Deceased Donor Nephrectomy
Deceased donor renal donation predominates as the source of transplantable kidneys. In the US, deceased donors provide approximately 13,000 kidneys per year or 70% of the available pool of transplantable kidneys ( Fig. 8.1 ).
Recent years have seen an increase in the number of deceased donors secondary to the opioid crisis in North American (and Europe) and the resultant number of referrals for organ donation. Despite assumptions that these donors would be predominantly younger and without comorbidities, data support growth in all age categories and this growth in donor population has been associated with extensive medical and substance abuse histories. Anoxic brain injury is the primary mechanism of terminal injury in these donors and this can be accompanied by significant hypotensive periods before resuscitation. Such an insult can frequently manifest itself as acute kidney injury at the time of donation.
Deceased donors are divided into subgroups of donation after brain death (DBD) and donation after circulatory death (DCD). DBD donors are pronounced dead by both clinical and radiologic evaluations that are clearly defined. The operations from these donors are conducted in controlled settings with careful physiologic monitoring to ensure optimal organ perfusion and oxygenation until perfusion and cooling of donor organs. DBD donors account for the overwhelming majority of deceased donors representing 82.3% of donors in 2015. DCD donation rates have increased over the past decade, and the proportion of DCD donors contributing to the donor pool more than doubled from 7.3% to 17.7% between 2005 and 2015 ( Fig. 8.2 ). Other countries have higher rates of DCD donation, for example, in the UK in 2017 to 2018, 40% of all deceased donors were DCD ( https://nhsbtdbe.blob.core.windows.net/umbraco-assets-corp/11628/transplant-activity-report-2017-2018.pdf ).
The US introduced a new deceased donor renal transplant allocation system in 2013. This system was designed to match donor kidneys with recipients who would receive the maximal benefit in terms of life years. In essence, donor kidneys are evaluated for quality using the Kidney Donor Risk Index (KDRI; see Fig.8.2 ). Donor-specific factors from the KDRI (including age, ethnicity, height, weight, history of hypertension or diabetes, hepatitis C status, and donation after cardiac death status) are used to create a Kidney Donor Profile Index that assigns a score between 0 and 100, setting the median donor as the 50th percentile. A kidney with a lower perceived risk (and likely of higher quality) scores lower. Recipients are likewise risk stratified for expected posttransplant survival (EPTS) using age, history of diabetes, duration of dialysis, and history of prior transplant. The lowest 20th percentile kidneys (which are expected to have the longest graft survival) are allocated preferentially to recipients in the highest 20th percentile of expected survival (who are expected to have the longest patient survival). The new system also offers priority allocation to highly sensitized recipients, with patients having a calculated panel reactive antibody (cPRA) ≥99 receiving the greatest benefit, but also increasing access for patients with a cPRA ≥98%. Zero-antigen mismatch donors will still be offered priority under the new system. Recipients are still offered points based on years on the waiting list (or maintenance dialysis), prior living donation, degree of sensitization, and one degree of HLA mismatch).
Donation After Brain Death
Kidneys from DBD donors are usually recovered in conjunction with recovery of other abdominal and thoracic organs and require coordination of the surgical teams performing different roles. Often, thoracic teams will have complicated recipients with redo-transplantation, mechanical support devices, or other complicated histories, and this can result in significant delays until cross-clamp for abdominal recovery teams.
Initial midline laparotomy, and isolation and control of the infrarenal abdominal aorta is accomplished. In cases where the liver is recovered, isolation of either the inferior mesenteric vein or portal vein can also be achieved. The aorta is cannulated after administering heparin, and in appropriate cases venous cannulation is performed. In coordination with thoracic recovery, perfusion is initiated, the aorta is clamped in a supraceliac location, and either the inferior vena cava or the right atrium are transected and suction or drainage devices are placed to facilitate perfusion. The abdominal organs are packed with ice for cooling while flushing and recovery of other organs are performed. Mobilization of the ascending and descending colon can be performed to allow for more direct exposure of the kidneys to ice. Recovery of thoracic organs, liver, and pancreas generally precedes recovery of the kidneys ( Fig. 8.3 ).
