Scalpel versus no-scalpel incision for vasectomy

BACKGROUND

Currently, the two most common surgical techniques for approaching the vas during vasectomy are the incisional method and the no-scalpel technique. Whereas the conventional incisional technique involves the use of a scalpel to make one or two incisions, the no-scalpel technique uses a sharp-pointed, forceps-like instrument to puncture the skin. The no-scalpel technique aims to reduce adverse events, especially bleeding, bruising, hematoma, infection and pain and to shorten the operating time.

OBJECTIVES

The objective of this review was to compare the effectiveness, safety, and acceptability of the incisional versus no-scalpel approach to the vas.

SEARCH METHODS

In February 2014, we searched the computerized databases 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 in EMBASE. For the initial review, we searched the reference lists of relevant articles and book chapters.

SELECTION CRITERIA

Randomized controlled trials and controlled clinical trials were included in this review. No language restrictions were placed on the reporting of the trials.

DATA COLLECTION AND ANALYSIS

We assessed all titles and abstracts located in the literature searches and two authors independently extracted data from the articles identified for inclusion. Outcome measures included safety, acceptability, operating time, contraceptive efficacy, and discontinuation. We calculated Peto odds ratios (OR) with 95% confidence intervals (CI) for the dichotomous variables.

MAIN RESULTS

Two randomized controlled trials evaluated the no-scalpel technique and differed in their findings. The larger trial demonstrated less perioperative bleeding (OR 0.49; 95% CI 0.27 to 0.89) and pain during surgery (OR 0.75; 95% CI 0.61 to 0.93), scrotal pain (OR 0.63; 95% 0.50 to 0.80), and incisional infection (OR 0.21; 95% CI 0.06 to 0.78) during follow up than the standard incisional group. Both studies found less hematoma with the no-scalpel technique (OR 0.23; 95% CI 0.15 to 0.36). Operations using the no-scalpel approach were faster and had a quicker resumption of sexual activity. The smaller study did not find these differences; however, the study could have failed to detect differences due to a small sample size as well as a high loss to follow up. Neither trial found differences in vasectomy effectiveness between the two approaches to the vas.

AUTHORS' CONCLUSIONS

The no-scalpel approach to the vas resulted in less bleeding, hematoma, infection, and pain as well as a shorter operation time than the traditional incision technique. No difference in effectiveness was found between the two approaches.

Common questions about vasectomy

Vasectomy offers a safe, effective, and permanent method of male contraception, with an overall failure rate of less than 1% in pooled studies. Men older than 30 years in a stable, committed relationship appear to be the best candidates for vasectomy. The no-scalpel technique reduces operative complications, shortens operative time, and hastens resumption of sexual activity. Use of a jet injector instead of a needle to provide local anesthesia (no-needle vasectomy) may reduce pain. Bleeding and infection are short-term complications of vasectomy; long-term complications include sperm granuloma and postvasectomy pain syndrome. One postvasectomy semen analysis demonstrating azoospermia performed after three months and 20 ejaculations is sufficient to establish sterility. Vasectomy reversal is more likely to be successful if performed less than 15 years after vasectomy and in men whose female partner is younger than 40 years.

Use of surgical clips prevents suture slippage when ligating folded vas deferens during vasectomy

OBJECTIVE

We describe a technique of surgical clip placement, which prevents slippage when ligating the folded vas deferens during vasectomy.

METHODS

We utilized this technique in 25 consecutive vasectomy procedures. After isolating the vas, two mosquito clamps are placed approximately 2 cm-3 cm apart and a small 5 mm-10 mm section of full thickness vas is removed. The lumen of each cut end is cauterized. Surgical clips (Ethicon Ligaclip Extra LS-200, Medium) are placed at approximately 2 mm, 3 mm and 15 mm (on the opposite side of the hemostat) from each cut end. By rotating the hemostat, the vas is folded on itself and a 3-0 or 4-0 chromic suture is placed between the two proximal clips and distal to the third clip. The hemostat is carefully removed and the vas gently ligated.

RESULTS

A single surgeon noted no instances of suture slippage in 25 consecutive vasectomies. All patients underwent postoperative semen analysis that showed azoospermia.

