Intraoperative Distal Vasal Flushing Doe (6)
Infertility
Intraoperative Distal Vasal Flushing—Does
It Improve the Rate of Early Azoospermia
Following No-scalpel Vasectomy? A
Prospective, Randomized, Controlled Study
Dharamveer Singh, Nandan S. Dasila, Pawan Vasudeva, Divakar Dalela,
Satyanarayan Sankhwar, Apul Goel, Vishwajeet Singh, Anjana Singh, Abhishek Jain,
Bhupendra P. Singh, and Nisar Ahmed
OBJECTIVE
MATERIAL AND
METHODS
RESULTS
CONCLUSIONS
To assess the impact of intraoperative distal vasal flushing during no-scalpel vasectomy on
hastening the sperm clearance from the vas deferens and subsequent postvasectomy time to
azoospermia.
A total of 906 men undergoing vasectomy at our center from October 2007 to August 2008 were
included in this prospective, randomized, controlled study. Patients were alternately allocated to
1 of 2 groups. Group A were patients who underwent no scalpel vasectomy alone; Group B
patients, in addition to no scalpel vasectomy, underwent flushing of the distal vasal segment with
30 mL of sterile water. Postvasectomy semen analysis was done at 4, 8, and 12 weeks. The age,
operative time, number of ejaculations, and proportion of patients’ azoospermic at 4, 8, and 12
weeks after vasectomy were compared between the 2 groups.
A total of 727 men were available for final analysis. A significantly higher proportion of patients
in group B were azoospermic at 4 and 8 weeks when compared with group A (group B: 53.40%
and 80.68%; group A: 33.86% and 49.6% at 4 and 8 weeks, respectively). There was no
statistically significant difference in the mean age, operative time, and number of ejaculations
between the 2 groups.
Distal vasal flushing with 30 mL of sterile water may shorten the time to azoospermia for between
20% and 30% of vasectomy patients. Thus, this procedure may be an option for some who choose the
vasal flush to avoid the long duration of postvasectomy alternate contraceptive methods. UROLOGY
76: 341–346, 2010. © 2010 Elsevier Inc.
A
lthough no-scalpel vasectomy (NSV) is an easy,
safe, cost-effective, and reliable method of male
contraception, a potential drawback of the procedure is that the patient does not become infertile
immediately after surgery but does so after a variable time
lag, necessitating the use of an alternate contraceptive
method for a variable period. This delay has been attributed to the time it takes for clearance of sperm residing in
the distal vas.1 Various authors have tried to accelerate
the onset of azoospermia by distal vasal flushing at the
time of NSV using various solutions. These are thought to
act by mechanical flushing and, in the case of sterile
water, additional modes of action, including sperm lysis
From the Centre of Excellence for No-Scalpel Vasectomy; and Department of Urology,
CSM, Medical University (Upgraded King George’s Medical College), Uttar Pradesh,
India
Reprint requests: Dr. Dharamveer Singh, Centre of Excellence for no-scalpel vasectomy, Department of Urology, CSM, Medical University (Upgraded King George’s
Medical College), Lucknow-226 003, UP, India. E-mail: drdharamveersingh@yahoo.
co.in; [email protected]
© 2010 Elsevier Inc.
All Rights Reserved
via an osmotic effect and immobilization of the sperms,
have been proposed.2 Currently, no consensus exists on the
usefulness of distal vasal flushing as an adjunct to traditional NSV. The purpose of this study was to assess the
impact of intraoperative distal vasal flushing on hastening the sperm clearance from the vas deferens and subsequent time to azoospermia after vasectomy.
MATERIAL AND METHODS
This study was undertaken after approval from the institutional
ethics committee. Consecutive patients undergoing NSV at our
center from October 2007 to August 2008 were included in this
prospective, randomized, controlled study, with blinding of
both the participants and the outcome assessor. Surgeons were
not blinded. Exclusion criteria included (a) patients who did
not adhere to the post-NSV evaluation protocol as described
later, and (b) patients who did not give consent for the study.
Included patients were alternately allocated to one of the 2
groups, and sequentially numbered, opaque, sealed envelopes
were used for allocation concealment.
0090-4295/10/$34.00
doi:10.1016/j.urology.2010.01.091
341
Vasectomy Technique
Group A (control group) underwent NSV as described by Li et
al. along with segmental excision of vas and fascial interposition
between the suture ligated cut ends.3 Group B (intervention
group), in addition to NSV, underwent bilateral flushing of the
distal vas. This was accomplished on each side by gently pushing in 30 mL of sterile water via a 20-G intravenous cannula
inserted for a distance of about 1.5 cm through the open cut end
of the distal vas. Once flushing was completed, the distal vas
was ligated just beyond the cannula and the segment of distal
vas proximal to the ligature was excised. Vasectomy in both
groups was performed under local anesthesia by 3 experienced
surgeons (certified NSV trainers).
