Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Vas Occlusion”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1983

Sterilization by vas occlusion without transection does not reduce postvasectomy sperm-agglutinating antibodies in serum. A randomized trial of vas occlusion versus vasectomy.

The influence of transection of the vasa on the increase in sperm-agglutinating activity in serum after vasectomy was investigated in a prospective randomized study. Sixty-eight males requesting vasectomy were allocated to either of two groups: vas occlusion by tantalum clips without transection of the vasa, or conventional vasectomy by transection and ligation. Sperm-agglutinating antibodies were determined by a micro-agglutination test before and 6 months after vasectomy or vas occlusion. A significant increase in sperm-agglutinating activity in serum after sterilization was found in both groups, but there was no intergroup difference.

Adult↗
PubMedDate not supplied

Status of spermatogenesis and sperm parameters in langur monkeys following long-term vas occlusion with styrene maleic anhydride.

Vas occlusion by styrene maleic anhydride (SMA), trade name RISUG (one of the promising male contraceptive procedures currently in phase III clinical trials), at 60 mg/vas deferens dissolved in 120 micro L dimethyl sulphoxide (DMSO) at up to a 540-day study period caused severe oligospermia in the first 2 to 3 ejaculations and uniform azoospermia in the subsequent ejaculations without toxicity in langur monkeys. The ejaculated spermatozoa were necroasthenoteratozoospermic, suggesting instant sterility. Routine hematology and clinical chemistry parameters and the serum testosterone and sperm antibody titers remained unchanged from their pretreatment values until 540 days vas occlusion. Histology of testes revealed continued spermatogenesis throughout the study period. The stages of spermatogenesis appeared normal until 300 days of vas occlusion. At 360 days of vas occlusion, germ cells appeared in the lumen. Degeneration of seminiferous epithelium was evident in some of the tubules. Following 420 days of vas occlusion, the central portion of the testis showed regressed seminiferous tubules depicting various shapes and devoid of germ cells, which continued until 540 days of vas occlusion. Ultrastructure of the testes after 540 days of vas occlusion revealed vacuolization in the cytoplasm of Sertoli cells and degenerative features in the membranes of the spermatocytes and spermatids in the affected seminiferous tubules. The sub-cellular features of the normal tubules were similar to those of controls. The results suggest focal degeneration of seminiferous epithelium in the central portion of the testis following long-term vas occlusion with SMA.

Animals↗
PubMed1995

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

This paper describes two consecutive studies: a volume study and an efficacy study. The volume study determined the appropriated volume of Medical Grade Silicone Rubber (MSR) needed to achieve complete occlusion of the vas deferens. This was done by in-vitro testing of 130 human vas specimens containing plugs of MSR formed in vivo. The volume of MSR needed to occlude the vas was 0.1531 +/- 0.0059 ml injected by five to six turns of the applicator handwheel. There was a correlation between MSR volume, weight, and the number of turns of the applicator handwheel. An influence of body height upon the volume and weight of the MSR was also observed. An oval shaped clamp (15 mm long) was more effective in producing secure vas occlusion than was a round clamp (10 mm long). The mean outer diameter of the vas specimens was 1.80 +/0 0.15 mm, and the mean maximum dilated inner diameter was 0.93 +/- 0.11 mm. The efficacy study was a clinical trial to compare MSR was occlusion (using an oval 15 mm clamp and the appropriate volume derived from the volume study, n = 58) with no-scalpel vasectomy as the standard procedure (n = 64). The azoospermia rate following MSR vas occlusion was not significantly different from that following no-scalpel vasectomy, and was achieved in 3-6 months.

Biocompatible Materials↗
PubMed2000

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.

Follow-Up Studies↗
PubMed1998

Ultrastructural changes in the spermatozoa of langur monkeys Presbytis entellus entellus after vas occlusion with styrene maleic anhydride.

Changes in the physical characteristics of semen and ultrastructure of the spermatozoa of langur monkeys after vas occlusion with styrene maleic anhydride (SMA), a polymer with pH-lowering action, are reported. Vas occlusion resulted in severe reversible hypospermia. Severe oligospermia was observed in the majority of animals (five of eight) in the first ejaculation, 30 days after vas occlusion, and in two animals in the second ejaculation, 60 days after vas occlusion. Subsequent monthly ejaculations for 5 months revealed uniform azoospermia. The voided spermatozoa were immotile and supravital staining confirmed necrospermia. Scanning electron microscopy (SEM) revealed severe coiling of tail, rupture of acrosomal envelope, and bent midpiece associated with damaged mitochondrial sheath. Observations by transmission electron microscopy (TEM) revealed vacuolization in the nucleus, membrane damage in the acrosome, loss of segmented columns, and numeric aberrations in the centriole of the neck, as well as degeneration of mitochondrial sheath and axoneme in the midpiece, and absence of outer plasma membrane in the midpiece and tail. The results indicate that the necrospermic status of the spermatozoa during initial ejaculations may offer instant sterility after vas occlusion with SMA.

