Abstract
Background Lumbar fusion eliminates motion at the operative level and is associated with altered load transfer and adjacent segment degeneration. Total joint replacement (TJR) of the lumbar spine is a motion segment reconstruction procedure performed via a bilateral transforaminal approach that allows direct neural decompression and replacement of both disc and facet function. This prospective investigational device exemption clinical trial compared TJR with a concurrent, propensity-score-weighted real-world evidence cohort treated with either instrumented transforaminal lumbar interbody fusion (TLIF) or posterior lumbar interbody spine fusion (PLIF).
Methods This multicenter investigational device exemption trial was conducted at 20 US sites. Patient-reported outcomes from 152 TJR subjects implanted with the MOTUS device were compared with 142 propensity score–weighted TLIF/PLIF controls. Lumbar-related disability was measured with the Oswestry Disability Index (ODI) and back and worst leg pain severity by a 100-mm visual analog scale (VAS). Minimal clinically important difference thresholds were ODI ≥ 15 points and VAS ≥ 20 mm; responder analyses were also conducted using ≥30% and substantial clinical benefit (≥50%) thresholds. Effect sizes were calculated using Cohen’s d or h.
Results Baseline characteristics were well balanced, and there were no statistically significant differences between study groups. At 12 months, mean ODI decreased by 45 points (71%) with TJR and 37 points (59%) with TLIF/PLIF. The adjusted between-group difference was 8.1 points (95% CI, 2.5–13.7; P = 0.005; Cohen’s d = 0.39, small). VAS back and leg pain decreases were similar between groups, with no significant between-group differences. Minimal clinically important difference responder rates were high (>85%) for both procedures; the ≥30% ODI threshold favored TJR (90% vs 80%; P = 0.04).
Conclusions Substantial decreases in back impairment and pain severity were realized in both study groups. However, longitudinal improvement in ODI significantly favored patients treated with TJR.
Clinical Relevance Lumbar TJR combines decompression with motion preservation in a single procedure, potentially offering an alternative to fusion in selected patients. The advantage of utilizing a standard posterior operative approach with TJR is that it allows for direct decompression of the neural elements prior to implant placement.
Level of Evidence 2b.
Introduction
Degeneration of the lumbar spine commences as early as the third decade of life.1 Loss of intervertebral disc structure and integrity often precipitates a progressive cycle of advancing structural degeneration, eventually involving the posterior facet joints. These degenerative changes can ultimately result in compression of the neural elements, producing clinical symptoms of low back pain, radiculopathy, and/or neurogenic claudication.2 When nonsurgical measures fail to provide pain relief and functional improvement, surgical decompression of the neural elements is indicated.3,4 Instrumented fusion is often performed in conjunction with decompression to re-establish stability across the vertebral motion segment.4,5 However, surgical arthrodesis has the untoward consequence of eliminating natural motion at the operative level, permanently altering stress distribution in the lumbar spine, resulting in accelerated degeneration and function at adjacent levels.6,7
Total joint replacement (TJR) of the lumbar spine offers a motion-preserving approach to the surgical treatment of lumbar degeneration.8–11 Lumbar TJR couples the clinical benefits of neural decompression with dynamic stabilization while preserving/restoring natural motion and sagittal balance at the operative level.12 The TJR procedure involves reconstruction of the entire motion segment using a posterior lumbar bilateral transforaminal approach to access the disc space.13 The TJR implant replaces the function of the intervertebral disc and facet joints, performing biomechanically as a replacement articulation that provides the advantages of disc and facet arthroplasty using a single implant system.10,12–14
A multicenter clinical trial was conducted to determine the safety and effectiveness of TJR compared with instrumented interbody fusion in the surgical treatment of symptomatic lumbar spinal degeneration. The present article is the initial report of patient-reported outcomes in patients with 12 months of clinical follow-up.
Methods
Study Design, Setting, and Subjects
This article reports an ongoing prospective investigational device exemption clinical trial conducted at 20 academic and private practice sites in the US using a propensity score (PS) weighted study design.15 This methodology employed 2 separate observational trials of different surgical treatments of patients screened with identical eligibility criteria. The design of the 2 separate studies featured several elements intended to ensure comparability of patients between study groups. Both studies were undertaken at the same investigative sites using the same surgical teams. All study participants had a primary diagnosis of symptomatic lumbar degeneration with or without foraminal or recess stenosis of the lumbar spine at a single level from L1/L2 to L5/S1. The control intervention was instrumented transforaminal lumbar interbody fusion (TLIF) or posterior lumbar interbody fusion (PLIF), and the investigational intervention was TJR of the lumbar spine.