Semen Analysis. Evaluation protocol in the follow-up period
consisted of semen analysis at 4, 8, and 12 weeks after NSV,
irrespective of the findings of semen analysis. The participants
were asked to produce a semen sample in a private room at the
laboratory. Semen samples were examined within 1 hour of
collection. An aliquot was examined by phase-contrast microscopy at high-power magnification (400x) to estimate sperm
concentration. Based on the estimated concentration, dilutions
were prepared to assess exact sperm concentration and motility.
The concentration and motility of each sample were determined using a Neubauer hemocytometer. Samples with no
sperm (azoospermia) on the initial unspun semen analysis were
centrifuged for 15 minutes at 600 g and then reassessed for
sperm concentration and motility as described before.
Study Outcomes. The primary outcome measure was azoospermia (no detectable sperm on spun semen analysis), either as the
rate at postvasectomy follow-up visits or the time to azoospermia. Secondary outcomes included were the incidence of intermittent sperm reappearance in the ejaculate after a period of
azoospermia, number of ejaculations, operating time, and adverse events. Further, patients were instructed to record all
episodes of ejaculation post-NSV for a period of 12 weeks. The
2 groups were compared with regard to age, operative time,
number of ejaculations, frequency and type of complications,
and the proportion of patients azoospermic at 4, 8, and 12 weeks
after NSV. For the purpose of this study, all patients whose
semen sample was negative for sperm (azoospermia) at 4 and/or
8 weeks still underwent semen analysis at 12 weeks to see the
incidence of early intermittent reappearance of sperm.
Sample Size Estimation and Statistical Analysis Methods. An
a priori sample size calculation was done and our plan was to
enroll at least 300 participants in each group to get 80% power
to detect a difference between the groups, with a two-sided test
and an alpha of 0.05. Data analysis was done using SPSS
software (version 11.5, SPSS, Inc., Chicago, IL) and a twosided P value of ⬍0.05 was considered statistically significant.
Fisher’s exact test was used for comparisons of the dichotomous
(azoospermia) variables and Welch’s corrected t-test was used to
compare the means.
RESULTS
A total of 1566 men underwent NSV during the study
period. Of these, 906 patients gave consent for the study.
One-hundred seventy-nine (19.76%) of the 906 men
were subsequently excluded because of nonadherence to
the follow-up evaluation protocol, leaving 727 (80.24%)
342
Figure 1. Study participant disposition flow chart.
men (group A: 375 men; group B: 352 men) available for
final analysis (Fig. 1). Mean age, mean operative time,
and mean frequency and type of complications did not
differ significantly between the 2 groups. Complications
were hematoma, infection, chronic orchalgia, palpable
nodule (sperm granuloma), and dissatisfaction with surgery. None of the patients in both groups complained of
symptoms suggestive of “clinical” prostatitis, such as fever, dysuria, and voiding or storage lower urinary tract
symptoms. Two patients in group B and 1 patient in
group A complained of self-limiting painful ejaculation
between days 5 and 9; however, none had clinical hematospermia. A transient desire to urinate was described by
most patients in the irrigation group.
A significantly higher proportion of patients in group B
were azoospermic at 4 and 8 weeks when compared with
group A (group B: 53.40% and 80.68%; group A: 33.86%
and 49.6% at 4 and 8 weeks, respectively). The proportion of azoospermic patients at 12 weeks did not differ
significantly between the 2 groups. The mean number of
ejaculations at 4, 8, and 12 weeks did not differ significantly between the 2 groups (Table 1).
COMMENT
Although NSV is rapidly gaining in acceptance as a
contraceptive method, the delay in achieving “infertile
status” is a factor that affects the patient acceptability of
the procedure. Further, a major cause of vasectomy failure/unwanted pregnancy, especially in developing countries, is an ill-informed or negligent patient who assumes
that he is sterile shortly after the procedure. Any method
that would help in achieving rapid sperm clearance
would in part address the those issues.
UROLOGY 76 (2), 2010
Table 1. Comparison of variables and results of semen analysis between group A and B
Variable
Age (years)
Mean ⫾ SD
Median (range)
Operative time (min.)
