A Prospective Randomized Pilot Study: One-Year Outcomes of Ligament Reconstruction Tendon Interposition Versus Suture Tape Suspensionplasty for Thumb Carpometacarpal Joint Arthritis.

PURPOSE: We performed a randomized controlled trial assessing patient-reported outcome measures following trapeziectomy with ligament reconstruction and tendon interposition (LRTI) or suture tape suspensionplasty (STS) for treatment of thumb carpometacarpal joint osteoarthritis. METHODS: Patients undergoing surgery for thumb carpometacarpal joint osteoarthritis were prospectively randomized to LRTI or STS. Outcome measures were collected at 2 weeks, 4 weeks, 3 months, and 1 year and included visual analog scale pain, Patient-Reported Outcomes Measurement Information System (PROMIS) Upper Extremity, return to work/activity, range of motion, grip/pinch strength, and complications. RESULTS: Thirty-one patients (32 thumbs) were randomized from 51 patients offered participation over two years. One-year follow-up was 97%. Both groups had a decrease in visual analog scale pain scores at all postoperative time points. The trajectory of postoperative Patient-Reported Outcomes Measurement Information System Upper Extremity scores was similar, and both groups achieved the meaningful clinically important difference for improvement in PROMIS Upper Extremity by three months. Grip strength was substantially increased in both groups at one year. Return to work/activity and surgical complications favored the LRTI group. CONCLUSIONS: Our study did not suggest any clinically relevant differences in the postoperative patient-reported outcome measures or objective clinical measurements between LRTI and STS, although LRTI patients had a faster return to work/activity and lower complication rates. TYPE OF STUDY/LEVEL OF EVIDENCE: Prospective randomized clinical trial, level IIB clinical.

Factors Influencing Patient Experience After Cubital Tunnel Syndrome Surgery.

PURPOSE: The purpose of this study was to use qualitative methodology to better understand patient experiences after cubital tunnel surgery, with the goal of identifying areas of improvement in delivery of care. METHODS: Patients who underwent surgery (in situ decompression or anterior transposition) for cubital tunnel syndrome within the last 12 months, which was performed by one of three fellowship-trained hand surgeons, were identified. Participants were invited to an interview regarding "their experiences with ulnar nerve surgery." An interview guide with semistructured, open-ended questions regarding the decision for surgery, treatment goals, and the recovery process was used. Interim data analyses were conducted to assess emerging themes, and interviews were continued until thematic saturation was achieved. RESULTS: Seventeen participants completed interviews; the mean age of study participants was 57 years, and 71% were women. The mean time between surgery and the interview was 6 months. Participants identified the following two key areas that could improve their surgical experience: (1) the need for detailed preoperative education about the surgery and recovery process, (2) and the importance of discussing treatment goals and expectations. Participants suggested providing both written and online resources to patients, including specific details about incision size and recovery process in education materials, and setting expectations for symptom resolution. CONCLUSIONS: Although the overall patient experience after cubital tunnel surgery was positive, participants noted that there is a need for providing improved educational resources and counseling before surgery. CLINICAL RELEVANCE: Addressing education and counseling needs before cubital tunnel surgery will help surgeons to improve delivery of care.

Catastrophic Health Care Expenditure Following Brachial Plexus Injury.