Animals↗
PubMedDate not supplied

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.

Evaluation Studies as Topic↗
PubMed2005

Preclinical evaluation for noninvasive reversal following long-term vas occlusion with styrene maleic anhydride in langur monkeys.

A preclinical evaluation for reversal through a noninvasive approach following long-term vas occlusion with styrene maleic anhydride (SMA) has been attempted in langur monkeys at the level of semen parameters, sperm functional tests, semen biochemistry, histology and ultrastructure of reproductive organs, hematology and serum clinical biochemistry including antisperm antibodies (ASA), prostate-specific antigen (PSA) and testosterone. Noninvasive reversal through palpation, percutaneous squeezing and electrical stimulation, forced vibratory movements and suprapubic percussion in the inguinal segments and per-rectal digital massage was attempted in seven langur monkeys after 540 days following vas occlusion. The results revealed instant azoospermia reversal on the same day of reversal with impaired sperm quality, which showed gradual improvement and normospermia with normal motility and viability after 60-90 days of reversal. Sperm functional tests, including ultrastructure of spermatozoa, indicative of sterility in the initial ejaculations, reached normalcy after 90-120 days of reversal. The seminal plasma biochemistry indicative of obstructive azoospermia regained a normal pattern after 90-120 days of reversal. The morphology of testes that showed focal degeneration during 540 days of vas occlusion and that of vasa deferentia that showed exfoliation of epithelial cells resumed to normal morphology comparable with control animals after 150 days of reversal. The morphology of the epididymis, seminal vesicle and prostate did not show appreciable changes following vas occlusion and after noninvasive reversal compared with those of control animals. Hematology, serum clinical chemistry, ASA, PSA and testosterone fluctuated within control limits, indicating safety of the procedure at the level of accessory reproductive organs. The results suggest that noninvasive reversal is feasible even after long-term vas occlusion with SMA and is safe without adverse side effects.

Animals↗
PubMed1999

Ultrastructural changes in the vas deferens of langur monkeys Presbytis entellus entellus after vas occlusion with styrene maleic anhydride and after its reversal.

Ultrastructural changes in the vas deferens of langur monkeys after 150 days of vas occlusion with styrene maleic anhydride (SMA) and after 150 days of noninvasive reversal are reported. The vas deferens of the sham-operated control animals revealed active secretory and absorptive functions. The basal cells showed prominent nucleus and sparse cytoplasmic organelles, and the principal cells characterized by oval or irregular nucleus, well developed mitochondria, Golgi bodies, rough endoplasmic reticulum, secretory granules in the Golgi area, free ribosomes, and glycogen granules in the supranuclear region suggesting secretory function. Vesicles and stereocilia in the apex region suggested absorptive functions of the vas deferens. Vas occlusion by SMA resulted in exfoliation of epithelial cells, pyknotic nuclei, and vacuolated cytoplasm virtually devoid of cytoplasmic organelles and stereocilia. After noninvasive reversal, the vas epithelium regained a state of normalcy as evidenced by prominent plasma membrane, nucleus, cytoplasmic organelles, and stereocilia. The results suggest that the exfoliation of the epithelium due to vas occlusion by SMA regains normalcy after 150 days of noninvasive reversal.

Animals↗
PubMed2005

Safety evaluation of long-term vas occlusion with styrene maleic anhydride and its non-invasive reversal on accessory reproductive organs in langurs.

