Efficacy and Tolerance Study of B-DYN Versus Conventional Fusion in the Treatment of Lumbar Stenosis on the Degree of Post-operative Functional Incapacity (BDYNCLIN) (BDYNCLIN)

Efficacy and Tolerance Study of B-DYN Versus Conventional Fusion in the Treatment of Lumbar Stenosis on the Degree of Post-operative Functional Incapacity (BDYNCLIN)

Study of the Efficacy and Tolerance of the B-Dyn Medical Device Compared to a Conventional Bolted Fusion With or Without Cage in the Treatment of Degenerative Lumbar Stenosis, With or Without Grade I Spondylolisthesis on the Degree of Postoperative Functional Disability, Preservation of Mobility and Prevention of the Adjacent Syndrome". Interventional, Prospective, Comparative, Randomized, Non-inferiority, Single Blind, International, Multicenter Clinical Study

Degenerative Lumbar Spinal Stenosis (LSS) is an extremely common condition affecting more than 102 million people each year. It is a narrowing of the spinal canal in the lower back. It causes pain and even disorders of the lower limbs. When the symptoms get worse and the individual feels functional discomfort despite medical treatment, surgical intervention is recommended. Two surgical options are available: Rigid Stabilization Devices as conventional fusion with or without cage, or dynamic stabilization system as B-DYN device, this system is called "dynamic" because it allows the stabilization of the operated part while preserving a certain mobility. The main objective of this study is to evaluate the efficacy and tolerance of B-Dyn versus conventional bolted fusion (with or without cage) in the treatment of degenerative lumbar stenosis (DLS) on the degree of postoperative functional incapacity. So the investigator's hypothesis is that the use of the B-DYN device in the treatment of DLS could lead to the maintenance of functional disability related to low back pain (maintenance of walking and mobility). Another important point to be demonstrated in this study is the preservation of the mobility of the stage overlying the assembly performed by B-Dyn. Indeed, the continued degeneration of segments adjacent to lumbar vertebral fusions is a concern for surgeons For B-Dyn, which is a dynamic stabilization, the combination of rigid and flexible parts allows the mobility of the overlying stage to be preserved and could also lead to a decrease in adjacent syndrome in the long-term compared to the use of conventional fusion. The duration of patient follow-up is 60 months. The inclusion period is 24 months to recruit the necessary number of subjects for the study (a total of 216 patients is expected).

The patient will be blinded from the randomizing arm. As the procedure is performed under general anaesthesia, the patient will not be informed whether or not the B-Dyn® device has been implanted as a result of the procedure. The primary endpoint (the ODI being a reported outcome patient) will therefore be assessed blind to the randomizing arm. Other secondary endpoints such as quality of life or pain intensity will also be assessed blindly from the randomizing arm (patient assessment). Blinding of the surgeon is not possible. The device cannot be blinded from the surgeon's view.

The surgical technique for placement of the B-Dyn device is performed under general anaesthesia. The procedure begins with the insertion of the first upper polyaxial screw which is screwed in with the polyaxial screwdriver. The use of the phantom (Trial 10) is necessary in order to position the second screw. Once the screws are positioned, the B-Dyn is taken between the jaws of the gripping forceps in order to insert it into the heads of the polyaxial screws. The movable rod of the B-Dyn is then placed in the head of the upper screw. The positioning mark of the fixed rod must be placed facing the operator and in the center of the lower screw head. Finally the cap of the lower polyaxial pedicle screw is tightened. A final tightening of the two plugs on the polyaxial pedicle screw heads is performed to fix the assembly.

The surgeon will complete his gesture by placing 2 screws in the upper vertebra and 2 screws in the lower vertebra; the screws will be connected to each other to stabilize the assembly. This type of surgery is done via posterior approach and under general anaesthesia.