Mean ⫾ SD
Median (range)
Azoospermic patients (%)
4 wks
8 wks
12 wks
Mean number of ejaculations ⫾ SD
4 wks
8 wks
12 wks
Group A (n ⫽ 375)
P Value
.41
32.4 ⫾ 5.68
31 (25-47)
32.09 ⫾ 4.51
31 (24-45)
8.76 ⫾ 2.13
8 (6-14)
9.03 ⫾ 1.92
9 (7-17)
127 (33.86)
186 (49.6)
352 (93.86)
188 (53.4)
284 (80.68)
341 (96.87)
⬍.0001
.0001
.08
11.48 ⫾ 2.98
20.48 ⫾ 3.85
32.78 ⫾ 5.5
11.75 ⫾ 2.62
20.7 ⫾ 3.69
33.55 ⫾ 5.47
.194
.43
.06
.07
Currently, there is little consensus about whether
flushing of the distal vas helps to achieve azoospermia
earlier. Sommer et al, in a study of 59 patients, used 40
mL of sterile water for vasal flushing and reported a
significantly shorter time to azoospermia.4 Roshani et al,
in a study of 126 patients, also reported significantly
higher azoospermic rates of 100% at 12 weeks and 88.1%
at 16 weeks in patients who underwent distal vasal flushing with 40 mL of sterile water and saline solution,
respectively, when compared with patients in whom vasal flushing was not used (26.2% azoospermic at 16
weeks).5 In contrast, studies by Mason et al (200 men
undergoing vasectomy with or without vasal lavage using
10 mL of sterile water) and Eisner et al (106 men undergoing vasectomy with or without vasal flush using 10 mL
of normal saline) failed to demonstrate any benefit of
distal vasal flushing insofar as hastening azoospermia was
concerned.2,6 Although it may be argued that these 2
studies may not have been able to demonstrate a significant difference in outcomes because the quantity of fluid
used to flush the vas was suboptimal in both (10 mL), a
nonrandomized, controlled study of 72 patients by Pearce
et al, in which 50 mL of normal saline was used for vasal
flushing, also did not demonstrate any benefit in terms of
hastening azoospermia.7 In addition, the possible explanation could be that all of these trials were poor quality
and relatively small and therefore underpowered. None
of the previously cited studies mentioned about the
method of semen analysis (spun vs unspun sample), except Mason et al, used a centrifuged semen sample for
postvasectomy semen analysis.
Another reason for discrepancies between the results
of various studies may be that these studies did not take
into account the number of ejaculations during the follow-up period, because time to infertility also depends on
the frequency of postoperative ejaculations.4 The number
of ejaculations after NSV is also important in addition to
the time period to achieve azoospermia; approximately
80% of patients are azoospermic after 3 months and after
about 20 ejaculations.8 In our study, the mean number of
UROLOGY 76 (2), 2010
Group B (n ⫽ 352)
ejaculations between the 2 groups did not differ significantly at any point in the follow-up and hence it seems
reasonable to presume that it was the vasal flushing that
resulted in a significantly higher percentage (between
20% and 30%) of patients being azoospermic at 4 and 8
weeks postvasectomy.
Another area of controversy is when to label a man
infertile after NSV. There is no absolute standard of care
when it comes to declaring a patient sterile. Follow-up
semen analysis at least 2-3 months after vasectomy, with
the goal of obtaining at least 1, and preferably 2, absolutely azoospermic specimens 4-6 weeks apart, is recommended.8-11 Because intermittent reappearance of sperm
usually occurs early after vasectomy, for the purpose of
this study, patients whose semen sample was negative for
sperm at 12 weeks were finally considered infertile. For
those who achieved azoospermia earlier, subsequent samples as per protocol were still taken to ensure that the
patient’s semen remained sperm-negative. The study end
point was taken as completion of 12 weeks’ follow-up
after NSV regardless of azoospermic status. Three patients in group A and 2 patients in group B whose semen
sample was negative for sperm at 4 weeks had reappearance of sperm during semen analysis at 8 weeks. Semen
analysis at 12 weeks showed that all 5 patients again
became azoospermic, so they were considered infertile,
the timing of infertility being taken as 12 weeks in all 5.
One patient in group A who had a semen sample negative for sperm at 8 weeks showed sperm in his semen
sample at 12 weeks and was considered not to have
become infertile as per study protocol. Thus, reappearance of sperm was seen in 6 patients during the whole
follow-up period of 12 weeks. It is controversial whether
this early intermittent reappearance of motile sperm in
semen is the result of transient early recanalization or
residual sperm in the distal vas. Regarding vas irrigation,
some experts believe that the presence of motile sperm in
semen after 4-6 weeks is more likely to be the result of
transient early recanalization rather than residual sperm
in the distal vas.12 The chances of recanalization are less
343
when fascial interposition is used along with excision and
ligation of vas, because an international multicenter trial
of vasectomy with and without fascial interposition demonstrated a 2-fold reduction in failure rates using fascial
interposition.13 Although uncommon, the late failure
rate has been reported to be 0.04%-0.08%, and recanalization is usually only discovered after pregnancy in the
female partner.14 However, so far we have not received
report of any pregnancy.
