The effect of the number of strands and knot throws of core suture techniques on the mechanical properties of the repaired flexor tendon.

Flexor tendon injury is a common hand trauma that requires surgical repair. The objective was to compare the repaired strength and gliding resistance with a varied number of repair strands and of square knots using a two-strand-overhand locking (TSOL) knot. First, isolated suture loops with different number of suture strands and number of closing knots were compared in mechanical strength and failure mode. Then, 90 flexor digitorum profundus (FDP) tendons from turkey digits were used for the tendon repair experiment. Both phases followed a similar 3 × 3 matrix comparing the knot type including TSOL+1SK (square knot), TSOL+2SK, and TSOL+3 SK and repair techniques including two-, four-, and six-strand repairs techniques respectively. The repaired tendons were tested for tendon resistance against pulley (friction), maximum force, force at 2 mm displacement, stiffness, and failure mode. Increasing the number of strands and closing square knots increases the tensile strength and stiffness of flexor tendon repairs and isolated suture loops without a significant effect on tendon friction. An increase in the number of square knots have shown increased strength only in Pennington repair, which correlated with the increased number of knot unraveling, a weak knot failure model. Our data demonstrated that increasing the number of strands is effective for improving the overall strength of tendon repair. When a two-strand repair is chosen, increasing knot number can improve repair strength. However, the number of knots appears not affecting repair strength in six-strand repair technique.

Expanded Polytetrafluoroethylene Mesh in Chest-wall Reconstruction: A 27-year Experience.

OBJECTIVES: To evaluate the success of expanded polytetrafluoroethylene (ePTFE) mesh in chest-wall reconstruction. METHODS: We retrospectively reviewed patients who underwent ePTFE (Gore-Tex®) chest-wall reconstruction. The main outcome was a mesh-related event, defined as a mesh-related reoperation (e.g., mesh infection requiring debridement with/without explant, tumor recurrence with explant) and/or structural dehiscence/mesh loosening with/without a hernia. Demographics and surgical outcomes were reported. RESULTS: 246 reconstructions met inclusion (1994-2021). Fifty-five (22.4%) reconstructions had mesh-related events within a median of 1.08 years (IQR 0.08, 4.53) postoperatively; those without had a stable chest for a median of 3.9 years (IQR, 1.59, 8.23, p<0.001). Forty-one (16.6%) of meshes became infected, requiring reoperation. Eighty-eight percent (36/41) were completely explanted; 8.3% (3/36) required additional mesh placement. Predictors of mesh-related events were prior chest-wall radiation (OR=9.73, CI 3.47 to 30.10, p<0.001), higher BMI (OR 1.08, CI 1.01 to 1.16, p=0.019), and larger defects (OR 1.48, CI 1.02 to 2.17, p=0.042). The risk of mesh-related events with obesity was higher with prior chest-wall radiation. CONCLUSIONS: Most (78%) patients with an ePTFE mesh had a stable reconstruction after a median of 4 years. Obesity, larger defects, and prior chest-wall radiation were associated with a higher risk of a mesh-related event mostly due to mesh infections. Seventeen percent of reconstructions had reoperation for mesh infection; 88% were completely explanted. Only 8% required replacement mesh, suggesting that experienced surgeons can safely manage them without replacement. Future studies should compare various meshes for high-risk patients to help guide the optimal mesh selection.

Anticancer effects of thymoquinone in head and neck squamous cell carcinoma: A scoping review.

Objective: Thymoquinone (TQ), the active constituent of Nigella sativa, has been shown to have anticancer effects in head and neck squamous cell carcinoma (HNSCC). This review aims to outline the properties of TQ, the known drivers in HNSCC formation, and summarize the anticancer effects of TQ in SCC. Data Sources: Three databases (PubMed, Embase, and Google Scholar) were queried for the key words "thymoquinone squamous cell carcinoma." Review Methods: Publications that were not original research and publications that did not have full-text available for review were excluded. Results: Sixteen research articles met the inclusion criteria. Our review demonstrates that TQ-induced cytotoxicity is associated with increased expression and activity of the tumor suppressor p53, proapoptotic proteins Bax and caspases, as well as decreased expression and activity of antiapoptotic proteins Bcl-2 and Mdm2. Additionally, TQ modulates cell-survival pathways such as the PI3k/Akt pathway. TQ synergizes with therapeutics including cisplatin and radiation. Early TQ administration may prevent carcinogenesis via upregulation of antioxidant enzymes, and TQ administration in the presence of cancer can result in disease mitigation via induction of oxidative stress. Conclusion: TQ acts as an upregulator of proapoptotic pathways and downregulator of antiapoptotic pathways, modulates the oxidative stress balance in tumor development, and works synergistically alongside other chemotherapeutics to increase cytotoxicity. TQ has the potential to prevent carcinogenesis in patients who are at high-risk for SCC and adjuvant treatment for SCC patients undergoing conventional treatments. Future studies should aim to identify specific populations in which TQ's effects would be the most beneficial. Level of Evidence: Not available.

