T. Ignacio Montoya

Vascular and ureteral anatomy relative to the midsacral promontory

OBJECTIVE The objective of the study was to further characterize the vascular and ureteral anatomy relative to the midsacral promontory, a landmark often used during sacrocolpopexy, and suggest strategies to avoid complications. STUDY DESIGN Distances between the right ureter, aortic bifurcation, and iliac vessels to the midsacral promontory were examined in 25 unembalmed female cadavers and 100 computed tomography (CT) studies. Data were analyzed using Pearson χ(2), unpaired Student t test, and analysis of covariance. RESULTS The average distance between the midsacral promontory and right ureter was 2.7 cm (range, 1.6-3.8 cm) in cadavers and 2.9 cm (range, 1.7-5.0 cm) on CT (P = .209). The closest cephalad vessel to the promontory was the left common iliac vein, the average distance being 2.7 cm (range, 0.95-4.75 cm) in cadavers and 3.0 cm (range, 1.0-6.1 cm) on CT (P = .289). The closest vessel to the right of the promontory was the internal iliac artery, with the average distance of 2.5 cm (range, 1.4-3.9 cm) in cadavers and 2.2 cm (range, 1.2-3.9 cm) on CT (P = .015). The average distance from the promontory to the aortic bifurcation was 5.3 cm (range, 2.8-9.7 cm) in cadavers and 6.6 cm (range, 3.1-10.1 cm) on CT (P < .001). The average distance from the aortic bifurcation to the inferior margin of the left common iliac vein was 2.3 cm (range, 1.2-3.9 cm) in cadavers and 3.5 cm (range, 1.7-5.6 cm) on CT (P < .001). CONCLUSION The right ureter, right common iliac artery, and left common iliac vein are found within 3 cm from the midsacral promontory. A thorough understanding of the extensive variability in vascular and ureteral anatomy relative to the midsacral promontory should help avoid serious intraoperative complications during sacrocolpopexy.

Anatomic relationships of the pudendal nerve branches

OBJECTIVE We sought to characterize the distribution of the pudendal nerve branches and to correlate findings with injury risk related to common midurethral sling procedures. STUDY DESIGN Dissections were performed in 18 female cadavers. Biopsies were obtained to confirm gross findings by histology. RESULTS In all dissections, most of the clitoral and perineal nerves coursed caudal to the ventral portion of the perineal membrane. The inferior rectal nerve did not enter the pudendal canal in 44% (n = 8) of specimens. Nerve tissue was confirmed histologically in tissue sampled. CONCLUSION The clitoral and perineal branches of the pudendal nerve should be at low risk of direct nerve injury during midurethral slings and similar procedures as they course caudal to the ventral portion of the perineal membrane. The inferior rectal nerve might be at risk of injury during procedures that involve passage of needles through the ischioanal fossa.

Effect of Vaginal or Systemic Estrogen on Dynamics of Collagen Assembly in the Rat Vaginal Wall

ABSTRACT The objective of this study was to compare the effects of systemic and local estrogen treatment on collagen assembly and biomechanical properties of the vaginal wall. Ovariectomized nulliparous rats were treated with estradiol or conjugated equine estrogens (CEEs) either systemically, vaginal CEE, or vaginal placebo cream for 4 wk. Low-dose local CEE treatment resulted in increased vaginal epithelial thickness and significant vaginal growth without uterine hyperplasia. Furthermore, vaginal wall distensibility increased without compromise of maximal force at failure. Systemic estradiol resulted in modest increases in collagen type I with no change in collagen type III mRNA. Low-dose vaginal treatment, however, resulted in dramatic increases in both collagen subtypes whereas moderate and high dose local therapies were less effective. Consistent with the mRNA results, low-dose vaginal estrogen resulted in increased total and cross-linked collagen content. The inverse relationship between vaginal dose and collagen expression may be explained in part by progressive downregulation of estrogen receptor-alpha mRNA with increasing estrogen dose. We conclude that, in this menopausal rat model, local estrogen treatment increased total and cross-linked collagen content and markedly stimulated collagen mRNA expression in an inverse dose-effect relationship. High-dose vaginal estrogen resulted in downregulation of estrogen receptor-alpha and loss of estrogen-induced increases in vaginal collagen. These results may have important clinical implications regarding the use of local vaginal estrogen therapy and its role as an adjunctive treatment in women with loss of vaginal support.