The findings of azoospermia differ in the whole semen
(unspun) versus the spun specimen. The laboratory should
examine a freshly produced seminal fluid specimen by
direct microscopy and if no sperm are seen, the centrifuged sample should be examined for the presence of
motile and nonmotile spermatozoa.15 Semen centrifugation should be performed in all men considered to have
azoospermia by routine semen analysis because studies
have demonstrated the presence of motile and nonmotile
sperm in a significant number of men considered to have
azoospermia by routine semen analysis.16
Our study shows that distal vasal flushing with sterile
water does shorten the time to azoospermia in a statistically significant number (between 20% and 30%) of
patients at 4 and 8 weeks after NSV. For developing
countries, it may also be important from an economic
point of view, to reduce the 1-month cost of barrier
methods because semen analysis at 8 weeks was negative
for sperm in more than 80% of cases of vasal flushing.
Vasal flushing may also reduce, to some extent, the
chances of unwanted pregnancies in uneducated, poor,
and neglected communities of developing countries in
addition to increasing the acceptance rate for vasectomy.
Although no formal survey was conducted regarding
whether the difference of 4 weeks had any importance to
these patients in choosing vasectomy, the clients often
raised concerns about the long duration of postvasectomy
condom usage. After this study, our current “clinical”
protocol for post-NSV semen analysis is a single semen
analysis at 8 weeks. If the patient is sterile (azoospermic
on spun semen analysis) at 8 weeks, we do not pursue
further semen analysis in these patients and an additional
semen analysis is done monthly until azoospermia is
achieved or up to 6 months in patients who had sperm in
their semen samples at 8 weeks.
To our knowledge, this is the largest reported randomized,
controlled trial addressing the issue of the effect of distal vasal
flushing on the time taken to achieve azoospermia. Limitation
of our study is lack of long-term follow-up and a high rate of
exclusion (19.76%) after randomization because of nonadherence to the follow-up evaluation protocol. Loss to follow-up
rates greater than 20% may threaten the validity of trials.17
Patient compliance decreases significantly with each subsequent visit for post-NSV semen analysis,10 thus, in our opinion
the overall compliance rate of more than 80% in the present
study is not unacceptably high. Although extremely rare, there
is some theoretical risk that the catheter itself might create risk
of recanalization by damaging the vas. Another theoretical
344
concern is the risk of seminal vesiculitis, prostatitis, and inflammation inside the lumen of the distal vas, which may compromise the luminal patency of the abdominal vas during future
vasectomy reversal. Finally, because these results are based on 1
large trial, the evidence would be stronger if confirmed by a
second trial.
CONCLUSIONS
Distal vasal flushing with 30 mL of sterile water may shorten
the time to azoospermia to between 20% and 30% of vasectomy patients. Thus, this procedure may be an option for
some who choose the vasal flush to avoid the long duration
of postvasectomy alternate contraceptive methods.
References
1. Sukapiriya C, Chanpalakorn N, Chalermsanyakorn P, et al. Sites of
residual spermatozoa after irrigation of the distal vas deferens using
normal saline solution during vasectomy in a rat model. Int J
Androl. 2005;28(4):230-233.
2. Mason RG, Dodds L, Swami SK. Sterile water irrigation of the
distal vas deferens at vasectomy: does it accelerate clearance of
sperm? A prospective randomized trial. Urology. 2002;59:424-427.
3. Li SQ, Goldstein M, Zhu J, et al. The no-scalpel vasectomy. J Urol.
1991;145:341-344.
4. Sommer F, Eusan A, Caspers HP, et al. Effect of flushing the vasa
deferentia at the time of vasectomy on the rate of azoospermia. BJU
Int. 2001;88(Suppl 1):9.
5. Roshani A, Falahatkar S, Khosropanah I, et al. Vasal irrigation
with sterile water and saline solution for acceleration of postvasectomy azoospermia. Urol J. 2008;5:37-40.
6. Eisner B, Schuster T, Rodgers P, et al. A randomized clinical trial
of the effect of intraoperative saline perfusion on postvasectomy
azoospermia. Ann Fam Med. 2004;2:221-223.
7. Pearce I, Adeyoju A, Bhatt RI, et al. The effect of perioperative
distal vasal lavage on subsequent semen analysis after vasectomy: a
prospective randomized controlled trial. BJU Int. 2002;90:282-285.
8. Griffin T, Tooher R, Nowakowski K, et al. How little is enough?
The evidence for postvasectomy testing. J Urol. 2005;174:29-36.
