Neurourology and Urodynamics 34:679–684 (2015)
Comparative Analysis of the Pressure Profilometry of Vesicocutaneous Continent Catheterizable Conduits Between Patients With and Without Rectus Abdominis Neosphincter (Yachia Principle) Atila Rondon,* Bruno Leslie, Leonardo Javier Arcuri, Valdemar Ortiz and Antonio Macedo Jr Department of Urology, Universidade Federal de Sa~o Paulo, Sa~o Paulo, Brazil
Aims: To assess whether crossing rectus abdominis muscle strips, as proposed by Yachia, would change urinary catheterizable conduit’s pressure profilometry, in static and dynamic conditions. Methods: Non-randomized selection of 20 continent patients that underwent Macedo’s ileum-based reservoir, 10 including Yachia’s technique (Study Group) and 10 without this mechanism of continence (Control Group). Demographics and cystometric data were assessed. Conduit’s pressure profilometry was obtained by infusing saline through a multichannel catheter, at rest and during Valsalva maneuver. We assessed the pressure: (a) in the bladder; (b) in conduit’s proximal segment; and (c) in conduit’s distal segment, which is presumably the abdominal wall and crossed muscle strips site. Results: Mean age at surgery was 6.1 years in the Control Group and 7.7 years in the Study Group. There was no statistically significant difference between groups regarding maximum cystometric bladder capacity and leakage point pressure. At rest, the pressure profilometry showed similar results between groups in all segments analyzed. During Valsalva maneuver, pressure profilometry showed similar results between groups in bladder and conduit’s proximal segment pressure. In this condition, conduit’s distal segment pressure in the Study Group (Mean ¼ 72.9 and Peak ¼ 128.7 cmH2O) was significantly greater (P < 0.05) than conduit’s distal segment pressure in the Control Group (Mean ¼ 48.3 and Peak ¼ 65.1 cmH2O). Conclusions: Crossing muscle strips over the conduit significantly increases the pressure in its distal segment during contraction of the rectus abdominis muscle, which can be important in moments of sudden increase in abdominal pressure in order to keep continence. Neurourol. Urodynam. 34:679–684, 2015. # 2014 Wiley Periodicals, Inc. Key words: rectus abdominis; urinary catheterization; urinary diversion; urinary incontinence; urodynamics
INTRODUCTION
Clean intermittent catheterization (CIC) introduced by Lapides (1972)1 and the Mitrofanoff procedure (1980)2 revolutionized the management of urinary incontinence. Many structures have been proposed in an attempt to create continent conduits similar to the appendix following the Mitrofanoff principle.3–11 Regardless of the type of conduit used, failure due to incontinence is reported in around 10% of cases in the literature.12–15 Principles of continence of catheterizable urinary conduits are based on the attempt to maintain the conduit’s luminal pressure above the reservoir pressure.16 Three principles have gained clinical relevance over time: flap, nipple, and hydraulic valves.17 But after 30 years of development of techniques for continent cutaneous diversion there is no consensus on the best method to be used. Yachia proposed a different mechanism based on crossing two strips of rectus abdominis muscle over a catheterizable conduit as a way to enhance resistance and reduce leakage rates in catheterizable reservoirs18,19 (Fig. 1). Damazio et al.20 tested this procedure in rabbits and reported no deleterious compression of the muscle over a conduit made with two skin flaps. In an attempt to reduce the 13% of incontinence rate observed in Macedo’s ileum-based reservoir,21 the author joined Yachia’s technique and Macedo’s technique and published a series of 16 primary reconstructions and 6 rescue cases for leaking stomas. Overall continence was 100% for primary cases and 66% for redos.22 #
2014 Wiley Periodicals, Inc.
Nevertheless, it is unclear whether the crossed muscle strips simulates a muscle sphincter mechanism, increasing the pressure in the conduit with rectus abdominis contraction or if it promotes a passive increase in resistance by the interposition of another tissue in the same path. Herein, we investigated whether crossing rectus abdominis muscle strips, as proposed by Yachia, would change urinary catheterizable conduit’s pressure profilometry, in static and dynamic conditions, leading to improved continence. MATERIALS AND METHODS Subjects
After approval by the Ethics in Research Committee of our institution, we selected 20 continent patients with at least 1 year of post-operative follow-up, 10 patients including Yachia’s technique (Study Group) and 10 patients without this mechanism of continence (Control Group). Urinary continence was defined as a dry interval of >4 hr, confirmed by a Roger Dmochowski led the peer-review process as the Associate Editor responsible for the paper. Conflict of interest: none. *Correspondence to: Atila Rondon, Rua Maestro Cardim, 560/215, 01323-000 S~ ao Paulo, Brazil. E-mail: [email protected] Received 19 March 2014; Accepted 14 May 2014 Published online 29 June 2014 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/nau.22643
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Fig. 1. Yachia’s procedure performed in midline. (A) Two rectus abdominis strips of 1.5 cm; (B) checking muscle mobility and; (C) conduit in between the crossing muscles (adapted from Macedo et al.22).
3-day bladder diary. All patients were regularly performing CIC through the conduit at the time of the urodynamic studies. At our institution from 1998 to 2009 bladder reconstructions were performed using Macedo’s Ileum-based reservoir and this population was the source of Control Group. Yachia’s procedure has been performed in all patients since 2009 and this younger population was the source of Study Group. We selected the first 10 consecutive patients that presented to the outpatient clinic for regular follow-up visits with the characteristics needed to be included in each group. Cystometrogram
Urodynamic studies were performed with patients in supine position. Firstly, it was slowly introduced the usual catheter used for CIC (mostly a 12-F catheter) in the stoma until urine started to drain from the bladder. The distance between the lateral orifice at the tip of the catheter and the point of the catheter at the level of the skin at this moment was called estimated conduit’s length. Bladder was then emptied. Secondly, the urethra was catheterized with a 7-F doublelumen urodynamic catheter and the bladder was filled with saline with a roller infusion pump at a rate determined by the cystometric capacity estimated by the 3-day bladder diary as shown in the formula: Fill rate (cc per minute) ¼ mean volume per catheterization/10. In patients without urethral access to the bladder, filling was performed through the conduit. No rectal catheter was used to monitor intra-abdominal pressure. Intravesical pressure was recorded by a multichannel uro~o Paulo, Brazil). dynamic processor (Dynamed Corp., Sa Maximum cystometric bladder capacity (MCC) was determined according to the moment when occurred: (a) raise in bladder pressure over 40 cmH2O23; (b) urinary leakage through conduit or urethra; and (c) pain. Conduit’s leak point pressure (LPP) was defined as the pressure in the bladder at which the first drops of urine passed through the conduit and were noted by the examiner.
