The surgical anatomy of needle bladder neck suspension

The surgical anatomy of needle bladder neck suspension

The Surgical Anatomy Suspension CHRlSTOPHER C. FITZPATRICK, JOHN 0. L. DeLANCEY, MD of Needle Bladder Neck MB, MRCOG, Objective: To define the surg...

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The Surgical Anatomy Suspension CHRlSTOPHER C. FITZPATRICK, JOHN 0. L. DeLANCEY, MD

of Needle Bladder Neck

MB, MRCOG,

Objective: To define the surgical anatomy of needle bladder neck suspension in order to explain this operation’s effect on urethral support and gain information useful in minimizing intraoperative complications. Methods: Needle bladder neck suspension was carried out on two unembalmed, multiparous cadavers. After fixing the suspensory sutures in place, the pelvis of one cadaver was completely dissected. The second cadaver was serially sectioned at l-cm intervals, and the sections were subjected to both anatomic and histologic examination. These findings were correlated with the findings noted during an autopsy dissection of a woman who previously had undergone needle bladder neck suspension at our institution and with our surgical experience with this operation. Results: The plane of dissection used to enter the space of Retzius lay between the vaginal mucous membrane and the visceral endopelvic fascia. The point of entry into the retropubic space lay between the levator ani muscles and its superior fascia, lateral to the arcus tendineus fasciae pelvis, the paraurethral vascular plexus, and bladder neck. It was cephalad to the perineal membrane (urogenital diaphragm). The paraurethral supporting tissues incorporated in the suspensory suture included the portion of the endopelvic fascia that lies between the vagina and urethra and, usually, the arcus tendineus fasciae pelvis. Attaching the suspensory sutures in needle bladder neck suspension seems to stabilize the bladder neck by providing a new point of lateral fixation for its supporting endopelvic fascia. Conclusion: Needle bladder neck suspension stabilized the supportive fascia of the urethra, and vascular injury may be minimized by detailed knowledge of paraurethral anatomy. (Obstet G!ynecol 7996;87:41-9)

Needle bladder-neck suspension operations are established techniques for treating stress urinary incontinence due to poor urethral support. Several modifications in technique have been made since it was

THOMAS

described by Pereyra in 1959.’ Recently, these were summarized by Karram and Bhatia.2 Transvaginal entry into the space of Retzius lateral to the bladder neck and incorporation of supportive tissue into suspensory sutures are key points in these operations. Despite the apparent similarity in dissection used by various surgeons using this technique, the anatomic terms used to describe the plane of dissection and supportive tissues vary considerably from one report to another, making it difficult for those who previously have not performed this operation to understand what the authors have done. Furthermore, the effect of this operation on the supportive structures of the urethra remains incompletely defined. The purpose of this study was to define the surgical anatomy of needle bladder neck suspension operations that require entry into the space of Retzius. Our findings should prove helpful both in providing a clear idea of the influence of this type of operation on the mechanism of urethral support and also help minimize vascular and bladder trauma. In choosing anatomic terms, we adhered to the Nomina Anatomica,” using corresponding English-language clinical terms when appropriate.

Materials and Methods Two unembalmed premenopausal multiparous cadavers were used in the first part of this study. Each cadaver was placed in the lithotomy position, and the vagina was exposed with a posterior speculum. A size 16-Fr Foley catheter was inserted into the bladder. The catheter balloon was inflated with 10 mL of water and used to identify the bladder neck. One cadaver had a needle bladder neck suspension performed through a midline vaginal wall incision; in the other cadaver, it was performed through a paraurethral incision. Using

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E. ELKINS, MD, AND

sharp

dissection,

and mobilized

the

vaginal

bilaterally

mucosa

was

un-

so that the under-

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Figure 1. Cadaver dissection showing plane of entry into retropubic space. A portion of the perineal membrane (urogenital diaphragm) has been excised to reveal the position of the levator ani muscles. Note that the perineal membrane, containing the clitoral vessels, and levator ani muscles are caudal to the plane of dissection.

