Preoperative imaging

LDN requires accurate preoperative radiographic imaging to identify any vascular or anatomic variations that may influence operative technique and/or exclude a potential donor. MR imaging angiogram and CT angiogram have replaced standard renal arteriography in defining the vascular anatomy . Both modalities also allow evaluation of the kidneys for any stones, lesions, malformations, and approximate estimates of differential renal function . Bhatti and colleagues prospectively compared CT and MR imaging angiography for evaluating the renal vascular anatomy in potential living donors and found that both had good sensitivity for detecting major arteries and veins (100% for CT, 97% for MR imaging). CT angiography, however, did much better at detecting small accessory renal arteries and accessory renal veins. Bhatti and colleagues felt a multidetector CT angiography should be the study of choice . Either modality, however, requires three-dimensional reconstruction of the images, which can be labor-intensive for radiology technicians/radiologists. Schlunt and colleagues found that the sensitivity of CT angiogram also was improved when the films were reviewed by the radiologist and operative surgeon together. Therefore, the decision on preoperative imaging choice often depends on the resources available at the institution and the radiologist’s and urologist’s preference to obtain the most accurate imaging.

Kidney selection (left versus right)

The selection of which kidneys are acceptable for transplantation and the donor side varies widely among transplant centers. The left donor kidney generally is preferred because of the longer renal vein length in both open and laparoscopic donor nephrectomy. This facilitates implanting the kidney into the recipient. The favored use of left kidneys was especially true during the early LDN experience because of a high rate of vascular complications, such as renal vein thrombosis and graft loss in the initial attempts at right-sided LDN . Many centers in the early experience (and some currently) offered left-sided laparoscopic procedures, but obtained right kidneys in an open fashion .

At the same time that right-sided LDN was being approached cautiously, several studies demonstrated arterial and venous anomalies were not a contraindication to left-sided LDN. Lin and colleagues demonstrated that circumaortic or retro-aortic renal veins in left-sided LDN had similar surgical variables such as operative time, warm ischemia time, blood loss, and length of vessels. Likewise, Troppman and colleagues showed that multiple renal arteries in left-sided kidneys undergoing laparoscopic donation were not associated with significant changes in ischemia time or recipient function, although operative time was longer in those patients. Many laparoscopic surgeons felt that multiple left renal arteries were less problematic than obtaining a right donor kidney .

Subsequently, experience with right-sided LDN has made it an option for laparoscopic donation . Buell and colleagues reported on a multicenter review of 97 attempted right-sided LDNs. Ninety-four were completed laparoscopically with 98% graft success rate and no major complications after overcoming the initial learning curve. The authors found the same patient benefits and no increased risk of complications when compared with left-sided laparoscopic donors. Therefore, when evaluating patients for LDN, the goal to leave the best kidney with the donor patient should be applied. Typical indications to require a right-sided nephrectomy include: smaller right kidney, right renal cysts, multiple left renal arteries, left renal vein anomaly, right nephrolithiasis, and right renal artery stenosis ( Movie 1: Laparoscopic Right Donor Nephrectomy ^∗ ) (Courtesy of Iowa Hospitals & Clinics, Iowa City, IA; with permission.).

∗ Videos for this article can be accessed by visiting www.urologic.theclinics.com . In the online table of contents for this issue, click on “add-ons.”

Initial dissection (transperitoneal versus retroperitoneal)

Most institutions use a transperitoneal technique, because it provides a large working space that is familiar to the laparoscopist. The patient is placed in the modified flank position, with the planned extraction site facing upwards at approximately 70°. This allows access to both the flank and the abdomen for specimen retrieval. The patient must be supported with the assistance of an axillary roll and beanbag device cushioned with a Gelpad (Keomed Inc., Minnetonka, Minnesota). The patient is secured to the table with wide-cloth tape. All pressure points are padded. A pneumoperitoneum is achieved with Veress (Covidien, Norwalk, Connecticut) needle access for a pure-laparoscopic approach, or a hand-assistant port is placed.