A review of the therapeutic potential of histone deacetylase inhibitors in rhabdomyosarcoma.

This review aims to summarize the putative role of histone deacetylases (HDACs) in rhabdomyosarcoma (RMS) and the effects of HDAC inhibitors (HDACi) on RMS by elucidating and highlighting known oncogenic pathways, mechanisms of resistance, and the synergistic potential of histone deacetylase inhibitors. We searched two databases (PubMed and Google Scholar) for the keywords "Rhabdomyosarcoma, histone deacetylase, histone deacetylase inhibitors." We excluded three publications that did not permit access to the full text to review and those that focus exclusively on pleiomorphic RMS in adults. Forty-seven papers met the inclusion criteria. This review highlights that HDACi induce cytotoxicity, cell-cycle arrest, and oxidative stress in RMS cells. Ultimately, HDACi have been shown to increase apoptosis and the cessation of embryonal and alveolar RMS proliferation in vivo and in vitro, both synergistically and on its own. HDACi contain potent therapeutic potential against RMS. This review discusses the significant findings and the biological mechanisms behind the anti-cancer effects of HDACi. Additionally, this review highlights important clinical trials assessing the efficacy of HDACi in sarcomas.

Evaluation of the Efficacy of an Online Learning Module to Increase Wound Care Theoretical Knowledge Amongst Medical Students.

OBJECTIVE: We developed and evaluated an online learning module for teaching wound care basics to junior medical learners, which was assessed for its ability to increase theoretical knowledge of wound care, and medical learners' perceptions on the use of an online module to teach wound care practices. DESIGN: Between February 2022 to November 2022, participants were enrolled into our unblinded, matched-pair single-arm study. Participants completed a pre- and postquiz prior to and after completing the online module, respectively. Scores on the pre- and postquiz were matched by participant and evaluated for improvement. The online module was composed of free text, animated videos with voiceovers, pictorial examples, and tables, as well as unscored knowledge checks, covering the categories of i) normal wound healing physiology, ii) describing wounds/assessment of wounds, iii) choosing dressings for wounds, and iv) addressing and understanding wound aetiologies, including diabetic, arterial, and venous ulcers. SETTING: Participants were enrolled at the University of Toronto in Toronto, Canada. PARTICIPANTS: Participants were recruited from the undergraduate medicine and physician assistant programs at the University of Toronto. Students were provided with information on how to participate in the study through email and in-person recruitment. Thirty-three participants entered the study, and 23 participants completed the study. RESULTS: Across all participants, the prequiz to postquiz score increase averaged 13.29%, representing a statistically significant increase (p = 0.0000013). Ten of the 20 questions and all question categories had a statistically significant increase in the postquiz scores. All respondents found the module very useful (67%) or extremely useful (33%) for learning wound care, and 67% were very satisfied overall with the quality of the module, with the remainder (33%) of respondents somewhat satisfied. CONCLUSIONS: Online learning modules are effective at increasing wound care knowledge in junior medical learners, with high satisfaction amongst learners.

Multi-Modal Deep Learning for Assessing Surgeon Technical Skill.

This paper introduces a new dataset of a surgical knot-tying task, and a multi-modal deep learning model that achieves comparable performance to expert human raters on this skill assessment task. Seventy-two surgical trainees and faculty were recruited for the knot-tying task, and were recorded using video, kinematic, and image data. Three expert human raters conducted the skills assessment using the Objective Structured Assessment of Technical Skill (OSATS) Global Rating Scale (GRS). We also designed and developed three deep learning models: a ResNet-based image model, a ResNet-LSTM kinematic model, and a multi-modal model leveraging the image and time-series kinematic data. All three models demonstrate performance comparable to the expert human raters on most GRS domains. The multi-modal model demonstrates the best overall performance, as measured using the mean squared error (MSE) and intraclass correlation coefficient (ICC). This work is significant since it demonstrates that multi-modal deep learning has the potential to replicate human raters on a challenging human-performed knot-tying task. The study demonstrates an algorithm with state-of-the-art performance in surgical skill assessment. As objective assessment of technical skill continues to be a growing, but resource-heavy, element of surgical education, this study is an important step towards automated surgical skill assessment, ultimately leading to reduced burden on training faculty and institutes.

Three-Dimensional Engineered Peripheral Nerve: Toward a New Era of Patient-Specific Nerve Repair Solutions.