PURPOSE: Brachial plexus injuries (BPIs) are devastating to patients not only functionally but also financially. Like patients experiencing other traumatic injuries and unexpected medical events, patients with BPIs are at risk of catastrophic health expenditure (CHE) in which out-of-pocket health spending exceeds 40% of postsubsistence income (income remaining after food and housing expenses). The individual financial strain after BPIs has not been previously quantified. The purpose of this study was to assess the proportion of patients with BPIs who experience risk of CHE after reconstructive surgery. METHODS: Administrative databases were used from 8 states to identify patients who underwent surgery for BPIs. Demographics including age, sex, race, and insurance payer type were obtained. Inpatient billing records were used to determine the total surgical and inpatient facility costs within 90 days after the initial surgery. Due to data constraints, further analysis was only conducted for privately-insured patients. The proportion of patients with BPIs at risk of CHE was recorded. Predictors of CHE risk were determined from a multivariable regression analysis. RESULTS: Among 681 privately-insured patients undergoing surgery for BPIs, nearly one-third (216 [32%]) were at risk of CHE. Black race and patients aged between 25 and 39 years were significant risk factors associated with CHE. Sex and the number of comorbidities were not associated with risk of CHE. CONCLUSIONS: Nearly one-third of privately-insured patients met the threshold for being at risk of CHE after BPI surgery. CLINICAL RELEVANCE: Identifying those patients at risk of CHE can inform strategies to minimize long-term financial distress after BPIs, including detailed counseling regarding anticipated health care expenditures and efforts to optimize access to appropriate insurance policies for patients with BPIs.

The Influence of Psychosocial Factors on Disability and Expected Improvement Before Surgery for Adult Traumatic Brachial Plexus Injury.

PURPOSE: Psychosocial factors influence pain and recovery after extremity trauma and may be targets for early intervention. This may be of particular interest for patients with adult traumatic brachial plexus injury (BPI), given the broad and devastating impact of the injury. We hypothesized that there would be an association between depressive symptoms, anxiety, and pain interference with preoperative disability and expectations for improvement after BPI surgery. METHODS: We enrolled 34 patients into a prospective multicenter cohort study for those undergoing surgery for adult traumatic BPI. Before surgery, participants completed Patient-Reported Outcome Measurement Information System scales for pain interference, anxiety, and depressive symptoms, and a validated BPI-specific measure of disability and expected improvement. We performed Pearson correlation analysis between pain interference, anxiety symptoms, and depressive symptoms with (A) disability and (B) expected improvement. We created separate linear regression models for (A) disability and (B) expected improvement including adjustment for severity of plexus injury, age, sex, and race. RESULTS: Among 34 patients, there was a moderate, statistically significant, correlation between preoperative depressive symptoms and higher disability. This remained significant in a linear regression model adjusted for severity of plexus injury, age, sex, and race. There was no association between severity of plexus injury and disability. Depressive symptoms also were moderately, but significantly, correlated with higher expected improvement. This remained significant in a linear regression model adjusted for severity of plexus injury, age, sex, and race. CONCLUSIONS: Depressive symptoms are associated with greater disability and higher expected improvement before BPI surgery. Screening for depressive symptoms can help BPI teams identify patients who would benefit from early referral to mental health specialists and tailor appropriate expectations counseling for functional recovery. We did not find an association between severity of BPI and patient-reported disability, suggesting either that the scale may lack validity or that the sample is biased. LEVEL OF EVIDENCE: Prognostic II.

'Being a patient the rest of my life'- The influence of patient participation during recovery after brachial plexus injury.

BACKGROUND: Given the modest functional outcomes seen after surgical reconstruction and subsequent therapy, increasing attention is being directed to patient satisfaction and psychological aspects of recovery after brachial plexus injury (BPI). PURPOSE: To better understand the recovery course after surgical reconstruction for BPI, we used qualitative interviews and focused on common points of frustration for patients. STUDY DESIGN: Qualitative, interpretive description study METHODS: We conducted semi-structured interviews with BPI patients who were 6+ months post-surgical reconstruction. The interview focused on the patients' experience with BPI, focusing on emotional aspects of recovery. Interviews were transcribed and independently coded by 2 researchers. We used inductive and deductive analysis to organize codes into themes. Once thematic saturation was reached, no additional interviews were conducted. RESULTS: We interviewed 15 BPI patients at median 13 months after surgery (range: 6-43 months). Our analysis revealed: (1) BPI patients expressed variable degrees of participation during recovery, with the indeterminate state of function making it difficult to adjust to life after BPI. (2) The uncertainty while waiting for improved function is frustrating to BPI patients, with many patients expressing concern for activities and moments they are missing due to injury. (3) While many BPI patients feel left out of decision-making, those who felt engaged in the process expressed less frustration and more acceptance of their status. CONCLUSION: Traumatic BPI patients those who felt engaged in decision-making were more receptive to adjustment to their new state of function. When coordinating multidisciplinary care, measures to encourage patients to feel agency over their outcome and to develop self-management skills have the potential to improve patient satisfaction.

