Posterior Lumbar Facet Fusion (CORUS-LX™) | Jonathan G. Hobbs, M.D.

The procedure

What Is Posterior Lumbar Facet Fusion?

Every level of the low back is joined by three joints: the disc in front and a pair of facet joints at the back. A lumbar fusion stops the painful motion at a level by replacing the disc with a cage and then holding everything still until bone grows across. For decades, “holding it still” has meant pedicle screws and rods placed through a sizable exposure of the back muscles.

Posterior lumbar facet fusion moves that fixation into the facet joints themselves. Through a mini-open portal no larger than 16 mm on each side, the joint is prepared and a CORUS-LX implant is seated across it. The implant has an integrated self-locking screw and doubles as a reservoir for bone graft, so each facet is fixed and grafted in one step. With a cage in front and an implant in each facet behind, the level is held at three points around the disc.

CORUS-LX is indicated for posterior lumbar fusion in lumbar degenerative disc disease from L4 to S1, as an adjunct to a one- or two-level interbody fusion. It is always paired with an FDA-cleared interbody device at the same level, and it can be used with or without pedicle screws and rods. It is the lumbar relative of the DTRAX cervical system Dr. Hobbs uses in the neck.

Interactive — step by step

How the Facet Fixation Is Placed

Tap each step. The same sequence is repeated on the other side of the spine, and at the second level when two are fused.

Top-down illustration of a lumbar vertebra with an interbody cage in the disc space and a CORUS-LX implant in each facet joint, connected by an orange triangle marking three points of fixation — A cage in front and an implant in each facet joint: three points of fixation around the level.

Simplified illustration for education, courtesy of the manufacturer; not an exact anatomical depiction. Pedicle screws and rods are added when Dr. Hobbs wants additional stability.

Bench testing

As Stiff as Screws and Rods?

A fusion heals when the level stops moving. In a 2025 biomechanical study, cadaver spines were fused at L2–L3 with a lateral interbody cage (LLIF) and then tested three ways: the cage alone, the cage with pedicle screws and rods, and the cage with CORUS-LX facet fixation.

Either form of posterior fixation cut motion sharply compared with the cage alone. Facet fixation matched or bettered the screw-and-rod construct in flexion, extension, and axial rotation, and allowed a little more motion in lateral bending. The authors called it a viable alternative for adding stability to lateral interbody fusion.

This is a cadaver study at one level above the range CORUS-LX is cleared for, and it was presented as a meeting ePoster rather than a peer-reviewed paper. It shows how the construct behaves mechanically, not how patients do.

Average motion at L2–L3, degrees

Lower is stiffer. Values for the CORUS-LX construct are labeled; hover any bar for its value.

View the data table

Motion tested	LLIF alone	LLIF + pedicle screws and rods	LLIF + CORUS-LX facet fixation
Flexion	0.84°	0.10°	0.06°
Extension	0.81°	0.32°	0.28°
Lateral bending	1.22°	0.43°	0.56°
Axial rotation	0.53°	0.43°	0.28°

Values read from the chart published by the manufacturer; approximate to about 0.02°. Zhou et al., “Biomechanical stability of LLIF with posterior intrafacet fixation,” ePoster, Spine Summit 2025. Source.

Who it is for

Who Is a Candidate?

Facet fixation is a way to hold a fusion, not a reason to have one. Dr. Hobbs considers it for skeletally mature adults who already need a one- or two-level lumbar fusion at L4–S1 and who:

Have exhausted conservative care

Physical therapy, medication, and usually injections have been tried without lasting relief from degenerative disc disease at the lowest lumbar levels.

Are higher risk for hardware problems

Older patients, softer bone, or prior surgery, where anchoring in the densest bone of the segment is an advantage. The clinical data for the system come from high-risk and revision patients.

Are having a lateral or anterior interbody fusion

LLIF and ALIF place the cage from the side or front; facet fixation adds posterior stability without a second large incision in the back. See spinal fusion approaches.

Need a revision with a smaller footprint

A level that did not heal, or a level next to an old fusion, where Dr. Hobbs wants solid fixation with less muscle disruption. See revision spine surgery.

