TOPS Procedure vs Minimally Invasive Robotic Spine Fusion: Which Is Right for You?

The TOPS (Total Posterior Spine) System and minimally invasive robotic spine fusion are two surgical approaches for treating lumbar spinal conditions like degenerative spondylolisthesis and spinal stenosis. Both surgical treatments aim to relieve pain and stabilize the spine, but they differ in their methods, outcomes, and long-term implications. This article examines the TOPS procedure vs minimally invasive robotic spine fusion with a critical eye to aid patients in decision-making.

TOPS Procedure vs. Minimally Invasive Robotic Spine Fusion

Overview of the TOPS Procedure

The TOPS System is a dynamic spinal implant designed to stabilize the spine while allowing some motion after decompression surgery. FDA-approved in 2023, it’s marketed as an alternative to spinal fusion for moderate to severe lumbar spinal stenosis and grade I degenerative spondylolisthesis, typically at L3-L5. The procedure involves decompression (e.g., laminectomy or facetectomy) to relieve nerve pressure, followed by implantation of the TOPS device—two titanium plates connected by a polycarbonate urethane boot. This setup purportedly allows controlled motion in all directions while limiting excessive movement.

However, the TOPS System’s novelty raises concerns. Its long-term durability and effectiveness remain unproven in the U.S., with only limited European data since 2012. While short-term studies (up to 24 months) report improvements in pain (Visual Analog Scale) and function (Oswestry Disability Index), the absence of robust, decades-long data casts doubt on its reliability.

The implant’s lifespan—potentially 10-20 years—is speculative, and revision surgery complexity is unknown. It’s also limited to patients with good bone quality and no significant comorbidities like osteoporosis or disc herniation at the surgical level. Additionally, placement of the device involves an “open” surgical approach with a long midline incision and dissection of the paraspinous muscles off the bone. This results in long-term back muscle weakness and atrophy, which is a major contributor to chronic lower back pain.

Overview of Minimally Invasive Robotic Spine Fusion

Minimally invasive robotic spine fusion is a refined version of traditional open fusion, using robot-assisted systems for enhanced precision. It permanently fuses vertebrae to eliminate motion, treating conditions like spondylolisthesis, stenosis, and degenerative disc disease. Small incisions and robotic guidance reduce tissue damage, blood loss, and hospital stays (often 1-2 days) compared to open fusion. Patients may resume light activities within weeks, though full recovery can take up to a few months.

Despite its benefits, fusion sacrifices motion at the treated segment, increasing stress on adjacent vertebrae and risking adjacent segment degeneration (ASD). Complication rates are lower than open fusion, but risks like nonunion (5-10%) persist. Decades of data support its efficacy, making it a well-established option despite long-term drawbacks.

Key Comparisons

All studies that have been conducted comparing TOPS to fusion have been completed using an open approach to fusion. There are currently no studies comparing TOPS with minimally invasive robotic fusion, even though robotic fusion has been shown to be superior to open fusion.

1. Motion Preservation

• TOPS Procedure: Promotes motion preservation, aiming to mimic natural spine biomechanics and reduce adjacent segment stress. However, the device’s ability to maintain controlled motion over decades is untested, and mechanical failure could necessitate complex revisions.

• Minimally Invasive Robotic Spine Fusion: Eliminates motion at the fused segment, creating stability but increasing adjacent segment disease risk. Long-term data confirms this trade-off, with adjacent level issues well-documented. However, if fusing 1 to 2 levels of the spine, there is no significant decrease in overall mobility. Also, adjacent segment disease risk decreases with preservation of the muscle tissue with robotic surgery.

  
  

2. Surgical Approach and Recovery

• TOPS Procedure: Uses an open posterior approach with decompression and device implantation. Patients may walk sooner after surgery, but claims of faster recovery are compared to the open conventional approach to surgery. The procedure’s invasiveness with the approach is the same as an open fusion.

• Minimally Invasive Robotic Spine Fusion: Employs small incisions and robotic precision, minimizing muscle damage. The robot helps to place the hardware through the strands of muscle tissue instead of destroying the tissue. Recovery is faster than open fusion, but restrictions on bending or lifting may last a few months to ensure fusion success.

