Renal Autotransplantation

Renal autotransplantation is a safe and effective procedure to reconstruct the urinary tract. The first successful surgery was performed by Hardy in 1963 in a patient with severe ureteral injury following aortic surgery. The advent of microvascular techniques and renal preservation extends the scope of the procedure, allowing for successful extracorporeal (bench) surgery and subsequent autotransplantation. Current indications of autotransplantation include renal-vascular disease, severe ureteral damage, tumors of the kidney and ureter, complex nephrolithiasis, and retroperitoneal fibrosis. The procedure is technically demanding and is contraindicated in the setting of severe occlusive atherosclerosis of the iliac arteries. The advantages of autotransplantation include optimal surgical exposure, bloodless surgical field, and hypothermic protection of the kidney from ischemia. In cases of malignancy, there is less risk of tumor spillage and better assessment of tumor margins than by in vivo renal reconstruction. It is possible that this procedure may be underutilized because a good proportion of urologists are unfamiliar with the principles of renal homotransplantation.

DIAGNOSIS

Preoperative renal and pelvic arteriography should be performed to define the renal artery anatomy and ensure disease-free iliac vessels. In cases where autotransplantation is performed for the management of ureteral disease, ureteral involvement can be assessed by intravenous or retrograde pyelography. A CT scan of the pelvis may be beneficial in cases of retroperitoneal fibrosis to assess pelvic extension of disease.

INDICATIONS FOR SURGERY

Renal autotransplantation is particularly attractive for a variety of vascular lesions affecting the aorta and renal artery. These include traumatic arterial injuries, renal artery stenosis with extension into the segmental branches (fibromuscular disease), large aneurysms, or arteriovenous fistulas. Other vascular indications include aortic aneurysms involving the renal arteries (Marfan’s syndrome) and occlusive aortic disease.

In patients with central, intrarenal tumors or multiple tumors in a solitary kidney, renal autotransplantation with extracorporeal surgery is a useful technique. Following radical nephrectomy and exterior hypothermic renal perfusion, the kidney is dissected beginning in the hilum. The vasculature to the tumor is ligated. After tumor-free margins are achieved, autotransplantation is carried out.

Renal autotransplantation allows for a direct anastomosis of the renal pelvis to the bladder. Therefore, it can be used in cases of ureteral damage or long ureteral lesions such as iatrogenic ureteral injuries, ureteral strictures, ureteral tumors, ureteral tuberculosis, failed urinary diversions, and retroperitoneal fibrosis. The procedure can also be used to facilitate stone passage in patients with complex nephrolithiasis. Renal autotransplantation has been effective in controlling the symptoms related to loin-pain hematuria syndrome.

ALTERNATIVE THERAPY

Replacement of the ureter for reconstruction of the urinary tract may be performed with a segment of ileum. The advantages of an ileal ureter over autotransplantation are threefold: (a) the procedure is technically less demanding; (b) vascular anastomosis is not necessary; and (c) bladder argumentation with bowel can be done simultaneously. Disadvantages include mucus production, metabolic and electrolyte imbalance, propensity for bacteriuria, and the need for indefinite radiologic surveillance of the ileal segment. Contraindications include intestinal diseases, hepatic dysfunction, and renal insufficiency (serum creatinine greater than 2.0 mg/dl).

For severe renovascular disease, the first surgical options typically include in situ reconstruction. This may involve endarterectomy or aortic–renal or splenorenal bypass grafting. When these techniques are not possible and microvascular reconstruction is required, autotransplantation becomes the procedure of choice.

SURGICAL TECHNIQUE

Perioperatively, a brisk diuresis should be induced by IV hydration and 12.5 g mannitol given 1 hour before surgery. This will minimize ischemic injury to the kidney and hasten restoration of renal function. A broad-spectrum antibiotic is also administered 1 hour before surgery. During the operation, an adequate central venous pressure should be maintained with fluid boluses as needed. Renal autotransplantation is a two-step procedure: first, the kidney is removed; then, it is transplanted. The surgical approach to removing the kidney is similar to that of living-donor nephrectomy. However, the operation may be complicated by the particular disease process necessitating the surgery. Typically, two incisions are needed: the first, either a subcostal transperitoneal or extrapleural–extraperitoneal flank to remove the kidney; and the second, a lower-quadrant curvilinear or midline incision to access the iliac fossa. In thin patients, an alternative approach is a single midline incision from the xiphoid to the symphysis pubis, although the exposure to the kidney is not optimal.

