Non-robotic minimally invasive gastrectomy as an independent risk factor for postoperative intra-abdominal infectious complications: A single-center, retrospective and propensity score-matched analysis

Table 1 Patient backgrounds and surgical outcomes following minimally invasive gastrectomy at our institution, n = 1401

Clinicopathological characteristics		Surgical outcomes
Age (yr)	69 (24–93)	No. of operators (certified surgeon)	33 (19)
Gender (M:F)	973:428	Qualified:non-qualified surgeons	925:476
Body mass index (kg/m2)	22.3 (1 4.3–37.3)	Procedure (RG:LG)	359:1042
ASA grade (1:2:3)	500:733:168	Type of resection (DG:PG:TG)	993:89:319
History of laparotomy, n (%)	263 (18.8)	Extent of lymphadenectomy (D1+:D2)	767:634
Tumor size (mm)	30 (0–180)	Splenectomy, n (%)	40 (2.9)
cT1 (1:2:3:4a)	751:264:224:162	Total operative time (min)	348 (147–942)
cN1 (−:+)	1093:308	Estimated blood loss (mL)	30 (0–2150)
cStage1 (I:IIA:IIB:III)	939:76:154:232	No. of dissected LNs	35 (6–114)
pT1 (1:2:3:4a)	797:164:178:262	Conversion to open procedure, n (%)	1 (0.1)
pN1 (0:1:2:3)	949:174:137:141	Reoperation rate, n (%)	15 (1.1)
pStage1 (I:II:III)	856:280:265	In-hospital mortality, n (%)	4 (0.3)
No. of metastatic LNs	0 (0–63)	Morbidity, n (%)	105 (7.5)
Use of preoperative chemotherapy, n (%)	120 (8.6)	Hospital stay following surgery (d)	13 (2–195)

¹Japanese Classification of Gastric Carcinoma, 15^th edition. Data are presented as median with range unless otherwise specified. ASA: American Society of Anesthesiologist; LNs: Lymph nodes; RG: Robotic gastrectomy; LG: Laparoscopic gastrectomy; DG: Distal gastrectomy; PG: Proximal gastrectomy; TG: Total gastrectomy.

Table 2 Risk factors for morbidity after minimally invasive gastrectomy, n = 1401

Factors	Univariate analysis, OR (95%CI)	P value	Multivariate analysis, OR (95%CI)	P value
Non-robotic minimally invasive surgery	2.438 (1.381–4.304)	0.002	2.591 (1.418–4.717)	0.002
Age ≥ 70 yr	1.020 (0.706–1.474)	0.920
Male	2.277 (1.372–3.779)	0.001	1.969 (1.142–3.390)	0.015
Body mass index ≥ 23 kg/m2	1.138 (0.763–1.698)	0.538
ASA score 2 or higher	1.069 (0.703–1.625)	0.832
cT21 or higher	1.296 (0.870–1.930)	0.222
cN1 positive	1.183 (0.745–1.879)	0.540
cStage II1 or higher	1.649 (1.102–2.467)	0.017	1.247 (0.809–1.922)	0.318
Proximal or total gastrectomy	1.847 (1.230–2.772)	0.004	1.208 (0.753–1.937)	0.433
D2 lymph node dissection	1.204 (0.809–1.792)	0.415
Splenectomy	2.734 (1.179–6.339)	0.026	1.360 (0.542–3.408)	0.512
History of laparotomy	1.083 (0.658–1.783)	0.795
Operative time ≥ 360 min	2.449 (1.613–3.718)	< 0.001	1.800 (1.098–2.952)	0.020
Estimated blood loss ≥ 50 mL	2.039 (1.367–3.042)	< 0.001	1.368 (0.873–2.143)	0.209
Tumor size ≥ 30 mm	1.119 (0.703–1.782)	0.721
pT21 or higher	1.378 (0.926–2.052)	0.125
pN1 positive	1.155 (0.761–1.753)	0.516
pStage II 1 or higher	1.471 (0.987–2.192)	0.061
Use of neoadjuvant chemotherapy	1.274 (0.662–2.452)	0.467
Non-qualified surgeons	1.148 (0.785–1.679)	0.521

¹Japanese Classification of Gastric Carcinoma, 15^th edition. The χ² test was used for univariate analysis. Multivariate logistic regression was used for multivariate analyses of factors having a P value of < 0.05 during univariate analysis. ASA: American Society of Anesthesiologist; OR: Odds ratio; CI: Confidence interval.

