Clinical Practice Guidelines to Support Capacity Building in Orthopaedic Surgical Outreach: An International Consensus Building Approach

BACKGROUND

Surgical outreach to low- and middle-income countries (LMICs) by organizations from high- income countries is on the rise to help address the growing burden of conditions warranting surgery. However, concerns remain about the impact and sustainability of such outreach. Leading organizations (e.g., the World Health Organization) advocate for a capacity-building approach to ensure the safety, quality, and sustainability of the local health-care system. Despite this, to our knowledge, no guidelines exist to inform such efforts. We aimed to develop clinical practice guidelines (CPGs) to support capacity-building in orthopaedic surgical outreach utilizing a multistakeholder and international voting panel.

METHODS

We followed a modified American Academy of Orthopaedic Surgeons (AAOS) CPG development process. We systematically reviewed the existing literature across 7 predefined capacity-building domains (partnership, professional development, governance, community impact, finance, coordination, and culture). A writing panel composed of 6 orthopaedic surgeons with extensive experience in surgical outreach reviewed the existing literature and developed a consensus-based CPG for each domain. We created an international voting panel of orthopaedic surgeons and administrators who have leadership roles in outreach organizations or hospitals with which outreach organizations partner. Members individually reviewed the CPGs and voted to approve or disapprove each guideline. A CPG was considered approved if >80% of panel members voted to approve it.

RESULTS

An international voting panel of 14 surgeons and administrators from 6 countries approved all 7 of the CPGs. Each CPG provides recommendations for capacity-building in a specific domain. For example, in the domain of partnership, the CPG recommends the development of a documented plan for ongoing, bidirectional partnership between the outreach organization and the local team. In the domain of professional development, the CPG recommends the development of a needs-based curriculum focused on both surgical and nonsurgical patient care utilizing didactic and hands-on techniques.

CONCLUSIONS

As orthopaedic surgical outreach grows, best-practice CPGs to inform capacity-building initiatives can help to ensure that resources and efforts are optimized to support the sustainability of care delivery at local sites. These guidelines can be reviewed and updated in the future as evidence that supports capacity-building in LMICs evolves.The global burden of disease warranting surgery is substantial, and morbidity and mortality from otherwise treatable conditions remain disproportionately high in low- and middle-income countries (LMICs)1,2. It is estimated that up to 2 million (about 40%) of injury-related deaths in LMICs could be avoided annually if mortality rates were reduced to the level of those in high-income countries (HICs)3. Despite this, progress toward improved access to safe, timely surgery in resource-poor areas has been slow. Historically, nongovernmental organizations (NGOs) have tried to address unmet surgical needs through short-term outreach trips; however, growing criticism has highlighted the limitations of short-term trips, including limited follow-up, an increased burden on the local workforce, and further depletion of local resources4-6. In light of ongoing concerns, public health priorities have shifted toward models that emphasize long-term capacity-building rather than short-term care delivery. Capacity-building is an approach to health-care development that builds independence through infrastructure development, sustainability, and enhanced problem-solving while taking context into account7,8.

Current Treatment Landscape for Dystrophic Epidermolysis Bullosa: From Surgical Management to Emerging Gene Therapies and Novel Skin Grafts

Epidermolysis bullosa is a genetic skin disorder characterized by blister formation from mechanical trauma. Dystrophic epidermolysis bullosa (DEB) is caused by mutations in the COL7A1 gene presenting as generalized blisters from birth, which can result in extensive scarring, alopecia, esophageal stenosis, corneal erosions, and nail dystrophy. This disease also often leads to pseudosyndactyly of the digits from the closure of webspaces, progressing to a "mitten hand" deformity. Although traditional and current treatment for DEB is largely supportive with wound care and iterative surgical pseudosyndactyly release, emerging gene therapies and novel skin grafts may offer promising treatment. Studies published in the early 2020s have used HSV-1 vectors expressing missing COL7A1 genes to restore collagen function. One of these treatments, B-VEC, is an HSV-1-based topical gene therapy designed to restore collagen 7 by delivering the COL7A1 gene, leveraging a differentiated HSV-1 vector platform that evades the patient's immune system response. Other work has been performed to retrovirally modify autologous keratinocytes, but limitations of this process include increased labor in harvesting and engineering autologous cells. This article provides an overview of DEB treatment with an emphasis on emerging gene therapies and novel skin grafts, especially as they pertain to pseudosyndactyly treatment.

A New Model of Global Reconstructive Surgery Training With Reduced Carbon Footprint of Outreach

This economic evaluation compares carbon dioxide emissions from air transportation for surgical mission trips vs team training trips.

Successful topical treatment of human biofilms using multiple antibiotic elution from a collagen-rich hydrogel

Chronic non-healing wounds significantly strain modern healthcare systems, affecting 1-2% of the population in developed countries with costs ranging between $28.1 and $96.8 billion annually. Additionally, it has been established that chronic wounds resulting from comorbidities, such as peripheral vascular disease and diabetes mellitus, tend to be polymicrobial in nature. Treatment of polymicrobial chronic wounds with oral and IV antibiotics can result in antimicrobial resistance, leading to more difficult-to-treat wounds. Ideally, chronic ulcers would be topically treated with antibiotic combinations tailored to the microbiome of a patient's wound. We have previously shown that a topical collagen-rich hydrogel (cHG) can elute single antibiotics to inhibit bacterial growth in a manner that is nontoxic to mammalian cells. Here, we analyzed the microbiology of cultures taken from human patients diagnosed with diabetes mellitus suffering from chronic wounds present for more than 6 weeks. Additionally, we examined the safety of the elution of multiple antibiotics from collagen-rich hydrogel in mammalian cells in vivo. Finally, we aimed to create tailored combinations of antibiotics impregnated into cHG to successfully target and treat infections and eradicate biofilms cultured from human chronic diabetic wound tissue. We found that the majority of human chronic wounds in our study were polymicrobial in nature. The elution of multiple antibiotics from cHG was well-tolerated in mammalian cells, making it a potential topical treatment of the polymicrobial chronic wound. Finally, combinations of antibiotics tailored to each patient's microbiome eluted from a collagen-rich hydrogel successfully treated bacterial cultures isolated from patient samples via an in vitro assay.

Greening Hand Surgery: Targeted Measures to Reduce Waste in Ambulatory Trigger Finger and Carpal Tunnel Decompression

BACKGROUND

Operating rooms (ORs) produce approximately 70% of hospital waste. Greening strategies in the OR aim to reduce the environmental impact of surgery while maintaining patient safety and outcomes. The aim of this study was to strategically reduce waste and cost associated with common ambulatory hand procedures by implementing a 3-stage "green case" plan over a 1-year period in a high-volume tertiary referral hand surgery division.

METHODS

A 3-stage greening initiative for hand surgery was designed and implemented in ambulatory open carpal tunnel release (CTR) and trigger finger release (TFR) cases, including: (1) introduction of minor field sterility; (2) implementation of a lean and green minor hand surgery pack and reduced instrument set; and (3) elimination of gown use by surgeons and OR staff. Surgical supply usage and costs were tracked during the study period and compared with control.

RESULTS

Each "green case" resulted in savings of $105 compared with the control cases from the preceding year, excluding cost savings associated with reduced waste processing. There was a 64% and 75% reduction in waste and costs after greening, respectively. This equates to a minimum institutional annual savings of $51 000 when used for CTR and TFR. There was no observed increase in surgical site infections or complications after the introduction of greening.

CONCLUSION

Greening initiatives can be successfully implemented by surgeons to reduce waste and costs. With targeted greening of CTR and TFR procedures, we significantly reduced waste and decreased costs while maintaining patient safety and outcomes.

