Potpourri
True or false: in a meta-analysis of randomized clinical trials comparing NSAIDs with opioids for the management of acute renal colic, NSAIDs were associated with a greater reduction in pain scores than opioids
True
The commonly used NSAID in the setting of acute renal colic is ketorolac. This is contraindicated in patients with renal failure or those with a history of gastrointestinal bleeding, hypersensitivity to aspirin or other NSAIDs, or in nursing or pregnant women
Skin to stone distance greater than ___ is associated with SWL failure?
SSD > 9-10 cm is associated with SWL failure
SSD: the average of measurements from the skin to the stone at 0, 45 and 90 degrees
Where should you get percutaneous access for a PCNL
Should be performed directly through a posterior calyx/papillae in an attempt to pass through the plane of Brodel (the division in anterior and posterior branches of the renal artery) and limit potential bleeding
Semirigid ureteroscopy is generally used to treat ureteral stones below what level?
Iliac vessels
What is the time frame for a stone trial of passage?
4-6 weeks
What is the ideal stone candidate for SWL? (size, location)
<10mm, upper pole
List the indications for PCNL
large (≥ 2 cm) and complex stones, staghorn calculi, lower pole renal stones > 1 cm, or stones in complex renal anatomy.
Stent placement is optional, but should be used when?
Ureteral edema, suspicion of ureteral injury, ureteral stricture, other anatomical impediments to stone fragment clearance, a solitary kidney, impaired renal function, or if a secondary URS procedure is planned
What does Ho:YAG stand for?
Holmium:yttrium-aluminum-garnet
Full points for either: What does steinstrasse mean in German? What is the rate of steinstrasse in patients undergoing SWL?
Stone street / street of stone
Up to 10%
Patients with positive urine cultures pre-operatively should be treated for how long before surgery?
≥ 1 week of culture-specific antibiotics before surgery
What is the rate of ureteral stricture following URS, and when should imaging be performed after surgery?
Ureteral stricture occurs in 0.5-4% of cases. Risk factors include a stone impacted for ≥ 2 months and/or ureteral injury.
Because obstruction due to stricture can occur silently, post-operative imaging with renal ultrasound (and KUB if the stone was fragmented) is recommended after any ureteroscopic procedure approximately 4-6 weeks post op
For mid to proximal ureteral stones the patient should be counselled that ___ is the procedure with the highest stone free rate, but ___ is associated with fewer complications
1. URS
2. SWL
What is the major disadvantage of an electromagnetic lithotriptor?
Small area of highly focused intrarenal energy results in increased subcapsular hematoma risk.
If the patient lacks peritoneal signs, how do you treat a bowel injury from PCNL?
The injury can be managed by withdrawing the nephrostomy tube into the bowel lumen and placing an internal ureteral stent to separately drain the colon and kidney
What do you do if you perforate the ureter?
Terminate procedure. Leave a stent in for 2-6 weeks
What are the sheath sizes for a standard PCNL vs mini vs ultramini?
24-30Fr, 14-22Fr, 11-13Fr
Which generator type is the most effective at breaking up stones, and what shape is the shockwave?
Electrohydraulic; spherical
How do you manage hemorrhage in the intraoperative vs postoperative period?
Most bleeding is venous and readily controlled with placement of a nephrostomy tube and allowing clot to form within the collecting system. If bleeding persists through and/or around the nephrostomy tube, place a tamponade balloon catheter to apply pressure along the nephrostomy track and can be used to tamponade bleeding for 48 hours. Postoperative hemorrhage that continues more than a few days after surgery or that recurs in a delayed setting is generally due to pseudoaneurysm, arteriovenous fistula, or segmental renal artery injury --> pursue arteriography and superselective embolization
What do you do if a stone is extruded?
Complete extrusion through ureteral perforation: do not try to retrieve
Partially extruded: try to remove the stone in order to prevent formation of a stone granuloma and stricture.
As long as a guidewire is in place, a ureteral stent can be placed and the procedure terminated.
If a stent cannot be placed then a NT should be inserted.