Table 1 A summary of diagnostic criteria and characteristics of FBSS

Merskey et al. [8]

Lumbar (cervical) pain of unknown origin either persisting despite surgical intervention or appearing after surgical intervention for spinal (origin) pain originally in the same topographical distribution

-Unknown origin

Leveque et al. [9]

Chronic radicular pain that has recurred or persists in the same distribution despite anatomically satisfactory previous spinal surgery

-Recurred or persists

-Anatomically satisfactory surgery

Waguespack et al. [10]

The outcome of lumbar spine surgery does not meet the pre-surgical expectations of the patient and surgeon

-Didn’t meet the pre-surgical expectations

Kumar et al. [11]

Patients suffer from chronic neuropathic pain with a mean leg pain intensity of > 5 cm on a Visual Analog Scale (VAS) from 0 to 10 cm following anatomically successful spinal surgery

-Anatomically satisfactory surgery

-VAS > 5/10

Bokov et al. [12]

Patients with a pain intensity of no less than 40 on the 100-point VAS and at least a 40% decrease on the Oswestry Disability Index (ODI)

-VAS > 40/100

-ODI decrease < 40%

Bordoni et al. [5]

Patient who underwent spinal surgery, irrespective of type or intervention area, with persistent pain in the lumbosacral region with or without it radiating to the leg despite the intervention for up to 3 months

-The duration of symptoms > 3 months and conservative treatment was ineffective

Andres et al. [13]

Patients with chronic, intractable pain (> 5/10 on Numeric Rating Scale) of the trunk and/or limbs that has remained refractory to conservative therapy for at least 6 months

-The duration of symptoms > 6 months

-NRS > 5/10

Cho et al. [14]

Patients show chronic back pain or leg pain after successfully performed lumbar surgery without specific reasons such as compressive lesions, infection

-