tip. With patients in supine position, at rest, the catheter was introduced in the conduit until the radial orifices had passed 1 cm beyond the estimated conduit’s length and then was manually withdrawn at a rate of 15 mm per second while pressures were recorded by a multichannel manometry processor (Dynamed Corp.). Intravesical pressure was monitored during pressure profilometry study by the doublelumen transurethral catheter. Figure 2 shows a scheme representing the multichannel catheter inserted into the conduit and the double-lumen catheter inserted through the urethra. The first four polygraph channels record the radial pressure of the conduit and the fifth channel records the bladder pressure. Dynamic Conduit’s Pressure Profilometry
The same steps were followed still in supine position but this time with patients performing the Valsalva’s maneuver with the maximum effort they were able to sustain for about 5 sec. Patients were asked to forcibly blow against the back of their hand while making a closed fist without any air leakage. Intravesical pressure was monitored and when it achieved a plateau during Valsalva’s maneuver the multichannel catheter was then withdrawn. Pressure Profilometry Curves Analysis
Pressures were assessed: (a) in the bladder; (b) in conduit’s proximal segment; and (c) in conduit’s distal segment, which is presumably the abdominal wall and crossed muscle strips site. Limits of each segment were identified according to the estimated conduit’s length and the numbered marks of centimeters along the multichannel catheter body (Fig. 2). Two measures were used for the comparative analysis between groups: (a) mean pressure, calculated as the mean of all pressures recorded within the range of a segment; and (b) peak pressure, calculated as the mean of the maximum pressure observed in a segment.
Static Conduit’s Pressure Profilometry
After bladder filling to the MCC, 10% of the infused saline was aspirated before performing pressure profilometry study, in an attempt to simulate the moment when patients usually perform catheterization before any leakage occurs. Conduit’s pressure profilometry was obtained by infusing saline at a rate of 0.56 ml per minute through a multichannel PVC catheter of 2.5 mm in diameter with four radial ports at the Neurourology and Urodynamics DOI 10.1002/nau
Statistical Methods
Statistical analysis was performed using ‘‘R’’ statistical software (Vienna, Austria, version 3.0.2-2013) with P < 0.05 considered significant. Demographics were summarized as follows: ‘‘age’’ using means plus or minus standard deviations and differences assessed using Student’s t test; ‘‘follow-up’’ using median and interquartile range and differences assessed
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Fig. 2. Scheme representing the multichannel catheter inserted into the conduit and the double-lumen catheter inserted through the urethra. The first fourpolygraph channels record the radial pressure of the conduit and the fifth channel records the bladder pressure. Limits of each studied segment are shown in static condition (A) and in dynamic condition (B). B, bladder; CP, conduit proximal segment; CD, conduit distal segment.
using Wilcoxon rank sum test; ‘‘Gender’’ and ‘‘diagnosis’’ were grouped into categorical variables and differences were assessed using Fisher exact test. Correlation between variables was assessed using Pearson or Spearman correlation coefficients when appropriate. Concerning the pressure profilometry, differences were assessed using Student’s t test if results presented a normal distribution or Wilcoxon rank sum test if a non-parametric test was indicated. Kruskal–Wallis nonparametric test was used to compare more than two independent samples. RESULTS Demographics
Control and Study groups had a similar mean age at surgery, 6.1 and 7.7 years, respectively (P ¼ 0.14). However, Control Group presented mean current age of 15 years, while in the Study Group it was 10.5 years, a statistically significant difference (P ¼ 0.006). This is explained by the fact that Yachia’s procedure has been performed in all patients since 2009 and this younger population was the source of Study Group. Control Group consequently presented a significantly higher follow-up, median of 9.5 years, while in Study Group it was 3 years (P < 0.001). Most of them were Spina Bifida patients (80%), two patients had bladder exstrophy, one had rhabdomyosarcoma and one an anorectal malformation. Cystometrogram
There was no difference in the estimated conduit’s length between groups, with 6.3 cm in the Control Group and 6.8 cm in the Study Group (P ¼ 0.57). The mean MCC was 452.6 ml in the Control Group and 341.7 ml in the Study Group (P ¼ 0.10). In four patients of Control Group, catheterization with doublelumen catheter for bladder filling was performed through the Neurourology and Urodynamics DOI 10.1002/nau
conduit because no urethral access was available. In the Study Group, three patients presented leakage through the urethra and one patient complained of pain before any leakage occurred. Therefore, conduit’s LPP was assessed in six patients in the Control Group and six patients in the Study Group. Mean conduit’s LPP was 16.3 cmH2O in the Control Group and 22.7 cmH2O in the Study Group (P ¼ 0.12). Cystometrogram data are summarized in Table I. Conduit’s Pressure Profilometry
Pressure values in each segment studied showed no correlation with any of the variables (e.g., age, gender, diagnosis, MCC, and LPP). Table II presents the mean or median pressure of each segment, comparing the results between Control Group and Study Group, with the P value. The use of mean or median was determined by the statistical analysis used. Static Conduit’s Pressure Profilometry
At rest, there was no statistically significant difference in bladder and conduit’s proximal and distal segments pressure between Control and Study groups, with both mean and peak pressure analyzed. Low bladder pressures with 90% of MCC
TABLE I. Summary of Cystometrogram Results
MCC (ml) Mean (SD) Conduit length (cm) Mean (SD) LPP (cmH2O) Mean (SD)
Study
Control
P
341.7 (107.7)
452.6 (168.3)
0.10
6.8 (1.5)
6.3 (2.3)
0.57
22.7 (8.0)
16.3 (4.4)
0.12
MCC, maximum cystometric bladder capacity; SD, standard deviation.
