dysfunction symptoms among women is not easy to determine , in contrast to storage symptoms , which are more often related and analyzed . stress urinary incontinence and bladder outlet obstruction ( boo ) can coexist in women ; bradley found 19 cases of boo out of 104 ( 18% ) , defined on the basis of pressure flow studies among women presenting with sui . in our study , we found a high prevalence of vds ( 61% ) , probably because in the vds group we included women with any level of positive response , even those who gave one  occasionally response to the vd items ( bfluts questionnaire ) . urodynamic evaluation of the voiding phase in sui women before surgery is useful in order to predict the risk of vd and urinary retention , and to inform women about these potential complications . surgical treatments of sui using mid - urethral sling procedures are known to affect the voiding phase : the spontaneous flow curve changes to a more obstructive pattern in 40% of cases , and the maximum and mean flow rates decrease significantly after one year . the incidence of urinary retention after such procedures ranges from 2.216%.[13 ] postoperative vd induces a decrease in global satisfaction after surgery , and leads to an impairment of the quality of life . factors which correlate highly with a postoperative voiding dysfunction include a preoperative peak flow rate < 15 ml / s ( several studies ) , and an abnormal uroflow pattern or detrusor pressure < 12 cm h2o.[31114 ] therefore , screening for such factors among sui women is critical . one of the main limitations of the current study is the lack of a standard definition for boo in urodynamics for women . since voiding cystometry had not been performed , boo can not be defined urodynamically in the current study . farrar et al . , defined obstruction as qmax < 15 ml / s with a voided volume of 200 ml . we added the flow curve pattern criteria , because a pathological pattern with a normal maximal flow rate can reflect voiding difficulties . moreover , in pressure flow studies in women , the transurethral catheter has a significant impact on the urine flow.[1418 ] however ,  free flow uroflowmetry is a composite interaction between the detrusor pressure and the resistance produced by the urethra . bladder outlet obstruction as well as impaired detrusor contractility can perturb uroflowmetry . in our population , we needed to detect voiding difficulties , whatever their origin , because among sui women both these causes of voiding disorders can promote obstructive complications after surgery . chassagne et al . , prospectively studied 35 clinically obstructed women and 124 control patients . they determined cutoff values for the pressure flow studies as : qmax<15 ml / s and pdet . qmax > 20 cm h2o , with a sensitivity of 74.3% and a specificity of 91.1% . no information was provided regarding the clinical criteria used to select the  clinically obstructed  patients . qmax > 20 cm h2o ) during detrusor pressure uroflow studies . among the 38 women considered as obstructed within this definition , they concluded that micturition symptoms relevant to bladder outlet obstruction are non - specific , and that a complete urodynamic evaluation is essential . the correlation between obstructive symptoms and objective urodynamic findings is known to be poor , but has never been studied in this specific population of sui women , for which all cases with a pop - q > stage 1 , previous surgery for sui , or neurological disorders , were excluded . indeed , we excluded the most common etiologies of urodynamic assessment of bladder outlet obstruction . groutz et al . , reported 26% of prior anti - incontinence surgery and 24% of severe genital prolapse in a population of 38 women presenting with urodynamically assessed obstructive criteria . wyndaele et al . , recently confirmed the poor correlation between symptoms and urodynamic data , and a high prevalence of vds in women , whether it be considered to have a pathological origin or not . the absence of voiding symptoms is not a guarantee of normal micturition , since we found that almost one - third of the women not complaining of any voiding difficulty were actually shown to have an abnormal uroflowmetry . previous studies[1421 ] have clearly demonstrated the lack of correlation between symptoms and urodynamic diagnoses , especially for obstructive symptoms . we found the same results , but in a particular population of sui women , with no obvious reasons for obstruction . even in this selected population , in which voiding dysfunctions should be less frequent than in the general population , we found that almost 30% of the patients had an abnormal uroflowmetry . no correlation was found between obstructive symptoms and boo as defined on uroflowmetry , in a specific population of sui women .
objectives : to determine whether the completion of a voiding dysfunction ( vd ) questionnaire could have a good predictive value for uroflowmetry findings , in a population of stress urinary incontinence ( sui ) women.materials and methods : from a urodynamic database of 415 sui women , 93 with isolated sui who underwent urodynamic investigations were eligible for this study . 
 patients with obvious etiologies of obstruction were excluded . 
 vd symptoms were analyzed using the bristol female lower urinary tract symptoms questionnaire . 
 bladder outlet obstruction ( boo ) was defined as a maximal flow rate under 15 ml / s for a urine volume > 200 ml , or a post - void residual volume greater than 50 ml , or an abnormal pattern of the flow curve . 
 the sensitivity , specificity , positive and negative predictive value of questioning vd were calculated . 
 statistical analysis was done using a wilcoxon test for continuous data and fisher exact test for categorical data , and multivariate analysis.results:reported vd had a poor specificity ( 41% ) and positive predictive value ( 32% ) of boo on uroflowmetry . 
 no statistical correlation was found between vd symptoms and boo defined on uroflowmetry ( p=0.64 ) in this specific sui population showing no obvious etiologies of obstruction.conclusions:no correlation was found between obstructive symptoms and boo as defined on uroflowmetry , in a specific population of sui women . 
 our results suggest that uroflowmetry may be necessary rather than multichannel urodynamics .