Revision Actualizada 2009 Sobre Vasectomia

Overview of vasectomy Authors Theodore J Ongaro, MD Christopher J Cutie, MD Section Editor Michael P O'Leary, MD, MPH Deputy Editor Kathryn A Collins, MD, PhD Last literature review version 17.1: January 2009 | This topic last updated: January 31, 2008 (More) INTRODUCTION — Vasectomy is the most effective available mode of male contraception. The procedure involves interruption or occlusion of the vas deferens, and is typically performed in an outpatient setting under local anesthesia. Worldwide, in 2004 almost 43 million men had undergone vasectomy [1] . Slightly more than one half million vasectomies were performed in the United States (US) in 2002 [2] . Approximately 79 percent of vasectomies in the US were performed by urologists, 13 percent by family practitioners, and 8 percent by general surgeons. Procedure costs range from $350 to $1,000, far below costs associated with longterm pharmacologic contraception or female sterilization procedures. The most common sterilization procedure for women, tubal ligation, requires entering the peritoneal cavity to access the fallopian tubes, and is usually performed under general anesthesia. Compared to tubal ligation, vasectomy is safer, less costly, and has a significantly shorter post-procedure recovery time. Nonetheless, worldwide, tubal ligation is performed five times more often than vasectomy [3] . This suggests lower acceptance of vasectomy, which may be attributed to a variety of reasons, including misperceptions of the procedure and its side effects. Reported rates of successful infertility for vasectomy exceed 98 percent [4,5] , though data are limited by lack of longterm follow-up. Most studies report outcomes only within two years of the procedure, and might not account for subsequent failures due to later recanalization. This topic will present an overview of vasectomy, and will discuss patient selection, types of procedures, and surgical outcomes. A generalized discussion of contraception is presented separately. (See "Overview of contraception"). PATIENT COUNSELING — A thorough preoperative discussion is important, as is true for any surgical procedure, and should review the risks, complications, and longterm effects associated with vasectomy. The formal preoperative discussion should take place with the surgeon, but the referring clinician should discuss the procedure with the patient prior to arranging the referral. This initial discussion should provide information about the nature of the procedure and alternative contraceptive options, and address patient expectations and questions. The discussion between patient and referring clinician should review: Contraception

method(s) used, and patient understanding of alternatives Patient understanding that the procedure results in permanent sterility Social/family status: whether in stable relationship, number and ages of children (if any), acceptance of procedure by partner, future family intent Overview of procedure and recovery time Patient understanding of the need for interim contraception for a minimum of three months, and semen analysis prior to assuming sterility Need for ongoing use of condoms to protect against sexually transmitted infections if not in a committed monogamous relationship Reversibility of procedure — Vasectomy, while reversible in some cases, may be permanent. Successful vasectomy reversal has been reported in fifty to seventy percent of men [6,7] . Rates decline with increasing time between vasectomy and reversal [8] . Patients must be adequately counseled, and vasectomy should be undertaken only in men who intend to have permanent sterility. Multiple studies have examined the relationship between patient characteristics and the likelihood of a future request for vasectomy reversal. The strongest predictive factor for a future vasectomy reversal request is a change in marital status [6] . Men without children, and men who were older than 30 years at the time of vasectomy, were less likely to request a reversal in the future [9] . There was no correlation between a patient's religion, number of marriages, or occupation, and the probability of a future request for reversal. OVERVIEW OF PROCEDURE — Vasectomy is typically performed under local anesthesia in the physician's clinic or in an outpatient surgical center. Some physicians administer an oral sedative, such as diazepam, one hour prior to the procedure for patient relaxation. Typically, men are able to go home one hour after the procedure. Although there are multiple variations in procedural technique, the two basic components of vasectomy are isolating the vas deferens from the scrotum and occluding the vas (show figure 1). Vasectomy approaches Conventional — The traditional vasectomy approach involves bilateral small (1 cm) scrotal incisions to visualize and mobilize the vas deferens. A portion of the vas is removed and the resulting end or ends are occluded by suture ligation, electrocautery fulguration or some combination thereof. The scrotal incision may be closed or left to heal by secondary intention. This technique now accounts for only a small proportion of vasectomies performed in the US (18 percent in 1995) but remains the most common technique used in many Asian countries, and in resource-poor areas of the world [10] . No-scalpel — More recently, a no-scalpel technique has been introduced that results in lower bleeding and infection rates [11] . In a randomized trial involving 1429 men in eight countries, patients undergoing no-scalpel vasectomy had shorter operating times, and less pain than with conventional techniques; sterility outcomes were the same for both procedures [12] .

