Stesura Seveso Archivio Italiano di Urologia e Andrologia 2024; 96(2):12395 1 ORIGINAL PAPER INTRODUCTION Continent cutaneous diversion has proven to be an effec- tive way of urinary diversion. Yang-Monti ileovesicostomy technique uses ileal segment as a conduit instead of appendix as originally described in Mitrofanoff principle if appendix is not accessible. Urodynamic is a clinical test or a series of clinical tests used to describe the current function or dysfunction of the lower urinary tract. In the- ory and in practice, the clinician utilizes the results of urodynamic testing to direct therapy whether surgical, medical, or behavioral alone or in combination. Current methods include water filled urodynamic, ambulatory urodynamic, and video urodynamic. Regardless of the method, urodynamic examines the functional anatomy of the bladder or urethra or both and their response to fill- ing, storing, and voiding (1). Urodynamic testing is an important tool in urology providing objective descrip- tions concerning the patient’s incontinence and voiding dysfunction (2). Therefore, the objectives of this study was to analyze the static and dynamic urodynamic parameters of the reservoir and conduit affecting conti- nence after continent cutaneous urinary diversion with catheterizable stoma using Yang-Monti technique. MATERIALS AND METHODS Between June 2018 and May 2023, 76 patients who had continent urinary diversion and catheterizable urinary stoma based on Mitrofanoff principle and Yang-Monti tech- Objective: To analyze the static and dynamic urodynamic parameters of reservoirs and continent conduits in continent cutaneous urinary diversion with catheterizable stoma. Materials and methods: 76 patients had augmented ileocysto- plasty or continent urinary diversion with catheterizable uri- nary stoma based on Mitrofanoff principle and Yang-Monti pro- cedure using subserous tunnel as continence mechanism. They were followed up for at least 6 months post-operatively for con- tinence through stoma and divided into two groups (continents vs non-continent) according to stomal continence. Both groups had urodynamic assessment performed via the stoma to assess reservoir capacity, pressure and contractions, efferent limb functional length, reservoir overactivity, static and dynamic maximal closure pressures and leak point pressure. Results: Continence rate was 87%. Continent group included 66 patients and incontinent group included 10 patients. In both groups at rest, the reservoir pressure after filling did not exceed 25 cm H2O. During peristaltic contraction, the pressure did not exceed 30 cm H2O and the duct remained continent. After Valsalva maneuver, the reservoir pressure increased up to 34 (+ 7.4) cm H2O and leakage occur in 10 patients (13%). Reservoir (wall) overactivity was recorded in 54 patients, with insignificant rise in intraluminal pressure during the contrac- tions. In both groups, the efferent tract closing pressure was always higher than the reservoir pressure. The mean of maxi- mal closing pressure at Valsalva was 82.5 (+ 4.18) cm H2O in the continent group and 61.66 (+ 8.16) cm H2O in the inconti- nent group. The mean functional length of the conduit was 4.95 + 1.62 in the continent group and 2.80 + 1.50 cm in the inconti- nent group. Conclusions: Urodynamic evaluation of continent catheterizable cutaneous stoma after Yang-Monti procedure has a practical significance. Functional length of the conduit seems to be the most influential factor for continence reflecting static & dynam- ic maximal closure pressure. Higher conduit closing pressure is associated with better continence. Contractions of the pouch The use of urodynamic to assess the mechanism of incontinence in patients with Yang-Monti based catheterizable cutaneous stomas M. Abdelwadood 1, Eman H. Ibrahim 2, 3, Tamer A. Abouelgreed 4, Yasser M. Haggag 5, Mohamed M. Yassin 1, Mohamed A. Elhelaly 4, El-Sayed I. El-Agamy 4, Basem Fathi 4, Salma F. Abdelkader 6, Sameh S. Ali 7, Naglaa M. Aboelsoud 8, Nasser Ramadan 9, Mohamed Sobhy 10, Tarek Gharib 11 1 Department of Urology, Faculty of Medicine, Ain Shams University, Cairo, Egypt; 2 Department of Biomedical Sciences, College of Medicine, Gulf Medical University, Ajman, UAE; 3 Department of Pathology Faculty of Medicine, Al-Azhar University, Cairo, Egypt; 4 Department of Urology, Faculty of Medicine, Al-Azhar University, Cairo, Egypt; 5 Department of Urology, Faculty of Medicine, Al-Azhar University, Asyut, Egypt; 6 Department of Radiology, Faculty of Medicine, Ain Shams University, Cairo, Egypt; 7 Department of Radiology, Sheikh Khalifa General Hospital, UAQ, UAE; 8 Department of Radiology, Faculty of Medicine, Al-Azhar University, Cairo, Egypt; 9 Department