STUDY DESIGN.Prospective, randomized, controlled trial.
OBJECTIVE.To compare arthrodesis rates between patients undergoing a primary single-level minimally invasive transforaminal lumbar interbody ...fusion (MIS TLIF) with either Actifuse or recombinant human bone morphogenetic protein-2 (rhBMP-2).
SUMMARY OF BACKGROUND DATA.Preclinical animal studies suggest that silicate-substituted calcium phosphate (Actifuse) bone graft substitute offers equivalent or an increased fusion rate compared with other graft enhancers/extenders and rhBMP-2.
METHODS.Fifty-two patients undergoing a single-level unilateral MIS TLIF were evenly randomized into 2 cohorts as followsthe Actifuse cohort received Actifuse combined with 5 mL of bone marrow aspirate (n = 26; 50%), whereas the rhBMP cohort received 4.2 mg of rhBMP-2 (n = 26; 50%). A pre hoc G*Power analysis yielded a sample size of n = 26 that was determined through a 2-tailed distribution calculation. Computed tomographic analysis was performed at 6 months and 1 year postoperatively. Pre- and postoperative visual analogue scale scores were obtained to assess the clinical outcomes. Arthrodesis was determined by 2 separate, blinded orthopedic surgeons and a board certified radiologist.
RESULTS.At 1-year follow-up, 65% (17/26) of the Actifuse cohort and 92% (24/26) of the rhBMP-2 cohort demonstrated a radiographical arthrodesis (P = 0.01). In both study cohorts, the 1-year postoperative visual analogue scale scores significantly improved (P < 0.001). Pseudarthrosis rates at 1 year were 35.0% (9/26) and 7.7% (2/26) for the Actifuse and rhBMP-2 groups, respectively (P = 0.01, OR = 6.35, 95% CI = 1.22–33.1). A greater reoperation rate was noted in the Actifuse cohort (35.0%, 9/26) compared with the BMP-2 cohort (7.7%, 2/26; P = 0.01). One patient with BMP-2 also experienced symptomatic neuroforaminal bone growth (3.8%, n = 1/26).
CONCLUSION.Silicate-substituted calcium phosphate was associated with a significantly lower rate of arthrodesis than rhBMP-2 in a MIS TLIF. The patients with pseudarthrosis in both cohorts were all clinically symptomatic with an unimproved visual analogue scale score. Additional analysis of Actifuse and other graft enhancers/extenders are needed prior to the utilization for an MIS TLIF.Level of Evidence2
Abstract Background context The excellent clinical re.sults of five US Federal Drug Administration (FDA) trials approved for cervical total disc replacement (TDR) (Prestige Medtronic Sofamor Danek, ...Memphis, TN, USA, Bryan Medtronic Sofamor Danek, ProDisc-C Synthes, West Chester, PA, USA, Kineflex|C SpinalMotion, Mountain View, CA, USA, and Mobi-C LDR Spine, Austin, TX, USA) have recently been published. In these prospective randomized studies, superiority or equivalency of TDR was claimed, citing an 8.7% (23/265), 9.5% (21/221), 8.5% (9/106), 12.2% (14/115), and 6.2% (5/81) (mean=9.02%) rate of additional related cervical surgical procedures within 2 years in control anterior cervical discectomy and fusion (ACDF) patients, respectively, compared with 1.8% (5/276), 5.8% (14/242), 1.9% (2/103), 11% (15/136), and 1.2% (2/164) (mean=4.34%) in patients receiving the cervical TDR. The rate of reoperation within 2 years after ACDF seems unusually high. Purpose To assess the rate of and specific indications for early reoperation after ACDF in a cohort of patients receiving the ACDF as part of their customary care. These results are contrasted with similar patients receiving ACDF as the control arm of five FDA investigational device exemption (IDE) studies. Study design Multisurgeon retrospective clinical series from a single institution. Patient sample One hundred seventy-six patients with spondylotic radiculopathy or myelopathy underwent ACDF by three surgeons between 2001 and 2005 as part of their clinical practices. All patients had at least 2 years of follow-up with final follow-up within 6 months of completion of this study. Outcome measures Cervical reoperation rates at 2-year follow-up and at 3.5-year follow-up. Methods Review of medical records and