Keywords

1 Rectourethral Fistula

Rectourethral fistula (RUF) is a connection between the lower urinary tract and the distal part of the rectum. It was first described by Jones in 1858, although an earlier reference to a colovesical fistula is attributed to Rufus of Ephesus in 200 AD [1].

1.1 Incidence and Etiology

RUFs can be congenital or acquired. The first ones, usually related to imperforate anus, represent a small subset of this pathology and are managed by pediatric surgeons. Most of acquired RUFs are iatrogenic, resulting from prostate/bowel surgery or ablative treatments complications [1]; less commonly, fistulae can be a consequence of a trauma [2], Fournier’ gangrene [3], or Crohn’s disease [4].

The vast majority of RUFs are related to prostate cancer (PCa) treatment, and a 0.53–9% fistulization rate was observed after radical prostatectomy (RP) [5, 6], 0–6% after external beam radiotherapy (EBRT) [7], 0.4–8.8% after brachytherapy (BT) [8, 9], and 0.4–3% after cryotherapy and high-intensity focused ultrasound [10, 11]. Interestingly, while in the 1990s most of RUFs resulted from complications of prostate surgery, to date up to 52% of patients with a fistula has received radiation [12], often as a second-line treatment for biochemical recurrence. In contrast to primary treatment, in fact, salvage EBRT/BT could increase RUF incidence rate from 0.6 to 3% [13].

Considering that surgery still represents the most common treatment option in patients with a resectable tumor, most of the observed RUFs occur after prostatectomy and are often secondary to an unrecognized rectal injury (RI) during the operation [1]. According to a recent population-based study on 614,294 patients who underwent RP, perforation occurred in 2900 cases (0.5%) with a 26% decline from 2003–2006 to 2009–2012 (p < 0.01). Multivariable analysis identified concurrent benign prostatic hyperplasia (OR, 2.33; 95% CI, 1.16–4.69; p 0.02) and metastatic cancer (OR, 2.31; 95% CI, 1.53–3.5; p < 0.01) as predictors of RI, while robotic approach (OR, 0.38; 95% CI, 0.29–0.50; p < 0.01), high-volume hospital (OR, 0.58; 95% CI, 0.46–0.72; p < 0.01), and obesity (OR, 0.56; 95%CI, 0.34–0.93; p 0.02) reduced the risk [14]. Post-RP RUFs are commonly found in close proximity of the urethrovesical anastomosis: experts in the field observed that most of these fistulae are not actually located through the anastomosis but rather at the “tennis racket handle” between the ureters, where a foreign body (usually a hemostatic clip) migrated causing fibrosis and fistulization [13]. Prior radiation and/or ablative therapies increase the risk of fistula, in a dose-dependent manner, and decrease the likelihood of its spontaneous closure as a result of ischemia and fibrosis they induced [12]. Moreover, these therapies also complicate the repair surgery due to the lack of laxity and the avascularity of the surrounding tissues [7].

1.2 Diagnosis and Evaluation

RUF diagnosis is clinical, and an appropriate medical interview is imperative. Pneumaturia is the most common sign (67–85%) followed by urine leakage through the rectum during micturition (40–100%) and fecaluria (39–65%), which is also the most specific. Other common findings are recurrent urinary tract infections (73 %), abdominal pain (22 %), and dysuria (14.6%) [15]. An acute presentation (0–3 weeks from hospital discharge) is common in post-RP cases, while a delayed onset of symptoms (>14 weeks from treatment) is more common in irradiated patients.

Digital rectal examination allows identification of the fistula and direct size estimation: usually post-surgical RUFs are small and barely palpable, while those post-EBRT are larger.

Radiologic evaluation (CT scan, magnetic resonance imaging, voiding cystourethrogram, retrograde urethrography) and endoscopic procedures (cystoscopy, proctoscopy) help in delineating the anatomy and selecting the appropriate treatment strategies (Fig. 1).

Fig. 1
figure 1

Suggested algorithm to guide treatment selection in patients with RUFs

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1.3 Classification

The use of a standardized classification for RUFs would allow both selection of the optimal treatment for each patient and comparison of outcomes among different series. An attempt was done by Prof. Anthony Mundy, who distinguished between direct and cavitating fistulae merely on the basis of their morphological features [13]. Hanna et al. suggested to classify RUFs according to their distance from the rectal sphincter (<2 cm vs. >2 cm) as distal ones could better benefit from a transperineal approach rather that trans-sphincteric surgery. More clinically relevant was the classification proposed by Montorsi et al. (Table 1) who differentiated RUFs on the basis of their size and etiology. In fact, the diameter of the fistulae causes symptom burden (as smaller ones usually present with pneumaturia and are not associated with fecaluria and recurrent UTI) [7], while the vascularization of the surrounding tissues, which primarily depends on their degree of irradiation, affects chances to heal (99% success rate after RUFs repair when no prior non-surgical treatment has been administered vs. 87% for fistulas caused by treatment with energy ablation as either primary or adjuvant) [16].

