Living donor: nephrectomy and back-table surgery

1. A different kind of nephrectomy

Living donor nephrectomy involves two patients: the donor, who must go through the surgery with the lowest possible risk, and the recipient, who needs to receive an organ in the best possible condition.

This creates a particular situation: we must never technically improve the graft at the cost of unjustifiably increasing the donor's risk. The priority remains the safety of the healthy person who is donating.

But, once the nephrectomy has been decided on, we must aim to procure a kidney with:

• Good perfusion.
• Artery and vein adequately preserved.
• A viable ureter.
• Minimal parenchymal injury.
• Minimal warm ischemia.

2. The three surgical goals

Three fundamental goals accompany the entire nephrectomy:

1. Minimize warm ischemia.
2. Fully preserve the vascular pedicle.
3. Maintain ureteral vascularization.

3. Before entering the operating room

The surgeon should know the donor's anatomy perfectly. Preoperative imaging should have established:

• Which kidney will be removed.
• Number of arteries.
• Early arterial bifurcations.
• Number and arrangement of the veins.
• Venous length.
• Vascular variants.
• Anatomy of the collecting system.
• Parenchymal abnormalities.

4. Which kidney do we remove?

The decision already began during the donor evaluation. The fundamental principle is: leave the donor the more favorable kidney. If there is a relevant functional difference, preserving the kidney with better function should be considered. When both kidneys are functionally equivalent, anatomy may tip the decision.

The left kidney often offers a technical advantage because of the greater length of the renal vein. But this is not an absolute rule. The presence of multiple vessels does not necessarily preclude donation either: it may require a subsequent reconstructive strategy.

5. Surgical approach

Donor nephrectomy can be performed through different approaches depending on the experience and characteristics of the center. From a teaching standpoint, regardless of the approach, the resident should understand the same objectives:

1. Expose the kidney.
2. Free it while preserving critical structures.
3. Identify the ureter and its periureteral tissue.
4. Identify the renal artery(ies).
5. Identify the renal vein(s).
6. Complete the mobilization.
7. Be prepared for immediate extraction.
8. Divide the vessels.
9. Remove it quickly.
10. Immediate cold perfusion.

6. Renal dissection

During mobilization we must avoid: capsular injury, parenchymal trauma, vascular injury, ureteral injury, and excessive dissection of the ureter. The surgery must be precise but not needlessly aggressive.

In an oncologic nephrectomy we can widely resect the tissue around the organ. In a living donor, we want to preserve the structures that will be needed for that kidney to function in another patient.

7. The ureter: less dissection may be better

This is one of the most important surgical concepts in all of transplant surgery. The graft ureter is particularly vulnerable to ischemia. That is why we must avoid "skeletonizing" it. The following should be preserved:

• Periureteral tissue.
• Periureteral fat.
• Peripelvic tissue.
• Adventitia.
• Accompanying vascularization.

Excessive dissection during procurement or back-table surgery can compromise the blood supply and later lead to ischemia, necrosis, and urinary fistula.

8. Arterial dissection

Before dividing, we must identify: the main renal artery, accessory arteries, early bifurcations, relationship to neighboring structures, and available length. CT angiography should have anticipated this anatomy for us.

An unexpected accessory artery can mean loss of perfusion to a renal segment, the need for reconstruction, and a more complex implantation. That is why prior anatomical knowledge is essential.

9. Venous dissection

The renal vein must be obtained with enough length to allow a safe anastomosis. This is particularly important in the right kidney, whose renal vein tends to be shorter. On the left side, the greater length of the renal vein can later make implantation easier, which is why —when both kidneys are anatomically and functionally equivalent— it is usually technically favorable.

10. The critical moment: vascular division and extraction

Up to this point the kidney is still perfused at body temperature. When we interrupt its blood supply, warm ischemia begins. That is why extraction must be fully coordinated. Before dividing the vessels we must confirm:

• Organ fully mobilized.
• Ureter prepared.
• Pedicle clearly identified.
• Extraction route prepared.
• Back-table team ready.
• Preservation solution available.
• Ice and necessary supplies prepared.

11. Removing the kidney

After vascular interruption:

1. Vascular division.
2. Immediate extraction.
3. Handoff to the back-table team.
4. Cooling.
5. Perfusion.

The goal is to move quickly from a warm organ with no blood flow to an organ that is adequately perfused and preserved in cold.

12. What are we aiming for with perfusion?

The conceptual goals of graft perfusion are: to clear residual blood, reduce cellular metabolism through cooling, distribute the preservation solution, detect vascular abnormalities, and prepare the organ for the cold ischemia period. Proper preservation begins immediately after extraction.

