For centuries cadaveric dissection has been a cornerstone of medical anatomy education. However, time and financial limitations in modern, compressed medical curricula, coupled with the abundance of ...alternate modalities, have raised questions about the role of dissection. This study was designed to explore student perceptions of the efficacy of a dissection program for learning musculoskeletal anatomy, and possible adaptations for appropriate inclusion of dissection in the modern medical curricula. A paper‐based questionnaire was used to collect data from 174 medical students after completion of cadaveric dissections. Data were analyzed using both quantitative and qualitative methods. Students strongly believed that cadaver‐based learning is essential to anatomy education and modern teaching modalities only complement this. Moreover, most students reported that dissection provided an additional, immersive learning experience that facilitated active learning and helped in developing manual competencies. Students with previous dissection experience or an interest in anatomy‐related specialties were significantly more likely to attend dissection sessions. Students found that the procedural dissection components enhanced the knowledge of applied anatomy and is beneficial for the development of clinical skills. They welcomed the idea of implementing more procedure‐based dissections alongside lectures and prosections‐based practical (PBP) sessions. Cadaveric dissection plays an integral role in medical anatomy education. Time restraints and an increased focus on clinical significance, however, demand carefully considered adaptations of existing dissection protocols. The introduction of procedure‐based dissection offers an innovative, highly engaging and clinically relevant package that would amalgamate skills essential to medical practice while retaining the benefits that have allowed dissection to stand the test of time.
The acromioclavicular (AC) and coracoclavicular (CC) ligaments are important stabilizers of the AC joint. We hypothesized that AC and trapezoid ligament injuries induce AC joint instability and that ...the clavicle can override the acromion on cross-body adduction view even in the absence of conoid ligament injury. Accordingly, we investigated how sectioning the AC and CC ligaments contribute to AC joint instability in the cross-body adduction position.
Six fresh-frozen cadaveric shoulders were used in this study, comprising five male and one female specimen, with a mean age of 68.7 (range, 51-87) years. The left side of the trunk and upper limb, and the cervical and thoracic vertebrae and sternum were firmly fixed with an external fixator. The displacement of the distal end of the clavicle relative to the acromion was measured using an electromagnetic tracking device. We simulated AC joint dislocation by the sequential resection of the AC ligament, AC joint capsule, and CC ligaments in the following order of stages. Stage 0: Intact AC and CC ligaments and acromioclavicular joint capsule; stage 1: Completely sectioned AC ligament, capsule and joint disc; stage 2: Sectioned trapezoid ligament; and stage 3: Sectioned conoid ligament. The superior clavicle displacement related to the acromion was measured in the horizontal adduction position, and clavicle overriding on the acromion was assessed radiologically at each stage. Data were analyzed using a one-way analysis of variance and post-hoc tests.
Superior displacement was 0.3 mm at stage 1, 6.5 mm at stage 2, and 10.7 mm at stage 3. On the cross-body adduction view, there was no distal clavicle overriding at stages 0 and 1, and distal clavicle overriding was observed in five cases (5/6: 83%) at stage 2 and in six cases (6/6: 100%) at stage 3.
We found that AC and trapezoid ligament sectioning induced AC joint instability and that the clavicle could override the acromion on cross-body adduction view regardless of conoid ligament sectioning. The traumatic sections of the AC and trapezoid ligament may lead to high grade AC joint instability, and the distal clavicle may subsequently override the acromion.
The aim of the study was to use cadaveric models to assess the effect of loading the forearm muscles in different forearm rotations, with or without disruption to the stabilizing components, on the ...intra-articular pressure of the distal radioulnar joint (DRUJ).
Ten forearms with no severe osteoarthritis or injury to the DRUJ stabilizers were used. They were placed in a vertical support, and pressure sensors measured pressure within the DRUJ in 5 forearm rotations (neutral, pronation, supination, extension, and flexion) under the following 6 conditions: 1) no loading; 2) loading (at 1/5 of the load per cross-sectional area) with no disruption; 3) loading with disruption of the triangular fibrocartilage complex (TFCC); 4) loading with disruption of the TFCC and ulnar ligaments (ULs); 5) loading with disruption of the TFCC, ULs and interosseous membrane (IM); and 6) loading with disruption of the TFCC, ULs, IM, and pronator quadratus (PQ).