CONCLUSION

Placement of the ligating suture between two proximal clips and past a third distal clip prevents suture slippage when ligating the folded end of the vas deferens during vasectomy.

[No-scalpel vasectomy. Profile of acceptance and results]

BACKGROUND

Men have few effective methods for birth control. The surgical method vasectomy is highly safe and effective, although in Mexico represents only 2.4% of all contraceptive methods used.

OBJECTIVE

To determine the characteristics, complications and results of the men who requested and underwent no-scalpel vasectomy in the Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, in México.

MATERIAL AND METHOD

Retrospective cohort study with data of clinical records of men who underwent no-scalpel vasectomy from 2003 to 2007. Sociodemographic and clinical variables, and complications reported as well as espermatobioscopy data were included. Descriptive analysis was performed of different variables and chi squared test between proportions.

RESULTS

A total of 596 no-scalpel vasectomies were performed. The average age was 36.5 years and 13.4 of schooling, 86.9% were married with 9.6 years of union. Socioeconomic status was as follows: medium (25%), middle high (20.1%), and high (24.7%). The 94.3% of men requested the no-scalpel vasectomy because of satisfied fertility and 5.7% by morbidity in his couple. The complications were as follows: epididymitis (2.2%), mild haematoma (1.5%) and contact dermatitis (0.2%). The surgical complications were significantly more frequent for the group with varicocele compared with the normal men group (p < 0.05). Azoospermia was achieved in 99.1% of men at 18 weeks after the no-scalpel vasectomy. Early recanalization occurred in 0.5% of men. There were no pregnancies.

CONCLUSIONS

The profile of men who requested no-scalpel vasectomy was in a great proportion healthy, in the fourth decade of life, with high school or greater, satisfied fertility and high socioeconomic status. No-scalpel vasectomy is a method of fertility planning very effective with low morbidity.

Scalpel versus no-scalpel incision for vasectomy

BACKGROUND

Currently, the two most common surgical techniques for approaching the vas during vasectomy are the incisional method and the no-scalpel technique. Whereas the conventional incisional technique involves the use of a scalpel to make one or two incisions, the no-scalpel technique uses a sharp-pointed, forceps-like instrument to puncture the skin. The no-scalpel technique aims to reduce adverse events, especially bleeding, bruising, hematoma, infection and pain and to shorten the operating time.

OBJECTIVES

The objective of this review was to compare the effectiveness, safety, and acceptability of the incisional versus no-scalpel approach to the vas.

SEARCH STRATEGY

We searched the computerized databases of CENTRAL, MEDLINE, EMBASE, POPLINE and LILACS in May 2006. In addition, we searched the reference lists of relevant articles and book chapters.

SELECTION CRITERIA

Randomized controlled trials and controlled clinical trials were included in this review. No language restrictions were placed on the reporting of the trials.

DATA COLLECTION AND ANALYSIS

We assessed all titles and abstracts located in the literature searches and two authors independently extracted data from the articles identified for inclusion. Outcome measures included safety, acceptability, operating time, contraceptive efficacy, and discontinuation.

MAIN RESULTS

Two randomized controlled trials evaluated the no-scalpel technique and differed in their findings. The larger trial demonstrated less perioperative bleeding (Odds ratio (OR) 0.49; 95% Confidence Interval (CI) 0.27 to 0.89) and pain during surgery (OR 0.75; 95% CI 0.61 to 0.93), scrotal pain (OR 0.63; 95% 0.50 to 0.80), and incisional infection (OR 0.21; 95% CI 0.06 to 0.78) during follow up than the standard incisional group. Both studies found less hematoma with the no-scalpel technique (OR 0.23; 95% CI 0.15 to 0.36). Operations using the no-scalpel approach were faster and had a quicker resumption of sexual activity. The smaller study did not find these differences; however, the study could have failed to detect differences due to a small sample size as well as a high loss to follow up. Neither trial found differences in vasectomy effectiveness between the two approaches to the vas.

AUTHORS' CONCLUSIONS

The no-scalpel approach to the vas resulted in less bleeding, hematoma, infection, and pain as well as a shorter operation time than the traditional incision technique. No difference in effectiveness was found between the two approaches.