A pneumoperitoneum of 12 to 15 mm Hg pressure is created. It is important to attempt to keep the pneumoperitoneum at the minimal possible working pressure, because elevated intra-abdominal pressure has been shown in animal models to decrease the renal blood flow and theoretically could decrease renal function and lead to delayed graft function . An argument against LDN is the potential for delayed graft function from the intraperitoneal pressures during the laparoscopic case. Although more recent animal studies have demonstrated no delirious effect of pneumoperitoneum on kidney function, most surgeons still attempt to keep low intraperitoneal pressure . To counteract the pneumoperitoneum, patients generally are given a large amount of intravenous crystalloids (up to 2 L/h) to maintain adequate kidney perfusion. Donors also may benefit and have less vascular compromise to the kidney if given an overnight intravenous infusion of fluids and a fluid bolus before the creation of pneumoperitoneum . Bergman and colleagues , however, recently challenged the fluid dogma and found no difference in short- or long-term graft function between aggressive (greater than 10 mL/kg/h) or conservative (less than 10 mL/kg/h) intraoperative fluid management, but this needs confirmation with a prospective study.

Ports are placed in standard laparoscopic fashion. This includes either:

• 
  

  A periumbilical hand port versus 10 mm camera port

  
  
• 
  

  A 5 (or 10) mm port in the midclavicular line two finger breaths below the costal margin

  
  
• 
  

  A 12 mm port in the lower quadrant in the midclavicular line

  
  
• 
  

  An optional 5 mm port in the anterior axillary line just above the umbilical line for assistant retraction

  
  
• 
  

  A 5 mm trocar in the midaxillary line at the umbilical level for liver retraction (right side only)

The colon is reflected medially by incising along the white line of Toldt. Wide mobilization of the colon is necessary to provide maximal exposure of the kidney and renal vessels. Proponents of a retroperitoneal approach believe that mobilization of the colon during transperitoneal surgery may risk injury to the intestine and lead to prolonged postoperative ileus . A retroperitoneal technique may lead to less ileus and shorter operative times due to not requiring colon mobilization. Ruszat and colleagues compared the retroperitoneal approach with hand-assisted, pure laparoscopy, and open techniques. The authors confirmed a lower incidence of ileus and shorter operative time for retroperitoneal approach versus the other laparoscopic techniques. Overall complications, however, were similar among the different modalities . Experience with retroperitoneal laparoscopic donor nephrectomy varies greatly between institutions and remains less used than a transperitoneal approach. Surgeons should perform the technique most likely in their hands to provide good results without complications.

Once the colon has been reflected to enter the retroperitoneal space, the gonadal vein generally is identified and followed up to the left renal vein or inferior vena cava (IVC). The renal vein should be identified and cleared of all surrounding adventitial tissue. All lumbar and other accessory veins also are identified at this time. To gain maximal length of the renal vein, the gonadal vein, lumber veins, and adrenal vein (on left) are isolated, clipped, and divided. This is especially important on right-sided donor nephrectomy to obtain maximal vein length. The artery then is identified and cleared of surrounding tissue to the junction of the aorta (on the left), or the level the artery goes posterior to the IVC (on the right).

Ureteral dissection

The ureter and its associated attachments are dissected away from the psoas muscle. Care must be taken not to compromise the vascular supply of the ureter. Careful retraction should be used, and the ureter should be grasped (only if necessary) gently with laparoscopic bowel graspers. The gonadal vein also can be mobilized without detaching it from the ureter to minimize risk of vascular compromise . The ureter is dissected down to the level of the iliac vessels.

The kidney then is mobilized completely by incising through Gerota’s fascia and dissecting it free from the surrounding perirenal fat. The kidney then is rotated anteriorly, and the posterior attachments of the renal vein and artery are completely freed to ensure maximal vessel length.

Once the dissection is completed, the ureter is clipped distally and divided to observe for adequate urine output. Most surgeons administer 12.5 g of mannitol and 20 mg of furosemide in addition to the crystalloid fluids to ensure a brisk diuresis.

Transecting the vessels

Proper handling of the vessels is a key step in LDN. Multiple variations of vessel division have been reported. The essential aspects include properly securing the vessel stump remaining with the donor, preservation of maximal arterial and venous length of the donor organ, and avoidance of vessel damage . As in a radical nephrectomy, the renal artery should be divided first. Although renal artery length is not generally the limiting factor in transplanting the organ into the recipient, care should be taken to preserve maximal length, especially on the left side. Early experience with nonlocking 10 mm titanium clips resulted in nonsufficient vessel occlusion . Animal studies confirmed that three clips needed to be placed 2.5 mm apart to secure the vessel . Obviously, this limited artery length.