Under the no disruption-no load, no disruption-loaded, and disrupted TFCC conditions, the highest intra-articular pressures were recorded in supination. Compared with the no-load condition, pressure was greater in the no disruption-loaded condition with a mean difference (MD) of 1.57 kg/cm
in a neutral position. In flexion, pressure was greater with a disrupted TFCC (MD, 4.3 kg/cm
). In supination, pressure was only greater with a disrupted TFCC (MD, 3.3 kg/cm
), and pressure decreased in the other disruption conditions. The pressures recorded did not differ from the no disruption-no load condition in pronation or extension.
Pressures within the DRUJ changed with forearm rotations. In the no disruption-no load, no disruption-loaded, and disrupted TFCC conditions, intra-articular pressure was highest in supination. In flexion and supination with load and disruption of stabilizers, intra-articular pressure only increased significantly in the disrupted TFCC condition compared with no load.
Based on our findings, exercises in supination should be avoided during the first phase of rehabilitation of TFCC injuries given the increased pressure on the DRUJ.
The primary objective of this cadaver study was to assess the feasibility of a novel custom helical distraction system and a patient-specific antral maxillary distractor. The study involved two fresh ...cadaver heads and followed a systematic procedure. First, virtual planning was conducted for an asymmetric maxillomandibular advancement. Custom patient-specific hardware was then fabricated to enable sequential mandibular advancement and gradual maxillary distraction. The mandibular lengthening procedures were found to be highly accurate, with only minor deviations from the planned results. In terms of maxillary distraction, the patient-specific antral distractors demonstrated favorable outcomes, with two noteworthy exceptions. Ideal forward maxillary advancement was short by a modest 2–3 mm in both cadavers. Additionally, cadaver 2 exhibited an unplanned pitch malrotation. However, an excellent occlusion was achieved in cadaver 1 and an acceptable anterior occlusion in cadaver 2, albeit with bilateral posterior open bites that could be readily corrected with interdental elastics in a clinical setting. This cadaver model study provides compelling evidence for the feasibility of patient-specific antral helical distractors, highlighting their potential to yield positive outcomes. Importantly, the study results suggest that patient-specific antral distractors may offer superior results compared to the current standard of linear distractors.
Background
The authors’ group has previously described successful transanal rectosigmoid resection via natural orifice translumenal endoscopic surgery (NOTES) in both porcine and cadaveric models ...using the transanal endoscopic microsurgery platform. This report describes the largest cadaveric series to date as optimization of this approach for clinical application continues.
Methods
Between December 2008 and September 2011, NOTES transanal rectosigmoid resection with total mesorectal excision (TME) was successfully performed in 32 fresh human cadavers using transanal dissection alone (
n
= 19), with transgastric endoscopic assistance (
n
= 5), or with laparoscopic assistance (
n
= 8). The variables recorded were gender, body mass index (BMI), operative time, length of the mobilized specimen, integrity of the mesorectum and the resected specimen, and complications. Univariate statistical analysis was performed.
Results
Of the 32 cadavers, 22 were male with a mean BMI of 24 kg/m
2
(range 16.3–37 kg/m
2
). The mean operative time was 5.1 h (range 3–8 h), and the mean specimen length was 53 cm (range 15–91.5 cm). After the first five cadavers, specimen length significantly improved, and a trend toward decreased operative time was demonstrated. The mesorectum was intact in 100 % of the specimens. In nine cadavers, endoscopic dissection was complicated by organ injury. Evaluation by the operative approach demonstrated a significantly longer specimen with laparoscopic assistance (67.7 cm) than with transgastric assistance (45.4 cm) or transanal dissection alone (49.2 cm) (
p
= 0.013). Comparison of the technique used for inferior mesenteric pedicle division demonstrated both significantly decreased operative time (4.8 vs 6 h;
p
= 0.024) and increased specimen length (57.7 vs 39.6 cm;
p
= 0.025) when a stapler was used in lieu of a bipolar cautery device.
Conclusion
Transanal NOTES rectosigmoid resection with TME is feasible and demonstrates improvement in specimen length and operative time with experience. Transitioning to clinical application requires laparoscopic assistance to overcome limitations related to NOTES instrumentation, as well as procedural training with fresh human cadavers.