Table 1 Classification of rectourethral fistulas after primary treatment of prostate cancer based on size and etiology
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1.4 Management

Although over 40 techniques have been described which all share the basic principles for urinary fistula surgical repair (Table 2), there is no consensus on the optimal approach, whereby the vast majority of currently available studies consist of single-institution experiences, small case series, or case reports. Moreover, no comparative series with long-term follow-up are currently available to identify the best approach for patients with RUFs after PCa treatment.

Table 2 Common principles of urinary fistulae surgical repair
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1.4.1 Conservative Management

It has been suggested that a RUF might close spontaneously, but it only occurred within 6 weeks from PCa surgery, before the track had epithelialized [17]. Otherwise, there is no report of an established fistula closing spontaneously and permanently, and no suggestion at all that a post-irradiation one would do so [19,20,20].

In the early post-RP period, in order to control symptoms, an indwelling catheter and a colostomy may be necessary, especially in patients with extravasation of urine and fecal leakage: as the flow gradient is from the urinary tract to the rectum, the catheter is more likely to be helpful than fecal diversion [13]. As a matter of fact, most patients with RUF, whether post-surgical or post-irradiation, receive a colostomy either in the hope that this might promote a spontaneous healing or otherwise to “prepare” the subsequent repair. The decision to perform a temporary colostomy/ileostomy is not standardized, and some groups base this decision on clinical facts: for patients only suffering from pneumaturia or urine leakage through the anus, resolution through a low-residue diet is first attempted, while those experiencing fecaluria or sepsis are considered for colostomy straightaway [13, 17, 18].

In recent years, new approaches using sealant or fibrin glue [21] have emerged. In 2001, Bardari et al. reported the use of cyanoacrylate glue for the treatment of a post-RP fistula [22]. Similarly, Bhandari et al. further resorted to the same approach to heal a neobladder fistula after radical cystoprostatectomy [23]. These reports of favorable outcomes are however anecdotal, and further cases are necessary to validate those results.

1.4.2 Transanal Approaches

1.4.2.1 The Latzko Procedure

First conceived in 1914 for the treatment of vesicovaginal or enterovaginal fistulae, the transanal Latzko technique was used by Noldus et al. in 1997 to repair RUFs occurred after radical retropubic prostatectomy [24]. Although it provides poor visibility and limited instruments maneuverability, it is simple, does not require fistulous tract excision, and may be repeated as many times as necessary. It is indicated for small proximal fistulae.

The patient is placed in the lithotomy position, and cystoscopy is performed to localize the fistula. A 5F ureteral catheter is placed through the fistula endoscopically, and the area of the fistula at the site of the rectum is exposed with an anal retractor. Trendelenburg position may improve the visualization of the anterior rectal wall. A solution containing adrenalin (1:20,000) is injected around the fistulous opening to facilitate dissection and decrease bleeding. A circular area of rectal mucosa is incised for 1.0–1.5 cm from the fistulous opening. The rectal mucosa is denuded in four quadrants (Fig. 2a). No rectal mucosa is allowed to remain between the edges of the incision and the fistulous opening. The ureteral catheter is removed, and the fistula is closed with two layers of separate side-by-side 3-0 absorbable sutures (Fig. 2b, c). The margins of the rectal wound are similarly closed thereafter. A transurethral Foley catheter is placed in the bladder.

Fig. 2
figure 2

A circular area of rectal mucosa is incised for 1.0–1.5 cm from the fistulous opening, and the rectal mucosa is denuded in four quadrants (a). The ureteral catheter is removed, and the fistula is closed with two layers of separate side-by-side 3-0 absorbable sutures (b). The margins of the rectal wound are similarly closed thereafter (c)

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1.4.2.2 Endorectal Wall Advancement Flap

The use of transanal flaps in the management of fistulas involving the rectum was first published by Jones et al. in 1987 [25] and further popularized by Dreznik for the treatment of RUFs [26]. The technique is simple and safe, does not require a colostomy, and avoids any division of the sphincteric mechanism. It is indicated for proximal fistulae.

The operation is performed in the prone jack-knife position with the table flexed at the level of the hip joint. A self-retaining Parks’ self-retaining anal retractor is inserted, to expose the anterior rectal wall. A local injection of diluted adrenalin (1:20,000) may decrease bleeding and ease dissection. The fistulous tract is excised to leave a transverse defect of 1–2 cm in the anterior rectal wall. A longitudinal incision is made in the rectum from each lateral edge of the defect for 3–4 cm proximally, and an intersphincteric sharp dissection is performed so that a U-shaped rectal flap can be obtained (Fig. 3a). The defect in the urethra is closed using 3-0 absorbable interrupted sutures (Fig. 3b). The rectal flap is then advanced over the fistula and sutured to the rectal wall with interrupted 2-0 braided sutures ensuring the absence of tension (Fig. 3c). Three weeks later, the urinary catheter is removed.

