Device safety assessment of bronchoscopic microwave ablation of normal swine peripheral lung using robotic-assisted bronchoscopy.

INTRODUCTION: The aim of this study was to assess the safety of bronchoscopic microwave ablation (MWA) of peripheral lung parenchyma using the NEUWAVE™ FLEX Microwave Ablation System, and robotic-assisted bronchoscopy (RAB) using the MONARCH™ Platform in a swine model. METHODS: Computed tomography (CT)-guided RAB MWA was performed in the peripheral lung parenchyma of 17 Yorkshire swine (40-50 kg) and procedural adverse events (AEs) documented. The acute group (day 0, n = 5) received 4 MWAs at 100 W for 1, 3, 5, and 10 min in 4 different lung lobes. Subacute and chronic groups (days 3 and 30, n = 6 each) received one MWA (100 W, 10 min) per animal. RESULTS: The study was completed without major procedural complications. No postprocedural AEs including death, pneumothorax, bronchopleural fistula, hemothorax, or pleural effusions were observed. No gross or histological findings suggestive of thromboembolism were found in any organ. One 3-Day and one 30-Day swine exhibited coughing that required no medication (minor AEs), and one 30-Day animal required antibiotic medication (major AE) for a suspected lower respiratory tract infection that subsided after two weeks. CT-based volumetric estimates of ablation zones in the acute group increased in an ablation time-dependent (1-10 min) manner, whereas macroscopy-based estimates showed an increasing trend in ablation zone size. CONCLUSION: The NEUWAVE FLEX and MONARCH devices were safely used to perform single or multiple RAB MWAs. The preclinical procedural safety profile of RAB MWA supports clinical research of both devices to investigate efficacy in select patients with oligometastatic disease or primary NSCLC.

Multimodal Pain Management of Femoral Neck Fractures Treated With Hemiarthroplasty.

The purpose of this study was to evaluate a multimodal pain management program incorporating periarticular injections of liposomal bupivacaine after hemiarthroplasty treatment of femoral neck fractures. This retrospective study selected patients treated with periarticular injections of liposomal bupivacaine within the multimodal pain management program (LBUP) (n = 100) and a control group of patients treated without local infiltration (n = 78). Similar pain control was achieved between both groups from day 1 to day 4 postsurgery (min p = .392). Length of stay was significantly lower for LBUP patients (4.8 days vs. 5.7 days, p = .013), and LBUP patients were significantly more likely to be ambulatory at discharge (82% vs. 69%, p = .013). LBUP patients were also less likely to need the intensive care unit (4% vs. 14%, p = .027). The percentage of patients with at least one opioid-related adverse event was lower in the LBUP group (3% vs. 8%, p = .156) as was the 90-day mortality rate (2% vs. 8%, p = .069), but the differences were not statistically significant. (Journal of Surgical Orthopaedic Advances 28(1):58-62, 2019).

The economic significance of orthopaedic infections.

Musculoskeletal infections are a leading cause of patient morbidity and rising healthcare expenditures. The incidence of musculoskeletal infections, including soft-tissue infections, periprosthetic joint infection, and osteomyelitis, is increasing. Cases involving both drug-resistant bacterial strains and periprosthetic joint infection in total hip and total knee arthroplasty are particularly costly and represent a growing economic burden for the American healthcare system. With the institution of the Affordable Care Act, there has been an increasing drive in the United States toward rewarding healthcare organizations for their quality of care, bundling episodes of care, and capitating approaches to managing populations. In current reimbursement models, complications following the index event, including infection, are not typically reimbursed, placing the burden of caring for infections on the physician, hospital, or accountable care organization. Without the ability to risk-stratify patient outcomes based on patient comorbidities that are associated with a higher incidence of musculoskeletal infection, healthcare organizations are disincentivized to care for moderate- to high-risk patients. Reducing the cost of treating musculoskeletal infection also depends on incentivizing innovations in infection prevention.

Effects of the mold temperature on the mechanical properties and crystallinity of hydroxyapatite whisker-reinforced polyetheretherketone scaffolds.