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TABLE II. Mean and Peak Pressure of Each Segment in Static and Dynamic Conditions Study Static (cmH2O) Bladder Mean 1.4 Peak 3.6 Proximal conduit Mean 7.6 Peak 12.5 Distal conduit Mean 27.1 Peak 48.6 Dynamic (cmH2O) Bladder Mean 21.0 Peak 27.7 Proximal conduit Mean 22.8 Peak 30.0 Distal conduit Mean 72.9 Peak 128.7 Increase in conduit’s distal pressure Mean 45.8 Peak 86.3
Control
P
1.2 3.7
0.73 0.94
6.1 12.2
0.71 0.79
31.4 51.0
0.61 1.00
24.0 29.5
0.42 0.69
21.1 25.0
1.00 0.68
48.3 65.1
0.0499 0.0126
16.9 20.0
0.003 0.022
Median.
filled were observed in both groups. In Study Group, at rest, mean and peak bladder pressure were 1.4 and 3.6 cmH2O, respectively, while in Control Group the results were 1.2 and 3.7 cmH2O (P ¼ 0.73 and P ¼ 0.94), respectively. In all cases, pressure in the conduit’s proximal segment was higher than the bladder pressure in both groups. In Study Group, at rest, mean and peak conduit’s proximal segment pressure were 7.6 and 12.5 cmH2O, respectively, while in the Control Group the results were 6.1 and 12.2 cmH2O (P ¼ 0.71 and P ¼ 0.79), respectively. Conduit’s distal segment pressure was in all cases higher than the conduit’s proximal segment pressure in both groups. In Study Group, at rest, mean and peak conduit’s distal pressure were 27.1 and 48.6 cmH2O, respectively, while in the Control Group the results were 31.4 and 51.0 cmH2O (P ¼ 0.61 and P ¼ 1.00), respectively. Dynamic Conduit’s Pressure Profilometry
During Valsalva maneuver, there was no statistically significant difference in bladder or conduit’s proximal segment pressure between groups. In Study Group, bladder mean and peak pressure were 21.0 and 27.7 cmH2O, respectively, while in Control Group the results were 24.0 and 29.5 cmH2O (P ¼ 0.42 and P ¼ 0.69), respectively. In Study Group, mean and peak pressure in conduit’s proximal segment were 22.8 and 30.0 cmH2O, respectively, while in Control Group the results were 21.1 and 25.0 cmH2O (P ¼ 1.00 and P ¼ 0.68), respectively. In the other hand, there was a statistically significant difference in conduit’s distal segment pressure between Control and Study groups with both mean and peak pressure analyzed. In Study Group, during Valsalva maneuver, the mean and peak pressure in the conduit’s distal segment were 72.9 and 128.7 cmH2O, respectively, while in Control Group the results were 48.3 and 65.1 cmH2O (P ¼ 0.0499 and P ¼ 0.0126), respectively. Boxplots of the difference found in conduit’s distal segment are shown in Figure 3(A and B). Neurourology and Urodynamics DOI 10.1002/nau
Difference Between Static and Dynamic Conduit’s Distal Pressure
The difference between values of static and dynamic conduit’s distal pressure represents how much elevation occurred in distal pressure with Valsalva maneuver. This increase in distal pressure was significantly higher in the Study Group when compared to Control Group (P ¼ 0.003) as shown in Table II. This difference was statistically significant when both mean and peak pressure were analyzed as shown in Figure 3(C and D).
DISCUSSION
The history of the development of bladder diversion demonstrates the intense search for the best combination of reservoir, conduit, and continence mechanism in an attempt to obtain good capacity, easy access through catheterization and quality of life, essential items to ensure the success of the procedure. The numerous options available in the literature and the number of articles being published uninterruptedly with new surgical approaches show that an ideal, universal, and reproducible procedure has not yet been found.17 Yachia published two articles using the crossed rectus abdominis strips as the only mechanism of continence and reported 100% of continence rate in both.18,19 According to the author, he found an increased pressure at the muscle level, especially during abdominal contraction. However, none of the papers presented the data or the techniques how the pressure profile was obtained. Hinman,16 in his study on the functional classification of the conduits, cites a possible contribution of the abdominal wall in continence, by constriction of the conduit, even without performing any local procedure. Only one controlled study would determine the real contribution to the pressure exerted on the conduit caused by the crossed muscle strips. Conduit’s LPP in the Study Group was higher than in Control Group, 22.7 and 16.3 cmH2O, respectively, but this difference was not statistically significant. There was no correlation between LPP and pressures found in the conduit at rest. Due to the unavailable urethral access or urethral urine leakage in some patients, samples were reduced and the analysis of this parameter was impaired. An increase in pressure, even at rest, at the level of the abdominal wall musculature from 10–25 to 45–60 cmH2O, when patients pass from supine to the upright position has been reported.19,24 Such behavior would be expected due to the muscle tonus needed to keep the patient upright and could represent a component in preserving continence. Possibly the Yachia’s mechanism could cause a greater increase in pressure. However, due to significant motor deficit of the lower limbs, which greatly hindered patient’s postural control, we were unable to perform the exam in this position. Control Group presented mean current age of 15 years, while in the Study Group it was 10.5 years, a statistically significant difference (P ¼ 0.006). That was one of our concerns but our feeling was that older patients would have more strength and possibly would be able to perform more efficient Valsalva maneuver. But that was not observed in the pressures measured inside the bladder. Both groups achieved similar bladder pressures and in fact the younger group presented higher distal efferent segment pressures under Valsalva. We had two populations with an age difference between them. We designed a study with the highest level of evidence possible using the available population and to our knowledge this is the only evidence available to date. Watson et al.25 published a study comparing appendix, ureter, ileum, and stomach conduit’s pressure in children. They
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Fig. 3. (A and B) Boxplots of the difference found in conduit’s distal segment during Valsalva’s maneuver between Study and Control groups. A, difference in distal mean pressure; and B, difference in distal peak pressure. (C and D) Boxplots of the difference found in the increase in conduit’s distal segment during Valsalva’s maneuver between Study and Control groups. C, difference in the increase in distal mean pressure and; D, difference in the increase in distal peak pressure.
