Pitfalls of subcapsular nephrectomy: Report of a case with point of technique to avoid urinary fistula formation
R Nayyar, P Singh, NP Gupta
Department of Urology, All India Institute of Medical Sciences, New Delhi-110 029, India
Department of Urology, All India Institute of Medical Sciences, New Delhi-110 029
Nephrectomy after pyonephrosis, repeated acute pyelonephritis or chronic pyelonephritis is a challenge for any surgeon, owing to adhesions around the kidney. We encountered an unusual case of post-nephrectomy urinary fistula, as a complication of subcapsular nephrectomy. This occurred as a result of residual renal tissue after nephrectomy, which was subsequently excised using methylene blue as an aid to ensure complete excision. Such a complication has never been reported in existing literature. We reviewed the literature for any such related complications to gather an insight to its occurrence and also present a simple point of technique to avoid such a catastrophe.
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Nayyar R, Singh P, Gupta N P. Pitfalls of subcapsular nephrectomy: Report of a case with point of technique to avoid urinary fistula formation.J Postgrad Med 2010;56:24-26
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Nayyar R, Singh P, Gupta N P. Pitfalls of subcapsular nephrectomy: Report of a case with point of technique to avoid urinary fistula formation. J Postgrad Med [serial online] 2010 [cited 2022 Jun 30 ];56:24-26
Available from: https://www.jpgmonline.com/text.asp?2010/56/1/24/62433
Nephrectomy for benign pathologies may sometimes present a challenge to the operating surgeon because of significant perinephric adhesions and difficult hilar dissection. , Subcapsular nephrectomy is advocated in cases where perinephric dissection may jeopardize the integrity of viscera lying in relation to the kidney. Apart from a relatively difficult hilar vessel dissection, not many pitfalls or complications have been reported with regard to subcapsular technique of nephrectomy. We report a case of urinary fistula following subcapsular nephrectomy for hydronephrotic non-functioning kidney and also present an insight into the possible problems which led to this complication along with a simple technical nuance to avoid its occurrence.
Two years ago, a 26-year-old male presented with recurrent nausea/vomiting and decreased urine output. He was diagnosed as a case of congenital solitary left kidney with grade 4 vesico-ureteric reflux following recurrent urinary tract infections, 12 years ago. He had undergone left ureteric reimplantation at that time. He was found to be suffering from uremia with blood urea of 200 mg/dl and serum creatinine of 8 mg/dl. Left percutaneous nephrostomy was done, but no recovery of renal function was noted with urinary output of 400cc/day. Patient was diagnosed with end stage disease and advised renal transplantation. He was maintained on regular hemodialysis during the two-year waiting period for transplant.
Now, he has been admitted for pre-transplant nephrectomy. A rib cutting flank approach was used for nephrectomy. Per-operatively, the kidney was found to be densely adherent to surrounding tissues including peritoneum, colon, spleen, psoas muscle and diaphragm. Ureter was also thickened and dilated. We thus proceeded with subcapsular nephrectomy with excision of the ureter up to pelvic brim. The histopathology confirmed 7.8 × 6 × 4 cm specimen of kidney with evidence of chronic pyelonephritis and dilated thickened ureter showing ureteritis. The postoperative course seemed uneventful till the fifth postoperative day when the patient developed watery discharge from the main wound. Abdominal ultrasound revealed a 7 × 6 cm loculated collection in left renal fossa for which a pigtail catheter was placed draining 100-150 ml clear fluid per day. Drain fluid creatinine was 8 mg/dl confirming a urinary fistula. A pigtail dye study, MCU and CECT abdomen [Figure 1] confirmed residual renal tissue with urinoma.
Patient was planned for cystourethroscopy and reexploration. Left hemitrigone was seen on cystoscopy but the native left ureteric orifice could not be cannulated. The new ureteric orifice of the ureteric reimplantation was wide open on the posterolateral wall and the right ureteric orifice was absent. All these investigations confirmed the absence of a congenital contralateral renal ectopia to the left side as a cause of post nephrectomy urinary fistula and it was obviously a case of residual renal parenchyma at the upper pole.
