Coflex interlaminar implant study shows equivalent or superior results to posterior spinal fusion


A study presented as part of the Eurospine section of Spineweek (28 May–1 June, Amsterdam, The Netherlands) indicates that the Coflex interlaminar implant (Paradigm Spine) is associated with equivalent or superior effects to laminectomy and posterior spinal fusion for the management of spondylolisthesis

Study presenter Joshua Auerbach, assistant professor of surgery, Department of Orthopedics, Bronx-Lebanon Hospital Center, Albert Einstein College of Medicine, Bronx, USA, explained that while patients without spondylolisthesis and with no back pain are typically offered a decompression and patients with grade two spondylolisthesis and severe back pain are commonly offered spinal fusion, the question of how to treat the “patients in the middle” (patients without spondylolisthesis but with severe back pain and stenosis or patients with low-grade spondylolisthesis) remained. He said that there was level one evidence that stabilisation is required in patients with degenerative spondylolisthesis, but that there were significant limitations with fusion–thus, alternatives were being investigated

According to Auerbach, the potential benefits of the Coflex implant, compared with fusion, included reduced operating time, reduced blood loss, shorter hospital stays, maintenance of motion at operative levels, and fewer activity restrictions. He said: “Our hypothesis was that in the treatment of grade one degenerative spondylolisthesis, Coflex interlaminar stabilisation will provide adequate motion segment stabilisation and similar clinical outcomes compared to pedicle screw based lumbar fusion.”

In the prospective, randomised trial, which focused on the spondylolisthesis subset of patients in a US IDE study that compared the Coflex implant with laminectomy and posterior spinal fusion in patients with spinal stenosis or low-grade spondylolisthesis, patients with spondylolisthesis were randomised to receive the Coflex implant (64) or posterior spinal fusion (34). After 24 months, 96.6% of patients in the Coflex group were available for follow-up and 98.6% of patients for the posterior spinal fusion group were available for follow-up. Auerbach reported: “Perioperative outcomes revealed that the hospital length of stay, intraoperative blood loss, and operative times were all significantly reduced in the Coflex group compared with the control group.” He added that the Coflex implant outperformed fusion in each of the Zurich Claudication Questionnaire (ZCQ) subdomains, which were symptom severity (p=0.041), physical function (p=0.048), and patient satisfaction (p=0.015) at 24 months. There were no differences at 24 months in Oswestry Disability Index (ODI) scores, the Visual Analogue Scale back and leg scores, and SF-12 physical component scores between the two groups.

Auerbach stated that primary endpoint of the study was the proportion of patients who achieved “clinical success” which was defined, after 24 months, as a at least 15-point improvement in the ODI score, no revision or removal or supplement fixation, no lumbar epidural steroid injection, and no device related complications. He noted: “We found that 67% of Coflex patients achieved this clinical success compared with 64% of fusion patients.”

Concluding his presentation, Auerbach commented: “Coflex demonstrated equivalent or superior clinical outcomes compared with decompression and fusion for stable grade one spondylolisthesis.” He added that it was a “viable alternative to fusion in degenerative spondylolisthesis.”