Persistent Motile Sperm After Ligation Band Vasectomy

PURPOSE

We evaluated the efficacy and mechanism of failure in a small case series of VasClip vasectomies.

MATERIALS AND METHODS

Between September 2003 and March 2004, 8 patients underwent elective vasectomy using the VasClip ligation band. Microscopic semen analysis was done a minimum of 4 weeks postoperatively and after at least 15 ejaculations. The number of sperm and motility were quantified in 15 or more high power fields. Successful vasectomy was defined as 2 consecutive postoperative unspun semen analyses containing no sperm. Patients with failed vasectomy underwent bilateral surgical removal of the vas deferens segments containing the ligation band for gross and histological analysis.

RESULTS

Six of 8 patients (75%) were deemed azoospermic after 2 semen analyses at a mean followup of 7 and 11 weeks postoperatively, respectively. Two of 8 patients (25%) had semen analyses containing multiple motile sperm after vasectomy. In the 2 failed cases 1 side was patent, as demonstrated by vasal cannulation and irrigation with dilute methylene blue despite a well positioned, intact and secure ligation band. Histological analysis showed extravasation and sperm granuloma on the patent side.

CONCLUSIONS

The VasClip was found to fail at an unexpectedly high rate. Pathological analysis suggests sperm extravasation and fistula tract formation as the mechanism. One failure resulted in an unwanted pregnancy, which demonstrates the need for patient counseling regarding postoperative followup.

No scalpel vasectomy--an overview

Male sterilisation is less popular because of fear of loss of virility and loss of physical strength. No scalpel vasectomy is a surgical attempt to reduce complications and thereby allays the fear in the minds of the couples. Despite the introduction of the advanced technique the acceptance of male sterilisation has not gone up. Though with aggressive IEC compaign has failed to produce the desired result, but a camp based approach was successfully adopted in some states of India. Technique of no scalpel vasectomy has been summarised in the article with diagrams. Some postoperative instructions should be given to the client after discharge. No scalpel vasectomy is the gold standard for vasectomy today. Training is mandatory for experienced surgeons. Government of India funds and supports both the training and service activity.

No scalpel vasectomy advocacy and community mobilisation--a personal experience

The so called myths and taboos among the people of India are obstactes controlling population explosion and thereby the nation is being handicapped with economic development. To propagate awareness and information, the NSV Resource Center took up organising mega camps for the acceptance of NSV as the method of family planning and male participation. The awareness material has been developed to bring forth total sociocultural transformation through development of intense desire, strong determination, effective management and inclusion of a zeal of perpetual efforts both among the promoters and acceptors. The information modules have been developed to suit the requirements of various vehicles through which the message has to be spread. Awareness messages are generated through the inputs from sociocultural, economic, ethical, hygienic and administrative acumen. The materials prepared are disseminated through display hoardings, wall writings, distribution of pamphlets, audiovisual clips, face to face counselling, etc. Communication technology serves mobilising and educating people, especially rural populace. Some steps are suggested to reach remotest villages which are elaborated. Counselling is an essential part of motivation to the client. During the last 5 years a significant surge has been noticed in terms of access to new communication technologies. This may be employed to successfully implement the family planning programme.

No-scalpel vasectomy at a glance

In this article a detailed picture of no-scalpel vasectomy is presented to well-equip the medicos in all the aspects concernmed with the procedure including answers to some often-asked questions by the patients, as far as practicable.

A new look at male sterilisation (no-scalpel vasectomy) in Orissa

The author looks into the comparatively newly introduced procedure of 'no-scalpal vasectomy' as it is practiced in Orissa, compares it with the conventional vasectomy and other methods of sterilisation in terms of advantages and gives the outline of the NSV procedure along with postoperative advice in a brief manner.

Comparison of Marie Stopes scalpel and electrocautery no-scalpel vasectomy techniques

OBJECTIVE

To compare the intra-operative experience and postoperative sequelae between the standard Marie Stopes scalpel vasectomy procedure and electrocautery non-scalpel vasectomy (ENSV) techniques.

DESIGN

Randomised prospective comparative study.

SETTING

Marie Stopes vasectomy centres in the UK.

PARTICIPANTS

A total of 325 men undergoing vasectomy between January and June 1999.

