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Surgical treatment of herniated lumbar intervertebral disks is a common procedure worldwide. However, recurrent herniated nucleus pulposus (re-HNP) may develop, complicating outcomes and patient management. The purpose of this study was to utilize machine-learning (ML) analytics to predict lumbar re-HNP, whereby a personalized risk prediction can be developed as a clinical tool. A retrospective, single center study was conducted of 2630 consecutive patients that underwent lumbar microdiscectomy (mean follow-up: 22-months). Various preoperative patient pain/disability/functional profiles, imaging parameters, and anthropomorphic/demographic metrics were noted. An Extreme Gradient Boost (XGBoost) classifier was implemented to develop a predictive model identifying patients at risk for re-HNP. The model was exported to a web application software for clinical utility. There were 1608 males and 1022 females, 114 of whom experienced re-HNP. Primary herniations were central (65.8%), paracentral (17.6%), and far lateral (17.1%). The XGBoost algorithm identified multiple re-HNP predictors and was incorporated into an open-access web application software, identifying patients at low or high risk for re-HNP. Preoperative VAS leg, disability, alignment parameters, elevated body mass index, symptom duration, and age were the strongest predictors. Our predictive modeling via an ML approach of our large-scale cohort is the first study, to our knowledge, that has identified significant risk factors for the development of re-HNP after initial lumbar decompression. We developed the re-herniation after decompression (RAD) profile index that has been translated into an online screening tool to identify low–high risk patients for re-HNP. Additional validation is needed for potential global implementation.

The aim of this study was to characterize the educational quality and reliability of YouTube videos related to low back pain (LBP) as well as to identify factors associated with the overall video quality. A review of YouTube was performed using two separate search strings. Video-specific characteristics were analyzed for the first 50 videos of each string. Seventy-seven eligible videos were identified as a result. The mean Journal of the American Medical Association score was 2.25 ± 1.09 (range: 0-4) out of 4. The mean Global Quality Score (GQS) score was 2.29 ± 1.37 (range: 1-4) out of 5. The mean LBP score (LPS) score was 3.83 ± 2.23 (range: 0-11) out of 15. Video power index was a predictor of GQS score (β = 55.78, p = 0.048), whereas the number of likes (β = -2.49, p = 0.047) and view ratio (β = -55.62, p = 0.049) were associated with lower quality scores. Days since initial upload (β = 0.32, p = 0.042) as well as like ratio (β = 0.37, p = 0.019) were independent predictors of higher LPS scores. The results of this study suggest that the overall reliability and educational quality of videos uploaded to YouTube concerning LBP are unsatisfactory. More popular videos demonstrated poorer educational quality than their less popular counterparts. As the prevalence of LBP rises, more accurate and thorough educational videos are necessary to ensure accurate information is available to patients.

Author(s): Mallow, G Michael; Siyaji, Zakariah K; Galbusera, Fabio; Espinoza-Orias, Alejandro A; Giers, Morgan; Lundberg, Hannah; Ames, Christopher; Karppinen, Jaro; Louie, Philip K; Phillips, Frank M; Pourzal, Robin; Schwab, Joseph; Sciubba, Daniel M; Wang, Jeffrey C; Wilke, Hans-Joachim; Williams, Frances MK; Mohiuddin, Shoeb A; Makhni, Melvin C; Shepard, Nicholas A; An, Howard S; Samartzis, Dino

Objective: To determine if personal health of spine surgeons worldwide influences percep-tions, healthcare delivery, and decision-making during the coronavirus disease 2019 (CO-VID-19) pandemic. Methods: A cross-sectional study was performed by distributing a multidimensional survey to spine surgeons worldwide. Questions addressed demographics, impacts and perceptions of COVID-19, and the presence of surgeon comorbidities, which included cancer, cardiac disease, diabetes, obesity, hypertension, respiratory illness, renal disease, and current tobacco use. Multivariate analysis was performed to identify specific comorbidities that influenced various impact measures. Results: Across 7 global regions, 36.8% out of 902 respondents reported a comorbidity, of which hypertension (21.9%) and obesity (15.6%) were the most common. Multivariate analysis noted tobacco users were more likely to continue performing elective surgery during the pandemic (odds ratio [OR], 2.62; 95% confidence interval [CI], 1.46–4.72; p = 0.001) and were less likely to utilize telecommunication (OR, 0.51; 95% CI, 0.31–0.86; p = 0.011), whereas those with hypertension were less likely to warn their patients should the surgeon become infected with COVID-19 (OR, 0.57; 95% CI, 0.37–0.91; p = 0.017). Clinicians with multiple comorbidities were more likely to cite personal health as a current stressor (OR, 1.32; 95% CI, 1.07–1.63; p = 0.009) and perceived their hospital’s management un-favorably (OR, 0.74; 95% CI, 0.60–0.91; p = 0.005). Conclusion: This is the first study to have mapped global variations of personal health of spine surgeons, key in the development for future wellness and patient management initia-tives. This study underscored that spine surgeons worldwide are not immune to comorbidi-ties, and their personal health influences various perceptions, healthcare delivery, and de-cision-making during the COVID-19 pandemic.

This was a retrospective comparative study.To compare the likelihood of approach-related complications for patients undergoing single-level lateral lumbar interbody fusion (LLIF) at L4-L5 to those undergoing the procedure at upper lumbar levels.LLIF has been associated with a number of advantages when compared with traditional interbody fusion techniques. However, potential risks with the approach include vascular or visceral injury, thigh dysesthesias, and lumbar plexus injury. There are concerns of a higher risk of these complications at the L4-L5 level compared with upper lumbar levels.A retrospective cohort review was completed for consecutive patients undergoing single-level LLIF between 2004 and 2019 by a single surgeon. Indication for surgery was symptomatic degenerative lumbar stenosis and/or spondylolisthesis. Patients were divided into 2 cohorts: LLIF at L4-L5 versus a single level between L1 and L4. Baseline characteristics, intraoperative complications, postoperative approach-related neurological symptoms, and patient-reported outcomes were compared and analyzed between the cohorts.A total of 122 were included in analysis, of which 58 underwent LLIF at L4-L5 and 64 underwent LLIF between L1 and L4. There were no visceral or vascular injuries or lumbar plexus injuries in either cohort. There was no significant difference in the rate of postoperative hip pain, anterior thigh dysesthesias, and/or hip flexor weakness between the cohorts (53.5% L4-L5 vs. 37.5% L1-L4; P=0.102). All patients reported complete resolution of these symptoms by 6-month postoperative follow-up.LLIF surgery at the L4-L5 level is associated with a similar infrequent likelihood of approach-related complications and postoperative hip pain, thigh dysesthesias, and hip flexor weakness when compared with upper lumbar level LLIF. Careful patient selection, meticulous use of real-time neuromonitoring, and an understanding of the anatomic location of the lumbar plexus to the working corridor are critical to success.

To assess the reliability and educational quality of YouTube videos related to pediatric scoliosis.In December 2020, searches of "pediatric scoliosis", "idiopathic scoliosis", "scoliosis in children", and "curved spine in children" were conducted using YouTube. The first 50 results of each search were analyzed according to upload source and content. The Journal of the American Medical Association (JAMA) Benchmark Criteria were used to assess reliability (score 0-4), and educational quality was evaluated using the Global Quality Score (GQS; score 0-5) and Pediatric Scoliosis-Specific Score (PSS; score 0-15). Differences in scores based on upload source and content were determined by Analysis of Variance (ANOVA) or Kruskal-Wallis tests. Multivariate linear regressions identified any independent predictors of reliability and educational quality.After eliminating duplicates, 153 videos were analyzed. Videos were viewed 28.5 million times in total, averaging 186,160.3 ± 1,012,485.0 views per video. Physicians (54.2%) and medical sources (19.0%) were the most common upload sources, and content was primarily categorized as disease-specific (50.0%) and patient experience (25.5%). Videos uploaded by patients achieved significantly lower JAMA scores (p = 0.004). Conversely, academic or physician-uploaded videos scored higher on PSS (p = 0.003) and demonstrated a trend towards improved GQS (p = 0.051). Multivariate analysis determined longer video duration predicted higher scores on all measures. However, there were no independent associations between upload source or content and assessment scores.YouTube contains a large repository of videos concerning pediatric scoliosis; however, the reliability and educational quality of these videos were low.V.

