Bone marrow aspirate and bone marrow aspirate concentrate: Does the literature support use in long-bone nonunion and provide new insights into mechanism of action?

PURPOSE: To assess the use of bone marrow aspirate (BM) and bone marrow aspirate concentrate (BMAC) in the treatment of long-bone nonunion and to understand mechanism of action. METHODS: A systematic review of PubMed and EBSCOHost was completed to identify studies that investigated the use of BM or BMAC for the diagnosis of delayed union and/or nonunion of long-bone fractures. Studies of isolated bone marrow-mesenchymal stem cells (BM-MSCs) and use in non-long-bone fractures were excluded. Statistical analysis was confounded by heterogeneous fracture fixation methods, treatment history, and scaffold use. RESULTS: Our initial search yielded 430 publications, which was screened down to 25 studies. Successful treatment in aseptic nonunion was reported at 79-100% (BM) and 50-100% (BMAC). Septic nonunion rates were slightly better at 73-100% (BM) and 83.3-100% (BMAC). 18/24 studies report union rates > 80%. One study reports successful treatment of septic nonunion with BMAC and no antibiotics. A separate study reported a significant reduction in autograft reinfection rate when combined with BMAC (P = 0.009). Major adverse events include two deep infections at injection site and one case of heterotopic ossification. Most studies note transient mild donor site discomfort and potential injection site discomfort attributed to needle size. CONCLUSION: The current literature pertaining to use of BM/BMAC for nonunion is extremely heterogeneous in terms of patient population and concomitant treatment modalities. While results are promising for use of BM/BMAC with other gold standard treatment methodologies, the literature requires additional Level I data to clarify the impact of role BM/BMAC in treating nonunion when used alone and in combination with other modalities. LEVEL OF EVIDENCE: Level III.

Smoking Is Independently Associated with Increased Pain Severity and Interference in Patients with Traumatic Spinal Cord Injury.

Previous studies have shown a relationship between cigarette use and pain but never in the setting of traumatic spinal cord injury (TSCI). Therefore, the objectives of this study were to (1) determine whether smokers with TSCI experience increased pain compared with nonsmokers with TSCI and (2) determine whether smokers with TSCI experience worse functional outcomes than nonsmokers with TSCI. A retrospective analysis of the National Spinal Cord Injury Statistical Center database was performed. Pain severity, interference, and functional outcomes were compared between 514 nonsmokers and 124 smokers with American Spinal Injury Association (ASIA) C/D TSCI. Smokers reported higher scores for pain severity and interference compared with nonsmokers. These findings were significant on multivariable analysis. Smokers also reported higher rates of job loss compared with nonsmokers, but this finding was not significant on multivariable analysis. Smoking may be an independent risk factor for increased pain severity and interference in the setting of TSCI. (Journal of Surgical Orthopaedic Advances 33(2):103-107, 2024).

What Are the Differences in Hospital Cost Associated With the Use of Cemented Versus Cementless Femoral Stems in Hemiarthroplasty and Total Hip Arthroplasty for the Treatment of Femoral Neck Fracture?

BACKGROUND: The purpose of this study was to determine if there is a difference in hospital costs associated with the use of cemented versus cementless femoral stems in hemiarthroplasty (HA) and total hip arthroplasty (THA) for the treatment of femoral neck fracture (FNF). METHODS: This retrospective cohort study utilizes the 2019 Medicare Provider Analysis and Review Limited Data Set. Patients undergoing arthroplasty for the treatment of FNF were identified. Patients were grouped by cemented or cementless femoral stem fixation. There were 16,148 patients who underwent arthroplasty for FNF available: 4,913 THAs (3,705 patients who had cementless femoral stems and 1,208 patients who had cemented femoral stems) and 11,235 HAs (6,099 patients who had cementless femoral stems and 5,136 who had cemented femoral stems). Index hospital costs were estimated by multiplying total charges by cost-to-charge ratios. Costs were analyzed using univariable and multivariable generalized linear models. RESULTS: Cemented femoral stem THA generated 1.080 times (95% confidence interval, 1.06 to 1.10; P < .001), or 8.0%, greater index hospital costs than cementless femoral stem THA, and cemented femoral stem HA generated 1.042 times (95% confidence interval, 1.03 to 1.05; P < .001), or 4.2%, greater index hospital costs than cementless femoral stem HA. CONCLUSIONS: Cemented femoral stems for FNF treated with either THA or HA are associated with only a small portion of increased cost compared to cementless femoral stems. Providers may choose the method of arthroplasty stem fixation for the treatment of FNF based on what they deem most appropriate for the specific patient.

