Intravasal injection of formed-in-place medical grade silicone rubber for vas occlusion

Practice and development of male contraception: European Academy of Andrology and American Society of Andrology guidelines

BACKGROUNDS

Despite a wide spectrum of contraceptive methods for women, the unintended pregnancy rate remains high (45% in the US), with 50% resulting in abortion. Currently, 20% of global contraceptive use is male-directed, with a wide variation among countries due to limited availability and lack of efficacy. Worldwide studies indicate that >50% of men would opt to use a reversible method, and 90% of women would rely on their partner to use a contraceptive. Additional reasons for novel male contraceptive methods to be available include the increased life expectancy, sharing the reproductive risks among partners, social issues, the lack of pharma industry involvement and the lack of opinion makers advocating for male contraception.

AIM

The present guidelines aim to review the status regarding male contraception, the current state of the art to support the clinical practice, recommend minimal requirements for new male contraceptive development and provide and grade updated, evidence-based recommendations from the European Society of Andrology (EAA) and the American Society of Andrology (ASA).

METHODS

An expert panel of academicians appointed by the EAA and the ASA generated a consensus guideline according to the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) system.

RESULTS

Sixty evidence-based and graded recommendations were produced on couple-centered communication, behaviors, barrier methods, semen analysis and contraceptive efficacy, physical agents, surgical methods, actions before initiating male contraception, hormonal methods, non-hormonal methods, vaccines, and social and ethical considerations.

CONCLUSION

As gender roles transform and gender equity is established in relationships, the male contribution to family planning must be facilitated. Efficient and safe male-directed methods must be evaluated and introduced into clinical practice, preferably reversible, either hormonal or non-hormonal. From a future perspective, identifying new hormonal combinations, suitable testicular targets, and emerging vas occlusion methods will produce novel molecules and products for male contraception.

The future of male contraception: a fertile ground

The continued and rapid expansion of the Earth’s population mandates the need for safe and effective measures of contraception. While a plethora of options exist for women, methods of contraception for the male partner are limited to condoms and vasectomy. The sequela of this discrepancy has led to the family planning burden falling disproportionately on the female partner. For the past several decades, extensive research has been undertaken exploring the feasibility of hormonal male contraception. This proposed method of contraception has focused on suppressing spermatogenesis by exploiting the hypothalamic-pituitary-gonadal (HPG) axis. Beginning with proof of concept studies in the early nineties, administration of testosterone in healthy male subjects has been shown to be an efficacious method of inducing sterility. Owing to ethnic differences in spermatogenesis suppression and the comparatively low rate of azoospermia in Caucasian men with androgen-only regimens, investigators have explored the addition of progestins to further enhance the efficacy of hormonal contraception. Though studies have revealed promise with androgen-progestin regimens, the lack of long-term studies has precluded the development of a marketable product. Recently, more research has been directed towards identifying non-hormonal alternatives to male contraception. These non-hormonal options have ranged from the development of devices facilitating reversible occlusion of the vas deferens lumen to medications disrupting various pathways in the process of spermatogenesis. Underlying the development of hormonal and non-hormonal strategies is the shared enthusiasm men and women have towards these male directed methods. The willingness of couples to pursue these alternatives combined with the global need to reduce the psychological and socioeconomic implications of unintended pregnancy ensures that research will continue to bring this goal to fruition.

Vasectomy occlusion techniques for male sterilization

BACKGROUND

Vasectomy is an increasingly popular and effective family planning method. A variety of vasectomy techniques are used worldwide, including vas occlusion techniques (excision and ligation, thermal or electrocautery, and mechanical and chemical occlusion methods), as well as vasectomy with vas irrigation or with fascial interposition. Vasectomy guidelines largely rely on information from observational studies. Ideally, the choice of vasectomy techniques should be based on the evidence from randomized controlled trials (RCTs).

OBJECTIVES

The objective of this review was to compare the effectiveness, safety, acceptability and costs of vasectomy techniques for male sterilization.

SEARCH METHODS

In February 2014, we updated the searches of CENTRAL, MEDLINE, POPLINE and LILACS. We looked for recent clinical trials in ClinicalTrials.gov and the International Clinical Trials Registry Platform. Previous searches also included EMBASE. For the initial review, we searched the reference lists of relevant articles and book chapters.

