Editing Open Kidney Surgery (section)

=== Partial nephrectomy ===

==== Contraindications ====
* '''Patient-related issues'''
**'''Uncontrolled coagulopathy'''
*'''Cancer-related issues'''
*# '''Diffuse encasement of renal pedicle by tumor'''
*# '''Diffuse invasion of central collecting system'''
*# '''Tumor thrombus involving major renal veins'''
*# '''Adjacent organ invasion (stage cT4)'''
*# '''Regional lymphadenopathy (stage cTxN1)'''
*'''Technical issues'''
** '''Cold ischemia time > 45 minutes (consider extracorporeal approach)'''
** '''Less than 20% of global nephron mass retained'''

==== Preoperative considerations ====
* '''Hyperfiltration injury:''' when a significant portion of renal parenchyma is removed, the renal blood flow is delivered to a smaller number of nephrons, which can lead to increased glomerular capillary perfusion pressure that results in an increased single-nephron glomerular filtration rate called hyperfiltration. Over decades, the hyperfiltration can injure the remaining nephrons, resulting in focal segmental glomerulosclerosis and the clinical manifestations of proteinuria and progressive renal failure.
* '''Renal ischemia and hypothermia:''' To minimize blood loss and allow for adequate surgical visibility, it is often necessary to employ vascular compression during partial nephrectomy. Manual and clamp compression of renal parenchyma is preferable, since vascular clamping is associated with a higher incidence of renal complications. '''It is unclear whether leaving the renal vein unclamped for retrograde renal perfusion offers any tangible benefit. Attempting to limit warm ischemia to 20 minutes and cold ischemia to 35 minutes helps maintain renal function'''
* Adequate renal hypothermia (core renal temperature of 20° C) takes at least 15 minutes to achieve if the kidney is packed with ice slush. To help prevent acute postoperative renal failure, intravenous mannitol (12.5 g) and furosemide (20 mg) should be infused about 15 minutes before renal artery clamping. While evidence supporting this practice is somewhat limited, both drugs are quite well tolerated in a well-hydrated patient§§
** '''Intravenous mannitol helps prevent tissue damage by preventing cellular edema.'''
==== Summary of steps ====

===== Enucleation (for small tumours) =====

* Two cylinder shaped cigarette-like bolsters are prepared by rolling Nu-Knit Absorbable Hemostat (Ethicon, Cincinnati, OH) and tying each end with absorbable sutures. Two pledgets are prepared by folding Nu-Knit into a double-layer strip 5 to 10 cm wide and 1 cm long.
* The kidney is exposed using either the anterior subcostal or flank approach as described earlier. The entire surface of the kidney is freed of perirenal fat, with the exception of the perirenal fat overlying the tumor. While removing the perirenal fat, special care should be taken to avoid injury to the ureter, particularly for lower pole tumors.
* Intravenous mannitol and furosemide are administered and the renal pedicle is exposed sufficiently to allow safe application of a vascular clamp if necessary. Vessel loops are placed around the renal vein and artery individually.
* The renal cortex surrounding the tumor is marked circumferentially using electrocautery. The plane outside the tumor pseudocapsule and within the normal parenchyma is identified and bluntly dissected with small closed Metzenbaum scissors. For enucleation of small lesions, renal occlusion is usually not necessary. However, if there is excessive bleeding that hampers proper visualization of the resection margin, then manual compression of the kidney or clamping of the renal pedicle can help. When small vessels within the kidney are encountered they are divided sharply with scissors. The tumor is excised and the margins are examined for gross evidence of a positive surgical margin
* Small bleeding vessels in the renal parenchyma are controlled with 4-0 absorbable figure of-eight sutures on a tapered needle or by coagulation with an argon beam coagulator or bipolar electrocautery. The integrity of the collecting system is verified by checking for injury and repairing with absorbable suture if necessary.
* A Nu-Knit pledget that was prepared earlier is placed along each border of the excised renal parenchyma and in the bottom of the excised parenchyma (Fig. 60-40). The defect is closed with 2-0 absorbable horizontal mattress sutures on a long tapered 1 2 circle needle.
* If clamping was used, the pedicle is unclamped and inspection is done for bleeding, ischemia, or urine leakage of the kidney and for adjacent organ trauma. The perirenal fat and renal fascia are replaced around the kidney. A closed suction drain in the pararenal space is placed to monitor for bleeding and urine leaks. The closed suction drain is removed after 2 to 5 days when the output is minimal. A Foley catheter is used to monitor the urine output. Unless there is a large renal collecting system defect, a ureteral stent is not typically required.

