We studied the diffusion of nanoparticles (NPs) within aqueous entangled solutions of polyethylene oxide (PEO) by using two different optical techniques. Fluorescence correlation spectroscopy, a method widely used to investigate nanoparticle dynamics in polymer solution, was used to measure the long-time diffusion coefficient (D) of 25 nm radius particles within high molecular weight, Mw = 600 kg/mol PEO in water solutions. Differential dynamic microscopy (DDM) was used to determine the wave-vector dependent dynamics of NPs within the same polymer solutions. Our results showed good agreement between the two methods, including demonstration of normal diffusion and almost identical diffusion coefficients obtained by both techniques. The research extends the scope of DDM to study the dynamics and rheological properties of soft matter at a nanoscale. The measured diffusion coefficients followed a scaling theory, which can be explained by the coupling between polymer dynamics and NP motion.

Background: The deep inferior epigastric perforator flap for breast reconstruction is associated with lengthy operative times that remain an issue for plastic surgeons today. The main objective of this study was to determine if a 2-stage deep inferior epigastric perforator flap reconstruction resulted in a shorter total plastic surgeon operative time compared with an immediate reconstruction. Methods: A retrospective chart review was conducted on all patients who underwent deep inferior epigastric perforator flap breast reconstruction from February 2013 to July 2020 by the senior author. Patient demographics, medical comorbidities, mastectomy characteristics, expander placement, reconstructive procedures, operative time, and complications were tabulated. Results: The study included a total of 128 patients. For immediate/1-stage flap reconstruction, average operative times for the plastic surgeon were 427.0 minutes for unilateral procedures, and 506.3 minutes for bilateral procedures. For delayed/2-stage reconstruction, average combined plastic surgeon operative times were 351.1 minutes for unilateral expander followed by flap reconstruction (75.9 minutes shorter than immediate unilateral, P = 0.007), and 464.8 minutes for bilateral reconstruction (41.5 minutes shorter than immediate bilateral, P = 0.04). Total patient time under anesthesia was longer for 2-staged bilateral reconstruction ( P = 0.0001), but did not differ significantly for unilateral reconstruction. Complications between immediate and delayed groups were not significantly different. Conclusions: We found that staged reconstruction over 2 procedures resulted in a significant reduction in operative time for the plastic surgeon for both unilateral and bilateral reconstruction. With amenable breast surgeons and patients, the advantages of controlling scheduling and the operating room may encourage plastic surgeons to consider performing free flap reconstruction in a delayed fashion.

Background: Despite advancements in surgical and rehabilitation strategies, extremity amputations are frequently associated with disability, phantom limb sensations, and chronic pain. Investigation into potential treatment modalities has focused on the pathophysiological changes in both the peripheral and central nervous systems to better understand the underlying mechanism in the development of chronic pain in persons with amputations. Methods: Presented in this article is a discussion outlining the physiological changes that occur in the peripheral and central nervous systems following amputation. In this review, the authors examine the molecular and neuroplastic changes occurring in the nervous system, as well as the state-of-the-art treatment to help reduce the development of postamputation pain. Results: This review summarizes the current literature regarding neurological changes following amputation. Development of both central sensitization and neuronal remodeling in the spinal cord and cerebral cortex allows for the development of neuropathic and phantom limb pain postamputation. Recently developed treatments targeting these pathophysiological changes have enabled a reduction in the severity of pain; however, complete resolution remains elusive. Conclusions: Changes in the peripheral and central nervous systems following amputation should not be viewed as separate pathologies, but rather two interdependent mechanisms that underlie the development of pathological pain. A better understanding of the physiological changes following amputation will allow for improvements in therapeutic treatments to minimize pathological pain caused by amputation.

Electric scooters are an increasingly common and convenient mode of transportation worldwide and have effectively revolutionized the shared micromobility industry. As electric scooter sharing companies have increased in popularity there has been a concomitant increase in the frequency of all electric scooter-related injuries. The purpose of this study is to describe the most up-to-date trends in craniofacial fractures and lacerations related to electric scooter use among all age groups. We queried the National Electronic Injury Surveillance System (NEISS) for craniofacial fractures and lacerations related to e-scooters between 2010 and 2019. We then compared injury trends over time and between time periods before and after 2017 when electric scooter share apps revolutionized micromobility. We compared incidence of injury overall and by day of the week, patient demographics, and case severity based on clinical disposition. We identified an increase in the frequency of craniofacial lacerations and fractures in the 3 years following the introduction of electric scooter share services in 2017 (2017 and 2019), compared to the 3 years before this time (2014-2016). Young adults (18-39 years) were the age group with the greatest interval increase in craniofacial injuries. There was also an increase in number of craniofacial injuries occurring on Mondays and a decrease number occurring on Fridays in the later time period. Finally, patients who presented with electric scooter-related craniofacial injuries in this later time period showed a higher frequency of overnight observation and hospital admission for their injuries. The number of craniofacial injuries secondary to electric scooter use has increased dramatically since the introduction of share services. Craniofacial fractures and lacerations are a common reason for craniofacial or maxillofacial surgery consultation and understanding these patterns of injury will help prepare surgeons for patient care, preventative education, and public advocacy.

Background: Insurance coverage for microsurgical lymphatic surgery continues to be sporadic, as the procedures continue to be labeled investigational. The objective of this study was to examine the typical payment patterns of our clinical practice for microsurgical lymphatic procedures. Methods: We performed a single center, single surgeon retrospective case review for all lymphovenous bypass and vascularized lymph node transfer cases preformed from 2018 to 2020. We then queried the available financial data and calculated total charges, total paid by insurance, total variable cost (cost to the hospital), and the contribution margin (difference between the amount paid and variable cost). Descriptive statistics were then collected for each subgroup for analysis. Results: Financial data were collected on 22 patients with 10 left-sided, 11 right-sided and one bilateral procedure performed. Seven procedures were done prophylactically, and 15 were done for existing lymphedema. An estimated 10 of 22 patients (45%) had Medicare, Medicaid, or Tricare, with the remaining having private insurance. We calculated an average cost of $48,516.73, with average payment of $10,818.68, average variable cost of $5,567.10, for a contribution margin of +$5251.58. Conclusions: Lymphedema remains a common complication of surgery and a significant cost burden to patients and the healthcare system. Microsurgical procedures offer several advantages over medical therapy. In our practice, we were routinely reimbursed for both prophylactic and therapeutic procedures with positive contribution margins for the hospital and ratios similar to other surgeries. Despite the limitations of a small retrospective review, there is no similar published cost analysis data in the current literature.