Nephrectomy

After the peritoneum and colon are reflected medially, Gerota’s facia is incised. The perinephric fat is sharply dissected off the renal capsule with minimal spreading using Metzenbaum scissors. Excessive retraction of the kidney should be avoided because that may result in subcapsular hematomas or capsular tears. The adrenal gland should be carefully separated from the upper pole of the kidney. In cases where ureteral continuity is not preserved, the distal ureter is isolated and transected before the dissection of the renal hilum. The ureteral stump can be tied with #0 chromic catgut suture. The ureter should be maintained with its vascularity and the gonadal vein. To maximize ureteral viability, the tissue between the lower pole of the kidney and the ureter should be kept intact. Urinary output can then be assessed before the renal pedicle is approached.

On the right side, the vena cava is carefully isolated from the surrounding tissue. The gonadal vein can be ligated at its insertion on the vena cava. The renal vein should be identified anterior to the renal artery. Accessory renal veins can be ligated, but accessory renal arteries must be maintained. Careful dissection of the renal artery is performed toward the aorta by slightly retracting the vena cava with a closed forceps or vein retractor. After a further 12.5 g of mannitol has been given, a right-angle clamp is placed on the renal artery, and it is transected. A Satinski vascular clamp is then placed proximal to the renal vein ostium, and the renal vein is transected. The renal artery can be tied with #0 silk ties or, alternatively, one #0 silk tie and a #0 silk ligature. We have found that the renal vein retracts after transection and that placement of a second larger Satinski clamp behind the first allows for a less stressful closure of the renal ostium. A 5-0 Proline suture is tied at one end, run down to the other end, back to the first, and retied. On the left side, the artery is divided at the aorta; the vein is divided anterior to the aorta and tied with two #0 silk sutures.

Renal Preservation

Once the kidney is removed, it is immersed in ice-cold slush at 4°C. The renal artery is flushed with either a Collins intracellular electrolyte solution or a lactated renal solution with 10,000 units/liter of heparin and 50 mEq/liter of sodium bicarbonate. Flushing is continued until the effluent from the renal vein is clear. An adaptor is used to hold a good seal during flushing. Adequate flushing allows about 4 to 6 hours of renal preservation. If extracorporeal renal surgery is required, a second team can close the flank incision. In closure of the flank, a strong monofilament absorbable suture such #1 PDS or Maxon is used. Anteriorly, the transversus abdominis, internal oblique, and external oblique muscles are closed separately. Often the transversus and internal oblique are closed together. Closure should begin after flexion is removed from the operating room table. Posteriorly, the intercostal muscles and latissimus dorsi are closed as separate layers.

Autotransplantation

The patient is placed in the supine position and draped. A Foley catheter carries 150 cc of 1% neomycin sulfate solution into the bladder, and the catheter is clamped. A curvilinear incision is made, extending from one fingerbreadth above the pubis to two fingerbreadths above the anterior superior iliac spine. The incision is carried down to the rectus facia. The rectus facia, the external oblique, internal oblique, and transversus abdominis muscles are opened along the line of the incision. The lateral edge of the rectus muscle is transected off the pubis to get better exposure to the pelvis. The epigastric vessels are transected beneath the transversus abdominis muscle and tied with two 2-0 silk ties. The round ligament or the spermatic cord is doubly ligated. In young men, the spermatic cord is preserved and displaced inferomedially. The peritoneum is reflected medially to expose the iliac vessels and bladder. A Buckwalter retractor is placed into the wound to provide optimal exposure.

The next part of the procedure is similar to that used for renal homotransplantation. The iliac vessels are evaluated for potential size for anastomosis with the renal artery. If the caliber of the internal iliac artery is sufficient, and there is not significant plaque formation, then this vessel is selected. It is mobilized from the common iliac to the first branch, the superior gluteal artery. A bulldog vascular clamp is placed just beyond the origin of the internal iliac artery, and a right-angle clamp is placed distally (Fig. 16-2). After transection of the vessel, the distal portion is tied with #0 silk tie. The bulldog vascular clamp is opened to test for flow. The proximal portion of the vessel is flushed with 2,000 units of heparin mixed as follows: 10,000 units per 100 cc normal saline. If a plaque is discovered, it can be trimmed back, an endarterectomy can be performed, or it can be tacked down with 6-0 silk. Further dissection of the common iliac and external iliac artery is not required. The external iliac vein is mobilized for 5 to 7 cm with special care to ligate any lymphatic vessels with 4-0 silk to prevent lymphocele formation.

