Study Evaluating the Safety and Effectiveness of the FLEXUS(TM) Interspinous Spacer

Study Overview
=================
Brief Summary
-----------------
The purpose of this investigation is to evaluate the safety and effectiveness of the FLEXUS™ Interspinous Spacer as compared to the XSTOP® Spacer for the treatment of patients who are suffering from lumbar spinal stenosis at one or two contiguous levels.

Official Title
-----------------
A Prospective Randomized Clinical Investigation of the FLEXUS(TM) Interspinous Spacer: A Pivotal Study

Conditions
-----------------
Lumbar Spinal Stenosis

Intervention / Treatment
-----------------
* Device: FLEXUS(TM) Interspinous Spacer
* Device: XSTOP® Interspinous Spacer


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Lumbar spinal stenosis as defined by leg, buttock or groin pain, with or without back pain, that relieves during flexion, with radiographic confirmation of spinal stenosis by CT or MRI scans at one or two contiguous levels between L1 and S1. If back pain is also present, it must be partially relieved during flexion Narrowing of the spinal canal, nerve root canal or intervertebral foramen at one or two levels Able to sit for 50 minutes without pain Able to walk 50 feet or more Age 50 years or over Has completed at least 6 months of conservative treatment Has a Zurich Claudication Questionnaire (ZCQ) score of ≥ 1.5 for Physical Function (PF) and ≥ 1.5 for Symptom Severity (SS) Other as specified in the approved protocol Exclusion Criteria: Cannot sit for 50 minutes without pain Cannot walk for more than 50 feet Unremitting pain in any spinal position Axial back pain only without leg, buttock, or groin pain Fixed motor deficit Cauda equine syndrome, defined as neural compression causing neurogenic bowel (rectal incontinence) or bladder (bladder retension or incontinence) dysfunction Severe symptomatic lumbar spinal stenosis at more than two levels Significant instability of the lumbar spine Has had any surgery of the lumbar spine Morbid obesity defined as a body mass index >40 or a weight more than 100 lbs over ideal body weight Active systemic disease such as AIDS, HIV, Hepatitis, etc. Active systemic or local infection Angina, active rheumatoid arthritis, advanced diabetes or any other systemic disease that would affect the subject's welfare or outcome of the study Osteoporosis, defined as DEXA bone density measured T-score < -2.5 Spinal metastasis to the vertebrae Known allergy to device materials titanium, tantalum, or polyetheretherketone (PEEK) polymer Other as specified in approved protocol

Ages Eligible for Study
-----------------
Minimum Age: 50 Years

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

Accepts Healthy Volunteers
-----------------
No

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

Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: FLEXUS™ Interspinous Spacer<br> | Device: FLEXUS(TM) Interspinous Spacer<br>* Treatment of lumbar spinal stenosis with the FLEXUS™ Interspinous Spacer<br>|
| Active Comparator: XSTOP® Interspinous Spacer<br> | Device: XSTOP® Interspinous Spacer<br>* Treatment of lumbar spinal stenosis with the XSTOP® Spacer<br>|