13. Back-table surgery begins

Back-table surgery is not simply "waiting while the recipient is prepared." It is a fundamental part of the transplant. Here we must:

1. Inspect.
2. Perfuse.
3. Cool.
4. Identify the anatomy.
5. Prepare the arteries.
6. Prepare the vein.
7. Preserve the ureter.
8. Correct injuries.
9. Perform reconstructions if necessary.
10. Leave the graft ready for implantation.

14. Initial inspection of the graft

Once on the back table we must check:

• Color.
• Perfusion.
• Lesions.
• Lacerations.
• Doubtful areas.

• Number.
• Length.
• Caliber.
• Lesions.
• Bifurcations.

• Length.
• Tributaries.
• Lesions.

• Length.
• Periureteral tissue.
• Integrity.
• Vascularization.

15. Perfusion: it is also a test

Homogeneous perfusion should produce adequate cooling and washout of the organ. It can also help us detect problems. For example: an area that does not perfuse suggests an unidentified arterial branch or a vascular injury; a leak of solution requires a search for a vascular injury. That is why perfusion is simultaneously: preservation + anatomical evaluation.

16. Arterial preparation

The artery should be prepared by removing only the tissue necessary to facilitate the anastomosis later. We must avoid traumatizing the intima, causing dissections, injuring branches, or needlessly shortening the vessel.

Intimal trauma during handling and back-table surgery is among the mechanisms associated with vascular complications of the graft.

17. Multiple arteries

Multiple arteries are relatively common and do not automatically mean the kidney cannot be used. They may require vascular reconstructions before or during implantation. Depending on the anatomy, it may be necessary to plan: separate anastomoses, a joint reconstruction, creation of a common ostium, or other vascular reconstructions.

In this lesson the resident does not need to memorize a single technique. The resident should understand the logic: to transform, whenever possible, a complex vascular anatomy into one that allows a safe, reproducible implantation.

18. Can every accessory artery be sacrificed?

No. Before deciding, we must consider: caliber, territory supplied, location, and the possibility of reconstruction. This is especially important for branches that take part in the perfusion of relevant territories and in the ureteral blood supply. That is why: "small artery" does not automatically mean "expendable artery."

19. Venous preparation

The renal vein should be left intact, with adequate length, without torsion, without injuries, and prepared for a technically simple anastomosis. Venous branches that need to be controlled should be handled carefully. A venous injury can turn a simple implantation into a complex reconstruction.

20. Ureteral preparation

On the back table we must again resist the temptation to "clean it up." The goal is to preserve: periureteral fat, peripelvic tissue, adventitia, and vascularization. Later, during implantation, the length needed for the urinary reconstruction will be chosen.

Another related principle: the less unnecessary ureteral length, the better the preservation of distal blood supply.

21. Warm ischemia and cold ischemia

The resident must clearly distinguish between the two concepts.

The period during which the organ remains unperfused at body temperature. It should be minimized.

The period during which the organ remains preserved at low temperature, from its perfusion/cooling until implantation and reperfusion. Cold reduces cellular metabolism and allows the organ to be preserved for a longer period.

Goal: less ischemia + less surgical trauma = better initial conditions for the graft.

Living donor approved:

Selected kidney, arteries, veins, urinary tract, variants.

Renal mobilization → ureteral identification (preserve periureteral tissue) → arterial identification → venous identification → complete mobilization.

Back-table team ready, solution ready, extraction prepared.

Warm ischemia begins → immediate extraction.

Perfusion + cooling → graft inspection (artery(ies), vein(s), ureter).

• Yes → prepare for implantation.
• No → plan/reconstruct vessels according to the anatomy.

• ☐ Did I recheck the vascular anatomy?
• ☐ Did I identify all the arteries?
• ☐ Did I properly identify the vein?
• ☐ Does the ureter retain periureteral tissue?
• ☐ Is the kidney completely mobilized?
• ☐ Is the extraction route prepared?
• ☐ Is the back-table team ready?
• ☐ Is the preservation solution prepared?
• ☐ Can we extract immediately after vascular division?

• ☐ Adequate perfusion.
• ☐ Parenchyma homogeneously perfused.
• ☐ Number of arteries confirmed.
• ☐ Arteries without obvious injury.
• ☐ Vein intact and of adequate length.
• ☐ Anatomical variants identified.
• ☐ Vascular reconstruction planned if applicable.
• ☐ Ureter intact.
• ☐ Periureteral tissue preserved.
• ☐ Graft properly cooled.
• ☐ Final anatomy communicated to the implanting surgeon.