The anatomy of midurethral slings and dynamics of neurovascular injury

The aim of this study was to investigate the course of midurethral slings using tension-free vaginal tape. The TVT procedure was performed on six fresh pelves, measurements were obtained, and the structures were cross-referenced in 16 embalmed pelves. The midurethral sling enters the suburethral tissue 2.2–3 cm caudad to the internal urethral meatus, pierces the paraurethral musculature and vascular plexus, and exits 2±0.5 cm from the midline lateral to the point of insertion of the arcus tendineus fasciae pelvis. On the pubic tubercle the sling is 4±0.5 cm, 4±1 cm and 6±1 cm from the accessory obturator, the inferior epigastric and the external iliac vessels, respectively. The critical angle of error resulting in the external iliac vessel injury is 7–15°. A current knowledge of pelvic anatomy may help the surgeon avoid the neural and vascular structures that are in the path of the sling.Editorial Comment: The authors are to be commended for the completion of a detailed observational study further investigating the course of the TVT tunneler during placement of the sling material. An unpublished study reported by Walters et al. found similar relationships between the TVT tunneler and the surrounding pelvic vasculature. Both of these studies highlight the importance of avoiding excessive lateral deviation or rotation of the TVT tunneler during placement.The conceptualization of a dynamic pelvic anatomy in relation to the advancing tip of a midurethral sling trocar is advocated to lessen intraoperative complications.S. Abbas Shobeiri can also be reached at     

Transobturator surgery for female stress incontinence: a comparative anatomical study of outside-in vs inside-out techniques

OBJECTIVE To assess the specific risks of injury to neural and vascular structures inherent in two approaches to transobturator surgery for inserting a suburethral sling, i.e. the outside-in (standard technique) and inside-out approaches. MATERIALS AND METHODS The study comprised seven cadavers, providing 14 obturator regions. Five specimens had a tape inserted outside-in on one side, and inside-out on the other; of the remaining two cadavers, one had an inside-out tape and one an outside-in tape, bilaterally. After tape insertion, the cadavers were dissected. Particular attention was paid to the distances between the tape and the deep external pudendal vessels, and between the tape and the posterior branch of the obturator nerve. RESULTS With the inside-out technique, the safety margins were reduced, and the external pudendal vessels and the posterior branch of the obturator nerve were at greater risk of injury. CONCLUSION The two techniques are not equivalent, with a lower risk of injury to vascular and nerve structures with the outside-in technique.     

Transoral Surgery: An Anatomic Study

The transoral approaches have become commonplace in modern neurosurgical practice for treatment of ventral midline lesions of the clivus and upper cervical spine. Although the standard technique of transoral surgery is conceptually simple, anatomic relationships are not so readily appreciated. The present study was undertaken in an effort to define more clearly the midline anatomic relationships as they pertain to the standard transoral and transpalatine operations. The anatomic relationships involved in planning microsurgical transoral approaches were examined in 15 human cadavers. Landmarks approximating the midline of the skull base and the upper cervical spinal canal were defined to assist the surgeon's orientation. Measurements were made in axial, sagital, and parasagittal planes to various neurovascular structures in the posterior cranial fossa and upper cervical spinal canal. The study revealed that, for the standard transoral and transoral-transpalatine dissections, the carotid arteries, abducens nerves, interior petrosal sinuses, hypoglossal nerves, and vertebral arteries would be a greatest risk being 0.76, 1.06, 1.51, 1.34, and 1.52 cm from the midline at specified locations. The measurements and the computed tomography images provide a useful reference for the surgeon.     

Transoral surgery: an anatomic study

The transoral approaches have become commonplace in modern neurosurgical practice for treatment of ventral midline lesions of the clivus and upper cervical spine. Although the standard technique of transoral surgery is conceptually simple, anatomic relationships are not so readily appreciated. The present study was undertaken in an effort to define more clearly the midline anatomic relationships as they pertain to the standard transoral and transpalatine operations. The anatomic relationships involved in planning microsurgical transoral approaches were examined in 15 human cadavers. Landmarks approximating the midline of the skull base and the upper cervical spinal canal were defined to assist the surgeon's orientation. Measurements were made in axial, sagital, and parasagittal planes to various neurovascular structures in the posterior cranial fossa and upper cervical spinal canal. The study revealed that, for the standard transoral and transoral-transpalatine dissections, the carotid arteries, abducens nerves, interior petrosal sinuses, hypoglossal nerves, and vertebral arteries would be a greatest risk being 0.76, 1.06, 1.51, 1.34, and 1.52 cm from the midline at specified locations. The measurements and the computed tomography images provide a useful reference for the surgeon.     

