AJCP / Original Article
Rethinking the Value of Sending Vasectomy Specimens
for Histologic Examination
An Analysis of Arterial Vasculature and Failure to Transect
the Vas Deferens
CME/SAM
Abhishek P. Patel, MD,1 Gregory J. Lowe, MD,1 and Debra L. Zynger, MD2
From the Departments of 1Urology and 2Pathology, The Ohio State University Medical Center; Columbus, OH.
Key Words: Vasectomy; Vas deferens; Testicular artery; Histologic examination; Vasectomy complications
DOI: 10.1309/AJCPAPHJEG2J5MIF
ABSTRACT
Objectives: The testicular, deferential, and cremasteric
arteries and their branches surround the vas deferens
(VD), leaving them susceptible to injury during vasectomy.
Literature describing the caliber of arteries seen in
vasectomy specimens is lacking, making it difficult to
categorize the significance of an observed artery. We aimed
to establish reference values for arterial size typically
encountered in vasectomy specimens and assess our
institutional experience with failure to transect the VD.
Methods: The luminal diameter of the largest artery in
231 consecutive VD specimens from 116 patients was
measured microscopically. For comparison, the diameter
of the largest artery within 10 spermatic cord cross-sections
from inguinal orchiectomies was obtained. The immediate
vasectomy failure rate based on histologic assessment was
calculated using specimens from 2008 to 2012.
Results: The luminal diameter of the largest artery
encountered in a vasectomy specimen was 1.00 mm or less
in 96.5% of cases. Artery sizes greater than or equal to 2.50
mm were only seen in spermatic cord resections. From 2008
to 2012, three (0.36%) of 837 patients undergoing vasectomy
had specimens that showed failure to transect both VD.
Conclusions: Although the American Urologic Association
and European Association of Urology state that histologic
evaluation of vasectomy specimens is not required, we
encourage the surgeon to send VD specimens for histologic
examination. Doing so allows early identification of the
failure to transect the VD and the resection of surrounding
vasculature, providing quality control feedback to the surgeon.
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Upon completion of this activity you will be able to:
• list postvasectomy complications.
• describe methods for verification of sterility postvasectomy.
• discuss the benefits of histologic analysis of vasectomy specimens.
The ASCP is accredited by the Accreditation Council for Continuing
Medical Education to provide continuing medical education for physicians.
The ASCP designates this journal-based CME activity for a maximum of
1 AMA PRA Category 1 Credit ™ per article. Physicians should claim only
the credit commensurate with the extent of their participation in the activity. This activity qualifies as an American Board of Pathology Maintenance
of Certification Part II Self-Assessment Module.
The authors of this article and the planning committee members and staff
have no relevant financial relationships with commercial interests to disclose.
Questions appear on p 444. Exam is located at www.ascp.org/ajcpcme.
Vasectomy is a common surgical procedure performed
worldwide for permanent male sterilization. In the United
States, more than 500,000 men undergo this procedure annually,1 and it is the most common nondiagnostic operation
performed by urologists.2 According to the National Survey
of Family Growth, 13.1% of married men surveyed from 2006
to 2008 reported having a vasectomy.3 Various techniques are
used to carry out this procedure, from a no-scalpel approach
in the office to a small open incision in the operating room.
Regardless of the method, a key step involves identifying and
transecting the vas deferens (VD). Complications are uncommon, and those that do occur are mostly minor, such as hematoma, infection, sperm granuloma, and chronic orchalgia.4
Isolated instances have been reported of complications
with significant morbidity, including Fournier gangrene,5-7
subtotal testicular infarction,8 and testicular necrosis.9 Blood
is supplied to the testicle via the cremasteric, testicular, and
deferential arteries.10 These arteries and their branches lie
within close proximity to the VD in the spermatic cord,
© American Society for Clinical Pathology
AJCP / Original Article
making them susceptible to damage during a vasectomy. One
of these rare complications is illustrated by a case for which
we were consulted, wherein a patient underwent an office
vasectomy ❚Image 1❚. Histologic examination of the rightsided specimen showed a 1.5-mm artery but no VD. A repeat
right vasectomy did show the presence of VD, along with a
large 3.30-mm artery. Unfortunately, this patient subsequently
developed right-sided ischemic testicular necrosis treated with
a delayed right orchiectomy.