SELECTION CRITERIA

We included RCTs comparing vasectomy techniques, which could include suture ligature, surgical clips, thermal or electrocautery, chemical occlusion, vas plugs, vas excision, open-ended vas, fascial interposition, or vas irrigation.

DATA COLLECTION AND ANALYSIS

We assessed all titles and abstracts located in the literature searches. Two reviewers independently extracted data from articles identified for inclusion. Outcome measures include contraceptive efficacy, safety, discontinuation, and acceptability. Peto odds ratios (OR) with 95% confidence intervals (CI) were used for dichotomous outcomes, such as azoospermia. The mean difference (MD) was used for the continuous variable of operating time.

MAIN RESULTS

Six studies met the inclusion criteria. One trial compared vas occlusion with clips versus a conventional vasectomy technique. No difference was found in failure to reach azoospermia (no sperm detected). Three trials examined vasectomy with vas irrigation. Two studies looked at irrigation with water versus no irrigation, while one examined irrigation with water versus the spermicide euflavine. None found a difference between the groups for time to azoospermia. However, one trial reported that the median number of ejaculations to azoospermia was lower in the euflavine group compared to the water irrigation group. One high-quality trial compared vasectomy with fascial interposition versus vasectomy without fascial interposition. The fascial interposition group was less likely to have vasectomy failure. Fascial interposition had more surgical difficulties, but the groups were similar in side effects. Lastly, one trial found that an intra-vas was less likely to produce azoospermia than was no-scalpel vasectomy. More men were satisfied with the intra-vas device, however.

AUTHORS' CONCLUSIONS

For vas occlusion with clips or vasectomy with vas irrigation, no conclusions can be made as those studies were of low quality and underpowered. Fascial interposition reduced vasectomy failure. An intra-vas device was less effective in reducing sperm count than was no-scalpel vasectomy. RCTs examining other vasectomy techniques were not available. More and better quality research is needed to examine vasectomy techniques.

Vasectomy occlusion techniques for male sterilization

BACKGROUND

Vasectomy is an increasingly popular and effective family planning method. A variety of vasectomy techniques are used worldwide, including various vas occlusion techniques (excision and ligation, thermal or electrocautery, and mechanical and chemical occlusion methods), as well as vasectomy with vas irrigation or with fascial interposition. Vasectomy guidelines largely rely on information from observational studies. Ideally, the choice of vasectomy techniques should be based on the best available evidence from randomized controlled trials.

OBJECTIVES

The objective of this review was to compare the effectiveness, safety, acceptability and costs of vasectomy techniques for male sterilization.

SEARCH STRATEGY

We searched the computerized databases of CENTRAL, MEDLINE, EMBASE, POPLINE and LILACS. In addition, we searched the reference lists of relevant articles and book chapters.

SELECTION CRITERIA

We included randomized controlled trials comparing vasectomy techniques.

DATA COLLECTION AND ANALYSIS

We assessed all titles and abstracts located in the literature searches. Two reviewers independently extracted data from articles identified for inclusion. Outcome measures include contraceptive efficacy, safety, discontinuation, and acceptability.

MAIN RESULTS

Six studies met the inclusion criteria. One trial compared vas occlusion with clips versus a conventional vasectomy technique. No difference was found in failure to reach azoospermia. Three trials examined vasectomy with vas irrigation. Two studies looked at irrigation with water versus no irrigation, while one examined irrigation with water versus the spermicide euflavine. None found a difference between the groups for time to azoospermia. However, one trial reported that the median number of ejaculations to azoospermia was lower in the euflavine group compared to the water irrigation group. One high-quality trial compared vasectomy with fascial interposition versus vasectomy without fascial interposition. The fascial interposition group was less likely to have vasectomy failure. Fascial interposition had more surgical difficulties, but the groups were similar in side effects. Lastly, one trial found that an intra-vas was less likely to produce azoospermia than was no-scalpel vasectomy. More men were satisfied with the intra-vas device, however.

AUTHORS' CONCLUSIONS

For vas occlusion with clips or vasectomy with vas irrigation, no conclusions can be made as those studies were of low quality and underpowered. Fascial interposition reduced vasectomy failure. An intra-vas device was less effective in reducing sperm count than was no-scalpel vasectomy. Randomized controlled trials examining other vasectomy techniques were not available. More and better quality research is needed to examine vasectomy techniques.

[Male and female sterilization techniques: Summary of ANAES assessments (May 2005)]

OBJECTIVE

To summarize assessments carried out by ANAES on male and female sterilization techniques. The summary was requested by the French Health Directorate after the law authorizing sterilization as a means of contraception was passed.

