Pyelolithotomy

The term pyelo means renal pelvis, and the term lithotomy means removal of stone. Since the advent of extracorporeal shockwave lithotripsy (ESWL) and percutaneous nephropyelolithotomy (PCN), pyelolithotomy has become an uncommon surgery in most developing countries. However, before these newer technologies, pyelolithotomy was the procedure of choice for stones within the renal pelvis, including stones that demonstrated minimal invasion into calyces and infundibulum. Pyelolithotomy differs from an anatrophic nephrolithotomy, as the anatrophic nephrolithotomy allows for greater access to calyces and allows for repair of infundibulum and calyces. Anatrophic nephrolithotomy is indicated for large multiple-branched staghorn calculi with infundibular stenosis.

ESWL is clearly noninvasive, but it may necessitate (1) a cystoscopy and the insertion of a stent to drain the kidney or (2) a nephrostomy in some cases involving infection. ESWL is associated with less morbidity than pyelolithotomy, but the overall failure rate and the amount of residual stone fragments are higher. Lower pole stones fragments do not flush out of the renal unit as readily as midpole and upper pole fragments.

PCN is a highly technical procedure and requires some experience for optimal results. At some facilities, these procedures require the teamwork of a radiologist and a urologist. Morbidity is higher than with ESWL, but residual stone fragments are less common. The stone-free rate associated with percutaneous nephrolithotomy (PNL) is 90%; ESWL, 54%.

The 2004 American Urological Association (AUA) guidelines recommend that staghorn smaller than 2500 mm2 with normal renal anatomy should be treated with PNL as first-line treatment and with ESWL as a follow-up procedure.

Pyelolithotomy continues to have a role in the management of renal pelvic stones in areas where ESWL and PNL are not feasible because of the lack of equipment or expertise. 

Indications for pyelolithotomy include minimally branched staghorn stones in the renal pelvis of complex collecting systems and excessive morbid obesity. Pyelolithotomy is also appropriate in patients who are undergoing major open abdominal or retroperitoneal surgical procedures for other indications; the most common concomitant procedure is open pyeloplasty for ureteropelvic junction (UPJ) obstruction.

On October 8, 1872, Ingalls performed a nephrotomy at Boston City Hospital. In 1880, Henry Morris, an English surgeon, performed the first pyelolithotomy on a 31-year-old woman. Vincenz Czerny also performed a pyelolithotomy in 1880. These initial operations were performed without regard for renal vasculature, anatomy, or functionality. The technique was refined after Gil-Vernet better described renal vascularity and function of the collecting system musculature.[1] The incision of the renal pelvis was initially taken vertically but, after Gil-Vernet's description, became a transverse incision, therefore preserving anatomic musculature and blood supply.

Patients may be asymptomatic or may present with symptoms that include renal colic, flank pain, sepsis, and/or hematuria. In addition, incidental findings of stones on a CT scan or during laboratory workup studies that demonstrated an elevated creatinine level have followed with a finding of partially obstructive stones within the renal pelvis.

Pyelolithotomy is a surgical procedure in cases involving a stone in the renal pelvis. This was a common procedure until the development of extracorporeal shockwave treatment, PNL, and ureteroscopic laser lithotripsy. However, pyelolithotomy continues to be performed when other modalities fail or when proper facilities are unavailable.

Although it is now considered overly invasive for routine use, pyelolithotomy continues to have a role in select cases. Criteria include the size of the stone,[2] the need for concomitant open surgery, and an inaccessibility to ESWL or PCN. Current guidelines advocate pyelolithotomy or anatrophic nephrolithotomy when the stone burden is greater than 2500 mm2, in cases of extreme morbid obesity, or when the patient presents with a complex collecting system.

Other indications are relative and include failure of stone clearance via PCN, ureteroscopy, or ESWL owing to difficult extraction, stone composition (ie, cystine), or anatomy (ie, ectopic, pelvic, or horseshoe kidney). Pyelolithotomy is also indicated in combination with pyeloplasty, without increasing morbidity or decreasing the success rate.[3]

Indications for stone removal (possible pyelolithotomy) include sepsis, severe flank pain, obstruction with impending parenchymal renal loss, and hematuria. Patients who present for pyelolithotomy also meet the criteria as outlined above.

The renal pelvis is posterior to the hilum of the kidney. From anterior to posterior, the relationship of the structures is renal vein, renal artery, and pelvis.

The pelvis can be extrarenal or intrarenal. In an intrarenal pelvis, the pelvis is embedded in the parenchyma of the kidney. An extrarenal pelvis is exposed outside of the parenchyma and is easily reachable. The renal pelvis joins the ureter at the UPJ. Normal pelvis volume is 3-5 mL.

On the left side, the ovarian vein or testicular vein is adjacent to the ureter and pelvis. Recognize and identify these veins during surgery to avoid injury and bleeding.

Pyelolithotomy is absolutely contraindicated in patients in a poor general medical condition. Only consider this surgery when all other options fail.

Relative contraindications include branched staghorn calculi with infundibular stenosis and stones in the calices. These conditions may be approached using the Boyce anatrophic nephrolithotomy or calycelectomy.

