Cadaveric Model Research Articles

Thiel cadaver eye as a training model for sub-Tenon’s blocks: a feasibility study

BackgroundRegional anaesthesia education, especially for ocular procedures, necessitates reliable surgical training models. While cadaveric models offer anatomical fidelity, conventional embalming methods may compromise tissue integrity. We aimed to assess the effectiveness of Thiel cadavers for training in sub-Tenon’s blocks by evaluating ocular tissues and measuring insertion forces.MethodsExperimental design, using twenty eyes from ten Thiel cadaver heads. These cadavers were specifically prepared to test the administration of sub-Tenon’s blocks. The research was conducted in a controlled laboratory setting appropriate for handling cadaveric materials and conducting precise measurements. Each cadaver eye underwent an initial ultrasound examination, and its axial length was noted. An intravitreal injection of heptastarch solution followed, to re-establish the eye’s sphericity. After this volume injection, the axial length and intraocular pressure were measured again. Mock sub-Tenon’s blocks were administered in 2 separate quadrants of the eye, with insertion forces measured using a pressure gauge. These were compared to a data set of insertion forces measured in a series of isolated pig’s eyes on which STBs had been performed. Main outcome measurements were macroscopic assessment of the ocular tissue layers and the insertion forces required for the sub-Tenon’s blocks. In a second set of 10 Thiel cadaver heads, 5 ml of sodium chloride were injected as sub-Tenon’s blocks and the emergence of a periocular “T-sign” ascertained and measured by ultrasound.ResultsFour of twenty eyes (20%) retained near-natural sphericity, with the remaining requiring volume injection to approximate physiological shape and pressure. The conjunctiva and Tenon’s layer were intact, and correct cannula placement was achieved in all cases. In 16 of 20 eyes where T-signs could be measured, the median thickness of the T-sign amounted to 2.72 mm (range 1.34 mm–5.28 mm). The average maximum cannula insertion force was 2.92 Newtons. Insertion forces in intact Thiel cadaver heads were consistently higher than in isolated pig’s eyes (3.6 N vs 2.0 N).ConclusionThese findings suggest that Thiel cadavers are a promising model for training in sub-Tenon’sblocks, despite the challenge of often desiccated and involuted eyes.

From FUSE to a hands-on electrosurgery course using a cadaveric model.

Surgical procedures in contemporary practice frequently employ energy-based devices, yet comprehensive education surrounding their safety and effectiveness remains deficient. We propose an innovative course for residents that aims to provide basic electrosurgery knowledge and promote the safe use of these devices. We developed a simulated training course for first-year general surgery and orthopedic residents. First, a survey was conducted regarding their knowledge perception about energy devices. The course consisted of two online theoretical sessions, followed by three in-person practical sessions. First-year residents performed three video-recorded attempts using a cadaveric model and were assessed through a digital platform using the Objective Structured Assessment of Technical Skill (OSATS), a Specific Rating Scale (SRS), and a surgical energy-based devices scale (SEBS). Third-year residents were recruited as a control group. The study included 20 first-year residents and 5 third-year residents. First-year residents perceived a knowledge gap regarding energy devices. Regarding practical performance, both OSATS and checklist scores were statistically different between novices at their first attempt and the control group. When we analyzed the novice's performance, we found a significant increase in OSATS (13 vs 21), SRS (13 vs 17.5), and SEBS (5 vs 7) pre- and post-training scores. The amount of feedback referred to skin burns with the electro-scalpel reduced from 18 feedbacks in the first attempt to 2 in the third attempt (p-value = 0.0002). When comparing the final session of novices with the control group, no differences were found in the SRS (p = 0.22) or SEBS (p = 0.97), but differences remained in OSATS (p = 0.017). This study supports the implementation of structured education in electrosurgery among surgical trainees. By teaching first-year residents about electrosurgery, they can acquire a skill set equivalent to that of third-year residents. The integration of such courses can mitigate complications associated with energy device misuse, ultimately enhancing patient safety.

Evaluation of Tibiofemoral Contact Mechanics After a Novel Hybrid Procedure for Femoral Osteochondral Defect Repairs With a Subchondral Implant and Dermal Matrix.

