Faculty Bibliography

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.

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.

Study DesignCross-sectional survey.ObjectivesTo determine the prevalence and predictors of incidental durotomy (ID) among AO Spine surgeons globally, and assess current management strategies and associated complications.MethodsAn electronic questionnaire was distributed to 937 AO Spine surgeon members in October-November 2024, to collect data on surgeon demographics, work characteristics, experience with ID, and preferred management techniques. Logistic regression identified predictors of frequent IDs (>5% of surgeries). Significance was set at P ≤ 0.05.ResultsSurgeons reported ID frequencies ranging from 1% to >20%. Overall, 12% reported frequent IDs. Longer surgical experience (OR = 0.406, P = 0.031) was protective, while working in a public/ governmental hospital (OR = 1.775, P = 0.023) was a risk factor. Medium-sized IDs (1-10 mm) were most common in lumbar surgery (52.2%). Sutures and sealants were commonly used for medium and large tears. Prolene sutures (76.5%) and autologous grafts (53.8%) were preferred. Subfascial drains without suction were frequently used. Management of large and medium tears commonly included 48 and 24 hours of bed rest, respectively. Immediate ambulation was most frequent for small tears. Most surgeons (79.2%) reported occasional or rare complications from dural tears, with a significant association with dural graft repair (OR = 1.946,P < 0.001). Disclosure of IDs to patients was nearly universal (97.3%).ConclusionThe study highlights the frequency with which incidental durotomy occurs globally during spinal surgery. Longer surgical experience was a protective factor of frequent ID, while working in a public/ governmental hospital was a risk factor. Standardized protocols for small tears or guidelines for deciding between repair and non-repair are recommended.

PURPOSE/OBJECTIVE:To compare 0.55 T and 3 T MRI for imaging patients with titanium total hip arthroplasty (THA). Patients with orthopedic metallic implants often require diagnostic imaging to evaluate adjacent tissues. MRI performance measures, including artifact levels and SNR, vary with field strength. METHODS:Six patients with titanium THA were scanned with similar protocols at 0.55 T and 3 T, including proton density (PD) weighted turbo spin echo (TSE), PD TSE with view-angle tilting (TSE + VAT), PD slice encoding for metal artifact correction (SEMAC), and short tau inversion recovery with SEMAC (STIR-SEMAC). Images from both field strengths were scored by two readers and qualitatively and quantitatively compared. RESULTS:Diagnostic confidence was significantly higher at 0.55 T compared to 3 T. Perceived metal artifact was substantially reduced at 0.55 T compared to 3 T. At 0.55 T, diagnostic imaging was achieved both without and with multi spectral imaging (MSI) for PD weighted images. CONCLUSION/CONCLUSIONS:Compared to 3 T, 0.55 T MRI offers substantially reduced metal artifacts and higher diagnostic confidence when imaging titanium THA. Advanced multi-spectral techniques may not be required when the metallic components are entirely titanium.

Study DesignLiterature review.ObjectiveTo provide a concise review of outcomes of decompression and fusion (D + F) vs decompression (D) alone for degenerative lumbar spondylolisthesis (DLS).Methods6 articles were selected, including 3 randomized clinical trials (RCT), 2 meta-analyses, and 1 radiographic cohort study. Summarized factors affecting the outcomes of D + F vs D alone for DLS and provide expert level clinical recommendations.ResultsGhogawala included DLS patients showing improved SF-36 scores (P = 0.046) and lower re-operation rates (P = 0.05) in D + F patients compared to D alone. Forsth, included patients with stenosis both with and without DLS, and showed no difference in any reported outcome measure or reoperation rate. Austevoll included DLS patients that found that D alone was non-inferior to D + F in the primary outcome measure of ODI reduction at 2-year after surgery. Gadjradi included studies showing higher morbidity in the D + F group, as compared to D alone. Shukla included studies which found there was no difference in the raw patient outcome scores at final follow-up. Blumenthal included DLS patients who received D and reported disc height of >6.5 mm, facet angle >50°, and dynamic motion >1.25 mm were associated with high re-operation rates (45%, 39%, and 54% respectively).ConclusionsThe RCT's and meta-analyses report contradictory conclusions and no blanket statement regarding the efficacy of D + F vs D alone can be made for all patients with DLS. Surgeons should closely review pre-operative imaging for signs of instability in order to better identify appropriate patients for each indication.

