Renal Allotransplantation

Transplantation of a kidney allograft and subsequent immunosuppression in patients with renal failure demand surgical precision and zero tolerance for errors of judgment or technique. The devastating consequences of vascular, urologic, and infectious wound complications in renal transplantation, with their associated morbidity, mortality, and graft loss, are well documented. Fortunately, strict adherence to techniques and principles outlined in this chapter can reduce the incidence of these problems to very low levels.

INDICATIONS FOR SURGERY

Indications for surgery include patients with chronic renal failure. Contraindications to renal allograft transplantation include a history of cancer (especially hematopoietic, renal cell carcinoma, or melanoma), active infections, and patients who are a poor operative risk. Relative contraindications include oxalosis and other metabolic disorders, psychological instability, and focal glomerulosclerosis.

ALTERNATIVE THERAPY

The alternative to renal allotransplantation is chronic dialysis.

SURGICAL TECHNIQUE

Preparation of the Patient

The prospective transplantation recipient should be in metabolic, fluid, and electrolyte balance to avoid perioperative hyperkalemia, unstable blood pressure, pulmonary edema, dehydration, or difficult operative hemostasis associated with inadequate dialysis. When dialysis can be scheduled in advance, as with living related donor transplantation, it should be performed on the day before surgery. The patient’s cardiopulmonary status needs to be well documented, and central venous pressure monitoring is routine. Swan–Ganz monitoring is often useful.

The entire abdomen is shaved and prepped after the induction of anesthesia and insertion of an indwelling 16 or 18 Fr Foley catheter. Any urine present in the bladder is submitted for culture. Then the bladder is distended with 150 ml or more of a saline solution containing Neosporin GU Irrigant. This greatly facilitates the anterior cystotomy later in the procedure and, in addition, protects against possible wound contamination when the bladder is opened. After instillation of the antibiotic solution, the catheter is clamped. The clamp is removed only after cystotomy closure is completed.

Incision and Iliac Fossa Dissection

A lower quadrant curvilinear incision is extended from the symphysis pubis passing 2 cm medial to the anterior superior iliac spine and up to about 4 to 5 cm below the lower costal margin. The upper half of the incision is extended through the external oblique, internal oblique, and transversus abdominis muscles; in the lower half of the incision, the anterior rectus fascia is incised. The rectus muscle can then be dissected inferiorly to its tendinous insertion on the symphysis pubis and retracted medially. In thin patients we prefer to keep the cephalad portion of the incision also within the lateral border of the rectus muscle, thereby obviating any transection of muscle and simplifying the closure. The inferior epigastric vessels are identified as they pass across the incision and are preserved for possible use later. Next, an anterolateral retroperitoneal fascial plane is developed, permitting extraperitoneal entry into the iliac fossa.

With medial retraction of the peritoneum, the spermatic cord in the male patient or round ligament in the female patient is easily identified. In men, some of the connective tissue around the cord is freed to permit easier retraction. Usually, cord ligation should be avoided to prevent hydrocele formation, testicular atrophy, or infertility. In women, the round ligament is divided and ligated. Further development of the extraperitoneal space in the iliac fossa is accomplished with exposure of the distal common and external iliac artery. The insertion of a self-retaining retractor at this point assures adequate exposure for the subsequent iliac vessel dissection and vascular anastomoses.