RESULTS (FEMALE STERILIZATION)

(i) EFFICACY of tubal ligation, electrocoagulation, clips or rings: the annual pregnancy rate is 0-2% depending on the study, with no significant difference between techniques. No data were found on fimbriectomy. (ii) EFFICACY of a hysteroscopically placed micro-insert device: no pregnancies were observed in patients with bilateral tube obstruction diagnosed by hysterosalpingography at 3 or at 6 months after placement (placement rate: 87-89%). (iii) SAFETY of tubal ligation, electrocoagulation, clips or rings: (a) By approach: There was no difference in the incidence of major complications between laparoscopy and minilaparotomy but there were significantly fewer minor complications with laparoscopy than with minilaparotomy. There were significantly more major complications with culdoscopy than with minilaparotomy and significantly more minor complications than with laparoscopy. (b) By operative technique: major and minor complications were significantly more common with the Pomeroy technique than with electrocoagulation; the difference could be due to the approach used. No data were available on fimbriectomy. (iv) SAFETY of a hysteroscopically placed micro-insert device: there were 11 cases of myometrial or tubal perforation among 734 patients (with device displacement into the peritoneal cavity in 3 cases).

RESULTS (MALE STERILIZATION)

(i)

EFFICACY

efficacy varied from 84% to 100% depending on the approach and the mode of vas deferens obstruction. There was no significant difference in efficacy according to approach (transcutaneous or scrotal). However, no conclusion could be drawn on the comparative efficacy of the occlusion techniques used from published data. (ii)

SAFETY

the rate of postoperative complications was low, below 10% in most series. Complications were benign and only rarely necessitated surgical revision.

CONCLUSION

The advantage of sterilization methods is that they lack any permanent contraindication. They should be presented as being generally irreversible. Fimbriectomy is not recommended for female sterilization. Laparoscopy is the preferred approach. Sterilization by hysteroscopic placement of a micro-insert device should be restricted to cases presenting a risk on laparoscopy; the technique should be re-assessed in 2006. The two approaches used for male sterilization are technically similar and do not seem to differ in efficacy. The Public Health Code states that "Fallopian tube or deferens duct ligation for contraceptive purposes is not allowed in minors" and that ligation "cannot be performed unless the adult involved has given his/her informed and motivated consent, expressed after taking into consideration clear, complete information on the consequences of the procedure". A waiting period of four months must follow the moment the decision to sterilize is taken and consent is given. An informed consent form must be signed. Sterilization in young or nulliparous women should be proposed with the greatest prudence and with many reservations.