Fig. 3
figure 3

Approximately 1 cm far from the fistulous tract, a U-shaped incision of the anterior rectal wall is performed, and an intersphincteric sharp dissection is carried on until a flap is obtained (a). The defect at the level of the urinary tract is closed using 3-0 absorbable interrupted sutures (b). The fistulous tract is resected from the rectal flap which is then advanced over the fistula and sutured to the rectal wall with interrupted 2-0 braided sutures (c)

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To overcome the inherent limitations of poor visibility and limited instrument maneuverability that characterize transanal approaches, the resort to endoscopic microsurgery (TEM-TAMIS) has also been proposed, with different treatments of the fistulous tract, urethral orifice, and rectal opening: experiences in this field are limited to small series and case reports [28,29,30,30].

1.4.3 Transperineal Repair

First described by H.H. Young in 1926, the transperineal approach for the treatment of RUFs was popularized by Goodwin in the 1950s. The technique is popular among urologists as they are familiar with this surgical route to the prostate gland. It provides a good exposure of the fistula and allows for tissue interposition between the rectum and the urinary tract. Its success rate ranges between 78 and 100%, with one or several interventions [31, 32].

The patient is placed in a lithotomy position, and a transurethral catheter is inserted. A wide inverted-U-shaped perineal incision is made outside the anus (2 cm far from its verge) and inside the ischial tuberosities (Fig. 4a). The subcutaneous tissue is divided, and a fingertip is used to bluntly develop the two ischiorectal fossae. The central tendon of the perineum is transected, and the anterior rectal wall exposed. The scarring between the urethra, the bladder, and the anterior rectal wall is dissected sharply until the fistulous tract is identified and completely excised. The preoperative endoscopic placement of a Pollack catheter through the fistula may help in identifying it during surgery. Both the urethral and rectal orifices are released and sutured in two planes, forming a right angle between them (Fig. 4b). Lane first proposed implanting a buccal mucosa patch to close wide fistulas, ensuring a healthy and epithelized tissue [12]. Adequate separation of the urinary tract from the rectum by the interposition of either the levator ani muscle or other transposition flaps [33] (with the gracilis [31], dartos [34], and gluteal muscles [35]) is advised, especially in the setting of post-radiation fibrosis, large/multiple fistulas, or other risk factors for failure of primary repair [33] (Fig. 1). A perineal drainage is left in place. The bladder catheter should not be removed before 14–60 days. To restore intestinal continuity, a mean accepted period is 3 months.

Fig. 4
figure 4

With the patient in a lithotomy position, a wide inverted-U-shaped perineal incision is made outside the anus and inside the ischial tuberosities (a). With blunt dissection, the two ischiorectal fossae are developed. The central tendon of the perineum is transected, and the anterior rectal wall exposed. The fistulous tract is carefully identified and excised: the urethral and rectal orifices are released and sutured in two planes, forming a right angle between them (b)

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In 1979, Ryan first used the gracilis muscle for the treatment of three urinary fistulae: since then the technique has been replicated by many authors with high healing rates (83–95%), although the published series are very limited [31, 32]. Spiegel et al. also proposed an endoscopic approach to harvest the flap [36].

With the patient in a lithotomy position, an 8-cm longitudinal incision is made on the medial thigh, starting at the estimated location of the vascular pedicle (which can be identified on the anterior boarder of the muscle with the help of Doppler). A small counter incision is made distally over the site of insertion of the muscle just below the medial condyle of the tibia. The muscle is lifted off the belly of the underlying adductor magnus with cautery and blunt dissection. The distal tendinous insertion is transected, and the muscle is pulled through the proximal incision. Then, a tunnel is made between the thigh and the perineal incision, and the muscle is rotated 180° and passed through the tunnel where it is secured in place between the two suture lines of the fistula repair.

Based on the wide experience of the use of buccal mucosa graft (BMG) for substitution urethroplasties, in 2006 Lane et al. proposed to resort to this free graft to close wide urinary fistulae, provided a healthy bed was available.

1.4.4 Transanorectal Sphincter-Splitting Repair (York Mason Procedure)

First described by F.R. Kilpatrick and A. York Mason in 1969 [37] with a parasacral-coccygeal trans-sphincteric access, the technique was further modified by the latter in 1970 [38]. With small variations this approach is recommended by numerous authors (especially general surgeons) because of its ease, accessibility, satisfactory outcomes, and lack of complications. Success rate of this procedure exceeds 85%; anal continence is rarely affected [39].

