REVIEW URRENT C OPINION
Modern evaluation of lower urinary tract symptoms in 2014 Altaf Mangera and Christopher Chapple
Purpose of review To evaluate and present the evidence for the use of different investigation modalities in men with benign prostatic hyperplasia/lower urinary tract symptoms (LUTS) in 2014. Recent findings Cystometry remains the gold standard in differentiating obstructed from nonobstructed men with LUTS. Prostatic ultrasound measures such as the intravesical prostatic protrusion may be useful in counselling men before a trail without catheter or commencing a antagonists. Using a higher cut-off, the bladder thickness/ weight measurement has a higher sensitivity but lower specificity and may allow men with obstruction to be excluded from requiring cystometry. These and other techniques such as near-infrared spectroscopy, penile cuff compression and computational flow modelling have shown good correlation with cystometry but still require more data, technical refinement and standardization, before they can be considered to be appropriate in routine clinical practice. Summary The last few years have seen an increase in the data regarding less invasive methods of cystometry. Although these do not provide the same information as cystometry, they may have a role in answering specific questions and counselling men with benign prostatic hyperplasia/LUTS. The key to incorporating these techniques in the assessment of men will lie with standardization and use for specific indications. Keywords bladder outflow obstruction, computational flow modelling, cystometry, infrared spectroscopy, intravesical prostatic protrusion, penile cuff compression, resistive index, urodynamics
INTRODUCTION
PROSTATE IMAGING
It is without doubt that uroflowmetry is useful in the assessment of men with lower urinary tract voiding symptoms (LUTS). However, a simple flow rate lacks the ability to differentiate obstructed (high pressure, low flow) voiding from detrusor underactivity (low pressure low flow). This distinction is significant, as those men without obstruction are less likely to be benefitted by prostatic surgery. This is where cystometry may be beneficial. This procedure is, however, invasive, costly and timeconsuming. It is probably not required in all men with an enlarged prostate, voiding symptoms and a classical flow rate pattern. However, its use in equivocal cases, mixed symptoms, failed surgery and chronic retention is less disputed. This review will explore the new less-invasive techniques being developed as a potential alternative to conventional cystometry.
The prostate volume as measured with ultrasound has been shown to correlate poorly with symptoms of bladder outflow obstruction (BOO). The transitional zone size, which is predominantly affected by benign enlargement, has also not shown good correlation with urodynamic findings [1]. The resistive index in the prostatic arteries may be measured via colour Doppler. The theory behind this measure is that the larger transitional zone compresses the prostatic arteries against the capsule Sheffield Teaching Hospitals, Glossop Road, Sheffield, UK Correspondence to Christopher Chapple, MD, Consultant Urological Surgeon, Sheffield Teaching Hospitals, Glossop Road, Sheffield S10 2 JF, UK. Tel: +44 114 271 2559; fax: +44 114 279 7841; e-mail: [email protected] Curr Opin Urol 2014, 24:15–20 DOI:10.1097/MOU.0000000000000013
0963-0643 ß 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins
www.co-urology.com
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Benign prostatic hyperplasia
KEY POINTS Pressure flow cystometry remains the gold standard investigation modality for men with benign prostatic hyperplasia (BPH)/LUTS. The use of prostate ultrasound measures may be useful in deciding whether medical therapy may be beneficial. Detrusor thickness and weight assessment still requires better standardization and needs to be assessed in different populations. NIRS has a high specificity for obstruction but requires expertise in assessment and interpretation. The penile cuff test may be useful in deciding which men are obstructed and suitable for surgery but is less useful in excluding unobstructed men who may then need to progress to formal urodynamics.
thus reducing flow. The resistive index is calculated transrectally based on the peak systolic velocity – end diastolic velocity/peak systolic velocity. The resistive index has been reported to have a sensitivity of 78% and specificity of 86% for diagnosing BOO [2 ]. One study in 572 men showed the area under the receiveroperating characteristic (ROC) curve to be 0.87, which was higher than the transitional zone index and total prostate volume in predicting an effective outcome after transurethral resection of prostate (TURP) [3]. Another study in 239 men showed an area under the curve (AUC) of 0.816, which was better than that for bladder wall thickness (BWT) and ultrasound-estimated bladder weight [4 ]. The resistive index is affected by diabetes, arteriosclerosis and medications and can be operator-dependent. These limitations still need further investigation. Intravesical prostatic protrusion has also been investigated [5]. If the length of prostate protrusion from its base is greater than 10 mm, then it has been shown that a blockers may be ineffective [6 ,7 ], and surgery is likely to be more effective [8]. A recent study has reported an AUC of 0.71 for predicting BOO symptoms [9 ]. Another study reported an AUC compared with the BOO index of 0.84 [10]. Also, there is a higher likelihood of trail without catheter (TWOC) failure in men with acute urinary retention if the intravesical prostatic protrusion (IPP) is greater than 10 mm [11]. The prostatic urethral angle occurs between the membranous and prostatic urethra. When correlated with the bladder outflow obstruction index (BOOI), the area under the ROC curve was 0.63 in one study [12]. An angle of greater than 35 degrees was shown to correlate with BOO, but an increasing angle did not correlate with the degree of BOO. &
&&
&
&
16
www.co-urology.com
&
The limitations of the above studies are that they arise from the notion of prostatic obstruction and cannot inform upon bladder contractility. If detrusor compensation or decompensation has occurred secondary to prostatic obstruction, or in cases of detrusor underactivity, these studies will in theory not be useful in deciding who is likely to benefit from outflow obstruction surgery. Also, the conditions for the above measures are not fully standardized and parameters such as comorbidity and bladder volume during assessment need to be defined. However, their utility may be in deciding which men are at risk for progression and may benefit from early treatment.
BLADDER THICKNESS/WEIGHT BWT and detrusor wall thickness (DWT) may be measured via ultrasound. BWT has been suggested to correlate less with BOO than DWT, as the mucosal layer of the bladder may be affected by other pathologies and it is the detrusor that is most affected by BOO [13]. This may explain why there is some discrepancy in the reports correlating BWT with pressure flow studies. Manieri et al. [14] showed a significant correlation (r > 0.6) with a cut-off of 5 mm, with 63% of men with a thickness less than this being unobstructed and 88% above this being obstructed. However, Hakenberg et al. [15] showed that BWT increases slightly with age and the cut-off for men with BPE was only 0.3 mm greater than men without symptoms. Another parameter shown to affect BWT is BMI [16 ]. Blatt et al. [17] also found no correlation in BWT with urodynamic studies in non-neurogenic patients with a multitude of symptoms. Women with detrusor overactivity have been shown to have a higher BWT compared with those without detrusor overactivity, as it has been suggested that detrusor overactivity against a closed urethra may lead to detrusor hypertrophy [18]. Another study reported a significant reduction in BWT after the use of tamsulosin for 2 months, although the actual reduction was small at 0.77 mm [19]. Oelke et al. have prospectively compared anterior DWT more than 2 mm with a 7.5-MHz ultrasound at functional bladder capacity to standard urodynamics. The technique had a sensitivity of 83%, specificity of 95%, positive and negative predictive values of 94% and 86%, respectively [20]. The AUC for DWT was found to be 0.723 for successful TURP in 239 men [4 ]. DWT decreases continuously with increasing bladder filling up to only 250 ml, but thereafter remains stable until maximum bladder capacity. Interobserver variability has been reported at 4–12.3% [21], but the majority &&
&&
Volume 24 Number 1 January 2014
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Modern evaluation of LUTS in 2014 Mangera and Chapple
may be the result of technical variations such as bladder filling volume, region of measurement and frequency of ultrasound probe [22]. Other problems with this technique are that minimal changes need to be interpreted that is less than 2 mm. Kessler et al. have reported a 100% sensitivity and positive predictive value with a higher cut-off of more than 2.9 mm, but this led to a lower specificity of 43% and negative predictive value of 54% in a study of 102 men [21]. Using a higher cut-off may at least allow the inclusion of men most likely to benefit from surgery, whereby those excluded may then progress to cystometry. The ultrasound estimated bladder weight (UEBW) is a technique that is proposed to overcome the influence of bladder-filling volume [23]. This is calculated from the thickness of the bladder wall and the intravesical volume, assuming a spherical bladder. The UEBW was shown in one study to correlate poorly with Qmax [24] but correlated well with bladder weight excised at autopsy [23]. The AUC for UEBW for patients who had a successful TURP was found to be 0.723 [4 ]. The cut-off proposed to correlate with pressure flow studies is 35 g [25–27]. Kojima et al. [25] showed in 65 men that this had a diagnostic accuracy of 86% for BOO. Another study showed that men were 13 times more likely to develop acute urinary retention if above this cut-off and had an area under the ROC curve of 0.8 [26]. Interestingly, post prostatectomy, the UEBW has been shown to reduce from 53 to 32 g [28]. It must be noted that all these studies are in Japanese men and therefore may not be transferrable to other populations. In South American and European men, a correlation between UEBW and BOO has not been found [24,29]. In healthy volunteers, the UEBW has been shown to be influenced by height and body surface area [30]. Therefore Han et al. [31] have shown that the diagnostic accuracy of UEBW may be enhanced by correction for body surface area with a sensitivity of 62% and specificity of 83%.
