Modified abdominal wall retractor for total laparoscopic esophagojejunostomy in gastric cancer

Table 3 Baseline characteristics of patients treated before and after overcoming the learning curve, mean ± SD

Factor	Pre-learning curve (n = 11)	Post-learning curve (n = 22)	t/χ2	P value
Age (year)	66.64 ± 8.51	60.23 ± 10.50	1.48	0.149
Sex			0.000	1.000
Male	8	16
Female	3	6
BMI (kg/m2)	21.78 ± 1.88	22.60 ± 2.45	-0.966	0.342
ASA score				0.586
I/II	9	20
III	2	2
WBC before surgery (× 109/L)	5.71 ± 1.63	5.23 ± 1.57	0.776	0.444
Hb before surgery (g/L)	117.82 ± 13.17	114.73 ± 15.10	0.577	0.568
ALB before surgery (g/L)	36.00 ± 5.31	34.50 ± 3.70	0.948	0.351
Siewert type				0.375
II	8	19
III	3	3
Tumor diameter (cm)	4.14 ± 1.82	4.87 ± 0.80	-1.622	0.115
Degree of differentiation				1.000
Well/moderate	2	3
Worse	9	19
TNM stage				1.000
I/II	9	18
III	2	4

ALB: Albumin; ASA: American Society of Anesthesiologists; BMI: Body mass index; Hb: Hemoglobin; TNM: Tumor, node, metastasis; WBC: White blood cell.