Preoperatively, an 18Ch bladder catheter is inserted. The patient is then placed in the prone jack-knife position, and the buttocks are separated. An oblique incision from the left side of the sacrum and coccyx up to the posterior anal margin is performed, sectioning the entire sphincter complex (external sphincter, internal sphincter, and puborectalis/levator), leaving them marked with dots for an easier later repair. Then, an opening is made on the posterior rectal wall, which enables a perfect view of the anterior rectal aspect with its fistulous orifice. The entire fistulous tract is resected, including the rectal wall, the urethral wall, and the surrounding tissues, thus enabling the correct suture of healthy tissues. There is no consensus regarding the need for urethral orifice closure (unless it is achieved in a tension-free manner and on healthy tissue), while the rectal orifice should be closed in two planes (submucosa and muscle in the first, everted mucosa in the second) both with absorbable stitches (Fig. 5). The urethral and rectal sutures should not overlap: occasionally, a rectal advancement flap is required [2]. The final step is the closure of the posterior rectal wall and sphincter and subcutaneous and skin reconstruction, leaving a suction drainage at the subcutaneous level for 24–48 h. The bladder catheter should remain placed for 6–8 weeks. With respect to the need of a fecal diversion, even though most authors recommend it, the possibility of omitting it is also accepted in cases of small fistulae, without extensive fibrosis, and in the absence of uncontrolled systemic infection, sepsis, or abscess [39]. If a colostomy is made, the closure will take place between 2 and 3 months after the procedure. Prior to restoring the intestinal continuity, the complete closure of the fistula should be confirmed by cystoscopy, retrograde cystourethrogram, rectoscopy, and even opaque enema, to confirm there is no communication.

Fig. 5
figure 5

With the patient in a prone jack-knife position, an oblique incision from the left side of the sacrum and coccyx up to the posterior anal margin is performed, sectioning the entire sphincter complex and the posterior rectal wall. With the anterior rectal wall properly exposed, the fistulous tract is resected, and the urethral orifice is closed in a tension-free manner, on a healthy tissue. Then the rectal orifice is also closed, in two layers, with absorbable stitches

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1.4.5 Transabdominal

This has been for decades the less commonly used approach. Although it provides access to both the omentum and peritoneum so that pedunculated and free flap for interposition could be obtained, open surgery via a violated abdominal cavity implies greater morbidity and, more importantly, poor exposure of the deep pelvis. In recent years, a renewed interest toward this route was observed thanks to minimally invasive techniques. Using a laparoscopic approach, Sotelo et al. treated three patients with simple RUF [40], while Bollens successfully treated a 5-cm-wide recto-vesical fistula [41]. Similarly, other authors recently shared their experiences with the use of a robot-assisted approach in this field [42, 43].

1.4.6 Urinary Diversion

In certain extremely complex cases, a permanent urinary and/or fecal diversion and even pelvic exenteration may be needed [7, 12, 18].

2 Lymphocele

The word “lymph” derives from the Roman deity of fresh water, Lympha. First termed as lymphocyst by Mori in 1955 [44], lymphocele (LY) is a collection of lymphatic fluid surrounded by a fibrotic wall that lacks epithelial lining.

2.1 Incidence and Etiology

The pathophysiology of LY formation is largely speculative: during lymph node dissection (LND), leaking fluid from unsealed lymph channels may collect in the pelvis being further walled off from the peritoneal cavity, confined into a pseudocyst with a hard fibrous capsule. If lymphadenectomy is not performed, the risk of LYs is negligible [45].

Their true incidence has not been defined yet, as most are asymptomatic. Orvieto et al. routinely performed postoperative CT scans at 6 and 12 weeks after surgery in 76 men that underwent robot-assisted radical prostatectomy (RARP) with pelvic LND (PNLD): 51% of patients developed LYs, and 15% of which were symptomatic [46].

Various authors investigated possible risk factors for LY formation, but results were inconclusive. Capitanio et al. highlighted that lymph node yield during PLND was an independent predictor, and, for every node removed additional to a threshold of 20, the risk increased by 5% [47]. Conversely, Khoder et al. found no correlation between the number of excised lymph nodes and the rate of LY [48]. Interestingly, Liss [45] provided evidence that also the actual extent of PLND does not predict the risk of LY formation, and, in a longitudinal study on patients that underwent RARP with extended (n = 202) or standard PLND (n = 204), no differences in the rate of radiologic (22% vs. 23%) and symptomatic LYs (3% vs. 2.5%) were observed [49].

Another potential risk factor for LY formation is performing an extraperitoneal vs. a transperitoneal prostatectomy. In fact, it is thought that the latter approach promotes reabsorption of the lymphatic fluid by the peritoneum. So far, there have been no prospective randomized trials attempting to verify this hypothesis, and few supporting evidences arise from retrospective analyses [50, 51]. Interestingly, Stolzenburg et al. observed a significant reduction in incidence of LY following extraperitoneal radical prostatectomy (RP) and PLND by bilateral peritoneal fenestration, compared to conventional technique (radiologic LYs, 6% vs. 32%; p < 0.001; symptomatic LYs, 0% vs. 14%; p < 0.001) [52].

