Cadaveric Model Research Articles

A Suture Method for Collateral Ligaments of the Finger Proximal Interphalangeal Joint: A Cadaver Study.

In a cadaveric model, a comparison was made of the strength of a suture method for collateral ligaments (the N method) with that of simple sutures using suture anchors for the repair of collateral ligaments in the proximal interphalangeal joint. We obtained 72 fingers from 18 upper limbs of fresh-frozen cadavers and compared the left and right sides of the same specimens. In experiment 1, we examined the rupture strength and rupture sites of intact collateral ligaments in 24 fingers. In experiment 2, we compared the rupture strength and failure modes of the N method (three locking sutures) with those of simple sutures (S group) on 32 fingers. In experiment 3, we examined the rupture strength and failure modes between the N method with three locking sutures (N3 group) and the N method with two locking sutures (N2 group) on 16 fingers. All the experiments involved mechanical testing by applying lateral stress to the collateral ligaments at a rate of 1 mm/s using testing equipment. In Experiment 1, the mean rupture strength of intact collateral ligaments was 80.6 ± 27.5 N. Proximal tears were the most common rupture sites. In Experiment 2, the mean rupture strength was significantly higher in the N group (46.3 ± 19.2 N) than in the S group (24.1 ± 12.7 N). In the N group, suture breakage occurred more frequently than in the S group, whereas in the S group, there was a higher incidence of suture cut out. In Experiment 3, the N3 and N2 groups exhibited nearly identical rupture strength values. This study showed that the N method had better rupture strength than the simple suture method following finger collateral ligament repair. The outcome provides useful information for informing the choice of suture method in clinical practice.

Evaluation of training models for intraventricular neuroendoscopy.

Structured surgical education has become increasingly important in recent years. Intraventricular neuroendoscopic procedures have been widely established. However, training surgical skills with these techniques is crucial for young residents due to the potential harm to adjacent tissue. Therefore, we evaluated two different training models.Participants in two different international workshops were trained on a prefixed cadaver model and on a living murine intraabdominal model. Crucial neuroendoscopic techniques such as membrane perforation and tissue biopsy were performed. A blinded questionnaire evaluated both models.Sixty-three participants were trained on the animal model. Forty of these were trained on the cadaver model. The training effect was evaluated almost equally, with 8.5/10 for the animal model and 8.9/10 for the cadaver model. The tissue properties were rated higher regarding realism in the animal model, whereas the anatomic realism was rated higher in the cadaver model.The animal model is a valid alternative to cadaver models for teaching endoscopic neurosurgical skills. This model benefits from the simulation of real surgical tissue properties, including bleeding. The low costs and availability of this technique make it more ubiquitous and can help train further generations of neurosurgeons.

Harnessing Foot Mechanics: The Role of Lacing Techniques in Enhancing Comfort and Reducing Injury Risk

Background: Lacing techniques are often viewed as a functional necessity, but recent research has highlighted their role as a customization tool for foot health and comfort. This review synthesizes findings from studies examining the biomechanical effects of different lacing patterns on pressure distribution, tendon loading, and foot mechanics. Methods: We analyzed studies that investigated various lacing techniques, including tightness and patterns. Objective measurements, such as pressure insoles and cadaveric models, were used to quantify the effects. Diverse study populations, including individuals with foot health concerns and athletes, were considered. This study was conducted as a scoping review following the JBI methodology, adhering to the PRISMA-ScR guidelines. Results: The studies collectively reveal that lacing patterns significantly influence dorsal pressure distribution during activities like running. Customized lacing can optimize foot biomechanics, reducing the risk of injuries related to abnormal pressure distribution. A total of 27 records were identified from the initial search. After removing duplicates and screening, four articles were included in the final review. Additionally, certain lacing configurations were found to reduce peak Achilles tendon tension, a crucial finding for injury-prone individuals. Conclusions: Proper lacing techniques are not just a functional aspect but a means to enhance foot health and prevent injuries. Healthcare professionals can provide personalized lacing recommendations to patients, with implications for those with specific foot conditions, athletes, and individuals at risk of injuries. The importance of patient education on the significance of lacing techniques cannot be overstated, emphasizing the need for informed choices when lacing shoes. These findings underscore the multifaceted role of lacing techniques in promoting foot health and well-being.