found that the functional profile length, defined as the length of the conduit over, which conduit pressure remained greater than reservoir pressure, was correlated to continence when greater than 2 cm. The authors associated this measure to the intramural tunnel but did not mention the abdominal wall as an area of increased pressure. Our results demonstrated that the abdominal wall was capable of exerting a pressure of 25– 30 cmH2O above the bladder pressure, regardless of the presence of the intersection of the muscle strips. The pressure in the proximal portion of the conduit, presumably the site of the serous tunnel was also higher than the bladder pressure, with a difference of 5–6 (mean) and 9 (peak) cmH2O. Thus, the location of higher pressure and therefore with greater contribution to continence at rest was the abdominal wall in both groups. The distal portion of the conduit is presumably the abdominal wall and the crossed muscle strips site. During Valsalva maneuver, pressure at this site was significantly higher in the Study Group. We also compared the increase in conduit’s distal pressure in both groups. Some patients had a Neurourology and Urodynamics DOI 10.1002/nau
high distal pressure at rest, possibly justified by areas of narrowing of the canal. In Valsalva, these pressures remained elevated but not because of a muscular component. When we assessed the increase in conduit’s distal pressure, from static to dynamic condition, we naturally evaluated the increment of pressure obtained by muscular contraction. In the Control Group, the increase in conduit’s distal pressure was proportional to the increase in bladder pressure, while in the Study Group the rise in distal pressure was greater than the increase in bladder pressure. We can attribute this increase to the only factor that differentiates the two groups: the crossed rectus abdominis strips. CONCLUSIONS
Our study supports the use of Yachia’s technique as a continence mechanism enhancing the pressure inside the urinary conduit and therefore representing an extra barrier against urinary leakage. Crossing muscle strips over the conduit
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significantly increases the pressure in its distal segment during contraction of the rectus abdominis muscle. This mechanism may be especially important in order to keep continence during moments of sudden increase in abdominal pressure such as movement, coughing and sneezing, when abdominal muscles contract reflexively. REFERENCES 1. Lapides J, Diokno AC, Silber SJ, et al. Clean, intermittent self-catheterization in the treatment of urinary tract disease. J Urol 1972;107:458–61. 2. Mitrofanoff P. Trans-appendicular continent cystostomy in the management of the neurogenic bladder. Chir Pediatr 1980;21:297–305. 3. Monti PR, Lara RC, Dutra MA, et al. New techniques for construction of efferent conduits based on the Mitrofanoff principle. Urology 1997;49:112–5. 4. Sanda MG, Jeffs RD, Gearhart JP. Evolution of outcomes with the ileal hydraulic valve continent diversion: Reevaluation of the Benchekroun catheterizable stoma. World J Urol 1996;14:108–11. 5. Rowland RG. Present experience with the Indiana pouch. World J Urol 1996;14:92–8. 6. Xu YM, Qiao Y, Wu DL, et al. Efferent tube suspension as a continent diversion mechanism: A preliminary report of a clinical study. J Urol 2002;168:2027–9. 7. Tekant G, Emir H, Eroglu E, et al. Catheterisable continent urinary diversion (Mitrofanoff principle)—Clinical experience and psychological aspects. Eur J Pediatr Surg 2001;11:263–7. 8. Riedmiller H, Burger R, Muller S, et al. Continent appendix stoma: A modification of the Mainz pouch technique. J Urol 1990;143:1115–7. 9. Narayanaswamy B, Wilcox DT, Cuckow PM, et al. The Yang-Monti ileovesicostomy: A problematic channel? BJU Int 2001;87:861–5. 10. Mor Y, Kajbafzadeh AM, German K, et al. The role of ureter in the creation of Mitrofanoff channels in children. J Urol 1997;157:635–7. 11. Krstic ZD. Preputial continent vesicostomy: Preliminary report of a new technique. J Urol 1995;154:1160–1. 12. McAndrew HF, Malone PS. Continent catheterizable conduits: Which stoma, which conduit and which reservoir? BJU Int 2002;89:86–9.
