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Table 6 Relationship between intra-operative visual-evoked potential (VEP) and post-operative visual function

From: Intraoperative monitoring of visual evoked potentials in patients undergoing transsphenoidal surgery for pituitary adenoma: a systematic review

Study (Year) Intra-operative VEP Post-operative
Visual Acuity n (%)
Post-operative
Visual Fields n (%)
Notes
Improved Stable Worsened Improved Stable Worsened
Feng et al. (2019) [18] Improved 0 (0) 1 (100) 0 (0) 0 (0) 1 (100) 0 (0) Sensitivity and specificity of VEP amplitude in detecting changes in visual field outcomes are 75% and 79%, respectively
Stable 27 (87) 4 (13) 30 (97) 1 (3)
Worsened (transient) 1 (17) 2 (33) 3 (50) 2 (33) 3 (50) 1 (17)
Worsened (permanent) 2 (50) 1 (25) 1 (25) 1 (25) 1 (25) 2 (50)
Qiao et al. (2019) [19]         Did not measure post-operative outcomes
Toyama et al. (2018) [20] Improved 3 (100) 0 (0) 0 (0) 1 (33) 2 (66) 0 (0) No significant relationship observed between VEP and visual field outcome
Stable 11 (53) 10 (48) 0 (0) 9 (43) 12 (57) 0 (0)
Worsened (transient) 6 (66) 3 (33) 0 (0) 5 (56) 4 (44) 0 (0)
Worsened (permanent) 3 (50) 3 (50) 0 (0) 1 (17) 5 (83) 0 (0)
Kamio et al. (2014) [7] Improved 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) No statistical analysis performed
Stable 11 (48) 12 (52) 0 (0) 5 (22) 18 (78) 0 (0)
Worsened (transient) 2 (50) 2 (50) 0 (0) 2 (50) 2 (50) 0 (0)
Worsened (permanent) 0 (0) 1 (100) 0 (0) 0 (0) 0 (0) 1 (100)
Houlden et al. (2014) [9]         Did not measure post-operative outcomes
Chung et al (2012) [24] Improved 4 (22) 13 (68) 2 (11) 13 (68) 4 (22) 2 (11) No association found between intraoperative VEP waveforms and post-operative visual acuity or visual fields
Stable 13 (20) 42 (66) 9 (14) 39 (64) 17 (26) 8 (13)
Worsened (transient /permanent) 5 (42) 5 (42) 2 (17) 6 (50) 3 (25) 3 (25)
Chacko et al. (1996) [25] Group A Improved 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) There was statistically significant improvement in post-operative visual field testing between the test group A (with VEP monitoring) and the control group B (without VEP monitoring)
There was no statistical difference in visual acuity between the two groups
Stable 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0)
Worsened (transient) n/a n/a n/a 34 (77) 10 (23) 0 (0)
Worsened (permanent) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0)
   Post-operative Visual Functiona  
Improved n (%) Stable n (%) Worsened n (%)  
Nishimura et al. (2018) [21] Improved 0 (0) 0 (0) 0 (0) “Intraoperative monitoring of VEP predicts postoperative visual function, and a reversible change in VEP indicates that visual function will be preserved”(2)
Stable 62 (50) 62 (50) 0 (0)
Worsened (transient) 8 (31) 18 (69) 0 (0)
Worsened (permanent) 0 (0) 8 (100) 0 (0)
Luo et al.b(2015) [23] Improved 0 (0) 0 (0) 0 (0) Intra-operative VEP has a specificity of 96% and a negative predictive value of 90% in detecting post-operative visual functionPreservation of VEPs predicted preserved visual function
Stable 8 (16) 36 (72) 6 (12)
Worsened (transient) 0 (0) 10 (100) 0 (0)
Worsened (permanent) 0 (0) 2 (2) 0 (0)
Sasaki et al.b (2010) [6] Improved 1 (100) 0 0 (0) “Changes in intraoperative VEP findings, especially in the VEP amplitude, were well correlated with postoperative visual function”(3)
Stable 17 (10) 150 (89) 2 (1)
Worsened (transient) 1 (33) 2 (67) 0
Worsened (permanent) 0 0 14 (100)
Kurozumi et al. (2017) [22]      80% of patients with pre-operative visual disturbances had an improved visual acuity immediately after surgery 80% of patients had improved visual fields immediately after surgery
  1. aLooked at visual function (if either or both of visual acuity/visual fields were improved, unchanged or worse then the outcome was considered improved, unchanged or worse)
  2. bIt was not possible to separate the data of the patients undergoing transsphenoidal surgery from other approaches in these studies