- Email: [email protected]
Value of postvoid residual urine determination in evaluation of prostatism
VALUE
OF POSTVOID
DETERMINATION
R. C. BRUSKEWITZ, P. IVERSEN,
RESIDUAL
IN EVALUATION
URINE OF PROSTATISM*
M.D.
M.D.
P. 0. MADSEN,
M.D.
From the Clinical Science Center, University of Wisconsin, and the William S. Middleton Veterans Hospital, Madison, Wisconsin
ABSTRACT - Forty-nine patients with prostatism selected for transurethral resection of the prostate underwent repetitive postvoid residual urine volume determination as part of their comprehensive evaluation. The wide variation of residual urine determinations in individual patients and the lack of correlation between residual urine and cystoscopic, urodynamic, and symptomatic parameters are discussed.
The development of prostatic enlargement secondary to benign prostatic hyperplasia and the symptom complex prostatism are a frequent accompaniment of the aging process in the male. In addition to notation of the frequency, urgency, nocturia, diminution of the urinary stream, hesitancy, and intermittency that constitute the symptom complex prostatism, evaluation of prostatism generally includes additional objective assessment of the lower urinary tract such as endoscopic examination of the posterior urethra and bladder, rectal examination, and excretory urography. Common practice dictates that the postvoid residual urine determination is a worthwhile objective measurement of the effect of prostatic impingement on the posterior urethra. We sought to test objectively the premise that postvoid residual urine determination is necessary and useful in this evaluation by conducting a prospective study of patients with prostatism.
*Study supported in part by Veterans Administration Science Fellowship Program.
602
and by NATO
Material and Methods At the William S. Middleton Veterans Hospital 49 adult males with prostatism were preoperatively screened using detailed symptom analysis (employing a symptom score system), rectal examination, postvoid residual urine determination, excretory urography, and cystoscopy. All 49 patients were selected for transurethral prostatic resection on the basis of these parameters alone. Any patient not selected for surgery was excluded from the study. All patients under age fifty or with prostatic cancer, serious neurologic disease, urethral stricture, previous pelvic surgery, or poor surgical risk were eliminated from the study as well. In addition, a temporary exclusion was made for urinary tract infection. Patients selected for surgery underwent comprehensive urodynamic evaluation including repeated postvoid residual urine determinations. Urodynamic examination and symptom analysis were repeated three months postoperatively; to date 40 patients have completed postoperative evaluation.
UROLOGY
/
DECEMBER
1332
/
VOLUME
XX, NUMBER
6
Statistical
analysis
Paired Wilcoxon rank test was used to compare residual urine volume pre- and postoperatively. The Kruska-Wallis test was used to correlate the residual urine volume to symptoms and other findings. P < 0.05 was considered significant
.
Results Determination of postvoid residual urine volume was repeated from two to five times preoperatively in each of 47 patients. Two patients had one residual urine determination each. Residual urine was measured after flowmetry; the median residual urine volume was 55 ml with a range of 0 to 900 ml. No statistical correlation was found between preoperative residual volume (median of all determinations in each patient) and the urodynamics or cystoscopic findings, or any of the symptoms of prostatism. There was no correlation between the amount of residual urine volume and a history of previous urinary tract infection. More specifically, no significant difference was demonstrated in residual urine volume between patients with normal cystometrograms and patients with uninhibited detrusor contractions (UDC) preoperatively. Likewise, residual urine volume did not correlate with total resected prostatic weight, bladder neck-verumontanum length at cystoscopy, estimated prostatic size on rectal examination, nor the urodynamic measurements of bladder opening pressure, maximum urinary flow rate, or urethral resistance (pressure/flow’). There was no correlation between the patient’s sensation of bladder emptying, estimation of the force of the urinary stream, frequency, urgency, nocturia, urge incontinence, hesitancy, intermittency, or duration of symptoms and the measured postvoid residual urine volume. There was wide variation in residual urine determinations when repeated in the same individual patient as shown in Figure 1. However, the residual urine volume did differ significantly (one-way analysis of variance, P < 0.001) between patients. Statistical analysis of the data showed the natural logarithm of the residual urine volumes to be approximately normally distributed in each patient. Three months postoperatively the median residual urine volume was reduced significantly (P < 0.005) to 10 ml with a range of 0 to 150 ml in 40 patients. Postoperatively, residual urine volume was correlated with the urethral resistance (P <
UROLOGY
/ DECEMBER1982
/ VOLUMEXX,NUMBER6
I
I
,
I
0
100
200
300
/-A0
ML FIGURE 1. Distribution of postvoid residual urine volumes in 47 patients with prostatism.