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13. Piaggio L, Myers S, Figueroa TE, et al. Influence of type of conduit and site of implantation on the outcome of continent catheterizable channels. J Pediatr Urol 2007;3:230–4. 14. Barqawi A, de Valdenebro M, Furness PD 3rd, et al. Lessons learned from stomal complications in children with cutaneous catheterizable continent stomas. BJU Int 2004;94:1344–7. 15. Sahadevan K, Pickard RS, Neal DE, et al. Is continent diversion using the Mitrofanoff principle a viable long-term option for adults requiring bladder replacement? BJU Int 2008;102:236–40. 16. Hinman F Jr. Functional classification of conduits for continent diversion. J Urol 1990;144:27–30. 17. Ardelt PU, Woodhouse CR, Riedmiller H, et al. The efferent segment in continent cutaneous urinary diversion: A comprehensive review of the literature. BJU Int 2012;109:288–97. 18. Yachia D. A new continent vesicostomy technique: Preliminary report. J Urol 1997;157:1633–7. 19. Yachia D, Erlich N. The Hadera continent reservoir: A new appendicoumbilical continent stoma mechanism for urinary diversion. J Urol 2001; 165:1423–6. 20. Damazio E, Rondon A, Bacelar H, et al. Is it possible to use the rectus abdominis neo-sphincter as a continence mechanism for urinary catheterizable channels? A histologic and histochemical evaluation in an experimental study in rabbits. J Pediatr Urol 2013;9:919–26. 21. Macedo A Jr, Srougi M. A continent catheterizable ileum-based reservoir. BJU Int 2000;85:160–2. 22. Macedo A Jr, Damazio E, Bacelar H, et al. A neosphincter for continent urinary catheterizable channels made from rectus abdominal muscle (Yachia principle): Preliminary clinical experience in children. J Pediatr Urol 2013; 9:283–8. 23. McGuire EJ, Woodside JR, Borden TA. Upper urinary tract deterioration in patients with myelodysplasia and detrusor hypertonia: A followup study. J Urol 1983;129:823–6. 24. Koff SA. The abdominal neourethra in children: Technique and long-term results. J Urol 1985;133:244–7. 25. Watson HS, Bauer SB, Peters CA, et al. Comparative urodynamics of appendiceal and ureteral Mitrofanoff conduits in children. J Urol 1995; 154:878–82.
Comparative Analysis of the Pressure Profilometry of Vesicocutaneous Continent Catheterizable Conduits Between Patients With and Without Rectus Abdominis Neosphincter (Yachia Principle) Atila Rondon,* Bruno Leslie, Leonardo Javier Arcuri, Valdemar Ortiz and Antonio Macedo Jr Department of Urology, Universidade Federal de Sa~o Paulo, Sa~o Paulo, Brazil
Aims: To assess whether crossing rectus abdominis muscle strips, as proposed by Yachia, would change urinary catheterizable conduit’s pressure profilometry, in static and dynamic conditions. Methods: Non-randomized selection of 20 continent patients that underwent Macedo’s ileum-based reservoir, 10 including Yachia’s technique (Study Group) and 10 without this mechanism of continence (Control Group). Demographics and cystometric data were assessed. Conduit’s pressure profilometry was obtained by infusing saline through a multichannel catheter, at rest and during Valsalva maneuver. We assessed the pressure: (a) in the bladder; (b) in conduit’s proximal segment; and (c) in conduit’s distal segment, which is presumably the abdominal wall and crossed muscle strips site. Results: Mean age at surgery was 6.1 years in the Control Group and 7.7 years in the Study Group. There was no statistically significant difference between groups regarding maximum cystometric bladder capacity and leakage point pressure. At rest, the pressure profilometry showed similar results between groups in all segments analyzed. During Valsalva maneuver, pressure profilometry showed similar results between groups in bladder and conduit’s proximal segment pressure. In this condition, conduit’s distal segment pressure in the Study Group (Mean ¼ 72.9 and Peak ¼ 128.7 cmH2O) was significantly greater (P < 0.05) than conduit’s distal segment pressure in the Control Group (Mean ¼ 48.3 and Peak ¼ 65.1 cmH2O). Conclusions: Crossing muscle strips over the conduit significantly increases the pressure in its distal segment during contraction of the rectus abdominis muscle, which can be important in moments of sudden increase in abdominal pressure in order to keep continence. Neurourol. Urodynam. 34:679–684, 2015. # 2014 Wiley Periodicals, Inc. Key words: rectus abdominis; urinary catheterization; urinary diversion; urinary incontinence; urodynamics
INTRODUCTION
Clean intermittent catheterization (CIC) introduced by Lapides (1972)1 and the Mitrofanoff procedure (1980)2 revolutionized the management of urinary incontinence. Many structures have been proposed in an attempt to create continent conduits similar to the appendix following the Mitrofanoff principle.3–11 Regardless of the type of conduit used, failure due to incontinence is reported in around 10% of cases in the literature.12–15 Principles of continence of catheterizable urinary conduits are based on the attempt to maintain the conduit’s luminal pressure above the reservoir pressure.16 Three principles have gained clinical relevance over time: flap, nipple, and hydraulic valves.17 But after 30 years of development of techniques for continent cutaneous diversion there is no consensus on the best method to be used. Yachia proposed a different mechanism based on crossing two strips of rectus abdominis muscle over a catheterizable conduit as a way to enhance resistance and reduce leakage rates in catheterizable reservoirs18,19 (Fig. 1). Damazio et al.20 tested this procedure in rabbits and reported no deleterious compression of the muscle over a conduit made with two skin flaps. In an attempt to reduce the 13% of incontinence rate observed in Macedo’s ileum-based reservoir,21 the author joined Yachia’s technique and Macedo’s technique and published a series of 16 primary reconstructions and 6 rescue cases for leaking stomas. Overall continence was 100% for primary cases and 66% for redos.22 #
2014 Wiley Periodicals, Inc.
Nevertheless, it is unclear whether the crossed muscle strips simulates a muscle sphincter mechanism, increasing the pressure in the conduit with rectus abdominis contraction or if it promotes a passive increase in resistance by the interposition of another tissue in the same path. Herein, we investigated whether crossing rectus abdominis muscle strips, as proposed by Yachia, would change urinary catheterizable conduit’s pressure profilometry, in static and dynamic conditions, leading to improved continence. MATERIALS AND METHODS Subjects
After approval by the Ethics in Research Committee of our institution, we selected 20 continent patients with at least 1 year of post-operative follow-up, 10 patients including Yachia’s technique (Study Group) and 10 patients without this mechanism of continence (Control Group). Urinary continence was defined as a dry interval of >4 hr, confirmed by a Roger Dmochowski led the peer-review process as the Associate Editor responsible for the paper. Conflict of interest: none. *Correspondence to: Atila Rondon, Rua Maestro Cardim, 560/215, 01323-000 S~ ao Paulo, Brazil. E-mail: [email protected] Received 19 March 2014; Accepted 14 May 2014 Published online 29 June 2014 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/nau.22643
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Fig. 1. Yachia’s procedure performed in midline. (A) Two rectus abdominis strips of 1.5 cm; (B) checking muscle mobility and; (C) conduit in between the crossing muscles (adapted from Macedo et al.22).
