CUA Guideline: Management of ureteral calculi 2015 Flashcards
what percentage of stones 2-4 mm will pass spontaneously?
95%
What % of stones greater than 5mm will pass sponatneously?
50%
how do you measure stone size to determine passage?
width of stone on axial imaging
Stones up to 5mm distal ureter passage?
90% will in 40 days and can be managed conservatively.
stones larger than 5mm passage
less likely to pass and patient should be counselled about options
Who is a candidate for Medical Expulsive therapy?
patients with distal stones<10mm in size can be considered for alpha antagonists,
shortens duration and increases likelihood of stone passage
What are recommendations regarding URS and ESLW for ureteral stones
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
Factors that affect SWL treatment success
Location in the ureter, Composition, Density of stone, skin to stone distance on CT.
What stone composition are more resistant to SWL?
Cystine, CaOxMH, brushite
at what threshold density do stones become less responsive to SWL?
900 to 1000 HU depending on the reference.
What is the threshold for SSD for SWL for success?
10 cm
SWL should ensure proper coupling to reduce air bubles blast path and prevent decoupling
TRUE
SWL targeting(fluoro or US) should occur at regular intervals throughout the treatment. Compression belts may help reduce renal and ureteric movement with tx.
TRUE
Why should SWL energy be increase gradually particulary for upper ureteric stones?
patient toleration
low dose shock induce vasoconstriction of kidney which is protective against hematomas
What should you do if first SWL was unsuccessful?
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
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
TRUE
should alpha blockers be offered to patients on SWL?
yes, tamsulosin, to improve treatment success rate
Do stents improve SFR in SWL?
NO, if anything they impede stone passage and cause lower SFRs.
Do stents decrease the risk of Steinstrausse or infection following SWL?
No
Is the use of ureteral access sheath recommended?
further studies are needed as per CUA
Is there any benefit to using smaller ureteroscopes?
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
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?
No,( hosking, densted studies) No, Yes Yes, stent one side Yes, place a sent, if not higher ER visits
Does prestenting patients for URS help?
Yes, in stones larger than 1cm better SFR.
Does stenting post URS help?
In select situations but does not change SFR, strictures but might decrease post op narcotic use and reduce ER visits
What MR sequence is better than imaging ureteral stones?
MRU with this sequence: Half fourier single-shot spin echo(HASTE)
Can URS be done on anticoagulation?
Yes, When the risks of withholding anticoagulants outweigh the benefits, proceeding with URS and laser lithotripsy which on AC is an acceptable option.
What are the most common type of stones in patients with diversions?
Magnesium ammonium phosphate(struvite) and calcium phosphate.
What is the most effective modality for clearing large obstructive ureteral stones in patients with diversion?
Percutaneous access and anterograde URS
When is anterograde URS indicated?
1) in select large proximal Ureteral stones
2) in conjunction with PCNL
3) following failure of retrograde URS
4) ureteral stone in transplant kidney
What is the typical HU of uric acid stones?
<500 HU
Is there a difference bw nephrostomy tube and stent for management of infected obstructed ureteral stone?
No, in one RCT there was no difference in time to defervesense, hospital stay, resolution of obstruction and overall clinical improvement.