INTERVENTION

Random allocation to the two study arms plus questionnaires at 4 and 14 weeks postoperatively.

MAIN OUTCOME MEASURES

Ease and speed of the procedure; pain levels during and after the procedure; early postoperative complications and time taken to return to work and sexual activity.

RESULTS

The ENSV technique was marginally quicker to perform. Pain levels intra-operatively were comparable. Response rates to the questionnaire were 84.6% and 37% at 4 and 14 weeks, respectively. The ENSV group experienced less pain and bleeding from the wound postoperatively and were quicker to heal. For men who experienced postoperative problems, the time taken to return to work was marginally better in the ENSV group. The time taken to return to sexual activity was marginally faster in the ENSV group.

CONCLUSION

The ENSV procedure appears to be suitable for mass application in locations where electricity is available.

Percutaneous vasectomy: a simple modification eliminates the steep learning curve of no-scalpel vasectomy

PURPOSE

We report a simplified method to avoid the most difficult step of no-scalpel vasectomy, while maintaining its minimally invasive advantages.

MATERIALS AND METHODS

Using the no-scalpel vasectomy instruments in percutaneous fashion we perform vasectomy in the office setting without fixation of the vas to skin using the ring clamp. The sharp no-scalpel hemostat punctures the skin. The vas is then grasped with the ringed instrument instead of piercing the vas and performing the supination maneuver, as described for no-scalpel vasectomy.

RESULTS

Percutaneous vasectomy was performed in 573 men by a single surgeon. In the 35 consecutive cases recently reviewed average operative time was 9.3 minutes with an additional 67 seconds added when a resident performed the procedure on 1 side in 15 cases. As determined by the knuckle of vas pulled through a puncture, average incisional length was 8.4 mm. Patients reported complete recovery in an average of 8.9 days. No major complications occurred. A single case of recanalization (0.17%) was successfully corrected by repeat percutaneous vasectomy.

CONCLUSIONS

Percutaneous vasectomy is a minimally invasive option for permanent male sterilization that avoids the difficult aspects of no-scalpel vasectomy.

The evolution of the Marie Stopes electrocautery no-scalpel vasectomy procedure

OBJECTIVE

To review the evolution of the procedure, the reoperation rate and efficacy data for vasectomies performed in Marie Stopes centres during the periods 1990-1994 and 1995-1999.

DESIGN

Retrospective review of re-operation rates and primary and secondary failures during the periods 1990-1994 and 1995-1999.

SETTING

Marie Stopes vasectomy centres in the UK.

PARTICIPANTS

A total of 41 123 men undergoing vasectomy.

RESULTS

The re-operation rate for the period 1990-1994 was 0.7% and fell to 0.46% for 1995-1999. The reported pregnancy rate fell from 1 in 1429 procedures for the period 1990-1994 to 1 in 2804 for 1995-1999.

CONCLUSION

The results show that vasectomy has had a low failure rate well below that of other methods of birth control. The outcome data continue to improve over time with the evolution of improved techniques and surgical expertise.

Noninvasive vasectomy using a focused ultrasound clip: thermal measurements and simulations

INTRODUCTION

Conventional surgical vasectomy may lead to complications including bleeding, infection, and scrotal pain. Noninvasive transcutaneous delivery of therapeutic focused ultrasound has previously been shown to thermally occlude the vas deferens. However, skin burns and inconsistent vas occlusion have presented complications. This study uses bio-heat transfer simulations and thermocouple measurements to determine the optimal ablation dosimetry for vas occlusion without skin burns.

METHODS

A 2-rad ultrasound transducer mounted on a vasectomy-clip-delivered ultrasound energy at 4 MHz to the canine vas deferens co-located at the focus between the clip jaws. Chilled degassed water was circulated through an attached latex balloon, providing efficient ultrasound coupling into the tissue and active skin cooling to prevent skin burns. Thermocouples placed at the vas, intradermal, and skin surface locations recorded temperatures during ablation. Procedures were performed with transducer acoustic powers of 3-7 W and sonication times of 60-120 s on both the left and right vas deferens (n = 2) in a total of four dogs (precooling control, 3 W/120 s, 5 W/90 s, 7 W/60 s). Measurements were compared with bio-heat transfer simulations modeling the effects of variations in power and sonication time on tissue temperatures and coagulation zones.

