When to remove the urethral catheter after endoscopic realignment of traumatic disruption of the posterior urethra?

25 septembre 2017

Auteurs : H.M. El Darawany
Référence : Prog Urol, 2017, 11, 27, 594-599




 




Introduction


Endoscopic urethral realignment is a minimally invasive technique that was described for the early management of traumatic posterior urethral disruption [1, 2, 3]. In spite of its wide popularity, a high incidence of post-operative urethral stricture developed, sometimes exceeding 50% [2, 4, 5, 6, 7, 8]. The high incidence was also reported after surgical urethral realignment [9].


The Foley catheter is commonly removed 3-6weeks post-operatively when pericatheter retrograde urethrograms showed no evidence of extravasation [2, 3, 6, 7, 8, 10, 11]. In this study, endoscopic evidence of complete mucosal healing rather than pericatheter retrograde urethrography was the determining factor for selecting the optimal time of removal of the urethral catheter. The incidence of subsequent development of urethral stricture was assessed.


Patients and methods


This retrospective study comprised 21 adult males (12-43years old; mean=26.3years) who were presented by traumatic urethral rupture and managed by endoscopic urethral realignment during the period from October 2008 till January 2016. The procedure was aborted in 3/21 patients for failure to establish endoscopic urethral realignment. The remaining 18 patients were included in the study. The patients were admitted from the Emergency Room with pelvic fractures and complete disruption of the prostato-membranous urethra following road traffic accidents. Diagnosis was confirmed by retrograde urethrography.


Percutaneous suprapubic cystostomy was performed shortly after admission in all patients to relieve urine retention. Appropriate investigations were carried out to screen for possible associated injuries that were managed by the concerned medical teams. Endoscopic urethral realignment was performed under general anesthesia in 14 patients within 3days from the date of admission. There was a delay of 5-8days in 4 patients to control associated renal injury, liver injury and/or hemodynamic instability.


A flexible urethroscope was introduced along the distal urethra (retrograde flexible urethroscope) to visualize the proximal urethral end. If failed, identification of the proximal urethral segment was facilitated by injection of methylene blue in the bladder through the suprapubic catheter with attempt to follow the dye emerging from the proximal urethral end. Simultaneous use of an antegrade flexible cystoscope that was introduced through the suprapubic cystostomy tract was used if the proximal urethral end failed to be visualized directly or by the aid of methylene blue. The antegrade cystoscope was advanced to the proximal urethra. It was used for antegrade light illumination, injection of methylene blue or advancement of a guide wire to the pelvic cavity and trial to follow any of them by retrograde flexible urethroscope to visualize the proximal urethral end. Once the proximal segment was identified by the retrograde flexible urethroscope, a guide wire was advanced to the proximal urethra then to the bladder. The retrograde flexible urethroscope was then removed from the urethra and a Foley catheter (14Fr-18Fr) was advanced over that wire to the bladder and fixed. The antegrade flexible cystoscope used to confirm the position of the Foley catheter inside the bladder. After removal of antegrade flexible cystoscope, suprapubic catheter was inserted. The urethral catheter serves as a stent while the suprapubic catheter used for bladder drainage.


The endoscopic realignment was terminated when there was inability to visualize the proximal urethral end either directly by the retrograde flexible urethroscopy, or by simultaneous use of retrograde and antegrade flexible endoscopy with aid of methylene blue, guide wire or light emerging from the proximal urethral end.


Pericatheter retrograde urethrogram was performed in all patients 6week post-operatively. In the absence of contrast extravasation, the Foley catheter was removed followed by immediate flexible urethroscopy as an outpatient procedure to assess the mucosal healing at the level of the realignment gap between the 2 aligned urethral segments. If mucosal healing was incomplete, the Foley catheter was re-inserted in the bladder over a guide wire. Urethroscopy was repeated at 9 and 12weeks till mucosal healing was complete. The urethral Foley catheter was then removed. Follow-up uroflowmetry was done 12-36months post-operatively.


Results


None of the patients had any history of urological or sexual problems prior to urethral injury. They all had pelvic bone fractures and complete disruption of the posterior urethra at the time of presentation. According to Tile classification of fracture pelvis [12], 12 patients had Tile A stable pelvic fracture, 6 had Tile B vertically stable/rotationally unstable pelvic fracture, and 3 had Tile C rotationally and vertically unstable pelvic fracture. Endoscopic urethral realignment was successful in 18/21 patients. The 3 failures (all of them had Tile C rotationally and vertically unstable fracture pelvis), were caused by inability to identify the proximal disrupted urethra endoscopically and were later treated by perineal urethroplasty. They were excluded from the study.