Anatomy of the posterior iliac crest as a reference to sacral bar insertion

There are no detailed anatomic studies focusing on the posterior iliac crest although it frequently is used for posterior stabilization of unstable pelvic fractures. Anatomic dissections were done to evaluate the size of the extraarticular region of the posterior iliac crest and its relationship to the lumbosacral lamina and to show on cadavers the level of sacral bar placement that offers safe and solid fixation. Sixty cadavers were dissected bilaterally. Fifty-one were male and nine were female. The distance between the posterior wall of the sacral canal and the tip of the iliac crest was measured at various levels between the level of the upper border of L5 lamina to the level of the posterosuperior iliac spine. In all the dissections the greatest distances were at the level of the L5-S1 junction, which consequently is the safest level for good bony purchase. The entire length of the posterior iliac crest from the level of the upper border of L5 lamina to the posterosuperior iliac spine was shown to be appropriate for safe and solid bar fixation because all of the distance measurements were greater than 13 mm, which is the smallest safe distance. Below the posterosuperior iliac spine level, insertion of the sacral bars was dangerous because the average measured distance was only 10.38 mm.     

Pelvic floor anatomy in classic bladder exstrophy using 3-dimensional computerized tomography: initial insights

PURPOSE: We present the pelvic floor anatomy of the major pelvic floor musculature in classic bladder exstrophy, including the levator ani, obturator internus and obturator externus. By improving our knowledge of pelvic floor anatomy we hope to understand better the relationship of the pelvic floor to the bony anatomy as well as the role of osteotomy in changing pelvic floor anatomy to enhance urinary control after surgery. MATERIALS AND METHODS: 3-Dimensional computerized tomography was done in 6 boys and 1 girl, including 5 patients 2 days to 5 months old (mean age 7 months) undergoing primary closure and 2 who were 4 and 8 years old undergoing repeat closure. The pelvic floor musculature, including the levator ani, obturator internus and obturator externus, in these cases was compared to that in 26 age and sex matched controls. RESULTS: The levator ani musculature encompasses a significantly wider area of 9.5 cm.2 in patients with classic bladder exstrophy than in controls. The anterior segment of the levator ani was shorter (1.2 cm.) and the posterior segment of the levator ani was longer (2.5 cm.) than in controls. The degree of divergence of the levator ani in classic exstrophy was significantly more outwardly rotated (38.8 degrees) than controls. In addition, the transverse diameter of the levator hiatus was 2-fold that in our control group and in that of published controls, while the length of the hiatus was 1.3-fold that in normal controls. There was also significant flattening, involving a 31.7 degree decrease in steepness between the right and left halves of the levator ani, of the puborectal sling in classic bladder exstrophy versus controls. Because of these findings, there is more anterior superior rotation in the pelvic floor in exstrophy cases. The obturator internus was more outwardly rotated (15.1 degrees) in exstrophy and the obturator externus also showed more outward rotation (16.9 degrees) than in controls. CONCLUSIONS: This study provides better understanding of the pelvic floor anatomy in classic bladder exstrophy. Significant differences have been documented in the pelvic floor in classic bladder exstrophy cases and controls. Hopefully these differences may have a pivotal role in providing new insight into long-term issues, such as urinary and fecal incontinence, and pelvic organ prolapse, in classic bladder exstrophy.     