The Development and Validation of Data Elements and Process Steps for an Electronic Health Record for Hand Surgery Outreach Trips

Background  The surgical burden in low- and middle-income countries (LMICs) as reported by the number of surgical cases per capita is great. To improve global health and help address this burden, there has been a rise in surgical outreach to LMICs. In high-income countries, an electronic health record (EHR) is used to document and communicate data critical to the quality of care and patient safety. Despite this, there is little guidance or precedence on the data elements or processes for utilizing an EHR on outreach trips. We validated data elements and process steps for utilizing an EHR for hand surgery outreach trips. Methods  We conducted a literature review to identify data elements collected during surgical outreach trips. A future-state process map for the collection and documentation of data elements within an EHR was developed through literature review and semistructured interviews with experts in global outreach. An expert consortium completed a modified RAND/University of California at Los Angeles Delphi process to evaluate the importance and feasibility of each data element and process step. Results  In total, 65 data elements (e.g., date of birth) and 24 process steps (e.g., surgical site marking) were validated for use in an EHR for hand surgery outreach trips to LMICs. Conclusion  This validated portfolio of data elements/process steps can serve as the foundation for pilot testing of an EHR to document and communicate critical patient data on hand surgery outreach trips. Utilization of an EHR during outreach trips to LMICs may serve to improve the safety and quality of care provided. The validated data elements/process steps can serve as a guide for EHR development and implementation of other surgical specialties.

Capacity Assessment Tool to Promote Capacity Building in Global Orthopaedic Surgical Outreach

BACKGROUND

A growing number of nongovernmental organizations from high-income countries aim to provide surgical outreach for patients in low- and middle-income countries in a manner that builds capacity. There remains, however, a paucity of measurable steps to benchmark and evaluate capacity-building efforts. Based on a framework for capacity building, the present study aimed to develop a Capacity Assessment Tool for orthopaedic surgery (CAT-os) that could be utilized to evaluate and promote capacity building.

METHODS

To develop the CAT-os tool, we utilized methodological triangulation-an approach that incorporates multiple different types of data. We utilized (1) the results of a systematic review of capacity-building best practices in surgical outreach, (2) the HEALTHQUAL National Organizational Assessment Tool, and (3) 20 semistructured interviews to develop a draft of the CAT-os. We subsequently iteratively used a modified nominal group technique with a consortium of 8 globally experienced surgeons to build consensus, which was followed by validation through member-checking.

RESULTS

The CAT-os was developed and validated as a formal instrument with actionable steps in each of 7 domains of capacity building. Each domain includes items that are scaled for scoring. For example, in the domain of partnership, items range from no formalized plans for sustainable, bidirectional relationships (no capacity) to local surgeons and other health-care workers independently participating in annual meetings of surgical professional societies and independently creating partnership with third party organizations (optimal capacity).

CONCLUSIONS

The CAT-os details steps to assess capacity of a local facility, guide capacity-improvement efforts during surgical outreach, and measure the impact of capacity-building efforts. Capacity building is a frequently cited and commendable approach to surgical outreach, and this tool provides objective measurement to aid in improving the capacity in low and middle-income countries through surgical outreach.

Bard Versus the 2022 American Society of Plastic Surgeons In-Service Examination: Performance on the Examination in Its Intern Year

Background

Bard is a conversational generative artificial intelligence (AI) platform released by Google (Mountain View, CA) to the public in May 2023.

Objectives

This study investigates the performance of Bard on the American Society of Plastic Surgeons (ASPS) In-Service Examination to compare it to residents' performance nationally. We hypothesized that Bard would perform best on the comprehensive and core surgical principles portions of the examination.

Methods

Google's 2023 Bard was used to answer questions from the 2022 ASPS In-Service Examination. Each question was asked as written with the stem and multiple-choice options. The 2022 ASPS Norm Table was utilized to compare Bard's performance to that of subgroups of plastic surgery residents.

Results

A total of 231 questions were included. Bard answered 143 questions correctly corresponding to an accuracy of 62%. The highest-performing section was the comprehensive portion (73%). When compared with integrated residents nationally, Bard scored in the 74th percentile for post-graduate year (PGY)-1, 34th percentile for PGY-2, 20th percentile for PGY-3, 8th percentile for PGY-4, 1st percentile for PGY-5, and 2nd percentile for PGY-6.

Conclusions

Bard outperformed more than half of the first-year integrated residents (74th percentile). Its best sections were the comprehensive and core surgical principle portions of the examination. Further analysis of the chatbot's incorrect questions might help improve the overall quality of the examination's questions.

Scoping Review of Hydrogel Therapies in the Treatment of Diabetic Chronic Wounds

Chronic diabetic wounds are a significant issue that can be treated with topical hydrogel therapies. The aim of this study was to review the different compositions of hydrogel that have been developed and analyze their clinical relevance in the treatment of chronic diabetic wounds.

Methods

We conducted a scoping review in which twelve articles were selected for review after applying relevant inclusion and exclusion criteria using a two-reviewer strategy. Data extracted from these studies was used to answer the following research question: What is the composition of hydrogels used to treat chronic diabetic wounds and how effective are they?

Results

We analyzed five randomized controlled trials, two retrospective studies, three reviews, and two case reports. Hydrogel compositions discussed included mesenchymal stem cell sheets, carbomer, collagen, and alginate hydrogels, as well as hydrogels embedded with platelet-derived growth factor. Synthetic hydrogels, largely composed of carbomers, were found to have high levels of evidence supporting their wound healing properties, though few articles described their routine use in a clinical setting. Collagen hydrogels dominate the present-day hydrogel market in the clinical treatment of chronic diabetic wounds. The augmentation of hydrogels with therapeutic biomaterials is a new field of hydrogel research, with studies demonstrating promising early in vitro and in vivo animal studies demonstrating promising early results for in vitro and in vivo animal investigations.

Conclusions

Current research supports hydrogels as a promising topical therapy in the treatment of chronic diabetic wounds. Augmenting Food & Drug Administration-approved hydrogels with therapeutic substances remains an interesting early area of investigation.

Tenolysis and Salvage Procedures

Complications in flexor tendon repair are common and include tendon rupture, adhesion formation, and joint contracture. Risk factors include preexisting conditions, gross contamination, concurrent fracture, early unplanned loading of the repaired tendon, premature cessation of splinting, and aggressive early active range of motion protocols with insufficient repair strength. Rupture of a repaired tendon should be followed by early operative exploration, debridement, and revision with a four-core strand suture and nonbraided epitendinous suture. Wide-awake flexor tenolysis should be considered when adhesion formation results in the plateaued range of motion, and passive motion exceeds active motion. Two-staged reconstruction is recommended when injury results in excessive scaring, joint contracture, or an incompetent pulley apparatus.

Management of Brachial Plexus Birth Palsies: The Stanford Experience

The start of Stanford's brachial plexus birth palsy (BPBP) experience dates back to 1983, when Dr. Vincent Rod Hentz visited Dr. Alain Gilbert on sabbatical. Since then, our principles of care for patients with BPBP have evolved based on our group's longitudinal experience caring for children with the entire spectrum of sequelae that arise in children with BPBP. We base our clinical decision making on frequent serial examinations and use intraoperative evoked potentials to guide surgical decisions. Here, we discuss our current principles on surgical indications, timing of surgery, and preferred techniques for secondary surgery in patients with BPBP.

