Three-dimensional transperineal ultrasound for imaging mesh implants following sacrocolpopexy

Ultrasound Obstet Gynecol 2014; 43: 459 465 Published online in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/uog.13303 Three-dimensional transperineal ultrasound for imaging mesh implants following sacrocolpopexy V. H. EISENBERG*, M. STEINBERG, Z. WEINER, M. ALCALAY*, J. ITSKOVITZ-ELDOR, E. SCHIFF* and L. LOWENSTEIN *Department of Obstetrics and Gynecology, Sheba Medical Center, Tel Hashomer, Israel; Department of Obstetrics and Gynecology, Rambam Health Care Campus, Haifa, Israel KEYWORDS: 3D transperineal ultrasound; cystocele; mesh; mesh folding; pelvic organ prolapse; sacrocolpopexy ABSTRACT Objective To characterize, using three-dimensional (3D) transperineal ultrasound, the appearance, position and dimensions of mesh implants following minimally invasive abdominal sacrocolpopexy. Methods In women who underwent sacrocolpopexy, mesh was evaluated at rest and on maximal Valsalva, on all 3D orthogonal planes and rendered views. Mesh dimensions were obtained by 3D processing in the midsagittal and coronal planes (anterior, posterior and sacral arm) and were analyzed offline, the operator blinded to clinical data. Results Overall, 62 women, mean age 58.4 (range, 42 79) years were evaluated at a median of 9 (range, 1 26) months following surgery. The anterior arm of the mesh was caudal to the lowermost point of descent of the anterior compartment in 56 (90.3%) women, was equally positioned in five (8.1%) and was cranial in one. The posterior arm was caudal in 44 (71%) women, was equally positioned in 16 (25.8%) and was cranial in two (3.2%). The Y connection and the sacral arm of the mesh could not be adequately seen because of physical limitations of ultrasound (lower resolution at greater depth), large recurrent rectoceles, echogenic stools or folding of mesh remnants. Folding of the mesh was seen in 46 (74.2%) women, folding of the anterior arm in five (8.1%) and folding of the posterior arm in 23 (37.1%). Folding occurred caudally in 26 (41.9%) women, proximally in 11 (17.7%) and in both areas in nine (14.5%). There were no erosions. Conclusion Mesh visualization following minimally invasive abdominal sacrocolpopexy procedures using transperineal 3D/four-dimensional (4D) ultrasound is feasible. Studies are needed to evaluate the correlation between ultrasound measures and prolapse recurrence or mesh erosion. Copyright 2014 ISUOG. Published by John Wiley & Sons Ltd. INTRODUCTION Abdominal sacrocolpopexy is considered as the goldstandard procedure for surgical management of apical prolapse, with high long-term success rates 1 and a number of access routes (abdominal, laparoscopic and robotic). Since the first case series of 15 patients who underwent laparoscopic sacrocolpopexy, described by Nezhat et al. 2, the technique has acquired increasing acceptance among pelvic floor surgeons. Nevertheless, despite the advantages of laparoscopic surgery, the adoption of laparoscopic sacrocolpopexy is still limited, mainly because of the advanced surgical skills required. The introduction, in 2005, of robotic-assisted surgery presented an opportunity to perform sacrocolpopexy using a minimally invasive approach with a relatively rapid learning curve. In 2011 the Food and Drug Administration (FDA) issued its second safety communication regarding mesh surgery. Between 2008 and 2010, the complications most frequently reported to the FDA from the use of surgical mesh devices for pelvic organ prolapse (POP) repair included vaginal mesh erosion, dyspareunia, infections and urinary problems. Owing to the relatively high complication rate and secondary to recent FDA warnings, many gynecologists have become hesitant to offer permanent vaginal mesh for POP, and are more likely to offer robotic, laparoscopic or abdominal sacrocolpopexy for women with apical prolapse repair. Traditionally, recurrence rates of prolapse, symptomatology and adverse events are the main outcome measures used to evaluate surgical success following minimally invasive sacrocolpopexy 3,4. Transperineal ultrasound has become an effective tool for the clinical assessment of pelvic floor dysfunction 5 8. Ultrasound is the method of choice for imaging mesh implants, mainly because of the highly echogenic characteristic of polypropylene meshes, which hinders clear imaging with X-ray, computed tomography (CT) or magnetic resonance imaging (MRI). Previous studies Correspondence to: Dr V. H. Eisenberg, Sheba Medical Center, Tel Hashomer, Ramat Gan, 52621, Israel (e-mail: veredeis@bezeqint.net) Accepted: 30 December 2013 Copyright 2014 ISUOG. Published by John Wiley & Sons Ltd. ORIGINAL PAPER