Evaluation of a novel nerve ablation technique to relieve lower back pain: A cadaveric feasibility pilot study.

Radiofrequency ablation is a treatment for facetogenic low back pain that targets medial branches of lumbar dorsal rami to denervate facet joints. Clinical outcomes vary; optimizing cannula placement to better capture the medial branch may improve clinical outcomes. A novel parasagittal technique was proposed from an anatomical model; this technique was proposed to optimize capture of the medial branch. The anatomical feasibility of the novel technique has not been evaluated. To simulate and evaluate the proposed parasagittal technique in its ability to achieve proper cannula placement, and proximity of uninsulated cannula tips to the medial branches of the dorsal rami in cadaveric specimens. Under fluoroscopic guidance, 14 cannulae were placed using the parasagittal technique targeting the lumbar medial branches of two cadavers. Meticulous dissection was undertaken to assess cannula alignment and measure proximities to target nerves using a digital caliper. The novel parasagittal technique was successfully performed in a cadaveric model in 12/14 attempts. The technique achieved close proximity of cannula tips to medial branches (0.8 ± 1.1 mm). In two instances cannulae were placed unsuccessfully, where one cannula was too far anterior, the other too far retracted. In this cadaveric simulation study, the feasibility of performing the parasagittal technique for lumbar radiofrequency ablation was evaluated. This study suggests the parasagittal technique is a feasible option for lumbar medial branch radiofrequency ablation.

Radiating for Two: Quantifying Radiation Exposure to Pregnant Urologists During Percutaneous Nephrolithotomy.

Current occupational recommendations limit fetal radiation dose to 1 mSv. With increased gender diversity in urology, understanding radiation exposure during pregnancy is crucial. The purpose of this study was to determine surgeon uterine radiation dose during percutaneous nephrolithotomy (PCNL) and compare effectiveness of several radiation reduction strategies in a cadaver model. Two cadavers were used to simulate the surgeon and patient in a PCNL model. An ion chamber was placed behind the surgeon's anterior uterine wall to measure radiation dose. Three radiation reduction methods were compared: pulsed fluoroscopy (1, 4, 8, 15, 30 pps), low-dose (LD) fluoroscopy, and surgeon shielding (none, 0.35, 0.50, 0.70 mm lead equivalents). The average radiation dose/second was recorded for 20 trials per combination. Assuming 5 minutes of fluoroscopy per PCNL, the number of cases required to exceed the fetal occupational limit was determined. Decreasing pulse frequency from 30 to 1 pps reduced dose by 96% (p<0.001). The LD setting decreased dose by 56% (p<0.001). A 0.35 mm lead apron resulted in a 94% dose reduction (p<0.001), and the 0.50 and 0.70 mm lead aprons further reduced dose by 12% and 47%, respectively. At conventional fluoroscopy settings of automatic exposure control and 30 pps, a surgeon could perform 12 PCNLs using no lead or 189 PCNLs using a 0.35 mm lead apron before reaching the 1 mSv limit. In addition to shielding, employing 1 pps with LD further decreased radiation exposure, allowing over 6000 cases to be performed with <1 mSv uterine radiation exposure. Within the limitations of this cadaver study, these data support that high volume pregnant surgeons employing active radiation reduction techniques such as pulsed, LD fluoroscopy and appropriate shielding can maintain surgical volume with relatively low risk. Fetal dosimeter use with monthly monitoring is still encouraged to confirm safety throughout pregnancy.

Evaluation of Injectate Distribution of the Middle Mental Nerve Block Within the Mandibular Canal in a Cadaveric Canine Model.

