Percutaneous nephrolithotomy (PCNL) is a procedure to remove kidney stones when they are unable to pass on their own. This involves making a small incision on the back to remove the kidney stone that is too large (more than two cms), too many, or too dense to be treated by other stone removal methods such as extracorporeal shock wave lithotripsy (ESWL) or ureteroscopy. PCNL is a non-invasive method and an innovation on the previous open surgeries used to remove kidney stones which were far more complicated and invasive than PCNL.
Why is PCNL done?
A doctor will recommend Percutaneous Nephrolithotomy in following cases:
- Kidney stones larger in diameter than two cms
- Large kidney stones are causing increasing complications such as blocking more than one collecting branch of the kidney
- Presence of large stones in the ureter
- When other therapies have failed
Before recommending a PCNL for kidney stones, the doctor will conduct several tests, including blood and urine tests, to assess the present health condition of the patient. A CT scan can also be conducted to know the problem in-depth.
Risks of PCNL
The surgery has the following risks:
- Infection at the site of incision
- Damage or injury to the surrounding organs and tissues
- Injury to the kidney
- Incomplete removal of kidney stones
- Risk of conversion to open surgery (when reaching the stone become complicated due to unforeseen circumstances)
The procedure of the Surgery
The surgery is performed after influencing the patient with anaesthesia. The doctor makes a small incision on the back and inserts a tube through the incision into the kidney through X-ray guidance. Once the tube is in place, a telescope is passed through the tube to get a clear picture of the stone/stones, break the stone and then remove it from the body. In case, the stone is very large, a device called – lithotripter can be used to first break the stone before removing it. The surgery lasts for about three to four hours and has less postoperative complications, shorter recovery time and a shorter stay in hospital as compared to open stone surgery. The surgery has more success rates of clearing all stones as compared to an extracorporeal shock wave lithotripsy (ESWL).
That said, the techniques of kidney stone removal have seen immense advancement over time, from open surgery to more feasible and less invasive options such as percutaneous nephrolithotomy (PCNL), retrograde intrarenal surgery (RIRS), extracorporeal shock wave lithotripsy (ESWL), and laparoscopic surgery. Doctors increasingly relied on percutaneous nephrolithotomy (PCNL) and extracorporeal shock wave lithotripsy (ESWL) to remove large kidney stones and small kidney stones, respectively. However, with further progress in the field and the new generation of even more flexible surgical instruments, including ureteroscopes and lithotripters – Retrograde Intrarenal Surgery has increasingly been adopted to treat large kidney stones.
RIRS or Retrograde Intrarenal Surgery is an endoscopic surgery performed to remove renal stones by reaching the kidney from the ureter. RIRS procedure uses a viewing tube called fibre optic endoscope and a laser fibre – Holmium – to treat the renal stones. Once the large stone is removed, small fragments of the stones are taken off through stone baskets. In some cases, a stent may be pushed in the kidney to improve drainage. Post the procedure, the endoscope is crushed, blasted or evaporated by using a laser probe or can also be manually removed through forceps. The surgery is performed by a urologist who has specialized expertise in RIRS. During the procedure, the patient is given local, spinal or general anaesthesia and the endoscope is inserted in the body through the urethra then onto the kidney; the surgery does not involve any incisions and hence, has a very fast recovery time. With RIRS, a vast majority of renal stones can be cleared without open surgery.
Moreover, with the recent technological developments in the management of renal stones, RIRS has emerged as a very reliable, safe and efficient method. The main purpose of a renal stone treatment is to clear the stones completely with minimum morbidity – RIRS clears renal stones through flexible ureterorenoscopes and lithotripters including holmium laser, ensuring no trace of stones are left. Moreover, advancement in related types of equipment such as guide-wires, urethral access sheath and stone baskets have enhanced the effectiveness of the RIRS procedure. As of today, RIRS is a prime method of treatment for renal stones that are less than 2 cm and cannot be successfully treated via other methods.
RIRS procedure is best suited for cases where:
- Earlier attempts to remove renal stones have failed
- Stones are too large in size
- There is a tumour in the kidney
- There are strictures in the kidney
- The patient involved is a child
- The patient has bleeding disorders
- The patient is obese
- The patient has complex anatomical kidneys
- Patient is on anticoagulants
Risks of the Surgery
Complications or risks associated with RIRS are fairly uncommon and occur only in very cases.
- Flank pain
- Urinary infection
- Transient hematuria
- Acute urinary retention
- Ureteral pelvicalyceal abrasion
- Fornix rupture
- Ureter avulsion
- Trauma to kidneys
PCNL vs RIRS
That said, RIRS has increasingly become the first choice of doctors to treat patients that have kidney stones and considerable health conditions. Some basic points of difference between PCNL and RIRS are:
- Recovery time is more in PCNL than RIRS
- PCNL has more chances of post-operative complications than RIRS, including blood transfusion, multi-follow ups, etc.
- Stone free rate is higher in PCNL than RIRS after one session
- PCNL useful for stones larger than 2 cm; however, single or multi-session RIRS may be required to break stone larger than 2 cm
- RIRS is a longer procedure than PCNL
- Haemoglobin levels are less likely to drop after RIRS as compared to PCNL
- RIRS is best to use for stones lesser than 2 cm in size in morbidly obese patients, patients with musculoskeletal deformities, bleeding diatheses, and in cases of unsuccessful ESWL treatment previously. Thus, RIRS can be alternative in patients who need stone treatment (stone ranging 2-4 cm in diameter) but have health conditions.
That said, PCNL and RIRS need to be evaluated per case basis to decide which method is the best suited as per need of the patient.