460 Eisenberg et al. that used ultrasound to evaluate the appearance of polypropylene mesh following vaginal procedures focused on the significance of mesh shrinkage and folding 9,10. Our primary aims were to investigate the feasibility of three-dimensional (3D) and four-dimensional (4D) ultrasound in the evaluation of minimally invasive abdominal sacrocolpopexy procedures, and to characterize the pelvic anatomy and mesh implant topography in relation to pelvic organs. Our secondary aims were to assess prolapse recurrence, and mesh shrinkage and folding after these procedures. METHODS The Research Ethics Institutional Review Committee of Rambam Health Care Campus approved the study protocol. Eighty-three women who underwent laparoscopic and robotic sacrocolpopexy at our tertiary-care referral center between June 2009 and October 2012 were invited to participate in the study as part of a retrospective audit. Informed consent was obtained from all participants. All laparoscopic and robotic surgeries were performed by a single urogynecology-trained surgeon (L.L.). Robotic sacrocolpopexy was performed using the da Vinci Surgical System (Intuitive Surgical Inc., Sunnyvale, CA, USA), and laparoscopic procedures were performed using a similar technique. In women with uterovaginal prolapse, a supracervical hysterectomy was performed, with or without bilateral salpingo-oophorectomy, as indicated. This was followed by a blunt dissection at the vesicovaginal and rectovaginal spaces, separating the cervix and the vaginal wall from the bladder and rectum, respectively. The tissue overlying the sacral promontory was dissected to expose the anterior longitudinal ligament of the sacrum, taking care to avoid the middle sacral vessels. This was followed by laparoscopic insertion of an ALYTE Y-Mesh Graft polypropylene mesh (BARD Medical Division, Covington, GA, USA) (Figure 1). The mesh consists of two single-knit vaginal flaps and one dual-knit sacral flap, in a Y shape; however, its length can be further tailored to the patient without mesh unraveling. The original dimensions of the mesh are a total of 27 cm in length; and the anterior, posterior and sacral arms are 4 cm in width. The mesh was sutured in place along the anterior and posterior vaginal walls and the vaginal apex/cervix, using non-dissolvable polyester 2.0 sutures (TiCron ; Tyco, Waltham, MA, USA), without tension. Transverse mesh dimensions were not altered. The cranial aspect of the mesh was secured to the sacral promontory with three to four 5-mm tackers (ProTack; Tyco Healthcare, Norwalk, CT, USA), without tension. Following completion of the sacrocolpopexy, additional concomitant procedures were performed as indicated: posterior colpoperineorrhaphy, anterior colporrhaphy and midurethral slings for stress urinary incontinence. The postoperative audit evaluation included the Pelvic Floor Distress Inventory questionnaire (PFDI- 20) 11. Responses to the Urinary Distress Inventory Figure 1 ALYTE Y-Mesh Graft polypropylene mesh (BARD Medical Division, Covington, GA, USA). The mesh consists of two single-knit vaginal flaps and one dual-knit sacral flap, in a Y shape. Mesh dimensions are a total of 27 cm in length from end to end. The width of the anterior, posterior and sacral arms is 4 cm. (UDI-6), the Colorectal Anal Distress Inventory (CRADI- 8) and the Pelvic Organ Prolapse Distress Inventory (POPDI-6) subscales of the PFDI-20 were scored from 0 to 100 according to standard scoring, with higher scores indicating more severe symptoms 11. Clinical demographic data and data regarding the surgery, including concomitant procedures, were retrieved from patients electronic charts. Patients were also asked to grade their satisfaction with surgery on a scale of 1 10. The clinical examination was performed after voiding, with patients in the dorsal lithotomy position with hips flexed and slightly abducted. Clinical examination included the measurement (in cm) of nine