The surgical technique for placement of the B-Dyn device is performed under general anaesthesia. The procedure begins with the insertion of the first upper polyaxial screw which is screwed in with the polyaxial screwdriver. The use of the phantom (Trial 10) is necessary in order to position the second screw. Once the screws are positioned, the B-Dyn is taken between the jaws of the gripping forceps in order to insert it into the heads of the polyaxial screws. The movable rod of the B-Dyn is then placed in the head of the upper screw. The positioning mark of the fixed rod must be placed facing the operator and in the center of the lower screw head. Finally the cap of the lower polyaxial pedicle screw is tightened. A final tightening of the two plugs on the polyaxial pedicle screw heads is performed to fix the assembly.

The surgeon will complete his gesture by placing 2 screws in the upper vertebra and 2 screws in the lower vertebra; the screws will be connected to each other to stabilize the assembly. This type of surgery is done via posterior approach and under general anaesthesia.

Evaluation of change from baseline degree of functional disability, related to low back pain, by using the Oswestry Disability Index (ODI) at 12th month post-surgery

The Oswestry questionnaire helps assess the symptoms and severity of back pain, as well as the impairment on daily life activities. The questionnaire contains 10 questions, concerning: pain, personal care, loads, walking ability, sitting position, standing position, sleep, sexual life, social life, travels. Each question offers 6 answers, with a score of 0 to 6 that the patient must choose; score 0 corresponds to a normal function, and score 6 to a very diminished function. The score obtained is multiplied by 2 to get a percentage of disability, with 0% for the absence of disability, and 100% for the most important disability. Completion of the test takes about 5 minutes

Measuring the mobility of the instrumented level and adjacent levels at inclusion, 2 months, 12 months and 60 months post intervention using dynamic X-rays of the lumbar spine:

Dynamic X-ray is a radiograph to measure the mobility of instrumented level and adjacent one. During this radiograph, the patient will be asked to bend down until he/she reaches the painful threshold in flexion and extension, and in lateral inclination. This image should focus on the instrumented level. The degree of mobility is calculated by subtracting the angle that is formed in flexure by the tangent of the upper layer of the upper vertebra, and the tangent of the lower layer to the angle formed by these extending tangents.

Measuring the evolution of the degree of functional disability related to lumbar and radicular pain by the Oswestry Disability Index (ODI) at inclusion, 2 months, 12 months and 60 months post-intervention;

The Oswestry questionnaire helps assess the symptoms and severity of back pain, as well as the impairment on daily life activities. The questionnaire contains 10 questions, concerning: pain, personal care, loads, walking ability, sitting position, standing position, sleep, sexual life, social life, travels. Each question offers 6 answers, with a score of 0 to 6 that the patient must choose; score 0 corresponds to a normal function, and score 6 to a very diminished function. The score obtained is multiplied by 2 to get a percentage of disability, with 0% for the absence of disability, and 100% for the most important disability. Completion of the test takes about 5 minutes

Assessing the intensity of radicular and lumbar pain by the VAS scale (0-100) at inclusion, 2 months, 12 months and 60 months post-intervention

The visual analogue scale is shaped as a graduated ruler: from 0 to 100; 0 means that the subject has no pain and 100 is the maximum pain he can bear. It's a self-assessment scale. It is sensitive, reproducible, reliable and validated in both acute and chronic pain situations.

Assessing the quality of life by the Short Forum Health Survey(SF-12 score) at inclusion, 2 months, 12 months and 60 months post-intervention.

The Short Forum Health Survey (SF-12 test) is an abbreviated version of the Medical Outcomes Study Short-Form General Health Survey (SF-36) with only 12 of the 36 questions. The SF-12 provides two scores: a mental and social quality of life score and a physical quality of life score. The maximum value is 56 and the minimum value is 12. Higher Scores indicates better physcial and mental health

Measuring the anxiety using the Hospital Anxiety and Depression Scale (HAD) at inclusion, 2 months, 12 months and 60 months post intervention;

The HAD scale is a tool that detects anxiety and depressive disorders. It comprises 14 items rated from 0 to 3. There are seven questions related to anxiety (total A) and seven others related to the depressive dimension (total D); this provides two scores (maximum score of each score = 21)

Assessing the motion status at the instrumented level and adjacent levels (right and left), by measuring motor skills at inclusion, 2 months, 12 months and 60 months post-intervention

