Faculty Bibliography

STUDY DESIGN/UNASSIGNED:Systematic review. OBJECTIVES/UNASSIGNED:To systematically review, critically appraise and synthesize evidence on use of stem cells from autologous stem cells from bone marrow aspirate, adipose, or any other autologous sources for fusion in the cervical spine compared with other graft materials. METHODS/UNASSIGNED:A systematic search of PubMed/MEDLINE was conducted for literature published through October 31, 2018 and through February 20, 2020 for EMBASE and ClinicalTrials.gov comparing autologous cell sources for cervical spine fusion to other graft options. RESULTS/UNASSIGNED:From 36 potentially relevant citations identified, 10 studies on cervical fusion met the inclusion criteria set a priori. Two retrospective cohort studies, one comparing cancellous bone marrow (CBM) versus hydroxyapatite (HA) and the other bone marrow aspirate (BMA) combined with autograft and HA versus autograft and HA alone, were identified. No statistical differences were seen between groups in either study for improvement in function, symptoms, or fusion; however, in the study evaluating BMA, the authors reported a statistically greater fusion rate and probability of fusion over time in the BMA versus the non-BMA group. Across case series evaluating BMA, authors reported improved function and pain and fusion ranged from 84% to 100% across the studies. In general, complications were poorly reported. CONCLUSIONS/UNASSIGNED:The overall quality (strength) of evidence of effectiveness and safety of autologous BMA for cervical arthrodesis in the current available literature was very low. Based on currently available data, firm conclusions regarding the effectiveness or safety of BMA in cervical fusions cannot be made.

STUDY DESIGN/UNASSIGNED:Retrospective cohort study. OBJECTIVES/UNASSIGNED:The impact of modifiable risk factors (MRFs) on complications, costs, and readmission rates at 30, 90, and 180-days following lumbar spine fusion. METHODS/UNASSIGNED:Patients with lumbar spine fusions within the 2016-2017 Nationwide Readmissions Database (NRD). Patients were stratified by the following MRFs: Alcohol use, tobacco/nicotine use, nutritional malnourishment, dyslipidemia, and primary hypertension. Differences in complications, non-elective readmission rates, costs, and length of stay were compared between MRFs and the non-MRF group. Statistical analysis was conducted using Tukey multiple comparisons of means, 1-way ANOVA, Wald testing, unpaired Welch 2-sample t-tests, multivariate analysis, and predictive modeling. RESULTS/UNASSIGNED:<0.001). CONCLUSIONS/UNASSIGNED:These findings highlight the negative impact each MRF has on patients following lumbar spinal fusion. Further longitudinal research is necessary to comprehensively characterize the effects of various MRFs on spine surgery outcomes.

Background/UNASSIGNED:Modifiable risk factors (MRFs) represent patient variables associated with increased complication rates that may be prevented. There exists a paucity of studies that comprehensively analyze MRF subgroups and their independent association with postoperative complications in patients undergoing cervical spine surgery. Therefore, the purpose of this study is to compare outcomes between patients receiving cervical spine surgery with reported MRFs. Methods/UNASSIGNED:Retrospective analysis of the Nationwide Readmissions Database (NRD) from the years 2016 and 2017, a publicly available and purchasable data source, to include adult patients undergoing cervical fusion. MRF cohorts were separated into three categories: substance abuse (alcohol, tobacco/nicotine, opioid abuse); vascular disease (hypertension, dyslipidemia); and dietary factors (malnutrition, obesity). Three-way nearest-neighbor propensity score matching for demographics, hospital, and surgical characteristics was implemented. Findings/UNASSIGNED: = 0.0037). However, those with substance abuse had the highest readmission rate and were more commonly readmitted for delayed procedure-related infections. Interpretation/UNASSIGNED:A large proportion of patients who receive cervical spine surgery have potential MRFs that uniquely influence their postoperative outcomes. A thorough understanding of patient-specific MRF subgroups allows for improved preoperative risk stratification, tailored patient counseling, and postoperative management planning. Funding/UNASSIGNED:None.