locations in the vagina and vulva relative to the hymen, using the prolapse quantification system of the International Continence Society (ICS) Pelvic Organ Prolapse Quantification System (POP-Q) 12. Prolapse recurrence was defined as a cystocele, rectocele or cervical/apical prolapse of Stage 2 or above, based on this classification. Pelvic floor imaging was performed with 3D/4D transperineal ultrasound, using a Voluson 730 ultrasound system (GE Kretz Medical Ultrasound, Zipf, Austria) with a 4 8-MHz RAB curved array volume transducer (acquisition angle = 85 ). Volume acquisition was performed at rest, maximal Valsalva maneuver and maximal pelvic floor contraction, as described by Dietz et al. 6. Care was taken to minimize probe pressure, so as not to reduce maximal descent. The ultrasound operator (V.H.E.) was blinded to the clinical data. Postprocessing analysis of ultrasound volume datasets was performed offline at a later date, using the proprietary software GE Kretz 4D View (GE Medical Systems) for mesh parameters, measurements and dimensions, for prolapse recurrence and for folding, again with blinding to the clinical data. Mesh location and maximal descent on ultrasound were measured relative to the inferior margin of the symphysis pubis (SP) 13 and the most caudal mesh margin

Mesh visualization using 3D transperineal ultrasound 461 was determined in relation to this line. The position of the mesh in relation to the bladder neck was measured craniocaudally (Figure 2). Mesh dimensions were determined at rest by 3D processing in the midsagittal and coronal planes (Figure 3). The anterior and posterior arms were seen in these planes and their visualization was determined as adequate or partial depending on appearance. In order to adequately visualize all mesh arms, the 3D volume included a wide angle and low depth. This enabled the entire visualizable mesh arm to be viewed in one volume, whereas the volume had to be further manipulated to view each arm separately. The urinary bladder was regarded as the anterior landmark for mesh position and the bladder neck was regarded as the craniocaudal landmark. The anterior rectal wall was considered as the landmark for posterior mesh position. Mesh extremities were considered to be those where the typical echogenic mesh appearance could no longer be seen. Volume manipulation was performed as follows: first the rendered box (the region of interest) was rotated and placed in the location of the mesh with the green line curved so that it was slightly above the mesh, as seen in Figure 3. The box dimensions were then adjusted to include the entire mesh arm. This maneuver enabled mesh visualization of the visualizable portions of the anterior and posterior arms. Measurements were then undertaken along the observed mesh extremes at rest. Length was measured craniocaudally with the tracer. Minimal and maximal mesh dimensions were taken along the minimal and maximal observed mesh widths with the tracer. Measurements were taken only along the parts of the mesh that could be identified. Significant prolapse recurrence on ultrasound was defined as bladder descent of 10 mm below the SP on maximal Valsalva for cystocele, descent to the SP on Valsalva for cuff prolapse or enterocele and descent of 15 mm below the SP for rectocele. Folding was defined as mesh folded over at the extremities of the mesh arms. This occured only with the distal aspects of mesh implants where mesh was not anchored to surrounding tissue. Data analysis was performed with SPSS for Windows (SPSS, Inc., Chicago, IL, USA). Continuous parameters were checked for normality by Kolmogorov Smirnov testing. We used intraclass correlations (single measures, absolute agreement definition) for repeatability testing. The independent Student s t-test and the chi-square test were used for comparison between continuous and categorical values, respectively. Pearson correlation was used to test for the effect of time from surgery and mesh dimensions. Multivariable linear regression analysis was used for defining the independent factors that affect the length of the mesh arms. All tests were considered significant at the P < 0.05 level, and were two-sided. RESULTS Overall, 62 (74.7%) of 83 patients accepted the invitation and attended. Twenty-one patients were not available for the