1Clinical Professor, Orthopaedic Surgery, University of California, Irvine, Irvine, CA, USA 2Chief Executive Officer and President, SINTX Technologies, Salt Lake City, UT, USA B. S. Bal ✉, 2000 E. Broadway, #251, Columbia, MO 65201, USA, Email: [email protected] A note from the Editor-in-Chief: We are pleased to publish the next installment of “Medicolegal Sidebar” in Clinical Orthopaedics and Related Research®. The goal of this quarterly column is to encourage thoughtful debate about how the law and medicine interact, and how this interaction affects the practice of orthopaedic surgery. We welcome reader feedback on all of our columns and articles; please send your comments to[email protected]. Each author certifies that there are no funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article related to the author or any immediate family members. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request. Clinical Orthopaedics and Related Research® neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDA approval status, of any drug or device before clinical use. The opinions expressed are those of the writers and do not reflect the opinion or policy of CORR® or The Association of Bone and Joint Surgeons®.

The Advanced Particle-astrophysics Telescope (APT) is a mission concept of a next-generation space-based gamma-ray and cosmic-ray observatory. We present the simulation of the instrument performance of the Antarctic Demonstrator for APT (ADAPT), a proposed long-duration balloon instrument based on a small portion of the full APT detector. We construct a semianalytical model of the MeV-GeV background for ADAPT based on observations from previous high-altitude balloon experiments and simulations of the upper atmosphere. We find that the ADAPT background is dominated by the gamma-ray albedo of the earth’s atmosphere. In the presence of this background, we simulate a detector design based on a 45 cm × 45 cm detector composed of 8 thin layers of CsI:Na scintillators. We develop and optimize reconstruction algorithms for gamma-rays from a few hundreds of keV up to a few GeV energies. We present results of a complete off-line analysis to derive the best reconstruction methods. At photon energies from 30 MeV to a few GeV, ADAPT could provide degree-level to sub-degree-level observations of galactic and extragalactic gamma-rays with an effective area of above 0.05 m 2 . In the MeV regime, our simulation shows that ADAPT can achieve a degree-level localization accuracy for gamma-ray bursts down to about 1 MeV/cm 2 in the presence of the gamma-ray and cosmic-ray background. ADAPT would be able to detect a few GRBs during the planned Antarctic balloon flight.

1Chief Executive Officer and President, SINTX Technologies, Salt Lake City, UT, USA B. S. Bal ✉, 2000 E. Broadway, #251, Columbia, MO 65201, USA, Email: [email protected] A note from the Editor-in-Chief: We are pleased to publish the next installment of “Medicolegal Sidebar” in Clinical Orthopaedics and Related Research®. The goal of this quarterly column is to encourage thoughtful debate about how the law and medicine interact, and how this interaction affects the practice of orthopaedic surgery. We welcome reader feedback on all of our columns and articles; please send your comments to[email protected]. The author certifies that there are no funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article related to the author or any immediate family members. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request. The opinions expressed are those of the writers and do not reflect the opinion or policy of CORR® or The Association of Bone and Joint Surgeons®.

We characterize the performance of our computational pipeline for real-time gamma-ray burst (GRB) detection and localization aboard the Advanced Particle-astrophysics Telescope (APT) -- a space-based observatory for MeV to TeV gamma-ray astronomy -- and its smaller, balloon-borne prototype, the Antarctic Demonstrator for APT (ADAPT), whose scientific focus will be the detection of MeV transients. These instruments observe scintillation light from multiple Compton scattering and photoabsorption of gamma-ray photons across a series of CsI detector layers. We infer the incident angle of each photon's first scattering to localize its source direction to a Compton ring about the vector defined by its first two interactions, then intersect rings from multiple photons to identify the GRB's source direction. We first describe algorithmic improvements that enhance localization accuracy (measured in our previous GEANT4 model of APT) while running in under 0.5 seconds on a low-power ARMv8 processor -- fast enough to permit real-time redirection of other instruments for follow-up observations. We then study our pipeline's behavior using a model of the smaller ADAPT detector that incorporates realistic estimates of instrument noise and atmospheric background radiation. Adding \textit{SiPM-based edge detectors}, which gather more light from each scintillation, greatly benefits ADAPT's localization accuracy. We expect that ADAPT can localize normally-incident GRBs of fluence 1 MeV/cm$^2$ and 1-second duration to within 2-3 degrees at least 68\% of the time. The full APT instrument, with its larger detector area and lack of atmospheric background, should be substantially more accurate even on GRBs of fluence as low as 0.1 MeV/cm$^2$.