===== Wedge resection (for large cortical tumours) =====

* For large tumors, intravenous mannitol and furosemide are administered, then the renal artery is clamped with a vascular bulldog clamp. Based on the surgeon’s preference, when partial nephrectomy is being performed for larger tumor sizes or lesions that are close to the renal hilum, the renal vein may also be clamped after clamping the renal artery to provide better hemostasis during partial nephrectomy. A plastic bag or sheet is placed around the kidney and filled with ice slush. The kidney is allowed to cool to 20° C (approximately 15 minutes).
* The renal capsule is circumferentially incised 5 to 10 mm peripheral to the tumor with electrocautery. Using a combination of blunt and sharp dissection with Metzenbaum scissors, the tumor is excised with a small rim of normal parenchyma. The specimen is inspected for visible tumor at the resection margin, then submitted for frozen-section analysis.
* Bleeding vessels are controlled with figure-of-eight sutures or with argon beam or bipolar electrocautery. The deep resection margin of the kidney must be inspected for any residual tumor or any sign of collecting system injury. If there is any doubt about collecting system injury, 10 to 20 mL of diluted indigo carmine is injected into the renal pelvis while occluding the ureter to assess for leaks. The collecting system is closed with 4-0 absorbable suture on a tapered needle.
* The renal parenchymal defect is reconstructed using Nu-Knit bolsters and pledgets as described above. Fibrin glue is applied to the renal parenchymal defect. Finally, the renal vessels are unclamped—if the renal vein as well as the renal artery is clamped, the renal vein is unclamped first followed by unclamping the renal artery.
* [Further details in Campbell’s]

===== Segmental nephrectomy (for large polar tumours) =====

* Intravenous mannitol and furosemide are administered and the renal pedicle is completely dissected, including the segmental branches.
* A bulldog clamp is applied to the apical segmental artery (or basilar segmental artery for lower pole tumors) and the line of ischemia is observed. The avascular line can be further demarcated by injecting 5 mL of indigo carmine directly into the clamped artery. The line of ischemia is the optimal site for transection of the kidney and should be lightly marked with electrocautery. The apical segmental artery is ligated, then the renal pedicle is clamped en bloc with a curved Satinsky clamp. A plastic bag or sheet is placed around the kidney and filled with ice slush to cool the kidney to 20° C (approximately 15 minutes). The renal capsule is incised along the line of ischemia with electrocautery. Using blunt dissection, the pole of the kidney is excised. Bleeding vessels are controlled, working expeditiously and accurately. The clamp is released to check for uncontrolled bleeders. If hemostasis is adequate, collecting system repair is begun; otherwise the pedicle is reclamped and vascular control resumed.
* The collecting system is inspected for injury. If the defect in the collecting system is large, a guidewire is inserted into the defect and manually guided into the ureter and bladder. A 6-Fr double-J ureteral stent is inserted over the guidewire with the proximal coil in the renal pelvis. The collecting system is closed with a running 4-0 absorbable noncutting suture.
* The renal capsule is closed using Nu-Knit pledgets and horizontal mattress sutures as described earlier. Because the defect is large, we use a larger needle (e.g., XLH, GS-27) for segmental polar nephrectomies and heminephrectomies than for enucleation and wedge resections. Nephropexy should be considered if the kidney is quite mobile; however, injury to retroperitoneal nerves overlying the psoas and quadratus lumborum muscles must be avoided. The kidney is covered with perirenal fat and renal fascia and a closed suction drain is placed to monitor output postoperatively. The indwelling Foley catheter is removed when the patient is mobile and stable. Depending on the output of the closed suction drain, it can be removed 5 to 10 days postoperatively. If a ureteral stent is used, it should not be removed for 4 to 6 weeks postoperatively. After removal of the indwelling Foley catheter, if the output of the closed suction drain is increased, the transurethral indwelling Foley catheter is reinserted to reduce the intrapelvic urine pressure, which should minimize the output from the closed suction drain.

==== Post-operative care ====

* A retrospective cohort study of 154 patients undergoing partial nephrectomy for kidney cancer found that '''patients that received ketorolac had an earlier return to solid diet and earlier discontinuation of patient controlled analgesia, and no difference in serum creatinine, blood loss, transfusion rates and complication rates,''' compared to patients that did not receive ketorolac[https://pubmed.ncbi.nlm.nih.gov/14767271/].

==== Complications ====

* '''Urinary fistulae'''
** PNs that involve of the collecting system increase the possibility of urinary leakage.
** Most urinary fistulae present themselves in ≈1 week postoperatively; in cases of deep renal resections, it is advisable to keep the closed suction abdominal drain in place for 7-10 days.
** '''In the case of an unrecognized or delayed urinary leak, the presence of an adjacent urinoma will prevent fistula closure and predispose the patient to infection/abscess formation.'''
*** '''Percutaneous drainage of the urinoma is the preferred method used to control an unrecognized or delayed pyelocutaneous fistula.'''
**** To further maximize drainage, consider a double-J ureteral stent that is placed after retrograde pyelography and (3) a Foley catheter to keep the entire collecting system at low pressure.
*** Most fistulas resolve within 4 to 6 weeks with conservative management, and reoperation is rarely required.
* '''Postoperative bleeding'''
** Delayed bleeding can occur following partial nephrectomy
** Usually, bleeding segmental and subsegmental arteries can be selectively embolized and the kidney salvaged without need for complete nephrectomy.
** Life-threatening hemorrhage can also occur and require complete angioinfarction of the kidney or reoperative exploration.
* '''Renal insufficiency'''
** While most cases of postoperative renal insufficiency are mild and temporary, some cases require hemodialysis for electrolyte and fluid management. Hyperfiltration injury can also cause a gradual decrease in renal function over time, typically associated with proteinuria.
** The medullary thick ascending limb of Henle is most sensitive to ischemic damage.