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 56 months to recruit the necessary number of subjects for the study (a total of 216 patients is expected).
Stenosis on 1, 2 or 3 disc levels (grade B or C or D according to Schizas classification or central stenosis of grade A according to Schizas classification with a lateral stenosis (postero-lateral overhang or disc protrusion)) on MRI (lumbar spine MRI )
Spondylolisthesis grade 1 or no the upper surgical (treated) level
Neurological impairment or neurogenic claudication on one or both legs (VAS score > 30)
Subjects who have failed well-managed medical treatment that has not resulted in long-lasting symptom relief (duration of symptoms > 3 months);
Spondylolisthesis of grade > 1 on the upper surgical (treated) level
Intervention required on more than 3 disc levels
Degenerative Scoliosis (Cobb angle > 20°);
Stenosis located only on the L5-S1 level
Parallel
B-DYN
DeviceThe 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.
Conventional Bolted fusion (with or without cage)
DeviceThe 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 upper 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, 24 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, 24 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, 24 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
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Quanta Medical
Lead sponsor
Cousin Biotech
Collaborator
