Anatomic Basis for Renal Incisions
Abdominal and Chest Wall
Figs. 8.1 and 8.2 show the vascular and nervous supply to the abdominal wall muscles. The intercostal nerves emerge from below the costal margin and run between the layers of the internal oblique and transversus abdominis muscles. The rectus abdominis muscle is supplied by the superior epigastric artery, which originates from the inferior mammary artery. The lower rectus muscle is supplied in a similar manner by the inferior epigastric artery, which arises from the external iliac artery.
The inferior limit of the pleural cavity may lie anywhere between the 10th and 12th ribs. Approaching the kidney through the 11th or 12th rib requires careful mobilization of the lower edge of the pleura to avoid entering it, and incision above the 10th rib inevitably requires entry into the pleural cavity.
Fig. 8.3 shows the retroperitoneal space in the oblique view. This space is lined posteriorly by the transversalis fascia, a thin layer overlying the abdominal wall muscles and the posterior pararenal fat. Gerota fascia is composed of anterior and posterior laminae that envelop the kidney and the great vessels. These layers fuse laterally to form the lateroconal fascia, which then fuses with the peritoneum lateral to the colon to form the white line of Toldt. Superiorly, Gerota fascia attaches to the crura of the diaphragm; inferiorly, it is not fused.
The adrenal glands drape over the superior medial border of each kidney within Gerota fascia. The left and right colon and their mesenteries lie directly anterior to both kidneys. The second portion of the duodenum overlies the hilum of the right kidney. The tail of the pancreas and splenic hilum overlie the superior portion of the left kidney. The inferior mesenteric vein courses superiorly and joins the splenic vein. The take-off of both main renal arteries is generally encountered posterior to the left renal vein after it is mobilized off the aorta. It is important to remember that renal artery anatomy is variable, and there can be multiple or anomalous branches. Venous anatomy around the kidney is less variable, but a retroaortic left vein or persistent left cardinal vein are not uncommon.
Choice of Surgical Approach
The surgeon must take into account the disease process and the patient’s body habitus, known anatomic anomalies, and prior surgical history. There are two primary open surgical approaches to the kidney, anterior and flank ( Figs. 8.4 and 8.5 and Table 8.1 ).
|Anterior||Midline transperitoneal||Trauma, IVC thrombus, bilateral renal or ureteral disease, horseshoe kidney||Familiar, rapid, less painful, access both kidneys, early vascular control||Limited exposure to the kidney, bowel complications, wound dehiscence|
|Subcostal||Radical nephrectomy, UPJO||Incision can be extended to chevron or flank, early vascular control||Bowel complications|
|Chevron||Bilateral renal tumors, IVC thrombus, polycystic bilateral nephrectomies, local tumor extension or invasion||Excellent bilateral exposure, early vascular control||Injury to liver and spleen, transection of large muscles|
|Transverse abdominal||Pediatric Wilms tumor||Easy access to the renal pedicle and retroperitoneal nodes||—|
|Paramedian||Avoidance of another structure (e.g., colostomy)||Facilitates development of the preperitoneal space in extraperitoneal approach||Risks injury to superior epigastric artery; similar risks as laparotomy|
|Modified thoracoabdominal||Radical nephrectomy, lymphadenectomy||Versatile||Bowel complications, transection of large muscles|
|Flank||11th or 12th rib supracostal||Partial nephrectomy, simple nephrectomy, simple adrenalectomy||Good renal and retroperitoneal exposure||Pleural injury|
|11th rib transcostal||Partial nephrectomy, simple nephrectomy, simple adrenalectomy||Good renal and retroperitoneal exposure||Pleural injury, noticeable flank defect|
|Thoracoabdominal||Large renal mass, IVC thrombus, adrenal mass, involvement of surrounding structures, lymphadenectomy||Excellent exposure, can approach completely extraperitoneally||Pleural injury, transection of large muscles, bowel complications if intraperitoneal|
|Avoidance of bowel complications||Open ureterolithotomy (historical), open drainage of psoas abscess||Limited access|
|Avoidance of bowel complications||Open renal biopsy, drainage of perinephric abscess, pyeloplasty (extrarenal pelvis)||Limited access, flank bulge/diastasis|
An anterior transperitoneal incision is a popular approach for major procedures of the kidney, ureter, and adrenal gland, and it is one that is familiar to most surgeons. Opening and closure are very rapid and provide an opportunity to evaluate other intraabdominal organs, allow rapid access to the renal hilum, and afford good control of the great vessels if they are injured. Pain is also minimized by avoiding muscle division. However, a standard midline laparotomy provides relatively poor access to the kidney because the renal hilum is at the upper limit of the incision and the overlying colon, liver, and spleen must be mobilized widely. There is risk of late bowel obstruction and incisional hernia.
Similarly, a standard anterior subcostal incision gives very limited visibility, so it is best reserved for small renal tumors or benign conditions. Better anterior access may be gained from incisions that divide the rectus abdominis, such as the hockey-stick incision, extended subcostal, or bilateral subcostal (Chevron). For complex kidney tumors requiring access to the chest, a bilateral subcostal incision with the cephalad median sternotomy extension (Mercedes incision) or a high thoracoabdominal incision can give maximum exposure.
A standard flank incision has the advantage of direct access to the kidney and the ability to avoid entry into the peritoneal cavity. Therefore, bowel complications are minimized. However, lateral incisions necessitate division of large muscles, risks injuring nerves, and may result in postoperative flank bulge or hernia as well as significant pain. Additionally, the vascular pedicle on the opposite side of the kidney from the one exposed. Using cross sectional imaging, a horizontal line drawn from the kidney over to the lateral edge of the rib marks the highest level that is easily accessed from that level of flank incision. This approach is more appropriate for partial nephrectomies, repair of ureteropelvic junction obstruction, open stone surgeries, and drainage of renal or perirenal abscesses.