AIM: To evaluate the safety of the long term vas occlusion with styrene maleic anhydride (SMA) and its non-invasive reversal at the level of accessory reproductive glands ARGs in langurs. METHODS: The morphology of seminal vesicle and ventral prostate was evaluated by light as well as transmission electron microscopy. Serum clinical chemistry and urine albumin were evaluated in an autoanalyzer using reagent kits. Fructose, acid phosphatase and zinc in the seminal plasma were evaluated spectrophotometrically according to the WHO manual. Serum testosterone, prostate specific antigen and sperm antibodies were evaluated by enzyme-linked immunosorbent assays (ELISA) using reagent kits and hematology was estimated according to standard procedures. RESULTS: The morphological features and secretory activity of the seminal vesicle and prostate were normal as evidenced by the presence of well-developed mitochondria, rough endoplasmic reticulum, Golgi bodies, secretory granules and normal nuclear characteristics throughout the course of investigation. Serum testosterone and prostate specific antigen remained unaltered and serum antisperm antibodies level presented negative titres. Urine albumin was nil. Total red blood corpuscles (RBC), white blood corpuscles (WBC), hemoglobin (Hb) and red cell indices, serum protein, glucose, cholesterol, creatinine, creatine kinase (CK), serum glutamate oxalate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), lactate dehydrogenase (LDH), bilirubin, urea, triglycerides and high-density lipoprotein (HDL) did not show appreciable changes following vas occlusion and after its non-invasive reversal. Although fructose, acid phosphatase (ACP) and zinc in the seminal plasma showed a significant reduction following vas occlusion, it could not be related to the morphology of seminal vesicle and prostate. CONCLUSION: SMA vas occlusion and its non-invasive reversal do not damage the accessory reproductive organs.

Anhydrides↗
PubMed2000

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.

Animals↗
PubMed1977

Vas occlusion by tantalum clips and its comparison with conventional vasectomy in man: reliability, reversibility, and complications.

Occlusion of the vas deferens has been carried out by applying tantalum clips in 60 men. Another 50 men were vasectomized conventionally and served as controls. Vasography showed that two clips were required on each vas to bring about perfect and firm occlusion. The incidence of postoperative infection and other complications was much lower in the clip-occluded cases. Under a long-term follow-up, 10% of the conventionally vasectomized men were dissatisfied with the operation as compared with 2% of the clip-occluded group. Both groups became azoospermic within 3 months and the failure rate was zero. Removal of the clips not only was difficult but left the vas compressed and leaking. The method cannot, therefore, be considered reversible by itself. However, recanalization could easily be achieved by end-to-end anastomosis after excision of the small clipped segment or by side-to-side anastomosis without any excision. This, damage to the neuromuscular apparatus of the vas may be minimized. Male sterilization by clip occlusion has the advantages of minimal surgical intervention, shorter operative time, safety from postoperative infection, and easier recanalization if desired.

Evaluation Studies as Topic↗
PubMed2004

A comparison of vas occlusion techniques: cautery more effective than ligation and excision with fascial interposition.

BACKGROUND: Vasectomy techniques have been the subject of relatively few rigorous studies. The objective of this analysis was to compare the effectiveness of two techniques for vas occlusion: intraluminal cautery versus ligation and excision with fascial interposition. More specifically, we aimed to compare early failure rates, sperm concentrations, and time to success between the two techniques. METHODS: We compared semen analysis data from men following vasectomy using two occlusion techniques. Data on intraluminal cautery came from a prospective observational study conducted at four sites. Data on ligation and excision with fascial interposition came from a multicenter randomized controlled trial that evaluated the efficacy of ligation and excision with versus without fascial interposition. The surgical techniques used in the fascial interposition study were standardized. The surgeons in the cautery study used their customary techniques, which varied among sites in terms of type of cautery, use of fascial interposition, excision of a short segment of the vas, and use of an open-ended technique. Men in both studies had semen analyses two weeks after vasectomy and then approximately every four weeks. The two outcome measures for the analyses presented here are (a) time to success, defined as severe oligozoospermia, or <100,000 sperm/mL in two consecutive semen analyses; and (b) early vasectomy failure, defined as >10 million sperm/mL at week 12 or later. RESULTS: Vasectomy with cautery was associated with a significantly more rapid progression to severe oligozoospermia and with significantly fewer early failures (1% versus 5%). CONCLUSION: The use of cautery improves vasectomy outcomes. Limitations of this comparison include (a) the variety of surgical techniques in the cautery study and differences in methods of fascial interposition between the two studies, (b) the uncertain correlation between sperm concentrations after vasectomy and the risk of pregnancy, and (c) the use of historical controls and different study sites.

Cautery↗
PubMed1984

Vasovasostomy in rabbits after vasectomy or vas occlusion by tantalum clip.

Vasovasostomy was performed in rabbits that had been vasectomized or had the vas occluded by a tantalum clip for 6 or 15 months. Vasovasostomy restored fertility to 40-50% in vasectomized rabbits and 60-70% in the tantalum clip-occluded animals. Any changes that occurred due to vasectomy and tantalum clip occlusion (e.g. testicular weight, enzyme concentrations in the testis) returned to normal within 3-6 months of vasovasostomy. We suggest that vas occlusion with tantalum clips is a good method of surgical male sterilization and has a high success rate for restoration of fertility.

Alkaline Phosphatase↗