I. Treatment of tumor resection scope and positive cut edge
For radical nephrectomy, if the tumor is close to the upper pole of the kidney or invades the ipsilateral adrenal gland, the adrenal gland can be considered to be removed together. For partial nephrectomy, the extent of tumor resection and the management of positive margins should be considered. Previous studies suggested that the resection margin should be 5-10 mm away from the mass, but the greater the distance, the more kidney units will be removed and the risk of complications such as damage to the collecting system and bleeding increases. Currently, it is considered ideal that the tumor is 5 mm away from the incisional margin, but a distance of 1~2 mm is sufficient to meet the negative rate of the incisional margin. When performing partial nephrectomy, cold knife resection is used as much as possible, with clear levels and easy to identify the boundary between normal kidney tissue and tumor.
For cases with intact normal kidney tissues encircling the cut margin by visual observation, intraoperative routine cryopathological examination is not necessary. If the postoperative margins are positive, close follow-up or radical nephrectomy can be considered. Some literature suggests that positive surgical margins do not seem to increase the long-term risk of local recurrence and distant metastasis, i.e., positive margins in partial nephrectomy specimens do not always mean a poor prognosis.
II. Management of renal tumors in different locations
The factors affecting partial nephrectomy are not only related to the size of the tumor, but also the location of the tumor is crucial, and the more specific ones are hilar tumor and central tumor.
1.Hilar tumor
Hilar tumor refers to the tumor whose edge is less than 5mm from the hilar vessels. This type of tumor is closer to the renal blood vessels, so the risk of surgery is higher. Up to now, the following matters should be noted for this type of surgery.
①Pre-operative perfect renal enhancement CT+CTU+CTA to understand the number of branches of renal hilar vessels, the adjacent relationship between the vessels and the tumor and the depth of the tumor;
(2) The renal hilum and surrounding area should be fully freed during surgery, and if necessary, additional puncture cannula should be used to pull the perirenal fat so that the tumor, renal vessels and collecting system can be clearly revealed to avoid injury;
(iii) The renal hilum should be freed as long as possible, and laparoscopic vascular blocking forceps should be placed away from the hilum in order to preserve sufficient operating space at the hilum;
④Attention should be paid to avoid rupture and bleeding of the tumor trophoblastic vessels during the separation of the tumor from the renal hilum;
⑤ Most of the hilar tumors are adjacent to the collecting system, so it is easy to suture the renal blood vessels and damage the collecting system during surgery. The key point of resecting such tumors is to separate the renal blood vessels around the tumor firstly, and the direction of the needle should be passed outward from the hilar when suturing;
(6) The laparoscopic ultrasound probe can be applied for intraoperative tumor localization to understand the depth of tumor and its boundary with normal renal parenchyma, so as to avoid excision too deep and damage to blood vessels and collecting system;
(7) The suture of renal parenchymal wound should not be too deep to avoid forming arteriovenous fistula or suture of renal artery or ureter to form arterial stenosis or hydronephrosis.
2.Central tumor
Central tumor is a tumor that is completely or mostly buried in the renal parenchyma, and the outline of this type of tumor cannot be seen directly during surgery. If too little tissue is removed, positive margins may occur; if too much tissue is removed, too many kidney units will be lost, and the collecting system and even small renal vessels may be damaged, resulting in excessive bleeding and urinary fistula. Preoperatively, CT examination should be improved to find the location of tumor according to CT reconstruction, and intraoperative ultrasound should be used to clarify the location and resection range of tumor, and ultrasound can also determine whether there are satellite foci.
After the tumor location and boundary are clearly identified, the tumor is marked by electrocautery at the edge of the mass with ultrasound knife, the ultrasound probe is removed, the renal artery is blocked with laparoscopic arterial blocking forceps, and the tumor is wedge-shaped resected along the mark at 0.5 cm from the tumor edge, which is often easy to cut to the tumor envelope and the resection range needs to be readjusted to ensure complete resection of the tumor, and the renal pelvis and renal parenchyma are continuously sutured in layers.
For this type of tumor.
