Patient selection and operative strategies for laparoscopic intersphincteric resection without diverting stoma

Table 1 Clinical and surgical characteristics before and after matching

Variables	Before PSM		P value	After PSM		P value
	DS (n = 421)	SF (n = 84)		DS (n = 78)	SF (n = 78)
Gender			0.042			0.521
Male	273 (64.8)	44 (52.4)		34 (43.6)	39 (50.0)
Female	148 (35.2)	40 (47.6)		44 (56.4)	39 (50.0)
Age, median (range) years	60.0 (20.0, 84.0)	64.0 (23.0, 84.0)	0.003	64.0 (31.0, 82.0)	64.0 (33.0, 84.0)	1
< 60	204 (48.4)	25 (29.8)		25 (32.1)	25 (32.1)
≥ 60	217 (51.6)	59 (70.2)		53 (67.9)	53 (67.9)
BMI, median (range) kg/m2	23.7 (14.5, 32.9)	23.8 (17.8, 34.4)	1	23.9 (17.1, 29.3)	23.7 (17.8, 34.4)	1
< 25	270 (64.1)	54 (64.3)		51 (65.4)	52 (66.7)
≥ 25	151 (35.9)	30 (35.7)		27 (34.6)	26 (33.3)
ASA score			0.005			0.744
I-II	408 (96.9)	75 (89.3)		74 (94.9)	72 (92.3)
III	13 (3.1)	9 (10.7)		4 (5.1)	6 (7.7)
Diabetes			1			0.811
Yes	55 (13.1)	11 (13.1)		9 (11.5)	11 (14.1)
No	366 (86.9)	73 (86.9)		69 (88.5)	67 (85.9)
Tumor size, median (range) mm	35.0 (10.0, 120.0)	35.0 (15.0, 80.0)	0.628	35.0 (20.0, 90.0)	35.0 (15.0, 80.0)	0.958
> 35	209 (49.6)	41 (48.8)		32 (41.0)	36 (46.2)
≤ 35	212 (50.4)	43 (51.2)		46 (59.0)	42 (53.8)
Differentiation status			0.216			0.277
Poor	65 (15.4)	8 (9.5)		10 (12.8)	5 (6.4)
Well-moderate	356 (84.6)	76 (90.5)		68 (87.2)	73 (93.6)
Tumor type			0.944			1
Ulcer	281 (66.7)	57 (67.9)		57(73.1)	57(73.1)
Protrusion	140 (33.3)	27 (32.1)		31(26.9)	31(26.9)
pT stage			0.362			0.255
0-2	181 (43.0)	31 (36.9)		36 (46.2)	28 (35.9)
3	240 (57.0)	53 (63.1)		42 (53.8)	50 (64.1)
pN stage			0.782			0.104
N+	150 (35.6)	28 (33.3)		16 (20.5)	26 (33.3)
N0	271 (64.4)	56 (66.7)		62 (79.5)	52 (66.7)
M stage			1			1
M1	8 (1.9)	1 (1.2)		1 (1.3)	1 (1.3)
M0	413 (98.1)	83 (98.8)		77 (98.7)	77 (98.7)
pTNM stage			0.659			0.104
I-II	154 (36.6)	28 (33.3)		16 (20.5)	26 (33.3)
III-IV	267 (63.4)	56 (66.7)		62 (79.5)	52 (66.7)
nCRT			0.009			1
Yes	62 (14.7)	3 (3.6)		4 (5.1)	3 (3.8)
No	359 (85.3)	81 (96.4)		74 (94.9)	75 (96.2)
Tumor height from anal verge, median (range) cm	4.0 (3.5-4.0)	4.5 (4.0-5.0)	< 0.001	4.0 (4.0-4.5)	4.0 (4.0-4.5)	0.412
≤ 4.0	343 (81.5)	41 (48.8)		48 (61.5)	39 (50.0)
> 4.0	68 (18.5)	43 (51.2)		30 (38.5)	39 (50.0)
Anastomotic height from anal verge, median (range) cm	2.00 (0.50, 4.00)	2.50 (1.00, 4.00)	< 0.001	2.00 (1.00, 4.00)	2.50 (1.00, 4.00)	1
≤ 3.0	406 (96.4)	73 (86.9)		72 (92.3)	72 (92.3)
> 3.0	15 (3.6)	11 (13.1)		6 (7.7)	6 (7.7)
LCA retention			< 0.001			1
Yes	205 (48.7)	61 (72.6)		54 (69.2)	55 (70.5)
No	216 (51.3)	23 (27,4)		24 (30.8)	23 (29.5)
Lateral lymph node dissection			0.260			0.247
Yes	51 (12.1)	6 (7.2)		9 (11.5)	4 (5.1)
No	370 (87.9)	78 (92.8)		69 (88.5)	74 (94.9)
Hb (g/L)			0.911			0.802
≥ 120	366 (86.9)	74 (88.1)		70 (89.7)	68 (87.2)
< 120	55 (13.1)	10 (11.9)		8 (10.3)	10 (12.8)
ALB (g/L)			0.328			0.342
≥ 35.0	334 (79.3)	62 (73.8)		63 (80.8)	57 (73.1)
< 35.0	87 (20.7)	22 (26.2)		15 (19.1)	21 (26.9)
CEA (μg/L)			0.122			0.561
> 5.0	134 (31.8)	19 (22.6)		15 (19.2)	19 (24.4)
≤ 5.0	287 (68.2)	65 (77.4)		63 (80.8)	59 (75.6)

