There is a very nice review on the "safety and effectiveness of vasectomy" in
the May 2000 73(5) issue of Fertility and Sterility. Schwingl and Guess review
the major variations and complications of vasectomy.

"Surgical methods also vary by method of vas occlusion and length of vas removed
[10 and 13]. Several surgical techniques for occluding the vas have been
developed with the goals of avoiding recanalization of the vas, enhancing
potential for reversal or avoiding side effects associated with increased
pressure on the testicular end of the ligated vas. Vas occlusion differs by the
method of ligation (nonabsorbable suture, cautery, clips, or some combination)
and by whether the testicular side of the vas is left unsealed (open-ended
vasectomy, which is rarely used) or sealed (closed-ended vasectomy, which is
more commonly used) [10 and 13]. Any of these methods may be used with
interposition of the fascia between the cut ends." Basically, if y

"Although most sperm granulomas are small and asymptomatic, painful sperm
granulomas may occur in 2%–3% of vasectomies, typically in the second or third
postoperative week [15 and 40]."

"Congestive epididymitis presents as pain and testicular tenderness on the
affected side. Generally, the occurrence of epididymitis is uncommon and is
reported in 0.4%–6.1% of vasectomies [53 and 54]. Congestive epididymitis can
occur sooner or later after vasectomy and linger. Typically, it lasts weeks to
months, and it is extremely rare for it to last >1 year. It is usually treated
with analgesics and antibiotics."

"Congestive epididymitis has been attributed to pressure within the epididymis
from sperm production in the presence of an occluded outlet...In one large
series, the frequency of congestive epididymitis with closed-ended vasectomy was
reported to be higher than with open-ended vasectomy (6% vs. 2%; relative risk =
3.0 (95% confidence interval [CI] = 1.2–7.5) [50]. Even among closed-end
vasectomy the incidence varies by method of occlusion...[55]."

"Among the reported long-term complications of vasectomy is a syndrome of
chronic noninfectious epididymal pain and induration beginning months to years
after vasectomy [56]. This syndrome has been attributed to long-standing
obstruction with dilatation of the epididymal ducts, extravasation of sperm and
sperm granulomas with an inflammatory reaction. The syndrome appears to be quite
rare, and the attribution to vasectomy is based on case reports."