Percutaneous Access

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Percutaneous Nephrostolithotomy Access and Tools


Michael Parks, CST, AAS
Indiana University Health Methodist
Hospital Indianapolis, IN






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Percutaneous Stone Removal

• In whom?
• How to do it?
• Before
• During
• After

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Lingemans Law for the Management of Renal
Lithiasis

• If the stone problem is simple, do SWL if the
  problem isnt simple, do PNL.

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Simple

• Stone burden lt2 cm
• Normal renal anatomy

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Complex

• Stone burden gt2cm
• Staghorn stones
• Abnormal renal anatomy
• UPJ obstruction
• Horseshoe kidney
• Calyceal diverticulum
• Lower pole gt1cm
• Cystine, brushite, COM

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Advances in PCNL Technique

• Access by the urologist
• Glide wires for access
• Tract dilatation balloons
• Improved intracorporeal lithotripsy
  (pneumatic devices, holmium laser)
• Flexible nephroscopy
• Small nephrostomy tubes

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Access General Principles

• Single stage procedure best done in OR
• Placement of ureteral catheter
• C-arm fluoroscopy
• Precise calyceal puncture
• Safety wire as far into the urinary tract as
  possible
• Amplatz sheath - always

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Operating Room Set-up
Separate imaging table with C-arm preferred to
urotables with fixed x-ray tubes
Under table x-ray source (reduces operator
exposure)
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Selection of Renal Access Site

• Most important factors
• Stone location and burden
• Site selected to maximize stone removal via rigid
  nephroscope
• Lower pole access generally preferred secondary
  to lower morbidity

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Anesthesia Requirements

• General anesthesia preferred
• Best airway protection when prone
• Allows suspension of respiratory excursions (hold
  at end expiration)
• Local anesthesia is an option
• Adjunctive intravenous sedation

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Ureteral Catheter

• Patient placed in dorsal lithotomy position
  initially
• Ureteral catheter placed cystoscopically on side
  of stone
• 5F open-ended catheter
• 7F ureteral occlusion balloon catheter

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Ureteral Catheter
Ureteral balloon occlusion catheter (large stones
or dilated ureter)
Balloon prevents stone fragments from entering UPJ
Balloon seated at UPJ Use 1.5cc contrast
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Patient Positioning

• Patient placed in prone position (flank inferior
  to center post)
• Arm on stone side rested on arm board (flexed
  90) opposite arm against patient
• Pressure points padded

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Patient Positioning

• Foam wedge placed under patient for 30 elevation
• Brings posterior calyces into vertical orientation

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Accurate Calyceal Access
Posterolateral access into a posterior calyx goes
through Brödel's line
Anterior calyx can be punctured but guide wire
manipulation more difficult
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Accurate Calyceal Access

• Puncture site medial to posterior axillary line
  (avoids colon)
• Precise mid-calyx puncture required
• Avoids peri-infundibular venous plexus

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Imaging Modalities for Access in OR

• Fluoroscopic
• Offers best delineation of calyceal anatomy
• Use 18-gauge diamond-tipped needle

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Imaging Modalities Triangulation Technique

• C-arm angled away from pole of access
• Localize calyx of puncture in two planes
• AP to needle
• Oblique to needle

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Imaging Modalities Triangulation Technique

• AP plane (left - right adjustments)

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Imaging Modalities Triangulation Technique

• AP plane (left - right adjustments)

Too lateral
Too medial
Correct alignment
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Imaging Modalities Triangulation Technique

• Oblique plane (up - down adjustments)

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Imaging Modalities Triangulation Technique

• Oblique plane (up - down adjustments)

Correct alignment
Too caudad
Too cephalad
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Confirming Access

• Aspiration
• Attach IV tubing and 20 cc syringe to access
  needle
• Drawback on syringe
• If no return, slowly withdraw tip of needle under
  fluoroscopic guidance

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Guide Wires

• Place as much wire into the urinary tract as
  feasible
• Ureteral placement is optimal
• If unable to negotiate into ureter then coil wire
  into peripheral portion of collecting system

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Guide Wires

• Types of guide wires utilized
• Hydrophilic (glide) wire
• Teflon-coated moveable core wires
• Straight 0.035"
• J-tipped 0.035"
• Amplatz superstiff wire

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Guide Wires
Manipulation of glidewire into ureter

• Utilize angiographic catheter (5F Cobra most
  common)
• Dilate over glidewire with 8F fascial dilator
  initially
• Inject angiographic catheter with saline and run
  moist 4 x 4 over glidewire to ensure easy passage
  of catheter

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Guide Wires

• Placement of safety wire
• Once glidewire down ureter, feed angiographic
  catheter over wire
• Exchange glidewire with Amplatz superstiff wire
• Insert 8/10 coaxial catheter set
• Secure safety wire (0.035" straight)

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Tract Dilation

• Always monitor dilation process under fluoroscopy
• Methods
• Amplatz sequential dilators
• Metal telescopic dilators
• Balloon dilation catheter

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Tract Dilation
Amplatz sequential dilators (12 to 30F)

• Inserted sequentially over 8F portion of coaxial
  set
• 34F sheath inserted over final dilator
• Dilation process can be cumbersome

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Tract Dilation
Metal telescopic dilator set

• Initial placement of hollow rod over 0.035" guide
  wire
• Sequential dilation up to 30F
• Useful in cases of previous scar
• Must control distal movement of rod to prevent
  injury

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Tract Dilation

• 7F Balloon dilation catheter (Nephromax)
• Inflate to 13 atm of pressure, 34F sheath placed
• Radial dilation in a single step
• Incomplete dilation possible if scar is present
  (seen by waist)

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Power Lithotripsy

• Rigid

Flexible
Electrohydraulic
Ultrasound
Laser
Lithoclast (pneumatic) Lithoclast/Ultrasound(Ultra
)
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Swiss LithoClast Ultra Console
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Rigid Nephroscopes

• New instruments are longer and have improved
  optics
• Maximize use of rigid scopes and ultrasonic
  lithotripter

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Flexible Nephroscopes

• Same instrument as flexible cystoscope
• Digital instruments now available
• Use on every percutaneous procedure
• best if Amplatz sheath used for access

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Flexible Nephroscopes Set Up

• Amplatz sheath
• Pressurize irrigant to 300 mmHg
• Contrast plus fluoroscopy to assist in
  orientation, documentation

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Flexible Nephroscopes
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Irrigation Set Up
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Flexible Nephroscopy
Nitinol Tipless Stone Extractor

• Can easily access stone fragments in peripheral
  calices
• Nitinol material atraumatic to urothelium

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Conclusions

• Improved efficiency and efficacy of PNL
• Refinements in percutaneous access techniques
• Advances in equipment (guide wires, balloon
  dilation catheter, Nitinol basket)
• Access by the urologist