1Chief Executive Officer and President, SINTX Technologies, Salt Lake City, UT, USA B. S. Bal ✉, SINTX Technologies, 1885 West 2100 South, Salt Lake City, UT 84119, USA, Email: [email protected] A note from the Editor-in-Chief: We are pleased to publish the next installment of "Medicolegal Sidebar" in Clinical Orthopaedics and Related Research®. The goal of this quarterly column is to encourage thoughtful debate about how the law and medicine interact, and how this interaction affects the practice of orthopaedic surgery. We welcome reader feedback on all of our columns and articles; please send your comments to [email protected]. The author certifies that there are no funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article related to the author or any immediate family members. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request. The opinions expressed are those of the writers and do not reflect the opinion or policy of CORR® or The Association of Bone and Joint Surgeons®.

Medical-grade masks and N95 respirators containing non-woven fibers are designed to prevent the spread of airborne diseases. While they effectively trap respiratory droplets and aerosols, they cannot lyse entrapped pathogens. Embedded antimicrobial agents such as silver, copper, zinc, iodine, peptides, quaternary ammonium salts, or nanoparticles have been used to overcome this limitation. However, their effectiveness remains debatable because these materials can be toxins, allergens, irritants, and environmental hazards. Recently, silicon nitride (Si 3 N 4 ) was found to be a potent antipathogenic compound, and it may be an ideal agent for masks. In powder or solid form, it is highly effective in inactivating bacteria, fungi, and viruses while leaving mammalian tissue unaffected. The purpose of this study was to serially assess the antiviral efficacy of Si 3 N 4 against SARS-CoV-2 using powders, solids, and embedded nonwoven fabrics. Si 3 N 4 powders and solids were prepared using conventional ceramic processing. The “pad-dry-cure” method was used to embed Si 3 N 4 particles into polypropylene fibers. Fabric testing was subsequently conducted using industrial standards—ISO 18184 for antiviral effectiveness, ASTM F2299 and EN 13274-7 for filtration efficiency, EN 14683 for differential pressure drop, and ISO 18562-2 for particle shedding. A modification of ISO 18562-3 was also employed to detect ammonia release from the fabric. Antiviral effectiveness for Si 3 N 4 powders, solids, and embedded fabrics were 99.99% at ≤ 5 min, ~ 93% in 24 h, and 87% to 92% in 120 min, respectively. Results of the standard mask tests were generally within prescribed safety limits. Further process optimization may lead to commercial Si 3 N 4 -based masks that not only “catch” but also “kill” pathogenic microbes.