There is a lack of literature describing the caliber of
arteries histologically present in vasectomy specimens,
and thus the significance of an observed artery is currently
unknown. We measured the diameter of the largest artery
seen within vasectomy specimens and compared it with
those seen in cross-sections of the spermatic cord from
orchiectomy specimens. We thus aimed to establish reference arterial diameter values for arteries encountered in
A
C
© American Society for Clinical Pathology
vasectomy specimens and assess our institutional experience
in failing to transect the VD.
Materials and Methods
For the study, 231 consecutively submitted VD specimens to The Ohio State University Department of Pathology
(Columbus, OH) from July 2011 to January 2012 were identified. All specimens were submitted in entirety, formalin-fixed,
paraffin-embedded, cut at 5 mm, and stained with H&E. All
specimens were initially reviewed by a subspecialty genitourinary pathologist and were retrospectively reviewed by one
urology resident (A.P.P.) who was trained by a genitourinary
pathologist (D.L.Z.). Institutional review board approval was
obtained. The investigators were blinded to both surgeon and
patient information.
B
❚Image 1❚ Histologic specimens from a case received in
consultation. A, Right vasectomy specimen (×10). Arrow
shows a 1.5-mm muscular artery. There is no vas deferens
(VD) in the specimen. B, Repeat right vasectomy specimen
(×2). Arrow shows a large 3.3-mm muscular artery. Arrowhead
shows VD. C, Orchiectomy specimen with necrotic testicular
parenchyma (×20).
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Charts were reviewed to obtain the patient’s age, name
of surgeon, and the length and diameter of each VD specimen. All histologic sections were inspected using an Olympus
microscope (Olympus America, Center Valley, PA). Veins
and arteries were differentiated by examining their diameter
along with the number of smooth muscle cell layers in the
tunica media, with veins having only two to three smooth
muscle layers and a typical small artery having eight to
ten layers. The largest artery was identified and its luminal
diameter was microscopically measured. The VD was identified by its pseudostratified apical columnar epithelium with
stereocilia and cuboidal basal cells overlying loose connective tissue stroma and a well-developed, thick, three-layered
muscular coat.11 For specimens with extreme oblique cuts, the
specimen was reviewed by the genitourinary pathologist, and
a joint decision of the luminal diameter was made.
Ten inguinal orchiectomy specimens submitted with
intact spermatic cords from July 2011 to August 2012 were
randomly chosen. All of these specimens were from radical
inguinal orchiectomies performed for suspicion of testicular
cancer. These spermatic cord cross-sections should include
all vasculature surrounding the VD that the surgeon could
theoretically injure during a vasectomy. For each specimen,
the midpoint of the spermatic cord was analyzed, and the
diameter of the largest artery within these cross-sections was
measured with the same microscope.
Statistics were performed using StatPlus 2009 (AnalystSoft, Vancouver, Canada). Normality was assessed with the
Shapiro-Wilk W test. One-way analysis of variance with Bonferroni test was used to test for differences between the means
of the spermatic cord and vasectomy specimens and between
the means of the VD specimens amongst pairs of surgeons.
Significance was defined as P < .05.
In addition, to assess the immediate surgical failure rate,
all vasectomy specimens submitted during the 5-year period
from January 2008 to December 2012 were identified. For
each specimen, the histologic presence or absence of VD
was noted. Charts of patients with an absence of VD and
those with arterial sizes in the third and fourth quartiles were
reviewed to determine the clinical outcome.
Results
Nine surgeons submitted 231 VD specimens from 116
patients (one patient only had one VD). Four surgeons submitted the majority of specimens (94.8%). The median age
of vasectomy patients was 37 years (range, 21-56 years). The
median length and diameter of VD were 1.0 cm (range, 0.43.4 cm) and 0.3 cm (range, 0.3-0.5 cm), respectively.
The mean diameter of the largest artery in the VD specimen was 0.03 mm, with the median being 0.03 mm, and the
range was 0.01 to 1.70 mm. The percentage of specimens
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with luminal diameter of the largest artery in the following
quartiles was as follows: 0.01-0.42 mm, 71.0%; 0.43-0.85
mm, 23.4%; 0.86-1.19 mm, 2.2%; 1.20 mm or more, 3.5%
(mean, 0.03 mm; median, 0.03 mm; range, 0.01-1.70 mm)
❚Image 2❚ and ❚Figure 1❚. Chart review failed to reveal any
intra- or postprocedural complications for patients in the third
and fourth quartiles (n = 13).