Since lymph also contains coagulative factors as plasma, the use of perioperative heparin (to prevent deep vein thrombosis [DVT] and pulmonary embolism [PE]) could prolong the closure of the afferent lymphatic channels injured during LND. However, this theoretical correlation is still controversial: Tomic et al. observed a sevenfold greater incidence of LY formation in patients that received heparin [53], while other studies failed to prove the same [54]. Overall, the potential for life-threatening thromboembolic events should overweight the possible increased risk of LYs with perioperative low-molecular-weight heparin.

2.2 Clinical Spectrum

Although most LYs occur asymptomatically, up to 15% can become symptomatic [46] because of superinfection (causing fever and/or sepsis) or compression on adjacent structures (potentially resulting in abdominal discomfort, venous drainage impairment, lower limb edema, DVT/PE). While thromboembolic events after RARP with PLND are rare (<1%), LY infection occurs in a non-negligible percentage of cases (3%), and Gram-positive cocci represent the most common (73%) causative organisms [55], probably coming from skin flora. Although codified antibiotic regimens are not available yet, patients with infected LYs should be treated for about 4–6 weeks, similar to abdominal abscess, and Gram-positive coverage is a reasonable empiric therapy choice; in case of sepsis, anti-Pseudomonas and anti-anaerobes agents such as piperacillin/tazobactam or cefepime plus metronidazole should be considered [55].

2.3 Management

2.3.1 Potential Preventative Strategies

Various strategies to prevent LY formation have been explored over the years. Leaving a drain longer to divert lymphorrhea sounds intuitive; however, a randomized study demonstrated no statistically significant difference in the incidence of LY (asymptomatic and symptomatic) between patients that had their drain in place for 1 day, 7 days, or no drainage at all [51]. These results were further confirmed by Chenam et al., in a robotic series [56]. Similarly, Gotto et al. found that the number of pelvic drains does not predict the risk of symptomatic LYs after RP with LND [57]. Probably, pelvic drainage adds little value to prevent this complication, and most of the studies failed to prove its role as tubes were removed quite early, considering that most lymph collections are diagnosed 3 weeks after surgery [58].

It is commonly believed that a meticulous ligation of the afferent lymphatic channels minimizes lymphorrhea. Few authors identified monopolar energy as the worst sealing technique, followed by bipolar and ultrasonic energy, while clips appeared as the most effective option [46, 59]. On the contrary, a Swiss prospective randomized trial failed to prove any difference between the use of clips and electrical coagulation during RARP with PLND in terms of overall (47% vs. 48%; p = 0.9) and symptomatic (5% vs. 4%; p = 0.7) LY rates [60]. Indeed, the major limitation of that study was the application of titanium clips only at the femoral canal; as such, Devis and colleagues reported an <1% incidence of LY after extensive clipping during PLND [61].

Fibrant and hemostatic sealants (such as Floseal [62], Tachosil [63], Arista AH [64], Vivostat [65]) have been proposed as adjuvant measures to mitigate lymphorrhea, but definitive evidence in their favor still lacks.

The transperitoneal approach to prostatectomy has been associated to a reduced risk of LYs [50, 51]. In case the extraperitoneal route is chosen instead, making large fenestration in the peritoneum at the end of the procedure may prevent lymph from collecting in a closed space [52].

In 2012, at the Lahey Institute of Urology, the peritoneal interposition flap was conceived: after transperitoneal RP with PLND, the visceral serosa covering the bladder is folded on its lateral aspects and sutured there to prevent the organ from adhering to and walling off the LND bed while allowing continuous egress of lymphatic fluid into the peritoneal cavity. Its efficacy was proved in a non-randomized study, where the LY rate in the Lahey-stitch group was 0% vs. 11.6% in the control group [66]. This technique was slightly modified by Dal Moro [67] and Stolzemburg [68], who provided evidence that peritoneum reconfigurations (Fig. 6) significantly reduce the risk of pelvic lymph collections. Results from randomized controlled studies (NCT03567525) are awaited.

Fig. 6
figure 6

The concept of peritoneal advancement flap requires that the visceral serosa covering the bladder is exposed to the iliac vessels and obturator fossae. To achieve this, the peritoneum-lined aspects of the taken-down bladder (a) are sutured to the anterior and lateral pelvic sidewalls (b)

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2.3.2 Treatment Options

Once considered the treatment of choice, surgical evacuation with fenestration or marsupialization (either via laparotomy or laparoscopy) is nowadays outdone by a wide range of radiologic interventions. At present, the gold standard treatment option is percutaneous catheter drainage; sclerotherapy with chemical agents can improve its efficacy by triggering a chemical reaction that obliterates the lymph vessels and cavity preventing further leakage. As little data exist, consensus is lacking on the best sclerosing agent, its dosage, and the length of administration. Ethanol, povidone-iodine, and tetracyclines are frequently used, as these are affordable, easily available and generally well tolerated.

