Anterior Lumbar Interbody Fusion Patients Research Articles

One-Level versus Two-Level Anterior Lumbar Interbody Fusion (ALIF) from L4-S1: Comparison of Complications, Alignment, and Patient Outcomes.

Retrospective cohort study. Compare outcomes in patients undergoing one-level or two-level anterior lumbar interbody fusion (ALIF) at L4-S1. Although ALIF may deliver restoration of lumbar lordosis and improvement in clinical outcomes, it also carries risk of complications including major vascular injury. Whether one-level and two-level ALIF offers similar outcomes is not known. Adults who underwent one-level L4-L5 or L5-S1 ALIF and two-level L4-S1 ALIF at a single academic institution were identified. Patient demographics, procedural characteristics, improvement in spinopelvic alignment, and one-year postoperative patient-reported outcome measures (PROMs) and complications were compared. Multivariate regression analyses, accounting for age, gender, and Charlson Comorbidity Index (CCI), were also performed. In total, 158 ALIF patients (111 one-level and 47 two-level) were included, with mean age of 51.4 years, 57.0% female, mean CCI of 1.2, and mean follow-up of 27.0 months. Surgical time (147.3min vs. 124.6min, P=0.002) and hospital length of stay (3.5d vs. 2.9d, P=0.036) were higher for two-level ALIF. One-year postoperatively, two-level ALIF patients had more caudal apex of lordosis (P=0.016) and 4.1mm (P=0.002) and 2.0mm (P=0.019) higher L4-L5 anterior and posterior disc heights, respectively. PROMs were not statistically different across groups (P>0.05). Finally, two-level ALIF patients were 10.9 times more likely to have in-hospital complications (P=0.040), such as intraoperative vascular injury (11.1% vs. 1.5%, P=0.040) or postoperative ileus (7.4% vs. 0.0%, P=0.027), than one-level ALIF patients. In this investigation with greater than one-year follow-up, two-level ALIF in the L4-S1 spine had higher procedural time, length of stay, and approach-related complications than one-level ALIF. Although there were minor improvements in alignment with two-level ALIF, PROMs were comparable with improvements from baseline to last follow-up. These findings may help surgeons carefully weigh the risks and benefits of one- versus two-level ALIF when determining surgical plans for patients. IV.

Restoring L4-S1 Lordosis Shape in Severe Sagittal Deformity: Impact of Correction Techniques on Alignment and Complication Profile

Severe sagittal plane deformity with loss of L4-S1 lordosis is disabling and can be improved through various surgical techniques. However, data is limited on the differing ability of anterior lumbar interbody fusion (ALIF), pedicle subtraction osteotomy (PSO), and transforaminal lumbar interbody fusion (TLIF) to achieve alignment goals in severely malaligned patients. To examine surgical techniques aimed at restoring L4-S1 lordosis in severe adult spinal deformity (ASD). Retrospective review of prospectively collected data. A total of 96 patients who underwent ALIF, PSO, and TLIF were included in this study. The following data were observed for all cases: patient demographics, spinopelvic parameters, complications, and PROMs. Severe ASD patients with preoperative PI-LL >20°, L4-S1 lordosis <30°, and full body radiographs and patient-reported outcome measures (PROMs) at baseline and six-week postoperative visit were included. Patients were grouped into ALIF (1-2 level ALIF at L4-S1), PSO (L4/L5 PSO), and TLIF (1-2 level TLIF at L4-S1). Comparative analyses were performed on demographics, radiographic spinopelvic parameters, complications, and PROMs. Among the 96 included patients, 40 underwent ALIF, 27 underwent PSO, and 29 underwent TLIF. At baseline, cohorts had comparable age, sex, race, Edmonton frailty scores and radiographic spinopelvic parameters (p>0.05). However, PSO was performed more often in revision cases (p<0.001). Following surgery, L4-S1 lordosis correction (p=0.001) was comparable among ALIF and PSO patients and caudal lordotic apex migration (p=0.044) was highest among ALIF patients. PSO patients had higher intraoperative estimated blood loss (p<0.001) and motor deficits (p=0.049), and in-hospital ICU admission (p=0.022) and blood products given (p=0.004) but were otherwise comparable in terms of length of stay, blood transfusion given, and postoperative admission to rehab. Likewise, 90-day postoperative complication profiles and six-week PROMs were comparable as well. ALIF can restore L4-S1 sagittal alignment as powerfully as PSO, with fewer intra-operative and in-hospital complications. When feasible, ALIF is a suitable alternative to PSO and likely superior to TLIF for correcting L4-S1 lordosis among patients with severe sagittal malalignment.

The influence of preoperative Veterans RAND-12 physical composite score in patients undergoing anterior lumbar interbody fusion [Retrospective Review

No study has evaluated the preoperative impact of Veterans RAND-12 Physical Composite Score (VR-12 PCS) on anterior lumbar interbody fusion (ALIF) patients. This study examines its influence on physical function, mental health, pain, and disability outcomes. Two cohorts of ALIF patients with preoperative VR-12 PCS scores were formed using a single-surgeon registry: VR-12 PCS < 30 and VR-12 PCS ≥ 30. Demographics, perioperative characteristics, and patient-reported outcome measures (PROMs) were collected. PROMs of VR-12 PCS/Mental Composite Score (MCS), Short Form-12 (SF-12) PCS/MCS, Patient-Reported Outcomes Measurement Information System-Physical Function (PROMIS-PF), Patient Health Questionnaire-9 (PHQ-9), Visual Analog Scale-Back/Leg Pain (VAS-BP/LP), and Oswestry Disability Index (ODI) were collected pre/postoperatively up to 2-years. Demographics, perioperative characteristics, and preoperative PROMs were compared. Intercohort postoperative 6-week/final PROMs and improvements were compared. Of 80 patients, there were 41 in the VR-12 PCS < 30 cohort. Besides VR-12 PCS, VR-12 PCS < 30 patients reported inferior preoperative VR-12 MCS/SF-12 PCS/PROMIS-PF/PHQ-9/ODI scores (p ≤ 0.003, all). At 6-weeks postoperatively, VR-12 PCS < 30 reported inferior VR-12 PCS/SF-12 PCS/PROMIS-PF/PHQ-9 (p ≤ 0.030, all). There was greater improvement up to 6-weeks postoperatively in VR-12 PCS < 30 for VR-12 PCS/MCS and SF-12 PCS (p ≤ 0.020, all). VR-12 PCS < 30 reported superior improvement by final follow-up in VR-12 PCS/SF-12 PCS/PHQ-9 (p ≤ 0.006, all). MCID achievement rates were higher in VR-12 PCS < 30 for PHQ-9 and ODI (p ≤ 0.013, both). VR-12 PCS < 30 patients reported inferior postoperative physical function, mental health, and disability, yet superior magnitude of improvement in physical function and mental health. Rates of clinically meaningful improvement for VR-12 PCS < 30 were greater in mental health and disability.

