Don't get left behind! The modernized is coming. Check it out now.
Say goodbye to!
The new site is coming soon - go to the modernized
Working… Menu

Safety and Effectiveness Study of the TOPS System, a Total Posterior Arthroplasty Implant Designed to Alleviate Pain Resulting From Moderate to Severe Lumbar Stenosis

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00405691
Recruitment Status : Completed
First Posted : November 30, 2006
Last Update Posted : May 18, 2011
Information provided by:
Impliant, Ltd.

Brief Summary:
The purpose of this multi-center, randomized, clinical study is to establish the safety and effectiveness of the TOPS™ System, used following decompression, in the treatment of lower back and leg pain with, or without spinal claudication, that results from moderate or severe lumbar spinal stenosis at one vertebral level between L3 and L5.

Condition or disease Intervention/treatment Phase
Low Back Pain Leg Pain Spondylolisthesis Lumbar Spinal Stenosis Device: "TOPS System" - Total Posterior Arthroplasty Implant Phase 3

Detailed Description:

This study is being conducted to evaluate a new surgical implant (TOPS™ System, Impliant). The TOPS™ System is an alternative to spinal fusion that is designed to stabilize but not fuse the affected vertebral level following decompression surgery to alleviate pain stemming from moderate/severe lumbar spinal stenosis while maintaining range of motion.

When non-surgical treatment is ineffective, decompression (including laminectomy and medial facetectomy) and fusion of the spinal segments with moderate/severe lumbar spinal stenosis has been used to stabilize the motion segment and to alleviate the patient's clinical symptoms. Spinal fusion surgery using metal instrumentation is designed to stop motion at a painful, unstable spinal segment by permanently fusing the segment. While fusion may decrease pain generated at the treated segment, the procedure also eliminate motion at the implanted level and transfers and thus increases loads on the adjacent segments.

The TOPS System is intended to provide stabilization following decompression in patients with disease at one level from L3 to L5. The ideal goal of stabilization is to preserve mobility but eliminate abnormal motion and prevent deformity. By using the TOPS System, it may be possible to preserve load-bearing dynamics and spinal biomechanics, and thereby maintaining motion at the treated segment.

The TOPS surgical technique, utilizing a standard top loading pedicle screw-based system, is the same as a standard posterior spinal fusion with the exception of the placement of the TOPS motion segment. Therefore, the surgeon will be executing the steps of surgical exposure, decompression, insertion of pedicle screws (with attention to proper placement/alignment) and closure in the same manner as he/she would in a standard posterior spinal fusion.

The objective of the clinical investigation is to compare the safety and effectiveness of the TOPS System to a control group of patients undergoing posterior spinal fusion with pedicle screws and local autograft bone in the treatment of back and leg pain that results from moderate/severe lumbar spinal stenosis at a single vertebral level between L3 to L5.

Prior to entering the study, patients will be evaluated by the investigator according to the inclusion/exclusion criteria. Patients recruited to the study will be randomized in a 1:1 ratio to undergo implantation of the TOPS System or the control spinal fusion procedure. Patient follow-up will be evaluated immediately post-operatively and at discharge, 6 weeks, 3 months, 6 months, 12 months, and 24 months.

Layout table for study information
Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 450 participants
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: Single (Participant)
Primary Purpose: Treatment
Official Title: A Prospective, Multi-Center Clinical Study to Assess the Saftey and Effectiveness of the Impliant TOPS System
Study Start Date : September 2006

Primary Outcome Measures :
  1. Primary safety and effectiveness to determine patient success are: 1 .15% ODI improvement vs baseline at 24 mos; 20 mm leg and back pain VAS improvement vs baseline at 24 mos.
  2. 2. improvement of at least 20 mm in leg pain at 24 months compared to baseline using a VAS pain scale;
  3. 3. maintenance or improvement of neurological status;
  4. 4. no revisions, supplemental fixation, and removals;
  5. 5. absence of major device-related complications (device component degradation or breakage, device component separation or disassembly, device component loosening (including screw loosening)) requiring revisions, supplemental fixation, and removals;
  6. 6. absence of spontaneous fusion in the investigational group and lack of fusion in the control

Secondary Outcome Measures :
  1. Secondary outcome measurements that will be assessed include: 1. Zurich Claudication Questionaire scores, SF-36 scores, and VAS back pain score
  2. 2. Adverse events
  3. 3. time to recovery, work status, OR time, blood loss, and pharmaceutical use
  4. 4. radiographic measurements (degree of stenosis & spondylolisthesis, disc height, disc angle, alignment, translational motions, Range of Motion (affected level and entire lumbar spine), disc health (affected & adjacent levels), fusion status.