Estrogen Alters Remodeling of the Vaginal Wall after Surgical Injury in Guinea Pigs

ABSTRACT Loss of pelvic organ support (i.e., pelvic organ prolapse) is common in menopausal women. Surgical reconstruction of pelvic organ prolapse is plagued with high failure rates. The objective of this study was to determine the effects of estrogen on biomechanical properties, lysyl oxidase (LOX), collagen content, and histomorphology of the vagina with or without surgical injury. Nulliparous ovariectomized guinea pigs were treated systemically with either 50 μg/kg/day estradiol (E2,) or vehicle. After 2 wk, vaginal surgery was performed, and animals were treated with either beta-aminopropionitrile (BAPN, an irreversible LOX inhibitor), or vehicle to determine the role of LOX in recovery of the vaginal wall from injury with or without E2. Estradiol resulted in (i) significant growth, increased smooth muscle, and increased thickness of the vagina, (ii) increased distensibility without compromise of maximal force at failure, and (iii) increased total and cross-linked collagen. In the absence of E2, BAPN resulted in decreased collagen and vaginal wall strength in the area of the injury. In contrast, in E2-treated animals, increased distensibility, maximal forces, and total collagen were maintained despite BAPN. Interestingly, LOX mRNA was induced dramatically (9.5-fold) in the injured vagina with or without E2 at 4 days. By 21 days, however, LOX levels declined to near baseline in E2-deprived animals. LOX mRNA levels remained strikingly elevated (12-fold) at 21 days in the estrogenized vagina. The results suggest that prolonged E2 induced increases in LOX, and collagen cross-links may act to sustain a matrix environment that optimizes long-term surgical wound healing in the vagina.

Pelvic Organ Support in Animals with Partial Loss of Fibulin-5 in the Vaginal Wall

Compromise of elastic fiber integrity in connective tissues of the pelvic floor is most likely acquired through aging, childbirth-associated injury, and genetic susceptibility. Mouse models of pelvic organ prolapse demonstrate systemic deficiencies in proteins that affect elastogenesis. Prolapse, however, does not occur until several months after birth and is thereby acquired with age or after parturition. To determine the impact of compromised levels of fibulin-5 (Fbln5) during adulthood on pelvic organ support after parturition and elastase-induced injury, tissue-specific conditional knockout (cKO) mice were generated in which doxycycline (dox) treatment results in deletion of Fbln5 in cells that utilize the smooth muscle α actin promoter-driven reverse tetracycline transactivator and tetracycline responsive element-Cre recombinase (i.e., Fbln5f/f/SMA++-rtTA/Cre+, cKO). Fbln5 was decreased significantly in the vagina of cKO mice compared with dox-treated wild type or controls (Fbln5f/f/SMA++-rtTA/Cre-/-). In controls, perineal body length (PBL) and bulge increased significantly after delivery but declined to baseline values within 6–8 weeks. Although overt prolapse did not occur in cKO animals, these transient increases in PBL postpartum were amplified and, unlike controls, parturition-induced increases in PBL (and bulge) did not recover to baseline but remained significantly increased for 12 wks. This lack of recovery from parturition was associated with increased MMP-9 and nondetectable levels of Fbln5 in the postpartum vagina. This predisposition to prolapse was accentuated by injection of elastase into the vaginal wall in which overt prolapse occurred in cKO animals, but rarely in controls. Taken together, our model system in which Fbln5 is conditionally knock-downed in stromal cells of the pelvic floor results in animals that undergo normal elastogenesis during development but lose Fbln5 as adults. The results indicate that vaginal fibulin-5 during development is crucial for baseline pelvic organ support and is also important for protection and recovery from parturition- and elastase-induced prolapse.

Risk factors for ureteral occlusion during transvaginal uterosacral ligament suspension.

Introduction and hypothesisTo determine any risk factors associated with ureteral occlusion during transvaginal uterosacral ligament suspension (USLS).MethodsA retrospective query to identify patients that underwent transvaginal USLS at a teaching hospital from 2008 to 2013 was performed. Patients in which ureteral occlusion was identified by cystoscopy were identified (cases), and compared with those without occlusion (controls). Medical records were reviewed for data abstraction. Variables compared between cases and controls included demographics, medical history/examination, concomitant procedures, number of suspension sutures placed, estimated blood loss and length of hospital stay. Univariate analyses were performed to identify potential risk factors for ureteral occlusion, followed by multivariate regression analysis to estimate odds ratios for identified predictors.ResultsA total of 144 USLS procedures were performed. Thirteen cases of ureteral occlusion were identified (9%). Baseline prolapse stage, body mass index, parity, previous hysterectomy or pelvic surgery of the groups were similar (all P > 0.05). Univariate analysis identified age (P = 0.04), concomitant anterior colporrhaphy (P = 0.01), and use of a suture-capturing device for suture placement (P = 0.04) as significant factors. On multivariate logistic regression analysis, concomitant anterior colporrhaphy increased ureteral occlusion risk (OR 10.5, 95%CI 2.37–74.99, P = 0.001), while use of a suture-capturing device decreased it (OR 0.1, 95%CI 0–0.41, P = 0.01). The mean number of suspension sutures placed per side was similar in the two groups (2.6 [range 2–4] for cases and 2.4 [range 1–4] for controls, P = 0.15).ConclusionsDuring transvaginal USLS, performance of a concomitant anterior colporrhaphy increased the risk of ureteral occlusion, while the use of a suture-capturing device for suspension suture placement was associated with decreased risk.

Apical vaginal prolapse surgery: practice patterns and factors guiding route of repair.