Symptomatic lumbar degeneration was defined as leg pain or neurological symptoms with or without back pain due to recurring herniated nucleus pulposus, ligamentum flavum hypertrophy, facet degeneration, osteophyte formation, disc degeneration, and/or annular degeneration, often causing spinal stenosis (radiculopathy, nerve root compression, absent neurological deficit, radiculitis, or neurogenic claudication).
The 2 studies spanned staggered but overlapping time frames, with the study of TLIF/PLIF participants commencing in May 2021 and TJR participants in June 2022. Enrollment for both studies was substantially complete in December 2023. At all sites, the TLIF/PLIF study was initiated first. Postoperative follow-up for both studies was conducted at 6 weeks; 3, 6, 12, and 24 months (primary endpoint); and 3–5 years. The primary objective was to determine the clinical effectiveness of TJR compared with TLIF/PLIF in the treatment of patients with symptomatic lumbar degeneration.
The study population included patients requiring surgical treatment at one affected level from L1/L2 to L5/S1 for leg pain and/or neurological symptoms with or without back pain due to symptomatic lumbar degeneration with or without stenosis, confirmed by radiographic imaging, with no more than a grade 1 spondylolisthesis at the involved level.
Specific inclusion criteria included men or women, age 21 to 80 years (inclusive) with at least 3 years of life expectancy; primary diagnosis of symptomatic lumbar degeneration with or without foraminal or recess stenosis of the lumbar spine at a single level from L1/L2 to L5/S1 confirmed by patient history and radiographic imaging (computed tomography, magnetic resonance imaging, and x-rays) with no more than a grade 1 (<25% translation) spondylolisthesis. Symptomatic lumbar degeneration may be associated with a comorbid condition such as: herniated nucleus pulposus; scarring/thickening of the ligamentum flavum, annulus fibrosus, or facet joint capsule; facet joint degeneration/osteophyte formation; spondylosis (defined by the presence of osteophytes); disc degeneration and/or annular degeneration; and/or lumbar stenosis defined by spinal cord or nerve root compression; exhausted nonsurgical treatment (eg, bed rest, physical therapy, medications, transcutaneous electrical nerve stimulation [TENS], manipulation, and/or spinal injections) for at least 3 months or has a neurological emergency; preoperative Oswestry Disability Index (ODI) score ≥40/100 at baseline.
Corresponding exclusion criteria included more than 1 vertebral level requiring treatment; previous instrumented surgery (ie, anterior disc replacement, spinal fusion, interspinous device, etc.) at the index lumbar level or an adjacent level; degenerative or lytic spondylolisthesis greater than grade 1 (<25% translation); rotatory scoliosis at the level to be treated; congenital bony and/or spinal cord abnormalities at the level to be treated; subcaudal defect, disrupting the integrity of the pedicle; clinically compromised vertebral bodies at the involved level due to current or past trauma, for example, by the radiographic appearance of the fracture callus, malunion, or nonunion; disrupted anterior longitudinal ligament at the index level; overlying thoracolumbar kyphosis (≥15°) within 1 level (includes target and adjacent level) of the level to be treated; back pain of unknown etiology without leg pain; severe spondylosis at the level to be treated as characterized by any of the following: autofusion (solid arthrodesis) determined via computed tomography; totally collapsed disc; vertebral body that cannot be mobilized; or osteopenia. The SCORE/MORES were utilized for all women aged <50 years and men aged <55 years to screen whether dual-energy x-ray absorptiometry (DXA) was indicated. If the SCORE/MORES value was ≥6, then DXA was required. DXA was indicated for all women aged ≥50 years and all men aged ≥55 years. If DXA was required, exclusion was defined as a DXA bone density measured T score ≤ −1; history of any endocrine or metabolic disorder known to affect osteogenesis (eg, Paget’s disease, renal osteodystrophy, Ehlers-Danlos syndrome, or osteogenesis imperfecta); insulin-dependent diabetes mellitus; lactating, pregnant, or interested in becoming pregnant in the next 3 years; active infection—systemic or local; any medical condition requiring treatment with any drug known to potentially interfere with bone/soft tissue healing or receiving radiation therapy that is expected to continue for the duration of the study; body mass index >40; recurrent history of deep vein thrombosis, symptoms of arterial insufficiency, or thromboembolic disease; systemic disease including lupus disease, Reiter’s disease, rheumatoid disease, AIDS, HIV, hepatitis, or autoimmune disease that requires immunosuppressive therapy, including biologics, for systemic inflammation; spinal tumor; active malignancy; any degenerative muscular or neurological condition that would interfere with evaluation of outcomes, including but not limited to Parkinson’s disease, amyotrophic lateral sclerosis, or multiple sclerosis; chronic or acute renal and/or hepatic impairment and/or failure or prior history of renal and/or hepatic parenchymal disease; Waddell Signs of Inorganic Behavior score of 3 or greater; current or recent history of chemical/alcohol abuse or dependency using standard medical definition of Diagnostic and Statistical Manual of Mental Disorders-5 code; currently smoking or using tobacco products, including e-cigarette products (eg, vaping); currently participating in an investigational therapy (device and/or pharmaceutical) within 30 days prior to entering the study or such treatment is planned during the 24 months following enrollment into the study.
