Introduction
Partial cystectomy is an uncommonly performed procedure with oncologic and functional indications that determine surgical approach. Because of the risk of tumor spillage with urothelial cancers, it is rarely indicated in the management of this malignancy, but the approach can be utilized for less common bladder tumors or the excision of bladder diverticula for functional reasons. The robotic approach is particularly suited to partial cystectomy due to the enhanced surgical view compared to open surgery and significantly improved dexterity over traditional laparoscopic surgery, particularly for bladder closure.
- 1.
Access, pneumoperitoneum, port placement
- 2.
Bladder mobilization ± ureteric mobilization
Urachal remnant/tumor
- 1.
Bladder filling, cystotomy, and tumor excision
- 2.
Bladder closure
- 3.
Excision of remaining urachus and umbilicus
- 4.
Closure of rectus sheath and overlying fat
Bladder diverticula
- 1.
Partial filling of bladder and diverticulum
- 2.
Mobilization of diverticulum from adjacent structures
- 3.
Ligation of diverticular neck (for malignant indications)
- 4.
Disconnection of diverticulum from bladder
- 5.
Bladder closure
Indications and contraindications for robotic-assisted partial cystectomy (RAPC)
An overview of the indications is provided in Table 28.1 .
| Bladder | Diverticulum | Urachus |
|---|---|---|
| Malignant Conditions | ||
| ||
| Adenocarcinoma | |
| Benign Conditions | ||
| Congenital or acquired benign diverticula | Infected urachal remnants: patent urachus, urachal cyst, urachal sinus, and vesicourachal diverticulum |
Pathologies of the urinary bladder
Bladder cancer
Partial cystectomy is rarely indicated in the management of urothelial cancer due to the risk of tumor spillage and the development of implantation tumors. Chemoradiation provides a reasonable alternative in those patients not fit for or who refuse radical cystectomy. However, patients with urothelial malignancy within a bladder diverticulum may be suitable for this approach. Furthermore, those with variant histology, such as adenocarcinoma, squamous carcinoma, and neuroendocrine carcinoma, have lower risk of implantation tumors and are more suitable for partial cystectomy. Rare malignant indications also include other histological subtypes, such as spindle cell carcinoma or sarcoma. Although data are sparse, there is some evidence in the literature that partial instead of radical cystectomy in well-selected patients with variant histology does not impair survival. In carefully selected patients, partial cystectomy has functional and morbidity related advantages over radical cystectomy ( Table 28.2 ).
| Advantages | Relative Indications |
|---|---|
|
|
Among patients who recur following partial cystectomy, salvage cystectomy offers similar survival to primary radical cystectomy for organ-confined disease. The inclusion of partial cystectomy in novel trimodal therapy protocols and innovations in surgical technique offers some promise to improve patient outcomes but should be considered experimental.
The role of pelvic lymph node dissection (PLND) as part of the primary treatment and its extent is controversial. In patients with urothelial cancer, there is some evidence that PLND at the time of partial cystectomy is associated with a lower cancer specific mortality rate and improved overall survival. ,
However, for the treatment of urachal carcinoma, there is no clear evidence that lymphadenectomy is of any benefit. , Some evidence suggests that PLND, even in the presence of lymphadenopathy on imaging, is of no benefit, whereas other evidence suggests a survival benefit of up to 25% at 5 years. , , Because of the low incidence of urachal adenocarcinoma, sufficient evidence for consensus opinion will be difficult to achieve.
Benign bladder tumors
Although conventional transurethral resection is regarded as the gold standard for benign bladder tumors, partial cystectomy is considered the most effective treatment for certain benign bladder tumors, such as bladder paraganglioma, pheochromocytoma, leiomyoma, and fibrous histiocytoma.
Other benign indications
Partial cystectomy may also be performed as part of more extensive pelvic surgery, including colovesical fistula repair, vesicovaginal fistula repair, and less commonly for cavernous hemangiomas, ulcerative interstitial cystitis, and bladder endometriosis.
Bladder diverticulum
Diverticulectomy is most commonly performed for functional reasons but may rarely be indicated in patients with isolated malignancy within a bladder diverticulum.
Acquired bladder diverticula predominantly develop in adult males due to bladder outlet obstruction secondary to prostatic hyperplasia or urethral stricture. Less commonly, they may arise in male or female patients with neurogenic bladder (detrusor-sphincter-dyssynergia). Congenital diverticula are rare.