specific session dates on which the study Figure 2 Two-dimensional (2D) ultrasound images depicting mesh location and maximum descent, measured relative to the inferior margin of the symphysis pubis. (a) At rest. (b) On Valsalva. Small arrows show the visible anterior mesh arm and large arrows show the posterior mesh arm. The measurements depict (from left to right): bladder neck distance; vaginal cuff distance; anterior mesh lower-most point distance; posterior mesh lower-most point distance; and rectum distance. Measurements are in centimeters. ANT, anterior; BN, bladder neck; CR, cranial; L, levator; POST, posterior; R, rectum; SP, symphysis pubis; V, vaginal cuff. was performed and therefore were not included. The mean age was 58.4 (range, 42 79) years, mean body mass index (BMI) was 26 (range, 18.3 33.8), median parity was 3 (range, 1 9), 11 (17.7%) patients had had a previous hysterectomy and five had undergone previous incontinence surgery. Thirty-four patients had undergone additional concomitant procedures: three had received tension-free vaginal tape (TVT, Gynecare, Johnson & Johnson), 17 had received TVT-obturator (TVT-O, Gynecare, Johnson & Johnson), six had received anterior colporrhaphy and eight had received posterior colporrhaphy. The mean follow-up time from surgery was 9.2 (range, 1 26) months. The mean satisfaction level on a scale of 1 10 was 8.86 ± 1.67. Based on the PFDI-20 questionnaire, the mean ± SD POPDI-6 score was 12.9 ± 15.0 (range, 0 75); five (8.1%) women complained of a vaginal bulge and four (6.5%)

462 Eisenberg et al. Figure 3 Three-dimensional (3D) rendering images of the sacrocolpopexy mesh in the same patient: (a) anterior arm and (b) posterior arm. Arrows indicate mesh location and visible borders are measured (longitudinal, maximal and minimal widths, and sacral arm width). A, anterior; BN, bladder neck; CA, caudal; CR, cranial; L, levator; P, posterior; R, rectum; V, vagina. complained of a rectal bulge. The mean ± SD score on the CRADI-8 was 15.06 ± 16.50 (range, 0 71.88); 24 (38.7%) had flatus incontinence, two (3.2%) had fecal incontinence and 24 (38.7%) complained of difficulty in defecation. The mean ± SD score on the UDI-6 was 20.9 ± 21.7 (range, 0 96); 22 (35.5%) had urinary frequency, 18 (29.0%) had urgency incontinence, 24 (38.7%) had stress incontinence and 11 (17.7%) had voiding difficulty. Objective prolapse recurrence (ICS POP-Q Stage 2 or higher) was observed in six (9.7%) women, but only one complained of a vaginal bulge. On transperineal

Mesh visualization using 3D transperineal ultrasound 463 Table 1 Repeatability calculation for parameters of mesh dimensions obtained by a single operator from stored three-dimensional transperineal ultrasound volumes Dimension Measurement 1 (cm) Measurement 2 (cm) ICC 95% CI P Anterior arm Length 4.07 ± 1.09 4.09 ± 0.95 0.974 0.854 to 0.996 < 0.001 Maximal width 3.38 ± 0.45 3.52 ± 0.60 0.601 0.20 to 0.91 0.06 Minimal width 1.69 ± 0.44 1.75 ± 0.59 0.807 0.219 to 0.97 0.008 Posterior arm Length 4.34 ± 1.07 4.5 ± 1.03 0.968 0.823 to 0.995 < 0.001 Maximal width 3.34 ± 0.88 3.36 ± 0.86 0.971 0.841 to 0.99 < 0.001 Minimal width 1.73 ± 0.63 1.75 ± 0.59 0.971 0.83 to 0.99 < 0.001 Measurements are given as mean ± SD (n = 6). ICC, intraclass correlation coefficient (absolute agreement definition, single measures). ultrasound a significant rectocele was observed in nine women, two of whom also had a significant cystocele. Only two of the women with rectocele on ultrasound actually had a clinically significant Stage 2 rectocele. None had a central compartment prolapse and none required repeat surgery during the follow-up period. There were no clinical erosions. Intraobserver repeatability data (n = 6), performed at different time points, showed moderate to excellent repeatability for measures of mesh dimensions (V.H.E., Table 1). Visualization with ultrasound was clear for all patients, and volumes were readily available for postprocessing (Figure 2). The volumes were manipulated, as described in the Methods, with the stated landmarks. It was not possible to visualize the entire mesh in one volume at the same time in the same plane, or to see the Y intersection, because of the physical limitations of the ultrasound beam. Further difficulty was encountered as a result of the presence of large recurrent