The sample size for this study was determined adaptively within a coherent Bayesian Adaptive Design framework. The clinical expectation of assumed success rates of investigational and control arms was based on data collected in a previous pilot study of TJR.10 These data supported the assumption of expected success rates of 0.620 for TJR and 0.560 for TLIF/PLIF.
Given these expected success rates for TJR and TLIF/PLIF, an initial power calculation specified that 135 subjects per study provides 85% power for a frequentist 1-sided alpha 0.05 with a 0.10 noninferiority margin. For this publication, the final sample included 152 patients with the investigational TJR device implant and 142 of 174 (82%) eligible fusion control participants (32 controls had PS values outside the common 10% extended region of support and were thus trimmed from the final design) determined through a Bayesian Adaptive Design.
Institutional review board (IRB) review and approval was issued by Western-Copernicus Group IRB separately for the TLIF/PLIF (20211903) and TJR (20222831) studies, and both studies were conducted in adherence with the Declaration of Helsinki.
Real-World Evidence Study
The initial study was undertaken to provide a real-world evidence (RWE) comparison group of patients treated with single-level TLIF/PLIF and was prospectively registered at clinicaltrials.gov (NCT04823858). The RWE study was designed to utilize a non-concurrent historical control group with patient-level data in a parallel group design. In addition to collecting data at all the clinical sites studying the TJR device, the RWE study also utilized the same data collection methods and assessment instruments (eg, subject eligibility criteria, patient-reported outcome measures), radiographic assessments, and clinical site monitoring).
Investigators were instructed to select only those patients who were planned for treatment with on-label use of US Food and Drug Administration-cleared TLIF/PLIF devices (cage and screw system). All procedures involved standard of care TLIF or PLIF instrumented with pedicle screws at a single level following decompression at 1 or 2 contiguous levels. Any FDA-cleared lumbar interbody cage and pedicle screw system was acceptable for this study (with the exception of polyetheretherketone rods). Bone morphogenetic protein or any other biological material (including cell-based allograft materials) was not permitted.
Investigational Device Exemption Clinical Trial
The second study was undertaken at 13 of the same 20 RWE clinical sites and designed to collect safety and effectiveness data on patients who planned to undergo single-level TJR of the lumbar spine using the MOTUS device (3Spine, Chattanooga, TN, USA; (Figure 1) and prospectively registered at clinicaltrials.gov (NCT05438719).
The MOTUS device (3Spine, Chattanooga, TN, USA).
TJR is indicated for the biomechanical reconstruction and stabilization of a spinal motion segment following decompression at 1 lumbar level from L1/L2 to L5/S1 for skeletally mature patients due to symptomatic lumbar degeneration with or without foraminal or recess spinal stenosis confirmed by radiographic imaging (computed tomography, magnetic resonance imaging, and x-ray imaging), with no more than a grade 1 spondylolisthesis at the involved level.