OBJECTIVE:To evaluate the use of guidelines for lumbar spine fusions among spine surgeons in North America. METHODS:An anonymous survey was electronically sent to all AO Spine North America members. Survey respondents were asked to indicate their opinion surrounding the suitability of instrumented fusion in a variety of clinical scenarios. Fusion indications in accordance with North America Spine Society (NASS) guidelines for lumbar fusion were considered NASS-concordant answers. Respondents were considered to have a NASS-concordant approach if ≥ 70% (13 of 18) of their answers were NASS-concordant answers. Comparisons were performed using bivariable statistics. RESULTS:A total of 105 responses were entered with complete data available on 70. Sixty percent of the respondents (n = 42) were considered compliant with NASS guidelines. NASS-discordant responses did not differ between surgeons who stated that they include the NASS guidelines in their decision-making algorithm (5.10 ± 1.96) and those that did not (4.68 ± 2.09) (p = 0.395). The greatest number of NASS-discordant answers in the United States. was in the South (5.75 ± 2.09), with the lowest number in the Northeast (3.84 ± 1.70) (p < 0.01). For 5 survey items, rates of NASS-discordant answers were ≥ 40%, with the greatest number of NASS-discordant responses observed in relation to indications for fusion in spinal deformity (80%). Spine surgeons utilizing a NASS-concordant approach had a significant lower number of NASS-discordant answers for synovial cysts (p = 0.03), axial low back pain (p < 0.01), adjacent level disease (p < 0.01), recurrent stenosis (p < 0.01), recurrent disc herniation (p = 0.01), and foraminal stenosis (p < 0.01). CONCLUSION/CONCLUSIONS:This study serves an important role in clarifying the rates of uptake of clinical practice guidelines in spine surgery as well as to identify barriers to their implementation.

STUDY DESIGN/UNASSIGNED:Retrospective upright MRI study. OBJECTIVE/UNASSIGNED:To validate the presence of positive and negative nerve root sedimentation signs on multi-positional MRI in the upright position and explore the relationship between negative nerve root sedimentation and gravity. METHODS/UNASSIGNED:T2-weighted axial multi-positional images in the upright position at the intervertebral disc levels from L1-L2 to L4-L5 in 141 patients with non-specific low back pain were retrospectively assessed. A positive sedimentation sign was defined as the absence of nerve root sedimentation or the absence of dorsal conglomeration of nerve roots within the dural sac. A negative sedimentation sign was defined as nerve root sedimentation dorsally or dorso-laterally like a horseshoe. Intra-and inter-observer reliability was evaluated. The relationship between sedimentation sign and dural sac cross-sectional area (CSA), anterior-posterior (AP) diameter was also explored. RESULTS/UNASSIGNED:The kappa value of intra-observer reliability was 0.962 and inter-observer reliability was 0.925. Both positive and negative sedimentation signs did appear at all 4 lumbar levels, including L1/2, L2/3, L3/4 and L4/5. A positive sedimentation sign was associated with significantly decreased dural sac CSA and AP diameter at L2/3, L3/4 or L4/5 level when compared to negative sedimentation sign. CONCLUSIONS/UNASSIGNED:Both negative and positive sedimentation signs appeared at the L1/2, L2/3, L3/4, and L4/5 levels on the upright MRI, which suggested that the presence of nerve roots sedimenting dorsally in patients may not be associated with gravity. Moreover, the current study supports that sedimentation signs on multi-positional MRI images could have the same diagnostic functions as on MRI images.

PURPOSE:To elucidate the effects of bisphosphonates on complications following posterior lumbar fusion (PLF) with a large database study. METHODS:The PearlDiver Patient Record Database was queried to identify adult patients who had undergone posterior lumbar fusion (PLF). Those patient cohorts were divided based on a diagnosis of osteoporosis prior to surgery and bisphosphonate usage. This yielded three groups: Osteo+Bisph+, Osteo+Bisph-, and Osteo-Bisph-. The primary outcome of the present study was revision rates at 6 months and 1 year following surgery. Incidence of postoperative complications was analyzed, and statistical analysis was conducted using Pearson chi-square analysis. RESULTS:Patients taking bisphosphonates did not have significantly different rates of revision surgery at 6 months and 1 year, instrumentation complications, or post-vertebral fractures than patients not taking bisphosphonates. Additionally, osteoporotic patients did not have significantly different rates of these complications than patients without osteoporosis. CONCLUSION:Bisphosphonate usage did not significantly affect the rates of postoperative complications following posterior lumbar fusion. Further research is required to fully elucidate the effects of bisphosphonates on outcomes and complications following spine surgery.

