Colour Doppler ultrasonography of female urethral vascularization in normal young volunteers: a preliminary report

OBJECTIVE: To assess urethral vascularization in healthy young women, using colour Doppler ultrasonography. SUBJECTS AND METHODS: Eleven healthy young women volunteers (mean age 33.6 years, range 24-46) with no pelvic floor disorders and no history of incontinence were assessed. The subjects underwent colour Doppler ultrasonography using a 4-7 MHz convex broadband transducer. Translabial sagittal scans of the urethra were taken when the subjects had a full bladder, both during the oestrogenic and progestogenic phases. The colour Doppler ultrasonography parameters were optimized to detect slow flows in the anterior and posterior distal, middle and proximal urethra. A rank-sum nonparametric test was used to assess differences between the resistive indices. RESULTS: The statistical evaluation showed a significant difference in the resistive index only in the anterior urethra, between the distal and middle plus proximal urethra, in both the progestogenic (P = 0.002) and oestrogenic (P = 0.0127) phases. CONCLUSIONS: This study confirmed that the vascularization of the urethra plays an important role in the 'seal' effect, which is considered one of the most important factors in urethral closure. There was a significantly greater resistive index in the anterior proximal urethra than in the middle and distal urethra. These findings suggest that the seal effect is related to the existence of a rich venous urethral vascularization, involved in the mechanism of urethral closure. Colour Doppler ultrasonography of the urethra seems to be feasible and useful for understanding the mechanism of the vascular component in female continence.     

男性盆丛解剖标志在下尿路手术中的意义

为探寻下尿路手术中避免损伤盆丛的解剖标志，对１０个盆腔器官标本作盆丛大体解剖或大切片，观察盆丛与盆腔器官的毗邻关系，结果表明，盆丛位于直肠的前外侧，精囊腺的后外侧，在前列腺基底部与前列腺外侧的血管形成神经血管束，于尿道感染部的外侧和后外仙穿过尿生殖膈，认为精囊腺和神经血管束可作为下尿路术中避免损伤盆丛的解剖标志，文中还对盆丛的解剖分布及其与医源性阳萎的关系进行了讨论。     

Anatomy of the posterior urethra]

The short section of the urethra that passes through the urogenital diaphragm is termed the membranous urethra. It is accompanied by several vessels and nerve fibers. In surgery on the membranous urethra the perineal body is of crucial importance, and precise knowledge of the course of the urethra through the pelvic floor is essential. Furthermore, the relationship between the membranous urethra and its accompanying structures is of great importance. These include the branches of the internal pudendal artery, the prostatic venous plexus and the cavernous nerves coursing ventrally from the pelvic plexus. The nerves supplying the membranous urethra were studied in fetuses with the help of a magnifying lens. The results of the dissections are documented by histological sections, photographs and paintings.     

Precise localization of the autonomic nerves from the pelvic plexus to the corpora cavernosa: a detailed anatomical study of the adult male pelvis

The anatomical location of the branches of the pelvic plexus that innervate the corpora cavernosa has been identified previously in stillborn male neonates and fetuses. Based upon these observations, the techniques of radical retropubic prostatectomy and cystectomy have been modified to avoid injury to the autonomic innervation of the corpora cavernosa. However, the exact anatomical relationships of these nerves to the prostate, urethra and other pelvic structures in adults are unclear, since the initial anatomical studies of the pelvic plexus were performed in stillborn neonates in whom the accompanying vessels and fascia had been removed. Because these nerves are microscopic in size and can only be identified by their association with other pelvic structures, it was believed that a more refined understanding of the anatomy was necessary. In an effort to identify precisely the relationship of the cavernous branches of the pelvic plexus to the lateral pelvic fascia and the branches of the prostatovesicular arteries and veins, the following study was performed. Shortly after death a 60-year-old man was perfused completely with Bouin's fixative solution. The entire bladder, prostate, urethra, penis, corpora cavernosa, rectum, and pelvic sidewall fascia and musculature were removed en bloc. The specimen was serially sectioned transversely at 10 mu thickness, and every tenth section was stained with hematoxylin and eosin. An anatomical reconstruction in 3 dimensions was performed and illustrated. Thus, the specific location of the nerves that innervate the corpora cavernosa and their important relationships to the urethra, prostatic capsule, Denonvilliers' fascia and pelvic floor vasculature have been identified.     