Reconstruction of peripheral nerve injuries (PNIs) with substance loss remains challenging because of limited treatment solutions and unsatisfactory patient outcomes. Currently, nerve autografting is the first-line management choice for bridging critical-sized nerve defects. The procedure, however, is often complicated by donor site morbidity and paucity of nerve tissue, raising a quest for better alternatives. The application of other treatment surrogates, such as nerve guides, remains questionable, and it is inefficient in irreducible nerve gaps. More importantly, these strategies lack customization for personalized patient therapy, which is a significant drawback of these nerve repair options. This negatively impacts the fascicle-to-fascicle regeneration process, critical to restoring the physiological axonal pathway of the disrupted nerve. Recently, the use of additive manufacturing (AM) technologies has offered major advancements to the bioengineering solutions for PNI therapy. These techniques aim at reinstating the native nerve fascicle pathway using biomimetic approaches, thereby augmenting end-organ innervation. AM-based approaches, such as three-dimensional (3D) bioprinting, are capable of biofabricating 3D-engineered nerve graft scaffolds in a patient-specific manner with high precision. Moreover, realistic in vitro models of peripheral nerve tissues that represent the physiologically and functionally relevant environment of human organs could also be developed. However, the technology is still nascent and faces major translational hurdles. In this review, we spotlighted the clinical burden of PNIs and most up-to-date treatment to address nerve gaps. Next, a summarized illustration of the nerve ultrastructure that guides research solutions is discussed. This is followed by a contrast of the existing bioengineering strategies used to repair peripheral nerve discontinuities. In addition, we elaborated on the most recent advances in 3D printing and biofabrication applications in peripheral nerve modeling and engineering. Finally, the major challenges that limit the evolution of the field along with their possible solutions are also critically analyzed. Impact statement Complex nerve injuries, including critical-sized gaps (>3 cm loss of substance), gaps involving nerve bifurcations, and those associated with ischemic environments, are difficult to manage. A biomimetic, personalized peripheral nerve tissue surrogate to address these injuries is lacking. The peripheral nerve repair market currently represents a multi-billion-dollar industry that is projected to expand. Given the clinical and economical dilemmas posed by this medical condition, it is crucial to devise novel and effective nerve substitutes. In this review article, we discuss progress in three-dimensional printing technologies, including biofabrication and nerve computer-aided design modeling, toward achieving a patient-specific and biomimetic nerve repair solution.

Arthroscopic Simulation: The Future of Surgical Training: A Systematic Review.

BACKGROUND: Arthroscopic simulation has rapidly evolved recently with the introduction of higher-fidelity simulation models, such as virtual reality simulators, which provide trainees an environment to practice skills without causing undue harm to patients. Simulation training also offers a uniform approach to learn surgical skills with immediate feedback. The aim of this article is to review the recent research investigating the use of arthroscopy simulators in training and the teaching of surgical skills. METHODS: A systematic review of the Embase, MEDLINE, and Cochrane Library databases for English-language articles published before December 2019 was conducted. The search terms included arthroscopy or arthroscopic in combination with simulation or simulator. RESULTS: We identified a total of 44 relevant studies involving benchtop or virtually simulated ankle, knee, shoulder, and hip arthroscopy environments. The majority of these studies demonstrated construct and transfer validity; considerably fewer studies demonstrated content and face validity. CONCLUSIONS: Our review indicates that there is a considerable evidence base regarding the use of arthroscopy simulators for training purposes. Further work should focus on the development of a more uniform simulator training course that can be compared with current intraoperative training in large-scale trials with long-term follow-up at tertiary centers.

Development of the Diabetic Wound Assessment Learning Tool (DiWALT) and validity evidence.

OBJECTIVE: Diabetic foot wounds account for up to one-third of diabetes-related health care expenditure and are the greatest cause of extremity amputation in Canada. Physicians encounter patients with such wounds in all specialties, particularly as generalists in medical wards and emergency departments. However, there is a dearth of literature on the optimal way to teach and to assess the management of these patients. Given the importance of assessment for learning in the shift toward competency-based medical education, we aimed to develop an assessment tool and to build validity evidence for its use in this context. METHODS: A consensus process involving nine Canadian experts in diabetic wound management was used to develop the Diabetic Wound Assessment Learning Tool (DiWALT) items and two 10-minute simulation-based testing scenarios. The simulators used were modified from commercially available models to serve the testing scenarios. Validity evidence for the DiWALT was subsequently evaluated by assessing 24 physician participants' performance during the two scenarios. All participants were novices (<50 cases managed). Two assessors independently rated participants using the DiWALT. Evidence was organized using Kane's validity framework and included Cronbach α for interitem consistency as well as test-retest and inter-rater reliability using the intra-class correlation coefficient (ICC). RESULTS: Cronbach α was 0.92, implying high internal consistency. Test-retest reliability was also excellent with ICC of 0.89 (confidence interval [CI], 0.76-0.95) for single measures and ICC of 0.94 (CI, 0.86-0.98) for average measures. Inter-rater reliability was fair for single measures with ICC of 0.68 (CI, 0.65-0.71) and good for average measures with ICC of 0.81 (CI, 0.79-0.83). CONCLUSIONS: These results demonstrate that the DiWALT consistently and reliably evaluates competence in diabetic wound management during simulated cases using a small, homogeneous sample of physicians. Further work is necessary to quantify sources of error in the assessment scores, to establish validity evidence when it is used to assess larger and more heterogeneous participants, and to identify how well the DiWALT differentiates between different experience levels.