# TOPS System
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thumb|TOPS Implant attached to a spine model
The '''TOPS System''' (Total Posterior Spine System) is a spinal implant designed to stabilize the lower spine and maintain range of motion following lumbar decompression surgery for [spinal stenosis](/source/lumbar_spinal_stenosis) and related conditions. Unlike [spinal fusion](/source/spinal_fusion), which eliminates motion at the treated level, TOPS aims to preserve mobility while providing stability. The device is manufactured by Premia Spine and has received approval for clinical use in the United States by the [Food and Drug Administration](/source/Food_and_Drug_Administration) (FDA) and in the European Union under the CE (Conformité Européenne) marking.[{{cite web |date=16 June 2023 |title=TOPS System – P220002 |url=https://www.fda.gov/medical-devices/recently-approved-devices/tops-system-p220002 |access-date=29 September 2025 |website=U.S. Food and Drug Administration}}]
== Design and mechanism ==
The device consists of two titanium plates connected by a mechanical articulating core. The plates are fixed to the vertebrae using pedicle screws, while the core allows controlled motion in flexion, extension, lateral bending, and axial rotation. This design provides stability against shear forces while permitting physiological movement of the operated segment.[{{cite journal |last1=Wilke |first1=H J |last2=Schmidt |first2=H |last3=Werner |first3=K |last4=Schmölz |first4=W |last5=Drumm |first5=J |title=Biomechanical evaluation of a new total posterior-element replacement system |journal=Spine |year=2006 |volume=31 |issue=24 |pages=2790–2796 |doi=10.1097/01.brs.0000245872.45554.c0 |pmid=17108830}}]
== Surgical procedure ==
TOPS is implanted following a lumbar decompression, in which bone and ligament tissue compressing the spinal nerves are removed. After decompression, the facet joints are excised and replaced with the TOPS implant. The goal is to preserve mobility at the treated level while preventing instability that would otherwise be addressed with spinal fusion.
== Clinical indications ==
TOPS is generally indicated for patients with lumbar spinal stenosis, with or without grade I [spondylolisthesis](/source/spondylolisthesis). Higher-grade instability is usually treated with spinal fusion rather than motion-preserving devices.[{{cite journal |last1=Nassr |first1=Ahmad |last2=Coric |first2=Domagoj |last3=Pinter |first3=Zachariah W |last4=Sebastian |first4=Arjun S |last5=Freedman |first5=Brett A |last6=Whiting |first6=Donald |last7=Chahlavi |first7=Ali |last8=Pirris |first8=Stephen |last9=Phan |first9=Nicolas |last10=Meyer |first10=Scott A |last11=Tahernia |first11=A David |last12=Sandhu |first12=Faheem |last13=Deutsch |first13=Harel |last14=Potts |first14=Eric A |last15=Cheng |first15=Joseph |last16=Chi |first16=John H |last17=Groff |first17=Michael |last18=Anekstein |first18=Yoram |last19=Steinmetz |first19=Michael P |last20=Welch |first20=William C |title=Lumbar Facet Arthroplasty Versus Fusion for Grade-I Degenerative Spondylolisthesis with Stenosis: A Prospective Randomized Controlled Trial |journal=Journal of Bone & Joint Surgery |year=2024 |volume=106 |issue=12 |pages=1041–1053 |doi=10.2106/JBJS.23.00719 |pmid=38713762 |pmc=11593996}}][{{cite