Risk Factors for Surgical Site Infections After Single-Level Anterior Lumbar Interbody Fusion.

Abstract Background: Anterior lumbar interbody fusion (ALIF) has become an increasingly popular and effective treatment modality for various conditions of the lumbar spine. However, complications after this procedure can be costly. Surgical site infections (SSIs) are one of these types of complications. The present study identifies independent risk factors for SSI after single-level ALIF to identify high-risk patients better. Patients and Methods: The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was queried to identify single-level ALIF patients from 2005 to 2016. Multilevel fusions and non-anterior approach procedures were excluded. Mann-Pearson χ2 tests analyzed categorical variables, whereas one-way analysis of variance (ANOVA) and independent t-tests analyzed differences in mean values of continuous variables. Risk factors for SSI were identified via a multivariable logistic regression model. A receiver operating characteristic (ROC) curve was generated utilizing the predicted probabilities. Results: A total of 10,017 patients met inclusion criteria; 80 (0.80%) had developed SSI and 9,937 (99.20%) had not. On multivariable logistic regression models, class 3 obesity (p = 0.014), dialysis (p = 0.025), long-term steroid use (p = 0.010), and wound classification 4 (dirty/infected) (p = 0.002) all independently increased the risk for SSI in single-level ALIF. The area under the receiver operating characteristic curve (AUROC; C-statistic) was 0.728 (p < 0.001), indicating relatively strong reliability of the final model. Conclusions: Several independent risk factors including obesity, dialysis, long-term steroid use, and dirty wound classification all increased risk for SSI after single-level ALIF. By identifying these high-risk patients, surgeons and patients can have more informed pre-operative discussions. In addition, identifying and optimizing these patients prior to operative intervention may help to minimize infection risk.

Establishing Minimum Clinically Important Difference Thresholds for Physical Function and Pain in Patients Undergoing Anterior Lumbar Interbody Fusion

To establish minimum clinically important difference (MCID) in anterior lumbar interbody fusion (ALIF) for the physical function patient-reported outcome measures, Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS-PF), 12-Item Short Form (SF-12) physical component score (PCS), Veterans RAND 12 (VR-12) PCS, and pain patient-reported outcome measures visual analog scale (VAS) back and VAS leg through anchor- and distribution-based calculations. Patients undergoing ALIF with preoperative and 6-month Oswestry Disability Index were included. Using Oswestry Disability Index as the anchor, anchor-based calculation methods were the average change, minimum detectable change, and receiver operating characteristic curve methods. Distribution-based methods were the standard error of measurement, reliable change index, effect size, and half of the standard deviation (0.5ΔSD). Fifty-one patients were identified. Anchor-based methods ranged from 2.9 to 11.5 for PROMIS-PF, 8.2-13.6 for SF-12 PCS, 7.8-16.8 for VR-12 PCS, 0.5-3.9 for VAS back, and 1.0-3.4 for VAS leg. The area under curve ranged from 0.59 (VAS back) to 0.78 (VR-12 PCS). Distribution-based methods ranged from 1.0 to 4.2 for PROMIS-PF, 1.8-12.2 for SF-12 PCS, 1.9-6.2 for VR-12 PCS, 0.4-1.6 for VAS back, and 0.5-1.7 for VAS leg. The MCID values greatly relied on the calculation method. The minimum detectable change method was selected as the most appropriate MCID calculation method. The MCID values that may be utilized for ALIF patients are 7.3 for PROMIS-PF, 8.2 for SF-12 PCS, 7.8 for VR-12 PCS, 3.2 for VAS back, and 2.2 for VAS leg.

Recovery ratios and minimum clinically important difference for clinical outcomes in workers’ compensation recipients undergoing MIS-TLIF versus ALIF

There is a scarcity of literature that examines clinical outcomes through patient-reported outcomes (PROs), minimum clinically important difference (MCID), and recovery ratios (RR) for workers' compensation (WC) recipients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) versus anterior lumbar interbody fusion (ALIF). WC claimants undergoing MIS-TLIF versus ALIF were propensity score matched to account for demographic differences. Demographics, perioperative characteristics, and PROs were collected. PROs of Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS-PF), 12-Item Short Form Physical Composite Score (SF-12 PCS), Visual Analog Scale (VAS) back, VAS leg, and Oswestry Disability Index (ODI) were collected at preoperative and postoperative time points. MCID achievement was determined through comparison to values in literature. RR was calculated as the difference between postoperative and preoperative PROs over potential improvement. Comparison between surgical techniques was through non-parametric inferential statistics. Eighty-four WC claimants, with 50 patients undergoing MIS-TLIF, were identified after propensity score matching. ALIF patients had higher estimated blood loss. MIS-TLIF patients had higher postoperative day (POD) 0 VAS pain and POD 0 + 1 narcotic consumption. Patients undergoing either MIS-TLIF or ALIF reported significant improvement in pain and disability. ALIF patients reported significant improvement in physical function. ALIF patients reported superior 1-year PROMIS-PF, 6-week SF-12 PCS, 6-month VAS back, and 12-week VAS leg. No significant differences in MCID achievement rates were noted between cohorts. ALIF patients had higher RR in 6-week and 1-year PROMIS-PF and 6-week SF-12 PCS. Workers' compensation claimants undergoing either MIS-TLIF or ALIF reported significant improvement in pain and disability. ALIF patients reported superior postoperative physical function and pain. ALIF patients had higher recovery ratios in physical function. Workers' compensation claimants undergoing ALIF may experience greater physical function recovery and superior clinical outcomes in physical function and pain.