Community Readiness Assessment of the "Take TIME for Your Child's Health" Intervention.

Take TIME (Tobacco-free, Injury-free, Moving daily, Eating healthy) was an early intervention strategy targeting community readiness to support healthy lifestyles for young children in Uxbridge, Canada. This study aimed to assess the effectiveness of Take TIME using the Community Readiness Model adapted for childhood obesity prevention. Six interviews were completed in Uxbridge, before and after the intervention, with purposively selected community leaders in education, political, business, religious, not-for-profit, and healthcare fields. Each interview was rated independently by two scorers. Interview content was scored (scale from 1 to 9, with 1 being no awareness and 9 being a high level of community ownership) according to the Community Readiness Model criteria on six dimensions, with overall readiness calculated as the mean score of all dimensions. T-tests compared readiness by time-point and between communities. Overall community readiness significantly improved (p = 0.03) in Uxbridge from pre-intervention (3.63 ± 1.14 vague awareness) to post-intervention (5.21 ± 0.97 preparation). Seven interviews were also completed with leaders in the matched town of Rockwood, Canada which served as the control community. Rockwood readiness was close to the Uxbridge post-intervention score (5.35 ± 1.11). Results indicated increased awareness and leadership support post-intervention in Uxbridge, but further improvements in community knowledge, formalized efforts, and additional leadership support are desired. Take TIME increased community readiness to support healthy lifestyles for young children and may be useful to other communities at similar stages, given its theoretical alignment with the community readiness model. Future research should investigate the impact of Take TIME in demographically diverse communities and appropriate interventions to move communities from the preparation to the action stage.

Maintenance of an Intraoperative External Fixator Is Associated With Decreased Postoperative Stiffness After Definitive Management of High-Energy Tibial Plateau Fractures.

Introduction Postoperative stiffness is a common complication after high-energy tibial plateau fractures. Investigation into reported surgical techniques for the prevention of postoperative stiffness is limited. The purpose of this study was to compare the rates of postoperative stiffness after second-stage definitive surgery for high-energy tibial plateau fractures between groups of patients who had the external fixator prepped into the surgical field and those who did not. Methods Two hundred forty-four patients met the inclusion criteria between the two academic Level I trauma centers, representing the retrospective observational cohort. Patients were separated based on prepping of the external fixator into the surgical field during second-stage definitive open reduction and internal fixation. One hundred sixty-two patients were in the prepped group and 82 were in the non-prepped group. Post-operative stiffness was determined by the need to return to the operating room for subsequent procedures. Results At the final follow-up (mean = 14.6 months), patients in the non-prepped group had an increased rate of stiffness post-operatively (18.3% non-prepped versus 6.8% prepped; p = 0.006). No other investigated variables were associated with increased post-operative stiffness, including the number of days spent in the fixator and operative time. The relative risk for post-operative stiffness associated with complete fixator removal was 2.54 (95% CI 1.26-4.41; p = 0.008 on binary logistic regression; absolute risk reduction 11.5%). Conclusion At the final follow-up, maintenance of an intraoperative external fixator as a reduction aid was associated with a clinically significant decrease in post-operative stiffness after definitive management of high-energy tibial plateau fractures, when compared with complete removal prior to prepping.

Perioperative allogenic blood transfusions are associated with increased fracture related infection rates, but not nonunion in operatively treated distal femur fractures.