The dissection and skeletonization of the iliac vessels must be performed in a manner that allows secure ligation of the divided lymphatics passing along and across these vessels. Usually, this process is best approached on the medial aspect of the external iliac vein, working cephalad with a right-angle clamp toward the internal iliac artery, which crosses the vein. In some cases, especially when the donor kidney is large or has a short vein, the internal iliac artery must be sacrificed in order to achieve sufficient mobilization of the underlying vein. The iliac vein can be skeletonized as far cephalad as the vena cava if necessary. Posterior venous tributaries must be divided to permit maximum anterior mobility of the iliac vein. It is best to ligate all tributaries doubly with 2-0 or 3-0 silk in continuity before division because a double-clamping maneuver may sometimes result in injury or avulsion of a poorly accessible stump during ligation. Hemostasis then can be achieved only with difficulty and with risk of obturator nerve injury. Unless the internal iliac artery already has been selected for an end-to-end allograft anastomosis, right-angle clamp dissection is used to partially skeletonize the common and external iliac arteries. The tissue overlying the arteries and containing the lymphatics is sequentially separated, doubly ligated with 3-0 silk, and divided, a strategy that greatly reduces the incidence of lymphocele. Again, this tissue should be doubly ligated before it is incised, in contrast with double clamping and division of the tissue. Just as with the vein, the anterior separation of tissue over the iliac artery is more easily performed in a cephalad direction.

At this point, palpation of the common iliac bifurcation and internal iliac artery determines the suitability of the internal iliac artery for an end-to-end anastomosis with the renal artery and the need for endarterectomy. If there is moderate or severe atherosclerosis extending into the bifurcation, or great size disparity, the internal iliac artery is usually not used. If an endarterectomy can be performed safely, or if there is little evidence of atheroma in the internal iliac vessel, skeletonization of this vessel prepares it for end-to-end anastomosis. Before skeletonization is begun, the lymphatics on the medial aspect of the iliac bifurcation should be doubly ligated and divided. If the internal iliac artery is to be used, it may be clamped proximally with a Fogarty clamp and divided distal to its bifurcation with appropriate ligation of the distal stumps deep in the pelvis. The mobilized internal iliac artery is irrigated with heparinized saline solution.

Allograft Positioning and Vascular Anastomoses

Before recipient vessel anastomotic sites are selected, visualization of the ultimate resting place for the allograft lateral or anterior to the iliac vessels should be considered, with all anatomic factors taken into account. The iliac vein is prepared for the end-to-side renal vein anastomosis by placement of clamps proximal and distal to the proposed venotomy. Fogarty clamps usually serve this purpose well. Excision of a thin ellipse of vein produces an ideal venotomy. The isolated segment of the iliac vein is irrigated with heparinized saline. After this, four 6-0 cardiovascular sutures are placed at the superior and inferior apices and at the midpoints of the medial and lateral margins of the venotomy. These sutures later are passed through corresponding points on the donor renal vein or vena cava patch for a four-quadrant end-to-side anastomosis.

If a cadaveric kidney is used, the allograft is removed from cold storage or perfusion preservation at this point. With living related transplantation, the flushed and cooled graft is obtained from the live donor in an adjacent operating room.

The kidney is secured in a sling or a 3-inch stockinette4 containing ice slush and held in position for the vascular anastomosis by the assistant. A clamp is used to secure the sling to relieve the assistant from holding the kidney in position with the hands, which might accelerate warming of the kidney during the performance of the vascular anastomoses.

The previously placed four sutures through the iliac vein are passed through the corresponding points of the donor renal vein, Carrel patch, or vena cava conduit and secured, bringing the renal vein into juxtaposition with the iliac vein. The medial and lateral sutures are retracted to separate the venotomy opening and facilitate rapid anastomosis without inadvertent suturing of the back wall. With the table rotated laterally, the superior suture is used as a running suture down the medial side of the renal vein to meet the inferior suture running up. The lateral suture line is then run in similar fashion after the table has been rotated medially. The clamps on the iliac vein may be left in place until completion of the arterial anastomosis, but application of a finger Fogarty or a bulldog clamp across the renal vein at this time allows for removal of the iliac vein clamps and earlier restoration of venous return from the lower extremity.