There is a lack of procedures that adequately address the subchondral bone structure and function for reconstructing osteochondral defects in the femoral condyles. To biomechanically evaluate the tibiofemoral joint contact characteristics before and after reconstruction of femoral condylar osteochondral defects using a novel hybrid reconstructive procedure, which was hypothesized to restore the contact characteristics to the intact condition. Controlled laboratory study. Tibiofemoral contact areas, contact forces, and mean contact pressures were measured in 8 cadaveric knees (mean age 52 ± 11 years; 6 women, 2 men) using a custom testing system and pressure mapping sensors. Five conditions were tested for each condyle: intact, 8-mm defect, 8-mm repair, 10-mm defect, and 10-mm repair. Medial femoral condylar defects were evaluated at 30° of knee flexion and lateral condylar defects were evaluated at 60° of knee flexion, with compressive loads of 50, 100, and 150 N. The defects were reconstructed with a titanium fenestrated threaded implant countersunk in the subchondral bone and an acellular dermal matrix allograft. Repeated-measures analysis of variance with Bonferroni correction for multiple comparisons was used to compare the results between the 5 testing conditions at each load. Medial condylar defects significantly increased mean contact pressure on the lateral side (P < .042), which was restored to the intact levels with repair. The lateral condylar defect decreased the mean contact pressure laterally while increasing the mean pressure medially. The lateral and medial mean contact pressures were restored to intact levels with the 8-mm lateral condylar defect repair. The medial mean contact pressure was restored to intact levels with the 10-mm lateral condylar defect repair. The lateral mean contact pressure decreased compared with the intact state with the lateral condylar 10-mm defect repair. Tibiofemoral joint contact pressure was restored to the intact condition after reconstruction of osteochondral defects with dermal allograft matrix and subchondral implants for the repair of both 8- and 10-mm lateral condylar defects as well as 8-mm medial condylar defects but not completely for 10-mm medial condylar defects. The novel hybrid procedure for osteochondral defect repair restored tibiofemoral joint contact characteristics to normal in a cadaveric model.

Nonspherical humeral arthroplasty increases internal rotation: a biomechanical comparison of the native humeral head to nonspherical and spherical humeral implants

BackgroundNonspherical humeral head implants more closely resemble native humeral anatomy than spherical components and may better replicate native shoulder range of motion (ROM) and kinematics. The purpose of this study was to compare shoulder ROM and kinematics of a commercially available nonspherical humeral head implant with the native humeral head and a height matched, custom manufactured spherical implant. MethodsSix fresh frozen cadaveric shoulder specimens were used with a custom shoulder testing system. The native shoulder was tested in multiple positions under anatomic muscle loading. Each specimen was tested for ROM and glenohumeral joint kinematics by measuring the humeral head apex and humeral head center (HHC) translation per degree of rotation using a MicroScribe digitizer. Measurements were then repeated after implantation of a spherical and, subsequently, a nonspherical humeral head prothesis. ResultsThe nonspherical implant had significantly more internal rotation (IR) compared to the spherical implant at 0° abduction (10.6 ± 6.2° more IR, P = .004, 95% confidence interval [CI]: −13.3, 34.5), 30° abduction (5.7 ± 2.8°, P = .009, 95% CI: −12.6, 24.0) and 60° abduction (6.8 ± 2.7°, P = .002, 95% CI: −8.3, 22.1) in the scapular plane, and 60° abduction (6.9 ± 2.0°, P = .031, 95% CI: −12, 25.6) in the coronal plane. The nonspherical implant had more IR than the native head at 60° of abduction in the scapular plane (7.0 ± 2.2° P = .002, 95% CI: −10.3, 24.3). The spherical head had less IR than the native head at 0° abduction (7.2 ± 4.8°, P = .031, 95% CI: 32.5, 18.1). There were no differences in humeral head apex translation per degree of rotation noted between the spherical implant or nonspherical implant and the native shoulder. The nonspherical head had less HHC translation than the native shoulder at 30° abduction in the forward flexion plane (P = .007); otherwise, there were no statistically significant differences in HHC translation between the native shoulder, the spherical head, and the nonspherical head. There was no significant difference observed between the average difference in anterior-posterior and superior-inferior radius of curvature of the nonspherical implants (2.0 ± 0.7 mm) and the native humeral heads (1.9 ± 1.3 mm) [P = .926]. ConclusionThe results of this biomechanical study suggest that the commercially available nonspherical humeral head has improved IR when compared to a custom, height controlled spherical implant and offers ROM and kinematics similar to the native humeral head in a cadaveric model.