Data are presented as n (%). BMI: Body mass index; ASA: American Society of Anesthesiologists; nCRT: Neoadjuvant chemotherapy; LCA: Left colic artery; Hb: Hemoglobin; ALB: Albumin; PSM: Propensity score matching; DS: Diverting stoma; SF: Stoma-free; CEA: Carcinoembryonic antigen.

Table 2 Perioperative outcomes of patients who underwent laparoscopic intersphincteric resection before and after propensity score matching

Variables	Before PSM		P value	After PSM		P value
	DS (n = 421)	SF (n = 84)		DS (n = 78)	SF (n = 78)
Operative time, median (range) min	172 (90, 335)	171 (85, 485)	0.015	174 (90, 335)	168 (90, 480)	0.109
Blood loss, median (range) mL	50 (20, 800)	50 (5, 500)	0.862	50 (10, 200)	50 (5, 500)	0.611
Conversion to open surgery	0 (0)	0 (0)	-	0 (0)	0 (0)	-
Postoperative complication	58 (13.8)	16 (19.0)	0.212	12 (15.4)	15 (19.2)	0.481
CD grade I-II	43 (10.2)	8 (9.5)	0.516	10 (12.8)	7 (9.0)	0.602
CD grade ≥III	15 (3.6)	8 (9.5)	0.035	2 (2.6)	8 (10.3)	0.050
Anastomotic leakage	32 (7.6)	11 (13.1)	0.099	2 (2.6)	10 (12.8)	0.035
Grade A-B	30 (7.1)	6 (7.1)	0.996	2 (2.6)	5 (6.4)	0.439
Grade C	2 (0.5)	5 (6.0)	< 0.001	0 (0)	5 (6.4)	0.069
Ileus	17 (4.0)	0 (0)	0.123	5 (6.4)	0 (0)	0.069
Hemorrhage postoperation	0 (0)	1 (0)	0.370	0 (0)	1 (1.3)	0.316
Mortality	2 (0.5)	1 (1.2)	0.999	1 (1.3)	1 (1.3)	0.669
Reoperation	6 (1.4)	5 (6.0)	0.074	0 (0)	5 (6.4)	0.069
Postoperative hospital stay (day)	9 (4-51)	11 (4-37)	0.070	10 (5-30)	12 (6-37)	0.275
Anastomosis recurrence	8 (1.9)	0 (0)	0.427	2 (2.6)	0 (0)	0.477
Rectovaginal fistula	4 (1.0)	1 (1.2)	0.363	0 (0)	1 (0)	0.998
Anastomotic stricture	21 (5.0)	0 (0)	0.206	2 (2.6)	0 (0)	0.477
Completion rate of postoperative chemotherapy	191/220 (86.8)	23/39 (59.0)	< 0.001	22/25 (88.0)	20/24 (88.9)	0.933
Permanent stoma	47 (11.2%)	2 (2.3%)	< 0.001	5 (6.4)	2 (2.6)	0.521

Data are presented as n (%). CD: Clavien-Dindo; PSM: Propensity score matching; DS: Diverting stoma; SF: Stoma-free.

