Construction of a nomogram model to predict technical difficulty in performing laparoscopic sphincter-preserving radical resection for rectal cancer

Table 7 Univariate analysis of risk factors associated with surgical difficulty in 162 cases of laparoscopic radical sphincter-preserving surgery for rectal cancer

Factors	Entire group	Low difficulty group	High difficulty group	P value
Age (yr)	65 (59, 72)	65 (58, 73)	65 (62, 71)	0.992
Gender				0.15712
Male	105 (64.81)	88 (62.41)	17 (80.95)
Female	57 (35.19)	53 (37.59)	4 (19.05)
BMI (kg/m²)	22.75 ± 3.25	22.7 ± 3.2	23.04 ± 3.64	0.6965
Underlying comorbidities	72 (44.44)	65 (46.1)	7 (33.33)	0.38812
ASA grade				0.83321
I	18 (11.11)	15 (10.64)	3 (14.29)
II	137 (84.57)	121 (85.82)	16 (76.19)
III	7 (4.32)	5 (3.55)	2 (9.52)
History of previous abdominal surgery	15 (9.26)	15 (10.64)	0	0.22172
Preoperative total Protein (g/L)	65.45 (62.4, 68.83)	65.1 (62.4, 68.3)	66.4 (62.5, 70.2)	0.32101
Preoperative albumin (g/L)	38.64 ± 3.32	38.54 ± 3.25	39.3 ± 3.79	0.3892
Preoperative albumin to globulin ratio	1.4 (1.3, 1.6)	1.4 (1.3, 1.6)	1.4 (1.3, 1.6)	0.70931
Preoperative Hemoglobin (g/L)	134.5 (119, 143.75)	134 (119, 143)	141 (126, 151)	0.09621
PNI	47.23 ± 5.02	47.02 ± 4.81	48.63 ± 6.2	0.2637
Preoperative CEA (ug/L)	2.9 (1.9, 5.18)	2.9 (1.8, 5.2)	2.9 (1.9, 4.6)	0.22571
Preoperative CA199 (kU/L)	8.55 (5.18, 17.98)	8.3 (5, 18)	10.8 (6.9, 17.9)	0.56631
Tumor height (cm)	8 (6.25, 10)	8 (7, 10)	7 (5, 8)	0.00241
Tumor maximum diameter (cm)	3.8 (3, 4.88)	3.8 (3, 4.5)	3 (2.8, 5)	0.55071
Surgical approach				6.775e-41
L-AR	20 (12.35)	19 (13.48)	1 (4.76)
L-LAR	135 (83.33)	120 (85.11)	15 (71.43)
L-ISR	7 (4.32)	2 (1.42)	5 (23.81)
Intraoperative preventive ostomy	39 (20.07)	26 (18.44)	13 (61.90)	4.644e-052
Intraoperative stapler cartridge count	2 (1, 2)	2 (1, 2)	1 (1, 2)	0.09531
Intraoperative stapler cartridge length (mm)	90 (60, 90)	90 (60, 90)	60 (45, 90)	0.09691
Anterior-posterior diameter of pelvic inlet (mm)	115.23 ± 11.79	115.53 ± 11.85	113.23 ± 11.49	0.4025
Transverse diameter of pelvic inlet (mm)	123.52 ± 8.14	123.98 ± 7.79	120.42 ± 9.83	0.126
Anterior-posterior diameter of mid-pelvis (mm)	111.83 (106.36, 117.74)	112.16 (106.74, 118.12)	110.69 (103.69, 115.17)	0.42211
Anterior-posterior diameter of pelvic outlet (mm)	88.97 (82.35, 96.86)	89.18 (82.52, 96.92)	86.53 (81.69, 94.37)	0.86681
Interischial spine diameter (mm)	96.06 (87.3, 104.27)	96.35 (88.76, 104.58)	90.34 (85.01, 100.56)	0.06211
Interischial tuberosity diameter (mm)	104.3 (96.08, 116.95)	104.09 (96.6, 118.44)	107.77 (95.7, 112.01)	0.61451
Superior-inferior diameter of the pubic symphysis (mm)	42.21 ± 4.75	42.14 ± 4.88	42.71 ± 3.77	0.5341
Sacrococcygeal distance (mm)	123.19 ± 11.95	122.49 ± 12.04	127.91 ± 10.42	0.0378
Superior-inferior diameter of sacrum (mm)	105.77 ± 10.17	105.36 ± 10.18	108.5 ± 9.9	0.1881
Sacrococcygeal curvature height (mm)	39.61 (36.15, 42.71)	39.63 (36.14, 43.43)	38.97 (37.68, 40.96)	0.55961
Sacral curvature height (mm)	20.82 ± 5.87	20.83 ± 6.04	34.61 ± 4.11	0.9529
Superior pubococcygeal diameter (mm)	120.26 ± 9.56	120.01 ± 9.28	121.98 ± 11.35	0.4555
Anterior-posterior sacropubic distance (mm)	119.84 (113.14, 126.49)	120.04 (113.25, 127.11)	119.01 (112.86, 121.95)	0.30551
Anterior-posterior diameter of pelvic inlet/sacrococcygeal distance	0.94 (0.86, 1)	0.94 (0.86, 1.02)	0.87 (0.82, 0.97)	0.01651
Sacrococcygeal-pubic angle (°)	48.05 ± 7.01	47.64 ± 7.21	34.61 ± 4.11	0.0116
Sacropubic angle (°)	33.22 (29.5, 36.66)	32.83 (28.98, 36.56)	34.89 (32.05, 36.79)	0.14131
Rectal area (cm2)	16.67 (12.23, 21.48)	16.64 (12.23, 22.57)	17.07 (10.44, 19.59)	0.47581
Mesorectal fat area (cm2)	39.26 (27.41, 51.62)	38.62 (28.18, 51.35)	46.32 (24.25, 54.02)	0.53641
Visceral fat area (cm2)	215.9 (126.21, 274.02)	213.65 (126.1, 260.2)	240.25 (137.54, 320.74)	0.58341
Subcutaneous fat area (cm2)	258.24 (198.25, 340.77)	264.32 (204.34, 341.38)	240.91 (139.23, 310.51)	0.30911
Waist circumference (cm)	82.37 ± 9.15	82.36 ± 8.92	82.44 ± 10.83	0.9741
Anterior-posterior abdominal diameter (cm)	18.44 (16.38, 20.4)	18.41 (16.48, 20.25)	19.11 (16.2, 20.96)	0.59881
Transverse abdominal diameter (cm)	28.84 ± 2.79	28.83 ± 2.69	28.92 ± 3.48	0.6991

¹The Mann-Whitney U test is employed for single-ordered data, while the chi-square test, continuity correction chi-square test.

²Fisher’s exact test are used for two-way unordered data.

In the case of normal distribution, the data is presented as mean ± SD. For non-normal distribution, median (Q1, Q3) is used. Count and ordinal data are represented as frequency (%). Paired t-test is used for parametric data with equal variances, and nonparametric Mann-Whitney U test is used for non-normally distributed data. P values denoted by “e” are all less than 0.001. BMI: Body mass index; ASA: American Society of Anesthesiologists; CD: Clavien-Dindo; PNI: Prognostic nutritional index; L-AR: Laparoscopic anterior resection; L-LAR: Laparoscopic low or ultralow anterior resection; L-ISR: Laparoscopic intersphincteric resection.