Pre-operative assessment:
- Planning with appropriate imaging – CT +/- contrast (stone, calyces, colon, hepatosplenomegaly)
- Consider split function renogram in large staghorns
- Urine culture, any infection treated or drained
- Planning access – urologist vs radiologist
- Planning supine vs prone, availability of equipment (2 stacks if ECIRS, laser, trays etc)
- Bloods inc coags and G+H
- Medical optimisation
- Appropriate consent, potential for multiple procedures
Contra-indications:
- Uncorrected coagulopathy
- Untreated urinary tract infection
- Tumour or malignancy in kidney
- Pregnancy (relative)
- Morbid obesity (relative)
- Inability to position prone or access kidney
Initial set-up
- Cystoscopy and placement of ureteric catheter
- Initial II shot prior to any contrast – save this
- Contrast mixed with methylene blue
- Maintain ureteric catheter access for puncture – additional tubing
Puncture
- Posterior calyx preferred – less bleeding (less parenchyma) and much more direct access to renal pelvis and collecting system
- Posterior (medial) to mid/posterior axillary line
- Aim to puncture calyx end on through papilla – avoiding interlobar arteries
- Interlobar arteries run alongside parallel to infundibulum – avoid trans-infundibular access
- Bullseye approach end on vs parallax/biplanar approach
- Lower pole preferred – safest
- Upper pole / supracostal – risk of pleural transgression and chest complications increases (but access to entire kidney better with upper pole access, shorter tract)
- Puncture during end expiration reduces chance of lung injury
- 18G diamond-tip / Chiba needle
- Wire through and through into bladder/externalise if supine
- If can’t get wire down ureter, need maximum wire length in renal pelvis
- Hydrophilic wire initially, may be replaced with super-stiff wire
Upper pole puncture:
- Risk of pneumothorax or hydrothorax up to 10 – 20 %
- Visceral injury more common
- Ensure puncture/dilation in end expiration
- Avoid supra-11 unless necessary
- Puncture as far medial/posterior as possible adjacent to paraspinal muscles
Dilation
- Generally one-step balloon dilation with Nephromax or similar over wire under II guidance
- May need fascial incising needle if scarred kidney (waisting of balloon)
- Don’t dilate infundibulum
- Ensure Amplatz sheath backloaded over balloon before dilation
- May need longer sheaths etc in obese patients
- Alternative is sequential dilators or metal telescopic dilators – probably more bleeding
- Secure sheath to ensure doesn’t migrate (can suture to skin)
Nephroscopy and stone clearance
- Rigid nephroscopy and flexible cystoscope
- Laser, lithoclast or ultrasound all useful
- May use combined retrograde access / ECIRS for stone positioning
Other considerations:
- Supine vs prone
- Surgeon preference
- Supine pros – allows ECIRS, do not have to reposition, avoids anaesthetic complications of prone, allows US guided access, ergonomic for surgeon, theoretically reduced risk of colon puncture, maximal drainage through sheath of fluid and fragments due to gravity
- Supine cons – does not allow upper pole puncture typically or multiple tracts, kidney is hypermobile cf. prone, potentially cramped operating space, longer tract length
- Mini PCNL
- Less bleeding, but probably longer procedure for larger stones
- No significant different in SFR
- Tubeless
- Can leave just stent or just nephrostomy or both
- Leaving nephrostomy has benefit of facilitating access for repeat procedure if incomplete stone clearance, but increased post-operative pain
Complications of PCNL – see dedicated page