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Zorica Buser, Darrel S. Brodke, Jim A. Youssef, Hans-Joerg Meisel, Sue Lynn Myhre, Robin Hashimoto, Jong-Beom Park, S. Tim Yoon, and Jeffrey C. Wang

The purpose of this review was to compare the efficacy and safety of synthetic bone graft substitutes versus autograft or allograft for the treatment of lumbar and cervical spinal degenerative diseases. Multiple major medical reference databases were searched for studies that evaluated spinal fusion using synthetic bone graft substitutes (either alone or with an autograft or allograft) compared with autograft and allograft. Randomized controlled trials (RCT) and cohort studies with more than 10 patients were included. Radiographic fusion, patient-reported outcomes, and functional outcomes were the primary outcomes of interest.

The search yielded 214 citations with 27 studies that met the inclusion criteria. For the patients with lumbar spinal degenerative disease, data from 19 comparative studies were included: 3 RCTs, 12 prospective, and 4 retrospective studies. Hydroxyapatite (HA), HA+collagen, β-tricalcium phosphate (β-TCP), calcium sulfate, or polymethylmethacrylate (PMMA) were used. Overall, there were no differences between the treatment groups in terms of fusion, functional outcomes, or complications, except in 1 study that found higher rates of HA graft absorption.

For the patients with cervical degenerative conditions, data from 8 comparative studies were included: 4 RCTs and 4 cohort studies (1 prospective and 3 retrospective studies). Synthetic grafts included HA, β-TCP/HA, PMMA, and biocompatible osteoconductive polymer (BOP). The PMMA and BOP grafts led to lower fusion rates, and PMMA, HA, and BOP had greater risks of graft fragmentation, settling, and instrumentation problems compared with iliac crest bone graft.

The overall quality of evidence evaluating the potential use and superiority of the synthetic biological materials for lumbar and cervical fusion in this systematic review was low or insufficient, largely due to the high potential for bias and small sample sizes. Thus, definitive conclusions or recommendations regarding the use of these synthetic materials should be made cautiously and within the context of the limitations of the evidence.

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Anthony D'Oro, Mark J. Spoonamore, Jeremiah R. Cohen, Frank L. Acosta, Patrick C. Hsieh, John C. Liu, Thomas C. Chen, Zorica Buser, and Jeffrey C. Wang


The objective of this study was to compare the incidence of degeneration and need for subsequent fusion surgery between patients who were treated nonsurgically and patients treated with fusion after a diagnosis of thoracic-or lumbar-level fracture without degenerative disease.


The authors performed a retrospective study of Orthopedic United Healthcare patients diagnosed with thoracic or lumbar fracture. Patients were filtered into thoracic and lumbar fracture groups using diagnostic codes and then assigned to one of 2 treatment subgroups (fusion surgery or no surgery) on the basis of procedural codes. Disc degeneration and follow-up surgery were recorded. Chi-square statistical analysis was used.


Of 3699 patients diagnosed with a thoracic fracture, 117 (3.2%) underwent thoracic fusion and 3215 (86.9%) were treated nonsurgically. Within 3 years, 147 (4.6%) patients from the nonsurgical subgroup and fewer than 11 (0.9%–8.5%) from the fusion subgroup were diagnosed with thoracic disc degeneration. From the nonsurgical subgroup, 11 (0.3%) patients underwent a thoracic surgery related to disc degeneration compared with zero from the fusion group (p > 0.05). Of 5016 patients diagnosed with lumbar fracture, 150 (3.0%) underwent fusion and 4371 (87.1%) had no surgery. Within 3 years, 503 patients (11.5%) from the nonsurgical subgroup and 35 (23.3%) from the fusion subgroup were diagnosed with lumbar disc degeneration (p < 0.05). From the nonsurgical subgroup, 42 (1.0%) went on to have surgery related to disc degeneration, compared with fewer than 11 (0.7%–6.7%) from the fusion subgroup (values not precise due to privacy limitations).


Fusion surgery for thoracic fracture does not appear to increase the likelihood of undergoing future surgery. In the lumbar region, initial fusion surgery appears to increase the incidence of disc degeneration and could potentially necessitate future surgeries.

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Jeff Ehresman, Daniel Lubelski, Zach Pennington, Bethany Hung, A. Karim Ahmed, Tej D. Azad, Kurt Lehner, James Feghali, Zorica Buser, James Harrop, Jefferson Wilson, Shekar Kurpad, Zoher Ghogawala, and Daniel M. Sciubba


The objective of this study was to evaluate the characteristics and performance of current prediction models in the fields of spine metastasis and degenerative spine disease to create a scoring system that allows direct comparison of the prediction models.


A systematic search of PubMed and Embase was performed to identify relevant studies that included either the proposal of a prediction model or an external validation of a previously proposed prediction model with 1-year outcomes. Characteristics of the original study and discriminative performance of external validations were then assigned points based on thresholds from the overall cohort.


Nine prediction models were included in the spine metastasis category, while 6 prediction models were included in the degenerative spine category. After assigning the proposed utility of prediction model score to the spine metastasis prediction models, only 1 reached the grade of excellent, while 2 were graded as good, 3 as fair, and 3 as poor. Of the 6 included degenerative spine models, 1 reached the excellent grade, while 3 studies were graded as good, 1 as fair, and 1 as poor.


As interest in utilizing predictive analytics in spine surgery increases, there is a concomitant increase in the number of published prediction models that differ in methodology and performance. Prior to applying these models to patient care, these models must be evaluated. To begin addressing this issue, the authors proposed a grading system that compares these models based on various metrics related to their original design as well as internal and external validation. Ultimately, this may hopefully aid clinicians in determining the relative validity and usability of a given model.