Background Degeneration of the lumbar spine is common in aging adults and reflects a significant morbidity burden in this population. In selected patients that prove unresponsive to non-surgical treatment, posterior lumbar fusion (PLF) surgery, with or without adjunctive transforaminal lumbar interbody fusion (TLIF) can relieve pain and improve function. We describe here the radiographic fusion rates for PLF versus TLIF, using an intervertebral spinal cage made of silicon nitride ceramic (chemical formula Si3N4). Methods This retrospective cohort analysis enrolled 99 patients from August 2013 to January 2017; 17 had undergone PLF at 24 levels, while 82 had undergone TLIF at 104 levels. All operations were performed by a single surgeon at one institution. Radiographic and clinical outcomes were compared between PLF and TLIF at 2 and 6 weeks and then at 3, 6, 12, and 24 months. Results TLIF patients fused at higher rates compared to PLF at the 3-month (38.5% vs. 8.3%, P=0.006), 6-month (78.7% vs. 35.0%, P<0.001) and 12-month time periods (97.9% vs. 81.3%, P=0.018), with no difference at 24 months (100% vs. 94.4%, P=0.102). Index level segmental motion was significantly less and intervertebral disc height was improved in TLIF over PLF at all follow up intervals. Foraminal height was only greater in early follow up periods (2 weeks, 6 weeks and 3 months). TLIF patients experienced lover rates of PI-LL mismatch which was maintained across long term follow-up. Pelvic tilt was lower following TLIF compared to PLF, with no differences in complication rates between study groups. Conclusions Our retrospective series demonstrated that TLIF performed with silicon nitride interbody cages led to earlier radiographic fusion, greater restoration of disc and foraminal height, increased segmental rigidity and improved sagittal alignment when compared to PLF alone.

Implant manufacturer sales representatives (reps) are a familiar presence in orthopaedic operating rooms (OR), especially during spine surgery and adult reconstructive operations. For some surgeons, a rep’s presence in the OR is essential during surgery to secure and replenish implants, to educate surgeons on new implant designs, and for discussions on how their orthopaedic surgery peers approach the same operation with their implants [2]. Regardless of how surgeons view the utility of reps in the OR, the rep model has come under scrutiny in recent years [2]. For critics, the rep-based system adds cost to an already-expensive system. Financial ties between orthopaedic surgeons and the implant industry have been well publicized, potentially leading to improper conduct by both reps and surgeons that may jeopardize patient safety and welfare [6, 9]. A 2021 investigation published by Kaiser Health News alleged that rep activities like giving surgeons technical advice in the OR about the use of their products or paying surgeons to promote their implants at medical conferences, have caused patient harm; certainly, those activities have been named in lawsuits [9]. Having a rep present in the OR without the patient’s consent can give rise to invasion of privacy claims. In one legal case from 1978 that involved particularly egregious misconduct, a hospital, circulating nurse, sales rep, and orthopaedic surgeon were charged with the crimes of assault and fraud for allowing the rep to scrub in on a hip replacement case, and then neglecting to mention this in the operative note [7]. During the COVID-19 pandemic, many hospitals restricted sales reps from accessing ORs, forcing reps to rely on remote interactions with surgeons instead. As elective surgery resumes, COVID-19 protocols have opened the door for those who want to keep reps out of the hospital entirely, citing unnecessary increased costs and exposure of the patient to increased infection risk from additional people in the OR [9]. These critics argue that hospitals should train their own staff to perform the functions previously covered by sales reps [9]. Although there have been numerous documented examples of inappropriate relationships between surgeons and reps [1, 6, 9], the rep model is backed by decades of legal precedent and is likely here to stay, albeit with a diminished or more defined role in the OR because of hospitals’ COVID-19 protocols. Medical Device Litigation In support of its position, the Kaiser Health News report [9] described a patient’s nerve injury caused during spinal decompression at a Texas hospital. The rep did not have the desired size of a vertebral interbody implant, necessitating implantation of a larger size that was in stock. Four days after the initial surgery, the implant was exchanged for