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

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants With Less Pain/Disability Using the Zurich Claudication Questionnaire (ZCQ) Score | Change in the Zurich Claudication Questionnaire (ZCQ) score at 24 months compared with the score at baseline as follows: Change of >0.5 points in Physical Function on a scale of 1-4 points (lower values are considered a better outcome) Change of >0.5 points in Symptom Severity on a scale of 1-5 points (lower values are considered a better outcome) Satisfaction of <2.5 points on a scale of 1-4 points (lower values are considered a better outcome) The Zurich Claudication Questionnaire is a three part form that quantifies severity of symptoms, physical function characteristics, and patient's satisfaction after treatment. | 24 months | 
| Number of Participants With a Successful Neurologic Status | Neurological status is based on four types of measurement parameters: motor, sensory, reflexes, and special assessments. Each parameter will be coded as follows: Motor 0 Total Paralysis Palpable or Visible Contraction Active Movement, Gravity Eliminated Active Movement, Against Gravity Active Movement, Against Some Resistance Active Movement, Against Full Resistance Sensory 0 Absent Impaired Normal Reflexes 0 Absent or Trace Hyper-reflexic Normal or hypo-reflexic Straight Leg Raise 0 0°-70° (abnormal) 1 >70°-90° (normal) If all evaluations for the parameter are determined to be normal, then the parameter is given a normal status. If any evaluations for the parameter are abnormal, then the parameter is given an abnormal status. The overall neurological status will be considered a success if and only if all the four parameters are stable or improved. | 24 months | 
| Number of Participants With no Additional Surgery for Lumbar Spinal Stenosis at the Spinal Level That Was Treated | Measures the number of participants who did not have another surgery for treatment of lumbar spinal stenosis at the same spinal level that was originally treated. Data, including adverse events, were monitored, evaluated and assessed for evidence of additional surgical treatment at the spinal level that was originally treated. | 24 months | 
| Number of Participants With an Absence of Implant-related Complications | Absence of implant-related complications, including device dislodgement, defined as: Failure of implant material (e.g. fracture); Implant migration outside of the interspinous space (posteriorly beyond the posterior margin of the spinous processes, anteriorly within the spinal canal, or laterally more than half of the implant width); or Other complications that can be specifically associated with the implanted device. | 24 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean Oswestry Disability Index (ODI) at 24 Months | The Oswestry Disability Index (ODI) questionnaire contains ten topics concerning intensity of pain, lifting, ability to care for oneself, ability to walk, ability to sit, sexual function, ability to stand, social life, sleep quality, and ability to travel. Each topic is followed by 6 statements describing different potential scenarios in the patient's life relating to the topic. The subject chooses the statement which most closely resembles their situation. Each question is scored on a scale of 0-5 with the first statement being zero and indicating the least amount of disability and the last statement is scored 5 indicating most severe disability. Scores for all questions answered are summed, then multiplied by two to obtain the index (range 0 to 100). Zero is equated with no disability and 100 is the maximum disability. | 24 months | 
| Mean Visual Analog Scale (VAS) - Back Pain at 24 Months | The visual analog scale (VAS) is a questionnaire used to quantify a subjective experience, such as the intensity of pain. The scale is a 100mm line labeled with no pain on the left border and as severe as it could be on the right border. The subject is instructed to make a mark along the line to represent the intensity of back pain currently being experienced; 0mm is equal to no pain and 100mm is pain as severe as it could be. The clinician records the distance of the mark in millimeters from the left end of the scale. | 24 months | 
| Mean Visual Analog Scale (VAS) - Right Leg Pain at 24 Months | The visual analog scale (VAS) is a questionnaire used to quantify a subjective experience, such as the intensity of pain. The scale is a 100mm line labeled with no pain on the left border and as severe as it could be on the right border. The subject is instructed to make a mark along the line to represent the intensity of right leg pain currently being experienced; 0mm is equal to no pain and 100mm is pain as severe as it could be. The clinician records the distance of the mark in millimeters from the left end of the scale. | 24 months | 
| Mean Visual Analog Scale (VAS) - Left Leg Pain at 24 Months | The visual analog scale (VAS) is a questionnaire used to quantify a subjective experience, such as the intensity of pain. The scale is a 100mm line labeled with no pain on the left border and as severe as it could be on the right border. The subject is instructed to make a mark along the line to represent the intensity of left leg pain currently being experienced; 0mm is equal to no pain and 100mm is pain as severe as it could be. The clinician records the distance of the mark in millimeters from the left end of the scale. | 24 months | 
| Change of Quality of Life | Change in mental or physical composite score of the short form SF36 | 24 months | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Back pain, Pain, Spinal Diseases, Spinal Stenosis, Lumbar Vertebrae, Spinal Canal