of Urology, NMC Royal Hospital, Sharjah, UAE; 10 Department of Surgery, Faculty of Medicine, Gulf medical University, Ajman, UAE; 11 Department of Urology, Faculty of Medicine, Benha University, Benha, Egypt. DOI: 10.4081/aiua.2024.12395 Summary and peristaltic contraction of the conduit has no effect on conti- nence mechanism. KEY WORDS: Incontinence; Urodynamic; Urinary diversion. Submitted 18 February 2024; Accepted 1 March 2024 Archivio Italiano di Urologia e Andrologia 2024; 96(2):12395 M. Abdelwadood, Eman H. Ibrahim, Tamer A. Abouelgreed, et al. 2 nique in the institution of the Authors were included in this study and prospectively studied and followed up post-oper- atively for continence through the stoma for a minimum of 6 months. The mean age of the patients at time of surgery was 19 years (5-59 years); 51 patients were males and 25 patients were females. The indications for continent diver- sion were (neurogenic bladder in 59 patients, bladder can- cer in 13 patients, and congenital anomalies in 4 patients). Sixty-one cases had augmented ileocystoplasty with a patch of detubularised ileum and 15 cases had their native blad- der replaced by intestinal reservoir. An ileal segment with average length of 45 cm was detubularised and used as a reconfigured spherical reservoir for the ileovesicostomy procedure. Surgery for bladder neck closure was performed in 37 patients of the augmented group. The patients were divided into two groups according to stomal continence. Both groups had ascending pouchography and urodynam- ic study assessment performed via the stoma to assess reservoir capacity, pressure and contractions, efferent limb functional length, overactivity, static and dynamic maximal closure pressures and leak point pressure. The assessment was performed 15 days after the withdrawal of anticholin- ergic drugs and treatment of urinary tract infection. The patients who presented with reflux are excluded. State of continence was documented at 6 months and every 3 months later till end of the study. Mean follow up period was 30.6 months (ranging from 9 to 48 months). Urodynamic study was performed using a trans-stomal 6 French dual catheter and a 14 French rectal balloon catheter for pouchometry and pressure profilometry of the efferent tract. The rate of filling used was 50 ml/minute and the capacity measured at sense of discom- fort or notice of leakage. The withdrawal of sensors was done with an electric arm at a speed of 2 ml/min. The static profile maximum closure pressure of the efferent limb was obtained by subtracting the baseline (empty) reservoir pressure from the maximum inner pressure of the efferent limb. The catheter was again passed into the reservoir and the side hole of the catheter was manually positioned at the point of the static profile maximal clo- sure pressure of the conduit. The pouch was filled and the response of the conduit pressure to a reservoir contrac- tion and/or abdominal strain (cough or Crede) was recorded. The presence of involuntary reservoir contrac- tions or conduit leak was noted. Abrupt increase in con- duit pressure without simultaneous changes in reservoir or abdominal pressure was considered evidence of peri- staltic activity of the conduit. The dynamic profile maxi- mal reservoir pressure was recorded, and dynamic profile maximal closure pressure of the efferent limb was derived by subtracting the greatest filling phase conduit pressure from simultaneous reservoir pressure. Leak point pres- sure, compliance and reservoir capacity were evaluated. The functional length of the efferent limb was defined as the continuous length of the efferent limb in which the pressure was higher than the reservoir pressure. Ethical approval and consent for participation All procedures performed in this study complied with institutional and/or national research council ethical stan- dards as well as the 1964 Declaration of Helsinki and its subsequent amendments or similar ethical standards. Protocols and written informed consent for all partici- pants were approved by the Research Ethics Committee of Thumbay University Hospital (affiliated with Gulf Medical University, REC #: 52/2018). Statistical methods Demographic data, reservoir capacity, functional length, closure pressures were reported using mean + standard deviation (SD). Differences in means were assessed by Student t test for significance. Correlation among the con- tinuous variables was analyzed using Pearson correlation coefficient. Dichotomous variables as continence status, contractions, functional length greater than 2.0 cm versus less were analyzed using Chi-square test. RESULTS Continence rate was 87%. Continent group included 66 patients and incontinent group included 