Defining the indications of PATIO technique for urethrocutaneous fistula repair

Prativa Choudhury; Shivani Phugat; Vishesh Jain; Devendra Kumar Yadav; Anjan Kumar Dhua; Vivek Verma; Ajay Verma; Sachit Anand; Sanchita Singh; Prabudh Goel

doi:10.4103/jiaps.jiaps_25_23



ORIGINAL ARTICLE

Year : 2023 \| Volume : 28 \| Issue : 5 \| Page : 375-386

Defining the indications of PATIO technique for urethrocutaneous fistula repair

Prativa Choudhury¹, Shivani Phugat¹, Vishesh Jain¹, Devendra Kumar Yadav¹, Anjan Kumar Dhua¹, Vivek Verma², Ajay Verma¹, Sachit Anand¹, Sanchita Singh³, Prabudh Goel¹
¹ Department of Paediatric Surgery, All India Institute of Medical Sciences, New Delhi, India
² Department of Biostatistics, Assam University, Silchar, Assam, India
³ Department of Health Research, Indian Council of Medical Research, New Delhi, India

Date of Submission	02-Feb-2023
Date of Decision	21-Feb-2023
Date of Acceptance	08-Mar-2023
Date of Web Publication	05-Sep-2023

Correspondence Address:
Prabudh Goel
Office 769, Mother and Child Block, All India Institute of Medical Sciences, New Delhi - 110 029
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jiaps.jiaps_25_23

Abstract

Introduction: Despite the advancements in technique and technology, urethrocutaneous fistula (UCF) formation continues to be the most common complication after hypospadias repair.
Objective: The objective of the current synthesis is to define the indications of PATIO technique for UCF repair.
Materials and Methods: The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, Scopus, Ovid, Embase, Web of Science, and Google Scholar were interrogated for studies presenting primary data upon UCF repair by the PATIO technique. Data analysis was performed on MedCalc and R software.
Results: Eighteen studies were identified relevant to the current context: inversion of UCF tract has been described in 13 and ligation in 5. There were 2 duplications (abstract and manuscript). The overall success for PATIO is 88.2% (314/356). The success rate was variable between classic PATIO (inversion at 87.2%), ligation-inversion at 86.9%, and ligation alone at 88.9%. The success rate was not improvised upon by supplementing inversion of UCF tract with ligation (p = 0.957) or addition of a waterproofing layer (p = 0.622). PATIO has been used for single or multiple UCFs post hypospadias repair, genital piercing, and genitoplasty in cis- or transgender population for UCF up to 5 mm in size. The success rates were best for UCF <2 mm and worst for those approaching 5 mm. The results were, however, unaffected by the location of UCF along the penile shaft. Besides, the use of urethral catheter is optional and may be eliminated with shorter hospitalization.
Conclusions: PATIO repair may be considered for repair of UCFs (a) with diverse etiologies, (b) located anywhere along the penile shaft included coronal UCF, (c) preferably <4 mm in size, (d) single or multiple in number; multiple PATIOs may be done in the same setting, (e) in patients unwilling for prolonged hospitalization, (f) in patients unwilling for a urethral catheter, and (g) in hypospadias cripples wherein mobilization of distant tissues such as tunica vaginalis flap or a buccal mucosal graft may be required for supplementing the UCF repair.

Keywords: Inversion of urethrocutaneous fistula, ligation of urethrocutaneous fistula, ligation-inversion of urethrocutaneous fistula, PATIO repair, urethrocutaneous fistula, waterproofing layer

How to cite this article:
Choudhury P, Phugat S, Jain V, Yadav DK, Dhua AK, Verma V, Verma A, Anand S, Singh S, Goel P. Defining the indications of PATIO technique for urethrocutaneous fistula repair. J Indian Assoc Pediatr Surg 2023;28:375-86

How to cite this URL:
Choudhury P, Phugat S, Jain V, Yadav DK, Dhua AK, Verma V, Verma A, Anand S, Singh S, Goel P. Defining the indications of PATIO technique for urethrocutaneous fistula repair. J Indian Assoc Pediatr Surg [serial online] 2023 [cited 2023 Sep 24];28:375-86. Available from: https://www.jiaps.com/text.asp?2023/28/5/375/385144