If the internal iliac artery is to be used for the arterial anastomosis, an end-to-end anastomosis is then performed with the renal artery. The two vessels are positioned to allow a gentle upward curve from the iliac bifurcation to the kidney by fixating the superior and inferior arterial apices with interrupted 6-0 cardiovascular suture. The anastomosis is completed with continuous or interrupted sutures. With the kidney resting in the iliac fossa or suspended in a sling, the initial interrupted suture may be placed midway between the apical sutures on the anterior vessel walls facing the operator, thus allowing better approximation of the opposing arterial margins, particularly when a discrepancy exists in the size of the vessels. Subsequently, the remaining sutures are placed to approximate each anterior quadrant. Next, the previously placed apical sutures are used to rotate the arteries so that the posterior vessel walls are now in the anterior position for subsequent interrupted or running suture placement. Just as before, a suture placed midway between the apical sutures again divides the rotated posterior vessel walls into quadrants for subsequent suture placement. A preference for interrupted sutures instead of a running suture in this end-to-end anastomosis prevails when one needs to avoid absolutely any pursestring effect that might occur from a running suture or to achieve optimal accommodation of the two vessels to each other when a size or thickness discrepancy exists.

In most cases, the internal iliac artery is left intact to preserve potency in men as well as gluteal and pelvic blood supply in the elderly. Therefore, end-to-side anastomosis of the renal artery to the external or common iliac artery is chosen more commonly than the end-to-end procedure just described. This anastomosis usually is placed cephalad to the level of the venous anastomosis. The location of clamp placement must be carefully selected so as not to disrupt existing arteriosclerotic plaques and precipitate embolization or thrombosis. A longitudinal incision is made on the anterior or anterolateral portion of the iliac artery segment with a #11 blade knife, and a 4.8- or 5.6-mm aortic punch is used to prepare an ideal oval arteriotomy. After the incision is made, regional heparinization of the lower extremity may be accomplished by instilling about 80 to 100 ml of heparinized saline (1,000 units/100 ml) into the distal iliac limb. Systemic heparinization is usually not necessary. This anastomosis is also performed with 6-0 cardiovascular continuous or interrupted sutures after initial fixation of the end of the renal artery to an apex of the arteriotomy with suture cinched down by parachute technique.

The previously placed sling around the kidney is removed. It is desirable to have obtained preoperative assessment of the recipient for existing cold agglutinins, because moderate to high titers of these agglutinins require warming of the kidney before the circulation is reestablished. The vascular clamps are released after IV infusion of mannitol and methylprednisolone, venous clamps before arterial. At this point, the patient should be judiciously overhydrated with saline and albumin, and a dopamine drip should be ready to optimize renal blood flow if needed.

Multiple Renal Vessels

Although the Carrel patch may frequently be used with single arteries and veins, a cadaveric kidney with multiple renal arteries perfused through the aorta is especially well suited to an end-to-side anastomosis of a Carrel patch encompassing the multiple arteries. If the vessels are close to each other, a single Carrel patch is sufficient. If the vessels are more than 2 cm apart, we prefer two Carrel patches. The Carrel patch of donor aorta is fashioned to accommodate the multiple vessels, and its anastomosis to the common or external iliac artery is performed with continuous 5-0 or 6-0 cardiovascular sutures after an arteriotomy that accommodates the width and length of the Carrel patch. This anastomosis is best performed by fixating the patch at the superior and inferior apices of the arteriotomy or by parachute technique. Each suture limb runs away from the apex.

The presence of multiple arteries in related donor transplantation is known in advance because all living related donors have preoperative arteriograms. Most donors have at least one kidney with a single artery, but, at times, a donor kidney with double arteries or triple arteries must be used. These arteries cannot be taken with a Carrel patch because of the risk to the donor. In these instances, several strategies for arterial anastomoses are possible: double end-to-side renal arteries to iliac artery, end-to-end superior renal artery to internal iliac artery with end-to-side inferior renal artery to external iliac artery, and implantation of an accessory artery end-to-side into the larger main renal artery, with the larger renal artery anastomosed to the internal, external, or common iliac artery. If two renal arteries are of similar diameter, the spatulation edges of the renal arteries can be joined with a running 6-0 or 7-0 cardiovascular suture to create a single bifurcating artery. An accessory artery to main renal artery anastomosis should be performed with ex vivo bench technique in cold ice slush before the renal vein anastomosis is done. Finally, some recipients have a deep inferior epigastric artery that is suitable for end-to-end 7-0 suture interrupted anastomosis of a small lower-pole artery, which may be essential for ureteral viability.8 Our experience in more than 30 cases with this technique has been excellent; no ureteral ischemia or necrosis has occurred.