with a specificity of 88% for NIRS compared with pressure flow studies [33]. Similarly, another study, by a different group, has reported a sensitivity of 86.2% and specificity of 87.5% [34 ]. More recently, a wireless NIRS monitor has been shown to lead to comparable results [35 ]. Problems with NIRS are that motion artefact and abdominal straining may affect readings, obesity may make readings difficult, there is still considerable intra-patient variability and there are technical failures [32,36]. In addition, patients with chronic health conditions (vascular disease, renal failure and so on) have been excluded from one study [34 ] and the study by Stothers et al. [33] did not include any diabetes patients. One study in the literature showed poor correlation between urodynamics and NIRS with an AUC of 0.48 [37]. However, the algorithm utilized in this study has subsequently been improved [33]. It was suggested that NIRS may be useful also in assessing detrusor overactivity [38]; however, a recent study has shown poor sensitivity and specificity for this [39]. &
&
&
&&
NEAR-INFRARED SPECTROSCOPY This technique measures concentration of oxyhaemoglobin and deoxyhaemoglobin levels in tissue. Increased work by the detrusor muscle (as occurs in BOO) leads to a reduction in oxyhaemoglobin levels (downward slope), whereas in an unobstructed system, oxyhaemoglobin levels increase (upward slope). When applying a customized algorithm utilizing the Qmax, post void residual and NIRS, MacNab et al. [32] were able to correctly identify 86% of men as obstructed or unobstructed. Another study reported misclassification of BOO in only 4%
CONDOM CATHETER METHOD A sheath modified with a pressure transducer, which measures the isovolumetric pressure (Pves.iso), is worn over the penis. The Pves.iso is the pressure generated by the contracting bladder against a closed bladder outlet. The patient is asked to initiate voiding and the flow out of the condom is interrupted several times. This therefore allows the determination of maximum intravesical pressure. The urethral resistance may be calculated from the maximum condom pressure and the Qmax. The recorded pressures are significantly higher in nonobstructed patients [40,41]. Pressures should ideally be recorded with bladder volumes above 247 ml, as below this they are less accurate [42]. In addition, the flow rate needs to be more than 5.4 ml/s to allow adequate flow for interruption. Other problems include failed measurement because of leaking and urethral closure because of straining. Repeatability similar to pressure flow studies has been shown with a success rate of 94% [43,44]. Correct categorization of men into obstructed and nonobstructed categories was found in 42 of 46 patients with reference to urodynamics [41].
PENILE CUFF TEST A pneumatic cuff is placed around the penis and with cuff inflation the flow is interrupted. The pressure of the fluid column in the urethra is equated to the intravesical pressure assuming a continuous fluid column connecting both points. Two methods of measurement have been described. The deflation
0963-0643 ß 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins
www.co-urology.com
17
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Benign prostatic hyperplasia
techniques involve inflation of the cuff, followed by permission to void against a closed cuff and the cuff is released when the patient feels urine in the urethra [45]. With the interruption technique, voiding is halted mid flow and then the cuff is deflated rapidly resulting in a surge of urine (Qsurge), followed by steady state flow (Qss) [46]. This cycle may be repeated multiple times. The penile compression release index is calculated as (Qsurg Qss)/Qss. The estimation of intravesical pressure has been shown to be 15 cmH2O higher than standard cystometry, which has been put down to the cuff being placed below bladder height [47]. In addition, good reproducibility and interobserver agreement has been shown on repeat testing especially if voided volumes are more than 150 ml [47,48]. The maximum value of cuff interruption pressure plotted on a noninvasive pressure flow nomogram has been proposed to provide the best diagnostic accuracy [49]. A positive predictive value of 82% and a negative predictive value of 88% have been reported [50 ]. More interestingly, men deemed to be obstructed by the penile cuff test had an 87% chance of a good outcome after TURP compared with only 56% who were deemed obstructed [51]. This differentiation may be useful in excluding men who are obstructed and therefore do not need invasive urodynamics. There are a few limitations, such as a high trace exclusion rate due to technical problems, abdominal straining is unaccounted for and there is a high equivocal outcome rate in which patients have a success of 78% following TURP [51]. More recently, a continuous penile compression technique has been described that slows the flow down to 2.5 ml/s [52]. The authors have reported good agreement between cuff and intravesical pressures throughout the void. Although promising, there are no correlations with pressure flow studies to date. &
COMPUTATIONAL MODELLING OF FLOW The shape or wave pattern made by the urine stream exiting the urethral meatus may contain diagnostic information regarding voiding. The liquid jet exiting a noncylindrical aperture deforms under surface tension forces. High-speed cinematography may demonstrate the urine stream break into drops on exiting the urethral meatus. In the drop spectrometer, the stream is passed through a horizontal beam, which is deflected by each drop and the light is detected by a photodetector [53]. It is proposed that the shape and speed of the drops in the stream may give an indication of detrusor pressure. However, the limitation with this thus far has been the correction required for individuals’ urethral geometry [54 ]. &
18
www.co-urology.com
Doppler ultrasound may be used to assess flow through the prostatic urethra. Flow velocity curves can be created at the distal prostatic urethra and at the membranous urethra with reasonable inter-rater reliability [55]. In men with BOO, the ratio of the Qmax/maximum velocity is lower. The ratio of the maximum velocities at the two sites correlates with obstruction with a Spearman’s rho of 0.7 [56]. A velocity ratio more than 1.6 correctly classified 22 men as obstructed according to pressure flow criteria. The limitations of this procedure are cost, specialization is required to take the recordings and the measurements are performed seated (most men void standing).
HISTOLOGICAL ASSESSMENT OF DETRUSOR FUNCTION It has been shown that detrusor hypertrophy may occur secondary to BPO. This has been correlated to histological findings, which showed increased connective tissue relative to smooth muscle [57,58]. Elbadawi et al. [59] have shown that those with urodynamically proven obstruction had myohypertrophy with wide spaces between muscle cells. Conversely, those who were unobstructed showed degeneration of muscle cells and axons. More recently, it has been shown that parts of the detrusor muscle degenerate and are eliminated. Thereafter, compensatory hypertrophy of the remaining cells with replacement fibrosis occurs [60]. It has been suggested that knowing the histological make-up of detrusor muscle may be able to predict detrusor underactivity; however, correlative studies are still required to show this.