489. EVALUATION OF THE ONCOLOGICAL QUALITY OF MINIMALLY INVASIVE TRANSCERVICAL OESOPHAGECTOMY (MICE) USING A CADAVERIC MODEL

Abstract Background Nodal involvement is a well-known factor of poor prognosis for esophageal cancer, but the extent of the lymph node dissection, or the number of the dissected lymph nodes, remains controversial questions. Western guidelines (ESMO and NCCN) suggest accomplishing esophagectomy with en-bloc two-field lymphadenectomy. Minimally Invasive transCervical oEsophagectomy (MICE) is a novel technique for the minimally invasive treatment of esophageal cancer. In the literature, the radicality of this procedure still remains unknown, as evidenced by studies conducted in Eastern countries. This descriptive study explores feasibility of MICE in Western countries using a cadaveric model. Methods A cadaver study was conducted in a real operating room setting, with bilateral lung ventilation induced to replicate a real-life situation. Mediastinal dissection was carried out via single port left transcervical mediastinoscopy. Subsequently, a right thoracoscopy in prone position was performed to access the clearance of the fatty tissue at the anatomical boundaries of the lymph node stations. The finalization of the dissection of the lower mediastinum via transhiatal approach was not performed because it was not in the aim of the study. The extent and the radicality of the dissection were evaluated by an independent external expert. Results Results indicated effectiveness of MICE in dissecting lymph nodes around the lower and middle esophagus, as well as at the subcarinal station. At the upper esophagus level, harvesting was complete on the left side but some residual tissue was found on the right-side at the right recurrent laryngeal nerve and on the right pleura, this result was attributed to technical difficulty. Conclusion The findings suggest that MICE is adequate in accomplish a complete dissection of lymph nodes around the mediastinal esophagus, including a complete subcarinal dissection, adhering to Western lymphadenectomy standards. Further descriptive study on cadaver will help to understand if a more extensive lymphadenectomy is achievable.

Both Single- and Double-anchor Remplissage Techniques Restore Native Stability in a Cadaveric Model of Hill-Sachs Lesions in Anterior Shoulder Instability

Both Single- and Double-anchor Remplissage Techniques Restore Native Stability in a Cadaveric Model of Hill-Sachs Lesions in Anterior Shoulder Instability

Load Distribution After Serial Resection of the Posterior Horn of the Lateral Meniscus and Subsequent Meniscal Allograft Transplant: A Biomechanical Study

Background: Data are lacking as to when a meniscal allograft transplant (MAT) may be biomechanically superior to a partially resected lateral meniscus. Hypothesis: Lateral MAT using a bone bridge technique would restore load distribution and contact pressures in the tibiofemoral joint to levels superior to those of a partial lateral meniscectomy. Study Design: Controlled laboratory study. Methods: Eleven fresh-frozen human cadaveric knees were evaluated in 5 lateral meniscal testing conditions (native, one-third posterior horn meniscectomy, two-thirds posterior horn meniscectomy, total meniscectomy, MAT) at 3 flexion angles (0°, 30°, and 60°) under a 1600-N axial load. Pressure sensors were used to acquire contact pressure, contact area, and peak contact pressure within the tibiofemoral joint. Results: Limited (one-third and two-thirds) partial lateral posterior horn meniscectomy showed no significant increase in mean and peak contact pressures as well as no significant decrease in contact area compared with the intact state. Total meniscectomy significantly increased mean contact pressure at 0° and 30° (P = .008 and P < .001, respectively), increased peak contact pressure at 30° (P = .04), and decreased mean contact area in all flexion angles compared with the native condition (P < .01). Lateral MAT significantly improved mean contact pressure compared with total meniscectomy at 0° and 30° (P = .002 and P = .003, respectively) and increased contact area at 30° and 60° (P = .003 and P = .009, respectively), although contact area was still significantly smaller (24.1%) after MAT relative to the native meniscus (P = 0.015). However, allograft transplant did not result in better tibiofemoral contact biomechanics compared with limited partial meniscectomy (P > .05). Conclusion: The peripheral portion of the lateral meniscus provided the most important contribution to the distribution of contact pressure across the tibiofemoral joint in the cadaveric model. Total meniscectomy significantly increased mean and peak contact pressure in the cadaveric model and decreased contact area. Lateral MAT restored contact biomechanics close to normal but was not superior to the partially meniscectomized status. Clinical Relevance: Surgeons should attempt to preserve a peripheral rim of the posterior lateral meniscus. Meniscal allograft transplant appears to improve but not normalize mean contact pressure and contact area relative to total lateral meniscectomy.

Teaching medical students ultrasound-guided needle aspiration of synthetic cysts: effect of a formalin-embalmed cadaver simulation model

