- Email: [email protected]
A New Quadratic Sling for Male Stress Incontinence: Retrograde Leak Point Pressure as a Measure of Urethral Resistance
A New Quadratic Sling for Male Stress Incontinence: Retrograde Leak Point Pressure as a Measure of Urethral Resistance Craig V. Comiter,*,† Victor Nitti,‡ Christopher Elliot§ and Eugene Rhee储 From Stanford University School of Medicine, Stanford (CVC, CE), and Kaiser Permanente, San Diego (ER), California, and New York University School of Medicine, New York, New York (VN)
Purpose: Objective methods are essential for evaluating post-prostatectomy incontinence. While symptom score and pad weight may be the most useful methods to evaluate preoperative vs postoperative continence, neither is useful for guiding intraoperative sling tension. The Virtue quadratic sling (Coloplast, Humlebaek, Denmark) is a new device for treating post-prostatectomy incontinence that combines a transobturator and prepubic surgical approach. We examined urethral resistance by measuring retrograde leak point pressure during key portions of the surgery. Materials and Methods: A total of 22 consecutive men who elected to undergo Virtue sling surgery were evaluated with retrograde leak point pressure before and during the surgery. Retrograde leak point pressure was measured via perfusion sphincterometry at baseline, after transobturator tensioning, after prepubic tensioning, and after transobturator and prepubic arms were secured in place. Results: Mean patient age was 70 years. Mean baseline retrograde leak point pressure was 33.4 ⫾ 8.8 cm water. After transobturator tensioning, mean retrograde leak point pressure increased to 43.3 ⫾ 6.8 cm water. After prepubic tensioning mean retrograde leak point pressure was 55.8 ⫾ 8.7, and final retrograde leak point pressure after transobturator and prepubic fixation increased to 68.8 ⫾ 6.0 cm water. Each mean retrograde leak point pressure value was significantly higher than the preceding value. Conclusions: The Virtue sling provides ventral urethral elevation using a transobturator approach, and a long segment of urethral compression against the genitourinary diaphragm via a straightforward prepubic technique without the risks of bone screws or retropubic needle passage. Transobturator and prepubic components of the quadratic fixation contributed to increasing urethral resistance as measured by intraoperative retrograde leak point pressure. This quadratic technique has a potentially greater ability to provide urethral compression than does a purely perineal or transobturator sling. Key Words: urinary incontinence, stress; suburethral slings; urologic surgical procedures, male OBJECTIVE methods of assessing SUI are essential for properly evaluating post-prostatectomy incontinence and for measuring the response to therapy. While symptom score and pad weight may be the most useful methods of evaluating preoperative vs
postoperative SUI, neither can be used for intraoperative guidance regarding proper sling tension. The measurement of retrograde leak point pressure has been validated as a reproducible and accurate method of measuring urethral resis-
0022-5347/12/1872-0563/0 THE JOURNAL OF UROLOGY® © 2012 by AMERICAN UROLOGICAL ASSOCIATION EDUCATION
Vol. 187, 563-568, February 2012 Printed in U.S.A. DOI:10.1016/j.juro.2011.09.152
AND
RESEARCH, INC.
Abbreviations and Acronyms ALPP ⫽ abdominal leak point pressure AUS ⫽ artificial urinary sphincter MUCP ⫽ maximal urethral closure pressure PP ⫽ prepubic PPI ⫽ post-prostatectomy incontinence RLPP ⫽ retrograde leak point pressure SUI ⫽ stress urinary incontinence TO ⫽ transobturator Submitted for publication May 3, 2011. Study received local institutional review board approval. * Correspondence: 300 Pasteur Drive, Room S-287, Stanford, California 94305-5118 (telephone: 650-723-3391; FAX: 650-724-9608; e-mail: [email protected]). † Financial interest and/or other relationship with Coloplast and Curant. ‡ Financial interest and/or other relationship with Allergan, American Medical Systems, Astellas, Coloplast, Ethicon, Medtronic, Pfizer, Serenity and Uroplasty. § Nothing to disclose. 储 Financial interest and/or other relationship with Coloplast and American Medical Systems.
Editor’s Note: This article is the fourth of 5 published in this issue for which category 1 CME credits can be earned. Instructions for obtaining credits are given with the questions on pages 770 and 771.
www.jurology.com
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tance in men with PPI due to intrinsic sphincter deficiency.1,2 In men with intrinsic sphincter deficiency RLPP correlates closely with ALPP and MUCP, but can be measured via perfusion sphincterometry without complex urodynamic equipment.3 Additionally, measuring RLPP is a valuable method of evaluating the integrity of the artificial urinary sphincter and guiding proper tensioning during sling placement.4 – 6 The Virtue quadratic sling is a new device for treating PPI consisting of a large pore knitted monofilament polypropylene mesh with 2 pre-attached inferior (transobturator) extensions and 2 superior (prepubic) extensions. As the surgical use of this and other slings has become increasingly popular, it is important to evaluate the efficacy of these novel devices in an objective and standardized manner. While several tools are currently used to evaluate and compare sling efficacy such as the Patient Global Impression of Improvement,7 pad weight and incontinence questionnaires, methods to standardize the surgical technique are generally lacking. However, only with a standardized technique can results be adequately compared. Unlike tension-free slings in women with SUI, male slings are placed under tension to achieve appropriate urethral elevation and/or compression, and this tension must be maintained postoperatively.8 We describe a standardized procedure for placement of the Virtue quadratic sling based on the experience of implanting urologists during a multicenter clinical evaluation of this new device. We evaluate the resistance of the sling to leakage via measurement of RLPP during key intraoperative steps. Standardization of the surgical technique should facilitate comparative and objective evaluation of the efficacy and safety of this new procedure.