Hypothesis and background The purpose of this study was to compare the accuracy of patient-specific guides for total shoulder arthroplasty (TSA) with traditional instrumentation in arthritic cadaver ...shoulders. We hypothesized that the patient-specific guides would place components more accurately than standard instrumentation. Materials and methods Seventy cadaver shoulders with radiographically confirmed arthritis were randomized in equal groups to 5 surgeons of varying experience levels who were not involved in development of the patient-specific guidance system. Specimens were then randomized to patient-specific guides based off of computed tomography scanning, standard instrumentation, and anatomic TSA or reverse TSA. Variances in version or inclination of more than 10° and more than 4 mm in starting point were considered indications of significant component malposition. Results TSA glenoid components placed with patient-specific guides averaged 5° of deviation from the intended position in version and 3° in inclination; those with standard instrumentation averaged 8° of deviation in version and 7° in inclination. These differences were significant for version ( P = .04) and inclination ( P = .01). Multivariate analysis of variance to compare the overall accuracy for the entire cohort (TSA and reverse TSA) revealed patient-specific guides to be significantly more accurate ( P = .01) for the combined vectors of version and inclination. Patient-specific guides also had fewer instances of significant component malposition than standard instrumentation did. Conclusion Patient-specific targeting guides were more accurate than traditional instrumentation and had fewer instances of component malposition for glenoid component placement in this multi-surgeon cadaver study of arthritic shoulders. Long-term clinical studies are needed to determine if these improvements produce improved functional outcomes.
Summary
Although different injection locations for retrolaminar and erector spinae plane blocks have been described, the two procedures have a similar anatomical basis. In this cadaveric study we ...compared anatomical spread of dye in the thoracic region following these two procedures. Following randomisation, 10 retrolaminar blocks and 10 erector spinae plane blocks were performed on the left or right sides of 10 unembalmed cadavers. For each block, 20 ml of dye solution was injected at the T5 level. The back regions were dissected and the involvement of the thoracic spinal nerve was also investigated. Twenty blocks were successfully completed. A consistent vertical spread, with deep staining between the posterior surface of the vertebral laminae and the overlaying transversospinalis muscle was observed in all retrolaminar blocks. Moreover, most retrolaminar blocks were predominantly associated with fascial spreading in the intrinsic back muscles. With an erector spinae plane block, dye spread in a more lateral pattern than with retrolaminar block, and fascial spreading in the back muscles was also observed. The number of stained thoracic spinal nerves was greater with erector spinae plane blocks than with retrolaminar blocks; median 2.0 and 3.5, respectively. Regardless of technique, the main route of dye spread was through the superior costotransverse ligament to the ipsilateral paravertebral space. Although erector spinae plane blocks were associated with a slightly larger number of stained thoracic spinal nerves than retrolaminar blocks, both techniques were consistently associated with posterior spread of dye and with limited spread to the paravertebral space.
Pulvertaft tendon repair is a strong suture technique; however, proper tendon tension is impaired by repair site elongation. Therefore, methods to reduce postoperative elongation are warranted. This ...study aimed to determine the effects of additional core sutures during Pulvertaft tendon repair on repair site elongation and rupture strength.
A total of 48 finger extensor tendons were harvested from fresh-frozen cadavers, and tendons with similar diameters were paired. The 24 pairs of tendons were divided into the following 4 groups: group I, 3 interlaced weaves only; group II, 3 interlaced weaves and 2 core suture strands with 4-0 nylon; group III, 3 interlaced weaves and 2 core suture strands with 4-0 FiberWire; and group IV, 4 interlaced weaves only. Each sutured tendon was placed in a Universal Testing Machine, and repair site elongation after repeated traction loads and rupture strength were measured.
The mean elongation values were 2.74 ± 0.84 mm, 1.80 ± 0.16 mm, 1.60 ± 0.18 mm, and 1.92 ± 0.18 mm for groups I, II, III, and IV, respectively. The elongation values were significantly lower in groups II, III, and IV than in group I. The mean rupture strengths were 64.9 ± 16.0 N, 94.8 ± 17.2 N, 110.9 ± 21.3 N, and 104.9 ± 17.5 N for groups I, II, III, and IV, respectively. Rupture strengths were significantly higher for groups III and IV than for group I.
After adding core sutures during Pulvertaft tendon repair, the elongation amount decreased, and the rupture strength improved.
The study showed the effect of additional core sutures during Pulvertaft tendon repair, suggesting that it could be useful in reducing postoperative tendon elongation when extensor tendon transfers are performed.
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