The aim of this study is to compare outcomes of endoscopic combined intrarenal surgery (ECIRS) with the multi-tract percutaneous nephrolithotomy for management of complex renal stones.

Nephrolithiasis is a very common disease and continues to be a common cause of morbidity. The evolving epidemiology of this disease includes changes in gender distribution and associations with systemic disease. The currently available modalities for the treatment of renal calculi include extracorporeal shockwaves lithotripsy (SWL), flexible ureteroscopy (FURS) and percutaneous nephrolithotomy (PCNL).

Complex renal stones usually refer to multiple stones, stones associated with anatomical or functional abnormalities or staghorn calculi. They can cause severe morbidities such as renal failure, sepsis, and even death. Rassweiler et al. defined complex renal calculi based on stone burden and distribution, renal function and associated infection. Due to the complicated etiological factors, large stone burdens, high operation risks and high recurrence, it is always a challenge for surgeons to treat such stones. Complete stone clearance is the ultimate goal in staghorn calculi management because of the high incidence of recurrence and its inherent risks to the kidney and life of the patient.

Various management options are available for management of staghorn renal calculi including PCNL monotherapy, single-tract PCNL with flexible nephroscopy, multi-tract PCNL, combinations of PCNL and SWL, SWL monotherapy and open surgical options.

The American Urological Association (AUA) guidelines recommend PCNL as the first-line treatment for staghorn calculi. According to the European Association of Urology (EAU) guidelines, SWL remains the method of choice for the removal of stones within the renal pelvis, upper or middle calices measuring < 2 cm while larger stones (more than 2 cm) and lower pole stones more than 1.5 cm should be managed using PCNL.

It is noteworthy that prone position is conventionally used for PCNL surgical procedure, which facilitates percutaneous renal puncture and decreases the chance of splanchnic injury. However, it confines the application of Endoscopic Combined Intra-Renal Surgery (ECIRS). Scoffone CM et al. reported the use of ECIRS in Galdakao-Modified Supine Valdivia (GMSV) position for complex urolithiasis, the results showed that ECIRS in GMSV position generated high one step SFR, without additional procedure related complications.

As stone size increases, longer operative time, larger volume of irrigating fluid and multiple tracts may be required to achieve complete stone clearance as it is very difficult to access all the calices through a single percutaneous tract. Multiple access tracts are needed in as many as 20% to 58% of PCNL procedures.In case of complex calculi, the number of accesses is defined by the overall size, volume of the stone, anatomy of the pelvi-calyceal system (PCS), stone distribution, general health of the patient and the experience of the operating surgeon. So, multi-tract PCNL has been well established in the management of complex renal calculi. El-Nahas AR et al. reported that with PCNL monotherapy, the stone free rate (SFR) for staghorn calculi was 56%.Multiple tracts or multiple sessions of PCNL were required to get high SFR in patients with staghorn calculi while the tract related complications increased accordingly such as extravasation, bleeding, need for transfusion, infection, fever and deterioration in renal function. Indeed, several investigators have reported greater blood loss with more than one access tract.

On the other hand, many evidences have demonstrated that FURS is effective and safe for the renal stone less than 2 cm. Recently it is used to treat relatively large size intrarenal calculi . A meta-analysis published in 2012 showed that FURS can successfully treat patients with renal stones > 2 cm with satisfactory clinical outcome. However, flexible ureteroscopic lithotripsy is not recommended as monotherapy for staghorn calculi, while an important ancillary therapeutic option for residual stones following PCNL.

So, we need a new treatment modality to minimize the morbidity of multi-tract PCNL by evaluation of the ECIRS.

Inclusion Criteria:

• Patients' age ≥ 18 years.
• Patients who are diagnosed as complex renal calculi (Guy's Stone Score (GSS) 3 or 4) as detected by Non-contrast Computed Tomography (NCCT).

Exclusion Criteria:

• Renal anatomic anomalies.
• Solitary kidney.
• Coagulation disorders.
• Skeletal deformity.
• Active urinary tract infection.