Table 4. Details of weighted cumulative mean and risk of outcomes in USS group and conventional group.

Outcomes	Study	References	USS group		Conventional group		Weighted mean difference(95% CI)	P value
	counts		Patients	WCM/WCR	Patients	WCM/WCR
OT (min)	14	[19]–[23], [25]–[29], [31], [34]–[36]	736	151.0	777	185.3	−33.30 (−41.75, –24.86)	<0.001
POC (n)	9	[19]–[21], [27], [29]–[31], [36]–[37]	359	0.089	402	0.129	Not applicable	Not applicable
BL (ml)	15	[19]–[23], [25]–[29], [31], [33]–[36]	771	111.6	805	217.9	−113.42 (−142.05, –84.79)	<0.001
NDLN (n)	13	[19, 22–25, 27–31, 33–34,36–36]	977	20.2	903	18.9	2.48 (1.02, 3.94)	<0.001
POHD(days)	3	[20], [22], [29]	96	11.3	112	13.1	−1.69 (−2.27, –1.12)	<0.001
NTP (n)	3	[20]–[21], [37]	76	0.18	76	0.36	Not applicable	Not applicable
AD (ml)	7	[22]–[24], [26]–[27], [32]–[33]	413	199.2	401	302.8	−96.67 (–119.26, –74.09)	<0.001
GIFRD (days)	6	[19], [25], [28]–[29], [34]–[35]	363	3.1	405	4.0	−0.94 (–1.20, –0.64)	<0.001

Abbreviations: USS: ultrasonic scalpel; OT: operation time; POC: postoperative complications; BL: blood loss in operations; NDLN: number of dissected lymph nodes; POHD: postoperative hospitalization days; NTP: number of transfusion patients; AD: abdominal drainage; GIFRD: gastrointestinal function recovery days; WCM: weighted cumulative mean; WCR: weighted cumulative risk.