Other LY treatment options include percutaneous fine needle aspiration and embolization during lymphangiography (in which N-butyl cyanoacrylate glue is directly injected into lymph nodes or lymph vessels to treat downstream leaks). According to a recent systematic review, lymph aspiration provided the lowest success rate (0.341; 95% CI, 0.185−0.542), followed by percutaneous catheter placement (0.612; 95% CI, 0.490−0.722). When sclerotherapy was added, efficacy increased up to 0.890 (95% CI, 0.781−0.948) for delayed addition and 0.872 (95% CI, 0.710−0.949) for instantaneous addition. The embolization group showed the highest success rate (0.922; 95% CI, 0.731−0.981). Complication rate was the highest after percutaneous catheter drainage, while lymph node embolization appeared as the safest approach. However, further prospective research with correction for predisposing and aggravating factors, and focus on differentiation between primary and secondary treatments, is required to ultimately determine the optimal treatment modality for symptomatic postoperative pelvic LYs [69].

3 Vesico-urethral Anastomotic Stenosis

Bladder neck contracture (BNC), also termed as vesico-urethral anastomotic stenosis (VUAS), is a potential complication after radical prostatectomy (RP) which presents as scar tissue obstructing the bladder outlet.

3.1 Incidence and Etiology

Its true incidence is unknown as there are no available studies routinely assessing urethral patency after surgery: thus, only patients complaining for postoperative voiding symptoms have been eventually diagnosed with BNC. Interestingly, the rate has declined over the years as it was 2.6–7.5% after open RP (ORP) vs. 0–2.1% in the robot-assisted era [70, 71].

The underlying molecular mechanisms are poorly understood: in the physiological wound healing process, fibrogenesis is tightly regulated and leads to successful tissue repair. If the fragile balance between cytokines, growth factors, mesenchymal cells, and extracellular matrix is deregulated, excessive scar tissue formation may happen. It is thought that an association between peripheral vascular disease and BNC exists: in fact, current cigarette smoking is its strongest independent predictor, followed by coronary artery disease, hypertension, and diabetes [72]. Similarly, men undergoing adjuvant radiotherapy showed a twofold increased risk of VUAS [73] compared to prostatectomy alone. The type of suture used for the anastomosis and the duration of catheterization do not affect contracture incidence, while an increased number of sutures/takes does [70, 72].

3.2 Clinical Presentation and Diagnosis

Most symptoms occur within 6–12 months from RP: obstructed urine flow, recurrent infections, retention, and occasionally urinary incontinence are strongly suggestive of BNC [74].

According to international guidelines, the workup should start with a medical interview, and baseline continence status should be assessed. Urinalysis with culture should be included to rule out other etiologies that may mimic stenosis; prostate-specific antigen test should be performed to exclude cancer recurrence. Uroflowmetry and post-void residual urine measurement could be considered to objectify symptoms. Cystoscopy is helpful to confirm clinical suspicion of BNC, and it is crucial to identify stenotic involvement of the external sphincter. Also retrograde urography with voiding cystogram could provide valuable information about the status of anterior and posterior urethra [75]: it is usually reserved for cases in which complete cystourethroscopy cannot be performed for multiple strictures, complete urethral obliteration, and patients unwilling to undergo a procedure in an ambulatory setting [76].

3.3 Management

3.3.1 Dilation

Interruption of the stenotic bladder neck is the central premise of endourologic procedures for VUAS. However, according to SIU/ICUD consultation on urethral strictures, dilation is indicated in early postoperative stenoses (<6 months) [76]. The endoscopic placement of a guidewire and the use of co-axial sounds or balloon dilators will reduce the risk of false passage creation or disruption of a fresh anastomosis. Up to 59% success rate has been reported for these approaches; very few evidences, however, support favorable long-term outcomes [77, 78].