Table 3 The univariate analysis and multivariate analysis of anastomotic leakage in baseline cohorts and non-diverting stoma cohorts

Variable	Baseline cohort (n = 505)				SF cohort (n = 84)
	Univariate analysis		Multivariate analysis		Univariate analysis		Multivariate analysis
	Odds ratio (95%CI)	P value	Odds ratio (95%CI)	P value	Odds ratio (95%CI)	P value	Odds ratio (95%CI)	P value
Sex (male vs female)	2.883 (1.310-6.343)	0.009	2.644 (1.161-6.020)	0.021	2.741 (0.673-11.159)	0.159	2.648 (0.606-11.575)	0.196
Age (≥ 60 years vs < 60 years)	0.738 (0.397-1.370)	0.336			0.707 (0.187-2.669)	0.609
BMI (≥ 25 kg/m2 vs < 25 kg/m2)	1.899 (1.020-3.536)	0.043	1.716 (0.884-3.330)	0.111	2.450 (0.679-8.841)	0.171	2.678 (0.672-10.678)	0.163
Diabetes (yes vs no)	1.544 (0.684-3.485)	0.296			1.580 (0.293-8.509)	0.594
nCRT (yes vs no)	4.805 (2.429-9.502)	< 0.001	6.024 (2.830-12.822)	< 0.001	-	-
LCA retention (yes vs no)	0.068 (0.341-0.102)	0.105	0.417 (0.209-0.830)	0.013	0.393 (0.028-0.891)	0.039	0.312 (0.021-0.802)	0.027
Diverting stoma (yes vs no)	0.564 (0.273-1.167)	0.123	0.204 (0.087-0.481)	< 0.001
Maximal tumor size (> 35 mm vs ≤ 35 mm)	0.925 (0.498-1.718)	0.805			1.167 (0.311-4.376)	0.819
TNM stage (III–IV vs I-II)	1.254 (0.667-2.355)	0.482			--	--
Height of tumor from the anal verge (≤ 4 cm vs > 4 cm)	2.563 (0.986-6.658)	0.053	4.160 (1.488-11.634)	0.007	1.587 (0.183-13.780)	0.675
Vascular invasion (yes vs no)	1.433 (0.697-2.947)	0.328			1.253 (0.238-6.594)	0.790
Nerve invasion (yes vs no)	1.563 (0.740-3.303)	0.242			2.741 (0.673-11.159)	0.159	2.648 (0.606-11.575)	0.196

BMI: Body mass index; nCRT: Neoadjuvant chemotherapy; LCA: Left colic artery; SF: Stoma-free; CI: Confidence interval.

Table 4 Clinical characteristics and outcomes between the high-risk and low-risk cohorts of anastomotic leakage patients

Variables	High-risk cohort of AL (n = 408)	Low-risk cohort of AL (n = 97)	P value
Tumor size, median (range) mm			0.212
> 35	208 (60.0)	42 (43.3)
≤ 35	200 (40.0)	55 (56.7)
Differentiation status			0.625
Poor	61 (15.0)	12 (12.4)
Well-moderate	347 (85.0)	85 (87.6)
pT stage			0.014
0-2	160 (39.2)	52 (53.6)
3	248 (60.8)	45 (46.4)
pN stage			0.267
N+	149 (36.5)	29 (29.9)
N0	259 (63.5)	68 (70.1)
M stage			0.140
M1	9 (2.2)	0 (0)
M0	399 (97.8)	97 (100)
pTNM stage			0.047
I-II	252 (61.8)	71 (73.2)
III-IV	156 (38.2)	26 (26.8)
Tumor height from anal verge, median (range) cm			0.530
≤ 4.0	309 (75.7)	77 (79.4)
> 4.0	99 (24.3)	20 (20.6)
Operative time, median (range) min	164 (130-195)	175 (139-218)	0.006
Blood loss, median (range) mL	50 (20-50)	50 (20-100)	0.003
Conversion to open surgery	0 (0)	0 (0)	1
Postoperative complication	67 (16.4)	7 (7.2)	0.021
CD grade I-II	46 (11.3)	5 (5.2)	0.072
CD grade ≥ III	21 (5.1)	2 (2.1)	0.299
AL	42 (10.3)	2 (2.1)	0.010
Grade A-B	35 (8.6)	2 (2.1)	0.027
Grade C	7 (1.7)	0 (0)	0.415
Mortality	3 (0.7)	0 (0)	0.397
Reoperation	10 (2.5)	1 (1.0)	0.635
Postoperative hospital stay (day)	9 (4-50)	10 (4-47)	0.081
Anastomosis recurrence	7 (1.7)	1 (1.0)	0.974

Data presented as n (%). AL: Anastomotic leakage; CD: Clavien-Dindo.