Table 1 Study characteristics

Aejmelaus 1984 [47]

Retrospective, secondary care, Finland

200 patients; 54.5% male (of n = 200), mean age 43.8 (range 14–82)

Diagnosis of disc herniation (68.4%)

Patient level; 95 patients on lumbar spine surgery

Myelo: contrast medium metrizamide (Amipaque, 170-200 mg iodine/ml)

Bernard 1994 [44]

Prospective study, secondary care, USA

33 patients persistent/ recurring symptoms after lumbar surgery: 61% male; age range: 23–74 years

Recurrent lumbar disc herniation (69.7%)

Patient level

MRI: 0.5Tesla MRI (29 patients) or 1.5Tesla MRI (4 patients) including spin echo T1 and T2 sagittal images

2 observers assessed each patient = 66 responses

Birney 1992 [45]

Prospective study, secondary care, USA

90 patients with LBP or radicular pain refractory to ≥3 months of conservative, non operative treatment; 57 underwent surgery; 53% males age range 20–71 years

Lumbar disc herniation and/ or degenerative disc disease (98.7%)

Disc level; 76 disc levels of 57 operated patients

MRI: 0.35Tesla MRI. Axial images and sagittal images

Bischoff 1993 [43]

Retrospective study, secondary care, USA

57 patients for lumbar spine surgery; 51% male; age range: 20–79 years

HNP (48.6%)

Disc level; 72 levels assessed of 47 operated patients

Myelo: infusion of 16 ml Omnipaque 180 solution

MRI: 1.5Tesla MRI; sagittal and axial T1 and T2 weighted images

Chawalparit 2006 [46]

Prospective study, secondary care, Thailand

123 LBP patients and suspected lumbar disc herniation; 50% male; age range: 21–60 years

Lumbar disc herniation (69.7%)

Patient level; 33 operated patients

MRI: full protocol; 1.5Tesla; sagittal T1 weighted images, sagittal T2 weighted images and axial T2 weighted images

54 patients treated conservatively and 36 lost to follow up; excluded from analysis

Claussen 1982 [34]

Prospective, Secondary care, Germany

77 patients with suspected disc prolapse, 46.7% male;

Disc prolapse (92.3%)

Patient level; 26 patients operated

CT: Somatom II, 10s; 125 kV, 460mHz

Myelo: metrizamide (amipaque)

Firooznia 1984 [35]

Prospective, Secondary care, Germany

100 patients who underwent surgery for sciatica: 61% male, mean age 49 (19–76) years

Disc prolapse (90.5%)

Disc level; 116 levels assessed of 100 patients

CT: GE 8800 CT/T, 25 cm circular calibration, 250-400 mA, 120 kVp, 9.6 s

Forristall 1988 [36]

Prospective, Secondary care, USA

32 patients with suspected lumbar disc herniation: 78% male, mean age 45 (22–74) years

HNP with neural compression (77.4%)

Disc level; 31 levels assessed in 25 operated patients

CT: Picker 1200 Synerview, 14 cm, 65 mA, 130 kV, 5 mm slice thickness, 5 ml of Amipaque 180 mg/ml

MRI: 1.5Tesla MRI sagittal T1 and T2 weighted images; Proton density and T2 weighted axial images

Gillstrom 1986 [37]

Prospective, Secondary care, Sweden

90 patients with suspected herniated discs 59.4% male, age range 23–74 years

Lumbar disc herniation

Patient level; 37 operated patients

CT: General Electris GT/T 8800 unit

Myelo: Metrizamide contrast solution

Jackson 1989 I [38]

Prospective, Secondary care, USA

124 patients with LBP and leg pain, refractory to conservative management: 70% male, mean age 43 (21–76) years

HNP: protruded, extruded, and sequestrated disc (54.1%)

Disc level; 231 levels assessed of 124 patients

CT: Siemens Somatom, 5 mm slice thickness with 1 mm overlap

Myelo: infusion of 14 ml metrizamide (Amipaque) of 180 mg iodine/ml

Jackson 1989 II [39]

Prospective, Secondary care, USA

59 patients with LBP and leg pain refractory to conservative management: 56% male, mean age 40 (18–70) years

HNP: protruded, extruded, and sequestrated disc (49.2%)

Disc level; 120 levels assessed of 59 patients

CT: Siemens Somatom, 5 mm slice thickness with 1 mm overlap using bone and soft tissue settings

Myelo: infusion of 14 ml iohexol (Omnipaque) of 180 mg iodine/ml

MRI: 1.5Tesla MRI Sagittal T1 and T2 weighted images and axial T1 weighted images

Milano 1991 [40]

Prospective, Italy

40 surgical patients; 57.5% male; mean age 43 (range 27–60)

Lumbar intervetrebral disc disease (50%)

Disc level; 80 discs examined

CT: Somaton DR CT scan, slices of 4 mm

Schaub 1989 [41]

Retrospective, Secondary care, Swiss

29 patients with recurring symptoms after lumbar disk surgery: 48% male, mean age 49 (SD:13) years

HNP (62.1%)

Patient level

CT: No information

Myelo: No information

Schipper 1987 [42]

Prospective, Secondary care, Netherlands

235 patients with radiating leg pain, referred to the neurosurgical department: 61% male, mean age 43 years

Lumbar disc herniation: (83.8%)

Patient level

CT: Philips Tomoscan 350, 200 As, 120 kV, 3 mm slice thickness

Myelo: 15 ml Iopamiro 200LBP: low back pain