Sagittal proton density-weighted Dixon sequence on the lumbar spine and axial T2-weighted spin echo sequence on the lumbar discs.

The classification by Michael MODIC evaluates the stage of disc degeneration seen with magnetic resonance imaging as follows :

Stage 0 : Disc appears black on sequences 1 and 2. Dehydration of disc without retraction of the vertebral end plates.

Stage 1 : Disc appears black on sequence 1 but white on sequence 2. Inflammatory reaction on vertebral end plates. Swollen aspect.

Stage 2: Disc appears white on both sequences 1 and 2. Fatty reaction of vertebral end plates. Fatty aspect.

Stage 3: Disc appears black on both sequences 1 and 2. Bony sclerosis.

The modified Pfirmann classification is used to grade disc degeneration as seen on magnetic resonance imaging with T2-weighted sagittal or STIR sequences. Grade 1 corresponds to a healthy disc rarely observed in adults. Grade 5 corresponds to disk collapse.

The modified Pfirmann classification is used to grade disc degeneration as seen on magnetic resonance imaging with T2-weighted sagittal or STIR sequences. Grade 1 corresponds to a healthy disc rarely observed in adults. Grade 5 corresponds to disk collapse.

The number of points of degeneration, just above or just below the operated segment, will be counted for each patient.

The number of points of degeneration, just above or just below the operated segment, will be counted for each patient.

The Weishaupt classification classifies arthritis of the lumbar facet joints as follows:

Grade 0: Normal facet joint space (2±4 mm width) Grade 1: Narrowing of the facet joint space (< 2 mm) and/or small osteophytes and/or mild hypertrophy of the articular process Grade 2: Narrowing of the facet joint space and/or moderate osteophytes and/or moderate hypertrophy of the articular process and/or mild subarticular bone erosions Grade 3: Narrowing of the facet joint space and/or large osteophytes and/or severe hypertrophy of the articular process and/or severe subarticular bone erosions and/or subchondral cysts

The Weishaupt classification classifies arthritis of the lumbar facet joints as follows:

Grade 0: Normal facet joint space (2±4 mm width) Grade 1: Narrowing of the facet joint space (< 2 mm) and/or small osteophytes and/or mild hypertrophy of the articular process Grade 2: Narrowing of the facet joint space and/or moderate osteophytes and/or moderate hypertrophy of the articular process and/or mild subarticular bone erosions Grade 3: Narrowing of the facet joint space and/or large osteophytes and/or severe hypertrophy of the articular process and/or severe subarticular bone erosions and/or subchondral cysts

Backache has an effect on the muscles provoking a gradual degeneration of muscle fat. Hadar proposes a 3-stage scale to classify the fibroadipose tissue.

Backache has an effect on the muscles provoking a gradual degeneration of muscle fat. Hadar proposes a 3-stage scale to classify the fibroadipose tissue

The number of re-interventions among spinal fusion patients will be recorded as a percentage.

The number of re-interventions among lumbar arthroplasty patients will be recorded as a percentage.

The DN4 hetero-questionnaire (" Neuropathic pain in 4 Questions ") is validated in French and evaluates the possible presence of neuropathic-type pain in a patient (Bouhassira et al. 2005). It consists of 4 questions (2 at the interview, 2 during the examination and 10 items for which the patient has to answer YES or NO. Each " YES" validates one point, each " NO " does not validate a point. If the score is ≥4,the test is positive.

The DN4 hetero-questionnaire (" Neuropathic pain in 4 Questions ") is validated in French and evaluates the possible presence of neuropathic-type pain in a patient (Bouhassira et al. 2005). It consists of 4 questions (2 at the interview, 2 during the examination and 10 items for which the patient has to answer YES or NO. Each " YES" validates one point, each " NO " does not validate a point. If the score is ≥4,the test is positive.

The Oswestry Disability Index is one of the most widely-used disability scales in the Anglophone world used to evaluate functional incapacity in patients with backache. It may be used not only in clinical studies but also by the General Practitioner to evaluate the evolution of a patient's functional incapacity. It contains 10 sections and at least 8 must be completed in order for the score to be calculable. It is expressed as percentage incapacity by multiplying by two the sum of the answers graduated 0 to 5 for each item. It has been validated in English ( Fisher & Johnston 1997; Little et MacDonald 1994; Fritz et Irrgang 2001; Grönblad et al. 1993; Fairbank and Pynsent 2000) and its French translation was validated in 2008 (Vogler et al. 2008).

The Oswestry Disability Index is one of the most widely-used disability scales in the Anglophone world used to evaluate functional incapacity in patients with backache. It may be used not only in clinical studies but also by the General Practitioner to evaluate the evolution of a patient's functional incapacity. It contains 10 sections and at least 8 must be completed in order for the score to be calculable. It is expressed as percentage incapacity by multiplying by two the sum of the answers graduated 0 to 5 for each item. It has been validated in English ( Fisher & Johnston 1997; Little et MacDonald 1994; Fritz et Irrgang 2001; Grönblad et al. 1993; Fairbank and Pynsent 2000) and its French translation was validated in 2008 (Vogler et al. 2008).

