Flexor Tendon Injuries.

Flexor tendon injuries are complex, and management of these injuries requires consideration of the surgical timing, injury location, approach, and soft tissue handling. Complications are common, including adhesions, tendon rupture, infection, and a high reoperation rate for zone 2 repairs. Special considerations are given to chronic ruptures, concomitant fractures, and pediatric cases. We discuss current concepts that may improve patient outcomes.

Thinking Outside the Operating Room: Guidance on Designing a Safe and Effective Minor Procedure Room.

The minor procedure room (MPR) offers numerous advantages over the traditional operating room for performing many common hand surgeries. MPRs require less space, are subject to more practical architectural design standards, and facilitate more judicious use of disposable materials and unnecessary instruments than common hand surgeries. MPRs reduce costs to the system and patient at every step of the surgical workflow and improve efficiency by removing preoperative and postoperative monitoring requirements. Hand surgeons sometimes face resistance when attempting surgery in MPRs, often because of confusion about their design characteristics and capabilities. This article aims to clarify many of the major requirements for establishing an MPR and provide a guide to hand surgeons for performing safe, efficient surgery outside the operating room.

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.

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.

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.

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.

A Human-Derived, Collagen-Rich Hydrogel Augments Wound Healing in a Diabetic Animal Model.

BACKGROUND: Application of collagen products to wounds has been shown to improve wound healing. Using a collagen-based hydrogel (cHG) capable of cellular support previously developed by our laboratory, we hypothesize that our hydrogel will increase the speed of wound healing by providing a 3-dimensional framework for cellular support, increasing angiogenesis and cell-proliferation at the wound bed. METHODS: Two, 10-mm excisional wounds were created over the dorsum of 12 male, genetically modified Zucker diabetic rats. Wounds were splinted open to limit healing by wound contracture. One wound was treated with an occlusive dressing (OD), whereas the adjacent wound was treated with an OD plus cHG. Occlusive dressings were changed every other day. Hydrogel was applied on day 2 and every 4 days after until complete wound closure. Rate of wound closure was monitored with digital photography every other day. Wounds were harvested at days 10 and 16 for histological and immunohistochemical analysis. RESULTS: Wound closure was significantly faster in cHG-treated wounds compared with OD-treated wounds. By day 10, cHG-treated wounds achieved 63% wound closure, compared with 55% wound closure in OD-treated wounds (P < 0.05). By day 16, cHG-treated wounds achieved 84% wound closure, compared with 68% wound closure in OD-treated wounds (P < 0.05).Histologically, wound depth was not different between the cHG and OD groups on days 10 and 16. However, wound length was significantly less in the cHG group compared with the OD group (P < 0.05) consistent with digital photographic analysis. Immunohistochemical analysis for RECA-1 demonstrated that blood vessel density in the wound bed was 2.3 times higher in the cHG group compared with the OD group (P = 0.01) on day 16. Cell proliferation was 3.8 times higher in the cHG group versus the OD group (P < 0.05) on day 10. CONCLUSIONS: Collagen-based hydrogel-treated wounds demonstrated significantly improved healing compared with control. The thermoresponsive feature of collagen hydrogel and its structural stability at body temperature demonstrate promising clinical potential as a vehicle for the delivery of therapeutic cells to the wound bed.

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.

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.

Tendon Tissue Engineering: Mechanism and Effects of Human Tenocyte Coculture With Adipose-Derived Stem Cells.

PURPOSE: Adipose-derived stem cells (ASCs) are a potential candidate for cell-based therapy targeting tendon injury; however, their therapeutic benefit relies on their ability to interact with native tenocytes. This study examines the mechanism and effects of coculturing human tenocytes and ASCs. METHODS: Tenocytes (T) were directly cocultured with either ASCs (A) or fibroblasts (F) (negative control) in the following ratios: 50% T/50% A or F; 25% T/75% A or F; and 75% T/25% A or F. Cells were indirectly cocultured using a transwell insert that allowed for exchange of soluble factors only. Proliferation and collagen I production were measured and compared with monoculture controls. Synergy was quantified using the interaction index (II), which normalizes measured values by the expected values assuming no interaction (no synergy when II = 1). The ability of ASCs to elicit tenocyte migration was examined in vitro using a transwell migration assay and ex vivo using decellularized human flexor tendon explants. RESULTS: Compared with monoculture controls, II of proliferation was greater than 1 for all tenocyte and ASC direct coculture ratios, but not for tenocyte and fibroblast direct coculture ratios or for tenocyte and ASC indirect coculture. The ASCs elicited greater tenocyte migration in vitro and ex vivo. The II of collagen I production was greater than 1 for direct coculture groups with 25% T/75% A and 75% T/25% A. CONCLUSIONS: Direct coculture of ASCs and tenocytes demonstrated synergistic proliferation and collagen I production, and ASCs elicited tenocyte migration in vitro and ex vivo. These interactions play a key role in tendon healing and were absent when ASCs were replaced with fibroblasts, supporting the use of ASCs for cell-based therapy targeting tendon injuries. CLINICAL RELEVANCE: When ASCs are delivered for cell-based therapy, they directly interact with native tenocytes to increase cell proliferation, collagen I production, and tenocyte migration, which may enhance tendon healing.

