Does a nerve-sparing technique or potency affect continence after open radical retropubic prostatectomy?

Authors


Herbert Lepor, Professor and Martin Spatz Chairman, Department of Urology, NYU School of Medicine, 150 East 32nd Street – 2nd Floor, New York, NY 10016, USA.
e-mail: herbert.lepor@med.nyu.edu

Abstract

OBJECTIVE

To characterize the effect of preserving the neurovascular bundle (NVB) and of potency on urinary continence after open radical retropubic prostatectomy (ORRP).

PATIENTS AND METHODS

Between October 2000 to September 2005, 1110 consecutive continent men had ORRP by one surgeon. The University of California Los Angeles Prostate Cancer Index was self-administered at baseline and 3, 6, 12, and 24 months after ORRP. Men were considered continent if they responded that they had total urinary control or had occasional urinary leakage. Men were considered potent if they engaged in sexual intercourse with or without the use of phosphodiesterase inhibitors at least once in the month before or after ORRP. Of the 1110 men, 728 (66%) were potent and continent at baseline. Men undergoing adjuvant hormonal therapy, radiation therapy or chemotherapy were excluded. The potency status was evaluated in 610 men at 24 months after ORRP, and the number of NVBs preserved was recorded at the time of ORRP.

RESULTS

Of men who were potent at baseline and had bilateral vs unilateral nerve sparing, 96% and 99% were continent at 24 months, respectively (P = 0.50). Of the men who were potent and impotent at 24 months, 98% and 96% were continent at 24 months, respectively (P = 0.25). Continence did not depend on whether men regained potency or whether they had a bilateral or a unilateral nerve-sparing procedure.

CONCLUSION

Our observation that only 60% of men undergoing bilateral nerve-sparing ORRP regain potency suggests that the NVBs are often inadvertently injured, despite efforts to preserve them. We feel that potency status is the best indicator of the true extent of NVB preservation. That men undergoing bilateral vs unilateral nerve-sparing procedures, and that potent vs impotent men at 24 months have similar continence rates, provides compelling evidence that nerve-sparing is not associated with better continence. Based on these findings, NVBs should not be preserved in men with baseline erectile dysfunction, with the expectation of improving continence.

Abbreviations
(OR)RP

(open retropubic) radical prostatectomy

NVB

neurovascular bundle

UCLA-PCI

University of California Los Angeles Prostate Cancer Index

AUASS(I)

AUA Symptom Score (Index)

BMI

body mass index

LUTS

lower urinary tract symptoms

INTRODUCTION

It is generally agreed that stress urinary incontinence after radical prostatectomy (RP) is attributed to a dysfunctional rhabdosphincter [1]. The rhabdosphincter is composed of both smooth and skeletal muscle [2] and therefore, injury to its autonomic innervation might cause stress incontinence. Donker and Walsh [3] showed in fetal dissections that the cavernous nerve provides some innervation to the rhabdosphincter. It is therefore plausible that one of the secondary benefits of nerve-sparing RP is improved urinary continence. There is currently conflicting evidence whether preserving the neurovascular bundles (NVBs) is associated with improved urinary continence after RP (Table 1) [4–10]. Wei et al.[11] reported that the time to recover continence depends on age and cavernous nerve preservation. The series we report here is the only study using self-administered validated questionnaires that were administered both before and after RP to ascertain the relationship between nerve-sparing surgery and potency outcomes as a predictor of urinary continence after RP.

Table 1.  Studies evaluating potency and/or nerve-sparing effects on continence after ORRP
VariableStudy
Present[4][5][6][7][8][9][10]
  1. NS, nerve-sparing. *Potency status was known for 559 patients and continence status was known for 593 patients. †603 patients had RP and 372 had a follow-up at 24 months. ‡The validated questionnaires were not self-administered; §Three definitions were used for continence in this series; the presented continence rate is for the least stringent definition, and this overall continence rate is for the entire 985 patients, but data on surgical technique were only available for 560. ¶Seven patients had ‘No NS’, and of those six were continent.