The delay of endoscopic realignment of 5-8days in 4 patients who had Tile B rotationally unstable/vertically stable fracture pelvis did not jeopardize the post-operative results as they all had unremarkable outcomes. At the time of realignment, the proximal urethral end was identified by the retrograde flexible urethroscope in 2 patients without need for assisted antegrade guidance. Antegrade guidance using methylene blue was required in 3 patients, illumination in 5 and advancement of a guide wire in 8.


The operative time estimated, from insertion of the retrograde flexible urethroscope to fixation of urethral catheter, was 23 to 39mins (mean 30.9mins, median 31mins).


At 6weeks, pericatheter retrograde urethrogram showed no extravasation of contrast in any of the patients. The Foley catheter was removed and a flexible urethroscope was then easily advanced under vision along the entire urethra till the bladder. The realignment gap appeared completely surrounded by connective tissue around a patent lumen. None of the patients had complete mucosal healing. The mucosa covered 50-75% of the circumference of the realignment gap (Figure 1). The remaining non-epithelialized circumference was still covered by connective tissue. Those findings were based on the operator's subjective assessment. A Foley catheter was re-inserted and urethral stenting continued for another 3weeks.


Figure 1
Figure 1. 

Urethroscopy at 6weeks: a 3×4cm non-epithelialized area in the realignment gap lined by connective tissue (white arrows). The black arrow points to the prostatic urethra.




A second urethroscopy at 9weeks, after removal of Foley catheter, showed complete epithelialization in 15/18 patients (83%) with the mucosa covering the entire circumference of the realignment gap. 12/15 patients previously had Tile A stable fracture pelvis and 3/15 previously had Tile B vertically stable/rotationally unstable fracture pelvis. So, the urethral catheter was not re-inserted. In the 3/18 remaining patients (17%) who had Tile B fracture pelvis, 90-95% of the circumference of the realignment gap was covered by mucosa, leaving 5-10% still lined only by connective tissue without mucosa (Figure 2). In those 3 patients, Foley catheter drainage continued for 3 moreweeks till complete mucosal healing was later observed at week 12 by a 3rd urethroscopy.


Figure 2
Figure 2. 

Urethroscopy at 12weeks (same patient): most of the non-epithelialized area has been covered by mucosa leaving a 1×0.5cm area where the deeper connective tissue layer was still exposed (white arrows). The Foley catheter in this patient was removed at week 15 when epithelialization was complete. The black arrow points to the verumontanum and prostatic urethra.




All 18 patients were continent and voided satisfactorily after catheter removal 9-12weeks post-operatively. One patient (5.6%) in whom the Foley catheter kept for 12weeks developed symptomatic urethral stricture 5months after removal of catheter. The stricture was mild and was successfully treated by a single session of internal urethrotomy. Follow-up uroflowmetry done 12-36months post-operatively revealed a mean peak urinary flow rate of 15.8mL/s (range 12.7 to 18.3).


Discussion


Following complete disruption of the posterior urethra, the distal urethral segment remains fixed to the urogenital diaphragm while the proximal segment retracts back in the pelvic cavity. A wide non-aligned gap develops between both urethral segments [13]. The common current practice for management of post-traumatic complete disruption of the posterior urethra is suprapubic cystostomy only to be followed a few months later by surgical urethroplasty. Endoscopic urethral realignment has recently gained popularity as an alternative line of treatment. It reduced but did not abort the need for surgical urethroplasty [7].


When traumatic posterior urethral disruption is managed by suprapubic cystostomy only, the subsequent healing process produces a long obstructed fibrous band within that gap. Surgical urethroplasty performed at a later stage is often difficult and challenging. On the other hand, the gap between both realigned urethral segments after endoscopic urethral realignment is short. It is referred to in this study as the "realignment gap". It was estimated to vary from 1.5 to 4cm in length [14]. This gap also heals by granulation tissue formation and can end in stricture development.


The Foley catheter that is inserted in the urethra at the time of realignment serves 3 important functions. It achieves intra-operative approximation with realignment of both disrupted urethral ends, it maintains post-operative urine drainage and it acts as a stent during the post-operative healing period. Unlike open urethral realignment, endoscopic urethral realignment has no sutures taken at the time of realignment and there is no dissection of devitalized tissues at the site of the trauma.


Many studies in the literature are in favor of endoscopic urethral realignment as a minimally invasive procedure [7]. Even though it was followed by a high incidence of urethral stricture, not all patients complained of stricture and many remained symptom-free throughout the follow-up periods. Urethral stricture is expected to develop post-operatively considering that the realignment gap is eventually occluded by fibrous tissue during the course of the healing process [15]. In their studies on the canine urethra, McRoberts and Ragde reported that healing of the transected urethra was solely by granulation tissue [16]. In another study, Hardy reported presence of re-epithelialization together with granulation tissue during the process of healing [17]. Flexible urethroscopy in this study confirmed presence of epithelialization by mucosal creeping from both aligned urethral edges to cover the granulation tissue at realignment gap.