The usual surgical profile includes the following:

• Complete blood cell (CBC) count

• Blood type

• Activated partial thromboplastin time and prothrombin time

• Electrolytes

• Blood urea nitrogen

• Creatinine

In addition, perform a urinalysis (with culture and sensitivity).

Confirmation is usually based on radiologic findings from the following studies:

• A radiograph of the kidneys, ureters, and bladder (KUB): Ninety percent of stones are radiopaque.

• A CT scan provides information to quantify stone mass. This also shows uric acid stones, which are radiolucent. It also assists in outlining renal pelvic anatomy anthe presence location of the stone within the collecting system. It also helps with identification of vascular anatomy. It is critical prior to performing a pyelolithotomy.

• An intravenous pyelogram (IVP) provides information on collecting system anatomy, demonstrating filling defects where stone burden is located. This also shows uric acid stones. See the image below.

  Intravenous pyelogram demonstrating ureteropelvic junction obstruction with dilatation of the collecting system and lack of excretion of contrast.

• Cystoscopy and a retrograde pyelogram offer similar information as IVP and are performed when patients have renal failure, usually with a creatinine level of more than 1.8 g/24 h. See the image below.

  Retrograde pyelogram demonstrating ureteropelvic junction obstruction secondary to annular stricture.

• Renal scintigraphy should be considered in patients with a large stone burden and long-standing obstruction. The kidney function in this clinical scenario can be extremely poor, and, if confirmed on functional study, a nephrectomy may be more appropriate.

Perform a renal scan to confirm function of the kidney in question if renal atrophy is noted.

Prior to surgery, if the nature of the infecting organism is known, use the appropriate intravenous antibiotic based on culture results. If culture results are not available, use a broad-spectrum antibiotic. Assume all candidates for open pyelolithotomy are or will be infected at the time of surgery because renal pelvic stones tend to harbor bacteria.

The goal of the preoperative evaluation includes improving the patient's general condition as much as possible, especially if sepsis is present. In a septic patient, drain the kidney using a stent or via nephrostomy. Let the kidney rest for 48-72 hours, if possible, so that the inflammation from the infection subsides. A less inflamed kidney is less friable and bleeds less.

A stent is not required but may aid in ureteral identification if in place. In addition, a stent prevents stone fragments or debris from blocking the ureter. Even though the renal pedicle is generally anterior to the renal pelvis, at times a posterior branching blood vessel may be present. Approaching the renal pelvis posteriorly is easier. Infected urine can be drained posteriorly using a retroperitoneal drain.

The left-sided testicular or ovarian vein may resemble the ureter. When in doubt, feel for the stent or aspirate with a 22-gauge needle and syringe.

Properly positioning the patient is key for easier surgery. Be prepared to perform an extended pyelotomy. Always dissect the upper and lower poles of the kidney and renal pedicle or, at least, be prepared to do so.

A pyelolithotomy can be performed as an open, laparoscopic,[4]  or robotic[5, 6]  procedure. The approach can be transperitoneal or retroperitoneal. 

Use endotracheal general anesthesia. Insert a Foley catheter. Consider placing a ureteral stent to aid in identification of the ureter.

During renal pelvis dissection, it is important to adequately expose the renal pelvis and identify all surrounding vascular branches and the ureteropelvic junction (UPJ).

A vertical incision should be made. Consider placing stay stitches at the apex of the pyelotomy to avoid extension into the infundibula. Extension into the calyces can occasionally be required. Graspers should be used to grasp the stone and extract it intact if possible. Stones should be counted as they are removed to ensure that all stones noted on preoperative imaging were removed. Irrigate the pyelotomy with normal saline to eliminate stone debris. Thorough inspection for residual stones can be performed by inserting a flexible cystoscope or ureteroscope and directly visualizing all calyces. An endoscopic basket can be used to grasp residual stone fragments. The pyelotomy can then be closed using an absorbable suture. Urinary drainage with a ureteral stent and/or nephrostomy tube is required. An extrarenal drain can be placed to detect a urine leak. Copiously irrigate the surrounding tissue to reduce the risk of abscess. 

Coagulum pyelolithotomy

Coagulum pyelolithotomy is used when multiple small stones are present and are scattered throughout the calyceal system. Coagulum, or a clot, envelops the small stones, and fragments are removed with it.

Into the renal pelvis through a 19-gauge needle, inject cryoprecipitate and 1 mL of methylene blue and inject 1 mL of thrombin and calcium chloride. Do not overdistend the renal pelvis.

Block the ureter with a noncrushing bulldog clamp. Thrombin and calcium chloride solution can be made by adding 5000 U of thrombin to 5 mL of saline and adding 10 mL of 10% calcium chloride. Another method to make coagulum is to inject the necessary volume of cryoprecipitate (ie, volume equal to that of the renal pelvis) and inject 1 mL of 10% calcium chloride. After 5-7 minutes, the clot is formed. The thromboplastin from the renal pelvis is used. Pyelolithotomy is then performed, and the clot, along with the stones, is removed.

