Preoperative Preparation and Planning
Percutaneous resection of upper tract urothelial carcinoma enables larger-caliber instruments than ureteroscopy, which allows for improved tumor sampling and staging. Nephroureterectomy is recommended for high-grade tumors, invasive tumors, or high-volume tumors with a healthy contralateral kidney. Percutaneous resection is recommended for low-grade tumors where retrograde endoscopic management is not feasible and especially in the presence of a solitary kidney, chronic kidney disease, or bilateral tumors. Surgical planning and targeting of the involved calyx enables access with a continuous-flow resectoscope for efficient removal of high-volume tumors. Also, a nephrostomy tube allows for antegrade instillation of topical adjuvant treatments. Downsides to percutaneous treatment include increased risk of significant bleeding, an overnight stay, and the risk of nephrostomy tract seeding and tumor implantation.
A full medical history and physical is recommended to assess for bleeding disorders and cardiac and pulmonary disorders that could be compromised by prolonged prone positioning. Antiplatelet agents should be held for 7 days prior to the surgery. A urine culture is required and any infection cleared prior to surgery. A complete blood count and basic metabolic panel should be included to assess cell counts and renal function. A computed tomographic (CT) urogram or retrograde pyelogram is important for targeting the correct calyx of entry. The CT scan is also used to ensure the colon and other adjacent organs are outside the intended percutaneous tract.
Patient Positioning and Surgical Incision
The patient starts in the dorsal lithotomy position for cystoscopy. A 5F open-ended stent is placed under fluoroscopic guidance into the involved kidney to enable retrograde opacification of the system during percutaneous access. Finally, the patient is placed in the prone position, with the arm of the affected side flexed at the elbow and placed on an armrest. The contralateral arm can be tucked at the patient’s side. A bump is placed under the chest so that the neck is not extended. All pressure points should be adequately padded. The skin incision is generally slightly inferior and medial to the tip of the 12th rib for lower pole access and should be chosen with fluoroscopic guidance. Alternatively, the patient can be placed initially in a prone position with the hips abducted on spreader bars. Retrograde and antegrade access can be maintained throughout the operation. Retrograde ureteroscopy in addition to percutaneous access is particularly useful when all tumors cannot be accessed through a single percutaneous access.
Nephrostomy Tract Access
It is critical to select the appropriate calyx of entry. For renal pelvis tumors, midpole access is preferred. Lower pole access for renal pelvic tumors requires maneuvering an acute angle, which may preclude resectoscope usage. Upper pole access provides good access to the renal pelvis and upper ureter, but should be approached cautiously to minimize the risk of trans-pleural nephroscopy, hydrothorax, and tumor seeding. For posterior calyceal tumors, direct access to the affected calyx is recommended. For anterior calyceal tumors, it may be easier to get posterior access in the opposite pole of the kidney. Fig. 14.1 shows access selections for upper pole, lower pole, and renal pelvis tumors. The 5F open-ended ureteral catheter or a ureteral balloon occlusion catheter is used to inject 5 mL of radiopaque contrast to define the collecting system. An 18-gauge diamond-tipped needle is used under fluoroscopic guidance to access the chosen calyx using either the eye of the needle or triangulation technique. The tract is dilated to 30-French using either balloon or sequential dilation. For a detailed discussion on percutaneous techniques see the chapter on Percutaneous Renal Access .
Properly aligned access allows for the use of rigid instruments. Fig. 14.2 shows tumor removal with the cold biopsy cup in a piecemeal fashion. A thorough biopsy from the base of the tumor is important for staging. Larger tumors are more easily resected with a continuous-flow resectoscope using a technique similar to transurethral resection of bladder tumors. Continuous-flow resectoscopes have a standard working length near 20 cm, but working lengths near 26 cm are available for obese patients. The skin tumor distance can be estimated on the preoperative CT scan to ensure that the proper resectoscope is available. High intrarenal pressures should be avoided by ensuring adequate outflow through the access sheath. Fig. 14.3 shows a resectoscope with loop electrocautery. The use of loop electrocautery allows for efficient removal of larger tumors and staging. Minimal energy settings should be used to reduce collateral damage and risk of perforation in the kidney. As soon as a tumor fragment is detached, it should be collected for pathology prior to further resection. Immediate tumor removal also helps to minimize tumor spillage downstream or outside the collecting system. Small swipes are recommended to avoid renal perforation, which is a significant risk when using cutting current on the renal pelvis. A rollerball may be helpful to ablate the base of a tumor resection. For tumors adjacent to the calyx of entry, laser energy can be used with flexible nephroscopy for ablation ( Fig. 14.4 ). A holmium:YAG laser familiar to urologists for stone fragmentation can be used ( ) at energy settings of 1.0–1.5 J and frequency of 6–10 Hz. One advantage of the holmium:YAG laser is that it can be used with normal saline irrigation. The Neodymium:YAG laser has deeper tissue penetration and is potentially more dangerous. Alternatively, papillary tumors can be snared using a stone basket such as the 2.2F Nitinol basket from Boston Scientific or gastrointestinal snare.