No. of patients610593*37253656027371325581
Validated questionnaire?YesNoYesNoYesNoNoNo
% Continent
 Potent 98 94
 Impotent 96 90
 Significant (P < 0.05)NoNo
 Overall 97 9294.293.4§ 93 92 91
 No NS 8186.3
 Unilateral NS 99 9296.6
 Bilateral NS 96 9498.7
 Significant (P < 0.05)NoNoNoYesYesNoNoYes

PATIENTS AND METHODS

Between October 2000 to September 2005, 1110 consecutive men underwent open retropubic RP (ORRP) by one surgeon, using a previously described surgical technique [12]. The University of California Los Angeles (UCLA) Prostate Cancer Index (PCI) [13] and AUA Symptom Index (AUASI) [14] were self-administered at baseline and 3, 6, 12, and 24 months after ORRP. Men were considered potent before ORRP if they responded that they engaged in sexual intercourse at least once in the month before ORRP. Men were considered continent before and after ORRP if they responded that they had total urinary control or occasional urinary dribbling. Of the 728 men who were continent and potent at baseline, 610 (84%) did not have adjuvant hormonal therapy, radiation therapy or chemotherapy, and completed the UCLA-PCI and AUASI at 24 months. The outcome assessment at 24 months also recorded whether men were using intracavernosal injections, vacuum devices, and intraurethral suppositories to achieve sexual intercourse, and whether they had a sexual partner. Men were not considered potent after ORRP if they were using any of these treatments for sexual intercourse. Only those patients without a sexual partner were considered potent if they responded that they were experiencing erections felt to be satisfactory for intercourse.

All prostatic biopsy slides were re-assessed by a Medical Center staff pathologist at the authors’ institution. The patients’ body mass index (BMI) was determined after ORRP, and a complete blood count was routinely determined immediately before the induction of anaesthesia, upon arrival into the recovery room and the morning after ORRP. Blood loss during ORRP was estimated by subtracting the recovery room haematocrit from the induction haematocrit before anaesthesia. The blood loss after ORRP was calculated by subtracting the haematocrit at discharge from that assessed in the recovery room. Three haematocrit points were added to the calculated blood loss during and after ORRP for any unit of autologous or allogeneic blood that was transfused during or after surgery, respectively. Gravity cystography was performed as previously described [15]; the initial cystogram was taken at 7 days after ORRP (between February 2000 and December 2000), at 3 or 4 days after (between January 2001 and August 2001) or 8 days after (between September 2001 and September 2005).

Beginning in January 2001, the decision to use side-specific nerve-sparing ORRP was based on an established algorithm before ORRP [16]. Before this date, the decision for nerve sparing was at the discretion of the surgeon. Immediately after completing the ORRP a case-log was completed by the resident surgeon indicating whether the ORRP was bilateral, unilateral, or not nerve-sparing; these data were immediately extracted into the prospective computer database.

RESULTS

The baseline characteristics for the 1110 men undergoing ORRP between October 2000 to September 2005, and the subset of 610 of these continent and potent men at baseline completing the UCLA-PCI and AUASI at 24 months, are presented in Table 2. The small but statistically significant difference in age is consistent with younger men being more likely to be potent at baseline. The evaluable subset of men at 24 months had significantly lower-risk disease (lower preoperative serum PSA levels and Gleason scores).

Table 2.  Baseline characteristics of the present series
CharacteristicAll patients (1110)Evaluable men (610)P
  • *

    Student’s t-test;

  • †chi-square test.

Mean (sem):
Age, years58.4 (0.20)57.2 (0.26)<0.001*
BMI, kg/m227.2 (0.13)27.0 (0.18)0.430*
Serum PSA level, ng/mL6.46 (0.16)5.95 (0.19)0.049*
AUASI7.25 (0.19)6.79 (0.25)0.150*
% Patients:
Clinical stage
 T186880.14
 T21412 
Gleason score
 ≤65559 
 740390.010
 ≥8 5 2 

Overall, 97% and 64% of men regained urinary continence and were engaging in sexual intercourse at 24 months, respectively. The 12% of these men who were dependent on intracavernosal injections to achieve sexual intercourse were not considered potent after ORRP, but the 6% of men with no sexual partner who responded that their erections were adequate for sexual intercourse were considered potent; overall, 59% were considered potent after surgery.

Overall, 88% and 12% of men had bilateral or unilateral nerve-sparing, respectively. Age, BMI, baseline AUA Symptom Score (AUASS), blood loss during and after ORRP, moderate or severe extravasation on an initial postoperative cystogram, and cardiovascular risk factors might affect continence after ORRP. Therefore, we compared these potential confounders of continence for men undergoing unilateral vs bilateral nerve-sparing ORRP (Table 3); most of these factors were not significantly different among the two groups, but there was a significant difference in age between the groups. Men having a bilateral nerve-sparing ORRP were significantly younger than the unilateral group. However, if this small but statistically significant difference in age led to bias in the study, it would probably result in a better continence rate for the bilateral nerve-sparing group, which was not apparent in the results.

