Vas deferens, a site of male contraception: an overview

The vas deferens is a site which can be exploited for male contraception without undue side effects. The only ef-fective technique available for male contraception is vasectomy, being practiced world wide, despite that it is a perma-nent surgical procedure and its successful reversal is not assured. Although no-scalpel vasectomy minimizes surgicalprocedures, the fate of its reversal is akin to that of vasectomy. Several occlusive and non-occlusive vasal procedureswhich claim to be reversible without surgical intervention, possess more disadvantages than advantages. Vas occlusionwith plug, ' Shug' or medical grade silicone rubber, although claimed to produce reversible azoospermia without affect-ing spermatogenesis, requires skilled microsurgery for their implantation and later removal. RISUG^R, a non-scleroticpolymer styrene maleic anhydride (SMA), could be more advantageous than vasectomy and other vas occlusive proce-dures in that it could be a totally non-invasive procedure by 'no-scalpel injection' and 'non-invasive reversal'. It isclaimed to offer long-term contraception without adverse side effects and also to be possible as a male spacing methodby repeated vas occlusion and non-invasive reversal. The drug is currently under multicentre Phase Ⅲ clinical trial.

Histological study of vas deferens following intravasallaser irradiation

<abstract>Aim: To study the histologic changes of the vas deferens following Nd: YAG laser irradiation. Methods: Intravasal laser irradiation was given to (i) 52 segments of rabbit (laser dosage: 2 seconds at 40 W-50 W) and 16 segments of human (3 seconds at 45 W-55 W) vas deferens in vitro, (ii) 25 rabbit vasa (2 seconds-2.5 seconds at 40 W-45 W) in vivo and (iii) 2 human vasa (3 seconds at 55W) in vivo. Segments of vasa were removed from the in vivo irradiated vasa deferentia 15 days-180 days (rabbit) or 15 days (man) after the exposure. All vas segments were embedded in methacrylate resin. Serial sections (thickness 25μm-30μm) were obtained and observed under a light microscope. Results: (i) Laser-induced damage reached the muscularis layer in 27 % and 94 % of the rabbit and human vas segments in vitro, respectively, (ii) Fourteen of the 25 in vivo rabbit vasa were completely occluded by fibrous tissue and the longer the time interval after treatment, the more likely was the vas occluded. Those unoccluded vasa had either a normal histology or a mucosal damage, (iii) One in vivo human vas was almost completely occluded by the fibrous tissue but the other had a relatively large lumen packed with sperm granulomatous tissue and partial destruction of the smooth muscle layer. Conclusion: Laser irradiation can induce long-term vas occlusion; for rapid occlusion, laser doses just completely destroying the mucosal layer will be advisable.

Non-invasive reversal of intraluminal vas deferens polymer injection-induced azoospermia——technology

Aim: The rationale and technique underlying a novel concept of non-invasive removal of an intravasal vas deferens poly-meric contraceptive drug to reverse drag injection-induced azoospermia are explained. Thus the conventional methods ofsurgical exploration to remove vas deferens plugs and intravasal injection of solvents to flush out contraceptive drugs are tobe replaced by steps which will be readily accepted by subjects. Methods: The approach is based upon the non-invasiveapplication of specific forces to various segments of the vas deferens so that non-sclerosing and non-tissue-adherent com-pounds, in particular styrene maleic anhydride (SMA) can be expelled. Forces are generated by palpation; percuta-neous electrical stimulation; vibration application; and percussion. The forces help to propel the intravasal polymer to-wards the ejaculatory duct for expulsion during ejaculation. All aspects of the total technique are clinically acceptable,simple, atraumatic, unlikely to cause pain and discomfort even without tranquilizers, local or general anaesthetics. Theprocedure may be repeated several times in different sittings spaced apart by about one week to achieve adequate plug ex-pulsion. Results: Model experiments demonstrated the feasibility of the concept. The polymer was nonadherent andcould be moved within the vas deferens by the application of specific forces. Sufficient removal was possible to enablespermatic fluid to be transported along a region previously occupied by the polymer. A corroborating subhuman primatestudy by an independent investigator has shown that the semen profile becomes normal following the reversal. Conclu-sion: Adoption of the new technique may provide a means of non surgical restoration of normal semen profile after a pe-riod of fertility control obtained by intravasal drag injection. (Asian J Androl 1999 Sep ; 1: 131 - 134)

Vasectomy by epithelial curettage without suture or cautery： a pilot study in humans