For the 10 spermatic cord specimens obtained via an
orchiectomy, the median patient age was 35 years (range,
21-55 years). The luminal diameter of the largest artery
ranged from 2.50 to 4.10 mm, with a median of 3.40 mm.
The midpoint of the spermatic cord ranged from 3.35 to 7.55
cm, with a median of 4.75 cm away from the testicular hilum.
The Shapiro-Wilk W test failed to show normality
among the VD specimens but did show normality among the
spermatic cord specimens. The difference in the mean arterial sizes seen in the vasectomy specimens vs the spermatic
cord specimens was statistically significant (P = 0) ❚Table
1❚. The difference between the mean arterial size seen in VD
specimens for surgeon 3 and surgeon 4 was also statistically
significant (P = .02) ❚Table 2❚.
During the 5-year period from 2008 to 2012, histologic examination in three of 837 patients (1,674 vasectomy
specimens) failed to reveal transection of both VD (rate of
vasectomy failure, 0.36%). For the first patient, the surgeon
suspected missing the VD during the office procedure after
spending longer than the usual amount of time searching for
the VD and only finding atretic-appearing tissue. Histologic
examination showed vascular channels but no VD ❚Image 3A❚,
and the patient underwent repeat vasectomy in the operating
room under general anesthesia with a larger incision. The
repeat histologic examination verified the presence of VD in
the specimen. The second patient was morbidly obese, and the
surgeon was uncomfortable performing the procedure in the
office because of concern regarding the inability to isolate the
VD. This patient underwent a vasectomy in the operating room,
and the surgeon noted difficulty in isolating the VD. Histologic
examination showed only skeletal muscle fibers ❚Image 3B❚.
After learning of the one-sided vasectomy failure, the patient
elected not to proceed with repeat vasectomy and underwent
a postvasectomy semen analysis (PVSA) after 10 weeks.
Motile sperm were found, the patient then elected to undergo
repeat vasectomy, and the surgeon intraoperatively confirmed
the transection of VD with a frozen section. The third patient
underwent an office vasectomy, and histologic examination
showed scant blood vessels without VD ❚Image 3C❚. The
patient did not keep his follow-up appointment. For unknown
reasons, he underwent PVSA 1 year after the vasectomy, which
showed presence of motile sperm. The surgeon was able to
contact the patient via telephone, but the patient did not follow
up for completion vasectomy. Of note, resident physician participation was limited to the procedure for the second patient.
© American Society for Clinical Pathology
AJCP / Original Article
A
C
B
❚Image 2❚ Examples of surrounding vasculature in histologic
specimens. A, Vasectomy specimen with minimal vessels
(“bare vas”; ×4). B, Vasectomy specimen with a 0.7-mm
artery (circled) (×4). C, Spermatic cord from an orchiectomy
specimen with a 3.0-mm artery (×2).
© American Society for Clinical Pathology
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Vasectomy is one of the most common procedures
performed worldwide for permanent male sterilization. Measurement of success is clinically important and is ultimately
established by azoospermia in PVSA.2 A histologic examination report generally comments only on either the presence or
absence of VD; no data are available to assess the nature of
perivasal vasculature. We conducted our study to examine the
caliber of arterial vasculature typically seen in vasectomy specimens and to evaluate our immediate vasectomy failure rate.
At our institution, the arterial size routinely encountered
in a VD specimen was 1.0 mm or less in 96.5% of cases,
and the largest artery was 1.7 mm. Artery sizes of 2.5 mm or
more were only seen in spermatic cord resections. We demonstrated statistically significant intersurgeon variability in the
mean arterial diameter in the VD specimens, likely a result
of differences in surgical technique. Although no previous
work has reported arterial sizes in VD specimens, Raman and
Goldstein12 intraoperatively measured the diameter of each
Percent of Vasectomy Specimens
40
Discussion
Diameter of Largest Artery (mm)
❚Figure 1❚ Diameter of the largest artery seen in vasectomy
specimens. Arterial size routinely encountered in a vas
deferens specimen was 1.00 mm or less in 96.5% of cases,
and the largest artery was 1.70 mm.