The notions of apprehension-avoidance of beliefs font part of the psychosocial factors associated with the onset, maintenance and reinforcement of the chronic pain process. Their evaluation is made with the FABQ questionnaire whose original English version was validated in 1993 by Waddell et al. (1993) and the French version in 2004 (Chaory et al.2004). The patient's fears, beliefs and avoidance attitudes are predictive of the result and observance of treatment, particularly functional restoration programs (Pfingsten et al. 2000). The FABQ is a self-questionnaire with 16 items rated 0 to 6 on a Likert scale (0 = absolutely disagree, 6 = completely agree) ; the questions focus on the appreciation of notions of apprehension relative to professional activities and other physical activities. It takes about 10 minutes to complete the questionnaire. A high score represents a high rate of fears and beliefs.

The notions of apprehension-avoidance of beliefs font part of the psychosocial factors associated with the onset, maintenance and reinforcement of the chronic pain process. Their evaluation is made with the FABQ questionnaire whose original English version was validated in 1993 by Waddell et al. (1993) and the French version in 2004 (Chaory et al.2004). The patient's fears, beliefs and avoidance attitudes are predictive of the result and observance of treatment, particularly functional restoration programs (Pfingsten et al. 2000). The FABQ is a self-questionnaire with 16 items rated 0 to 6 on a Likert scale (0 = absolutely disagree, 6 = completely agree) ; the questions focus on the appreciation of notions of apprehension relative to professional activities and other physical activities. It takes about 10 minutes to complete the questionnaire. A high score represents a high rate of fears and beliefs.

This provocation test is very specific to radicular sciatica . Raising the lower limb with the knee in extension, reproduces sciatica pain if there is an impression of disk pain with its origin at the roots of the sciatica nerve L5 and S1. This test is evaluated by the degree of elevation of the lower limb relative to the examination table. During the Lasègue manoeuvre the sciatica pain is improved during dorsal flexion of the foot.The doctor notes whether the Lasègue manoeuvre done on the healthy side exacerbates the pain on the opposite side. It is said that contralateral Lasègue sign is positive.

This provocation test is very specific to radicular sciatica . Raising the lower limb with the knee in extension, reproduces sciatica pain if there is an impression of disk pain with its origin at the roots of the sciatica nerve L5 and S1. This test is evaluated by the degree of elevation of the lower limb relative to the examination table. During the Lasègue manoeuvre the sciatica pain is improved during dorsal flexion of the foot.The doctor notes whether the Lasègue manoeuvre done on the healthy side exacerbates the pain on the opposite side. It is said that contralateral Lasègue sign is positive.

This quality of life self-evaluation scale is a short version of the SF-36 and gives two scores: one mental and social quality of life score, and one physical quality of life score (Ware et al. 1996). For the scoring (1) each answer to 12 items must be converted into standardized values both for the mental and social score and for the physical score, (2) the 12 standardized values obtained for the mental et social score are added together and (3) 60,75781 is added on to get the mental et social quality of life score. Then, the 12 standardized values obtained for the physical score are added together and 56,57706 is added on to get the physical quality of life score.

This quality of life self-evaluation scale is a short version of the SF-36 and gives two scores: one mental and social quality of life score, and one physical quality of life score (Ware et al. 1996). For the scoring (1) each answer to 12 items must be converted into standardized values both for the mental and social score and for the physical score, (2) the 12 standardized values obtained for the mental et social score are added together and (3) 60,75781 is added on to get the mental et social quality of life score. Then, the 12 standardized values obtained for the physical score are added together and 56,57706 is added on to get the physical quality of life score.

The Patient Global Impression of Change scale is a self-questionnaire on satisfaction regarding the change brought by the treatment to daily activities, symptoms and quality of life in relation to chronic pain. This scale has been validated in French (Le Gal et al. 2010) and consists of 7 points. The patients are classified into 3 categories according to their score (Rampakakis et al. 2015): deterioration (a score of 1 to 3), stable (score of 4), improvement (score of 5 to 7).

The Patient Global Impression of Change scale is a self-questionnaire on satisfaction regarding the change brought by the treatment to daily activities, symptoms and quality of life in relation to chronic pain. This scale has been validated in French (Le Gal et al. 2010) and consists of 7 points. The patients are classified into 3 categories according to their score (Rampakakis et al. 2015): deterioration (a score of 1 to 3), stable (score of 4), improvement (score of 5 to 7).

A 3T MRI scanner (Magnetom Skyra, Siemens Healthcare) equipped with a 32-channel head coil will be used to obtain the following sequences: sagittal proton density-weighted Dixon sequencing on the lumbar spine and axial T2-weighted spin echo sequencing on the lumbar discs.

A 3T MRI scanner (Magnetom Skyra, Siemens Healthcare) equipped with a 32-channel head coil will be used to obtain the following sequences: sagittal proton density-weighted Dixon sequencing on the lumbar spine and axial T2-weighted spin echo sequencing on the lumbar discs.

The patient's weight and height will be noted in an observation booklet and the patient's body mass index will be calculated via a computer (in kg/m2)

The patient's weight and height will be noted in an observation booklet and the patient's body mass index will be calculated via a computer (in kg/m2)