Faculty Bibliography

STUDY DESIGN/METHODS:Retrospective database study. OBJECTIVE:Compare the revision rates of 2-level ACDF, CDR, and hybrid ACDF/CDR. SUMMARY OF BACKGROUND DATA/BACKGROUND:While single-level CDR has been extensively studied, multilevel CDR and hybrid ACDF/CDR constructs have been less well studied. METHODS:This study utilized a large commercial insurance database of patients 65 years old or younger. Patients undergoing 2-level ACDF, 2-level CDR, and hybrid 2-level ACDF/CDR were identified. Patients age 18 years or older with malignant, infectious, or neoplastic etiologies were excluded, as were those undergoing revision surgery or any concomitant posterior cervical surgery. Study follow-up was terminated at 5 years postoperatively. The primary outcome was revision surgery, including anterior and posterior decompression, fusion, and arthroplasty. RESULTS:A total of 99,282 patients were included. The mean age was 51.3 years old (SD 8.1). The mean maximum follow-up was 2.1 years (SD 1.7). In all 3.2% (n=3197) underwent 2-level CDR, 0.5% (n=448) underwent hybrid 2-level ACDF/CDR, and 96.3% (n=95,637) underwent 2-level ACDF. At 5 years postoperatively, in Kaplan-Meier analysis, revision occurred in 10.0% of the CDR group, 12.4% of the hybrid group, and 10.0% of the ACDF group. In multivariable regression analysis, no significant differences in revision occurrence were observed between the CDR, hybrid, and ACDF groups (P<0.15 for all comparisons). In multivariable regression analysis stratified by plate versus stand-alone cage, patients with plated hybrid constructs had higher revision rates than those with both plated ACDF constructs (HR: 1.5, P=0.0387) and 2-level CDR (HR: 1.5, P=0.0477). CONCLUSIONS:In this retrospective database study of patients 65 years old or younger undergoing 2-level anterior cervical surgery, there were no significant differences at 5-year follow-up in revision rates for patients undergoing 2-level CDR, 2-level ACDF, and hybrid ACDF/CDR surgeries. In subanalysis, patients specifically with a plated hybrid ACDF/CDR had a higher occurrence of revision versus those undergoing plated 2-level ACDF or 2-level CDR. Future multicenter, prospective research is necessary to further assess these findings.

BACKGROUND:Enhanced Recovery After Surgery (ERAS) protocols aim to improve recovery, reduce complications, and optimise surgical outcomes. Despite increasing use in spinal surgery, no standardised ERAS for spinal surgery (ERASS) exists and evidence synthesis is limited. This umbrella review consolidates findings from systematic reviews (SRs) and meta-analyses (MAs) to evaluate the clinical and economic impact of ERASS and identify research gaps. METHODS:A systematic search of MEDLINE, Embase, Cochrane Database of Systematic Reviews, and Web of Science (1990-2024) identified SRs and MAs on ERASS. Data extraction followed Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) and Preferred Reporting Items for Overviews of Reviews (PRIOR), with quality assessed using AMSTAR-2 and ROBIS. Overlapping primary studies were removed before recalculating pooled estimates using fixed or random-effects models based on heterogeneity. Primary outcomes included length of stay, postoperative complications, readmission rates, healthcare costs, pain scores, and opioid consumption. RESULTS:Seventeen SRs and 55 MAs (319 primary studies; n=221 605 participants) were included. ERASS significantly reduced length of stay (-1.55 days; 95% confidence interval [CI] -1.83 to -1.27 days; P<0.01), postoperative complications (relative risk=0.61; 95% CI 0.52-0.72; P<0.01), opioid consumption (-7.26 mg morphine equivalents; 95% CI -10.82 to -3.70 mg; P<0.01), and healthcare costs (-$1029.41 per patient; 95% CI -$1630.17 to -$428.65; P<0.01). Readmission rates were not significantly impacted (relative risk=0.91; P=0.38). Pain scores showed a modest, non-significant reduction (-0.27; 95% CI -0.66 to 0.13; P=0.19). High heterogeneity was observed, reflecting protocol and design variation. CONCLUSIONS:ERASS protocols significantly improve surgical efficiency and safety. Standardised guidelines and future research addressing heterogeneity, under-represented ERASS elements, and long-term outcomes are needed. SYSTEMATIC REVIEW PROTOCOL/UNASSIGNED:PROSPERO (CRD42024578786).