Introduction

There has been a gradual reduction in the complication rates associated with hypospadias repair with the refinement of surgical techniques, availability of finer suture material, optical magnification, and a deeper understanding of the surgical anatomy. However, urethrocutaneous fistula (UCF) formation continues to be the most common complication after hypospadias repair. It is as much a nightmare for the patient as the operating surgeon. The reported incidence is highly variable and fluctuates between 5% and 45%.^[1] Repair of the UCF implies repeat hospitalization, urethral catheterization, general anesthesia, the onslaught of surgery, and above all, the risk of repeat UCF formation.

A multitude of techniques, each scoring superior to the previous ones, have been described in the literature, yet neither of them is far from perfection. Simple closure has evolved into multi-layered techniques, dartos flaps have been doubled, dermal substitutes and tissue glues have been deployed, yet the problem of UCF stares unresolved. The results are dependent upon multiple factors which may be stratified into those related to surgery (technique and suture), surgeon (finesse, experience, and expertise), and the patient (local anatomy). Amid this confusion, the PATIO (preserve the tract and turn it inside out) technique is relatively simple and less cumbersome for both the patient and the surgeon.

The earliest description of PATIO dates back to 1940, although the term 'PATIO' was coined later.^[2] The technique [depicted diagrammatically in [Figure 1]] has been evaluated in more than ten studies across the globe [Figure 2] and ligation of fistula without inversion in another five studies. The current systematic review and meta-analysis is an attempt to identify the UCF best addressed by PATIO repair.

Figure 1: Pictorial depiction of the (a) classic PATIO technique (the UCF tract is meticulously dissected from the skin down to the urethral wall and inverted into the urethral lumen. The tract is kept aligned in the direction of the urinary stream). (b) Modified PATIO wherein the tract is ligated at the base in addition to inversion into the urethral lumen, (c) Ligation of the UCF base only. PATIO: preserve the tract and turn it inside out, UCF: Urethrocutaneous fistula

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Figure 2: Depiction of the geographic location of the publications on PATIO. [1: Michigan, USA. 2: Essex, UK. 3: Berks, UK. 4: Belgaum, India. 5: Reading, UK. 6: Leicester, UK. 7: Eschweiler, Deutschland. 8: Manitoba, Canada. 9: London, UK. 10: Barcelona, Spain. 11: New York, USA. 12: Manitoba, Canada. 13: New York, USA. 14: Jeddah, Saudi Arabia. 15: Gaziantep, Turkey. 16: Shiraz, Iran. 17: London, UK. 18: Hangzhou, China.]

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Materials and Methods

The idea was conceived by the corresponding author, and a team comprising a hypospadiologist, pediatric surgeons, biostatistician, epidemiologist, scientist, and experts in systematic reviews and meta-analysis was organized. None of them had any conflict of interest. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were adhered to during the review process.^[3]

Search strategy

The presence of another review on the same topic was excluded. PubMed/PubMed Central/PMC databases, Scopus, Ovid, Embase, and Web of Science were interrogated with the search terms “hypospadias,” “urethro-cutaneous fistula,” “PATIO,” “ligation,” and “inversion” using the Boolean approach (and operators “AND” and “OR”). Search results were supplemented by results from Google search engine, Google Scholar, snowballing, and reverse snowballing. Initially, the search was restricted to publication after 2009 based on the publication by Malone;^[4] based on the results of reference searching, it was realized that the technique was first described in 1940 and the restrictions pertaining to the year of publication were eliminated. There were no restrictions related to the age of participants, language of publication, or etiology of UCF. Search was conducted in duplicate, and results were collated. The search strategy and results have been outlined in the PRISMA flow diagram [Figure 3].

Figure 3: PRISMA flow diagram outlining the search strategy and results. PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-Analyses

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Inclusion criteria

Studies presenting primary data based on the results of UCF repair by the PATIO technique were included in the analysis. Similar data by the same authors in the manuscript and published abstracts were highlighted to avoid duplication.