Long-term Outcomes following Operative Management of Pediatric Scapholunate Ligament Injuries

Background  Scapholunate (SL) ligament injuries are rarely diagnosed in children. This study reports the outcomes of surgically treated SL ligament injuries in patients younger than 18 years. Methods  A retrospective review was performed on 20 pediatric patients with SL ligament injuries. Records were reviewed for preoperative and postoperative radiographic data, intraoperative findings, classifications of interosseous ligament injury, and postoperative course. Results  Thirteen girls and seven boys sustained SL injuries requiring operative intervention and were followed for an average of 26 months. Magnetic resonance imaging (MRI) was performed in 15 patients, which revealed an SL tear in 7 patients. Arthroscopically, SL injuries were classified as Geissler grade III in 12 patients and grade IV in 5 patients. Based on the Mayo Wrist Score, nine patients had excellent or good results, while six demonstrated fair results. The mean wrist flexion-extension arc was 109 degrees, while the mean grip strength was 82% of the unaffected side. Patients treated >1 year following injury had significantly decreased grip strength and Mayo Wrist Score. Conclusion  In this study, worse results were seen in children with a protracted course prior to treatment of an SL injury. A high index of suspicion is necessary to detect an SL injury in the younger age group and should be in the differential for those with persistent dorsal wrist pain, tenderness over the dorsal SL joint, and/or positive Watson's test. MRI may assist in diagnosis but is not definitive to rule out injury. Arthroscopy is valuable to determine the extent of injury.

A Framework and Blueprint for Building Capacity in Global Orthopaedic Surgical Outreach

BACKGROUND

Nongovernmental organizations (NGOs) from high-income countries provide surgical outreach for patients in low and middle-income countries (LMICs); however, these efforts lack a coordinated measurement of their ability to build capacity. While the World Health Organization and others recommend outreach trips that aim to build the capacity of the local health-care system, no guidance exists on how to accomplish this. The objective of this paper is to establish a framework and a blueprint to guide the operations of NGOs that provide outreach to build orthopaedic surgical capacity in LMICs.

METHODS

We conducted a qualitative analysis of semistructured interviews with 16 orthopaedic surgeons and administrators located in 7 countries (6 LMICs) on the necessary domains for capacity-building; the analysis was guided by a literature review of capacity-building frameworks. We subsequently conducted a modified nominal group technique with a consortium of 10 U.S.-based surgeons with expertise in global surgical outreach, which was member-checked with 8 new stakeholders from 4 LMICs.

RESULTS

A framework with 7 domains for capacity-building in global surgical outreach was identified. The domains included professional development, finance, partnerships, governance, community impact, culture, and coordination. These domains were tiered in a hierarchical system to stratify the level of capacity for each domain. A blueprint was developed to guide the operations of an organization seeking to build capacity.

CONCLUSIONS

The developed framework identified 7 domains to address when building capacity during global orthopaedic surgical outreach. The framework and its tiered system can be used to assess capacity and guide capacity-building efforts in LMICs. The developed blueprint can inform the operations of NGOs toward activities that focus on building capacity in order to ensure a measured and sustained impact.

Assessment of a Synergistic Effect of Platelet-Rich Plasma and Stem Cell-Seeded Hydrogel for Healing of Rat Chronic Rotator Cuff Injuries

Outcomes after repair of chronic rotator cuff injuries remain suboptimal. Type-1 collagen-rich tendon hydrogel was previously reported to improve healing in a rat chronic rotator cuff injury model. Stem cell seeding of the tendon hydrogel improved bone quality in the same model. This study aimed to examine whether there was a synergistic and dose-dependent effect of platelet-rich plasma (PRP) on tendon-bone interface healing by combining PRP with stem cell-seeded tendon hydrogel. Human cadaveric tendons were processed into a hydrogel. PRP was prepared at two different platelet concentrations: an initial concentration (initial PRP group) and a higher concentration (concentrated PRP group). Tendon hydrogel was mixed with adipose-derived stem cells and one of the platelet concentrations. Methylcellulose, as opposed to saline, was used as a negative control due to comparable viscosity. The supraspinatus tendon was detached bilaterally in 33 Sprague-Dawley rats (66 shoulders). Eight weeks later, each detached tendon was repaired, and a hydrogel mixture or control was injected at the repair site. Eight weeks after repair, shoulder samples were harvested and assigned for biomechanical testing (n = 42 shoulders) or a combination of bone morphological and histological assessment (n = 24 shoulders). Biomechanical testing showed significantly higher failure load and stiffness in the concentrated PRP group than in control. Yield load in the initial and concentrated PRP groups were significantly higher than that in the control. There were no statistically significant differences between the initial and concentrated PRP groups. The addition of the highly concentrated PRP to stem cells-seeded tendon hydrogel improved healing biomechanically after chronic rotator cuff injury in rats compared to control. However, synergistic and dose-dependent effects were not seen.

Barriers and Facilitators of Outcome Collection During Hand Surgery Outreach: A Quality Improvement Study

BACKGROUND

Surgical outreach trips to low- and middle-income countries have been increasing. Outcome collection on these trips, however, has been inconsistent and often incomplete. We conducted a qualitative study of surgeons, administrators, and patients to identify the barriers and facilitators to outcome collection on hand surgery outreach trips to Hospital 175 in Ho Chi Minh City, Vietnam.

METHODS

A purposive sample of surgeons, administrators, and patients from Hospital 175 were interviewed about their beliefs regarding outcome collection. We used a semi-structured interview guide based on the Theoretical Domains Framework to systematically explore barriers and facilitators. Interviews were recorded, transcribed, and analyzed using content analysis. Beliefs underlying similar responses were identified and aggregated to describe barriers and facilitators of outcome measurement.

RESULTS

Twelve surgeons and administrative staff (3 visiting and 9 local) and 5 patients were interviewed before saturation was achieved. All stakeholders believed outcome collection on hand surgery outreach trips is important. Barriers identified were primarily related to environmental context and resources (eg, cost of returning) and memory, attention, and decision process (eg, difficulty in remembering patient follow-up intervals). The most commonly identified barriers address the distance patients live from the hospital/clinic, the resources required for them to return, and the lack of an organized system to assist in follow-up.

CONCLUSIONS

Multiple barriers to outcome collection exist at Hospital 175 in Vietnam. Understanding these barriers informs context-specific implementation approaches to collect outcomes on hand surgery outreach trips, which may improve the safety and quality of care provided.

Biomechanical, Histologic, and Micro-Computed Tomography Characterization of Partial-Width Full-Thickness Supraspinatus Tendon Injury in Rats

PURPOSE

Partial rotator cuff tears can cause shoulder pain and dysfunction and are more common than complete tears. However, few studies examine partial injuries in small animals and, therefore a robust, clinically relevant model may be lacking. This study aimed to fully characterize the established rat model of partial rotator cuff injury over time and determine if it models human partial rotator cuff tears.

METHODS

We created a full-thickness, partial-width injury at the supraspinatus tendon-bone interface bilaterally in 31 Sprague-Dawley rats. Rats were euthanized immediately, and at 2-, 3-, 4-, and 8-weeks after surgery. Fourteen intact shoulders were used as controls. Samples were assessed biomechanically, histologically, and morphologically.

RESULTS

Biomechanically, load to failure in controls and 8 weeks after injury was significantly greater than immediately and 3 weeks after injury. Load to failure at 8 weeks was comparable to control. However, the locations of failure were different between intact shoulders and partially injured samples. Bone mineral density at 8 weeks was significantly greater than that at 2 and 3 weeks. Although no animals demonstrated propagation to complete tear and the injury site remodeled histologically, the appearance at 8 weeks was not identical to that in the controls.

CONCLUSIONS

The biomechanical properties and bone quality decreased after the injury and was restored gradually over time with full restoration by 8 weeks after injury. However, the findings were not equivalent to the intact shoulder. This study demonstrated the limitations of the current model in its application to long-term outcome studies, and the need for better models that can be used to assess chronic partial rotator cuff injuries.