3-day bladder diary. All patients were regularly performing CIC through the conduit at the time of the urodynamic studies. At our institution from 1998 to 2009 bladder reconstructions were performed using Macedo’s Ileum-based reservoir and this population was the source of Control Group. Yachia’s procedure has been performed in all patients since 2009 and this younger population was the source of Study Group. We selected the first 10 consecutive patients that presented to the outpatient clinic for regular follow-up visits with the characteristics needed to be included in each group. Cystometrogram
Urodynamic studies were performed with patients in supine position. Firstly, it was slowly introduced the usual catheter used for CIC (mostly a 12-F catheter) in the stoma until urine started to drain from the bladder. The distance between the lateral orifice at the tip of the catheter and the point of the catheter at the level of the skin at this moment was called estimated conduit’s length. Bladder was then emptied. Secondly, the urethra was catheterized with a 7-F doublelumen urodynamic catheter and the bladder was filled with saline with a roller infusion pump at a rate determined by the cystometric capacity estimated by the 3-day bladder diary as shown in the formula: Fill rate (cc per minute) ¼ mean volume per catheterization/10. In patients without urethral access to the bladder, filling was performed through the conduit. No rectal catheter was used to monitor intra-abdominal pressure. Intravesical pressure was recorded by a multichannel uro~o Paulo, Brazil). dynamic processor (Dynamed Corp., Sa Maximum cystometric bladder capacity (MCC) was determined according to the moment when occurred: (a) raise in bladder pressure over 40 cmH2O23; (b) urinary leakage through conduit or urethra; and (c) pain. Conduit’s leak point pressure (LPP) was defined as the pressure in the bladder at which the first drops of urine passed through the conduit and were noted by the examiner.
tip. With patients in supine position, at rest, the catheter was introduced in the conduit until the radial orifices had passed 1 cm beyond the estimated conduit’s length and then was manually withdrawn at a rate of 15 mm per second while pressures were recorded by a multichannel manometry processor (Dynamed Corp.). Intravesical pressure was monitored during pressure profilometry study by the doublelumen transurethral catheter. Figure 2 shows a scheme representing the multichannel catheter inserted into the conduit and the double-lumen catheter inserted through the urethra. The first four polygraph channels record the radial pressure of the conduit and the fifth channel records the bladder pressure. Dynamic Conduit’s Pressure Profilometry
The same steps were followed still in supine position but this time with patients performing the Valsalva’s maneuver with the maximum effort they were able to sustain for about 5 sec. Patients were asked to forcibly blow against the back of their hand while making a closed fist without any air leakage. Intravesical pressure was monitored and when it achieved a plateau during Valsalva’s maneuver the multichannel catheter was then withdrawn. Pressure Profilometry Curves Analysis
Pressures were assessed: (a) in the bladder; (b) in conduit’s proximal segment; and (c) in conduit’s distal segment, which is presumably the abdominal wall and crossed muscle strips site. Limits of each segment were identified according to the estimated conduit’s length and the numbered marks of centimeters along the multichannel catheter body (Fig. 2). Two measures were used for the comparative analysis between groups: (a) mean pressure, calculated as the mean of all pressures recorded within the range of a segment; and (b) peak pressure, calculated as the mean of the maximum pressure observed in a segment.
Static Conduit’s Pressure Profilometry
After bladder filling to the MCC, 10% of the infused saline was aspirated before performing pressure profilometry study, in an attempt to simulate the moment when patients usually perform catheterization before any leakage occurs. Conduit’s pressure profilometry was obtained by infusing saline at a rate of 0.56 ml per minute through a multichannel PVC catheter of 2.5 mm in diameter with four radial ports at the Neurourology and Urodynamics DOI 10.1002/nau
Statistical Methods
Statistical analysis was performed using ‘‘R’’ statistical software (Vienna, Austria, version 3.0.2-2013) with P < 0.05 considered significant. Demographics were summarized as follows: ‘‘age’’ using means plus or minus standard deviations and differences assessed using Student’s t test; ‘‘follow-up’’ using median and interquartile range and differences assessed
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Fig. 2. Scheme representing the multichannel catheter inserted into the conduit and the double-lumen catheter inserted through the urethra. The first fourpolygraph channels record the radial pressure of the conduit and the fifth channel records the bladder pressure. Limits of each studied segment are shown in static condition (A) and in dynamic condition (B). B, bladder; CP, conduit proximal segment; CD, conduit distal segment.