Redefining the "Arcade of Struthers"

PURPOSE: To define the anatomy and presence of the arcade of Struthers, its anatomic variations, and potential sites of compression of the ulnar nerve. METHODS: In 11 fresh specimen dissections, the ulnar nerve was followed from the brachial plexus through the anterior compartment into the posterior compartment through the intermuscular septum and the arcade of Struthers on to the cubital tunnel. The arcade was identified, dissected, measured, and photographed. All anatomic variations were documented. RESULTS: The arcade of Struthers and intermuscular septum were present in all 11 specimens. The arcade was not merely an opening in the septum nor was it a short band as typically described: the arcade was better described as a fibrous canal with an average length of 5.7 cm. Its openings at either end were 3.9 and 9.6 cm proximal to the medial epicondyle. The structural components of the canal consisted of the fibrous tissue of the intermuscular septum, the internal brachial ligament, the deep fascia of the triceps, and the epimysium of the triceps muscle itself. The ulnar nerve was bound tightly within the entire canal in one case. In all specimens the nerve had an hourglass indentation at the proximal opening of the canal between the intermuscular septum and the internal brachial ligament. CONCLUSIONS: The arcade of Struthers consists of a fibrous canal. The tightest point is the proximal end of the canal at the intermuscular septum that represents the clinically relevant site of entrapment or compression of the ulnar nerve.     

Corona Mortis血管解剖学研究及其临床意义

目的:探讨闭孔血管和髂外血管在腹股沟区的分支,为减少髂腹股沟入路术中出血提供解剖学基础。方法:对25具新鲜中国成人尸体标本共50侧半骨盆进行解剖学研究,观测闭孔血管和髂外血管在腹股沟区的分支及其吻合支(CoronaMortis血管)的大小、出现率、吻合血管行径和吻合血管至耻骨联合的距离。结果:72%(36侧)耻骨上支表面至少存在1条血管吻合支,其中28%(14侧)存在2条或3条血管吻合支,24%(12侧)同时存在动脉吻合支和静脉吻合支。耻骨上支表面的血管吻合支平均直径2.6mm(2.0～4.2mm)。血管吻合支紧贴耻骨上支或髂耻隆起,几乎垂直地下行于髋臼窝壁或耻骨支后方,经闭膜管出盆腔,血管吻合支与耻骨联合的平均距离52mm(38～68mm)。在此区域手术以及髋臼或骨盆前环骨折极易损伤CoronaMortis血管。结论:闭孔血管和髂外血管的吻合支较粗,出现率高,位于耻骨上支表面。髂腹股沟手术入路应特别注意CoronaMortis血管的存在。     

Anatomical study of the obturator foramen and dorsal nerve of the clitoris and their relationship to minimally invasive slings

Objectives The objective of the study is to clarify potential risks to the dorsal nerve of the clitoris (DNC) and obturator canal using different minimally invasive slings.Study design Ten embalmed hemipelves were dissected to demonstrate the course of the DNC and the obturator canal. On each cadaver, tension-free vaginal tape (TVT), transobturator in–out (TVT-O) and transobturator out–in (Monarc) procedures were performed. Distances between the DNC and the obturator canal to the different devices were measured.Results The DNC passes beneath the pubic bone at a distance of 14.3±4.7 mm of the midline. The distances of the different devices to the DNC were similar. The distance to the obturator canal was significantly different, with TVT being the furthest (40.1±3.7 mm) and TVT-O the closest (19.3±3.1 mm; p<0.0001).Conclusion Given the course of the DNC along the medial aspect of the ischiopubic ramus, the out–in technique may be safer. The in–out technique is the closest to the obturator canal.     

Complications associated with transobturator sling procedures

This study aims to determine the complications associated with trans-obturator slings as reported to a national database. We required “MAUDE”, a database that collects reports of complications associated with medical devices and which is maintained by the Food and Drug Administration. We searched for complications associated with three different, commercially available trans-obturator slings. We then tabulated the results by type of complication, by date of occurrence, and by type of sling. Between January 2004 and July 2005, 140 reports of 173 complications associated with trans-obturator tapes were reported to the MAUDE database. Previously unreported injuries, such as obturator nerve injuries, large blood losses (≥600cc), and ischiorectal fossa abscesses, were documented. Serious complications occur with the trans-obturator tape systems, but the rates are unknown due to database limitations. The type of complication appears to differ between devices and this may reflect different implantation systems and different polypropylene mesh formulations. Improved tracking of device complications is necessary to maximize patient safety.     