CLINICAL RELEVANCE

There is no small animal model that mimics human chronic partial rotator cuff tears, which limits our ability to improve care for this common condition.

Separating Fact From Fiction: A Nationwide Longitudinal Examination of Complex Regional Pain Syndrome Following Treatment of Dupuytren Contracture

BACKGROUND

One of the most feared complications following treatment of Dupuytren contracture is complex regional pain syndrome (CRPS). This study aims to provide a national perspective on the incidence of CRPS following treatment of Dupuytren contracture and identify patient factors to target for risk reduction.

METHODS

Using the Truven MarketScan databases from 2007 to 2016, individuals aged ≥18 years who developed CRPS within 1 year of treatment of Dupuytren contracture were identified using the International Classification of Disease diagnosis code for CRPS. Predictor variables included: age, sex, employment status, region, type of procedure, and concurrent carpal tunnel surgery. Multivariable logistic regression was used to analyze outcomes.

RESULTS

In all, 48 327 patients received treatment for Dupuytren contracture, including collagenase injection (13.6%); percutaneous palmar fasciotomy (10.3%); open palmar fasciotomy (3.9%); palmar fasciectomy with 0 (10.8%), 1 (29.2%), or multiple (19.6%) digit releases; or a combination of these procedures (12.8%). One hundred forty-five patients (0.31%) were diagnosed with CRPS at a mean of 3.4 months (standard deviation, 2.3) following treatment. Significant predictors of CRPS included female sex (odds ratio [OR], 2.02; P < .001), Southern region (OR, 1.80; P = .022), long-term disability status (OR, 4.73; P = .035), palmar fasciectomy with release of 1 (OR, 5.91; P = .003) or >1 digit (OR, 13.32; P < .001), or multiple concurrent procedures for Dupuytren contracture (OR, 8.23; P = .001).

CONCLUSIONS

Based on national commercial claims data, there is a lower incidence of CRPS following treatment of Dupuytren contracture than previously reported. Risk factors identified should help with preoperative counseling and assist clinicians in targeting risk reduction measures.

Short Message Service-Based Collection of Patient-Reported Outcome Measures on Hand Surgery Global Outreach Trips: A Pilot Feasibility Study

PURPOSE

As the burden of surgical care and the associated outreach trips to low- and middle-income countries increases, it is important to collect postoperative data to assess and improve the quality, safety, and efficacy of the care provided. In this pilot study, we aimed to evaluate the feasibility of short message service (SMS)-based mobile phone follow up to obtain patient-reported outcome measures after hand surgery during a surgical outreach trip to Vietnam.

METHODS

Patients undergoing surgery during a week-long outreach trip to Hospital 175 in Ho Chi Minh City, Vietnam, who owned a mobile phone, were included in this study. Eight eligible patients elected to participate and were sent an SMS-based, Health Insurance Portability and Accountability Act-compliant text message with a link to a contextualized shortened Disabilities of the Arm, Shoulder and Hand questionnaire at 1 day, 1 week, 2 weeks, 4 weeks, and 12 weeks after the surgery. The patient characteristics and instrument completion rates were reported.

RESULTS

The 8 patients had a mean age of 45.4 years and lived at a mean distance of 72.7 km from the hospital. Seven (87.5%), 7 (87.5%), 8 (100%), 6 (75%), and 8 (100%) patients completed the follow-up questionnaires at 1 day, 1 week, 2 weeks, 4 weeks, and 12 weeks after the surgery, respectively.

CONCLUSIONS

This pilot study demonstrates that the collection of patient-reported outcome measures after hand surgery outreach trips to low- and middle-income countries via SMS-based messaging is feasible for up to 12 weeks after the surgery.

CLINICAL RELEVANCE

Short message service-based messaging can be used to obtain postoperative outcome measures for up to 12 weeks after surgical outreach trips to low- and middle-income countries. This technology can be scaled and contextualized based on location to ensure that patient care during outreach trips is safe and effective.

Use of Tendon Allograft for Recurrent Extensor Carpi Ulnaris Instability in Ehlers-Danlos Syndrome: A Case Report

Background  Subluxation of the extensor carpi ulnaris (ECU) tendon can be a challenging problem to the surgeon, with no options described for failure following autologous reconstruction. It is our intention to provide guidance on technique by describing our experience in a 20-year-old male with Ehlers-Danlos syndrome. Case Description  The patient presented with pain and snapping of the ECU tendon, and failed both immobilization and ECU reconstruction with autologous extensor retinaculum. A gracilis tendon allograft was used to reconstruct the ECU sheath, in addition to ulnar groove deepening. At 1-year follow-up, the patient had no pain and the ECU was stable without recurrent subluxation. Literature Review  To the authors' knowledge, the use of tendon allograft for stabilization of recurrent ECU subluxation following surgical repair or reconstruction has not been previously described in the medical literature. Clinical Relevance  Utilization of tendon allograft is a viable technique to stabilize the ECU tendon while minimizing the risk in relying on compromised autologous tissue. This report represents the first account of successful reconstruction following failed autologous reconstruction.

Patient Willingness to Pay for Faster Return to Work or Smaller Incisions

Background: Value-based health care models such as bundled payments and accountable care organizations can penalize health systems and physicians for excess costs leading to low-value care. Health systems can minimize these extra costs by constraining diagnostic (eg, magnetic resonance imaging utilization) or treatment options with debatable necessity in the setting of clinical equipoise. Instead of restricting more expensive treatments, it is plausible that health systems could instead recoup the extra costs of these treatments by charging patients supplementary out-of-pocket charges (cost sharing). The primary aim of this exploratory study was to assess hand surgery patient willingness to pay supplementary out-of-pocket charges for a procedure that theoretically leads to an earlier return to work or smaller incisions when there are 2 procedures that lead to similar results (clinical equipoise). Methods: A total of 122 patients completed a questionnaire that included demographic information, a financial distress assessment, a series of scenarios asking patients the degree to which they are willing to pay extra for the procedure choice, as well as their perspective of how much insurers should be responsible for these additional costs. Results: Patients were willing to pay out-of-pocket to some degree for a procedure that leads to earlier return to work and smaller incision size when compared with a similar alternative procedure, but noted that insurers should bear a greater burden of costs. Approximately 10% of patients were willing to pay maximum amounts ($2500+) for earlier return to work (3, 7, and 14 days earlier) and smaller incision sizes of any length. Conclusions: Some patients may be willing to pay out-of-pocket and cost share for procedures that lead to earlier return to work and smaller incisions in the setting of clinical equipoise. As such, when developing and implementing alternative payment models, health systems could potentially offer services with debatable necessity in the setting of equipoise for a supplementary out-of-pocket charge.

Post-surgical wireless monitoring of arterial health progression

Early detection of limb ischemia, strokes, and heart attacks may be enabled via long-term monitoring of arterial health. Early stenosis, decreased blood flow, and clots are common after surgical vascular bypass or plaque removal from a diseased vessel and can lead to the above diseases. Continuous arterial monitoring for the early diagnosis of such complications is possible by implanting a sensor during surgery that is wirelessly monitored by patients after surgery. Here, we report the design of a wireless capacitive sensor wrapped around the artery during surgery for continuous post-operative monitoring of arterial health. The sensor responds to diverse artery sizes and extents of occlusion in vitro to at least 20 cm upstream and downstream of the sensor. It demonstrated strong capability to monitor progression of arterial occlusion in human cadaver and small animal models. This technology is promising for wireless monitoring of arterial health for pre-symptomatic disease detection and prevention.