Development and Testing of a Novel Locking Pin Cap to Create a Fixed-Angle K-Wire Plate Construct.

PURPOSE: To test the effectiveness of a novel locking pin cap to attach a K-wire rigidly to a volar locking plate and resist fracture displacement compared with commercially available alternatives. METHODS: Two different methods of fracture fixation were tested on a total of 12 Sawbones models with volar shear distal radius fracture (6/group). The fragments were fixed with either 2 commercially available pin plates (industry standard) or a volar plate with 2 locking screws fixing the scaphoid facet and 2 pins locked to the plate with a novel locking pin cap in the lunate facet. Axial load conditioning was performed followed by sinusoidal loading to 250 N at 50 mm/s. A motion capture system was used to assess the relative movement of the fracture fragments relative to the intact shaft. The strength of the fixation construct was quantified by (1) the force required to achieve a 2-mm gap between the shaft and fracture fragments and (2) ultimate load to failure. RESULTS: One industry standard pin plate demonstrated disassociation of the pin from the plate after fatigue conditioning. This did not occur in the locking pin cap group. The locking pin cap construct group was able to sustain a significantly higher load compared with the industry standard when the construct was displaced to the 2-mm gap. The locking pin cap also significantly increased the ultimate load to failure compared with the industry standard. CONCLUSIONS: The novel locking pin cap creates a fixed-angle attachment of a K-wire to an existing locking screw hole in a plate. This fixed-angle K-wire is significantly stronger in preventing gap formation and resisting ultimate failure than commercially available plates that use bent K-wires. CLINICAL RELEVANCE: The development of novel techniques to secure small articular fragments may ultimately improve clinical outcomes.

Management of Adult Brachial Plexus Injuries.

Adult brachial plexus injuries result in profound functional deficits, debilitating pain, substantial mental health implications, and extensive economic impacts. Their initial evaluation includes a detailed physical examination, electrodiagnostic studies, advanced imaging, and patient counseling. A team-based approach, led by a peripheral nerve surgeon and including hand therapists, electrodiagnosticians, mental health experts, and pain-management specialists, is used to provide optimal longitudinal care during the lengthy recovery process. The options for the surgical management of brachial plexus injuries include exploration, neurolysis, nerve grafting, nerve transfer, free functional muscle transfer, tendon transfer, arthrodesis, and amputation. When treated within 6 months, the outcomes are favorable for the restoration of essential shoulder and elbow function. Free functional muscle transfer is a powerful tool to address elbow flexion and rudimentary grasp in both primary and delayed settings. The restoration of hand function remains a challenge for patients with complete brachial plexus injury. The purpose of this review is to summarize foundational concepts in diagnosis and management, discuss current trends and controversial topics, and address areas for future investigation.

Evolving Techniques in Peripheral Nerve Regeneration.

Reliable and robust peripheral nerve regeneration after a nerve injury and repair remains an elusive goal. A variety of strategies have been proposed to mitigate the effects of Wallerian degeneration (through molecular therapies), enhance axonal regeneration across the repair site (through electrical stimulation and gene therapy), and explore alternatives to suture coaptation (through the fusion of transected ends). Although most of these techniques are in their infancy, animal data and some clinical trials have demonstrated promise for improving the restoration of function after these devastating injuries.

Histologic and Functional Outcomes of Conduit Wrapping for Peripheral Nerve Repair: Early Results in a Rat Model.