Recovery of the kidneys can be performed either individually or en bloc . Individual recovery of the kidneys is performed by transecting the left renal vein at the vena cava. The aorta and vena cava can both be transected superior to the level of cannulation (usually just superior to bifurcation) and at the origin of the superior mesenteric artery (SMA) and superior to the right renal vein. Division of the aorta should be performed by incising the base of the SMA and, with an oblique angle, entering the aorta superiorly to identify renal arteries because they often enter at this level or higher. Superior transaction of the aorta should be performed ideally to preserve a Carrel patch on both the right and left renal arteries. The right renal vein should be identified before transaction of the vena cava to preserve a superior cuff that can be used to construct a venous extension when necessary.
Individual recovery starts with either side by isolating the ureter and gonadal vein and transecting distally. Care should be taken to leave tissue around the ureter with sharp dissection to minimize the risk of devascularizing the ureter by stripping it of adjacent tissues. The anterior wall of the aorta can be longitudinally sharply transected, followed by division of the posterior wall, with care taken to identify single or multiple renal arteries and leave sufficient tissue for Carrel patches around each vessel. From an inferior approach, working from the midline and posterior to the aorta, all tissues can be sharply divided with attention to the location of the ureter to avoid inadvertent injury. Working both superiorly and laterally, the vasculature and kidneys can be separated from the lateral abdominal and retroperitoneal attachments. Posterior dissection proceeding directly against the psoas muscle will minimize the risk of injuring renal arteries. Regardless of extent, Gerota’s fascia should be removed with the kidneys to be separated at later time. The right kidney should be removed with all remaining vena cava to preserve the conduit for venous extension grafts when necessary.
En bloc recovery of the kidneys is performed without longitudinal transection of the aorta or division of the renal vein. Inferior to superior dissection is performed posterior to the aorta and vena cava, and with initial isolation of the ureters to avoid injury. Separation of the kidneys is then performed after removal with the similar goals of leaving an aortic cuff for all renal arteries and the vena cava with the right kidney.
Local procurement centers have preferences for marking the ureters with ligature or other labeling to identify right versus left kidneys.
If concerns exist for the quality of perfusion based on the appearance of the kidneys, direct cannulation and perfusion of the right and left renal arteries can be performed on the back table. Although this step is not usually necessary, concern regarding poor perfusion or the mottled appearance of the kidneys should direct additional flushing.
Donation After Circulatory Death
Whereas in total numbers DBD donors account for the vast majority of recovered and transplanted kidneys, DCD has become an increasingly common source of deceased donor kidneys in recent years. In the US in 2015, DCD donors provided more than 2000 donor kidneys (nearly 20% of the total deceased donation). DCD donors yielded more kidneys per donor (1.56) than brain dead donors (1.44).
Recovery of kidneys from DCD donors is performed in a similar manner to brain dead donors with a few modifications. Individual hospitals and organ procurement organizations (OPOs) set specific guidelines for time limits for recovery to be performed after withdrawal of life support that vary between 60 and 120 minutes. These waiting periods occur either in a perioperative setting or in the operating room; outside the US, this time may extend to 180 to 240 minutes. According to local practice, patients are declared deceased after cessation of pulse, cardiac rhythm, or electrical activity. The cessation of all pulseless electrical activity (PEA) has not been deemed necessary as a criterion for declaration in the absence of pulse pressure. An additional waiting period between 2 and 5 minutes occurs before initiation of organ recovery.
The period of warm ischemic time between withdrawal of life support and the initiation of cooling and perfusion with organ preservation solutions contributes to the increased rates of delayed graft function and organ dysfunction seen with DCD organs. Thus the surgical procedure needs to be performed in an expedited fashion to cool and perfuse organs as soon as possible. A midline incision from sternal notch to pubis is rapidly performed and, using combinations of sharp and blunt dissection, the abdominal cavity is entered and the distal aorta is cannulated with a perfusion catheter with or without isolated control. Immediate perfusion should commence at this point. Transection of the distal inferior vena cava and placement of drainage device or suction catheter can be performed to facilitate perfusion. Depending on recovery of the liver or thoracic organs, the aorta can be clamped at the level of the descending thoracic aorta after opening the chest. DCD recoveries for kidneys alone can avoid opening the chest, and clamping of the aorta should occur at the supraceliac level. The abdominal cavity should then be packed with ice during perfusion. A rapid surgical technique designed to minimize the time taken to achieve cross-clamp and explant of the organs from the abdominal cavity, and facilitate organ cooling may improve renal outcomes as has been reported with other organs.