telephone conversations were completed to determine the number of patients who had undergone a revision cervical procedure. Results At final follow-up, complete data were available for 159 ACDF patients. Of the 48 patients who underwent single-level ACDF and met criteria for inclusion in the IDE studies, one patient (2.1%) required additional surgery (adjacent-segment degeneration) within 2 years, the duration of follow-up of the five published IDE studies. Of the 159 patients who received single or multilevel ACDF at a mean follow-up of 3.5 years, 12 patients (7.6%) had undergone revision cervical surgery, with three patients (1.9%) undergoing same-level revisions (posterior fusion) and nine patients (5.7%) undergoing adjacent anterior level fusions. Patients who underwent revision same-level surgery typically had the intervention within the first year (mean, 11 months), whereas those requiring adjacent-level fusions typically had surgery later (mean, 29 months). Conclusions The present study identifies a 2.1% rate of repeat surgery within 2 years of a single-level ACDF performed during routine clinical practice, which is lower than that reported in the control arm of the Prestige, ProDisc-C, Bryan, Kineflex|C, and Mobi-C FDA trials (mean=9%). Even with longer follow-up including multilevel cases, our reoperation rate (7.6%) compared favorably with the IDE rates. This discrepancy may reflect different thresholds for reoperation in the control arm of a device IDE study compared with routine clinical practice. Additionally, patients enrolled in the single-level-only IDE trial may have received multilevel procedures outside of the study. This factor could result in a higher rate of subsequent surgeries at adjacent levels not addressed at the index procedure. These data suggest that we need to better understand factors driving treatment and, in particular, decisions to reoperate both in and outside of a device trial.
This was a retrospective cohort study.
This study investigated the influence of preoperative mental health on patient-reported outcome measures (PROMs) and minimal clinically important difference ...(MCID) among workers' compensation (WC) recipients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS TLIF).
No studies have evaluated the impact of preoperative mental functioning on outcomes following MIS TLIF among WC claimants.
WC recipients undergoing single-level MIS TLIF were identified. PROMs of Visual Analog Scale (VAS) for back and leg pain, Oswestry Disability Index (ODI), 12-item Short Form Physical and Mental Composite Scale (SF-12 PCS/MCS), and Patient-Reported Outcomes Measurement Information System Physical Function evaluated subjects preoperatively/postoperatively. Subjects were grouped according to preoperative SF-12 MCS: <41 vs. ≥41. Demographic/perioperative variables, PROMs, and MCID were compared using inferential statistics. Multiple regression was used to account for differences in spinal pathology.
The SF-12 MCS <41 and SF-12 MCS ≥41 groups included 48 and 45 patients, respectively. Significant differences in ΔPROMs were observed at SF-12 MCS at all timepoints, except at 6 months (p≤0.041, all). The SF-12 MCS <41 group had worse preoperative to 6-months SF-12 MCS, 12-weeks/6-months VAS back, 12-week VAS leg, and preoperative to 6-months ODI (p≤0.029, all). The SF-12 MCS <41 group had greater MCID achievement for overall ODI and 6-weeks/1-year/overall SF-12 MCS (p≤0.043, all); the SF-12 MCS ≥41 group had greater attainment for 6-month VAS back (p=0.004).
Poorer mental functioning adversely affected the baseline and intermediate postoperative quality-of-life outcomes pertaining to mental health, back pain, and disability among WC recipients undergoing lumbar fusion. However, outcomes did not differ 1-2 years after surgery. While MCID achievement for pain and physical function was largely unaffected by preoperative mental health score, WC recipients with poorer baseline mental health demonstrated higher rates of overall clinically meaningful improvements for disability and mental health.
