Could saline irrigation clear all residual common bile duct stones after lithotripsy? A self-controlled prospective cohort study

Table 1 Clinical and procedural characteristics of the patients

Patients	n = 47
Age (yr, mean ± SD)	61 ± 16.5
Male	23 (48.9%)
Stone size (mm)	14 (14-15)
Multiple CBD stones	36 (76.6%)
Diameter of CBD (mm)	15 (12-18)
Gallbladder stones	21 (44.7%)
Previous cholecystectomy	24 (51.1%)
Periampullary diverticulum	15 (31.9%)
Total bilirubin (µmol/L)	71.1 (64.9-107.9)
Comorbidities
Coronary disease	3 (6.4%)
Hypertension	14 (29.8%)
Diabetes	2 (4.3%)
Liver cirrhosis	3 (2.1%)
Portal hypertension	1 (6.4%)
ENBD	40 (85.1%)
Procedure time, min (mean ± SD)	40.3 ± 15.4
Stone texture
Hard stones	16 (34.0%)
Soft stones	31 (66.0%)
Stone compositions
Cholesterol-based stones	17 (36.2%)
Pigment-based stones	30 (63.8%)
Procedure-related adverse events
Cholangitis	4 (8.5%)
Oozing	2 (4.3%)
Pancreatitis	4 (8.5%)
Cholecystitis	1 (2.1%)
Perforation	0
Death	0

Data are expressed as the mean ± SD, median (interquartile range) or n (%). ENBD: Endoscopic nasobiliary drainage; CBD: Common bile duct.

Table 2 Common bile duct clear score and stone clearance rate before and after saline irrigation

Score	No irrigation	50 mL	100 mL	P value
Score 1	13 (28%)	0 (0%)	0 (0%)
Score 2	8 (17%)	4 (8%)	0 (0%)
Score 3	19 (40%)	15 (32%)	3 (6%)
Score 4	7 (15%)	28 (60%)	12 (26%)
Score 5	0 (0%)	0 (0%)	32 (68%)
Clear	7 (15%)	28 (60%)	44 (94%)	< 0.001

Table 3 Biliary cleanliness before and after saline irrigation, assessed by logistic regression analysis

		Residual massive stones (score = 1) before saline irrigation					Biliary clearance (score = 5) after 100 mL saline irrigation
	n/N	Univariable analysis	Multivariable analysis	n/N	Univariable analysis	Multivariable analysis
		OR (95%CI)	P value	OR (95%CI)	P value		OR (95%CI)	P value	OR (95%CI)	P value
Age
≤ 65 yr	6/27	1.00		19/27		19/27	1.00		-
> 65 yr	7/20	1.89 (0.52-6.86)	0.34	13/20		13/20	0.78 (0.23-2.69)	0.70	-	-
Gender					-
Female	9/24	1.00		16/24		16/24	1.00		-
Male	4/23	0.35 (0.09-1.37)	0.13	16/23	0.17	16/23	1.14 (0.34-3.90)	0.83	-	-
CBD diameter
≤ 15 mm	5/32	1.00		26/32		26/32	1.00		1.00
> 15 mm	8/15	6.17 (1.53-24.84)	0.01	6/15	0.034	6/15	0.15 (0.04-0.60)	0.007	0.08 (0.01-0.49)	0.007
Stone number
Single	3/11	1.00		10/11		10/11	1.00		1.00
Multiple	10/36	1.03 (0.23-4.66)	0.97	22/36	-	22/36	0.16 (0.02-1.37)	0.09	0.08 (0.01-1.09)	0.06
Stone diameter
≤ 15 mm	8/36	1.00		26/36		26/36	1.00		-
> 15 mm	5/11	2.92 (0.70-12.11)	0.14	6/11	0.34	6/11	0.46 (0.12-1.86)	0.28	-	-
Pigment-based stones
No	4/17	1.00		14/17		14/17	1.00		1.00
Yes	9/30	1.39 (0.36-5.46)	0.63	18/30	-	18/30	0.32 (0.08-1.36)	0.12	0.43 (0.05-3.60)	0.44
PAD
No	4/15	1.00		26/32		26/32	1.00		1.00
Yes	9/32	1.08 (0.27-4.28)	0.92	6/15	-	6/15	6.50 (1.67-25.38)	0.007	6.51 (1.08-39.21)	0.041

N: Total number; CBD: Common bile duct; PAD: Periampullary diverticula; CI: Confidence interval; OR: Odds ratio.

Table 4 Correlation between the composition of stones and variables

Variable	Pigment-based stones	Cholesterol-based stones		P value
PAD
Yes	14 (93.3%)	1 (6.7%)	8.31	0.004
No	16 (50.0%)	16 (50.0%)
Diameter of the CBD
≤ 15 mm	21 (65.6%)	11 (34.4%)	0.14	0.75
> 15 mm	9 (60.0%)	6 (40.0%)
Diameter of the stone
≤ 15 mm	25 (69.4%)	11 (30.6%)	2.10	0.17
> 15 mm	5 (45.5%)	6 (54.5%)
Stone texture
Hard	6 (37.5%)	10 (62.5%)	7.28	0.01
Soft	24 (77.4%)	7 (22.6%)

CBD: Common bile duct; PAD: Periampullary diverticula.