Awareness among veterinarians has increased regarding the need for comprehensive pain relief, but many companion animal veterinarians do not administer regional analgesia pre-emptively during dental procedures. The middle mental nerve (MMN) block desensitizes the ipsilateral mandibular incisor and canine teeth as well as soft tissues rostral to the delivery site. There is little published information on the efficacy of the MMN block in dogs. The objective of this study was to determine injectate distribution within the mandibular canal using a radiopaque contrast media/methylene blue solution. Half a milliliter of solution was injected within the opening of the middle mental foramen using a standard hypodermic syringe and a 25G x 25 mm needle. The course of the injectate was traced both via computed tomography (CT) and, in some cadavers, gross dissection. Post-treatment CT revealed that in 90% of the cases, the contrast diffused at least as far caudally as the mesial root of the third premolar tooth. The injectate was not identified within the canal of 5% of cadaveric mandibles examined. Although the solution used diffused caudally within the mandibular canal when injected using recommended clinical techniques, this may not completely represent the extent of clinical effects experienced in live patients. This technique also confirmed that the needle does not need to be advanced into the mandibular canal to achieve adequate diffusion to at least the mesial root of the third premolar tooth.

Comparison of three approaches for accessory lung lobectomy in the canine cadaveric model: Intercostal thoracotomy, median sternotomy, and a transdiaphragmatic approach combined with caudal median sternotomy.

To describe a combined transdiaphragmatic and caudal median sternotomy (TDCM) approach to the accessory lung lobe and to compare its accessibility with intercostal thoracotomy (ICT) and median sternotomy (MS). Cadaveric study. Twelve canine cadavers. Cadavers underwent an accessory lung lobectomy using an articulating EndoGIA stapler via randomly assigned approach: ICT (n = 4), MS (n = 4) or TDCM (n = 4). The percentage of accessory lung tissue removed was measured in surface area and weight. Exposure was measured as area of cavitary or bicavitary exposure at maximal retraction, by tracing a line around the circumference of the exposed cavity using an imaging software. Staple line leak pressures were evaluated to 40 cmH2O. The average area of exposure was larger in the TDCM approach (TDCM = 193.5 cm2, MS = 106.5 cm2, ICT = 73.5 cm2); (p = .01). Two of four ICT staple lines leaked at 40 cmH2O or lower, and 1/4 MS resulted in iatrogenic damage to an adjacent lobe. There was no difference in the percentage of the lobe excised by weight or surface area between groups. The transdiaphragmatic and caudal median sternotomy approach provided greater exposure, although the percentage of the lobe excised and the surgical time did not differ between approaches. All three approaches allowed for adequate excision of the accessory lung lobe (ALL) with similar surgical times; however, the TDCM approach provided a greater area of exposure, which could increase accessibility to the ALL.

A cadaveric study showing the OLIF corridor dimensions after retraction of the abdominal great arteries and psoas major.

The aim of this study is to assess the oblique lateral interbody fusion (OLIF) corridor dimensions when the abdominal great arteries (the abdominal aorta or common iliac arteries) and psoas major are retracted. Twenty embalmed cadaveric specimens were dissected. The widths of the OLIF operative corridor at L1-2, L2-3, L3-4, and L4-5 were measured with the psoas major and abdominal great arteries in static state, with psoas retraction, and with mild retraction of the abdominal great arteries. The retractable distances of the psoas major and the abdominal great arteries at each lumbar segment were compared. In the static state, the operative corridor gradually narrowed from L1-2 to L4-5, but there was no significant difference in its width between segments (p > 0.05). There was no significant difference in the corridor width between segments after retraction of the psoas major or the abdominal great arteries (p > 0.05). However, retraction of either the psoas major or the abdominal great arteries made the corridor at the L1-5 segments significantly wider than those in the static state (p < 0.05), particularly at L4-5, and the retractable distance of the psoas major was significantly greater (p < 0.05). The cadaveric model demonstrated the use of abdominal great arteries retraction in principle. The OLIF operative corridor could be widened to some extent by retracting the abdominal great arteries, and widened further by retracting the psoas major.

A 3D-Printed, High-Fidelity Pelvis Training Model: Cookbook Instructions and First Experience.