journal |last1=Coric |first1=Domagoj |last2=Nassr |first2=Ahmad |last3=Kim |first3=Paul K |last4=Welch |first4=William C |last5=Robbins |first5=Stephen |last6=DeLuca |first6=Steven |last7=Whiting |first7=Donald |last8=Chahlavi |first8=Ali |last9=Pirris |first9=Stephen M |last10=Groff |first10=Michael W |last11=Chi |first11=John H |last12=Huang |first12=Jason H |last13=Kent |first13=Roland |last14=Whitmore |first14=Robert G |last15=Meyer |first15=Scott A |last16=Arnold |first16=Paul M |last17=Patel |first17=Ashvin I |last18=Orr |first18=R Douglas |last19=Krishnaney |first19=Ajit |last20=Boltes |first20=Peggy |last21=Anekstein |first21=Yoram |last22=Steinmetz |first22=Michael P |title=Prospective, randomized controlled multicenter study of posterior lumbar facet arthroplasty for the treatment of spondylolisthesis |journal=Journal of Neurosurgery: Spine |year=2022 |volume=38 |issue=1 |pages=115–125 |doi=10.3171/2022.7.SPINE22536 |pmid=36152329}}]
== Regulatory history ==
The device was evaluated under an [investigational device exemption](/source/investigational_device_exemption) in the United States, where it was compared against transforaminal lumbar interbody fusion. It was later granted FDA Breakthrough Device designation in 2021,[{{cite web |last=Kirsh |first=D |title=Premia Spine wins FDA breakthrough designation for spinal arthroplasty system |url=https://www.massdevice.com/premia-spine-wins-fda-breakthrough-designation-for-spinal-arthroplasty-system/ |website=MassDevice |date=31 March 2021 |access-date=29 September 2025}}][{{cite web |date=1 April 2021 |title=Premia Spine gets FDA breakthrough device status for TOPS spinal arthroplasty system |url=https://www.nsmedicaldevices.com/company-news/premia-spine-tops/ |access-date=29 September 2025 |website=NS Medical Devices}}] followed by full FDA approval in 2023 after demonstrating superiority over fusion in composite clinical success.[{{cite web |date=16 June 2023 |title=TOPS System – P220002 |url=https://www.fda.gov/medical-devices/recently-approved-devices/tops-system-p220002 |access-date=29 September 2025 |website=U.S. Food and Drug Administration}}] The TOPS System also holds CE marking, signifying that it meets health, safety, and environmental requirements for sale in the [European Economic Area](/source/European_Economic_Area).
== Clinical evidence ==
=== Development and rationale ===
The TOPS System was developed in the early 2000s, with the concept of facet joint replacement introduced by biomedical engineer Uri Arnin.[{{cite web
|title=Premia Spine's bid to solve lumbar spine's motion-stability challenge
|url=https://www.mystrategist.com/medtech-strategist/article/premia_spines_bid_to_solve_lumbar_spines_motionstability_challenge_.html
|website=MedTech Strategist
}}][{{cite web
|title=The invention story
|url=https://premiaspine.com/topstm-system/invention-story/
|website=Premia Spine
}}] The idea was based on clinical observations that many patients undergoing lumbar spinal fusion have preserved intervertebral discs with degenerative spine pathology affecting the posterior elements of the vertebrae, including spinal stenosis, spondylolisthesis, and facet arthrosis. This led to the development of a motion-preserving alternative to fusion designed to maintain spinal stability following decompression.
