Comparison of Mini-Percutaneous Nephrolithotomy and Retroperitoneal Laparoscopic Ureterolithotomy for Treatment of Impacted Proximal Ureteral Stones Greater Than 15 mm
Impacted proximal ureteral stones, defined as stones lodged in the upper ureter for over two months, pose significant clinical challenges due to their tendency to adhere to the ureteral wall, obstruct urine flow, and induce complications such as hydronephrosis, infection, and ureteral polyps. Traditional treatments like extracorporeal shockwave lithotripsy (SWL) and ureteroscopic lithotripsy (URS) often yield suboptimal results for large (>15 mm) impacted stones, necessitating alternative approaches such as mini-percutaneous nephrolithotomy (MPCNL) and retroperitoneal laparoscopic ureterolithotomy (RPLU). This study evaluates the efficacy, safety, and recovery profiles of these two surgical techniques for managing such complex cases.
Patient Demographics and Study Design
A retrospective analysis was conducted on 268 patients treated between January 2014 and January 2019, with 126 undergoing MPCNL and 142 undergoing RPLU. Inclusion criteria targeted patients with solitary proximal ureteral stones >15 mm confirmed via imaging (KUB plain film or NCCT) and persistent for ≥2 months. Exclusions included prior ipsilateral renal/ureteral surgery, distal ureteral/kidney stones, active infections, or comorbidities precluding anesthesia. Preoperative assessments included ultrasound for hydronephrosis severity, urine culture, and laboratory tests. Both groups exhibited comparable baseline characteristics: mean stone size (MPCNL: 16.6 ± 1.4 mm vs. RPLU: 16.8 ± 1.7 mm), hydronephrosis severity (22.3 ± 5.5 mm vs. 24.3 ± 6.3 mm), age, BMI, and gender distribution.
Surgical Techniques
MPCNL Procedure
Under general anesthesia, patients were initially placed in lithotomy position for cystoscopic insertion of a 6-Fr ureteral catheter. Transitioning to prone position, an 18-gauge needle was percutaneously inserted into the middle calyx under ultrasound guidance. Sequential dilation to 16 Fr facilitated placement of a peel-away sheath. A rigid 8/9.8-Fr ureteroscope and Holmium laser (60 W, 550 μm fiber) fragmented stones, with debris flushed via endoscopic perfusion. A 16-Fr nephrostomy tube was placed postoperatively.
RPLU Procedure
Performed under general anesthesia via three retroperitoneal ports (10 mm at mid-axillary line, 10 mm and 5 mm at anterior/posterior axillary lines). The ureter was isolated, clamped proximal to the stone, and incised for extraction. A 6-Fr double-J (DJ) stent was inserted, and the ureterotomy closed with 4-0 Vicryl sutures. An 18-Fr retroperitoneal drain was placed, removed after three days if no leakage occurred.
Outcomes and Comparative Analysis
Surgical Success and Stone-Free Rates
Both techniques demonstrated high efficacy: RPLU had marginally higher surgical success (97.9% vs. 96.0%) and one-month stone-free rates (97.9% vs. 94.4%), though differences were statistically insignificant (P = 0.595 and P = 0.245, respectively*). Failures in MPCNL (n=5) included two conversions to RPLU due to ureteral distortion and three staged procedures for purulent urine. RPLU failures (n=3) involved stone migration requiring conversion to open surgery (n=1) or flexible ureteroscopy (n=2).
Operative and Recovery Metrics
MPCNL outperformed RPLU in operative efficiency and recovery:
- Operative Time: 68.2 ± 12.5 vs. 87.2 ± 16.8 minutes (P = 0.041).
- Hospital Stay: 2.2 ± 0.6 vs. 4.8 ± 0.9 days (P < 0.001).
- DJ Stent Duration: 3.2 ± 0.5 vs. 3.9 ± 0.8 weeks (P = 0.027).
- Catheterization Time: 1.1 ± 0.3 vs. 3.5 ± 0.5 days (P < 0.001).
- Drainage Tube Removal: 2.3 ± 0.3 vs. 4.6 ± 0.6 days (P < 0.001).
MPCNL patients required fewer postoperative analgesics (1.7% vs. 9.4%, P = 0.017), attributed to minimized tissue trauma. Hemoglobin drop was comparable (0.8 ± 0.6 vs. 0.4 ± 0.2 g/dL, P = 0.621), with no transfusions needed in either group.
Complications
Overall complication rates were similar (16.5% vs. 22.3%, P = 0.242), predominantly Clavien Grade I–II:
- MPCNL: Fever >38°C (4.1%), perirenal hematoma (0.8%), DJ stent malposition (1.7%).
- RPLU: Urine leakage (5.8%), fever (0.7%), DJ stent malposition (5.8%).
Severe complications (Grade III) included ureteral stricture (MPCNL: 3.3% vs. RPLU: 0.7%), managed via laparoscopic repair. No Grade IV/V events occurred.
Long-Term Follow-Up
Over 12–46 months, ureteral stricture rates remained low (MPCNL: 3.3% vs. RPLU: 0.7%), reflecting durable outcomes. RPLU’s lower stricture risk may relate to avoiding thermal injury (Holmium laser in MPCNL vs. cold incision in RPLU).
Clinical Implications and Discussion
MPCNL and RPLU are equally effective for large impacted proximal stones, with success rates exceeding 94%. MPCNL offers advantages in operative speed, reduced hospitalization, and quicker recovery, attributed to smaller incisions and avoidance of ureteral suturing. Conversely, RPLU’s retroperitoneal approach minimizes pelvic pressure spikes, potentially lowering infection risks, though this study found no significant intergroup difference in febrile episodes.
MPCNL’s drawbacks include technical challenges in distorted ureters and laser-related thermal injury risks. RPLU, while avoiding renal puncture, demands advanced laparoscopic skills and entails longer operative times due to ureteral reconstruction. DJ stent malposition was more frequent post-RPLU (5.8% vs. 1.7%), necessitating secondary interventions.
Conclusion
For impacted proximal ureteral stones >15 mm, MPCNL and RPLU achieve comparable stone clearance and safety. MPCNL is preferable for rapid recovery and minimal invasiveness, whereas RPLU suits cases with complex anatomy or infection concerns. Surgeon expertise and patient-specific factors should guide modality selection.
doi.org/10.1097/CM9.0000000000001417
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