INTRODUCTION: Distal femur fractures are common injuries that remain difficult for orthopedic surgeons to treat. High complication rates, including nonunion rates as high as 24% and infection rates of 8%, can lead to increased morbidity for these patients. Allogenic blood transfusions have previously been identified as risk factors for infection in total joint arthroplasty and spinal fusion surgeries. No studies have explored the relationship between blood transfusions and fracture related infection (FRI) or nonunion in distal femur fractures. METHODS: 418 patients with operatively treated distal femur fractures at two level I trauma centers were retrospectively reviewed. Patient demographics were collected including age, gender, BMI, medical comorbidities, and smoking. Injury and treatment information was also collected including open fracture, polytrauma status, implant, perioperative transfusions, FRI, and nonunion. Patients with less than three months of follow up were excluded. RESULTS: 366 patients were included in final analysis. One hundred thirty-nine (38%) patients received a perioperative blood transfusion. Forty-seven (13%) nonunions and 30 (8%) FRI were identified. Allogenic blood transfusion was not associated with nonunion (13% vs 12%, P = 0.87), but was associated with FRI (15% vs 4%, P<0.001). Binary logistic regression analysis identified a dose dependent relationship between number of perioperative blood transfusions and FRI: total transfusion ≥2 U PRBC RR= 3.47(1.29, 8.10, P = 0.02), ≥3 RR= 6.99 (3.01, 12.40, P<0.001), and ≥4 RR= 8.94 (4.03, 14.42, P<0.001). DISCUSSION: In patients undergoing operative treatment of distal femur fractures, perioperative blood transfusions are associated with increased risk of fracture related infection, but not the development of a nonunion. This risk association increases in a dose-dependent relationship with increasing total blood transfusions received.

Mutations involving TGFB and MAPK may be associated with malignancy in granular cell tumors.

Granular cell tumors (GrCTs) are mesenchymal neoplasms of presumed schwannian differentiation that may present as solitary or multifocal lesions with excision usually being curative. A minority of cases, however, show histological features associated with an increased risk for metastasis and are highly aggressive leading to death in about a third of cases. While benign and malignant cases have been shown to harbor mutations in the H + ATPase genes, there is only limited data examining molecular aberrations associated with malignancy. The departmental archives were searched for cases of atypical/malignant GrCTs. Clinical and histopathological features were noted. Whole-exome sequencing was performed. Three cases of malignant GrCTs and one case of atypical GrCTs were included. All three malignant tumors metastasized to distant sites with a median disease-free survival of 16 months and an overall follow-up time of 35 months. Whole-exome sequencing showed mutations involving TGFß and MAPK pathways in all four tumors. Although the cohort size is small, our preliminary findings suggest that mutations involving the TGFß and MAPK pathways may be associated with tumor progression or malignant transformation in GrCT pathogenesis.

Molecular Characterization of Multifocal Granular Cell Tumors.

Granular cell tumors (GrCT) were recently found to be driven by inactivating mutations in vacuolar H + -ATPase (V-ATPase) genes, most frequently ATP6AP1 and ATP6AP2 . Multifocal presentation is present in ~10% of cases; however, the relationship between multifocal tumors in a given patient has not been elucidated. We hypothesized that benign-appearing multifocal GrCT are molecularly distinct whereas paired primary and metastatic malignant GrCT share identical mutations. To test this, we conducted targeted next-generation sequencing of the V-ATPase genes in multifocal GrCT and whole exome and Sanger sequencing in paired primary and metastatic malignant GrCT. Thirteen patients with≥2 GrCT were identified (total of 43 tumors). Forty-two tumors were successfully sequenced. Tumors showed somatic mutations in 3 of the 10 targeted genes in 32 of 42 samples (76%). Twenty tumors showed mutations in ATP6AP1 (48%), 10 tumors had mutations in ATP6AP2 (24%), and 2 tumors showed mutations in ATP6V0A4 (5%). Predicted loss-of-function mutations were found in ATP6AP1 in 17 tumors (40%), in ATP6AP2 in 10 tumors (24%), and in ATP6V0A4 in 1 tumor (2%). In 8 patients, mutually exclusive mutations were detected in at least 2 tumors per patient. Two patients were identified with malignant GrCT with material available from both primary and metastatic sites. Identical frameshift insertions were found in ATP6AP1 in 1 case and the second case showed identical nonsense mutations in ATP6AP1 . In conclusion, multifocal GrCT within an individual patient are molecularly distinct, while paired primary and metastatic GrCT share identical mutations.