①Pre-operative enhancement CT examination of the kidney should be completed to have a good understanding of the relationship between the tumor and surrounding vessels and the number of vascular branches supplying the tumor;
(2) Ultrasound must be used for positioning during surgery to accurately remove the tumor and preserve the kidney unit to the maximum extent;
③The difficulty of surgical operation is related to the location of the tumor. Those relying on the dorsal side are mostly accessed through the posterior abdominal cavity, while those relying on the ventral side of the kidney can be accessed through the abdominal cavity;
④Suture in two layers, the first layer is continuously sutured with 3-0 absorbable thread, the end of the thread is knotted and a Hem-o-lok is clamped close to the knot in the direction of the needle, the thread should be tightened for each stitch, and it is better to repeat the suture at the bleeding area to reduce bleeding; the second layer is continuously sutured to the renal parenchyma; after releasing the arterial clamp, the head and tail of the two layers of sutures are then pulled towards the outside of the kidney to reduce intraoperative and postoperative bleeding and the formation of pseudoaneurysm;
⑤ If the tumor is close to the collecting system, the ureteral stent tube can be left in advance;
⑥The technique of such surgery is demanding, and it is better to complete a certain number of laparoscopic partial nephrectomy before doing central tumor.
Prevention and treatment of surgical complications
Whether laparoscopic radical nephrectomy or laparoscopic partial nephrectomy for kidney cancer, some complications may occur. The following will discuss some common complications management.
1.Peritoneal injury
The most common reason is that the peritoneal gap is not large enough after balloon expansion and does not exceed the puncture point, and the placement of trocar needle in the anterior axillary line position is caused by penetration into the peritoneal cavity; the second reason is that the peritoneum is damaged when separating the kidney medially. When freeing the kidney, we must pay attention to the anatomical signs and separate between the lateral cone fascia and fat capsule to avoid damaging the peritoneum. If the peritoneum is damaged, titanium clamps or Hem-o-lok clamps can be used to close it, or pneumoperitoneum needles can be inserted under the costal margin in the peritoneal cavity to release the intra-abdominal gas; or a 5mm Trocar can be added 3cm above the anterior superior iliac spine and instruments can be placed to block the peritoneum.
2.Vascular injury
Be sure to look carefully at the CT film before surgery to understand the number and location of the branches of the renal arteries and veins. If intraoperative renal vein or vena cava tear occurs, the pneumoperitoneum can be modulated by 20 mmHg, and titanium clamps can be applied to close it or 5-0 vascular suture can be used to stop the bleeding under lumpectomy; the confluent branch of the left renal vein often has a variation, and there is often a traffic branch between the lumbar vein and the collateral vein below the renal vein trunk, and this vein is often close to the renal artery, so the outer membrane of the renal artery can be opened, and the vein can be separated with curved forceps close to the renal artery to avoid damage to the vein, or titanium clamps or Hem-o-lok clamps are used to close this vein and cut it off. When freeing the artery, if there is bleeding from a small branch of the renal artery, use ultrasonic knife coagulation or compression to stop the bleeding. It is important to remain calm when dealing with vascular injury, while paying attention to volume replenishment and deciding whether to transfuse blood according to the situation.
3. Bleeding from trauma and urinary leakage
This condition is mainly seen in partial nephrectomy and depends on the closure and hemostasis of the collecting system. It is important to suture the collecting system exactly during the operation and then suture the renal parenchyma in one layer. Our experience is to open the renal artery after suturing, and at the same time lower the pneumoperitoneum pressure to see if there is bleeding, if there is obvious bleeding, first tighten the head and tail of the second layer of sutures again, add pressure to stop the bleeding for 5 min, if there is still obvious bleeding then suture the bleeding area, after tight hemostasis, you can spray bioprotein glue on the wound surface and cover it with hemostatic gauze, leave the drainage tube; it is better not to use bioprotein glue in the lower pole of the kidney, this glue can cause ureteral If ureteral stenosis occurs, dilatation with a rigid ureteroscope is sufficient.
Postoperatively, the drainage should be observed, and if the drainage is high, conservative treatment is preferred; if the effect is not good, interventional embolization should be considered to stop the bleeding; if urinary leakage occurs after surgery, the drainage tube should be kept open and waiting for the healing of the collecting system.
In conclusion, laparoscopic technique has obvious advantages in the management of renal tumors with satisfactory therapeutic effects. Although technically more difficult and some complications exist, these problems will be solved with the development of technology. At present, 3D laparoscopic technology has emerged, which can give the operator 3D vision, making the operator more exact in the grasp of depth and more convenient in the process of dealing with blood vessels and suturing. It is believed that the development of surgical techniques and the improvement of surgical refinement will bring benefits to more and more patients.