Levator ani muscle lschio cavernosus muscle Dorsal artery of the clitoris Perineal

membrane

-

Bulbo cavernosus muscle

lying endopelvic fascia was exposed. The space of Retzius was then entered on the right side by sharply perforating the endopelvic fascia lateral to the bladder neck. Entry was gained by advancing Metzenbaum scissors, held approximately 30” from the horizontal plane, along the inner aspect of the ischiopubic ramus. When the space of Retzius was entered, the opening was enlarged to accommodate the distal phalanx of the surgeon’s index finger. The tissue adjacent to the bladder neck, into which the suspensory suture was to be placed, was then identified. A helical suture was inserted into the tissue adjacent to the vesical neck and further secured by incorporating the full thickness of the vaginal wall, excluding the vaginal mucosa. The suture was then transferred superiorly using the Stamey needle and secured to the sheath of the rectus abdominis muscle. The contralateral side of the cadaver in each instance was left undissected to provide a view of the undisturbed tissues for reference. With a finger in the operative field, the abdominal incision and dissection were both extended. The space of Retzius was entered transabdominally, and the site of transvaginal perforation and suture placement was located. The structures of the pelvic sidewall were widely exposed and identified on that side. In one of the cadavers, a complete dissection of the pelvis was carried out to identify the levator ani, perineal membrane (urogenital diaphragm), endopelvic fascia, pelvic nerves, and blood vessels. Documentary photographs were taken and illustrations were drawn from these.

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The other cadaver was prepared for serial section. A plastic tube replaced the surgeon’s finger to keep open the communication into the space of Retzius. The pelvis was fixed by immersion in buffered 10% formalin solution for a period of 2 months. After fixation, the cadaver was cooled gradually, first to OC, then to -2OC, and finally to -7OC, to prevent the formation of ice crystals in the specimen. When frozen, the specimen was trimmed, then serially sectioned at l-cm intervals along a plane that allowed the entire length of the communication between the vaginal and retropubic space to be visualized in a single section. The sections were labeled, photographed, and studied in detail. Representative areas where tissue identification was critical were removed from half the thickness of the section, and photographs were taken to document orientation relative to the overall specimen. These specimens were embedded in paraffin, sectioned, stained with Mallory trichome stain, mounted on 2 X s-inch glass microscope slides and examined microscopically. A multiparous woman who previously had undergone needle bladder neck suspension at our institution for stress urinary incontinence died several years later of an unrelated illness and was brought in for autopsy. The paraurethral insertion and full course of the suspensory sutures, together with their relationship to the pelvic sidewalls, were studied carefully; this dissection served for comparison with that of the other cadavers in which the presence or absence of stress incontinence

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Levator ani:

Internal urinary

Figure

2. Point

of entry

into

the

space

of

Retzius seen from above. Perforation of the space of Retzius usually occurs lateral to the arcus tendineus fasciae pelvis and superior fascia less frequent the arcus

of the levator ani. site of perforation

tendineus

fasciae

(Inset: medial

the to

pelvis).

uscle and fascia

rcus tendineus

symptoms could not be established. We wanted to ensure that the conclusions based on the cadaver studies were not altered by the absence in the cadavers of the anatomic changes characteristic of stress incontinence. Our surgical experience with needle suspensions, retropubic repairs, and over 200 pelvic dissections provided additional comparative information.

Results The anatomic findings of these dissections are shown in Figures l-4. The avascular plane of vaginal dissection lay between the vaginal mucous membrane and the visceral endopelvic fascia. This fascia consists of the vaginal muscularis and the endopelvic fascia that invests the vagina. The dissection was cephalad to the perineal membrane. The point of entry into the space of Retzius lay in the avascular cleavage space medial to the levator ani muscles and their overlying fascia but lateral to the arcus tendineus fasciae pelvis, the paraurethral vascular plexus (formed by branches of the inferior vesical and vaginal vessels), and bladder neck. It lay cephalad to the perineal membrane.

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The medial relations, from right to left (ie, approaching the midline) of the surgeon’s right index finger inserted transvaginally into the right retropubic space included the perforated and partially detached superior fascia of the levator ani muscles, the arcus tendineus fasciae pelvis, the endopelvic fascia between the vagina and urethra, the paraurethral vascular plexus, and the bladder neck. Lateral to this dissection were the levator ani muscles. Caudal to the surgeon’s finger lay the perineal membrane with the dorsal artery and nerve of the clitoris and the striated urogenital sphincter muscles (compressor urethras and urethrovaginal sphincter) embedded in its substance as well as the pubic bones. The intramural portion of the ureter lay cephalad and medial to this plane of dissection, whereas the obturator nerve and vessels lay cephalad and lateral. There were two groups of blood vessels vulnerable to injury in this dissection: the branches of the inferior vesical and vaginal arteries that form the paraurethral vascular plexus, which lie lateral to the urethra just above the paraurethral sulcus and the branches of the dorsal clitoral vessels that lie in the perineal membrane. The paraurethral vascular plexus lies medial to the plane of dissection; the clitoral vessels are caudal to it.