BACKGROUND: The concept of utilizing a nerve conduit for augmentation of a primary nerve repair has been advocated as a method to prevent neural scarring and decrease adhesions. Despite clinical use, little is known about the effects of a nerve conduit wrapped around a primary repair. To better understand this, we investigated the histologic and functional effects of use of a nerve conduit wrapped around a rat sciatic nerve repair without tension. METHODS: Twenty Lewis' rats were divided into two groups of 10 rats each. In each group, unilateral sciatic nerve transection and repair were performed, with the opposite limb utilized as a matched control. In the first group, direct repair alone was performed; in the second group, this repair was augmented with a porcine submucosa conduit wrapped around the repair site. Sciatic functional index (SFI) was measured at 6 weeks with walking track analysis in both groups. Nonsurvival surgeries were then performed in all animals to harvest both the experimental and control nerves to measure histomorphometric parameters of recovery. Histomorphometric parameters assessed included total number of neurons, nerve fiber density, nerve fiber width, G-ratio, and percentage of debris. Unpaired t-test was used to compare outcomes between the two groups. RESULTS: All nerves healed uneventfully but compared with direct repair; conduit usage was associated with greater histologic debris, decreased axonal density, worse G-ratio, and worse SFI. No significant differences were found in total axon count or gastrocnemius weight. CONCLUSION: In the absence of segmental defects, conduit wrapping primary nerve repairs seem to be associated with worse functional and mixed histologic outcomes at 6 weeks, possibly due to debris from conduit resorption. While clinical implications are unclear, more basic science and clinical studies should be performed prior to widespread adoption of this practice.

Characterization of the Dorsal Ulnar Corner in Distal Radius Fractures in Postmenopausal Females: Implications for Surgical Decision Making.

PURPOSE: To characterize the dorsal ulnar corner fragment with regard to size and morphology using 3-dimensional software and computed tomography (CT) scans, as it presents in low-energy intra-articular distal radius fractures occurring in the female postmenopausal population. METHODS: A multicenter retrospective review was conducted to identify postmenopausal females with low-energy distal radius fractures treated surgically at level-1 trauma centers. Patients with low-energy injuries with preoperative CT scans were included. The Digital Imaging and Communications in Medicine (DICOM) data from CT scans were used to reconstruct intra-articular fracture patterns. The dorsal ulnar fragment was isolated in each CT scan and measured, then normalized based on lunate depth. RESULTS: Eighty patients met the inclusion criteria. The mean dimension measurements of the dorsal ulnar corner were dorsal surface height, 9.82 ± 5.02 mm (95% confidence interval [95% CI], 8.72-10.92); dorsal surface width, 9.06 ± 3.72 mm (95% CI, 8.25-9.88); articular surface width, 7.44 ± 3.92 mm (95% CI, 6.58-8.30); articular surface depth, 4.14 ± 2.39 mm (95% CI, 3.62-4.67). The mean lunate depth measurement (17.52 ± 1.48 mm) was used to normalize articular surface depth demonstrating that, on average, the dorsal ulnar corner comprises 23.6% of the articular surface ± 13.6% (95% CI, 20.7-26.6). CONCLUSIONS: The mean articular surface depth of the dorsal ulnar corner fragment in this study was less than 5 mm, accounting for approximately 24% of the volar-dorsal width of the distal radius at the lunate facet. CLINICAL RELEVANCE: These data expand current understanding of the morphology and size of the dorsal ulnar corner fracture fragment. If fixation of this fragment is a goal, surgeons may need to use longer screws that penetrate closer to the dorsal cortex than those required for extra-articular fractures or to consider alternative methods of fragment-specific fixation for adequate capture of this fragment.

Absence of the Pronator Quadratus Muscle Precluding Distal Nerve Transfer.

The branch of the anterior interosseous nerve to the pronator quadratus (PQ) is increasingly used as a donor nerve for end-to-end and reverse end-to-side nerve transfers. The anatomy of the PQ (and its nerve branch) is generally considered reliable in the absence of prior trauma. In this report, we describe a patient with an absent PQ despite intact clinical examination of other muscles supplied by the anterior interosseous nerve. The absence of the PQ precluded the use of its nerve as a donor nerve for transfer.