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❚Table 1❚
Comparison of the Diameter of the Largest Artery in Vasectomy vs Spermatic Cord Specimens
Diameter of the Largest Artery, mm
Minimum
MaximumMean
SD
P
Vasectomy specimens (n = 231)
Spermatic cord specimens (n = 10)
0.001
2.5
0.17
4.1
0.03
0.6
0
0.03
3.4
SD, standard deviation.
❚Table 2❚
Intersurgeon Comparison of the Mean Diameters of the
Largest Arteries in Vas Deferens Specimens
Surgeon vs Surgeon
P
1 vs 2
1 vs 4
2 vs 4
1 vs 3
2 vs 3
3 vs 4
1
1
1
.29
.08
.02
artery in the spermatic cord at the external inguinal ring during 120 microsurgical subinguinal varicocelectomies. They
found that the testicular artery diameter ranged from 0.2 to
1.9 mm (mean, 1.0 mm), deferential artery diameter ranged
from 0.2 to 1.8 mm (mean, 0.6 mm), and cremasteric artery
ranged from 0.1 to 1.5 mm (mean, 0.5 mm). Yalcin et al13
measured arterial diameter in cadaveric orchiectomy specimens and found the mean diameters of testicular, deferential,
and cremasteric arteries to be 1.7 mm, 1.1 mm, and 0.5 mm,
A
B
C
❚Image 3❚ Vasectomy specimens without the presence of the
vas deferens. The specimens show (A) vascular channels
(×2), (B) skeletal muscle fibers (×4), and (C) small blood
vessels (×10).
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© American Society for Clinical Pathology
AJCP / Original Article
respectively. In both of these investigations, arterial diameter
was measured using a microruler of a nontransected artery. In
contrast, our data are more clinically applicable because the
arterial luminal diameters in the vasectomy specimens were
measured after routine histologic fixation.
Studies have shown that the primary branch point for the
testicular artery occurs during its course through the inguinal
canal,10,14,15 indicating that the largest-caliber artery found at
the level of the midspermatic cord (median of 4.75 cm away
from the testicular hilum in our study) most likely represents
not the main artery but one of its branches. Because the testicular artery branches proximal to the region of the spermatic
cord encountered during vasectomy and given the trimodal
blood supply to the testicle, even if a large-caliber artery is
transected during a vasectomy, redundancy of arterial flow
to the testicle likely ensures parenchymal survival. However,
if the testicular vasculature suffers repeated insult, testicular
ischemic necrosis is possible, as illustrated by our aforementioned case and other case reports.8,9
The usual reason for histologic analysis of VD specimens
is to confirm the presence of VD. However, both the American Urological Association and the European Association of
Urology state that histologic assessment of vasectomy specimens is no longer required and leave it to the discretion of
the surgeon to send the excised tissues for histology.2,16 This
recommendation is based on expert opinion. Surgeons worldwide do send the specimens for histologic review. No large
studies have been conducted on the percentage of surgeons,
but in a small survey of surgeons in England, 63 (75%) of 84
sent the vas routinely for histology.17 In addition to our anecdotal experience with academic centers in the United States,
reports from France, Finland, England, and New Zealand
have described surgeons and institutions routinely sending
vasectomy specimens for analysis (the rationale varies from
legal support to historical practice to early identification of
failure to transect the vas).18,19 The most recent American
Urologic Association vasectomy guideline recommends isolating the VD from perivasal tissue and only transecting a
“bare vas.”2 At times, more perivasal tissue may intentionally
be taken to speed up the procedure or because the assistant
happens to take a larger cut. Although the urologist is able to
roughly gauge the likelihood of transection of a significant
artery at the time of the procedure, histologic analysis can
augment what the urologist sees and provide an additional
assessment of technical adequacy and quality control feedback. Another practical application of the histologic analysis
is the surgeon’s ability to recognize the risk of testicular
infarction with subsequent procedures that may injure the
testicular artery, such as a hernia repair, varicocelectomy,
nephrectomy, or aortic aneurysm repair. We do not advocate
measuring perivasal vessels in every case or mentioning this
in the pathology report. However, a good guideline is that if
© American Society for Clinical Pathology
the vessel is similar in size or larger than the vas, it may be
worth mentioning because it may be clinically relevant in preventing future complications and providing the surgeon with
quality control feedback.
