Definition and Overview

Nephrotomy is a surgical procedure wherein the kidney is incised. It is usually performed as part of a more extensive open surgery procedure (such as radial nephrolithotomy and anatrophic nephrolithotomy, among others), typically for the removal of urinary tract stones.

Several decades ago, before the advent of shockwave therapy and minimally invasive surgical techniques in urology, the treatment of stones in the urinary tract involved open surgery. However, in recent years, the use of open surgery for stone removal has become limited to complex cases, cases requiring aggressive management, or in situations where endoscopic procedures are unsuccessful and the patient remains symptomatic. In most centres worldwide, the rates of open stone surgery have been brought down to 5%, with some institutions reporting rates of 1% or even less.

Who Should Undergo and Expected Results

With the advancements in medical technology, only a few indications remain for open surgery in kidney stone patients. These include:

Open surgery is indicated for large and complex stones that commonly affect the kidneys and the ureter. Those with staghorn calculi may also be managed with open surgical extraction, as these patients typically require multiple treatments to fully clear the urinary tract affected by stones. Diminished hospital stay and faster recovery may actually be achieved in these cases if open surgery is performed. This is especially true for patients with accompanying physiologic abnormalities and co-morbidities, such as sepsis and a barely functioning kidney, as more aggressive management may be necessary in these conditions. In high-risk patients with rapidly declining renal function, subjecting them to a single instance of open surgery and general anaesthesia may be more beneficial than multiple treatments.

Open surgery may also better serve patients with stones and associated anatomic defects in the urinary tract, which typically contribute to the development of urinary stones in the first place. For example, an obstruction in the ureteropelvic junction caused by an anomalous vessel, with associated kidney or ureteral stones, may necessitate open surgery with nephrotomy. Open surgery may also be preferred over less invasive treatment modalities in patients with certain congenital anomalies, such as those with horseshoe or ectopic kidneys. In this group of patients, concomitant extraction of the stones and repair of the anatomic problems permit both the treatment of the condition and prevention of stone recurrence.

Another indication for open surgical removal of kidney stones is the failure of less invasive techniques of stone extraction, including endoscopic techniques and shock wave lithotripsy. Some patients with strictures or stenoses in the ureter not amenable to endoscopic dilatation may require open surgical extraction of stones.

In the past, selected cases of hydronephrosis with obstructing stones were treated with nephrotomies. Also, in some institutions, nephrotomies are being utilised in nephron-sparing kidney surgery for small tumours or masses in the kidneys. In selected patients, outcomes are similar to those undergoing more extensive resections.

How is the Procedure Performed?

Nephrotomy allows access to the renal parenchyma and is typically a component of a more complicated procedure for stone extraction such as radial nephrolithotomy, anatrophic nephrolithotomy, pyelolithotomy, and pyelonephrolithotomy, to name a few.

The majority of the open surgeries performed on the kidneys are approached via a flank incision. For this incision, the patient is made to face the side opposite the affected kidney, and the body is made to bend, with the flank elevated. An oblique incision over the 11th or 12th rib is made, and dissection proceeds extraperitoneally until the kidney and the ureters are exposed.

A nephrotomy involves a sharp incision over the capsule of the kidney, after which, blunt dissection of the renal parenchyma is performed to minimise injuries to the small renal arteries. The stones are then located and gently extracted with special forceps. Irrigation is then performed to ensure that all stone fragments are removed. In some cases, multiple nephrotomies, usually using small incisions, may be necessary.

Sutures are then placed to close the parenchyma. Bleeding vessels are addressed by suture ligation. The renal capsule is then closed with a chromic or a monofilament suture. A stent or a nephrostomy tube may also be inserted, depending on the operation performed. Drains are usually left for several days.

Possible Risks and Complications

A nephrotomy can result in several complications. Infection is a risk, especially if there is already an ongoing infection prior to the operation. Cutting through the kidney damages not only the parenchyma but the end-arteries, as well. Thus, the segments supplied by these arteries may atrophy, adding further to the loss of renal function of the patient. Bleeding and haemorrhage may also occur during the operation; these are usually controlled by the application of suture ligatures on the renal parenchyma. In some instances, excessive and inadvertent damage to the parenchyma and the vessels may lead to a more extensive operation than initially planned, such as a heminephrectomy or even a nephrectomy.

Reference:

  • Mastery of Surgery, 5th edition
  • Urinary Tract Stone Disease
  • https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1761612/
  • https://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-55382012000300008
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