the correct size, but the injury persisted. The lawsuit named the sales rep, among other parties, alleging negligence in not having the right size available. The legal action, according to Kaiser Health News, took direct aim at the sales network that orthopaedic device manufacturers have set up to promote their surgical hardware, and how that network can lead to patient injury from defective or wrong-sized implants [9]. Lawsuits charging surgeons and reps with incorrect implant size selection or improper implantation techniques often name the implant manufacturer as a defendant for negligence in the design, manufacture, or labeling of the device. However, implant manufacturers are generally in a favorable position in such cases because of a legal principle called federal preemption, which itself is based on the Supremacy Clause in the US Constitution. Preemption prohibits state courts from assuming any functions that are exclusively entrusted to the federal government. Since medical devices undergo rigorous review and approval by a federal agency (the FDA), federal preemption works to remove implant-related legal claims out of state courts to federal courts, where the manufacturer can assert FDA-approval status of the device as a defense. The preemption of claims and their adjudication in federal courts makes it hard for injured plaintiffs to recover, while reducing litigation costs and complexity for defendant manufacturers [1]. The Case Law Riegel v Medtronic Inc [8], is an illustrative case of how federal preemption works. Charles Riegel had a serious complication when a cardiac angioplasty catheter made by Medtronic Inc ruptured in his coronary artery. He sued Medtronic for negligence in a state court. Medtronic argued that Riegel could not bring these claims under New York law since they were preempted by Section 360k(a) of the Medical Device Amendments (MDA) to the Food, Drug, and Cosmetic Act. The MDA establishes a federal regulatory process for medical device safety, and no state may set requirements that differ from or add to the federal ones. One by one, each of the three levels of US federal courts agreed with Medtronic as the case moved through its appeals. The US District Court, the US Court of Appeals for the Second Circuit, and the US Supreme Court all were of the same mind: If a medical device has undergone premarket approval by federal regulators, allowing state court claims against such devices would be an impermissible violation of MDA’s preemption clause. Medtronic prevailed. Suing the Rep: A Viable Option? Since the Riegel ruling in 2008 [8], implant manufacturers have seen an increase in product liability claims arising from instructions, representations, and omissions of sales reps [1]. There is incentive to name a rep in product liability claims. Litigation that would otherwise be likely preempted by federal law may survive in a state court on the so-called parallel claim exception [5]. Plaintiffs’ lawyers use this workaround strategy to keep the case in the plaintiff-friendly venues of state courts. While courts have yet to define a bright line for when the parallel claim exception applies, the general sense is that the degree of involvement and responsibility of the rep in the OR is important. That said, certain types of claims have a greater likelihood of surviving preemption arguments than others. For example, in the 2011 case, James v Stryker [4], a failed pain pump led to injuries following shoulder arthroscopic surgery. One of the allegations was the promotion of off-label use of the pain pump by the sales rep. Stryker Inc filed a motion to have the lawsuit dismissed. In denying dismissal, the court noted that the rep had actively promoted the use of the pain pump for shoulder surgery, despite knowing that such use was off-label. The James ruling illustrates that the mere presence of the rep in the OR, where off-label use occurs, is not enough to overcome federal preemption. Instead, off-label promotion through actions, words, or even willful silence by the rep can survive preemption. In general, cases involving off-label use of a device are more likely to be successful in adding the rep as a defendant. In contrast, failure-to-warn cases generally end up absolving the sales rep of liability. Courts hold the surgeon solely responsible for reading instructions that come in the implant package and for knowing how to use a medical device correctly. In Hall v Horn Medical [3], decided a year after James, a surgeon implanted a spinal device without a bone graft when the package-insert instructions for use were clear that the device was to be used only with a bone graft. Complications led