9. Barone MA, Nazerali H, Cortes M, et al. A prospective study of
time and number of ejaculations to azoospermia after vasectomy by
ligation and excision. J Urol. 2003;170:892-896.
10. Badrakumar C, Gogoi NK, Sundaram SK. Semen analysis after
vasectomy. When and how many? BJU Int. 2000;86:479-481.
11. Sivardeen KA, Budhoo M. Post vasectomy analysis: call for a uniform
evidence-based protocol. Ann R Coll Surg Engl. 2001;83:177-179.
12. Cook LA, Van Vliet HAAM, Lopez LM, et al. Vasectomy occlusion
techniques for male sterilization. Cochrane Database Syst Rev. 2009;
issue 3;Art. No. CD003991. [10.1002/14651858.CD003991.pub3].
13. Sokal D, Irsula B, Investigator Study Group, et al. Vasectomy by
ligation and excision, with or without fascial interposition: A randomized controlled trial [ISRCTN77781689]. BMC Med. 2004;2:6.
14. Alderman PM. The lurking sperm. A review of failures in 8879
vasectomies performed by one physician. J Am Med Assoc. 1988;
259:3142-3144.
15. Hancock P, McLaughlin E. British Andrology Society guidelines
for the assessment of post vasectomy semen samples. J Clin Pathol.
2002;55:812-816.
16. Jaffe TM, Kim ED, Hoekstra TH, Lipshultz LI. Sperm pellet analysis: A technique to detect the presence of sperm in men considered to have azoospermia by routine semen analysis. J Urol. 1998;
159:1548-1550.
17. Strauss SE, Richardson WS, Glasziou P, et al. Evidence-Based Medicine: How to Practice and Teach EBM, 3rd ed. New York: Churchill
Livingstone; 2005.
UROLOGY 76 (2), 2010
Intraoperative Distal Vasal Flushing—Does
It Improve the Rate of Early Azoospermia
Following No-scalpel Vasectomy? A
Prospective, Randomized, Controlled Study
Dharamveer Singh, Nandan S. Dasila, Pawan Vasudeva, Divakar Dalela,
Satyanarayan Sankhwar, Apul Goel, Vishwajeet Singh, Anjana Singh, Abhishek Jain,
Bhupendra P. Singh, and Nisar Ahmed
OBJECTIVE
MATERIAL AND
METHODS
RESULTS
CONCLUSIONS
To assess the impact of intraoperative distal vasal flushing during no-scalpel vasectomy on
hastening the sperm clearance from the vas deferens and subsequent postvasectomy time to
azoospermia.
A total of 906 men undergoing vasectomy at our center from October 2007 to August 2008 were
included in this prospective, randomized, controlled study. Patients were alternately allocated to
1 of 2 groups. Group A were patients who underwent no scalpel vasectomy alone; Group B
patients, in addition to no scalpel vasectomy, underwent flushing of the distal vasal segment with
30 mL of sterile water. Postvasectomy semen analysis was done at 4, 8, and 12 weeks. The age,
operative time, number of ejaculations, and proportion of patients’ azoospermic at 4, 8, and 12
weeks after vasectomy were compared between the 2 groups.
A total of 727 men were available for final analysis. A significantly higher proportion of patients
in group B were azoospermic at 4 and 8 weeks when compared with group A (group B: 53.40%
and 80.68%; group A: 33.86% and 49.6% at 4 and 8 weeks, respectively). There was no
statistically significant difference in the mean age, operative time, and number of ejaculations
between the 2 groups.
Distal vasal flushing with 30 mL of sterile water may shorten the time to azoospermia for between
20% and 30% of vasectomy patients. Thus, this procedure may be an option for some who choose the
vasal flush to avoid the long duration of postvasectomy alternate contraceptive methods. UROLOGY
76: 341–346, 2010. © 2010 Elsevier Inc.
A
lthough no-scalpel vasectomy (NSV) is an easy,
safe, cost-effective, and reliable method of male
contraception, a potential drawback of the procedure is that the patient does not become infertile
immediately after surgery but does so after a variable time
lag, necessitating the use of an alternate contraceptive
method for a variable period. This delay has been attributed to the time it takes for clearance of sperm residing in
the distal vas.1 Various authors have tried to accelerate
the onset of azoospermia by distal vasal flushing at the
time of NSV using various solutions. These are thought to
act by mechanical flushing and, in the case of sterile
water, additional modes of action, including sperm lysis
From the Centre of Excellence for No-Scalpel Vasectomy; and Department of Urology,
CSM, Medical University (Upgraded King George’s Medical College), Uttar Pradesh,
India
Reprint requests: Dr. Dharamveer Singh, Centre of Excellence for no-scalpel vasectomy, Department of Urology, CSM, Medical University (Upgraded King George’s
Medical College), Lucknow-226 003, UP, India. E-mail: drdharamveersingh@yahoo.
co.in; [email protected]
© 2010 Elsevier Inc.
