Percutaneous nephrolithotomy (PCNL) is a cornerstone of treatment for patients with large stone burden (staghorn, stones >2 cm, or multiple stones between 1 and 2 cm), lower pole stones >1 cm, calyceal diverticular stones, or those that have failed treatment with ureteroscopy or shock-wave lithotripsy. Absolute contraindications include untreated urinary tract infection and uncorrected coagulopathy. Additionally, the surgeon must be able place the patient in prone position without cardiopulmonary compromise.
A thorough discussion of the complete preoperative evaluation is presented in the preceding chapter. We would like to emphasize the importance of a preoperative urine culture (if the urinalysis is abnormal), and a noncontrast computed tomography (NCCT) scan to visualize the stone burden and assess for complicated anatomy such as hepatomegaly or a retrorenal colon. The NCCT also identifies the diaphragm and may aid in access planning by providing a virtual roadmap of the kidney. Although we prefer to obtain our own access to optimize the tract selection, safely getting access in patients with complex anatomy may be best achieved in the interventional radiology suite with the aid of cross-sectional imaging.
Operating Room Setup and Equipment
Our typical operating room setup is shown in Fig. 27.1 . Two tables are used to set up the equipment for the procedure and we refer to these as a “lower” and an “upper” table. The lower table holds all the equipment necessary to obtain retrograde access and place a ureteral catheter ( Fig. 27.2 ). This includes a lithotomy drape, flexible cystoscope with light cord and tubing, straight hydrophilic-tipped dual durometer 0.035-inch guide wire, 5Fr open-ended catheter, several hemostats, 60-mL luer-lock syringe with diluted contrast, and extra gloves. The upper table contains the PCNL equipment ( Fig. 27.3 ), including a C-arm drape, an 18-gauge diamond-tip needle with a locking stylet, 5Fr open-ended angled-tip catheter (Kumpe catheter), hydrophilic angle-tipped dual durometer 0.035-inch guide wire, superstiff 0.038-inch guide wire, rigid nephroscope, flexible nephroscope, toothed and nontoothed rigid graspers, 30Fr/30 atm dilating balloon with sheath, and the ultrasonic lithotripter handpiece and probe. We use a PCNL drape with a central clear adhesive that allows us to obtain a seal around the patient’s back preventing fluid from running underneath the patient. It also houses a small pouch that collects the runoff irrigation ( Fig. 27.4 ). The lower table is kept next to the foot of the operating room table, and the upper table is kept parallel to the bed adjacent to the surgeon ( Fig. 27.1 ). The fluoroscopic monitor is placed near the foot of the bed, and the video tower is placed near the head of the bed, both on the side opposite the surgeon. The irrigation pole and the lithotripter unit are kept on the operative side, next to the surgeon near the patient’s head. For all PCNL cases, we have the 100W Holmium: yttrium-aluminum-garnet (Ho:YAG) laser and an electrohydraulic (EHL) lithotripter available, but we do not routinely open the disposables associated with their use until needed.
Positioning is one of the most crucial aspects of a successful PCNL. The traditional method for patient positioning is the flat prone position; however, there are other options including the deflected prone ( ) and the supine position ( ). We prefer the flat prone position with a split-leg modification ( Fig. 27.5 ), which allows the option for a retrograde approach throughout the entire procedure. We utilize a custom carbon fiber table for the procedure that contains no metal side rails near the patient’s torso so as to not interfere with the imaging during the rotation of the C-arm during percutaneous renal access ( ).
The preparation of the surgical bed is shown in Fig. 27.6 . An abundance of egg crate foam is used, with two stacks of foam supporting the patient’s abdomen, and three stacks supporting the thorax. A pillow is placed on top to ensure the patient’s back is at the same level as the head to prevent extension of the patient’s neck. All bony prominences are cushioned by foam, including the ankles, knees, and elbows.