to a lawsuit, and the rep was named as a defendant, alleging a duty to advise the surgeon about the need for a bone graft. At trial, the surgeon even testified that the rep told him that the device could be used without a bone graft. The Court held that the decision to not use a bone graft was a medical decision, and as such, entirely the responsibility of the surgeon, even if the rep had made a misleading statement about bone graft use. As Hall illustrates, it is not the duty of the rep to warn or advise the surgeon about the proper use of a medical device, or how to perform a procedure. Likewise, the argument that a rep gave medical advice to the surgeon, and thereby engaged in the practice of medicine usually fails. Most court decisions in this area agree that rep statements and advice in the OR do not amount to the unauthorized practice of medicine [1]. Still, if the actions of the rep were egregious enough, it is possible that a court may see things differently, as suggested by at least one legal opinion. In Wilkerson v Christian [10], a surgeon performed radiofrequency ablation of benign liver tumors. During the operation, the radiofrequency generator device was entirely in control of the rep, who operated it under instructions of the surgeon. Complications led to patient death, and while the lawsuit was dismissed on the grounds that the case was brought after the statute of limitations had lapsed, the court was clearly disturbed: “Plaintiff alleged facts, in good faith, that raise serious questions about the propriety of sales representatives in the operating room. The gravity of Plaintiff’s allegations that a sales representative performed, or participated in, (the deceased’s) tumor ablation procedure is not lost on this court” [10]. Discussion Although these legal rulings generally absolve the sales rep, they also suggest that the courts closely scrutinize rep conduct to determine whether there is liability. Accordingly, hospital staff, surgeons, and implant manufacturers should have guidelines in place that clearly define the role of reps in the OR, such that reps can add value, while avoiding legal liability. Cost pressures on hospitals from the pandemic and pressures from lawsuits targeting reps may lead to a new supply chain model, where the rep either has a diminished role, a more virtual role, or is no longer an essential component in every implant case. In the current healthcare environment, surgeon reliance on sales reps should be limited to routine steps, such as checking implant inventory, having back-up implants, opening implant boxes, and related duties. Actions such as templating radiographs, selecting implant sizes, citing instructions-for-use information to the surgeon, and advice or input during surgery likely go beyond the scope of rep duties, regardless of an individual rep’s competence in these areas. To avoid invasion of privacy claims, the patient should be informed of the presence and purpose of the rep in the OR, with written, informed consent. The surgeon should always have complete control of the operation, even if input from the sales rep was sought. At the end of the day, as the legal cases described in this column show, medical decisions are the responsibility of the surgeon, not the sales rep.

Surface inactivation of human microbial pathogens has a long history. The Smith Papyrus (2600 ~ 2200 B.C.) described the use of copper surfaces to sterilize chest wounds and drinking water. Brass and bronze on doorknobs can discourage microbial spread in hospitals, and metal-base surface coatings are used in hygiene-sensitive environments, both as inactivators and modulators of cellular immunity. A limitation of these approaches is that the reactive oxygen radicals (ROS) generated at metal surfaces also damage human cells by oxidizing their proteins and lipids. Silicon nitride (Si3N4) is a non-oxide ceramic compound with known surface bacterial resistance. We show here that off-stoichiometric reactions at Si3N4 surfaces are also capable of inactivating different types of single-stranded RNA (ssRNA) viruses independent of whether their structure presents an envelop or not. The antiviral property of Si3N4 derives from a hydrolysis reaction at its surface and the subsequent formation of reactive nitrogen species (RNS) in doses that could be metabolized by mammalian cells but are lethal to pathogens. Real-time reverse transcription (RT)-polymerase chain reaction (PCR) tests of viral RNA and in situ Raman spectroscopy suggested that the products of Si3N4 hydrolysis directly react with viral proteins and RNA. Si3N4 may have a role in controlling human epidemics related to ssRNA mutant viruses.

