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Monofilament and multifilament tape usage in incontinence surgery
Letters to the Editors
www. AJOG.org
Monofilament and multifilament tape usage in incontinence surgery TO THE EDITORS: In the article published by Meschia et al,1 the authors reported a randomized control trial of 2 commercial kits used to perform the same operation, a tension-free midurethral sling. I was interested to know the technique the group used for mesh tape placement in both the monofilament tension-fee vaginal tape (TVT) (Gynecare) and multifilament intravaginal slingplasty (IVS) (Tyco) slings. The multifilament mesh is nonstretch. Therefore, it should be set to actually touch the urethra. The reason that a space is left between the monofilament mesh and urethra is that this mesh is elastic and contracts after insertion. Rechberger et al2 found no erosion in either sling in a randomized trial, equivalent cure rates, but a statistically greater incidence of postoperative urinary retention in the monofilament. Lim et al3 in a 3-way trial among Sparc (monofilament), TVT (monofilament), and IVS (multifilament) also found equivalent cure rates but tape rejection rates of 13.7%, 3.5%, and 1.7%, respectively. The authors concluded that the differences in tape rejection were most likely due to technique. It is important to understand that the generic name for this operation is intravaginal slingplasty. The anatomical restoration is identical, the placement of a woven polypropylene tape without tension at midurethra. TVT (Gynecare) and IVS (Tyco) are registered trade names. So the differences in results need to be explained by differences in the tape qualities or the surgical technique used. A “hanging” loop of multifilament tape as applied in the report1 is more likely to cause mechanical irritation of the fresh wound to stimulate various lytic enzymes released from macrophages and other inflammatory cells to degrade the connective tissue, eventually resulting in protrusion of the tape. In contrast, an elastic tape will contract toward the urethra, potentially causing more postoperative urinary retention.2 This elasticity and greater diameter thread (100 to 150 m) may be the prime reason for the significant number of urethral erosions reported at the Maude (Food and Drug Administration) Web site, a Web site for voluntary reporting of adverse events (http://www.accessdata.fda.gov/
scripts/cdrh/cfdocs/cfMAUDE/search.cfm). Furthermore, the wide spaces between the fibrils and thick fibrils (100 to 150 m) create a thick collagen reaction around the fibrils, which may make removal difficult. The smaller diameter of the fibrils (20 to 30 m) and far larger number results in a much smaller force per unit area exerted on the urethra. This may explain why no urethral erosions have been reported to date on the Maude Web site for the IVS tape. However, the greater density of the multifilament creates more collagen in total. The closely woven nature of the tape creates a cylinder, which surrounds the tape, making it easier to remove. Each tape is different and has its own peculiar risks and benefits. How each is used is critical for the results obtained, an issue discussed by Lim et al.1 Given the results of previous randomized, controlled trials,2,3 leaving a gap between the urethra and multifilament tapes causes perhaps a greater incidence of erosion and an inf ferior cure rate. Peter Petros, MD, PhD, DS, FRCOG, FRANZCOG Royal Perth Hospital Department of Gynaecology 14A Osborne Pde Claremont, Western Australia 6010 Australia REFERENCES 1. Meschia M, Pifarotti P, Bernasconi F, Magatti F, Vigano R, Bertozzi R, et al. Tension-free vaginal tape (TVT) and intravaginal slingplasty (IVS) for stress urinary incontinence: a multicenter randomized trial. Am J Obstet Gynecol 2006;195:1338-42. 2. Rechberger T, Rzezniczuk K, Skorupski P, Adamiak A, Tomaszewski J, Baranowski W, et al. A randomized comparison between monofilament and multifilament tapes for stress incontinence surgery. Int Urogynecol J Pelvic Floor Dysfunct 2003;14:432-6. 3. Lim YN, Muller R, Corstiaans A, Dietz HP, Barry C, Rane A. Suburethral slingplasty evaluation study in North Queensland, Australia: the SUSPEND trial. Aust N Z J Obstet Gynaecol 2005;45:52-9. © 2007 Mosby, Inc. All rights reserved. doi: 10.1016/j.ajog.2006.08.014
REPLY We thank Professor Petros for the comments on our study. As stated in the article, the technique used for tape insertion was similar for both procedures, and we always performed a cough stress test for tensioning the sling; therefore, the position of the tape under the urethra was related to the results of the tension test as suggested by Professor Ulmsten in his original work.1 Probably the elastic properties of the multifilament tape might explain some of the differences reported such as time for resumption of spontaneous voiding or the incidence of postoperative urinary retention. We believe that the greater incidence of tape protrusion observed in the intravaginal slingplasty (IVS) group is related to e12
American Journal of Obstetrics & Gynecology FEBRUARY 2007
the multifilament threads of the sling according to similar experiences reported recently by different authors (references 1618). Lim et al2 reported a protrusion incidence of the IVS tape of 1.7%, but we must emphasize that the follow-up was limited to 6-12 weeks; therefore, the true incidence of protrusion could be greater with longer follow-up. In our study we had 8 patients (9%) with sling protrusion that never resolved with medical treatment, and 3 of them had a late presentation of purulent collection in the retropubic space; moreover, similar figures were observed in our recent study, presented at the International Urogynecological Association meeting in 2005, in which the IVS tape was used for vaginal cuff suspension.