MATERIALS AND METHODS As part of the evaluation of a new surgical technique for PPI, 22 consecutive men who elected to undergo Virtue sling surgery were evaluated with RLPP at the start of surgery, and at critical stages of sling tensioning and fixation during surgery. At each site local institutional review board approval was obtained. Patients were appropriate surgical candidates if they had post-prostatectomy SUI and normal bladder contractility on urodynamics. Bladder contractility was considered normal if there was a sustained increase in detrusor pressure during pressure flow study or during the continuous occlusion test.9 Patients with detrusor areflexia and/or post-void residual urine volume greater than 150 cc were excluded from analysis. Patients with a history of postoperative radiation were excluded only if treated with radiotherapy within the previous 6 months.
Sling Placement After the administration of general or spinal anesthesia and intravenous antibiotics, the patient was placed in the dorsal lithotomy position, and sterilely prepared and draped. A 14Fr urethral catheter was inserted. The ventral bulbous urethra and pubic rami were exposed through a 5 cm vertical perineal incision, leaving the bulbospongiosus muscle intact. The urethra was detached from the perineal body to allow proximal urethral repositioning upon sling tensioning. TO passage. On each side the inferior sling arm (TO extensions) was attached to the curved introducer, which was passed from medial to lateral (at the level of the bulbar urethra) through the obturator foramen via an inside-out maneuver. Through a small groin stab wound the sling was then removed from the introducer, and pulled through the tissue from medial to lateral. PP passage. A stab incision was made 2 cm above the pubic symphysis and 3 cm lateral to the midline on either side. The curved introducer was passed from above, through the pubic incision, anterior to the pubic bone, and out through the perineal incision lateral to the urethra on each side. The superior sling arm was attached to the proximal slot of the introducer and pulled up through the incision on each side.
RLPP Measurement RLPP was measured via perfusion sphincterometry. With a 14Fr Foley catheter in the penile urethra the balloon is filled with 1 cc water. A 1 l bag of saline is connected to the catheter via cystoscopy tubing with the drip chamber half full. RLPP is measured as the height of the water column (cm water) at which sling resistance is overcome and fluid flow commences (fig. 1).3 Baseline RLPP was measured before sling passage. RLPP measurement was then repeated after tensioning of the TO extensions sufficient to move the bulbar urethra 3 cm proximally.10 The sling was then loosened and RLPP was measured after tensioning of the PP component, with the surgeon applying sufficient upward tension to provide visual compression of the sling against the genitourinary diaphragm. Final RLPP was measured after re-tensioning and fixation of the TO and PP sling components, with a goal of 60 to 70 cm water (fig. 2).
Sling Fixation After cutting the ends of the TO arms the plastic sleeve was removed. On each side a long clamp was then passed from the perineal incision to the ipsilateral groin stab wound, and the sling arm was grasped and pulled back through to the perineal incision. While tension was maintained the arms were secured in the midline with a 1-zero polypropylene suture. With the assistant pulling up on the PP arms (with enough tension to provide visual compression of the sling against the genitourinary diaphragm) the plastic sleeves were removed, and a 1-zero polypropylene suture was placed through the inferior aspect of each PP arm, securing it to the soft tissue overlying the bone 1 cm lateral to the urethra at the inferior aspect of the symphysis pubis. The perineal incision and stab wounds were closed. The urethral catheter was maintained overnight and removed
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operative complications and all patients were able to achieve a final RLPP greater than 60 cm water. Final RLPP measurement was an average of 106% greater than baseline.
DISCUSSION
Figure 1. RLPP measurement. 14Fr catheter in penile urethra is connected to cystoscopy tubing and 1 l bag of water. RLPP is equal to height of fluid column at which flow through tubing (and, therefore, urethral sphincter) commences.
While reported rates of PPI vary depending on the definition of incontinence, length of followup and method of evaluation, approximately 6% to 9% of patients will have enough bother from urinary leakage after prostate cancer surgery to seek further treatment.11,12 There are currently no Food and Drug Administration approved pharmacotherapeutic treatments for male SUI and periurethral bulking agents are typically inefficacious beyond the short term.13 AUS placement has been considered the gold standard treatment for PPI in the last 30 years, demonstrating a high rate of success regardless of the degree of leakage. However, a 5-year revision rate greater than 20%, a reported infection rate of 6% and an erosion rate of 5% to 8% in contemporary large cohort series,14,15 as well as patients’ desire to avoid a mechanical device, have fostered the search for alternative options. In the last decade various slings have emerged as popular alternatives to the AUS. The modern sling evolved from the abdominal perineal sling of Schaeffer et al,16 to the bone anchored perineal sling6 (InVance™), the transobturator sling17 (AdVance™) and the recently introduced Virtue quadratic sling. The principles of successful sling surgery in men with PPI are similar regardless of the particular device used, in that 1) appropriate sling tension is
the following morning at home. Patients were instructed to refrain from strenuous activity for 8 weeks. Oral antibiotics were given for 5 days.