Introduction Starting in 2009, my colleagues and I (SAG) working in Long Beach, CA, USA noticed an alarming increase in the number of instrumented spine fusions performed on industrially injured workers. These were all being done at a small local hospital that had recently changed ownership. Our subsequent inquiries led to a cautionary tale of greed and naïveté that resulted in more than a dozen otherwise reputable orthopaedic and neurological surgeons exchanging their OR scrub suits for prison jumpsuits. In 2013, The Wall Street Journal reported a multimillion-dollar kickback scheme involving Pacific Hospital of Long Beach and several other entities [1]. Dubbed “Operation Spinal Cap” by investigators [8], the practitioners who were subsequently arrested included my (SAG) professional cohorts. Each indicted surgeon had allegedly received a monetary kickback from the new hospital owner, leading to greater surgeon payment for procedures performed at the facility. Unfortunately, this type of news is hardly unique anymore. More recently, a Dallas judge sentenced three spine surgeons to 60- to 90-month prison terms for receiving unlawful kickbacks [12]. A few months after this ruling, an Austin, TX, USA hospital chain paid millions in fines for above-market-value on-call payments to orthopaedic surgeons and others who admitted patients to their facilities [14]. How do ostensibly well-educated individuals who have invested years in their education and training get ensnared in these criminal schemes? How can we avoid these scenarios, particularly as a profession that is dedicated to the welfare of our patients? Opportunity for Enticement Healthcare practitioners typically write an order that generates a service, which also triggers a payment for that service. In this fee-for-service model, to increase business, a vendor wants healthcare practitioners to choose its products or services over those of a competitor. Healthcare, however, is highly regulated and has generally uniform standards and practices, making it hard for competing vendors to differentiate their services. For example, many orthopaedic implants have improved over time to the point that they are nearly interchangeable [4]. Thus, an orthopaedic surgeon may view similar designs of hip replacement implants made by different manufacturers as virtually the same product. The pressure to successfully market one’s products can easily entice vendors to propose illegal business arrangements to practitioners. The fee-for-service model, lucrative profit margins, and the predictable efficacy and safety of modern medical devices together create a highly competitive business environment that is ripe for inducements to practitioners who direct patients to specific vendors. A surgeon may reason that choosing one hospital, imaging facility, or implant over another may be equally safe and efficacious for the patient. However, if that choice is driven by a financial inducement, then the public and its elected representatives are likely to take a dim view. The concern is that monetary inducements may lead to poor choices, driven by surgeon benefit over patient welfare. Accordingly, scandals involving improper physician referrals have led to the passing of criminal statutes and laws that seek to discourage such misconduct in the interests of society. Kickback Schemes and Drivers of Misconduct Kickback payments come in many forms. These can vary from greenback-stuffed manila envelopes, to team-colored sports tickets, to black and white contracts signed in blue ink (Table 1). To create the aura of legality, the Southern California scheme referenced at the top of this column created written agreements to indirectly funnel payments from the vendor to the practitioner. In one instance, the hospital owner sublet office space from a practitioner—ostensibly for storage needs—and disguised the kickback as a rental payment; the payment was well in excess of fair market rental values for comparable space [10, 11]. One neurosurgeon, sentenced to 15 months in a federal penitentiary, sold a monthly Option Purchase Agreement for his accounts receivable to the hospital in exchange for patient referrals [10]. Another participating orthopaedic surgeon, serving a 2 ½ year prison sentence, turned his office management functions over to the hospital owner, with a guaranteed minimum income that exceeded the surgeon’s earnings from performing surgeries [9]. Table 1. - Examples of disguised kickback arrangements Deal Description Management agreements Briber manages practitioner’s practice, guaranteeing income that exceeds present earnings. Sublease agreements Briber subleases space from practitioner for many-fold the footage’s fair market value. Above market value agreements Excessive payments to practitioners for ER coverage can disguise kickbacks. Employment services Briber provides salary-subsidized employees to referral sources. Purchase of accounts receivable Briber buys accounts receivables for more than their true value, absorbing write-offs. Gifts and travel Vendor lists kickback gifts as expenses, requesting reimbursement or a tax deduction. Marketing consultant Briber pays practitioner to help with marketing, disguising kickback as fees. Cross referrals Sending patients to service provider in exchange for reciprocal patient referrals. Professional component billing Vendor supplies service or goods below market value; practitioner bills difference. Financial desperation, dishonesty, and greed are the most likely drivers of financial misconduct by physicians [6]. The same may be true of white-collar crime in general. Physician naïveté may also play a role; blind trust in legal-appearing business documents describing complex management, sublease, and option agreements may lead to illicit arrangements. Ignorance of the law, while no excuse in a courtroom, may contribute to surgeons not seeking out independent legal advice from a reputable firm focused on white-collar criminal defense. Regardless of what factors lead to the misconduct, it is very disheartening to see familiar