While infusion of the preservation solution is underway, surgical recovery of the kidneys can be performed with a similar technique to recovery in DBD donors. Whereas an expedient technique is important, precision remains paramount in these circumstances to prevent the higher rates of surgical damage and organ discard that have been reported. After removal of the kidneys from the abdominal cavity, additional perfusion can be performed once the kidneys are in cold solution depending on either preference or concerns regarding the quality of intraabdominal perfusion. Modified technical approaches including balloon catheter placement for in situ preservation or use of extracorporeal support after death have not achieved substantial effect in improving results. Although supportive data exist regarding the ability of hypothermic pulsatile perfusion to improve outcomes for DCD kidneys, conflicting data still exist and thus this conclusion is not uniform.
Additional interest in normothermic perfusion devices has been generated in recent years. Although no definitive conclusions can be reached, potential for improved function and decreased rates of DGF are under investigation. Although a variety of strategies have been proposed, including initiating normothermic perfusion in situ, ex vivo at the donor hospital, or on return to the recipient center, a single system that has reliably improved outcomes has yet to be reported.
Living Donor Nephrectomy
Living renal donation provides an invaluable resource in regard to both organ quantity and quality. There are 5600 living kidney donations annually in the US, which accounts for approximately 30% of annual US renal transplant volume. The absolute number of living donors nearly equals the number of deceased donors and thus remains critical as a source of transplantable organs. Living donor kidneys are of superior quality in every objective measurement including immediate graft function rates, graft half-life, and life years gained for recipients. The available pool of donors has remained relatively stable over the recent decade, although demographics have demonstrated increases in donors over 50 years old (29.5%) and women (63.5%; Fig. 8.4 ). The primary responsibility of the donor surgeon is patient safety, and this overarching concern must guide every pre-, intra-, and postoperative decision. The reliably safe outcomes with donor nephrectomy and good long-term renal function of donors are paramount to preserve the justification for removing a kidney from a healthy donor.
As the transplant community has continued to gain experience caring for living donors, conditions that had previously served as absolute or relative contraindications to living donation are being reconsidered. Select centers now accept donors with prior surgical histories that affect the technical complexity of the operation. These include prior histories of bariatric procedures, gynecologic operations, hernia repair, appendectomy, and cholecystectomy. Although not contraindications for surgery, these procedures may predict a more complicated technical operation. Anatomic variants that once precluded donation, such as multiple renal arteries and circum- or retroaortic renal veins, no longer eliminate potential donors at many centers. These more complicated patients may be eligible for renal donation, and consideration should be given for referral to centers with experience in these conditions.
Anesthetic Management
Communication with anesthesia personnel is important to ensure that good urine output is achieved throughout the case. Pneumoperitoneum has been demonstrated to impair venous return influencing renal perfusion, and volume expansion has been demonstrated as the primary intervention to counteract this effect. Patients often require greater than 5 L of crystalloid to achieve a robust urine output. Mannitol can be administered in divided doses of 12.5 g to augment urine output. Urine output should be monitored and low output addressed aggressively by administering additional intravenous fluids and decreasing or eliminating pneumoperitoneum until adequate urine output is achieved.
Whereas inadequate volume resuscitation is the most likely factor, identifying other confounding factors for low urine output, including relative hypotension, inability to tolerate pneumoperitoneum, or other physiologic events are important to determine whether the case should proceed. Although extremely unusual, our practice is not to proceed with donation if adequate urine output cannot be achieved.
Adequate relaxation is necessary to achieve sufficient pneumoperitoneum to provide abdominal domain to perform surgery. Diminishing abdominal domain will result from patients that are inadequately paralyzed and will result in difficulty making surgical progress. This may be realized at midpoints of the case as initial paralytic agents may require redosing. Participation by experienced anesthesiologists is important throughout the procedure, but especially immediately before division of vascular structures.
We do not routinely administer heparin before division of the renal vessels and have not observed complications from this practice. Some surgeons administer low-dose intravenous heparin (3000 units) before vascular division with reversal by administering protamine after removal of the kidney.
Regardless of the technical approach, control of postoperative pain should be initiated during the operative case. Intraoperative administration of narcotics provides transient pain control. The use of local anesthetics and systemic nonsteroidal agents can minimize postoperative pain and narcotic requirements. We routinely inject 0.5% liposomal bupivacaine into port and extraction sites and consider the use of intravenous ketorolac for most patients. The use of liposomal bupivacaine preparations has added to the duration of local anesthesia for up to 72 hours and we have found this useful to facilitate early postoperative pain control and discharge. Additionally, initiating regularly scheduled oral narcotics soon after surgery can prevent intense pain spikes as local agents diminish.