BackgroundStandard training for ultrasound-guided cyst needle aspiration is currently performed on live patients during residency. This practice presents risk of iatrogenic injury to patients and provides a high-stress learning environment for medical trainees. Simulation training using synthetic cysts in a formalin-embalmed cadaver model may allow for realistic, practical, and effective training free from patient risk.MethodsThirty first-year medical students viewed an orientation video, then attended a skills workshop to perform cyst needle aspiration in formalin-embalmed cadaver tissue under ultrasound guidance. Participants were randomly assigned to one of three ultrasound-trained instructor-types which included a medical student, clinical anatomist, or an ultrasound fellowship trained emergency medicine physician. After training, participants underwent a 5-min skills test to assess their ability to drain a synthetic cyst independently. Pre- and post-training self-confidence surveys were administered.ResultsUltrasound images of synthetic cysts in formalin-embalmed tissue were clear and realistic in appearance, and sonographic needle visualization was excellent. Participants took an average of 161.5 s and 1.9 attempts to complete the procedure. Two of the 30 participants could not complete the procedure within the time limit. Participants’ self-reported confidence with respect to all aspects of the procedure significantly increased post-training. Mean confidence scores rose from 1.2 (95% CI 0.96 to 1.39) to 4.4 (95% CI 4.09 to 4.53) (P < 0.0001) Procedure time, number of attempts, performance scores, and self-confidence outcomes were not significantly affected by instructor type.ConclusionsThe use of synthetic cysts in formalin-embalmed cadaveric tissue is feasible, realistic, and efficacious for the teaching of ultrasound-guided needle aspiration to novice medical trainees. This simulation training method can be delivered effectively by multiple instructor types and may allow medical trainees to increase their tactical skill and self-confidence prior to performing ultrasound-guided cyst needle aspiration on live patients.

Baseline-to-loaded changes in regional tibial cartilage thickness, T1ρ and T2: Utilization of an MRI compatible loading device.

The objective of the study was to evaluate tibial cartilage thickness (TCT), T1ρ and T2 values within both loaded and baseline configurations in a cadaveric knee model using a 3D bone based tibial coordinate system. Ten intact cadaveric knees were mounted into an magnetic resonance imaging (MRI) compatible loading device. Morphologic and quantitative MRI (qMRI) images were acquired with the knee in a baseline configuration and after application of 50% body weight. The morphologic images were evaluated for cartilage degeneration using a modified Noyes scoring system. A 3D bone-based tibial coordinate system was utilized to evaluate regional changes of tibial T1ρ, T2, and cartilage thickness values among regions covered and uncovered by the meniscus. Inter-regional differences in medial and lateral MRI outcomes were found between loaded and baseline configurations. Cartilage regions covered by the meniscus demonstrated disparate qMRI and TCT results as compared to cartilage regions not covered by the meniscus. The regions covered by meniscus experienced a ~3.5%, ~0.5%, and ~5.5% reduction of T1ρ (p < 0.05, medial and lateral compartments), T2 and TCT, respectively, in both compartments while regions not covered by the meniscus experienced larger reductions of ~10%, ~2%, and ~10.5% reduction of T1ρ (p < 0.05, medial and lateral compartments), T2 and TCT (p < 0.05, lateral compartment only), respectively, in both compartments. T1ρ and T2 decreases following application of 50% body weight load were substantially larger in the tibial regions with modified Noyes grade 3 (n = 2) compared to either healthy regions (n = 85, p < 0.0.003) or regions with modified Noyes grade 2 (n = 13, p < 0.004). Interregional differences in MRI outcomes reflect variations in structure and function, and largely followed a pattern in cartilage regions that were covered or not covered by the meniscus. Results of the current study suggest that ΔT1ρ and ΔT2 values may be sensitive to superficial fissuring, more than baseline or loaded T1ρ or T2 values, or TCT alone, however future studies with additional specimens, with greater variability in OA grade distribution, may further emphasize the current findings.

Lateral Wall Integrity of the Greater Tuberosity Is Important for the Stability of Osteoporotic Proximal Humeral Fractures After Plate Fixation.

Previous studies assessing surgical fixation of osteoporotic proximal humeral fractures have primarily focused on medial calcar support. In this study, we utilized a specific model for 2-part surgical neck fracture of the osteoporotic proximal humerus to investigate how severe comminution of the greater tuberosity (GT) lateral wall affects biomechanical stability after fixation with a plate. Ten matched pairs of cadaveric humeri (right and left) were assigned to either a surgical neck fracture alone (the SN group) or a surgical neck fracture with GT lateral wall comminution (the LW group) with use of block randomization. We removed 5 mm of the lateral wall of the GT to simulate severe comminution of the lateral wall. Axial compression stiffness, torsional stiffness, varus bending stiffness, and the single load to failure in varus bending were measured for all plate-bone constructs. Compared with the SN group, the LW group showed a significant decrease in all measures, including torsional stiffness (internal, p = 0.007; external, p = 0.007), axial compression stiffness (p = 0.002), and varus bending stiffness (p = 0.007). In addition, the mean single load to failure in varus bending for the LW group was 62% lower than that for the SN group (p = 0.005). Severe comminution of the GT lateral wall significantly compromised the biomechanical stability of osteoporotic, comminuted humeral surgical neck fractures. Although the generalizability of this cadaveric model may be limited to the extreme clinical scenario, the model showed that severe comminution of the GT lateral wall significantly compromised the stability of osteoporotic humeral surgical neck fractures fixed with a plate and screws alone.

