【作者】 陈斌；

【导师】 李森恺； 李强； 周传德；

【作者基本信息】 中国协和医科大学 ， 外科学， 2009， 博士

【摘要】 背景:后尿道狭窄是泌尿外科的难治疾病,治疗手段有尿道扩张,支架植入,内镜下狭窄段切开,开放手术等。其中狭窄段瘢痕切除,无张力下端对端直接吻接术以其治愈率高,复发率低成为后尿道狭窄治疗的金标准。然而仍存在一定比例复发、勃起障碍和尿失禁等并发症,尤其对于复杂型后尿道狭窄。这与会阴部解剖复杂,支配勃起与控尿功能的血管神经束的解剖定位不明确,操作空间狭小,瘢痕组织不能彻底切除有关。为了避免在后尿道重建术中误伤重要的神经血管,减少并发症的发生,彻底切除瘢痕,保证尿道重建后的长期通畅,有必要对前列腺和尿道膜部周围的结构进行解剖定位,以增加手术的安全性;在此基础上进一步改良手术入路,克服传统入路操作空间狭小,瘢痕切除不彻底,尿道重建困难的缺点,提高尿道重建的成功率。本文第一部分是对后尿道手术相关解剖结构的研究,重点是对支配勃起功能的海绵体神经的走行分布,阴部神经的走行分布,与尿流节制相关的尿道括约肌的形态和神经支配进行观测。应用大体解剖,显微解剖,整体解剖与断层解剖相结合的方法对5具福尔马林固定标本和5具新鲜尸体标本进行解剖观察和海绵体神经的定位测量。解剖发现海绵体神经在前列腺尖部位于其后外侧,向下经耻骨前列腺提肌与前列腺之间的间隙穿过,在肛提肌的下方穿过尿生殖膈上筋膜,分向前、向内、向外的分支走行,向前的分支紧邻尿道外括约肌,一部分纤维穿经尿道外括约肌,前行到达阴茎门进入海绵体;后侧部在尿道外括约肌的后方分成细小分支,穿入尿道外括约肌支配尿道外括约肌、尿道海绵体、尿道及尿道球腺;外侧部是细小的横向分支,连接各海绵体神经,阴部神经的各个分支,使海绵体神经与阴部神经之间形成交通。横行向外连接于海绵体神经之间、海绵体神经与阴部神经之间的交通支,与纵向前行的海绵体神经分支、阴部神经分支在尿道腔的后外侧构成一个三角形的网状的结构,位于膜部尿道后外侧。此三角形的网状结构被尿生殖膈上下筋膜包在尿生殖膈内,是尿流节制,阴茎勃起神经穿行的部位,是后尿道手术的危险三角,后尿道手术要避免损伤这个区域的结构。第二部分是在对勃起、尿流节制神经和尿道括约肌解剖定位的基础上,对两个经典的后尿道重建手术入路进行比较解剖学研究,目的是通过解剖比较,明确两个手术入路的适应症;解释临床上无法确定的并发症的发生原因;指导手术操作的安全实施。方法是对3个经过橡胶乳浆灌注的新鲜尸体模拟会阴入路和经耻骨入路,然后进行解剖,观察手术操作路径所涉及的组织结构;测量海绵体神经距中线和膜部尿道的距离:观测可能影响海绵体神经的操作步骤。结果发现,海绵体神经在中线旁5.4±1.7mm,距离膜部尿道7.2±1.1mm;在尿生殖三角的两个底角、两侧边和顶角是支配勃起功能的神经血管走行的部位;球海绵体具有很大的延展性,经耻骨入路的术野比会阴入路宽广。选择手术入路的指针应当是狭窄段的位置,而不是狭窄段的长度,会阴入路适用于球膜部交界处的低位狭窄,经耻骨入路适用于前列腺膜部交界处甚至更高部位的狭窄;勃起功能障碍和尿失禁发生的原因主要是中线操作,中线操作的程度和海绵体神经损伤的可能性呈正相关。第三部分针对会阴入路术野小、操作空间狭窄,瘢痕难以切除彻底的局限性,解剖研究了会阴旁入路的可行性。对2具新鲜尸体模拟会阴入路与改良后的会阴旁入路,观测手术中可能损伤的解剖结构,重点是海绵体神经;对比二者术野的大小,分别观测对尿道膜部和前列腺尖暴露的程度。结果发现会阴旁入路可以从侧方显露尿道膜部,处理膜部到前列腺尖的瘢痕组织,术野为三角形,牵拉下可达到大部分尿生殖三角,操作空间较会阴入路广。会阴旁入路有助于改善术野和彻底切除瘢痕,适用于狭窄位置高,瘢痕严重的情况,对海绵体神经的影响与会阴入路相似。更多还原