BACKGROUND/UNASSIGNED:Interbody fusion has been performed for many decades with evolving strategies and approaches to improve safety, fusion rates, and clinical outcomes. There have been ongoing advancements in the understanding of spinal biomechanics driving improved implant designs. The advent of 3D printing has allowed new concepts of cage designs to become a reality. The purpose of this narrative review is to provide an overview of current and developing technologies in the area of fusion cage design as well as concerns of the impact of marketing versus science in this area. METHODS/UNASSIGNED:A literature search was conducted on PubMed and OVID to identify articles related to interbody fusion cage design. The focus of the review was on current and future interbody fusion cage design. RESULTS/UNASSIGNED:The area of fusion cage design has been rapidly growing. The greatest advancements have been in the area of additive manufacturing which has allowed for much more intricate implant design. Significant advancements have also been made in improving the surfaces of implants to promote osseointegration. Advancements in materials, manufacturing, and sensor technologies are paving the way for developing intelligent interbody fusion cages capable of monitoring fusion progression and potentially stimulating bone growth. CONCLUSION/UNASSIGNED:There have been many exciting developments in the area of fusion cages, primarily related to materials, design, and surface topology, much of which have been driven by the advent of 3D printing. While many of these technologies may hold promise, there is relatively little data for the particular purported benefits of these implants. Much work is needed to understand the mechanobiological function of these devices, their clinical outcomes, indications, and cost-effectiveness.

OBJECTIVE/UNASSIGNED:Lumbar disc herniation (LDH) is one of the most common spine pathologies and its spontaneous regression has been attributed to the activation of immune cells by inflammatory processes and extracellular matrix remodelling. This study aims to identify a macrophage candidate with potential for physiological treatment of LDH. STUDY DESIGN/UNASSIGNED: RESULTS/UNASSIGNED:cells. Additionally, the M2a phenotype presented larger cells and had the highest phagocytic profile towards the explants. CONCLUSIONS/UNASSIGNED:M2a macrophages showed the highest potential towards the design of a macrophage-based therapy for LDH. This study holds great promise for translational medicine aimed at accelerating spontaneous LDH using a physiological treatment that could prevent need for surgical intervention.

STUDY DESIGN/METHODS:Retrospective cohort study. OBJECTIVE:This study explored the association between serum alkaline phosphatase (ALP) and the incidence of pseudoarthrosis, hospital readmission, and return to operating room (ROR) following lumbar spinal arthrodesis. SUMMARY OF BACKGROUND DATA/BACKGROUND:Over the past 2 decades, lumbar spine fusions have increased due to an aging population and surgical advancements, but reoperation rates remain high due to complications like pseudoarthrosis, with elevated alkaline phosphatase (ALP) levels possibly predicting these issues. METHODS:Data on lumbar arthrodesis patients with documented serum ALP levels were obtained from the American College of Surgeons National Quality Improvement Program (ACS-NSQIP) database (2015-2021). Univariate and multivariate models were used to examine the effect of ALP levels on pseudoarthrosis, readmission, and ROR. Further analyses stratified by American Society of Anesthesiologist (ASA) physical status classification. RESULTS:A total of 39,524 patients were included. Elevated ALP was significantly associated with pseudoarthrosis [odds ratio (OR) 1.62, 95% CI 1.03-2.55], readmission (OR 1.78, CI 1.29-2.45), and ROR (OR 2.00, CI 1.37-2.93) in univariate models. Elevated ALP was significantly associated with pseudoarthrosis (OR 1.63, CI 1.03-2.56), readmission (OR 1.65, CI 1.19-2.27), and ROR (OR 1.89, CI 1.27-2.72) in multivariate models. Stratifying by ASA, elevated ALP was associated with pseudoarthrosis (OR 2.60, CI 1.26-5.36) in ASA 2 and ROR (OR 1.78, CI 1.12-2.83) in ASA 3 patients. CONCLUSIONS:Elevated ALP is strongly associated with increased odds of pseudoarthrosis, readmission, and ROR after lumbar spinal arthrodesis and retained a strong association with pseudoarthrosis and ROR after ASA stratification. Conversely, low ALP levels may offer a protective effect against pseudoarthrosis, though not statistically significant. These results may inform surgeons of risks associated with elevated ALP levels before lumbar spine fusion surgery and highlight the importance of comprehensive medical optimization.