3.3.2 Direct Vision Internal Urethrotomy (DVIU)

For strictures that fail initial dilation or occur >6 weeks after RP, a low-energy urethrotomy is recommended [76, 79]. There is low-level evidence supporting a certain superiority of holmium laser over cold-knife incision [80]. The original technique was proposed by Dalkin in 1996: two deep incisions at 4 and 8 o’clock positions are performed with a cold-knife urethrotome, down to the bleeding tissue, from the proximal area of the contracture to its distal extent. Pin-point coagulation is only used in case of major arterial bleeding. At the end of the procedure, a 20–22 Ch urethral catheter is left in place for 72 h [81]. A triradial technique was further proposed by Vanni et al. [82]: however, aggressive incisions at 6 and 12 o’clock positions are strongly discouraged because of the risk of rectal injury and urosymphyseal fistulation, respectively [83]. DVIU for obliterative VUAS is not advised because of the limited success rate and the considerable risk of perforation [84]. De novo urinary incontinence was observed in 0–10% of cases; interestingly, a non-negligible (20–52%) share of patients with pre-existing leakage experienced improvements after surgery [85, 86]. Patency after the first urethrotomy ranges between 25 and 80% [85, 86]; repetitive endoluminal treatments can be attempted to stabilize recalcitrant strictures [79], but ultimately 6–10% of patients will require permanent urinary diversion [87]. Intralesional injections of different drugs were also attempted to treat recurrent BNCs: after corticosteroid injections the success rate was 50–100% [88, 89] and 58–79% after mitomycin C [90, 91]. With this regard, however, Redshaw et al. also reported osteitis pubis, bladder neck necrosis, and rectourethral fistula in few patients which had the latter drug injected [90].

The role of intermittent self-catheterization in reducing recurrence after surgery has not been established yet: we recommend self-hydropneumatic dilations for a couple of weeks after DVIU, which is achieved by means of intermittent compressions of penile urethra during micturition.

3.3.3 Transurethral Electrosurgical Incision/Resection (TUR)

It has been used when dilation and DVIU have failed. The greater risk of incontinence (14–50%) should be considered against the likelihood of long-term urethral patency (40%) [84, 89, 92].

3.3.4 ReDo Vesico-urethral Anastomosis and Y-V Plasty

All endoscopic therapies inherit the risk of recurrence: in these patients further attempts should be avoided, and surgical reconstruction of the vesico-urethral anastomosis (VUA) discussed. Temporary suprapubic cystostomy drainage will allow planning for reconstruction. Patient age, previous surgery or radiation, cancer stage, and life expectancy must be assessed before intervention. The primary goal should be urethral patency, with many men requiring an artificial urinary sphincter (after 3–6 months, at least) [76, 79].

Different techniques (abdominal retropubic, transperineal, combined) and approaches (open [93, 94], robotic [96,97,97]) have been proposed. With this regard, the introduction of the SP-DaVinci platform may offer significant advantages allowing the surgeon to operate in extremely narrow spaces [96].

In patients with adequate bladder function and in the absence of periurethral pathology (necrosis, calcifications, fistulas), the retropubic/abdominal route should be preferred [76, 79]: if an extensive urethral mobilization can be avoided, preservation of continence is possible. In these cases, the bladder neck is approached anteriorly by developing the space of Retzius. The dissection is then carried inferiorly, beneath the pubic symphysis, to the area of the bladder neck. At this point, either a urethral catheter or flexible cystoscope may be placed to identify the location and distal extent of stenosis. The bladder can be opened anteriorly at the bladder neck to help localize the proximal extent of the scar, which is excised completely using electrocautery and sharp dissection. Once the bladder neck is circumferentially freed, the VUA is re-sewn. Alternatively Y-V plasty of the bladder neck can be performed: this avoids dissection of the stenotic urethra posteriorly and any potential rectal complications. A longitudinal incision through the anterior aspect of the scar is performed, and then an inverted-V incision is made on the anterior aspect of the bladder wall, at the level of the bladder neck. The apex of the V-shaped bladder flap is advanced into the distal aspect of the scar incision (Fig. 7). Patency rates vary between 83 and 100%, with 14–45 months of follow-up. De novo incontinence rate ranges from 0 to 14% [95,96,97,97].

Fig. 7
figure 7

Y-V plasty of the bladder neck. A longitudinal section through the anterior aspect of the scar is performed, together with an inverted-V incision of the bladder neck (a). The apex a of the advancement flap is then sutured to the most caudal point a′ of the incised scar (b)

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The transperineal approach inherits the advantages of operating in an unspoiled surgical field and allows for an easier mobilization of the urethra; incontinence, however, is unavoidable. The patient is placed in an exaggerate lithotomy position. A transperineal inverted-U-shaped incision is performed, and the urethra is dissected under digital rectal examination. A complete exposition of the anastomotic area is obtained, and the scar is excised until healthy tissue is reached. Wide mobilization of both the urethra and bladder should be obtained to guarantee a tension-free anastomosis. The urethra is spatulated dorsally, and the reanastomosis is sutured under direct vision control [93]. To increase visualization of anatomical structures, the use of a robotic camera has been recently proposed [98]. Patency rate up to 90% was reported [93, 98].

3.3.5 Stents

Several semi-/permanent metallic stents have been used in the setting of VUAS [99, 100]. Their use is currently discouraged by international guidelines [79] because of their limited efficacy and challenges with migration, tissue regrowth, or intrusion.

4 Well Leg Compartment Syndrome

Compartment syndrome is an uncommon complication of robot-assisted radical prostatectomy due to the increased pressure in the muscles of the lower extremities which leads to hypoperfusion of the tissues and necrosis.