To perform the no-scalpel procedure, a ring-tipped clamp is used to isolate and grasp the vas through the scrotal skin. The scrotal skin (at the site of previous anesthetic administration) is then punctured using a sharp mosquito hemostat. The vas is freed of its attachments, delivered through the small scrotal perforation and cut. The end or ends are then occluded. No skin closure is necessary, as the scrotal puncture site is virtually invisible [13] . Percutaneous — The percutaneous technique involves injecting two dyes into the vas, using a different color for the left and right vas. A sclerosing agent is then injected into the vas lumen and successful occlusion is determined by having the patient void to see which, if any, dye is excreted. The chemicals required for this procedure are not approved for use in the US. Vasal occlusion techniques — In both the conventional and no-scalpel techniques, the vasa are transected, a small section is removed, and one or both ends are secured. Different techniques have been explored to minimize the potential for recanalization of the vas, which could result in fertility. Suture ligation of the cut end of the vas is most common, and results in fibrosis and scarring of the cut vasal ends. Sloughing of the vas at the ligation site on both ends may result in recanalization. Failure rates with this occlusion technique range from 1 to 5 percent [14] . A systematic review found no difference in failure rates comparing suture ligation and use of hemoclips [15] . Rates of recanalization are somewhat lower (less than 1 percent) with electrocautery fulguration [16] . Some surgeons cauterize only the prostatic end of the vas, leaving the testicular end open (an open ended vasectomy). Fascial interposition, the placement of fascia over one cut end of the vas, is the most effective means of vasal occlusion when combined with either suture of fulguration. A randomized controlled trial, involving eight clinics in seven countries and 841 men, found that adding fascial interposition to ligation and excision reduced vasectomy failure rates from 12.7 to 5.9 percent [17] . Vasectomy failure was defined as >5 million sperm/mL at 14 weeks, or >100,000 sperm/ml with any motility at 26 weeks. The combination of cautery plus fascial interposition may be more effective than ligation plus fascial interposition [10] . Postoperative care — Post-procedure care of the vasectomy patient is important. Some scrotal swelling and bruising is common and will generally resolve spontaneously. Scrotal support with a fluff dressing and tight-fitting underwear or supporter is recommended for at least 48 hours after surgery. An ice pack intermittently applied to the scrotum for 48 hours helps decrease discomfort and swelling. Postoperative wound infection is rare following the no-scalpel technique, and prophylactic antibiotics are not necessary [18] . Patients should avoid taking preoperative aspirin and non-steroidal anti-inflammatory medications, as these may increase the risk of postoperative bleeding. Blood in the ejaculate is common and will typically clear after three to four days.

Bedrest or quiet activity is recommended for the first 24 hours following a vasectomy. Patients may return to light work in two to three days, but should refrain from heavy work, sports or lifting for one week. Sexual intercourse may be resumed after one week, but contraception must be used until azoospermia or sterility is confirmed. (See "Follow-up to confirm sterility" below). Follow-up to confirm sterility — A systematic review found that approximately 80 percent of patients are azoospermic after three months and 20 ejaculations [19] . The time to achieve azoospermia declines with increasing patient age, and increasing number of ejaculations after vasectomy. A semen analysis should be collected three or four months following vasectomy, and the patient should have had at least 20 ejaculates since the time of vasectomy [20,21] . The laboratory performing the analysis should examine a fresh specimen using direct microscopy; if sperm are not seen on the initial prepared slide, a centrifuged specimen should be evaluated. Traditionally, surgeons recommend obtaining two semen samples, ideally collected within four to six weeks of each other. If both specimens demonstrate no identifiable sperm, sterility is confirmed [14] . A review of eleven studies in which a sample was collected at three months post vasectomy found that 81 percent of men had achieved azoospermia [19] . This review recommends that one sample demonstrating azoospermia at three months is sufficient to determine sterility [19] . Azoospermia is the ideal end point of vasectomy. A small proportion of patients, however, do not achieve azoospermia but consistently have nonmotile sperm. The accuracy of determining whether sperm have normal motility is dependent on the specimen being delivered soon after ejaculation, and the semen examination taking place in a timely fashion. Recommendations from the British Andrology Society advise that patients may be considered infertile if they have a low sperm count (<10,000/mL), all sperm are immotile, seven months have elapsed from vasectomy and there have been a minimum of 24 ejaculations [20] . If motile sperm are confirmed on two samples one month apart, after a sufficient number of ejaculations (>20) and following an appropriate duration of time (>three months post procedure), it is likely the vasectomy has failed. The patient should be advised to have a second procedure and use alternative contraception. Failure — Failed vasectomy can be due to inadequate occlusion of the vas at the time of vasectomy, unprotected intercourse before the reservoir of viable sperm is depleted and azoospermia is documented, or recanalization. Late recanalization is rare, occurring in about 0.2 percent of patients [3] . COMPLICATIONS — The most important determinant of postoperative complications is operator experience. Surgeons performing more than 50 vasectomies had one-third the complication rate of those performing fewer than 10 procedures [22] .