RESULTS

Active skin cooling produces a thermal gradient in the tissue during ablation, allowing sufficient thermal doses to be delivered to the vas without skin burns. However, low-power, long-duration heating produced excessive tissue necrosis due to thermal diffusion, while high power and short heating times reduced the therapeutic window and produced skin burns presumably due to direct ultrasound absorption.

CONCLUSIONS

Both simulations and experiments suggest that a therapeutic window exists in which thermal occlusion of the vas may be achieved without the formation of skin burns in the canine model (power = 5-7 W, surface intensity = 1.4-1.9 W/cm2, time = 20-50 s). This range of ablation parameters will help guide future experiments to refine incisionless vasectomy using focused ultrasound.

A minimally invasive vasectomy with the no suture, inline method for vas occlusion

OBJECTIVE

The current vasectomy methods, including the no scalpel vasectomy (NSV), have received considerable attention in recent years, because they are minimally invasive and utilize special instruments to expose the vas. However, at least 28 different methods for vas occlusion have been utilized with these procedures, and some postoperative complications have been attributed to the method of vas occlusion. Therefore, in this report we will critique the existing methods for vas occlusion and introduce a new and rapid method.

PATIENTS AND METHODS

The NSV instruments were used to expose the vas, but, in addition, a fine skin hook, a short-bladed tenotomy scissors, and a hand-held, hotwire cautery were used for the new no suture, inline method of vas occlusion. No ligatures were placed around the vas, no portion of the vas was removed, and the mesentery behind the vas was not disturbed. The vas sheath was disrupted, there was luminal cautery on both the abdominal and testicular sides, a section of vas was detubularized and trimmed, and its epithelium was destroyed by cautery. This technique has been performed in 158 consecutive cases.

RESULTS

All patients have demonstrated complete azoospermia on two follow-up semen analyses, with no pregnancies reported.

CONCLUSION

This new method of vas occlusion seems to be rapid and compatible with the NSV instruments.

No-scalpel vasectomy outside China

Since 1985, the no-scalpel vasectomy technique has been widely used outside China. The prevalence of this technique has helped to increase the acceptability of male sterilization in many parts of the world. More than 5000 physicians in twenty-five developing countries have been trained in the no-scalpel vasectomy technique. In the United States in 1995, nearly one third of vasectomies employed the no-scalpel technique, and in the whole Northern American region, a total of 1100 doctors have been made familiar with the technique. Doctors believe that there are several advantages of the no-scalpel technique, including no incision, no stitches, faster procedure, faster recovery, less chance of bleeding, less discomfort and high efficacy. The key steps of the technique include fixation of the vas and infiltration anaesthesia of the spermatic cord, as well as grasping, delivering and isolating the vas. No-scalpel technique provides a good approach to expose the vas, in conjunction with which, different vas-end occlusion methods may be used.

Vasectomy techniques

Vasectomy can be performed by means of various techniques, although each vasectomy technique requires isolation and division of the vas and operative management of the vasal ends. Removal of at least 15 mm of vas is recommended, although division of the vas without removal of a segment is effective when this technique is combined with other techniques for handling the vasal ends, such as thermal luminal fulguration and proximal fascial interposition. Ligation of the ends without the aid of surgical clips may result in necrosis and sloughing of the ends, which may cause early failure. Leaving the testicular end of the vas open has been shown to be effective and to result in a lower incidence of epididymal congestion and sperm granuloma. The no-scalpel technique offers shorter operating time, less pain and swelling, and faster recovery.

Office procedures. No-scalpel vasectomy

Vasectomy is a safe, permanent, and inexpensive method of surgical sterilization for men. No-scalpel vasectomy is an innovative approach for exposing the vas deferens that is associated with fewer complications than the standard technique of vasectomy (incisional). It has been used in this country since 1986. The no-scalpel vasectomy, preoperative counseling, management of complications, and evaluation of the postvasectomy semen specimen are described.

