Assistant skill in gastric endoscopic submucosal dissection using a clutch cutter

Table 1 Characteristics of the mock lesions treated by endoscopic submucosal dissection with a clutch cutter

	All, n = 32	Expert, (ESD-C-E), n = 16	Non-expert, (ESD-C-NE), n = 16	P value
Location, n (%)				0.72
Middle third	20 (62.5)	9 (56.2)	11 (68.8)
Lower third	12 (37.5)	7 (43.8)	5 (31.2)
Position, n (%)				0.61
Anterior wall	9 (28.1)	4 (25.0)	5 (31.2)
Posterior wall	4 (12.5)	1 (6.2)	3 (18.8)
Greater curvature	19 (59.4)	11 (68.8)	8 (50.0)
Marking size, mm2				0.75
mean ± SD	391.64 ± 288.63	408.54 ± 264.49	374.74 ± 318.76
Median (IQR)	310.86 (184.08-461.78)	314.00 (219.80-515.16)	310.86 (175.84-407.42)

P value was calculated using Fisher’s exact test and the Mann-Whitney U test. ESD: Endoscopic submucosal dissection; ESD-C: ESD using a clutch cutter; ESD-C-E: ESD-C assisted by an expert; ESD-C-NE: ESD-C assisted by a non-expert; IQR: Interquartile range; SD: Standard deviation.

Table 2 Treatment outcomes of the endoscopic submucosal dissection with a clutch cutter

	Expert (ESD-C-E), n = 16	Non-expert, (ESD-C-NE), n = 16	P value
En bloc resection, n (%)	16 (100)	16 (100)	-
Complete procedure, n (%)	16 (100)	15 (93.8)	1
Perforation, n (%)	0 (0)	0 (0)	-
Total procedure time, min
mean ± SD	13.90 ± 4.49	24.31 ± 11.24	0.001a
Median (IQR)	12.93 (10.79-15.33)	21.90 (18.50-26.36)
Incision time, min			< 0.001a
Median (IQR)	7.04 (5.57-8.28)	11.70 (10.75-13.23)
Dissection time, min			0.07
Median (IQR)	3.20 (2.18-5.17)	5.09 (3.50-9.91)
Circumferential length, mm			0.88
Median (IQR)	74.85 (68.62-93.11)	75.46 (66.73-86.59)
Resected area, mm2			0.78
Median (IQR)	437.50 (324.75-688.50)	451.00 (304.00-589.00)
Incision speed, mm/min			0.001a
Median (IQR)	11.24 (9.61-12.94)	6.72 (5.63-9.13)
Dissection speed, mm2/min			0.019a
Median (IQR)	137.30 (120.17-167.72)	75.66 (52.57-135.88)

^aSignificant value. P-value was calculated using Fisher’s exact test and the Mann-Whitney U test. ESD: Endoscopic submucosal dissection; ESD-C: ESD using a clutch cutter; ESD-C-E: ESD-C assisted by an expert; ESD-C-NE: ESD-C assisted by a non-expert; IQR: Interquartile range; SD: Standard deviation.

Table 3 Factors associated with the difficulty of endoscopic submucosal dissection

	No. of patients	No. of events	Univariate			Multivariatea
			OR	95%CI	P value	OR	95%CI	P value
Location					0.52			0.49
Middle third	20	9	1.64	0.37-7.25		2.09	0.17-12.3
Lower third	12	4	1	Reference		1	Reference
Position					0.60			0.73
Non-GC	13	6	1.47	0.35-6.17		0.68	0.08-5.73
GC	19	7	1	Reference		1	Reference
Assistant skill					0.016a			0.021a
Non-expert	16	10	7.22	1.44-36.20		16.5	1.52-178.00
Expert	16	3	1	Reference		1	Reference
Resected area					0.025a			0.023a
≥ 500 mm2	12	8	6.00	1.25-28.8		15.3	1.46-159.00
< 500 mm2	20	5	1	Ref.		1

^aSignificant value. Adjusted for all factors in this table. ESD: Endoscopic submucosal dissection; ESD-C: ESD using a clutch cutter; GC: Greater curvature; No: Number; OR: Odds ratio.