1. PCNL A Global Perspective
Dr CW Wong
Division of Urology
Department of Surgery
Pamela Youde Nethersole Eastern Hospital

2. Introduction and history
PCNL: what is it?
Indications
Imaging modalities for percutaneous access
Dilatation of the nephrostomy tract
Mini-perc technique
Mode of stone fragmentation
Chinese MPCNL: PYNEH experience
Conclusion

3. Introduction and history
1865 Thomas Hillier described first percutaneous nephrostomy
1955 Willard Goodwin & associates reported their experience with percutaneous nephrostomies in 16 patients
1976 Fernstrom & Johansson described a procedure through which a renal pelvic calculus could be extracted through a percutaneous tract
Early 80s Percutaneous nephrolithotomy gained widespread popularity

4. PCNL & ESWL
With the advent of ESWL in the mid 80s, the indications for percutaneous stone extraction were narrowed
As the limitations of ESWL were recognised, percutaneous surgery once again rose in popularity with a redefined role in stone management

5. PCNL: what is it? Percutaneous nephrolithotripsy Retrograde pyelogram
Tract formation for renal access

6. PCNL: what is it?
Stone fragmentation & retrieval

7. Indications PCNL is the preferred treatment for Large stone burden
2 cm or 1.5 cm for lower calyceal stones
Staghorn stones
Stones that are difficult to disintegrate by ESWL (calcium-oxalate monohydrate, brushite, cystine)
Stones refractory to ESWL or ureteroscopy
Urinary tract obstructions that need simultaneous correction (e.g. PUJ obstruction)
Malformations with reduced probability of fragment passage after ESWL (e.g. horseshoe or dystopic kidneys, calyceal diverticula)
Obesity
EAU Guidelines on Urolithiasis 2001

8. Imaging modalities for percutaneous access
Image guided
Fluoroscopy
USG

9. Imaging modalities for percutaneous access
Fluoroscopy
Most commonly employed
Use of 2-plane fluoroscopy to achieve accurate needle entry
Radiation safety: patient, surgeons, staff

10. Imaging modalities for percutaneous access
Ultrasonography:
The simplest & most direct
Minimises radiation exposure
Allows imaging of intervening structures between skin and kidney
Sonographic identification of the puncture needle may be technically demanding
Inability to clearly visualise and manipulate a guidewire once it is placed through the percutaneous access tract

11. Dilatation of the nephrostomy tract
Progressive fascial dilators
Metal coaxial dilators
Balloon dilation catheters

12. Dilation of the nephrostomy tract
Fascial dilators
Progressively larger Teflon tubes designed to slide over a inch GW
Size ranging from 8 to 36 Fr
Inserted in a rotating, screw-type fashion
Advantages:
Safe
Ideal for dilation of fibrous tracts
Disadvantages:
Dependence on the integrity of the GW

13. Dilation of the nephrostomy tract
Metal coaxial dilators
Stainless steel, mounted together in a telescopic fashion
8 Fr hollow guide rod that slides over a GW
A set of six metal tubes ranging in diameter from 9 to 24 Fr, each adapting exactly to the lumen of the next dilators

14. Dilation of the nephrostomy tract
Balloon dilation catheters
To achieve tract dilation in a single step
Avoid the need for serial dilation
Generate lateral compressive forces, theoretically less traumatic
Drawback: relative inability to dilate dense fascial tissue or scar tissue

15. Mini-perc technique Use of 13 to 20 Fr tract
Smaller volume of renal parenchyma dilated, leading to decrease in blood loss and post-op pain
Lahme et al Eur Urol. 40(6):619-24

16. Stone fragmentation Electrohydraulic Lithotripsy
Fragments stones with shock waves generated by an underwater electrical discharge
Narrow margin of safety owing to the risk of damage to ureteral mucosa and ureteral perforation