0.02) and the symptoms of intermittency (P < 0.025) but not with any other symptomatic, cystoscopic, or urodynamic parameters. No correlation was noted between preoperative residual volume and the patient’s own estimation of his postoperative outcome. Comment Information on postvoid residual urine volume and residual urine volume in normal elderly males is sparse,’ making studies of the significance of residual urine volume in prostatism difficult. Cote, Burke, and Schoenberg2 noted that patients with prostatism and normal preoperative cystometrograms tended to have greater postvoid residual urine volumes than patients with prostatism and preoperative UDC.2 Andersen, Nordling, and Walter3 found that residual urine was correlated to the symptom urge and sense of incomplete bladder emptying and found a correlation between the duration of symptoms and the residual urine volume. They further noted that elevated urethral resistance correlated with postvoid residual urine determination, but found no correlate between maximum flow and the symptoms of frequency,
603
nocturia, pain, the force of the urinary stream, or urge incontinence. Abrams and Griffiths4 and Turner-Warwick et ~1.~ believed that elevated residual urine reflected bladder dyshnction rather than obstruction. We would agree that residual urine determination probably reflects bladder dysfunction, but we were not able to correlate it with the finding of UDC, urethral resistance, maximum urine flow rate, or any preoperative symptoms. The fact that there was wide individual variation in residual urine determinations implies that a single measurement of residual urine volume following spontaneous flow in and of itself may not be reproducible, leading us to conclude that not too much emphasis should be placed on a single determination. While transurethral resection of the prostate is frequently performed to reduce residual urine, particularly in a patient presenting with a history of lower urinary tract infection, we cannot identify an association between the volume of residual urine and infection. However, the only way to establish clearly the relationship between residual urine volume and urinary tract infection would be to compare the incidence of infection in two groups of agematched males with and without elevated residual urine volume. Unfortunately no such data are available.
604
While residual urine was significantly reduced after transurethral resection of the prostate in our patients, we cannot advocate residual urine determination as a tool for assessing the degree of prostatic obstruction, nor could we find any correlation between preoperative residual urine determination and postoperative outcome. Its value in preoperative evaluation of prostatism as a predictor of postoperative outcome is questionable. Clinical Science Center Madison, Wisconsin 53792 (DR. BRUSKEWm) To Ms. Karen Scott for assistance ACKNOWLEDGMENT. in the preparation of this manuscript.
References 1. Andersen JT, Jacobsen 0, Worm-Petersen J, and Hald T: Bladder function in healthy elderly males, Stand J Urol Nephrol 12: 123 (1978). 2. Cote RJ, Burke H, and Schoenberg HW: Prediction of unusual postoperative results by urodynamic testing in benign prostatic hyperplasia, J Ural 125: 690 (1980). 3. Andersen JT, Nordling J, and Walter S: Prostatism. I. The correlations between symptoms, cystometric, and urodynamic findings, Stand I Urol Neohrol 13: 229 (1979). 4. ibrams PI$ and G&ths DJ: T& assessment of prostatic obstruction from urodynamic measurements and from residual urine, Br J Ural 51: 129 (1979). 5. Turner-Warwick R, et al: A urodynamic view of prostatic obstruction and the results of prostatectomy, ibid 45: 631 (1973).
UROLOGY
/
DECEMBER
1982
!