When Dr. Hobbs recommends something else

Levels above L4. The lumbar system is indicated for L4–S1; higher levels use other fixation.
Instability or deformity that needs correction. Slips, curves, and alignment problems call for pedicle screw constructs planned to your alignment, sometimes with facet fixation added. See adult scoliosis and spondylolisthesis.
No fusion needed at all. Many lumbar problems are treated with decompression alone or with motion-preserving options; facet fixation is never used without an interbody cage.

Compare

Three Ways to Hold a Lumbar Fusion

Each has a job it does best. The right one depends on your bone, your alignment, and how many levels are involved.

	Facet fixation (CORUS-LX) + cage	Pedicle screws and rods + cage	Cage alone
Where it anchors	The facet joints, the densest bone in the segment	The pedicles, through to the vertebral body	The disc space only
Approach	Mini-open portal about 16 mm on each side; muscle spread	Open or percutaneous posterior exposure	No posterior incision
Stiffness on the bench	Comparable to screws and rods in flexion, extension, and rotation; a little more motion in lateral bending	The traditional standard	Least; relies on the cage and the patient’s own ligaments
Hardware profile	Low; sits inside the joint	Screw heads and rods above the bone	None posteriorly
Best for	One- or two-level fusions at L4–S1, including high-risk and revision patients	Deformity, instability, and multilevel constructs	Selected single levels with good bone and alignment

The approaches are often combined: facet fixation can be added to a screw-and-rod construct, and a cage is always part of the plan. Dr. Hobbs matches the construct to your imaging and bone quality.

Evidence

What the Early Data Show

Lumbar facet fixation is newer than its cervical cousin, and most of the data so far come from the manufacturer. Here is what has been reported.

96%Fusion rate

Defined as less than 5 degrees of motion on X-ray, in a study of 57 high-risk and revision patients treated with the lumbar facet fixation system as an adjunct to interbody fusion.

Manufacturer study CLN-PMT-145, Providence Medical Technology

73%Bridging bone across the interbody, facets, and segment

In the same 57-patient series; 79 percent of patients reported improved pain.

Manufacturer study CLN-PMT-145

2.7×Denser bone in the facet than in the vertebral body

About 392 versus 147 mg/mL, with roughly five times the cortical fraction, in a CT study of the lumbar segment.

Odeh et al., Global Spine J, 2021

≈PSRMotion reduction comparable to pedicle screws and rods

In cadaver testing of lateral interbody fusion at L2–L3, across flexion, extension, lateral bending, and axial rotation.

Zhou et al., ePoster, Spine Summit 2025

About these numbers. They come from manufacturer-reported and bench studies, not from Dr. Hobbs’s own patients, and the clinical series is small with an unstated follow-up period. Independent, peer-reviewed results for the lumbar system are still limited. Dr. Hobbs will explain how they apply to your situation.

Recovery

Recovery & Healing

The implants do their job immediately. The bone takes longer. Recovery follows the interbody fusion it supports; the smaller posterior footprint mainly changes the first weeks.

Surgery Day
General anesthesia. The facet implants are placed through two small portals, usually in the same operation as the cage. Most patients are walking the same day; the hospital stay depends on the interbody approach and the number of levels.
The First Weeks
Walking and light daily activity resume quickly. Bending, lifting, and twisting are limited while the construct protects the level. Soreness at the portals fades over a couple of weeks.
3 to 6 Months
This is when bone bridges the disc space and the facet joints. Activity is increased step by step, therapy rebuilds core strength, and Dr. Hobbs confirms healing on follow-up imaging.

Technology

Part of a Minimally Invasive Practice

Facet fixation sits alongside the other tools Dr. Hobbs uses to fuse a level with the smallest footprint that solves the problem.

Spinal Fusion & Stabilization
How a fusion is built and the ways to reach the spine

Image-Guided Navigation
Real-time guidance confirms the level and the path

Personalized Interbody Cages
3D-printed to your anatomy for the front of the construct

Minimally Invasive Technique
Muscle-sparing approaches across the spine

Jonathan G. Hobbs, M.D.

