Are Paraspinous Intramuscular Injections of Botulinum Toxin A (BoNT-A) Efficient in the Treatment of Chronic Low-back Pain (LBP)?

Study Overview
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Brief Summary
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Studying the therapeutic effect of paravertebral injections of BoNT-A (botulinum toxin A) requires further studies to confirm the reported short-term therapeutic effect and to determine potential predictive factors of efficacy.

Detailed Description
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This study was a randomized, double-blinded, placebo-controlled phase 3 trial comparing BoNT-A Type A injections to a placebo in patients with chronic Low-back Pain (LBP). This superiority trial obtained support from the French Hospital Clinical Research Project (PHRC) and the approval of a French ethics committee (2003/02) (Comité Sud-Ouest et Outre-Mer III, consent obtained in February 2003). The number of participants included in the study was chosen to be similar as those included in previous studies, that showed a strong positive effect of BoNT-A injections on LBP. Furthermore, the design of our study (i.e. a crossover) increased the power of the statistical analysis. A scientific committee has been solicited at this step, after including 19 patients, to assess the results.

Official Title
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Are Paraspinous Intramuscular Injections of Botulinum Toxin A (BoNT-A) Efficient in the Treatment of Chronic Low-back Pain?

Conditions
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Chronic Low-back Pain

Intervention / Treatment
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* Drug: Botox
* Drug: Placebos


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: LBP defined as a pain located between the thoracic lumbar hinge and the gluteal sulcus, where pain had evolved over a period of 6 months despite well conducted medical treatment, self-assessed lumbar pain intensity over 50 millimeters long on a visual analogue scale of 100 millimeters (0=no pain; 100=maximal pain), having been on sick leave for 60 or more days in the year preceding the inclusion (in order to include patients with high consequences of chronic low-back pain on their work), same long-term chronic pain treatment for at least 6 weeks Exclusion Criteria: age under 18 or over 55 years (to avoid secondary causes of low back pain, like spinal tumor), ongoing pregnancy or breast-feeding, a neuromuscular pathology (myasthenia gravis, amyotrophic lateral sclerosis, myopathy, polymyositis), aminoglycoside treatment at the time of inclusion, skin infection at injection points, diabetes and alcoholism (in order to avoid other etiologies of chronic pain), a history of injecting BoNT-A A, anticoagulation treatment, sciatica, suspected spinal inflammatory disorder (spondylitis, inflammatory rheumatism, tumoral pathology), a failed back surgery syndrome (when surgery failed to relieve low-back pain), - incapacity to stand, cardiorespiratory deficiency which does not allow the isokinetic exploration of the spinal muscles, cognitive disorders limiting patient participation, conflicts of interest owing to existing pain (unconsolidated work accident, ongoing damage compensation). Spine infection, tumour or trauma had been specifically excluded by an MRI done by all patients before the inclusion in the present study. No patient was allowed to take opiates during the time of the study, facet joint injections were also not permitted during the study period.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: This study was a randomized, double-blinded, placebo-controlled phase 3 trial comparing Intramuscular injections of botulinum toxin A to a placebo in patients with chronic low-back pain (LBP)
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: botulinum toxin A<br> | Drug: Botox<br>* single injection of 200 International Unit of BoNT-A in 10 bilateral paravertebral intramuscular points for treating chronic LBP<br>|
| Placebo Comparator: Placebo<br> | Drug: Placebos<br>* 4 ml of physiological serum injected intramuscularly into the lumbar paravertebral muscles.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| effect of paravertebral injections of BoNT-A, 30 days after its administration in chronic LBP sufferers. | Pain intensity was measured on a horizontal visual analogue scale (VAS) 100 mm long, with  no pain  written on one end and  maximum pain  on the other. The question asked was: How was the intensity of your LBP over the last 8 days? | Day 30 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Evaluate the analgesic effect of paravertebral injections of BoNT-A, 90 days after its administration in chronic LBP sufferers. | Initial pain was detailed as follows: Immediate average LBP was recorded on VAS at the first injection | Day 90 | 
| Measure the impact of paravertebral injections of 200 IU of BoNT-A in a single administration on lumbar stiffness and on spinal extensor muscle strength in patients with chronic LBP. | Lumbar pain intensity was measured on a horizontal visual analogue scale 100 mm long, with  no pain  written on one end and maximum pain on the other. The question asked was: How was the intensity of your LBP over the last 8 days? The question asked was: How was the intensity of your LBP over the last 8 days? | Day 30 | 
| Measure the impact of paravertebral injections of 200 IU of BoNT-A in a single administration on lumbar stiffness and on spinal extensor muscle strength in patients with chronic LBP. | Lumbar pain intensity was measured on a horizontal visual analogue scale 100 mm long, with  no pain  written on one end and maximum pain on the other. The question asked was: How was the intensity of your LBP over the last 8 days? The question asked was: How was the intensity of your LBP over the last 8 days? | Day 120 |