VOLUME
XX, NUMBER
6
OF POSTVOID
DETERMINATION
R. C. BRUSKEWITZ, P. IVERSEN,
RESIDUAL
IN EVALUATION
URINE OF PROSTATISM*
M.D.
M.D.
P. 0. MADSEN,
M.D.
From the Clinical Science Center, University of Wisconsin, and the William S. Middleton Veterans Hospital, Madison, Wisconsin
ABSTRACT - Forty-nine patients with prostatism selected for transurethral resection of the prostate underwent repetitive postvoid residual urine volume determination as part of their comprehensive evaluation. The wide variation of residual urine determinations in individual patients and the lack of correlation between residual urine and cystoscopic, urodynamic, and symptomatic parameters are discussed.
The development of prostatic enlargement secondary to benign prostatic hyperplasia and the symptom complex prostatism are a frequent accompaniment of the aging process in the male. In addition to notation of the frequency, urgency, nocturia, diminution of the urinary stream, hesitancy, and intermittency that constitute the symptom complex prostatism, evaluation of prostatism generally includes additional objective assessment of the lower urinary tract such as endoscopic examination of the posterior urethra and bladder, rectal examination, and excretory urography. Common practice dictates that the postvoid residual urine determination is a worthwhile objective measurement of the effect of prostatic impingement on the posterior urethra. We sought to test objectively the premise that postvoid residual urine determination is necessary and useful in this evaluation by conducting a prospective study of patients with prostatism.
*Study supported in part by Veterans Administration Science Fellowship Program.
602
and by NATO
Material and Methods At the William S. Middleton Veterans Hospital 49 adult males with prostatism were preoperatively screened using detailed symptom analysis (employing a symptom score system), rectal examination, postvoid residual urine determination, excretory urography, and cystoscopy. All 49 patients were selected for transurethral prostatic resection on the basis of these parameters alone. Any patient not selected for surgery was excluded from the study. All patients under age fifty or with prostatic cancer, serious neurologic disease, urethral stricture, previous pelvic surgery, or poor surgical risk were eliminated from the study as well. In addition, a temporary exclusion was made for urinary tract infection. Patients selected for surgery underwent comprehensive urodynamic evaluation including repeated postvoid residual urine determinations. Urodynamic examination and symptom analysis were repeated three months postoperatively; to date 40 patients have completed postoperative evaluation.
UROLOGY
/
DECEMBER
1332
/
VOLUME
XX, NUMBER
6
Statistical
analysis
Paired Wilcoxon rank test was used to compare residual urine volume pre- and postoperatively. The Kruska-Wallis test was used to correlate the residual urine volume to symptoms and other findings. P < 0.05 was considered significant
.
Results Determination of postvoid residual urine volume was repeated from two to five times preoperatively in each of 47 patients. Two patients had one residual urine determination each. Residual urine was measured after flowmetry; the median residual urine volume was 55 ml with a range of 0 to 900 ml. No statistical correlation was found between preoperative residual volume (median of all determinations in each patient) and the urodynamics or cystoscopic findings, or any of the symptoms of prostatism. There was no correlation between the amount of residual urine volume and a history of previous urinary tract infection. More specifically, no significant difference was demonstrated in residual urine volume between patients with normal cystometrograms and patients with uninhibited detrusor contractions (UDC) preoperatively. Likewise, residual urine volume did not correlate with total resected prostatic weight, bladder neck-verumontanum length at cystoscopy, estimated prostatic size on rectal examination, nor the urodynamic measurements of bladder opening pressure, maximum urinary flow rate, or urethral resistance (pressure/flow’). There was no correlation between the patient’s sensation of bladder emptying, estimation of the force of the urinary stream, frequency, urgency, nocturia, urge incontinence, hesitancy, intermittency, or duration of symptoms and the measured postvoid residual urine volume. There was wide variation in residual urine determinations when repeated in the same individual patient as shown in Figure 1. However, the residual urine volume did differ significantly (one-way analysis of variance, P < 0.001) between patients. Statistical analysis of the data showed the natural logarithm of the residual urine volumes to be approximately normally distributed in each patient. Three months postoperatively the median residual urine volume was reduced significantly (P < 0.005) to 10 ml with a range of 0 to 150 ml in 40 patients. Postoperatively, residual urine volume was correlated with the urethral resistance (P <
UROLOGY
/ DECEMBER1982
/ VOLUMEXX,NUMBER6
I
I
,
I
0
100
200
300
/-A0
ML FIGURE 1. Distribution of postvoid residual urine volumes in 47 patients with prostatism.