Frequency and Risk Factors for Prolonged Opioid Prescriptions After Surgery for Brachial Plexus Injury.

PURPOSE: We hypothesized that patients with preoperative opioid prescriptions and diagnoses of depression and anxiety would be at increased risk for prolonged opioid prescriptions after surgery for brachial plexus injury (BPI). METHODS: Using an administrative database of privately insured patients, we assembled a cohort of BPI surgery patients and a control group of non-BPI patients, matching for age, sex, and year. Pharmacy claims for prescriptions filled for opioids and neuropathic pain medications were examined 12 months before surgery to 180 days after surgery. The primary outcome was prolonged opioid prescription, defined as receiving a prescription 90 to 180 days after the index (BPI surgery or randomly selected date of service for controls). Multivariable regression was used to examine risk factors for postoperative opioid use, including diagnoses of depression, anxiety, drug abuse, tobacco use, and preoperative use of opioids and neuropathic pain medications. A subgroup analysis was performed for opioid-naive BPI patients between 30 days to 1 year before surgery. RESULTS: Among BPI surgery patients (n = 1,936), 27.7% had prolonged opioid prescriptions. Among opioid-naive BPI patients (n = 911), 10.8% had prolonged opioid prescriptions. In controls (n = 19,360), frequency of prolonged opioid prescriptions was 0.11%. Among all BPI patients, after adjustment for age and sex, predictors of prolonged postoperative opioid prescriptions in BPI patients were preoperative opioids, preoperative neuropathic pain medication use, histories of drug abuse, tobacco use, and anxiety. CONCLUSIONS: Prolonged postoperative opioids prescriptions after BPI reconstruction are higher than previous estimates among other surgical patients. In addition to establishing normative data among this population, our findings serve to increase awareness of risk factors for prolonged opioids after BPI reconstruction and encourage coordinated multidisciplinary care. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic II.

Barriers to Epineural Scarring: Role in Treatment of Traumatic Nerve Injury and Chronic Compressive Neuropathy.

The physiological limitations of neural regeneration make peripheral nerve surgery challenging to both the surgeon and the patient. Presence of nerve gaps and local wound factors may all influence outcome, suggesting that barriers to reduce perineural scarring, minimize fibrosis, and avoid ischemia would be beneficial. To examine the evidence supporting their use, we reviewed the autologous and commercially-available options for barriers against scarring around a nerve. Numerous clinical case series demonstrated the effectiveness and safety of local/rotational flaps and autologous vein wrapping when used in the presence of recurrent compressive neuropathy. Translational research in animal models supports the biocompatibility of commercially available nerve wraps following nerve repair. To date, there are no reports of clinical use of commercially available nerve wraps in acute nerve repair, but a growing number of case series demonstrate their effectiveness and safety in chronic compressive neuropathy. Limited clinical evidence exists to support the efficacy of vein or flap coverage in acute nerve repairs.

Snapping Triceps Syndrome.

Snapping triceps syndrome is a rarely diagnosed condition that can present with symptoms of ulnar neuritis or as an isolated problem itself. First described in 1970, this syndrome is minimally present in the literature with a few mechanistic studies, anatomical studies, radiological reports, and occasional case reports or series. In this article, we briefly review the literature, discuss potential causes and typical presentations of snapping triceps syndrome, and describe our operative technique. We also provide a representative case with intraoperative videos that illustrate the pathology and surgical treatment.

A critical analysis of the review on antimicrobial resistance report and the infectious disease financing facility.