NADPH-diaphorase in glandular cells and nerves and its relation to acetylcholinesterase-positive nerves in the male reproductive tract of man and guinea-pig

The presence of NADPH-diaphorase activity and acetylcholinesterase in the testis, epididymis, vas deferens, seminal vesicle, pelvic plexus, prostate and urethra of man and guinea-pig was investigated with the nitro blue NADPH technique and the thiocholine method, respectively. In human material NADPH-diaphorase activity was found in the Leydig cells, Sertoli cells and the epithelial linings of the rete testis, the excretory ducts, seminal vesicle, prostate and urethra. The guinea-pig material showed staining of the Leydig cells and spermatozoa and similar epithelial staining of the tract as man. Nerves beneath the epithelium and in the muscle layers of cauda epididymis, vas deferens, seminal vesicle, prostate and urethra were also stained. NADPH-diaphorase-positive nerve cells were seen in the pelvic plexus. Some cells also displayed acetylcholinesterase activity but others showed activity for only one of the enzymes or no activity for either enzyme. In the cauda epididymis, vas deferens, seminal vesicle, prostate and urethra acetylcholinesterase-positive nerve fibres formed a plexus beneath the secretory cells. It is concluded that NADPH-diaphorase, generally accepted as a nitric oxide synthase, is present in glandular cells of the male genital tract. The enzyme is also present in nerves, where it is partly co-localized with acetylcholinesterase. Received: 15 January 1997 / Accepted: 18 September 1997     

Increased proximal urethral sensory threshold after radical pelvic surgery in women

AIM: To identify factors that potentially influence urethral sensitivity in women. PATIENTS AND METHODS: The current perception threshold was measured by double ring electrodes in the proximal and distal urethra in 120 women. Univariate analysis using Kaplan-Meier models and multivariate analysis applying Cox regressions were performed to identify factors influencing urethral sensitivity in women. RESULTS: In univariate and multivariate analysis, women who had undergone radical pelvic surgery (radical cystectomy n = 12, radical rectal surgery n = 4) showed a significantly (log rank test P < 0.0001) increased proximal urethral sensory threshold compared to those without prior surgery (hazard ratio (HR) 4.17, 95% confidence interval (CI) 2.04-8.51), following vaginal hysterectomy (HR 4.95, 95% CI 2.07-11.85), abdominal hysterectomy (HR 5.96, 95% CI 2.68-13.23), or other non-pelvic surgery (HR 4.86, 95% CI 2.24-10.52). However, distal urethral sensitivity was unaffected by any form of prior surgery. Also other variables assessed, including age, concomitant diseases, urodynamic diagnoses, functional urethral length, and maximum urethral closure pressure at rest had no influence on urethral sensitivity in univariate as well as in multivariate analysis. CONCLUSIONS: Increased proximal but unaffected distal urethral sensory threshold after radical pelvic surgery in women suggests that the afferent nerve fibers from the proximal urethra mainly pass through the pelvic plexus which is prone to damage during radical pelvic surgery, whereas the afferent innervation of the distal urethra is provided by the pudendal nerve. Better understanding the innervation of the proximal and distal urethra may help to improve surgical procedures, especially nerve sparing techniques.     

