Haroon N et al, 2013: Optimal Management of Lower Polar Calyceal Stone 15 to 20 mm
Haroon N, Nazim SM, Ather MH
Department of Surgery, Aga Khan University, Karachi, Pakistan
PURPOSE: To compare the stone clearance rate, efficiency quotient (EQ), and early complications of shock wave lithotripsy (SWL) and percutaneous nephrolithotomy (PCNL) for solitary lower-pole renal stones measuring 15 to 20mm.
MATERIALS AND METHODS: This was a retrospective matched-pair analysis of 142 patients (78 in the SWL and 64 in the PCNL group). Preoperative imaging was done by use of noncontrast computed tomography (CT kidney, ureter, and bladder [KUB]), intravenous urogram, or plain X-ray and ultrasound KUB to assess the largest dimension of the stones. Only patients with radiopaque stones were included. The stone-free rates were assessed with plain X-ray and ultrasound at 4 weeks. Data were analyzed by use of SPSS ver. 19.
RESULTS: The patients' demographic profiles (age, body mass index) and the stone sizes were comparable in the two groups. The mean stone size was 17.4±2.12 in the PCNL group compared with 17.67±2.04 in the SWL group (p=0.45). At 4 weeks, 83% of patients undergoing PCNL were stone-free compared with 51% in the SWL group (p<0.001). The EQ for the PCNL group was 76% compared with 44% for the SWL group (p<0.001). Ancillary procedures were required by 9% of patients in the PCNL group compared with 15% in the SWL group. The complication rate was 19% in both groups. The SWL complications were minor.
CONCLUSIONS: Stone clearance from the lower pole of solitary stones sized 15 to 20 mm at the greatest diameter following SWL is poorer. These calculi can be better managed with percutaneous surgery owing to its higher efficacy and acceptably low morbidity.
Korean J Urol. 2013 Apr;54(4):258-62. doi: 10.4111/kju.2013.54.4.258. Epub 2013 Apr 16.
PMID:23614064[PubMed] PMCID:PMC3630346. FREE ARTICLE
That stone clearance following PCNL is better than that after SWL and that the difference is related to the size of treated stones is well recognized and, as also shown by the authors, repeatedly reported in the literature. It thus stands to reason that if SWL is not carried out in any specific way, with modified lithotripters or associated with any effective auxiliary measure, there seems to be little need for further studies to emphasize this difference.
It is noteworthy that in a population of >2600 SWL-treated patients only 3% fulfilled inclusion criteria. This is indeed slightly surprising in view of the fact that most stones in the kidney can be expected to be located in the lower calyx. Moreover, it is my own impression that a mean of 3 sessions is high for stones with an average diameter of 17 mm, and none larger than 20 mm.
Of interest is that the need of auxiliary procedures was the same for patients treated with SWL and PCNL. Although URS very often is considered necessary for treating patients with steinstrasse it is my own experience that the vast majority of patients with steinstrasse can be managed by repeated SWL with or without simultaneous stent Insertion.
Despite complications at a similar level for both procedures, the more serious ones were recorded after PCNL.
It would indeed be highly interesting to learn more about the further course of the residual fragment beyond one week. Too few studies give any information on this important question.
This as well as numerous other studies have shown that for the greater stone-free rate with PCNL the price that has to be paid is more serious complications and the need anesthesia.