Factors Impacting Stone-Free Rate After Retrograde Intrarenal Surgery for Calyceal Diverticular Calculi

Figures & data

Figure 1 A refluxing technique with methylene blue was used to identify the diverticular opening. (A) Suspected opening. (B) Refluxing of methylene blue through the opening.

Figure 2 At the end of the procedure, a contrast study was performed and a double-J stent was retained inside the diverticulum. (A) Diverticular neck after widening. (B) Upper coil of double-J stent was in the diverticulum.

Table 1 Demographic Data

Characteristics	Numbers
Sex
Male; n (%)	10 (31.3)
Female; n (%)	22 (68.8)
Age; mean (min–max)	55.7 years (28–77)
Stone positions
Non-lower pole; n (%)	26 (81.2)
Lower pole; n (%)	6 (18.8)
Stone size; median (min– max)	1.2 cm (0.3– 10.5)
Number of stones; median (min–max)	3 (1–10)
Stone compositions
Calcium oxalate; n (%)	18 (56.3)
Calcium phosphate; n (%)	8 (25)
Uric acid; n (%)	2 (6.3)
No data; n (%)	4 (12.5)
Diverticulum positions	Stone size
Anterior; n (%); median (min–max)	11 (34.4); 1.2 cm (0.5–10.5)
Posterior; n (%)	16 (50); 1.6 cm (0.5–4.0)
Unknown; n (%)	5 (15.6); 0.7 cm (0.3–1.6)
Length of diverticulum; mean (min–max)	0.4 cm (0.2–1.2)
Operative time; mean (min–max)	46 minutes (15–90)
Hospital stay; mean (min–max)	2.9 days (1–14)
Complications; n (%)	5 (15.6)
Follow-up time; mean (min–max)	2.3 weeks (2–4)
Stone-free; n (%)	24 (75)

Table 2 Complications

Complication	Incidence
Fever; n (%)	3 (9.3)
Sepsis; n (%)	2 (6.3)

Figure 3 The length of the diverticular neck was measured from the opening to the diverticulum.

Figure 4 ROC curve, optimal cut-off point of stone size.

Figure 5 ROC curve, optimal cut-off point of diverticulum neck length.

Table 3 Outcomes

	Stone Free	Residual Stone	P-value
Stone position			0.625
Non-lower pole; n (%)	20 (76.9)	6 (23.1)
Lower pole; n (%)	4 (66.7)	2 (33.3)
Stone size			0.003
<1.5 cm; n (%)	18 (94.7)	1 (5.3)
≥1.5 cm; n (%)	6 (46.2)	7 (53.8)
Diverticulum position			1.000
Anterior; n (%)	8 (72.7)	3 (27.3)
Posterior; n (%)	12 (75.0)	4 (25.0)
Diverticular neck length			0.038
<0.4 cm; n (%)	17 (89.5)	2 (10.5)
≥0.4 cm; n (%)	7 (53.8)	6 (46.2)

Table 4 Multivariate Analysis of the Factors Affecting the Stone-Free Rate

	Adjusted OR	95% CI	P-value
Stone size
≥1.5 cm	1 (ref)
<1.5 cm	21.00	(1.82–242.32)	0.015
Diverticular neck length
≥0.4 cm	1 (ref)
<0.4 cm	7.29	(0.83–63.79)	0.073

Abbreviations: OR, odds ratio; CI, confidence interval; ref, reference.