Impotence following radical prostatectomy: Insight into etiology and prevention

This study was undertaken to identify the cause of impotence in men undergoing radical prostatectomy, with the hope that this information may provide insight into the possible prevention of this complication. The autonomic innervation of the corpora cavernosa in the male fetus and newborn was traced to determine the topographical relationship between the pelvic nerve plexus, and the prostate, urethra and urogenital diaphragm. We have demonstrated that the branches of the pelvic plexus that innervate the corpora cavernosa are situated between the rectum and urethra, and penetrate the urogenital diaphragm near or in the muscular wall of the urethra. Injuries to the pelvic plexus can occur in 2 ways: 1) during division of the lateral pedicle and 2) at the time of apical dissection with transection of the urethra. Thirty-one men who underwent radical retropubic prostatectomy were evaluated to determine risk factors that correlated with postoperative impotence: 5 (16 per cent) were fully potent, 7 (23 per cent) had partial erections that were inadequate for sexual intercourse and 19 (61 per cent) had total erectile impotence. The 2 factors that had a favorable influence on postoperative potency were age and pathologic stage of the lesion: 31 per cent of the patients less than 60 years old were potent versus only 6 per cent of the patients more than 60 years, while 33 per cent of the patients with tumor microscopically confined to the prostatic capsule were potent versus only 5 per cent of those with capsular penetration. When the factors of age and capsular penetration were combined 60 per cent of the men less than 60 years old who had an intact prostatic capsule were potent. Arterial insufficiency and psychogenic factors were excluded as major contributing factors by the finding of normal penile blood flow and absence of nocturnal penile tumescence in the impotent patients. We conclude that impotence after radical prostatectomy results from injury to the pelvic nerve plexus that provides autonomic innervation to the corpora cavernosa. Further studies will be necessary to determine whether refinements in surgical technique, especially during ligation of the lateral pedicle and apical dissection, can prevent this complication.     

Arterial vascularization of the lumbar vertebrae]

The authors have studied the vascularization in the lumbar verebrae. All arteries originate in the arteriae lumbales. They form an internal supply plexus and a peripheral periosteal plexus. The internal supply plexus is formed by radicular arteries divided into an anterior branch (the abdominal artery), with its corporeal branches, and a posterior branch (the dorsal artery) forming the arcus posterior. The periosteal plexus is formed by an anterior plexus for the corpus vertebrae and a posterior plexus for the arcus posterior. Intra-osseous vascularization at the level of the corpus vertebrae has been described; showing a difference between foetuses and adults. In the foetus, the posterior supply vessels predominate, whereas in the adult, the anterior periosteal vessels predominate. At the arcus posterior there is no difference between foetuses and adults.     

男性盆腔神经丛及神经血管束的应用解剖

目的认识盆丛、神经血管束（NVB）与周围组织器官的关系。方法对10例成人男性盆腔器官标本作盆丛、NVB大体解剖,1例43岁成人新鲜盆腔脏器作连续切片,观察盆丛、NVB与周围组织器官的关系。结果盆丛位于腹膜后、直肠的侧壁,呈网络状,精囊腺的后外侧,由盆丛发出的阴茎海绵体神经在前列腺后外侧走行,这些神经与前列腺被膜血管组成NVB。NVB的密度沿前列腺下行时逐渐变稀,在膜部尿道的外侧和后外侧分布于尿道旁的横纹肌中。结论明确盆丛、NVB位置以及与盆腔器官的毗邻关系,有助于术中有效鉴别和保护盆丛和NVB,达到保留性神经的盆腔、会阴部手术的目的。     

A spinal cord injured animal model of lower urinary tract function: observations using direct bladder and pelvic plexus stimulation with model microstimulators

BACKGROUND: Microstimulators are new devices that should be considered for management of lower urinary tract problems following spinal cord injury (SCI) such as urinary retention. These devices are small (less than 25 mm by 5 mm) with the electrodes located on the ends of the stimulator. However, it is not known whether the small electrodes on these devices would be effective in stimulating the plexus of nerves that innervate the bladder. The aim of the present study was to provide preliminary observations with model microstimulators (M-Micro) for inducing bladder contractions in an SCI animal model. Bladder wall and pelvic plexus stimulation sites were compared. Additional investigations evaluated parameters such as stimulation polarity, frequency, and period as well as bladder filling volume. METHODS: In an initial survival surgery, bilateral M-Micros were implanted on the bladder wall and the pelvic plexus along the urethra in 3 female cats. A second survival surgery was conducted 3 to 5 weeks later to produce a T1 0 SCI. Studies are reported following the second survival surgery. These studies included the effects of stimulation and bladder filling. RESULTS: The postmortem location of the implanted pelvic plexus M-Micro was previously described as near the bladder neck. Therefore, the pelvic plexus location is described in this report as "pelvic plexus (bladder neck)" stimulation. The observations showed effective stimulation with pelvic plexus (bladder neck) stimulation and voiding in some cases. Stimulation was limited by side effects of increased abdominal pressure and leg movement. Other factors also affected the response to stimulation, including the initial bladder volume and stimulating parameters. Fluoroscopy showed that when stimulation did not induce voiding the striated urethral sphincter was closed. CONCLUSIONS: This case series of 3 SCI animals showed that the small electrodes on the M-Micro could be used to stimulate the bladder with contractions and voiding in some cases. The pelvic plexus (bladder neck) location for the M-Micro may be a better location than higher on the bladder wall. Limiting side effects of stimulation included leg movement and increased abdominal pressure. Additional important factors included the stimulation parameters, initial bladder volume, and the function of the skeletal urethral sphincter.     