Midline Transperitoneal Incision (Laparotomy)
This is the basic laparotomy incision that is familiar to all general and urologic surgeons. It is simple, rapid to open and close, and less painful than flank or transverse abdominal incisions that require division of major muscle groups. It provides good exposure to the peritoneal cavity but limited exposure to the kidneys because of the location of the renal hilum superiorly. It is useful in a trauma setting, when both ureters must be accessed (e.g., retroperitoneal fibrosis), or for approaching a horseshoe kidney.
Position the patient supine with the table extended at the patient’s waist. Make an incision in the midline from the xiphoid to just below the umbilicus. Divide the subcutaneous tissue down to the level of the fascia and identify the linea alba. Lifting up on the skin at the upper end of the incision helps identify the linea alba as a ridge in the fascia. Incising the linea alba will expose the preperitoneal fat covering the peritoneum. Grasp of the preperitoneal fat, taking care not to include the underlying loops of bowel and sharply cut through this layer. When the peritoneum is opened, the loops of bowel will naturally drop away unless there are adhesions. The remainder of the posterior rectus fascia and peritoneum may be opened with care taken to identify any adhesions between the bowel and the anterior abdominal wall.
The renal vessels may be approached through the posterior peritoneum by displacing the patient’s small bowel contents to the right and the descending colon to the left. The peritoneum is first divided over the aorta between the fourth portion of the duodenum and the inferior mesenteric vein ( Fig. 8.6, A ). Both of these structures are usually easy to identify, even the case of severe retroperitoneal hemorrhage. There are no vessels arising off of the anterior aorta in this area as long as one stays above the takeoff of the inferior mesenteric artery (IMA). The retroperitoneal fat over the aorta is divided superiorly up to the left renal vein. The renal vein is dissected above and below with care taken not to injure the superior mesenteric artery (SMA) at its take-off from the aorta just above the left renal vein ( Fig. 8.6, B ). The left and right real arteries are usually encountered coursing directly lateral off the aorta posterior to the left renal vein though multiple arteries may arise anywhere from above the level of the SMA down to the common iliac arteries.
The right kidney is approached from the midline by incising along the lateral edge of the right colon on the avascular line of Toldt, continuing up around the hepatic flexure ( Fig. 8.7, A ). As the colon is mobilized medially, the second portion of the duodenum is encountered. Dissecting posteriorly, it is mobilized medially as well (Kocher maneuver) over to the aorta ( Fig. 8.7, B ). One then encounters the anterior aspect of the inferior vena cava (IVC) and the anterior leaf of Gerota fascia overlying the right kidney.
The left kidney is similarly approached by incising lateral to the left colon and taking down the splenocolic ligament to mobilize the colon and spleen medially off of Gerota fascia.
In a radical nephrectomy, the upper limit of Gerota fascia must be separated from the lower edge of the pancreatic tail and splenic hilum. After the abdominal contents are mobilized off Gerota fascia, a self-retaining retractor can be placed to keep the intestines out of the way for the remainder of the operation.
Closure : The midline incision may be closed in an interrupted or continuous fashion using permanent or absorbable suture materials. Generally, a one-layer closure is performed.
Extraperitoneal Approach—Left Side.
This approach is more practical on the left side, where the spleen and peritoneal contents can be readily mobilized anteriorly. The liver limits the ability to mobilize the peritoneum off Gerota fascia from this approach on the right; therefore, other incisions are preferred.
Position the patient supine with the table flexed at the patient’s waist. If desired, the shoulder can be turned up 30 to 40 degrees and the ipsilateral arm placed over the head on support. Start the incision in the midline anteriorly, one third of the distance from the xiphoid to the umbilicus. End the incision on the left at the tip of the 11th rib near the anterior axillary line ( Fig. 8.8 ). Divide the left side of the anterior rectus sheath and the external oblique muscles for a short distance. The rectus muscle may be divided with electrocautery, making sure to control the superior epigastric artery. Divide or bluntly split the internal oblique and digitally separate the fibers of the transversus abdominis, starting as far laterally as possible, where the peritoneum is less adherent ( Fig. 8.9 ). Incise the transversalis fascia and free the peritoneum off above and below the incision. Sweep the peritoneum bluntly off the abdominal wall laterally and inferiorly to the iliac crest. Continue posteriorly to the lateral edge of psoas muscle in the extraperitoneal space and bluntly strip the peritoneum from the overlying muscle layer. Some sharp dissection with scissors may be required. To develop the plane between the peritoneum and the anterior leaf of Gerota fascia, incise the transversalis fascia just outside the reflection of the peritoneum laterally. This should be filmy, fibroareolar tissue in an avascular plane, and the gonadal and ureter should remain posteriorly.
If a radical nephrectomy is indicated ( Table 8.2 ), the renal vessels may be encountered at the level of the aorta, ligated, and divided. Gerota fascia is divided above the kidney, carefully mobilizing it off of the lower edge of the pancreas. The lower limit of Gerota is divided above the common iliac artery, and the ureter and gonadal vessels are divided. The posterior and medial attachments are divided, and the kidney is removed within Gerota fascia.
|Patient characteristics||Renal tumor occurring in a nonfunctional kidney|
|Patient would not tolerate complications of partial nephrectomy|
|Tumor characteristics||Large tumor replacing most of the kidney|
|Central renal tumors in a patient with a normal contralateral kidney|
|Numerous tumors involving most of the parenchyma|
|Tumors associated with regional lymphadenopathy (debatable)|
|Tumors associated with tumor thrombus|
|Tumors associated with metastases (cytoreductive nephrectomy)|
|Other||Difficult partial nephrectomy requiring intraoperative conversion|