Low Back Pain
Conditions
Keywords
Low back pain of suspected lumbar zygapophysial etiology
Brief summary
Lumbar zygapophysial (facet) joint pain is a common cause of low back pain. Radiofrequency (RF) denervation is an effective and low risk treatment of chronic low back pain of suspected facet joint etiology. Blocks of the medial branches innervating the joints are commonly used to localize the pain and make the diagnosis of facet joint pain. There is currently no standard number of diagnostic blocks: zero, one, and two blocks have all been utilized. Considering the high false positive and false negative rates of these blocks, the cost: benefit ratio has been questioned. No study to date has examined the practice of diagnostic medial branch blocks before RF denervation. The purpose of this study is to determine the optimal number of blocks before radiofrequency denervation. Three groups of patients will be studied. In group I, patients will undergo RF denervation based on history and physical exam alone. In group II, patients will undergo RF denervation based on a positive response to a single diagnostic block with local anesthetic. In group III, patients will undergo RF treatment only after a positive screening block and a positive confirmatory block.
Detailed description
Lumbar zygapophysial (facet) joints are recognized as one of the most common causes of chronic low back pain with an estimated prevalence among patients with LBP ranging from 15% to 40%. Radiofrequency (RF) denervation of facet joints has been utilized as an effective treatment of chronic pain attributed to these joints. Blocks of the medial branches innervating the joints are commonly used to localize the pain and make a diagnosis of lumbar zygapophysial (l-z) joint pain. However, considering the high false-positive rates of these blocks (25-40%), the false-negative rates (8-10%), and the number of blocks necessary to make the diagnosis before treatment, the cost-effectiveness of performing these blocks and the benefit of exposing these patients to additional risks is under question. The risks of RF denervation are so low (equivalent to performing the diagnostic block), some have questioned whether or not any diagnostic facet blocks should be performed before RF lesioning. The purpose of the study is to determine the optimal number of diagnostic blocks that should be performed before radiofrequency denervation in patients with chronic lower back pain with suspected facet joint etiology. In this prospective randomized study, we will recruit 150 patients with suspected chronic (l-z) joint pain without neurological symptoms to undergo one of three treatment modalities. In group I, 50 patients will undergo RF denervation based on history and physical exam alone (what we advocate in a recent review article). In group II, 50 patients will receive a single diagnostic block with 0.5% bupivacaine. Those that obtain greater than 50% pain reduction will undergo RF denervation. In group III, 50 patients will receive a block with either 2% lidocaine or 0.5% bupivacaine. Those patients that obtain greater than 50% pain relief with the first block receive a second block with the other local anesthetic. Patients that obtain greater than 50% pain relief with the second block then undergo RF. Patients in any group that obtain less than 50% pain relief with any block exit the study.
Interventions
PROCEDURERadiofrequency denervation of medial branches
Radiofrequency of medial branches that innervate the lumbar facet joints
DRUG0.5% bupivacaine
Diagnostic medial branch block with 0.5% bupivacaine. Blocking the nerves that innervate the facet joints with a long-acting local anesthetic.
DRUG2% lidocaine
Diagnostic medial branch block with 2% lidocaine. Blocking the nerves that innervate the facet joints with a short-acting local anesthetic.
PROCEDURERadiofrequency denervation
Radiofrequency lumbar facet denervation without a diagnostic block
Sponsors
Johns Hopkins University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Axial low back pain unresponsive to conservative treatment measures such as physical therapy, manual therapy and pharmacotherapy * Duration of pain greater than 6 months
Exclusion criteria
* Age younger than 18 years * Objective evidence (MRI or physical exam findings) of lumbosacral radiculopathy * Prior radiofrequency treatment * Significant spinal stenosis or spondylolisthesis * Previous back surgery * Uncorrected coagulopathy * Unstable medical or psychiatric condition * Pregnancy * Allergies to local anesthetic
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Cost Per Successful Procedure | 3-months | Total cost per effective treatment at 3-months. Successful procedure defined as greater or equal to 50% pain relief and satisfaction lasting at least 3 months. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Successful Treatment | 3-months postprocedure | Greater or equal to 50% pain relief plus procedural satisfaction lasting at least 3 months. What is being measured is the number of participants with a positive outcome. |
Countries
United States
Participant flow
Recruitment details
151 patients with axial low back pain and suspected lumbar facet arthropathy were recruited from pain clinics at Johns Hopkins and Walter Reed between January 2007 and April 2009 for lumbar facet interventions.
Pre-assignment details
Subjects had to be candidate for facet blocks or radiofrequency denervation. They had to have no neurological symptoms, failed conservative treatment and not had spinal fusion.
Participants by arm
| Arm | Count |
|---|---|
| Double-block Group Radiofrequency lumbar facet joint denervation only if positive response to 2 diagnostic facet blocks. | 50 |
| Single-block Group Radiofrequency lumbar facet joint denervation if positive response to single facet joint block. | 50 |
| Radiofrequency Group Radiofrequency lumbar facet denervation without a diagnostic facet block. | 51 |
| Total | 151 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 | FG002 |
|---|---|---|---|---|
| Overall Study | Lost to Follow-up | 1 | 1 | 0 |
Baseline characteristics
| Characteristic | Double-block Group | Single-block Group | Radiofrequency Group | Total |
|---|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 6 Participants | 6 Participants | 6 Participants | 18 Participants |
| Age, Categorical Between 18 and 65 years | 44 Participants | 44 Participants | 45 Participants | 133 Participants |
| Sex: Female, Male Female | 23 Participants | 24 Participants | 20 Participants | 67 Participants |
| Sex: Female, Male Male | 27 Participants | 26 Participants | 31 Participants | 84 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk |
|---|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — | — / — |
| other Total, other adverse events | 0 / 50 | 0 / 50 | 0 / 51 |
| serious Total, serious adverse events | 0 / 50 | 0 / 50 | 0 / 51 |
Outcome results
Primary
Cost Per Successful Procedure
Total cost per effective treatment at 3-months. Successful procedure defined as greater or equal to 50% pain relief and satisfaction lasting at least 3 months.
Time frame: 3-months
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Double-block Group | Cost Per Successful Procedure | 15,241 U.S. dollars |
| Single-block Group | Cost Per Successful Procedure | 17,142 U.S. dollars |
| Radiofrequency Group | Cost Per Successful Procedure | 6286 U.S. dollars |
Secondary
Successful Treatment
Greater or equal to 50% pain relief plus procedural satisfaction lasting at least 3 months. What is being measured is the number of participants with a positive outcome.
Time frame: 3-months postprocedure
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Double-block Group | Successful Treatment | 9 participants |
| Single-block Group | Successful Treatment | 7 participants |
| Radiofrequency Group | Successful Treatment | 17 participants |