using Wilcoxon rank sum test; ‘‘Gender’’ and ‘‘diagnosis’’ were grouped into categorical variables and differences were assessed using Fisher exact test. Correlation between variables was assessed using Pearson or Spearman correlation coefficients when appropriate. Concerning the pressure profilometry, differences were assessed using Student’s t test if results presented a normal distribution or Wilcoxon rank sum test if a non-parametric test was indicated. Kruskal–Wallis nonparametric test was used to compare more than two independent samples. RESULTS Demographics
Control and Study groups had a similar mean age at surgery, 6.1 and 7.7 years, respectively (P ¼ 0.14). However, Control Group presented mean current age of 15 years, while in the Study Group it was 10.5 years, a statistically significant difference (P ¼ 0.006). This is explained by the fact that Yachia’s procedure has been performed in all patients since 2009 and this younger population was the source of Study Group. Control Group consequently presented a significantly higher follow-up, median of 9.5 years, while in Study Group it was 3 years (P < 0.001). Most of them were Spina Bifida patients (80%), two patients had bladder exstrophy, one had rhabdomyosarcoma and one an anorectal malformation. Cystometrogram
There was no difference in the estimated conduit’s length between groups, with 6.3 cm in the Control Group and 6.8 cm in the Study Group (P ¼ 0.57). The mean MCC was 452.6 ml in the Control Group and 341.7 ml in the Study Group (P ¼ 0.10). In four patients of Control Group, catheterization with doublelumen catheter for bladder filling was performed through the Neurourology and Urodynamics DOI 10.1002/nau
conduit because no urethral access was available. In the Study Group, three patients presented leakage through the urethra and one patient complained of pain before any leakage occurred. Therefore, conduit’s LPP was assessed in six patients in the Control Group and six patients in the Study Group. Mean conduit’s LPP was 16.3 cmH2O in the Control Group and 22.7 cmH2O in the Study Group (P ¼ 0.12). Cystometrogram data are summarized in Table I. Conduit’s Pressure Profilometry
Pressure values in each segment studied showed no correlation with any of the variables (e.g., age, gender, diagnosis, MCC, and LPP). Table II presents the mean or median pressure of each segment, comparing the results between Control Group and Study Group, with the P value. The use of mean or median was determined by the statistical analysis used. Static Conduit’s Pressure Profilometry
At rest, there was no statistically significant difference in bladder and conduit’s proximal and distal segments pressure between Control and Study groups, with both mean and peak pressure analyzed. Low bladder pressures with 90% of MCC
TABLE I. Summary of Cystometrogram Results
MCC (ml) Mean (SD) Conduit length (cm) Mean (SD) LPP (cmH2O) Mean (SD)
Study
Control
P
341.7 (107.7)
452.6 (168.3)
0.10
6.8 (1.5)
6.3 (2.3)
0.57
22.7 (8.0)
16.3 (4.4)
0.12
MCC, maximum cystometric bladder capacity; SD, standard deviation.
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TABLE II. Mean and Peak Pressure of Each Segment in Static and Dynamic Conditions Study Static (cmH2O) Bladder Mean 1.4 Peak 3.6 Proximal conduit Mean 7.6 Peak 12.5 Distal conduit Mean 27.1 Peak 48.6 Dynamic (cmH2O) Bladder Mean 21.0 Peak 27.7 Proximal conduit Mean 22.8 Peak 30.0 Distal conduit Mean 72.9 Peak 128.7 Increase in conduit’s distal pressure Mean 45.8 Peak 86.3
Control
P
1.2 3.7
0.73 0.94
6.1 12.2
0.71 0.79
31.4 51.0
0.61 1.00
24.0 29.5
0.42 0.69
21.1 25.0
1.00 0.68
48.3 65.1
0.0499 0.0126
16.9 20.0
0.003 0.022
Median.
filled were observed in both groups. In Study Group, at rest, mean and peak bladder pressure were 1.4 and 3.6 cmH2O, respectively, while in Control Group the results were 1.2 and 3.7 cmH2O (P ¼ 0.73 and P ¼ 0.94), respectively. In all cases, pressure in the conduit’s proximal segment was higher than the bladder pressure in both groups. In Study Group, at rest, mean and peak conduit’s proximal segment pressure were 7.6 and 12.5 cmH2O, respectively, while in the Control Group the results were 6.1 and 12.2 cmH2O (P ¼ 0.71 and P ¼ 0.79), respectively. Conduit’s distal segment pressure was in all cases higher than the conduit’s proximal segment pressure in both groups. In Study Group, at rest, mean and peak conduit’s distal pressure were 27.1 and 48.6 cmH2O, respectively, while in the Control Group the results were 31.4 and 51.0 cmH2O (P ¼ 0.61 and P ¼ 1.00), respectively. Dynamic Conduit’s Pressure Profilometry
During Valsalva maneuver, there was no statistically significant difference in bladder or conduit’s proximal segment pressure between groups. In Study Group, bladder mean and peak pressure were 21.0 and 27.7 cmH2O, respectively, while in Control Group the results were 24.0 and 29.5 cmH2O (P ¼ 0.42 and P ¼ 0.69), respectively. In Study Group, mean and peak pressure in conduit’s proximal segment were 22.8 and 30.0 cmH2O, respectively, while in Control Group the results were 21.1 and 25.0 cmH2O (P ¼ 1.00 and P ¼ 0.68), respectively. In the other hand, there was a statistically significant difference in conduit’s distal segment pressure between Control and Study groups with both mean and peak pressure analyzed. In Study Group, during Valsalva maneuver, the mean and peak pressure in the conduit’s distal segment were 72.9 and 128.7 cmH2O, respectively, while in Control Group the results were 48.3 and 65.1 cmH2O (P ¼ 0.0499 and P ¼ 0.0126), respectively. Boxplots of the difference found in conduit’s distal segment are shown in Figure 3(A and B). Neurourology and Urodynamics DOI 10.1002/nau
Difference Between Static and Dynamic Conduit’s Distal Pressure
The difference between values of static and dynamic conduit’s distal pressure represents how much elevation occurred in distal pressure with Valsalva maneuver. This increase in distal pressure was significantly higher in the Study Group when compared to Control Group (P ¼ 0.003) as shown in Table II. This difference was statistically significant when both mean and peak pressure were analyzed as shown in Figure 3(C and D).