Imaging methods of the spine have greatly expanded since 1895, providing anatomical clarity for diagnosis and treatment of the cervical, thoracic, lumbar, and sacral vertebrae. The complex anatomy of the vertebrae and irregular contours and geometry of the spinal elements have influenced the rapid development of more precise imaging modalities. Various advancements to two- and three-dimensional imaging through plain radiographs, computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and EOS imaging along with multiple dimensional views of the spine are continuously optimized. Future developments in imaging may improve the assessment of pedicle screw placement and image definition, reduce radiation, and provide autonomous spinal mapping using artificial intelligence.

This chapter examines the various classification schemes utilized to categorize alignment, assess boney anomalies, and assess disc vitality to identify potential lumbosacral disease and injury. Spinal pathophysiology is often multifactorial. On occasions, the severity of pathology and treatment is clear. In other instances, the pathology is more nuanced, requiring additional clinical and radiographic assessments. These cases have led to the development of multiple imaging-based classification systems in an attempt to identify which patients will respond appropriately to a specific intervention. An understanding of the classification schemes currently utilized is invaluable as it further solidifies their clinical significance and continues to drive research forward.

Objective: To review and highlight the historical and recent advances of imaging in spine surgery and to discuss current applications and future directions. Methods: A PubMed review of the current literature was performed on all relevant articles that examined historical and recent imaging techniques used in spine surgery. Studies were examined for their thoroughness in description of various modalities and applications in current and future management. Results: We reviewed 97 articles that discussed past, present, and future applications for imaging in spine surgery. Although most historical approaches relied heavily upon basic radiography, more recent advances have begun to expand upon advanced modalities, including the integration of more sophisticated equipment and artificial intelligence. Conclusions: Since the days of conventional radiography, various modalities have emerged and become integral components of the spinal surgeon's diagnostic armamentarium. As such, it behooves the practitioner to remain informed on the current trends and potential developments in spinal imaging, as rapid adoption and interpretation of new techniques may make significant differences in patient management and outcomes. Future directions will likely become increasingly sophisticated as the implementation of machine learning, and artificial intelligence has become more commonplace in clinical practice.

BACKGROUND CONTEXT Lumbar microdiscectomy is the most commonly performed surgery for treatment of radicular pain resulting from lumbar disc herniations. A growing body of evidence has demonstrated the clinical benefit compared to nonoperative interventions, including rapid recovery, symptom improvement and high patient satisfaction. Index level fusion following microdiscectomy, however, has not been well addressed in the literature. PURPOSE The purpose of this study was to identify risk factors for index level fusion following single level lumbar microdiscectomy. METHODS Retrospective review of patients undergoing primary single level lumbar microdiscectomy at a single institution with at least 6-month follow-up. Demographics, comorbidities, radiographic parameters and intraoperative variables were assessed. Patients undergoing index level fusion following discectomy were compared to those undergoing discectomy alone using independent t-test and chi square analysis for continuous and categorical variables, respectively. Multivariate analysis was also done using a logistic regression model. Significance was set as p RESULTS A total of 1,805 patients were identified for inclusion in analysis. This included 74 patients with eventual index level fusion and 1731 patients with discectomy alone. The fusion rate following primary lumbar discectomy was 4.1%, which occurred on average at 35.55 months (± 37.55 months). Patient-related risk factors include history of smoking, diabetes mellitus, and obesity (p CONCLUSIONS In a large cohort of patients undergoing lumbar discectomy for herniated nucleus pulposus, the risk of subsequent index level fusion was 4.1%. Potential risk factors for eventual fusion include patient related factors such as smoking, diabetes and obesity, radiographic evidence of spinal instability or coronal deformity, and surgical approach. While reherniation requiring revision discectomy may necessitate the eventual need for fusion, revision discectomy alone may not be an independent risk factor. This is a preliminary study, however, and prospective studies with a larger number of patients with long-term follow-up is necessary to investigate and validate these potential risk factors. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Surgical treatment of herniated lumbar intervertebral disks is a common procedure worldwide. However, recurrent herniated nucleus pulposus (re-HNP) may develop, complicating outcomes and patient management. The purpose of this study was to utilize machine-learning (ML) analytics to predict lumbar re-HNP, whereby a personalized risk prediction can be developed as a clinical tool.A retrospective, single center study was conducted of 2630 consecutive patients that underwent lumbar microdiscectomy (mean follow-up: 22-months). Various preoperative patient pain/disability/functional profiles, imaging parameters, and anthropomorphic/demographic metrics were noted. An Extreme Gradient Boost (XGBoost) classifier was implemented to develop a predictive model identifying patients at risk for re-HNP. The model was exported to a web application software for clinical utility.There were 1608 males and 1022 females, 114 of whom experienced re-HNP. Primary herniations were central (65.8%), paracentral (17.6%), and far lateral (17.1%). The XGBoost algorithm identified multiple re-HNP predictors and was incorporated into an open-access web application software, identifying patients at low or high risk for re-HNP. Preoperative VAS leg, disability, alignment parameters, elevated body mass index, symptom duration, and age were the strongest predictors.Our predictive modeling via an ML approach of our large-scale cohort is the first study, to our knowledge, that has identified significant risk factors for the development of re-HNP after initial lumbar decompression. We developed the re-herniation after decompression (RAD) profile index that has been translated into an online screening tool to identify low-high risk patients for re-HNP. Additional validation is needed for potential global implementation.

Background The COVID-19 pandemic has impacted spine care around the globe. Much uncertainty remains regarding the immediate and long-term future of spine care and education in this COVID-19 era. Study design Cross-sectional, international study of spine surgeons. Methods A multi-dimensional survey was distributed to spine surgeons around the world. A total of 73 questions were asked regarding demographics, COVID-19 observations, personal impact, effect on education, adoption of telemedicine, and anticipated challenges moving forward. Multivariate analysis was performed to assess factors related to likelihood of future conference attendance, future online education, and changes in surgical indications. Results A total of 902 spine surgeons from seven global regions completed the survey. Respondents reported a mean level of overall concern of 3.7 on a scale of one to five. 84.0% reported a decrease in clinical duties, and 67.0% reported a loss in personal income. The 82.5% reported being interested in continuing a high level of online education moving forward. Respondents who personally knew someone who tested positive for COVID-19 were more likely to be unwilling to attend a medical conference 1 year from now (OR: 0.61, 95% CI: [0.39, 0.95], P = .029). The 20.0% reported they plan to pursue an increased degree of nonoperative measures prior to surgery 1 year from now, and respondents with a spouse at home (OR: 3.55, 95% CI: [1.14, 11.08], P = .029) or who spend a large percentage of their time teaching (OR: 1.45, 95% CI: [1.02, 2.07], P = .040) were more likely to adopt this practice. Conclusions The COVID-19 pandemic has had an adverse effect on surgeon teaching, clinical volume, and personal income. In the future, surgeons with family and those personally affected by COVID-19 may be more willing to alter surgical indications and change education and conference plans. Anticipating these changes may help the spine community appropriately plan for future challenges.