www. AJOG.org
Monofilament and multifilament tape usage in incontinence surgery TO THE EDITORS: In the article published by Meschia et al,1 the authors reported a randomized control trial of 2 commercial kits used to perform the same operation, a tension-free midurethral sling. I was interested to know the technique the group used for mesh tape placement in both the monofilament tension-fee vaginal tape (TVT) (Gynecare) and multifilament intravaginal slingplasty (IVS) (Tyco) slings. The multifilament mesh is nonstretch. Therefore, it should be set to actually touch the urethra. The reason that a space is left between the monofilament mesh and urethra is that this mesh is elastic and contracts after insertion. Rechberger et al2 found no erosion in either sling in a randomized trial, equivalent cure rates, but a statistically greater incidence of postoperative urinary retention in the monofilament. Lim et al3 in a 3-way trial among Sparc (monofilament), TVT (monofilament), and IVS (multifilament) also found equivalent cure rates but tape rejection rates of 13.7%, 3.5%, and 1.7%, respectively. The authors concluded that the differences in tape rejection were most likely due to technique. It is important to understand that the generic name for this operation is intravaginal slingplasty. The anatomical restoration is identical, the placement of a woven polypropylene tape without tension at midurethra. TVT (Gynecare) and IVS (Tyco) are registered trade names. So the differences in results need to be explained by differences in the tape qualities or the surgical technique used. A “hanging” loop of multifilament tape as applied in the report1 is more likely to cause mechanical irritation of the fresh wound to stimulate various lytic enzymes released from macrophages and other inflammatory cells to degrade the connective tissue, eventually resulting in protrusion of the tape. In contrast, an elastic tape will contract toward the urethra, potentially causing more postoperative urinary retention.2 This elasticity and greater diameter thread (100 to 150 m) may be the prime reason for the significant number of urethral erosions reported at the Maude (Food and Drug Administration) Web site, a Web site for voluntary reporting of adverse events (http://www.accessdata.fda.gov/
scripts/cdrh/cfdocs/cfMAUDE/search.cfm). Furthermore, the wide spaces between the fibrils and thick fibrils (100 to 150 m) create a thick collagen reaction around the fibrils, which may make removal difficult. The smaller diameter of the fibrils (20 to 30 m) and far larger number results in a much smaller force per unit area exerted on the urethra. This may explain why no urethral erosions have been reported to date on the Maude Web site for the IVS tape. However, the greater density of the multifilament creates more collagen in total. The closely woven nature of the tape creates a cylinder, which surrounds the tape, making it easier to remove. Each tape is different and has its own peculiar risks and benefits. How each is used is critical for the results obtained, an issue discussed by Lim et al.1 Given the results of previous randomized, controlled trials,2,3 leaving a gap between the urethra and multifilament tapes causes perhaps a greater incidence of erosion and an inf ferior cure rate. Peter Petros, MD, PhD, DS, FRCOG, FRANZCOG Royal Perth Hospital Department of Gynaecology 14A Osborne Pde Claremont, Western Australia 6010 Australia REFERENCES 1. Meschia M, Pifarotti P, Bernasconi F, Magatti F, Vigano R, Bertozzi R, et al. Tension-free vaginal tape (TVT) and intravaginal slingplasty (IVS) for stress urinary incontinence: a multicenter randomized trial. Am J Obstet Gynecol 2006;195:1338-42. 2. Rechberger T, Rzezniczuk K, Skorupski P, Adamiak A, Tomaszewski J, Baranowski W, et al. A randomized comparison between monofilament and multifilament tapes for stress incontinence surgery. Int Urogynecol J Pelvic Floor Dysfunct 2003;14:432-6. 3. Lim YN, Muller R, Corstiaans A, Dietz HP, Barry C, Rane A. Suburethral slingplasty evaluation study in North Queensland, Australia: the SUSPEND trial. Aust N Z J Obstet Gynaecol 2005;45:52-9. © 2007 Mosby, Inc. All rights reserved. doi: 10.1016/j.ajog.2006.08.014
REPLY We thank Professor Petros for the comments on our study. As stated in the article, the technique used for tape insertion was similar for both procedures, and we always performed a cough stress test for tensioning the sling; therefore, the position of the tape under the urethra was related to the results of the tension test as suggested by Professor Ulmsten in his original work.1 Probably the elastic properties of the multifilament tape might explain some of the differences reported such as time for resumption of spontaneous voiding or the incidence of postoperative urinary retention. We believe that the greater incidence of tape protrusion observed in the intravaginal slingplasty (IVS) group is related to e12
American Journal of Obstetrics & Gynecology FEBRUARY 2007
the multifilament threads of the sling according to similar experiences reported recently by different authors (references 1618). Lim et al2 reported a protrusion incidence of the IVS tape of 1.7%, but we must emphasize that the follow-up was limited to 6-12 weeks; therefore, the true incidence of protrusion could be greater with longer follow-up. In our study we had 8 patients (9%) with sling protrusion that never resolved with medical treatment, and 3 of them had a late presentation of purulent collection in the retropubic space; moreover, similar figures were observed in our recent study, presented at the International Urogynecological Association meeting in 2005, in which the IVS tape was used for vaginal cuff suspension.