CONCLUSION Despite advances in technology and research, pressure flow studies still remain the gold standard in differentiating obstructed from nonobstructed men. There may be some utility in using IPP to decide whether men will benefit from a blockers and should undergo surgery earlier. The other techniques still require refinement and evaluation in wider populations with better standardization. Acknowledgements None. Conflicts of interest C.C. is a Speaker for Ranbaxy, Consultant for AMS, Lilly and ONO, and Consultant, Researcher, Speaker and Trial Participation for Allergan, Astellas, Pfizer and Recordati. Volume 24 Number 1 January 2014
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Modern evaluation of LUTS in 2014 Mangera and Chapple
REFERENCES AND RECOMMENDED READING Papers of particular interest, published within the annual period of review, have been highlighted as: & of special interest && of outstanding interest
1. Witjes WP, Aarnink RG, Ezz-el-Din K, et al. The correlation between prostate volume, transition zone volume, transition zone index and clinical and urodynamic investigations in patients with lower urinary tract symptoms. Br J Urol 1997; 80:84–90. 2. Zhang X, Li G, Wei X, et al. Resistive index of prostate capsular arteries: & a newly identified parameter to diagnose and assess bladder outlet obstruction in patients with benign prostatic hyperplasia. J Urol 2012; 188:881– 887. This study shows that resistive index has a sensitivity of 78% and specificity of 86% in men with BOO. 3. Shinbo H, Kurita Y, Nakanishi T, et al. Resistive index: a newly identified predictor of outcome of transurethral prostatectomy in patients with benign prostatic hyperplasia. Urology 2010; 75:143–147. 4. Huang T, Qi J, Yu YJ, et al. Predictive value of resistive index, detrusor wall && thickness and ultrasound estimated bladder weight regarding the outcome after transurethral prostatectomy for patients with lower urinary tract symptoms suggestive of benign prostatic obstruction. Int J Urol 2012; 19:343– 350. This study investigated IPP, resistive index, DWT and UEBW via ultraosund in 239 patients. When compared with success after TURP ,the resistive index, DWT and UEBW showed good correlation with the resistive index having the greatest AUC. This is the only study to date to compare a range of techniques and therefore could also assess the combination of these techniques, which improved the positive predictive value to 96%. 5. Lieber MM, Jacobson DJ, McGree ME, et al. Intravesical prostatic protrusion in men in Olmsted County, Minnesota. J Urol 2009; 182:2819–2824. 6. Cumpanas AA, Botoca M, Minciu R, Bucuras V. Intravesical prostatic protru& sion can be a predicting factor for the treatment outcome in patients with lower urinary tract symptoms due to benign prostatic obstruction treated with tamsulosin. Urology 2013; 81:859–863. This study questions the use of a blockers in men with IPP greater than 10 mm. This is useful when deciding which men should receive a TWOC and who should proceed to surgery. 7. Seo YM, Kim HJ. Impact of intravesical protrusion of the prostate in the & treatment of lower urinary tract symptoms/benign prostatic hyperplasia of moderate size by alpha receptor antagonist. Int Neurourol J 2012; 16:187– 190. Similar to above study, IPP may be used to define which men may benefit from a blockers. 8. Lee JW, Ryu JH, Yoo TK, et al. Relationship between intravesical prostatic protrusion and postoperative outcomes in patients with benign prostatic hyperplasia. Korean J Urol 2012; 53:478–482. 9. Aganovic D, Hasanbegovic M, Prcic A, et al. Which is a better indicator of & bladder outlet obstruction in patients with benign prostatic enlargement– intravesical protrusion of prostate or bladder wall thickness? Med Arh 2012; 66:324–328. Thus study shows that IPP correlates better with BOOI than BWT. 10. Franco G, De NC, Leonardo C, et al. Ultrasound assessment of intravesical prostatic protrusion and detrusor wall thickness–new standards for noninvasive bladder outlet obstruction diagnosis? J Urol 2010; 183:2270– 2274. 11. Syazarina SO, Zulkifli MZ, Hamzaini AH. Predicting outcome of trial of voiding without catheter in acute urinary retention with intravesical prostatic protrusion. Malays J Med Sci 2013; 20:56–59. 12. Ku JH, Ko DW, Cho JY, Oh SJ. Correlation between prostatic urethral angle and bladder outlet obstruction index in patients with lower urinary tract symptoms. Urology 2010; 75:1467–1471. 13. Bright E, Oelke M, Tubaro A, Abrams P. Ultrasound estimated bladder weight and measurement of bladder wall thickness–useful noninvasive methods for assessing the lower urinary tract? J Urol 2010; 184:1847– 1854. 14. Manieri C, Carter SS, Romano G, et al. The diagnosis of bladder outlet obstruction in men by ultrasound measurement of bladder wall thickness. J Urol 1998; 159:761–765. 15. Hakenberg OW, Linne C, Manseck A, Wirth MP. Bladder wall thickness in normal adults and men with mild lower urinary tract symptoms and benign prostatic enlargement. Neurourol Urodyn 2000; 19:585–593. 16. Bright E, Pearcy R, Abrams P. Automatic evaluation of ultrasonography&& estimated bladder weight and bladder wall thickness in community-dwelling men with presumably normal bladder function. BJU Int 2012; 109:1044– 1049. This study revealed that the bladder weight correlated with patient weight, BMI and filling volume more than IPSS socres in 100 male volunteers. 17. Blatt AH, Titus J, Chan L. Ultrasound measurement of bladder wall thickness in the assessment of voiding dysfunction. J Urol 2008; 179:2275–2278.