RESULTS Mean patient age in the cohort was 70 years (range 56 to 84). Mean baseline RLPP was 33.4 ⫾ 8.8 cm water. After TO passage and tensioning and re-tunneling of the inferior extensions, mean RLPP increased to 43.3 ⫾ 6.8 cm water (p ⬍0.01 vs baseline). After the tension was released on the TO extensions, and after PP passage, tensioning and fixation of the superior sling extensions, mean RLPP increased to 55.8 ⫾ 8.7 cm water (p ⬍0.01 vs baseline). Final RLPP after tensioning and fixation of the TO and the PP arms increased to 68.8 ⫾ 6.0 cm water (p ⬍0.01 vs baseline, p ⬍0.01 vs TO tension and p ⬍0.01 vs PP tension, fig. 3). There were no intra-
Figure 2. Sling fixation. Transobturator extensions are tunneled back medially to perineal incision and secured to each other in midline with 1-zero polypropylene suture. Prepubic arms are secured to periosteum of pubic symphysis using 1-zero polypropylene suture.
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75 60 RLPP (cm water)
45 30 15 0 Baseline
TO
PP
Final
Figure 3. Urethral resistance during key intraoperative steps. Progressive increase in urethral resistance with transobturator sling tensioning and with prepubic sling tensioning.
needed for the restoration of continence, 2) overcorrection can result in urinary retention, 3) undercorrection can result in persistent incontinence and 4) bladder emptying is optimized when implants do not significantly obstruct urinary flow. Whereas pubourethral and transobturator slings for women with SUI are typically placed with minimal tension, the male sling must be placed under sufficient tension to compress the bulbous urethra and/or sufficiently relocate the proximal urethra. In addition, tension must be maintained to prevent recurrent sphincteric insufficiency. Active urethral compression is invariably lost with autolysis of absorbable materials.8 The Virtue quadratic sling is composed of permanent synthetic (polypropylene) material, and recent modifications in technique have incorporated a method of intraoperative fixation of the TO and the PP extensions, which appears to be a more reliable method of maintaining urethral compression than mere friction and postoperative tissue ingrowth. While the surgeon can observe compression of the sling against the urethra, measure proximal relocation of the bulbar urethra, and even cystoscopically observe luminal coaptation, neither closure pressure nor urethral resistance may be visually quantified with a high degree of accuracy. Rather, adequate urethral compression is best assessed via a functional measure of urethral resistance to flow. RLPP measurement is an accepted and validated test of urethral sphincteric competence in men with PPI related to intrinsic sphincter deficiency.1–3 RLPP is measured via perfusion sphincterometry, and has been shown to be a useful quantification of urethral resistance during male anti-incontinence surgery.4–6 In men with PPI who are devoid of a properly functioning proximal sphincter and bladder neck, the intrinsic component of the distal sphincter is responsible for most of the patients’ urinary continence.18 Additionally, RLPP has been shown to correlate well
with other accepted measures of urethral sphincteric function, including ALPP and MUCP.3 ALPP is difficult to measure during surgery in the anesthetized patient and furthermore is best measured via rectal manometry,19 which is a cumbersome technique to perform during sterile perineal surgery. MUCP is best measured via urethral pressure profilometry and typically relies on complex urodynamic equipment. In contrast, RLPP can be measured simply with a catheter, cystoscopy tubing and a bag of water without the need for patient cooperation. Furthermore, intraoperative RLPP is highly correlated with postoperative RLPP in male sling cases.20 The 2 most popular sling devices used to treat post-prostatectomy SUI are the AdVance TO sling and the InVance bone anchored perineal sling. It is hypothesized that the mechanism of action of the TO sling involves supporting the dorsal distal aspect of the male urethral sphincter mechanism. With the sling placed behind the lumen of the membranous urethra, it is theorized that sphincter support laxity can be corrected, augmenting the residual (albeit weak) sphincter function by lengthening the function zone of coaptation.10,17 The mechanism of action of the bone anchored sling is more obvious, with direct compression of the urethra against the genitourinary diaphragm. By combining the efficacious mechanisms of action of each of these sling surgeries, the Virtue quadratic sling has the potential to increase urethral resistance to a greater degree than either a purely TO or purely perineal approach. This hypothesis is supported by the demonstration of an additive increase in RLPP after the tensioning of the TO extensions and after tensioning of the PP extensions. At the end of surgery RLPP was consistently higher than after tensioning either component alone in this cohort of men with PPI. The PP component not only provides a long segment of urethral compression but also prevents the proximal migration of the TO component of the sling. With a purely TO approach excessive sling tension with inadequate fixation of the sling to the urethra may result in accidental migration of the sling in a dorsocranial position, opening up the membranous urethra rather than supporting it from behind, thereby potentially worsening incontinence.17 In addition, the quadratic sling compresses the urethra against the genitourinary diaphragm without the need for bone anchors, reducing the risk of bony complications that may be associated with titanium screws. Finally, prepubic sling passage avoids the scarred retropubic space, eliminating the risk of retropubic bladder injury. We experienced no instances of bladder injury, whereas in 2 recent cohort studies of an adjustable pubourethral male sling (Argus, Promedon SA, Cordoba, Argentina, and Remeex,