Anatomical evaluation of the superficial parasternal intercostal plane block

Background and objectivesFew cadaveric studies have evaluated the dye spread with superficial parasternal intercostal plane (SPIP) blocks. In this study, we examined the dye spread of an ultrasound-guided SPIP block...

Optimal caudal needle angulation for lumbar medial branch denervation: A 3D cadaveric and clinical imaging comparison study

BackgroundLumbar medial branch (MB) radiofrequency ablation is a common intervention to treat facetogenic low back pain. The consensus among spine pain interventionalists is that capturing a greater length of the MB correlates with a longer duration of pain relief. Therefore, there has been interest in defining optimal needle angles to achieve parallel cannula placement. Presently, there is inconsistency regarding the optimal caudal needle angles. ObjectivesThe objectives of this study were to: 1) use a dissection-based 3D modelling methodology to quantify optimal caudal needle angles from cadaveric models; and 2) compare optimal cadaver-derived caudal needle angles with real-world patient-derived needle angles. MethodsEighteen formalin embalmed lumbosacral spine specimens were dissected, digitized, and modelled in 3D. Virtual needles were simulated and placed parallel with the L1-L5 MBs. Cadaver-derived caudal needle angles were measured from the high-fidelity 3D models with optimally placed virtual needles. Lateral fluoroscopic images of patients (n = 200) that received lumbar MB denervation were reviewed to measure patient-derived caudal needle angles (L3-L5 MB levels). Descriptive statistics were used to analyze the cadaver (L1-L5 MB levels) and patient-derived (L3-L5 MB levels) caudal needle angles. The cadaver and patient-derived mean caudal needle angles for L3-L5 MB levels were compared. ResultsThere was variability in the cadaver-derived mean caudal needle angles. The lowest mean caudal needle angle was the L1 MB level measured at 41.57 ± 8.56° (range: 27.14° - 53.96°). The highest was the L5 MB level with a mean caudal needle angle of 60.79 ± 8.55° (range: 46.97° - 79.74°). A total of 123 patients were included and 369 caudal needle angles (L3-L5 MB levels) were measured and analyzed. There was variability in the patient-derived mean caudal needle angles. The patient-derived mean caudal needle angles were 29.18 ± 8.77° (range: 11.80° - 61.31°), 33.34 ± 7.23° (range: 16.40° - 54.15°), and 49.08 ± 8.87° (range: 26.45° - 76.95°) for the L3, L4, and L5 MB levels, respectively. There was a significant difference in mean caudal needle angle between cadaver and patient-derived needle angles at the L3, L4, and L5 MB levels. ConclusionsAnalysis of cadaver-derived needle angles versus patient-derived data suggests optimization of lumbar MB denervation requires greater caudal angulation to achieve parallel needle placement. Further research is required to assess the clinical implications.

ANATOMICAL STUDY OF PERCUTANEOUS TENOTOMY OF THE ILIOPSOAS TENDON GUIDED BY ULTRASOUND IN CADAVERS: A VIABLE TECHNIQUE?

The objective of this study is to evaluate the effectiveness and safety of percutaneous tenotomy of the iliopsoas tendon with the aid of ultrasound in cadavers.An anatomical and descriptive study of the technique of percutaneous tenotomy of the iliopsoas tendon guided by ultrasound and to share our experience in performing it and its reproducibility in clinical practice.Out of 20 tenotomies, 17 were total, performed at the level of the superior border of the acetabulum. Three tenotomies were partial, with more than 75% of the tendon being sectioned in all three. During one of the tenotomies, there was a partial injury to the femoral nerve. Measurements were made of the distance between the site where the blade was inserted and the femoral nerve, a noble structure that would be at greater risk during the procedure, with an average distance of 8.4 millimeters.Ultrasound-guided iliopsoas tendon release procedures have the ability to be performed in a cadaveric model, consistently achieving complete tendon release, except in cases of obesity, with minimal repercussions on adjacent structures, and require approximately 4 minutes to complete.

