7 Day 6: Exercises: Kidney Autotransplantation, Supermicrosurgery, and Aneurysm Clipping

10.1055/b-0040-177321

7 Day 6: Exercises: Kidney Autotransplantation, Supermicrosurgery, and Aneurysm Clipping

Evgenii Belykh and Nikolay L. Martirosyan

Abstract

In the later stages of microsurgical training, when your skills are plateauing, challenging yourself with a complex microsurgical procedure can further improve your abilities. In this chapter, we present the concept of supermicrosurgery and a rat kidney autotransplantation exercise to help develop necessary tissue handling and anastomosis skills. We also provide an introduction to aneurysm clipping.

7.1 Exercise: Kidney Autotransplantation

Kidney transplantation in a rat is a technically demanding exercise that microsurgeons are often required to master. This exercise consists of three anastomoses: arterial, venous, and ureteral. In this case, a kidney may be transplanted to either the femoral vascular bundle or the aorta (Fig. 7.1).

Renal autotransplantation is a time-consuming staged procedure that requires good anastomosis skills, respectful tissue handling, and advanced planning (Fig. 7.2). To begin the procedure, a median laparotomy is performed. The left kidney is then identified, and the ureter is found by its peristaltic movements and is dissected bluntly. The pararenal soft tissues are removed, and the renal vascular pedicle is thoroughly dissected to prepare the vessels for anastomosis. Proximal clips are applied, and the vessels are cut, leaving a stump that is long enough to allow anastomosis to be performed. The ureter should be cut near the distal end. Next, the kidney is perfused through the renal artery with ice-cold normal saline. First, the renal vein is anastomosed in the end-to-side fashion, and then the arterial anastomosis is performed using the same technique.

**Fig. 7.1** Illustration showing kidney autotransplantation. **(a)** Left kidney is harvested; *dashed lines* indicate the location of the incisions. **(b)** Kidney may be anastomosed to the femoral vessels or aorta and vena cava. The *black bars* indicate the location of the ureter incisions.

**Fig. 7.2** Stepwise illustration of kidney autotransplantation. **(a)** The right kidney is exposed, revealing a short vascular pedicle. **(b)** In both rats and humans, the left kidney has a longer vascular pedicle than does the right kidney. **(c)** The left renal artery, vein, and ureter are dissected. **(d)** The aorta and vena cava segments are dissected in preparation for anastomosis. **(e)** The kidney is washed with ice-cold normal saline, the renal artery and vein are cleaned of adventitia, and the kidney parenchyma has become pale. **(f)** The aorta and vena cava are clipped, and the front wall of the venous anastomosis is finished first, leaving space for the arterial anastomosis between the clips. **(g)** The venous anastomosis is checked from the inside, and then the back wall is sutured. **(h)** The arterial anastomosis is created at a different level than the venous anastomosis for convenience. **(i)** The clips are removed, and blood flow is restored. **(j)** Note that the kidney parenchyma regains a red color after restoration of blood flow. **(k)** The ureter is inserted into the bladder through a small incision and fixed with a pair of sutures. Peristalsis should be observed (Video 7.1).

7.2 Exercise: Supermicrosurgery to Create a Free Groin Flap with the Vascular Pedicle

Supermicrosurgery is defined as the technique employed in the anastomosis of vessels less than 1 mm in diameter. ¹ This surgical technique allows surgeons to perform vascularized flap transplantation, fingertip transplantation, lymphovenous anastomoses for edema treatment, and experimental studies on the transplantation of vascularized tissues and organs in laboratory animals. In neurosurgery, anastomoses are performed on vessels of such small diameters for the treatment of moyamoya disease in children. The performance of supermicrosurgery requires instruments with ultrasmall tips (e.g., 0.06-mm forceps tips compared with the average microsurgery forceps tips of 0.15 mm), 0.05-mm needles (12–0), and a special operative microscope with 50x magnification ² (Fig. 7.3).²

**Fig. 7.3** **(a)** Sutures, needles, and **(b)** forceps used for supermicrosurgery (*yellow arrows*) and microsurgery (*black arrows*). (Reproduced with permission from Mihara et al.²)

Finding small vessels with a diameter of less than 1 mm for practice is easy in many animal models. One classic example used for supermicrosurgical training is the creation of an epigastric artery flap. ³ In this exercise, a rat is anesthetized and positioned for surgery. A skin flap approximately 3 × 3 cm is dissected out and elevated on the vascular pedicle containing the inferior epigastric artery (0.3–0.4 mm in diameter) and vein (0.6–0.8 mm in diameter). These vessels arise from the femoral vessels approximately 1 cm distal to the inguinal ligament. To avoid twisting of the vascular pedicle, inferior epigastric vessels should not be freely dissected from the surrounding tissues. The vascular pedicle is treated with 2% lidocaine and kept in moistened gauze for 20 minutes, which decreases vascular spasm. ¹ After the flap vitality is confirmed, the vessels are cut, and the blood is carefully removed from the flap by perfusing the flap with the ice-cold heparinized normal saline. The vessel stumps are washed with a heparinized solution and prepared for end-to-end anastomosis. Ultrasmall 11–0 or 12–0 sutures are used to create the anastomosis on such small vessels, employing greater than 25x magnification. Four sutures are usually sufficient for an arterial anastomosis, whereas 6 sutures are necessary for a venous anastomosis. After the anastomosis is checked for patency, the skin flap is sutured back in place. In this survival experiment, the quality of the anastomosis is assessed daily until the wound is healed or the flap is rejected.

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