The TJR procedure is a lumbar motion segment reconstruction that involves device implantation using a bilateral transforaminal lumbar interbody approach to access the disc space. Laminectomy, bilateral facet removal, and partial discectomy are used to achieve a wide central and bilateral decompression of the neural elements. The lateral annulus and anterior longitudinal ligament are preserved to maintain soft tissue tension and stability when disc height is restored. Additional surgical preparation includes 3-column corrective pedicle vertebral body osteotomy of the superior portion of the inferior vertebral body, keel cuts, soft tissue tensioning, distraction of partially collapsed disc space, as well as height and length trialing. The treated segment receives 2 implants, inserted bilaterally along the trajectory of the pedicles following complete facetectomy, such that the midpoint of the ball-in-socket of the implant is approximately 40% ventral to the posterior vertebral body, which is consistent with the physiological center of rotation. The implant has a titanium plasma spray ongrowth surface at the bone interface, and initial fixation is achieved via the keels and placement of a retention screw into the caudal portion of the implant, which passes obliquely through the pedicle and into the vertebral body of the caudal level (Figure 2).8,13
Final implant placement showing the rectangular implant resting on posterior superior S1 with the L5 to S1 segment in lordosis. The wedge-shaped pedicle vertebral body osteotomy of S1 allows the rectangular implant to rest in the disc space while maintaining segmental lordosis.
Patient-Reported Outcome Measures
The degree of back disability was measured using the ODI and back and worst leg pain severity by a 100-mm visual analog scale (VAS). The computation of responder rates for the primary endpoint was based on a minimal clinically important difference (MCID) of ≥15 points for ODI and ≥20 mm for VAS compared with baseline. These results were confirmed using a success threshold of ≥30% over baseline as the MCID.16,17 Substantial clinical benefit (SCB) for both ODI and VAS was defined as ≥50% improvement compared with baseline.18 Responder rates for VAS patient acceptable symptom state (PASS) scores were also computed with success thresholds set at ≤40 mm and ≤30 mm.19,20
The primary endpoint for this study was to assess the PS-calibrated change from baseline in ODI between the TRJ and RWE groups. All other assessments were considered secondary or exploratory, including assessments of any MCID, SCB, or PASS for ODI or VAS.
Statistical Analyses
The PS design utilized PS-based weights designed to estimate the average treatment effect on the treated causal estimand. Specifically, the subject-specific weights were equal to 1.0 for MOTUS investigational participants and equal to the odds of exposure (equals PS/[1-PS]) among the RWE control participants. The PS value used to derive the weights was selected based on evaluation of covariate balance achieved across a sequential set of logistic regression models identified through a logistic regression with forced retention of all main effect terms and additional higher ordered terms (squares of continuous covariates and pairwise interactions between all covariates) identified through a forward selection algorithm with a P < 0.05 threshold for model entry.
The PS-calibrated mean difference in ODI and VAS changes from baseline to 12 months between TJR and TLIF/PLIF groups was estimated using a t test–generated 95% 2-sided confidence interval. McNemar’s analysis of correlated proportions was used to compare the responder rates between study groups. Effect sizes for continuous outcomes were calculated using Cohen’s d and for responder rates using Cohen’s h statistic.21 Effect sizes were classified as small (≥0.2), medium (≥0.5), and large (≥0.8). Love plots were used to show the effect sizes of the baseline characteristics before and after the PS weights were applied.
Results
The TJR group included 99 men and 53 women, and the TLIF/PLIF group consisted of 81 men and 61 women. Baseline characteristics were similar between groups, with no statistically significant differences in mean age (50.4 vs 51.8 years), body mass index (28.9 vs 29.2), ODI (63.1 vs 62.8), VAS back (75.6 vs 75.0 mm), or VAS worst leg pain (70.2 vs 74.7 mm; P > 0.13 for all comparisons).
Both study groups realized significant changes in ODI scores between baseline and 12 months (Figure 3). There were 45-point (71%) and 37-point (59%) average decreases in ODI at 12 months compared with baseline for TJR and TLIF/PLIF, respectively, and the average between-group difference (8.1, 95% CI [2.5, 13.7]) was statistically significant (P = 0.005). The corresponding between-group effect size of longitudinal change in ODI was 0.39, reflecting a small treatment effect, but this treatment effect was statistically significant. The comparative 12-month ODI responder rates based on a ≥15-point MCID were 91% (139 of 152) and 85% (120 of 142) for TJR and TLIF/PLIF, respectively, and the difference was not statistically significant (P = 0.16). Utilizing a ≥30% MCID success threshold over baseline, however, resulted in a statistically significant difference between groups (90% vs 80%, P = 0.04). Both groups also realized SCB with 82% (124 of 152) and 70% (100 of 142) of participants reporting ≥50% improvement in ODI scores by 12 months postsurgery (P = 0.06). Corresponding effect sizes for all 12-month ODI success proportions reflected small treatment effects in favor of TJR (range, 0.19–0.27).