A new vessel filled and heart-beating human corpse model for VATS lobectomy training

BackgroundNowadays, video-assisted thoracic surgery (VATS) lobectomy represents the treatment of choice for early-stage lung cancer. Over the years, different methods for VATS training have evolved. The aim of this study is to present an innovative beating-heart filled-vessel cadaveric model to simulate VATS lobectomies.MethodsVia selective cannulation of the cadaver heart, the pulmonary vessels were filled with a gel to improve their haptic feedback. An endotracheal tube with a balloon on its tip then allowed movement of the heart chambers, transmitting a minimum of flow to the pulmonary vessels. A simulated OR was created, using all instrumentation normally available during surgery on living patients, with trainees constantly mentored by experienced surgeons. At the end of each simulation, the participants were asked 5 questions on a scale of 1 to 10 to evaluate the effectiveness of the training method (“1” being ineffective and “10” being highly effective).ResultsEight models were set up, each with a median time of 108 min and a cost of €1500. Overall, 50 surgeons were involved, of which 39 (78%) were consultants and 11 (22%) were residents (PGY 3–5). The median scores for the 5 questions were 8.5 (Q1; IQR1–3 8-9), 8 (Q2; IQR1–3 7–9), 9 (Q3; IQR1–3 8–10), 9 (Q4; IQR1–3 8–10), and 9 (Q5; IQR1–3 8–10). Overall, the model was most appreciated by young trainees even though positive responses were also provided by senior surgeons.ConclusionsWe introduce a new beating-heart filled-vessel cadaveric model to simulate VATS lobectomies. From this initial experience, the model is cost effective, smooth to develop, and realistic for VATS simulation.

How Strong Is the Ligamentum Teres of the Hip? A Biomechanical Analysis.

Intraarticular hip pain represents a substantial clinical challenge, with recent studies implicating lesions in the ligamentum teres as potential contributors. Even more so, damage to the ligamentum teres is particularly prevalent among young patients undergoing joint-preserving interventions. Although several studies have investigated the biomechanical attributes of the ligamentum teres, inconsistencies in reported findings and reliance on cadaveric or animal models have raised concerns regarding the extrapolation of results to clinical practice. Furthermore, there is a lack of research examining ligamentum teres biomechanics specifically within the relevant patient cohort-individuals who benefit from joint-preserving surgical interventions. We sought (1) to determine the biomechanical properties (ultimate load to failure, tensile strength, stiffness, and elastic modulus) of fresh-frozen ligaments from patients undergoing surgical hip dislocation, and (2) to identify patient-specific factors that are associated with them. This was an institutional review board-approved study on intraoperatively harvested ligamentum teres from 74 consecutive patients undergoing surgical hip dislocation for joint preservation (August 2021 to September 2022). After the exclusion of patients with previous surgery, posttraumatic deformities, avascular necrosis, slipped capital femoral epiphysis, and Perthes disease, 31 ligaments from 31 patients were analyzed. The mean age of the study group was 27 ± 8 years, and 61% (19) of participants were male. The main indication for surgery was femoroacetabular impingement. Standardized AP pelvic and axial radiographs and CT scans were performed in all patients for better radiological description of the population and to identify associated radiological factors. The ligament was thoroughly transected at its origin on the fossa acetabuli and at the insertion area on the fovea capitis and stored at -20°C until utilization. Specimens were mounted to a materials testing machine via custom clamps that minimized slippage and the likelihood of failure at the clamp. Force-displacement and stress-strain curves were generated. Ultimate failure load (N), tensile strength (MPa), stiffness (N/mm), and elastic modulus (MPa) were determined. Using a multivariate regression analysis and a subgroup analysis, we tested demographic, degenerative, and radiographic factors as potential associated factors. The ligamentum teres demonstrated an ultimate load to failure of 126 ± 92 N, and the tensile strength was 1 ± 1 MPa. The ligaments exhibited a stiffness of 24 ± 15 N/mm and an elastic modulus of 7 ± 5 MPa. After controlling for potential confounding variables like age, fossa/fovea degeneration, and acetabular/femoral morphologies, we found that female sex was an independent factor for higher tensile strength, stiffness, and elastic modulus. Excessive femoral version was independently associated with lower load to failure (HR 122 [95% CI 47 to 197]) and stiffness (HR 15 [95% CI 2 to 27]). Damage to the acetabular fossa was associated with reduced load to failure (HR -93 [95% CI -159 to -27]). Overall, the ligamentum teres is a relatively weak ligament. Sex, degeneration, and excessive femoral version are influencing factors on strength of the ligamentum teres. The ligamentum teres exhibits lower strength compared with other joint-stabilizing ligaments, which calls into question its overall contribution to hip stability. Young patients undergoing hip-preserving surgery are the population at risk for ligamentum teres lesions. Baseline values for load to failure, tensile strength, elastic modulus, and stiffness are needed to better understand those lesions in this cohort of interest.

A Novel Simulation Model and Training Program for Minimally Invasive Surgery of Hallux Valgus.