Background: Since laparoscopic surgery became the gold standard for colorectal procedures, specific skills are required to achieve good outcomes. The best way to acquire basic and advanced skills and reach the learning curve plateau is by using dedicated simulators: box-trainers, video-trainers and virtual reality simulators. Laparoscopic skills training outside the operating room is cost-beneficial, faster and safer, and does not harm the patient. When compared to box-trainers, virtual reality simulators and cadaver models have no additional benefits. Several laparoscopic trainers available on the market as well as homemade box and video-trainers, most of them using plastic boxes and standard webcams, were described in the literature. The majority of them involve training on a flat surface without any anatomical environment. In addition to their demonstrated benefits, box-trainers which add anatomic details can improve the training quality and skills development of surgeons. Methods: We created a 3D-printed anatomic pelvi-trainer which offers a real-size narrow pelvic space environment for training. The model was created starting with a CT-scan performed on a female pelvis from the Anatomy Museum (Cluj-Napoca University of Medicine and Pharmacy, Romania), using Invesalius 3 software (Centro de Tecnologia da informação Renato Archer CTI, InVesalius open-source software, Campinas, Brazil) for segmentation, Fusion 360 with Netfabb software (Autodesk software company, Fusion 360 with Netfabb, San Francisco, CA, USA) for 3D modeling and a FDM technology 3D printer (Stratasys 3D printing company, Fortus 380mc 3D printer, Minneapolis, MN, USA). In addition, a metal mold for casting silicone valves was made for camera and endoscopic instruments ports. The trainer was tested and compared using a laparoscopic camera, a standard full HD webcam and "V-Box" (INTECH-Innovative Training Technologies, Milano, Italia), a dedicated hard paper box. The pelvi-trainer was tested by 33 surgeons with different qualifications and expertise. Results: We made a complete box-trainer with a versatile 3D-printed pelvi-trainer inside, designed for a wide range of basic and advanced laparoscopic skills training in the narrow pelvic space. We assessed the feedback of 33 surgeons regarding their experience using the anatomic 3D-printed pelvi-trainer for laparoscopic surgery training in the narrow pelvic space. Each surgeon tested the pelvi-trainer in three different setups: using a laparoscopic camera, using a webcam connected to a laptop and a "V-BOX" hard paper box. In the experiments that were performed, each participant completed a questionnaire regarding his/her experience using the pelvi-trainer. The results were positive, validating the device as a valid tool for training. Conclusions: We validated the anatomic pelvi-trainer designed by our team as a valuable alternative for basic and advanced laparoscopic surgery training outside the operating room for pelvic organs procedures, proving that it supports a much faster learning curve for colorectal procedures without harming the patients.

Midclavicle block: An anatomical study.

Recent studies indicate that clavipectoral fascia plane block (CPB) efficacy may stem from injectate distribution to the anterosuperior clavicular periosteum. We conducted an anatomical study combining the CPB with injection within the subclavius muscle. Our hypothesis was that the anaesthetic injectate would fully cover both the anterosuperior and posteroinferior surfaces of the clavicular periosteum in the midclavicular region. Observational human cadaver study. Laboratory of Surgical Neuroanatomy, Unit of Anatomy and Human Embryology of the Faculty of Medicine and Health Sciences, University of Barcelona. Five fresh human cadavers. The cadavers received both a CPB and subclavius muscle injections under ultrasound guidance in 10 clavicular regions. After the procedures on the cadaveric models, an anatomical dissection by planes was performed to evaluate the distribution pattern of methylene blue on the clavicular periosteum. A probabilistic map of the colour spectrum and staining temperature on the clavicular surfaces was generated. Methylene blue stained 37 ± 16% of the anterosuperior surface and 23 ± 13% of the posteroinferior surface of the clavicular periosteum, particularly in the middle third of each surface. Although the staining did not achieve complete circumferential coverage or perfect alignment between the surfaces, the areas exhibited a close relationship, indicating significant distribution and relevant coverage. Our anatomical study demonstrates that the midclavicular block achieves effective distribution around the middle third of the clavicle, although complete circumferential anaesthesia of the clavicular periosteum was not achieved. Although this block may provide periosteal and bone anaesthesia, it does not address other sources of pain, such as muscle spasms and skin components. Additional clinical studies are needed to evaluate the overall efficacy of this dual block technique for clavicle surgery.

