Evaluating the Effectiveness of Commercially Available Antiadhesion Tendon Protector Sheets in Tendon Repair Surgery Versus Tendon Repair Surgery Alone: A Preclinical Model Study.

PURPOSE: Adhesion formation is the major complication after tendon repairs that halts functional restoration and causes disability in patients. This study aimed to compare the antiadhesion efficacy of two tendon protector sheets using a previously established turkey flexor tendon model. METHODS: Twenty-four adult Bourbon Red turkeys were randomized into three groups: (1) control, (2) type I collagen-glycosaminoglycan (Collagen-GAG), and (3) hyaluronic acid. In each group, the flexor digitorum profundus tendon of the middle digit was sharply lacerated at the proximal interphalangeal joint level. All operated feet were immobilized until sacrifice 6 weeks after the surgery. After sacrifice, the repaired and normal digits were collected for biomechanical testing, adhesion scores, histological examination, and adhesion-related gene expression analysis. RESULTS: At 42 days after tendon repair, the normalized work of flexion of the repaired digit was the lowest in the Collagen-GAG group. The Collagen-GAG group also had the lowest gross adhesion score, indicating minimal adhesion. The hyaluronic acid group showed lower adhesion scores compared with the control, but the difference was not statistically significant. Microscopically, the Collagen-GAG group had a significantly lower histological adhesion score than the control group. In the Collagen-GAG group, the gene expression levels of WNT3A, WNT5A, and WNT7A were suppressed. CONCLUSIONS: In an avian model of flexor tendon repair, the application of tendon protector sheets reduces peritendinous fibrotic tissue formation histologically. CLINICAL RELEVANCE: There are currently limited commercially available products to reduce postoperative peritendinous adhesions. Further validation is needed to confirm the effectiveness of tendon protector sheets in improving surgical outcomes following tendon repairs.

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.

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.

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.

OBJECTIVE: The study objective was to evaluate the success of expanded polytetrafluoroethylene mesh in chest-wall reconstruction. METHODS: We retrospectively reviewed patients who underwent expanded polytetrafluoroethylene (Gore-Tex) chest-wall reconstruction. The main outcome was a mesh-related event, defined as a mesh-related reoperation (eg, mesh infection requiring debridement with/without explant, tumor recurrence with explant) or structural dehiscence/mesh loosening with/without a hernia. Demographics and surgical outcomes were reported. RESULTS: A total of 246 reconstructions met inclusion (1994-2021). Fifty-five reconstructions (22.4%) had mesh-related events within a median of 1.08 years (interquartile range, 0.08-4.53) postoperatively; those without had a stable chest for a median of 3.9 years (interquartile range, 1.59-8.23, P < .001). Forty-one meshes (16.6%) 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 (odds ratio, 9.73, CI, 3.47-30.10, P < .001), higher body mass index (odds ratio, 1.08, CI, 1.01-1.16, P = .019), and larger defects (odds ratio, 1.48, CI, 1.02-2.17, P = .042). The risk of mesh-related events with obesity was higher with prior chest-wall radiation. CONCLUSIONS: Most patients (78%) with an expanded polytetrafluoroethylene 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.

Ultrasound Shear Wave Elastography for Noninvasive Diagnosis of Acute Compartment Syndrome Using a Novel In Vivo Turkey Model.

INTRODUCTION: Acute Compartment Syndrome (ACS) is a severe trauma caused by elevated intra-muscle-compartment pressure (ICP). The current standard method for diagnosis is to insert a needle into the muscle sterilely under anesthesia. However, to secure the environment is sometimes not easy and leads to delays in diagnosis. Recently, we have focused on shear wave ultrasound elastography (SWE) as an alternative, which can be done concisely in unclean environment and without anesthesia. We would like to report the usefulness of SWE for ACS diagnosis using 2-pedal walking turkey model recently developed in our lab. MATERIALS AND METHODS: A total of 32 1-year-old Bourbon turkeys were used. 5% solution of chicken albumin was infused continuously into the tibialis cranialis (TC) muscle using IV pump. The ICP was increased stepwise from 0 to 50 mmHg. During the rising of ICP, the correlation between values of SWE (kPa) and ICP (mmHg) was measured. After the ICP reached 50 mmHg, half of the turkeys were maintained at this pressure for 2 hours and the rest for 6 hours. After infusion, a fasciotomy was performed on the half turkey. Half of the turkeys were euthanized after 2 weeks and the rest after 6 weeks. SWE of TC muscle and walking gait data on turkeys using a portable walkway system were measured weekly until euthanasia. At euthanasia, isometric tetanic muscle force (ITF) tests to TC muscle and histological evaluations were performed. RESULTS: SWE value (kPa) was highly significantly correlated to the actual ICP (mmHg) (R2 = 0.91). Stance of ACS side leg were significantly extended, and swing of the control side shortened from the second to the third week after ACS in the 6 hours infusion-no-fasciotomy group (P < 0.05*). ITF was significantly reduced mainly in the 6 hours infusion group (P < 0.05*). Histological evaluation revealed that in the 6 hours infusion and 6 weeks survival group, both the muscle fiber and intercellular distances were significantly expanded (P < 0.05). CONCLUSION: SWE seems to be a substitute measure of ICP in diagnosing ACS. With regard to our in vivo ACS model using turkey, survival at 50 mmHg ICP for 6 hours and 6 weeks post ACS would be an appropriate situation.

Early detection of myocardial iron overload in patients with ß-thalassemia major using cardiac magnetic resonance T1 mapping.

BACKGROUND: The T2* technique, used for quantifying myocardial iron content (MIC), has limitations in detecting early myocardial iron overload (MIO). The in vivo mapping of the myocardial T1 relaxation time is a promising alternative for the early detection and management of MIO. METHODS: 32 ß-thalassemia major (ßTM) patients aged 11.5 ± 4 years and 32 healthy controls were recruited and underwent thorough clinical and laboratory assessments. The mid-level septal iron overload was measured through T1 mapping using a modified Look-Locker inversion recovery sequence with a 3 (3 s) 3 (3 s) 5 scheme. Septum was divided at the mentioned level into 3 zones corresponding to segments 8 and 9 in the cardiac segmentation model. RESULTS: 21.9 % of ßTM had clinical cardiac morbidity. The cut-off of T1 mapping of hepatic and myocardium to differentiate between the patients and control groups was ≤466 and ≥ 923 ms respectively. The T1 technique was able to detect 4 patients with high MIC, two of them were not detected by the T2* technique. There was a statistically significant correlation between the average T1 values of the studied zones in patients with ßTM and the liver iron content (LIC), the T1 values within segment 8 of the liver, age of patients, the age at first transfusion, age of splenectomy and serum ferritin value. CONCLUSION: The addition of the T1 mapping sequence to the conventional T2* technique was able to increase the efficacy of the MIC detection protocol by earlier detection of MIO. This would guide chelation therapy to decrease myocardial morbidity.

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.

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.

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.

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.