组织工程组织血管化研究新进展

组织工程的血管化问题是制约组织工程产品的关键问题之一。根据血管发生中内皮细胞的来源不同，将血管发生分血管生成和血管再生两种形式，两种血管形成的方式都是一个动态、复杂的生理过程，通过生长因子和粘附物质来调节。对组织工程组织的血管化研究模型有体外和体内两种。体外实验可以检测支架与内皮细胞的粘附、增殖及迁移、材料的细胞毒、血管化效应和各种生长因子的调节作用，体内最简单实用的模型是用鸡胚茸毛尿囊膜模型，更高等的实验模型是在完整的动物体。组织工程组织血管化的策略有对支架材料的表面结构进行修饰、在材料内复合缓释的生长因子、内皮细胞与其它种子细胞联合培养、体内血管网包裹、血管束植入、血管模板以及体外在人造组织内构造微血管等，但目前的方法或多或少地存在一些问题，相信随着对血管化的机制和分子基础的了解的不断深入，以及各种技术手段的不断发展、完善，最终会找到比较理想的血管化方法。     

腹膜外腹腔镜下根治性前列腺切除术的临床解剖学研究

目的结合腹腔镜下根治性前列腺切除术术式特点,寻找盆腔定位标志,以提供理论知识和减少术后并发症。 方法解剖7例成年男性盆腔标本,观察膀胱颈、前列腺侧方及尖部周围组织,并测量定位。 结果膀胱颈与前列腺底交界处有两条肌性纵行纤维束,横径为（4.42±1.38）mm,距离膀胱正中线（1.78±0.32）mm。膀胱前列腺间沟后外侧有一较恒定的前列腺动脉干,距沟（16.34±5.76）mm处呈"爪"形分支。盆丛位于直肠两侧,其上部内侧发出直肠丛。下部纤维在前列腺后外侧构成宽约5.40 mm的神经血管束（NVB）。NVB内含海绵体神经,于前列腺尖部5点、7点外（2.84±0.56）mm处进入。阴茎背神经在距前列腺尖部（2.78±1.04）mm处发出细小分支,进入尿道外括约肌的5点、7点。括约肌亦受NVB发出的细小纤维支配,分布于3～5点、7～9点位。 结论术中离断膀胱颈部时,可根据膀胱颈部肌性纵行纤维束位置切开。以膀胱前列腺间沟为标志,距离其25 mm以上结扎动脉。通过辨认NVB中的小血管避免损伤海绵体神经。分离前列腺尖部、离断尿道、吻合膀胱颈尿道时,勿损伤其5、7点位的神经。术中寻找上述标志,最大程度保留组织,为减少术后并发症提供了参考。     

Anatomic study of arterial and venous cavernospongious shunt in the human penis: surgical findings

The vascularization of the penis corpora cavernosa and the corpus spongiosum of foetus, children and adults was studied via intra-vascular injection with gelatenous india ink. The microscopic vision of sagittal and transvers sections of the penis showed perforate deep arterial system of the cavernosa directly anastomosed the urethral submucosal arteries in order to establish the shunt between the corpora cavernous arteries and spongious arterial network. Those vascular connection systems of the penis provided well diffusion of the drugs.     