Therefore, many surgeons routinely and successfully have used 10 mm Hem-o-Lok clips (Weck Closure Systems, Research Triangle Park, North Carolina) for the artery, leaving the graft end unclipped . The authors have placed two clips on the arterial stump approximately 2 mm apart, although some authors only use one clip for the arterial stump . Unfortunately, in April 2006, Teleflex Medical (the manufacturer of Hem-o-lok clips) issued a product safety warning stating that the clips were contraindicated for ligating the renal artery during LDN because of nine reported cases of severe hemorrhage from the renal hilum. The US Food and Drug Administration, however, did not issue a statement on the issue. Good data do not exist on the technique used to apply the clip or numbers of clips in these cases. The decision to continue to use this device for LDN is difficult, however, and must be discussed openly by each individual surgeon’s hospital and applied against the standard of care in the surrounding community . Most surgeons have switched to alternative forms of vascular division.

The renal vein is generally too large to undergo division with titanium clips or Hem-o-lok clips, so vascular staplers are used. The vascular staplers now also usually are employed for arterial ligation. The choice of staplers can be an Endo-TA or an Endo-GIA vascular stapler (Autosuture, Covidien, Norwalk, Connecticut). The Endo-GIA stapler can lead to a loss of 1 cm of vessel length and requires a row of staples to be removed before perfusion of the donor kidney. It is not recommended to remove the lateral rows of the Endo-GIA clips before stapling because of increased likelihood of stapler misfire . The Endo-TA stapler does not articulate and sometimes is difficult to get flush with the aorta and/or IVC. It will get additional length, however, because it does not leave a lateral row of staples. This is very important to get extra length on the right renal vein during a right LDN. The Endo-TA also has been used in conjunction with Hem-o-loc clips to get maximal occlusion of the renal artery .

Alternatively, for right-sided donors, an endoscopic Satinsky atraumatic vascular clamp (Aesculap Inc, Center Valley, PA) can be placed on the side of the caval vein, so the renal vein can be excised in full length . It is important to pay meticulous attention to any method used to transect the vessels to prevent significant intraoperative and postoperative hemorrhage. Linear stapling devices can lead to multiple complications. Primary stapler malfunction is rare (0.3% in review of donor nephrectomy stapler compli-cations), but interposition of titanium clips or improper usage leads to most failures . Friedman and colleagues reported on hemorrhagic complications of LDN and found that the use of nonlocking clips on the renal artery was associated with the most frequent and severe hemorrhages, but that locking clips and staplers also caused occasional significant hemorrhage in the postoperative period. The important point all these findings show is that the vessels should be skeletonized completely and the tips of the stapling or clipping device must be visualized clearly before engaging the instrument. Proper use will limit complications, and the surgeon should confirm correct placement of the device before activation. Although the extra confirmation time may increase warm ischemia time slightly, it may save a major hemorrhagic complication.

Kidney extraction site (hand-assisted versus pure-laparoscopic)

The site of organ extraction largely depends on the approach used for the LDN. During a retroperitoneal approach, it generally is removed through a lower quadrant incision just off the anterior superior iliac spine .

For hand-assisted laparoscopy, the kidney is removed through the hand port. Wolf and colleagues first described hand-assisted LDN in 1998. Proponents of the hand-assisted technique argue that using the already-placed hand port will decrease warm ischemia time, and the extraction incision is used better during the procedure . The hand assistance also gives the surgeon better tactile sensation for dissection, retraction, and controlling the vascular structures. Comparative studies have shown an overall decrease in operative time with the hand-assisted technique, but the operative times achieved in the comparative studies varied widely and more likely reflected the surgeons’ experience with their chosen technique .

Extraction site, however, may be a disadvantage for the hand-assisted technique and favors the pure-laparoscopic approach. In a pure-laparoscopic approach, the kidney may be extracted through an upper flank, subumbilical midline, or Pfannenstiel incision per the patient’s preference. A low transverse Pfannestiel incision is too low to perform a hand-assisted LDN through, and the hand port usually is placed in the para-umbilical region. An increased number of hernias and postoperative ileus has also been found with the hand-assisted technique, felt to be caused by more stretching of the incision during hand assistance and manipulation of the intestines with the use of the hand .