BACKGROUND CONTEXT Although anterior cervical discectomy and fusion (ACDF) with interbody spacer and separate plate/screw construct (PLATE) is commonly performed, some have asserted it may be associated with a higher incidence of postoperative dysphagia, increased operative time, malpositioned hardware, higher costs, and adjacent segment impingement. To address these concerns, others have opted to utilize an interbody cage with integrated screws and no plate (CAGE) with good results. PURPOSE This study's purpose was to compare the perioperative and radiographic outcomes between stand-alone and anterior plated 1- and 2-level ACDF. STUDY DESIGN/SETTING Prospective randomized controlled trial. PATIENT SAMPLE All procedures were performed by the senior surgeon between July of 2017 and February 2020. Patients with 1- to 2-level degenerative disease were randomized in a 1:1 ratio into one of two treatment arms consisting of either PLATE or stand-alone CAGE reconstruction. Patients were followed for a minimum of 1 year following surgical intervention. OUTCOME MEASURES Primary endpoints assessed included clinical improvement on patient-reported outcome metrics (PROs), construct integrity, cervical alignment, successful arthrodesis, and subsequent revision surgeries. METHODS Statistical methods included chi-squared with Fisher's exact test for categorical variables and Mann-Whitney U-test or students t-test for continuous variables. The threshold for statistical significance was set to p .05. RESULTS A total of 46 patients were randomized: 12 patients were treated with 1-level PLATE, 12 with 1-level CAGE, 12 with 2-level PLATE, and 10 with 2-level CAGE. For single-level ACDF, arthrodesis was observed in 90% of PLATE and 100% of CAGE patients (p = .305). There were no postoperative differences in PROs with the exception of worse swallow function on SWAL-QOL with PLATE at 6 weeks (71.3 SD:14.1 vs 87.9 SD: 11.1, p = .050) and 6 months (80.5 SD: 9.2 vs 92.1 SD: 7.9, p = .042). Pseudarthrosis requiring revision was observed in one PLATE patient. For two-level ACDF, arthrodesis was observed in 90% of PLATE and 80% of CAGE patients (p = .531). CAGE patients reported worse scores on NDI at 6-weeks (22.0 SD: 13.6 vs 52.0 SD: 25.6, p = .037) and 6-months (12.0 SD: 8.38 vs 39.3 SD: 21.3, p = .017), as well as on VAS Neck (0.96 SD: 0.6 vs 5.5 SD: 3.0, p = .010), but no differences in these parameters were seen at one year. However, swallow function was worse with PLATE on SWAL-QOL at 6 weeks postoperatively (76.54 SD: 7.3 vs 91.34 SD: 8.22, p = .038). There were no differences in the rates of fusion, loss of disc height correction, subsidence, or sagittal parameters between the PLATE and CAGE cohorts for both one- and two-level ACDF. CONCLUSIONS There was a significantly greater incidence of transient (but not long-term) postoperative dysphagia in both the single-level and two-level PLATE cohorts. However, early postoperative outcomes were worse for two-level CAGE in certain patient-reported metrics, while radiographic assessments of cervical sagittal alignment showed few differences. These findings suggest that although anterior instrumentation may be associated with a higher likelihood of dysphagia, it may also be associated with higher short-term stability and improved patient-reported outcomes for two-level fusion until arthrodesis has been established. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT Although frequently used for anterior lumbar interbody fusion (ALIF), concerns regarding the use of recombinant human bone morphogenetic protein 2 (BMP-2) include off-label use, elevated cost and adverse outcomes such as osteolysis. The growing evolution of porous implant technology in promoting osseous integration via ingrowth provides an opportunity for a paradigm shift by relying less on biologic-assisted through-growth and leveraging implant on-growth and in-growth in similar fashion to porous metallic implants used in other orthopedic settings such as hip arthroplasty. PURPOSE This study compared perioperative clinical and radiographic outcomes between patients undergoing ALIF with the assistance of BMP-2 in a nonporous, traditional window interbody cage vs those with no biologic using a minimal-window porous titanium interbody cage. STUDY DESIGN/SETTING Retrospective clinical. PATIENT SAMPLE This study retrospectively examined 