Ureteroneocystostomy

Some patients are prepared for kidney transplantation by creation of an ileal loop or isolated ileal stoma to divert urine from a dysfunctional or absent bladder. These techniques are beyond the scope of this discussion. In addition, when the donor ureter is absent or damaged, the recipient ureter may be used for ureteroureterostomy or ureteropyelostomy to the allograft.

Various modifications of the Politano-Leadbetter, Paquin, and Lich techniques are used for allograft ureteral implantation into the bladder. In our experience, when the bladder is very small or the donor ureter is very short, an extravesical technique is best.6 Otherwise, we prefer the ease and reliability of a transvesical approach without a formal submucosal tunnel.7 In either case, previous filling of the bladder facilitates a longitudinal anterior cystotomy with minimal trauma to the bladder wall. In the transvesical approach, the bladder dome is packed and retracted cephalad, exposing the bas fond. An oblique tunnel is created in the bladder floor using a tonsil clamp directed toward the trigone from outside the bladder. This maneuver prevents subsequent angulation of the ureter when the bladder is distended. An 8 Fr Robinson catheter or heavy silk is passed through the tunnel in retrograde fashion and secured to the donor ureter.

The ureter is pulled down and brought into position in the bladder by gentle traction. This maneuver avoids any handling of the ureter, which is important because the ureter of the transplanted kidney receives its blood supply exclusively from the renal vessel branches that course in its adventitia. In male patients, it is important to pass the ureter beneath the spermatic cord. Intravesically, the ureter is hemitransected about 4 cm from its entrance site into the bladder and spatulated about 1 cm.

Four sutures of 4-0 chromic catgut are usually sufficient for an anastomosis incorporating bladder mucosa and muscularis as the ureteral transection is completed. When the apical stitch also catches ureteral adventitia 1 to 2 cm above the apex, a nice everted ureteral nipple may be produced. This eversion is especially desirable with patulous ureters. The ureter is not stented routinely. A no-touch technique is essential to avoid producing vascular insufficiency, ureteral necrosis, and urinary extravasation from injury to the adventitial vascular network of the ureter.

The oblique bladder tunnel and muscle hiatus must accommodate the ureter comfortably to avoid postoperative obstruction from edema, and a gentle oblique course of the ureter must be ensured so that no kinks, twists, or obstructions occur. This attention is important because the ureter of a transplanted kidney crosses the iliac vessels in a much more caudal position than the native ureter. A little redundancy of the ureter is established outside the bladder to ensure that the ureteroneocystostomy is done without tension and that postoperative allograft swelling will not unduly stretch or angulate the ureter. Patency of the ureteroneocystostomy is confirmed by gently passing a 5 Fr feeding tube or an 8 Fr or smaller soft Robinson catheter toward the renal pelvis.

Kidneys with a double ureter can also be transplanted successfully. These ureters should be dissected en bloc within their common adventitial sheath and periureteral fat so that the ureteral blood supply is protected. The technique of ureteroneocystostomy is essentially the same as with a single ureter, except that the ureters are brought through together side by side in a nonconstricting tunnel. The distal end of each ureter is spatulated, and the adjacent margins are approximated with 5-0 chromic catgut.

To ensure a watertight closure, the cystotomy incision is closed in three layers. The first 3-0 chromic running suture secures the full thickness of the bladder near the bladder neck and closes the mucosal layer. The second 2-0 chromic running suture is an inverting layer of muscularis. The third 2-0 chromic layer inverts the adventitia. Each layer should overlap the immediately underlying layer about 0.5 cm at each end of the cystotomy closure to avoid urinary extravasation at these two points.