Curettage of the epithelium of the vas deferens might be a safe and effective method of male sterilization. We conducted a pilot study of vasectomy by epithelial curettage with a novel microcurette called the Vas-X in 12 normal men requesting elective sterilization. Seminal fluid analysis was obtained monthly after the procedure for 6 months. Pain was assessed by questionnaire. Three months after the procedure, all men attained sperm concentrations of less than 0.2 million sperm per mL, and seven were azoospermic. Post-procedural pain was minimal. Nine men ultimately achieved and maintained azoospermia; however, 4 to 6 months after the procedure, sperm concentrations increased in three of the 12 subjects, necessitating repeat vasectomy. Microscopic examination of the vas deferens from these failures revealed re-canalization. Vasectomy by epithelial curettage can result in effective sterilization; however, 1/4 of the subjects were not effectively sterilized by the procedure due to re-canalization of the vas deferens. Epithelial curettage will require further refinement to determine if it is a viable form of vasectomy.

Prospective Comparative Study of Human Vas Occlusion with Chinese and Netherlandish Medical Materials

To find a new uas occlusive material and verily the efficacy of Zhao's traditional uas occlusion with medical polyurethane(MP),we used the aPProved medical silicone rubber (MSR) made in the Netherlands,for a prospective study in comparison with the contraceptive effect of these two materials.We adopted the standardized MPU uas occlusion method to 13subjects and the unified MSR uas occlusion method to 11 subjects. All subjects received semen analysis and related physical examination before the operation,and semen analysis and complication examination in the 3th, 6th and 12th months alter operation. Neither of groups had complication and notable uncomfortable symptoms following operation. The sperm disaPPearance rate in MPU group was 92.31%(12/13) while in MSR group, only one patient's sperm disaPPeared 3 moths after operation.During the other postoperative follow up periods all operated patients had spermatozoa allhough the sperm density decreased obviously and indicated partial vas occlusion.These results indicate that the MPU vas occlusion has a good sterilization elject,but the MSR has not.

70例无精子症生精细胞检出与病因分析

目的:根据精液中生精细胞的有无、形态和比例,进行精象分析,作为评价睾丸功能和鉴别阻塞性和非阻塞性无精子症的有效方法。方法:用精液涂片,瑞-吉氏染色,油镜下分类和分型,并以睾丸活检病理所见对照。结果:697例不育者中发现70例无精子,检出率为10.04%,有生精细胞者42例(60%),95.2%有精母细胞和精子细胞;无生精细胞者28例(40%),两者的睾丸大小显著不同。病因以服用过棉籽油占30.00%;原因不明占22.86%;腮腺炎史占12.8 6%;输精管因素占10.00%。精液细胞学检查与睾丸活检病理诊断基本一致。结论: 精液细胞学检查是一种无创伤性、无后遗症、无痛苦和操作简便,适用于基层判断睾丸功能和区别病因的有效的方法,值得推广。

激光输精管凝堵模型的研究

本研究旨在建立激光输精管凝堵模型,为进一步研究输精管光凝术提供依据。对160只家兔及9例人离体输精管,分3组进行不同照射功率和时间的光凝术试验,术后经病理检查确定有效凝堵,最终得出达到阈损伤的最佳激光功率及照射时间。结果:光凝术阈损伤值家兔为40W/0.5～1s,人离体输精管为45W/1s或50W/0.5s。本研究提示高功率YAG激光亦可用于光凝术。输精管光凝术的有效凝堵阈损伤为热凝固达到中环肌层。

精浆内抗精子抗体和免疫复合物的研究——对男性不育患者及输精管粘堵术者的观察

本文用ELISA法研究了174名男性不育患者及43名输精管粘堵术后精浆中的抗精子抗体及其种类。结果表明,精浆中抗精子抗体的检出率,在男性不育患者中为24.1%,输精管粘堵术后者为48.8%。在这些患者的精浆中可检出IgA、IgG和IgM型抗精子抗体,其中主要是IgA。同组人群血清和精浆中的抗精子抗体缺乏相关性。精浆中抗精子抗体的存在与精子活动率的下降有一定的关系。应用PEG法测定精浆中免疫复合物,在66例精子抗体阳性的患者中,阳性率为56.1%,表明局部抗精子的自身免疫反应,在一定条件下可导致免疫复合物的形成。