Transobturator vaginal tape inside out for the surgical treatment of female stress urinary incontinence: anatomical considerations

PURPOSE: We have recently described a novel surgical technique for female stress urinary incontinence, that is the transobturator vaginal tape inside out, which uses specific instruments for the passage of a synthetic tape from beneath the urethra toward the thigh folds. Herein we report the results of cadaver dissection performed to determine the anatomical trajectory of the tape and its relationships with neighboring neurovascular structures and organs. MATERIALS AND METHODS: Insertion of the transobturator vaginal tape inside out tape was performed by different surgeons in 12 freshly frozen female cadavers according to the standard procedure. The thigh, obturator, perineal and pelvic regions were dissected and tape trajectory was recorded. An additional cadaver was dissected without prior tape placement. RESULTS: The tape was inserted according to a certain consistent path, that is penetration from the suburethral space into a strictly perineal region limited medial and cranial by the levator ani muscle, caudal by the perineal membrane and lateral by the obturator internus muscle. This region corresponded to the most anterior recess of the ischiorectal fossa. The tape then perforated the obturator membrane and muscles, and exited through the skin after traversing adductor muscles and subcutaneous tissue. The tape was coursed away from 1) the dorsal nerve to the clitoris located more superficially below the perineal membrane, 2) the obturator nerve and vessels, and 3) the saphenous and femoral vessels. CONCLUSIONS: These findings strongly suggest that our transobturator technique is highly accurate, reproducible and safe, and it does not require perioperative cystoscopy.     

An anatomic comparison of the original versus a modified inside-out transobturator procedure

Introduction and hypothesis

The objective of this study was to evaluate the modification of a shortened tape and reduced dissection of the inside-out transobturator procedure on the tape??s relationship to the relevant anatomical structures.

Methods

In ten fresh frozen cadavers, relevant distances between the two different tapes and anatomical structures were recorded.

Results

The shorter tape traversed less muscular structures, but consistently traversed the obturator membrane. The median distance from the tape to the obturator canal measured 2.0 versus 1.9?cm, to the anterior obturator nerve 3.0 versus 2.7?cm, and to the posterior obturator nerve 2.2 versus 2.0?cm [modified versus original procedure, respectively (p?>?0.05)]. Significantly, less mesh was inserted in the modified procedure on each side of the body (6.1 versus 9.9?cm, p?Conclusions The shorter, inside-out transobturator tape traverses less muscular structures than its original counterpart, while still consistently anchoring in the obturator membrane at a similarly safe distance from the obturator canal.     

改良Stoppa入路死亡冠血管的解剖学研究

目的研究改良Stoppa入路髂外和腹壁下血管与闭孔血管在耻骨上支区的吻合支（死亡冠）解剖学特点,为提高骨盆髋臼前路手术操作安全性提供解剖学基础。方法模拟改良Stoppa入路对12具国人成人尸体标本共24侧半骨盆进行解剖学研究。观测死亡冠血管的出现率、直径大小、长度及其至耻骨联合和髂耻隆起的距离。结果87．5％（21侧）耻骨上支表面存在死亡冠血管,其中62．5％（15侧）为静脉型,8．3％（2侧）为动脉型,16．7％（4侧）为混合动静脉型。死亡冠血管的长度平均32．1（24．1～40．6）mm,直径平均2．5（2．0～3．7）mm。死亡冠血管至耻骨联合距离平均54．9（47．8～63．8）mm,至髂耻隆起距离平均20.3（6．2～35．0）mm。死亡冠血管紧贴耻骨上支,移动度小。结论死亡冠血管出现率高,变异度大,以静脉型为主。移位骨盆前环髋臼骨折及前入路手术时易损伤死亡冠血管,应注意其存在并妥善处理,推荐骨膜下剥离。     

Neuro-anatomy of the posterior parametrium and surgical considerations for a nerve-sparing approach in radical pelvic surgery

Background

Efforts to improve approaches to the so called “parametrium” with minimally invasive and less dangerous techniques have led to a better study of the anatomic location and composition of that region. Nevertheless, many misconceptions and confusions about the anatomy of the posterior parametrium and its structures still remain. This study aimed to review anatomic and surgical data and to identify several clear landmarks and surgical steps for a nerve-sparing approach to posterior parametrectomy in the course of radical pelvic surgery with or without rectal resection.

Methods

The literature and anatomic dissections of fresh, embalmed, and formalin-fixed female pelvis cadavers were reviewed. The authors’ laparotomic and laparoscopic case series also was reviewed for deep-infiltrating endometriosis as well as uterine, ovarian, and rectal cancer.

