Surgical Therapy of Nephrolithaisis

Question 1

What imaging should you get prior to performing a PCNL?

Answer 1

Guideline 1: Clinicians should obtain a non-contrast CT scan on patients prior to performing PCNL (it defines stone burden and distribution, and provides information regarding collecting system anatomy, position of peri-renal structures and relevant anatomic variants) low dose is ok

Question 2

What imaging may help you decide between SWL and URS?

Answer 2

Guideline 2: Clinicians may obtain a non-contrast CT scan to help select the best candidate for SWL versus URS (skin to stone distance < 11 cm and HU < 1000 for SWL)

Question 3

If you suspect a kidney has been compromised because of nephrolithiasis, what should you do?

Answer 3

Guideline 3: If a clinician suspects compromise of renal function, obtaining a functional imaging study (DTPA or MAG‐3) can help guide treatment for stone disease

Question 4

What tests should you order prior to surgery for nephrolithiasis?

Answer 4

Guideline statement 4: Clinicians are required to obtain a urinalysis prior to intervention. In patients with clinical or laboratory signs of infection, urine culture should be obtained (intra-op proximal urine and/or stone cx can also be obtained to help guide post-therapy abx)

Guideline 5: Clinicians should obtain a CBC and platelet count on patients undergoing procedures where there is a significant risk of hemorrhage or for patients with symptoms suggesting anemia, thrombocytopenia, or infection; serum electrolytes and creatinine should be obtained if there is suspicion of reduced renal function.

Question 5

What is the treatment of choice for uncomplicated ureteral stones ≤10 mm?

Answer 5

Guideline 7: those with uncomplicated ureteral stones ≤10 mm and distal stones of similar size should be offered MET with α-blockers.

(uncomplicated patients mean pain is well controlled and there are no signs of infection or high grade obstruction)

Patients should be aware that these meds are prescribed for an off label indication

Question 6

What should you do in a patient who fails MET with a ureteral stone prior to deciding on operation?

Answer 6

Statement 8: Clinicians should offer reimaging to patients prior to surgery if passage of ureteral stones is suspected or if stone movement will change management. Reimaging should focus on the region of interest and limit radiation exposure to uninvolved regions.

Question 7

How long should you offer MET/observation for in a patient with a ureteral stone < 10 mm?

Answer 7

Statement 9: In most patients, if observation with or without MET is not successful after four to six weeks and/or the patient/clinician decide to intervene sooner based on a shared decision making approach, the clinicians should offer definitive stone treatment.

Question 8

What should you inform patients about surgical options prior to choosing surgery for ureteral stones <10 mm?

Answer 8

statement 10: Clinicians should inform patients that SWL is the procedure with the least morbidity and lowest complication rate, but URS has a greater stone-free rate in a single procedure.

Question 9

In patients with mid or distal ureteral stones who require intervention (who were not candidates for or who failed MET), what surgery is preferred?

Answer 9

Guideline 11: Clinicians should recommend URS as first-line therapy. For patients who decline URS, clinicians should offer SWL

*Of note, stone-free rates with URS for proximal ureteral stones <10 mm were superior, those for such stones >10 mm were equivalent so this guideline recommendation does not include proximal ureteral stones

Question 10

In patients with suspected cystine or uric acid ureteral stones who fail MET or desire intervention, what surgery is preferred?

Answer 10

Guideline 12: URS is recommended

Question 11

What should you not routinely do in a patient with a ureteral stone undergoing SWL?

Answer 11

Guideline 13: Routine stenting should not be performed in patients undergoing SWL

Question 12

Following URS, when may clinicians omit ureteral stenting?

Answer 12

Guideline 14: Clinicians may omit ureteral stent in those without suspected ureteric injury during URS, those without evidence of ureteral stricture or other anatomical impediments to stone fragment clearance, those with a normal contralateral kidney, those without renal functional impairment, and those in whom a secondary URS procedure is not planned

Note: it doesn’t say anything about bilateral ureteroscopy….

Question 13

Prior to ureteroscopy surgery for nephrolithiasis, what should you not do routinely?

Answer 13

Guideline 15: Placement of a ureteral stent prior to URS should not be performed routinely.

While pre-stenting is shown to improve stone free rates, the cost and QoL factors related to a stent are not deemed worth it.

Question 14

What should you offer to patients to reduce ureteral stent discomfort?

Answer 14

Guideline 16: Clinicians may offer α-blockers and antimuscarinic therapy to reduce stent discomfort

Other options to reduce stent discomfort: bladder analgesics for dysuria, non-steroidal anti-inflammatory agents (NSAIDs), and narcotic analgesics

Question 15

What should you offer In patients with large or complex ureteral stone burdens, whom neither URS nor SWL are likely to accomplish stone clearance in a reasonable number of procedures?