MRC scale will be used to evaluate the motor function: 0 means no movement/contractions, 5 means normal muscle strength). The neurological status will be assessed at the L4, L5 and S1 levels (right and left)

Assessing the sensory status at the instrumented level and adjacent levels (right and left), by measuring feeling of touch and stinging sensation at inclusion, 2 months, 12 months and 60 months post-intervention

MRC scale for sensory assesment will be used to assess the sensation of touch and sting : 0 means Absent and 2 means Normal. The motor status will be assessed at the L4, L5 and S1 levels (right and left)

Measuring different radiological parameters as lumbar lordosis (LL), instrumented level segmental lordosis, disk height, pelvic parameters by full spine radiograph

Full spine radiograph (EOS) is a face and profil X-ray, on which the sagittal alignment parameters will be measured. An independent radiologist will be in charge of the centralized reading.

Self-Paced Walking Test (SPWT) assesses walking capacity by measuring the total distance the patient can continuously walk on a flat surface at a self-selected pace, until experiencing symptoms of LSS or reaching a limit of 30 minutes.

A re-operation during the study is defined as a secondary intervention at the instrumented level or adjacent level for any reason (infectious or mechanical): revision, implant removal (explantation), fusion, need for additional fixation. etc

Radiological adjacent syndrome is considered if in simple and dynamic radiology, we will detect the narrowing of the disc height (> 3 mm), posterior opening ( > 5°) and sliding progression (> 3 mm) compared to the pre-operative data of the lateral bending radiology. Using MRI, we will follow postoperation progression of disc degeneration according to the Pfirrmann classification and the progression of spinal canal stenosis according to the classification of Imagama. The 1 grade progression of disk degeneration or spinal canal stenosis on MRI is considered an adjacent radiological syndrome.

Symptomatic adjacent syndrome is considered when clinical symptoms such as radicular pain of the segment adjacent to the treated level is confirmed by using the visual analogue scale (shaped as a graduated ruler: from 0 to 100; 0 means that the subject has no pain and 100 is the maximum pain he can bear) .

Surgical adjacent syndrome is considered if additional operation to treat clinical symptoms such as radicular pain (assessed using the visual analogue scale graduated from 0 to 100; 0 means that the subject has no pain and 100 is the maximum pain he can bear) of the segment adjacent to the treated level is required.

By evaluating Number of patients who experienced at least one adverse event during the follow-up period.

By evaluating Number of patients who experienced a serious adverse event during the follow-up period.

Inclusion Criteria: Stenosis on 1 to 3 vertebral levels (grade C or D according to Schizas classification) on MRI (lumbar spine MRI ) Spondylolisthesis grade 1 or no spondylolisthesis Pseudoclamping on one or both legs and back pain (EVA score > 30) Subjects who have failed well-managed medical treatment that has not resulted in lasting symptom relief (duration of symptoms > 6 months). Subjects with no contraindications to fusion or the application of B-Dyn®. Subjects of both sexes, 40 years of age or older of. Patient who is able to respond to the questionnaires and who can communicate in the language of the study country. Patient who has given free, informed and written consent to participate in the study Subjects affiliated to or entitled to a social security scheme Exclusion Criteria: Spondylolisthesis of grade > 1. Degenerative scoliosis (Cobb angle > 20°). History of fusion for spinal stenosis or instability. Stenosis not caused by degenerative changes. Isolated herniated disc. Other specific vertebral damage (e.g. ankylosing spondylitis, cancer or neurological disorders). History of vertebral compression fractures at the instrumented level. History of osteoporotic fractures. Psychological disorders (e.g., dementia or substance abuse) that lead to an inability to participate in the study. Intervention required on more than 3 vertebral levels. Chronic infection. Withdrawal of consent. Pregnant woman. Breastfeeding woman Participation in a clinical trial in the 3 months prior to the initial visit. Drug addiction. Predicted unavailability during the course of the study. Patient deprived of liberty or under guardianship. Allergy to any of the components of the medical device

CHU [University Hospital Center]of Bordeaux - Le Tripode - GH Pellegrin/ Department of Orthopaedic and Trauma Surgery Spinal Surgery Unit

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