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Background Context: Previous studies have found that insulin or insulin-like growth factor treatment can stimulate fracture healing in diabetic and normal animal models, and increase fusion rates in a rat spinal fusion model. Insulin-mimetic agents, such as zinc, have demonstrated antidiabetic effects in animal and human studies, and these agents that mimic the effects of insulin could produce the same beneficial effects on bone regeneration and spinal fusion.Purpose: The purpose of this study was to analyze the effects of locally applied zinc on spinal fusion in a rat model.Study Design/setting: Institutional Animal Care and Use Committee-approved animal study using Sprague-Dawley rats was used as the study design.Methods: Thirty Sprague-Dawley rats (450-500 g) underwent L4-L5 posterolateral lumbar fusion (PLF). After decortication and application of approximately 0.3 g of autograft per side, one of three pellets were added to each site: high-dose zinc calcium sulfate (ZnCaSO4), low-dose ZnCaSO4 (half of the high dose), or a control palmitic acid pellet (no Zn dose). Systemic blood glucose levels were measured 24 hours postoperatively. Rats were sacrificed after 8weeks and the PLFs analyzed qualitatively by manual palpation and radiograph review, and quantitatively by micro-computed tomography (CT) analysis of bone volume and trabecular thickness. Statistical analyses with p-values set at .05 were accomplished with analysis of variance, followed by posthoc tests for quantitative data, or Mann-Whitney rank tests for qualitative assessments.Results: Compared with controls, the low-dose zinc group demonstrated a significantly higher manual palpation grade (p=.011), radiographic score (p=.045), and bone formation on micro-CT (172.9 mm(3) vs. 126.7 mm(3) for controls) (p<.01). The high-dose zinc also demonstrated a significantly higher radiographic score (p=.017) and bone formation on micro-CT (172.7 mm(3) vs. 126.7 mm(3)) (p<.01) versus controls, and was trending toward higher manual palpation scores (p=.058).Conclusions: This study demonstrates the potential benefit of a locally applied insulin-mimetic agent, such as zinc, in a rat lumbar fusion model. Previous studies have demonstrated the benefits of local insulin application in the same model, and it appears that zinc has similar effects. [ABSTRACT FROM AUTHOR]

Commentary On: Yagi M, Hosogane N, Watanabe K, Asazuma T, Matsumoto M, Keio Spine Research Group. The paravertebral muscle and psoas for the maintenance of global spinal alignment in patient with degenerative lumbar scoliosis. Spine J 2016:16:451-8 (in this issue). [ABSTRACT FROM AUTHOR]

Background Context: Injuries at the cervicothoracic junction are common in patients with ankylosing spondylitis. These injuries present challenges for both initial and follow-up imagings. Purpose: To describe a case of a patient with ankylosing spondylitis who was treated with laminectomy and a cervicothoracic orthosis for a spinal epidural hematoma after a nondisplaced fracture at the cervicothoracic junction and to discuss the merits of stand-up magnetic resonance imaging (MRI) for follow-up evaluation of this type of injury. Study Design/setting: Case report. Methods: Clinical data of a patient with ankylosing spondylitis who sustained a nondisplaced C7 fracture are presented, followed by a detailed review of the literature concerning imaging techniques available for the evaluation of cervical spine trauma in this patient population. Results: The patient was treated with emergent laminectomy and evacuation of the epidural hematoma, followed by definitive management in a cervicothoracic orthosis secondary to medical comorbidities. The patient was then successfully followed postoperatively with stand-up MRI because conventional imaging techniques could not adequately image the injury level in an upright position. Conclusions: Cervicothoracic injuries are common in patients with ankylosing spondylitis and may be difficult to follow with conventional imaging techniques. Stand-up MRI is a relatively new modality that may offer significant advantages over conventional imaging because of the ability to evaluate the cervicothoracic junction in a more functional position and the lack of a confining space such as that found in standard MRI units. [ABSTRACT FROM AUTHOR]

