Sacrospinous Ligament and Iliococcygeus Muscle Suspensions
J. Eric Jelovsek
Sacrospinous ligament fixation (or “suspension”) and iliococcygeus muscle suspension are common vaginal approaches for resuspending the apical or upper vagina in women with pelvic organ prolapse. They are a core part of the armamentarium of the vaginal surgeon because they allow the surgeon to resupport the vagina and do not necessarily require entry into the peritoneal cavity. Both procedures can be simultaneously performed with other procedures including hysterectomy, anterior colporrhaphy, posterior colporrhaphy, enterocele sac repair using peritoneal closures, modified Moschcowitz, or modified McCall culdoplasty.1
SACROSPINOUS LIGAMENT SUSPENSION
Sacrospinous and sacrotuberous ligament fixations were introduced in Europe by Zwiefel, possibly as early as 1892. Sacrospinous ligament fixation was subsequently described by Amreich in 1950 and then modified by Richter in 1968.2,3 In the United States, enthusiasm for the procedure progressed as a common option for correction of apical vaginal prolapse after 1971 when Randall and Nichols reported on a series of 18 patients.3
The ischial spines are an important bilateral landmark and reference point for various female pelvic reconstructive surgeries. In the upright woman, the ischial spine is a bony projection located at the level of the pubic symphysis that projects posteriorly toward the sacrum. In lithotomy, the ischial spine can be easily palpated during pelvic or rectal exam. It separates the superior greater sciatic notch and the inferior lesser sciatic notch. The sacrospinous ligament has a triangular shape. The apex of the sacrospinous ligament attaches to the ischial spine and the wider base attaches broadly to the lower sacrum and coccyx. An Elementary Treatise on Anatomy (1837) describes the ligament as “a strong, flattened, vertical fasciculus, fixed on one side to the posterior-superior spine of the os ilium, and on the other to the lateral and posterior parts of the sacrum, on a level with the third sacral foramen.”4 The presence of the ligament results in the greater sciatic foramen which contains the gluteal and thigh vessels and nerves and the piriformis muscle. The inferior gluteal and the internal pudendal arteries arise from the internal iliac artery and exit through the greater sciatic foramen closest to the top of the sacrospinous ligament.5,6 The pudendal nerve arises from sacral nerves S2, S3, and S4 and exits the greater sciatic foramen and travels through the ischioanal fossa where it branches anteriorly to innervate the perineum and posteriorly to innervate portions of the external anal sphincter. The pudendal nerves and vessels lie immediately posterior to the ischial spine, whereas the sciatic nerve is superior and lateral to the sacrospinous ligament. The nerve to coccygeus muscle arises from contributions from S3, S4, or S5 and pierces the sacrospinous ligament to reach the underlying coccygeus muscle. The nerve to levator ani muscle also arises from contributions from S3, S4, or S5 and courses over the cephalad surface of the sacrospinous ligament and give off branches to innervate iliococcygeus, pubococcygeus, and the puborectalis muscles (Fig. 48.1).
The levator ani muscles originate from a linear thickening musculofascial attachment covering the obturator internus muscle called the arcus tendinous levator ani which runs from the ischial spine to the posterior surface of the ipsilateral pubic ramus. The levator ani muscle consists of the puborectalis, pubococcygeus, and iliococcygeus muscle. This muscle’s posterior boundary is the ischial spine.
Sacrospinous ligament suspension
The sacrospinous ligament suspension is a popular transvaginal approach to manage posthysterectomy apical prolapse and can be performed with simultaneous hysterectomy or as a hysteropexy. It is most commonly performed by suspending the vaginal apex to the right sacrospinous ligament but can be easily performed using the woman’s left sacrospinous ligament or bilaterally. The Michigan four-wall suspension described by Morely and DeLancey7 is a modification of the original description and emphasizes the excision of excess vaginal length from the anterior, posterior, and lateral vaginal walls to prevent laxity between the suspension point at the sacrospinous ligament and the introitus.
Prior to performing a sacrospinous ligament suspension, the surgeon should be familiar with relevant pelvic anatomy including the perirectal space and ischioanal fossa. The technique is as follows:
Pelvic examination should be performed to identify the ischial spines.
It is often useful to determine whether the prolapsed vaginal apex will easily reach the sacrospinous ligament by manually reducing the prolapse to the targeted suspension site. This can be accomplished by bilaterally grasping the apex of the vagina using two or more Allis clamps. In order to obtain a more
symmetric repair, the surgeon can shift the “new” vaginal apex anteriorly for anterior wall-predominate apical prolapse or posteriorly for posterior wall-predominate prolapse. This attachment site can be tagged with suture for future identification.
There are two main approaches to the sacrospinous ligament fixation: posterior and anterior approach. In the posterior approach, the posterior vaginal wall is incised in the midline and ends approximately 1 to 2 cm before the vaginal apex. If an enterocele is encountered, some surgeons will dissect this sac away from the rectum, enter the peritoneum, and occlude the enterocele sac using pursestring suture. Kearney and DeLancey8 reported that a diamond-shaped incision is performed posterior to the hysterectomy scar in 75% of patients undergoing a Michigan four-wall suspension.
Dissection begins into the perirectal space on the ipsilateral side of the anticipated suspension. This is usually performed using blunt dissection and facilitated while retracting the rectum medially and the bladder gently retracted upward often accomplished using one or two Breisky-Navratil vaginal retractors. Recurrent palpation of the ischial spine helps facilitate appropriate location during dissection.
FIGURE 48.2 A-C: Approximate suture attachment location when performing sacrospinous ligament suspension or fixation.
Dissection should proceed until the ischial spine is identified. Blunt dissection may be used in a lateral to medial fashion to expose the surface of the sacrospinous ligament.
There are several techniques to pass sutures into the sacrospinous. Many surgeons use the Capio suture-capturing device to pass suture. The Michigan four-wall suspension that uses a Deschamps ligature carrier and others perform fixation using a Miya hook.9,10 In our practice, we prefer the ease of placing the end of the Capio ligature carrier on the surface of the ligament. Prior to passing suture, the rectum should be retracted medially, and caution should be used in retracting the vaginal walls superiorly to prevent neurovascular damage. The left hand should palpate the right ischial spine. Holding the suture-passing device in the right hand, the notch should be placed at the middle (approximately 3 cm from ischial spine) of the sacrospinous ligament and held firmly in place using the finger of the opposing hand. With continued downward pressure, the suture is passed using the device, the device removed, and the suture tagged to the side for later use. In our practice, we place two to four sutures in the middle portion of the ligament (Fig. 48.2). There is currently
a lack of consensus on the optimal number and location of sutures placed during sacrospinous ligament fixation.11 It is possible to place sutures as far laterally as the lateral third of the ligament closest to the ischial spine and as far medially as the medial third of the ligament closest to the sacrum. Cadaveric studies suggest that the middle segment of the sacrospinous ligament has the lowest incidence of nerves and arteries located there.11
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