SPHINCTEROMETRY PREDICTS MALE SLING MECHANISM OF ACTION
Neomedic, Barcelona, Spain), the retropubic needle passage was associated with an intraoperative urethral or bladder injury rate of 6% to 10%.21,22 RLPP is not a measure of sling efficacy. Rather pad use, pad weight and quality of life are better determinants of surgical outcome. However, RLPP is a useful measure of the degree of intraoperative urethral compression and a potentially important method of standardizing the intraoperative tension applied to the male sling. It is important to note that with TO tensioning there is a maximal bulbar urethral relocation of approximately 3 cm regardless of further sling tightening. However, RLPP continues to increase with increased PP sling tension. In this procedure the PP extensions are ultimately tensioned to achieve a RLPP of 61 to 70 cm water, and are tightened or loosened appropriately to achieve that degree of urethral resistance. The goal of 61 to 70 cm water is based on the decades of success with the AUS device, the majority of which are implanted with a 61 to 70 cm water pressure balloon.23 Only rarely is a lower pressure balloon (radiation)24 or higher pressure balloon (revision for urethral atrophy)25 recommended. Based on experience with the bone anchored sling it is clear that suboptimal tensioning is associated with surgical failure. A low RLPP (less than 50 cm water) was associated with increased incontinence compared to patients who achieved RLPP greater than 60 cm.20 On the other hand, excess sling tension appears to be a risk factor for urinary retention. In a cohort of
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48 men in whom a RLPP of 60 to 70 cm water was achieved, none experienced urinary retention.26 However, there are known instances of urinary retention when sling tension is not appropriately monitored. Standardization of sling tension will not only guide proper surgical technique, but will also permit valid comparisons among incontinence devices with potentially different mechanisms of action.
CONCLUSIONS The Virtue sling achieves bulbous urethral proximal relocation using a TO technique combined with urethral compression against the perineal membrane via a straightforward PP approach. The quadratic design allows for a long segment of urethral compression while avoiding the risks associated with bone screws and retropubic trocar passage. The TO and PP components contribute to increasing urethral resistance as measured by progressive increases in intraoperative RLPP. By combining the efficacious mechanisms of action of a TO and a perineal sling, the quadratic fixation technique appears to have a potentially greater ability to provide urethral compression. The precise determination of sling tension via RLPP measurement is an important component of standardizing the technique of male sling surgery. Quantification of intraoperative sling tension not only guides proper surgical technique, but also facilitates comparison among different cohorts of patients undergoing various sling surgeries.
REFERENCES 1. Comiter CV, Sullivan MP and Yalla SV: Retrograde leak point pressure for evaluating post-radical prostatectomy incontinence. Urology 1997; 49: 231. 2. Bamshad BR, Hadley HR, Ruckle HC et al: Perfusion sphincterometry for objective evaluation of postprostatectomy intrinsic sphincter deficiency. Urology 1997; 53: 968. 3. Comiter CV, Sullivan MP and Yalla SV: Correlation among maximal urethral closure pressure, retrograde leak point pressure, and abdominal leak point pressure in men with postprostatectomy stress incontinence. Urology 2003; 62: 75. 4. Choe JM, Battino BS and Bell TE: Retrograde perfusion sphincterometry with a flexible cystoscope: method of troubleshooting the AMS 800. Urology 2000; 56: 317. 5. Leach GE and Raz S: Perfusion sphincterometry: method of intraoperative evaluation of artificial urinary sphincter function. Urology 1983; 21: 312. 6. Giberti C, Gallo F, Schenone M et al: The boneanchor sub-urethral sling for the treatment of iatrogenic male incontinence: subjective and ob-
jective assessment after 41 months of mean follow-up. World J Urol 2008; 26: 173. 7. Fischer MC, Huckabay C and Nitti VW: The male perineal sling: assessment and prediction of outcome. J Urol 2007; 177: 1414. 8. Rajpurkar AD, Onur R and Singla A: Patient satisfaction and clinical efficacy of the new perineal bone-anchored male sling. Eur Urol 2005; 47: 237. 9. Sullivan MP, DuBeau CE, Resnick NM et al: Continuous occlusion test to determine detrusor contractile performance. J Urol 1995; 154: 1834. 10. Rapp DE, Reynolds WS, Lucioni A et al: Surgical technique using AdVance sling placement in the treatment of post-prostatectomy urinary incontinence. Int Braz J Urol 2007; 33: 231. 11. Stanford JL, Feng Z, Hamilton AS et al: Urinary and sexual function after radical prostatectomy for clinically localized prostate cancer: the Prostate Cancer Outcome Study. JAMA 2000; 283: 354.