75 consecutive patients who underwent 1- or 2-level ALIF between 2014 and 2020 with the use of BMP-2 in a nonporous PEEK cage vs a porous titanium interbody cage and no biologic. All patients had surgery with the senior surgeon and were followed for a minimum follow-up of 6-months postoperatively. OUTCOME MEASURES Patient demographics, comorbidities, postoperative complications, and preoperative, immediate and final postoperative patient-reported outcomes (PROs) were assessed. Rates of reoperation were recorded, and arthrodesis was evaluated using Bridwell radiographic criteria and CT when available. Pre- and postoperative radiographic parameters were evaluated for differences in spinopelvic alignment and correction. METHODS Statistical methods included student's t-test and chi-square for continuous and categorical variables, respectively. Continuous variables were reported as means and standard deviations, and categorical variables as proportions. The threshold for statistical significance was set to p RESULTS Forty-three (13 female, 30 male) and 32 (19 female, 13 male) patients were assessed in the BMP-2 and titanium cage cohorts, respectively. On PRO assessment, baseline VAS leg among BMP-2 patients (6.87, SD: 1.96 vs 5.16, SD: 2.41; p = .023) while the titanium cage group reported worse VAS back scores (6.23, SD: 2.39 vs 7.82, SD: 1.40; p = .023). However, there were no significant differences recorded in postoperative PRO surveys between groups. Correction of spinopelvic alignment was equally maintained between groups at final follow-up when compared to immediate postoperative radiographs. Similarly, disc spaces were equivalently upheld across cohorts, with the exception of greater degeneration among BMP-2 patients at the L4-L5 anterior (-1.78, SD: 3.00 vs -0.07, SD: 2.63; p = .039) and foraminal (-2.34, SD: 3.11 vs -0.07, SD: 2.06; p = .006) disc spaces. Interbody subsidence was similar at the superior (1.13, SD: 0.84 vs 1.28, SD: 0.88; p = .458) and inferior endplates (0.55, SD: 0.79 vs 0.91, SD: 1.27; p = .154), and radiographic evidence of fusion was observed at equivalent rates (90% vs 90.9%, p = .776). There were no differences in the rates of secondary surgeries for adjacent segment disease (ASD) (4.6% vs 0%, p = .222) or index-level revisions (9.1% vs 18.8%, p = .219). CONCLUSIONS Porous titanium interbody cages for ALIF may be equivalent to BMP-2 in nonporous PEEK in achieving arthrodesis, alignment durability and reoperation rates. Although long-term follow-up is necessary, the use of porous titanium implants without external biologics is an intriguing paradigm change which may produce similar outcomes at lower costs. FDA DEVICE/DRUG STATUS Alphatec Identiti Cage (Approved for this indication), Recombinant Human Bone Morphogenetic Protein-2 (Approved for this indication)

BACKGROUND CONTEXT Anterior lumbar interbody fusion (ALIF) has shown significant improvements in clinical outcomes for patients with degenerative disc disease causing lower back pain and foraminal stenosis. However, few studies have examined if there is a difference between outcomes in single level vs two level standalone ALIF. PURPOSE The purpose of this study was to assess for a difference in outcomes in single level vs two-level ALIF. STUDY DESIGN/SETTING Retrospective cohort study of patients treated at a single academic institution by a single surgeon. PATIENT SAMPLE Consecutive adult patients from 2011 to 2019 with the diagnosis of degenerative disc disease who underwent a single level (L5-S1) vs two level (L4-S1) standalone ALIF were included in this study. Only patients with 6 months of follow-up were analyzed. OUTCOME MEASURES Patient demographic data including age, body mass index, gender and American Society of Anesthesiologists classification was collected. Visual analog scale (VAS) pain scores for the back and leg, Oswestry Disability Index (ODI), Short Form 12 (SF-12) and Veterans RAND 12 (VR-12) scores were collected for clinical outcomes preoperatively and at the final postoperative visit. METHODS This study was a retrospective review of prospectively collected data. The patients were divided into cohorts of single level vs level ALIFs. Demographic data was compared between the two cohorts to look for baseline differences. Changes between preoperative and final clinical outcomes were compared using bivariate and