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. Database study utilizing the Surveillance, Epidemiology, and End Results (SEER) Program database. Patients diagnosed with chordoma from 2000 to 2018 queried from the SEER database. 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. 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. 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. 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. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Abstract: Background context: The rates of pseudoarthrosis after a single-level spinal fusion have been reported up to 35%, and the agents that increase the rate of fusion have an important role in decreasing pseudoarthrosis after spinal fusion. Previous studies have analyzed the effects of local insulin application to an autograft in a rat segmental defect model. Defects treated with a time-released insulin implant had significantly more new bone formation and greater quality of bone compared with controls based on histology and histomorphometry. A time-released insulin implant may have similar effects when applied in a lumbar spinal fusion model. Purpose: This study analyzes the effects of a local time-released insulin implant applied to the fusion bed in a rat posterolateral lumbar spinal fusion model. Our hypothesis was twofold: first, a time-released insulin implant applied to the autograft bed in a rat posterolateral lumbar fusion will increase the rate of successful fusion and second, will alter the local environment of the fusion site by increasing the levels of local growth factors. Study design: Animal model (Institutional Animal Care and Use Committee approved) using 40 adult male Sprague-Dawley rats. Methods: Forty skeletally mature Sprague-Dawley rats weighing approximately 500 g each underwent posterolateral intertransverse lumbar fusions with iliac crest autograft from L4 to L5 using a Wiltse-type approach. After exposure of the transverse processes and high-speed burr decortication, a Linplant (Linshin Canada, Inc., ON, Canada) consisting of 95% microrecrystalized palmitic acid and 5% bovine insulin (experimental group) or a sham implant consisting of only palmitic acid (control group) was implanted on the fusion bed with iliac crest autograft. As per the manufacturer, the Linplant has a release rate of 2 U/day for a minimum of 40 days. The transverse processes and autograft beds of 10 animals from the experimental and 10 from the control group were harvested at Day 4 and analyzed for growth factors. The remaining 20 spines were harvested at 8 weeks and underwent a radiographic examination, manual palpation, and microcomputed tomographic (micro-CT) examination. Results: One of the 8-week control animals died on postoperative Day 1, likely due to anesthesia. In the groups sacrificed at Day 4, there was a significant increase in insulinlike growth factor-I (IGF-I) in the insulin treatment group compared with the controls (0.185 vs. 0.129; p=.001). No significant differences were demonstrated in the levels of transforming growth factor beta-1, platelet-derived growth factor-AB, and vascular endothelial growth factor between the groups (p=.461, .452, and .767 respectively). Based on the radiographs, 1 of 9 controls had a solid bilateral fusion mass, 2 of 9 had unilateral fusion mass, 3 of 9 had small fusion mass bilaterally, and 3 of 9 had graft resorption. The treatment group had solid bilateral fusion mass in 6 of 10 and unilateral fusion mass in 4 of 10, whereas a small bilateral fusion mass and graft resorption were not observed. The difference between the groups was significant (p=.0067). Based on manual palpation, only 1 of 9 controls was considered fused, 4 of 9 were partially fused, and 4 of 9 were not fused. In the treatment group, there were 6 of 10 fusions, 3 of 10 partial fusions, and 1 of 10 were not fused. The difference between the groups was significant (p=.0084). Based on the micro-CT, the mean bone volume of the control group was 126.7 mm3 and 203.8 mm3 in the insulin treatment group. The difference between the groups was significant (p=.0007). Conclusions: This study demonstrates the potential role of a time-released insulin implant as a bone graft enhancer using a rat posterolateral intertransverse lumbar fusion model. The insulin-treatment group had significantly higher fusion rates based on the radiographs and manual palpation and had significantly higher levels of IGF-I and significantly more bone volume on micro-CT. [Copyright &y& Elsevier]

Anterior cervical discectomy and fusion (ACDF) is the most common surgical treatment for a variety of cervical disk pathologies. With the Center for Medicare and Medicaid Services (CMS) selecting readmissions as a key measure of health care quality, increasing focus has been generated on the topic of reducing readmissions. The objective of this study was to analyze readmission rates in patients across several large state databases, analyze which factors were associated with risk of readmission, and develop a numeric scale for clinicians to utilize for prediction of readmission risk. Retrospective cohort study. A total of 91,550 ACDF surgeries were recorded in the State Inpatient Database (SID) of NY and CA between 2006 and 2014, which made up the derivation cohort to identify risk factors. There were 87,655 ACDF surgeries recorded in the SID from FL and WA over the same time period, making up the validation cohort. Readmission status within 30 days and goodness-of-fit of regression curve after application of scale to the validation cohort. Risk factors for readmission were identified using univariate and multivariate regression analysis of the derivation cohort. After identification of risk factors, odds ratios were then used to generate a predictive scale that was tested utilizing the validation cohort. An exponential regression model was applied to determine the goodness-of-fit of the scale to the readmission risk in the validation cohort. Overall readmission rates within 30 days of discharge were 5.68% and 5.29% in the derivation and validation cohorts, respectively. In both cohorts, patients with renal failure and congestive heart failure were readmitted most often. On multivariate analysis of the derivation cohort, age greater than 80 years (OR, 1.74) male gender (OR, 1.16), Medicaid Insurance (OR, 1.99), Medicare Insurance (OR, 1.72), self-pay insurance (OR, 1.42), anemia (OR, 1.45), chronic lung disease (OR, 1.23), coagulopathy (OR, 1.42), depression (OR, 1.15), diabetes (OR, 1.24), fluid and electrolyte disorder (OR, 1.63), hypertension (OR, 1.09), liver disease (OR, 1.34), and renal failure (OR, 1.79) were found to be statistically significant predictors for readmission. These factors were incorporated into a numeric risk scale that, when tested on the validation cohort, could explain 95.5% of the variability in readmission rate. Overall 30-day readmission following ACDF surgery was 5-6%. Factors including advanced age, male gender, Medicaid insurance, Medicare insurance, anemia, lung disease, congestive heart failure, coagulopathy, depression, diabetes, electrolyte disorder, hypertension, liver disease, and renal failure were found to be significant risk factors for 30-day readmission following ACDF surgery. A novel risk scale based on these factors may be helpful in identifying patients who require additional optimization to reduce perioperative morbidity. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Background context Traumatic bilateral-atlantoaxial dislocations are rare injuries. Hangman fractures, conversely, represent 4% to 7% of all cervical fractures and frequently involve a combination C1–C2 fracture pattern. Presently, there is no report in the English literature of a traumatic C2-spondylolisthesis associated with a C1–C2 rotatory dislocation. This injury complex cannot be cataloged using current classification schemes and no established treatment recommendations exist. Purpose To report a unique case of a Hangman fracture associated with bilateral C1–C2 rotatory-dislocation, which does not fit into existing classification systems, and discuss our treatment approach. Study design A clinical case report and review of the literature. Methods Chart review and analysis of relevant literature. There were no study-specific conflicts of interest. Results A 26-year-old man sustained a traumatic C2-spondylolisthesis along with C1–C2 rotatory subluxation in an automobile collision. The patient was originally placed in a halo crown and vest and then taken for an open reduction and stabilization through a posterior approach for persistent C1–C2 subluxation. The patient is currently 16 months postoperative and back to work as a plumber. Conclusions The injury complex encountered cannot be described using the available classification systems. Our treatment included initial stabilization with halo placement, followed by a posterior C1, C2, and C3 segmental reduction and fixation resulting in radiographic fusion and a good clinical outcome. [ABSTRACT FROM AUTHOR]