18. Khullar V, Cardozo LD, Salvatore S, Hill S. Ultrasound: a noninvasive screening test for detrusor instability. Br J Obstet Gynaecol 1996; 103:904– 908. 19. Eghbali K, Shayegan MR, Kianoush S. Investigating the effect of tamsulosin on the measurement of bladder wall thickness and International Prostate Symptom Score in benign prostatic hyperplasia. Can Urol Assoc J 2013; 7:E317–E321. 20. Oelke M, Hofner K, Jonas U, et al. Diagnostic accuracy of noninvasive tests to evaluate bladder outlet obstruction in men: detrusor wall thickness, uroflowmetry, postvoid residual urine, and prostate volume. Eur Urol 2007; 52:827– 834. 21. Kessler TM, Gerber R, Burkhard FC, et al. Ultrasound assessment of detrusor thickness in men-can it predict bladder outlet obstruction and replace pressure flow study? J Urol 2006; 175:2170–2173. 22. Oelke M. International Consultation on Incontinence-Research Society (ICI-RS) report on noninvasive urodynamics: the need of standardization of ultrasound bladder and detrusor wall thickness measurements to quantify bladder wall hypertrophy. Neurourol Urodyn 2010; 29:634–639. 23. Kojima M, Inui E, Ochiai A, et al. Ultrasonic estimation of bladder weight as a measure of bladder hypertrophy in men with infravesical obstruction: a preliminary report. Urology 1996; 47:942–947. 24. Bright E, Pearcy R, Abrams P. Ultrasound estimated bladder weight in men attending the uroflowmetry clinic. Neurourol Urodyn 2011; 30:583– 586. 25. Kojima M, Inui E, Ochiai A, et al. Noninvasive quantitative estimation of infravesical obstruction using ultrasonic measurement of bladder weight. J Urol 1997; 157:476–479. 26. Miyashita H, Kojima M, Miki T. Ultrasonic measurement of bladder weight as a possible predictor of acute urinary retention in men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia. Ultrasound Med Biol 2002; 28:985–990. 27. Akino H, Maekawa M, Nakai M, et al. Ultrasound-estimated bladder weight predicts risk of surgery for benign prostatic hyperplasia in men using alphaadrenoceptor blocker for LUTS. Urology 2008; 72:817–820. 28. Kojima M, Inui E, Ochiai A, et al. Reversible change of bladder hypertrophy due to benign prostatic hyperplasia after surgical relief of obstruction. J Urol 1997; 158:89–93. 29. Almeida FG, Freitas DG, Bruschini H. Is the ultrasound-estimated bladder weight a reliable method for evaluating bladder outlet obstruction? BJU Int 2011; 108:864–867. 30. Morris V, Steventon N, Hazbun S, Wagg A. A cross-sectional study of ultrasound estimated bladder weight in a sample of men and women without lower urinary tract symptoms. Neurourol Urodyn 2009; 28:995–997. 31. Han DH, Lee HW, Sung HH, et al. The diagnostic efficacy of 3-dimensional ultrasound estimated bladder weight corrected for body surface area as an alternative nonurodynamic parameter of bladder outlet obstruction. J Urol 2011; 185:964–969. 32. MacNab AJ, Stothers L. Near-infrared spectroscopy: validation of bladderoutlet obstruction assessment using noninvasive parameters. Can J Urol 2008; 15:4241–4248. 33. Stothers L, Guevara R, MacNab A. Classification of male lower urinary tract symptoms using mathematical modelling and a regression tree algorithm of noninvasive near-infrared spectroscopy parameters. Eur Urol 2010; 57:327– 332. 34. Yurt M, Suer E, Gulpinar O, et al. Diagnosis of bladder outlet obstruction in & men with lower urinary tract symptoms: comparison of near infrared spectroscopy algorithm and pressure flow study in a prospective study. Urology 2012; 80:182–186. This is a prospective study showing the sensitivity and specificity of NIRS compared with cystometry. 35. Macnab AJ, Shadgan B, Stothers L, Afshar K. Ambulant monitoring of bladder & oxygenation and hemodynamics using wireless near-infrared spectroscopy. Can Urol Assoc J 2013; 7:E98–E104. This study shows that wireless NIRS is possible opening the investigation up to ambulatory testing. 36. Macnab AJ, Stothers LS, Shadgan B. Monitoring detrusor oxygenation and hemodynamics noninvasively during dysfunctional voiding. Adv Urol 2012; 2012:; 676303. 37. Chung DE, Lee RK, Kaplan SA, Te AE. Concordance of near infrared spectroscopy with pressure flow studies in men with lower urinary tract symptoms. J Urol 2010; 184:2434–2439. 38. Vijaya G, Digesu GA, Derpapas A, et al. Changes in detrusor muscle oxygenation during detrusor overactivity contractions. Eur J Obstet Gynecol Reprod Biol 2012; 163:104–107. 39. Mastoroudes H, Giarenis I, Vella M, et al. Use of near infrared spectroscopy as an alternative to videourodynamics to detect detrusor overactivity in women with the overactive bladder syndrome. Urology 2012; 80:547–550. 40. Pel JJ, van Mastrigt R. Noninvasive measurement of bladder pressure using an external catheter. Neurourol Urodyn 1999; 18:455–469. 41. Pel JJ, Bosch JL, Blom JH, et al. Development of a noninvasive strategy to classify bladder outlet obstruction in male patients with LUTS. Neurourol Urodyn 2002; 21:117–125. 42. van MR, Huang Foen Chung JW. Bladder volume sensitivity of isovolumetric intravesical pressure. Neurourol Urodyn 2006; 25:744–751.
0963-0643 ß 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins
www.co-urology.com
19
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Benign prostatic hyperplasia 43. Mastrigt R, Huang Foen Chung JW. Comparison of repeatability of noninvasive and invasive urodynamics. Neurourol Urodyn 2004; 23:317–321. 44. Huang Foen Chung JW, Bohnen AM, Pel JJ, et al. Applicability and reproducibility of condom catheter method for measuring isovolumetric bladder pressure. Urology 2004; 63:56–60. 45. Gleason DM, Bottaccini MR, McRae LP. Noninvasive urodynamics: a study of male voiding dysfunction. Neurourol Urodyn 1997; 16:93–100. 46. Griffiths CJ, Rix D, MacDonald AM, et al. Noninvasive measurement of bladder pressure by controlled inflation of a penile cuff. J Urol 2002; 167:1344– 1347. 47. McIntosh SL, Drinnan MJ, Griffiths CJ, et al. Noninvasive assessment of bladder contractility in men. J Urol 2004; 172:1394–1398. 48. Drinnan MJ, McIntosh SL, Robson WA, et al. Inter-observer agreement in the estimation of bladder pressure using a penile cuff. Neurourol Urodyn 2003; 22:296–300. 49. Harding CK, Robson W, Drinnan MJ, et al. Variation in invasive and noninvasive measurements of isovolumetric bladder pressure and categorization of obstruction according to bladder volume. J Urol 2006; 176:172–176. 50. Borrini L, Lukacs B, Ciofu C, et al. Predictive value of the penile cuff-test for the & assessment of bladder outlet obstruction in men. Prog Urol 2012; 22:657– 664. This study shows good patient tolerance of the penile cuff test which produced a negative predictive value of 88% and positive predictive value of 82% compared with cystometry. 51. Harding C, Robson W, Drinnan M, et al. Predicting the outcome of prostatectomy using noninvasive bladder pressure and urine flow measurements. Eur Urol 2007; 52:186–192.
20
www.co-urology.com
52. Clarkson B, Griffiths C, McArdle F, et al. Continuous noninvasive measurement of bladder voiding pressure using an experimental constant low-flow test. Neurourol Urodyn 2012; 31:557–563. 53. Zinner NR, Ritter RC, Sterling AM, Harding DC. Drop spectrometer: a nonobstructive, noninterfering instrument for analyzing hydrodynamic properties of human urination. J Urol 1969; 101:914–918. 54. Wheeler AP, Morad S, Buchholz N, Knight MM. The shape of the urine & stream–from biophysics to diagnostics. PLoS One 2012; 7:; e47133.. This is a good review of the biophysics of voiding and the test used to calculate these parameters. 55. Ding YY, Ozawa H, Yokoyama T, et al. Reliability of color Doppler ultrasound urodynamics in the evaluation of bladder outlet obstruction. Urology 2000; 56:967–971. 56. Ozawa H, Chancellor MB, Ding YY, et al. Noninvasive urodynamic evaluation of bladder outlet obstruction using Doppler ultrasonography. Urology 2000; 56:408–412. 57. Inui E, Ochiai A, Naya Y, et al. Comparative morphometric study of bladder detrusor between patients with benign prostatic hyperplasia and controls. J Urol 1999; 161:827–830. 58. Mirone V, Imbimbo C, Sessa G, et al. Correlation between detrusor collagen content and urinary symptoms in patients with prostatic obstruction. J Urol 2004; 172:1386–1389. 59. Elbadawi A, Yalla SV, Resnick NM. Structural basis of geriatric voiding dysfunction. IV. Bladder outlet obstruction. J Urol 1993; 150:1681–1695. 60. Nepomnyashchikh LM, Lushnikova EL, Neimark AI. Remodeling of the muscle layer (detrusor muscle) of hyperactive bladder disease in patients with benign prostatic hyperplasia. Bull Exp Biol Med 2012; 153:778–783.