Experience with robotic-assisted LDN remains limited. One of the major concerns is anticipated increased warm ischemia time and difficulty removing the specimen with the robotic platform docked. The kidney usually is removed through a low midline incision with the robotic technique. One of the largest published series on robotic LDN reports using a hand-assist port from the beginning of the case in the low midline, which allows for specimen extraction at the conclusion of the case .

Regardless of the approach, all attempts should be made to limit warm ischemia time. Prolonged warm ischemia has been criticized as a risk factor during LDN. Early experience with the pure laparoscopic technique involved placing the specimen in an extraction bag and then removing the specimen. The kidney therefore was detached from its blood supply, placed in a bag, and then removed. Several reports of bag breakage and difficult entrapment led to occasional prolonged warm ischemia times . Therefore, many authors use a technique described by Shalhav and colleagues during pure LDN. The technique also addresses important points that can be used with retroperitoneal, robotic, or hand-assisted extraction. The technique involves placing an assistant’s hand through a small Pfannenstiel incision (to maintain pneumoperitoneum) before dividing the vessels. The kidney is secured by the assistant’s hand, and the ureter is retracted away from the vessels. Once the hilum is confirmed to be free of surrounding tissue and ready to divide, the artery and vein are divided, hemostasis confirmed, and the kidney is removed quickly by the assistant and passed off the back table. With this technique, Shalhav demonstrated a significant decrease in warm ischemia time (101 seconds versus 173 seconds; P <.001). The key features are the ability to perform a desirable low Pfannenstiel incision and complete control of the donor kidney during the crucial steps of vessel division and retrieval.

Initial dissection (transperitoneal versus retroperitoneal)

Most institutions use a transperitoneal technique, because it provides a large working space that is familiar to the laparoscopist. The patient is placed in the modified flank position, with the planned extraction site facing upwards at approximately 70°. This allows access to both the flank and the abdomen for specimen retrieval. The patient must be supported with the assistance of an axillary roll and beanbag device cushioned with a Gelpad (Keomed Inc., Minnetonka, Minnesota). The patient is secured to the table with wide-cloth tape. All pressure points are padded. A pneumoperitoneum is achieved with Veress (Covidien, Norwalk, Connecticut) needle access for a pure-laparoscopic approach, or a hand-assistant port is placed.

A pneumoperitoneum of 12 to 15 mm Hg pressure is created. It is important to attempt to keep the pneumoperitoneum at the minimal possible working pressure, because elevated intra-abdominal pressure has been shown in animal models to decrease the renal blood flow and theoretically could decrease renal function and lead to delayed graft function . An argument against LDN is the potential for delayed graft function from the intraperitoneal pressures during the laparoscopic case. Although more recent animal studies have demonstrated no delirious effect of pneumoperitoneum on kidney function, most surgeons still attempt to keep low intraperitoneal pressure . To counteract the pneumoperitoneum, patients generally are given a large amount of intravenous crystalloids (up to 2 L/h) to maintain adequate kidney perfusion. Donors also may benefit and have less vascular compromise to the kidney if given an overnight intravenous infusion of fluids and a fluid bolus before the creation of pneumoperitoneum . Bergman and colleagues , however, recently challenged the fluid dogma and found no difference in short- or long-term graft function between aggressive (greater than 10 mL/kg/h) or conservative (less than 10 mL/kg/h) intraoperative fluid management, but this needs confirmation with a prospective study.

Ports are placed in standard laparoscopic fashion. This includes either:

• 
  

  A periumbilical hand port versus 10 mm camera port

  
  
• 
  

  A 5 (or 10) mm port in the midclavicular line two finger breaths below the costal margin

  
  
• 
  

  A 12 mm port in the lower quadrant in the midclavicular line

  
  
• 
  

  An optional 5 mm port in the anterior axillary line just above the umbilical line for assistant retraction

  
  
• 
  

  A 5 mm trocar in the midaxillary line at the umbilical level for liver retraction (right side only)

The colon is reflected medially by incising along the white line of Toldt. Wide mobilization of the colon is necessary to provide maximal exposure of the kidney and renal vessels. Proponents of a retroperitoneal approach believe that mobilization of the colon during transperitoneal surgery may risk injury to the intestine and lead to prolonged postoperative ileus . A retroperitoneal technique may lead to less ileus and shorter operative times due to not requiring colon mobilization. Ruszat and colleagues compared the retroperitoneal approach with hand-assisted, pure laparoscopy, and open techniques. The authors confirmed a lower incidence of ileus and shorter operative time for retroperitoneal approach versus the other laparoscopic techniques. Overall complications, however, were similar among the different modalities . Experience with retroperitoneal laparoscopic donor nephrectomy varies greatly between institutions and remains less used than a transperitoneal approach. Surgeons should perform the technique most likely in their hands to provide good results without complications.