Over the past year, two major policy initiatives have been introduced focusing on stimulating antibiotic development for human consumption. The European Investment Bank has announced the development of the Infectious Disease Financing Facility (IDFF) and the British government commissioned the Review on Antimicrobial Resistance, led by Jim O'Neill. Each constitutes a major effort by the European community to address the evolving crisis of antimicrobial resistance. Though both have similar goals, the approaches are unique and worthy of consideration.This manuscript utilizes a previously published framework for evaluation of antibiotic incentive plans to clearly identify the strengths and weaknesses of each proposal. The merits of each proposal are evaluated in how they satisfy four key objectives: 1) Improve the overall net present value (NPV) for new antibiotic projects; 2) Enable greater participation of Small to Medium Sized Enterprises (SME); 3) Encourage participation by large pharmaceutical companies; 4) Facilitate cooperation and synergy across the antibiotic market. The IDFF seeks to make forgivable loans to corporations with promising compounds, while the O'Neill group proposes a more comprehensive framework of early stage funding, along with the creation of a stable global market.Ultimately, the proposals may prove complementary and if implemented together may form a more comprehensive plan to address an impending global crisis. Substantial progress will only be made on these efforts if action is taken at an international level, therefore we recommend consideration of these efforts at the upcoming G20 summit.

Management of Severely Comminuted Distal Radius Fractures.

Distal radius fractures are among the most common fractures of the upper extremity. Indications for operative and nonsurgical management have evolved over time, as have fixation techniques. Volar locking plates are commonly used in the treatment of selected distal radius fractures such as low-energy or relatively uncomplicated fractures. They have limitations, however, in the management of highly comminuted fracture patterns and in polytrauma patients. In these patients, other methods ranging from spanning fixation to fragment-specific fixation have emerged as useful alternatives in the surgeon's armamentarium for treatment of these challenging fractures.

Development and Assessment of a Patient "Journey Guide" for Adult Traumatic Brachial Plexus Injury.

BACKGROUND: Patients with a traumatic brachial plexus injury (BPI) have previously identified the need for improved patient education tools, emphasizing the importance of communicating outcome expectations, providing attention to the emotional aspects of the injury and the treatment of pain, and acknowledging the needs of caregivers. We created a journey guide, a BPI-specific educational tool, to address these deficiencies. In this study, we determined the acceptability of the journey guide through surveys of and semistructured interviews with patients with a BPI. METHODS: The journey guide was created by a multidisciplinary team focusing on previously defined areas for the improvement of patient education and care delivery related to BPI. To assess the acceptability of the journey guide, we recruited 19 participants from the brachial plexus clinic of our institution and the United Brachial Plexus Network to complete a series of surveys and semistructured interviews. Participants completed surveys regarding their satisfaction with the journey guide, and we conducted semistructured interviews to assess patient BPI experiences and impressions of the journey guide and to seek feedback. Interview transcripts were qualitatively analyzed to determine common themes for improvement. RESULTS: A total of 19 participants with a mean age of 44.7 years were included. The cohort was predominantly male (13 participants) and White (16 participants). The mean time since BPI was 12.9 years, ranging from 2.0 to 39.7 years. On a visual analog scale, satisfaction with the journey guide was given a mean score of 8.4; expected usefulness when a patient is first injured, 8.7; potential for continued use, 7.3; and the fit for the BPI community, 8.8. Qualitative analysis demonstrated a primarily positive view of the guide and identified 4 major themes: (1) visuals and quotes improve clarity and engagement, (2) the journey guide would be most useful immediately following an injury, (3) the journey guide is an effective organizational tool, and (4) it is difficult to orient patients toward future hardships. CONCLUSIONS: The journey guide successfully filled a gap in the current care for BPI and was largely deemed acceptable by patients with a BPI. Specifically, participants found the journey guide to be a concise educational resource and an effective organizational tool. Participants also indicated that areas for improvement include the increased use of graphics and images and recognition of the greater BPI community with which patients can engage.

Biomechanical characterization of cadaveric brachial plexus microstructure.