Minimally invasive surgery (MIS) for hallux valgus (HV) has gained popularity. However, adopting this technique faces the challenges of a pronounced learning curve. This study aimed to address these challenges by developing and validating an innovative simulation model and training program, targeting enhanced proficiency in HV MIS. A training program and a high-fidelity simulation model for HV MIS were designed based on experts' recommendations. Four foot and ankle surgeons without experience in MIS formed the novice group and took the program that encompassed six-session instructional lessons, hands-on practice on simulated models, and immediate feedback. The program concluded with a cadaveric surgery. Four foot and ankle experienced MIS surgeons formed the expert group and underwent the same procedure with one simulated model. Participants underwent blind assessment, including Objective Structured Assessment of Technical Skills (OSATS), surgical time, and radiograph usage. Expert evaluation of the simulation model indicated high satisfaction with anatomical representation, handling properties, and utility as a training tool. The expert group consistently outperformed novices at the initial assessment across all outcomes, demonstrating OSATS scores of 24 points (range, 23 to 25) versus 15.5 (range, 12 to 17), median surgical time of 22.75 minutes (range, 12 to 27) versus 48.75 minutes (range, 38 to 60), and median radiograph usage of 70 (range, 53 to 102) versus 232.5 (range, 112 to 280). Novices exhibited a significant improvement in OSATS scores from the fifth session onward (P = 0.01), reaching the desired performance of 20 points. Performance at the final training with the simulated model did not differ from cadaveric surgery outcomes for all parameters. This study validated a simulation model and training program, allowing nonexperienced HV MIS foot and ankle surgeons to enhance their surgical proficiency and effectively complete a substantial portion of the learning curve at the fifth session, and this performance was successfully transferred to a cadaver model. III.

Is Ocular Safety in Orthopaedics Overlooked? A Systematic Review of Annual Ocular Radiation Exposure and Protective Measures.

Intraoperative fluoroscopy is increasingly common in orthopaedics, although recent guidelines have reduced the maximum recommended exposure to 20 mSv annually. A systematic review of the literature was conducted to comprehensively assess current adherence to exposure guidelines, identify practice settings at increased risk for exposure, and determine the best practices and personal protective equipment for ocular radiation risk mitigation. In this systematic review we asked: (1) Is the annual amount of eye irradiation received by orthopaedic surgeons below the recommended limit of 20 mSv? (2) What is the effectiveness of leaded glasses in reducing the eye's exposure to radiation? (3) Which imaging setups and operative techniques reduce ocular irradiation? PubMed, Medline, EBSCOhost, and Google Scholar were queried on September 28, 2023, to identify studies assessing intraoperative ocular radiation exposure among orthopaedic surgeons. Studies that measured radiation in or around the eye (such as the bridge of the nose or eyebrows) during orthopaedic procedures were included. Exclusion criteria were duplicate studies, studies that only estimated eye radiation based on the radiation dose recorded at parts of the body distant from the eyes, nonoriginal research, case reports, and articles without full-text English versions available. A total of 393 unique articles were retrieved, and after title, abstract, and full-text screening, 23 dosimetry studies were included, comprising 12 prospective observational studies, 7 phantom models, 1 cadaver model, 2 observational studies, and 1 randomized control trial. Risk of bias was determined via the Methodological Index for Nonrandomized Studies (MINORS) tool. Study quality was generally good to excellent, with noncomparative studies having a mean MINORS score of 14 ± 0 of 16 and comparative studies achieving a mean score of 19 ± 1 of 24, with higher scores representing better study quality. Due to extensive heterogeneity in study design, a meta-analysis was not conducted, with the results rather presented as a narrative summary of key findings. The vast majority of surgeons conducting a variety of orthopaedic and traumatologic procedures were not exposed to a hazardous level of eye irradiation annually, but surgeons who perform a high volume of fluoroscopy-intensive procedures may exceed guidelines. Leaded eyeglasses reduced eye radiation by about 90%, with sport wrap-around glasses offering better shielding than alternatives, although leaded glasses overall were largely underutilized. Positioning mini C-arms in the standard vertical configuration was shown to provide up to a 13-fold decrease in radiation exposure compared with inverted configuration, while standing perpendicular to the fluoroscope further reduced eye irradiation. We found that orthopaedic surgeons who perform a high volume of fluoroscopy-intensive procedures may be at risk of exceeding recommendations on annual radiation exposure, although exposure can be mitigated through various simple strategies. In particular, this analysis found that the use of sport wrap-around leaded glasses, positioning of mini-C arms in the standard vertical configuration, and standing perpendicular to the fluoroscope provide the most effective means of limiting ocular radiation exposure. As ophthalmic radiation exposure presents a potentially important occupational health hazard to orthopaedic surgeons, further investigations of radiation exposure specific to high-volume, fluoroscopy-intensive orthopaedic practices and long-term ophthalmic outcomes will help determine the extent of the potential harm posed by frequent exposure to intraoperative radiation over the span of a career. Level III, therapeutic study.