All Rights Reserved
via an osmotic effect and immobilization of the sperms,
have been proposed.2 Currently, no consensus exists on the
usefulness of distal vasal flushing as an adjunct to traditional NSV. The purpose of this study was to assess the
impact of intraoperative distal vasal flushing on hastening the sperm clearance from the vas deferens and subsequent time to azoospermia after vasectomy.
MATERIAL AND METHODS
This study was undertaken after approval from the institutional
ethics committee. Consecutive patients undergoing NSV at our
center from October 2007 to August 2008 were included in this
prospective, randomized, controlled study, with blinding of
both the participants and the outcome assessor. Surgeons were
not blinded. Exclusion criteria included (a) patients who did
not adhere to the post-NSV evaluation protocol as described
later, and (b) patients who did not give consent for the study.
Included patients were alternately allocated to one of the 2
groups, and sequentially numbered, opaque, sealed envelopes
were used for allocation concealment.
0090-4295/10/$34.00
doi:10.1016/j.urology.2010.01.091
341
Vasectomy Technique
Group A (control group) underwent NSV as described by Li et
al. along with segmental excision of vas and fascial interposition
between the suture ligated cut ends.3 Group B (intervention
group), in addition to NSV, underwent bilateral flushing of the
distal vas. This was accomplished on each side by gently pushing in 30 mL of sterile water via a 20-G intravenous cannula
inserted for a distance of about 1.5 cm through the open cut end
of the distal vas. Once flushing was completed, the distal vas
was ligated just beyond the cannula and the segment of distal
vas proximal to the ligature was excised. Vasectomy in both
groups was performed under local anesthesia by 3 experienced
surgeons (certified NSV trainers).
Semen Analysis. Evaluation protocol in the follow-up period
consisted of semen analysis at 4, 8, and 12 weeks after NSV,
irrespective of the findings of semen analysis. The participants
were asked to produce a semen sample in a private room at the
laboratory. Semen samples were examined within 1 hour of
collection. An aliquot was examined by phase-contrast microscopy at high-power magnification (400x) to estimate sperm
concentration. Based on the estimated concentration, dilutions
were prepared to assess exact sperm concentration and motility.
The concentration and motility of each sample were determined using a Neubauer hemocytometer. Samples with no
sperm (azoospermia) on the initial unspun semen analysis were
centrifuged for 15 minutes at 600 g and then reassessed for
sperm concentration and motility as described before.
Study Outcomes. The primary outcome measure was azoospermia (no detectable sperm on spun semen analysis), either as the
rate at postvasectomy follow-up visits or the time to azoospermia. Secondary outcomes included were the incidence of intermittent sperm reappearance in the ejaculate after a period of
azoospermia, number of ejaculations, operating time, and adverse events. Further, patients were instructed to record all
episodes of ejaculation post-NSV for a period of 12 weeks. The
2 groups were compared with regard to age, operative time,
number of ejaculations, frequency and type of complications,
and the proportion of patients azoospermic at 4, 8, and 12 weeks
after NSV. For the purpose of this study, all patients whose
semen sample was negative for sperm (azoospermia) at 4 and/or
8 weeks still underwent semen analysis at 12 weeks to see the
incidence of early intermittent reappearance of sperm.
Sample Size Estimation and Statistical Analysis Methods. An
a priori sample size calculation was done and our plan was to
enroll at least 300 participants in each group to get 80% power
to detect a difference between the groups, with a two-sided test
and an alpha of 0.05. Data analysis was done using SPSS
software (version 11.5, SPSS, Inc., Chicago, IL) and a twosided P value of ⬍0.05 was considered statistically significant.
Fisher’s exact test was used for comparisons of the dichotomous
(azoospermia) variables and Welch’s corrected t-test was used to
compare the means.
RESULTS
A total of 1566 men underwent NSV during the study
period. Of these, 906 patients gave consent for the study.
One-hundred seventy-nine (19.76%) of the 906 men
were subsequently excluded because of nonadherence to
the follow-up evaluation protocol, leaving 727 (80.24%)
342
Figure 1. Study participant disposition flow chart.
men (group A: 375 men; group B: 352 men) available for
final analysis (Fig. 1). Mean age, mean operative time,
and mean frequency and type of complications did not
differ significantly between the 2 groups. Complications
were hematoma, infection, chronic orchalgia, palpable
nodule (sperm granuloma), and dissatisfaction with surgery. None of the patients in both groups complained of
symptoms suggestive of “clinical” prostatitis, such as fever, dysuria, and voiding or storage lower urinary tract
symptoms. Two patients in group B and 1 patient in
group A complained of self-limiting painful ejaculation
between days 5 and 9; however, none had clinical hematospermia. A transient desire to urinate was described by
most patients in the irrigation group.