De Novo Upper Extremity Lymphedema After Elective Hand Surgery in Breast Cancer Survivors.

BACKGROUND: The safety of elective hand surgery in breast cancer (BC) survivors is controversial because of concerns of developing upper extremity lymphedema. This study aimed to evaluate the risk of developing lymphedema after elective hand surgery among patients that underwent ipsilateral axillary lymph node dissection (ALND), sentinel lymph node biopsy (SLNB), and/or radiation therapy (RT). METHOD: A retrospective cohort of BC patients treated with ALND, SLNB, and/or RT was identified (1997-2012). Patients with subsequent ipsilateral elective hand surgery were included if greater than 1 year of follow-up and no preexisting lymphedema. The primary outcome was lymphedema after hand surgery. Comparisons between patients with and without lymphedema were made to identify potential lymphedema risk factors. Dichotomous and continuous variables were compared with Fisher exact and Student t tests, respectively. RESULTS: The analysis included 103 patients, of which 4 (3.8%) had documented lymphedema after hand surgery. Lymphedema developed early and was self-limited. Lymphedema was not related to age and type of hand surgery. Tourniquet time was longer in the nonlymphedema group. The lymphedema group all received adjuvant chemotherapy and RT with either ALND or SLNB. Patients with lymphedema had a shorter interval between hand surgery and completion of BC surgery (2.1 vs 6.2 years) and RT (2.0 vs 3.3 years). CONCLUSIONS: Lymphedema is uncommon after elective hand surgery among survivors and was not associated with tourniquet use. The combination of adjuvant therapies and axillary procedures and a short temporal relationship of these to hand surgery may increase lymphedema risk.

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.

Management of frontal sinus fractures: treatment modality changes at a level I trauma center.

The optimal management of frontal sinus fractures remains controversial, and previously accepted indications for surgical intervention are being challenged. The goals of this study were to determine how frontal sinus fracture management has changed at a single institution across multiple disciplines and to evaluate the long-term outcomes of operative and nonoperative treatment modalities.Patients treated for a frontal sinus fracture at Stanford Hospital and Clinics between June 1998 and June 2009 were included in the study. Inpatient records, clinic notes, operative reports, and radiographic studies were reviewed. The patients were invited for a follow-up clinic visit, physical examination, and focused sinus computed tomography. For a period of 11 years, 124 patients were treated for a frontal sinus fracture by physicians from 3 surgical subspecialties: otolaryngology, plastic surgery, and neurosurgery. A low short-term complication rate was observed (5.6%), and there was a trend toward nonsurgical management within the study population. Ten patients returned for a long-term follow-up. Of these, the 2 patients who underwent cranialization experienced as many or more long-term complications compared with the patients treated by other modalities. These complications included abnormal frontal bone contour with bony discontinuity and altered sensation in the distribution of the trigeminal nerve.The demonstrated trend toward nonsurgical management of frontal sinus fractures seems to be safe. In the limited group of patients who returned for follow-up, more long-term complications were observed in the patients who underwent cranialization. However, a larger long-term follow-up cohort will be necessary to elucidate the relationship between treatment modality and long-term outcomes and complications.

The Role of Electrical Stimulation in Peripheral Nerve Regeneration: Current Evidence and Future Directions.

The role of electrical stimulation in peripheral nerve regeneration is reviewed, including a brief background and proposed mechanism of action. Studies in animal as well as human models are reviewed. Current recommendations and future directions are addressed.

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.

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.

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.

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.

White light spectroscopy for free flap monitoring.

White light spectroscopy non-invasively measures hemoglobin saturation at the capillary level rendering an end-organ measurement of perfusion. We hypothesized this technology could be used after microvascular surgery to allow for early detection of ischemia and thrombosis. The Spectros T-Stat monitoring device, which utilizes white light spectroscopy, was compared with traditional flap monitoring techniques including pencil Doppler and clinical exam. Data were prospectively collected and analyzed. Results from 31 flaps revealed a normal capillary hemoglobin saturation of 40-75% with increase in saturation during the early postoperative period. One flap required return to the operating room 12 hours after microvascular anastomosis. The T-stat system recorded an acute decrease in saturation from ~50% to less than 30% 50 min prior to identification by clinical exam. Prompt treatment resulted in flap salvage. The Spectros T-Stat monitor may be a useful adjunct for free flap monitoring providing continuous, accurate perfusion assessment postoperatively.