Short-term efficacy of robotic and laparoscopic spleen-preserving splenic hilar lymphadenectomy via Huang's three-step maneuver for advanced upper gastric cancer: Results from a propensity score-matched study

Table 1 General clinical and pathological data of patients

Variable	All patients					Propensity score matching
	RSPSHL		LSPSHL		P-value	RSPSHL		LSPSHL		P-value
	(n = 35)	%	(n = 608)	%		(n = 35)	%	(n = 140)	%
Age, yr1	55.3 ± 10.4		56.9 ± 10.6		0.424	55.3 ± 10.4		55.1 ± 11.5		0.925
Sex					0.345					0.615
Female	6	17.1	156	25.7		6	17.1	17	12.1
Male	29	82.9	452	74.3		29	82.9	123	87.9
BMI, kg/m2[1]	23.0 ± 2.7		22.2 ± 3.0		0.152	23.0 ± 2.7		23.1 ± 3.0		0.858
ASA score					0.014					0.944
I	4	11.4	186	30.6		4	11.4	19	13.6
II	28	80.0	401	65.9		28	80.0	109	77.8
III	3	8.6	21	3.5		3	8.6	12	8.6
cT classification					0.037					0.211
T2	10	28.6	100	16.4		10	28.6	22	15.7
T3	15	42.9	207	34.1		15	42.9	69	49.3
T4a	10	28.6	301	49.5		10	28.6	49	35.0
cN classification					0.483					0.541
N0	13	37.1	212	34.8		13	37.1	57	40.7
N1	14	40.0	187	30.6		14	40.0	39	27.9
N2	4	11.4	122	20.0		4	11.4	21	15.0
N3	4	11.4	89	14.6		4	11.4	23	16.4
cTNM stage					0.094					0.137
IB	2	5.7	55	9.0		2	5.7	13	9.3
IIA	7	20.0	106	17.4		7	20.0	18	12.9
IIB	13	37.1	104	17.1		13	37.1	31	22.1
IIIA	7	20.0	137	22.5		7	20.0	22	15.7
IIIB	3	8.6	109	17.9		3	8.6	29	20.7
IIIC	3	8.6	97	16.0		3	8.6	27	19.3
Depth of invasion					0.201					0.617
pT1a	5	14.3	31	5.1		5	14.3	10	7.1
pT1b	4	11.4	52	8.6		4	11.4	24	17.1
pT2	2	5.7	55	9		2	5.7	10	7.1
pT3	16	45.7	283	46.5		16	45.7	57	40.7
pT4a	8	22.9	187	30.8		8	22.9	39	27.9
Metastatic LNs					0.308					0.649
N0	16	45.7	194	31.9		16	45.7	54	38.6
N1	6	17.1	174	28.7		6	17.1	20	14.3
N2	6	17.1	120	19.7		6	17.1	23	16.4
N3	7	20.0	120	19.7		7	20.0	43	30.7
pTNM stage					0.038					0.102
IA	7	20.0	44	7.2		7	20.0	29	20.7
IB	3	8.6	45	7.4		3	8.6	8	5.7
IIA	6	17.1	91	15.0		6	17.1	23	16.4
IIB	6	17.1	93	15.3		6	17.1	16	11.4
IIIA	6	17.1	122	20.1		6	17.1	8	5.7
IIIB	2	5.7	149	24.5		2	5.7	31	22.1
IIIC	5	14.3	64	10.5		5	14.3	25	17.9
Charlson score					0.467					0.132
0	25	71.5	439	72.2		25	71.5	90	64.3
1	6	17.1	129	21.2		6	17.1	43	30.7
≥2	4	11.4	40	6.6		4	11.4	7	5.0
Primary site					0.458					0.335
Upper	21	60.0	402	66.1		21	60.0	96	68.6
Middle	14	40.0	206	33.9		14	40.0	44	31.4

¹Values are expressed as the mean ± SD. RSPSHL: Robotic spleen-preserving splenic hilar lymphadenectomy; LSPSHL: Laparoscopic spleen-preserving splenic hilar lymphadenectomy; BMI: Body mass index; ASA: American Society of Anesthesiologists; LN: Lymph node.

Table 2 Operative outcomes after propensity score matching

Variable	RSPSHL (n = 35)	%	LSPSHL (n = 140)	%	P-value
Total operative time, min1	221.3 ± 40.3		189.1 ± 43.8		<0.001
Docking time, min2	30 (26-34)		-
OR time, min1	186.0 ± 35.3		189.1 ± 43.8		0.698
EBL, mL1	13.7 ± 4.3		62.4 ± 29.3		<0.001
SHDT, min1	20.4 ± 4.5		24.1 ± 8.9		0.018
First step, min1	8.4 ± 3.5		8.7 ± 4.0		0.685
Second step, min1	6.7 ± 2.6		9.8 ± 5.6		0.002
Third step, min1	5.2 ± 2.1		5.6 ± 3.0		0.458
SHBL, mL1	2.2 ± 1.9		10.0 ± 4.5		<0.001
No. of SGVs1	3.5 ± 1.2		3.6 ± 1.1		0.637
No. of PGAs (yes)	22	62.9	81	57.9	0.591
No. of SUPAs (yes)	4	11.4	20	14.3	0.870
No. of SLPAs (yes)	1	2.9	7	5	0.928
Terminal branches of SpA					0.754
Concentrated type	23	65.7	88	62.9
Distributed type	12	34.3	52	37.1
Splenic injury	3	8.6	19	13.6	0.608
Vascular injury	7	20	17	12.1	0.350
No.10 metastatic LN	4	11.4	15	10.7	0.855
No.10 retrieved LN1	3.1 ± 1.4		3.3 ± 2.5		0.650
Total retrieved LNs1	37.8 ± 13.1		40.6 ± 13.6		0.274