Abstract Background context Perioperative visual loss (POVL) is a rare but devastating complication that may follow spinal surgeries. The incidence of POVL after spinal fusion is not well ...characterized during the past decade. Purpose A population-based database was analyzed to characterize the incidence and risk factors for POVL associated with spinal fusion surgery on a national level. Study design This study consisted of a retrospective database analysis. Patient sample A total of 541,485 patients from the Nationwide Inpatient Sample (NIS) database were included in the study. Outcome measures Study outcome measures included incidence of POVL, length of stay (LOS), in-hospital costs, mortality, and POVL risk factors. Methods Data from the NIS were obtained from 2002 to 2009. Patients undergoing spinal fusion for degenerative pathologies were identified. Patient demographics, comorbidities, LOS, costs, and mortality were assessed. Statistical analyses were conducted using an independent t test for discrete variables and the chi-square test for categorical data. Binomial logistic regression was used to identify independent predictors of POVL. A p value of less than or equal to .001 was used to denote statistical significance. No funds were received by any of the authors for production of this study. Results A total of 541,485 spinal fusions were identified in the United States from 2002 to 2009. The overall incidence of POVL was 1.9 events per 10,000 cases. Of patients who had POVL, 56.2% underwent surgery for a diagnosis of spinal deformity. Patients with POVL were significantly younger on average compared with unaffected patients (37.6 years vs. 52.4 years; p<.001). Length of stay and hospital costs doubled for patients with POVL (p<.001). Logistic regression analysis demonstrated that independent predictors of visual loss were deformity surgery (odds ratio OR=6.1), diabetes mellitus with end organ damage (OR=13.1), and paralysis (OR=6.0, p<.001). Conclusions Our findings demonstrated an overall POVL incidence of 1.9 events per 10,000 spinal fusions. Patients undergoing thoracic fusion for deformity correction accounted for the majority of cases of POVL. Despite being a rare complication after spinal fusion, POVL is an adverse event that may not be entirely preventable. Patients undergoing long-segment fusions for deformity and those with certain risk factors should be counseled regarding the risks of POVL.
Retrospective cohort.
To evaluate the validity of established severity thresholds for Neck Disability Index (NDI) among patients undergoing anterior cervical discectomy and fusion (ACDF) or cervical ...disc arthroplasty (CDA).
Few studies have examined the validity of established NDI threshold values among patients undergoing ACDF or CDA.
A surgical database was reviewed to identify patients undergoing cervical spine procedures. Demographics, operative characteristics, comorbidities, NDI, Visual Analog Scale (VAS), and 12-item Short Form (SF-12) physical and mental composite scores (PCS and MCS) were recorded. NDI severity was categorized using previously established threshold values. Improvement from preoperative scores at each postoperative timepoint and convergent validity of NDI was evaluated. Discriminant validity of NDI was evaluated against VAS neck and arm and SF-12 PCS and MCS.
All 290 patients included in the study demonstrated significant improvements from baseline values for all patient-reported outcome measures (PROMs) at all postoperative timepoints (p<0.001) except SF-12 MCS at 2 years (p =0.393). NDI showed a moderate- to-strong correlation (r≥0.419) at most timepoints for VAS neck, VAS arm, SF-12 PCS, and SF-12 MCS (p<0.001, all). NDI severity categories demonstrated significant differences in mean VAS neck, VAS arm, SF-12 PCS, and SF-12 MCS at all timepoints (p<0.001, all). Differences between NDI severity groups were not uniform for all PROMs. VAS neck values demonstrated significant intergroup differences at most timepoints, whereas SF-12 MCS showed significantly different values between most severity groups.
Neck disability is strongly correlated with neck and arm pain, physical function, and mental health and demonstrates worse outcomes with increasing severity. Previously established severity categories may be more applicable to pain than physical function or mental health and may be more uniformly applied preoperatively for cervical spine patients.