Comparative analysis of mechanical and drilling properties: Human skull vs. 3D-printed replicas for neurosurgical training

Neurosurgery is one of the most difficult surgical disciplines, making neurosurgical simulation crucial for learners. 3D printing is increasingly used for this simulation due to its accessibility and cost-effectiveness compared to conventional methods. Previous studies have qualitatively evaluated the efficacy of 3D printing models for burr hole and craniotomy simulation using surgeon feedback. This study quantitatively evaluates the mechanical properties of human skulls and compares them with 3D-printed skulls to identify the necessary materials and technologies for accurate replication in neurosurgical training. Vickers hardness, compression, and drilling simulation tests were conducted on human cadaveric skulls and 3D-printed models manufactured using Fused Filament Fabrication (FFF), Stereolithography (SLA), and Material Jetting (MJ) technologies. Uniaxial force during a simulated burr hole procedure was measured as drilling progressed through the outer table (OT), diploë and inner table (IT) of the skull. The results showed that different 3D printing technologies and materials have qualities corresponding to each of the three layers of the human skull. For instance, the White Resin 40 model was the closest match to the OT of human skull, exhibiting the lowest mean difference of drilling modulus of 1.98. The OT of the human skull had a Vickers hardness of 38.6 ± 5 HV0.05. The closest 3D-printed models were SLA White at 16.6 ± 0.3 HV0.05 and Rigid 10K at 65.7 ± 3 HV0.05. In terms of mechanical properties, the human skull demonstrated a compression modulus that closely matched the SkullSTN 2, PC 60, PEEK 40, and PEEK 60, with differences of less than 0.1 GPa. These findings demonstrate the effectiveness of drilling simulation tests in evaluating various materials and infills to refine models before neurosurgeon evaluation, enabling the identification of an optimal 3D-printed training model for simulating burr hole procedures.

Hinotori™ robotic esophagectomy: a feasibility cadaver study.

This preclinical feasibility study investigates the potential of utilizing the hinotori™ robot system for esophagectomy. In three human cadaver models, the esophagus was successfully mobilized and resected using the hinotori™ system, with a mean thoracic procedure time of 57minutes. The system allowed for precise dissection and radical lymphadenectomy without arm collision, attributed to its versatile design and docking-free trocars. Standard robot-specific patient positioning, including a 35° left lateral inclination, and trocar placement in a posterior axillary line configuration were employed. Notably, trocars suitable for both laparoscopy and the hinotori™ robot were utilized, providing flexibility in trocar selection. Unique features, such as the ergonomic console and pointer-based pivot point identification system, contributed to procedural success. While these findings highlight the promising potential of the hinotori™ system in advancing esophageal surgery, further clinical studies are warranted to validate its reproducibility and clinical utility. Additionally, enhancements to the pivot point identification system and evaluation of the arm base's features may further optimize surgical outcomes.

Evaluating the efficacy of a cost-effective, fully three-dimensional-printed vertebra model for endoscopic spine surgery training for neurosurgical residents.

A fused deposition modeling three-dimensional (3D)-printed model of the L4-5 vertebra for lumbar discectomy was designed. The model included separately printed dura mater, spinal cord, ligamentum flavum, intervertebral disc (from thermoplastic polyurethane), and bony structures (from polylactic acid), and the material cost approximately US$ 1 per model. A simple plumbing endoscope was used for visualization. Dura mater injury was assessed by painting two layers on the dura mater, which peeled off with trauma. Endoscopic spine surgery is a subject of high interest in neurosurgery given its minimally invasive nature; however, it has a steep learning curve. This study evaluated the effectiveness of a cost-efficient 3D-printed model when teaching this technique to neurosurgery residents. Only a few studies have investigated the efficacy of such a model. Eight residents with >2 years of training participated. Residents performed the procedure bilaterally and twice at 1-week intervals. From the 32 surgeries, four were excluded because of facet removal (as it widened the surgical corridor), leaving 28 surgeries for analysis. Initial surgeries demonstrated a mean operation time of 21 minutes 18 seconds (standard deviation [SD], 2 minutes 32 seconds), which improved to a mean of 6 minutes 45 seconds (SD, 37 seconds) in the fourth surgery (F(3, 17)=19.18, p <0.0001), demonstrating a significant reduction in surgical time over successive surgeries. The median area with the paint removed decreased, from 161.80 (85.55-217.83) to 95.13 mm2 (12.62-160.54), (F(2.072, Inf)=2.04, p =0.128); however, this was not significant. Resident feedback indicated high satisfaction with the educational value of the model. The developed fully 3D-printed model provides a viable and scalable option for neurosurgical training programs, enhancing the learning experience while maintaining low costs. This model may be an excellent stepping stone for learning lumbar spine endoscopy, acclimating to the two-dimensional view, progressing to cadaver models, and, eventually, independent surgery.