Pediatric Kidneys

Although en bloc transplantation of kidneys from very young children is often desirable,5 it is not necessary to transplant both kidneys from young children en bloc each kidney can be used for a different recipient, as is the case with adult cadaveric donors, using Carrel patches of donor aorta and vena cava. A Carrel patch is mandatory in these cases because direct implantation of a small vessel into a much larger or diseased vessel may result in thrombosis or produce functional stenosis as the kidney grows. When the en bloc technique is used, the two ureters are implanted separately and stented. Pediatric kidneys have proven to be excellent donor grafts for carefully selected adults and children. Avoidance of older recipients or diabetics with advanced arteriosclerosis will minimize the potential for thrombosis. Rapid growth and hypertrophy occur in the immediate posttransplantation period. If early rejection can be avoided, these allografts achieve adult size and function in adult recipients within several weeks.

Pediatric Transplantation

In small children, the iliac fossa is not large enough to accommodate a kidney from an adult donor, and the pelvic vessels in a small child are so small that the disparity between the donor renal vessels and the recipient vessels precludes the technique described for adults. In these small children, graft implantation must use the recipient aorta and vena cava, which is best accomplished through a right-sided retroperitoneal or transperitoneal midline abdominal incision that provides ready access to the great vessels as well as the urinary bladder. After the right colon is reflected medially, the right kidney is usually removed to make room for the allograft. The vena cava is then freed from the level of the right renal vein inferiorly to its bifurcation or beyond. Posterior lumbar veins are doubly ligated with 5-0 silk and divided. Mobilization of the vena cava is important to facilitate the end-to-side anastomosis of the renal vein, which is performed with running 6-0 ardiovascular sutures, as described for the adult . Performing the venous anastomosis superiorly allows room for an end-to-side anastomosis of the renal artery to the inferior abdominal aorta. Aortic mobilization should be limited to its distal portion, from the level of the inferior mesenteric artery, and including both common iliac arteries. The segment of the aorta to be used for the end-to-side renal artery anastomosis can be isolated by a superior pediatric vascular clamp and by two inferior clamps or silastic loops on the common iliac arteries. The end-to-side anastomosis is performed with interrupted 6-0 cardiovascular sutures.

Important to the revascularization of an adult kidney in small children is the need to anticipate the impending consumption of several hundred milliliters of effective blood volume by the renal allograft. Initiation of blood transfusion before beginning the vascular anastomoses will avoid hypotension after release of the vascular clamps. When the vascular anastomoses are completed, the superior aortic clamp must be kept loosely in place until it is clear that hypotension is not a problem. Immediately after establishing circulation in the graft, the anesthesiologist must obtain blood pressures at 30-second or 1-minute intervals until stabilization is assured. The ureteral implantation is carried out as described except that the ureter must be passed retroperitoneally behind the bladder near the midline.

Wound Closure

Except in unusual cases, the allograft ureter is not stented, and the space of Retzius and iliac fossa are not drained. Jackson–Pratt suction may be employed, but Penrose drains are never used. If good hemostasis has been obtained, and if the principles of implantation as outlined in this chapter have been followed, there is no need for postoperative drainage other than a urethral catheter. The optimal period of Foley catheter drainage is debatable. We prefer to remove the catheter within 48 hours unless the patient has worrisome hematuria, large diuresis, or poor bladder function.

Before wound closure, the wound is thoroughly irrigated with saline. The wound is then closed using a 1 Maxon running suture to approximate transversus abdominis and internal oblique muscles in a single-layer closure; the adjacent fascia is included inferiorly at the tendinous insertion of the rectus muscle. Next, the rectus fascia anteriorly and the fascia of the external oblique are approximated with 1 Prolene running suture.

The subcutaneous tissue is thoroughly irrigated with saline and then may be approximated with interrupted 2-0 or 3-0 sutures. These sutures are placed about 2 to 3 cm apart and include both Scarpa’s fascia and the underlying fascia superficially. In this manner, one can obliterate dead space in the subcutaneous area in which a seroma in an immunosuppressed patient might become secondarily infected. The skin is approximated with interrupted fine nylon sutures or staples.