Data extraction

Data were extracted by two independent reviewers into Excel sheets (Microsoft Excel for Mac version 16.9.1) and collated. The discrepancies were resolved by verification with source and consensus in the presence of the senior author. The methodological quality of each included study was assessed with the Joanna Briggs Checklist (JBI) critical appraisal tools. However, considering the study design and limited data availability, none of the studies were excluded from the analysis on the basis of the JBI score.

Statistical analysis

Data analysis was done using the formula function in Excel; MedCalc® Statistical Software version 20.106 (MedCalc Software Ltd., Ostend, Belgium; https://www.medcalc.org; 2022) was used for single-arm meta-analysis with the random effects model, and R software (4.2.2) was used for Bayesian estimation. Heterogeneity (I²) was tested across the studies included in the review, and the 95% confidence interval (CI) was calculated. Begg's and Egger's tests were applied to the funnel plot analysis for the identification of publication bias.

Results

Literature search was congruent with the facts that purse-string ligation of the UCF was proposed by Dieffenbach.^[5] Davis^[2] modified the procedure to include inversion of the UCF tract into the urethral lumen and reported a complete cure in three troublesome UCFs. The same technique has been adopted and reported by many in the 20^th century^[6],[7],[8] in discrete, single-author publications. Beyond hypospadias, the concept has been utilized for the repair of vesicovaginal and laryngeal fistulae.^[5],[9] The term PATIO was used by Malone in 2009^[4] as an acronym for Preserv/e(-ing) the (UCF) Tract and Turn(-ing) it Inside Out. Malone's description of the procedure does not include ligation of the UCF tract. Based on this understanding, the authors have included studies deploying inversion of the UCF with or without ligation of the UCF base. Techniques limited to ligation of the UCF base without actual inversion into the urethra have also been included for analysis.

Eighteen studies have been short listed for evidence synthesis of which inversion of the UCF tract has been described in 13 only.^{[4],[7],[8],[10],[11],[12],[13],[14],[15],[16],[17],[18],[19],[20],[21],[22],[23],[24]} The other five studies have described single (n = 3) and double ligation of the UCF tract (n = 2). Two entries each were identified for Kranz et al. and Singh et al.; chronologically, the first one (Kranz et al., 2015, and Singh et al, 2018) was abstracts only while the later one^[10],[24] was complete studies, respectively. The data from the respective abstracts have been eliminated from the final calculations to avoid duplication. The studies represent only 3/7 continents across the globe (Asia: 5, Europe: 7, and North America: 4) [Figure 2]. The study characteristics are summarized in [Table 1].

Table 1: Outline of characteristics specific to studies included in the synthesis

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The analysis is based on 356 patients in 16 studies. Of these, 12/16 (75%) have been published over the last 10 years and 8/16 (50%) over the last 5 years. There are at least 2 prospective and 7 retrospective study designs. Besides, there are case series (n = 2) and case report (n = 1) in the study. In addition to hypospadias, the cohort includes cis-and trans-gender patients as well as patients who develop UCF consequent to genital piercing. The most common location for UCF in the pooled cohort is coronal (n = 123 at least); the others were distal (n = 88 or more), mid-shaft (n = 31 or more), and proximal (n = 32 or more) UCFs in the series.

The pooled success within the cohort is 88.2% (314/356). Six of 16 studies have reported absolute 100%success (54 patients).^{[4],[8],[12],[13],[20],[22]}

The classic PATIO (inversion of UCF tract) repair has been performed in 6 studies (n = 47 patients, 87.2% success). Among these, the PATIO was supported by a waterproofing layer in a selected group of patients in only 2 studies [Figure 5]. Nerli et al.^[12] used a tunica vaginalis flap when the UCF was large (2–4 mm) while Stair et al.^[18] used dartos interposition for patients undergoing repeat PATIO after the first PATIO had failed. Using the two-sample independent proportion test, the results of inversion of the UCF tract were not improvised upon by the addition of a waterproofing layer (p =0.174 at α = 0.05). Ligation of the UCF tract followed by inversion has been described in 5 studies (n = 84 patients; 86.9% success) [Figure 5]. Among these, the PATIO was supported by dartos/local subcutaneous tissue in 2 studies (n = 24 patients; 79.16% success) and by a local transposition skin flap in 1 study (n = 20; 100% success) [Table 1]. No waterproofing layer was interposed in 2 studies (n = 40 patients; 85% success). The proportion of success was not improvised by the addition of another cover (p = 0.622 at α = 0.05). Ligation of UCF prior to inversion does not yield results superior to those with inversion alone (p = 0.957 at α = 0.05).