Comparing cadaveric and 3D-printed laryngeal models in transcutaneous injection laryngoplasty.

There is increasing focus on the development of high-quality simulation models for medical education. Cadaveric models, although considered more realistic, may be difficult to obtain and costly. The advent of three-dimensional (3D) printing has offered a low-cost, reliable, and reproducible alternative. This study sought to compare the utility of 3D-printed to cadaveric models for training in transcutaneous injection laryngoplasty (TIL). A simulation course with a cross-over design was employed. Video laryngoscopes were utilized for both the 3D and cadaveric models to assess the accuracy of injection into the vocal fold. Pre-procedure and post-procedure surveys were administered to evaluate understanding and comfort level on a Likert scale of 1-10. Each model was also rated on a 1-5 Likert scale for self-efficacy, fidelity, and educational value. Pre- and post-survey data were completed by 15 otolaryngology residents and medical students. Mean pre-seminar understanding and comfort level were 3.7 and 2.2, respectively, compared to 6.9 and 5.9 (p < .05) following use of the 3D model and 6.4 and 4.7 (p < .05) following use of the cadaver model. When comparing 3D and cadaveric models, no significant differences were observed regarding self-efficacy, fidelity, and educational value. There was a similar mean increase in understanding and comfort following use of the 3D and cadaveric models. 3D-printing can provide an excellent adjunct to, and eventually a potential replacement for hands-on cadaveric training in medical education, particularly for TIL. Level III.

The relationship between intraosseous catheter tip placement, flow rates, and infusion pressures in a high bone density cadaveric swine (Sus scrofa) model.

Intraosseous (IO) infusion is a life-preserving technique when intravenous access is unobtainable. Successful IO infusion requires sufficiently high flow rates to preserve life but at low enough pressures to avoid complications. However, IO catheter tips are often misplaced, and the relative flow rates and pressures between IO catheter tips placed in medullary, trabecular, and cortical bone are not well described, which has important implications for clinical practice. We developed the Zone Theory of IO Catheter Tip Placement based on bone density and proximity to the venous central sinus and then tested the influence of catheter tip placement locations on flow rates and pressures in a cadaveric swine model. Three cross-trained participants infused 500mL of crystalloid fluid into cadaveric swine humerus and sternum (N=210 trials total) using a push‒pull method with a 60 cm3 syringe. Computed tomography scans were scored by radiologists and categorized as zone 1 (medullary space), zone 2 (trabecular bone), or zone 3 (cortical bone) catheter tip placements. Differences between zones in flow rates, mean pressures, and peak pressures were assessed using analysis of variance and analysis of covariance to account for participant and site differences at the p<0.05 threshold. Zone 1 and zone 2 placements were essentially identical in flow rates, mean pressures, and peak pressures (each p>0.05). Zone 1 and zone 2 placements were significantly higher in flow rates and lower in pressures than zone 3 placements (each p<0.05 or less). Within the limitations of an unpressurized cadaveric swine model, the present findings suggest that IO catheter tip placements need not be perfect to acquire high flow rates at low pressures, only accurate enough to avoid the dense cortical bone of zone 3. Future research using in vivo animal and human models is needed to better define the clinical impact of IO catheter placement on infusion flow rates and pressures.

Contribution of the cadaveric recirculation system in the anatomical study of lymphatic drainage of the ovary: applications in the management of ovarian cancer.

The present knowledge about lymphatic drainage of the ovary is based on carcinological studies, but it has only rarely been studied under physiological conditions. However, it is one of the preferential routes of dissemination in ovarian cancer, and understanding it is therefore vital for optimal carcinological management.Our purpose was to evaluate the feasibility of an innovative technique to study the lymphatic drainage territories of the ovary using a recirculation module on the cadaveric model. We injected patent blue into the cortex of twenty "revascularised" cadaver ovaries with the Simlife recirculation model. We observed the migration of the dye live and described the drainage territories of each ovary. We observed a staining of the lymphatic vessels and migration of the dye in all the subjects, systematically ipsilateral to the injected ovary. We identified a staining of the lumbo-aortic territory in 65% of cases, with a preferential lateral-caval involvement (60%) for the right ovary and lateral-aortic territory (40%) for the left ovary. A common iliac involvement was observed in only 10% of cases. In 57% of cases, the staining of the lumbo-aortic territory was associated with a staining of the suspensory ligament. The pelvic territory was involved in 50% of cases, with an external iliac staining in 25% of cases and internal in 20%. Our study provides for a better understanding of lymphatic drainage of the ovary using a new detection method, and allows the possibility of improving the teaching for operators with a realistic model. Continuation of this work could lead to considering more targeted and thus less morbid lymph node sampling for lymph node staging in early-stage ovarian cancer.