Homing of Adipose-Derived Stem Cells to a Tendon-Derived Hydrogel: A Potential Mechanism for Improved Tendon-Bone Interface and Tendon Healing

PURPOSE

Tendons are difficult to heal owing to their hypocellularity and hypovascularity. Our laboratory has developed a tendon-derived hydrogel (tHG) that significantly improves tendon healing in an animal model. We hypothesized that a potential mechanism for improved healing with tHG is through the attraction of systemic stem cells.

METHODS

Homing of systemic adipose-derived stem cells (ADSCs) to tendon injuries was assessed with acute and chronic injury models. Injury sites were treated with saline or tHG, and animals given a tail vein injection (TVI) of labeled ADSCs 1 week after treatment. One week following TVI, rats were harvested for histology. To further evaluate a potential difference in homing to tHG, a subcutaneous injection (SQI) model was used. Rats were treated with an SQI of saline, silicone, ADSCs in media, tHG, tHG + fibroblasts (FBs), or tHG + ADSCs on day 0. One week after SQI, rats underwent TVI with labeled ADSCs. Samples were harvested 2 or 3 weeks after SQI for analysis. Flow cytometry confirmed homing in the SQI model.

RESULTS

Systemically delivered ADSCs homed to both acute tendon and chronic tendon-bone interface (TBI) injury sites. Despite their presence at the injury site, there was no difference in the number of macrophages, amount of cell proliferation, or angiogenesis 1 week after stem cell delivery. In an SQI model, ADSCs homed to tHG. There was no difference in the number of ADSCs homing to tHG alone versus tHG + ADSCs. However, there was an increase in the number of living cells, general immune cells, and T-cells present at tHG + ADSC versus tHG alone.

CONCLUSIONS

The ADSCs home to tendon injury sites and tHG. We believe the attraction of additional systemic ADSCs is one mechanism for improved tendon and TBI healing with tHG.

CLINICAL RELEVANCE

Treatment of tendon and TBI injuries with tHG can augment healing via homing of systemic stem cells.

Topical Antibiotic Elution in a Collagen-Rich Hydrogel Successfully Inhibits Bacterial Growth and Biofilm Formation In Vitro

Chronic wounds are a prominent concern, accounting for $25 billion of health care costs annually. Biofilms have been implicated in delayed wound closure, but they are susceptible to developing antibiotic resistance and treatment options continue to be limited. A novel collagen-rich hydrogel derived from human extracellular matrix presents an avenue for treating chronic wounds by providing appropriate extracellular proteins for healing and promoting neovascularization. Using the hydrogel as a delivery system for localized secretion of a therapeutic dosage of antibiotics presents an attractive means of maximizing delivery while minimizing systemic side effects. We hypothesize that the hydrogel can provide controlled elution of antibiotics leading to inhibition of bacterial growth and disruption of biofilm formation. The rate of antibiotic elution from the collagen-rich hydrogel and the efficacy of biofilm disruption was assessed with Pseudomonas aeruginosa Bacterial growth inhibition, biofilm disruption, and mammalian cell cytotoxicity were quantified using in vitro models. The antibiotic-loaded hydrogel showed sustained release of antibiotics for up to 24 h at therapeutic levels. The treatment inhibited bacterial growth and disrupted biofilm formation at multiple time points. The hydrogel was capable of accommodating various classes of antibiotics and did not result in cytotoxicity in mammalian fibroblasts or adipose stem cells. The antibiotic-loaded collagen-rich hydrogel is capable of controlled antibiotic release effective for bacteria cell death without native cell death. A human-derived hydrogel that is capable of eluting therapeutic levels of antibiotic is an exciting prospect in the field of chronic wound healing.

Neonatal Compartment Syndrome and Compound Presentation at Birth

Neonatal compartment syndrome is a rare condition. Early diagnosis and timely surgical intervention are paramount to optimize outcome. Time to fasciotomy is the most important prognostic factor. The purposes of this study were to describe a case presentation of neonatal compartment syndrome associated with a compound birth presentation and to perform a literature review. In this case, the neonate’s fingers were noted to be present on maternal cervical examination 24 hours before delivery. The patient then was noted to have a sentinel skin lesion. A diagnosis of neonatal compartment syndrome was suspected, and she underwent urgent fasciotomy. Literature review identified a total of 60 patients from 26 studies. Most patients were managed operatively. All patients presented with a sentinel skin lesion, emphasizing the importance of this clinical sign in diagnosis. Manometry is not routinely performed and no standards are available for acceptable pressure gradients.

Electromyographic Analysis of Grip

This prospective cohort study used video electromyography synchronized analysis to determine the dynamic use of extrinsic and intrinsic finger flexion during grasp. Light fist formation primarily involved the flexor digitorum profundus with either the flexor digitorum superficialis or intrinsics. In contrast, both the flexor digitorum superficialis and intrinsics were recruited in all tight fist video electromyography. However, the sequence of recruitment differed between patients in tight fist formation. Injured patients demonstrated a unique pattern of recruitment based on injury. The authors conclude that the flexor digitorum profundus is the workhorse in composite fist formation but the roles of the flexor digitorum superficialis and the intrinsic muscles are less consistent across patients. [Orthopedics. 2019; 42(6):e555-e558.].

A Novel Technology for Free Flap Monitoring: Pilot Study of a Wireless, Biodegradable Sensor

BACKGROUND

 Accurate monitoring of free flap perfusion after complex reconstruction is critical for early recognition of flap compromise. Surgeons use a variety of subjective and objective measures to evaluate flap perfusion postoperatively. However, these measures have some limitations. We have developed a wireless, biodegradable, and flexible sensor that can be applied to real-time postoperative free flap monitoring. Here we assess the biocompatibility and function of our novel sensor.

METHODS

 Seven Sprague-Dawley (SD) rats were used for biocompatibility studies. The sensor was implanted around the femoral artery near the inguinal ligament on one leg (implant side) and sham surgery was performed on the contralateral leg (control side). At 6 and 12 weeks, samples were harvested to assess the inflammation within and around the implant and artery. Two animals were used to assess sensor function. Sensor function was evaluated at implantation and 7 days after the implantation. Signal changes after venous occlusion were also assessed in an epigastric artery island flap model.

RESULTS

 In biocompatibility studies, the diameter of the arterial lumen and intima thickness in the implant group were not significantly different than the control group at the 12-week time point. The number of CD-68 positive cells that infiltrated into the soft tissue, surrounding the femoral artery, was also not significantly different between groups at the 12-week time point. For sensor function, accurate signaling could be recorded at implantation and 7 days later. A change in arterial signal was noted immediately after venous occlusion in a flap model.

CONCLUSION

 The novel wireless, biodegradable sensor presented here is biocompatible and capable of detecting arterial blood flow and venous occlusion with high sensitivity. This promising new technology could combat the complications of wired sensors, while improving the survival rate of flaps with vessel compromise due to its responsive nature.

Human Tendon-Derived Collagen Hydrogel Significantly Improves Biomechanical Properties of the Tendon-Bone Interface in a Chronic Rotator Cuff Injury Model

PURPOSE

Poor healing of the tendon-bone interface (TBI) after rotator cuff (RTC) tears leads to high rates of recurrent tear following repair. Previously, we demonstrated that an injectable, thermoresponsive, type I collagen-rich, decellularized human tendon-derived hydrogel (tHG) improved healing in an acute rat Achilles tendon injury model. The purpose of this study was to investigate whether tHG enhances the biomechanical properties of the regenerated TBI in a rat model of chronic RTC injury and repair.