Figure 5: Proportional success rates with respective confidence intervals, the pooled results and forest plots for [a] Studies reporting on Classic PATIO repair, [b] Studies reporting on Ligation-Inversion of UCF tract, and [c] Studies reporting on Ligation of UCF tract without Inversion, [d] Funnel Plot for all included studies.

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Ligation of the UCF tract without inversion has been described in 5 studies (n = 225; 88.9% success) and did not score superior to inversion alone (p = 0.745 at α = 0.05) or ligation followed by inversion (p = 0.629 at α = 0.05). The results of single ligation (3 studies; n = 66; 93.9% success) were superior to those of double ligation (2 studies; n = 159 patients; 85.5% success): p = 0.013 at α = 0.05. Jamal et al.^[20] fulgurated the epithelium of the UCF stump and buried it under local subcutaneous soft tissue with the tip directed proximally (reverse of PATIO). In all these studies, the ligated UCF tract was supported by dartos (n = 67 patients; 3 studies; 95.5% success) or local subcutaneous tissue (n = 12 patients; 1 study; 100% success) for waterproofing. Yang et al.^[15] (n = 145; 84.9% success) used either dartos or tunica vaginalis flap (stratification not available).

Size of urethrocutaneous fistula

The PATIO technique has been applied to UCF <5 mm only. Within the pooled cohort, data pertaining to the size of UCF are not available for 5 studies.^{[4],[7],[8],[10],[13]} UCF <5 mm has been included in three studies^{[14],[15],[16]} with 84.4% success (26/167 failures). In Yang et al., there was only 1 patient with a UCF size >4 mm; the UCF was coronal in location and was managed successfully with double ligation. Xu et al.^[14] included 2 such patients with failure in 1/2 (pooled success for UCF >4 mm: 66.7%: 2/3). UCF <4 mm has been included in 4 studies^{[12],[17],[18],[19]} with 89.5% success (8/76 failures). The results of PATIO on UCF <3 mm have been reported in 2 studies (Stair et al,^[18] Moreno et al,^[22]) with 85.3% success (5/35 failures). Moreno et al. ^[22] have published their successful experience with a single case post 3 previous hypospadias surgeries. The patient had a single, 2-mm UCF in the balanopreputial groove which was repaired by PATIO followed by a two-layered skin closure. UCF <2 mm has been included in 2 studies^[20],[21] with 96% success demonstrated in the pooled cohort (1/25 failures).

The efficacy of the technique for different sizes of UCF was compared by using a compound beta-binomial model. The Bayesian method-derived estimates for multi-level UCF measurement-based assessment are depicted in [Figure 4]. The results of UCF inversion were superior to those of fistula ligation. The best results for inversion of the UCF tract are witnessed for UCF <4 mm.

Figure 4: Bayesian method-derived estimates for multi-level UCF measurement-based assessment. (a) Bayesian estimates of success rate for overall patients in cohort (red line), UCF inversion (blue line), and ligation of UCF (green line). (b) Classification of UCF based on size; an understanding of the Bayesian methodology. (c) Classical and Bayesian estimates with confidence intervals. UCF: Urethrocutaneous fistula

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The proportional success rates for individual studies with respective CIs, the pooled results, and the forest plot are provided in [Figure 5]. The publication bias was estimated with the funnel plot as well as the Egger's and Begg's tests.