The patient is intubated on the hospital bed and airway is secured. If the split-leg table is unavailable, the patient can be kept supine at this point, and a 5Fr open-ended catheter on the side being treated is placed and secured to a Foley catheter. The cart is elevated, and the patient is first moved to the edge of the cart, then flipped prone onto the operating table. The patient has a tendency to slide caudally during the flip, making it important to inspect the neck and make sure the pillow and foam are not compressing it. Extra foam is rolled and placed underneath the patient’s abdomen. Armrests are placed parallel to and on either side of the patient; the arms are placed in a superman position to prevent injury from excessive leaning by the surgeon. Axillary rolls should be placed and the axillary angle maintained <90 degrees to prevent brachial plexus injury. The angle at the elbow should be >90 degrees ( Fig. 27.7 ). It is important to ensure that the patient is centered on the table, because deviations can create problems when orbiting the C-arm around the patient. Both legs are abducted 45 degrees and secured to the legstand with gauze rolls. The genitalia are positioned for access with a flexible cystoscopy. In males, it is helpful to inspect the penis and pull it out from underneath the patient to facilitate prepping and cannulating the meatus ( Fig. 27.8 ). Clear the flank of any electrocardiograph leads that may have been inadvertently placed in the area of the surgical site during preoperative preparations. The entire bed is now repositioned away from anesthesia such that there is ample room in between the irrigation pole and the surgeon. The patient’s back and genitalia are now prepped (a towel is placed underneath the genitalia to maintain sterility).
The lithotomy drape from the lower table is used to cover the legs and genitalia, and the PCNL drape from the upper table is used to cover the flank. The two drapes are then clipped together with hemostats. The light cords, cameras, ultrasonic lithotripter, and irrigation tubing are then all set up and secured to the drape with hemostats to ensure they do not fall during the procedure. At this point, a surgical “time-out” and patient safety checklist is initiated before embarking on the procedure. We then begin by using the flexible cystoscope to introduce the straight dual durometer 0.035-inch guidewire into the ureteral orifice. Performing cystoscopy in prone position may be a bit challenging initially because the usual flexion and deflection points of the male urethra are now reversed. It is critically important to run the irrigation fluid through the cystoscope to ensure all the air is out of the system before passing the scope into the bladder. Filling the bladder with air can make identifying the ureteral orifices extremely difficult, if not impossible. In the bladder, the normal orientation is reversed, with the trigone and ureteral orifices located toward the ceiling, and the surgeon’s right is now also the patient’s right ( Fig. 27.9 ). As the ureteral orifice is being identified and cannulated with the guidewire, the C-arm is positioned over the kidney of interest ( Fig. 27.10 ). In order to reduce patient radiation exposure, we start the procedure with the C-arm set in “low dose” and “pulse” modes, only changing it when the image is not adequate to see the area of interest. Once the wire is advanced up the ureter, the position of the wire is confirmed with fluoroscopy. The scout film is always saved for later reference. Failure to do so can result in confusion during access if the stone can no longer be seen after the injection of retrograde contrast. With the guidewire in place, the cystoscope is removed and a 5Fr open-ended catheter is advanced up to the kidney over the guidewire. With the 5Fr catheter in place, the 0.035-inch guidewire is removed. A 16Fr Foley catheter is placed alongside the 5Fr opened-ended catheter to keep the bladder decompressed throughout the procedure. The 60-mL luer-lock syringe is connected to the open-ended catheter and secured to the drape with a hemostat. A second 60-mL luer-lock syringe is also filled with contrast and immediately available if the first one is emptied. This maneuver allows the surgeon to distend the collecting system with ease. The surgeon who placed the guidewire and catheter now changes the gloves before proceeding to the second stage of the procedure.
We find it helpful to rotate the image on the fluoroscopy monitor to make the patient’s spine horizontal across the top of the monitor, so that the plane is the same as the working plane. A scout image is always recorded prior to any contrast injection ( Fig. 27.11 ), an important step to remember because contrast may obscure the stone location later.