Table 3.  Comparison of potential factors influencing continence rates according to nerve sparing status
VariableNerve-sparingP
Bilateral (538)Unilateral (72)
  • *

    Student’s t-test;

  • Mann–Whitney test;

  • ‡chi-square test.

  • §

    §Cardiovascular risk factors included a history of coronary artery disease, hypertension, dyslipidaemia, tobacco smoking, and diabetes mellitus; patients with one or more risk factor were included.

Mean (sem):
Age, years 56.9 (0.28) 59.4 (0.68)0.002*
BMI, kg/m2 27.0 (0.19) 27.1 (0.49)0.84*
AUASI  6.7 (0.22)  7.5 (0.81)0.31*
Blood loss (change in haematocrit)
 During ORRP−13.0 (0.22)−12.9 (0.56)0.80
 After ORRP −2.2 (0.17) −2.2 (0.41)0.88
% Patients:
Moderate/severe extravasation on initial cystogram  8 100.57
Cardiovascular risk factors§ 56 620.31

The continence and potency rates at 24 months were compared for the 610 men who were both potent and continent before ORRP, according to whether they had unilateral or bilateral nerve-sparing (Table 4). Men who had bilateral nerve-sparing ORRP were more likely to be potent than men having a unilateral procedure. Continence rates and the percentage of men showing total control at 24 months were independent of nerve-sparing status. Continence rates at 24 months were also compared for men who were potent and impotent at 24 months; the continence rates and the percentage of men with total control were also independent of potency status at 24 months.

Table 4. 
Relationship between nerve sparing, potency rates and continence rates, at 24 months
Group% Total control% Continent% Potent
  1. Pearson’s chi-square test was used for all analyses.

Nerve sparing
 Bilateral (538)569660
 Unilateral (72)549944
P 0.75 0.50 0.011
Potency status
 Potent (357)5898
 Impotent (253)5396
P 0.29 0.25

DISCUSSION

The development of incontinence after RP is of great concern for men so treated [17,18]; fortunately, the overwhelming majority of men who undergo RP by experienced surgeons regain continence [4–10]. The present continence rate of 97% at 24 months is similar to outcomes reported by other experienced surgeons [4–10]. We previously showed that all men reporting occasional dribbling at 24 months considered themselves continent [19]; 12% of men before surgical intervention reported occasional dribbling. These previous observations justify considering men with occasional dribbling as continent.

We previously reported that no preoperative factors reliably predict those surgical candidates who are at a higher risk of developing stress incontinence after RP [20]. Others reported that age is a predictor of final continence status [7–10,21]; nevertheless, even the oldest of men undergoing RRP are likely to ultimately regain urinary control. In the present series, 93% of men aged >65 years were continent at 24 months (data not shown).

There is some controversy as to whether preserving the NVBs improves urinary incontinence. The greater continence rates in men undergoing bilateral vs unilateral nerve-sparing RP has not been a consistent observation (Table 1) [4–10]. The primary objective of the present study was to determine if preserving the cavernous nerves influenced continence rates and the percentage of men with total control. We compared potential baseline or technical confounders of continence in men undergoing bilateral or unilateral nerve-sparing ORRP to be confident that one group was not predisposed to develop incontinence. Age, BMI, baseline LUTS, blood loss and the integrity of the anastomosis on the initial postoperative cystogram were not significantly different between the nerve-sparing groups. Our study supports others that failed to detect a significant difference in continence rates, or that showed differences in total control between men undergoing bilateral or unilateral nerve-sparing ORRP.

Not all potent men undergoing bilateral nerve-sparing RP will ultimately have preserved potency. Potency rates reported by experienced surgeons for men undergoing bilateral nerve-sparing RP are 44–86%[8,9,22–27]. The present overall potency rate of 59% is consistent with other large individual series. These potency rates indicate that the intent to perform a nerve-sparing RP does not mean the nerves were adequately preserved to restore erectile function. We think that potency status is a better indicator of the degree of actual cavernous nerve preservation than simply whether there was an intention to spare the NVBs. That continence was not significantly different in men who were potent or impotent after RP provides further evidence that successful preservation of cavernous nerves does not favourably affect continence.

In conclusion, preserving the NVB affects potency and not continence rates in men undergoing ORRP. From the present results, the decision to perform a nerve-sparing RP should be based on cancer control and erectile function, and not continence.

CONFLICT OF INTEREST

None declared.

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