rectoceles, echogenic stools or from folding of mesh remnants. The volumes had to be manipulated to allow visualization of the anterior and posterior mesh arms separately. The mesh dimensions were measured for each arm separately along the parts of the mesh that could be seen. We thus had to consider the vaginal cuff to be the caudal end of the mesh arms. Table 2 depicts mesh position and descent on Valsalva, showing the location of the lowermost mesh position for the anterior and posterior arms. Location of the anterior compartment (AC) and the posterior compartment(pc)onvalsalvainrelationtothemesh were also noted (above = cranial, equal, below = caudal). For 56 (90.3%) the anterior mesh was caudal to the lowermost point of descent of the anterior compartment, for five (8.1%) the mesh was equally positioned and for one the mesh was cranial. For the posterior mesh arm the mesh was caudal in 44 (71.0%), equally positioned in 16 (25.8%) and cranial in two (3.2%). Mesh position relative to the bladder neck in the craniocaudal aspect is described in Table 2. Table 3 presents the dimensions of the visible portions of the anterior and posterior arms of the mesh: length, and minimal and maximal widths. Figure 3 depicts mesh appearance on 3D volumes postprocessing of the anterior (Figure 3a) and posterior (Figure 3b) arms. Folding of the mesh was seen in 46 (74.2%) women. Folding of the anterior arm of the mesh was seen in five Table 2 Mesh position and descent on Valsalva and mesh position relative to the bladder neck craniocaudally (n = 62) Measurement (mm) Variable Minimum Maximum Mean ± SD Anterior mesh Rest 46.5 3.4 23.55 ± 9.14 Valsalva 38.3 15.0 3.53 ± 10.58 Descent 4.2 47.7 19.77 ± 9.74 Posterior mesh Rest 24.0 4.3 9.29 ± 5.87 Valsalva 8.2 25.0 4.57 ± 5.85 Descent 1.0 31.9 13.86 ± 7.19 Anterior mesh to BN Rest 20.4 17.7 2.17 ± 8.88 Valsalva 11.0 21.7 7.57 ± 6.60 Lowermost point of mesh from bladder neck (BN). Negative sign indicates above/cranial to point of reference. Table 3 Mesh dimensions (n = 62) as seen on three-dimensional (3D) volume rendering Dimension Mean ± SD (cm) Range (cm) Anterior arm Length 3.59 ± 1.19 1.39 5.96 Maximal width 3.47 ± 0.5 1.67 3.99 Minimal width 2.27 ± 0.67 0.74 3.44 Posterior arm Length 4.18 ± 1.22 1.72 7.01 Maximal width 3.26 ± 0.57 1.80 4.02 Minimal width 2.00 ± 0.66 0.80 3.35 (8.1%), of the posterior arm of the mesh in 23 (37.1%) and folding of both arms in 18 (29%). In 26 (41.9%) cases, folding occurred caudally near the introitus for the posterior arm and near the bladder neck for the anterior arm; a more proximal folding was seen in 11 (17.7%) cases and folding in both areas in nine (14.5%). Shorter mesh dimensions were correlated with greater time lapse from surgery (Table 4). In order to identify independent factors that affect the span of the mesh over the vaginal wall, a linear regression was performed. We used backward linear regression analysis and our final model included time elapsed since surgery, BMI, POP-Q stage and the presence of mesh folding. The duration of

464 Eisenberg et al. Table 4 Correlation between time elapsed since surgery and mesh dimensions Measure Pearson correlation for time since surgery P Coefficient Beta 95% CI Logistic regression for factors affecting mesh dimensions Regression significance Anterior arm Length 0.473 <0.001 Time 0.474 0.128 to 0.045 <0.001 BMI 0.229 0.000 to 0.181 0.049 Maximal width 0.423 <0.001 Time 0.344 0.045 to 0.009 <0.001 POP-Q 0.338 0.426 to 0.079 0.005 Minimal width 0.250 0.028 Time 0.244 0.050 to 0.001 <0.001 Posterior arm Length 0.439 <0.001 Time 0.439 0.129 to 0.038 0.001 Maximal width 0.355 0.003 Time 0.305 0.048 to 0.005 0.018 POP-Q 0.215 0.392 to 0.030 0.091 Minimal width 0.320 0.007 Time 0.320 0.056 to 0.007 <0.001 Pearson correlation, bivariate, all significance is two-tailed. Note the minus symbol in some numbers, indicating an inverse relationship. Backward logistic regression analysis was performed for factors affecting mesh dimensions. The model includes time since surgery (Time), body mass index (BMI), Pelvic Organ Prolapse Quantification System (POP-Q) stage and the presence of folding. The results of significant factors affecting each parameter are shown. time since surgery (inversely affecting mesh dimensions) and BMI were found to be the only significant