A human cadaveric model for venous air embolism detection tool development.

A human cadaveric model combining standard lung protective mechanical ventilation and modified cardiac bypass techniques was developed to allow investigation into automated modes of detection of venous air emboli (VAE) prior to in vivo human or animal investigations. In this study, in order to create an artificial cardiopulmonary circuit in a cadaver that could mimic VAE physiology, the direction of flow was reversed from conventional cardiac bypass. Normal saline was circulated in isolation through the heart and lungs as opposed to the peripheral organs by placing the venous cannula into the aorta and the arterial cannula into the inferior vena cava with selective ligation of other vessels. Mechanical ventilation and this reversed cardiac bypass scheme allowed preliminary detection of VAE independently but not in concert in our current simulation scheme due to pulmonary edema in the cadaver. A limited dissection approach was used initially followed by a radical exposure of the great vessels, and both proved feasible in terms of air signal detection. We used electrical impendence as a preliminary tool to validate detection in this cadaveric model however we theorize that it would work for echocardiographic, intravenous ultrasound or other novel modalities as well. A cadaveric model allows monitoring technology development with reduced use of animal and conventional human testing.

Use of a Porcine Cadaver Model as a Human Surrogate for Behind Armor Blunt Trauma

Abstract Current body armor design evaluation is based on legacy backface deformation criteria for protection, despite limited medical basis. This uniform protection approach, which does not account for anatomical and physiological variability within the torso, may result in heavy armors that limit Warfighter mobility. To optimize armor design, live animal experimentation must be conducted to assess regional injury tolerances; however, the animal and human must first be compared to determine the animal model's viability as a surrogate for thoracoabdominal behind armor blunt trauma (BABT) response. Here, 74 BABT impacts were conducted using ten mid-sized male post-mortem human subjects (PMHS) and ten 40-kg porcine cadavers in matched testing conditions over the lungs, liver, and sternum. Injury risk functions were generated from experimental data and compared across surrogates at each body region. The PMHS and 40-kg porcine cadaver correlated well for chest wall injuries in the lung region, and similarities were noted in high-severity impacts to the liver. Further, assessment of the backface intrusion injury risk function showed regional tolerance differences between anatomical regions, highlighting the need for separate region-specific design criteria. These results indicate that the 40-kg porcine cadaver was an appropriate torso surrogate for certain PMHS regions, such as the ribcage overlaying the lungs and the unprotected liver, in BABT conditions. As this study used cadaveric tissue, future studies should investigate the physiological components of BABT-induced injury in a live animal model, focusing on quantifying regional injury tolerances toward armor design optimization.

Assessment of Surgical Competences for Neck Dissection and Total Laryngectomy on Revascularized Cadaver Models: Onco-Neck-Score and Onco-Larynx-Score.

In surgical simulation, evaluation tools are necessary to allow the overall and specific level of each gesture to be assessed for learners, to allow active feedback and follow-up. The aim of this study was to create and validate a scale for the assessment of competences for neck dissection (ND) and total laryngectomy (TL) in head and neck surgical oncology simulation specific for revascularized cadavers' models. Two independent scales were created for ND and TL based on a two-round Delphi method. The scales were used during ND and TL simulation sessions on SimLife® (Symedis, Poitiers, France) model. Surgical steps were scored by 2 independent observers. To assess its ease of use, a questionnaire was answered by senior surgeons (SS) at the end of the sessions. Fifteen items were included in the final version for ND scale and 20 for TL scale. The results of 14 lateral ND and 8TL were included. The mean score was higher for SS (69 ± 6.4; 87.5 ± 8.5) than for residents (36.5 ± 11; 57.5 ± 13.2) for ND (P = 0.0006) and TL (P = 0.028) respectively. Six SS strongly agreed that this tool had a positive impact on resident training with stepwise feedback and accurately represented their competences. We developed a pedagogic tool built to assess surgical competence for head and neck surgical oncology on revascularized cadaver models. This tool has a good construct validity thanks to the expert reviewing with Delphi method and appears to have fine acceptability by the SS.

