PL is a rare benign disease characterized by excessive deposition of fat in the pelvis leading to compression of pelvic organs, resulting in a series of urinary and gastrointestinal symptoms. In 1959, Engels et al.[11] reported for the first time that a large amount of adipose tissue developed in the pelvis in five patients. Afterwards, Fogg et al.[12] first introduced the concept of PL.
Although PL is considered to be a benign disease, overgrowth of adipose tissue can lead to the wrapping of the distal ureter. If not treated in time, it can lead to upper urinary tract obstruction and subsequent renal failure[13–15], which seriously affects the quality of life of patients. At present, recognized therapeutic strategies have not been established. Conservative treatment and surgical intervention can both be adopted, depending on the specific conditions of a patient. Conservative treatment options for PL may include steroids, antibiotics, radiotherapy, exercise, and dietary management. However, these therapeutic effects are limited, and it is generally suitable for mild symptoms. Surgical options in patients with urinary tract obstruction secondary to PL consist of percutaneous nephrostomy, ureteral stent implantation, ureteral reimplantation, urinary diversion, pelvic fat removal[1,3,6−8]. In 2019, Ge L et al.[3] reported 8 patients with pelvic lipomatosis (PL) treated by pelvic fat clearance combined with ureteral reimplantation. The median operation time was 150 minutes and the median estimated blood loss was 75 ml. The median postoperative hospital stay was 8.5 days. The imaging examination at the first follow-up showed that hydronephrosis was relieved in varying degrees, and the urinary system symptoms of 3 patients were gradually relieved after operation. During a median follow-up of 48.5 months (10–100 months), one patient underwent radical cystectomy and Bricker ileal conduit surgery due to recurrence of hydronephrosis 49 months after operation. In 2020, Sanjay Prakash et al.[1] represented that five patients with PL underwent robot assisted laparoscopic extensive bladder fat removal and bilateral ureteral reimplantation, with a median operation time of 126 (range 120–130) min and a median blood loss of 120 (range 100–150) ml. The postoperative complications of 3 cases were Clavien-Dindo grade I, and the median hospital stay was 2 days. During the initial 3-month and annual follow-up, serum creatinine of all patients was normal and there was no evidence of disease recurrence, but the study was limited by small sample size and short follow-up time. Flor JMS et al.[6] reported a 43-year-old man with bilateral distal ureteral obstruction secondary to PL with proliferative cystitis and severe hydronephrosis. The patient underwent urinary diversion and percutaneous nephrostomy to prevent further renal injury. Baas w et al.[7] described a 62-year-old male PL patient with bilateral ureteral obstruction associated with venous obstruction. They solved the problem of persistent right ureteral obstruction with double-J ureteral stent. However, the ideal surgical approach still remains unclear.
In 1968, Fogg LB et al.[12] first reported that ileal conduit was used to treat PL patients with severe obstruction of the lower ureters. The operation process was difficult, but during the two-year follow-up, the patients felt good without any discomfort. David B et al.[16] reported 13 patients with PL, and more than 40% of patients received permanent urinary diversion. Buitrago S et al.[8] represented three PL patients with irritative lower urinary tract symptoms. Three patients received Bricker Wallace type II urinary diversion and well controlled irritative symptoms. Xu T et al.[17] performed ileal conduit surgery on a pair of brother patients with pelvic lipomatosis complicated with renal failure and upper urinary tract hydronephrosis, and the postoperative creatinine decreased. Yang K et al.[9] reported a male patient with PL who underwent traditional Bricker ileal conduit operation. One year after operation, the left ureteroileal anastomotic stricture occurred again due to further fat growth. It can be seen that the traditional Bricker operation still faces the problem of recurrent ureteral stricture caused by the continuous growth of fat because of the low position of the anastomosis. Compared with the traditional Bricker ileal conduit diversion, our modified surgical techniques mainly focused on the following three improvements: 1. High ureteral drainage; 2. The left ureter was anastomosed end-to-end with ileal bladder in situ, and the right ureter and ileum were anastomosed end-to-side; 3. Pelvic fat was not removed. First of all, pelvic fat may eventually develop upward to the retroperitoneal space, which will harden the retroperitoneal space fat, compress the ureter, and possibly cause ureteral recurrent structure. We decided to perform urinary diversion for patients with PL at the level of the lower renal pole. In addition, in the traditional bricker surgery, the left ureter will be moved from the retroperitoneum to the right side, anastomosed with the ileal bladder, and the distal ileum will be used for skin stoma. This technique can make the left ureter pass through the retroperitoneal space again. The fat in the retroperitoneal space may reharden, resulting in the obstruction of the ureter once again[9]. In our modified Bricker operation, the left ureter was anastomosed end-to-end with the ileal bladder at the level of the inferior pole of the left kidney, and the right ureter was anastomosed directly with the ileal bladder at the level of the inferior pole of the right kidney, and then the distal end of the ileal bladder was sewn into a papilla and fixed to the abdominal wall with suture. Because the modified method directly allows the left ureter to pass through the abdominal cavity for end-to-end anastomosis with the ileum, the recurrent stricture of the left ureter caused by hardening of retroperitoneal fat can be avoided. Third, it has been acknowledged that removal of adipose tissue has limited efficiency in patients with PL[5, 18, 19]. As adipose tissue is likely to grow after the removal of fat[20], we decided to preserve the patient's pelvic fat. Furthermore, many risks can not be overlooked, including infection, bleeding, and injury of pelvic organs.
There are still some limitations in this study. Because cases of PL are rare, only 6 patients were included in our study, which is a relatively small number. In addition, the current follow-up time for PL is short, and further follow-up is needed to evaluate the long-term prognosis of patients with PL.