Volume 24 Number 1 January 2014
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Modern evaluation of lower urinary tract symptoms in 2014 Altaf Mangera and Christopher Chapple
Purpose of review To evaluate and present the evidence for the use of different investigation modalities in men with benign prostatic hyperplasia/lower urinary tract symptoms (LUTS) in 2014. Recent findings Cystometry remains the gold standard in differentiating obstructed from nonobstructed men with LUTS. Prostatic ultrasound measures such as the intravesical prostatic protrusion may be useful in counselling men before a trail without catheter or commencing a antagonists. Using a higher cut-off, the bladder thickness/ weight measurement has a higher sensitivity but lower specificity and may allow men with obstruction to be excluded from requiring cystometry. These and other techniques such as near-infrared spectroscopy, penile cuff compression and computational flow modelling have shown good correlation with cystometry but still require more data, technical refinement and standardization, before they can be considered to be appropriate in routine clinical practice. Summary The last few years have seen an increase in the data regarding less invasive methods of cystometry. Although these do not provide the same information as cystometry, they may have a role in answering specific questions and counselling men with benign prostatic hyperplasia/LUTS. The key to incorporating these techniques in the assessment of men will lie with standardization and use for specific indications. Keywords bladder outflow obstruction, computational flow modelling, cystometry, infrared spectroscopy, intravesical prostatic protrusion, penile cuff compression, resistive index, urodynamics
INTRODUCTION
PROSTATE IMAGING
It is without doubt that uroflowmetry is useful in the assessment of men with lower urinary tract voiding symptoms (LUTS). However, a simple flow rate lacks the ability to differentiate obstructed (high pressure, low flow) voiding from detrusor underactivity (low pressure low flow). This distinction is significant, as those men without obstruction are less likely to be benefitted by prostatic surgery. This is where cystometry may be beneficial. This procedure is, however, invasive, costly and timeconsuming. It is probably not required in all men with an enlarged prostate, voiding symptoms and a classical flow rate pattern. However, its use in equivocal cases, mixed symptoms, failed surgery and chronic retention is less disputed. This review will explore the new less-invasive techniques being developed as a potential alternative to conventional cystometry.
The prostate volume as measured with ultrasound has been shown to correlate poorly with symptoms of bladder outflow obstruction (BOO). The transitional zone size, which is predominantly affected by benign enlargement, has also not shown good correlation with urodynamic findings [1]. The resistive index in the prostatic arteries may be measured via colour Doppler. The theory behind this measure is that the larger transitional zone compresses the prostatic arteries against the capsule Sheffield Teaching Hospitals, Glossop Road, Sheffield, UK Correspondence to Christopher Chapple, MD, Consultant Urological Surgeon, Sheffield Teaching Hospitals, Glossop Road, Sheffield S10 2 JF, UK. Tel: +44 114 271 2559; fax: +44 114 279 7841; e-mail: [email protected] Curr Opin Urol 2014, 24:15–20 DOI:10.1097/MOU.0000000000000013
0963-0643 ß 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins
www.co-urology.com
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Benign prostatic hyperplasia
KEY POINTS Pressure flow cystometry remains the gold standard investigation modality for men with benign prostatic hyperplasia (BPH)/LUTS. The use of prostate ultrasound measures may be useful in deciding whether medical therapy may be beneficial. Detrusor thickness and weight assessment still requires better standardization and needs to be assessed in different populations. NIRS has a high specificity for obstruction but requires expertise in assessment and interpretation. The penile cuff test may be useful in deciding which men are obstructed and suitable for surgery but is less useful in excluding unobstructed men who may then need to progress to formal urodynamics.
thus reducing flow. The resistive index is calculated transrectally based on the peak systolic velocity – end diastolic velocity/peak systolic velocity. The resistive index has been reported to have a sensitivity of 78% and specificity of 86% for diagnosing BOO [2 ]. One study in 572 men showed the area under the receiveroperating characteristic (ROC) curve to be 0.87, which was higher than the transitional zone index and total prostate volume in predicting an effective outcome after transurethral resection of prostate (TURP) [3]. Another study in 239 men showed an area under the curve (AUC) of 0.816, which was better than that for bladder wall thickness (BWT) and ultrasound-estimated bladder weight [4 ]. The resistive index is affected by diabetes, arteriosclerosis and medications and can be operator-dependent. These limitations still need further investigation. Intravesical prostatic protrusion has also been investigated [5]. If the length of prostate protrusion from its base is greater than 10 mm, then it has been shown that a blockers may be ineffective [6 ,7 ], and surgery is likely to be more effective [8]. A recent study has reported an AUC of 0.71 for predicting BOO symptoms [9 ]. Another study reported an AUC compared with the BOO index of 0.84 [10]. Also, there is a higher likelihood of trail without catheter (TWOC) failure in men with acute urinary retention if the intravesical prostatic protrusion (IPP) is greater than 10 mm [11]. The prostatic urethral angle occurs between the membranous and prostatic urethra. When correlated with the bladder outflow obstruction index (BOOI), the area under the ROC curve was 0.63 in one study [12]. An angle of greater than 35 degrees was shown to correlate with BOO, but an increasing angle did not correlate with the degree of BOO. &
&&
&
&
16
www.co-urology.com
&
The limitations of the above studies are that they arise from the notion of prostatic obstruction and cannot inform upon bladder contractility. If detrusor compensation or decompensation has occurred secondary to prostatic obstruction, or in cases of detrusor underactivity, these studies will in theory not be useful in deciding who is likely to benefit from outflow obstruction surgery. Also, the conditions for the above measures are not fully standardized and parameters such as comorbidity and bladder volume during assessment need to be defined. However, their utility may be in deciding which men are at risk for progression and may benefit from early treatment.
BLADDER THICKNESS/WEIGHT BWT and detrusor wall thickness (DWT) may be measured via ultrasound. BWT has been suggested to correlate less with BOO than DWT, as the mucosal layer of the bladder may be affected by other pathologies and it is the detrusor that is most affected by BOO [13]. This may explain why there is some discrepancy in the reports correlating BWT with pressure flow studies. Manieri et al. [14] showed a significant correlation (r > 0.6) with a cut-off of 5 mm, with 63% of men with a thickness less than this being unobstructed and 88% above this being obstructed. However, Hakenberg et al. [15] showed that BWT increases slightly with age and the cut-off for men with BPE was only 0.3 mm greater than men without symptoms. Another parameter shown to affect BWT is BMI [16 ]. Blatt et al. [17] also found no correlation in BWT with urodynamic studies in non-neurogenic patients with a multitude of symptoms. Women with detrusor overactivity have been shown to have a higher BWT compared with those without detrusor overactivity, as it has been suggested that detrusor overactivity against a closed urethra may lead to detrusor hypertrophy [18]. Another study reported a significant reduction in BWT after the use of tamsulosin for 2 months, although the actual reduction was small at 0.77 mm [19]. Oelke et al. have prospectively compared anterior DWT more than 2 mm with a 7.5-MHz ultrasound at functional bladder capacity to standard urodynamics. The technique had a sensitivity of 83%, specificity of 95%, positive and negative predictive values of 94% and 86%, respectively [20]. The AUC for DWT was found to be 0.723 for successful TURP in 239 men [4 ]. DWT decreases continuously with increasing bladder filling up to only 250 ml, but thereafter remains stable until maximum bladder capacity. Interobserver variability has been reported at 4–12.3% [21], but the majority &&
&&
Volume 24 Number 1 January 2014
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Modern evaluation of LUTS in 2014 Mangera and Chapple
may be the result of technical variations such as bladder filling volume, region of measurement and frequency of ultrasound probe [22]. Other problems with this technique are that minimal changes need to be interpreted that is less than 2 mm. Kessler et al. have reported a 100% sensitivity and positive predictive value with a higher cut-off of more than 2.9 mm, but this led to a lower specificity of 43% and negative predictive value of 54% in a study of 102 men [21]. Using a higher cut-off may at least allow the inclusion of men most likely to benefit from surgery, whereby those excluded may then progress to cystometry. The ultrasound estimated bladder weight (UEBW) is a technique that is proposed to overcome the influence of bladder-filling volume [23]. This is calculated from the thickness of the bladder wall and the intravesical volume, assuming a spherical bladder. The UEBW was shown in one study to correlate poorly with Qmax [24] but correlated well with bladder weight excised at autopsy [23]. The AUC for UEBW for patients who had a successful TURP was found to be 0.723 [4 ]. The cut-off proposed to correlate with pressure flow studies is 35 g [25–27]. Kojima et al. [25] showed in 65 men that this had a diagnostic accuracy of 86% for BOO. Another study showed that men were 13 times more likely to develop acute urinary retention if above this cut-off and had an area under the ROC curve of 0.8 [26]. Interestingly, post prostatectomy, the UEBW has been shown to reduce from 53 to 32 g [28]. It must be noted that all these studies are in Japanese men and therefore may not be transferrable to other populations. In South American and European men, a correlation between UEBW and BOO has not been found [24,29]. In healthy volunteers, the UEBW has been shown to be influenced by height and body surface area [30]. Therefore Han et al. [31] have shown that the diagnostic accuracy of UEBW may be enhanced by correction for body surface area with a sensitivity of 62% and specificity of 83%.