fellow professionals listed as defendants on a federal indictment, published online and in local newspapers, with attendant erosion of public trust and confidence in our profession. The Collateral Effects of Crime Unlike medical malpractice lawsuits that are familiar to physicians, and for which insurance policies serve as protection, criminal activity is not an insurable risk. By the time a prosecutor has filed an indictment and the physician first becomes aware that there is a problem, the government usually has enough evidence of misconduct to build a solid case. Practically, this means that unlike medical malpractice cases, which end up overwhelmingly in favor of physician defendants, once the government has a criminal indictment, the odds are heavily stacked against the physician defendant. Legal cases involving contracts, antitrust, and punitive damages show that courts and juries look very unfavorably upon professionals who are driven by greed, particularly when the defendant is in a high-paying occupational tier [7]. When a jury returns a guilty verdict, judges have little, if any, discretion in sentencing guidelines; leaving open the probability of life-long incarceration. Faced with these odds, most criminal defendants will enter a plea bargain, agreeing to serve a shorter time in prison with payment of monetary penalties, and otherwise helping the prosecutors. The collateral effects of a felony conviction are very damaging. The federal government defines a felony as a crime with a punishment of more than 1 year, regardless of whether the defendant actually serves that length of time. Upon conviction, professional licensing and credentialing will likely be impossible, along with membership in professional societies, leading to permanent career loss. Other unfavorable consequences of a felony conviction include the inability to vote in elections, to secure credit to rent or buy a home, to bill federal agencies for professional services, and even to apply for a job after release from prison. The government has wide powers to seize and auction off personal assets to satisfy monetary settlements. Legal fees for managing a criminal defense and plea-bargaining with the prosecutor toward the least burdensome outcome can be very steep. How to Curb Criminal Arrangements Familiarity with fraud and abuse laws should be part of residency training, possibly in the context of teaching moral reasoning [2]. In addition, new physicians should proactively learn about the legal environment in which they will spend their careers. Fraud and abuse laws include the False Claims Act, Civil Monetary Penalties Law, Physician Self-Referral Law, The Exclusion Authorities (dealing with exclusion or suspension under federal or state healthcare programs), and the Anti-Kickback Statute. These laws are described in more detail by the Office of Inspector General of the U.S. Department of Health & Human Services in a publication titled “A Roadmap for New Physicians;” a resource that should be reviewed periodically as part of one’s continued medical education [13]. Vigilance is especially important since criminal statutes can trap the unwary in a number of ways. For example, payments made with bank checks usually move across state borders to national clearinghouses; this can make a kickback payment into a federal crime as a procedural matter, leading to an FBI investigation and prosecution by a U.S. Attorney. Federal District Court judges have shown little patience for corrupt professionals; in one case, a judge issued a scathing order condemning a handful of physicians hired in a fee-for-diagnosis scheme by unscrupulous lawyers who were filing thousands of claims against manufacturers of grinding wheels and sandpaper [5]. Because each allegation of a kickback payment may be a separate crime, the cumulative effect of consecutive prison sentences can make plea bargaining the only realistic choice. Plea bargaining can also entail a defendant choosing to cooperate in exchange for a lesser sentence; in such instances, the defendant may disclose other parties involved in the criminal scheme, such that no party can avoid prosecution by slipping under the radar. While anti-kickback statutes vary in federal and state jurisdictions, and offer various safe harbors, a simple question to ask before entering a remunerative business agreement is whether payments would stop if patient referrals to the participating vendor or service provider were to cease. If so, the business agreement may be a kickback scheme in disguise, and should be reviewed by an independent law firm. If in doubt, another option is to proactively examine the published advisory opinions of the Office of Inspector General of the U.S. Department of Health & Human Services, or seek out an individual opinion pertaining to the business agreement in question. This due diligence, while time-consuming, may avoid a criminal charge down the road. Conclusion Orthopaedic surgeons invest years of study and work toward gaining the trust of society to be responsible stewards of public health. Society permits us to inflict deliberate surgical injury upon patients with the goal of improving their function, with no guarantees of success. Society also trusts us to order goods and services, paid for by the government and insurance companies, with the goal of driving patient welfare, rather than personal financial gain. While medical malpractice claims may be a concern for many surgeons, ultimately most such cases end up resolving in favor of the defendant. Financial damages, if any, are covered by liability insurance. But criminal misconduct is an entirely different matter. Such recklessness can trap the unwary surgeon who is driven by financial motives. Financial agreements that involve reciprocal conduct should always be reviewed by a reputable law firm that is familiar with fraud and abuse statutes, and if still in doubt, an advisory opinion as to the legality of the agreement should be sought from the Office of Inspector General of the U.S. Department of Health & Human Services.