Abstract Background context Recent reports of postoperative radiculitis, bone osteolysis, and symptomatic ectopic bone formation after recombinant human bone morphogenetic protein-2 (rhBMP-2) use in ...transforaminal lumbar interbody fusions (TLIFs) are a cause for concern. Purpose To determine the clinical and radiographic complications associated with BMP utilization in a minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) environment. Study design/setting Retrospective clinical case series at a single institution. Patient sample Five hundred seventy-three consecutive patients undergoing an MIS-TLIF. Outcome measures Reoperation rates and total costs associated with complications of rhBMP-2 use and pseudarthrosis. Methods A retrospective review of 610 consecutive patients undergoing an MIS-TLIF (2007–2010) by a single surgeon at our institution was performed (mean age 48.7 years, range 26–82 years). All patients underwent an MIS laminectomy with bilateral facetectomy, single TLIF cage, unilateral pedicle screw fixation, and 12 mg (large kit) or 4.2 mg (small kit) of rhBMP-2. The BMP-2 collagen-soaked sponge was placed anteriorly in the disc space, followed by local bone graft, and then the cage was filled only with local bone and no BMP-2. Patients were evaluated at 6 months and 1 year with computed tomography (CT) scan. Those demonstrating neuroforaminal bone growth, osteolysis/cage migration, or pseudarthrosis were reviewed, and cost data including direct cost/procedure for both index and revision surgeries were collected. Results Of the 573 patients, 10 (1.7%) underwent 15 additional procedures based on recalcitrant radiculopathy and CT evidence of neuroforaminal bone growth, vertebral body osteolysis, and/or cage migration. Thirty-nine patients (6.8%) underwent reoperation for clinically symptomatic pseudarthrosis. Bone overgrowth was associated with nerve impingement and radiculopathy in all 10 patients (small kit, n=9; large kit, n=1). Osteolysis and cage migration occurred in 2 (20%) of these same 10 patients. Average total costs were calculated per procedure ($19,224), and the costs for reoperation equaled $14,785 per encounter for neuroforaminal bone growth and $20,267 for pseudarthrosis. Conclusions Symptomatic ectopic bone formation, vertebral osteolysis, and pseudarthrosis are recognized complications with the use of rhBMP-2 in MIS-TLIFs. Potential causes include improper dosage and a closed space that prevents the egress of the postoperative BMP-2 fluid collection. Management of these complications has a substantial cost for the patient and the surgeon and needs to be considered with the off-label use of rhBMP-2.
A study of the disc height and biochemical changes in the rabbit intervertebral disc after injection of osteogenic protein-1 into the nucleus pulposus.
To evaluate the in vivo effects of osteogenic ...protein-1 administered intradiscally to the intervertebral disc of rabbits.
Growth factors, such as osteogenic protein-1 and transforming growth factor-beta, have the ability to stimulate synthesis of proteoglycan and collagen in vitro. No attempts have yet been made to determine the effects of these growth factors in an in vivo model.
Twenty-four New Zealand adolescent white rabbits were divided evenly into two subject groups. In one group, three consecutive intervertebral discs were injected with saline; whereas in the other group, they were injected with osteogenic protein-1 in saline. At 2, 4, and 8 weeks after the injection, the intervertebral disc heights of the injected specimens were measured by lateral plain radiographs and compared with preinjection measurements. The change in disc height was expressed as the percent disc height index compared with the preinjection value. After the radiographic measurements were obtained, the intervertebral discs were removed and analyzed for DNA, proteoglycan, and collagen contents.
At 2 weeks after the injections, the mean disc height index of the osteogenic protein-1-injected discs was 15% greater than that of the saline group. The increase in disc height with osteogenic protein-1 injection was still statistically significant at the 4- and 8-week time points. The proteoglycan content of the nucleus pulposus in discs injected with osteogenic protein-1 was higher than that in the saline group at the 2-week time point. The osteogenic protein-1-induced effect on the proteoglycan content was also present at the 4- and 8- week time intervals; however, these increases were not statistically significant. There were no significant differences in the DNA content, normalized to noninjected control, of the nucleus pulposus between the saline and osteogenic protein-1 groups. However, a significant increase in the DNA content of the anulus fibrosus in the osteogenic protein-1 group, compared with that of the anulus fibrosus in the saline group, was observed after 4 weeks.
To date, no study has demonstrated the potential in vivo effects of growth factors on the intervertebral disc. The present study reports that the intradiscal administration of osteogenic protein-1 in vivo results in an increased disc height present at 2, 4, and 8 weeks and an increase in PG content of the nucleus pulposus at the 2-week time point. Therefore, osteogenic protein-1 may act to stimulate metabolic activity in the nucleus pulposus. Continued research is needed to evaluate the potential of growth factor-induced reversal of age-related disc degeneration in an appropriate animal model. In addition, studies in a nonhuman primate animal model will be essential before considering intradiscal injection of growth factors in humans.