with a specificity of 88% for NIRS compared with pressure flow studies [33]. Similarly, another study, by a different group, has reported a sensitivity of 86.2% and specificity of 87.5% [34 ]. More recently, a wireless NIRS monitor has been shown to lead to comparable results [35 ]. Problems with NIRS are that motion artefact and abdominal straining may affect readings, obesity may make readings difficult, there is still considerable intra-patient variability and there are technical failures [32,36]. In addition, patients with chronic health conditions (vascular disease, renal failure and so on) have been excluded from one study [34 ] and the study by Stothers et al. [33] did not include any diabetes patients. One study in the literature showed poor correlation between urodynamics and NIRS with an AUC of 0.48 [37]. However, the algorithm utilized in this study has subsequently been improved [33]. It was suggested that NIRS may be useful also in assessing detrusor overactivity [38]; however, a recent study has shown poor sensitivity and specificity for this [39]. &
&
&
&&
NEAR-INFRARED SPECTROSCOPY This technique measures concentration of oxyhaemoglobin and deoxyhaemoglobin levels in tissue. Increased work by the detrusor muscle (as occurs in BOO) leads to a reduction in oxyhaemoglobin levels (downward slope), whereas in an unobstructed system, oxyhaemoglobin levels increase (upward slope). When applying a customized algorithm utilizing the Qmax, post void residual and NIRS, MacNab et al. [32] were able to correctly identify 86% of men as obstructed or unobstructed. Another study reported misclassification of BOO in only 4%
CONDOM CATHETER METHOD A sheath modified with a pressure transducer, which measures the isovolumetric pressure (Pves.iso), is worn over the penis. The Pves.iso is the pressure generated by the contracting bladder against a closed bladder outlet. The patient is asked to initiate voiding and the flow out of the condom is interrupted several times. This therefore allows the determination of maximum intravesical pressure. The urethral resistance may be calculated from the maximum condom pressure and the Qmax. The recorded pressures are significantly higher in nonobstructed patients [40,41]. Pressures should ideally be recorded with bladder volumes above 247 ml, as below this they are less accurate [42]. In addition, the flow rate needs to be more than 5.4 ml/s to allow adequate flow for interruption. Other problems include failed measurement because of leaking and urethral closure because of straining. Repeatability similar to pressure flow studies has been shown with a success rate of 94% [43,44]. Correct categorization of men into obstructed and nonobstructed categories was found in 42 of 46 patients with reference to urodynamics [41].
PENILE CUFF TEST A pneumatic cuff is placed around the penis and with cuff inflation the flow is interrupted. The pressure of the fluid column in the urethra is equated to the intravesical pressure assuming a continuous fluid column connecting both points. Two methods of measurement have been described. The deflation
0963-0643 ß 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins
www.co-urology.com
17
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Benign prostatic hyperplasia
techniques involve inflation of the cuff, followed by permission to void against a closed cuff and the cuff is released when the patient feels urine in the urethra [45]. With the interruption technique, voiding is halted mid flow and then the cuff is deflated rapidly resulting in a surge of urine (Qsurge), followed by steady state flow (Qss) [46]. This cycle may be repeated multiple times. The penile compression release index is calculated as (Qsurg Qss)/Qss. The estimation of intravesical pressure has been shown to be 15 cmH2O higher than standard cystometry, which has been put down to the cuff being placed below bladder height [47]. In addition, good reproducibility and interobserver agreement has been shown on repeat testing especially if voided volumes are more than 150 ml [47,48]. The maximum value of cuff interruption pressure plotted on a noninvasive pressure flow nomogram has been proposed to provide the best diagnostic accuracy [49]. A positive predictive value of 82% and a negative predictive value of 88% have been reported [50 ]. More interestingly, men deemed to be obstructed by the penile cuff test had an 87% chance of a good outcome after TURP compared with only 56% who were deemed obstructed [51]. This differentiation may be useful in excluding men who are obstructed and therefore do not need invasive urodynamics. There are a few limitations, such as a high trace exclusion rate due to technical problems, abdominal straining is unaccounted for and there is a high equivocal outcome rate in which patients have a success of 78% following TURP [51]. More recently, a continuous penile compression technique has been described that slows the flow down to 2.5 ml/s [52]. The authors have reported good agreement between cuff and intravesical pressures throughout the void. Although promising, there are no correlations with pressure flow studies to date. &
COMPUTATIONAL MODELLING OF FLOW The shape or wave pattern made by the urine stream exiting the urethral meatus may contain diagnostic information regarding voiding. The liquid jet exiting a noncylindrical aperture deforms under surface tension forces. High-speed cinematography may demonstrate the urine stream break into drops on exiting the urethral meatus. In the drop spectrometer, the stream is passed through a horizontal beam, which is deflected by each drop and the light is detected by a photodetector [53]. It is proposed that the shape and speed of the drops in the stream may give an indication of detrusor pressure. However, the limitation with this thus far has been the correction required for individuals’ urethral geometry [54 ]. &
18
www.co-urology.com
Doppler ultrasound may be used to assess flow through the prostatic urethra. Flow velocity curves can be created at the distal prostatic urethra and at the membranous urethra with reasonable inter-rater reliability [55]. In men with BOO, the ratio of the Qmax/maximum velocity is lower. The ratio of the maximum velocities at the two sites correlates with obstruction with a Spearman’s rho of 0.7 [56]. A velocity ratio more than 1.6 correctly classified 22 men as obstructed according to pressure flow criteria. The limitations of this procedure are cost, specialization is required to take the recordings and the measurements are performed seated (most men void standing).
HISTOLOGICAL ASSESSMENT OF DETRUSOR FUNCTION It has been shown that detrusor hypertrophy may occur secondary to BPO. This has been correlated to histological findings, which showed increased connective tissue relative to smooth muscle [57,58]. Elbadawi et al. [59] have shown that those with urodynamically proven obstruction had myohypertrophy with wide spaces between muscle cells. Conversely, those who were unobstructed showed degeneration of muscle cells and axons. More recently, it has been shown that parts of the detrusor muscle degenerate and are eliminated. Thereafter, compensatory hypertrophy of the remaining cells with replacement fibrosis occurs [60]. It has been suggested that knowing the histological make-up of detrusor muscle may be able to predict detrusor underactivity; however, correlative studies are still required to show this.