4.1 Incidence and Etiology

Compartment syndrome is a rare complication after robot-assisted radical prostatectomy (RARP). The underlying cause of compartment syndrome is the increase in pressure in the muscle compartments surrounded by inelastic fascia when swelling or edema occurs, leading to an eventual increase in pressure in the compartment above perfusion pressure, leading to disruption of oxygenated blood flow and subsequent tissue necrosis [101]. Outcomes can be devastating and include loss of motor function, foot drop, permanent disability and restriction of mobility, lower limb amputation, renal failure from rhabdomyolysis, and death.

It is an uncommon condition in RARP, with an incidence of 0.29%, but that equates to three cases per thousand [102], so it is possible that most moderate- to high-volume surgeons may come across it once in their career, and the potential adverse outcomes are so severe that it must be taken very seriously as a condition. Lower limb compartment syndrome (LLCS) is often related to the use of the lithotomy position, with pressure being put on the calf muscles by the weight of the leg being suspended in stirrups of various designs. The use of Trendelenburg positioning can also contribute to LLCS in the setting of RARP [101]. Predisposing factors [102] include:

  1. 1.

    Extended time in lithotomy. It is traditionally felt that lithotomy duration of over 4 h increases the risk of LLCS, but it can occur in cases that last less than an hour.

  2. 2.

    Blood loss/hypovolemia

  3. 3.

    Hypotension

  4. 4.

    Obesity

  5. 5.

    Muscular, tight calves

  6. 6.

    Smoking

  7. 7.

    Peripheral vascular disease

  8. 8.

    Compression of iliac vessels such as during lymphadenectomy

The underlying pathophysiology that occurs is a rise of the internal compartment pressure to above 30 mmHg, although it can occur at lower pressures. The normal pressure is 0–10 mmHg. A rise in pressure causes a rise in compartmental pressure, leading to venous occlusion causing a rise in intracompartmental pressure to above mean arterial pressure with subsequent ischemia, as mentioned [102].

4.2 Clinical Presentation

LLCS usually manifests itself in the first few hours after injury but may present later. Pain is usually the first major complaint, with the pain being out of proportion to the injury. Pain is usually significantly increased on passive stretching. The tissue may also feel tense and “woody.” The traditional conglomeration of symptoms is described under the “the five Ps,” those being pain, pulselessness, paresthesia, pallor, and paralysis [101]. However, these may be late signs, and pain should be considered a cardinal sign, although this may be confused with the pain from deep vein thrombosis and may be masked by epidural analgesia use. There may paresthesia or loss of sensation in the first interdigital web space in the foot. The diagnosis is a clinical one, but measurement of intracompartmental pressures is a useful adjunct. This can be done by using either a transducer-tipped catheter or by a conventional fluid-filled system. There is no universal agreement on the precise intracompartmental pressure at which intervention should be considered. The decision to operate should be made in conjunction with clinical findings although a value of >30 mmHg usually shows that surgical decompression is needed. Alternatively, one can use the perfusion pressure of the compartment, or compartment delta pressure, which is the diastolic pressure minus the intracompartmental pressure. If this is less than 30 mmHg, then there is an imminent risk of anoxia and ischemia, and intervention is required [103]. Serial creatine kinase levels may be helpful, especially if they are increasing in a serial manner as sequentially elevated levels occur with increasing muscle damage [104]. Renal function should also be serially assessed as renal impairment may occur secondary to rhabdomyolysis [105].

4.3 Surgical Management

The procedure of choice for LLCS is urgent fasciotomy of the compartments of the below-knee compartments to allow the release of pressure. This should be done as soon as possible and usually requires the intervention of orthopedic, trauma, plastic, or general surgery depending on what expertise is available. It is vital to open the anterior compartment as this is the one most commonly affected, but more extensive fasciotomy with opening of the other compartments is often needed. Any necrotic tissue should be excised, and the compartments closed loosely. Repeat inspections of the muscle bellies under anesthesia are usually needed, and skin grafts are often employed to close the resultant defect [103].

Compartment syndrome is a surgical emergency that is rare and unexpected in urology, which puts an onus on the clinician to suspect it in any patient complaining of severe pain in the lower limb following RARP, which is not a procedure associated with lower limb pain usually. The risk is lowered by reduced operative time and keeping the legs in a flat position, as opposed to using stirrups and the lithotomy position. There is no significant association of the use of mechanical thromboprophylaxis, lithotomy position, and compartment syndrome [106]. The diagnosis is a clinical diagnosis, and once the possibility of LLCS has been raised, it is appropriate to get urgent specialist advice and proceed quickly to fasciotomy, as if LLCS is present, there will be ongoing muscle tissue destruction, with potentially catastrophic resultant outcomes.