VAST Clinical Trial: Safely Supplementing Tissue Lost to Degenerative Disc Disease

Abstract

Background: The function of the intervertebral disc is structural. Loss of tissue alters biomechanics, leads to subsequent disc degeneration, and is attributable to discogenic pain. A viable structural allograft was delivered into degenerate discs to determine whether intervention could safely stabilize anatomy, reduce pain, and improve function.

Methods: Following institutional review board approval and patient consent, subjects were randomized to receive allograft or saline at either 1 or 2 levels or continue nonsurgical management (NSM). Data were collected at baseline, 3, 6, and 12 months. Back pain with a visual analog scale (VAS) and disability by the Oswestry Disability Index (ODI) were assessed, as were adverse events. This trial is registered on http://www.clinicaltrials.gov (NCT03709901).

Results: At 6 and 12 months, the VAS improved from 54.81, 55.25, and 62.255 in the allograft, saline, and NSM subjects, respectively, to 16.0 and 41.0 in the allograft and saline groups at 6 months, and 12.27 and 19.67, respectively, at 12 months. All subjects in the NSM cohort crossed over to allograft treatment. At 6 and 12 months, ODI improved from 53.73, 49.25, and 55.75 in the allograft, saline, and NSM subjects, respectively, to 18.47 and 28.75 in the allograft and saline groups 1 and 2 at 6 months, and 15.67 and 9.33, respectively, at 12 months. At 3 months the ODI of the NSM group was 62.75 and subjects reached 19.0 and 11.0 at 6 and 12 months, respectively. Adverse events were transient and resolved in all cohorts.

Conclusions: This study is supported by data demonstrating that improved pain and function at 12 months can be attained with a supplemental viable disc matrix. Subjects receiving the VIA Disc Matrix achieved improvements that were durable at 12 months.

Level of evidence: 1.

Clinical relevance: Initial assessments indicate that a 1-level or 2-level treatment offers a reliable intervention that is safe and beneficial.

Keywords: back pain; disc degeneration; supplemental disc allograft; viable disc matrix.

Conflict of interest statement

Disclosures and COI: Dr Beall reports grants from Medtronic, nonfinancial support from Amendia, other from Lilly, other from Synthes, other from Johnson and Johnson, grants from Vitacare, grants from Ortho Kinematics, other from DFine, other from Bone Support, other from Convatec, other from Spinal Ventures, grants from Zyga, grants from Liventa, grants, nonfinancial support and other from Vexim, grants from Mesoblast, grants, personal fees, nonfinancial support and other from Vivex, outside the submitted work.

©International Society for the Advancement of Spine Surgery 2020.

Figures

Figure 1

Disc degeneration is a progressive imbalance of anabolic and catabolic processes that result in tissue loss, which disrupts the anatomy, alters the loading, and results in progressive desiccation. Depiction of disc degeneration based on Thompson Grading.

Figure 2

The study consisted of 2 phases: a screening phase (enrollment) followed by the active phase (12 months). As outlined, there was an indeterminate overlap of up to 2 weeks between the end of the screening phase and the start of the active phase for individual subjects. Subjects met entry criteria for both phases to be eligible and 2 weeks' opportunity was allowed for the subjects to evaluate the protocol and consent to their participation. Although 2 weeks were provided, subjects were eligible following their consent documentation being reviewed and received.

Figure 3

Subjects participating in the VAST Trial were randomized at 3.5:1:1 to receive a supplemental allograft (VIA Disc Matrix), saline as a placebo, or to continue under nonsurgical management (NSM). The assignment of the subjects to treatment (viable matrix supplement, saline placebo, or standard of care) was performed in a randomized manner after informed consent has been obtained.

Figure 4

Reduction in pain was evident in both of the active treatment groups in the study. Subjects who had been randomized to continue nonsurgical management (NSM) demonstrated no relief. The NSM subjects were further evaluated at 3 months (vertical dashed line), and unable to continue, all subjects crossed over to VIA Disc Tissue Matrix. Their response followed the trajectory of the active arms of the study and outcome demonstrated the largest improvement. One subject in the saline-treated group could not continue the study, and after 6 months crossed over to VIA Disc. The horizontal dashed line reflects that progress averaged into the small (4 subjects) placebo group. All patients receiving the randomized allograft completed the study in their cohort. In total, 21 of 24 subjects received the VIA Disc Tissue Matrix either randomized or open label.

Figure 5

Functional improvement was evident in both of the active treatment groups in the study. Subjects who had been randomized to continue nonsurgical (NSM) demonstrated no improvement. The NSM subjects were further evaluated at 3 months (vertical dashed line), and unable to continue, all subjects crossed over to VIA Disc Tissue Matrix. Their response followed the trajectory of the active arms of the study and outcome demonstrated the largest improvement. One subject in the saline-treated group could not continue the study, and after 6 months crossed over to VIA Disc. The horizontal dashed line reflects that progress averaged into the small (4 subjects) placebo group. All patients receiving the randomized allograft completed the study in their cohort. In total, 21 of 24 subjects received the VIA Disc Tissue Matrix either randomized or open label.

Figure 6

MRI images were used to qualify patients for inclusion in the study. Modified Pfirrmann scores between 3 and 6 were acceptable evaluations for participation. Signal intensity and morphologic distinction in the nucleus are noted. More important, pain reduction and functional improvement supported patient satisfaction in the treatment.

Figure 7

Images at 12 months demonstrated improvement in morphology, disc height, and patient indices of pain and functional improvement followed.