12. Kundu SD, Roehl KA, Eggener SE et al: Potency, continence and complications in 3,477 consecutive radical retropubic prostatectomies. J Urol 2004; 172: 2227. 13. Herschorn S, Bruschini H, Comiter CV et al: Surgical treatment of stress incontinence in men. Neurourol Urodyn 2010; 29: 179. 14. Kim SP, Sarmast Z, Daignault S et al: Long-term durability and functional outcomes among patients with the artificial urinary sphincters: a 10-year retrospective review from the University of Michigan. J Urol 2008; 179: 1912. 15. Lai HH, Hsu EI, Teh BS et al: 13 years of experience with artificial urinary sphincter implantation at Baylor College of Medicine. J Urol 2007; 177: 1021. 16. Schaeffer AJ, Clemens JQ, Ferrari M et al: The male bulbourethral sling procedure for post-radical prostatectomy incontinence. J Urol 1998; 159: 1510. 17. Rehder P, von Gleissenthall GF, Pichler R et al: The treatment of postprostatectomy incontinence with the retroluminal transobturator re-
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positioning sling (AdVance): lessons learnt from accumulative experience. Arch Esp Urol 2009; 62: 860.
with questionnaire based assessment. J Urol 2004; 172: 207.
nary sphincter: analysis of 144 patients. J Urol 1993; 150: 1412.
18. Groutz A, Blaivas JG, Chaikin DC et al: The pathophysiology of post-radical prostatectomy incontinence: a clinical and video urodynamic study. J Urol 2000; 163: 1767.
21. Romano SV, Metrebian SE, Vaz F et al: Long-term results of a phase II multicenter trial of the adjustable male sling for treating urinary incontinence after prostatectomy: minimum 3 years. Actas Urol Esp 2009; 33: 309.
24. Wang Y and Hadley HR: Experiences with the artificial urinary sphincter in the irradiated patient. J Urol 1992; 147: 612.
19. Flood HD, Alevizatos C and Liu JL: Sex differences in the determination of abdominal leak point pressure in patients with intrinsic sphincter deficiency. J Urol 1996; 156: 1737.
22. Sousa-Escandon A, Cabrera J, Mantovani F et al: Adjustable suburethral sling (male remeex system) in the treatment of male stress urinary incontinence: a multicentric European study. Eur Urol 2007; 52: 1473.
20. Ullrich NF and Comiter CV: The male sling for stress urinary incontinence: 24-month followup
23. Leo ME and Barrett DM: Success of the narrowbacked cuff design of the AMS800 artificial uri-
25. DiMarco DS and Elliott DS: Tandem cuff artificial urinary sphincter as a salvage procedure following failed primary sphincter placement for the treatment of post-prostatectomy incontinence. J Urol 2003; 170: 1252. 26. Comiter CV: The male perineal sling: intermediate-term results. Neurourol Urodyn 2005; 24: 648.
Purpose: Objective methods are essential for evaluating post-prostatectomy incontinence. While symptom score and pad weight may be the most useful methods to evaluate preoperative vs postoperative continence, neither is useful for guiding intraoperative sling tension. The Virtue quadratic sling (Coloplast, Humlebaek, Denmark) is a new device for treating post-prostatectomy incontinence that combines a transobturator and prepubic surgical approach. We examined urethral resistance by measuring retrograde leak point pressure during key portions of the surgery. Materials and Methods: A total of 22 consecutive men who elected to undergo Virtue sling surgery were evaluated with retrograde leak point pressure before and during the surgery. Retrograde leak point pressure was measured via perfusion sphincterometry at baseline, after transobturator tensioning, after prepubic tensioning, and after transobturator and prepubic arms were secured in place. Results: Mean patient age was 70 years. Mean baseline retrograde leak point pressure was 33.4 ⫾ 8.8 cm water. After transobturator tensioning, mean retrograde leak point pressure increased to 43.3 ⫾ 6.8 cm water. After prepubic tensioning mean retrograde leak point pressure was 55.8 ⫾ 8.7, and final retrograde leak point pressure after transobturator and prepubic fixation increased to 68.8 ⫾ 6.0 cm water. Each mean retrograde leak point pressure value was significantly higher than the preceding value. Conclusions: The Virtue sling provides ventral urethral elevation using a transobturator approach, and a long segment of urethral compression against the genitourinary diaphragm via a straightforward prepubic technique without the risks of bone screws or retropubic needle passage. Transobturator and prepubic components of the quadratic fixation contributed to increasing urethral resistance as measured by intraoperative retrograde leak point pressure. This quadratic technique has a potentially greater ability to provide urethral compression than does a purely perineal or transobturator sling. Key Words: urinary incontinence, stress; suburethral slings; urologic surgical procedures, male OBJECTIVE methods of assessing SUI are essential for properly evaluating post-prostatectomy incontinence and for measuring the response to therapy. While symptom score and pad weight may be the most useful methods of evaluating preoperative vs
postoperative SUI, neither can be used for intraoperative guidance regarding proper sling tension. The measurement of retrograde leak point pressure has been validated as a reproducible and accurate method of measuring urethral resis-
0022-5347/12/1872-0563/0 THE JOURNAL OF UROLOGY® © 2012 by AMERICAN UROLOGICAL ASSOCIATION EDUCATION
Vol. 187, 563-568, February 2012 Printed in U.S.A. DOI:10.1016/j.juro.2011.09.152
AND
RESEARCH, INC.