输精管解剖参数测量与单位长度输精管破裂容量的相关性研究

本研究应用计算机图像分析技术，测量取自１０７例男性２１０根输精管直径，结果平均等效圆外径为２．１７±０．２０ｍｍ，等效圆内径为０．５６±０．０８ｍｍ，管壁厚０．８１±０．２１ｍｍ。测量１２４根１ｃｍ长输精管在被动扩张条件下的破裂容量平均为０．０５±０．００７ｍｌ。对破裂输精管的组织形态学进行了观察，并对破裂容量与个体特征及输精管解剖参数的相关性进行了分析和探讨。本研究结果为输精管阻塞节育法提供了具有实用参考价值的数据和资料。

中国男性输精管节育术研究与现状

目前男性可采用的有效控制生育的方法仅有性交中断、阴茎套和输精管绝育术。最近三十多年来,为提高避孕成功率,减少并发症,中国学者对输精管切除术进行了许多创造性的改进。根据其节育机制分为阻塞性与非阻塞性输精管节育术。现在非常迫切需要发展安全、有效、可逆的男性避孕方法。在目前研究的所有男性避孕措施中,新的外科节育方法最接近临床应用。

输精管金属环可复性节育术的酶细胞化学研究及电镜观察

用酶细胞化学方法结合超微结构，观察了家兔输精管经金属环夹及加不同性质支撑物后输精管碱性磷酸酶（ＡＫＰ），睾丸乳酸脱氢酶（ＬＤＨ）的活性变化及输精管、睾丸和附睾的超微结构改变，在细胞学基础上，探讨了输精管金属环可复性节育术的影响因素，并结合酶活性变化，分析了其复通后复孕率较低的原因。

家兔输精管激光凝堵术可复性研究

目的:了解家兔输精管激光凝堵术(光凝术)的效果及可复性。方法:应用Nd:YAG激光器,经套管针穿刺家兔输精管,导入激光光纤照射凝堵试验,确定了有效激光凝堵阈值,对光凝术后60只家兔的凝堵效果进行了一年的动态观察,并对输精管凝堵段结节作了穿刺再通试验。结果:家兔精子消失率100％,穿刺再通率72.7％。结论:高功率激光亦可用于光凝术,达到光凝效果的阈损伤值为40W/1s,输精管病理阈损伤为中环肌层。本文提示光凝术较传统结扎术简单、创伤小、并发症少、可复性强。

52例绝育术后类神经症的临床分析

52例绝育手术后类神经症患者,75%在术前有不同程度的精神顾虑和抵触情绪,几乎全部病例(94.2%)在手术时情绪紧张,半数以上患者的个性属内向性格。以癔症居多(50%),次为神经衰弱(26.9%),其它各亚型均见发生。提示术前加强科普教育,消除精神紧张等心理因素,严格选择绝育手术对象,是预防和减少本症发生的一项重要措施。

输精管可复性栓堵术后精浆肉毒碱含量的改变

本文测定了输精管可复性栓堵术（简称栓堵术）后精浆肉毒碱含量。精浆肉毒碱作为附睾的功能性指标早已被人们确认。肉毒碱是在微量酶反应系统下测定的。结果显示：栓堵术后随着时间的延长精子完全消失率增加；栓堵术前精浆肉毒碱浓度平均为３３６．９±７８．１ｎｍｏｌ／ｍｌ（ｘ±ｓｎ＝５８），栓堵术后精子完全消失者和未完全消失者精浆肉毒碱浓度分别为１１２．７±５０．７ｎｍｏｌ／ｍｌ和１７２．５±７１．７ｎｍｏｌ／ｍｌ，明显低于栓堵术前（ｎ＝１７２和ｎ＝５１，Ｐ＜０．０１），精子完全消失者精浆肉毒碱浓度比未完全消失者明显降低（Ｐ＜０．０１）。栓堵术后有３例精液常规检查精子计数＞２．０×１０６／ｍｌ，精浆肉毒碱含量都在正常范围（术前）内。提示栓堵术后附睾分泌产生的物质有可能渗透到精液中抑或通过栓子与输精管壁间的空隙流出，栓堵术后精浆肉毒碱的含量可作为判定输精管栓堵是否完全或成功的一个辅助指标。

可复性输精管激光凝堵法研究

应用Ｎｄ：ＹＡＧ激光机，将激光光纤插入家兔输精管照射凝堵，３０只家兔输精管完全堵塞。５只家兔凝堵段输精管穿刺复通试验，２只再通成功。进而对人离体输精管段进行激光凝堵试验，经病理检查，确定了有效凝堵绝育阈值。在此基础上对１５例自愿节育者，经皮穿刺输精管导入激光光纤，进行激光凝堵节育。随访二年以上，１４例精子消灭。