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Figure 3. Tramvaginal view of suspensory- suture insertion through a pamurethral incision. (Inset: tramabdominal view showing relationship of helical suspensory suture to the paraurethral vascular plexus with the anterior wall of the bladder removed to reveal the internal urinary meatus).

The tissues incorporated in the suspensory suture were identified. They included the portion of the endopelvic fascia that lies between the vagina and urethra, smooth muscle of the vaginal wall, and the arcus tendineus fasciae pelvis. Attachment of these tissues, through the suspensory suture to the rectus sheath, provided resistance to downward descent of the urethra and stabilized the fascial layer on which the urethra rests. It was possible to achieve this level of support without elevating the urethra beyond its normal location.

DiscussioTz This study clarifies the anatomy involved in needle bladder neck suspension operations that require entry to the space of Retzius, emphasizing that the structural effect of the suspensory sutures is the formation of a point of lateral fixation that stabilizes the endopelvic fascia on which the urethra rests. This prevents descent of the urethra during increases in abdominal pressure. In addition, this study clarifies the relationship between the plane of dissection and important structures that may be injured during dissection. The large plexus of blood vessels that lies beside the urethra may be injured if dissection is directed in the vertical plane in an attempt to enter the space of Retzius. Intraoperatively, we have found that a more lateral dissection passing on the inner surface of the

ischiopubic ramus 2-3 cm off the midline is associated with less bleeding and less risk of bladder entry, and these anatomic findings support this point. In addition, more lateral dissection facilitates entry of the space of Retzius between the levator ani and its superior fascia, lateral to the arcus tendineus fasciae pelvis. This is a plane removed from the location of the bladder, even when the patient previously has had a retropubic urethropexy and, therefore, provides an additional margin of safety to the dissection. The dorsal clitoral vessels and their accompanying nerve to the clitoris, lying within the perineal membrane, may be injured if the dissection is made too far caudally in the lower one-third of the urethra. Transvaginal entry of the space of Retzius by perforating the “urogenital diaphragm” (perineal membrane) as described by others4r5 would lead to this complication and is, therefore, unlikely to be an accurate anatomical description of the technique actually employed in the operation. Therefore, entry into the space of Retzius opposite the mid- and upper third of the urethra is preferable. From our cadaveric dissection and surgical experience, transvaginal penetration into the space of Retzius may occur medial to the arcus tendineus fasciae pelvis and levator fascia, and the presence of the arcus explains the palpable band of tissue often discernible along the medial margin of the opening into the space of Retzius. We suspect that lateral perforation, as in our dissection, is more common and may be preferable as it allows these structures to be incorporated into the suspensory suture and is more removed from the bladder neck and its associated vessels. Lateral dissection and suspension also appear less likely to give rise to postoperative irritative and obstructive symptoms6 The dissection to enter the space of Retzius in this study lies within the area where separation of the endopelvic fascia from the arcus tendineus fasciae pelvis occurs. This defect was obvious in the cadaver that previously had undergone needle bladder neck suspension; it has been described during other abdominal dissections7,H and, more recently, using magnetic resonance imaging.’ The mechanical effect that the suspensory sutures produce is best understood by understanding the anatomy of urethral support. The urethra rests on a supportive layer consisting of visceral endopelvic fascia and anterior vaginal wall that is attached to the arcus tendineus fasciae pelvis and the levator ani muscles. The arcus tendineus fasciae pelvis, which extends from a point 1 cm inferior to the lower border of the pubic symphysis to the ischial spine, provides a lateral attachment in its anterior portion for the fascia supporting the urethra. The anterior part of the arcus is a thin tendi-

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-Arcus tendineus fascia pelvis - Levator ani - Pubovesical