Single-level Minimally Invasive Transforaminal Lumbar Interbody Fusion Versus Anterior Lumbar Interbody Fusion for the Surgical Treatment of Isthmic Spondylolisthesis.

Limited studies have compared minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) with anterior lumbar interbody fusion (ALIF) for the treatment of isthmic spondylolisthesis. This study aims to compare perioperative variables, patient-reported outcome measures (PROMs), and minimal clinically important difference (MCID) achievement rates between these surgical approaches. Patients with isthmic spondylolisthesis undergoing primary, single-level MIS TLIF or ALIF were identified in a surgical database. Patients were divided into MIS TLIF and ALIF cohorts. Demographics and perioperative characteristics were collected and compared between groups using the chi square test or Student t-test. PROMs including the Patient-Reported Outcomes Measurement Information System Physical Function, 12-Item Short Form Physical Composite Score, visual analog scale (VAS) back, VAS leg, and Oswestry Disability Index were collected at preoperative, 6-, 12-week, 6-month, 1-, and 2-year time points. Mean PROMs were compared using the Student t-test for independent samples. MCID attainment was determined using established values in the literature; achievement rates by grouping were compared using chi square analysis. One hundred seventy-one patients were included, 121 MIS TLIF and 50 ALIF. No demographic differences were observed. Mean surgical times were 139.7 minutes (MIS TLIF) and 165.5 minutes (ALIF) (P < 0.001). No other perioperative differences were observed. Mean estimated blood loss values were 63.8 mL (MIS TLIF) and 73.7 mL (ALIF). Mean postoperative lengths of stay were 43.9 hours (MIS TLIF) and 42.5 hours (ALIF). Mean PROMs did not markedly differ among groups at any time point. MCID attainment was markedly higher among MIS TLIF patients for the Oswestry Disability Index at 6 weeks (P = 0.046) and 12 weeks (P = 0.007), Patient-Reported Outcomes Measurement Information System Physical Function at 12 weeks (P = 0.015), and VAS leg at 6 weeks (P = 0.031) and 12 weeks (P = 0.045). No other notable differences were observed among MCID achievement by grouping. While single-level ALIF demonstrated markedly higher surgical times, other perioperative characteristics and PROMs were comparable among ALIF and MIS TLIF patients. Although MCID achievement rates were generally lower for disability and leg pain among ALIF patients, significance was not reached at 6 months, 1 year, or during the overall postoperative period after fusion.

212. ALIF as a salvage procedure for TLIF pseudarthrosis: a clinical outcome study

<h3>BACKGROUND CONTEXT</h3> Lumbar fusion procedures are at risk for pseudarthrosis as a complication. Despite its relative prevalence, few studies have characterized the clinical efficacy of salvage procedures. <h3>PURPOSE</h3> To characterize clinical outcomes following anterior lumbar interbody fusion (ALIF) as a salvage procedure for pseudarthrosis of transforaminal lumbar interbody fusion (TLIF). <h3>STUDY DESIGN/SETTING</h3> Retrospective. <h3>PATIENT SAMPLE</h3> Thirty-four ALIF patients. <h3>OUTCOME MEASURES</h3> VAS back and leg, ODI, SF-12 PCS, VR-12 PCS. <h3>METHODS</h3> A retrospective review of a surgical database of eligible procedures between November 2010 and June 2020 was performed. Inclusion criteria were as follows: single-level revision ALIF procedures performed at the index level for pseudarthrosis of TLIF. Patients were excluded if procedures were primary or performed for infectious, malignant or traumatic etiologies. Demographic and perioperative characteristics were collected. Additionally, time to revision, rates of 1-year arthrodesis, 6-month pseudarthrosis and postoperative complications were calculated. Radiographic measurements were performed to evaluate sagittal alignment and disc height at the preoperative, immediate postoperative and final postoperative timepoint. Differences between preoperative and final postoperative radiographic measurements were evaluated using a Student's t-test. Visual analog scale (VAS) for back and leg pain, Oswestry Disability Index (ODI), 12-Item Short Form physical composite score (SF-12 PCS and VR-12 PCS) were collected preoperatively and postoperatively. Overall achievement of a minimum clinically important difference (MCID) was calculated using the following established values: 1.2 (VAS Back), 1.6 (VAS leg), 12.8 (ODI), 4.0 (SF-12 PCS). <h3>RESULTS</h3> A total of 34 patients who underwent an ALIF revision procedure at the index level were identified. Mean age was 46.7 years with 81.1% being male and 64.9% obese (body mass index: 30 kg/m²). A total of 83.8% had an ASA < 2 and 75.5% carried a CCI > 1. Mean time from index TLIF to salvage ALIF procedure was 21.3 months. Mean operative time was 135.3 minutes with an average blood loss of 75.0mL and hospital length of stay of 49.5 hours. The majority of procedures were performed at the L5-S1 level (73.5%). Patients demonstrated a one-year arthrodesis rate of 100.0% with 2/34 patients requiring an additional revision procedure at the index level for neuroforaminal bone growth. A total of six postoperative complications were observed with one patient suffering from a mild urinary tract infection, one with acute renal failure, one with a venous thromboembolism, one with altered mental status, and two with fever of unknown origin. Following ALIF salvage, there was a significant increase in segmental lordosis, mean anterior and posterior disc height, as well as average disc height (p≤0.037, all). Mean preoperative outcome scores were 7.2 ± 1.9 for VAS back, 6.8 ± 2.8 for VAS leg, 56.7 ± 16.5 for ODI, and 28.1 ± 10.9 for SF-12 PCS. Clinically relevant improvement of PROMs as measured by MCID achievement rates by one-year were 67.1% for VAS back, 57.1% for VAS leg, 40.0% for ODI and 37.5% for SF-12 PCS. <h3>CONCLUSIONS</h3> Use of ALIF as a salvage procedure at either the L4-5 or L5-S1 level for TLIF pseudoarthrosis demonstrated a high arthrodesis rate at one-year. Patients demonstrated high rates of MCID achievement for back and leg pain, as well as ODI. These results support the use of ALIF as a salvage procedure for failed TLIFs at the L4-5 and L5-S1 levels. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Underweight patients are the highest risk body mass index group for perioperative adverse events following stand-alone anterior lumbar interbody fusion

BACKGROUND CONTEXTPrior studies investigating the association between Body Mass Index (BMI) and patient outcomes following spine surgery have had inconsistent conclusions, likely owing to insufficient power, confounding variables, and varying definitions and cutoffs for BMI categories (eg, underweight, overweight, obese, etc.). Further, few studies have considered outcomes among low BMI cohorts. PURPOSEThe current study analyzes how anterior lumbar interbody fusion (ALIF) perioperative outcomes vary along the BMI spectrum, using World Health Organization (WHO) categories of BMI. STUDY DESIGN/SETTINGA retrospective cohort study. PATIENT SAMPLEPatients undergoing stand-alone one or two-level anterior lumbar interbody fusion (ALIF) found in the 2005–2018 American College of Surgeons National Surgical Quality Improvement Program (NSQIP) databases. OUTCOME MEASURESThirty-day adverse events, hospital readmissions, post-operative infections, and mortality. METHODSStand-alone one or two-level ALIF surgical cases were identified and extracted from the 2005–2018 National Surgical Quality Improvement Program (NSQIP) database. Posterior cases and those primary diagnoses of trauma, tumor, infection, or emergency presentation were excluded. Patients were then binned into WHO guidelines of BMI. The incidence of adverse outcomes within 30-day post-operation was defined. Odds ratios of adverse outcomes, normalized to the average risk of normal-weight subjects (BMI 18.5–24.9 kg/m3), were calculated. Multivariate analysis was then performed controlling for patient factors. RESULTSIn total, 13,710 ALIF patients were included in the study. Incidence of adverse events was elevated in both the underweight (BMI<18.5 kg/m3) and super morbidly obese (>50 kg/m3), however, multivariate risks for adverse events and postoperative infection were elevated for underweight patients beyond those found in any other BMI category. No effect was noted in these identical variables between normal, overweight, obese class 1, or even obese class 2 patients. Multivariate analysis also found overweight patients to show a slightly protective trend against mortality while the super morbidly obese had elevated odds. CONCLUSIONSUnderweight patients are at greater odds of experiencing postoperative adverse events than normal, overweight, obese class 1, or even obese class 2 patients. The present study identifies underweight patients as an at-risk population that should be given additional consideration by health systems and physicians, as is already done for those on the other side of the BMI spectrum.

Supervised Machine Learning for Predicting Length of Stay After Lumbar Arthrodesis: A Comprehensive Artificial Intelligence Approach.

Few studies have evaluated the utility of machine learning techniques to predict and classify outcomes, such as length of stay (LOS), for lumbar fusion patients. Six supervised machine learning algorithms may be able to predict and classify whether a patient will experience a short or long hospital LOS after lumbar fusion surgery with a high degree of accuracy. Data were obtained from the National Surgical Quality Improvement Program between 2009 and 2018. Demographic and comorbidity information was collected for patients who underwent anterior, anterolateral, or lateral transverse process technique arthrodesis procedure; anterior lumbar interbody fusion (ALIF); posterior, posterolateral, or lateral transverse process technique arthrodesis procedure; posterior lumbar interbody fusion/transforaminal lumbar interbody fusion (PLIF/TLIF); and posterior fusion procedure posterior spine fusion (PSF). Machine learning algorithmic analyses were done with the scikit-learn package in Python on a high-performance computing cluster. In the total sample, 85% of patients were used for training the models, whereas the remaining patients were used for testing the models. C-statistic area under the curve and prediction accuracy (PA) were calculated for each of the models to determine their accuracy in correctly classifying the test cases. In total, 12,915 ALIF patients, 27,212 PLIF/TLIF patients, and 23,406 PSF patients were included in the algorithmic analyses. The patient factors most strongly associated with LOS were sex, ethnicity, dialysis, and disseminated cancer. The machine learning algorithms yielded area under the curve values of between 0.673 and 0.752 (PA: 69.6% to 80.1%) for ALIF, 0.673 and 0.729 (PA: 66.0% to 81.3%) for PLIF/TLIF, and 0.698 and 0.749 (PA: 69.9% to 80.4%) for PSF. Machine learning classification algorithms were able to accurately predict long LOS for ALIF, PLIF/TLIF, and PSF patients. Supervised machine learning algorithms may be useful in clinical and administrative settings. These data may additionally help inform predictive analytic models and assist in setting patient expectations. Diagnostic study, retrospective cohort study.

Preoperative Duration of Symptoms Does Not Affect Outcomes of Anterior Lumbar Interbody Fusion.

Previous studies have examined the impact of preoperative duration of symptoms (DOS) on lumbar spinal surgery outcomes although this has not been explored for anterior lumbar interbody fusion (ALIF). To assess the impact of preoperative DOS on patient-reported outcome measures (PROMs) of ALIF with posterior instrumentation. A database was retrospectively reviewed for ALIFs with posterior instrumentation. PROMs recorded at preoperative, 6-wk, 12-wk, 6-mo, and 1-yr postoperative timepoints included Visual Analog Scale back and leg, Oswestry Disability Index, 12-Item Short-Form Physical Component Score (SF-12 PCS), and PROM Information System physical function. Achievement of minimum clinically important difference (MCID) was determined by comparing differences in postoperative PROMs from baseline to established values. Patients were grouped based on preoperative DOS into <1-yr and ≥1-yr groups. Differences in PROMs were compared using a t-test, whereas MCID achievement used a χ2 test. Fifty-three patients were included, with 20 in the <1-yr group and 33 in the ≥1-yr group. The most common diagnosis was isthmic spondylolisthesis. No significant preoperative differences were observed in any PROM. DOS groups demonstrated significantly different scores for SF-12 PCS at 6 wk (P = .049). No significant differences in MCID achievement were observed between groups for any PROM. ALIF patients demonstrated similar levels of pain, disability, and physical function regardless of preoperative DOS, except for back pain and physical function at intermittent timepoints. MCID achievement did not differ based on DOS for all outcome measures.

Multicenter assessment of outcomes and complications associated with transforaminal versus anterior lumbar interbody fusion for fractional curve correction.

Few studies have compared fractional curve correction after long fusion between transforaminal lumbar interbody fusion (TLIF) and anterior lumbar interbody fusion (ALIF) for adult symptomatic thoracolumbar/lumbar scoliosis (ASLS). The objective of this study was to compare fractional correction, health-related quality of life (HRQL), and complications associated with L4-S1 TLIF versus those of ALIF as an operative treatment of ASLS. The authors retrospectively analyzed a prospective multicenter adult spinal deformity database. Inclusion required a fractional curve ≥ 10°, a thoracolumbar/lumbar curve ≥ 30°, index TLIF or ALIF performed at L4-5 and/or L5-S1, and a minimum 2-year follow-up. TLIF and ALIF patients were propensity matched according to the number and type of interbody fusion at L4-S1. Of 135 potentially eligible consecutive patients, 106 (78.5%) achieved the minimum 2-year follow-up (mean ± SD age 60.6 ± 9.3 years, 85% women, 44.3% underwent TLIF, and 55.7% underwent ALIF). Index operations had mean ± SD 12.2 ± 3.6 posterior levels, 86.6% of patients underwent iliac fixation, 67.0% underwent TLIF/ALIF at L4-5, and 84.0% underwent TLIF/ALIF at L5-S1. Compared with TLIF patients, ALIF patients had greater cage height (10.9 ± 2.1 mm for TLIF patients vs 14.5 ± 3.0 mm for ALIF patients, p = 0.001) and lordosis (6.3° ± 1.6° for TLIF patients vs 17.0° ± 9.9° for ALIF patients, p = 0.001) and longer operative duration (6.7 ± 1.5 hours for TLIF patients vs 8.9 ± 2.5 hours for ALIF patients, p < 0.001). In all patients, final alignment improved significantly in terms of the fractional curve (20.2° ± 7.0° to 6.9° ± 5.2°), maximum coronal Cobb angle (55.0° ± 14.8° to 23.9° ± 14.3°), C7 sagittal vertical axis (5.1 ± 6.2 cm to 2.3 ± 5.4 cm), pelvic tilt (24.6° ± 8.1° to 22.7° ± 9.5°), and lumbar lordosis (32.3° ± 18.8° to 51.4° ± 14.1°) (all p < 0.05). Matched analysis demonstrated comparable fractional correction (-13.6° ± 6.7° for TLIF patients vs -13.6° ± 8.1° for ALIF patients, p = 0.982). In all patients, final HRQL improved significantly in terms of Oswestry Disability Index (ODI) score (42.4 ± 16.3 to 24.2 ± 19.9), physical component summary (PCS) score of the 36-item Short-Form Health Survey (32.6 ± 9.3 to 41.3 ± 11.7), and Scoliosis Research Society-22r score (2.9 ± 0.6 to 3.7 ± 0.7) (all p < 0.05). Matched analysis demonstrated worse ODI (30.9 ± 21.1 for TLIF patients vs 17.9 ± 17.1 for ALIF patients, p = 0.017) and PCS (38.3 ± 12.0 for TLIF patients vs 45.3 ± 10.1 for ALIF patients, p = 0.020) scores for TLIF patients at the last follow-up (despite no differences in these parameters at baseline). The rates of total complications were similar (76.6% for TLIF patients vs 71.2% for ALIF patients, p = 0.530), but significantly more TLIF patients had rod fracture (28.6% of TLIF patients vs 7.1% of ALIF patients, p = 0.036). Multiple regression analysis demonstrated that a 1-mm increase in L4-5 TLIF cage height led to a 2.2° reduction in L4 coronal tilt (p = 0.011), and a 1° increase in L5-S1 ALIF cage lordosis led to a 0.4° increase in L5-S1 segmental lordosis (p = 0.045). Operative treatment of ASLS with L4-S1 TLIF versus ALIF demonstrated comparable mean fractional curve correction (66.7% vs 64.8%), despite use of significantly larger, more lordotic ALIF cages. TLIF cage height had a significant impact on leveling L4 coronal tilt, whereas ALIF cage lordosis had a significant impact on restoration of lumbosacral lordosis. The advantages of TLIF may include reduced operative duration and hospitalization; however, associated HRQL was inferior and more rod fractures were detected in the TLIF patients included in this study.

A systematic review and meta-analysis of the clinical efficacy of anterior lumbar interbody fusion in the treatment of orthopedic spondylolisthesis.

Many studies have reported the advantages of anterior lumbar interbody fusion (ALIF), but the technique is associated with many complications involving nerve injury. This meta-analysis compared the outcome indicators associated with 2 fusion methods, namely, ALIF and posterolateral fusion (PLF). The clinical efficacy of ALIF was explored to provide evidence-based data for the determination of surgical methods for treating orthopedic spondylolisthesis. Relevant literatures were retrieved from the CBMdisc, CNKI, PubMed, EBSCO, MEDLINE, Science Direct, and Cochrane databases. Keywords in Chinese and English included spondylolisthesis, spine, surgical treatment, ALIF, and PLF. Data including the visual analogue scale (VAS) score, the Oswestry Disability Index (ODI), time of operation, and fusion rate were collated. According to Cochrane manual, Rev Man 5.3 software was used for analysis. A total of 6 articles were included in this meta-analysis. There were significant differences in intraoperative blood loss [Z=3.34; mean difference (MD) =-142.54; 95% confidence interval (CI): -226.17 to -58.92; P=0.0008] and operation time (Z=5.45; MD =-54.31; 95% CI: -73.83 to -34.79; P<0.00001) between patients in the ALIF group and patients in the PLF group. Significant differences were observed in VAS score (Z=3.55; MD =-1.04; 95% CI: -1.62 to -0.47; P=0.0004) nor ODI score (Z=3.07; MD =-6.33; 95% CI: -10.37 to -2.28; P=0.002) between the ALIF group and the PLF group. Interestingly, there was a significant difference in the hospitalization time between the 2 groups (Z=2.39; MD=-1.48; 95% CI: -2.70 to -0.27; P=0.02). Bone fusion rate was no significantly different between patients in the ALIF group and patients in the PLF group [Z=0.43; odds ratio (OR) =0.42; 95% CI: 0.01 to 21.82; P=0.66]. The results of this meta-analysis confirmed that ALIF can effectively improve the degree of spondylolisthesis, provide superior structural stability, and ensure surgical efficacy.

P83. Fractional curve correction using TLIF vs ALIF in adult scoliosis

<h3>BACKGROUND CONTEXT</h3> Few studies investigate fractional curve correction after long fusion with transforaminal (TLIF) vs anterior lumbar interbody fusion (ALIF) for adult symptomatic thoracolumbar/lumbar scoliosis (ASLS). <h3>PURPOSE</h3> Our objective was to compare fractional correction, health-related quality-of-life (HRQL), and complications associated with L4-S1 TLIF vs ALIF in ASLS operative treatment. <h3>STUDY DESIGN/SETTING</h3> Retrospective review of a prospectively collected multicenter consecutive case registry. <h3>PATIENT SAMPLE</h3> Database enrollment required age ≥18 years, scoliosis ≥20º, sagittal vertical axis (SVA) ≥5cm, pelvic tilt ≥25º, or thoracic kyphosis ≥60º. <h3>OUTCOME MEASURES</h3> Radiographic correction (including L4-S1 fractional curve), HRQL (Oswestry Disability Index [ODI], Short Form-36 [SF-36] scores, Scoliosis Research Society-22 [SRS-22r] scores), and complications. <h3>METHODS</h3> Prospective multicenter data was reviewed. Study inclusion required fractional curve ≥10°, thoracolumbar/lumbar curve ≥30°, index TLIF vs ALIF at L4-L5 and/or L5-S1, and minimum 2-year follow-up. TLIF and ALIF patients were propensity-matched using number and type of interbody fusion at L4-S1. <h3>RESULTS</h3> Of 135 potentially eligible consecutive patients, 106 (78.5%) achieved minimum 2-year follow-up (age=60.6±9.3years, women=85.8%, TLIF=44.3%, ALIF=55.7%). Index operations had 12.2±3.6 posterior levels, iliac fixation=86.8%, and TLIF/ALIF at L4-L5 (67.0%) and L5-S1 (84.0%). ALIF had greater cage height (10.9±2.1 vs 14.5±3.0mm, p=0.001) and lordosis (6.3°±1.6° vs 17.0°±9.9°, p=0.001) and longer operative duration (6.7±1.5 vs 8.9±2.5hrs, p<0.001). Final alignment improved significantly (p<0.05): fractional curve (20.2°±7.0° to 6.9°±5.2°), maximum coronal Cobb (55.0°±14.8° to 23.9°±14.3°), C7-sagittal vertical axis (5.1±6.2 to 2.3±5.4cm), pelvic tilt (24.6°±8.1° to 22.7°±9.5°), and lumbar lordosis (32.3°±18.8° to 51.4°±14.1°). Matched analysis demonstrated comparable fractional correction (TLIF=–13.6°±6.7° vs ALIF=–13.6°±8.1°, p=0.982). Final HRQL improved significantly (p<0.05): ODI (42.4±16.3 to 24.2±19.9), SF-36 Physical Component Summary (PCS, 32.6±9.3 to 41.3±11.7), SRS-22r (2.9±0.6 to 3.7±0.7). Matched analysis demonstrated worse ODI (30.9±21.1 vs 17.9±17.1, p=0.017) and PCS (38.3±12.0 vs 45.3±10.1, p=0.020) for TLIF at last follow-up (despite no difference in these parameters at baseline). Total complication rate per patient was not different (TLIF=76.6% vs ALIF=71.2%, p=0.530), but significantly more TLIF patients had rod fractures (RF) (TLIF=28.6% vs ALIF=7.1%, p=0.036). Multiple regression demonstrated 1-mm increase in L4-L5 TLIF cage height lead to 2.2° reduction in L4 coronal tilt (p=0.011), and 1° increase in L5-S1 ALIF cage lordosis lead to 0.4° increase in L5-S1 segmental lordosis (p=0.045). <h3>CONCLUSIONS</h3> Operative ASLS treatment with L4-S1 TLIF vs ALIF demonstrated comparable fractional curve correction (66.7% vs 64.8%) despite significantly larger, more lordotic ALIF cages. TLIF cage height had significant impact on leveling L4 coronal tilt, whereas ALIF cage lordosis had significant impact on lumbosacral lordosis restoration. Advantages of TLIF may include reduced operative duration; however, associated HRQL was inferior and more RFs were detected in this study. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Supine anterior lumbar interbody fusion versus lateral position oblique lumbar interbody fusion at L5-S1: A comparison of two approaches to the lumbosacral junction

IntroductionAt L5-S1, anterior access can be performed with a supine anterior lumbar interbody fusion (ALIF) or lateral position oblique lumbar interbody fusion (LOLIF). We compared clinical and radiographic features of both approaches. MethodsA retrospective study of L5-S1 ALIF and LOLIF patients (2013–2018) by 3 spine surgeons and a vascular surgeon at our hospital was performed. Inclusion criteria were patients undergoing L5-S1 anterior surgery only without other anterior or lateral fusion levels, and data collected were patient demographics, cage parameters, perioperative variables, and radiographic parameters. 58 patients were included (33 ALIF and 25 LOLIF). ResultsThe average surgical time was 211.94 min for ALIF and 154.86 min for LOLIF (p < 0.001). The average blood loss was 214 ml for ALIF and 74 ml for LOLIF (p < 0.001). The average number of days to solid food was 2.55 for ALIF and 0.8 for LOLIF (p < 0.001). The average anterior L5-S1 disc height increase was 8.52 mm for ALIF and 5.02 mm LOLIF (p = 0.018), and the average posterior L5-S1 disc height increase was 3.34 mm for ALIF and 1.30 mm for LOLIF (p = 0.034). The average L5-S1 segmental lordosis increase was 6.82 degrees for ALIF and 7.63 degrees for LOLIF (p = 0.638). ConclusionThe LOLIF is a feasible option for L5-S1 anterior access compared to ALIF. However, supine ALIF afforded larger cages to be placed, resulting in greater postoperative disc height. There did not appear to be a significant difference in postoperative L5-S1 segmental lordosis between the two approaches.

258. Exploring perioperative complications of anterior lumber interbody fusion in patients with a history of prior abdominal surgery: a retrospective cohort study

258. Exploring perioperative complications of anterior lumber interbody fusion in patients with a history of prior abdominal surgery: a retrospective cohort study

243. Predictors of inpatient admission in the setting of anterior lumbar interbody fusion

BACKGROUND CONTEXT While the anterior lumbar interbody fusion (ALIF) procedure may be amenable to ambulatory surgery, it has been hypothesized that limitations such as the risk of postoperative ileus and vascular complications has hindered transition to the outpatient setting. Identification of independent risk factors predisposing patients to inpatient stays of greater than 24 hours after ALIF may facilitate better postsurgical outcomes, target modifiable risk factors, and assist developing screening tools to transition appropriate patients to the ambulatory surgery center (ASC) setting. PURPOSE The purpose of this study is to identify the most relevant risk factors that predispose patients to ≥ 24-hour admission following ALIF. STUDY DESIGN/SETTING Retrospective PATIENT SAMPLE A total of 135 patients who underwent single or multilevel ALIF. OUTCOME MEASURES Postoperative complications, postoperative fever, blood transfusion, cardiovascular complications, longer inpatient stay METHODS A prospectively maintained surgical registry was reviewed for patients undergoing single or multi-level ALIF between May 2006 and September 2019. Demographics, preoperative diagnosis, perioperative variables, and postoperative complications were evaluated according to their elevation of relative risk (RR) of an inpatient stay ≥ 24 hours. A Poisson regression model evaluated predictors of inpatient stays ≥ 24 hours. A stepwise backward regression model identified risk factors for inpatient admission of greater than or equal to 24 hours. RESULTS A total of 135 patients underwent single or multilevel ALIF. 53% of the cohort was female and 54.8% was ≤50 years of age. Nine (6.7%) patients were discharged in less than 24 hours and 126 remained admitted for ≥24 hours. The average inpatient stay was two days. The most common postoperative complication was a temperature ≥100.4°F (n=5, 3.8%). Other complications included blood transfusions (n=4, 3.0%) and cardiovascular complications (n=3, 2.2%). Bivariate analysis revealed that having a multilevel procedure on L4L5 and either L3L4 or L5S1 (RR=1.07 or 1.09, p=0.003) had the largest RR elevation for an inpatient stay of ≥ 24 hours. Stepwise multivariate analysis of risk factors revealed foraminal stenosis (RR=0.84, P=0.045), degenerative disc disease (RR=1.25, P=0.028), estimated blood loss >50 mL (RR=1.25, P=0.011), and BMI ≥30 kg/m2 (RR=1.16, p=0.030) to be significant predictors for inpatient stays of ≥24 hours. CONCLUSIONS Our study provides an incidence of demographics, perioperative characteristics, and postoperative complications as they pertain to patients undergoing ALIF. This preliminary investigation identified the most relevant risk factors to be considered before appropriately transitioning ALIF procedures to the ASC. Further studies of preoperative characteristics are needed to elucidate ideal ASC ALIF patients. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Anterior lumbar compared to oblique lumbar interbody approaches for multilevel fusions to the sacrum in adults with spinal deformity and degeneration.

In adult spinal deformity and degenerative conditions of the spine, interbody fusion to the sacrum often is performed to enhance arthrodesis, induce lordosis, and alleviate stenosis. Anterior lumbar interbody fusion (ALIF) has traditionally been performed, but minimally invasive oblique lumbar interbody fusion (OLIF) may or may not cause less morbidity because less retraction of the abdominal viscera is required. The authors evaluated whether there was a difference between the results of ALIF and OLIF in multilevel anterior or lateral interbody fusion to the sacrum. Patients from 2013 to 2018 who underwent multilevel ALIF or OLIF to the sacrum were retrospectively studied. Inclusion criteria were adult spinal deformity or degenerative pathology and multilevel ALIF or OLIF to the sacrum. Demographic, implant, perioperative, and radiographic variables were collected. Statistical calculations were performed for significant differences. Data from a total of 127 patients were analyzed (66 OLIF patients and 61 ALIF patients). The mean follow-up times were 27.21 (ALIF) and 24.11 (OLIF) months. The mean surgical time was 251.48 minutes for ALIF patients and 234.48 minutes for OLIF patients (p = 0.154). The mean hospital stay was 7.79 days for ALIF patients and 7.02 days for OLIF patients (p = 0.159). The mean time to being able to eat solid food was 4.03 days for ALIF patients and 1.30 days for OLIF patients (p < 0.001). After excluding patients who had undergone L5-S1 posterior column osteotomy, 54 ALIF patients and 41 OLIF patients were analyzed for L5-S1 radiographic changes. The mean cage height was 14.94 mm for ALIF patients and 13.56 mm for OLIF patients (p = 0.001), and the mean cage lordosis was 15.87° in the ALIF group and 16.81° in the OLIF group (p = 0.278). The mean increases in anterior disc height were 7.34 mm and 4.72 mm for the ALIF and OLIF groups, respectively (p = 0.001), and the mean increases in posterior disc height were 3.35 mm and 1.24 mm (p < 0.001), respectively. The mean change in L5-S1 lordosis was 4.33° for ALIF patients and 4.59° for OLIF patients (p = 0.829). Patients who underwent multilevel OLIF and ALIF to the sacrum had comparable operative times. OLIF was associated with a quicker ileus recovery and less blood loss. At L5-S1, ALIF allowed larger cages to be placed, resulting in a greater disc height change, but there was no significant difference in L5-S1 segmental lordosis.

Predictors of inpatient admission in the setting of anterior lumbar interbody fusion: a Minimally Invasive Spine Study Group (MISSG) investigation.

While the anterior lumbar interbody fusion (ALIF) procedure may be amenable to ambulatory surgery, it has been hypothesized that limitations such as the risk of postoperative ileus and vascular complications have hindered transition of this procedure to the outpatient setting. Identification of independent risk factors predisposing patients to inpatient stays of ≥ 24 hours after ALIF may facilitate better postsurgical outcomes, target modifiable risk factors, and assist in the development of screening tools to transition appropriate patients to the ambulatory surgery center (ASC) setting for this procedure. The purpose of this study was to identify the most relevant risk factors that predispose patients to ≥ 24-hour admission following ALIF. A prospectively maintained surgical registry was reviewed for patients undergoing single ALIF between May 2006 and December 2019. Demographics, preoperative diagnosis, perioperative variables, and postoperative complications were evaluated according to their relative risk (RR) elevation for an inpatient stay of ≥ 24 hours. A Poisson regression model was used to evaluate predictors of inpatient stays of ≥ 24 hours. Risk factors for inpatient admission of ≥ 24 hours were identified with a stepwise backward regression model. A total of 111 patients underwent single-level ALIF (50.9% female and 52.6% male, ≤ 50 years old). Eleven (9.5%) patients were discharged in < 24 hours and 116 remained admitted for ≥ 24 hours. The average inpatient stay was > 2 days (53.7 hours). The most common postoperative complications were fever (body temperature ≥ 100.4°F; n = 4, 3.5%) and blood transfusions (n = 4, 3.5%). Bivariate analysis revealed a preoperative diagnosis of retrolisthesis or lateral listhesis to elevate the RR for an inpatient stay of ≥ 24 hours (RR 1.11, p = 0.001, both diagnoses). Stepwise multivariate analysis demonstrated significant predictors for inpatient stays of ≥ 24 hours to be an operation on L4-5, coexisting degenerative disc disease (DDD) with foraminal stenosis, and herniated nucleus pulposus (RR 1.11, 95% CI 1.03-1.20, p = 0.009, all covariates). This study provides data regarding the incidence of demographic and perioperative characteristics and postoperative complications as they pertain to patients undergoing single-level ALIF. This preliminary investigation identified the most relevant risk factors to be considered before appropriately transitioning ALIF procedures to the ASC. Further studies of preoperative characteristics are needed to elucidate ideal ASC ALIF patients.

Clinical experience with the use of a spherical bioactive glass putty for cervical and lumbar interbody fusion.

A retrospective clinical case series study was conducted to evaluate the use of a novel, spherical bioactive glass bone graft (BioSphere Putty) as a graft material for cervical and lumbar interbody fusion. Data was collected from a single surgeon using BioSphere Putty along with standardized hardware in anterior cervical decompression and fusion (ACDF), transforaminal lumbar interbody fusion (TLIF), and anterior lumbar interbody fusion (ALIF) surgical procedures. BioSphere Putty was used in combination with cancellous allograft (ACDF and ALIF) or in combination with autograft (TLIF). Clinical outcomes were assessed at 1- and 2-year using radiographic imaging and the visual analog pain scale (VAS). VAS scores at the 1- and 2-year follow-up periods were statistically compared to pre-operative scoring. Successful clinical outcomes were determined by a combination of the presence of a complete radiographic fusion and a decrease in VAS at 1-year and 1- and 2-year follow-up periods. The retrospective review of the patient data identified 248 cases that had either 1- or 1- & 2-year follow-up. This consisted of 115 ACDF procedures and 133 lumbar fusion procedures. Lumbar fusion cases were further sub-grouped with 103 patients undergoing TLIF procedures and 30 patients undergoing ALIF procedures. The global results for the series as a whole showed clinical outcomes comparative to other advanced biologic bone grafts. Radiographically all patients demonstrated fusion (100% fusion rate) and there were no clinical adverse events, infections, or graft-related complications in any of the patients in the series. One-year VAS scores were consistent with historical norms and demonstrated significant decreases in pre-operative pain for both ACDF patients (78% decrease) and lumbar patients (66% decrease TLIF/ALIF) (t test, P<0.05). By 2 years, VAS scores continued to drop with significant decreases for the ACDF patients (96%), TLIF patients (82%), and ALIF patients (80%) (t test, P<0.05). VAS scores were also assessed for each individual patient. The data showed a VAS score decrease from pre-operative levels in 93% of the ACDF patients and 89% of the lumbar patients. Combined with the 100% radiographic fusion rate in all patients, this resulted in a in a clinical success rate of 93% for the ACDF patients and 89% for the lumbar patients. The results of this clinical case series demonstrated that BioSphere Putty is a clinically effective and versatile synthetic bone graft material in the spine.