Porous and bioactive polyetheretherketone (PEEK) scaffolds have potential to replace metallic scaffolds for biologic fixation of permanent implants adjacent to trabecular bone, such as interbody spinal fusion devices. The objective of this study was to investigate the effects of the mold temperature and PEEK powder on the mechanical properties and crystallinity of hydroxyapatite (HA) whisker-reinforced PEEK scaffolds prepared using compression molding and porogen leaching. Scaffolds were prepared at mold temperatures ranging 340-390°C with a 50 or 10 µm PEEK powder, 75 vol% porosity, and 20 vol% HA whiskers. Scaffold mechanical properties were evaluated in unconfined, uniaxial compression and the PEEK matrix crystallinity was measured using specular reflectance Fourier transform infrared spectroscopy. Increased mold temperature resulted in increased compressive modulus, yield strength, and yield strain, reaching a plateau at ~370°C. HA reinforcements were observed to be segregated between PEEK particles, which inhibited PEEK particle coalescence during compression molding at temperatures less than 365°C but also ensured that bioactive HA reinforcements were exposed on scaffold strut surfaces. Increased mold temperature also resulted in decreased PEEK crystallinity, particularly for scaffolds molded at greater than 375°C. The PEEK powder size exhibited relatively minor effects on the scaffold mechanical properties and PEEK crystallinity. Therefore, the results of this study suggested that HA-reinforced PEEK scaffolds should be compression molded at 370-375°C. The apparent compressive modulus, yield strength, and yield strain for scaffolds molded at 370-375°C was 75-92 MPa, 2.0-2.2 MPa, and 2.5-3.6%, respectively, which was within the range exhibited by human vertebral trabecular bone.

Do dynamic cement-on-cement knee spacers provide better function and activity during two-stage exchange?

BACKGROUND: Implantation of an antibiotic bone cement spacer is used to treat infection of a TKA. Dynamic spacers fashioned with cement-on-cement articulating surfaces potentially facilitate patient mobility and reduce bone loss as compared with their static counterparts, while consisting of a biomaterial not traditionally used for load-bearing articulations. However, their direct impact on patient mobility and wear damage while implanted remains poorly understood. QUESTIONS/PURPOSES: We characterized patient activity, surface damage, and porous structure of dynamic cement-on-cement spacers. METHODS: We collected 22 dynamic and 14 static knee antibiotic cement spacers at revision surgeries at times ranging from 0.5 to 13 months from implantation. For these patients, we obtained demographic data and UCLA activity levels. We characterized surface damage using the Hood damage scoring method and used micro-CT analysis to observe the internal structure, cracking, and porosity of the cement. RESULTS: The average UCLA score was higher for patients with dynamic spacers than for patients with static spacers, with no differences in BMI or age. Burnishing was the only prevalent damage mode on all the bearing surfaces. Micro-CT analysis revealed the internal structure of the spacers was porous and highly inhomogeneous, including heterogeneous dispersion of radiopaque material and cavity defects. The average porosity was 8% (range, 1%-29%) and more than ½ of the spacers had pores greater than 1 mm in diameter. CONCLUSIONS: Our observations suggest dynamic, cement-on-cement spacers allow for increased patient activity without catastrophic failure. Despite the antibiotic loading and internal structural inhomogeneity, burnishing was the only prevalent damage mode that could be consistently classified with no evidence of fracture or delamination. The porous structure of the spacers varied highly across the surfaces without influencing the material failure.

Characterization of PEEK biomaterials using the small punch test.

The small punch test is widely used to characterize the ductility and fracture resistance in metals and ceramics, when only a small volume of material is available. This study was conducted to investigate the suitability of the small punch test for characterizing polyetheretherketone (PEEK) polymeric biomaterials for changes in material grade, crystallinity, and molding process. The small punch test reproducibly characterized the mechanical behavior of PEEK and was able to distinguish differences induced by molding process alterations and annealing. Peak load was most sensitive to changes in crystallinity, grade, molding process, and increased with increasing crystallinity, but decreased with the addition of image contrast materials. The ultimate displacement was negatively correlated with crystallinity. Molding process conditions had the greatest influence on metrics of the small punch test, when compared with the effects of annealing and the addition of a radiopacifier. The results of this study validate the small punch test as a repeatable method for measuring the mechanical behavior of PEEK biomaterials.