Abbreviations and Acronyms ALPP ⫽ abdominal leak point pressure AUS ⫽ artificial urinary sphincter MUCP ⫽ maximal urethral closure pressure PP ⫽ prepubic PPI ⫽ post-prostatectomy incontinence RLPP ⫽ retrograde leak point pressure SUI ⫽ stress urinary incontinence TO ⫽ transobturator Submitted for publication May 3, 2011. Study received local institutional review board approval. * Correspondence: 300 Pasteur Drive, Room S-287, Stanford, California 94305-5118 (telephone: 650-723-3391; FAX: 650-724-9608; e-mail: [email protected]). † Financial interest and/or other relationship with Coloplast and Curant. ‡ Financial interest and/or other relationship with Allergan, American Medical Systems, Astellas, Coloplast, Ethicon, Medtronic, Pfizer, Serenity and Uroplasty. § Nothing to disclose. 储 Financial interest and/or other relationship with Coloplast and American Medical Systems.
Editor’s Note: This article is the fourth of 5 published in this issue for which category 1 CME credits can be earned. Instructions for obtaining credits are given with the questions on pages 770 and 771.
www.jurology.com
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tance in men with PPI due to intrinsic sphincter deficiency.1,2 In men with intrinsic sphincter deficiency RLPP correlates closely with ALPP and MUCP, but can be measured via perfusion sphincterometry without complex urodynamic equipment.3 Additionally, measuring RLPP is a valuable method of evaluating the integrity of the artificial urinary sphincter and guiding proper tensioning during sling placement.4 – 6 The Virtue quadratic sling is a new device for treating PPI consisting of a large pore knitted monofilament polypropylene mesh with 2 pre-attached inferior (transobturator) extensions and 2 superior (prepubic) extensions. As the surgical use of this and other slings has become increasingly popular, it is important to evaluate the efficacy of these novel devices in an objective and standardized manner. While several tools are currently used to evaluate and compare sling efficacy such as the Patient Global Impression of Improvement,7 pad weight and incontinence questionnaires, methods to standardize the surgical technique are generally lacking. However, only with a standardized technique can results be adequately compared. Unlike tension-free slings in women with SUI, male slings are placed under tension to achieve appropriate urethral elevation and/or compression, and this tension must be maintained postoperatively.8 We describe a standardized procedure for placement of the Virtue quadratic sling based on the experience of implanting urologists during a multicenter clinical evaluation of this new device. We evaluate the resistance of the sling to leakage via measurement of RLPP during key intraoperative steps. Standardization of the surgical technique should facilitate comparative and objective evaluation of the efficacy and safety of this new procedure.
MATERIALS AND METHODS As part of the evaluation of a new surgical technique for PPI, 22 consecutive men who elected to undergo Virtue sling surgery were evaluated with RLPP at the start of surgery, and at critical stages of sling tensioning and fixation during surgery. At each site local institutional review board approval was obtained. Patients were appropriate surgical candidates if they had post-prostatectomy SUI and normal bladder contractility on urodynamics. Bladder contractility was considered normal if there was a sustained increase in detrusor pressure during pressure flow study or during the continuous occlusion test.9 Patients with detrusor areflexia and/or post-void residual urine volume greater than 150 cc were excluded from analysis. Patients with a history of postoperative radiation were excluded only if treated with radiotherapy within the previous 6 months.
Sling Placement After the administration of general or spinal anesthesia and intravenous antibiotics, the patient was placed in the dorsal lithotomy position, and sterilely prepared and draped. A 14Fr urethral catheter was inserted. The ventral bulbous urethra and pubic rami were exposed through a 5 cm vertical perineal incision, leaving the bulbospongiosus muscle intact. The urethra was detached from the perineal body to allow proximal urethral repositioning upon sling tensioning. TO passage. On each side the inferior sling arm (TO extensions) was attached to the curved introducer, which was passed from medial to lateral (at the level of the bulbar urethra) through the obturator foramen via an inside-out maneuver. Through a small groin stab wound the sling was then removed from the introducer, and pulled through the tissue from medial to lateral. PP passage. A stab incision was made 2 cm above the pubic symphysis and 3 cm lateral to the midline on either side. The curved introducer was passed from above, through the pubic incision, anterior to the pubic bone, and out through the perineal incision lateral to the urethra on each side. The superior sling arm was attached to the proximal slot of the introducer and pulled up through the incision on each side.
RLPP Measurement RLPP was measured via perfusion sphincterometry. With a 14Fr Foley catheter in the penile urethra the balloon is filled with 1 cc water. A 1 l bag of saline is connected to the catheter via cystoscopy tubing with the drip chamber half full. RLPP is measured as the height of the water column (cm water) at which sling resistance is overcome and fluid flow commences (fig. 1).3 Baseline RLPP was measured before sling passage. RLPP measurement was then repeated after tensioning of the TO extensions sufficient to move the bulbar urethra 3 cm proximally.10 The sling was then loosened and RLPP was measured after tensioning of the PP component, with the surgeon applying sufficient upward tension to provide visual compression of the sling against the genitourinary diaphragm. Final RLPP was measured after re-tensioning and fixation of the TO and PP sling components, with a goal of 60 to 70 cm water (fig. 2).