CONCLUSION Despite advances in technology and research, pressure flow studies still remain the gold standard in differentiating obstructed from nonobstructed men. There may be some utility in using IPP to decide whether men will benefit from a blockers and should undergo surgery earlier. The other techniques still require refinement and evaluation in wider populations with better standardization. Acknowledgements None. Conflicts of interest C.C. is a Speaker for Ranbaxy, Consultant for AMS, Lilly and ONO, and Consultant, Researcher, Speaker and Trial Participation for Allergan, Astellas, Pfizer and Recordati. Volume 24 Number 1 January 2014
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Modern evaluation of LUTS in 2014 Mangera and Chapple
REFERENCES AND RECOMMENDED READING Papers of particular interest, published within the annual period of review, have been highlighted as: & of special interest && of outstanding interest
1. Witjes WP, Aarnink RG, Ezz-el-Din K, et al. The correlation between prostate volume, transition zone volume, transition zone index and clinical and urodynamic investigations in patients with lower urinary tract symptoms. Br J Urol 1997; 80:84–90. 2. Zhang X, Li G, Wei X, et al. Resistive index of prostate capsular arteries: & a newly identified parameter to diagnose and assess bladder outlet obstruction in patients with benign prostatic hyperplasia. J Urol 2012; 188:881– 887. This study shows that resistive index has a sensitivity of 78% and specificity of 86% in men with BOO. 3. Shinbo H, Kurita Y, Nakanishi T, et al. Resistive index: a newly identified predictor of outcome of transurethral prostatectomy in patients with benign prostatic hyperplasia. Urology 2010; 75:143–147. 4. Huang T, Qi J, Yu YJ, et al. Predictive value of resistive index, detrusor wall && thickness and ultrasound estimated bladder weight regarding the outcome after transurethral prostatectomy for patients with lower urinary tract symptoms suggestive of benign prostatic obstruction. Int J Urol 2012; 19:343– 350. This study investigated IPP, resistive index, DWT and UEBW via ultraosund in 239 patients. When compared with success after TURP ,the resistive index, DWT and UEBW showed good correlation with the resistive index having the greatest AUC. This is the only study to date to compare a range of techniques and therefore could also assess the combination of these techniques, which improved the positive predictive value to 96%. 5. Lieber MM, Jacobson DJ, McGree ME, et al. Intravesical prostatic protrusion in men in Olmsted County, Minnesota. J Urol 2009; 182:2819–2824. 6. Cumpanas AA, Botoca M, Minciu R, Bucuras V. Intravesical prostatic protru& sion can be a predicting factor for the treatment outcome in patients with lower urinary tract symptoms due to benign prostatic obstruction treated with tamsulosin. Urology 2013; 81:859–863. This study questions the use of a blockers in men with IPP greater than 10 mm. This is useful when deciding which men should receive a TWOC and who should proceed to surgery. 7. Seo YM, Kim HJ. Impact of intravesical protrusion of the prostate in the & treatment of lower urinary tract symptoms/benign prostatic hyperplasia of moderate size by alpha receptor antagonist. Int Neurourol J 2012; 16:187– 190. Similar to above study, IPP may be used to define which men may benefit from a blockers. 8. Lee JW, Ryu JH, Yoo TK, et al. Relationship between intravesical prostatic protrusion and postoperative outcomes in patients with benign prostatic hyperplasia. Korean J Urol 2012; 53:478–482. 9. Aganovic D, Hasanbegovic M, Prcic A, et al. Which is a better indicator of & bladder outlet obstruction in patients with benign prostatic enlargement– intravesical protrusion of prostate or bladder wall thickness? Med Arh 2012; 66:324–328. Thus study shows that IPP correlates better with BOOI than BWT. 10. Franco G, De NC, Leonardo C, et al. Ultrasound assessment of intravesical prostatic protrusion and detrusor wall thickness–new standards for noninvasive bladder outlet obstruction diagnosis? J Urol 2010; 183:2270– 2274. 11. Syazarina SO, Zulkifli MZ, Hamzaini AH. Predicting outcome of trial of voiding without catheter in acute urinary retention with intravesical prostatic protrusion. Malays J Med Sci 2013; 20:56–59. 12. Ku JH, Ko DW, Cho JY, Oh SJ. Correlation between prostatic urethral angle and bladder outlet obstruction index in patients with lower urinary tract symptoms. Urology 2010; 75:1467–1471. 13. Bright E, Oelke M, Tubaro A, Abrams P. Ultrasound estimated bladder weight and measurement of bladder wall thickness–useful noninvasive methods for assessing the lower urinary tract? J Urol 2010; 184:1847– 1854. 14. Manieri C, Carter SS, Romano G, et al. The diagnosis of bladder outlet obstruction in men by ultrasound measurement of bladder wall thickness. J Urol 1998; 159:761–765. 15. Hakenberg OW, Linne C, Manseck A, Wirth MP. Bladder wall thickness in normal adults and men with mild lower urinary tract symptoms and benign prostatic enlargement. Neurourol Urodyn 2000; 19:585–593. 16. Bright E, Pearcy R, Abrams P. Automatic evaluation of ultrasonography&& estimated bladder weight and bladder wall thickness in community-dwelling men with presumably normal bladder function. BJU Int 2012; 109:1044– 1049. This study revealed that the bladder weight correlated with patient weight, BMI and filling volume more than IPSS socres in 100 male volunteers. 17. Blatt AH, Titus J, Chan L. Ultrasound measurement of bladder wall thickness in the assessment of voiding dysfunction. J Urol 2008; 179:2275–2278.