Comparison of outcomes and operative course between septic and aseptic nonunion in long bones.

PURPOSE: The treatment of nonunion of long bones is difficult particularly in the presence of infection, which often involves staged surgical management. There is limited literature to compare the post operative course and outcomes of patients treated for septic versus aseptic nonunion. Thus, the purpose of this study was to determine if a difference exists between the number of surgical procedures, time to union, and rate of successful union for these two groups. METHODS: A retrospective cohort study was performed at a single tertiary care center. Patients suffering nonunion of the humerus, tibia and femur were included. Patient demographic data and characteristics of the post operative course were collected to include number and reason for repeat operations, antibiotic course, time to union, and development of a successful union. RESULTS: About 28 of 122 patients had septic nonunion. After diagnosis of nonunion, the septic group averaged 3.9 surgeries compared to 1.5 in the aseptic group (p < 0.001). There was no difference in the rate of successful union (79.8% versus 85.7%; p = 0.220), though the septic group took 129 days longer on average for successful union. (376 versus 247; p = 0.018). CONCLUSION: Septic nonunion of long bones is associated with the need for significantly more operations as well as time to union, though union rates remain similar. The identification of infection is critical for both the appropriate treatment as well as counseling patients on the expected post operative course.

Patients who have undergone total shoulder arthroplasty prefer greater surgeon involvement in shared decision making.

BACKGROUND: There has been a shift in medical decision making from a paternalist model to a shared decision-making (SDM) approach, described as a patient-physician relationship where both parties collaborate to arrive on an evidence-based treatment regimen that best suits the patient's needs and values. However, there is a scarcity in evidence regarding SDM in shoulder arthroplasty. The purpose of this study was to evaluate overall patient preference for SDM and determine demographic and socioeconomic factors related to SDM preference in those undergoing shoulder arthroplasty. METHODS: Patients aged 40-89 years who had undergone a total shoulder arthroplasty were enrolled. Two-part questionnaires were administered collecting patient demographic information and SDM subscale scores postoperatively. Bivariate and multivariate regression models were used to determine factors associated with SDM Total and subscale scores. RESULTS: A total of 125 patients (53 male; mean age, 69.5 ± 10.4 years) who had undergone primary total shoulder arthroplasty were included. The mean Total SDM score was -2.24 ± 1.9 and the Preoperative, Operative, and Postoperative SDM subscale scores were -1.54 ± 2.0, -2.59 ± 2.2, and -2.48 ± 2.1, respectively, indicating a preference for SDM in the Preoperative subscale and surgeon-driven decision making in the total score and other 2 subscales. Multivariate regression models demonstrated a preference for surgeon decision making at both the 4-12-week postoperative period for the Preoperative subscale (odds ratio [OR] -1.03, 95% CI -2.0, -0.1, P = .039) and the 2-4-week postoperative period for the Operative subscale (OR -1.74, 95% CI -3.4, -0.1, P = .038) when compared to patients at the 2-week postoperative period. No other variables were significantly associated with any of the SDM subscale scores or Total SDM score. CONCLUSION: Patients reported a more passive role in the decision-making process with an overall preference for a surgeon-led approach in primary total shoulder arthroplasty. Patients preferred a shared decision-making approach in regard to preoperative considerations but indicated a significant preference for surgeon-led decision making regarding day of surgery decisions. There were no correlations between SDM scores and age, sex, race, income, education level, insurance type, or treating surgeon. Overall, patients demonstrated a predilection for an SDM approach for preoperative considerations, contrary to those decisions associated with the day of surgery and postoperative care.

High-volume Arthroplasty Centers Are Associated With Lower Hospital Costs When Performing Primary THA and TKA: A Database Study of 288,909 Medicare Claims for Procedures Performed in 2019.