Abstract Background context Live mesenchymal stem cell (MSC) allograft-containing allogeneic bone grafts have recently gained popularity and currently account for greater than 17% of all bone grafts ...and bone graft substitutes used in spinal surgery. Although the claim of cellular bone matrices containing osteogenic cells with osteoinductive properties is attractive, little is known about their clinical success when used in anterior cervical discectomy and fusion (ACDF). Purpose The objective of this study was to report on the radiographic fusion rates in one- and two-level instrumented ACDF using an MSC. Study design/setting This was a retrospective review of prospectively matched cohort of patients with radiologic assessment of fusion as the primary end point. Patient sample Two matched cohorts of adult patients who underwent ACDF with MSC or standard allograft were included. Outcomes measures The outcome measures included radiographic and clinical evidence of healing at 1 year. Methods A consecutive series of 57 patients who underwent a one- or two-level instrumented ACDF procedure between 2010 and 2012 were retrospectively analyzed. All fusion constructs comprised an interbody allograft, an anterior plate, and Osteocel (NuVasive, San Diego, CA, USA). These patients were matched to a control group of 57 patients. Results Of the 57 cases in both cohorts, 29 (50.9%) were single-level, and 28 (49.1%) were two-level instrumented ACDFs. There were no significant differences in patient age (p=.71), gender, comorbidity burden (Charlson Comorbidity Index CCI: 1.95; 2.42, p=.71) or body mass index (p=.79). At the 1-year follow-up, 50 of 57 (87.7%) patients in the Osteocel cohort demonstrated a solid fusion compared with 54 of 57 (94.7%) in the control group (p=.19). Seven (12.3%) patients in the Osteocel cohort were reported as having a failed fusion at 1 year. Conclusions This is the first non-industry sponsored study to analyze a matched cohort assessing the 1-year arthrodesis rates associated with a nonstructural MSC allograft in one- and two-level ACDF procedures. Although not statistically significant, patients treated with MSC allografts demonstrated lower fusion rates compared with a matched non-MSC cohort.
OBJECTIVEAssess preoperative Patient-Reported Outcomes Measurement Information System (PROMIS) physical function (PF) scores and differences between preoperative and postoperative PROMIS-PF scores ...for patients undergoing anterior cervical discectomy and fusion (ACDF). METHODSAfter Institutional Review Board approval, a prospectively maintained surgical registry was retrospectively reviewed for elective spine surgeries of nontraumatic, degenerative pathology between 2015-2018. Inclusion criteria were primary or revision, single-level ACDF procedures. Multilevel procedures and patients without preoperative surveys were excluded. A preoperative PROMIS score cutoff of 35 divided patients into PROMIS-PF score categories (e.g. , ≥ 35.0, < 35.0). Categorical and continuous variables were evaluated with chi-square tests and t-tests. Linear regression analyzed PROMIS-PF score improvement. RESULTSEighty-six patients were selected, the high and low PROMIS-PF subgroups only differed in mean age (49.1 vs. 41.3, p = 0.002). Significant differences in PROMIS-PF scores were observed among high and low preoperative PROMIS-PF score subgroups at 6 weeks (p = 0.006), 12 weeks (p = 0.006), and 6 months (p = 0.014). Mean differences between preoperative and postoperative PROMIS-PF scores were significantly different between the high and low PROMIS-PF subgroups at 6 weeks (p = 0.041) and 1 year (p = 0.038). A significant negative association was observed between preoperative PROMIS scores and magnitude of improvement at the 6-week postoperative time point (slope = -0.6291, p < 0.001). CONCLUSIONPatients with low preoperative PROMIS-PF scores demonstrated greater improvements at 6 weeks and 1 year. Clinicians should consider patients with low preoperative PROMIS-PF scores to be in the unique position to potentially experience larger postoperative improvement magnitudes than patients with higher preoperative PROMIS-PF scores.
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