Sling Fixation After cutting the ends of the TO arms the plastic sleeve was removed. On each side a long clamp was then passed from the perineal incision to the ipsilateral groin stab wound, and the sling arm was grasped and pulled back through to the perineal incision. While tension was maintained the arms were secured in the midline with a 1-zero polypropylene suture. With the assistant pulling up on the PP arms (with enough tension to provide visual compression of the sling against the genitourinary diaphragm) the plastic sleeves were removed, and a 1-zero polypropylene suture was placed through the inferior aspect of each PP arm, securing it to the soft tissue overlying the bone 1 cm lateral to the urethra at the inferior aspect of the symphysis pubis. The perineal incision and stab wounds were closed. The urethral catheter was maintained overnight and removed
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operative complications and all patients were able to achieve a final RLPP greater than 60 cm water. Final RLPP measurement was an average of 106% greater than baseline.
DISCUSSION
Figure 1. RLPP measurement. 14Fr catheter in penile urethra is connected to cystoscopy tubing and 1 l bag of water. RLPP is equal to height of fluid column at which flow through tubing (and, therefore, urethral sphincter) commences.
While reported rates of PPI vary depending on the definition of incontinence, length of followup and method of evaluation, approximately 6% to 9% of patients will have enough bother from urinary leakage after prostate cancer surgery to seek further treatment.11,12 There are currently no Food and Drug Administration approved pharmacotherapeutic treatments for male SUI and periurethral bulking agents are typically inefficacious beyond the short term.13 AUS placement has been considered the gold standard treatment for PPI in the last 30 years, demonstrating a high rate of success regardless of the degree of leakage. However, a 5-year revision rate greater than 20%, a reported infection rate of 6% and an erosion rate of 5% to 8% in contemporary large cohort series,14,15 as well as patients’ desire to avoid a mechanical device, have fostered the search for alternative options. In the last decade various slings have emerged as popular alternatives to the AUS. The modern sling evolved from the abdominal perineal sling of Schaeffer et al,16 to the bone anchored perineal sling6 (InVance™), the transobturator sling17 (AdVance™) and the recently introduced Virtue quadratic sling. The principles of successful sling surgery in men with PPI are similar regardless of the particular device used, in that 1) appropriate sling tension is
the following morning at home. Patients were instructed to refrain from strenuous activity for 8 weeks. Oral antibiotics were given for 5 days.
RESULTS Mean patient age in the cohort was 70 years (range 56 to 84). Mean baseline RLPP was 33.4 ⫾ 8.8 cm water. After TO passage and tensioning and re-tunneling of the inferior extensions, mean RLPP increased to 43.3 ⫾ 6.8 cm water (p ⬍0.01 vs baseline). After the tension was released on the TO extensions, and after PP passage, tensioning and fixation of the superior sling extensions, mean RLPP increased to 55.8 ⫾ 8.7 cm water (p ⬍0.01 vs baseline). Final RLPP after tensioning and fixation of the TO and the PP arms increased to 68.8 ⫾ 6.0 cm water (p ⬍0.01 vs baseline, p ⬍0.01 vs TO tension and p ⬍0.01 vs PP tension, fig. 3). There were no intra-
Figure 2. Sling fixation. Transobturator extensions are tunneled back medially to perineal incision and secured to each other in midline with 1-zero polypropylene suture. Prepubic arms are secured to periosteum of pubic symphysis using 1-zero polypropylene suture.
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SPHINCTEROMETRY PREDICTS MALE SLING MECHANISM OF ACTION
75 60 RLPP (cm water)
45 30 15 0 Baseline
TO
PP
Final
Figure 3. Urethral resistance during key intraoperative steps. Progressive increase in urethral resistance with transobturator sling tensioning and with prepubic sling tensioning.