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

Layout table for eligibility information
Ages Eligible for Study:   40 Years to 75 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes


  • Moderate to Severe lumbar spinal stenosis at a single level* between L3 - L5, with radiographic confirmation of any one of the following on CT, MRI, plain x-ray or myelography:

    • Evidence of thecal sac and/or cauda equina compression
    • Evidence of nerve root impingement by either osseous or non-osseous elements;
    • Evidence of hypertrophic facets with canal encroachment Moderate/severe spinal stenosis is further defined radiographically as;
    • moderate canal stenosis is a 25-49% reduction in the A/P dimension of the central and/or lateral foramen when compared to adjacent (cephlad) level
    • Severe canal stenosis is defined as 50% or greater reduction in the A/P dimension of the central and/or lateral foramen when compared to the adjacent (cephlad) level **Patients which require minimal decompressive surgery at an adjacent level, may have a laminonotmy or soft tissue resection as long as the decompression does not compromise the stability of the adjacent segment.
  • At least six (6) months of failed, conservative treatment prior to surgery, including physical therapy, use of anti-inflammatory medications at maximum specified dosage; administration of epidural/facet injections.
  • Age 40-75 years old (male or female).
  • Up to one prior surgery without instrumentation implanted at any lumbar vertebral level limited to the following:

    • IDET,
    • laminotomy,
    • laminectomy,
    • foraminotomy
    • Discectomy (that occurred at least three years ago without any reoccurrence of herniation)
  • Lower back pain and/or sciatica with or without spinal claudication.
  • VAS leg pain of at least 40/100 at baseline.
  • Oswestry Questionnaire score of at least 40/100 at baseline.


  • Back or non-radicular leg pain of unknown etiology
  • Spondylolisthesis Grade II or higher
  • Stenosis caused by an extruded spinal disc fragment
  • Lytic spondylolisthesis
  • More than one (1) motion segment involved in the degenerative pathology to the extent that justifies its inclusion in the surgical procedure, unless a decompression alone can be done at that level without compromising stability.
  • Known allergy to titanium and/or polyurethane
  • Prior fusion surgery at any lumbar vertebral level with or without instrumentation
  • Supplemental interbody support required (e.g., bone graft, spacers, VBRs, or fusion cages)
  • Clinically compromised vertebral bodies at the affected level(s) due to any traumatic, neoplastic, metabolic or infectious pathology.
  • Scoliosis of greater than ten (10) degrees (both angular and rotational)
  • Morbid obesity defined as a body mass index > 40 or a weight more than 100 lbs. over ideal body weight.

Note: Additional inclusion/exclusion criteria are applied. Please contact Impliant for further details.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00405691

Layout table for location information
United States, California
Institute for Advanced Spinal Research In California
Beverly Hills, California, United States, 90211
Century City Doctors Hospital
Beverly Hills, California, United States, 90212
Seton Medical Center
Daly City, California, United States, 94015
United States, Connecticut
Yale University - School of Medicine
New Haven, Connecticut, United States, 06519
The Orthopaedic & Sports Medicine Ctr.
Trumbull, Connecticut, United States, 06611
United States, Florida
Florida Orthopaedic Institute
Tampa, Florida, United States, 33637
United States, Illinois
Illinois Neuro Spine Center
Ogden, Illinois, United States, 60504
United States, Maryland
Saint Joseph Medical Center & Orthopaedic Associates
Baltimore, Maryland, United States, 21204
United States, Massachusetts
The Boston Spine Group
Boston, Massachusetts, United States, 02120
New England Neuro Assoc.
Springfiled, Massachusetts, United States, 01104
United States, Missouri
Columbia Orthopedic Group
Columbia, Missouri, United States, 65201
United States, New York
Orthopedic Spine Care of Long Island
Huntington Station, New York, United States, 11746
Buffalo Spine Surgery
Lockport, New York, United States, 14094
United States, North Carolina
Carolinas Medical Center Hospital - Neurosurgery & Spine Associates
Charlotte, North Carolina, United States, 28204
United States, Wisconsin
NeuroSpine Center of Wisconsin
Appleton, Wisconsin, United States, 54913
Milwaukee Spinal Specialists
Milwaukee, Wisconsin, United States, 53211
Sponsors and Collaborators
Impliant, Ltd.
Layout table for investigator information
Principal Investigator: Paul McAfee, M.D. Orthopaedic Associates, P.A
Layout table for additonal information
Responsible Party: Dan Finan, Impliant, Inc. Identifier: NCT00405691    
Other Study ID Numbers: TOPS-US-IDE-002
First Posted: November 30, 2006    Key Record Dates
Last Update Posted: May 18, 2011
Last Verified: January 2010
Keywords provided by Impliant, Ltd.:
Medical Device
Lumbar Spinal Stenosis
Degenerative Spondylolisthesis
Facet Arthrosis
Back and Leg Pain
Spine Research
Medical Device Research
Lumbar Treatment
Spinal Treatment
Spinal Device
Additional relevant MeSH terms:
Layout table for MeSH terms
Spinal Stenosis
Low Back Pain
Constriction, Pathologic
Back Pain
Neurologic Manifestations
Pathological Conditions, Anatomical
Spinal Diseases
Bone Diseases
Musculoskeletal Diseases