Anatomic and functional studies of the male and female urethral sphincter

A total of 28 human specimens (14 male, 14 female) was used to perform macro- and microscopic studies on the morphologic basis of the urethral continence mechanism. Furthermore, functional studies were performed in six sheep, with the aim of looking at the pudendal and autonomic innervation of the urethra and the rhabdosphincter, as well as the changes of autonomic innervation after selective denervation. Transurethral ultrasound was performed in 34 continent patients, in order to visualize the contractions of the rhabdosphincter. The membranous urethra is innervated by branches of the autonomic pelvic plexus. The rhabdosphincter is an omega-shaped loop of striated muscle fibers that is innervated by the pudendal nerves. These results are supported by the results of animal experiments that show that the autonomic nerves predominantly innervate and regulate the upper part of the urethra, whereas stimulation of the pudendal nerves leads to a contraction of the lower part of the sheep urethra. In electron-microscopy, marked degeneration of the smooth muscle cells could be seen in the sheep with bilateral denervation.     

Application of ultrasound contrast agents for the characterization of female urethral vascularization in healthy pre- and postmenopausal volunteers: preliminary report

OBJECTIVES: Vascularization of the female urethra is an important factor contributing to the sealing effect responsible for the normal urethral closing system. The aim of this study was to assess whether contrast enhanced ultrasonography can be used to evaluate changes in urethral vascularization between pre- and postmenopausal women. METHODS: We studied the vascularization of female urethra in 11 healthy premenopausal females during the midfollicular phase of the menstrual cycle and 10 healthy postmenopausal volunteers using ultrasound contrast agents with a 2-5 MHz curved-array transducer by a translabial approach. Reperfusion curves were analyzed by a blinded investigator. Ultrasound contrast agents were measured with specifically designed software, and results were evaluated using the Mann-Whitney U-test. RESULTS: The data suggest that the enhancement characteristics of the urethra were different in pre- and postmenopausal women and that the percent of blood volume and blood flow decreased with age. No changes were observed between pre- and postmenopausal women regarding the velocity of blood flow. CONCLUSIONS: The study of female urethra vascularization by ultrasound contrast agents is safe, feasible, and noninvasive.     

Morphology of peripheral nerves, their sheaths, and their vascularization

This review aims to update our understanding of peripheral nerves, including the nature and function of their sheaths and, finally, their vascularization. The peripheral nervous system is made up of nerves whose function is to gather stimuli from the periphery as well as to transport the motor, secretory or vegetative responses that are triggered to the periphery. The connective tissue surrounding peripheral nerves all along their extension is made up of endoneurial, perineurial and epineurial. The endoneurium surrounds individual axons, which are grouped in fasciculi, each of which is surrounded by the perineurium and finally, the group of fasciculi that comprise all the axons present in this nerve are surrounded by the epineurium. Axons form an intraneural plexus such that they occupy positions in the various fasciculi along the trajectory of the plexus. The number and size of fasciculi vary along the trajectory of a nerve as a result of the plexus positioning of the axons. Peripheral nerves are richly vascularized throughout their length, with multiple anastomoses forming the intraneural vascular network, which is made up mainly of arterioles, capillaries, postcapillary venules and venules. Regarding the blood-nerve barrier and the existence of capillary permeability: endoneural capillaries have junctions that are stronger than those of the endothelial cells of vessels in the epineurium and perineurium. Two distinct lymph channels networks are present in the peripheral nerve stems and are separated by the perineural barrier. The nervi-nervorum are special nerves of a sympathetic and sensory nature that arise from the nerve itself and the perivascular plexuses.     

A study of the myelinated fibres in the branches of the pelvic plexus

In a 20-year-old human female specimen the nerves to the pelvic organs were dissected and analysed. The gross anatomy of the branches of the pelvic plexus was described. The composition of these nerves was studied and the sizes and distribution of the diameter of a great part of the myelinated nerve fibres were measured and analysed. It was confirmed that the ventral roots S2 and S3 contain many nonmyelinated nerve fibres. There are direct connections between the sacral sympathetic chain and the pelvic plexus. They contain myelinated fibres with sizes as large as 11 μm. There are two different groups of fibres which supply the bladder, one on the dorsal side, mainly nonmyelinated (postganglic sympathetic?), and another group to the lateral side which contains many thin myelinated fibres (parasympathetic preganglionic?). The pelvic plexus and its branches are fixed to the vagina and the rectum. Surgical interventions in this area and perhaps also childbirth can damage the nerve supply to the bladder and the urethra. The functional disturbances of the bladder after such interventions can depend on what group of nerve fibres is most seriously damaged. The large number of thick myelinated fibres which reach the ventro lateral side of the urethra makes it highly probable that these fibres innervate the intrinsic striated urethral musculature. The large number of nonmyelinated nerve fibres in the nerves to the m. levator ani probably innervate smooth muscle tissue which is found in the fasciae of the pelvic floor.     