BACKGROUND: With bundled payments and alternative reimbursement models expanding in scope and scale, reimbursements to hospitals are declining in value. As a result, cost reduction at the hospital level is paramount for the sustainability of profitable inpatient arthroplasty practices. Although multiple prior studies have investigated cost variation in arthroplasty surgery, it is unknown whether contemporary inpatient arthroplasty practices benefit from economies of scale after accounting for hospital characteristics and patient selection factors. Quantifying the independent effects of volume-based cost variation may be important for guiding future value-based health reform. QUESTIONS/PURPOSES: We performed this study to (1) determine whether the cost incurred by hospitals for performing primary inpatient THA and TKA is independently associated with hospital volume and (2) establish whether length of stay and discharge to home are associated with hospital volume. METHODS: The primary data source for this study was the Medicare Provider Analysis and Review Limited Data Set, which includes claims data for 100% of inpatient Medicare hospitalizations. We included patients undergoing primary elective inpatient THA and TKA in 2019. Exclusion criteria included non-Inpatient Prospective Payment System hospitalizations, nonelective admissions, bilateral procedures, and patients with cancer of the pelvis or lower extremities. A total of 500,658 arthroplasties were performed across 2762 hospitals for 492,262 Medicare beneficiaries during the study period; 59% (288,909 of 492,262) of procedures were analyzed after the exclusion criteria were applied. Most exclusions (37% [182,733 of 492,262]) were because of non-Inpatient Prospective Payment System hospitalizations. Among the study group, 87% (251,996 of 288,909) of procedures were in patients who were 65 to 84 years old, 88% (255,415 of 288,909) were performed in patients who were White, and 63% (180,688 of 288,909) were in patients who were women. Elixhauser comorbidities and van Walraven indices were calculated as measures of patient health status. Hospital costs were estimated by multiplying cost-to-charge ratios obtained from the 2019 Impact File by total hospital charges. This methodology enabled us to use the large Medicare Provider Analysis and Review database, which helped decrease the influence of random cost variation through the law of large numbers. Hospital volumes were calculated by stratifying claims by national provider identification number and counting the number of claims per national provider identification number. The data were then grouped into bins of increasing hospital volume to more easily compare larger-volume and smaller-volume centers. The relationship between hospital costs and volume was analyzed using univariable and multivariable generalized linear models. Results are reported as exponential coefficients, which can be interpreted as relative differences in cost. The impact of surgical volume on length of stay and discharge to home was assessed using binary logistic regression, considering the nested structure of the data, and results are reported as odds ratios (OR). RESULTS: Hospital cost and mean length of stay decreased, while rates of discharge to home increased with increasing hospital volume. After controlling for potential confounding variables such as patient demographics, health status, and geographic location, we found that inpatient arthroplasty costs at hospitals with 10 or fewer, 11 to 100, and 101 to 200 procedures annually were 1.32 (95% confidence interval [CI] 1.30 to 1.34; p < 0.001), 1.17 (95% CI 1.17 to 1.17; p < 0.001), and 1.10 (95% CI 1.10 to 1.10; p < 0.001) times greater than those of hospitals with 201 or more inpatient procedures annually. In addition, patients treated at smaller-volume hospitals had increased odds of experiencing a length of stay longer than 2 days (OR 1.25 to 3.44 [95% CI 1.10 to 4.03]; p < 0.001) and decreased odds of being discharged to home (OR 0.34 to 0.78 [95% CI 0.29 to 0.86]; p < 0.001). CONCLUSION: Higher-volume hospitals incur lower costs, shorter lengths of stay, and higher rates of discharge to home than lower-volume hospitals when performing inpatient THA and TKA. These findings suggest that small and medium-sized regional hospitals are disproportionately impacted by declining reimbursement and may necessitate special treatment to remain viable as bundled payment models continue to erode hospital payments. Further research is also warranted to identify the key drivers of this volume-based cost variation, which may facilitate quality improvement initiatives at the hospital and policy levels.

External fixator pin placement during initial management of tibial plateau fractures: are there parameters to minimize pin-plate overlap?