The stenting effect of the Foley catheter is crucial for proper mucosal healing of that gap. The current practice as shown in the literature is to keep the urethral stent (Foley catheter) in place till pericatheter retrograde urethrography reveals absence of contrast extravasation [2, 3, 6, 7, 8, 10, 11]. In these studies, contrast ceased to extravasate 6weeks post-operatively in pericatheter retrograde urethrogram. Based on these findings, we used to do retrograde pericatheter urethrogram 6weeks after endoscopic realignment that showed no extravasation in all patients.


In the absence of extravasation of contrast by pericatheter retrograde urethrogram 6weeks post-operatively, flexible urethroscopy showed that the gap between the 2 realigned ends, in spite of completely covered by connective tissue, the mucosal covering was incomplete with patchy areas of the realignment gap being covered by mucosa and other patches being uncovered. That is why, complete healing of urethral wall at the realignment gap by granulation and connective tissue without complete mucosal healing can prevent contrast extravasation in pericatho-urethrogram.


Tausch et al. considered healing by fibrosis inevitably results in occlusion of the urethral lumen [15]. However, there seems to be a correlation between the extent of mucosal healing and the degree of urethral lumen occlusion. Re-epithelialization can exert a hindering factor on the occlusive effect of the granulation tissue. The more is the epithelialization by prolonged stenting, the less is the risk of stricture progression. Based on that, periurethral fibrosis is inevitable process and early removal of the urethral stent before complete mucosal re-epithelialization carries the risk of connective tissue to creep toward the lumen through spaces that have not yet been covered by mucosa, while complete mucosal re-epithelialization of the realignment gap limits the occlusive effect of the fibrous tissue that can result in urethral strictures.


In 7 studies [2, 3, 6, 8, 9, 18, 19] where the urethral stent was removed based on the results of pericathogram, urethral stricture developed in 14 to 79% of cases (Table 1). In this study, when urethral stenting continued till mucosal healing was complete as proved by flexible urethroscopy at 9-12weeks post-operatively, symptomatic stricture development dropped to 5.6%.


In this study, Flexible urethroscopy was performed in all patients 6weeks after endoscopic urethral realignment, twice in 83% and 3 times in 17%. The frequent use of flexible urethroscopy in this study is not a disadvantage; it is a simple office procedure that is performed under local anaesthesia with no side effects. It offered great benefit for determination of the extent of urethral mucosal healing and the proper time of catheter removal. The subsequent significant reduction in the incidence of post-operative urethral stricture saved many patients from the need of repeated internal urethrotomy or surgical urethroplasty.


Other factor that affect the success of endoscopic urethral realignment and its outcome is the type of associated fracture pelvis. In this study, it was noticed that endoscopic urethral realignment of the traumatic rupture urethra was failed in patients with Tile C pelvic fracture. The failure may be due to wide displacement of the two disrupted urethral ends secondary to associated big pelvic haematoma. However, there was no difference between Tile A and Tile B pelvic fracture regarding the procedure itself or its outcome.


Limitations to this study included the small number of patients not allowing statistical analysis. This was attributed to the infrequent cases of posterior urethral disruption seen in each hospital. In addition, the 12-36month follow-up period was not long enough to predict complete clinical cure. However, the results seemed to be favorable.


Conclusions


Following endoscopic urethral realignment, complete coverage of the realignment gap by connective tissue always preceded complete coverage by mucosa. The stenting effect of the indwelling urethral catheter is important for both connective tissue and mucosal healing around a patent lumen. Complete mucosal healing seems to hinder the obstructive effect of peri-urethral fibrosis. The use of a flexible urethroscope is important to observe the progress of mucosal healing and to determine the optimal time for removal of the Foley catheter after endoscopic urethral realignment.


Disclosure of interest


The author declares that he has no competing interest.




Table 1 - Incidence of stricture in relation to duration of post-operative urethral stenting by the Foley catheter.
Authors  Realignment  # of patients  Post op. catheterization (weeks)  Stricture (%) 
Elliott and Barrett, 1997 [9 Surgical  53  2-10  66 
Moudouni et al., 2001 [2 Endoscopic  29  4-6  41 
Mouraviev et al., 2005 [18 Endoscopic  57  4-6  49 
Hadjizacharia et al., 2008 [3 Endoscopic  14  3-6  14 
Sofer et al., 2010 [6 Endoscopic  11  45 
Leddy et al., 2012 [19 Endoscopic  19  2-12  79 
Johnsen et al., 2015 [8 Endoscopic  27  3-27  63 
This study  Endoscopic  18  9-12  5.6 




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