10 patients. No major surgical complications or mortality observed in the study. Stomal complications were observed in 4 patients in form of stomal stenosis in 2 patients and diffi- cult catheterization in further 2 patients. Surgical revision was performed for 7 patients; in the 4 cases with stomal complications other than incontinence and in 3 cases with incontinence that were treated with injection of bulking agents with 2 successes and 1 failure after sub- mucosal injection of bulking agent. The rest of the incon- tinent group were managed by frequent catheterization. The capacity of the reservoir was 496.8 (+180.27) ml (range 100-900). It was smaller in the incontinent group without a statistically significant difference. In both groups, the reservoir pressure at rest after filling did not exceed 25 CmH2O; the mean value was 20.72+6.05 cmH2O with no significant difference between continent and incontinent groups (Table 1). Peristaltic contractions of the reservoir were noted in 6 cases. During contractions, the pressure did not exceed 30 CmH2O and the duct remained continent. After Valsalva maneuver, the reservoir pressure increased up to 41.4 CmH2O without significant difference between continence groups (Table 1) and leakage occur in 10 patients. All patients had positive static and dynamic maxi- mal conduit closure pressures. In every case the dynamic was greater than the static pressure reflecting a positive con- duit to reservoir pressure gradient as the reservoir was filled to its capacity. The mean static and dynamic maximal clo- sure pressures of the incontinent group were lower com- pared to those of the continent patients but the differences were not statistically significant (Table 1). In both groups, the efferent tract closing pressure was always higher than the reservoir pressure. The mean efferent closing pressure at Valsalva was 82.5 (+ 4.18) CmH2O in the continent group and 61.66 (+ 8.16) CmH2O in the incontinent group which demonstrated a highly significant difference (Table 1). Overactivity was recorded in 54 patients, with insignifi- cant rise in intraluminal pressure during the contractions (Table 2). The mean functional profile length of the conduit was 4.6 + 1.77 cm (ranging from 1.7 cm to 7.5 cm) and was correlated positively to continence status (Table 3). The mean functional length of the continent and incontinent groups were 4.95 (+1.62) cm and 2.80 (+1.50) cm respec- tively with a highly significant difference (Table 1). All the Archivio Italiano di Urologia e Andrologia 2024; 96(2):12395 3 Urodynamic post Yang-Monti based catheterizable cutaneous stomas patients with conduit functional profile length of 2 cm or less were incontinent. Further analysis of patients with functional length lower than 2 cm revealed a lower static profile maximal closure pressure compared to those with a functional profile length of greater than 2 cm. Also, func- tional length was positively correlated to dynamic closure pressure (Table 4). Conduit peristalsis was observed in 29 patients. However, there was no statistically significant dif- ference between incidence of conduit peristalsis in conti- nent (23 patients/66) and incontinent (6 patients/10), by the measurement of functional profile length, static or dynamic maximal closure pressure (Table 5). In our study, one patient was managed by surgical elonga- tion of the tunnel and become completely dry on five hours interval between catheterization. DISCUSSION Mitrofanoff principle was described to achieve continent urinary diversion through an appendiceal stoma in cases of compromised vesico-urethral function with inaccessi- ble urethra (3). An alternative approach (Yang-Monti tech- nique) using an opened ileal segment closed transversely was described later when the appendix could not be used or preserved for Malone antegrade enema procedure (MACE) (4). The Monti ileovesicostomy has become an integral component of lower urinary tract reconstruction and more recently laparoscopic and robotically assisted techniques have been described also (5, 6). In the present study, the continence rate was 87%, that is lower than those achieved by studies which used appendi- covesicostomy with continence rates ranging from 91 to 96% (7-9). Other studies on Monti technique suggested continence rates comparable to appendicovesicostomy (10). This result may be attributed to the high conduit intraluminal pressure achieved by appendiceal stoma (11) or inadequate surgical technique as inadequate flap valve mechanism, internal fistula or inadequate reservoir (12). The reservoir capacity was adequate in most cases with a mean cystometric capacity at 6 months of 496 ml due to detubularisation. Smaller reservoir capacity was