Bilateral urolithiasis is not an uncommon problem. Several studies have demonstrated the safety of same-session bilateral treatment with bilateral percutaneous nephrolithotomy (PCNL) and/or ureteroscopy (URS).^1-7 In an appropriately selected patient, these studies suggested performing same-session bilateral treatment of urolithiasis yields comparable stone-free and complication rates to staged procedures. This approach provides multiple advantages, including a single anesthetic, shorter cumulative operative time, fewer days in the hospital, and reduced cost. When performing a PCNL, the presence of a contralateral ureteral stone in a patient would compel most physicians to treat bilaterally, in efforts to alleviate or prevent symptoms. Recent findings from a multicenter, randomized, controlled trial further support bilateral treatment in the setting of a contralateral, asymptomatic renal stone.⁸ The proactive treatment of asymptomatic contralateral stones was associated with a 75% lower incidence of stone relapse and a longer time to relapse without significant operative or perioperative morbidity compared to observation.⁸

A survey conducted by Rivera et al. revealed 85% of endourologists were willing to perform bilateral simultaneous (BL-S) URS under the same anesthetic; however, only 38% had previously performed BL-S PCNL. For those respondents who did not perform bilateral PCNL, 10% would offer unilateral PCNL and contralateral URS as an alternative treatment option for patients.⁹ This approach is optimal for patients with a large-volume stone burden on the planned PCNL side and a small- or intermediate-size contralateral stone burden (Figure 1).⁹ This is a particularly attractive option for symptomatic patients on the contralateral side or those asymptomatic patients in whom there is a desire to reduce the likelihood of future stone events. Shared decision-making is crucial, and the factors influencing the surgical feasibility should be thoroughly evaluated.

Figure 1. CT image of large (2.2 cm) right-sided stone burden and small (7 mm) left-sided stone burden.

Patient positioning and available equipment determine the feasibility of BL-S PCNL and URS. There is growing attention to the benefits of supine positioning for PCNL, including the ability to simultaneously access the contralateral renal unit; however, the majority of surgeons in the United States perform PCNL in the prone position. A split-legged prone operating table can facilitate simultaneous percutaneous treatment, while also performing contralateral treatment via retrograde URS. Setup for simultaneous bilateral treatment does not add a significant amount of preparation time and can allow 2 surgeons to operate in tandem for patients in the prone position. The equipment necessary for simultaneous bilateral treatment includes 2 cameras and/or digital scopes, 2 irrigation setups, and at least 2 monitors; thus, feasibility of this somewhat resource-heavy procedure is institution dependent (Figure 2).

Figure 2. Split-legged prone table operative setup for tandem bilateral surgery. PCNL indicates percutaneous nephrolithotomy.

Simultaneous bilateral treatment has been shown to have shorter cumulative operative times compared to staged procedures. A comparative study by Shen et al. showed a shorter overall operative time when comparing BL-S PCNL and URS to staged treatment of patients with staghorn calculi and contralateral ureteral stones (123 vs 141 minutes).⁴ Moreover, 2 experienced surgeons can operate concurrently, reducing operative time even further. Giusti et al demonstrated a mean operative time of 79 minutes when performing BL-S PCNL and URS operating on both renal units simultaneously.³ While a shorter operative time is an important factor, the safety and efficacy of a simultaneous bilateral approach are of paramount importance.

With regard to efficacy, BL-S PCNL and URS have been shown to have stone-free rates as high as 92% and most importantly are comparable to a staged approach.^2,4,7 However, the definitions of stone-free vary in the literature, which limits its utility as a primary outcome measure.

When evaluating safety, the increased operative time under a single anesthetic and operating on both renal units have the potential to increase complications. Minor and major complication rates have been reported at 22% and 1.4% for BL-S URS, and 27% and 6.4% for BL-S PCNL, respectively.¹⁰ Comparative and prospective studies for BL-S PCNL and URS remain limited. Although only small studies have been reported, overall complications ranged from 11%-18% with a 1% rate of major complications (Clavien grade III or higher).^3,4,7 Moreover, much of the literature on BL-S PCNL, URS, or PCNL+URS reports on a case basis, rather than per renal unit, which can potentially overestimate the reported complications. While the safety and efficacy of BL-S PCNL and URS appear to be comparable to a staged approach, the impact of BL-S treatment on patient quality of life has not been investigated. This area not only warrants future investigation, but also should be included in preoperative counseling with patients.

Given these considerations, tailoring the approach to each individual patient is critical. Shared decision-making after determining the surgical feasibility and potential advantages for BL-S PCNL and URS is of utmost importance. To guide this process, ideal candidates for BL-S PCNL and URS should have favorable calyceal anatomy with anticipated single-tract access, predicted operative time of less than 3 hours, limited comorbidities, favorable overall renal function, and successful completion of surgery on the first planned side without complications.

A combined BL-S PCNL and URS approach for patients with bilateral urolithiasis can achieve high stone-free rates, potentially shorter operative times, and a similar safety profile to other BL-S urolithiasis surgeries and staged approaches, though further investigations particularly focused on describing patient quality of life are warranted.