Table 3 Patient characteristics and clinicopathological features by each type of procedure

	Entire cohort (n = 1401)		P value	SD	Propensity-score matched cohort (n = 708)		P value	SD
	RG (n = 359)	LG (n = 1042)			RG (n = 354)	LG (n = 354)
Age (yr)	67 (30–89)	70 (24–93)	< 0.001	0.24	67 (30–89)	66 (24–90)	0.315	0.10
Gender (M:F)	233:126	740:302	0.033	0.12	230:124	230:124	1.000	0
Body mass index (kg/m2)	22.9 (14.3–32.0)	22.2 (14.5–37.3)	0.021	0.12	22.8 (14.3–32.0)	22.4 (14.9–37.3)	0.752	0.03
ASA grade (1:2:3)	160:168:31	340:565:137	< 0.001	0.25	155:168:31	149:174:31	0.905	0.03
History of laparotomy, n (%)	66 (18.4)	197 (18.9)	0.876	0.01	65 (18.4)	59 (16.7)	0.621	0.04
Tumor size (mm)	30 (0–170)	30 (0–180)	0.013	0.14	30 (0–170)	30 (0–180)	0.208	0.09
cT1 (1:2:3:4a)	198:75:56:30	553:189:168:132	0.131	0.04	195:74:55:30	204:70:48:32	0.834	0.05
cN1 (−:+)	287:72	806:236	0.337	0.06	284:70	289:65	0.702	0.04
cStage1 (I:II:III)	249:62:48	690:168:184	0.183	0.07	246:61:47	252:59:43	0.962	0.04
pT1 (1:2:3:4a)	210:36:46:67	587:128:132:195	0.711	0.05	208:36:46:64	213:36:39:66	0.882	0.03
pN1 (0:1:2:3)	249:47:24:39	700:127:113:102	0.145	0.05	246:46:24:38	244:48:18:44	0.72	0.01
pStage1 (I:II:III)	221:80:58	635:200:207	0.200	0.01	219:78:57	224:71:59	0.823	0.03
No. of metastatic LNs	0 (0–43)	0 (0–63)	0.385	0.03	0 (0–43)	0 (0–37)	0.819	0.02
Use of preoperative chemotherapy, n (%)	19 (5.3)	101 (9.7)	0.011	0.17	19 (5.4)	18 (5.1)	> 0.999	0.01
Type of resection (DG:PG:TG)	250:42:67	743:47:252	< 0.001	0.13	248:39:67	252:33:69	0.778	0.01
Extent of lymphadenectomy (D1+:D2)	178:181	589:453	0.023	0.14	175:179	175:179	> 0.999	0
Splenectomy, n (%)	6 (1.7)	34 (3.3)	0.142	0.11	6 (1.7)	7 (2.0)	> 0.999	0.02

¹Japanese Classification of Gastric Carcinoma, 15^th edition. Data are shown as median with range unless otherwise specified. The χ² test was used for between-group comparison of gender, American Society of Anesthesiologist grade, history of laparotomy, cT, cN, cStage, pT, pN, pStage, use of preoperative chemotherapy, type of resection, extent of lymphadenectomy, and splenectomy. The Mann–Whitney U test was applied for between-group comparison of age, body mass index, tumor size, and number of metastatic lymph nodes. RG: Robotic gastrectomy; LG: Laparoscopic gastrectomy; SD: Standardized difference; ASA: American Society of Anesthesiologist; LNs: Lymph nodes.

Table 4 Surgical outcomes and short-term postoperative courses

	Entire cohort (n = 1401)		P value	Propensity-score matched cohort (n = 708)		P value
	RG (n = 359)	LG (n = 1042)		RG (n = 354)	LG (n = 354)
No. of operators (qualified surgeon)	8 (8)	33 (14)	NA	8 (8)	33 (14)	NA
Qualified:non-qualified surgeons	359:0	572:475	< 0.001	354:0	186:149	< 0.001
Total operative time (min)	360 (174–942)	342 (147–937)	< 0.001	360 (174–942)	347 (149–937)	0.001
Console time (min)	306 (136–860)	NA	NA	307 (136–860)	NA	NA
Estimated blood loss (mL)	36 (0–935)	29 (0–2150)	0.007	37 (0–935)	28 (0–2150)	0.005
No. of dissected LNs	37 (7–100)	35 (6–114)	0.058	37 (7–100)	36 (6–108)	0.807
Conversion to open procedure, n (%)	0 (0)	1 (0.1)	> 0.999	0	0	> 0.999
Reoperation rate, n (%)	4 (1.1)	11 (1.1)	> 0.999	4 (1.1)	6 (1.7)	0.750
Hospital stay following surgery (d)	12 (2–195)	13 (3–177)	< 0.001	12 (2–195)	13 (3–131)	0.001
In-hospital mortality, n (%)	2 (0.6)	2 (0.3)	0.578	2 (0.6)	1 (0.3)	> 0.999

Data are presented as median with range unless otherwise stated. The χ² test was used for between group comparison of comparison of proportion of qualified and non-qualified surgeons, splenectomy, conversion to open procedure, reoperation rate, and in-hospital mortality. The Mann–Whitney U test was applied for between-group comparison of total operative time, estimated blood loss, number of dissected lymph nodes, and hospital stay following surgery. RG: Robotic gastrectomy; LG: Laparoscopic gastrectomy; LNs: Lymph nodes.

