Faculty Bibliography

STUDY DESIGN/UNASSIGNED:Systematic review. OBJECTIVES/UNASSIGNED:To systematically review, critically appraise and synthesize evidence on use of autologous stem cells sources for fusion in the lumbar spine. METHODS/UNASSIGNED:A systematic search of PubMed/MEDLINE, EMBASE and ClinicalTrials.gov through February 20, 2020 was conducted comparing autologous cell grafts to other biologics for lumbar spine fusion. The focus was on studies comparing distinct patient groups. RESULTS/UNASSIGNED:From 343 potentially relevant citations, 15 studies met the inclusion criteria set a priori. Seven studies compared distinct patient groups, with BMA being used in combination with allograft or autograft not as a standalone material. No economic evaluations were identified. Most observational studies were at moderately high risk of bias. When used for primary lumbar fusion, no statistical differences in outcomes or complications were seen between BMA+autograft/or +allograft compared to autograft/allograft alone. Compared with allograft, data from a RCT suggested statistically better fusion and lower complication rates with concentrated BMA+allograft. When used in revisions, no differences in outcomes were seen between BMA+allograft and either autograft or rh-BMP-2 but fusion rates were lower with BMA+allograft, leading to additional revision surgery. CONCLUSIONS/UNASSIGNED:There was substantial heterogeneity across studies in patient populations, sample size, biologic combinations, and surgical characteristics making direct comparisons difficult. The overall quality of evidence for fusion rates and the safety of BMA in lumbar fusion procedures was considered very low, with studies being at moderately high or high risk of bias.

STUDY DESIGN:Systematic review. OBJECTIVE:To characterize the effects of postoperative physical therapy (PT) after surgery for cervical spondylosis on patient-reported outcomes and impairments. Secondarily, to identify associated complications, adverse effects, and health care costs with postoperative PT, and to describe the content, timing, and duration of the PT. SUMMARY OF BACKGROUND DATA:Cervical spine surgery is common; however, it is unclear if the addition of postoperative PT leads to improved patient outcomes and decreased health care costs. MATERIALS AND METHODS:PubMed, Embase, Cochrane Central Register of Controlled Trials, Physiotherapy Evidence Database, and Web of Science were searched until July 2019. All peer-reviewed articles involving cervical spine surgery with postoperative PT for cervical spondylosis were considered for inclusion. Risk of bias was assessed using the Revised Cochrane risk-of-bias tool for randomized trials. Findings were described narratively, and GRADE approach was used to define the quality of evidence. RESULTS:A total of 10,743 studies were screened. Six studies met inclusion criteria; 2 randomized controlled trials and 4 subsequent follow-up studies containing study arms that included postoperative PT after cervical spine surgery. Meta-analysis was not performed due to study heterogeneity and no study compared PT+surgery to surgery alone. PT treatment included exercise therapy, cognitive behavioral therapy, and optional vestibular rehabilitation. Included studies indicated PT appeared to have positive effects on patient outcomes, however, there were no treatment control groups and the quality of evidence was very low to low. Timing, duration, and content of PT programs varied. No studies reported complications, adverse effects, or cost-effectiveness relating to PT after surgery. CONCLUSIONS:Current literature prevents a definitive conclusion regarding the impact of postoperative PT, given the lack of treatment control groups. PT treatment was limited to exercise therapy, cognitive behavioral therapy, and optional vestibular rehabilitation in the included studies. PT treatment varied, limiting consistent recommendations for content, timing, and treatment duration. Controlled trials are needed to determine the effectiveness of the addition of postoperative PT following cervical spine surgery for cervical spondylosis. LEVEL OF EVIDENCE:Level II.

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.

LEVEL OF EVIDENCE/METHODS:3.

STUDY DESIGN/UNASSIGNED:Retrospective cross-sectional study. OBJECTIVES/UNASSIGNED:To determine if pre-operative albumin and CRP can predict post-operative infections after lumbar surgery. METHODS/UNASSIGNED:Patients who underwent an anterior lumbar interbody fusion (ALIF), posterior lumbar interbody fusion (PLIF), or lumbar discectomy were identified using a patient record database (PearlDiver) and were included in this retrospective study. Patients were stratified by Charlson Comorbidity Index (CCI) scores and pre-operative albumin and CRP status. Post-operative complications included deep infections and urinary tract infections within 3 months of the surgery and revisions within 1 year of the surgery. RESULTS/UNASSIGNED:74,280 patients were included in this study. 21,903 had pre-operative albumin or CRP lab values. 7,191 (33%), 12,183 (56%), and 2,529 (12%) patients underwent an ALIF, PLIF, and a lumbar discectomy, respectively. 16,191 did not have any complication (74%). The most common complication was UTI (16%). Among all patients, hypoalbuminemia was a significant risk factor for deep infection and UTI after ALIF, deep infection, UTI, and surgical revision after PLIF, and deep infection after lumbar discectomy. Elevated CRP was a significant risk factor for deep infection after ALIF, UTI after PLIF, and deep infection after lumbar discectomy in patients with a CCI ≤ 3. CONCLUSIONS/UNASSIGNED:Pre-operative hypoalbuminemia and elevated CRP were significant risk factors for deep infection, UTI, and/or revision, after ALIF, PLIT, and/or lumbar discectomy. Future studies with a larger population of patients with low albumin and high CRP values are needed to further elaborate on the current findings.

