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

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

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

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

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

PCNL: what is it? Stone fragmentation & retrieval

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

Imaging modalities for percutaneous access Image guided Fluoroscopy USG

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

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

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

Dilation of the nephrostomy tract Fascial dilators Progressively larger Teflon tubes designed to slide over a 0.038 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

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

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

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

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

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

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

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

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

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

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

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

Miniaturized endoscope Olympus® slim compact cystoscope

Pressurized irrigation 350mmHg

Access to all calyces & ureter

MPCNL: the technique

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 24-28 sheath

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)

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

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

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

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

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.