Table 5 Postoperative complications with a Clavien–Dindo grade of IIIa or higher, n (%)

	Entire cohort (n = 1401)		P value	Propensity-score matched cohort (n = 708)		P value
	RG (n = 359)	LG (n = 1042)		RG (n = 354)	LG (n = 354)
Morbidity	13 (3.6)	92 (8.8)	0.002	13 (3.7)	27 (7.6)	0.033
Intra-abdominal infection	9 (2.5)	66 (6.3)	0.005	9 (2.5)	21 (5.9)	0.038
Anastomotic leakage	6 (1.7)	22 (2.1)	0.670	6 (1.7)	7 (2.0)	> 0.999
Pancreatic fistula	3 (0.8)	28 (2.7)	0.058	3 (0.8)	9 (2.5)	0.143
Intraperitoneal abscess	0 (0)	16 (1.5)	0.017	0 (0)	5 (1.4)	0.062
Other local complications	3 (0.8)	14 (1.3)	0.632	2 (0.6)	4 (1.1)	0.682
Intra-abdominal bleeding	2 (0.6)	4 (0.4)	> 0.999	1 (0.3)	2 (0.6)	> 0.999
Bowel obstruction	0 (0)	7 (0.6)	0.150	0 (0)	0 (0)	> 0.999
Anastomotic stenosis	1 (0.3)	3 (0.3)	> 0.999	1 (0.3)	2 (0.6)	> 0.999
Systemic complications	1 (0.3)	17 (1.6)	0.091	1 (0.3)	4 (1.1)	0.369
Pneumonia	0 (0)	9 (0.9)	0.256	0 (0)	2 (0.6)	0.499
Pulmonary embolism	1 (0.3)	2 (0.2)	0.726	1 (0.3)	0 (0)	> 0.999
Renal dysfunction	0 (0)	1 (0.1)	0.573	0 (0)	0 (0)	> 0.999
Cardiovascular disease	0 (0)	5 (0.5)	0.337	0 (0)	2 (0.6)	0.499

The χ² test was used for between-group comparison. RG: Robotic gastrectomy; LG: Laparoscopic gastrectomy.

Table 6 Risk factors for intra-abdominal infectious complications (propensity score-matched cohort, n = 708)

Factors	Univariate analysis, OR (95%CI)	P value	Multivariate analysis, OR (95%CI)	P value
Non-robotic minimally invasive surgery	2.333 (1.084–5.024)	0.038	2.463 (1.070–5.682)	0.034
Age ≥ 70 yr	1.141 (0.546–2.388)	0.849
Male	4.852 (1.487–15.834)	0.003	3.937 (1.157–13.333)	0.028
Body mass index ≥ 23 kg/m2	1.064 (0.511–2.214)	> 0.999
ASA score 2 or higher	1.135 (0.538–2.393)	0.851
cStage II1 or more	1.394 (0.651–2.982)	0.416
Proximal or total gastrectomy	2.513 (1.205–5.240)	0.014	1.694 (0.722–3.974)	0.226
D2 dissection	1.023 (0.508–2.061)	> 0.999
Splenectomy	1.579 (0.467–5.339)	0.668
Operative time ≥ 360 min	4.863 (1.963–12.048)	< 0.001	2.779 (1.003–7.701)	0.049
Estimated blood loss ≥ 50 mL	3.596 (1.682–7.687)	0.001	2.204 (0.967–5.023)	0.060
Tumor size ≥ 30 mm	1.057 (0.508–2.201)	> 0.999
pStage II1 or more	1.120 (0.531–2.363)	0.848
Use of neoadjuvant chemotherapy	1.599 (0.224–11.419)	0.729
Non-qualified surgeons	2.047 (1.018–4.118)	0.045	1.852 (0.810–4.237)	0.145

¹Japanese Classification of Gastric Carcinoma, 15^th edition. The χ² test was used for univariate analysis. Multivariate logistic regression was used for multivariate analyses of factors having a P value of < 0.05 during univariate analysis. ASA: American Society of Anesthesiologist; OR: Odds ratio; CI: Confidence interval.