Previous articles have reported vasectomy failures, but
ours is the only study detailing immediate surgical failure to
transect VD defined by histologic analysis.4,20,21 In addition,
to our knowledge, this is the first report of the use of a frozen
section for VD confirmation. Assuming our surgical skill and
patient level of complexity applies to the estimated 500,000
vasectomies performed annually in the United States, a failure
rate of 0.36% leaves 1,800 postvasectomy patients still fertile.
Without submitting the VD specimen for histologic analysis,
the surgeon has to wait until the patient provides a PVSA to
learn of the vasectomy failure. However, multiple publications
have shown a trend of poor patient compliance, with 30% to
45% of patients never returning to provide a PVSA, even with
proper follow-up instructions.22-25 As such, of these 1,800
patients, a 30% noncompliance with PVSA leaves 540 patients
annually with an unrecognized risk of pregnancy. A subsequent
unplanned pregnancy can lead to emotional, social, and financial strains on the patient and partner(s), leading to the high rate
of “wrongful conception” litigation in this population.
We used the 2013 United States Medicare allowable billing for the Current Procedural Terminology (CPT) code to
determine the cost of a vasectomy. The charge for office-based
vasectomy by the surgeon, including the PVSA, is $1,320
(CPT code: 55250). The billing for surgical pathology examination for one VD removed for sterilization is $44.59 (CPT
code: 88304) and two separately submitted VD is $89.18 (two
units of CPT code: 88304). Histologic examination therefore
increases the total cost of a vasectomy by 6.8%. Given the
litigious aspect of the vasectomy procedure26 and the poor
PSVA compliance rate, surgeons should strongly consider this
cost-effective method of having histologic confirmation of a
transected VD. Histologic analysis is also useful for persistent
sperm in a PVSA. Histologic examination cannot differentiate
the laterality of the specimen and is solely dependent on the
labeling at the time of specimen acquisition. However, histologic proof that two VD specimens were transected provides
encouragement to the surgeon to conduct another PVSA rather
than subject the patient to a repeat procedure. On the other
hand, failure to histologically identify a transected VD is a critical result in which the pathologist should immediately contact
the surgeon, facilitating rapid communication from the surgeon
to the patient for scheduling a repeat procedure.
This investigation does have limitations. A perfect perpendicular histologic cross-section was rare, and as such, small
measurement errors may have been introduced in estimating
the luminal diameter of these oblique cross-sections. Only one
researcher examined the specimens, which were processed
at a single institution; hence, there is a need for confirmation
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by additional investigators at other locations. Because all our
specimens were fixed with formalin, the measurements in our
study will not be applicable to in vivo measurements of intact
nonfixed tissue. The exact location of VD transection during
a vasectomy was not known, limiting the comparison with
spermatic cord specimens, whose exact point of fixation along
the spermatic cord was known. In addition, three of the four
surgeons performing the majority of procedures routinely had
resident physicians assisting, thus limiting the comparability
among surgeons. However, the lack of normal distribution
in the diameter of the largest artery for all VD specimens is
consistent with differences in surgical technique affecting the
size. Moreover, the presence of a normal distribution in the
spermatic cord specimens is reassuring because the surgical
technique used to obtain these specimens is similar.
In conclusion, we found that arterial size routinely encountered in histologic examination of vasectomy specimens was
1.0 mm or less in 96.5% of cases. Artery sizes greater than
2.5 mm were only seen in spermatic cord resections. Surgical failure to transect the vas is rare but does occur (0.36% of
cases). Although the expert opinion statement of the American
Urologic Association and the European Association of Urology
states that histologic confirmation of vasectomy specimens is
not required, we recommend that the VD specimen be sent for
histologic examination. Doing so allows rapid identification of
failure to transect the VD; provides risk assessment for future
inguinal, scrotal, or retroperitoneal surgeries that may compromise the testicular artery; and encourages the surgeon to
repeat a PVSA in case of persistent sperm on semen analysis.
Histologic confirmation of VD transection may be a valuable
asset at the time of litigation for wrongful conception, and
identification of transection of the surrounding vasculature also
provides feedback to improve surgical quality and patient care.
Address reprint requests to Dr Zynger: Dept of Pathology, The
Ohio State University, 410 W 10th Ave, 401 Doan Hall, Columbus,
OH 43210; [email protected].
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© American Society for Clinical Pathology