The first clinical implantations were performed in 2005, followed by international clinical use and subsequent randomized controlled trials comparing the device with fusion.[{{cite journal
|last1=Nassr
|first1=Ahmad
|last2=Coric
|first2=Domagoj
|title=Lumbar Facet Arthroplasty Versus Fusion for Grade-I Degenerative Spondylolisthesis with Stenosis: A Prospective Randomized Controlled Trial
|journal=Journal of Bone & Joint Surgery
|year=2024
|volume=106
|issue=12
|pages=1041–1053
|doi=10.2106/JBJS.23.00719
|pmid=38713762
|pmc=11593996
}}]
=== Randomized clinical trials ===
Randomized controlled trials have compared TOPS to lumbar fusion in patients with lumbar spinal stenosis and grade I degenerative spondylolisthesis. In a large multicenter trial, TOPS demonstrated significantly higher rates of clinical success compared with fusion at two years.[{{cite journal |last1=Nassr |first1=Ahmad |last2=Coric |first2=Domagoj |title=Lumbar Facet Arthroplasty Versus Fusion for Grade-I Degenerative Spondylolisthesis with Stenosis: A Prospective Randomized Controlled Trial |journal=Journal of Bone & Joint Surgery |year=2024 |volume=106 |issue=12 |pages=1041–1053 |doi=10.2106/JBJS.23.00719 |pmid=38713762 |pmc=11593996}}] An earlier multicenter study reported similar findings, with improved patient-reported outcomes relative to fusion.[{{cite journal |last1=Coric |first1=Domagoj |last2=Nassr |first2=Ahmad |title=Prospective, randomized controlled multicenter study of posterior lumbar facet arthroplasty for the treatment of spondylolisthesis |journal=Journal of Neurosurgery: Spine |year=2022 |volume=38 |issue=1 |pages=115–125 |doi=10.3171/2022.7.SPINE22536 |pmid=36152329}}] These improvements included greater reductions in disability as measured by the [Oswestry Disability Index](/source/Oswestry_Disability_Index) (ODI), a standard scale used to assess limitations in daily activities due to back pain.[{{cite journal |last1=Nassr |first1=Ahmad |last2=Coric |first2=Domagoj |title=Lumbar Facet Arthroplasty Versus Fusion for Grade-I Degenerative Spondylolisthesis with Stenosis: A Prospective Randomized Controlled Trial |journal=Journal of Bone & Joint Surgery |year=2024 |volume=106 |issue=12 |pages=1041–1053 |doi=10.2106/JBJS.23.00719 |pmid=38713762 |pmc=11593996}}] Long-term follow-up has shown that TOPS preserves near-normal motion and may reduce the risk of adjacent segment degeneration.[{{cite journal |last1=Smorgick |first1=Yossi |last2=Mirovsky |first2=Yigal |last3=Floman |first3=Yizhar |last4=Rand |first4=Nahshon |last5=Millgram |first5=Michael |last6=Anekstein |first6=Yoram |title=Long-term results for total lumbar facet joint replacement in the management of lumbar degenerative spondylolisthesis |journal=Journal of Neurosurgery: Spine |year=2019 |volume=31 |issue=5 |pages=711–718 |doi=10.3171/2019.7.SPINE19150 |pmid=31585417}}]
== Health economics ==
Economic analyses suggest that TOPS may be cost-effective compared with fusion. These findings are based on improvements in quality of life, faster recovery, and reduced need for reoperation over time.[{{cite journal |last1=Ament |first1=J D |last2=Hsieh |first2=C |last3=Sun |first3=S X |last4=Utrie |first4=P |title=Cost effectiveness of the TOPS System compared to transforaminal lumbar interbody fusion (TLIF) in the treatment of lumbar spinal stenosis with spondylolisthesis: results from the IDE study |journal=Journal of Health Economics and Outcomes Research |year=2022 |volume=9 |issue=1 |pages=76–83 |doi=10.36469/jheor.2022.31747 |doi-broken-date=29 September 2025 |pmid=35664635}}]
==Limitations and safety==
Clinical trials comparing lumbar facet arthroplasty with the TOPS system to lumbar fusion have reported overall complication and reoperation rates that are broadly similar between procedures.[{{cite journal
|last1=Coric
|first1=D.
|title=Prospective, randomized controlled multicenter study of posterior lumbar facet arthroplasty for the treatment of degenerative spondylolisthesis
|journal=Journal of Neurosurgery: Spine
|year=2022
|volume=36
|issue=6
|pages=826–835
|doi=10.3171/2021.10.SPINE21782
}}][{{cite journal
|last1=Nassr
|first1=A.
|title=Two-Year Comparative Results of Lumbar Facet Arthroplasty Versus Fusion in Patients With Lumbar Spinal Stenosis and Degenerative Spondylolisthesis
|journal=The Journal of Bone and Joint Surgery
|year=2024
|volume=106
|issue=5
|pages=403–414
|doi=10.2106/JBJS.23.00315
}}]
Reported adverse events include infection, dural tear, pedicle screw loosening or implant-related complications, and the need for revision surgery.