Open Stone Surgery: Anatrophic Nephrolithotomy and Pyelolithotomy





Introduction


The treatment of renal calculus disease has changed dramatically over the past few decades with the introduction of new and advanced endoscopic and percutaneous techniques. Open techniques for management of renal and ureteral calculi have been used for more than 50 years. Anatrophic nephrolithotomy was first described by . Their description involved creating a nephrotomy in the relatively avascular plane of the kidney in order to prevent damage to the vasculature and avoid renal atrophy. Hence, this procedure was given the name anatrophic. Treatment for such large stones is typically advocated because of the significant morbidity and mortality associated with large staghorn stones. Blandy (Blandy 1976) published that patient survival is reduced in the presence of a staghorn stone, with a mortality of 28% in 10 years. The American Urological Association guidelines recommend PCNL as the first line of treatment for staghorn renal stones (Assimos 2016) and state that open surgery should be reserved for cases when endourologic procedures are not suitable or have failed. Nevertheless, there is a small subset of patients with extremely large staghorn stones not amenable to percutaneous procedures. An even smaller number of patients are candidates for open pyelolithotomy, which is also described ( ). A laparoscopic approach for anatrophic nephrolithotomy, initially described in a porcine model in 2003 ( ), and robot-assisted laparoscopic nephrolithotomy, initially reported in 2013 ( ) can be currently considered alternatives to open surgery; nevertheless, the open procedure remains the preferred approach when less invasive endourologic treatments are not feasible. Both anatrophic nephrolithotomy and pyelolithotomy may be performed more commonly in centers when percutaneous or endoscopic equipment is not readily available.




Anatrophic Nephrolithotomy


Preoperative Planning and Preparation


All patients should be evaluated with three-dimensional reconstruction of noncontrast computed tomography of the abdomen to understand the spatial orientation of the renal anatomy and stone. If there is concern about the function of the kidney, a nuclear medicine renogram should be performed. All patients undergoing stone surgery should have a preoperative urine culture performed. If positive, oral culture–specific antibiotics should be started 7 days prior to surgery. If urine culture is negative, a consideration should be given to starting a broad-spectrum antibiotic 7 days before surgery as a significant number of these complex stones may be colonized with bacteria. Intraoperative antibiotics should cover known urine organisms and be broad spectrum because of known discordance between bladder urine cultures and renal pelvic urine/stone cultures. All patients should have basic labs preoperatively including creatinine, as well as a type and screen. All patients should be managed under general anesthesia.


Patient Positioning and Surgical Incision


A Foley catheter is placed. Sequential compression devices are placed on both legs. The patient is placed in the 90-degree flank position with the affected side up. The table is flexed to open up the space between the ribs and the iliac crest. An axillary roll is placed to protect the brachial plexus. The contralateral arm is placed perpendicular to the body and the ipsilateral arm is placed in an Allen armrest. The bottom leg is bent and the top leg is straight. All pressure points are padded with foam. The patient is secured to the bed with foam and Velcro straps. A beanbag can also be used to help secure the patient’s position.


A flank incision is used to access the kidney. An 11th or 12th rib incision is made depending on the location of the kidney. The pleura and diaphragm are mobilized cranially, and the peritoneum is mobilized medially. Resection of the tip of the 12th rib is usually unnecessary. Resection of the 11th rib may be necessary if the kidney is located high in the retroperitoneal cavity ( Fig. 24.1 ).




FIGURE 24.1


Patient positioning in the flank position with the table flexed. Incision is made at either the 11th or 12th rib.


Operative Technique


The Gerota fascia is encountered and opened in a cranial-caudal fashion over the posterior aspect of the kidney to allow for covering at the time of closure. The kidney is fully mobilized; perinephric fat is dissected off the kidney taking care not to enter a subscapular plane. Superior dissection must be performed gently to separate and free the adrenal gland and inferior dissection to separate the lower pole. Each renal pole should be free to facilitate dissection and further manipulation of the renal hilum ( Fig. 24.2 ). The renal hilum is identified and the ureter, renal artery(ies), and renal vein(s) are surrounded with vessel loops. The posterior segmental branch of the renal artery is typically dissected as it courses around the posterior aspect of the renal sinus.




FIGURE 24.2


Gerota fascia and perinephric fat is dissected free exposing the capsule of the kidney.


At this point, an intraoperative plain film or fluoroscopy can be performed to help with planning the optimal location for nephrotomy. Intraoperative ultrasound may also be used to facilitate stone location and help to direct nephrotomy.


The posterior segment is then temporarily clamped with a bulldog clamp or rubber shod, and the patient is given 10–20 mL intravenous methylene blue. This will result in blanching of the posterior segment of the kidney, the blue-colored parenchyma allowing delineation of the avascular intersegmental plane, that is, the Brodel line. This plane is marked using Bovie electrocautery on the capsule. Once marked, the clamp on the posterior segmental artery is removed ( Fig. 24.3 ).




FIGURE 24.3


The avascular plane is identified and marked using Bovie electrocautery.


The kidney is then surrounded by a plastic drape, 12.5 g of mannitol is given intravenously, and 10 minutes later the renal hilum is clamped using bulldog clamps or a vascular clamp. Once clamped, the kidney is covered in ice slush for 10 minutes to achieve a parenchymal temperature of 15° C. Ice slush should be replaced at least every 30 minutes while clamped ( Fig. 24.4 ).




FIGURE 24.4


The renal hilum is clamped, and the kidney is cooled for 10 minutes.


Incise the capsule sharply along the previously marked line, even if it is irregular. Make the incision as short as deemed necessary, it can always be opened up later. Using a Penfield dissector or the back of a scalpel, bluntly separate the parenchyma until the collecting system is encountered ( Fig. 24.5 ). Take care not to dissect into the poles of the kidney. Sharply transect any interlobar vessels encountered; few should be seen if in the appropriate avascular plane.




FIGURE 24.5


The avascular plane is incised and a Penfield dissector or a scalpel handle is used to dissect the renal parenchyma.


Open the collecting system sharply with a Potts scissor and expose the stone ( Fig. 24.6 ). Use the Potts scissors to open calyces to access all ramifications of the stone. Once the stone is exposed, gently free the stone with a blunt Randall forceps ( Fig. 24.7 ). Complex stone ramifications or stones located in calices with stenotic infundibulum may require a separate nephrotomy incision directly over the moiety where the stone is located; this may decrease extension of the main incision and prevent injury to a segmental arterial branch ( Fig. 24.8 ). Inspect each calyx in succession and gently palpate the renal parenchyma to ensure all stone is removed. A nephroscope (flexible cystoscope or ureteroscope) can be used to ensure all calyces are free of stone. Once all stone is removed, repeat intraoperative plain-film imaging or fluoroscopy can help identify any residual stone. Once the bulk of the stone has been removed from the renal pelvis, an antegrade ureteral stent is placed over a glide wire to help prevent any migration of stone particles. This stent will remain in place after closure.




FIGURE 24.6


The collecting system is opened sharply over the stone using a Potts scissors or scalpel.

Jan 2, 2020 | Posted by in UROLOGY | Comments Off on Open Stone Surgery: Anatrophic Nephrolithotomy and Pyelolithotomy

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