INTRODUCTION: Peripheral nerves consist of axons and connective tissue. The amount of connective tissue in peripheral nerves such as the brachial plexus varies proximally to distally. The proximal regions of the brachial plexus are more susceptible to stretch injuries than the distal regions. A description of the mechanical behavior of the peripheral nerve components is necessary to better understand the deformation mechanisms during stretch injuries. The purpose of this study was to model the biomechanical behavior of each component of the peripheral nerves (fascicles, connective tissue) in a cadaveric model and report differences in elastic modulus, maximum stress and maximum strain. METHODS: Forty-six specimens of fascicles and epi-perineurium were subjected to cyclical uniaxial tensile tests to obtain the stress and strain histories of each specimen, using a BOSE® Electroforce® 3330 and INSTRON® 5969 materials testing machines. Maximum stress, maximum strain and elastic modulus were extracted from the load-displacement and stress-strain curves, and analyzed using Mann-Whitney tests. RESULTS: Mean elastic modulus was 6.34 MPa for fascicles, and 32.1 MPa for connective tissue. The differences in elastic modulus and maximum stress between fascicles and connective tissue were statistically significant (p < 0.001). CONCLUSIONS: Peripheral nerve connective tissue showed significantly higher elastic modulus and maximum stress than fascicles. These data confirm the greater fragility of axons compared to connective tissue, suggesting that the greater susceptibility to stretch injury in proximal regions of the brachial plexus might be related to the smaller amount of connective tissue.

Biomechanical characterization of cadaveric brachial plexus regions using uniaxial tensile tests.

INTRODUCTION: The proximal regions of the brachial plexus (roots, trunks) are more susceptible to permanent damage due to stretch injuries than the distal regions (cords, terminal branches). A better description of brachial plexus mechanical behavior is necessary to better understand deformation mechanisms in stretch injury. The purpose of this study was to model the biomechanical behavior of each portion of the brachial plexus (roots, trunks, cords, peripheral nerves) in a cadaveric model and report differences in elastic modulus, maximum stress and maximum strain. METHODS: Eight cadaveric plexi, divided into 47 segments according to regions of interest, underwent cyclical uniaxial tensile tests, using a BOSE® Electroforce® 3330 and INSTRON® 5969 material testing machines, to obtain the stress and strain histories of each specimen. Maximum stress, maximum strain and elastic modulus were extracted from the load-displacement and stress-strain curves. Statistical analyses used 1-way ANOVA with post-hoc Tukey HSD (Honestly Significant Difference) and Mann-Whitney tests. RESULTS: Mean elastic modulus was 8.65 MPa for roots, 8.82 MPa for trunks, 22.44 MPa for cords, and 26.43 MPa for peripheral nerves. Differences in elastic modulus and in maximum stress were statistically significant (p < 0.001) between proximal (roots, trunks) and distal (cords, peripheral nerves) specimens. CONCLUSIONS: Proximal structures demonstrated significantly smaller elastic modulus and maximum stress than distal structures. These data confirm the greater fragility of proximal regions of the brachial plexus.

Incentives for new antibiotics: the Options Market for Antibiotics (OMA) model.

BACKGROUND: Antimicrobial resistance is a growing threat resulting from the convergence of biological, economic and political pressures. Investment in research and development of new antimicrobials has suffered secondary to these pressures, leading to an emerging crisis in antibiotic resistance. METHODS: Current policies to stimulate antibiotic development have proven inadequate to overcome market failures. Therefore innovative ideas utilizing market forces are necessary to stimulate new investment efforts. Employing the benefits of both the previously described Advanced Market Commitment and a refined Call Options for Vaccines model, we describe herein a novel incentive mechanism, the Options Market for Antibiotics. RESULTS: This model applies the benefits of a financial call option to the investment in and purchase of new antibiotics. The goal of this new model is to provide an effective mechanism for early investment and risk sharing while maintaining a credible purchase commitment and incentives for companies to ultimately bring new antibiotics to market. CONCLUSIONS: We believe that the Options Market for Antibiotics (OMA) may help to overcome some of the traditional market failures associated with the development of new antibiotics. Additional work must be done to develop a more robust mathematical model to pave the way for practical implementation.