Once the colon has been reflected to enter the retroperitoneal space, the gonadal vein generally is identified and followed up to the left renal vein or inferior vena cava (IVC). The renal vein should be identified and cleared of all surrounding adventitial tissue. All lumbar and other accessory veins also are identified at this time. To gain maximal length of the renal vein, the gonadal vein, lumber veins, and adrenal vein (on left) are isolated, clipped, and divided. This is especially important on right-sided donor nephrectomy to obtain maximal vein length. The artery then is identified and cleared of surrounding tissue to the junction of the aorta (on the left), or the level the artery goes posterior to the IVC (on the right).

Ureteral dissection

The ureter and its associated attachments are dissected away from the psoas muscle. Care must be taken not to compromise the vascular supply of the ureter. Careful retraction should be used, and the ureter should be grasped (only if necessary) gently with laparoscopic bowel graspers. The gonadal vein also can be mobilized without detaching it from the ureter to minimize risk of vascular compromise . The ureter is dissected down to the level of the iliac vessels.

The kidney then is mobilized completely by incising through Gerota’s fascia and dissecting it free from the surrounding perirenal fat. The kidney then is rotated anteriorly, and the posterior attachments of the renal vein and artery are completely freed to ensure maximal vessel length.

Once the dissection is completed, the ureter is clipped distally and divided to observe for adequate urine output. Most surgeons administer 12.5 g of mannitol and 20 mg of furosemide in addition to the crystalloid fluids to ensure a brisk diuresis.

Transecting the vessels

Proper handling of the vessels is a key step in LDN. Multiple variations of vessel division have been reported. The essential aspects include properly securing the vessel stump remaining with the donor, preservation of maximal arterial and venous length of the donor organ, and avoidance of vessel damage . As in a radical nephrectomy, the renal artery should be divided first. Although renal artery length is not generally the limiting factor in transplanting the organ into the recipient, care should be taken to preserve maximal length, especially on the left side. Early experience with nonlocking 10 mm titanium clips resulted in nonsufficient vessel occlusion . Animal studies confirmed that three clips needed to be placed 2.5 mm apart to secure the vessel . Obviously, this limited artery length.

Therefore, many surgeons routinely and successfully have used 10 mm Hem-o-Lok clips (Weck Closure Systems, Research Triangle Park, North Carolina) for the artery, leaving the graft end unclipped . The authors have placed two clips on the arterial stump approximately 2 mm apart, although some authors only use one clip for the arterial stump . Unfortunately, in April 2006, Teleflex Medical (the manufacturer of Hem-o-lok clips) issued a product safety warning stating that the clips were contraindicated for ligating the renal artery during LDN because of nine reported cases of severe hemorrhage from the renal hilum. The US Food and Drug Administration, however, did not issue a statement on the issue. Good data do not exist on the technique used to apply the clip or numbers of clips in these cases. The decision to continue to use this device for LDN is difficult, however, and must be discussed openly by each individual surgeon’s hospital and applied against the standard of care in the surrounding community . Most surgeons have switched to alternative forms of vascular division.

The renal vein is generally too large to undergo division with titanium clips or Hem-o-lok clips, so vascular staplers are used. The vascular staplers now also usually are employed for arterial ligation. The choice of staplers can be an Endo-TA or an Endo-GIA vascular stapler (Autosuture, Covidien, Norwalk, Connecticut). The Endo-GIA stapler can lead to a loss of 1 cm of vessel length and requires a row of staples to be removed before perfusion of the donor kidney. It is not recommended to remove the lateral rows of the Endo-GIA clips before stapling because of increased likelihood of stapler misfire . The Endo-TA stapler does not articulate and sometimes is difficult to get flush with the aorta and/or IVC. It will get additional length, however, because it does not leave a lateral row of staples. This is very important to get extra length on the right renal vein during a right LDN. The Endo-TA also has been used in conjunction with Hem-o-loc clips to get maximal occlusion of the renal artery .