Hematoma — Bleeding and/or hematoma formation is the most common complication associated with vasectomy. In rare cases, bleeding may be severe enough to require reoperation for scrotal exploration, hematoma evacuation, and control of bleeding. Hematoma rates are lower for no scalpel procedures, where tissue dissection is minimized [23] . Hematoma formation occurs in 0.1 to 2.1 percent of men undergoing no scalpel procedures compared with 0.3 to 10.7 percent for incisional technique [24] . Two randomized controlled trials comparing the no-scalpel technique with incisional vasectomies showed a 1.7 to 6.8 reduction in the incidence of bleeding and hematoma formation with the no-scalpel technique [11,24,25] . Infection — Randomized controlled trials comparing no-scalpel and conventional incisional techniques also demonstrate lower wound infection rates for no-scalpel procedures [12,23] . Infections rates for no-scalpel procedures have been reported 0.2 to 0.9 percent for no-scalpel and 1.3 to 4 percent for incisional technique [24] . Prophylactic antibiotics are not generally recommended for no-scalpel technique. Sperm granuloma — A sperm granuloma may form when sperm leaks from the testicular side of an open-ended vas following vasectomy. Less commonly, they may form with extravasation from a cauterized or fulgurated vas. Sperm are highly antigenic and stimulate a significant inflammatory reaction. These granulomas are rarely symptomatic and may be protective to the testis and epididymis. The granuloma are rich in epithelial-lined channels that may vent leaking sperm away from the epididymis and thus protect against increased intraepididymal pressure. Most granulomas are asymptomatic and will ultimately resorb. Granulomas have been implicated in increased rates of post-vasectomy pain and in vas recanalization, however, related to the inflammatory response induced by the sperm antigenic reaction [3] . Post-vasectomy pain syndrome — The main cause of post-vasectomy pain syndrome is believed to be chronic congestive epididymitis. Testicular fluid and sperm production remain constant following vasectomy. The majority of this fluid accumulates in the epididymis, which swells in response. While this may be an asymptomatic occurrence in most men, some will develop a chronic dull ache in the testes, which is made worse by ejaculation. Formation of a sperm granuloma, or nerve entrapment at the vasectomy site, may also cause or contribute to pain. The post-vasectomy pain syndrome is to be distinguished from post-procedure pain, which develops soon after the procedure, is self-limited and may occur in up to 30 percent of vasectomy patients. There is some controversy regarding the definition, and therefore prevalence, of the postvasectomy pain syndrome. Rates for the post-vasectomy pain syndrome have been reported as 0.1 to 0.25 percent [26,27] . However, surveys have found that "troublesome" postvasectomy pain is reported by as many as 15 percent of men, with pain severe enough to impact quality of life in 2 percent; survey respondents, however, may not have been representative of all post-vasectomy men [28,29] .