Chronic urinary stasis within bladder diverticula, especially in those with a narrow rather than wide neck, can result in bladder calculi and subsequent infections, leading to squamous metaplasia and risk of malignancy. Radical cystectomy remains the gold standard for cancer within a bladder diverticulum; however, in highly selected cases, partial cystectomy with or without multimodal therapy for high-risk tumors remains a more conservative alternative approach.
Pathologies of the urachus
After birth, the urachus becomes a fibrous cord known as the median umbilical ligament. If remnants of the allantois remain within the ligament, they may develop into cysts and epithelial or mesenchymal neoplasms. Four structural anomalies may arise: patent urachus, urachal cyst, urachal sinus, and vesicourachal diverticulum.
Urachal tumors
Urachal tumors, both benign and malignant, are rare, but the predominant type is adenocarcinoma.
Malignant urachal neoplasms account for less than 1% of all bladder cancers , and are generally treated by partial cystectomy with en bloc resection of the median umbilical ligament and umbilicus.
Benign urachal neoplasms are extremely rare and include fibromas, adenomas, fibroadenomas, fibromyomas, and hamartomas; however, they are important in that they mimic urachal malignancy.
Infected urachal remnants
All anomalies mentioned above are prone to infection. Early recognition and treatment for infected urachal remnants lowers the risk of bladder fistula or cyst rupture, both of which can elicit peritonitis, abscess, and sepsis. Surgical excision of urachal remnants in adults is not only preventive against recurrent infection but also reduces risk of malignant transformation.
Preoperative assessment
Basic investigation
In all benign and malignant bladder and urachal pathologies, standard blood tests (including complete blood count, creatinine and electrolytes, and a coagulation profile) should be performed in addition to midstream urine for culture and cytology, where indicated. Essential imaging to evaluate the local extent of the pathology and for staging includes contrast-enhanced computer tomography (CT) of the abdomen, pelvis, and chest. MRI may be indicated in specific circumstances, such as contrast allergy or local bladder tumor staging. Detailed preoperative imaging is crucial for operative planning and should include a delayed phase for pathology in close proximity to the ureters.
Rigid cystoscopy
Rigid cystourethroscopy under general anesthesia (including examination under anesthesia) must be performed in order to document the precise anatomy of tumors and bladder diverticula, assess adequate bladder volume, and obtain histological confirmation of bladder tumors and urachal remnants. Proximity of tumors to the trigone, bladder neck, and ureteric orifices should ensure a 1 to 2 cm resection margin is possible. Carcinoma in situ and multifocal tumors must be excluded. Although assessment of bladder volume is not required in all cases, it should be carried out when low bladder volume is suspected or in the setting of large tumors.
Rigid cystoscopy and biopsy for diverticula
The localization and size of the diverticulum are best investigated with a flexible or rigid cystoscope. The most common location for bladder diverticula (owing to reduced thickness of detrusor muscle) is lateral and cephalad to the ureteral orifice. In trigonal bladder diverticula, vesicoureteral reflux is often present, and the ureter can open directly into the diverticulum. Concomitant bladder outlet obstruction (e.g., prostatic hyperplasia or urethral stricture) must be treated prior to diverticulectomy to ensure low pressure voiding on removal of catheter and prevent recurrent diverticula. Any suspicious lesions within or next to the diverticulum should be biopsied to exclude a malignancy.
Rigid cystoscopy and biopsy for urachal pathology
Rigid cystoscopy and biopsy are mandatory for full evaluation of suspicious urachal pathologies. In order to diagnose a urachal carcinoma, the following criteria are required: tumor location at the dome or anterior wall of the bladder; the absence of cystitis cystica and cystitis glandularis; sharp demarcation between the tumor and surface bladder urothelium, which is free of glandular or polypoid proliferation; and histological confirmation of urachal elements within the tumor. In most patients, urachal tumors are contiguous with the median umbilical ligament on sagittal reformats of axial imaging.
Additional investigations
Urodynamic studies
Urodynamics may be of utility in the setting of voiding dysfunction and a large diverticulum, especially if bladder outlet obstruction is not obviously apparent.
Theatre and port set up
Patient preparation and positioning
Following induction of general anesthesia, the patient is placed in the supine position with all pressure points carefully padded. The arms may be secured by the patient’s side with “L” boards, being sure to avoid pressure on the ulnar nerve. After skin preparation and draping, a Foley catheter is placed. See Table 28.3 for special equipment required and Fig. 28.1 A and B for port placement and Fig. 28.1 C for operating room setup.