18. Khullar V, Cardozo LD, Salvatore S, Hill S. Ultrasound: a noninvasive screening test for detrusor instability. Br J Obstet Gynaecol 1996; 103:904– 908. 19. Eghbali K, Shayegan MR, Kianoush S. Investigating the effect of tamsulosin on the measurement of bladder wall thickness and International Prostate Symptom Score in benign prostatic hyperplasia. Can Urol Assoc J 2013; 7:E317–E321. 20. Oelke M, Hofner K, Jonas U, et al. Diagnostic accuracy of noninvasive tests to evaluate bladder outlet obstruction in men: detrusor wall thickness, uroflowmetry, postvoid residual urine, and prostate volume. Eur Urol 2007; 52:827– 834. 21. Kessler TM, Gerber R, Burkhard FC, et al. Ultrasound assessment of detrusor thickness in men-can it predict bladder outlet obstruction and replace pressure flow study? J Urol 2006; 175:2170–2173. 22. Oelke M. International Consultation on Incontinence-Research Society (ICI-RS) report on noninvasive urodynamics: the need of standardization of ultrasound bladder and detrusor wall thickness measurements to quantify bladder wall hypertrophy. Neurourol Urodyn 2010; 29:634–639. 23. Kojima M, Inui E, Ochiai A, et al. Ultrasonic estimation of bladder weight as a measure of bladder hypertrophy in men with infravesical obstruction: a preliminary report. Urology 1996; 47:942–947. 24. Bright E, Pearcy R, Abrams P. Ultrasound estimated bladder weight in men attending the uroflowmetry clinic. Neurourol Urodyn 2011; 30:583– 586. 25. Kojima M, Inui E, Ochiai A, et al. Noninvasive quantitative estimation of infravesical obstruction using ultrasonic measurement of bladder weight. J Urol 1997; 157:476–479. 26. Miyashita H, Kojima M, Miki T. Ultrasonic measurement of bladder weight as a possible predictor of acute urinary retention in men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia. Ultrasound Med Biol 2002; 28:985–990. 27. Akino H, Maekawa M, Nakai M, et al. Ultrasound-estimated bladder weight predicts risk of surgery for benign prostatic hyperplasia in men using alphaadrenoceptor blocker for LUTS. Urology 2008; 72:817–820. 28. Kojima M, Inui E, Ochiai A, et al. Reversible change of bladder hypertrophy due to benign prostatic hyperplasia after surgical relief of obstruction. J Urol 1997; 158:89–93. 29. Almeida FG, Freitas DG, Bruschini H. Is the ultrasound-estimated bladder weight a reliable method for evaluating bladder outlet obstruction? BJU Int 2011; 108:864–867. 30. Morris V, Steventon N, Hazbun S, Wagg A. A cross-sectional study of ultrasound estimated bladder weight in a sample of men and women without lower urinary tract symptoms. Neurourol Urodyn 2009; 28:995–997. 31. Han DH, Lee HW, Sung HH, et al. The diagnostic efficacy of 3-dimensional ultrasound estimated bladder weight corrected for body surface area as an alternative nonurodynamic parameter of bladder outlet obstruction. J Urol 2011; 185:964–969. 32. MacNab AJ, Stothers L. Near-infrared spectroscopy: validation of bladderoutlet obstruction assessment using noninvasive parameters. Can J Urol 2008; 15:4241–4248. 33. Stothers L, Guevara R, MacNab A. Classification of male lower urinary tract symptoms using mathematical modelling and a regression tree algorithm of noninvasive near-infrared spectroscopy parameters. Eur Urol 2010; 57:327– 332. 34. Yurt M, Suer E, Gulpinar O, et al. Diagnosis of bladder outlet obstruction in & men with lower urinary tract symptoms: comparison of near infrared spectroscopy algorithm and pressure flow study in a prospective study. Urology 2012; 80:182–186. This is a prospective study showing the sensitivity and specificity of NIRS compared with cystometry. 35. Macnab AJ, Shadgan B, Stothers L, Afshar K. Ambulant monitoring of bladder & oxygenation and hemodynamics using wireless near-infrared spectroscopy. Can Urol Assoc J 2013; 7:E98–E104. This study shows that wireless NIRS is possible opening the investigation up to ambulatory testing. 36. Macnab AJ, Stothers LS, Shadgan B. Monitoring detrusor oxygenation and hemodynamics noninvasively during dysfunctional voiding. Adv Urol 2012; 2012:; 676303. 37. Chung DE, Lee RK, Kaplan SA, Te AE. Concordance of near infrared spectroscopy with pressure flow studies in men with lower urinary tract symptoms. J Urol 2010; 184:2434–2439. 38. Vijaya G, Digesu GA, Derpapas A, et al. Changes in detrusor muscle oxygenation during detrusor overactivity contractions. Eur J Obstet Gynecol Reprod Biol 2012; 163:104–107. 39. Mastoroudes H, Giarenis I, Vella M, et al. Use of near infrared spectroscopy as an alternative to videourodynamics to detect detrusor overactivity in women with the overactive bladder syndrome. Urology 2012; 80:547–550. 40. Pel JJ, van Mastrigt R. Noninvasive measurement of bladder pressure using an external catheter. Neurourol Urodyn 1999; 18:455–469. 41. Pel JJ, Bosch JL, Blom JH, et al. Development of a noninvasive strategy to classify bladder outlet obstruction in male patients with LUTS. Neurourol Urodyn 2002; 21:117–125. 42. van MR, Huang Foen Chung JW. Bladder volume sensitivity of isovolumetric intravesical pressure. Neurourol Urodyn 2006; 25:744–751.
0963-0643 ß 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins
www.co-urology.com
19
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Benign prostatic hyperplasia 43. Mastrigt R, Huang Foen Chung JW. Comparison of repeatability of noninvasive and invasive urodynamics. Neurourol Urodyn 2004; 23:317–321. 44. Huang Foen Chung JW, Bohnen AM, Pel JJ, et al. Applicability and reproducibility of condom catheter method for measuring isovolumetric bladder pressure. Urology 2004; 63:56–60. 45. Gleason DM, Bottaccini MR, McRae LP. Noninvasive urodynamics: a study of male voiding dysfunction. Neurourol Urodyn 1997; 16:93–100. 46. Griffiths CJ, Rix D, MacDonald AM, et al. Noninvasive measurement of bladder pressure by controlled inflation of a penile cuff. J Urol 2002; 167:1344– 1347. 47. McIntosh SL, Drinnan MJ, Griffiths CJ, et al. Noninvasive assessment of bladder contractility in men. J Urol 2004; 172:1394–1398. 48. Drinnan MJ, McIntosh SL, Robson WA, et al. Inter-observer agreement in the estimation of bladder pressure using a penile cuff. Neurourol Urodyn 2003; 22:296–300. 49. Harding CK, Robson W, Drinnan MJ, et al. Variation in invasive and noninvasive measurements of isovolumetric bladder pressure and categorization of obstruction according to bladder volume. J Urol 2006; 176:172–176. 50. Borrini L, Lukacs B, Ciofu C, et al. Predictive value of the penile cuff-test for the & assessment of bladder outlet obstruction in men. Prog Urol 2012; 22:657– 664. This study shows good patient tolerance of the penile cuff test which produced a negative predictive value of 88% and positive predictive value of 82% compared with cystometry. 51. Harding C, Robson W, Drinnan M, et al. Predicting the outcome of prostatectomy using noninvasive bladder pressure and urine flow measurements. Eur Urol 2007; 52:186–192.
20
www.co-urology.com
52. Clarkson B, Griffiths C, McArdle F, et al. Continuous noninvasive measurement of bladder voiding pressure using an experimental constant low-flow test. Neurourol Urodyn 2012; 31:557–563. 53. Zinner NR, Ritter RC, Sterling AM, Harding DC. Drop spectrometer: a nonobstructive, noninterfering instrument for analyzing hydrodynamic properties of human urination. J Urol 1969; 101:914–918. 54. Wheeler AP, Morad S, Buchholz N, Knight MM. The shape of the urine & stream–from biophysics to diagnostics. PLoS One 2012; 7:; e47133.. This is a good review of the biophysics of voiding and the test used to calculate these parameters. 55. Ding YY, Ozawa H, Yokoyama T, et al. Reliability of color Doppler ultrasound urodynamics in the evaluation of bladder outlet obstruction. Urology 2000; 56:967–971. 56. Ozawa H, Chancellor MB, Ding YY, et al. Noninvasive urodynamic evaluation of bladder outlet obstruction using Doppler ultrasonography. Urology 2000; 56:408–412. 57. Inui E, Ochiai A, Naya Y, et al. Comparative morphometric study of bladder detrusor between patients with benign prostatic hyperplasia and controls. J Urol 1999; 161:827–830. 58. Mirone V, Imbimbo C, Sessa G, et al. Correlation between detrusor collagen content and urinary symptoms in patients with prostatic obstruction. J Urol 2004; 172:1386–1389. 59. Elbadawi A, Yalla SV, Resnick NM. Structural basis of geriatric voiding dysfunction. IV. Bladder outlet obstruction. J Urol 1993; 150:1681–1695. 60. Nepomnyashchikh LM, Lushnikova EL, Neimark AI. Remodeling of the muscle layer (detrusor muscle) of hyperactive bladder disease in patients with benign prostatic hyperplasia. Bull Exp Biol Med 2012; 153:778–783.
Volume 24 Number 1 January 2014
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