Most structural bioceramics are comprised of metallic oxides such as alumina and zirconia. They are generally considered to be completely bioinert, but a non-oxide ceramic, silicon nitride, achieves equivalent levels of mechanical reliability while being bioactive. Silicon nitride can not only stimulate cellular proliferation but it is also antipathogenic with demonstrated efficacy against Gram-positive and Gram-negative bacteria, fungi, and viruses. In this work, three physical vapor deposition coatings with different Si:N ratios (silicon-rich, stoichiometric, and nitrogen-rich) were deposited on mirror-polished silica glass substrates. The coatings were characterized by spectroscopic and microscopic techniques and tested in vitro against E. coli and KUSA-A1 mesenchymal cells. Results showed that nitrogen-enriched SixNy has a strong antibacterial effect against E. coli and contributes to cellular proliferation while silicon-enriched SixNy stimulates the production of bone tissue, with higher indexes for mineralization and quality. These results suggest that SixNy's biological properties can be optimized for specific applications by carefully tuning its surface chemistry. (C) 2020 Elsevier Ltd. All rights reserved.

Previous studies using gram-positive and -negative bacteria demonstrated that hydrolysis of silicon nitride (Si3N4) in aqueous suspensions elutes nitrogen and produces gaseous ammonia while buffering pH. According to immunochemistry assays, fluorescence imaging, and in situ Raman spectroscopy, we demonstrate here that the antipathogenic surface chemistry of Si3N4 can be extended to polymethylmethacrylate (PMMA) by compounding it with a minor fraction (similar to 8 vol.%) of Si3N4 particles without any tangible loss in bulk properties. The hydrolytic products, which were eluted from partly exposed Si3N4 particles at the composite surface, exhibited fungicidal action against Candida albicans. Using a specific nitrative stress sensing dye and highly resolved fluorescence micrographs, we observed in situ congestion of peroxynitrite (ONOO-) radicals in the mitochondria of the Candida cells exposed to the PMMA/Si3N4 composite, while these radicals were absent in the mitochondria of identical cells exposed to monolithic PMMA. These in situ observations suggest that the surface chemistry of Si3N4 mimics the antifungal activity of macrophages, which concurrently produce NO radicals and superoxide anions (O-2(center dot-)) resulting in the formation of candidacidal ONOO-. The fungicidal properties of PMMA/Si3N4 composites could be used in dental appliances to inhibit the uncontrolled growth of Candida albicans and ensuing candidiasis while being synergic with chemoprophylaxis. Statement of significance In a follow-up of previous studies of gram-positive and gram-negative bacteria, we demonstrate here that the antipathogenic surface chemistry of Si3N4 could be extended to polymethylmethacrylate (PMMA) containing a minor fraction (similar to 8 vol.%) of Si3N4 particles without tangible loss in bulk properties. Hydrolytic products eluted from Si3N4 particles at the composite surface exhibited fungicidal action against Candida albicans. Highly resolved fluorescence microscopy revealed congestion of peroxynitrite (ONOO-) radicals in the mitochondria of the Candida cells exposed to the PMMA/Si3N4 composite, while radicals were absent in the mitochondria of identical cells exposed to monolithic PMMA. The fungicidal properties of PMMA/Si3N4 composites could be used in dental appliances to inhibit uncontrolled growth of Candida albicans and ensuing candidiasis in synergy with chemoprophylaxis. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.