Preventive Effect of Limited Decompression on Adjacent Segment Following Posterior Lumbar Interbody Fusion

Study Overview
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Brief Summary
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This is a prospective single-center study. Patients requiring posterior lumbar interbody fusion (PLIF) for degenerative disease are prospectively enrolled and followed. Patients enrolled in this study have asymptomatic pre-existing spinal canal stenosis at adjacent segment. This study will focus on the effects of preventative limited decompression at adjacent segment.

Detailed Description
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Adjacent segment pathologies (ASP), including radiological adjacent segment degeneration (ASDeg) and adjacent segment disease (ASDis) after lumbar fusion surgeries have been troubling complications. The development of ASDis greatly reduces postoperative quality of life, and revision surgery may be required in severe cases. Several risk factors for ASP have been reported, such as age, sex, pre-existing adjacent degeneration, multilevel fusions, sagittal imbalance, the type of fusion, facet tropism and laminar inclination. Previous studies have reported asymptomatic pre-existing spinal canal stenosis (SCS) as a risk factor for ASDis that requires additional surgery. Appropriate strategy needs to be explored for the treatment of asymptomatic pre-existing spinal canal stenosis. Limited decompressions, including partial laminotomy and flavectomy, have been proved to have the role of enlargement in spinal canal. Therefore, we hypothesize that limited decompressions at adjacent segment with asymptomatic pre-existing SCS will have the preventive effect on ASP. This prospective study will be limited to patients with the same preoperative pathology, the same fusion segments (L4-5 and L5-S1), the same fusion technique (PLIF). Dynamic X-ray and MRI examinations of lumbar will be completed to evaluate the imaging manifestations of the responsible and adjacent segments before surgery. Patients with asymptomatic pre-existing canal stenosis factors (cerebrospinal fluid occlusion grade 1) at L3/4 segment will be enrolled. Patients will be randomly divided into two groups according to different strategies. NS Group includes patients who simply receive responsible segments fused (L4-S1). LD Group includes patients who receive responsible segments fused (L4-S1) plus limited decompression at adjacent segment (L3/4). In terms of limited decompression at the adjacent segment, partial laminotomy, flavectomy, and bilateral medial facetectomies up to the pedicle will be performed. Complete laminectomy and destroy of posterior ligament complex will be avoided. The patient's age, gender, preoperative body mass index (BMI), American Society of Anesthesiologists classification of anesthesia (ASA grade) will be recorded during the hospital stay. Surgical data including operation time, blood loss, perioperative complications (including cerebrospinal fluid leakage, wound infection, postoperative neurological dysfunction, and perioperative secondary surgery, cardiopulmonary complication, cerebral infarction/hemorrhage, etc.), and length of hospital stay are also recorded. Preoperative clinical function questionnaires, including visual analog scale (VAS) of low back, VAS of the legs, and Oswestry Disability Index (ODI) scores for patients were completed on admission for surgery without any assistance. All the patients enrolled will finished the follow-up from date of surgery at 1,2, 5 and 10 years. The clinical outcomes and ASP will be recorded.

Official Title
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Preventive Effect of Limited Decompression on Adjacent Segment With Pre-existing Spinal Canal Stenosis Following Posterior Lumbar Interbody Fusion: a Prospective Interventional Study

Conditions
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Degenerative Lumbar Spinal Stenosis, Degenerative Disc Disease, Degeneration Spine

Intervention / Treatment
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* Procedure: Limited decompressions at adjacent segment with asymptomatic pre-existing spinal canal stenosis
* Procedure: Responsible segments fused


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: A clear diagnosis of lumbar spinal stenosis, and surgical level of L4-S1 (The levels to be operated on were decided by matching the clinical symptomatology with the radiological findings of the spinal levels that needed decompression); Patients have asymptomatic pre-existing spinal canal stenosis (cerebrospinal fluid occlusion grade=1) at adjacent segment. Failed at least eight weeks conservative treatment; Exclusion Criteria: Unstable factors (slip, rotation, lateral bending, etc.) in adjacent segment L3/4; Preoperative sagittal and coronal imbalance of the spine; Lumbar infection and/or tumor diseases; A previous history of lumbar fusion surgery.

