Indirect vs. Direct Decompression for Treatment of Central Stenosis: RCT

Study Overview
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Brief Summary
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This is a prospective, randomized clinical trial of patients undergoing 1-level lateral lumbar spinal fusion. This study seeks to randomize patients indicated for Lateral Lumbar Interbody Fusion (LLIF) into one of two groups: direct decompression and indirect decompression.

Detailed Description
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While indirect decompression has been largely accepted as a strategy to treat foraminal stenosis, there is some disagreement regarding its efficacy in treating patients with central and lateral recess stenosis. The current study seeks to randomize patients indicated for Lateral Lumbar Interbody Fusion (LLIF) into one of two groups: direct decompression and indirect decompression. Enrolled participants will be evaluated before surgery, during their hospital course and post-operatively at 6 weeks, 3 months, 6 months, 1 and 2 years. Operative details, complications, reoperation rates, patient reported outcomes, clinical and radiographic outcome measures will be compared.

Official Title
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Is Indirect Decompression Sufficient for the Treatment of Central Stenosis?: A Randomized Controlled Trial

Conditions
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Patients With Spinal Stenosis Indicated for LLIF

Intervention / Treatment
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* Procedure: One-level lateral lumbar interbody fusion with Indirect Decompression
* Procedure: One-level lateral lumbar interbody fusion with Direct Decompression


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Fusion indicated by the treating surgeon. Fusion may be indicated for one or more of the following reasons: Mobile degenerative spondylolisthesis Severe vertical foraminal stenosis Adjacent segment degeneration and/or degenerative disc disease with suspected discogenic pain One-level central canal stenosis WITH neurogenic claudication As measured in preoperative MRI Oswestry Low Back Pain Disability Questionnaire score > 35% (18/50) Failed 3 months of conservative treatment Willing to give written informed consent and psychosocially, mentally, and physically able to comply fully with protocol, including adhering to follow-up schedule and requirements, and filling out forms Exclusion Criteria: Multilevel central canal stenosis Patients with vertebral endplate dimensions that are too small to allow for safe placement of an intervertebral cage Known allergy to titanium, polyethylene, cobalt, chromium, or molybdenum Prior surgery at index disc level (discectomy, decompression, or fusion) History of spinal or vertebral infection of the lumbar spine History of vertebral fracture of the lumbar spine Current pregnancy or interest in becoming pregnant over the next 1 year Active infection-systemic or local Non-English speakers

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 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: Parallel Assignment
Interventional Model Description: This is a single-center, prospective, randomized controlled trial.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Group 1: Indirect Decompression<br>Lateral lumbar interbody fusion (LLIF), with indirect decompression | Procedure: One-level lateral lumbar interbody fusion with Indirect Decompression<br>* One-level lateral lumbar interbody fusion, with or without percutaneous posterior instrumentation. Thorough discectomy will be performed using lateral access. Fusion will then be performed using lateral access interbody cage and allograft bone graft with or without use of recombinant human bone morphogenic protein 2.<br>|
| Active Comparator: Group 2: Direct Decompression<br>Lateral lumbar interbody fusion (LLIF), with direct decompression | Procedure: One-level lateral lumbar interbody fusion with Direct Decompression<br>* One-level lateral lumbar interbody fusion, with or without percutaneous posterior instrumentation. Thorough discectomy will be performed using lateral access instruments. Fusion will then be performed using lateral access interbody cage and allograft bone graft with or without use of recombinant human bone morphogenic protein 2. Additionally, direct decompression through midline or parasagittal approach will be utilized. A unilateral laminotomy or complete bilateral laminectomy may be performed.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Oswestry Disability Index (ODI) | Change in Oswestry Disability Index (ODI) 100 point scale. The Oswestry Disability Index (also known as the Oswestry Low Back Pain Disability Questionnaire) is an extremely important tool that researchers and disability evaluators use to measure a patient's permanent functional disability. The test is considered the 'gold standard' of low back functional outcome tools [1]. For each section the total possible score is 5: if the first statement is marked the section score = 0; if the last statement is marked, it = 5. If all 10 sections are completed the score is calculated by adding all scores for each statement, divided by 50 total possible points, and then multiplied by 100 for a percentage. Percentage scores are interpreted on a scale from 0-20% as minimal disability to 61-100% as crippled. | Up to 12 months post-operatively | 
| Comparison of Oswestry Disability Index (ODI) | Compare ODI scores to assess the kinetics of improvement in the control (direct decompression) vs. treatment (indirect decompression) groups. The Oswestry Disability Index (also known as the Oswestry Low Back Pain Disability Questionnaire) is an extremely important tool that researchers and disability evaluators use to measure a patient's permanent functional disability. The test is considered the 'gold standard' of low back functional outcome tools [1]. For each section the total possible score is 5: if the first statement is marked the section score = 0; if the last statement is marked, it = 5. If all 10 sections are completed the score is calculated by adding all scores for each statement, divided by 50 total possible points, and then multiplied by 100 for a percentage. Percentage scores are interpreted on a scale from 0-20% as minimal disability to 61-100% as crippled. | Up to 24 months post-operatively. (6 weeks, 3, 6, 12, and 24 months timepoints) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Reoperation Rate | Reoperation rate on the lumbar spine within 12 months and within 24 months | Within 12 months and 24 months, post-operatively. | 
| Complication Rate | Complication rate within 12 months and within 24 months | Within 12 months and 24 months, post-operatively. | 
| Numeric Rated Scale (NRS)-Back and Leg pain | Patient Reported Outcomes: Numeric Rated Scale (NRS)-back and leg pain scores | 6- Weeks, 3-, 6-, 12-, and 24-Months. | 
| Radiographic Measurements - Lumbar Lordosis | Radiographic measurements at 12 months will be compared to preoperative measurements to quantify the change in lumbar lordosis as a result of Lateral Lumbar Interbody Fusion (LLIF). Measurements will be taken in millimeters by (2) co-investigators. | Preoperative and 12-Month radiographs | 
| Radiographic Measurements - Segmental Lordosis | Radiographic measurements at 12 months will be compared to preoperative measurements to quantify the change in segmental lordosis as a result of Lateral Lumbar Interbody Fusion (LLIF). Measurements will be taken in millimeters by (2) co-investigators. | Preoperative and 12-Month radiographs | 
| Radiographic Measurements - Disc Space Height | Radiographic measurements at 12 months will be compared to preoperative measurements to quantify the change in disc space height as a result of Lateral Lumbar Interbody Fusion (LLIF). Measurements will be taken in millimeters by (2) co-investigators. | Preoperative and 12-Month radiographs | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Lateral Lumbar Interbody Fusion (LLIF), Foraminal Stenosis, Spine Fusion, Decompression, Lumbar