TOPS System

The total posterior spine or TOPS system is an FDA-approved mechanical implant that serves as an alternative to lumbar interbody fusion surgery after decompression. It was developed by Impliant and commercially launched by Premia Spine.

The TOPS System offers new methods for the non-fusion treatment of degenerative spondylolisthesis and spinal stenosis.

Uses
It treats patients diagnosed with common degenerative spinal diseases such as lumbar spinal stenosis, which occurs when the small joints between the vertebrae compress the spinal nerve roots in the lower back and Grade 1 spondylolisthesis occurs when one vertebra "slips" over the one below it. One of the differences between the TOPS System and traditional fusion surgery is that the TOPS device allows the patient physical stability and a greater range of movement in all directions.

Surgical procedure
The TOPS System is a unitary implant composed of two titanium plates connected by an interlocking flexible articulating core. It has metal arms connecting horizontally to pedicles with four polyaxial screws. The device can be implanted after a standard decompression by removing the lamina and medial facets in a "posterior arthroplasty" procedure. The TOPS System replaces the bony and soft tissue removed during spinal decompression surgery and implants them at the affected spine segment to aid the patient's flexibility.

History
Premia Spine developed the TOPS System and initiated a US trial to compare it with the traditional transforaminal lumbar interbody fusion (TLIF) procedure. Results showed that the TOPS System offers significant clinical, health, and societal benefits over TLIF. Under the Investigational Device Exemption (IDE) study by the FDA, the system was available to a limited number of U.S. patients at select hospitals and institutions.

In March 2021, the U.S. Food and Drug Administration (FDA) granted a “breakthrough device designation” (FDA’s initiative for medical devices that significantly improve treatment of severe or debilitating conditions) to the TOPS System.

In 2023, the U.S. Food and Drug Administration approved the TOPS System as an implant designed to stabilize the lower spine and maintain the range of motion after surgery to relieve compressed nerves (lumbar decompression surgery).

Research
Studies highlighted its ability to preserve spine biomechanics, measuring effects on disc strain and bulge. Pain and quality of life improvements were quantitatively assessed using the Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and Short Form 36 (SF-36). X-rays, CT scans, and MRIs were used to monitor the implant for adverse events or changes.

A 2012 study presented in Barcelona found that one in four elderly patients who had lumbar spinal fusion for lumbar spinal stenosis (LSS) or spondylolisthesis needed a second spinal surgery within two years. Additionally, nearly half of these patients were readmitted to the hospital due to complications. Comparatively, Premia Spine's follow-ups over five years in Belgium and Israel suggest that the TOPS System yields significantly better outcomes, with a preoperative complication rate under five percent.

In March 2021, Premia Spine received FDA breakthrough device designation for its Tops facet arthroplasty system.

In July 2021, Jared Ament presented the clinical and economic evidence supporting the TOPS facet arthroplasty system at the Spine Summit, San Diego, demonstrating its cost-effectiveness compared to TLIF for treating spondylolisthesis and spinal stenosis.

In November 2021, its intermediate clinical study results, presented at the Society for Minimally Invasive Spine Surgery (SMISS) supported the use of the TOPS System for lumbar spinal stenosis and degenerative spondylolisthesis.

In June 2022, a study published in the Journal of Health Economics and Outcomes Research demonstrated that the TOPS System offers significant health and societal benefits compared to TLIF in treating degenerative spondylolisthesis and stenosis.

In September 2022, the journal Operative Neurosurgery published a single-center study evaluating its TOPS System for lumbar spinal stenosis and degenerative spondylolisthesis. The paper "Mobility-Maintaining Arthroplasty of the Lumbar Spine with the Second-Generation TOPS System" by Werner Lack, Hans Paul Kutschera, and Josef Krugluge found that the TOPS facet replacement can relieve leg and back pain while maintaining nearly normal range-of-motion for four years without causing adjacent segment disease. The study also noted that the TOPS System uniquely helps patients maintain natural sagittal balance, offering new options for non-fusion treatment of degenerative spondylolisthesis and spinal stenosis.

FDA Approval Study
Premia Spine received FDA approval to start an IDE trial of the TOPS System with 300 to 500 patients across up to 40 U.S. centers, randomizing participants into TOPS (67%) or fusion (33%) arms. The trial aims to compare the efficacy of TOPS versus TLIF in stabilizing one lumbar level (L2-L5) after decompression in patients with moderate lumbar spinal stenosis and Grade 1 spondylolisthesis, including conditions like thickened ligamentum flavum or scarred facet joints.

In September 2022, Dr. Dom Coric and colleagues published a study in the Journal of Neurosurgery Spine, which demonstrated that the TOPS System, a motion-preserving treatment for lumbar stenosis with degenerative spondylolisthesis, outperformed TLIF in clinical success rates.

The FDA concluded, as part of its PMA approval process and commercial release of the TOPS System, that the TOPS group demonstrated a clinically meaningful and substantial advantage over the Fusion control group, with 77% of subjects randomized to the TOPs group achieving composite clinical success, compared to 24% of subjects randomized to the fusion control. Based on these results, the TOPS System was deemed to be superior to the Fusion control with respect to composite clinical success while maintaining equivalent safety.