¹Values are the mean ± SD.

²Values are medians (IQR). Operative total time = Docking time + operation time. RSPSHL: Robotic spleen-preserving splenic hilar lymphadenectomy; LSPSHL: Laparoscopic spleen-preserving splenic hilar lymphadenectomy; OR time: Operation time; EBL: Estimated blood loss; SHDT: Splenic hilar dissection time; SHBL: Splenic hilar blood loss; SGV: Short gastric vessel; PGA: Post-gastric artery; SUPA: Splenic upper pole artery; SLPA: Splenic lower pole artery; SpA: Splenic artery.

Table 3 Noncompliance rate of nodal dissection between robotic spleen-preserving splenic hilar lymphadenectomy and laparoscopic spleen-preserving splenic hilar lymphadenectomy

Variable	RSPSHL		LSPSHL		P-value
	Compliant	Noncompliant	Compliant	Noncompli-ant
cT classification
cT2	3	7	6	16	0.791
cT3	6	9	31	39	0.761
cT4	4	6	19	29	0.741
cN classification
cN0	4	9	22	36	0.868
cN1	6	8	15	23	0.825
cN2	2	2	11	10	0.647
cN3	1	3	8	15	0.848
cTNM stage
I	1	1	5	8	1.000
II	9	16	18	31	0.950
III	3	5	33	45	0.909
BMI, kg/m2
< 25	11	14	38	68	0.449
≥ 25	2	8	18	16	0.139
Total	13	22	56	84	0.757

RSPSHL: Robotic spleen-preserving splenic hilar lymphadenectomy; LSPSHL: Laparoscopic spleen-preserving splenic hilar lymphadenectomy; BMI: Body mass index.

Table 4 Short-term operative outcomes and postoperative complications according to the Clavien–Dindo classification

Variable	RSPSHL (n = 35)	%	LSPSHL (n = 140)	%	P-value
Time to ambulation, d1	2.4 ± 0.9		2.1 ± 1.0		0.107
Flatus passage, d1	3.2 ± 0.9		3.5 ± 1.3		0.199
Liquid diet, d1	4.8 ± 1.1		5.4 ± 1.7		0.049
Soft diet, d1	7.0 ± 2.4		7.5 ± 1.5		0.125
Drain removal, d1	9.2 ± 2.1		9.6 ± 2.0		0.296
Nasojejunal tube removal, d1	3.9 ± 1.6		4.8 ± 2.5		0.044
LOS, d1	14.7 ± 13.4		14.4 ± 11.5		0.894
Overall complications	5	14.3	25	17.9	0.616
Grade I–II	3	8.6	17	12.1	0.632
Anastomotic fistula	2	5.7	3	2.1
Digestive hemorrhage	-		1	0.7
Lymphatic fistula	-		6	4.3
Intestinal obstruction	-		1	0.7
Intraperitoneal infection	1	2.9	4	2.9
Wound infection	-		1	0.7
Fat liquefaction	-		1	0.7
Grade III-IV	2	5.7	8	5.7	1
Anastomotic fistula	-		1	0.7
Digestive hemorrhage	1	2.9	3	2.1
Lymphatic fistula	-		2	1.4
Intestinal obstruction	-		1	0.7
Intraperitoneal infection	1	2.9	1	0.7
30-day mortality	0		0
In-hospital mortality	0		0

¹Values are the mean ± SD. The most severe complication was noted in the cases in which more than one complication occurred in a patient. RSPSHL: Robotic spleen-preserving splenic hilar lymphadenectomy; LSPSHL: Laparoscopic spleen-preserving splenic hilar lymphadenectomy; LOS: Length of stay.

Table 5 Time difference between the first and second steps among robotic spleen-preserving splenic hilar lymphadenectomy patients

Variable	First step time (min)1	Second step time (min)1	P-value
Total RSPSHL (n = 35)	8.4 ± 3.5	6.7 ± 2.6	0.024
EG (n = 20)	10.0 ± 3.4	7.5 ± 2.6	0.013
LG (n = 15)	6.3 ± 2.3	5.8 ± 2.2	0.548

¹Values are the mean ± SD. EG: Early group; LG: Late group; RSPSHL: Robotic spleen-preserving splenic hilar lymphadenectomy.