Predicting the outcome of prostatectomy using noninvasive bladder pressure and urine flow measurements.

OBJECTIVES: To determine whether categorisation of bladder outlet obstruction (BOO) using measurements of bladder pressure and urine flow obtained by a novel noninvasive medical device (the penile cuff test) improves prediction of outcome from endoscopic prostatectomy (TURP). METHODS: A consecutive cohort of 208 men undergoing TURP following standard assessment in our institution was recruited, and 179 (86%) completed the protocol. Each subject underwent a penile cuff test prior to surgery; outcome was assessed by change in IPSS at 4 mo. The proportion of men with good outcome (>50% reduction in IPSS) was compared according to categorisation by noninvasive bladder pressure and urine flow measurements. RESULTS: The cuff test was completed by 93% of men with 2% experiencing an adverse event. Men categorised as having BOO by the test (37% of total) had an 87% chance of a good outcome from TURP (p<0.01), whilst of those deemed not obstructed (19% of total) 56% experienced good outcome (p<0.01). For the remaining men not categorised in these two groups, 77% had good outcome, which was identical to the result of the cohort as a whole (77%, p=NS). CONCLUSIONS: Urodynamic categorisation using measurements obtained by the noninvasive penile cuff test improves prediction of outcome for men with LUTS undergoing TURP. This finding together with the ease and acceptability of the test suggest its suitability for office-based clinical use to assist men and their physicians in the selection for surgical treatment for relief of LUTS.

Penile fracture.

BACKGROUND: A 23-year-old man presented with a painful penis following sexual intercourse. On examination he had a swollen, bruised penis that was tender on palpation, most markedly on the right lateral aspect. INVESTIGATIONS: Urinalysis. DIAGNOSIS: Rupture of right corpus cavernosum. MANAGEMENT: Immediate surgical repair.

Noninvasive assessment of bladder contractility in men.

PURPOSE: Preoperative assessment of detrusor function by pressure flow study (PFS) improves outcome from prostatectomy but is invasive and uncomfortable for the patient. We report on a large scale validation of a novel noninvasive assessment of detrusor contractility. MATERIALS AND METHODS: A flexible cuff placed around the penis was inflated automatically during voiding until flow interruption. Cuff pressure at interruption (pcuff.int) reflects isovolumetric bladder pressure (pves.isv), a measure of detrusor contractility. For comparison 151 symptomatic men performed the cuff test with simultaneous PFS monitoring. Test/retest agreement was assessed in 91 subjects who performed a cuff test without PFS on 2 occasions. RESULTS: For the 117 (77%) subjects with an acceptable cuff pressure flow trace, Bland Altman analysis showed that pcuff.int overestimated pves.isv by a mean (s.d.) of 16.4 (27.5) cm H2O, predominantly due to the cuff being positioned below the bladder. For test/retest analysis 52 (57%) of the men who were able to attend twice provided acceptable cuff data on both occasions with a mean (s.d.) difference in pcuff.int of -3.3 (32.0) cm H2O, improving to 0.0 (20.3) cm H2O in a subgroup of 39 subjects who voided more than 150 ml. On questionnaire assessment 121 (80%) subjects preferred the cuff test to PFS. CONCLUSIONS: The cuff test gives a valid and reproducible estimate of isovolumetric bladder pressure in a manner acceptable to patients, although test failure and variability of agreement require improvement. The test may be of value in the assessment of urinary symptoms and may aid in patient selection for prostatectomy.

Relationship of abdominal pressure and body mass index in men with LUTS.

AIMS: In the development of a non-invasive method for estimating isovolumetric intravesical pressure (pves,isv) we looked for a relationship between intra-abdominal pressure (pabd) and general build, expressed as body mass index (BMI) in men with lower urinary tract symptoms (LUTS). MATERIALS AND METHODS: In 100 consecutive male patients undergoing an invasive pressure flow study (PFS) the pabd was recorded continuously during filling and voiding. The magnitude at four set points was measured: before filling, after filling, during voiding and at the end of voiding. Patients' weight (kg) and height (m) were also recorded and their BMI (weight/height(2)) was calculated. RESULTS: During the fill/void cycle pabd increased during bladder filling from 37 +/- 7 cm H2O (mean +/- SD) to 38 +/- 8 cm H2O, fell during voiding to 35 +/- 9 cm H2O before increasing to 36 +/- 8 cm H2O at the end of voiding. There was a clear relationship between the individual values of pabd and BMI (correlation co-efficient = 0.52) and to a lesser extent weight (correlation co-efficient = 0.42). The relationship with BMI was clarified by separating the subjects into groups of normal, overweight and obese. CONCLUSIONS: A clear relationship between BMI and pabd was demonstrated, but because of the difficulties in quantifying it for an individual, it is impractical to apply an adjustment to non-invasive estimates of pves,isv.

Inter-observer agreement in the estimation of bladder pressure using a penile cuff.

AIMS: Objective data are useful in quantifying a patient's lower urinary tract symptoms (LUTS). We are investigating the use of an inflatable penile cuff to obstruct flow progressively during voiding, and thereby determine the pressure p(cuff,int) at which flow is interrupted. The aim of this study was to determine the agreement between experienced observers in their estimates of p(cuff,int). METHODS: We recorded 486 cuff inflation cycles during 142 voids from 42 subjects recruited from urology out-patient's and prostate assessment clinics. Each inflation cycle was assessed independently by three experienced observers, a total of 1,458 ratings. According to our standard assessment procedure, the observers (i) indicated whether the inflation should be analyzed, (ii) estimated p(cuff,int) for those inflation cycles judged suitable for analysis, and (iii) discarded measurements that were clearly inconsistent with others from the same voiding cycle. RESULTS: Overall, 689 of the 1,458 ratings (45%) were excluded, with just 4% of all ratings discarded for inconsistency. For 385 of the 486 inflation cycles (79%) there was complete agreement that the cycle should or should not be analyzed. Thereafter, for the 262 inflation cycles analyzed by two or three observers, the overall SD error in measurements of p(cuff,int) was 4.6 cm H(2)O. CONCLUSIONS: We conclude that there is good agreement between experienced observers in their interpretation of data from the cuff test. For practical purposes, there is no need for multiple observers in the clinical application of the cuff method.

Assessment of prostatic obstruction: A cuff may be enough.

AIMS: To investigate the use of an inflatable perile cuff to obstruct flow progressively during voiding in order to provide a noninvasive measure of bladder pressure. METHODS: In this study, we explain the observed relationship of flow rate with applied cuff pressure by analogy with a simple physical model. The model comprised a fixed-pressure reservoir (simulating the bladder), a collapsible tube around which a fixed pressure could be applied (simulating the prostatic urethra), connected by rigid conduit to a further collapsible tube around which pressure could be applied (simulating the penile urethra and cuff). Flow was progressively obstructed by incremental increase of pressure applied to the "penile urethra," with the experiment being repeated for a range of fixed pressures applied to the "prostatic urethra." RESULTS: The model reproduced the typical pressure/flow curves recorded during voiding by using penile cuff inflation in normal and obstructed men. CONCLUSIONS: Our data led us to hypothesise that the relationship between cuff pressure and flow rate can be used to deduce bladder pressure during voiding, prostatic opening pressure, and urethral diameter at the flow-controlling zone, three indicators of lower urinary tract function. These measurements may add to the accuracy of diagnosis and quality of care for a large number of men with lower urinary tract symptoms.