First-line therapy for postvasectomy pain involves nonsteroidal antiinflammatory medications and warm baths. If this is unsuccessful, local nerve blocks or steroid injections may be performed by a pain specialist. If the post-vasectomy patient's discomfort is localized to a tender, palpable granuloma, this may be excised, followed by fulguration of the leaking end of the vas [30] . Refractory cases may require surgery, including either vasectomy reversal (vasovasostomy) or complete epididymectomy. Vasovasostomy successfully relieves pain in up to 70 percent of patients [31] . These patients, however, will almost always require the use of secondary contraception as a result. Complete epididymal resection is reserved for the most severe cases. Injury to the testicular blood supply is a known complication, resulting in testicular atrophy. Thirty to ninety percent of patients undergoing epididymectomy for post-vasectomy orchalgia will have residual scrotal pain [32] . ASSOCIATED MORBIDITY CONCERNS — Concerns have been raised over potential links between vasectomy and a variety of unproven health consequences. Cardiovascular — A link between vasectomy and atherosclerosis was suggested by a study in monkeys, but this study was later reinterpreted to show no association [33] . Several studies in humans have found no increased risk of cardiovascular disease following vasectomy [27,34,35] . Prostate cancer — Earlier studies suggested that there was an increased incidence of prostate cancer in men who had undergone vasectomy up to 20 years earlier. Two systematic reviews of five cohort studies and 9 to 10 case-control studies published before 2000 found that vasectomy was not associated with an increased risk of prostate cancer [4,36] . A subsequent large case-control study, including over 900 men with prostate cancer, also found no association between prostate cancer and vasectomy, even after more than 25 years post procedure [37] . A small increased rate of prostate cancer following vasectomy, however, was found in a metaanalysis that included five cohort studies and 17 case-control studies [38] . There was a 20 percent increase in calculated relative risk for prostate cancer 30 years after vasectomy (RR 1.23, 95% CI 1.11-1.37). The study could not conclude a causal relationship between vasectomy and prostate cancer, or exclude bias. Patients who undergo vasectomy are more likely to be followed by urologists, and are more likely to be screened for prostate cancer as they age. The American Urological Association no longer recommends informing patients of a possible risk for cancer [39] . Testicular cancer — Large cohort studies have found no increased risk of testicular cancer among vasectomized men [40-42] . Again, any association between the two is likely to be the result of detection bias.

Immune dysfunction — Vasectomy disrupts the blood/testis barrier, resulting in anti-sperm antibodies in 60 to 80 percent of patients [43] . There is no association between anti-sperm antibodies and other immune-complex mediated diseases, such as lupus erythematosus, scleroderma, or rheumatoid arthritis [27] . A large observational study of men who underwent vasectomy an average of thirteen years previously, compared with non-vasectomized men, found no evidence that vasectomy was associated with increased risk for asthma, diabetes mellitus, thyrotoxicosis, multiple sclerosis, myasthenia gravis, inflammatory bowel disease, testicular atrophy, ankylosing spondylitis, or rheumatoid arthritis [44] . Kidney stones — An association has been found between vasectomy and increased risk for kidney stones [45,46] . A case control study found a two fold risk for kidney stones in men younger than age 46 (RR 1.9, 95% CI 1.2-3.1) but not for men aged 46 years or older [45] . The physiologic mechanism for this increased risk is unknown. VASECTOMY REVERSAL — Although vasectomy should be performed only for patients desiring permanent sterility, decisions regarding fertility may change throughout the reproductive years. An effort has been made to prevent irreversible damage at the time of vasectomy. This has led to the development of the open-ended vasectomy. Sealing the testicular side of the cut end of the vas may result in epididymal damage, and decreased vasectomy reversal success. An openended testicular side vas prevents pressure build-up in the epididymis, as there is essentially a "pop-off" valve, allowing for leakage of sperm. The leaked sperm causes an immune response that may result in a sperm granuloma but reduces the risk of concomitant tubular damage. The abdominal end of the vas should be properly sealed or buried to prevent vasectomy failure due to recanalization. This