Threshold Response of Lumbar Selective Nerve Root Block in Predicting Good Outcome Following Lumbar Foraminotomy

Study Overview
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Brief Summary
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SNRB, as measured by the change in pain and objective functional ability, can solicit crucial information regarding a patient's clinical picture and can predict a patient's outcome post-surgery. By using the walk test as an objective functional assessment, the aim is to better standardize the threshold for a positive response to SNRB. In summary, SNRB, despite utilized frequently in the diagnostic work-up with patients with lumbar radiculopathy, vary widely in their sensitivity and specificity. The reasons, as outlined above, are multifactorial. The proposed study aims to minimize the known limitations of these injections and prospectively define their positive and negative predictive value in a homogenous group of patients undergoing surgery for lumbar foraminal stenosis and radiculopathy. The design will define a threshold of response utilizing both subjective and objective measures and more accurately predict excellent results following surgery.

Detailed Description
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The proposed study will identify the threshold response level that quantifies the predictive value of diagnostic SNRBs in patients who present with lumbar foraminal stenosis and radiculopathy. Specifically, the proposed study will address the question of whether there is a degree or length of response to SNRB, which predicts an excellent surgical outcome. The hypothesis is that diagnostic SNRBs, when performed correctly, are useful in localizing the level of involvement in LSS and improve the accuracy and efficacy of surgical intervention. Use of diagnostic SNRBs will thus be used to clarify the clinical picture, giving the surgeon the information to make the right decision to operate or not, and, in the case of operation, predicting the optimal level(s) for surgical intervention. In addition, the investigators plan to identify and fully characterize a standard threshold level and time of nerve block response that will optimize the accuracy, specificity, and sensitivity of SNRB in predicting surgical outcomes.

Official Title
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Defining the Threshold Response of Lumbar Selective Nerve Root Block in Predicting Good Outcome Following Lumbar Foraminotomy

Conditions
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Back Pain, Radiculopathy Lumbar, Degenerative Lumbar Spinal Stenosis

Intervention / Treatment
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* Drug: Selective Nerve Root Block


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Ages 18-80 Diagnosis of unilateral lower extremity radiculopathy due to degenerative foraminal stenosis Patients scheduled for an associated lumbar foraminotomy procedure Diagnosis of radiculopathy with imaging and/or clinical history or physical exam that does not demonstrate a clear neurogenic source of their pain Subjects must be available for the entire study duration (12 months) Exclusion Criteria: Patients will be excluded if there is a clear correlation between imaging and radiculopathy Radiculopathy associated with trauma, tumor or infection. Non-radicular lower extremity pain will also be excluded Patients who cannot tolerate the SNRB without IV sedation Surgery requiring multi-level decompression and/or fusion Surgical indication for malignancy, injection or acute or emergency trauma History of major surgery within 3 months prior to enrollment Pregnant females Presence of severe acute, chronic medical or psychiatric condition

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 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: Diagnostic
Intervention Model: Single Group Assignment
Interventional Model Description: Subjects will be enrolled into a single treatment participant pool.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Selective Nerve Root Block<br>Patient will receive a Selective Nerve Root Block injection at the target level prior to surgical intervention. | Drug: Selective Nerve Root Block<br>* Prior to single level foraminotomy for lumbar foraminal stenosis, patients will undergo SNRB of the suspected nerve root. Patients will undergo surgery despite the response to injection. Patients will complete an ambulation assessment immediately before and after the injection. Distance and time will be noted. Patients will be called within 48 hours of injection to determine response to injection, and recorded as Pre-and Post-injection VAS leg as well as duration of the response. Patients will be seen at 6 weeks, 3,6, and 12 months post-surgery and outcome measured by VAS-leg, ODI, PDQ and EQ-5D scores. Data will be used to determine the ideal improvement in leg pain and duration of improvement, predicting a statistical and meaningful improvement in leg pain following foramintomy.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Visual Analog Scale (VAS) Leg Pain Score | Aim: 0-2 point improvement The Visual Analogue Scale (VAS) consists of a straight line with the endpoints defining extreme limits such as 'no pain at all' (0) and 'pain as bad as it could be' (10). The patient is asked to mark their pain level on the line between the two endpoints. The distance and change between '0' and the mark then defines the subject's pain. This will be measured at each subject visit. | 12-months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Oswestry Disability Index Questionnaire (ODI) | Aim: 15-point improvement The Oswestry Disability Index (ODI) is one of the principal condition-specific outcome measures used in the management of spinal disorders. The ODI is the most commonly outcome measures in patients with low back pain. Structure / Content There are 10 questions. The questions are designed in a way that to realize how the back or leg pain is affecting the patient's ability to manage in everyday life. Scoring Method Each of the 10 items is scored from 0 - 5. The maximum score is therefore 50. The score can be multiplied by 2 to produce a percentage. If the FIRST statement is marked, the section score = 0, If the LAST statement is marked, it = 5 Interpretation 1.0%-20%: Minimal disability. Usually no treatment is indicated. 2.20%-40% Moderate disability 3.40%-60%: Severe disability 4.60%-80%: Crippled 5.80%-100%: These patients are either bed-bound or exaggerating their symptoms. | 12-Months | 
| EQ-5D Questionnaire | Aim: Improvement in quality of life The descriptive system comprises five dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety/depression. Each dimension has 5 levels: no problems, slight problems, moderate problems, severe problems and extreme problems. The patient is asked to indicate his/her health state by ticking the box next to the most appropriate statement in each of the five dimensions. This decision results in a 1-digit number that expresses the level selected for that dimension. The digits for the five dimensions can be combined into a 5-digit number that describes the patient's health state. The questionnaire also records the patient's self-rated health on a vertical visual analogue scale, where the endpoints are labeled 'The best health you can imagine' and 'The worst health you can imagine'. The VAS can be used as a quantitative measure of health outcome that reflect the patient's own judgement. | 12-Months | 
| Pain Disability Questionnaire (PDQ) | Aim: 26-point improvement The Pain Disability Questionnaire (PDQ) assesses perception of disability in relation to pain. PDQ scores: mild/moderate (0-70), severe (71-100), and extreme (101-150). | 12-months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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lumbar, back pain, lumbar spine pain, nerve root block, foraminotomy, radiculopathy, foraminal stenosis