【Abstract】 Posterior urethral stricture is a difficult undertaking even in an experienced specialist’s hands.There are many methods for this lesion,such as urethral dilation, urethrotomy,stent implantation and open operation,each of which has its own indications.Anastomostic urethroplasty has been being a gold standard for the treatment of this kind of lesion for its lower recurrence and higher success rate.However there remaining a high incidence of recurrence and some complications,such as erectile dysfunction and incontinence that brings severe damage to the patients especially with so-called complex strictures.Recurrence results mainly from an insufficient scar tissue resection which usually caused by the complex topography of the perineum,ambiguous locatization of the neurovascular buddies and a narrow operating field.It is necessary to shed light of the course and distribution of the neurovascular buddles,especially of the segment from the apex of prostate to the penile hilum for the protective aim in operation. So the incidence of complications might be decreased to some extent,scar tissue could be resected radically and a patent urethra maybe kept for a long term.On the basis of anatomic study,a modified approach will be present which aims to sermount the limitations of the traditional procedures,such as a narrow operating field,ambiguous visualization,insufficient scar resecting and difficulties in urethral reconstruction.Anatomic structures relating to the urethroplasty,especially the course and distribution of the cavernous nerve,pudendal nerves,arteries,the shape and innervation of the rabdosphinctor were investigated by the way of dissection in 5 formalin fixed cadavers and 5 fresh cadavers.The dissection of cavernous nerve was performed under a stereomicroscope by way of cutting the pelvic specimen into a sequential slice.In the first-stage study,we found that the cavernous nerve was posterior and lateral to the apex of prostate,coursed down into the interspace between prostate and levator ani muscle, then was divided into 3 group of branches and coursed vanward,outward and inward respectively.The anterior branches run along the wall of external rabdosphinctor,some branches courses through the wall and go into the hilum of penis.The lateral part of the cavernous nerve branches fine fibers which communicate with the anterior branches of cavernous and pudendal nerves.The posterior branches are posterolateral to the membranous urethra,which innervate the rabdosphinctor,cowper gland and urethra as well.The branches of pudendal nerve and cavernous nerve form a meshwork,which locates at the base angle of perineam.The triangular area of the base angle of perineum is a dangerous field for urethroplasty. On the basis of anatomic study in the first stage,perineal anastomostic urethroplasty and transpubic urethroplasty were imitated on 3 latex-infused fresh cadavers.The aim of the second-stage study is to determine the indications of the two approaches by the way of a comparative dissection,moreover,to interpret the cause of the complications,and provide a guideline for the two operation.Structures within the approaches were obsevered,the distance between cavernous nerve and midline, cavernous nerve and membranous urethra were measured and maneuvers that may be impair the cavernous nerve were detected.The distance between cavernous nerve and midline is 5.4±1.7mm,that of membranous urethra and cavernous nerve is 7.2±1.1mm respectively.Cavernous nerves distribute in the two base and the vertex angle and course along the side line of the urogenital triangle.The bulbspogisum posess good elasticity, and could be stretched for to 4-5cm long.The field of the transpubic approach is wider than that of perineal one.Indications of the two approaches were further verified from an anatomic viewpoint.We recommend that the site while not the legth of a stricture should be taken as the indication for the dission making of which approach should be seclected. The causes of complications were analysed.The incidence of the cavernous nerve injury was correlated to the extent of midline maneuvers.In order to surmount the limitations of the perineal approach that is a narrow eyesight and field,the feasibility of the lateral perineal approach was investigated.We imitated the approaches of perineum and lateral perineum on two fresh cadavers and observed the structures that maybe impaired in the operation,cavernous nerve was the the most emphasized structure in the dissection.We compared the eyesight of the two approaches and the extent of exposure to the membranous urethra and the apex of prostate.The lateral perineal approach could expose and manage the cicartrix tissue more easily from the lateral side of the membranous urethra.The operative field is a triangle and could be enlarged with the aid of traction.The field of maneuver is wider than that of a classic perineal approach and more suited for a prostamembranous stricture with gross scar tissue.The incidence of impairment of cavernous nerve is the same as classic perineal approach.更多还原