Perspective from Vincent C. Traynelis, MD
March 18, 2015
3 min read

Expandable facet joint device alleviated cervical spondylosis symptoms at 2 years

At short-term follow-up, patients who failed nonsurgical management of 1-level radiculopathy and received the device had improved VAS, NDI scores.

Perspective from Vincent C. Traynelis, MD
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ORLANDO, Fla. — In a recent investigation, researchers who investigated the effectiveness of an expandable cervical cage used during indirect posterior cervical decompression for patients with single-level cervical radiculopathy found the device, when placed in the facets, significantly reduced radiculopathy symptoms and pain scores at 24 months follow up.

Kris Siemionow

Kris B. Siemionow

Kris B. Siemionow, MD, presented the findings at the Cervical Spine Research Society Annual Meeting, here. He said researchers found a majority of patients experienced improvements in neck and arm pain, as well as other outcomes, when their physicians used the DTRAX Expandable Cage System (Providence Medical Technology; Lafayette, Calif.) to perform indirect posterior cervical decompression and fusion.

“Indirect decompression and posterior cervical fusion using the DTRAX system may be an effective option in select patients with single-level cervical radiculopathy,” Siemionow said at the meeting.

Decreased pain scores

Sixty patients who failed nonsurgical management of single-level radiculopathy underwent indirect posterior cervical decompression using the DTRAX Expandable Cage System in a multicenter, single-arm study. Investigators evaluated Neck Disability Index (NDI), VAS for neck and arm pain, as well as the SF-12 physical and mental health composite scores, preoperatively and at 2 years after surgery.

Fifty-three patients were available at the 2-year follow up and they were operated on most frequently at C5-6.

Siemionow reported no cases of device migration, expulsion or breakage, as well as no surgical re-interventions during the 24-month period after surgery.


Figure 1. The DTRAX Expandable Cage , manufactured by Providence Medical Technology, works by creating a space in spinal joints where nerves are being pinched as a result of foraminal stenosis. As the screw in it is advanced, the implant distracts and fixates the joint surfaces.

Source: Providence Medical Technology

According to the results, the patients’ average preoperative VAS neck pain score was 7.4 points, which improved significantly at 2 years to 2.6 points (P < 0.0001). Their preoperative VAS arm pain scores of 7.4 points also improved significantly after 2 years to 2.6 points (P < 0.0001).

Significant reduction in NDI

“The NDI was significantly reduced from baseline and that effect was maintained at 24 months, similar for the physical component [score] at 12 months, as well. You can see just a little bit of a non-significant drop by 24 months, though. The mental component was clinically improved and maintained at 24 months, as well,” Siemionow said.

Siemionow said radiographic fusion rates — which did not correlate to outcomes — were 98% in patients. Furthermore, bridging of bone was evident on CT scans.

“Indirect posterior decompression works with sustained benefits” based on data from the study, according to Siemionow’s colleague, Bruce M. McCormack, MD.

He told Spine Surgery Today, “Patients with pinched nerves in their neck due to spondylosis get better with laying down, wearing a soft collar or re-positioning their head. This suggests that subtle adjustment of adjacent vertebra as with DTRAX can alleviate symptoms. Larger reconstructive anterior fusion procedures work, but may be more surgery than necessary and beget more surgeries.” – by Robert Linnehan


McCormack BM, et al. Paper #41. Presented at: Cervical Spine Research Society Annual Meeting; Dec. 4-6, 2014; Orlando, Fla.

For more information:

Bruce M. McCormack, MD, can be reached at the Neurospine Institute Research Group, 2320 Sutter St., Suite 202, San Francisco, CA 94115; email:

Kris B. Siemionow, MD, can be reached at the Illinois Spine and Scoliosis Center, 12701 W. 143rd St., Suite 110, Homer Glen, IL 60491; email:

Disclosures: McCormack owns stock in Providence Medical Technology. Siemionow is a scientific advisor for Providence Medical Technology.