The use of URYX for reversible vasectomy in a rabbit model

URYX is a biocompatible polymer of ethylene vinyl alcohol dissolved in a dimethyl sulfoxide (DMSO) carrier to allow injection of a very low-viscosity fluid into tissue. Once the material comes into contact with body tissue or fluid, the DMSO rapidly dissipates from the polymer, which results in a precipitate of a coherent solid mass. The purpose of the present study was to determine whether URYX can effectively occlude the vas deferens and whether patency can be restored by redissolving the URYX in vivo using the solvent DMSO. Eight male New Zealand White rabbits (age range, 25-41 weeks; mean age, 33.9 +/- 7.5 weeks; mean weight, 4.0 +/- 0.2 kg) were used in 2 experiments (E1 and E2). In E1, 3 rabbits underwent unilateral vasectomy, and the contralateral vas was injected with either 0.05 or 0.10 mL of URYX, to determine the amount of URYX required to cause obstruction. Two animals underwent bilateral vasectomy, to serve as controls. In E2, 3 animals underwent bilateral URYX injection and were compared with the bilateral vasectomy control rabbits used in E1. After 1 month of initial bilateral URYX treatment, all animals in E2 underwent attempted unilateral reversal with 1.5 mL of DMSO injected into 1 occluded vas deferens. Two end points were evaluated-a clinical end point assessed by semen analyses and a pathological end point assessed by histological analysis of treated tissues, to assess for safety. A 1.5-cm infrapubic incision was made to expose both vasa in anesthetized rabbits. The vasal injection of URYX was performed with a 30-gauge needle. Vasectomy was performed by excision of a 1-cm segment of the vas deferens and subsequent ligation with a 6-0 prolene suture. Semen was collected using an artificial vagina 2-3 times/wk before and 1 month later, after injection treatments and vasectomy. Manual sperm counts were performed. All animals were sacrificed, and tissues (distal vas, injection site, proximal vas, cauda epididymis, caput epididymis, and testis) were harvested and examined for the presence of URYX. The inflammatory response of the wall and adventitia of the vas deferens was given a score (0-15) based on the sum of grades (0 = none, 1 = mild, 2 = moderate, and 3 = severe) for the following categories: foreign body giant cell reaction, granulation tissue, lymphocytes, eosinophils, and scarring, as evaluated by a single pathologist (J.M.). Vasal injection with 0.05 mL of URYX was not sufficient to cause occlusion. Both animals injected with 0.1 mL of URYX were effectively occluded. The injection of occluded vasa with DMSO did not dissolve the URYX plug in the vas lumen. There was no significant difference in vasal inflammatory response scores between vasal units treated with URYX only and vasal units in the vasectomy model. Vasal units subjected to URYX followed by DMSO demonstrated greater inflammatory response scores than vasal units treated with URYX followed by normal saline, URYX alone, or vasectomy. Epididymal and testicular histology remained unaffected in all vasal units in E1. The vasal units in E2 subjected to URYX followed by normal saline showed no histological abnormalities of the epididymis and testis. However, those vasal units subjected to URYX followed by DMSO in E2 showed evidence of adhesions, necrosis, and degenerating cells in the epididymis and a focal foreign body giant cell reaction in the testis. The bilateral vasal injection of URYX can result in azoospermia in the rabbit model. Reversal with subsequent DMSO injection was not achieved. A minimal inflammatory response of the vas deferens was observed with URYX injection alone; however, DMSO following URYX injection resulted in increased vasal inflammation, in addition to epididymal and testicular changes.

Vasectomy occlusion techniques for male sterilization

BACKGROUND

Vasectomy is an increasingly popular and effective family planning method. A variety of vasectomy techniques are used worldwide including various vas occlusion techniques (excision and ligation, thermal or electrocautery, and mechanical and chemical occlusion methods), vas irrigation and fascial interposition. Vasectomy guidelines largely rely on information from observational studies. Ideally, the choice of vasectomy techniques should be based on the best available evidence from randomized controlled trials.

OBJECTIVES

The objective of this review was to compare the effectiveness, safety, acceptability and costs of vasectomy techniques for male sterilization.

SEARCH STRATEGY

We searched the computerized databases the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Popline and LILACS. In addition, we searched the reference lists of relevant articles and book chapters.

SELECTION CRITERIA

We included randomized controlled trials and controlled clinical trials comparing vasectomy techniques.

DATA COLLECTION AND ANALYSIS

We assessed all titles and abstracts located in the literature searches and two reviewers independently extracted articles identified for inclusion. Data were presented in the text of the review. Outcome measures include contraceptive efficacy, safety, discontinuation, and acceptability.

MAIN RESULTS

Two trials compared vas occlusion with clips versus a conventional vasectomy technique; both were of poor quality. Neither trial found a difference between the two groups with regard to the primary outcome of failure to reach azoospermia. Four trials examined vas irrigation: three compared water irrigation with no irrigation and one compared water irrigation with euflavine. All of the trials were of poor quality. None of the trials found a significant difference between the groups with respect to the primary outcome of time to azoospermia. However, one trial found that the median number of ejaculations to azoospermia was significantly lower in the euflavine group compared to the water irrigation group. The one trial that compared vasectomy with fascial interposition versus vasectomy without fascial interposition was a high quality, large study that has only been partially reported at the time of this review. The fascial interposition group was significantly more likely to be related to vasectomy success (azoospermia) at 22 weeks. However, fascial interposition also was associated with significantly more surgical difficulties.

REVIEWERS' CONCLUSIONS

No conclusions can be made about the effectiveness, safety, acceptability and costs of vas occlusion technique or vas irrigation as studies that examined these were of low quality and underpowered. Fascial interposition is associated with improved vasectomy success but is associated with some increased surgical difficulty. Randomized controlled trials examining other vasectomy techniques were not available. More research is required to examine vasectomy techniques.