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- Periurethral

vessels

-Urethra -Vaginal fascia -Vaginal -Vagina

nous band; it widens posteriorly and becomes less well defined. In the area near the pubis, the arcus tendineus fasciae pelvis lies on the inner surface of the levator ani muscles, which originate from the inner aspect of the pubic bones, 2-4 cm above the arcus. The arcus tendineus levator ani gives attachment to the levator ani muscles and is distinct from the arcus tendineus fasciae pelvis. Although the urethral supports have been termed the posterior pubourethral ligaments, the fascial attachment of the urethra does not insert exclusively into the pubic bone and does not attach directly to the urethra itself.‘” Although Pereyra et al’ emphasized the importance of incorporating posterior pubourethral ligaments in suspensory sutures,” the traditional anatomic description of these urethral supports is at variance with the findings in these dissections and in others performed previously by one of the authors.‘“.” In fact, the urethra is supported by two attachments: a fascia1 attachment that connects the visceral endopelvic fascia between the urethra and vagina to the arcus tendineus fasciae pelvis and a muscular attachment that connects the connective tissue around the vagina to the le\rator ani muscles in this region.” Entry into the space of Retzius just caudal to the bladder neck provides the safest location of entry. The effect of the suspensory suture is to provide a new point of lateral fixation for the endopelvic fascia that lies under the bladder neck. Using a helical loop and incorporating the inner portion of the vaginal wall, as described by Raz, ” adds to the securitv of the suture. In this position the direction of susiension at the bladder neck is directly along the line of the levator nni

endopelvic muscularis

Figure 4. Suspensory suture attachment to the fascia viewed from the space of Retzius, with the urethra and vagina transected at the level of the vesical neck exposing the vaginal and urethral lumens and showing the attachment of the arcus tendineus fasciae pelvis to the pubic bone. The plane of dissection lies between the vaginal mucosa and the combination of the vaginal muscularis and endopelvic fascia which, together, constitute the surgical fascia identified in the operating room and used for support. Inset shows the situation when a paraurethral rather than a midline incision is used.

muscles and also in the direction of the urethral fascial attachment to the arcus tendineus fasciae pelvis. Like most other urethropexies, this type of needle suspension precludes the normal mobility of the bladder neck that occurs with levator contraction and relaxation. However, when properly performed to provide stabilization without hyperelevation, it may provide a relatively normal functional position for the urethra. This technique is well suited to those patients with stress incontinence caused by defective urethral support who have a relatively isolated fascial separation at the level of the bladder neck. The extent of fascial separation can be determined by careful clinical examination.

References I. I%*rry-ra Al. A slmphfied procedure for the correction of stress incontinence in women. West J Surg Obstet Gynecol1959;67:223-6. 1. Karram MM, Bhatia NN. Transvaginal needle bladder neck susp<>nsmn procedures for stress urinary incontinence: A comprehensi\,e rex’le~. Obstet Gynecol 1989;73:906-14. 3. International Anatomical Nomenclature Committee of the International Congress of Anatomists. Nomina anatomica. 5th ed. Baltirnc,re’ Willlams & Wilkins, 1983. 4 Lees DH, Smger A. A colour atlas of gynaecological surgery. Vol. I. I.ondon. Wolfe Medical Publications Ltd, 1978:177-200. 7 Summit jr RL, Bent AE, Ostergard DR, Harris TA. Suburethral ,Img proccdtlre tor genuine stress incontinence and low urethral ;Iosure pre+urt>. A continued experience. Int Urogynecol J 1992; IIS-21. (3. Ra/ S, Su~~m,m EM, Erickson DB, Bregg KJ, Nitti VW. The Raz bl,ldder neck subpension: Results in 206 patients. J Urol 1992;148: ri4i-io. 7 I
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8. Richardson AC, Edmunds PB, Williams NL. Treatment of stress urinary mcontinence due to paravaginal fascial defect. Obstet Gynecol 1981;57:357-62. 9. Klutke V, Golomb J, Barbaric Z. Raz S. The anatomy of stress incontinence: Magnetic resonance imagmg of the female bladder neck and urethra. J Ural 1990;143:563-6 10. DeLancey JOL. fubovesical ligament: A separate structure from the urethral supports (“pubo-urethral ligaments”). Neurourol Urodyn 1989;8:53-61. 11. Pereyra AJ, Lebherz TB, Growden WA, Powers JA. Pubourethral supports in perspective: Modified I’ereyra procedure for urinary mcontinence. Obstet Gynecol lY82;59:64S8. 12. DeLancey JOL. Correlative study of pamurethral anatomy. Obstet Gynecol 1986;68:91-7. 13. DeLancey JOL. The structural support of the urethra as it relates to stress urinary incontmrnce: The “hammock hvpothrsls.” Am J Obstet Gynecol 1994;170:171.?-20. 14. Raz S. Modified bladder neck suspension tar female stress incontinence. Urology 1981;17:82-.I

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Reccioeil Receizmi Acceptd

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Copyright 0 1996 by The Gynecologists.

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]uly 26, 1995.

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