Open Donor Nephrectomy
Open donor nephrectomy has been nearly completely replaced by minimally invasive surgical techniques. In fact, surgeons trained in recent eras may have little or no experience with standard open or miniopen techniques. Nonetheless, these techniques may be employed by select centers and/or surgeons based on indication or preference. Relative indications may include the presence of complicated vascular anatomy, prior operations that complicate laparoscopic approaches, or right nephrectomy. Whereas these techniques deserve an appropriate place in the arsenal of living donor nephrectomy, laparoscopic techniques can be successfully used in almost all cases. Despite reduced invasiveness of miniopen incisions, laparoscopic techniques still result in comparatively decreased pain, faster return to work, and higher patient satisfaction.
Standard open techniques depend on the division of muscle and possible rib resection compared with miniopen approaches that are muscle-sparing and avoid rib resection. The miniopen techniques have been reported to improve donor outcomes compared with standard open techniques. After the induction of general anesthesia, patients are positioned in a flexed lateral decubitus orientation on the operative table. The patient is prepped and draped from the inferior rib margin to the superior iliac crest. A lateral oblique incision is performed inferior to the 12th rib with division or separation of the oblique and transverse musculature. Segmental resection of the inferior rib may be necessary to improve exposure of the upper pole of the kidney. Combinations of manual and electrocautery dissection are performed around Gerota’s fascia to permit retractor placement. The peritoneal cavity is swept anteromedially as planes are created to the level of the renal vein and artery. Retractors can be placed either on fixated platforms or by handheld techniques. Retroperitoneal dissection continues around the kidney and inferiorly to identify and isolate the ureter and gonadal vessels. The ureter should be dissected close to the level of the iliac vessels to ensure adequate length. Complete mobilization of the kidney is performed, and the artery and vein are isolated at their origin and insertion in the aorta and vena cava, respectively. The adrenal gland can be separated from the parenchyma of the kidney lateral to medial. The adrenal vein on the left side may be divided between ligatures or clips to maximize renal vein length. Lumbar veins posterior to the renal vein should be divided to also maximize renal vein length. This can be performed between vascular clamps, surgical clips, or stapling devices. After complete isolation of the vascular pedicle, division of the ureter and renal vessels proceeds. The ureter and gonadal vein are divided distally with ligatures, clips, or stapling devices. The renal artery or arteries are then divided. This can be performed by ligation with or without suture or stapling device. Finally, the renal vein can be divided with a similar technique. Vascular clamps can be used to maximize vessel length with subsequent ligation and suturing of vessels after removal of the kidney. The presence of multiple vessels requires planning for the order of division. Placement of multiple vascular clamps may prove difficult with limited space, thus stapling devices may be preferred. Transfixing techniques with either sutures or staples should be used for the renal artery and vein stumps to minimize bleeding risk.
Inspection for good hemostasis with or without placement of hemostatic adjuncts is then performed. Abdominal wall closure is performed in multiple layers and with preference for absorbable suture. Local anesthetic can be injected to provide local pain control and minimize systemic requirements. Similarly, intravenous nonsteroidal antiinflammatory drugs may be used to provide pain relief and minimize narcotic requirements. These should be discontinued within 48 hours. Postoperatively, patients can receive intravenous and oral narcotics and can return to normal diet and activity.
Laparoscopic Donor Nephrectomy
Initial reports were made of a laparoscopic approach to nephrectomy for tumor with morcellation and extraction in 1991. In 1995 this approach had been successfully applied to living donor nephrectomy as Ratner made the first report of laparoscopic nephrectomy for transplantation with immediate graft function. Initial comparisons of open and laparoscopic approaches reported substantial improvements in donor recovery. These donor benefits were confirmed in subsequent studies. A recent randomized controlled trial demonstrated improved donor satisfaction, less morbidity, and equivalent graft outcomes. Early large series reported concerns regarding complications, especially with regard to the ureter, associated with the laparoscopic technique. These decreased as progressive technical experience was achieved. The improved patient recovery and minimally invasive approach has permitted discharge for select patients on the first postoperative day. Additionally, the advent of laparoscopic donor nephrectomy was associated with increased living donation rates and overall volumes, providing important recipient benefits.
In the US in 2015, 97% of living donor nephrectomies were performed by a laparoscopic approach, with a majority performed with a hand-assisted approach ( Fig. 8.5 ). The number of cases performed via an open approach has continued to decrease over the past 5 years with 3% of donor nephrectomies performed via an open retroperitoneal or transabdominal approach.