  
  

3. Clinical Outcomes

• TOPS Procedure: Short-term studies claim superiority over open transforaminal lumbar interbody fusion. However, these results are preliminary, and long-term outcomes are uncertain and again, this is compared to open fusion, which has already been shown to be inferior to robotic minimally invasive fusion.

• Minimally Invasive Robotic Spine Fusion: Offers reliable pain relief and stability, backed by extensive data and shown to be superior to open fusion.

  
  

4. Patient Candidacy

• TOPS Procedure: Restricted to patients aged 35-80 with single-level (L2-L5) grade I spondylolisthesis, moderate to severe stenosis, and good bone quality. Its narrow applicability excludes complex cases or L5-S1 issues.

• Minimally Invasive Robotic Spine Fusion: Suitable for diverse conditions, including multi-level instability or scoliosis, and accommodates poorer bone quality, making it more versatile.

  
  

5. Long-Term Considerations

• TOPS Procedure: The lack of long-term data is a critical concern. European studies provide some insight, but the implant’s durability and revision risks are speculative. Patients face uncertainty about future interventions.

• Minimally Invasive Robotic Spine Fusion: Extensive data confirms risks like ASD and nonunion. While not ideal, these are well-understood, allowing better planning for long-term care.

  
  

Benefits and Risks

TOPS Procedure

Benefits:

• Preserves some spinal motion, potentially reducing adjacent segment stress.

• Short-term pain relief and faster initial recovery compared to open fusion.

Risks:

• No long-term data on implant durability or effectiveness.

• Limited to single-level, specific conditions.

• Requires the same surgical approach as open fusion with weakness and atrophy of paraspinous muscles and risk of future lower back pain.

• Potential device failure or revision surgery risks are unknown.

  
  

Minimally Invasive Robotic Spine Fusion

Benefits:

• Proven efficacy with decades of data.

• Precise robotic guidance reduces complications and tissue destruction.

• Shorter recovery time.

• Suitable for complex spinal issues.

Risks:

• ASD and nonunion risks already studied.

Which Procedure Is Right for You?

The TOPS System’s motion preservation is appealing for active patients with single-level lumbar issues and good bone quality, but its lack of long-term data makes it a gamble. The potential for muscle atrophy and associated chronic low back pain make it less advisable. Minimally invasive robotic spine fusion, while sacrificing motion with larger fusions, offers proven reliability for a broader range of conditions, including complex cases. Patients must weigh the untested promise of TOPS against fusion’s established outcomes.

Research Studies Comparing TOPS System to Open Spinal Fusion

1. Prospective, Randomized Controlled Multicenter Study of Posterior Lumbar Facet Arthroplasty for the Treatment of Spondylolisthesis

   • Publication: Journal of Neurosurgery: Spine, 2023;38(1):115-125

   • Note: The trial is ongoing, with follow-up planned for 5 years, expected completion in 2027.

2. A Prospective Study of Lumbar Facet Arthroscopy in the Treatment of Degenerative Spondylolisthesis and Stenosis: Early Cost-Effective Assessment from the Total Posterior Spine System (TOPS) IDE Study

   • Publication: Journal of Health Economics and Outcomes Research, 2022

3. A Prospective Study of Lumbar Facet Arthroplasty in the Treatment of Degenerative Spondylolisthesis and Stenosis: Cost-effective Assessment from the Total Posterior Spine System (TOPS) IDE Study: 2-year Model Revision and Sensitivity Analysis Based on 305 Subjects.

   • Publication: The Spine Journal, 2024

4. One- and 2-Year Outcomes of Lumbar Facet Arthroplasty versus Spinal Fusion in Young (<65 Years) and Old (≥65 Years) Patients for the Treatment of Degenerative Spondylolisthesis and Stenosis

   • Publication: North American Spine Society Journal 2024

5. Mean 5-Year Follow-Up Results of a Facet Replacement Device in the Treatment of Lumbar Spinal Stenosis and Degenerative Spondylolisthesis

   • Publication: World Neurosurgery, 2021