Table 2 Data on agreement between first and second opinions

Lenza, 2017

Overall agreement: 53%

Agreement by diagnosis:

- Non-specific neck pain: 4/13 (24%)

- Radiculopathy (cervical): 36/99 (36%)

- Radiculopathy (lumbar): 116/234 (50%)

- Lumbar stenosis: 7/12 (58%)

- Failed back surgery: 26/37 (70%)

- Non-specific low back pain: 66/83 (80%)

- Cervical myelopathy: 2/2 (100%)

- Non-spinal condition: 87/0

Overall agreement: 143/425 (34%)

Agreement with the same surgical procedure recommended by the first opinion: 66/425 (16%)

- Cervical fusion: 11/71 (15%)

- Cervical disc arthroplasty (1 or 2 levels): 0/7 (0%)

- Lumbar fusion: 25/162 (15%)

- Cervical or lumbar decompression: 7/28 (25%)

- Endoscopic lumbar decompression: 0/1 (0%)

- Percutaneous decompression: 0/20 (0%)

- Percutaneous decompression and rhizotomy: 0/1 (0%)

- Stabilisation (interlaminar-interspinous): 0/8 (0%)

- Nucleoplasty: 0/5 (0%)

- Revision with fusion (cervical): 0/1 (0%)

- Revision with fusion (lumbar): 14/22 (64%)

- Steroid injection: 0/6 (0%)

- Neuro-stimulator: 0/3 (0%)

- Discography: 0/1 (0%)

- Radiofrequency rhizotomy: 8/86 (9%)

- Hardware removal: 1/1 (100%)

- Not reported: 0/2 (0%)

Gamache, 2012

55%

Namiranian, 2018

Overall agreement: 0/11 (0%)

Yanamadala, 2017

Overall agreement: 96/100 (96%)

Agreement by diagnosis

- Non-spinal condition: 4/0

Overall agreement: 42/100 (42%)

Epstein, 2011

Overall agreement: 227/274 (83%)

Epstein, 2013

Overall agreement: 72/183 (39%)

Vialle, 2015

Overall agreement: 58/94 (62%)

Viola, 2013

Overall agreement: 218/399 (55%)