reduces vasectomy failure rates from approximately 7 percent with the pure open-ended technique to 4 percent [14] . Vasectomy is not thought to have appreciable effects on sperm production or seminiferous tubule function. This has been confirmed by intratesticular biopsy up to 15 years postvasectomy [14] . Vasovasostomy — Vasectomy reversal involves reanastomosis of the reproductive tract, ideally at the site of the previous ligation of the vas deferens. A key determinant of success and patency of reversal is the duration of obstruction. A large retrospective study found patency rates (sperm present in ejaculate) of >95 percent, and a pregnancy rate of approximately 75 percent, for men who underwent vasectomy less than 3 years prior to reversal [8] . Both rates decreased in a linear fashion as the duration of obstruction increased. A patency rate of 71 percent and pregnancy rate of 30 percent was reported for men who underwent vasovasostomy 15 years after vasectomy. INFORMATION FOR PATIENTS — Educational materials on this topic are available for patients. (See "Patient information: Vasectomy"). We encourage you to print or e-mail this topic, or to

refer patients to our public web site www.uptodate.com/patients, which includes this and other topics. SUMMARY AND RECOMMENDATIONS Procedure Vasectomy is the most effective available mode of male contraception, with infertility rates exceeding 98 percent. Vasectomy is safer, less costly, and has a shorter recovery time than tubal ligation, though is not performed as frequently. (See "Introduction" above). Patients must understand and accept that vasectomy is a permanent sterilization procedure. Despite counseling, some patients will desire future fertility. Successful reversal is reported in 50 to 70 percent of procedures. (See "Reversibility of procedure" above). Noscalpel vasectomy, using a small perforation rather than incision to mobilize the vas deferens, results in lower rates of bleeding and infection than conventional incisional technique. We suggest vasectomy using the no-scalpel technique, in lieu of the incisional technique, when surgeons have competency skills with the no-scalpel procedure (Grade 2A). (See "Vasectomy approaches" above). Fascial interposition, combined with either ligation or cautery of the epididymal or both ends of the vas, provides the lowest risk of recanalization. (See "Vasal occlusion techniques" above). Postoperative management We suggest not using postoperative prophylactic antibiotics for patients who have undergone a no-scalpel vasectomy (Grade 2C). (See "Infection" above). Postoperatively, patients should apply light pressure and ice to the scrotal area, and maintain bedrest or quiet activity for the first 24 hours. Heavy work or sports should be restricted for one week. (See "Postoperative care" above). A semen analysis should be collected three or four months following vasectomy, and the patient should have had at least 20 ejaculates since the time of vasectomy. We suggest performing only one, rather than multiple, semen analyses at three months post procedure, if the first sample demonstrates azoospermia (Grade 2C). (See "Follow-up to confirm sterility" above) Patients who have motile sperm on two semen samples produced at least 3 months after vasectomy and at least a month apart likely have a failed procedure. Some patients have persistent immotile sperm, and may be considered infertile after seven months if they meet criteria proposed by the British Andrology Society. (See "Follow-up to confirm sterility" above). Complications Post-vasectomy pain syndrome, or post vasectomy orchalgia, occurs in approximately 0.1 percent of men following vasectomy. Warm baths and NSAIDs may provide relief. Surgery is rarely indicated and frequently does not relieve symptoms. (See "Postvasectomy pain syndrome" above). There is no firm evidence that vasectomy causes an increase in cardiovascular disease, cancer of the prostate or testes, or immune disorders. There may be an increase in kidney stone formation. (See "Associated morbidity concerns" above). Reversal Vasectomy reversal (vasovasostomy) is more successful when performed with shorter time interval of vas obstruction, and is more successful following open ended vasectomies, in which the testicular end of the vas is not closed. (See "Vasovasostomy" above).

Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES Peterson, HB, Curtis, KM. Clinical practice. Long-acting methods of contraception. N Engl J Med 2005; 353:2169. Barone, MA, Hutchinson, PL, Johnson, CH, et al. Vasectomy in the United States, 2002. J Urol 2006; 176:232. Awsare, NS, Krishnan, J, Boustead, GB, et al. Complications of vasectomy. Ann R Coll Surg Engl 2005; 87:406. Schwingl, PJ, Guess, HA. Safety and effectiveness of vasectomy. Fertil Steril 2000; 73:923. Jamieson, DJ, Costello, C, Trussell, J, et al. The risk of pregnancy after vasectomy. Obstet Gynecol 2004; 103:848. Hendry, WF. Vasectomy and vasectomy reversal. Br J Urol 1994; 73:337. Sharlip, ID. What is the best pregnancy rate that may be expected from vasectomy reversal? J Urol 1993; 149:1469. Belker, AM, Thomas, AJ Jr, Fuchs, EF, et al. Results of 1,469 microsurgical vasectomy reversals by the Vasovasostomy Study Group. J Urol 1991; 145:505. Potts, JM, Pasqualotto, FF, Nelson, D, et al. Patient characteristics associated with vasectomy reversal. J Urol 1999; 161:1835. Aradhya, KW, Best, K, Sokal, DC. Recent developments in vasectomy. BMJ 2005; 330:296. Dassow, P, Bennett, JM. Vasectomy: an update. Am Fam Physician 2006; 74:2069. Sokal, D, McMullen, S, Gates, D, Dominik, R. A comparative study of the no scalpel and standard incision approaches to vasectomy in 5 countries. The Male Sterilization Investigator Team. J Urol 1999; 162:1621. Li, SQ, Goldstein, M, Zhu, J, Huber, D. The no-scalpel vasectomy. J Urol 1991; 145:341. Sandlow, JI, Winfield, HN, Goldstein, M. Surgery of the scrotum and seminal vesicles. In: Campbell-Walsh Urology, 9th ed, Wein, A, Kavoussi, L, Novick, A, et al (Eds), Saunders, Philadelphia 2000. p.1098. Cook, LA, Van Vliet, H, Lopez, LM, et al. Vasectomy occlusion techniques for male sterilization. Cochrane Database Syst Rev 2007; :CD003991. Labrecque, M, Dufresne, C, Barone, MA, St-Hilaire, K. Vasectomy surgical techniques: a systematic review. BMC Med 2004; 2:21. Sokal, D, Irsula, B, Hays, M, et al. Vasectomy by ligation and excision, with or without fascial interposition: a randomized controlled trial [ISRCTN77781689]. BMC Med 2004; 2:6. Seenu, V, Hafiz, A. Routine antibiotic prophylaxis is not necessary for no scalpel vasectomy. Int Urol Nephrol 2005; 37:763. Griffin, T, Tooher, R, Nowakowski, K, et al. How little is enough? The evidence for post-vasectomy testing. J Urol 2005; 174:29. Hancock, P, McLaughlin, E. British Andrology Society guidelines for the assessment of post vasectomy semen samples (2002). J Clin Pathol 2002; 55:812. 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. Kendrick, JS, Gonzales, B, Huber, DH, et al. Complications of vasectomies in the United States. J Fam Pract 1987; 25:245. Cook, LA, Pun, A, van Vliet, H, et al. Scalpel versus no-scalpel incision for vasectomy. Cochrane Database Syst Rev 2007; :CD004112. Pollack, A. ACOG practice bulletin. Clinical management guidelines for obstetrician-gynecologists. Number 46, September 2003. (Replaces technical bulletin number 222, April 1996). Obstet Gynecol 2003; 102:647. Christensen, P, al-Aqidi, OA, Jensen, FS, Dorflinger, T. [Vasectomy. A prospective, randomized trial of vasectomy with bilateral incision versus the Li vasectomy]. Ugeskr Laeger 2002; 164:2390. McConaghy, P, Paxton, LD, Loughlin, V. Chronic testicular pain following vasectomy. Br J Urol 1996; 77:328. Massey, FJ Jr, Bernstein, GS, O'Fallon, WM, et al. Vasectomy and health. Results from a large cohort study. JAMA 1984; 252:1023. Manikandan, R, Srirangam, SJ, Pearson, E, Collins, GN. Early and late morbidity after vasectomy: a comparison of chronic scrotal pain at 1 and 10 years. BJU Int 2004; 93:571. McMahon, AJ, Buckley, J, Taylor, A, et al. Chronic testicular pain following vasectomy. Br J Urol

1992; 69:188. Schmidt, SS. Spermatic grauloma: an often painful lesion. Fertil Steril 1979; 31:178. Nangia, AK, Myles, JL, Thomas, AJ JR. Vasectomy reversal for the post-vasectomy pain syndrome: a clinical and histological evaluation. J Urol 2000; 164:1939. Padmore, DE, Norman, RW, Millard, OH. Analyses of indications for and outcomes of epididymectomy. J Urol 1996; 156:95. Clarkson, TB, Alexander, NJ, Morgan, TM. Atherosclerosis of cynomolgus monkeys hyper- and hyporesponsive to dietary cholesterol. Lack of effect of vasectomy. Arteriosclerosis 1988; 8:488. Giovannucci, E, Tosteson, TD, Speizer, FE, et al. A long-term study of mortality in men who have undergone vasectomy. N Engl J Med 1992; 326:1392. Coady, SA, Sharrett, AR, Zheng, ZJ, et al. Vasectomy, inflammation, atherosclerosis and long-term followup for cardiovascular diseases: no associations in the atherosclerosis risk in communities study. J Urol 2002; 167:204. Bernal-Delgado, E, Latour-Perez, J, Pradas-Arnal, F, Gomez-Lopez, LI. The association between vasectomy and prostate cancer: a systematic review of the literature. Fertil Steril 1998; 70:191. Cox, B, Sneyd, MJ, Paul, C. Vasectomy and risk of prostate cancer. JAMA 2002; 287:3110. Dennis, LK, Dawson, DV, Resnick, MI. Vasectomy and the risk of