independent factors that were associated with anterior mesh length (beta = 0.474, P < 0.001 and beta = 0.229, P = 0.049, respectively), whereas only time affected posterior mesh length (beta = 0.439, P = 0.001). POP-Q stage was found to affect independently the anterior and posterior arm maximal widths. All mesh dimensions decreased as time from surgery increased. Folding seemed to reduce the minimal widths of both the anterior and posterior arms, suggesting that folding may affect transverse mesh dimensions; however, this was not statistically significant. Age, duration of surgery, measurements of mesh position (relative to the SP) and mesh descent were not associated with significant differences in mesh dimensions. DISCUSSION The use of mesh to avoid prolapse recurrence in pelvic reconstructive surgery has increased over the last decade. Alongside this increase, major controversy has arisen concerning mesh complications, such as chronic pelvic pain and mesh erosion 14. The upshot of this is an increase in the incidence of minimally invasive abdominal surgery. To the best of our knowledge, this is the first study to describe the use of transperineal ultrasound for the visualization of abdominally inserted mesh implants. Ultrasound is the method of choice for imaging mesh implants, mainly because of the highly echogenic characteristic of polypropylene meshes, which hinders clear imaging with X-ray, CT or MRI 15. Previous studies that used ultrasound to evaluate the appearance of polypropylene mesh following vaginal procedures focused on the significance of mesh shrinkage and folding 9,10. The inverse correlation demonstrated in the current study between mesh dimensions and time from surgery concurs with previously documented observations. On imaging, mesh has been shown to appear folded or contracted following surgery, with smaller dimensions than before surgery 10. This may also be due to wound contraction as part of physiological healing during the period immediately following surgery 9,16. The decrease in mesh dimensions shown in the current study is congruent to that observed in other studies of vaginal surgery 15,16. Mesh folding seems to be a significant feature of the immediate and later postoperative period. The significance of mesh folding following pelvic floor surgery via the abdominal route is still unknown. Although previous researchers associated vaginal mesh folding with an increased risk of mesh erosion, we did not observe any clinical erosion to support this in our study. Ultrasound is an inexpensive, readily available imaging tool that is well accepted by patients. This study shows that ultrasound may aid the clinician in evaluating prolapse recurrence 17,18 or in the assessment of mesh shrinkage or folding 15,16. However, we must acknowledge several limitations of our study. The retrospective and cross-sectional design is one limitation. All our measurements derived from a single follow-up evaluation and therefore cannot provide definite longitudinal conclusions, which would be ideal to monitor variation in mesh length. In future studies, long-term follow-up with evaluation at different stages is recommended. Longer observation periods may elucidate the impact of folding or shrinkage of mesh. Nevertheless, the performance of all procedures by a single surgeon is a strength of this study, as it mitigates the bias that arises from the performance of different operating techniques. Our patient population was demographically Caucasian and there was no ethnic variation, and our results may not be applicable to other populations. Mesh visualization is challenging and requires significant effort and experience in volume manipulation. It is not possible to see the entire Y structure simultaneously as the arms are in different planes, thus falling prey to the physical limitations of ultrasound. However, as mentioned, volume manipulation allows separate analysis of