METHODS

Tendon hydrogel was prepared from chemically decellularized human cadaveric flexor tendons. Eight weeks after bilateral resection of supraspinatus tendons, repair of both shoulders was performed. One shoulder was treated with a transosseous suture (control group) and the other was treated with a transosseous suture plus tHG injection at the repair site (tHG group). Eight weeks after repair, the TBIs were evaluated biomechanically, histologically, and via micro-computed tomography (CT).

RESULTS

Biomechanical testing revealed a larger load to failure, higher stiffness, higher energy to failure, larger strain at failure, and higher toughness in the tHG group versus control. The area of new cartilage formation was significantly larger in the tHG group. Micro-CT revealed no significant difference between groups in bone morphometry at the supraspinatus tendon insertion, although the tHG group was superior to the control.

CONCLUSIONS

Injection of tHG at the RTC repair site enhanced biomechanical properties and increased fibrocartilage formation at the TBI in a chronic injury model.

CLINICAL RELEVANCE

Treatment of chronic RTC injuries with tHG at the time of surgical treatment may improve outcomes after surgical repair.

Localised grey matter atrophy in multiple sclerosis is network-based: a coordinate-based meta-analysis

AIM

To test the network degeneration hypothesis in multiple sclerosis (MS) with a two-stage coordinate-based meta-analysis by: (1) characterising regional selectivity of grey matter (GM) atrophy and (2) testing for functional connectivity involving these regions.

MATERIALS AND METHODS

Meta-analytic sources included 33 journal articles (1,666 MS patients and 1,269 healthy controls) with coordinate-based results from voxel-based morphometry analysis demonstrating GM atrophy. Mass univariate and multivariate coordinate-based meta-analyses were performed to identify a convergent pattern of GM atrophy and determine inter-regional co-activation (as a surrogate of functional connectivity), with anatomical likelihood estimation and functional meta-analytic connectivity modelling, respectively.

RESULTS

Localised GM atrophy was demonstrated in the thalamus, putamen, caudate, sensorimotor cortex, insula, superior temporal gyrus, and cingulate gyrus. This convergent pattern of atrophy displayed significant inter-regional functional co-activations.

CONCLUSION

In MS, GM atrophy was regionally selective, and these regions were functionally connected. The meta-analytic model-based results of this study are intended to guide future development of quantitative neuroimaging markers for diagnosis, evaluating disease progression, and monitoring treatment response.

Augmentation of chronic rotator cuff healing using adipose-derived stem cell-seeded human tendon-derived hydrogel

Rotator cuff (RTC) repair outcomes are unsatisfactory due to the poor healing capacity of the tendon bone interface (TBI). In our preceding study, tendon hydrogel (tHG), which is a type I collagen rich gel derived from human tendons, improved biomechanical properties of the TBI in a rat chronic RTC injury model. Here we investigated whether adipose-derived stem cell (ASC)-seeded tHG injection at the repair site would further improve RTC healing. Rats underwent bilateral supraspinatus tendon detachment. Eight weeks later injured supraspinatus tendons were repaired with one of four treatments. In the control group, standard transosseous suture repair was performed. In the ASC, tHG, tHGASC groups, ASC in media, tHG, and ASC-seeded tHG were injected at repair site after transosseous suture repair, respectively. Eight weeks after repair, the TBI was evaluated biomechanically, histologically, and via micro CT. Implanted ASCs were detected in ASC and tHGASC groups 7 weeks after implantation. ACS implantation improved bone morphometry at the supraspinatus insertion on the humerus. Injection of tHG improved biomechanical properties of the repaired TBI. RTC healing in tHGASC group was significantly better than control but statistically equivalent to the tHG group based on biomechanical properties, fibrocartilage area at the TBI, and bone morphometry at the supraspinatus insertion. In a rat RTC chronic injury model, no biomechanical advantage was gained with ASC augmentation of tHG. Clinical Significance: Tendon hydrogel augmentation with adipose derived stem cells does not significantly improve TBI healing over tHG alone in a chronic rotator cuff injury model. © 2019 Orthopaedic Research Society. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Quality of surgical randomized controlled trials in hand surgery: a systematic review

We assessed the quantity, quality and trends of randomized controlled trials comparing hand surgical interventions. Study characteristics were collected for 125 randomized controlled trials comparing hand surgical interventions. The Jadad scale (0-5), which assesses methodological quality of trials, was calculated. Logistic regressions were conducted to determine associations with the Jadad score. The studies were published between 1981 and 2015, with an increase over time, most often in Journal of Hand Surgery (European). Mean study size was 68 patients. Mean Jadad score was 2.1, without improvement over time. Thirty percent conducted a power analysis and 8% an intention-to-treat analysis. Studies conducted in the United Kingdom and with smaller sample sizes, power analysis and intention-to-treat analysis were associated with a higher Jadad score. The quantity of trials has increased over time while methodological quality has remained low, indicating a need to improve quality of trials in hand surgery literature.

Treating the Proximal Interphalangeal Joint in Swan Neck and Boutonniere Deformities

Swan neck and boutonniere deformities of the proximal interphalangeal (PIP) joint are challenging to treat. In a swan neck deformity, the PIP joint is hyperextended with flexion at the distal interphalangeal (DIP) joint. In a boutonniere deformity, there is flexion the PIP joint with hyperextension of the DIP joint. When the deformities are flexible, treatment begins with splinting. However, when the deformity is fixed, serial casting or surgery is often necessary to restore joint motion before surgical correction. Many surgical techniques have been described to treat both conditions. Unfortunately, incomplete correction and deformity recurrence are common.

Molecular Biology of Flexor Tendon Healing in Relation to Reduction of Tendon Adhesions

Tendon injuries are encountered after major and minor hand trauma. Despite meticulous repair technique, adhesion formation can occur, limiting recovery. Although a great deal of progress has been made toward understanding the mechanism of tendon healing and adhesions, clinically applicable solutions to prevent adhesions remain elusive. The goal of this paper is to review the most recent literature relating to the tendon healing and adhesion prevention.

Access to surgical upper extremity care for people with tetraplegia: an international perspective

STUDY DESIGN

Survey.

OBJECTIVES

To determine whether upper extremity reconstruction in patients with tetraplegia is underutilized internationally and, if so, what are the barriers to care.

SETTING

International-attendees of a meeting in Paris, France.

METHODS

One hundred and seventy attendees at the Tetrahand meeting in Paris in 2010 were sent a 13-question survey to determine the access and utilization of upper limb reconstruction in tetraplegic patients in their practice.

RESULTS

Respondents ranged the globe including North America, South America, Europe, Asia and Australia. Fifty-nine percent of respondents had been practicing for more than 10 years. Sixty-four percent of respondents felt that at least 25% of people with tetraplegia would be candidates for surgery. Yet the majority of respondents found that <15% of potential patients underwent upper extremity reconstruction. Throughout the world direct patient referral was the main avenue of surgeons meeting patients with peer networking a distant second. Designated as the top three barriers to this care were lack of knowledge of surgical options by patients, lack of desire for surgery and poor referral patterns to appropriate upper extremity surgeons.

CONCLUSION

The results of this survey, of a worldwide audience, indicate that many of the same barriers to care exist regardless of the patient's address. This was a preliminary opinion survey and thus the results are subjective. However, these results provide a roadmap to improving access to care by improving patient education and interdisciplinary physician communication.

Decellularized human tendon-bone grafts for composite flexor tendon reconstruction: a cadaveric model of initial mechanical properties

PURPOSE

After complex hand trauma, restoration of tendon strength is challenging. Tendon insertion tears typically heal as fibrous scars after surgical reconstruction and create a weak point at the tendon-bone interface. In addition, major tendon loss may overwhelm the amount of available autograft for reconstruction. An off-the-shelf product may help address these challenges. We hypothesized that decellularized human flexor digitorum profundus and distal phalanx tendon-bone composite grafts were a feasible option for flexor tendon reconstruction after complex hand trauma. By replacing the entire injured composite segment, the need for tendon repair within the tendon sheath, reconstruction of the tendon-bone interface, and use of limited autograft could be eliminated.