observed in incontinent group but without statistical significance, although seven patients of the incontinent group showed a capacity of 250-300 ml. These patients had to catheterize their pouch every two hours to avoid urine leak and dur- ing nighttime, an indwelling catheter had to be placed to avoid sleep interruption. The incontinence in the other three patients with adequate capacity can be explained by insufficient tunnel length, inadequate fixation of efferent channel to rectus sheath or angulation. One patient was managed by surgical elongation of the tunnel becoming completely dry at five hours interval between catheteriza- tions. Two cases were managed by submucosal injection of bulking agent which achieved temporary continence only for 2 months and required subsequent revision of the con- duit to regain continence. These results support poor results observed in literature for bulking agent injection in ileal stomal incontinence (13, 14). Stomal complications in this study were minimal (5.2%) in comparison to results of appendicovesicostomy observed in literature (15) and bet- ter than reports of other studies that suggested same rate of stomal complications for Monti technique compared to appendicovesicostomy (11 to 19%) (10). The urodynamic study at rest showed low reservoir pressure due to detubu- larisation which delays and reduces the amplitude of the pressure rise caused by partial contractions and conse- quently accommodates higher volumes and prevents leak- age. Detrusor overactivity was detected in many patients but did not cause a significant rise in the reservoir pressure or associated leakage. The conduit pressure was an impor- tant factor contributing in efficacy of continent catheteriz- able stomas, being the higher the conduit pressure, the more the continence mechanism. The mean static and dynamic closure pressure of the conduit were lower in Table 1. Urodynamic data of the continent group in comparison to incontinent group. Continent group Incontinent group p-value Reservoir capacity 500.95 + 182.64 ml 475.00 + 191.92 ml 0.79 Reservoir pressure after filling 18.92 + 5.08 CmH2O 21.72 + 3.05 CmH2O 0.8 Reservoir pressure after Valsalva 30 + 5.6 CmH2O 34 + 7.4 CmH2O 0.86 Efferent closing pressures 82.50 + 4.18 CmH2O 61.66 + 8.16 CmH2O < 0.001 Functional length 4.95 + 1.62 cm 2.80 + 1.50 cm < 0.001 Static maximal closure pressure 46.50 + 12.66 38.90 + 10.12 0.197 Dynamic maximal closure pressure 68.75 + 8.53 66.90 + 11.88 0.771 Table 2. Intraluminal pressure in contracted reservoir versus non-contracted. Groups No. of patients Mean pressure + SD p value No contractions 54 19.8 + 6.58 0.363 Reservoir contractions 22 22.1 + 5.17 Table 4. Correlations between functional length and maximal closure pressure. Dynamic Static Functional length r .522** .056 p value .007 .790 N 25 25 Table 5. Conduit peristaltic contraction in relation to urodynamic data. Groups Mean + SD t p value Static No peristalsis 38.41+ 9.238 0.76 0.45 Peristalsis 41.69 + 11.967 Dynamic No peristalsis 66.66 + 11.934 0.22 0.82 Peristalsis 67.69 + 11.108 Functional length No peristalsis 4.26 + 2.039 092 0.36 Peristalsis 4.92 + 1.497 Table 3. Correlation between functional length and continence status. Functional length Continence Pearson correlation 0.454 * 1 Significance (2-tailed) 0.22 * Correlation is significant at the 0.05 level. Archivio Italiano di Urologia e Andrologia 2024; 96(2):12395 M. Abdelwadood, Eman H. Ibrahim, Tamer A. Abouelgreed, et al. 4 incontinent cases but the difference was not statistically sig- nificant. These results are similar to the results achieved by other studies (11, 16). The efferent tract closing pressure (with full reservoir) in our study was 75 CmH2O. This result is similar to the result obtained by appendicovesi- costomy. However, most long-term studies supported durable results of appendicovesicostomy (11) where this is still to be proven for ileovesicostomy by future long term studies. The mean functional length was 4.6 cm and it showed a highly significant difference between continent and incontinent group. Although static and dynamic clo- sure pressures were not significantly different between con- tinent and incontinent groups, there was a significant cor- relation between functional length and the maximum clo- sure pressure. Thus, the cause of incontinence can be attributed to length of the conduit more than reservoir capacity. Strong peristaltic contractions of the conduits were demonstrated in some individuals but the overall effect of these pressure waves did not correlated with clin- ical continence or with any other urodynamic factor. CONCLUSIONS Urodynamic evaluation of continent catheterizable cuta- neous stoma after Yang-Monti procedure has a practical significance. Functional length of the conduit seems to be the most influential factor for continence reflecting static and dynamic maximal closure pressure. Higher conduit closing pressure is associated with better continence. Contractions of the pouch and peristaltic contraction of the conduit has no effect on continence mechanism. ACKNOWLEDGMENTS Thanks to Prof. Dr. Hossam Hamdy, President of Gulf Medical University for his suggestion. REFERENCES 1. Abouelgreed T, Saleh D, Abdelaal M, et al. Urodynamic changes following laparoscopic versus vaginal hysterectomy. Arch Ital Urol Androl. 