Study DesignRetrospective cohort study using a nationally representative inpatient database.ObjectiveTo determine the incidence, timing, and predictors of new-onset psychiatric disorders following lumbar fusion surgery, and to propose a data-driven risk stratification model for early identification and intervention.MethodsWe queried the Nationwide Readmissions Database (2016-2019) to identify adults undergoing elective inpatient lumbar fusion. Patients with preexisting psychiatric diagnoses were excluded. Outcomes included new-onset depression, anxiety, suicidal ideation, and homicidal ideation within 12 months postoperatively. Predictors were assessed using odds ratios. Timing of onset was evaluated with density plots.ResultsAmong 839,576 patients, 12,011 developed depression, 11,828 anxiety, 916 suicidal ideation, and 63 homicidal ideation. Most diagnoses occurred within 90 days postoperatively, with peak incidence around 3 weeks. Opioid use during the index admission significantly increased odds of suicidal ideation (OR 2.13, P = 0.001), anxiety (OR 1.26, P = 0.002), and showed a trend toward depression (OR 1.14, P = 0.087). Medicaid insurance was the strongest predictor of suicidal (OR 3.69) and homicidal ideation (OR 6.41). Female sex and younger age were associated with anxiety and depression; older age was protective against ideation.ConclusionsNew-onset psychiatric disorders are a frequent and early complication following lumbar fusion. Several modifiable and demographic factors - including perioperative opioid use and socioeconomic status - significantly predict risk. These findings underscore the need for structured mental health screening within the first 3 months post-surgery. Implementing a predictive risk stratification tool could enable earlier psychiatric referral, reduce long-term morbidity, and improve both recovery trajectories and overall quality of life.

STUDY DESIGN/SETTING/METHODS:Retrospective Cohort Study. OBJECTIVE:To describe postoperative physical therapy (PostopPT) utilization patterns and evaluate predictors of utilization after anterior cervical discectomy and fusion (ACDF). BACKGROUND CONTEXT/BACKGROUND:ACDF is the most common cervical spine procedure. PostopPT may improve outcomes, but current usage and program characteristics are unknown. METHODS:PearlDiver Database identified patients who underwent ACDF between 2010-April 2023. PostopPT utilization was assessed 7-365 days postoperatively. Demographics, comorbidities, and procedural characteristics were analyzed. Univariate and multivariate logistic regression identified predictors of PostopPT utilization. RESULTS:Of 309,230 ACDF patients, 17.16% utilized PostopPT within one year. Among users, the average number of visits was 7.4, with mean initiation at 88 days (median: 61 d). PostopPT users were younger, had higher comorbidity burden, higher income, were more often female, and more likely to present with combined radiculopathy and myelopathy (P<0.001).Demographic predictors included commercial insurance (OR: 1.37), residence in the Northeast (OR: 1.35) or Midwest (OR: 1.31), income >$75,000 (OR: 1.17), female gender (OR: 1.14), and age <50 (OR: 1.10) (all P<0.001). Comorbidity predictors included fibromyalgia (OR: 1.37), osteoarthritis (OR: 1.30), obesity (OR: 1.29), depression (OR: 1.26), osteoporosis (OR: 1.19), ECI ≥4 (OR: 1.13), diabetes (OR: 1.08), and tobacco use (OR: 1.07) (all P<0.001). Procedural predictors included mixed myelopathy/radiculopathy (OR: 1.29), fusion ≥3 levels (OR: 1.22), orthopedic surgeon as provider (OR: 1.10), inpatient surgery (OR: 1.09), and two-level fusion (OR: 1.08) (all P<0.001).Patients with myelopathy alone were more likely to receive gait training, aquatic therapy, and group training, but less likely to receive manual therapy, electrical stimulation, hot/cold therapy, or ultrasound (all P<0.001). CONCLUSIONS:PostopPT usage following ACDF is limited. Distinct demographic, comorbidity, and procedural factors predicted usage. PostopPT programs varied in timing, frequency, and intervention type.

STUDY DESIGN/METHODS:Retrospective cohort study. OBJECTIVE:To assess the relationship between preoperative HbA1c and postoperative complications up to 180 days in prediabetic and diabetic patients undergoing anterior cervical discectomy and fusion. SUMMARY OF BACKGROUND DATA/BACKGROUND:Diabetes mellitus has been associated with an increased complication rate and poor postoperative outcomes in patients undergoing elective spine surgeries, but few publications have fully analyzed the effect of preoperative HbA1c on postoperative complications in the cervical spine. METHODS:Patients diagnosed with prediabetes or diabetes who underwent anterior cervical discectomy and fusion between 2018 and 2022. Patients were categorized based on their preoperative HbA1c levels: category I with HbA1c levels from 5% to 6.5%, category II from 6.6% to 8%, and category III>8%. Demographics, preoperative glucose and HbA1c levels, and postoperative complications were collected. Postoperative complications were categorized as revision, dysphagia, wound, and other. Pearson χ 2 tests and regression models/analyses were used. RESULTS:The current study included 75 patients. Within 30 days postoperatively, there was 1 patient in category I, 1 in category II, and 2 in category III with documented complications. At 31-90 days, only 1 patient in category III reported a complication. There were no complications 91-180 days postoperatively. There was no statistically significant difference in complication or revision rates among the categories at all postoperative time intervals. CONCLUSIONS:In the current study, no statistically significant difference was found between elevated HbA1c level and complication rates between diabetics categorized by HbA1c levels at all postoperative time intervals. Future studies are necessary to develop a multifactorial approach to medical clearance in diabetic patients that qualify for cervical spine surgeries.