Alternatively, for right-sided donors, an endoscopic Satinsky atraumatic vascular clamp (Aesculap Inc, Center Valley, PA) can be placed on the side of the caval vein, so the renal vein can be excised in full length . It is important to pay meticulous attention to any method used to transect the vessels to prevent significant intraoperative and postoperative hemorrhage. Linear stapling devices can lead to multiple complications. Primary stapler malfunction is rare (0.3% in review of donor nephrectomy stapler compli-cations), but interposition of titanium clips or improper usage leads to most failures . Friedman and colleagues reported on hemorrhagic complications of LDN and found that the use of nonlocking clips on the renal artery was associated with the most frequent and severe hemorrhages, but that locking clips and staplers also caused occasional significant hemorrhage in the postoperative period. The important point all these findings show is that the vessels should be skeletonized completely and the tips of the stapling or clipping device must be visualized clearly before engaging the instrument. Proper use will limit complications, and the surgeon should confirm correct placement of the device before activation. Although the extra confirmation time may increase warm ischemia time slightly, it may save a major hemorrhagic complication.

Kidney extraction site (hand-assisted versus pure-laparoscopic)

The site of organ extraction largely depends on the approach used for the LDN. During a retroperitoneal approach, it generally is removed through a lower quadrant incision just off the anterior superior iliac spine .

For hand-assisted laparoscopy, the kidney is removed through the hand port. Wolf and colleagues first described hand-assisted LDN in 1998. Proponents of the hand-assisted technique argue that using the already-placed hand port will decrease warm ischemia time, and the extraction incision is used better during the procedure . The hand assistance also gives the surgeon better tactile sensation for dissection, retraction, and controlling the vascular structures. Comparative studies have shown an overall decrease in operative time with the hand-assisted technique, but the operative times achieved in the comparative studies varied widely and more likely reflected the surgeons’ experience with their chosen technique .

Extraction site, however, may be a disadvantage for the hand-assisted technique and favors the pure-laparoscopic approach. In a pure-laparoscopic approach, the kidney may be extracted through an upper flank, subumbilical midline, or Pfannenstiel incision per the patient’s preference. A low transverse Pfannestiel incision is too low to perform a hand-assisted LDN through, and the hand port usually is placed in the para-umbilical region. An increased number of hernias and postoperative ileus has also been found with the hand-assisted technique, felt to be caused by more stretching of the incision during hand assistance and manipulation of the intestines with the use of the hand .

Experience with robotic-assisted LDN remains limited. One of the major concerns is anticipated increased warm ischemia time and difficulty removing the specimen with the robotic platform docked. The kidney usually is removed through a low midline incision with the robotic technique. One of the largest published series on robotic LDN reports using a hand-assist port from the beginning of the case in the low midline, which allows for specimen extraction at the conclusion of the case .

Regardless of the approach, all attempts should be made to limit warm ischemia time. Prolonged warm ischemia has been criticized as a risk factor during LDN. Early experience with the pure laparoscopic technique involved placing the specimen in an extraction bag and then removing the specimen. The kidney therefore was detached from its blood supply, placed in a bag, and then removed. Several reports of bag breakage and difficult entrapment led to occasional prolonged warm ischemia times . Therefore, many authors use a technique described by Shalhav and colleagues during pure LDN. The technique also addresses important points that can be used with retroperitoneal, robotic, or hand-assisted extraction. The technique involves placing an assistant’s hand through a small Pfannenstiel incision (to maintain pneumoperitoneum) before dividing the vessels. The kidney is secured by the assistant’s hand, and the ureter is retracted away from the vessels. Once the hilum is confirmed to be free of surrounding tissue and ready to divide, the artery and vein are divided, hemostasis confirmed, and the kidney is removed quickly by the assistant and passed off the back table. With this technique, Shalhav demonstrated a significant decrease in warm ischemia time (101 seconds versus 173 seconds; P <.001). The key features are the ability to perform a desirable low Pfannenstiel incision and complete control of the donor kidney during the crucial steps of vessel division and retrieval.