Answer 15

Guideline 17: In patients who fail or are unlikely to have successful results with SWL and/or URS, clinicians may offer PCNL, laparoscopic, open, or robotic assisted stone removal.

(PCLN is preferred, but lap and robotic surgeries are preferred over open)

Question 16

If you are performing URS for a proximal ureteral stone, what scope should you use?

Answer 16

Guideline 18: Clinicians performing URS for proximal ureteral stones should have a flexible ureteroscope available.

Flexible URS has been shown in both prospective and retrospective studies to have high overall success rates with low morbidity/complications for < 2 cm proximal ureteral stones.

Question 17

What is first-line modality for intra-ureteral lithotripsy?

Answer 17

Guideline 19: Clinicians should not utilize EHL as the first-line modality for intra-ureteral lithotripsy

Your options are pneumatic or laser lithotripsy

*Electrohydraulic lithotripsy (EHL) may be used safely in the renal pelvis

Question 18

What should you do in a patient with an obstructing stone and suspected infection?

Answer 18

Guideline 20: In patients with obstructing stones and suspected infection, clinicians must urgently drain the collecting system with a stent or nephrostomy tube and delay stone treatment.

Question 19

In a symptomatic patient with a non-lower pole renal stone burden of < 20 mm, what should you offer?

Answer 19

Guideline 21: In symptomatic patients with a total non-lower pole renal stone burden < 20 mm, clinicians may offer SWL or URS

Question 20

What surgery should you offer for adult symptomatic patients with a total renal stone burden >20 mm?

Answer 20

Guideline 22: In symptomatic patients with a total renal stone burden >20 mm, clinicians should offer PCNL as first-line therapy.

Guideline 23: In adult patients with total renal stone burden >20 mm, clinicians should not offer SWL as first-line therapy

Question 21

What may you do in a patient who requires treatment in a kidney that has negligible function?

Answer 21

Guideline 27: Clinicians may perform nephrectomy when the involved kidney has negligible function in patients requiring treatment

Remember, observation may be appropriate for some asymptomatic patients. However, poorly functioning kidneys can often be a source of persistent infection, pain, and pyelonephritis.

Question 22

What should you do for a symptomatic patient with non-obstructing caliceal stones and no other etiology for pain?

Answer 22

Guideline 28: For patients with symptomatic (flank pain), non-obstructing, caliceal stones without another obvious etiology for pain, clinicians may offer stone treatment. (but the patient must be aware their pain might not improve)

• Treatment should also be considered in cases of associated infection, vocational reasons (e.g. airline pilots, military), and poor access to contemporary medical care

Guideline 29: For patients with asymptomatic, non-obstructing caliceal stones, clinicians may offer active surveillance

Question 23

What should you offer to patients with symptomatic ≤ 10 mm lower pole renal stones?

Answer 23

Guideline 30: Clinicians should offer SWL or URS to patients with symptomatic ≤ 10 mm lower pole renal stones.

Guideline 31: Clinicians should not offer SWL as first-line therapy to patients with >10mm lower pole stones.

* Certain techniques employed during URS, including repositioning of stones into the upper pole before fragmentation, utilization of a ureteral access sheath, and extraction of the generated fragments, may improve results

Question 24

What should you tell patients with symptomatic lower pole stones > 10 mm in size about their surgery options?

Answer 24

Guideline 32: Clinicians should inform patients with lower pole stones >10 mm in size that PCNL has a higher stone-free rate but greater morbidity

Question 25

Should you place a nephrostomy tube in an uncomplicated PCNL who are presumed stone-free?

Answer 25

Guideline 33: In patients undergoing uncomplicated PCNL who are presumed stone-free, placement of a nephrostomy tube is optional

The tubeless approach should not be undertaken if there is active hemorrhage or it is likely that another PCNL will be needed to remove residual stones.

Question 26

What is a surgical step that should be a routine part of standard PCNL?

Answer 26

Guideline 34: Flexible nephroscopy should be a routine part of standard PCNL

Question 27

What kind of irrigation should you use in PCNL and URS?

Answer 27

Guideline 35: Clinicians must use normal saline irrigation for PCNL and URS

Question 28

What should you do for patient who are not considered candidates for PCNL?

Answer 28

Guideline 39: offer staged URS

relative contraindications to PCNL include use of anti-coagulation or anti-platelet therapy that cannot be discontinued or the presence of contractures, flexion deformities, or other anatomic derangements that may preclude positioning for PCNL

Question 29

What may you prescribe after SWL to facilitate passage of stone fragments?

Answer 29

Guideline 40: Clinicians may prescribe α-blockers to facilitate passage of stone fragments following SWL

Question 30

What is an absolute contraindication to SWL?

