aid in identifying women with outflow obstruction. J Urol, 163:1823, 2000

7. Blaivas, J. G. and Groutz, A.: Bladder outlet obstruction nomo-gram for women with lower urinary tract symptomatology.Neurourol Urodyn, 19: 553, 2000

8. Cormier, L., Ferchaud, J., Galas, J.-M., Guillemin, F. andMangin, P.: Diagnosis of female bladder outlet obstruction andrelevance of the parameter area under the curve of detrusorpressure during voiding: preliminary results. J Urol, 167:2083, 2002

9. Groutz, A., Blaivas, J. G. and Sassone, A. M.: Detrusor pressureuroflowmetry studies in women: effect of a 7Fr transurethralcatheter. J Urol, 164: 109, 2000

EDITORIAL COMMENTS

The topic of BOO in women recently has generated much interestand debate with growing awareness that this phenomenon may bemore common in women with diverse lower urinary tract symptomsthan once previously believed. In the current study the authorsselected women found to have SUI during video urodynamics(VUDS) and using previously identified parameters they determinedthe incidence of BOO. Interestingly they found the incidence to behigher (18%) than one might normally expect in a group of stressincontinent women, a finding that the authors attributed to thenature of their tertiary referral practice, which certainly seems likelyto be the case, at least in part.

These findings are particularly intriguing in light of the findingthat others have previously reported lower voiding pressures inwomen with urodynamically determined SUI compared with conti-nent women.1 Our observation was that women with SUI were foundto have detrusor pressures at maximum flow that were significantlylower (16 cm water) than women without urinary symptoms (24 cmwater) and only 1 with SUI had pressure flow values in the ob-structed range.2 Interestingly this value for stress incontinentwomen is quite close to the value reported by the authors (15 cmwater) for women with SUI and normal voiding dynamics. While it isnot entirely clear what accounts for this difference from 2 academicreferral centers, I suspect that the difference lies in the symptoms ofthe patients included.

Because the authors obtained their group from surveying theurodynamic data base for women with SUI during VUDS, it is notclear that SUI was the primary symptom, as the authors allude to inthe final paragraph. It seems likely that many women would havesymptoms other than simply SUI and perhaps SUI was an unex-pected (and potentially less meaningful) finding during VUDS. Itwould be interesting to know how many desired and received treat-ment for SUI. Also, it is unknown if the presence of BOO shouldaffect the treatment plan or advice offered for SUI. Had the authorsonly included patients whose primary symptom was SUI I suspectthat the incidence of BOO would have been appreciably lower, aswould the corresponding voiding pressures.

Lastly, as the authors note, they used flow values from intubatedstudies to derive the incidence of BOO. While the presence of thecatheter clearly affects flow rates, one also wonders whether patientsunable to void during VUDS (5 of the 19 who were deemed ob-structed) are truly obstructed or more likely was it an artifact of thestudy. It is precisely these patients in whom a nonintubated study isnecessary to ensure a proper diagnosis of BOO (reference 9 in article).

Regardless, the authors raise an interesting and valid point, whichis that BOO and SUI can coexist. While it seems unlikely that manypatients primarily reporting SUI may be found to have obstruction,the fact that the 2 conditions can be present should not be over-looked. From a practical standpoint it is hoped that further evalua-tion of these women would allow us to determine if the presence ofBOO adversely affects treatment outcome, particularly in those whoelect surgical therapy.

Gary E. LemackDepartment of UrologyUniversity of TexasSouthwestern Medical CenterDallas, Texas

1. Karram, M. M., Partoll, L., Bilotta, V. and Angel, O.: Factorsaffecting detrusor contraction strength during voiding inwomen. Obstet Gynecol, 90: 723, 1997

2. Lemack, G. E., Baseman, A. G. and Zimmern, P. E.: Voidingdynamics in women: a comparison of pressure flow studies

between asymptomatic and incontinent women. Urology, 59:42, 2002

The authors show that urodynamic obstruction can exist in womenwho also have SUI. In their cohort 18% of 104 women with stressincontinence had urodynamic evidence of obstruction, as defined bythe authors. Several of these patients had conditions in which stressincontinence and anatomical or functional BOO are known to exist,for example after incontinence surgery, in neurological disease andin prolapse. They accounted for more than half of the patients. Inaddition, 3 patients had dysfunctional voiding and SUI. These 2phenomena have also been reported to occur together.1 The 5 pa-tients in whom obstruction was idiopathic are an interesting group.We do not know why they were obstructed and how obstructioninfluenced the treatment of stress incontinence.

The authors demonstrate that the phenomena of obstruction andstress incontinence can exist together. However, there are someshortcomings of the study that the authors themselves admit. First,subjects were examined in the standing position. It is not a normalposition for women to void in and, thus, it may have influencedpressure flow dynamics. Previous studies that defined BOO inwomen defined it with women in the sitting position. It is not knownhow the standing position affects voiding dynamics. Second, becauseit was a retrospective study, we do not know how many of thesepatients had clinically obstruction. It is well known that there areartifacts that can occur during urodynamic testing that affect thepressure flow analysis. If obstruction was not suspected in a partic-ular patient, further testing may have been done, such as noninva-sive uroflowmetry. We have come to rely greatly on noninvasiveuroflowmetry to provide information in addition to the pressure flowstudy. We still believe in using detrusor pressure and flow rate fromthe pressure flow study and not necessarily using a free flow rate, asdescribed by Blaivas and Groutz (reference 7 in article). However,noninvasive flow can provide useful information, especially in ensur-ing that the flow pattern during urodynamic testing was indeed atrue flow pattern. Thus, it is possible that not all of the 19 patientswho were deemed obstructed during urodynamic testing actuallywere obstructed. Nevertheless, I am certain that some of them wereand the authors show that these 2 phenomena can exist according tourodynamic criteria.

Victor W. NittiNew York University Urology AssociatesNew York, New York

1. Carlson, K. V., Rome, S. and Nitti, V. W.: Dysfunctional voidingin adult female. J Urol, 165: 143, 2001

In this study the authors identify the coexistence of BOO in 18.3%of women who have urodynamic evidence of SUI. They started witha cohort of women with SUI and used detrusor pressure and uro-flowmetry to select patients with BOO. Patients with a urinary flowrate of less than 12 ml per second or no flow and a detrusor pressureat maximum flow of greater than 20 cm water were identified ashaving coexisting BOO. The etiology of the BOO included priorsurgery, neurogenic disease, cystocele and dysfunctional voiding. Itis interesting to note that in 26% of the patients with obstruction anetiology was not identified. As stated by the authors, there are somelimitations to the method of data acquisition. In all probability itreflects our lack of understanding of obstructed voiding in women. Inthese patients voiding dynamics may have been altered by studyingwomen in the standing position. Most women void sitting and, thus,it is probably preferable to study them in the sitting position. Also,the only use of the urodynamic data base did not encompass acomparison of symptoms or physical examination findings. In a se-ries of patients undergoing repeat urethrolysis Scarpero et al notedthat the temporal relationship of voiding dysfunction after an anti-incontinence procedure was most important for achieving a diagnosisof obstruction.1 Perhaps women after anti-incontinence procedureswho had symptoms of obstruction but not the pressure flow profile ofobstruction could have been excluded from these data. It has alsobeen reported that symptoms alone can be unreliable for predictingobstruction (reference 3 in article), particularly in women with dys-functional voiding. The lack of a clear consensus on how to diagnosebladder outlet obstruction is the major limitation to studying thisissue.

Despite these issues one should not underestimate the implica-tions of this series. Women who present with SUI may have concom-itant dysfunction of bladder emptying. There is currently consider-

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