A significantly higher proportion of patients in group B
were azoospermic at 4 and 8 weeks when compared with
group A (group B: 53.40% and 80.68%; group A: 33.86%
and 49.6% at 4 and 8 weeks, respectively). The proportion of azoospermic patients at 12 weeks did not differ
significantly between the 2 groups. The mean number of
ejaculations at 4, 8, and 12 weeks did not differ significantly between the 2 groups (Table 1).
COMMENT
Although NSV is rapidly gaining in acceptance as a
contraceptive method, the delay in achieving “infertile
status” is a factor that affects the patient acceptability of
the procedure. Further, a major cause of vasectomy failure/unwanted pregnancy, especially in developing countries, is an ill-informed or negligent patient who assumes
that he is sterile shortly after the procedure. Any method
that would help in achieving rapid sperm clearance
would in part address the those issues.
UROLOGY 76 (2), 2010
Table 1. Comparison of variables and results of semen analysis between group A and B
Variable
Age (years)
Mean ⫾ SD
Median (range)
Operative time (min.)
Mean ⫾ SD
Median (range)
Azoospermic patients (%)
4 wks
8 wks
12 wks
Mean number of ejaculations ⫾ SD
4 wks
8 wks
12 wks
Group A (n ⫽ 375)
P Value
.41
32.4 ⫾ 5.68
31 (25-47)
32.09 ⫾ 4.51
31 (24-45)
8.76 ⫾ 2.13
8 (6-14)
9.03 ⫾ 1.92
9 (7-17)
127 (33.86)
186 (49.6)
352 (93.86)
188 (53.4)
284 (80.68)
341 (96.87)
⬍.0001
.0001
.08
11.48 ⫾ 2.98
20.48 ⫾ 3.85
32.78 ⫾ 5.5
11.75 ⫾ 2.62
20.7 ⫾ 3.69
33.55 ⫾ 5.47
.194
.43
.06
.07
Currently, there is little consensus about whether
flushing of the distal vas helps to achieve azoospermia
earlier. Sommer et al, in a study of 59 patients, used 40
mL of sterile water for vasal flushing and reported a
significantly shorter time to azoospermia.4 Roshani et al,
in a study of 126 patients, also reported significantly
higher azoospermic rates of 100% at 12 weeks and 88.1%
at 16 weeks in patients who underwent distal vasal flushing with 40 mL of sterile water and saline solution,
respectively, when compared with patients in whom vasal flushing was not used (26.2% azoospermic at 16
weeks).5 In contrast, studies by Mason et al (200 men
undergoing vasectomy with or without vasal lavage using
10 mL of sterile water) and Eisner et al (106 men undergoing vasectomy with or without vasal flush using 10 mL
of normal saline) failed to demonstrate any benefit of
distal vasal flushing insofar as hastening azoospermia was
concerned.2,6 Although it may be argued that these 2
studies may not have been able to demonstrate a significant difference in outcomes because the quantity of fluid
used to flush the vas was suboptimal in both (10 mL), a
nonrandomized, controlled study of 72 patients by Pearce
et al, in which 50 mL of normal saline was used for vasal
flushing, also did not demonstrate any benefit in terms of
hastening azoospermia.7 In addition, the possible explanation could be that all of these trials were poor quality
and relatively small and therefore underpowered. None
of the previously cited studies mentioned about the
method of semen analysis (spun vs unspun sample), except Mason et al, used a centrifuged semen sample for
postvasectomy semen analysis.
Another reason for discrepancies between the results
of various studies may be that these studies did not take
into account the number of ejaculations during the follow-up period, because time to infertility also depends on
the frequency of postoperative ejaculations.4 The number
of ejaculations after NSV is also important in addition to
the time period to achieve azoospermia; approximately
80% of patients are azoospermic after 3 months and after
about 20 ejaculations.8 In our study, the mean number of
UROLOGY 76 (2), 2010
Group B (n ⫽ 352)
ejaculations between the 2 groups did not differ significantly at any point in the follow-up and hence it seems
reasonable to presume that it was the vasal flushing that
resulted in a significantly higher percentage (between
20% and 30%) of patients being azoospermic at 4 and 8
weeks postvasectomy.