No-scalpel technique for vasectomy

This review aims to describe the development of the no-scalpel technique and to summarize the available results. An attempt is made to simplify the training of surgeons in the no-scalpel vasectomy technique. This technique uses the method described by Dr Li Shunqiang, utilizing a dedicated vas-grasping forceps; a sharp dedicated dissecting forceps, scissors and sutures are all that are required in addition. In a simple comparative study in Bangkok involving 1203 patients, it was found that the no-scalpel technique was faster. In the 19 cases of complications of symphysis and hemorrhage, 16 occurred using the standard technique (3.1 per 100 patients) and three from the no-scalpel technique (0.4 per 100 patients). The no-scalpel technique is probably more difficult to learn but requires fewer resources. The operation is nearly twice as fast as the standard technique with approximately one-eighth of its complications.

Vas deferens occlusion during no-scalpel vasectomy

The increasing popularity of the no-scalpel vasectomy (NSV) technique in the United States is driven by patient demand for surgical procedures presumed to be less invasive and by the somewhat lower complication rate of the NSV technique. The NSV technique addresses vasal delivery but not vasal occlusion. Intraluminal red-hot wire cautery with sheath closure over the inguinal end of the cut vas (Schmidt's method) has the lowest failure rate of all reasonable vas occlusion methods. The anatomical relationships of scrotal layers can be unclear during the NSV technique. Accurate identification of the sheath layer is critical to sheath interruption if this method of occlusion is to be used. Placement of an absorbable purse-string suture for sheath interruption during the NSV procedure is described. Special attention must be given to placement of one suture bite in the deep (posterior) sheath wall. The vasal occlusion technique described in this paper blends a refined method of vasal delivery (NSV) with the most effective method of vasal occlusion (cautery with sheath interruption).

[No-scalpel vasectomy]

No scalpel vasectomy (NSV) is a new and refined technique with advantages over the conventional incisional technique. It requires no incision, no stitches; it is faster to perform and with less complications, and is equally effective. We present our experience in 100 patients submitted to NSV. The technique is described herein, as well as the anesthetic procedure and the instruments required for NSV.

New matrix material for potential use in "reversible" vasectomy. Preliminary animal biocompatibility studies

The biocompatibility of a new elastomeric-hydrogel matrix biomaterial for use as an intravasal occlusive device was assessed by inserting it into the vas deferens of dogs. The vas was removed and examined histologically after varying periods of time. The biomaterial resulted in total occlusion of the vas. Epithelial changes were limited to squamous metaplasia in areas adjacent to the implant. Changes in the subepithelium were minimal. This new material is biocompatible with the dog vas, and it has potential as an occlusive device for "reversible" vasectomy in men. Semen analysis studies are needed to assess the completeness and reversibility of the vasal occlusion achieved with this implant.

No-scalpel vasectomy: a technique for family physicians

Family physicians frequently perform outpatient vasectomies. A new approach to exposing the vas deferens, called the no-scalpel vasectomy, results in fewer complications and, the authors believe, improved patient acceptance. This technique, which calls for two specialized instruments, is described, along with patient selection and education issues, vasal occlusion techniques and post-vasectomy follow-up.

The Sturgeon Vas Cautery: the first 600 cases

The Sturgeon Vas Cautery, an inexpensive, reusable battery-powered modular unit, has been used in 600 consecutive successful vasectomies with a minimum of complications and without equipment breakdown.

Advances in sterilization equipment

From the array of sterilization procedures that are safe, simple and effective, the service provider must select procedures that fit his or her logistical criteria, which include the cost and maintenance of equipment, availability of supplies, and training of the requisite personnel. In this paper, these criteria are discussed for each of the various sterilization procedures. Information about female sterilization equipment for conventional postpartum laparotomy, minilaparotomy, colpotomy, laparoscopy, and culdoscopy is presented, together with facts about the related tubal occlusion techniques. The standard ligation techniques for male sterilization are compared with the newer electrocoagulation and thermocoagulation methods. A variety of methods for both female and male sterilization that are in the research stage are also mentioned. It is concluded that, from a programmatic point of view, vasectomy and postpartum ligation via laparotomy are the optimal sterilization procedures. For women who have not recently been pregnant, minilaparotomy with a standard tubal ligation technique is recommended, except in large teaching hospitals where laparoscopy can be performed efficiently.