0.02) and the symptoms of intermittency (P < 0.025) but not with any other symptomatic, cystoscopic, or urodynamic parameters. No correlation was noted between preoperative residual volume and the patient’s own estimation of his postoperative outcome. Comment Information on postvoid residual urine volume and residual urine volume in normal elderly males is sparse,’ making studies of the significance of residual urine volume in prostatism difficult. Cote, Burke, and Schoenberg2 noted that patients with prostatism and normal preoperative cystometrograms tended to have greater postvoid residual urine volumes than patients with prostatism and preoperative UDC.2 Andersen, Nordling, and Walter3 found that residual urine was correlated to the symptom urge and sense of incomplete bladder emptying and found a correlation between the duration of symptoms and the residual urine volume. They further noted that elevated urethral resistance correlated with postvoid residual urine determination, but found no correlate between maximum flow and the symptoms of frequency,
603
nocturia, pain, the force of the urinary stream, or urge incontinence. Abrams and Griffiths4 and Turner-Warwick et ~1.~ believed that elevated residual urine reflected bladder dyshnction rather than obstruction. We would agree that residual urine determination probably reflects bladder dysfunction, but we were not able to correlate it with the finding of UDC, urethral resistance, maximum urine flow rate, or any preoperative symptoms. The fact that there was wide individual variation in residual urine determinations implies that a single measurement of residual urine volume following spontaneous flow in and of itself may not be reproducible, leading us to conclude that not too much emphasis should be placed on a single determination. While transurethral resection of the prostate is frequently performed to reduce residual urine, particularly in a patient presenting with a history of lower urinary tract infection, we cannot identify an association between the volume of residual urine and infection. However, the only way to establish clearly the relationship between residual urine volume and urinary tract infection would be to compare the incidence of infection in two groups of agematched males with and without elevated residual urine volume. Unfortunately no such data are available.
604
While residual urine was significantly reduced after transurethral resection of the prostate in our patients, we cannot advocate residual urine determination as a tool for assessing the degree of prostatic obstruction, nor could we find any correlation between preoperative residual urine determination and postoperative outcome. Its value in preoperative evaluation of prostatism as a predictor of postoperative outcome is questionable. Clinical Science Center Madison, Wisconsin 53792 (DR. BRUSKEWm) To Ms. Karen Scott for assistance ACKNOWLEDGMENT. in the preparation of this manuscript.
References 1. Andersen JT, Jacobsen 0, Worm-Petersen J, and Hald T: Bladder function in healthy elderly males, Stand J Urol Nephrol 12: 123 (1978). 2. Cote RJ, Burke H, and Schoenberg HW: Prediction of unusual postoperative results by urodynamic testing in benign prostatic hyperplasia, J Ural 125: 690 (1980). 3. Andersen JT, Nordling J, and Walter S: Prostatism. I. The correlations between symptoms, cystometric, and urodynamic findings, Stand I Urol Neohrol 13: 229 (1979). 4. ibrams PI$ and G&ths DJ: T& assessment of prostatic obstruction from urodynamic measurements and from residual urine, Br J Ural 51: 129 (1979). 5. Turner-Warwick R, et al: A urodynamic view of prostatic obstruction and the results of prostatectomy, ibid 45: 631 (1973).
UROLOGY
/
DECEMBER
1982
!
VOLUME
XX, NUMBER
6