needed for the restoration of continence, 2) overcorrection can result in urinary retention, 3) undercorrection can result in persistent incontinence and 4) bladder emptying is optimized when implants do not significantly obstruct urinary flow. Whereas pubourethral and transobturator slings for women with SUI are typically placed with minimal tension, the male sling must be placed under sufficient tension to compress the bulbous urethra and/or sufficiently relocate the proximal urethra. In addition, tension must be maintained to prevent recurrent sphincteric insufficiency. Active urethral compression is invariably lost with autolysis of absorbable materials.8 The Virtue quadratic sling is composed of permanent synthetic (polypropylene) material, and recent modifications in technique have incorporated a method of intraoperative fixation of the TO and the PP extensions, which appears to be a more reliable method of maintaining urethral compression than mere friction and postoperative tissue ingrowth. While the surgeon can observe compression of the sling against the urethra, measure proximal relocation of the bulbar urethra, and even cystoscopically observe luminal coaptation, neither closure pressure nor urethral resistance may be visually quantified with a high degree of accuracy. Rather, adequate urethral compression is best assessed via a functional measure of urethral resistance to flow. RLPP measurement is an accepted and validated test of urethral sphincteric competence in men with PPI related to intrinsic sphincter deficiency.1–3 RLPP is measured via perfusion sphincterometry, and has been shown to be a useful quantification of urethral resistance during male anti-incontinence surgery.4–6 In men with PPI who are devoid of a properly functioning proximal sphincter and bladder neck, the intrinsic component of the distal sphincter is responsible for most of the patients’ urinary continence.18 Additionally, RLPP has been shown to correlate well
with other accepted measures of urethral sphincteric function, including ALPP and MUCP.3 ALPP is difficult to measure during surgery in the anesthetized patient and furthermore is best measured via rectal manometry,19 which is a cumbersome technique to perform during sterile perineal surgery. MUCP is best measured via urethral pressure profilometry and typically relies on complex urodynamic equipment. In contrast, RLPP can be measured simply with a catheter, cystoscopy tubing and a bag of water without the need for patient cooperation. Furthermore, intraoperative RLPP is highly correlated with postoperative RLPP in male sling cases.20 The 2 most popular sling devices used to treat post-prostatectomy SUI are the AdVance TO sling and the InVance bone anchored perineal sling. It is hypothesized that the mechanism of action of the TO sling involves supporting the dorsal distal aspect of the male urethral sphincter mechanism. With the sling placed behind the lumen of the membranous urethra, it is theorized that sphincter support laxity can be corrected, augmenting the residual (albeit weak) sphincter function by lengthening the function zone of coaptation.10,17 The mechanism of action of the bone anchored sling is more obvious, with direct compression of the urethra against the genitourinary diaphragm. By combining the efficacious mechanisms of action of each of these sling surgeries, the Virtue quadratic sling has the potential to increase urethral resistance to a greater degree than either a purely TO or purely perineal approach. This hypothesis is supported by the demonstration of an additive increase in RLPP after the tensioning of the TO extensions and after tensioning of the PP extensions. At the end of surgery RLPP was consistently higher than after tensioning either component alone in this cohort of men with PPI. The PP component not only provides a long segment of urethral compression but also prevents the proximal migration of the TO component of the sling. With a purely TO approach excessive sling tension with inadequate fixation of the sling to the urethra may result in accidental migration of the sling in a dorsocranial position, opening up the membranous urethra rather than supporting it from behind, thereby potentially worsening incontinence.17 In addition, the quadratic sling compresses the urethra against the genitourinary diaphragm without the need for bone anchors, reducing the risk of bony complications that may be associated with titanium screws. Finally, prepubic sling passage avoids the scarred retropubic space, eliminating the risk of retropubic bladder injury. We experienced no instances of bladder injury, whereas in 2 recent cohort studies of an adjustable pubourethral male sling (Argus, Promedon SA, Cordoba, Argentina, and Remeex,
SPHINCTEROMETRY PREDICTS MALE SLING MECHANISM OF ACTION
Neomedic, Barcelona, Spain), the retropubic needle passage was associated with an intraoperative urethral or bladder injury rate of 6% to 10%.21,22 RLPP is not a measure of sling efficacy. Rather pad use, pad weight and quality of life are better determinants of surgical outcome. However, RLPP is a useful measure of the degree of intraoperative urethral compression and a potentially important method of standardizing the intraoperative tension applied to the male sling. It is important to note that with TO tensioning there is a maximal bulbar urethral relocation of approximately 3 cm regardless of further sling tightening. However, RLPP continues to increase with increased PP sling tension. In this procedure the PP extensions are ultimately tensioned to achieve a RLPP of 61 to 70 cm water, and are tightened or loosened appropriately to achieve that degree of urethral resistance. The goal of 61 to 70 cm water is based on the decades of success with the AUS device, the majority of which are implanted with a 61 to 70 cm water pressure balloon.23 Only rarely is a lower pressure balloon (radiation)24 or higher pressure balloon (revision for urethral atrophy)25 recommended. Based on experience with the bone anchored sling it is clear that suboptimal tensioning is associated with surgical failure. A low RLPP (less than 50 cm water) was associated with increased incontinence compared to patients who achieved RLPP greater than 60 cm.20 On the other hand, excess sling tension appears to be a risk factor for urinary retention. In a cohort of
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48 men in whom a RLPP of 60 to 70 cm water was achieved, none experienced urinary retention.26 However, there are known instances of urinary retention when sling tension is not appropriately monitored. Standardization of sling tension will not only guide proper surgical technique, but will also permit valid comparisons among incontinence devices with potentially different mechanisms of action.
CONCLUSIONS The Virtue sling achieves bulbous urethral proximal relocation using a TO technique combined with urethral compression against the perineal membrane via a straightforward PP approach. The quadratic design allows for a long segment of urethral compression while avoiding the risks associated with bone screws and retropubic trocar passage. The TO and PP components contribute to increasing urethral resistance as measured by progressive increases in intraoperative RLPP. By combining the efficacious mechanisms of action of a TO and a perineal sling, the quadratic fixation technique appears to have a potentially greater ability to provide urethral compression. The precise determination of sling tension via RLPP measurement is an important component of standardizing the technique of male sling surgery. Quantification of intraoperative sling tension not only guides proper surgical technique, but also facilitates comparison among different cohorts of patients undergoing various sling surgeries.
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