17. Stone fragmentation Holmium:YAG laser lithotripsy
Occurs primarily through a photothermal mechanism that causes stone vaporisation
Highly absorbed by water
Zone of thermal injury associated with laser ablation ranges from 0.5 to 1.0 mm
Able to fragment all stones
regardless of composition

18. Stone fragmentation Ballistic Lithotripsy A “jackhammer” effect
Swiss LithoClast
Effective means for stone fragmentation in the entire urinary tract with wide margin of safety
Relatively high rate of stone propulsion

19. Stone fragmentation Ultrasonic lithotripsy
Probe tip causes the stone to resonate at high frequency and break
When placing it on compliant tissues such as the urothelium, damage is minimal because the tissue does not resonate with the vibrational energy

20. Minimally Invasive PCNL (MPCNL) according to the Chinese Method: A Comparison with Traditional PCNL
CW Wong, TC Fung, CW Fan, SM Hou, SK Li
Division of Urology, Department of Surgery
Pamela Youde Nethersole Eastern Hospital
Hong Kong

21. Chinese MPCNL Minimally invasive PCNL, according to the Chinese method
First described by Lahme, Germany in 2001
Eur Urol. 40(6):619-24
The term Chinese MPCNL
Coined by Dr SK Li, PYNEH at ELSA 2005
Based on the approach described by Professor Li Xun, Guangzhou, China

22. Essential features Puncture: Stone fragmentation: Stone removal:
Kidney puncture based on pre-op imaging and tactile feedback
Minimal use of fluoroscopy
Size Fr 18 tract
Stone fragmentation:
LithoClast® (using 1 mm probe)
Stone removal:
Mainly by retrograde saline flushing

23. Puncture & tract dilatation
12th rib
11th rib
puncture site in 11th
intercostal space
Patient in prone position

24. Miniaturized endoscope
Olympus® slim compact cystoscope

25. Pressurized irrigation
350mmHg

26. Access to all calyces & ureter

27. MPCNL: the technique

28. Method Patients Statistical analysis
16 consecutive cases of staghorn stones
Underwent Chinese MPCNL by one single Surgeon
Statistical analysis
Results were retrospectively compared to that of the last 20 cases of traditional PCNL using Fr sheath

29. Results – stone characteristics
Chinese MPCNL
PCNL
Stone diameter (cm)
3.79  1.3
3.36  0.94
Stone area (mm²)
784.8
926.3
Type n (%)
Borderline
5 (31)
13 (65)
Partial
9 (56)
5 (25)
Complete
2 (13)
2 (10)

30. Results – operative parameters & outcome
Chinese MPCNL
PCNL
OR time (minutes)
94.7
122
Length of stay (day)
6.7
7.6
Stone clearance n (%)
Complete
8 (50)
12 (60)
Residual ≤ 4 mm
2 (12.5)
2 (10)
Residual > 4 mm
6 (37.5)
6 (30)
Auxiliary treatment 5 6

31. Results - complications
Chinese MPCNL
PCNL
Complications n (%)
Transfusion
1 (6.3)
5 (25)
UTI
2 (10)
Pleural effusion
TOTAL
3 (18.9)
7 (35)

32. Advantages of Chinese MPCNL
Miniaturised endoscope allows good calyceal and ureteric access even with middle calyceal puncture
Middle calyceal puncture at 11th intercostal space avoids risk associated with supra-11th upper pole calyceal puncture
A Fr 18 percutaneous tract minimises trauma with less blood loss

33. Conclusion
PCNL is a good and valuable method for removal of renal calculi
Different techniques of percutaneous renal access, tract dilation and stone fragmentation have been developed
Mini-perc is an evolving PCNL technique
An effective treatment option even for staghorn stone
Good stone clearance
Good calyceal and ureteric access
A safe option
Reducing trauma
Less transfusion requirement

36. The needle is being advanced with the C-arm at 30 degrees
The needle is being advanced with the C-arm at 30 degrees. A, Use of a clamp to reduce radiation exposure to the hands of the urologist. B, The C-arm is rotated back to the vertical position, and the depth of the needle is ascertained.