Answer 30

Guideline 43: SWL should not be used in the patient with anatomic or functional obstruction of the collecting system or ureter distal to the stone.

Should not be offered to pregnant women as well.

Question 31

What therapy should be preferentially utilized in patients with symptomatic caliceal diverticular stones?

Answer 31

Guideline 44: In patients with symptomatic caliceal diverticular stones, endoscopic therapy (URS, PCNL, laparoscopic, robotic) should be preferentially utilized

The choice of optimal endoscopic approach should be based on stone location and size, relation to surrounding structures, and patient preference.

Question 32

What should you do with staghorn stones?

Answer 32

Guideline 45: Staghorn stones should be removed if attendant comorbidities do not preclude treatment

Question 33

For pediatric patients with a total renal stone burden >20mm, what treatment is acceptable?

Answer 33

Guideline 51: In pediatric patients with a total renal stone burden >20mm, both PCNL and SWL are acceptable treatment options

Question 34

Who would you remember to include when dealing with a pregnant women with a stone?

Answer 34

Guideline 54: In pregnant patients, clinicians should coordinate pharmacological and surgical intervention with the obstetrician

Question 35

What should you offer pregnant people who fail observation?

Answer 35

Guideline 56: In pregnant patients with ureteral stones, clinicians may offer URS to patients who fail observation. Ureteral stent and nephrostomy tube are alternative options with frequent stent or tube changes usually being necessary

Question 36

What are some stone surgery truths (accountable to all patients, all stones, all sizes)?

Answer 36

Guideline 23: When residual fragments are present, clinicians should offer patients endoscopic procedures to render the patients stone-free, especially if infection stones are suspected

Guideline 24: Stone material should be sent for analysis.

Guideline 26: Open/laparoscopic/robotic surgery should not be offered as first-line therapy to most patients with stones.

Guideline 36: A safety guide wire should be used for most endoscopic procedures.

Question 37

What antimicrobial prophylaxis should be administered prior to stone intervention?

Answer 37

Guideline 37: Antimicrobial prophylaxis should be administered prior to stone intervention and is based primarily on prior urine culture results, the local antibiogram, and in consultation with the current Best Practice Policy Statements on Antibiotic Prophylaxis

Question 38

What should you do if you encounter purulent urine during an endoscopic intervention?

Answer 38

Guideline 38: Clinicians should abort stone removal procedures, establish appropriate drainage, continue antibiotic therapy, and obtain a urine culture if purulent urine is encountered during endoscopic intervention

Question 39

If initial SWL fails, should you try it again?

Answer 39

Guideline 41: If initial SWL fails, clinicians should offer endoscopic therapy as the next treatment option.

Question 40

what is your first-line treatment therapy in a patient with uncorrected bleeding diatheses or who require continuous anticoagulation/antiplatelet therapy?

Answer 40

Guideline 42: Clinicians should use URS as first-line therapy in most patients who require stone intervention in the setting of uncorrected bleeding diatheses or who require continuous anticoagulation/antiplatelet therapy

All patients, all size stones, all locations.

Question 41

According to 2019 AUA antimicrobial best practice guidelines, what antibiotics, if any, should you give before SWL?

Answer 41

Antibiotics are only needed if patient risk factors (old age, recent infection, immunocomprised state, poor nutrition, etc).

Antibiotics of choice for these people are bactrim OR 1st or 2nd generation cephalosporin OR Aminopenicillin combined with a β- lactamase inhibitor and Metronidazole

Should be single dose only

Question 42

According to 2019 AUA antimicrobial best practice guidelines, what antibiotics, if any, should you give before URS?

Answer 42

All persons require antibiotics.

Antibiotics of choice are bactrim or 1st or 2nd generation cephalosporin

Second choice abx: aminoglycoside +/- ampicillin, Aztreonam +/- Ampicillin or amoxicillin/clavulanate

Should be single dose only

Question 43

According to 2019 AUA antimicrobial best practice guidelines, what antibiotics, if any, should you give before PCNL?

Answer 43

All persons require antibiotics.

Antibiotics of choice are: 1st or 2nd generation cephalosporin OR aminoglycoside + metronidazole or clindamycin

Second choice abx: ampicillin/sulbactam (Unasyn) or fluoroquinolone

Question 44

Intraoperative PCNL complications and mgmt?

Answer 44

Venous bleeding: abort, inflate foley in renal pelvis to tamponade

Arterial bleeding: abort, arteriogram and embolize

Stone migrated out of pelvis: abort, leave stone

Significant tear in pelvis: abort

Irrigation mismatch: abort if irrigant loss > 1000 mL

Post OP: non-con CT (evaluate residual calculus, post-op hematoma, PTX, fluid accumulation)

Antegrade nephrostogram