Mesh visualization using 3D transperineal ultrasound 465 the anterior and posterior arms. The Y intersection lies on the vaginal cuff and is transected by the ultrasound beam. The sacral arm is often too far from the transducer and cannot be reached as a result of low beam penetration. These limitations prevented us from defining the entire landmarks of the Y mesh, but were consistently present in all cases. Additionally, the length of the mesh was affected by tailoring of the arms during surgery and this factor resulted in variation in mesh measurements among patients. However, again this was a consistent finding in all patients and is not likely to present significant bias. Also, we could not report interobserver variation as there was only one observer in this study with 3D manipulation capabilities, but intraobserver repeatability was adequate. Recurrence of clinical prolapse was infrequent in this study. Whether this is because of the limited study period or the abdominal approach is unknown. The significance of prolapse recurrence on ultrasound, in the absence of clinically diagnosed prolapse or prolapse complaints, is not yet clear. As mentioned before, longer observation periods may answer this question. In conclusion, transperineal ultrasound demonstrated effectiveness in mesh evaluation and auditing following minimally invasive abdominal sacrocolpopexy procedures. It enables reproducible measurements of mesh position and dimensions and can be used in a prospective manner to compare mesh dimensions over time after surgery. Mesh folding was a common finding following surgery and may explain the decrease in mesh dimensions observed with time from surgery. Future long-term follow-up is needed in order to correlate between postoperative sonographic findings and clinical findings, such as prolapse recurrence and mesh erosion, in order to ascertain whether mesh shortening occurs as a result of folding or shrinkage. REFERENCES 1. Nygaard IE, McCreery R, Brubaker L, Connolly A, Cundiff G, Weber AM, Zyczynski H; Pelvic Floor Disorders Network. Abdominal sacrocolpopexy: a comprehensive review. Obstet Gynecol 2004; 104: 805 823. 2. Nezhat CH, Nezhat F, Nezhat C. Laparoscopic sacral colpopexy for vaginal vault prolapse. Obstet Gynecol 1994; 84: 885 888. 3. Paraiso MF, Jelovsek JE, Frick A, Chen CC, Barber MD. Laparoscopic compared with robotic sacrocolpopexy for vaginal prolapse: a randomized controlled trial. Obstet Gynecol 2011; 118: 1005 1013. 4. Elliott DS, Krambeck AE, Chow GK. Long-term results of robotic assisted laparoscopic sacrocolpopexy for the treatment of high grade vaginal vault prolapse. J Urol 2006; 176: 655 659. 5. Dietz HP. Pelvic floor ultrasound in prolapse: what s in it for the surgeon? Int Urogynecol J 2011; 22: 221 232. 6. Dietz HP. Ultrasound imaging of the pelvic floor. Part II: threedimensional or volume imaging. Ultrasound Obstet Gynecol 2004; 23: 615 625. 7. Dietz HP. Why pelvic floor surgeons should utilize ultrasound imaging. Ultrasound Obstet Gynecol 2006; 28: 629 634. 8. Dietz HP. Pelvic floor ultrasound: a review. Am J Obstet Gynecol 2010; 202: 321 334. 9. Svabík K, Martan A, Masata J, El-Haddad R, Hubka P, Pavlikova M. Ultrasound appearances after mesh implantation evidence of mesh contraction or folding? Int Urogynecol J 2011; 22: 529 533. 10. Dietz HP, Erdmann M, Shek KL. Mesh contraction: myth or reality? Am J Obstet Gynecol 2011; 204: 173.e1 4. 11. Barber MD, Walters MD, Bump RC. Short forms of two condition-specific quality-of-life questionnaires for women with pelvic floor disorders (PFDI-20 and PFIQ-7). Am J Obstet Gynecol 2005; 193: 103 113. 12. Bump RC, Mattiasson A, Bø K, Brubaker LP, DeLancey JO, Klarskov P, Shull BL, Smith AR. The standardization of terminology of female pelvic organ prolapse and pelvic floor dysfunction. Am J Obstet Gynecol 1996; 175: 10 17. 13. Dietz HP, Haylen BT, Broome J. Ultrasound in the quantification of female pelvic organ prolapse. Ultrasound Obstet Gynecol 2001; 18: 511 514. 14. Feiner B, Maher C. Vaginal mesh contraction: definition, clinical presentation, and management. Obstet Gynecol 2010; 115: 325 330. 15. Dietz HP. Mesh in prolapse surgery: an imaging perspective. Ultrasound Obstet Gynecol 2012; 40: 495 503. 16. Svabik K, Martan A, Masata J, Elhaddad R. Vaginal mesh shrinking ultrasound assessment and quantification. Int Urogynecol J 2009; 20: S166. 17. Model AN, Shek KL, Dietz HP. Levator defects are associated with prolapse after pelvic floor surgery. Eur J Obstet Gynecol Reprod Biol 2010; 153: 220 223. 18. Wong V, Shek K, Rane A, Goh J, Krause H, Dietz HP. Is levator avulsion a predictor of cystocele recurrence following anterior vaginal mesh placement? Ultrasound Obstet Gynecol 2013;42: 230 234.