The bipolar needle for vasectomy. I. Experience with the first 1000 cases

A battery-powered, bipolar electrocoagulator has been specifically developed for sealing the cut ends of the divided vas at vasectomy. With a minimum of electric power, the electrocoagulator destroys only the mucosa and one or two muscle cell layers of the vas, which leads to optimal fibrosis of the cut ends. This instrument has been used in more than 1000 vasectomies without a known failure and with a minimum of complications. An analysis of these cases is reported with emphasis upon the method's success in sealing the vas.

An absorbable intravasal stent and a silicone intravasal reversible plug. Report of experiments on animals

The high failure rate of vasovasotomy to restore fertility in vasectomized men prompted this investigation using guinea pigs as the experimental animals. The vasa were divided and absorbable intravasal stents were inserted into the lumens of the vasa at the site of anastomosis. The success or failure to secure patency and reestablish fertility was appraised by histologic sections, vasograms, semen analyses, and breeding tests. A second group of animals had silicone plugs equipped with a detachable central pin placed in both vasa. The design of this procedure was to produce an occlusive azoospermia which might be reversed by removing the central pin. Similar tests were used to establish the effectiveness of this reversible device in producing a temporary sterilization. The procedures were controlled by sham operations and insertion of plugs without pins.

Development of reversible vas deferens occlusive device: IV. Rigid prosthetic devices

Different types of rigid, reversible, vas deferens occlusive devices were developed and evaluated in 14 unilaterally vasectomized dogs. All prosthetic devices had molded silicone rubber bodies, and rigid inflow and outflow tubes. Various techniques for the removal of the vas luminal epithelium, and for the preparation of porous ceramic and etched stainless steel surfaces to encourage tissue ingrowth into the prosthetic device end tubues were attempted. The devices differed in their methods of achieving occlusion. One device used a "rotary stem valve" which had a C-section rotating mechanism; the others used the "shuttle stem valve" which possessed an occlusive element that moved transverse to the axis of flow in the device, thus occluding the device when the stem was depressed. The rotarystem valve was implanted by means of a longitudinal incision. The remaining 13 shuttle stem devices were placed in the vas using either a longitudinal or a transverse implantation. Inno case was sperm transport through the prosthetic devices obtained for more than a few ejaculations.

Development and initial evaluation of a vas deferens valve

In 17 cases of vasectomy, the external diameter of vas deferens was found to be 2.07 +/- .27 mm (Mean +/- S.D.) with a range from 1.7 to 2.8 mm. The internal diameters were 0.93 +/- 0.13 at 5 g and 1.24 +/- 0.16 mm at 100 g insertion force applied to the measuring cone, with lumen ranges from 0.7 to 1.2 and 1.0 to 1.7 mm, respectively. The left-right variations in the same inidividual were of a similar order as between different individuals. Measurements in 6-10 kg rhesus monkeys revealed an internal vas diameter around 0.6 mm with the measuring cone only eased in. At considerably high pressure the vas could be distended to show an internal diameter around 1 mm. The external diameters ranged from 1.5 to 2 mm. Local application to the vas in vivo or in vitro of alpha or beta adrenergic blocking agents, and sodium nitrate had no appreciable effects on the diameters. Three types of valves were developed and tested. The tap-like and the rotary valves were not satisfactorily leak-proof. But the valve with stop-cock mechanism was found to be satisfactory. It was further tested by examining the ejaculate obtained by the method of electro-ejaculation after implanting the valve in the monkey vas. The stop-cock valve is being proposed as a working model for producing reversible vas-occlusion.

Development of reversible vas deferens occlusive device: V. Flexible prosthetic devices

In contrast to the results with rigid-ended prosthetic devices implanted in the vas deferens of the dog, effective sperm transport was obtained for prolonged periods of time with flexible-ended (all soft) devices. Such transport could be halted by device occlusion with clips or shuttle stem valves. Opening the devices resulted once again in the passage of spermatozoa, indicating that these devices may be potentially useful as reversible male contraceptives. More research is necessary to determine the cause of an overall decrease in sperm output after device implantations and to evaluate any adverse side effects of such devices. Dacron velour-covered suture rings on the devices permitted effective tissue ingrowth and prevented leakage or recanalization.