CUA Guideline: Management of ureteral calculi 2015

Question 1

what percentage of stones 2-4 mm will pass spontaneously?

Answer 1

95%

Question 2

What % of stones greater than 5mm will pass sponatneously?

Answer 2

50%

Question 3

how do you measure stone size to determine passage?

Answer 3

width of stone on axial imaging

Question 4

Stones up to 5mm distal ureter passage?

Answer 4

90% will in 40 days and can be managed conservatively.

Question 5

stones larger than 5mm passage

Answer 5

less likely to pass and patient should be counselled about options

Question 6

Who is a candidate for Medical Expulsive therapy?

Answer 6

patients with distal stones<10mm in size can be considered for alpha antagonists,
shortens duration and increases likelihood of stone passage

Question 7

What are recommendations regarding URS and ESLW for ureteral stones

Answer 7

Both SWL and URs safe. URS has higher liklihood of SFR esp for distal ureter, greater risk of comp, ESWL lower risk of comp but probably higher retreatment

Question 8

Factors that affect SWL treatment success

Answer 8

Location in the ureter, Composition, Density of stone, skin to stone distance on CT.

Question 9

What stone composition are more resistant to SWL?

Answer 9

Cystine, CaOxMH, brushite

Question 10

at what threshold density do stones become less responsive to SWL?

Answer 10

900 to 1000 HU depending on the reference.

Question 11

What is the threshold for SSD for SWL for success?

Answer 11

10 cm

Question 12

SWL should ensure proper coupling to reduce air bubles blast path and prevent decoupling

Answer 12

TRUE

Question 13

SWL targeting(fluoro or US) should occur at regular intervals throughout the treatment. Compression belts may help reduce renal and ureteric movement with tx.

Answer 13

TRUE

Question 14

Why should SWL energy be increase gradually particulary for upper ureteric stones?

Answer 14

patient toleration

low dose shock induce vasoconstriction of kidney which is protective against hematomas

Question 15

What should you do if first SWL was unsuccessful?

Answer 15

Can treat stone for a 2nd time with SWL, but more than two SWL treatments to same ureteric stone have little benefit and URS should be considered

Question 16

Patients with upper ureteric stones > 1cm or stones that have failed prior treatment should be treated wtih SWL with rate less than 120 shocks/min

Answer 16

TRUE

Question 17

should alpha blockers be offered to patients on SWL?

Answer 17

yes, tamsulosin, to improve treatment success rate

Question 18

Do stents improve SFR in SWL?

Answer 18

NO, if anything they impede stone passage and cause lower SFRs.

Question 19

Do stents decrease the risk of Steinstrausse or infection following SWL?

Answer 19

No

Question 20

Is the use of ureteral access sheath recommended?

Answer 20

further studies are needed as per CUA

Question 21

Is there any benefit to using smaller ureteroscopes?

Answer 21

Within the range of commercially available
semi-rigid and flexible ureteroscopes, the available
evidence suggests SFR and complication rates
are similar. When available, use of smaller ureteroscopes
may lessen the need for ureteral dilation and slightly reduce
minor postoperative complications such as hematuria

Question 22

Is stenting indicated post uncomplicated semirigid ureteroscopy? 
what if baloon dialate UO to 18F?
what if pneumatic lithotripter? 
bilateral ureteroscopy?
What if you use a UAS?

Answer 22

No,( hosking, densted studies) 
No, 
Yes
Yes, stent one side
Yes, place a sent, if not higher ER visits

Question 23

Does prestenting patients for URS help?

Answer 23

Yes, in stones larger than 1cm better SFR.

Question 24

Does stenting post URS help?

Answer 24

In select situations but does not change SFR, strictures but might decrease post op narcotic use and reduce ER visits

Question 25

What MR sequence is better than imaging ureteral stones?

Answer 25

MRU with this sequence: Half fourier single-shot spin echo(HASTE)

Question 26

Can URS be done on anticoagulation?

Answer 26

Yes, When the risks of withholding anticoagulants outweigh the benefits, proceeding with URS and laser lithotripsy which on AC is an acceptable option.

Question 27

What are the most common type of stones in patients with diversions?

Answer 27

Magnesium ammonium phosphate(struvite) and calcium phosphate.

Question 28

What is the most effective modality for clearing large obstructive ureteral stones in patients with diversion?

Answer 28

Percutaneous access and anterograde URS

Question 29

When is anterograde URS indicated?

Answer 29

1) in select large proximal Ureteral stones
2) in conjunction with PCNL
3) following failure of retrograde URS
4) ureteral stone in transplant kidney

Question 30

What is the typical HU of uric acid stones?

Answer 30

<500 HU

Question 31

Is there a difference bw nephrostomy tube and stent for management of infected obstructed ureteral stone?

Answer 31

No, in one RCT there was no difference in time to defervesense, hospital stay, resolution of obstruction and overall clinical improvement.