A re-exploration was done through the 11th rib flank approach. Methylene blue was injected through the pigtail catheter to delineate the entire residual pelvicalyceal system and the fistulous tract [Figure 2]. The residual portion of the kidney was found to be very densely adhering to the surrounding tissues along with its separate residual arterial supply. The methylene blue injection proved to be immensely helpful in complete extirpation of the renal tissue without injuring the adjacent adherent structures. This time kidney tissue could be removed extracapsularly. The histopathology again confirmed the hydronephrotic renal tissue that showed chronic pyelonephritis changes. The postoperative course was uneventful this time and the patient underwent a live donor renal transplant one week later.
Subcapsular nephrectomy is often reported as the pariah of the operating surgeon in cases where it becomes difficult to identify a clear plane between the renal capsule and the surrounding fat during nephrectomy.  It helps avoid injury to the surrounding structures lying in relation to the kidney, most importantly, the duodenum, colon and vena cava on the right side; and the colon, superior mesenteric artery, duodeno-jejunal flexure and aorta on the left side. Though most cases can be completed successfully without any complication, subcapsular dissection makes hilar vessel dissection cumbersome. There is also a chance of entering the calyces and leaving a portion of parenchyma behind, particularly if the kidney is grossly hydronephrotic with thinned out parenchyma. The risk of such remnant renal parenchyma is obviously more with subcapsular technique than classical extracapsular or extrafascial approach.
Residual parenchymal tissue may produce a urinary fistula further increasing the perioperative morbidity, as it happened in the present case. On retrograde analysis, all risk factors enumerated above were present in our case including (1) use of 'subcapsular approach' (2) a 'large' hydronephrotic kidney, and (3) 'very thin parenchyma'. This was the first instance of such a complication in our experience of more than 600 cases of nephrectomy for benign cases over the last decade.  No similar case has been recorded in literature on complications following subcapsular nephrectomy. Surely, the occurrence of any complication is also related to the surgeon's experience. However, complications are associated with any difficult surgery and should be reported for the learning of the surgical fraternity.
Use of methylene blue to delineate the renal pelvicayceal system can be a simple adjunct to facilitate complete removal of all parenchyma. Its use has earlier been reported for various other indications including excision of the fistulous tract during surgery for urethrocutaneous fistula, complex vesicovaginal or ureterovaginal fistula, anocutaneous fistula, partial nephrectomy etc. ,, However, its use to facilitate complete excision of renal tissue has not been reported earlier. In this case, we believe that the use of methylene blue during the first surgery itself could have helped in avoiding the formation of a urinary fistula by ensuring complete removal of renal parenchyma. Advantages gained by coloring the pelvi-calyceal system with the dye included better identification of collecting system by differentiating from adherent tissues, avoidance of unintentional entry into the collecting system during dissection and ensuring complete extirpation of the parenchyma. These benefits are more apparent when the renal parenchyma itself is very thin. This is because chances of entering into the pelvicalyceal system are correspondingly higher.
We conclude that the use of methylene blue to stain the pelvicalyceal system is a simple technical nuance to avoid incomplete excision of parenchyma and post-operative urinary fistula formation. Besides the use of methylene blue, other important factors behind the success of second surgery included the use of 11th rib approach for better access to the upper pole and detailed pre-operative imaging to define adjacent anatomical planes and therefore better preparedness for the surgery. These factors are extremely important and their importance to achieve the desired outcome cannot be underplayed. Disadvantages that may be associated with use of a dye include spreading of the dye over the entire surgical area which may make differentiation between the tissues difficult. To avoid this, we instilled the dye through the nephrostomy tube (pigtail catheter) and drained it immediately by keeping the drain tube open. This way the pelvicalyceal system was empty, thereby avoiding discoloration of adjacent tissues. Similar to use of methylene blue, intravenous injection of indigocarmine could also have been a good adjunct to complete excision of the residual renal tissue. It can also be used for the diagnosis of a urinary fistula. However, the issues associated with intravenous injection of dyes include (1) poor excretion of dye in the poorly functioning kidney and therefore inadequate or patchy coloring effect, (2) systemic side effects of the drug, and (3) some discoloration of all well perfused tissues which may hamper identification of tissue planes.
In this case, nephrectomy was being done to remove all focus of infection before receiving allograft transplantation. So, second surgery was also done to enable the patient to receive transplanted kidney. In any other case, angiography and angioembolization could have provided an easier alternative though it is associated with risks of mycotic emboli in the presence of an infected system.
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