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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: NS Group<br>NS Group includes patients who simply receive responsible segments fused (L4-S1). | Procedure: Responsible segments fused<br>* In terms of responsible segments fused, L4-5 and L5-S1 were fused using posterior lumbar interbody fusion (PLIF).<br>|
| Experimental: LD Group<br>LD Group includes patients who receive responsible segments fused (L4-S1) plus limited decompression at adjacent segment (L3/4). | Procedure: Limited decompressions at adjacent segment with asymptomatic pre-existing spinal canal stenosis<br>* In terms of limited decompression at the adjacent segment, partial laminotomy, flavectomy, and bilateral medial facetectomies up to the pedicle will be performed. Complete laminectomy and destroy of posterior ligament complex will be avoided.<br>Procedure: Responsible segments fused<br>* In terms of responsible segments fused, L4-5 and L5-S1 were fused using posterior lumbar interbody fusion (PLIF).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Adjacent segment degeneration | ASDeg is defined as follows according to manifestations on X-rays and MRI changing from baseline : (1) Progression ≥1 grade in SCS or L3/4 disc degeneration; (2)Alteration of L3/4 disc herniation, Hiz and vacuum sign; (3) Progression of ≥ 3 mm in vertebral slippage, a change of ≥ 10° in the intervertebral angle on flexion and extension lateral radiograph, or scoliosis deformity on coronal plane. | 12 months after surgery | 
| Adjacent segment degeneration | ASDeg is defined as follows according to manifestations on X-rays and MRI changing from baseline : (1) Progression ≥1 grade in SCS or L3/4 disc degeneration; (2)Alteration of L3/4 disc herniation, Hiz and vacuum sign; (3) Progression of ≥ 3 mm in vertebral slippage, a change of ≥ 10° in the intervertebral angle on flexion and extension lateral radiograph, or scoliosis deformity on coronal plane. | 24 months after surgery | 
| Adjacent segment degeneration | ASDeg is defined as follows according to manifestations on X-rays and MRI changing from baseline : (1) Progression ≥1 grade in SCS or L3/4 disc degeneration; (2)Alteration of L3/4 disc herniation, Hiz and vacuum sign; (3) Progression of ≥ 3 mm in vertebral slippage, a change of ≥ 10° in the intervertebral angle on flexion and extension lateral radiograph, or scoliosis deformity on coronal plane. | 60 months after surgery | 
| Adjacent segment degeneration | ASDeg is defined as follows according to manifestations on X-rays and MRI changing from baseline : (1) Progression ≥1 grade in SCS or L3/4 disc degeneration; (2)Alteration of L3/4 disc herniation, Hiz and vacuum sign; (3) Progression of ≥ 3 mm in vertebral slippage, a change of ≥ 10° in the intervertebral angle on flexion and extension lateral radiograph, or scoliosis deformity on coronal plane. | 120 months after surgery | 
| Adjacent segment disease | ASDis is defined as clinical and radiographic evidence of degenerative spinal disease (disc degeneration, stenosis, or spondylolisthesis) on the level adjacent to the index fusion. | The entire study process, up to 120 months after surgery. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Disability | The Oswestry Disability Index (ODI) (0-100) is used to assess disability. | 12 months after surgery; 24 months after surgery; 60 months after surgery; 120 months after surgery. | 
| Back pain | The Visual Analog Scale (0-10) is used to evaluate back pain. | 12 months after surgery; 24 months after surgery; 60 months after surgery; 120 months after surgery. | 
| Leg pain | The Visual Analog Scale (0-10) is used to evaluate leg pain. | 12 months after surgery; 24 months after surgery; 60 months after surgery; 120 months after surgery. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Adjacent segment degeneration, Adjacent segment disease, Pre-existing degeneration, Limited decompression