Line graph showing an average (95% CI) overall longitudinal reduction of 71% for total joint replacement (TJR) and 59% for transforaminal lumbar interbody fusion (TLIF)/posterior lumbar interbody fusion (PLIF) in Oswestry Disability Index (ODI) scores through 12 months of postoperative follow-up (P = 0.005). Mean ODI values were 63 and 63 at baseline, 25 and 32 at 3 mo, 22 and 26 at 6 mo, and 18 and 26 at 12 mo for TJR and TLIF/PLIF, respectively.
Subjects treated with TJR realized an average 51-point (66%) decrease in VAS back pain severity through 12-month follow-up compared with an average 46-point (59%) decrease after TLIF/PLIF (Figure 4). The corresponding average between-group difference in change from baseline (−5.7 mm, 95% CI [−13.3, 1.9]) was not statistically significance (P = 0.14), reflecting a small effect size (0.2). Twelve-month responder rates were similar between TJR and TLIF/PLIF but consistently favored participants treated with TJR. Specifically for TJR and TLIF/PLIF, respectively, the responder rates were as follows: ≥20 mm MCID (86% [131 of 152] vs 84% [119 of 142]; P = 0.62), ≥30% MCID (90% [137 of 152] vs 87% [123 of 142]; P = 0.39), SCB (82% [125 of 152] vs 77% [109 of 142]; P = 0.34), as well as PASS thresholds set at ≤40 mm (77% [117 of 152] vs 66% [94 of 142]; P = 0.09) and ≤30 mm (68% [103 of 152] vs 59% [84 of 142]; P = 0.22). Corresponding effect sizes for all 12-month VAS back pain success proportions reflected negligible to small treatment effects (range, 0.07–0.24).
Line graph showing an average (95% CI) overall longitudinal decrease of 66% for total joint replacement (TJR) and 59 % for transforaminal lumbar interbody fusion (TLIF)/posterior lumbar interbody fusion (PLIF) in visual analog scale (VAS) back pain severity scores through 12 months of postoperative follow-up (P = 0.14). Mean VAS values were 76 and 75 at baseline, 27 and 31 at 3 mo, 31 and 31 at 6 mo, and 24 and 30 at 12 mo for TJR and TLIF/PLIF, respectively.
We also noted similar changes in VAS worst leg pain severity for both study groups (TJR: 65%, TLIF/PLIF: 57%) over the 12-month study follow-up (Figure 5). The average between-group difference in change from baseline was −1.8 mm (95% CI [−9.6, 6.0]; P = 0.65) with a corresponding negligible effect size of 0.06. Twelve-month responder rates for TJR and TLIF/PLIF were 86% (130 of 152) vs 88% (125 of 142; P = 0.62) for the ≥20 mm MCID, 90% (137 of 152) vs 87% (123 of 142; P = 0.39) for ≥30% MCID, 82% (125 of 152) vs 77% (109 of 142; P = 0.34) for SCB, 86% (130 of 152) vs 76% (108 of 142; P = 0.10) for ≤40 mm, and 81% (123 of 152) vs 68% (96 of 142; P = 0.04) for ≤30 mm PASS thresholds. Corresponding effect sizes for all 12-month success proportions reflected negligible to small treatment effects (range, −0.07–0.30).
Line graph showing an average (95% CI) overall longitudinal decrease of 65% for total joint replacement (TJR) and 57% for transforaminal lumbar interbody fusion (TLIF)/posterior lumbar interbody fusion (PLIF) in visual analog scale (VAS) worst leg pain severity scores through 12 mo of postoperative follow-up (P = 0.65). Mean VAS values were 70 and 75 at baseline, 19 and 23 at 3 mo, 19 and 22 at 6 mo, and 17 and 23 at 12 mo) for TJR and TLIF/PLIF, respectively.
