Residency · Residency · Urology
Surgical Anatomy and Technique of Renal Transplantation
Introduction
Renal transplantation is the preferred treatment for patients with end-stage renal disease (ESRD), as it provides superior survival rates and quality of life compared to dialysis. In the United States, over 25,000 kidney transplants are performed annually. Urologists play a pivotal role throughout the transplantation process, including donor nephrectomy, bench preparation of the allograft, and the recipient transplant operation. A thorough understanding of the vascular anatomy, surgical techniques, and ureteral reimplantation methods is essential for urology residents involved in this complex procedure.
Indications and Contraindications
Indications
Renal transplantation is indicated for patients with ESRD, typically defined by an estimated glomerular filtration rate (eGFR) below 20 mL/min or those already on dialysis, regardless of the underlying cause. Preemptive transplantation, performed before the initiation of dialysis, is associated with the best outcomes. The most common causes of ESRD include diabetes mellitus, accounting for approximately 40% of cases, hypertension at 28%, glomerulonephritis at 10%, and polycystic kidney disease at 5%.
Absolute Contraindications
Certain conditions preclude transplantation due to unacceptable risks. Active malignancy is an absolute contraindication, with disease-free interval requirements varying depending on the cancer type. Active, uncontrolled infections such as untreated HIV, hepatitis, or tuberculosis also disqualify candidates. Severe, uncorrectable cardiac disease poses prohibitive surgical risk. Active substance abuse or non-adherence to medical therapy undermines transplant success. Finally, patients with a limited life expectancy of less than two years from non-renal diseases are generally excluded.
Relative Contraindications
Some factors require individualized evaluation rather than outright exclusion. Advanced age, typically over 70 to 75 years, is considered on a case-by-case basis. Obesity, particularly with a body mass index (BMI) greater than 40, increases the risk of surgical complications. Additionally, recurrent primary diseases that are likely to destroy the graft, such as focal segmental glomerulosclerosis or oxalosis, represent relative contraindications.
Donor Sources
Living Donors
Living donor kidneys offer superior outcomes, with one-year graft survival rates of 97-98% and graft half-lives of 15 to 20 years. The standard approach for donor nephrectomy is laparoscopic, with the left kidney preferred due to its longer renal vein, which facilitates venous anastomosis. Donors must have normal bilateral kidney function, no proteinuria, no uncontrolled hypertension, and compatible anatomy. Advances in desensitization protocols have made ABO-incompatible and HLA-incompatible transplantations feasible.
Deceased Donors
Deceased donor kidneys come from several categories. Standard criteria donors (SCD) are brain-dead donors with normal kidney function. Expanded criteria donors (ECD), or those with a kidney donor profile index (KDPI) greater than 85%, are typically older or have comorbidities; while graft survival is inferior compared to SCD, it remains acceptable. Donation after circulatory death (DCD) kidneys have a higher rate of delayed graft function but achieve comparable long-term outcomes when cold ischemia is properly managed. Cold ischemia time (CIT) should be kept under 24 hours for SCD and under 18 hours for ECD, as prolonged CIT increases the risk of delayed graft function and reduces graft survival. Machine perfusion, either hypothermic or normothermic, improves outcomes for marginal donor kidneys by reducing delayed graft function.
Surgical Anatomy
Recipient Iliac Fossa
The transplanted kidney is placed extraperitoneally in the iliac fossa, typically on the right side for the first transplant. The right side is preferred because the external iliac vein is more superficial and accessible. For retransplantation, the left iliac fossa is usually chosen. Vascular anastomoses involve connecting the renal artery to the external iliac artery in an end-to-side fashion or, less commonly, to the internal iliac artery end-to-end. The renal vein is anastomosed end-to-side to the external iliac vein. Ureteral reimplantation is performed via ureteroneocystostomy into the native bladder.