When the internal iliac artery is unavailable, the external iliac artery is selected. After the external iliac artery is mobilized for 4 to 5 cm, an end-to-side anastomosis is performed between it and the renal artery. Wide mobilization of the external iliac artery may result in kinking of the vessel. Vascular clamps are placed proximally and distally, and an arteriotomy is performed. Typically only a slit is needed, and an ellipse of the anterior wall need not be removed. The distal artery is flushed with 2,000 units of dilute heparin with a red rubber catheter. A Satinski vascular clamp is placed distally on the external iliac vein, and a bulldog is placed proximal to the venotomy. The iliac vein is then carefully incised with a #11 blade scalpel to accommodate the renal vein. Four 5-0 Proline sutures are placed on the external iliac vein in an outside-to-in fashion, one at each apex and one at the midpoint on each side of the venotomy.

The kidney is placed in the operative field. An assistant holds the kidney with a surgical sponge in an anatomic position with the ureter inferiorly. To minimize warm ischemia while the anastomosis is accomplished, the kidney is irrigated with cold saline. The four Proline sutures in the external iliac vein are then brought through the renal vein in an inside-to-out fashion. The kidney is lowered into the wound, and each suture is tied with the knots on the outside. The two apex sutures are used to close the venotomy. The midpoint sutures are placed with mild traction to keep the back wall from being incorporated in the running suture. The internal iliac artery is then anastomosed to the renal artery end to end with 6-0 siliconized silk suture. The artery should be placed posterior to the renal vein to preserve anatomic relationships. The first two sutures of the arterial anastomosis are placed at either apex with double-armed needles such that the knots are on the outside. The remainder are placed with single-armed needles. We prefer an anastomosis with interrupted sutures when the internal iliac artery is used. Sutures should be placed close enough to avoid any gaps, especially at the apex. After one side is complete, the apical sutures are rotated to give exposure to the back wall. If the external iliac artery is used, the arteriotomy should be staggered with the venotomy to avoid kinking of the vessels. The anastomosis is performed with two to four continuous 6-0 Proline sutures. After completion of the anastomosis, oxidized cellulose is wrapped in small pieces around the arteriotomy and venotomy. The venous clamps are then removed, followed by the arterial clamps. It is important to maintain adequate intravascular volume with colloid or blood, especially when the clamps are removed, so that the kidney is well perfused. If this produces an excessively elevated central venous pressure, intravenous furosemide (Lasix) should be administered.

Occasionally, renal autotransplantation can be performed with the ureter left intact. Although it will follow a redundant course to the bladder, normal peristalsis will provide effective drainage from the kidney. Care must be taken to avoid positioning the kidney so as to produce an obstruction of the ureter.

If the ureter is transected, the urinary system can be reconstructed by a ureteroneocystostomy, ureteroureterostomy, pyeloureterostomy, or a pyelovesicostomy. We prefer an extravesical ureteroneocystostomy when there is adequate length of nondiseased ureter for a tension-free anastomosis. The Buckwalter retractor is repositioned to provide better exposure to the lateral wall of the bladder. A 2- to 3-cm tunnel is made in the bladder wall by incising the posterior lateral serosa and detrusor muscle. After the margins of the detrusor are retracted with 3-0 chromic stay sutures, the mucosa is mobilized and allowed to bulge. An ellipse of the mucosa is removed from the apex of the tunnel, and the spatulated ureter is anastomosed with the bladder mucosa using a continuous 50 chromic catgut suture. Two sutures are used, each of which incorporates 180 degrees of the anastomosis, and are tied without tension. The anastomosis is performed over a 4.8 Fr double-J ureteric stent, which is positioned into the bladder after the bladder mucosa has been opened. The stent will be removed in the postoperative period.

The detrusor is closed over the ureter with interrupted 3-0 chromic catgut suture. The tunnel should allow passage of a right-angle clamp between the ureter and overlying muscle. The wound is irrigated with a 1% neomycin solution. No external drains are required if the ureteral reimplantation is watertight.

In cases where the upper ureter is diseased, the area is removed, and the proximal ureter or renal pelvis is anastomosed to the normal lower ureter. The ureteroureterostomy or pyeloureterostomy is performed over a ureteric double-J stent by end-to-end anastomosis of the spatulated lower ureter to either the spatulated upper ureter or the renal pelvis. If the entire ureter is not viable, or for recurrent stone disease, a pyelovesicostomy is performed. This technique can be performed with a Boari flap and end-to-end anastomosis of the renal pelvis to tubularized bladder. The Boari flap should be secured to the psoas muscle to avoid tension on the anastomosis.

The wound is then closed in layers. The rectus muscle is approximated back to the tendinous insertion at the pubic bone with a #0 Proline suture. The internal oblique and transversus abdominis are closed with a #0 Proline suture. The external oblique is closed with continuous #0 Proline. The subcutaneous layer is closed with 3-0 Dexon and the skin is closed with 3-0 nonabsorbable suture or clips.