Family planning needs: new opportunities, emergency contraception and other new technologies

Modern contraception is considered to be one the major advances of the 20th century. Yet, as the next century begins, it is estimated that there is still a largely unmet need for contraception, with millions of couples worldwide who express a wish to limit the number of their children but do not use or are not satisfied with their contraceptive method. While the reasons are numerous, it is clear that there is a need for improved and new methods which are easier to use, under the user's control, with fewer side-effects and responding to the needs of different groups of users, including men. To respond to this need, current contraceptive research and development efforts focus on five main areas: emergency post-coital methods, user-controlled long-acting methods, dual protection methods against both pregnancy and sexually transmitted infections, methods for men, and methods with fewer side-effects including some that are more targeted to specific reproductive biological events. A number of leads are presented which are at various stages of development. Concluding remarks stress the numerous challenges of contraceptive development, not the least of which is the vision required of what the needs of future generations will be, since it takes 10-15 years to bring a new contraceptive to the market. More fundamentally, overall progress towards reducing the unmet need for contraception will depend on the status of women, specifically their decision-making power, and access to education and income.

Efficacy of percutaneous vas occlusion compared with conventional vasectomy

OBJECTIVES

To determine the efficacy, evaluate the safety and assess side-effects (swelling, haematoma and pain) of percutaneous vas occlusion compared with vasectomy in Dutch men.

PATIENTS AND METHODS

Vas occlusion and vasectomy procedures (attempted in 58 and 50 men, respectively) were conducted at the University Hospital Maastricht. The men returned 1 week after the procedure, underwent a clinical examination and completed a questionnaire assessing subjectively any pain, swelling and haematoma. The men were asked to return for semen analysis at 6 and 12 weeks and, if necessary, for additional analyses until they were azoospermic.

RESULTS

The vas occlusion procedure was completed on both vasa in 49 of the 58 men (84%) in whom it was attempted. Significantly more (P < 0.001) men were azoospermic after vasectomy (48 of 50) than after vas occlusion (only four). Men undergoing vas occlusion reported significantly less pain (P = 0.02), swelling (P = 0.01) and haematoma (P = 0.04) after the procedure than did men undergoing vasectomy.

CONCLUSION

Men undergoing vas occlusion would not have been able to rely on the method for contraception. From this study, vas occlusion, at least in its current form, is an unsuitable method of male contraception. Not only was the efficacy poor, but constraints in delivering the method in its current state would probably limit its utility, especially in situations where resources are limited.

Repeated vas occlusion and non-invasive reversal with styrene maleic anhydride for male contraception in langur monkeys

The feasibility of a spacing method for contraception, using Styrene Maleic Anhydride (SMA) as a vas occlusive agent, has been assessed in male langur monkeys. The vas deferens of 6 animals were occluded with 60 mg SMA in 120 microL DMSO. After 150 days, the occlusion was reversed by a technique which involved palpation, percutaneous electrical stimulation, forced vibratory movement, suprapubic percussion and per-rectal digital massage of the vas segments. The vas deferens were then re-occluded with SMA and reversed by the non-invasive method after three consecutive azoospermic samples. The second vas occlusion resulted in uniform azoospermia after the third ejaculation and reversal caused the reappearance of spermatozoa in the semen to severe oligozoospermic levels in the first two ejaculations and rising to normospermia in the subsequent ejaculations. Ultrastructure of the spermatozoa by SEM and TEM and sperm function tests revealed that the spermatozoa had recovered normal morphology. Vas morphology also regained a normal pseudostratified columnar epithelium containing basal and principal cells. The results suggest that the SMA-based spacing technique for male contraception could be extrapolated to the human by use of no-scalpel injection and non-invasive reversal.

The relationship between the vas volume and the anatomic size of the vas deferens

The anatomic sizes of 210 vas segments from 107 volunteers of vasectomy were measured by computerized image graphic technique with microphotography. The mean equivalent-round, outer and inner diameters of the vas were 2.17 +/- 0.20 mm and 0.56 +/- 0.08 mm, respectively. The calculated thickness of vas wall was 0.81 +/- 0.21 mm. The maximal volumes of 124 vas segments (1 cm in length) were tested by injecting colored solution into vas lumen until vas rupture. The mean rupture volume of 1 cm vas lumen was 0.05 +/- 0.007 mL. A significant influence of the thickness of vas wall (p < 0.05) and body height (p < 0.05) on the rupture volume was noticed in stepwise regression analysis. A tunnel-like rupturing pattern was observed in morphological observation. The obtained rupture volume provides a security line in determining the injection volume of occlusive material or the size of the implanted contraceptive device.