Discussion
Participants in both studies realized substantial improvements in ODI disability scores as well as back and worst leg pain, with 12-month responder rates ≥85% for ODI irrespective of surgical treatment. While there was no notable deterioration in clinical performance for either treatment at this follow-up interval, we did detect a significantly larger longitudinal decrease in ODI scores for patients treated with TJR (P = 0.005). Additionally, we also noted significantly higher 12-month responder rates favoring TJR for ODI (≥30% threshold improvement) as well as VAS worst leg pain (≤30 mm threshold). This latter finding, the PASS, has been shown to be an important clinical metric for differentiating whether a patient truly feels well as opposed to simply feeling better.20,22
There remains a keen interest in developing and commercializing motion preservation strategies as an alternative to arthrodesis to combat lumbar spinal degeneration.11,23–25 Headwinds for clinical adoption have been strong, but lumbar disc arthroplasty has slowly but increasingly garnered recognition as a viable surgical option. The concept of motion-preserving spinal surgery has more recently been expanded to include facet replacement as a means of addressing posterior column degeneration.26 However, lumbar degeneration most commonly affects the entire 3-joint complex,2 requiring a more comprehensive surgical solution such as TJR. Importantly, utilizing a posterior operative approach with TJR allows for direct decompression of the neural elements, which broadens the population of patients that can potentially benefit from a motion-sparing procedure.
It should be noted that the present study did not randomly allocate treatment assignment; rather, this trial employed a PS study design that predicts treatment effects using observational data to create a weighted sample of participants who received or did not receive the experimental intervention based on their PSs, which takes into account characteristics such as age, gender, and comorbidities to facilitate a more accurate estimation of the treatment effect even without random treatment assignment.27 This trial also has the important advantage of being prospectively designed to control a variety of variables, such as using the same clinical sites, similar sample sizes, and identical inclusion and exclusion criteria, so that both underlying studies facilitate valid comparative analyses without the inherent liabilities of a randomized control trial, such as subject crossover. Furthermore, the PS weighting of investigational and control subjects is performed prior to revealing any outcomes data, solely using preoperative subject demographic data by a statistician blinded to outcomes data to minimize sources of operational bias during subsequent analyses of outcomes.
These clinical 12-month findings demonstrate substantial symptom relief achieved after both TJR and TLIF/PLIF. Safety endpoints—including adverse events, neurological status, and reoperation rates—are being collected prospectively and will be reported at the 24-month primary analysis as part of the premarket approval submission. In the RWE fusion cohort, bone morphogenetic protein and other biologics were not permitted. Because many US surgeons use biologics in TLIF/PLIF, this restriction may limit generalizability.
Conclusions
The findings of the current analysis corroborate and extend the previously reported results from the initial feasibility trial of TJR that showed durable function improvement and pain amelioration through 24 months of follow-up.10,28 Compared with patients treated in the RWE study, patients undergoing lumbar TJR in the current study experienced a significantly greater overall decrease in ODI scores through 12 months of postoperative follow-up. Longer-term follow-up with complete clinical and radiographic evaluation is necessary to confirm the safety and effectiveness of posterior lumbar decompression and dynamic stabilization with TJR.
Acknowledgments
The authors appreciate the thorough text review by Ronald Yarbrough and the data management and statistical support provided by David Maislin and Alex Breno (Biomedical Statistical Consulting, Philadelphia, PA, USA).
Footnotes
Funding Financial support for the research, authorship, and/or publication of this article was provided by 3Spine (Chattanooga, TN, USA).
Declaration of Conflicting Interests Jeffrey A. Goldstein, J. Alex Sielatycki, S. Craig Humphreys, and Scott D. Hodges have stock in 3Spine. Additionally, Pierce D. Nunley reports a research grant from Orthofix, and participation on an advisory board from 3Spine. J. Alex Sielatycki reports consulting fees from Synergy Spinal Solutions. Scott D. Hodges is an employee of 3Spine. Jon E. Block reports consulting fees from 3Spine and participation on an advisory board from 3Spine. Domagoj Coric reports royalties/licenses from Spine Wave, Acellus, Medtronic, and Globus; consulting fees from Spine Wave, Medtronic, and Globus; payment/honoraria from Spinal Elements; support for attending meetings/travel from Spinal Elements, Medtronic, and Globus; serving on the AANS Board of Delegates; and stock/stock options for Spine Wave, Premia Spine, and 3Spine. Jeffrey A. Goldstein reports a research grant from 3Spine, royalties/licenses from Globus Medical and Xtant, consulting fees from 3Spine and Globus Medical, support for attending meetings from 3Spine, and participation on an advisory board from 3Spine.
- This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery. Copyright © 2025 ISASS. To see more or order reprints or permissions, see http://ijssurgery.com.
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