Objectives Describe current trends for repair of primary and recurrent apical vaginal prolapse using 4 different approaches, namely, transvaginal native (TVN) tissue, transvaginal using graft, laparotomy, or laparoscopic/robotic, and to determine which factors influence decision for favored approach. Methods A 15-item survey was distributed to attendees of the 2011 Society of Gynecologic Surgeons meeting. Demographic data and percentages of routes of repair were collected. Twenty factors were graded on the importance for influencing surgical approach. Results Transvaginal native tissue was the preferred route for primary repair (mean, 53.0%), and laparoscopic/robotic for recurrent repair (33.8%). Surgeons in academic practices, without formal postresidency training, and with lower surgical volumes were more likely to elect TVN for primary repair than alternatives. Important factors in selection of surgical approach included patient age and severity of medical comorbidities. Conclusions Among the Society of Gynecologic Surgeons meeting attendees, TVN is the preferred primary route for apical prolapse repair. Laparoscopic-assisted repairs are more common for recurrent prolapse.

Obturator neuropathy after retropubic tension-free vaginal tape placement

BACKGROUND: We report a case of obturator neuropathy associated with retropubic midurethral sling. CASE: After retropubic tension-free vaginal tape (TVT) placement, a 36-year-old woman reported right inguinal region and thigh pain, both exacerbated with internal rotation and adduction. Neurologic examination was remarkable for two-fifths strength with right thigh adduction and an involuntary lateral drift of her right thigh with straight leg raise. Radiologic evaluation was unrevealing. With persistence of motor symptoms and pain, partial sling removal on the right was performed. Symptoms subsided postoperatively, and the patient ultimately recovered with no residual neurologic sequelae. CONCLUSION: Recognition of an atypical complication, obturator neuropathy, of retropubic TVT placement with prompt partial right sling removal on postoperative day 2 resulted in complete recovery of neurologic sequelae.

Functional and anatomic comparison of 2 versus 3 suture placement for uterosacral ligament suspension: a cadaver study.

OBJECTIVE The objective of the study was to compare the vaginal apex pullout distance using 2 vs 3 suspension sutures during transvaginal uterosacral ligament suspension (USLS) and to describe relationships to ipsilateral ureter and nerve structures. STUDY DESIGN Eight fresh-frozen female cadavers were studied. After hysterectomy, a transvaginal USLS was performed with placement of 3 suspension sutures per side. The 2 most distal sutures on each ligament were tied. A screw-and-washer attachment was secured in the middle of the vaginal cuff and tied to a pulley system with surgical filament. Distal traction was applied with sequentially increasing weight loads. Distal migration of the vaginal apex from baseline with each weight load was recorded. The most proximal suspension suture was tied and the procedure repeated. Horizontal distances between each USLS suture to the ipsilateral ureter were measured. Three discrete points were marked on sacral nerves S1-S3, and the shortest distance between each point and each ipsilateral USLS suture was measured. Descriptive statistics and repeated-measures analysis of variance were performed. RESULTS Application of each load resulted in greater migration distances for the 2 suture configuration when compared with 3 sutures (P < .05). Differences were greatest for the 3 kg load (mean ± SEM, 2.0 ± 0.2 vs 1.5 ± 0.1 cm, respectively). Distances to ipsilateral ureter between the 2 most cranial sutures were comparable (P > .05). The most cranial USLS suture was closest to sacral nerves S1-S3. CONCLUSION In this cadaveric study, 3 USLS sutures provided more support to the vaginal apex than 2 sutures, although the absolute difference may not be clinically significant. The most cranial suture had the smallest distances to sacral nerves S1-S3.

Thermosensitive hydrogels deliver bioactive protein to the vaginal wall.

The pathophysiology and natural history of pelvic organ prolapse (POP) are poorly understood. Consequently, our approaches to treatment of POP are limited. Alterations in the extracellular matrix components of pelvic support ligaments and vaginal tissue, including collagen and elastin, have been associated with the development of POP in animals and women. Prior studies have shown the protease MMP-9, a key player of ECM degradation, is upregulated in vaginal tissues from both mice and women with POP. On the other hand, fibulin-5, an elastogenic organizer, has been found to inhibit MMP-9 in the vaginal wall. Hence, we hypothesized that prolonged release of fibulin-5 may delay progression of POP. To test the hypothesis, oligo (ethylene glycol)-based thermosensitive hydrogels were fabricated, characterized and then used to deliver fibulin-5 to the vaginal wall and inhibit MMP-9 activity. The results indicate that hydrogels are cell and tissue compatible. The hydrogels also prolong the ½ life of fibulin-5 in cultured vaginal fibroblasts and in the vaginal wall in vivo. Finally, fibulin-5-containing hydrogels resulted in incorporation of fibulin-5 into the vaginal matrix and inhibition of MMP-9 for several weeks after injection. These results support the idea of fibulin-5 releasing hydrogel being developed as a new treatment for POP.