URETERAL STONES: A Brief Review of Diagnosis and Treatment

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URETERAL STONES A Brief Review of Diagnosis
and Treatment
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EPIDEMIOLOGY

• 12 risk in lifetime
• 2-3 risk of renal colic
• Recurs within 2-3 years
• Occurs in men three times more than woman
• Peak incidence from 30 to 50
• Factors that may increase incidence diet,
  lifestyle, social status, heredity, geography

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TYPES OF STONES

• 75 calcium oxalate or phosphate
• 15 phosphate-containing, most commonly struvite
  (magnesium ammonium phosphate)
• 5-10 uric acid
• 1 cystine
• Rarely, pure matrix and indinavir deposition

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LOCATIONS OF STONES

• Ureteropelvic junction (UPJ)
• Pelvic brim (at the bifurcation of the iliac
  vessels where the ureter courses anterior and
  medial to the vessels and is compressed)
• Ureterovesical junction (UVJ)

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URETERAL CALCULI
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L1/L2 Junction
Tips of transverse processes
Stone
Sacroiliac joint
Curves medially, Lateral to curve of sacrum
Enters bladder near sacro-coccygeal
junction. Level with Ischial spines
Phlebolith
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SIGNS AND SYMPTOMS

• Severe, intermittent unilateral flank that
  radiates to the groin causing the patient to
  writhe around at its height of intensity
• Microscopic hematuria
• If febrile, then may be a complicated ureteral
  obstruction by either infection with obstruction
  or acute pyelonephritis

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DIFFERENTIAL DIAGNOSIS

• Genitourinary causes pyelonephritis, torsion of
  a pelvic mass
• Gastrointestinal causes appendicitis,
  diverticulitis, cholecystitis, choledocholithiasis
  , pancreatitis, bowel obstruction, Crohns
  disease, torsion of an abdominal mass
• Vascular causes aortic dissection, ruptured
  abdominal aortic aneurysm

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PLAIN RADIOGRAPHY

• Relies solely on the identification of a calcific
  density along the expected ureteral tract
• Only 59 of ureteral calculi are visible
• Cystine stones are mildly radiodense
• Uric acid, pure matrix, and indinavir stones are
  radiolucent

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ULTRASOUND

• Not recommended
• Detects indirect signs of obstruction collecting
  system dilatation, a change in renal blood flow,
  a loss of a ureteric jet
• Rarely identifies urolithiasis except at the UPJ
  or UVJ
• Difficulty in measuring the size of a stone

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INTRAVENOUS PYELOGRAM (IVP)

• Advantages availability, low cost, ability to
  assess renal function
• Disadvantages requires intravenous contrast,
  prolonged exam time, inability to assess other
  causes of the clinical presentation, difficulty
  in distinguishing calcific densities
• Sensitivity 87 and specificity 94

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IVP Radiographic Findings of Ureteral Stone
Obstruction

• Opacity along the urinary tract
• Dilatation of ureter down to obstruction
• Dilatation of collecting system
• Delay in contrast of nephrogram
• Delay in contrast of collecting system
• Delay in contrast excretion

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IVP Radiographic Findings of Ureteral Stone
Obstruction
Figure1. a. An opacity is visible within the
pelvis on the right side. b. The right ureter is
full of contrast down to the site of obstruction.
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NONCONTRAST HELICAL CT (NCCT)

• Imaging modality of choice
• Advantages speed, safety, ability to assess
  other causes of the clinical presentation, and in
  some places, equivalent cost to IVP
• Disadvantages Inability to assess renal
  function, difficulty in assessing patients that
  have insufficient renal fat, difficulty in
  distinguishing calcific densities
• Sensitivity 95 and specificity 95

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NCCT Direct Stone Visualization

• Hallmark finding is a stone in the lumen of the
  ureter on the side of renal colic
• Virtually all stones are seen on CT except pure
  matrix and indinivar stones

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NCCT Secondary Signs of Ureteral Obstruction

• Ureteral dilatation
• Collecting system dilatation
• Perinephric stranding
• Periureteric stranding
• Nephromegaly
• Rim sign
• Absence of the white pyramids

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MAGNETIC RESONANCE UROGRAPHY (MRU)

• Identifies stones and some secondary signs of
  obstruction
• Advantages no radiation and contrast
• Disadvantages inability to image unobstructed
  urinary tract, expensive, slow

