Decompression Versus Decompression and Fusion

Study Overview
=================
Brief Summary
-----------------
Adjacent segment disease (ASD) in the lumbar spine is a well-known sequela of lumbar fusion surgery. The annual incidence of adjacent level re-operation is approximately 3% with a ten-year prevalence of 20-30%. Frequently, the surgical treatment involves decompression of the adjacent level coupled with extension of the instrumentation and fusion. Advocates of this paradigm cite the altered kinematics and biomechanics of levels adjacent to a lumbar fusion mass. Furthermore, decompressed levels adjacent to a fused segments are associated with higher rates of ASD in retrospective studies. Yet, a retrospective review of higher quality data concluded decompression adjacent to single-level fusion provides similar outcomes compared to fusions extending across the decompressed segments. Given the conflicting data currently available, higher quality data are needed to guide surgical decision-making in ASD. The purpose of this trial is to prospectively compare decompression and decompression with fusion in patients with lumbar ASD.

Official Title
-----------------
Decompression Versus Decompression and Fusion for Lumbar Adjacent Segment Disease

Conditions
-----------------
Adjacent Segment Disease

Intervention / Treatment
-----------------
* Procedure: Randomized: Decompression
* Procedure: Randomized: Extension Fusion
* Procedure: Observational: Decompression
* Procedure: Observational: Extension Fusion


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Adult patients at least one year removed from a previous instrumented posterior lumbar fusion Patients with any prior posterior fusion involving L2 to the sacrum, whether single-level or multilevel Patients with symptoms related to central and lateral recess at the supradjacent level that have persisted despite at least six weeks of non-operative therapy modalities Exclusion Criteria: Patients with previous uninstrumented lumbar fusions Patients with traumatic, neoplastic, or infectious etiologies at the adjacent segment Patients with prior iliac or sacroiliac fixation and those with nonunion as the primary indication for surgery Patients with pre-existing instability at the supradjacent level. The definition of instability will be determined based on standing lateral, flexion and extension plain radiographs. Patients with >3mm of change between these views will be excluded. Retrolisthesis will not be a criterion for exclusion

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Patients will be identified for inclusion by surgeons who are co-investigators in this trial. All eligible patients will be submitted to the study coordinator and randomized (if no surgical preference) to a surgical treatment cohort (exposure) regardless of their enrollment status to capture the eligibility to enrollment ratio. Randomization will be performed in random permuted blocks of 4 within strata. One stratum will be prior single level lumbar fusion or multilevel fusions. This randomization technique was selected given the relatively low sample size (N<1000) and concern for unbalanced cohorts arising in relation to prior number of levels fused. The study coordinator will secondarily confirm eligibility of those enrolled. Baseline demographic (age, sex, ethnicity), clinical (BMI, Charlson co-morbidity index, number and levels fused prior), and radiographic data (disc height, disc angle, facet angle) will be collected in a standardized fashion on all patients.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Randomized: Decompression<br> | Procedure: Randomized: Decompression<br>* Patients will undergo decompression alone of the supradjacent level. The surgical technique will be surgeon dependent. All surgeons will be encouraged to avoid damaging facet joints above the fusion mass, retaining 50% of the pars of the decompressed level and performing as minimal of a medial facetectomy as necessary.<br>|
| Active Comparator: Randomized: Extension Fusion<br> | Procedure: Randomized: Extension Fusion<br>* Patients will undergo decompression and extension of posterior instrumentation and fusion. This may or may not include exchange of pre-existing instrumentation. The use of interbody cages will be left to the discretion of the treating surgeon. The purpose of introducing this heterogeneity is to increase the generalizability of the trial results. The fusion cohort will not utilize bone morphogenetic protein products.<br>|
| Experimental: Observational: Decompression<br>Eligible patients may have a preference for the surgical procedure they wish to have. In these instances, they may choose to undergo a decompression alone or a decompression with extension of fusion. These patients are still eligible for the study and may be enrolled under observational arms. This arm refers to the decompression alone observational study arm. All study procedures are identical to the randomized decompression alone study arm. | Procedure: Observational: Decompression<br>* This intervention is identical to the Randomized: Decompression intervention. Patients will undergo decompression alone of the supradjacent level. The surgical technique will be surgeon dependent. All surgeons will be encouraged to avoid damaging facet joints above the fusion mass, retaining 50% of the pars of the decompressed level and performing as minimal of a medial facetectomy as necessary.<br>|
| Active Comparator: Observational: Extension Fusion<br>Eligible patients may have a preference for the surgical procedure they wish to have. In these instances, they may choose to undergo a decompression alone or a decompression with extension of fusion. These patients are still eligible for the study and may be enrolled under observational arms. This arm refers to the decompression with extension of fusion study arm. All study procedures are identical to the randomized decompression with extension of fusion study arm. | Procedure: Observational: Extension Fusion<br>* This intervention is identical to the Randomized: Extension Fusion intervention. Patients will undergo decompression and extension of posterior instrumentation and fusion. This may or may not include exchange of pre-existing instrumentation. The use of interbody cages will be left to the discretion of the treating surgeon. The purpose of introducing this heterogeneity is to increase the generalizability of the trial results. The fusion cohort will not utilize bone morphogenetic protein products.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Global Health, Physical | Scored by Patient-Reported Outcomes Measurement Information System (PROMIS): 16-68 (higher score = better outcome) | 3 months, 6 months, 1 year, and 2 years post-operation | 
| Physical Function, short form 10a (SF10a) | Scored by Patient-Reported Outcomes Measurement Information System (PROMIS): 0-62 (higher score = better outcome) | 3 months, 6 months, 1 year, and 2 years post-operation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Global Health, Mental | Scored by Patient-Reported Outcomes Measurement Information System (PROMIS): 21-68 (higher score = better outcome) | 3 months, 6 months, 1 year, and 2 years post-operation | 
| Pain intensity, short form 3a (SF3a) | Scored by Patient-Reported Outcomes Measurement Information System (PROMIS): 30-72 (higher score = better outcome) | 3 months, 6 months, 1 year, and 2 years post-operation | 
| Anxiety, short form 4a (SF4a) | Scored by Patient-Reported Outcomes Measurement Information System (PROMIS): 40-82 (higher score = better outcome) | 3 months, 6 months, 1 year, and 2 years post-operation | 
| Depression, short form 4a (SF4a) | Scored by Patient-Reported Outcomes Measurement Information System (PROMIS): 41-80 (higher score = better outcome) | 3 months, 6 months, 1 year, and 2 years post-operation | 
| Pain interference, short form 4a (SF4a) | Scored by Patient-Reported Outcomes Measurement Information System (PROMIS): 41-76 (higher score = better outcome) | 3 months, 6 months, 1 year, and 2 years post-operation | 
| Post-operative complication | Scored by Clavien-Dindo classification (Grade I, II, IIIa, IIIb, IVa, IVb, and V) defined at https://www.assessurgery.com/clavien-dindo-classification/ | 3 months, 6 months, 1 year, and 2 years post-operation | 
| Hospital length of stay | Scored by how long the patient is in the hospital after operation. | 3 months, 6 months, 1 year, and 2 years post-operation | 
| Post-operative narcotic utilization | Scored by morphine milligram equivalents (MME) over 90 days | 3 months, 6 months, 1 year, and 2 years post-operation |