Image quality of photon-counting detector CT for visualization of maxillofacial anatomy in comparison with energy-integrating detector CT and intraoperative C-arm CBCT

BackgroundAccurate diagnostic imaging is crucial for managing facial fractures, which are a common global occurrence. This study aimed to compare the image quality of Photon Counting Detector CT (PCD-CT) with state-of-the-art Energy Integrating Detector CT (EID-CT) and intraoperative C-arm CBCT (CBCT) in visualizing maxillofacial anatomy using a cadaveric sheep head model. MethodsThree fresh sheep heads were used, with surgical interventions simulating metal implants in two of them. The specimens were imaged using PCD-CT, EID-CT, and CBCT, following which quantitative assessments of signal-to-noise ratio, sharpness, and artifacts were conducted. A visual grading study was performed by six observers, using criteria focusing on the mandible, orbit, and soft tissues. Statistical analyses included Friedman tests for comparing modalities and Kendall’s W and Gwet’s AC1 for assessing inter- and intrarater agreement. ResultsPCD-CT demonstrated a significantly higher signal-to-noise ratio (p = 0.03) and bone sharpness (p < 0.001) compared to CBCT. In visual grading, PCD-CT outperformed CBCT, but not EID-CT, particularly in delineating mandibular and orbital structures. EID-CT and PCD-CT showed slightly more severe hypodense artifacts (p = 0.01) but were comparable in streak artifact presentation. The interrater and intrarater agreements indicated consistent evaluations across and within observers. ConclusionPCD-CT exhibits superior image quality over CBCT in key parameters essential for maxillofacial imaging, while no apparent improvement was shown compared to state-of-the-art EID-CT. PCD-CT offers enhanced visualization of critical anatomical structures, suggesting its potential as a preferred modality in managing maxillofacial trauma. The findings in this study align with limited existing research on PCD-CT, underscoring its promise for advanced diagnostic imaging in maxillofacial applications.

Biomechanical Changes to the Hindfoot After Zadek Osteotomy.

Insertional Achilles tendinopathy (IAT) is a common source of heel pain in active adults and athletes. The Zadek osteotomy (ZO) is a calcaneal dorsal closing wedge osteotomy that has demonstrated clinical success as a treatment for IAT, purported to favorably improve tendon mechanics, decrease impingement, and decrease pressure within the retrocalcaneal bursa. The present study aims to evaluate the biomechanical effects of ZO on Achilles strain, position of the Haglund prominence relative to the Achilles insertion, and retrocalcaneal pressure. The ZO was performed on 10 fresh-frozen foot and ankle mid tibia-fibula cadaveric specimens. An osteotomy was performed using a 1-cm dorsal closing wedge procedure secured with a 7.0 mm cannulated screw. Point pressure sensor catheters and differential variable reluctance transducers were used to measure the retrocalcaneal pressure and Achilles strain, respectively, pre- and postosteotomy. Paired t-tests were utilized to detect statistical differences (P < .05). After the ZO, the Haglund prominence was translated 9.9 mm anteriorly with respect to the insertion of the Achilles (P < .05) and the Achilles tendon insertion was translated 3.4 mm proximally (P < .05). The ratio of calcaneal length to greater tuberosity length, the X/Y ratio, increased from 2.56 to 3.52 with the osteotomy (P < .05). At maximum dorsiflexion, retrocalcaneal pressure decreased from 117 to 66 mm Hg (44%, P = .018). The Achilles strain changed from 0.00362 to 0.00436 in the anterior fibers (P = .484) and changed from 0.00467 to 0.00283 in the posterior fibers (P = .088). Biomechanical testing in a cadaveric model demonstrates that the ZO decreased retrocalcaneal pressure, shifted the Achilles tendon insertion proximally, increased the X/Y ratio of the calcaneus, and did not significantly change the strain of the Achilles tendon. Despite the clinical success demonstrated in recent literature, there are no biomechanical studies describing the effect of the ZO on the biomechanics of the hindfoot, and the mechanism of symptom relief of the ZO for IAT is not well understood. The present study measures two potential ZO effects relative to Haglund prominence by measuring retrocalcaneal pressure and displacement of the Achilles tendon with respect to the Haglund prominence, and measures one ZO effect relative to calcification of the tendon by measuring the Achilles tendon strain.