The procedure is usually safe, but pulmonary embolism and hepatitis are possibilities. This procedure is rarely performed in the United States because of concerns about possible infectious agents in the materials used.

Summary

Note the following key points:

• The kidney is always higher than estimated.

• Position is the key for easier surgery.

• Incise skin and muscles toward the xiphisternum.

• Identify the ureter.

• Mobilize the whole kidney (all around).

• Be prepared to extend the incision in the renal pelvis to the calyx (Gil-Vernet procedure).

• Extend the incision across the UPJ if needed to remove a larger stone, but close it transversely to prevent narrowing.

A plain x-ray film of the abdomen (KUB) is essential because kidney stones are notorious for moving. Kidney position is always higher than visualized on the x-ray film; always incise above the site noted. Always assume more than one stone is present in the renal pelvis. Make a bigger incision to gain better exposure. Be prepared to take intraoperative x-ray films.

Recognize the left testicular vein or ovarian vein on the left side and on the right side of the vena cava. Gonadal veins may be sacrificed if the need arises. Always mobilize the entire kidney, both upper and lower poles. Be prepared to extend the pyelotomy incision. The UPJ is not inviable; make sure it is not narrowed when closing.

If necessary, perform an extended pyelolithotomy to remove a larger stone. Always use stone forceps to remove the stones, not regular forceps. When in doubt, perform a nephroscopy or obtain an intraoperative x-ray film. When a caliceal stone is present, incise the calyx and the infundibulum and then remove the stone with the stone forceps. If several small stones are present, consider the use of a coagulum pyelolithotomy.

Pain is less severe if bupivacaine (Marcaine) is injected, but be absolutely sure that the bupivacaine is not accidentally injected into a vessel because it can cause cardiac arrhythmias.

Drains may be removed in 24 hours if the drainage is less than 25 mL. Ureteral stents can be removed after 2 weeks. If a ureteral catheter is used as a stent, it can be removed after 5 days.

Perform an imaging study to confirm the removal of all stone particles.

As with all renal stone procedures, a urinary tract infection or pyelonephritis may occur. Perinephric abscesses may require percutaneous drainage. Retained stone fragments, ureteral/renal pelvic scarring, and obstruction are possibilities that may require additional open or endoscopic urologic surgery.

As with any surgery, atelectasis is the most common complication of stone surgery. Aggressive incentive spirometry and patient ambulation assist in treating this complication. Some advocate a brief period of hyperventilation with vigorous lung expansion immediately postoperatively while the patient is supine and just prior to extubation.

Other complications include urine leak or urinoma, urinary fistula (to skin or bowel), bleeding, arteriovenous malformations, pseudoaneurysms, and injury to pleura/lung with pneumothorax. The vast majority of cases with urinary leakage and fistula between the collecting system and skin can be treated with a ureteral stent; percutaneous placement of a perinephric drain may be needed if an intraoperative drain was not placed or has already been removed at the time the leak is recognized. An indwelling urethral catheter may also be needed to divert the flow from the fistula tract and allow it to seal.

A small pneumothorax without respiratory distress due to an iatrogenic pleural injury can usually be treated conservatively and monitored. Larger air pockets can be treated with aspiration or a chest tube. If a lung injury is also present, a chest tube should be the initial therapy.

Fistula with the bowel can sometimes be managed with a stent, urethral indwelling catheter, bowel rest, and parenteral nutrition. If the fistula does not respond to this conservative management, surgical repair and possible nephrectomy and/or bowel resection may be necessary.

Bleeding, arteriovenous malformations, and pseudoaneurysms can be severe problems that may require embolization, emergent surgical intervention, transfusion, possible loss of the kidney, and even loss of life in extreme cases.

While the stone-free rates after pyelolithotomy are excellent for solitary renal pelvic stones, the morbidity is so much greater than even multiple percutaneous, ureteroscopic, and/or extracorporeal shockwave approaches that this procedure is rarely used. Urologists practicing before the advent of these technologies or in areas with little access to the complex instrumentation for noninvasive stone management have the most experience and best surgical results.

Note that patients should be informed about kidney stone prevention metabolic analysis, including a 24-hour urine collection for calcium, citrate, oxalate, magnesium, phosphate, sodium, uric acid, and total volume analysis. Optimally, a screening blood test for hypercalcemia, hyperparathyroidism, and hyperuricemia should also be performed. Testing protocols are available commercially from Dianon Systems (Stratford, Conn), UroCor Labs (Oklahoma City, Okla), LabCorp (Burlington, NC), and other laboratories.

Because of the advent of extracorporeal shockwave lithotripsy (ESWL) and percutaneous nephropyelolithotomy (PCN), pyelolithotomy is becoming an uncommon surgery in most developed countries. Pyelolithotomy is invasive, but it continues to have role in certain cases due to the size or shape of the stone, inaccessibility to ESWL and PCN, or the need for concomitant open surgical intervention for related problems.

Laparoscopic/robotic pyelolithotomy has growing support, especially when laparoscopic reconstruction of a UPJ obstruction is planned.[7, 8, 9, 6]