Allograft Vascular Anatomy
Most kidneys (70-75%) have a single renal artery, which is ideal for transplantation. However, 25-30% have multiple renal arteries, necessitating bench reconstruction techniques such as conjoined anastomosis, separate reimplantation, or the use of a Carrel patch. The renal vein is usually single on the right side, while the left renal vein is longer, crossing anterior to the aorta and receiving tributaries from the gonadal and adrenal veins. The Carrel patch, an aortic cuff surrounding the renal artery ostium, is used with deceased donor kidneys to simplify arterial anastomosis.
<image>Surgical anatomy diagram of the recipient iliac fossa showing the transplant kidney positioned extraperitoneally with labeled vascular anastomoses: renal artery to external iliac artery (end-to-side with Carrel patch), renal vein to external iliac vein (end-to-side), and the ureter coursing to the bladder for Lich-Gregoir ureteroneocystostomy, with the native kidneys left in situ and labeled iliac vessels, spermatic cord/round ligament retracted, and peritoneum reflected medially</image>
Recipient Operative Technique
Preparation
Preoperative dialysis is performed if the patient is hyperkalemic (potassium >5.5 mEq/L) or volume-overloaded. Immunosuppression induction, typically with agents such as basiliximab or antithymocyte globulin, is administered preoperatively or intraoperatively. Antibiotic prophylaxis, usually cefazolin or per institutional protocol, is given. A Foley catheter is placed with bladder irrigation and partial filling to facilitate ureteroneocystostomy.
Incision and Exposure
The surgical approach involves a curvilinear Gibson incision or a hockey-stick incision in the ipsilateral lower quadrant. The extraperitoneal space is accessed by reflecting the peritoneum medially. The external iliac artery and vein are exposed, and lymphatics overlying these vessels are ligated and divided to prevent postoperative lymphocele formation. The spermatic cord or round ligament is retracted for better visualization.
Bench Preparation of the Allograft
Bench preparation is performed on ice in a basin of cold preservation solution. Perirenal fat is removed while preserving the renal capsule and hilar fat. All branches such as adrenal, gonadal, and lumbar veins are identified and ligated. Multiple arteries, if present, are reconstructed using techniques like conjoined cuffs, separate Carrel patches, or microsurgical anastomosis on the back table. The kidney is flushed with cold preservation solutions such as University of Wisconsin (UW) solution, histidine-tryptophan-ketoglutarate (HTK) solution, or machine perfusate.
Vascular Anastomosis
The renal vein is anastomosed first to establish venous outflow before arterial inflow, minimizing warm ischemia-reperfusion injury. This is done end-to-side to the external iliac vein using continuous 5-0 or 6-0 Prolene sutures. The renal artery is then anastomosed end-to-side to the external iliac artery with continuous or interrupted 5-0 or 6-0 Prolene. If a Carrel patch is present, the patch is anastomosed to the iliac artery. Alternatively, an end-to-end anastomosis to the internal iliac artery may be performed, though this is less common and may compromise pelvic blood flow. Reperfusion is initiated by releasing the venous clamp first, followed by the arterial clamp, allowing observation of even reperfusion and turgor. Surface bleeding from capsular vessels indicates good perfusion. Warm ischemia time, defined as the interval from removal of cold preservation to reperfusion, should be kept under 30 to 45 minutes.
Ureteroneocystostomy
The most commonly used technique for ureteral reimplantation is the Lich-Gregoir extravesical method. This involves a 2 to 3 cm detrusorotomy incision on the anterolateral bladder wall, followed by a small mucosotomy. The distal ureter is spatulated and anastomosed to the bladder mucosa with interrupted 5-0 absorbable sutures over a double-J ureteral stent. The detrusor muscle is then closed over the ureter to create a submucosal anti-reflux tunnel. An alternative technique is the Politano-Leadbetter transvesical approach, which requires cystotomy and creation of a submucosal tunnel intravesically. The double-J ureteral stent is typically left in place for 4 to 6 weeks to protect the anastomosis and reduce the risk of urine leak.