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:This was a retrospective database study. OBJECTIVE:The objective of this study was to investigate preoperative risk factors and incidence of venous thromboembolic events (VTEs) after cervical spine surgery. SUMMARY OF BACKGROUND DATA:VTEs are preventable complications that may occur after spinal procedures. Globally, VTEs account for a major cause of morbidity and mortality. Preoperative risks factors associated with increased VTE incidence after cervical spine surgery have not been well-characterized. MATERIALS AND METHODS:Patients undergoing anterior cervical discectomy and fusion (ACDF); posterior cervical fusion (PCF); discectomy; and decompression from 2007 to 2017 were identified using the PearlDiver Database. International Classification of Diseases (ICD) Ninth and 10th Revision codes were used to identify VTEs at 1 week, 1 month, and 3 months postoperative as well as preoperative risk factors. RESULTS:Risk factors with the highest incidence of VTE at 3 months were primary coagulation disorder [ACDF=7.82%, odds ratio (OR)=3.96; decompression=11.24%, OR=3.03], central venous line (ACDF=5.68%, OR=2.11; PCF=12.58%, OR=2.27; decompression=10.17%, OR=2.80) and extremity paralysis (ACDF=6.59%, OR=2.73; PCF=18.80%, OR=2.99; decompression=11.86, OR=3.74). VTE incidence at 3 months for populations with these risks was significant for all surgery types (P<0.001) with the exception of patients with primary coagulation disorder who underwent PCF. Tobacco use had the lowest VTE incidence for all surgery types. CONCLUSIONS:The total cumulative incidence of VTEs at 3-month follow-up was 3.10%, with the highest incidence of VTEs occurring within the first postoperative week (0.65% at 1 wk, 0.61% at 1 mo, 0.53% at 3 mo for ACDF; 2.56% at 1 wk, 1.93% at 1 mo, 1.45% at 3 mo for PCF; 1.37% at 1 wk, 0.93% at 1 mo, 0.91% at 3 mo for decompression). Several preoperative risk factors were found to be significant predictors for postoperative VTEs and can be used to suggest those at increased risk as well as decrease the incidence of preventable VTEs after cervical spine surgery. LEVEL OF EVIDENCE:Level III.

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.

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.

BACKGROUND:Malignant spinal tumors are common, continually increasing in incidence as a function of improved survival times for patients with cancer. Using predictive analytics and propensity score matching, we evaluated the influence of frailty on postoperative complications compared with age in patients with malignant neoplasms of the lumbar spine. METHODS:We used the Nationwide Readmissions Database from 2016 and 2017 to identify patients with malignant neoplasms of the lumbar spine who received a fusion procedure. Patient frailty was queried using the Johns Hopkins Adjusted Clinical Groups. Propensity score matching for age, sex, Charlson Comorbidity Index, surgical approach, and number of levels fused was implemented between frail and nonfrail patients, identifying 533 frail patients and 538 nonfrail patients. The area under the curve (AUC) of each ROC served as a proxy for model performance. RESULTS:Frail patients reported significantly higher inpatient lengths of stay, costs, infection, posthemorrhagic anemia, and urinary tract infections (P < 0.05). In addition, frail patients were more often discharged to skilled nursing facilities and short-term hospitals compared with nonfrail patients (P < 0.0001). Regression models for mortality (AUC = 0.644), nonroutine discharge (AUC = 0.600), and acute infection (AUC = 0.666) were improved when using frailty as the primary predictor. These models were also improved using frailty when predicting 30-day readmission and 90-day hardware failure. CONCLUSIONS:Frailty demonstrated a significant relationship with increased postoperative patient complications, length of stay, costs, and acute complications in patients receiving fusion following resection of a malignant neoplasm of the lumbar spine region. Frailty demonstrated better predictive validity of outcomes compared with patient age.