METHODS

Paired human cadaver forearms were dissected to obtain the flexor digitorum profundus tendon with an attached block of distal phalanx. Tendon-bone grafts were pair-matched and divided into 2 groups: decellularized grafts (n = 12) and untreated (control) grafts (n = 11). Grafts in the decellularized group were subjected to physiochemical decellularization. Pair-matched tendon-bone grafts (decellularized and untreated) were placed back into the flexor tendon sheath and secured distally using a tie-over button and proximally by weaving the graft into the flexor digitorum superficialis tendon in the distal forearm. The ultimate load, location of failure, and excursion were determined.

RESULTS

Decellularized tendon-bone composite grafts demonstrated no significant difference in ultimate failure load or stiffness compared with untreated grafts. Both groups eventually failed in varied locations along the repair. The most common site of failure in both groups was the tie-over button. The decellularized group failed at the tendon-bone insertion in 3 specimens (25%) compared with none in the untreated group. Both groups demonstrated an average tendon excursion of approximately 82 mm before failure.

CONCLUSIONS

Decellularization of human flexor tendon-distal phalanx tendon-bone constructs did not compromise initial strength despite chemical and mechanical decellularization in a cadaveric model. At the time of repair, decellularized flexor tendon-bone grafts can exceed the strength and excursion needed for hand therapy immediately after reconstruction.

CLINICAL RELEVANCE

These tendon-bone grafts may become an option for complex hand reconstruction at or near tendon-bone insertions and throughout the tendon sheath. Further work is required to assess the role of reseeding in an in vivo model.

Computed tomography angiography in microsurgery: indications, clinical utility, and pitfalls

OBJECTIVE

Computed tomographic angiography (CTA) can be used to obtain 3-dimensional vascular images and soft-tissue definition. The goal of this study was to evaluate the reliability, usefulness, and pitfalls of CTA in preoperative planning of microvascular reconstructive surgery.

METHODS

A retrospective review of patients who obtained preoperative CTA in preparation for planned microvascular reconstruction was performed over a 5-year period (2001-2005). The influence of CTA on the original operative plan was assessed for each patient, and CTA results were correlated to the operative findings.

RESULTS

Computed tomographic angiography was performed on 94 patients in preparation for microvascular reconstruction. In 48 patients (51%), vascular abnormalities were noted on CTA. Intraoperative findings correlated with CTA results in 97% of cases. In 42 patients (45%), abnormal CTA findings influenced the original operative plan, such as the choice of vessels, side of harvest, or nature of the reconstruction (local flap instead of free tissue transfer). Technical difficulties in performing CTA were encountered in 5 patients (5%) in whom interference from external fixation devices was the main cause.

CONCLUSIONS

This large study of CTA obtained for preoperative planning of reconstructive microsurgery at both donor and recipient sites study demonstrates that CTA is safe and highly accurate. Computed tomographic angiography can alter the surgeon's reconstructive plan when abnormalities are noted preoperatively and consequently improve results by decreasing vascular complication rates. The use of CTA should be considered for cases of microsurgical reconstruction where the vascular anatomy may be questionable.

Tissue expander with acellular dermal matrix for breast reconstruction infected by an unusual pathogen: Candida parapsilosis

Infections occur in approximately 2-5% percent of women undergoing breast reconstruction by tissue expansion depending on patient characteristics and timing of reconstruction. Bacteria, specifically Staphylococci, are the most common pathogens. Treatment varies depending on the surgeon and the aggressiveness of the infection. We report a case of unilateral tissue expander infection with Candida parapsilosis in an otherwise healthy female undergoing immediate tissue expander placement after bilateral nipple-sparing mastectomies. The patient was treated with a one-stage irrigation, debridement, and tissue expander exchange as well as a 21-day course of oral antifungal therapy. Her infection resolved and she was able to complete her implant-based reconstruction. C. parapsilosis is usually responsible for infections in critically ill patients found in association with central lines, peritoneal dialysis catheters and prosthetic heart valves. The affinity of C. parapsilosis for foreign material makes it a causative agent worth considering in difficult to treat tissue expander infections.

Lack of relationship between purine biosynthesis and vancomycin resistance in Staphylococcus aureus: a cautionary tale for microarray interpretation

Previous microarray data (E. Mongodin, J. Finan, M. W. Climo, A. Rosato, S. Gill, and G. L. Archer, J. Bacteriol. 185:4638-4643, 2003) noted an association in two vancomycin-intermediate Staphylococcus aureus (VISA) strains between high-level, passage-induced vancomycin resistance, a marked increase in the transcription of purine biosynthetic genes, and mutation of the putative purine regulator purR. Initial studies to report on the possible association between vancomycin resistance and alterations in purine metabolism in one of these strains (VP-32) confirmed, by Western analysis, an increase in the translation of PurH and PurM, two purine pathway enzymes. In addition, PurR was identified, by knockout and complementation in a vancomycin-susceptible strain, as a repressor of the purine biosynthetic operon in S. aureus, and the PurR missense mutation was shown to inactivate the repressor. However, despite the apparent relationship between increased purine biosynthesis and increased vancomycin resistance in VP-32, neither the addition of exogenous purines to a defined growth medium nor the truncation or inactivation of purR improved the growth of vancomycin-susceptible S. aureus in the presence of vancomycin. Furthermore, the passage of additional vancomycin-susceptible and VISA strains to high-level vancomycin resistance occurred without changes in cellular purine metabolism or mutation of purR despite the development of thickened cell walls in passaged strains. Thus, we could confirm neither a role for altered purine metabolism in the development of vancomycin resistance nor its requirement for the maintenance of a thickened cell wall. The failure of biochemical and physiological studies to support the association between transcription and phenotype initially found in careful microarray studies emphasizes the importance of follow-up investigations to confirm microarray observations.

Successful therapy of experimental endocarditis caused by vancomycin-resistant Staphylococcus aureus with a combination of vancomycin and beta-lactam antibiotics

VRS1 is the first isolated strain of vancomycin-resistant Staphylococcus aureus (VRSA) found to carry the vanA gene complex previously described in Enterococcus. Under vancomycin pressure, VRS1 makes aberrant cell walls consisting of stem tetrapeptide and depsipeptide that lack the terminal D-Ala-D-Ala residues targeted by vancomycin. Previous data have suggested that this aberrant cell wall is not cross-linked by PBP2a, the enzyme responsible for cell wall transpeptidation in the presence of beta-lactam antibiotics. We examined the efficacy of treating VRS1 with a combination of vancomycin and beta-lactam antibiotics in vitro and in vivo. We found that the MIC of oxacillin for VRS1 decreased from >256 microg/ml to <1 microg/ml in the presence of vancomycin. Using the rabbit model of endocarditis, we treated VRS1-infected rabbits with nafcillin alone, vancomycin alone, or a combination of nafcillin and vancomycin. Treatment with nafcillin in combination with vancomycin cleared bloodstream infections within 24 h and sterilized 12/13 spleens (92%), as well as 8/13 kidneys (62%), following 3 days of treatment. Mean aortic valve vegetation counts were reduced 3.48 log(10) CFU/g with the combination therapy (compared to untreated controls) and were significantly lower than with either vancomycin or nafcillin given alone. VRS1 was extremely virulent in this model, as no untreated rabbits survived the 3-day trial. Treatment of clinical infections due to VRSA with the combination of vancomycin and beta-lactams may be an option, based on these results.