Location of urethrocutaneous fistula

The UCFs were coronal (n = 44), distal penile (n = 106), mid-penile (n = 16), and proximal (n = 10) in location. The success for coronal UCF was comparable to the overall success (p = 0.850 at α = 0.05) as well as to those of noncoronal UCF (p = 0.826 at α = 0.05). Similarly, there were no differences in the success rates for distal (including coronal) UCF as compared to the pooled cohort (p = 0.753 at α = 0.05) or UCF in other locations (p = 0.575 at α = 0.05).

Discussion

The surgical technique mandates dissection of the UCF tract up to the urethral wall, and inversion of the tract into the urethral lumen creates a passive “flap-valve” like mechanism. The tract is maintained in an inverted configuration by a suture secured to the tip of the glans or otherwise. The direction of the tract is along the urinary stream which compresses and flattens the UCF tract against the wall of the urethra like a “flap valve” to prevent urinary leak/recurrence of fistula. The use of urinary diversion may be avoided, thereby reducing the hospital stay. Suturing the radix or the base of the UCF serves as an additional mechanism to contain the urinary stream inside the urethral canal. The technique does not preclude the use of an interposing “waterproofing” layer and other mechanisms considered instrumental in reducing the possibility of recurrence such as the use of bioadhesives over the repair or advancement of skin flaps. The usefulness of the technique has been demonstrated for UCF with different etiologies.^{[4],[14],[18]} More than one UCF along the penile shaft may also be repaired simultaneously. UCFs with a history of failed PATIO may be repaired with repeat PATIO repairs.^{[14],[17],[18]}

The dissection of the fistula tract has to be very meticulous. In case, there is a buttonhole in the wall of the UCF tract during its dissection, and the possibility of failure of the procedure is increased. This caution has been highlighted by Malone and Nerli et al.^[4],[12] This is more likely in cases, wherein the buttonhole is close to the radix of the UCF tract and in those cases wherein the inversion of the UCF tract is not supported by ligation or a waterproofing layer.

The longer the length of the UCF tract, the more effective the flap-valve mechanism is likely to be. This is an extrapolation of the understanding gained from the vesicoureteric junction wherein the length and obliquity of the intravesical ureter are important.^[25] Sometimes, the length of the UCF tract is too brief for several reasons, (a) the penis lacks subcutaneous tissue, (b) the spongiosum may be deficient in hypospadias, and (c) the spongiosum may have dehisced too as an integral component of the infective (or other) processes leading to the formation of UCF. The length of the UCF tract may be increased by 1–2 mm by increasing the diameter of the incision around the UCF to include adjacent skin alongwith the UCF tract in order to augment the passive flap-valve mechanism.

The stump is held in the desired position with the help of a suture secured to the glans or fixed by an Angler lead.^[10] Conger^[7] brought the ends of the thread out of the urethra at a point about ½ inch from the fistula through the skin, where they are tied to each other. This is equivalent to creating another UCF and risking the possibility of a complication in the future; the authors are in favor of tying the thread to the tip of the glans as in the case of urethroplasty wherein the urethral stent is secured. The authors have followed the same protocol in their unpublished series of 13 cases with a single recurrence.

Although this technique has been around for more than seven decades, it has been reported across 3 continents only. Most of the publications belong to the last 5 (~50%) or 10 years (~75%). The results of the technique have been reported across 356 patients across the globe. Considering the prevalence of hypospadias and the high incidence of UCF formation post hypospadias repair, it is evident that the technique never gained popularity despite a promise of 88% overall success. PATIO is different from all other techniques of UCF repair and incorporates a unique style of dissection and methodology. The procedure has to be planned at the time of starting the surgery, and the results may be limited by the learning curve. However, it offers multiple advantages when successful. The use of a urinary catheter may be avoided. The surgery may be performed as a day-care procedure. The operating time is brief and so is the local dissection unless a waterproofing layer is contemplated.

The technique offers uniform results for UCF located anywhere along the penile shaft. As expected, the most common location for UCF is distal penile. The distal penile UCF (inclusive of those, coronal in location) accounts for 85% of the cases in the pooled cohort. The results of the technique for coronal UCF were not different from those for the pooled cohort as well as for those UCFs which were noncoronal in location. The same is true for UCF distal penile in location. This finding gels well with the understanding of the technique since this is not dependent upon the location of the UCF. However, the length of the thread(s) used to keep the UCF tract aligned along the urinary stream will be longer for proximal UCF. For those who prefer ligation in addition to inversion of the tract, the process of intraurethral knotting may be more, however tedious for proximal UCF.

