Table 1 Cohort overview and comparison of recurrence and residual disease groups

Technique of the previous surgery

< 0.001

 MTS

40 (61.5)

36 (76.6)

4 (22.2)

 ETS

25 (38.5)

11 (23.4)

14 (77.8)

Tumor size

 Microadenoma

41 (63.1)

30 (63.8)

11 (61.1)

0.839

 Macroadenoma

24 (36.9)

17 (36.2)

7 (38.9)

Multifocality

 Unifocal

50 (76.9)

37 (78.7)

13 (72.2)

0.743

 Bifocal

15 (23.1)

10 (21.3)

5 (27.8)

Relation to cavernous sinus

 Extension

21 (32.3)

15 (31.9)

6 (33.3)

0.589

 Invasion

10 (15.4)

6 (12.8)

4 (22.2)

 No relationship

34 (52.3)

26 (55.3)

8 (44.4)

Hardy-Wilson Classification

0.339

 Grade

  I

38 (58.5)

25 (59.5)

8 (57.1)

  II

16 (24.6)

8 (19)

5 (5)

  III

6 (9.2)

6 (14.3)

1 (7.1)

  IV

5 (7.7)

3 (7.1)

0 (0)

 Stage

0.443

  A

30 (46.2)

19 (45.2)

7 (50)

  B

7 (10.8)

4 (9.5)

3 (21.4)

  C

2 (3.1)

2 (4.8)

0 (0)

  D

1 (1.5)

0 (0)

0 (0)

  E

25 (38.5)

17 (40.5)

4 (28.6)

Laboratory values

 Preoperative serum ACTH (pg/mL)

182.71 ± 577.08

60.5 [37.15–104.5]

220.7 ± 675.73

83.5 ± 61.7

0.395

 Preoperative serum Cortisol (µg/dL)

18.75 ± 11.16

17 [12-24.65]

19.18 ± 12.11

17.64 ± 8.39

0.621

 Postoperative serum ACTH (pg/mL)

43.29 ± 50.2

25.5 [15.8–53.7]

43.07 ± 45.42

43.94 ± 63.96

0.953

 Postoperative serum Cortisol (µg/dL)

13.41 ± 13.85

6.45 [1.77–21.01]

14.62 ± 14.52

10.25 ± 11.7

0.259

POD 1 Cortisol level

0.700

 >5 µg/dL

35 (53.8)

26 (55.3)

9 (50)

 ≤5 µg/dL

30 (46.2)

21 (44.7)

9 (50)

Tumor pathology

0.198

 ACTH + adenoma

55 (85)

40 (85.1)

15 (83.3)

 Crooke degeneration

2 (3)

1 (2.1)

1 (5.6)

 Pituitary hyperplasia

2 (3)

1 (2.1)

1 (5.6)

 Normal pituitary tissue

6 (9)

5 (10.6)

1 (5.6)

Result of reoperation

0.740

 Remission

51 (78.5)

36 (76.6)

15 (83.3)

 Residual disease

14 (21.5)

11 (23.4)

3 (16.7)