prostate cancer: a meta-analysis examining vasectomy status, age at vasectomy, and time since vasectomy. Prostate Cancer Prostatic Dis 2002; 5:193. www.auanet.org/about/policy/services.cfm#vasectomy. Accessed December 14, 2007. Moller, H, Knudsen, LB, Lynge, E. Risk of testicular cancer after vasectomy: cohort study of over 73 000 men. BMJ 1994; 309:295. Hewitt, G, Logan, CJ, Curry, RC. Does vasectomy cause testicular cancer? Br J Urol 1993; 71:607. Strader, CH, Weiss, NS, Daling, JR. Vasectomy and the incidence of testicular cancer. Am J Epidemiol 1988; 128:56. Aitken, RJ, Parslow, JM, Hargreave, TB, Hendry, WF. Influence of antisperm antibodies on human sperm function. Br J Urol 1988; 62:367. Goldacre, MJ, Wotton, CJ, Seagroatt, V, Yeates, D. Immune-related disease before and after vasectomy: an epidemiological database study. Hum Reprod 2007; 22:1273. Kronmal, RA, Krieger, JN, Coxon, V, et al. Vasectomy is associated with an increased risk for urolithiasis. Am J Kidney Dis 1997; 29:207. Kronmal, RA, Alderman, E, Krieger, JN, et al. Vasectomy and urolithiasis. Lancet 1988; 1:22. GRAPHICS Location of vasectomy Grade 2A recommendation A Grade 2A recommendation is a weak recommendation, and the best action may differ depending on circumstances or patient or societal values. Explanation: A Grade 2 recommendation is a weak recommendation. It means "this is our suggestion, but you may want to think about it." It is unlikely that you should follow the suggested approach in all your patients, and you might reasonably choose an alternative approach. For Grade 2 recommendations, benefits and risks may be finely balanced, or the benefits and risks may be uncertain. In deciding whether to follow a Grade 2 recommendation in an individual patient, you may want to think about your patient's values and preferences or about your patient's risk aversion.

Grade A means that the best estimates of the critical benefits and risks come from consistent data from well-performed, randomized, controlled trials or overwhelming data of some other form (eg, well-executed observational studies with very large treatment effects). Further research is unlikely to have an impact on our confidence in the estimates of benefit and risk. Recommendation grades 1. Strong recommendation: Benefits clearly outweigh the risks and burdens (or vice versa) for most, if not all, patients 2. Weak recommendation: Benefits and risks closely balanced and/or uncertain Evidence grades A. High-quality evidence: Consistent evidence from randomized trials, or overwhelming evidence of some other form B. Moderate-quality evidence: Evidence from randomized trials with important limitations, or very strong evidence of some other form C. Low-quality evidence: Evidence from observational studies, unsystematic clinical observations, or from randomized trials with serious flaws For a complete description of our grading system, please see the UpToDate editorial policy which can be found by clicking "About UpToDate" and then selecting "Policies". Grade 2C recommendation A Grade 2C recommendation is a very weak recommendation; other alternatives may be equally reasonable. Explanation: A Grade 2 recommendation is a weak recommendation. It means "this is our suggestion, but you may want to think about it." It is unlikely that you should follow the suggested approach in all your patients, and you might reasonably choose an alternative approach. For Grade 2 recommendations, benefits and risks may be finely balanced, or the benefits and risks may be uncertain. In deciding whether to follow a Grade 2 recommendation in an individual patient, you may want to think about your patient's values and preferences or about your patient's risk aversion. Grade C means the evidence comes from observational studies, unsystematic clinical experience, or from randomized, controlled trials with serious flaws. Any estimate of effect is uncertain. Recommendation grades 1. Strong recommendation: Benefits clearly outweigh the risks and burdens (or vice versa) for most, if not all, patients 2. Weak recommendation: Benefits and risks closely balanced and/or uncertain

Evidence grades A. High-quality evidence: Consistent evidence from randomized trials, or overwhelming evidence of some other form B. Moderate-quality evidence: Evidence from randomized trials with important limitations, or very strong evidence of some other form C. Low-quality evidence: Evidence from observational studies, unsystematic clinical observations, or from randomized trials with serious flaws For a complete description of our grading system, please see the UpToDate editorial policy which can be found by clicking "About UpToDate" and then selecting "Policies".