输精管可复性注射栓堵术阻塞机制剖析

为闸明输精管可复性注射栓堵术的阻塞机制，对２９例受术者采用不同的栓堵剂量，术后切下栓堵段输精管进行观察；２例（２侧）输精管，直视下注入栓堵剂，手术显微镜下观察破裂部位；１２例术后１～２年受术者取栓观察。结果：栓堵剂量在０．０８～０２０ｍｌ范围内，输精管全部破裂，破裂部位是在阻断器钳夹处。表明栓堵剂并不是在输精管腔内膨胀形成栓子阻断精子通路，而是通过一种“软环阻塞机制”阻断输精管。提出被栓子包绕输精管的坏死、液化是术后再通的原因之一，也是在栓子周围形成精液囊肿的主要原因。

聚氨酯栓堵局部输精管的形态学观察

对４例输精管注射聚醚型聚氨酯弹性体（ＭＰＵ）栓堵（简称输精管ＭＰＵ栓堵）术后立即切除的栓堵段输精管和１０例输精管ＭＰＵ栓堵术后４年因子女意外或并发症行手术治疗所切除的栓堵段输精管．进行病理形态学观察。结果显示栓堵段输精管全部破裂，大部分ＭＰＵ由破口逸出包裹输精管，管腔内仅存少量ＭＰＵ，术后４年栓堵段输精管管壁不同程度退行性变和纤维组织增生，并伴有玻璃样变和灶性吞噬细胞浸润，栓子两端管腔闭塞。并发痛性结节４例有精了肉芽肿、异物肉芽肿形成，伴神经纤维增生和局部淋巴细胞浸润。并对输精管ＭＰＵ栓堵的机理和手术合并症进行了讨论。

输精管畅通型铜栓节育术的实验研究

我们将粒度４０～６０μｍ铜粉（９９．５％）、氯化钠（９９．８％）各５０ｍｇ与栓堵剂ＭＰＵ０．０６ｍｌ混匀后注入兔输精管并保持管腔通畅；该铜栓体外释放测定１．９３５μｇ／ｄ，其铜离子浓度可使离体精子在３～６小时达完全制动。经对２５只家兔注射后３０、９０、１８０、２７０、３６０天观察，输精管腔内铜栓通道通畅率分别为１００％、４４％、３２％、１２％、４％，活精子率分别为１５．３％、１０．５％、９．７％、０％、０％，合笼试验雌兔均未受孕。提示：在通道堵塞前铜栓释放的铜离子可使精子活力、活率明显下降，死精子及断头率明显上升，达节育水平；

输精管结扎术四种不同残端处理与节育效果的比较性研究

８１６例自愿接受输精管绝育术男子按照节育手术常规施行输精管结扎术，受术者随机均分为４个队列，分别施行不同的输精管残端处理方法：（１）单纯两断端结扎；（２）结扎加精索筋膜隔离；（３）结扎加苯酚涂灼；（４）电灼。术中以１：３０００新洁尔灭溶液每侧输精管５ｍｌ行精囊灌注，术后３年４种方法精子消失率分别为９０．０％（１８０／２００），９４．１％（１７５／１８６），９３．７％（１７９／１９１）及９４．５％（１７２／１８２），术后并发症为０．４％（３／８１６）。在此对输精管结扎术后自发再通问题进行了讨论，并认为１：３０００新洁尔灭溶液行精囊灌注是安全可行的。

氩离子激光凝堵输精管后睾丸附睾的形态学观察

对氩离子（Ａｒ＋）激光凝堵输精管后不同时期的睾丸和附睾做了形态学观察，发现在术后半月，无论在肉眼和镜下睾丸和附睾均无明显变化；术后１个月，附睾出现淤积现象；２～３个月后，睾丸肉眼形态无明显改变，镜下睾丸部分曲细精管生精细胞萎缩，肉眼观附睾体积增大，镜下输出小管和附睾管扩张，个别标本间质内有精子性肉芽肿形成；术后６个月或更长时间，睾丸和附睾的变化基本同前。提示氩离子激光凝堵输精管后，部分睾丸生精细胞萎缩并附睾精子肉芽肿形成是影响复孕的两个因素。