For optimal renal perfusion during the immediate postoperative period, the central venous pressure should be maintained adequately, and the diastolic blood pressure kept at 85 mm Hg or higher. Mild hypertension is preferred over normotension or mild hypotension. Aspirin can be started postoperatively to reduce the risks of graft thrombosis. A renal scan is obtained on the first postoperative day to document renal perfusion and again about postoperative day 7. Broad-spectrum antibiotics are administered during the immediate postoperative period to maintain sterile urine and help prevent infection of the vascular grafts. The ureteral stent is left in place for 2 to 3 weeks and is removed during outpatient cystoscopy. The Foley catheter is removed on postoperative day 5. It may be removed sooner if a ureteroureterostomy or pyeloureterostomy is performed, but it should be kept in place for 5 days following a pyelovesicostomy or ureteroneocystostomy. An intravenous pyelogram or a cystogram is obtained 1 to 2 weeks after surgery to evaluate ureteral integrity.

OUTCOMES

Complications

Early postoperative complications include bleeding from the vascular anastomosis, renal artery or vein thrombosis, distal extremity embolization, or urinary extravasation. Bleeding from a disrupted anastomosis is a rare event but requires immediate exploration. It is usually associated with anastomosis to diseased vessels or errors in surgical technique. Peripheral collateral vessels from the renal hilum can attain significant size if there is stenosis of the renal artery or vein and can be a source of postoperative bleeding. Renal artery or vein thrombosis occurs in fewer than 2% of cases and should be ruled out in cases of oliguria following autotransplant of a solitary kidney. The diagnosis is made by renal scan; if it is made without delay, salvage of the autotransplant should be attempted. Any significant hypotension or hypovolemic event in the postoperative period or error in surgical technique can predispose to this threat.

Distal extremity embolization as a result of dislodging of plaque during aortic clamping or unclamping can occur, especially with diseased blood vessels. Heparinization at the time the vessels are prepared aids in preventing this problem, but the distal pulses and color of the legs should be assessed after arterial clamps are opened. Deep venous thrombosis can result in propagation of clot from the renal vein. Intimal injury, low-flow states, and venous obstruction can predispose to this condition.

Urinary extravasation is the most common complication from autotransplantation. Placement of a ureteric double-J stent diminishes this risk. If a leak occurs, it should be treated by a percutaneous nephrostomy. In circumstances when these conservative measures fail, such as when the distal ureter is ischemic, operative repair is required.

The most common late complications include renal artery stenosis, ureteral stricture, and ureterovesical reflux. Renal artery stenosis may be manifested by hypertension or impaired renal function. Diagnosis is made by renal scan and digital subtraction angiography. Initial management should be percutaneous angioplasty. Obstruction of the urinary system demonstrated by pain or impaired renal function can be managed by dilation and stenting.

Results

Bodie et al. reported on 24 autotransplanted kidneys in 23 patients in whom the primary indication was to replace all or a major portion of the ureter. There were no operative deaths reported. Of the 24 autografts, three were ultimately lost (12%). The function of the remaining grafts was stable or improved postoperatively.1 Novick reported successful outcomes in 29 of 30 patients who underwent autotransplantation for the management of intrarenal branch arterial lesions.

Van der Valden reported on six cases of renal carcinoma treated by extracorporeal surgery and autotransplantation. Dialysis was not required, and the patients’ blood pressure improved or remained within normal limits. Mean follow-up time was 54 months, with three patients dying during this period. Zincke and Sen performed extracorporeal surgery and autotransplantation in 15 kidneys. Of these, 11 had renal cell carcinoma, and four had transitional cell carcinoma. Three autografts were lost because of venous and arterial thrombosis in two and necrosis of the renal pelvis and ureter in one. The remaining patients were dialysis-free with stable creatinine values. Other complications cited included a caliceal fistula requiring closure in one patient and an intimal injury requiring partial replacement of the external iliac artery with a Gore-Tex graft.10 Novick et al. observed an increased incidence of temporary and permanent renal failure for extracorporeal compared to in situ partial nephrectomy for renal cell carcinoma.8 Postoperative initial nonfunction occurred in five of 14 patients (36%) undergoing autotransplantation but in only two of 86 patients (2.3%) who underwent an in situ procedure. Permanent renal failure occurred in two of 14 (14.3%) autotransplanted patients and in one of 86 managed in situ(1.2%).

Renal autotransplantation is a rare procedure that is technically demanding with several potentially serious complications. However, in a variety of instances, it may be of great utility for organ salvage and should be included in the armamentarium of the urologist.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: