BACKGROUND CONTEXT Factors driving financial disparities such as operative time and etiology have been explored in other orthopaedic subspecialties but are understudied in spinal deformity surgery. We hypothesized that increased operative time and differing etiology are associated with compensation decrease. PURPOSE To identify factors associated with compensation differences in spinal deformity surgery. STUDY DESIGN/SETTING Retrospective cohort study. PATIENT SAMPLE A total of 31,739 patients. OUTCOME MEASURES Total Work Relative Value Units-per-Hour (wRVU/hr) and Dollars-per-Hour. METHODS The 2016–2021 Pediatric NSQIP database was queried for posterior spinal fusion cases (CPT 22800, 22802, 22804) for spinal deformity. Cases lacking operative time or wRVU data were excluded. ICD-10 codes were used to determine etiology. Total wRVUs (TwRVU) were calculated by combining primary and additional billed CPT codes. TwRVU-per-hour and Dollars-per-hour were derived using CMS conversion rates. Linear regression assessed operative time effects, and ANOVA compared etiologies. RESULTS A total of 31,739 patients were included (70.0% idiopathic, 18.0% neuromuscular, 0.6% syndromic, 4.5% congenital, 3.3% kyphosis, 3.6% other; mean age 13.8 ± 2.7 years; 68.2% female). Longer operative time was associated with decreased compensation, with each additional hour associated with a reduction of 2.38 TwRVUs ($79.87; p<0.001). In neuromuscular cases, each additional hour resulted in a $56.28 decrease, while in kyphosis cases the decrease was $144.91 per hour. Compensation rates also varied by etiology (p=0.002), with neuromuscular cases reimbursed at $429.13/hour and kyphosis cases at $554.42/hour. CONCLUSIONS Increased operative time and surgical etiology are associated with decreased compensation per hour. Current reimbursement models do not adequately reflect operative complexity or duration, highlighting disparities in financial compensation for spinal deformity surgery. FDA Device/Drug Status This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND:Surgical correction of neuromuscular scoliosis (NMS) carries a high risk of perioperative cardiopulmonary complications, including delayed extubation. This study aims to determine preoperative risk factors of delayed extubation after operative correction of neuromuscular scoliosis. METHODS:A retrospective chart review identified consecutive patients with NMS surgically treated at an urban academic institution. In accordance with institutional protocol, all patients received preoperative cardiac clearance, including echocardiography. Delayed extubation was defined as intubation for >1 day (24 h). Preoperative and intraoperative variables were compared between patients intubated for ≤24 hours and those intubated for >24 hours. Because several diagnoses were represented by small numbers, individual diagnoses were not included as separate variables; instead, univariate analyses were stratified by cerebral palsy (CP) and non-CP cohorts. Multivariate linear regression analyses were then performed to determine whether preoperative and intraoperative variables were associated with the number of days intubated (NDI). A receiver operating characteristic (ROC) curve was constructed to assess the ability of left ventricular ejection fraction (LVEF) to predict delayed extubation and identify the optimal cutoff. RESULTS:Forty-three patients met the inclusion criteria. In subgroup univariate analyses, greater blood loss and blood loss per level fused were associated with delayed extubation in both CP and non-CP cohorts. LVEF was negatively associated with the number of days intubated in the CP cohort on univariate analysis (r=-0.442, P=0.035), and the non-CP cohort showed a similar trend (r=-0.529, P=0.063). In the overall cohort, lower LVEF remained independently associated with prolonged intubation on multivariable analysis (β=-0.11, 95% CI: -0.18 to -0.04; P=0.003). In adjusted subgroup models, LVEF was not independently significant in either cohort. ROC analysis demonstrated an area under the curve of 0.78 for CP and 0.57 for non-CP. CONCLUSIONS:Lower LVEF appears to be associated with delayed extubation in the overall cohort, and subgroup univariate analyses suggest a similar association in the CP cohort. Preoperative echocardiography may help identify patients at risk for delayed extubation and allow for proper preoperative optimization, preparation, and counseling. LEVEL OF EVIDENCE:level III.

Background:Chordoma is a rare bone cancer arising from the embryonic notochord with special predilection to the axial skeleton. The locally destructive nature and metastatic potential of chordomas can lead to devastating outcomes in terms of survival. The purpose of this study was to examine potential risk factors predictive of metastatic disease at presentation and prognostic factors in patients with metastasis. Methods:SEER was used to classify each patient as having metastatic or localized disease at the time of diagnosis. Patient-specific and tumor characteristics were analyzed to determine which factors were predictive of an increased rate of metastatic disease at presentation. These factors were analyzed using univariate as well as a multivariate logistic regression model. Prognostic factors for survival were analyzed using the Kaplan-Meier estimates with log-rank tests, and Cox proportional hazards models. Results:We identified 1,241 cases of chordoma affecting the axial skeleton, and 117 (9.4%) of the patients presented with metastatic disease. The most common locations for metastasis at presentation were lung (6.0%), followed by bone (5.1%) and liver (3.4%). Based on the unadjusted logistic regression analysis, patients had the highest odds of metastatic disease at presentation if they had a tumor located in the sacrococcygeal area (OR = 1.72; 95% CI, 1.11-2.68; p = .015), a tumor with a dedifferentiated histological subtype (OR = 7.42; 95% CI, 2.31-23.79; p = .001) and a tumor size greater than 10 cm (OR = 4.57; 95% CI, 2.52-8.28; p = .009). Only the histological subtype remained significant when combined in a multivariate model controlling for age, sex, race, tumor location, histology, and size. For patients with recorded tumor size information (n = 858), the odds of metastasis at presentation increased by 12.2% with each additional centimeter of tumor size (OR = 1.122; 95% CI, 1.072-1.175; p < .0001). However, this lost significance in the multivariate model. Advanced age (hazard ratio, 2.06; 95% confidence interval, (1.18-3.60); p = .011) and dedifferentiated subtype (hazard ratio, 4.7; 95% confidence interval, (1.33-16.8); p = .02) were significant prognostic factors for survival in patients with metastatic chordoma. Conclusions:Chordoma patients with dedifferentiated histological subtype were more likely to have metastatic disease at presentation. Advanced age and dedifferentiated histological subtype were independent predictors of increased mortality in patients with metastatic chordoma. Identification of this high-risk group may help providers in counseling their patients regarding the likelihood of discovering metastatic disease at the time of diagnosis of chordoma and predicting long term prognosis.

BACKGROUND CONTEXT Adequate pain control after lumbar spinal surgery is essential for achieving optimal outcomes. While opioid analgesics have shown to be an effective tool in controlling pain, they come with the risk of patients becoming opioid dependent. Previous studies have demonstrated that administration of glucocorticoids after spinal surgery is associated with decreased postoperative pain scores. There is some hesitancy by surgeons to use glucocorticoids in lumbar fusion due to the risk of wound complications and pseudoarthrosis. To date, no large-scale studies have investigated the effects of postoperative methylprednisolone on opioid utilization following lumbar spinal fusions. PURPOSE The purpose of this study was to utilize a large, international database with a propensity-matched cohort to analyze the primary outcome of opioid utilization after lumbar fusion for patients who received postoperative methylprednisolone compared to those who did not. STUDY DESIGN/SETTING This was a large, retrospective international database analysis utilizing the TriNetX platform. PATIENT SAMPLE All patients in the TriNetX platform who underwent lumbar fusion with a minimum follow-up of 30 days were included for analysis. Patients were excluded if they had received methylprednisolone at any point in the year preceding the index surgery. OUTCOME MEASURES The primary outcome measure was opioid utilization at 7, 14, and 30 days postoperatively. Secondary outcome measures included bowel regimen use, postoperative ileus, deep venous thrombosis (DVT), pulmonary embolism (PE), surgical site infection, wound disruption, hospital readmission, and emergency department visits at the same time points. At 1- and 2-years postoperatively, additional outcomes included in our analysis were mechanical/hardware complications and pseudoarthrosis. METHODS Patients in the TriNetX platform who underwent lumbar fusion with a minimum follow-up of 30 days were identified. Patients were then split into two groups: those who received postoperative methylprednisolone and those who did not. These patients were then propensity-matched 1:1 based on sex, age, ethnicity, and additional comorbidities. Analysis was performed for the above outcome measures. RESULTS After propensity-matched analysis, 13,209 patients were included in each group. At all short-term time points of 7, 14, and 30 days, patients who received methylprednisolone had a 0.771 (HR 0.751 – 0.792, p < 0.001) times lower risk, 0.788 times lower risk (0.768 – 0.809, p < 0.001), and 0.792 (0.772 – 0.812, p < 0.001) times lower risk of opioid utilization, respectively. Similarly, at 7 (2.1 ± 1.9 versus 2.8 ± 2.0, p < 0.001), 14 (2.7 ± 2.8 versus 3.6 ± 3.2, p < 0.001), and 30 days (3.4 ± 4.2 versus 4.5 ± 4.7, p < 0.001) postoperatively, patients who received methylprednisolone had a significantly lower number of opioid prescriptions. Additionally, at all short-term time points, patients who received methylprednisolone had less bowel regimen utilization and prescriptions (p < 0.001). There was a decreased risk of DVT at 7 and 30 days, as well as a decreased risk of PE at 14 days for those who received methylprednisolone (p < 0.05). At all time points, there was no increased risk of surgical site infection or wound complications with methylprednisolone use. At both 1 year and 2 years postoperatively, patients who received methylprednisolone had a decreased risk of mechanical/hardware complications as well as pseudoarthrosis. CONCLUSIONS Postoperative methylprednisolone administration may provide a valuable adjunct in decreasing the utilization of opioids in the immediate postoperative period without increasing the risk of pseudoarthrosis, mechanical complications, surgical site infection or wound complications. Further randomized trials may help elucidate the utility of methylprednisolone for postoperative pain control. FDA Device/Drug Status This abstract does not discuss or include any applicable devices or drugs.

PurposeSince its release in November 2022, Chat Generative Pre-Trained Transformer 3.5 (ChatGPT), a complex machine learning model, has garnered more than 100 million users worldwide. The aim of this study is to determine how well ChatGPT can generate novel systematic review ideas on topics within spine surgery.MethodsChatGPT was instructed to give ten novel systematic review ideas for five popular topics in spine surgery literature: microdiscectomy, laminectomy, spinal fusion, kyphoplasty and disc replacement. A comprehensive literature search was conducted in PubMed, CINAHL, EMBASE and Cochrane. The number of nonsystematic review articles and number of systematic review papers that had been published on each ChatGPT-generated idea were recorded.ResultsOverall, ChatGPT had a 68% accuracy rate in creating novel systematic review ideas. More specifically, the accuracy rates were 80%, 80%, 40%, 70% and 70% for microdiscectomy, laminectomy, spinal fusion, kyphoplasty and disc replacement, respectively. However, there was a 32% rate of ChatGPT generating ideas for which there were 0 nonsystematic review articles published. There was a 71.4%, 50%, 22.2%, 50%, 62.5% and 51.2% success rate of generating novel systematic review ideas, for which there were also nonsystematic reviews published, for microdiscectomy, laminectomy, spinal fusion, kyphoplasty, disc replacement and overall, respectively.ConclusionsChatGPT generated novel systematic review ideas at an overall rate of 68%. ChatGPT can help identify knowledge gaps in spine research that warrant further investigation, when used under supervision of an experienced spine specialist. This technology can be erroneous and lacks intrinsic logic; so, it should never be used in isolation.Level of EvidenceNot applicable.

Background: The Internet is an important source of information for patients, but its effectiveness relies on the readability of its content. Patient education materials (PEMs) should be written at or below a sixthgrade reading level as outlined by agencies such as the American Medical Association. This study assessed PEMs' readability for the novel anterior vertebral body tethering (AVBT), distraction - based methods, and posterior spinal fusion (PSF) in treating pediatric spinal deformity. Methods: An online search identified PEMs using the terms "anterior vertebral body tethering," "growing rods scoliosis," and "posterior spinal fusion pediatric scoliosis." We selected the first 20 general medical websites (GMWs) and 10 academic health institution websites (AHIWs) discussing each treatment (90 websites total). Readability tests for each webpage were conducted using Readability Studio software. Reading grade levels (RGLs), which correspond to the US grade at which one is expected to comprehend the text, were calculated for sources and independent t tests compared with RGLs between treatment types. Results: The mean RGL was 12.1 +/- 2.0. No articles were below a sixthgrade reading level, with only 2.2% at the sixthgrade reading level. AVBT articles had a higher RGL than distraction - based methods (12.7 +/- 1.6 vs 11.9 +/- 1.9, P = 0.082) and PSF (12.7 +/- 1.6 vs 11.6 +/- 2.3, P = 0.032). Materials for distraction - based methods and PSF were comparable (11.9 +/- 1.9 vs 11.6 +/- 2.3, P = 0.566). Among GMWs, AVBT materials had a higher RGL than distraction - based methods (12.9 +/- 1.4 vs 12.1 +/- 1.8, P = 0.133) and PSF (12.9 +/- 1.4 vs 11.4 +/- 2.4, P = 0.016). Clinical Relevance: Patients' health literacy is important for shared decision- making. Assessing the readability of scoliosis treatment PEMs guides physicians when sharing resources and discussing treatment with patients. Conclusion: Both GMWs and AHIWs exceed recommended RGLs, which may limit patient and parent understanding. Within GMWs, AVBT materials are written at a higher RGL than other treatments, which may hinder informed decision- making and patient outcomes. Efforts should be made to create online resources at the appropriate RGL. At the very least, patients and parents may be directed toward AHIWs; RGLs are more consistent. Level of Evidence: 3.

Background: Approximately 50% of patients with congenital scoliosis will require surgical treatment to prevent further progression. Outcomes following congenital scoliosis are sparse in the literature. The purpose of this study was to identify independent risk factors associated with unplanned readmission and prolonged length of stay (LOS) in patients undergoing primary surgical treatment for congenital scoliosis. Methods: The National Surgical Quality Improvement Database- Pediatric was queried for database years 2016-2018 to identify patients with congenital scoliosis who underwent primary posterior fusion of the spine. Patient demographics, comorbidities, and operative variables, such as the number of levels fused and the American Society of Anesthesiologists (ASA) classificaiton, were collected. Univariate and multivariate analyses of patient factors were performed to test for association with readmission within 30 days and prolonged LOS (>4 days). Results: Eight hundred sixteen patients were identified. The average age was 11.3 +/- 4.02 years, and the mean postoperative LOS was 4.64 +/- 3.71 days. Forty- three patients (5.40%) were readmitted, and 73 patients (8.96%) had prolonged LOS. Independent risk factors associated with prolonged LOS included chronic lung disease (P P < 0.001), presence of a tracheostomy (P P < 0.001), structural central nervous system abnormality (P P = 0.039), oxygen support (P P < 0.001), and number of levels fused (P P = 0.008). The factors independently associated with unplanned readmission were fusion to the pelvis (P P = 0.004) and LOS >4 days (P P = 0.008). Conclusions: Prolonged LOS and readmission are widely being used as quality and performance metrics for hospitals. Congenital scoliosis, which often progresses rapidly resulting in significant deformity, frequently requires surgery at an earlier age than idiopathic and neuromuscular deformity. Nevertheless, 30- day outcomes for surgical intervention have not been thoroughly studied. The present study identifies risk factors for prolonged LOS and readmission, which can facilitate preoperative planning, patient/family counseling, and postoperative care.

Duchenne muscular dystrophy (DMD), a genetic condition marked by progressive muscle degeneration, presents notable orthopaedic challenges, especially scoliosis, which deteriorates patients' quality of life by affecting sitting balance and complicating cardiac and respiratory functions. Current orthopaedic management strategies emphasize early intervention with corticosteroids to delay disease progression and the use of surgical spinal fusion to address severe scoliosis, aiming to enhance sitting balance, alleviate discomfort, and potentially extend patient lifespan. Despite advancements, optimal management requires ongoing research to refine therapeutic approaches, ensuring improved outcomes for patients with DMD. This review synthesizes recent findings on surgical and nonsurgical interventions, underscoring the importance of a multidisciplinary approach tailored to the dynamic needs of patients with DMD.

Background: For patients with back pain from osteoporotic vertebral compression fractures (VCFs), vertebral augmentation remains the most utilized surgical intervention. Previous studies report 30 -day readmission and mortality rates of up to 10% and 2%, respectively. These studies, however, have included patients with pathologic fractures and combined patients in different admission settings. We undertook the current study to address such shortcomings, which make risk stratification and appropriate counseling difficult.Methods: Four consecutive years of the National Surgical Quality Improvement Program database were queried. Patients who underwent vertebral augmentation for osteoporotic VCFs were divided into 3 groups: (1) outpatient group (defined as patients with same -day discharge), (2) inpatient group (defined as those who were admitted postoperatively), and (3) preprocedure hospitalized group (defined as those who were already inpatient or were at acute/intermediate care facilities and transferred). Postoperative 30 -day complications and readmission rates were compared between different groups and examined using multivariate analyses.Results: A total of 1023 patients underwent outpatient surgery; 503 were admitted on the day of surgery; and 149 patients were already in-hospital or were transferred from other facility. Mortality rates were 0.68%, 0.60%, and 2.68%, and readmission rates were 6.26%, 6.76%, and 12.8%, for outpatient, inpatient, and preprocedure hospitalization cohorts, respectively. Multivariate analyses identified preprocedure hospitalization as an independent risk factor for urinary tract infection (UTI; OR = 3.98, 95% CI = 1.41-11.20, P = 0.028), pneumonia (OR = 19.69, 95% CI = 3.81-101.65, P < 0.001), readmission (OR = 1.86, 95% CI = 1.06-3.26, P = 0.032), and mortality (OR = 4.49, 95% CI = 1.22-16.53, P = 0.024).Conclusion: Our findings suggest that published rates of complications and mortality are substantially impacted by the cohort of patients who are already hospitalized or transferred from other facilities. Such patients are at a higher risk of UTI, pneumonia, readmission, and mortality. Conversely, we show that a relatively healthy patient being offered outpatient same -day augmentation has a readmission risk 40% lower and a mortality risk 3 times lower than previously reported.

Introduction Primary hip hemiarthroplasty (HHA) is frequently utilized to treat geriatric hip fractures, which are associated with significantly higher morbidity and mortality. While not particularly common, surgical site infection (SSI) is a major complication that frequently requires revision surgery in a frail population. The objective of this study was to determine the incidence of and risk factors for SSI after HHA in hip fracture patients. Materials and methods This retrospective cohort study was performed using the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) database. Geriatric patients (65+) who underwent HHA for non-pathologic, traumatic hip fractures between 2016–2017 were included. Demographic variables, comorbidities, operative variables, and complications were compared between "SSI" and "non-SSI" groups. Multivariate regression identified independent risk factors for postoperative SSI. Significance was set at P = 0.05. Results A total of 6169 patients were included. The overall incidence of SSI was 1.3%. SSI was significantly associated with body mass index (BMI), preoperative functional status, congestive heart failure, chronic corticosteroid use, intraoperative time, sepsis, wound dehiscence, readmission within 30-days, and reoperation. On multivariate analysis, chronic steroid use (OR: 2.30, 95% CI: 1.13–4.70), BMI ≥ 35 kg/m 2 (OR: 3.59, 95% CI: 1.57–8.18), and intraoperative time ≥120 mins (OR: 2.15, 95% CI: 1.08–4.27) were found to be independent risk factors. Conclusions Postoperative SSI is a serious complication that is responsible for prolonged hospital stays, increased mortality, and greater healthcare costs. Here, we identified multiple risk factors for SSI after primary HHA in the US elderly population.

Context: Delayed, postoperative, spine infections are rare, most commonly occurring secondary to fastidious, less virulent pathogens. The etiology may involve a distant infectious focus, not related to the index operation. Patients may present months, or even years postoperatively with pain related to mechanical implant failure, often without additional signs of systemic infection.Findings: We present the case of a 59-year-old male who developed rapid disk degeneration and implant failure seven months following instrumented lumbar fusion surgery. The causal organism was found to be Micromonas micros, an anaerobic bacterium typically located in the oral cavity and associated with periodontal disease. The patient was found to have extensive oral caries, which were presumed to have occurred secondary to poor oral hygiene and his use of fentanyl lozenges for chronic back pain. The patient was treated with revision staged spinal surgery and long-term intravenous antibiotics.Conclusion/clinical relevance: This case highlights an unusual etiology of delayed postoperative spinal implant failure and provides evidence for periodontal disease as a source of hematogenous seeding in postoperative spinal infections. The orthopaedist should also be aware of the potential relationship between poor oral hygiene and the use of high sugar content fentanyl lozenges in treating chronic back pain in these patients.

To assess the efficacy and safety of intrawound antibiotics in posterior fusions for adolescent idiopathic scoliosis (AIS). The NSQIP-Pediatric databases 2016–2018 were utilized. Patients 10 years of age or older with AIS who underwent posterior fusion were selected and divided into two cohorts based on the receipt of intrawound antibiotics. Patient characteristics and complications were compared. Multivariate analyses were performed to determine the efficacy and safety of intrawound antibiotics. A total of 4203 patients received intrawound antibiotics while 879 patients did not. The intrawound antibiotic group had longer constructs, higher blood loss, and longer operative times, factors historically associated with higher infection rates. Those that received intrawound antibiotics had SSI rate of 0.69

BACKGROUND CONTEXT Chordoma is a rare bone cancer arising from the embryonic notochord with special predilection to the axial skeleton. The locally destructive nature and metastatic potential of chordomas can lead to devastating outcomes in terms of survival. PURPOSE The purpose of this study was to examine potential risk factors predictive of metastatic disease at presentation and prognostic factors in patients with metastasis. STUDY DESIGN/SETTING Database study utilizing the Surveillance, Epidemiology, and End Results (SEER) Program database. PATIENT SAMPLE Patients diagnosed with chordoma from 2000 to 2018 queried from the SEER database. OUTCOME MEASURES The outcome of interest was the presence of metastatic disease at the time of presentation with chordoma and prognostic factors in patients with metastatic chordoma. METHODS The Surveillance, Epidemiology, and End Results (SEER) Program database was used to identify all patients diagnosed with chordoma from 2000 to 2018 and to classify each patient as having metastatic or localized disease at the time of diagnosis. Patient-specific and tumor characteristics were analyzed to determine which factors were predictive of an increased rate of metastatic disease at presentation. These factors were analyzed using univariate as well as a multivariate logistic regression model. Prognostic factors were analyzed using the Kaplan-Meier estimates with log-rank tests, and Cox proportional hazards models. RESULTS We identified 1,241 cases of chordoma affecting the axial skeleton, and 117 (9.4%) of the patients presented with metastatic disease. The most common locations for metastasis at presentation were lung (6.0%), followed by bone (5.1%) and liver (3.4%). Based on the unadjusted logistic regression analysis, patients had the highest odds of metastatic disease at presentation if they had a tumor located in the sacrococcygeal area (OR = 1.72; 95% CI, 1.11 to 2.68; p=0.015), a tumor with a dedifferentiated histological subtype (OR = 7.42; 95% CI, 2.31 to 23.79; p=0.001) and a tumor size greater than 10 cm (OR = 4.57; 95% CI, 2.52 to 8.28; p=0.009). Only the histological subtype remained significant when combined in a multivariate model controlling for age, sex, race, tumor location, histology and size. For patients with recorded tumor size information (n = 858), the odds of metastasis at presentation increased by 12.2% with each additional centimeter of tumor size (OR = 1.122; 95% CI, 1.072 to 1.175; p <0.0001). However, this lost significance in the multivariate model. Advanced age (hazard ratio, 2.06; 95% confidence interval, 1.18 to 3.60; p = 0.011) and dedifferentiated subtype (hazard ratio, 4.7; 95% confidence interval, 1.33 to 16.8; p = 0.02) were significant negative prognostic factors for survival in patients with metastatic chordoma. CONCLUSIONS Chordoma patients with dedifferentiated histological subtype were more likely to have metastatic disease at presentation. Advanced age and dedifferentiated histological subtype were independent predictors of increased mortality in patients with metastatic chordoma. Identification of this high-risk group may help providers in counseling their patients regarding the likelihood of discovering metastatic disease at the time of diagnosis of chordoma and predicting long-term prognosis. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

The purpose of this study was to determine if locally applied insulin has a dose-responsive effect on posterolateral lumbar fusion. Adult male New Zealand White rabbits underwent posterolateral intertransverse spinal fusions (PLFs) at L5-L6 using suboptimal amounts of autograft. Fusion sites were treated with collagen sponge soaked in saline (control, n = 11), or with insulin at low (5 or 10 units, n = 13), mid (20 units, n = 11), and high (40 units, n = 11) doses. Rabbits were euthanized at 6 weeks. The L5-L6 spine segment underwent manual palpation and radiographic evaluation performed by two fellowship trained spine surgeons blinded to treatment. Differences between groups were evaluated by analysis of variance on ranks followed by post-hoc Dunn's tests. Forty-three rabbits were euthanized at the planned 6 weeks endpoint, while three died or were euthanized prior to the endpoint. Radiographic evaluation found bilateral solid fusion in 10%, 31%, 60%, and 60% of the rabbits from the control and low, mid, and high-dose insulin-treated groups, respectively (p < 0.05). As per manual palpation, 7 of 10 rabbits in the mid-dose insulin group were fused as compared to 1 of 10 rabbits in the control group (p < 0.05). This study demonstrates that insulin enhanced the effectiveness of autograft to increase fusion success in the rabbit PLF model. The study indicates that insulin or insulin-mimetic compounds can be used to promote bone regeneration.

Bone allograft is widely used to treat large bone defects or complex fractures. However, processing methods can significantly compromise allograft osteogenic activity. Adjuvants that can restore the osteogenic activity of processed allograft should improve clinical outcomes. In this study, zinc was tested as an adjuvant to increase the osteogenic activity of human allograft in a Rag2 null rat femoral defect model. Femoral defects were treated with human demineralized bone matrix (DBM) mixed with carboxy methyl cellulose containing ZnCl2 (0, 75, 150, 300 µg) or Zn stearate (347 µg). Rat femur defects treated with DBM-ZnCl2 (75 µg) and DBM-Zn stearate (347 µg) showed increased calcified tissue in the defect site compared to DBM alone. Radiograph scoring and µCT (microcomputed tomography) analysis showed an increased amount of bone formation at the defects treated with DBM-Zn stearate. Use of zinc as an adjuvant was also tested using human cancellous bone chips. The bone chips were soaked in ZnCl2 solutions before being added to defect sites. Zn adsorbed onto the chips in a time- and concentration-dependent manner. Rat femur defects treated with Zn-bound bone chips had more new bone in the defects based on µCT and histomorphometric analyses. The results indicate that zinc supplementation of human bone allograft improves allograft osteogenic activity in the rat femur defect model.

BACKGROUND CONTEXT Spinal fusion surgeries increased by 137% between the years 1998–2008 and the requirement will continue to grow as the implications for fusion expand. Furthermore, total hospital charges, excluding charges for readmission, for 3.6 million spinal fusion surgeries, performed between 2001-2010 in United States, were more than $287 billion. Many such cases involved the use of pedicle screw fixation. Screw placement accuracy impacts fusion rate, adjacent level disease, and risk for neurovascular complications. Reported rates for screw misplacement, which required reoperation, were ranging up to 42%. Image guided surgical systems have provided means to improve screw placement accuracy, however, the clinical accuracy requirements for certain levels of spine still exceed the accuracy of current image guided surgical systems. Furthermore, most of these systems are based on the use of intra-operative two-dimensional (2D)/three-dimensional (3D) fluoroscopy imaging which operate with ionizing radiation. Finally, most of the available commercial systems are expensive resulting in a significant capital expense to the hospital, have a steep learning curve, and require new workflow to be established. PURPOSE The purpose of this work is to demonstrate that with improved modeling, segmentation and registration tools real-time 3D ultrasound can be used for spinal imaging and has potential to be used in spinal fusion surgeries. Our long-term goal is the successful integration of 3D ultrasound (US) as a standard of care intra-operative imaging modality for spinal fusion surgeries which has not been achieved so far. STUDY DESIGN/SETTING The computational methods developed during the project period were evaluated on in vivo ultrasound scans collected from healthy individuals. Data collection involved the use of a clinical grade ultrasound machine as well as a point of care wireless ultrasound device. Evaluations were performed against gold standard expert annotations. PATIENT SAMPLE A total of 27 healthy subjects were enrolled during the study. We have also collected retrospective spine CT scans in order to built a statistical spine shape model. OUTCOME MEASURES Evaluation studies were performed by measuring surface localization accuracy, classification accuracy and target registration accuracy. METHODS We have designed new artificial intelligence methods for segmentation, enhancement and classification of spine surfaces from ultrasound data. In order to provide a solution for manual operation of the ultrasound transducer during data collection, we have developed methods, based on deep learning, for automatic guidance of the ultrasound transducer to the correct scan plane. Finally, we have developed a novel machine learning-based point cloud registration method which does not require initialization to start the registration. RESULTS Our proposed methods outperform current state of the art in accuracy, robustness and processing time. For anatomical landmark localization we have obtained 0.1 mm (Standard deviation 0.2 mm) accuracy with a processing time of 54 milliseconds. We achieve submillimeter anatomical landmark localization accuracy. Sensitivity and specificity values for scan plane and vertebrae level classification were greater than 86%. CONCLUSIONS Our specific contribution in this work include: 1) a robust, accurate and fast spine bone enhancement and segmentation method from ultrasound data; 2) a multi-modal intra-operative image fusion strategy which can be applied to different orthopedic procedures as well. Future work will involve validation of our proposed methods on cadaver studies for pedicle screw guidance. The proposed ultrasound-based navigation system can also be used in conjunction with any existing 2D fluoroscopy/CT-nav-based navigation in order to provide additional augmentation and improve the overall accuracy of these systems while reducing the radiation exposure. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

In ultrasound (US)-based computer-assisted orthopedic surgery (CAOS), accurate and robust intra-operative registration in real-time is vital in securing the reliable outcomes for surgical image guidance. For this purpose, we focus on developing a hierarchical registration method, using reinforcement learning (RL), for 3-D registration of pre-operative computed tomography (CT) data to intra-operative US. In the RL-based registration procedure, we proposed a supervised Q-learning framework for learning the sequence of motion action to achieve the optimal alignment. Within the approach, the agent was modeled using PointNet++ with the mis-aligned point set from US and CT as the input, and the next optimal action as the output. Evaluation studies achieved average target registration error (TRE) of 3.82 mm with success rate of 92.7% and an average time of 8.36 seconds. We achieve 57.1% improvement in success rate over state of the art.

To provide a safe alternative, for intra-operative fluoroscopy, ultrasound (US) has been investigated as an alternative safe imaging modality for various computer assisted orthopedic surgery (CAOS) procedures. However, low signal to noise ratio, imaging artifacts and bone surfaces appearing several millimeters (mm) in thickness have hindered the wide spread application of US in CAOS. In order to provide a solution for these problems, research has focused on the development of accurate, robust and real-time bone segmentation methods. Most recently methods based on deep learning have shown very promising results. However, scarcity of bone US data introduces significant challenges when training deep learning models. In this work, we propose a computational method, based on a novel generative adversarial network (GAN) architecture, to (1) produce synthetic B-mode US images and (2) their corresponding segmented bone surface masks in real-time. We show how a duality concept can be implemented for such tasks. Armed by two convolutional blocks, referred to as self-projection and self-attention blocks, our proposed GAN model synthesizes realistic B-mode bone US image and segmented bone masks. Quantitative and qualitative evaluation studies are performed on 1235 scans collected from 27 subjects using two different US machines to show comparison results of our model against state-of-the-art GANs for the task of bone surface segmentation using U-net.

Study Design: This was a retrospective cohort study. Objective: The objective of this study was to analyze readmission rates among patients undergoing anterior cervical discectomy and fusion (ACDF), determine which factors were associated with higher readmission rates, and develop a scale for utilization during surgical planning. Summary of Background Data: ACDF is the most common surgical treatment for many cervical disk pathologies. With the Centers for Medicare and Medicaid Services selecting readmissions as a measure of health care quality, there has been an increased focus on reducing readmissions. Materials and Methods: There were 114,174 recorded ACDF surgeries in the derivation cohort, the State Inpatient Database (SID) of New York and California between 2006 and 2014. There were 115,829 ACDF surgeries recorded in the validation cohort, the SID from Florida and Washington over the same time period. After identification of risk factors using univariate and multivariate analysis of the derivation cohort, a predictive scale was generated and tested utilizing the validation cohort. Results: Overall, readmission rates within 30 days of discharge were 5.87% and 5.52% in the derivation and validation cohorts, respectively. On multivariate analysis of the derivation cohort, age older than 80 years [odds ratio (OR), 1.67] male sex (OR, 1.16), Medicaid insurance (OR, 1.90), Medicare insurance (OR, 1.64), revision ACDF (OR, 1.43), anemia (OR, 1.45), chronic lung disease (OR, 1.23), coagulopathy (OR, 1.42), congestive heart failure (OR, 1.31), diabetes (OR, 1.23), fluid and electrolyte disorder (OR, 1.56), liver disease (OR, 1.37), renal failure (OR, 1.59), and myelopathy (OR, 1.19) were found to be statistically significant predictors for readmission. These factors were incorporated into a numeric scale that, that when tested on the validation cohort, could explain 97.1% of the variability in readmission rate. Conclusions: Overall, 30-day readmission following ACDF surgery was 5%–6%. A novel risk scale based on factors associated with increased readmission rates may be helpful in identifying patients who require additional optimization to reduce perioperative morbidity. Level of Evidence: Level III—prognostic.

BACKGROUND CONTEXT For elderly patients with unremitting back pain secondary to osteoporotic vertebral compression fractures (VCF), vertebral augmentation remains the most utilized surgical intervention. Previous studies have examined perioperative complications, with 30-day readmission and mortality rates of up to 10% and 2%, respectively. Most such studies have included patients with pathologic fractures and those that had been inpatients prior to their procedures. Such shortcomings make it difficult for surgeons in office settings to accurately counsel patients regarding their risks for electively scheduled augmentation. PURPOSE To determine the 30-day postoperative complication rates for inpatient versus outpatient elective vertebral augmentation procedure performed for osteoporotic VCFs. STUDY DESIGN/SETTING Retrospective analysis of prospectively collected database. PATIENT SAMPLE Patients that underwent kyphoplasty or vertebroplasty were identified using CPT codes. To identify elective cases, only patients designated with “elective” status and those with ASA score 3 or under were selected. Patients that were inpatient status prior to the procedure, patients that were transferred from outside facility, patients that required preoperative blood transfusion, and those who were dependent on ventilator were excluded. To select only the osteoporotic VCFs, patients with disseminated cancer and those that underwent chemotherapy or radiotherapy were excluded. OUTCOME MEASURES Outcomes investigated were mortality, sepsis, cardiovascular complications, re-intubation, pneumonia, renal complications, stroke, wound complications, UTI, DVT, PE and transfusion. Also assessed were unplanned reoperation, unplanned readmission and discharge destination. METHODS The NSQIP database 2011-2014 was queried. Rates of 30-day postoperative complications, reoperations and readmissions were compared between the inpatient and the outpatient groups using univariate analyses. Multivariable analysis was proposed, however, was not performed since univariate analyses did not reveal meaningful differences. RESULTS A total of 1,539 patients were identified. Of those, 555 patients underwent inpatient surgery while 984 patients underwent outpatient surgery. Mean ages for inpatient and outpatient groups were 76.0 and 73.7, respectively. The 30-day postoperative complication rates were low for both groups. The mortality rates for the inpatient and outpatient groups were 0.19% and 0.31%, respectively, with no significant difference. UTI and sepsis were the only complications significantly different between the two groups. UTI occurred in 2.28% in the inpatient group and 0.94% in the outpatient group. Sepsis occurred in 0.95% of patients that underwent inpatient surgery, while no patient that underwent outpatient procedure sustained sepsis. Readmission (7.98% vs 5.74%) and reoperation (3.23% vs 2.92%) were both higher in inpatient group, however, the differences were not significant. CONCLUSIONS The only statistically significant differences in short-term morbidity from elective vertebral augmentation performed for osteoporotic VCFs were sepsis and UTI, with higher rates in inpatient group. The analysis suggests that outpatient vertebral augmentation may be safely performed in appropriate patient cohort. Compared with published studies that included pathologic fractures and patients that had been previously admitted, our study reported substantially lower 30-day mortality and readmission rates for electively scheduled augmentation of osteoporotic VCFs. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. For elderly patients with unremitting back pain secondary to osteoporotic vertebral compression fractures (VCF), vertebral augmentation remains the most utilized surgical intervention. Previous studies have examined perioperative complications, with 30-day readmission and mortality rates of up to 10% and 2%, respectively. Most such studies have included patients with pathologic fractures and those that had been inpatients prior to their procedures. Such shortcomings make it difficult for surgeons in office settings to accurately counsel patients regarding their risks for electively scheduled augmentation. To determine the 30-day postoperative complication rates for inpatient versus outpatient elective vertebral augmentation procedure performed for osteoporotic VCFs. Retrospective analysis of prospectively collected database. Patients that underwent kyphoplasty or vertebroplasty were identified using CPT codes. To identify elective cases, only patients designated with “elective” status and those with ASA score 3 or under were selected. Patients that were inpatient status prior to the procedure, patients that were transferred from outside facility, patients that required preoperative blood transfusion, and those who were dependent on ventilator were excluded. To select only the osteoporotic VCFs, patients with disseminated cancer and those that underwent chemotherapy or radiotherapy were excluded. Outcomes investigated were mortality, sepsis, cardiovascular complications, re-intubation, pneumonia, renal complications, stroke, wound complications, UTI, DVT, PE and transfusion. Also assessed were unplanned reoperation, unplanned readmission and discharge destination. The NSQIP database 2011-2014 was queried. Rates of 30-day postoperative complications, reoperations and readmissions were compared between the inpatient and the outpatient groups using univariate analyses. Multivariable analysis was proposed, however, was not performed since univariate analyses did not reveal meaningful differences. A total of 1,539 patients were identified. Of those, 555 patients underwent inpatient surgery while 984 patients underwent outpatient surgery. Mean ages for inpatient and outpatient groups were 76.0 and 73.7, respectively. The 30-day postoperative complication rates were low for both groups. The mortality rates for the inpatient and outpatient groups were 0.19% and 0.31%, respectively, with no significant difference. UTI and sepsis were the only complications significantly different between the two groups. UTI occurred in 2.28% in the inpatient group and 0.94% in the outpatient group. Sepsis occurred in 0.95% of patients that underwent inpatient surgery, while no patient that underwent outpatient procedure sustained sepsis. Readmission (7.98% vs 5.74%) and reoperation (3.23% vs 2.92%) were both higher in inpatient group, however, the differences were not significant. The only statistically significant differences in short-term morbidity from elective vertebral augmentation performed for osteoporotic VCFs were sepsis and UTI, with higher rates in inpatient group. The analysis suggests that outpatient vertebral augmentation may be safely performed in appropriate patient cohort. Compared with published studies that included pathologic fractures and patients that had been previously admitted, our study reported substantially lower 30-day mortality and readmission rates for electively scheduled augmentation of osteoporotic VCFs.