Enhanced stability of the distal radioulnar joint with double suture button construct: a cadaveric study

BackgroundDistal radioulnar joint (DRUJ) instability is a common post-traumatic complication, often leading to chronic pain and dysfunction. Current reconstructive techniques, such as the single suture button construct, offer suboptimal stabilization in certain motions. This study aimed to evaluate whether a double suture button construct provides greater stability than the single construct in a cadaver model of DRUJ instability. We hypothesized that the double suture button construct would more effectively minimize dorsal translation of the radius relative to the ulna.MethodsWe used nine freshly frozen human cadaver upper extremities, destabilized the DRUJ, and then reconstructed the joint using three different suture button constructs: single transverse, double (transverse + oblique), and single oblique. The specimens were secured in a custom-designed testing apparatus to measure dorsal translation of the radius. The study proceeded in five stages: stable DRUJ, unstable DRUJ, and reconstruction using a single transverse, double (transverse + oblique), and single oblique suture button construct. Dorsal translation was measured at neutral, 45° pronation, and 45° supination. Statistical comparisons of mean values were conducted for each stage.ResultsReconstruction with the transverse, transverse plus oblique, and oblique suture button constructs resulted in statistically significant reductions in dorsal translation compared to the unstable DRUJ (p < 0.001 for all). The double-suture button construct significantly minimized dorsal translation in all positions, restoring stability comparable to a stable DRUJ: neutral (p = 1.000), pronation (p = 0.963), and supination (p = 1.000). In contrast, single constructs failed to fully restore stability in pronation and supination.ConclusionThe double suture button construct provides significantly greater stabilization of the DRUJ compared to the single construct. These findings suggest that the double construct could be a more effective option for treating DRUJ instability, particularly in restoring normal joint function during various motions. Further research is warranted to confirm these results in clinical settings.

Radiological and biomechanical evaluation of the ulnar nerve after the percutaneous application of the medial K-wire in the extended position on supracondylar humerus fractures: Does the postoperative long arm splint position matter?

Our study aimed to evaluate and compare the changes in ulnar nerve tension and strain at different elbow positions radiologically and mechanically before and after applying the medial K-wire on the supracondylar humerus fracture cadaver model. We used ten fresh frozen cadaver upper extremity specimens to measure strain and tension on the ulnar nerve in 3 different elbow positions: elbow full extension, elbow flexion-forearm supination, and elbow flexion-forearm pronation. We employed Shear wave elastography (Siemens Acuson S3000 USG, 9L4 linear probe) and a microstrain gauge (Microstrain, Inc., Burlington) to obtain our measurements. Minimum, maximum and mean stress and strain values on the nerve and its surroundings were measured and compared statistically. The mean values of elbows with full extension are statistically lower than those in elbows with 90° flexion-forearm supination and those with 90° flexion-forearm pronation positions. Statistical evaluations were performed between all of the groups. Elbow 90° flexion-forearm pronation, both minimum and maximum and mean values were statistically higher in the group, including the specimens with Kirschner applied. The mean values in the elbow full extension and elbow 90° flexion-forearm supination positions were statistically similar in the specimens with and without the K-wire applied. Despite the numerous techniques described in the literature, there is no absolute technical method to prevent ulnar nerve damage. K-wire application to the medial epicondyle with the elbow in a slightly extended position is a technique that can be applied to reduce the risk of ulnar nerve paralysis. However, it has been reported that ulnar nerve damage can be observed in cases where a splint is placed in the 90° flexion position. We hypothesize that the position of the elbow joint in the postoperative period may contribute to ulnar nerve paralysis due to soft tissue tension and strain and as a result of changing the balance of the surrounding tissues. Our findings suggest that the long arm splint applied in elbow 90° flexion and forearm pronation position should not be preferred in the postoperative period. The maximum strain values obtained in the elbow full extension were lower, suggesting that it would be appropriate to stabilize the elbow in the extension position as much as possible postoperatively. Level of evidence: Level V.