PURPOSE: External fixator pin site overlap with definitive fixation implants (pin-plate overlap) has been identified as a risk factor for surgical site infection in tibial plateau fractures. Despite this, pin-plate overlap occurs in 24-38% of patients. This study sought to identify radiographic characteristics associated with pin-plate overlap to help minimize occurrences. METHODS: 283 patients at two Level I trauma centers were retrospectively reviewed. Radiographic measurements were recorded including fracture length, distance from fracture to proximal tibial pin site, and pin site distance-to-fracture (PSF) ratio. RESULTS: 70 (24.7%) cases of pin-plate overlap were identified. Pin-plate overlap was associated with increased fracture length (81.5 ± 32.1 mm vs 56.9 ± 26.1 mm, p < 0.001) and decreased distance from fracture to proximal tibial pin site (84.5 ± 37.1 mm vs 126.9 ± 35.8 mm). Pins placed greater than 100 mm and 150 mm from the fracture eliminated 36/70 (51%) and 67/70 (96%) pin-plate overlaps, respectively. Pins placed with a PSF ratio greater than 1.5 and 2.0 eliminated 47/70 (67%), and 57/70 (81%) of pin-plate overlaps, respectively. CONCLUSIONS: Longer fractures, pins closer to the fracture, and decreased PSF ratio were associated with overlap. Placing proximal tibial pins more than 100 mm from the fracture eliminated most pin-plate overlaps.

Do number and location of plates impact infection rates after definitive fixation of high energy tibial plateau fractures?

PURPOSE: Surgical trauma may confer additional infectious risk after operative fixation for high energy tibial plateau fractures. This study aims to determine the impact of plate number and location on infection rates after these injuries. METHODS: This retrospective cohort study completed at two level one trauma centers included patients who underwent staged fixation for a tibial plateau fracture between 2015 and 2019. Plate number and location (lateral, medial, posteromedial, and anterior quadrants) used in the definitive fixation construct were collected from post-operative radiographs. Deep infection rate was primary the outcome. RESULTS: A total of 244 patients met inclusion criteria. The overall infection rate was 13.9% (34/244). Infection rates increased with each additional quadrant utilized (8.0% one quadrant, 13.0% two quadrants, 27.3% three quadrants, 100% four quadrants; p < 0.001), independent of plate number, fracture severity, operative time, number of incisions, external fixator pin and plate construct overlap, and days in the external fixator on multivariate analysis. CONCLUSIONS: Infection risk increases with each quadrant utilized in the fixation of high energy tibial plateau fractures. Providers should attempt to limit the dissection of soft tissue for hardware placement in the fixation of these injuries to limit infection risk. LEVEL OF EVIDENCE: Level III, retrospective therapeutic study.

Effect of Smoking on Motor Recovery After Cervical American Spinal Injury Association Grade D Traumatic Spinal Cord Injury.

BACKGROUND: Smoking is a known neurotoxin that has been shown to negatively impact neurological function and recovery in multiple animal studies. Patients who smoke have been shown to have decreased rates of motor improvement, fusion, and overall successful outcomes after elective spinal surgery, but the effect of smoking on outcomes after traumatic spinal cord injury (TSCI) has not been demonstrated in prior literature. This study aims to investigate how smoking effects motor recovery after TSCI. METHODS: Using the National Spinal Cord Injury Statistical Center database, patients who underwent surgical management of American Spinal Injury Association grade D cervical TSCI between 2009 and 2016 were included. Patients were grouped by smoking or nonsmoking status. Overall total motor score and change in motor scores at rehabilitation admission, rehabilitation discharge, and 1-year follow-up visits were compared between groups. Multiple linear regression analysis was completed, including any possible confounding demographic or injury variables. RESULTS: A total of 152 patients (121 smokers and 31 nonsmokers) completed their 1-year follow-up interview and physical examination and were included in the study. There were no differences in motor score between groups at rehabilitation admission or discharge. Smokers had worse improvement in motor score at 1 year (7.99 nonsmokers vs 4.61 smokers; P = 0.019 on multivariate analysis) and worse overall total motor score at 1 year (94.0 nonsmokers vs 90.0 smokers; P = 0.018 on multivariate analysis) after controlling for confounders. CONCLUSIONS: These results indicate diminished motor recovery in patients who continue to smoke after TSCI. These patients should be targeted for aggressive smoking cessation and require intervention from providers and peers in order to maximize recovery after injury. CLINICAL RELEVANCE: This study demonstrates that smoking cessation may be beneficial for patients with cervical ASIA grade D spinal cord injury and may be a focus for providers of these patients.