The pooled cohort consists of 6 studies wherein the inversion of the UCF tract has been completed as an isolated procedure. In another 5 studies, the inversion of UCF has been supplemented with ligation of the UCF tract. The results were similar in the two groups signifying that the ligation of the UCF at its base does not add value to the procedure. Inversion of the tract is good enough. The flap mechanism created by the wall of the UCF tract is self-sufficient in containing the extravasation of urine out of the urethra. Moreover, those cases wherein the PATIO repair was not successful must be evaluated for factors other than suturing of the urethral defect. A breach in the integrity of the fistula wall during dissection of the UCF tract or incomplete inversion of the UCF tract or improper alignment of the UCF tract may be important considerations.

Supplementing the PATIO with a waterproofing layer to prevent recurrent of UCF did not make a discernible difference in the final outcomes. Herein, the effectiveness of the flap-valve mechanism is re-authenticated. When the PATIO flap valve is not able to contain the leak of urine, even the waterproofing layer does not help. Single or double ligation of the UCF tract in the absence of inversion has also been studied, and the results were not superior to those of the PATIO repair.

The size of the UCF has been an important consideration for most of the studies included in this series. Jamal et al. and Karakus et al.^[20],[21] have included UCF <2 mm only in their series while Xu et al., Yang et al., and Misra et al.^{[14],[15],[16]} have explored the utility of PATIO up to 5 mm. Bayesian method-derived estimates have depicted that the proposed surgical procedure is most effective for UCF <4 mm, with the best results reported for UCF <2 mm. While the edges of the UCF are approximated, there is a reduction in the circumference of the urethra at the site of UCF which ought to be more than the transverse width of the UCF in view of fibrosis during healing. If the urinary flow were laminar and other factors constant, a 20% reduction in the circumference of the urethra will lead to a 2.44-fold increase in the resistance to urinary flow at the site of repair. This is because the resistance in laminar flow is inversely proportional to the fourth power of the radius. A decrease in the diameter of the urethra by 50% would result in a sixteen-fold increase in resistance. Besides, the inverted UCF tract will increase the turbulence in the urinary stream (Poiseuille's law).^[26] Hence, the PATIO repair is not suitable for larger UCFs. Furthermore, the larger the size of UCF, the larger is the caliber of the UCF tract. Hence, the larger is the length of the tract required for it to prevent upstream reflux of urine (extrapolation from antireflux mechanism at the vesicoureteric junction).

However, the following general principles apply to PATIO as well as (a) ascertain the number and site of UCFs and (b) ascertain the absence of meatal stenosis or urethral stricture as part of workup or on-table assessment. During surgery, it is very important to ensure (a) dissection of the UCF tract without damage to the integrity of its wall, (b) that the entire length of the UCF is free from surrounding tissues which are likely to be fibrotic and (c) inversion of the UCF tract into the urethral lumen and alignment of the tract toward the urinary meatus. The study is limited by its (a) small sample size in most of the studies, (b) limited number of studies included in the synthesis, (c) lack of randomized controlled trials comparing other techniques, (d) lack of data enough to facilitate multivariate logistic regression, and (e) lack of standardized format for reporting results for UCF repair.

Conclusions

Based on the insights provided by this synthesis, the PATIO repair may be considered in cases (a) with diverse etiologies such as UCFs post hypospadias repair, genital piercing, or genitoplasty in cis- or transgender population, (b) located anywhere along the penile shaft including those coronal in location (with no significant difference in expected outcomes based on UCF location), (c) preferably <4 mm in size, (d) single or multiple in number; multiple PATIOs may be done in the same setting, (e) in patients unwilling for (prolonged) hospitalization, (f) in patients unwilling for a urethral stent or catheter, and (g) in hypospadias cripples to avoid mobilization of distant tissues such as tunica vaginalis flap or a buccal mucosal graft for supplementing the UCF repair.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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