2022; 94:315-318. 2. Kupec T, Pecks U, Gräf CM, et al. Size Does Not Make the Difference: 3D/4D Transperineal Sonographic Measurements of the Female Urethra in the Assessment of Urinary Incontinence Subtypes. Biomed Res Int. 2016; 2016:1810352. 3. Ramanan V, Kapoor R, Srinadh ES, et al. Mitrofanoff principle for continent urinary diversion.Urol Int. 1997; 58:108-112. 4. Monti PR, de Carvalho JR. Transverse tubulization of intestinal segments: a catheterizable conduit as an alternative to the Mitrofanoff procedure. Prog Urol. 2001; 11:382-384. 5. Thakre AA, Yeung CK, Peters C. Robot-assisted Mitrofanoff and Malone antegrade continence enema reconstruction using divided appendix. J Endourol. 2008; 22:2393-2396. 6. Wille MA, Zagaja GP, Shalhav AL, Gundeti MS. Continence out- comes in patients undergoing robotic assisted laparoscopic mitro- fanoff appendico-vesicostomy. J Urol. 2011; 185:1438-1443. 7. Elshal AM, Abol-Enein H, Sarhan O, et al. Catheterizable serous lined urinary outlet in children and adolescents: a choice when other treatments fail. J Urol. 2011; 185:1083-1087. 8. Mhiri MN, Bahloul A, Chabchoub K. Mitrofanoff appendicovesicos- tomy in children: indication and results. Prog Urol. 2007; 17:245-249. 9. Surer I, Ferrer FA, Baker LA, Gearhart JP. Continent urinary diver- sion and the exstrophy-epispadias complex. J Urol. 2003; 169:1102- 1105. 10. Clark T, Pope JC 4th, Adams mC, et al. Factors that influence outcomes of the Mitrofanoff and Malone antegrade continence enema reconstructive procedures in children. J Urol. 2002; 168:1537-1540. 11. Chabchoub K, Ketata H, Fakhfakh H, et al. Continent urinary diversion (Mitrofanoff principle). Physical mechanisms and urody- namic explanation of continence. Prog Urol. 2008; 18:120-124. 12. Cain MP, Andrew MD, Anthany JG, et al. Updated experience with the Monti catheterizable channel. Pediatric Urology 2008; 72:782-785. 13. Gowda BO, Agrawal V, Harrison SC. The continent catheteriz- able abdominal conduit in adult urological practice. BJU Int; 2008; 102:1688-1692. 14. Welk BK, Afshar K, Rapoport D, MacNeily AE. Complications of the catheterizable channel following continent urinary diversion: Their nature and timing. J Urol 2008; 180:1856-1860. 15. Van der AF, Joniau S, De Baets K, De Ridder D. Continent catheterizable vesicostomy in an adult population: success at high costs. Neurourol Urodyn. 2009; 28:487-4891. 16. Watson HS, Bauer SB, Peters CA, et al. Comparative urodynam- ics of appendiceal and ureteral Mitrofanoff conduits in children. J Urol 1995; 154:878-882. Correspondence Eman H. Ibrahim, MD (Corresponding Author) dr.eman@gmu.ac.ae Department of Biomedical Sciences, College of Medicine, Gulf Medical University, Ajman, UAE & Department of Pathology, Faculty of Medicine, Al-Azhar University, Cairo, Egypt M. Abdelwadood, MD - wadoodaref@gmail.com Mohamed M. Yassin, MD - yassinmmm@med.asu.edu.eg Department of Urology, Faculty of Medicine, Ain Shams University, Cairo, Egypt Tamer A. Abouelgreed, MD - dr_tamer_ali@yahoo.com Mohamed A. Elhelaly, MD - elhelalymohammed@yahoo.com El-Sayed I. El-Agamy, MD - abuamr1978@yahoo.com Basem Fathi, MD - basemhara@Gmail.com Department of Urology, Faculty of Medicine, Al-Azhar University, Cairo, Egypt Yasser M. Haggag, MD - uro_doc@yahoo.com Department of Urology, Faculty of Medicine, Al-Azhar University, Asyut, Egypt Salma F. Abdelkader, MD - salmafathy4@gmail.com Department of Radiology, Faculty of Medicine Ain Shams University, Cairo, Egypt Sameh S. Ali, MD - drsamehsaied@yahoo.com Department of Radiology, Sheikh Khalifa General Hospital, UAQ, UAE Naglaa M. Aboelsoud, MD - nglaa.mahmoud@gmail.com Department of Radiology, Faculty of Medicine, Al-Azhar University, Cairo, Egypt Nasser Ramadan, MD - nasseruro99@gmail.com Department of Urology, NMC Royal Hospital, Sharjah, UAE Mohamed Sobhy, MD - mss54482000@yahoo.com Department of Surgery, Faculty of Medicine, Gulf Medical University, Ajman, UAE Tarek Gharib, MD - tarekgh78@yahoo.com Department of Urology, Faculty of Medicine, Benha University, Benha, Egypt Conflict of interest: The authors declare no potential conflict of interest.