Another area of controversy is when to label a man
infertile after NSV. There is no absolute standard of care
when it comes to declaring a patient sterile. Follow-up
semen analysis at least 2-3 months after vasectomy, with
the goal of obtaining at least 1, and preferably 2, absolutely azoospermic specimens 4-6 weeks apart, is recommended.8-11 Because intermittent reappearance of sperm
usually occurs early after vasectomy, for the purpose of
this study, patients whose semen sample was negative for
sperm at 12 weeks were finally considered infertile. For
those who achieved azoospermia earlier, subsequent samples as per protocol were still taken to ensure that the
patient’s semen remained sperm-negative. The study end
point was taken as completion of 12 weeks’ follow-up
after NSV regardless of azoospermic status. Three patients in group A and 2 patients in group B whose semen
sample was negative for sperm at 4 weeks had reappearance of sperm during semen analysis at 8 weeks. Semen
analysis at 12 weeks showed that all 5 patients again
became azoospermic, so they were considered infertile,
the timing of infertility being taken as 12 weeks in all 5.
One patient in group A who had a semen sample negative for sperm at 8 weeks showed sperm in his semen
sample at 12 weeks and was considered not to have
become infertile as per study protocol. Thus, reappearance of sperm was seen in 6 patients during the whole
follow-up period of 12 weeks. It is controversial whether
this early intermittent reappearance of motile sperm in
semen is the result of transient early recanalization or
residual sperm in the distal vas. Regarding vas irrigation,
some experts believe that the presence of motile sperm in
semen after 4-6 weeks is more likely to be the result of
transient early recanalization rather than residual sperm
in the distal vas.12 The chances of recanalization are less
343
when fascial interposition is used along with excision and
ligation of vas, because an international multicenter trial
of vasectomy with and without fascial interposition demonstrated a 2-fold reduction in failure rates using fascial
interposition.13 Although uncommon, the late failure
rate has been reported to be 0.04%-0.08%, and recanalization is usually only discovered after pregnancy in the
female partner.14 However, so far we have not received
report of any pregnancy.
The findings of azoospermia differ in the whole semen
(unspun) versus the spun specimen. The laboratory should
examine a freshly produced seminal fluid specimen by
direct microscopy and if no sperm are seen, the centrifuged sample should be examined for the presence of
motile and nonmotile spermatozoa.15 Semen centrifugation should be performed in all men considered to have
azoospermia by routine semen analysis because studies
have demonstrated the presence of motile and nonmotile
sperm in a significant number of men considered to have
azoospermia by routine semen analysis.16
Our study shows that distal vasal flushing with sterile
water does shorten the time to azoospermia in a statistically significant number (between 20% and 30%) of
patients at 4 and 8 weeks after NSV. For developing
countries, it may also be important from an economic
point of view, to reduce the 1-month cost of barrier
methods because semen analysis at 8 weeks was negative
for sperm in more than 80% of cases of vasal flushing.
Vasal flushing may also reduce, to some extent, the
chances of unwanted pregnancies in uneducated, poor,
and neglected communities of developing countries in
addition to increasing the acceptance rate for vasectomy.
Although no formal survey was conducted regarding
whether the difference of 4 weeks had any importance to
these patients in choosing vasectomy, the clients often
raised concerns about the long duration of postvasectomy
condom usage. After this study, our current “clinical”
protocol for post-NSV semen analysis is a single semen
analysis at 8 weeks. If the patient is sterile (azoospermic
on spun semen analysis) at 8 weeks, we do not pursue
further semen analysis in these patients and an additional
semen analysis is done monthly until azoospermia is
achieved or up to 6 months in patients who had sperm in
their semen samples at 8 weeks.
To our knowledge, this is the largest reported randomized,
controlled trial addressing the issue of the effect of distal vasal
flushing on the time taken to achieve azoospermia. Limitation
of our study is lack of long-term follow-up and a high rate of
exclusion (19.76%) after randomization because of nonadherence to the follow-up evaluation protocol. Loss to follow-up
rates greater than 20% may threaten the validity of trials.17
Patient compliance decreases significantly with each subsequent visit for post-NSV semen analysis,10 thus, in our opinion
the overall compliance rate of more than 80% in the present
study is not unacceptably high. Although extremely rare, there
is some theoretical risk that the catheter itself might create risk
of recanalization by damaging the vas. Another theoretical
344
concern is the risk of seminal vesiculitis, prostatitis, and inflammation inside the lumen of the distal vas, which may compromise the luminal patency of the abdominal vas during future
vasectomy reversal. Finally, because these results are based on 1
large trial, the evidence would be stronger if confirmed by a
second trial.
CONCLUSIONS
Distal vasal flushing with 30 mL of sterile water may shorten
the time to azoospermia to between 20% and 30% of vasectomy patients. Thus, this procedure may be an option for
some who choose the vasal flush to avoid the long duration
of postvasectomy alternate contraceptive methods.
References
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