Do Patients With Chronic Diabetes Have Worse Motor Outcomes After Cervical ASIA C Traumatic Spinal Cord Injury?

STUDY DESIGN: This was a level IV retrospective prognostic study. OBJECTIVE: The objective of this study was to determine if patients with chronic diabetes have worse functional outcomes and motor recovery after cervical traumatic spinal cord injury (TSCI). SUMMARY OF BACKGROUND DATA: Diabetes mellitus has multiple deleterious neurological effects and has been shown to worsen elective cervical spine surgery outcomes. Prior literature has scarcely characterized the impact of chronic diabetes on motor and functional outcomes after TSCI. METHODS: The National Spinal Cord Injury Statistical Center (NSCISC) database was utilized to retrospectively collect data on cervical American Spinal Injury Association (ASIA) C TSCI between 2011 and 2016. Patients were divided into diabetes and nondiabetes groups. Primary outcomes included wheelchair requirement and ambulatory status 1 year after injury. Secondary outcomes were motor score collected at the time of rehab admission, rehab discharge, and 1-year follow-up. All outcome variables were analyzed using univariate and multivariate regression to assess for differences between diabetes and nondiabetes groups and possible confounders. RESULTS: A total of 219 patients met the inclusion criteria for the study: 193 without diabetes and 26 with diabetes (12.0%). After controlling for confounders, patients with diabetes had had significantly increased wheelchair requirement (83.3% vs. 51.8%, relative risk=1.63, 95% confidence interval: 1.20-1.83, P =0.009 multivariate) and decreased ambulatory rates (50% vs. 67.9%, relative risk=0.55, 95% confidence interval: 0.25-0.98, P =0.042 multivariate) at 1 year. They also had no difference in average total motor scores at rehab admission but significantly worse total motor scores at rehab discharge (50.6±23.3 vs. 60.3±21.4, P =0.033 univariate, P =0.002 multivariate). CONCLUSIONS: Patients with diabetes have increased wheelchair requirement and decreased ambulatory ability at 1 year after the injury as well as diminished recovery in motor scores after motor-incomplete cervical TSCI. These patients may be targets for aggressive diabetic screening and intervention to minimize negative outcomes.

Are Infection Rates Increased After Sterilization of the External Fixator During Staged Internal Fixation of High-Energy Tibial Plateau Fractures?

OBJECTIVES: To compare infection rates after second-stage definitive surgery for high-energy tibial plateau fractures between groups of patients who had the external fixator prepped into the surgical field and those who did not. DESIGN: Retrospective cohort study. SETTING: Two academic Level 1 trauma centers. PATIENTS/PARTICIPANTS: Two hundred forty-four patients met inclusion and exclusion criteria between the 2 institutions. INTERVENTION: Prepping of the external fixator into the surgical field during second-stage definitive open reduction and internal fixation. 162 patients were in the prepped group, and 82 patients were in the nonprepped group. MAIN OUTCOME MEASUREMENTS: The primary outcome was the rate of deep infection after definitive fixation. Secondary outcome was operative time. RESULTS: There were no significant differences in infection rates between prepped (11.7%) and nonprepped (18.3%) groups ( P = 0.162). Patients in the prepped groups had significantly decreased operative time (168.2 minutes vs. 221.9 minutes, P < 0.001) even after controlling for confounders in regression analysis. CONCLUSIONS: There is no increased risk of infection associated with prepping and maintenance of the external fixator during definitive internal fixation for high-energy tibial plateau fractures. These data suggest that this practice may lead to shorter operative times as well. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Hepatic Thermal Ablation: Effect of Device and Heating Parameters on Local Tissue Reactions and Distant Tumor Growth.