DISCUSSION
The history of the development of bladder diversion demonstrates the intense search for the best combination of reservoir, conduit, and continence mechanism in an attempt to obtain good capacity, easy access through catheterization and quality of life, essential items to ensure the success of the procedure. The numerous options available in the literature and the number of articles being published uninterruptedly with new surgical approaches show that an ideal, universal, and reproducible procedure has not yet been found.17 Yachia published two articles using the crossed rectus abdominis strips as the only mechanism of continence and reported 100% of continence rate in both.18,19 According to the author, he found an increased pressure at the muscle level, especially during abdominal contraction. However, none of the papers presented the data or the techniques how the pressure profile was obtained. Hinman,16 in his study on the functional classification of the conduits, cites a possible contribution of the abdominal wall in continence, by constriction of the conduit, even without performing any local procedure. Only one controlled study would determine the real contribution to the pressure exerted on the conduit caused by the crossed muscle strips. Conduit’s LPP in the Study Group was higher than in Control Group, 22.7 and 16.3 cmH2O, respectively, but this difference was not statistically significant. There was no correlation between LPP and pressures found in the conduit at rest. Due to the unavailable urethral access or urethral urine leakage in some patients, samples were reduced and the analysis of this parameter was impaired. An increase in pressure, even at rest, at the level of the abdominal wall musculature from 10–25 to 45–60 cmH2O, when patients pass from supine to the upright position has been reported.19,24 Such behavior would be expected due to the muscle tonus needed to keep the patient upright and could represent a component in preserving continence. Possibly the Yachia’s mechanism could cause a greater increase in pressure. However, due to significant motor deficit of the lower limbs, which greatly hindered patient’s postural control, we were unable to perform the exam in this position. Control Group presented mean current age of 15 years, while in the Study Group it was 10.5 years, a statistically significant difference (P ¼ 0.006). That was one of our concerns but our feeling was that older patients would have more strength and possibly would be able to perform more efficient Valsalva maneuver. But that was not observed in the pressures measured inside the bladder. Both groups achieved similar bladder pressures and in fact the younger group presented higher distal efferent segment pressures under Valsalva. We had two populations with an age difference between them. We designed a study with the highest level of evidence possible using the available population and to our knowledge this is the only evidence available to date. Watson et al.25 published a study comparing appendix, ureter, ileum, and stomach conduit’s pressure in children. They
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Fig. 3. (A and B) Boxplots of the difference found in conduit’s distal segment during Valsalva’s maneuver between Study and Control groups. A, difference in distal mean pressure; and B, difference in distal peak pressure. (C and D) Boxplots of the difference found in the increase in conduit’s distal segment during Valsalva’s maneuver between Study and Control groups. C, difference in the increase in distal mean pressure and; D, difference in the increase in distal peak pressure.
found that the functional profile length, defined as the length of the conduit over, which conduit pressure remained greater than reservoir pressure, was correlated to continence when greater than 2 cm. The authors associated this measure to the intramural tunnel but did not mention the abdominal wall as an area of increased pressure. Our results demonstrated that the abdominal wall was capable of exerting a pressure of 25– 30 cmH2O above the bladder pressure, regardless of the presence of the intersection of the muscle strips. The pressure in the proximal portion of the conduit, presumably the site of the serous tunnel was also higher than the bladder pressure, with a difference of 5–6 (mean) and 9 (peak) cmH2O. Thus, the location of higher pressure and therefore with greater contribution to continence at rest was the abdominal wall in both groups. The distal portion of the conduit is presumably the abdominal wall and the crossed muscle strips site. During Valsalva maneuver, pressure at this site was significantly higher in the Study Group. We also compared the increase in conduit’s distal pressure in both groups. Some patients had a Neurourology and Urodynamics DOI 10.1002/nau
high distal pressure at rest, possibly justified by areas of narrowing of the canal. In Valsalva, these pressures remained elevated but not because of a muscular component. When we assessed the increase in conduit’s distal pressure, from static to dynamic condition, we naturally evaluated the increment of pressure obtained by muscular contraction. In the Control Group, the increase in conduit’s distal pressure was proportional to the increase in bladder pressure, while in the Study Group the rise in distal pressure was greater than the increase in bladder pressure. We can attribute this increase to the only factor that differentiates the two groups: the crossed rectus abdominis strips. CONCLUSIONS
Our study supports the use of Yachia’s technique as a continence mechanism enhancing the pressure inside the urinary conduit and therefore representing an extra barrier against urinary leakage. Crossing muscle strips over the conduit
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significantly increases the pressure in its distal segment during contraction of the rectus abdominis muscle. This mechanism may be especially important in order to keep continence during moments of sudden increase in abdominal pressure such as movement, coughing and sneezing, when abdominal muscles contract reflexively. REFERENCES 1. Lapides J, Diokno AC, Silber SJ, et al. Clean, intermittent self-catheterization in the treatment of urinary tract disease. J Urol 1972;107:458–61. 2. Mitrofanoff P. Trans-appendicular continent cystostomy in the management of the neurogenic bladder. Chir Pediatr 1980;21:297–305. 3. Monti PR, Lara RC, Dutra MA, et al. New techniques for construction of efferent conduits based on the Mitrofanoff principle. Urology 1997;49:112–5. 4. Sanda MG, Jeffs RD, Gearhart JP. Evolution of outcomes with the ileal hydraulic valve continent diversion: Reevaluation of the Benchekroun catheterizable stoma. World J Urol 1996;14:108–11. 5. Rowland RG. Present experience with the Indiana pouch. World J Urol 1996;14:92–8. 6. Xu YM, Qiao Y, Wu DL, et al. Efferent tube suspension as a continent diversion mechanism: A preliminary report of a clinical study. J Urol 2002;168:2027–9. 7. Tekant G, Emir H, Eroglu E, et al. Catheterisable continent urinary diversion (Mitrofanoff principle)—Clinical experience and psychological aspects. Eur J Pediatr Surg 2001;11:263–7. 8. Riedmiller H, Burger R, Muller S, et al. Continent appendix stoma: A modification of the Mainz pouch technique. J Urol 1990;143:1115–7. 9. Narayanaswamy B, Wilcox DT, Cuckow PM, et al. The Yang-Monti ileovesicostomy: A problematic channel? BJU Int 2001;87:861–5. 10. Mor Y, Kajbafzadeh AM, German K, et al. The role of ureter in the creation of Mitrofanoff channels in children. J Urol 1997;157:635–7. 11. Krstic ZD. Preputial continent vesicostomy: Preliminary report of a new technique. J Urol 1995;154:1160–1. 12. McAndrew HF, Malone PS. Continent catheterizable conduits: Which stoma, which conduit and which reservoir? BJU Int 2002;89:86–9.
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