Vancomycin-intermediate Staphylococcus aureus strains have impaired acetate catabolism: implications for polysaccharide intercellular adhesin synthesis and autolysis

The most common mechanism by which Staphylococcus aureus gains resistance to vancomycin is by adapting its physiology and metabolism to permit growth in the presence of vancomycin. Several studies have examined the adaptive changes occurring during the transition to vancomycin-intermediate resistance, leading to a model of vancomycin resistance in which decreased cell wall turnover and autolysis result in increased cell wall thickness and resistance to vancomycin. In the present study, we identified metabolic changes common to vancomycin-intermediate S. aureus (VISA) strains by assessing the metabolic and growth characteristics of two VISA strains (vancomycin MICs of 8 microg/ml) and two isogenic derivative strains with vancomycin MICs of 32 microg/ml. Interestingly, we observed the parental strains had impaired catabolism of nonpreferred carbon sources (i.e., acetate), and this impairment became more pronounced as vancomycin resistance increased. To determine if acetate catabolism impairment is common to VISA strains, we assessed the ability of VISA and vancomycin-sensitive S. aureus (VSSA) clinical isolates to catabolize acetate. As expected, a significantly greater percentage of VISA strains (71%) had impaired acetate catabolism relative to VSSA (8%). This is an important observation because staphylococcal acetate catabolism is implicated in growth yield and antibiotic tolerance and in regulating cell death and polysaccharide intercellular adhesin synthesis.

The up-regulation of ferritin expression using a small-molecule ligand to the native mRNA

The binding of small molecules to distinctive three-dimensional structures in mRNA provides a new dimension in RNA control, previously limited to the targeting of secondary structures with antisense and RNA interference; such targeting can modulate mRNA function and rates of protein biosynthesis. Small molecules that selectively bind the iron-responsive element (IRE), a specific three-dimensional structure in the noncoding region of the ferritin mRNA model that is recognized by the iron-regulatory protein repressor, were identified by using chemical footprinting. The assay used involved an oxoruthenium(IV) complex that oxidizes guanine bases in RNA sequences. Small molecules that blocked oxidation of guanines in the internal loop region were expected to selectively increase the rate of ferritin synthesis, because the internal loop region of the ferritin IRE is distinctive from those of other IREs. The natural product yohimbine was found (based on gel mobility shifts) to block cleavage of the internal loop RNA site by >50% and seemed to inhibit protein binding. In the presence of yohimbine, the rate of biosynthesis of ferritin in a cell-free expression system (rabbit reticulocyte lysate) increased by 40%. Assignment of the IRE-yohimbine interaction as the origin of this effect was supported by a similar increase in synthesis of luciferase protein in a chimera of the IRE and luciferase gene. The identification of a small, drug-like molecule that recognizes a naturally occurring three-dimensional mRNA structure and regulates protein biosynthesis rates raises the possibility that small molecules can regulate protein biosynthesis by selectively binding to mRNA.

The mid genes of Rhizobium sp strain TAL1145 are required for degradation of mimosine into 3-hydroxy-4-pyridone and are inducible by mimosine

Mimosine is a toxin present in the tree-legume leucaena (Leucaena leucocephala), including its root nodules and the root exudates. The leucaena-nodulating Rhizobium sp. strain TAL1145 degrades mimosine (Mid(+)) and utilizes it as a source of carbon and nitrogen. Twelve TAL1145 mutants defective in mimosine degradation (Mid(-)) were made through Tn3Hogus, TnphoA or kanamycin-resistance-cassette insertions. A 5.0 kb PstI fragment of TAL1145, subcloned from a cosmid clone containing mid genes for mimosine degradation, complemented most of the Mid(-) mutants. Sequencing this fragment and the adjacent 0.9 kb PstI fragment identified five genes, midA, midB, midC, midD and midR, of which the first three genes encode ABC transporter proteins involved in mimosine uptake, while midD encodes an aminotransferase required for degrading mimosine into 3-hydroxy-4-pyridone, and midR is a regulatory gene encoding a LysR-type transcriptional activator. The location of MidA in the periplasm was shown by making two midA : : phoA fusions, which made active alkaline phosphatase in the periplasm. The various mid : : gus and midA : : phoA fusions were inducible by mimosine, and a midD : : gus fusion mutant showed beta-glucuronidase activity in the leucaena nodules, indicating that midD is expressed in the nodules. Similarly, a midA : : phoA fusion expressed alkaline phosphatase activity in the leucaena nodules, indicating that mimosine induces midA transcription in the bacteroids. mid genes are specific for the Mid(+) strains of leucaena Rhizobium and are absent in strains of other Rhizobium, Sinorhizobium and Bradyrhizobium spp.

Selection of several classes of mimosine-degradation-defective Tn3Hogus-insertion mutants of Rhizobium sp. strain TAL1145 on the basis of mimosine-inducible GUS activity

Rhizobium sp. strain TAL1145 that nodulates Leucaena leucocephala degrades mimosine, a toxin produced by this tree legume. A cosmid clone, pUHR263, containing ~25 kb cloned DNA was isolated by plating Escherichia coli cells containing the cosmid clone library of TAL1145 on a minimal medium in which 3-hydroxy-4-pyridone (HP), a degradation product of mimosine, was used as the source of nitrogen. Cosmid pUHR263 was mutagenized by random insertions of Tn3Hogus, a transposon that makes transcriptional gus fusions when it is inserted in a gene in the correct orientation. Various pUHR263::Tn3Hogus derivatives that showed mimosine-inducible or mimosine-repressible GUS activities when transferred to the Rhizobium sp. strain TAL1145 were selected. Mutants of TAL1145 were constructed by transferring these Tn3Hogus insertions into the TAL1145 chromosome through double-homologous recombination. These mutants were classified into five classes on the basis of defects in mimosine degradation. The growth of these mutants was inhibited to different extents by mimosine applied to the growth medium. Mimosine forms a red-colored Fe-mimosine complex when FeCl3 is added to the medium. The inhibitory effect of Fe-mimosine on growth of the mutants was much less than that of mimosine.Key words: mimosine, mid and pyd genes, Leucaena leucocephala, tree legume, Tn3Hogus.

Selection of several classes of mimosine-degradation-defective Tn3Hogus-insertion mutants of Rhizobium sp. strain TAL1145 on the basis of mimosine-inducible GUS activity

Rhizobium sp. strain TAL1145 that nodulates Leucaena leucocephala degrades mimosine, a toxin produced by this tree legume. A cosmid clone, pUHR263, containing approximately 25 kb cloned DNA was isolated by plating Escherichia coli cells containing the cosmid clone library of TAL1145 on a minimal medium in which 3-hydroxy-4-pyridone (HP), a degradation product of mimosine, was used as the source of nitrogen. Cosmid pUHR263 was mutagenized by random insertions of Tn3Hogus, a transposon that makes transcriptional gus fusions when it is inserted in a gene in the correct orientation. Various pUHR263::Tn3Hogus derivatives that showed mimosine-inducible or mimosine-repressible GUS activities when transferred to the Rhizobium sp. strain TAL1145 were selected. Mutants of TAL1145 were constructed by transferring these Tn3Hogus insertions into the TAL1145 chromosome through double-homologous recombination. These mutants were classified into five classes on the basis of defects in mimosine degradation. The growth of these mutants was inhibited to different extents by mimosine applied to the growth medium. Mimosine forms a red-colored Fe-mimosine complex when FeCI3 is added to the medium. The inhibitory effect of Fe-mimosine on growth of the mutants was much less than that of mimosine.