Board-Certified Neurosurgeon · Spine Surgery

ABNS
Certified

Residency
Chicago

M.D.
Kentucky

Why Dr. Hobbs

Why Choose Dr. Hobbs for Lumbar Fusion

The Whole Toolkit
Facet fixation, pedicle screws, patient-specific cages and rods, and navigation, chosen per patient rather than one construct for everyone.
Tissue-Sparing Focus
Specialty-trained in minimally invasive techniques; the same facet-based approach is part of his cervical practice with DTRAX.
Conservative-First
Fusion is considered only after nonsurgical care has failed and imaging confirms the level.
Revision Experience
Levels that did not heal, or that failed next to an old fusion, are a regular part of his practice.
Elite Training
University of Kentucky medical degree; neurosurgery residency at the University of Chicago, serving as chief resident.
Lakeshore Bone & Joint Institute
Practicing at Northwest Indiana's most preferred orthopedic and spine practice, with offices in Crown Point & Chesterton.

Call (219) 250-5010 The full surgical process

Related: Degenerative disc disease· Spinal fusion· Revision spine surgery· Lumbar MRI guide

Frequently Asked Questions About Lumbar Facet Fusion

It is a way of locking a painful level of the low back from behind by placing a small implant across each facet joint, the pair of small joints at the back of every spinal level. The CORUS-LX implant spans the facet, locks with an integrated self-locking screw, and holds bone graft so the joint fuses. It is used together with an interbody cage at the same level, through a tissue-sparing approach about 16 mm wide on each side. Dr. Hobbs uses it as an adjunct to one- and two-level lumbar fusions from L4 to S1.

They come from the same company, Providence Medical Technology, and share the same idea: fuse the facet joints from behind through narrow, tissue-sparing instruments instead of a large open exposure. DTRAX® is the cervical system Dr. Hobbs uses for posterior cervical fusion. CORUS-LX is the lumbar system, with an implant and integrated screw sized for the much larger facet joints of the low back, and it is indicated for L4 to S1 as an adjunct to interbody fusion.

Because the facet is the densest bone in the lumbar segment. A 2021 CT study found the inferior articular process (part of the facet) averaged about 392 mg/mL of bone mineral density with about 51 percent cortical bone, compared with about 306 mg/mL and 36 percent for the pedicle and about 147 mg/mL and 11 percent for the vertebral body. Dense bone holds hardware better, which matters most in older patients and in revisions.

In some patients, yes; in others it is added to them. In a bench study of lateral lumbar interbody fusion at L2-L3, adding CORUS-LX cut motion as much as adding pedicle screws and rods in flexion, extension, and axial rotation, and somewhat less in lateral bending. The system is cleared for use with or without a pedicle screw and rod system at the same level. Dr. Hobbs decides based on your bone quality, alignment, and how many levels are being fused.

Skeletally mature adults with lumbar degenerative disc disease at L4-L5 or L5-S1 who have not improved with conservative care and need a one- or two-level fusion. It is particularly useful when Dr. Hobbs wants posterior fixation with a smaller footprint: in high-risk or revision patients, and behind lateral or anterior interbody fusions. It is not a standalone device, it is not used above L4, and significant instability or deformity still calls for pedicle screw constructs planned to your alignment.

A manufacturer-reported study of the lumbar facet fixation system in 57 high-risk and revision patients found 96 percent fusion, defined as less than 5 degrees of motion on X-ray, 73 percent bridging bone across the interbody and facets, and 79 percent of patients with improved pain. A 2025 biomechanical study found motion reductions comparable to a pedicle screw construct. These are early, manufacturer-associated data from small groups, not results from Dr. Hobbs’s own patients.

Yes. Jonathan G. Hobbs, M.D. is a board-certified neurosurgeon who uses the Providence Medical Technology CORUS-LX system for appropriate patients as part of one- and two-level lumbar fusions. He practices at Lakeshore Bone & Joint Institute, with offices in Crown Point & Chesterton, Indiana. Call (219) 250-5010 to schedule a consultation.

Find Out How Your Fusion Would Be Held.

If a lumbar fusion has been recommended, Dr. Hobbs will review your imaging and explain whether facet fixation, pedicle screws, a combination, or continued conservative care is the right next step for your bone and your alignment.

(219) 250-5010

Monday – Friday · 8:00 AM – 4:30 PM

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500 E. 109th Avenue
Crown Point, IN 46307

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601 Gateway Boulevard
Chesterton, IN 46304

Posterior Lumbar Facet Fusion