Supplemental nucleus pulposus allograft in patients with lumbar discogenic pain: results of a prospective feasibility study

Abstract

Background: Degeneration of the intervertebral disc is a significant source of chronic axial low back pain. Direct supplementation of degenerated nucleus pulposis (NP) tissue with intradiscally delivered allogeneic NP represents an opportunity to bridge the treatment gap between failed conservative care and spine surgery for patients with lumbar discogenic pain.

Methods: Prospective, single-arm clinical study conducted at 6 sites in the US. The primary objective was to determine the magnitude of improvement in back pain severity and back function in patients with chronic lumbar discogenic pain at 12 months after a single intradiscal supplementation procedure using a commercially available NP allograft at up to two vertebral levels identified on magnetic resonance imaging. Back pain severity was evaluated using an 11-point numeric rating scale (NRS) and back function using the Oswestry Disability Index (ODI). Minimal clinically important difference (MCID) and substantial clinical benefit (SCB) were set at ≥ 30% and ≥ 50% over baseline, respectively. The patient acceptable symptom state (PASS) threshold for pain severity was ≤ 3.

Results: Twenty-eight participants with a mean age of 44 ± 13 yrs. were enrolled and 22 provided 12-month outcomes. The average overall improvement in back pain severity was 43% through 12 months (p < 0.001). Approximately 64% (14 of 22) achieved the MCID in back pain at 12 months, with 55% (12 of 22) realizing SCB. Almost 60% (13 of 22) reported a 12-month back pain severity score of ≤ 3. The corresponding average decrease in ODI values was 50% (p < 0.001) with approximately 59% (13 of 22) of study participants achieving the MCID. At baseline approximately 82% (23 of 28) of participants reported severe or crippled back impairment compared to 18% (4 of 22) at 12 months (p < 0.001).

Conclusion: The results of this study provide additional evidence that supplementation of the degenerated intervertebral disc with intradiscally delivered allogeneic NP is associated with clinically significant pain palliation and functional improvement.

Trial registration: This trial was prospectively registered at ClinicalTrials.gov on December 30, 2021 (NCT05201287).

Keywords: Allograft; Back pain; Degenerative disc disease; Discogenic; Intradiscal; Nucleus pulposus.

Fig. 1

Line graph showing an average overall longitudinal improvement of 43% in back pain severity scores through 12 months of post-procedure followup (p < 0.001). Mean NRS values are 7.1 (baseline, n = 28), 3.9 (1 month, n = 28), 3.3 (3 months, n = 27), 3.0 (6 months, n = 28) and 3.8 (12 months, n = 22)

Fig. 2

Line graph showing an average overall longitudinal improvement of 50% in back function scores through 12 months of post-procedure followup (p < 0.001). Mean ODI values are 53 (baseline, n = 28), 28 (1 month, n = 28), 24 (3 months, n = 27), 23 (6 months, n = 28) and 24 (12 months, n = 22)

Fig. 3

Comparative distributions of Oswestry Disability Index (ODI) functional impairment categories at baseline and 12 months post-procedure. The difference in these distributions was statistically significant (P < 0.001)