In September 2020, a 39 year-old man was admitted to Shanghai Ruijin Hospital complaining of a serious discharge from a small opening on his left flank. It had been occurring for 2 months without fever or pain. His medical history evidenced a laparoscopic left partial nephrectomy for clear cell renal cell carcinoma (ccRCC) in December 2015. Three weeks post-surgery, he had developed purulent discharge from the drainage tube orifice on his left flank. Seven months later, after three rounds of debridement and percutaneous drainage procedures, the wound was healed. There was no report of previous tuberculosis or pyelonephritis. Physical examination revealed that the fistula covered an area of 0.5 x 0.5 cm, and 6 cm deep on his left flank without tenderness or percussed pain (Figures 1A,B). Laboratory tests including renal function tests and urinalysis showed no unusual results. Urine culture and secretion culture were negative. To rule out tuberculosis, we conducted a fluorescent quantitative PCR test of the secretions from the fistula, which was also unremarkable.
Renal dynamic imaging revealed normal function of the left kidney. Preoperative abdominal CT showed the sinus tract, extending from the surface of left kidney near the lower upper pole to the skin without renal/ureteral stone or hydronephrosis (Figures 1C-E). The three-dimensional reconstruction clearly showed the relationship between the sinus tract and the kidney (Figures 1F-H). Next, we performed a fistulous tract endoscopy, which showed a mass of white flocculus stuck to the lining of the sinus tract (Figure 2A). Given the frequent recurrence and complexity of NCF, we planned to repair the fistula and prevent relapse using complete sinus tract resection combined with omental flap grafting.
Specific steps in the surgical operation were as follows:
Complete excision of the sinus tract under the guidance of methylene blue staining. The bottom of the sinus tract was stuck to the lower pole of the left kidney (Figure 2B).
We found a substantial amount of hard tissue similar to calcification, and a hemoclip at the lower pole of the left kidney. We removed all the abnormal tissue and hemostasis (Figures 2C,F).
We opened the posterior peritoneum and pulled part of the greater omentum tissue into the retroperitoneal space with oval forceps. Then, we tightly covered the left kidney with the omental flap and fixed it with sutures (Figures 2D,E).
We sutured the posterior peritoneum with the root of the omental flap. Then, we closed the posterior peritoneum incision. Finally, we closed the operation incision in layers in the usual manner.
The pathological investigation of the resected sinus tract showed chronic inflammation with granulation hyperblastosis and foam cells growth. The patient was discharged 6 days after the operation. Six months later, MR examination showed that the NCF had healed well with the omental flap tightly covering the kidney (Figures 3A,B). The patient was asymptomatic throughout 12 months of follow-up.