Figure 7. MRU show obstruction of the right
ureter.
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URETERAL CALCULI
TREATMENT CONSIDERATIONS

• Location
• Size
• Chronicity
• Equipment
• Expertise

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URETERAL CALCULI
TREATMENT OPTIONS

• Observation
• Shock wave lithotripsy
• Ureteroscopy
• Blind basket extraction
• Percutaneous approach
• Open surgery

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CONSERVATIVE MANAGEMENT

• Analgesics, hydration, and possibly
  antispasmodics
• Follow plain radiographs at 1-2 week intervals

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URETERAL CALCULI
SPONTANEOUS PASSAGE
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URETERAL CALCULI
SPONTANEOUS PASSAGE

• Of all stonesthat pass spontaneously, 95 will
  pass within 6 weeks

Miller Kane, 1999
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URETERAL CALCULI
MEDICAL MANAGEMENT
Hollingsworth Hollenbeck, 2006
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URETERAL CALCULI
MEDICAL MANAGEMENT
Hollingsworth Hollenbeck, 2006
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INTERVENTIONAL MANAGEMENT Current Therapy

• Extracorporeal shock wave lithotripsy (for
  proximal ureteral stones and least invasive
  therapy)
• Ureteroscopy (for mid and distal ureteral stones)

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URETERAL CALCULI
PARAMETERS FOR COMPARISON

• Stone-free is not everything !!

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URETERAL CALCULI
PARAMETERS FOR COMPARISON

• Effectiveness
• Morbidity
• Convalescence
• Cost

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DISTAL URETERAL CALCULI
COMPARISON OFMONOTHERAPY STUDIES

• URS is 10 - 18 more effective than SWL
  (depending on type of SWL unit)
• Morbidity / convalescence reduced with SWL
• Need for stents 40-60 less with SWL
• Cost issues not addressed in monotherapy studies

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DISTAL URETERAL CALCULI
OVERVIEW OF HISTORICALCONTROL STUDIES

• SWL URS
• Effectiveness Slightly better
• Morbidity Less
• Hospitalization Less
• Cost Slightly less

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DISTAL URETERAL CALCULI
PROSPECTIVE, RANDOMIZED TRIAL

• 80 patients randomized to receive SWL or URS 40
  patients had stones gt 5 mm 40 patients had
  stones lt 5 mm
• SWL performed on Dornier MFL 5000
• URS performed with 6.5F or 9.5F semi-rigid
  ureteroscopes (basket vs. pneumatic lithotripsy)

Peschel Bartsch, 1999
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DISTAL URETERAL CALCULI
PROSPECTIVE, RANDOMIZED TRIALSTONES lt 5 MM

• URS SWL
• OR time (min) 19 63
• Fluoro time (min) 0.8 5.1
• Stone-free (days) 0.2 10.8
• Stent (days) 7.2 0
• Re-treatment rate 0 15

Peschel Bartsch, 1999
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URETEROSCOPY
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Ureteroscopy

• Easier for lower stones
• Extraction of stone fragments
• Fragmentation
• Laser Homium Yg
• Mechanical EKL
• Explosive EHL
• Ultrasound
• Risks

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URETERAL CALCULI
FLEXIBLE URETEROSCOPY
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URETERAL STONE MANAGEMENT
URETEROSCOPY

• AdvantagesHighest success rateDefinitive Rx -
  No waiting for stone passage
• DisadvantagesMore invasive than SWLHigher
  complication rateRequires greater technical
  expertise

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Rigid ureteroscope specifications include the
following

• Tip diameter - 4.5-9.5F (6.9F most common)
• Optics - Fiberoptic bundles
• Working channels - One, 2, or 3 (2 channels
  preferred)
• Accessory length - Average, 40 cm

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Flexible ureteroscope specifications include the
following

• Tip diameter - 6.9-9.8F (7.5F most common)
• Optics - Fiberoptic bundles
• Working channel - Single, 3.6F
• Access - Guidewire (0.035 in nitinol or 0.038 in
  stainless steel)
• Accessory length - Average, 100 cm

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INTERVENTIONAL MANAGEMENT More Invasive
Treatments

• Intracorporeal shock wave lithotripsy (through
  ureteroscope)
• Percutaneous nephrostomy (for stones gt2 cm and in
  proximal collecting system)
• Laparoscopy (if complicated)
• Open surgery (rarely done)

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• Thank you