Results

The anatomic entity commonly termed the “posterior parametrium” can be identified as the conjunction of three important anatomic structures (ligaments): the cranial structure (uterosacral ligaments), the caudad structure (rectovaginal ligaments), and the laterocaudad structure (lateral rectal ligaments). Identification of these structures (containing autonomic innervations for pelvic viscera) may allow an accurate nerve-sparing surgical approach in many radical pelvic operations.

Conclusions

The incidences of urinary, rectal, and sexual morbidity after radical pelvic surgical procedures for oncologic diseases (rectal/ovarian cancer, advanced endometrial/cervical cancer, posterior pelvic recurrences) and deep severe endometriosis can be reduced by better knowing and dissecting the right embryo-anatomic planes of the so-called “posterior parametrium.”     

经会阴修复重建男性尿道的应用解剖

目的探讨经会阴修复重建男性尿道的解剖学基础,寻求减少损伤的方法. 方法防腐成年男尸12具,经会阴逐层解剖至尿道前列腺尖部,观察层间结构和联系、尿道前列腺尖部和膜部周围结构,测量有关数据;另用新鲜男尸3具,模拟经会阴修复重建男性尿道手术操作. 结果支配阴囊、会阴及尿道球部的动、静脉及神经均是从两外侧走向中线;前尿道海绵体的腹、背侧与相邻组织间有致密纤维组织相连接.阴茎海绵体神经呈网状紧贴前列腺表面从底部走向尖部,穿过尿生殖膈,呈网格状展开,神经束网宽为(12.11±2.32) mm. 结论会阴结构复杂,手术时靠中线操作可减少损伤;在膜部尿道外侧5 mm的范围内操作,从前外侧紧贴前列腺表面分离前列腺尖部组织,可避免损伤神经束.     

The anatomic basis of the gracilis perforator flap.

Another perforator flap, the gracilis perforator flap, has recently been added to the armamentarium of reconstructive surgeons. A detailed study of the anatomy of this flap was undertaken in this study. Forty-seven dissections were performed in cadavers and clinical cases of gracilis muscle harvesting for various reconstructive reasons. According to our findings, at least one musculocutaneous perforator of large calibre was found in the majority of the dissections performed (87%), emanating from the proximal third of gracilis. All the perforators were located within a radius of 7 cm from the point of entrance of the gracilis main vascular pedicle. In their majority, they emanated proximal to that point (83%) from the middle part (anteroposterior axis) of the muscle (62%). The intramuscular course of the perforators was easily followed and few muscular branches were encountered, before they joined the main vascular pedicle. A sensory branch of the anterior obturator nerve, accompanying the perforators, was occasionally found (29%). Finally, a superficial vein, branch of the greater saphenous, was always found within the skin territory of the flap in all dissections performed in cadavers.     

The vascular anatomy anterior to the L5-S1 disk space

STUDY DESIGN: Dissection of 37 human cadavers was performed to assess the variability in the vascular anatomy anterior to the L5-S1 disc space. OBJECTIVES: To determine the variability of the anterior vascular anatomy at the L5-S1 disc space, and to assess its reliability as an anatomic landmark for the placement of anterior interbody fusion devices. SUMMARY OF BACKGROUND DATA: Although multiple studies have defined both the lumbar spinal anatomy and the anatomy of the great vessels, the relation of the great vessels to the anterior L5-S1 disc space has not been quantified directly. METHODS: This study investigated 35 human cadavers (17 males and 18 females). The anterior L5-S1 disc space and great vessel bifurcation were exposed through a transabdominal approach. Two independent observers each obtained 10 measurements in each specimen. RESULTS: The middle sacral artery was present in 100% of the specimens, averaging 2.5 mm in width. Its location in relation to the midline was quite variable, with a range greater than 2 cm in both the top and bottom of the disc. The distance from the bifurcation to the top of the L5-S1 disc averaged 18 mm (range, 7-36 mm). The total width between the left common iliac vein and the right common iliac artery averaged 33.5 mm (range, 12-50 mm). CONCLUSIONS: The middle sacral artery, present in 100% of the specimens, is a poor anatomic landmark for locating the midline at L5-S1. Because the average space available between the left common iliac vein and the right common iliac artery is 33.5 mm, and because the left common iliac vein averages only 12 mm from midline, the surgeon must be prepared to mobilize the local vasculature in most cases to expose the L5-S1 disc space adequately.