A Spinal Cord Injured Animal Model of Lower Urinary Tract Function: Observations Using Direct Bladder and Pelvic Plexus Stimulation With Model Microstimulators

Abstract

Background: Microstimulators are new devices that should be considered for managementof lower urinary tract problems following spinal cord injury (SCI) such as urinary retention. These devices are small(less than 25 mm by 5 mm) with the electrodes located on the ends of the stimulator. However, it is notknown whether the small electrodeson these devices would be effective in stimulating the plexus of nervesthat innervate thebladder. The aim of the present study was to provide preliminary observations with modelmicrostimulators (M-Micro) for inducing bladder contractions in an SCI animal model. Bladder wall andpelvic plexus stimulation sites were compared. Additional investigations evaluated parameters such asstimulation polarity, frequency, and period as well as bladder filling volume.

Methods: In an initial survival surgery, bilateral M-Micros were implanted on the bladderwall and the pelvic plexus along the urethra in 3 female cats. A second survival surgerywas conducted 3 to 5 weeks laterto produce a Tl 0 SCI. Studies are reportedfollowing the second survival surgery. These studies included the effects of stimulation and bladder filling.

Results: The postmortem location of the implanted pelvic plexus M-Micro was previouslydescribed asnear the bladder neck. Therefore, the pelvic plexus location is described in this reportas “pelvic plexus(bladder neck)”stimulation. The observations showed effective stimulation with pelvic plexus (bladder neck)stimulation andvoiding in some cases. Stimulation was limited byside effects of increased abdominalpressure and leg movement. Other factors also affected the response to stimulation, includingthe initial bladder volume and stimulating parameters. Fluoroscopy showed that when stimulation did not inducevoiding the striated urethral sphincter was closed.

Conclusions: This case series of 3 SCI animals showed that the small electrodes on the M-Micro could beused to stimulate the bladder with contractions and voidingin some cases. The pelvic plexus (bladder neck)location for the M-Micro may be a better location than higher on the bladder wall. Limiting side effects ofstimulation included legmovement and increased abdominal pressure. Additional important factors included the stimulation parameters, initial bladder volume, and the function of the skeletal urethral sphincter.     

Mechanical irritation induces neurogenic inflammation in the rat urethra.

A catheter was inserted into the urethral meatus of urethane-anaesthetized rats and rotated (30 rotations/minute) during a three minute period. One hour later, microvascular permeability in the distal urethra was evaluated by means of the Evans Blue leakage technique. Dye extravasation increased significantly (74 +/- 12 ng./mg. of wet tissue weight, p less than 0.05), as compared to control values (18 +/- 2 ng./mg.). The effect of catheterism was prevented by about 50% by systemic pretreatment with capsaicin performed in either adult or newborn rats, as well as by bilateral removal of pelvic ganglia. Furthermore, pretreatment with capsaicin of adult rats, combined to pelvic ganglionectomy, virtually abolished the inflammatory response produced by mechanical irritation of the urethra. These results indicate that: 1) the increase of vascular permeability produced by mechanical irritation is nerve-mediated, 2) capsaicin-sensitive afferents participate in the inflammatory process and 3) capsaicin-insensitive nerves, which pass through the pelvic ganglia, contribute to the overall response.     

Neurocutaneous island flaps in the hand: anatomical basis and preliminary results.

The neurocutaneous flap is an axial flap composed of one vein and one nerve, the arterial vascularisation of which is provided by the vascular plexus around and inside the nerve. The vascularisation of the radial and ulnar nerves on the dorsal aspect of the hand were studied in 20 fresh upper limbs. There is always a consistent arterial longitudinal plexus alongside the nerves, which links the cutaneous perforating arteries. On the basis of our anatomical findings, neurocutaneous island flaps with retrograde flow were raised on the hands of five patients and are reported on.