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  • Open Partial Nephrectomy For a Small Renal Mass (Subcostal Incision)

    Gabriel Varga, MD, Dalibor Pacík, MD, Prof.,  Vítězslav Vít, MD,

    About the authors

    Dr. Gabriel Varga is assistant professor in the department of urology, Faculty Hospital of Masaryk University, in Brno, Czech Republic. Since 2005 he has been working as an assistant professor for the Faculty of Medicine and has served as a senior supervising physician since 2008.  In 2009 he became a certified urologist.

    Professor Dalibor Pacík is a Chairman department of Urology University Hospital Brno since 1990. He is a member of Czech Urological Society (for 18 years was member of Executive Board he served as  Vice President and Treasurer), member of EAU, World Endourological Society, International member of AUA.

    Video

    Introduction

    Partial nephrectomy is a surgical procedure, which involves removing a portion of the kidney. This procedure is often performed as the initial step in the treatment of early stages of kidney cancer in which the tumor is removed with the surrounding adipose tissue.

    Indications

    Among others, the indications for this nephron sparing surgery include:

    • Anatomical or functional solitary kidney affected with tumor
    • Functional impairment of the contralateral kidney, in case when radical nephrectomy would worsen its function in the future
    • Well-localized tumor of a limited size  with a healthy contralateral kidney (1).

    Contraindications

    The absolute contraindications include uncorrected coagulopathy, active urinary tract infection and inability to undergo surgery under general anesthesia.

    Special anatomical considerations.

    The renal pedicle usually consists of a single artery (branch from aorta) and a single vein (branch of inferior vena cava) that enter the kidney via the renal hilum. The vein is typically anterior to the artery. The renal pelvis and ureter are located posterior to these vascular structures (2).

    Renal artery

    Specifically, the right renal artery leaves the aorta and continues with a caudal slope under the IVC toward the right kidney. The left renal artery courses almost directly laterally to the left kidney. Given the rotational axis of the kidney both renal arteries move posteriorly as they enter the kidney. Both arteries have branches to the respective adrenal gland, renal pelvis, and ureter.

    Upon approaching the kidney, the renal artery splits into four or more branches, with five being the most common. These include the renal segmental arteries. Each segmental artery supplies a distinct portion of the kidney with no collateral circulation between each other (ie “end arteries”). Thus complete occlusion or injury to a segmental branch will cause segmental renal infarction. Generally, the first and the most constant branch is the posterior segmental branch, which separates from the renal artery before it enters the renal hilum. There are typically four anterior branches, which (from superior to inferior) are apical, upper, middle, and lower. The relationship of these segmental arteries is important because the posterior segmental branch will pass posterior to the renal pelvis, while the others pass anterior to the renal pelvis.

    Renal Veins

    There is greater variety to the venous anatomy. The renal venous drainage correlates closely with the arterial supply. The interlobular veins drain the post-glomerular capillaries. These veins also communicate freely via the subcapsular venous plexus of stellate veins with veins in the perinephric fat. Behind the interlobular veins, the venous drainage progresses through the arcuate, interlobar, lobar, and segmental branches, with the course of each of these branches paralleling the respective artery. After the segmental branches, the venous drainage coalesces into three to five venous trunks that eventually combine to form the renal vein. Unlike the arterial supply, the venous drainage communicates freely through venous collars around the infundibula, providing for extensive collateral circulation in the venous drainage of the kidney. Surgically this is important, because unlike the arterial supply, occlusion of a segmental venous branch has little effect on venous outflow. The renal vein is located directly anterior to the renal artery, although this position can vary up to 1-2cm cranially or caudally, relative to the artery. The right renal vein is generally 2 to 4cm in length and enters the right lateral to posteriolateral edge of the IVC.

    The left renal vein is typically 6 to 10cm long and enters the left lateral aspect of the IVC after passing posterior to the superior mesenteric artery and anterior to the aorta. Additionally, the left renal vein receives the left adrenal vein superiorly, lumbar vein posteriorly, and left gonadal vein inferiorly. The right renal vein typically does not receive any branches.

    Anatomic variations in the renal vasculature are common, occurring in 25% to 40% of kidneys. The most common variation includes supernumerary renal arteries, with up to five arteries reported. This occurs more often on the left. These additional arteries can enter through the hilum or directly into the parenchyma. The lower pole arteries on the right tend to cross anterior to the IVC whereas lower pole arteries on either side can cross anterior to the collecting system, causing ureteropelvic junction obstruction. Supernumerary veins occur as well, but this is a less common entity.

    Anatomic Relationships

    Anteriorly, the right kidney is bordered by a number of structures. Cranially, the upper pole lies against the liver and is separated from the liver by the peritoneum except for the liver’s posterior bare spot. The hepatorenal ligament further attaches the right kidney to the liver because this extension of parietal peritoneum bridges the upper pole of the right kidney to the posterior liver. Also at the upper pole, the right adrenal gland is encountered. On the medial aspect, the descending duodenum is intimately related to the medial aspect of the kidney and hilar structures. Finally, on the anterior aspect of the lower pole lies the hepatic flexure of the colon.