multivariate linear regressions. Patients who achieved the minimal clinically important difference (MCID) in VAS and ODI scores from both groups were further analyzed with bivariate and multivariate linear regressions to assess for significant differences in outcomes. RESULTS A total of 73 patients were included. Fifty-six (76.7%) underwent a single level ALIF and 17 (23.3%) underwent two level ALIF. There were no baseline differences in patient demographics, nor in preoperative clinical scores. Both cohorts demonstrated improvements in all clinical outcomes postoperatively, and there was no significant difference between either group in bivariate and multivariate regression analysis of the postoperative clinical outcomes. Twenty patients (35.7%) in the single level ALIF cohort and seven patients (41.2%) in the two-level ALIF groups met the MCID cutoffs in VAS and ODI scores, and there was no significant difference between these patients in outcomes. CONCLUSIONS Both single-level L5-S1 and two-level L4-S1 standalone ALIF for degenerative disc disease demonstrate improvements in all clinical outcomes postoperatively. There is no significant difference between patients who underwent a single-level vs two-level stand-alone ALIF. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT Anterior lumbar interbody fusion (ALIF) is a well-accepted surgical technique for lumbar spondylolisthesis and has been shown to have excellent radiographic and clinical outcomes. ALIF as a treatment for lumbar degenerative disc disease (DDD) is more controversial, with some authors reporting less reliable clinical improvement compared to other pathology. PURPOSE The purpose of this study is to compare the clinical outcomes of L5-S1 ALIF with posterior instrumentation in the setting of isthmic spondylolisthesis (IS) with L5-S1 ALIF for DDD. STUDY DESIGN/SETTING Retrospective cohort study. PATIENT SAMPLE The study included 93 consecutive patients who underwent L5-S1 ALIF without direct posterior decompression for either IS (n=37) or DDD (n=56) identified. All patients who underwent ALIF for IS underwent percutaneous posterior instrumentation, while DDD patients had a stand-alone construct. OUTCOME MEASURES Baseline characteristics including age, sex, body mass index (BMI), and American Society of Anesthesiologists (ASA) physical status classification were reviewed and compared between groups. Preoperative/baseline clinical outcome measures, including visual analog scale (VAS), Short Form 12 (SF-12), Oswestry Disability index (ODI), and Veterans RAND 12 (VR-12), were collected and compared to postoperative measures at a minimum of 6 months. METHODS Changes in outcome measures from preoperative to final postoperative visit were calculated and compared between IS and DDD groups. Proportions of patients who reached minimum clinically important differences (MCID) in VAS and ODI were compared between IS and DDD groups. Bivariate and multivariate logistic regression were used to control for baseline differences in patient characteristics. RESULTS There were no significant differences between IS and DDD groups in terms of age, sex, and ASA score (p>0.05). There was a small, but statistically significant, difference in BMI between IS and DDD groups (27.32 vs 29.99, respectively, p=0.012). There were no significant differences in preoperative VAS-back, VAS-leg, and ODI between IS and DDD groups (p>0.05, Table 2). DDD patients had a lower preoperative SF-12 and VR-12 compared to IS patients (p=0.011 and p=0.01, respectively). At final follow-up, IS patients had better VAS-back, ODI, SF-12, and VR-12 scores compared to DDD patients, with no significant difference in VAS-leg scores. When comparing change from preoperative scores to final follow-up, there were no significant differences in improvement in terms of VAS, ODI, SF-12, and VR-12 between IS and DDD groups. IS and DDD groups had similar proportions of patients who achieved MCID in terms of VAS-back, VAS-leg, and ODI. CONCLUSIONS Although DDD patients have worse preoperative and postoperative clinical measures compared to IS patients, patients with DDD achieve similar levels of clinical improvement after ALIF compared to patients with IS. Additionally, DDD patients were just as likely as IS patients to achieve MCID at final follow-up after ALIF. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.