Purpose To determine whether variable hepatic microwave ablation (MWA) can induce local inflammation and distant pro-oncogenic effects compared with hepatic radiofrequency ablation (RFA) in an animal model. Materials and Methods In this institutional Animal Care and Use Committee-approved study, F344 rats (150 gm, n = 96) with subcutaneous R3230 breast adenocarcinoma tumors had normal non-tumor-bearing liver treated with RFA (70°C × 5 minutes), rapid higher-power MWA (20 W × 15 seconds), slower lower-power MWA (5 W × 2 minutes), or a sham procedure (needle placement without energy) and were sacrificed at 6 hours to 7 days (four time points; six animals per arm per time point). Ablation settings produced 11.4 mm ± 0.8 of coagulation for all groups. Distant tumor growth rates were determined to 7 days after treatment. Liver heat shock protein (HSP) 70 levels (at 72 hours) and macrophages (CD68 at 7 days), tumor proliferative indexes (Ki-67 and CD34 at 7 days), and serum and tissue levels of interleukin 6 (IL-6) at 6 hours, hepatocyte growth factor (HGF) at 72 hours, and vascular endothelial growth factor (VEGF) at 72 hours after ablation were assessed. All data were expressed as means ± standard deviations and were compared by using two-tailed t tests and analysis of variance for selected group comparisons. Linear regression analysis of tumor growth curves was used to determine pre- and posttreatment growth curves on a per-tumor basis. Results At 7 days, hepatic ablations with 5-W MWA and RFA increased distant tumor size compared with 20-W MWA and the sham procedure (5-W MWA: 16.3 mm ± 1.1 and RFA: 16.3 mm ± 0.9 vs sham: 13.6 mm ± 1.3, P < .01, and 20-W MWA: 14.6 mm ± 0.9, P < .05). RFA and 5-W MWA increased postablation tumor growth rates compared with the 20-W MWA and sham arms (preablation growth rates range for all arms: 0.60-0.64 mm/d; postablation: RFA: 0.91 mm/d ± 0.11, 5-W MWA: 0.91 mm/d ± 0.14, P < .01 vs pretreatment; 20-W MWA: 0.69 mm/d ± 0.07, sham: 0.56 mm/d ± 1.15; P = .48 and .65, respectively). Tumor proliferation (Ki-67 percentage) was increased for 5-W MWA (82% ± 5) and RFA (79% ± 5), followed by 20-W MWA (65% ± 2), compared with sham (49% ± 5, P < .01). Likewise, distant tumor microvascular density was greater for 5-W MWA and RFA (P < .01 vs 20-W MWA and sham). Lower-energy MWA and RFA also resulted in increased HSP 70 expression and macrophages in the periablational rim (P < .05). Last, IL-6, HGF, and VEGF elevations were seen in 5-W MWA and RFA compared with 20-W MWA and sham (P < .05). Conclusion Although hepatic MWA can incite periablational inflammation and increased distant tumor growth similar to RFA in an animal tumor model, higher-power, faster heating protocols may potentially mitigate such undesired effects. © RSNA, 2016.

Design of a dual slot antenna for small animal microwave ablation studies.

This study presents the development of a dual-slot antenna for small animal tumor ablation. By using a dual-slot design at 8 GHz, it was hypothesized that smaller and more spherical ablations can be produced. After computer-aided design optimization, antennas were fabricated and ablations performed at 5-20 W for 15-120 s with the objective of creating ablations with a diameter/length aspect ratio of at least 0.9. The new dual-slot design at 8 GHz created significantly more spherical ablations than a commercial antenna at 2.45 GHz in ex vivo liver tissue (Average Aspect Ratio 0.8081 vs. 0.4532, p <;<; 0.05). In vivo studies confirmed the highly spherical results ex vivo. Initial testing shows that the dual-slot antenna and 8 GHz generator can be used to ablate tumors in mice.