    The left kidney is bordered superiorly by the tail of the pancreas with the splenic vessels adjacent to the hilum and upper pole of the left kidney. Also cranially to the upper pole is the left adrenal gland and further superolaterally we can find the spleen. The splenorenal ligament attaches the left kidney to the spleen. This attachment can lead to splenic capsular tears if excessive downward pressure is applied to the left kidney. Superior to the pancreatic tail, the posterior gastric wall can overlie the kidney. Caudally, the kidney is covered by the splenic flexure of the colon (2).

    Gerota’s Fascia

    Interposed between the kidney and its surrounding structures is the perirenal or Gerota’s fascia. This fascial layer encompasses the perirenal fat and kidney and encloses the kidney on three sides: superiorly, medially, and laterally. Superiorly and laterally Gerota’s fascia is closed, but medially it extends across the midline to fuse with the contralateral side. Inferiorly, Gerota’s fascia is not closed and remains an open potential space. Gerota’s fascia serves as an anatomic barrier to the spread of malignancy as well as a means of containing perinephric fluid collections (2).

    Surgical technique

    Patient positioning and access to the kidney depend on the location of the tumor and eventually the necessity of warm ischemia with prompt securing of the renal vascular hilum.  Approaching the kidney is possible through subcostal incision, midline laparotomy or lumbotomy without entering the peritoneal cavity. Small tumors located on the convexity of the lower pole can be accessed by the subcostal approach. As seen in the video, the patient is placed in the modified lateral flank position; this involves placing the patient in the lateral position, hyperextending the tumor side by flexing the table and placing a lumbar support, the underlying lower leg is flexed at the knee and the upper leg slightly extended. The shoulder on the operating side is abducted and bent at the elbow while the forearm is fixed.

    Subcostal Incision

    The 12th rib is identified by palpation and the skin incision is performed beneath the 12th rib. The skin incision is prolonged laterally towards the outer border of the erector spinae muscles and inferiomedially towards the anterior superior iliac spine (ASIS). The incision is gradually carried through the latissimus dorsi muscle on the posterior and through the external oblique and internal oblique muscles. Careful attention must be paid to the subcostal nerve, which travels on the surface of the internal oblique muscle. The third layer is the transversus abdominis muscle, and its fascia is mainly visible in the dorsal part of the incision. The fascia is opened beneath the tip of the 12th rib, the peritoneum is swept medially with the hand and the incision is terminated (3). The operative field is then held in place with retractors. After opening the Gerota’s fascia, the kidney is dissected and freed from the surrounding adipose tissue in such a way that the tumor is left in place with its surrounding adipose tissue intact. The ureter and the renal vascular hilum are dissected, Preparation of the renal hilum allows for prompt renal arterial occlusion if required. For smaller tumors, it is sufficient to compress the renal parenchyma with fingers of the unengaged hand or with fingers of the assistant. The video demonstrates the placement of a vascular clamp on the renal hilum. However, resection was performed without clamping or “warm ischemia”.

    Removal of the tumor involves sharp resection of the pathologic process to healthy parenchymal tissue, and confirmation with operative histology, that there is no residual tumor present at the surgical margins. If the tumor is completely removed, the thickness of the surgical margins does not affect the probability of local tumor recurrence (4). In cases where the resection encompasses part of the renal calyces, it is necessary to suture the defect with absorbable sutures. Bleeding from arteries are controlled by absorbable suture ligation and the renal parenchyma is sutured with absorbable material over bolsters of hemostatic material (see video recording). After fastidious control of hemostasis, proceed to close the surgical wound by approximating the anatomical layers. A temporary drain can be introduced and placed behind the kidney.

    Potential complications of the surgery

    The common postoperative complications include bleeding, urinary leakage with potential formation of urinoma, and infectious complications.

    References

    1. B. Ljungberg, N. Cowan, D.C. Hanbury, M. Hora, M.A. Kuczyk, A.S. Merseburger, P.F.A. Mulders, J-J. Patard, I.C. Sinescu. EAU Guidelines on Renal Cell Carcinoma: The 2010 Update. Eur Urol 2010; 58 (3): 398-406.
    2. Anderson JK et all. Surgical Anatomy of the Retroperitoneum, Adrenals, Kidneys, and Ureters.  In: Wienn AJ et all. Campbell-Walsh Urology, 9th ed. Philadephia: Saunders Elsevier,  2007. p. 24-30. ISBN 13: 978-0-7216-0798-6
    3. Zvara V. , Horňák M. et all. Kidney. In: Urological Surgery. Martin: Osveta Publishing,  2010:  11-41. ISBN 978-80-8063-338-7 .
    4. Bensalah K, Pantuck AJ, Rioux-Leclercq N, et al. Positive surgical margin appears to have negligible impact on survival of renal cell carcinomas treated by nephron-sparing surgery. Eur Urol 2010 Mar; 57(3):466-71.

     

     

     

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