<image>Step-by-step illustration of the Lich-Gregoir ureteroneocystostomy technique: (1) detrusorotomy exposing the bladder mucosa on the anterolateral bladder surface, (2) mucosotomy and spatulation of the donor ureter, (3) anastomosis of the spatulated ureter to the bladder mucosa over a double-J stent with interrupted absorbable sutures, and (4) closure of the detrusor muscle over the ureter to create the anti-reflux tunnel</image>
Postoperative Management
Immediate Postoperative
Postoperatively, urine output is closely monitored. Brisk diuresis of 200 to 500 mL per hour is expected, especially following living donor transplantation. Delayed graft function (DGF), defined as the need for dialysis within seven days of transplant, occurs more frequently with deceased donor kidneys (20-30%) and prolonged cold ischemia time. Fluid replacement is generally managed by replacing urine output milliliter-for-milliliter with half-normal saline during the first 24 to 48 hours, avoiding dehydration and hypovolemia. A duplex ultrasound is performed on postoperative day one to assess allograft perfusion, resistive indices, and detect perinephric fluid collections.
Immunosuppression
Induction immunosuppression typically involves anti-IL-2 receptor antibodies such as basiliximab or antithymocyte globulin for high-immunologic-risk patients. Maintenance therapy consists of triple drug regimens including a calcineurin inhibitor (usually tacrolimus), an antimetabolite (mycophenolate mofetil), and corticosteroids. Tacrolimus trough levels vary depending on the time since transplant and institutional protocols, commonly targeting 8-12 ng/mL early post-transplant and 5-8 ng/mL long-term. Steroid-free protocols are increasingly adopted to minimize metabolic side effects.
Surveillance
Serum creatinine remains the primary marker of graft function, with rising levels prompting evaluation for rejection, obstruction, or vascular complications. Some centers perform protocol biopsies at 3 to 6 months post-transplant to detect subclinical rejection. When acute dysfunction occurs, allograft biopsy is the gold standard for diagnosis, classified according to the Banff criteria.
<image>Completed renal transplant operative photograph or illustration showing the transplant kidney in the right iliac fossa with perfused, pink parenchyma, labeled vascular anastomoses to the external iliac artery and vein, the ureter coursing to the bladder with a visible Lich-Gregoir anastomosis, Jackson-Pratt drain positioned near the allograft, and Foley catheter in the bladder</image>
Key Clinical Pearls
The left kidney is preferred for living donor nephrectomy because its longer renal vein facilitates venous anastomosis. The right iliac fossa is the favored recipient site for the first transplant due to the more superficial and accessible external iliac vein. Venous anastomosis is performed before arterial anastomosis to establish outflow and minimize warm ischemia-reperfusion injury. The Lich-Gregoir extravesical ureteroneocystostomy is the most widely used technique, and placement of a double-J stent significantly reduces urine leak rates. Cold ischemia time is a modifiable factor; prolonged CIT beyond 24 hours markedly increases the risk of delayed graft function and reduces long-term graft survival. Finally, ligation of lymphatics overlying the iliac vessels during dissection is critical, as failure to do so is the primary cause of postoperative lymphocele.
References
- Danovitch GM. Handbook of Kidney Transplantation. 6th ed. Philadelphia: Lippincott Williams & Wilkins; 2017.
- Nicol DL, Mendelssohn DC, eds. Surgical Techniques in Kidney Transplantation. In: Campbell-Walsh-Wein Urology. 12th ed. Philadelphia: Elsevier; 2021.
- Slagt IK, Ijzermans JN, Visser LJ, et al. Comparing techniques for ureteral implantation in renal transplantation: a systematic review and meta-analysis. Kidney Int Rep. 2022;7(5):981-993.
- Irish WD, Ilsley JN, Schnitzler MA, et al. A risk prediction model for delayed graft function in the current era of deceased donor renal transplantation. Am J Transplant. 2010;10(10):2279-2286.