Study DesignSystematic review.ObjectiveThe current literature suggests that decompression-only procedures may be an adequate treatment option for low-grade degenerative spondylolisthesis. It is necessary to understand the causes of the failure to adequately select patients to achieve acceptable results. Our aim is to identify factors associated with failure of decompression-only procedures for degenerative lumbar spondylolisthesis.MethodsAn independent systematic review of scientific databases (PubMed, Scopus, clinicaltrials. gov, Web of Science) was performed to identify relevant articles as per the preferred reporting in systematic reviews and meta-analysis (PRISMA) guidelines. Studies analysing the risk factors for failure following decompression-only procedure for degenerative lumbar spondylolisthesis were included. The pooled analysis was performed using the Stata software.ResultsSix studies were included with the baseline characteristics of the successful group and the failed group. Individual study analysis has found factors like motion at index level, and multi-level decompression to be responsible for failure. However, upon pooled analysis patient-related factors (age, sex, BMI), disease-related factors (Pfirrmann grade, slip distance, disc height, facet angulation, translation, movement at index level, sacral slope), and outcome parameters (VAS, ODI and JOA score) between the two groups did not demonstrate any significant difference.ConclusionHigh-quality evidence analysing the risk factors for failure of decompression-only procedure for degenerative spondylolisthesis is limited. Although factors such as motion at index level, and multi-level decompression were found to be potential risk factors in individual studies, pooled analysis did not find any of them to significantly predict failure of decompression-only procedures for degenerative spondylolisthesis.

BACKGROUND/UNASSIGNED:The concept of spinal instability has been the subject of research since the 1940s and is commonly used in clinical practice to decide on patient treatment. This is despite the lack of an adequately validated diagnostic test for instability. Our goal is to describe automated tests to detect segmental translational and vertical instabilities that can be obtained from lumbar flexion-extension radiographs. We also assess the prevalence of these instabilities in different patient populations. METHODS/UNASSIGNED:Using fully automated methods: (I) flexion-extension studies of asymptomatic volunteers were analyzed to understand the performance of instability metrics in that population; (II) 7,621 lumbar spine flexion-extension from multiple clinical studies were analyzed to document the prevalence of sagittal plane translational and vertical instabilities, corrected for the amount of intervertebral rotation, across different patient populations. RESULTS/UNASSIGNED:Translational or vertical motion abnormalities were rare (<4% of levels) in the asymptomatic population, and the magnitude of translational motion was associated with radiographic disc degeneration (P<0.0001). Sagittal plane translational instabilities were uncommon (<4% of treatment levels) in lumbar disc arthroplasty and biologic disc treatment patients. They were more common (11% to 16% of treatment levels) in lumbar stenosis, lumbar fusion, and dynamic stabilization patients. A higher prevalence of vertical instabilities (27% to 48% of treatment levels) was seen in patients treated for lumbar stenosis and those selected for fusion or dynamic stabilization than those enrolled in disc arthroplasty studies or studies investigating biologics for disc disease treatment (6% to 11% of treatment levels). CONCLUSIONS/UNASSIGNED:New and fully automated approaches to detecting abnormal sagittal plane intervertebral motion may lead to enhanced and standardized diagnosis of lumbar spine instability. Further clinical research is imperative to verify prevalences and validate the efficacy of these metrics in diagnosis and treatment algorithms. If supported by additional research, these metrics may help determine, for example, which lumbar spinal stenosis patients require fusion in addition to decompression surgery.