STUDY DESIGN/UNASSIGNED:Retrospective database. OBJECTIVES/UNASSIGNED:Although posterior decompression is the most common approach for surgical treatment of degenerative thoracic spine disease, anterior approach is gaining interest due to its advantage in disc visualization. The objective of this study was to compare the intra- and postoperative medical complication rates between anterior and posterior decompression for degenerative thoracic spine pathologies. METHODS/UNASSIGNED:A national US insurance database was queried for patients with degenerative diagnoses who had undergone anterior or posterior thoracic decompression. Incidence of intra- and postoperative complications were evaluated on the day of surgery and within 1 and 3 months. Two subgroups were matched based on age, gender, and comorbidity. The association of decompression approach and complications was assessed using logistic regression. RESULTS/UNASSIGNED:A total of 1459 patients were included, consisting of 1004 patients in posterior and 455 patients in anterior group. Respiratory complications were the most common complications on the day of surgery (8.57%) and within 30 days (17.75%). Matched analysis showed that anterior approach was associated with organ failure, gastrointestinal, and device-/implant-/graft-related complications in all follow-up periods; and with cardiovascular, deep venous thrombosis/pulmonary embolism, and respiratory complications in at least 1 follow-up period. Among respiratory complications, anterior decompression was significantly associated with noninfectious etiologies on the day of surgery (odds ratio [OR] = 1.72), within 30 days (OR = 2.05), and within 90 days (OR = 1.92). CONCLUSIONS/UNASSIGNED:Anterior approach was associated with increased rates of several complications. High rates of respiratory complications necessitate comprehensive preoperative risk stratification to identify those who may benefit more from posterior approach.

STUDY DESIGN/UNASSIGNED:Review. OBJECTIVE/UNASSIGNED:A comparative overview of cost-effectiveness between minimally invasive versus and equivalent open spinal surgeries. METHODS/UNASSIGNED:A literature search using PubMed was performed to identify articles of interest. To maximize the capture of studies in our initial search, we combined variants of the terms "cost," "minimally invasive," "spine," "spinal fusion," "decompression" as either keywords or MeSH terms. PearlDiver database was queried for open and minimally invasive surgery (MIS; endoscopic or percutaneous) reimbursements between Q3 2015 and Q2 2018. RESULTS/UNASSIGNED:In general, MIS techniques appeared to decrease blood loss, shorten hospital lengths of stay, mitigate complications, decrease perioperative pain, and enable quicker return to daily activities when compared to equivalent open surgical techniques. With regard to cost, primarily as a result of these latter benefits, MIS was associated with lower costs of care when compared to equivalent open techniques. However, cost reporting was sparse, and relevant methodology was inconsistent throughout the spine literature. Within the PearlDiver data sets, MIS approaches had lower reimbursements than open approaches for both lumbar posterior fusion and discectomy. CONCLUSIONS/UNASSIGNED:Current data suggests that overall cost-savings may be incurred with use of MIS techniques. However, data reporting on costs lacks in uniformity, making it difficult to formulate any firm conclusions regarding any incremental improvements in cost-effectiveness that may be incurred when utilizing MIS techniques when compared to equivalent open techniques.

STUDY DESIGN/UNASSIGNED:Retrospective comparative study. OBJECTIVES/UNASSIGNED:To compare the perioperative complications of propensity score-matched cohorts of patients with degenerative cervical myelopathy (DCM), who were treated with anterior cervical discectomy and fusion (ACDF), posterior laminectomy with fusion, or laminoplasty. METHODS/UNASSIGNED:The Humana PearlDiver Patient Record Database was queried using the International Classification of Diseases (ICD-9 and ICD-10) and the Current Procedural Terminology (CPT) codes. Propensity score-matched analysis was done using multiple Chi-squared tests with Bonferroni correction of the significance level. RESULTS/UNASSIGNED:< 0.001. CONCLUSIONS/UNASSIGNED:The incidence of dysphagia following laminectomy with fusion was not different compared to ACDF. Postoperative new-onset cervicalgia and revisions were least common in laminoplasty. The highest rate of postoperative limb paralysis was noticed in laminectomy with fusion.

OBJECTIVE: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. METHODS: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. RESULTS: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. CONCLUSIONS: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.