Is It Possible to Perform Fifth Carpometacarpal Joint Arthroscopy? Cadaveric Study on Its Feasibility, Safety, and Potential Hazards in Portal Creation

Background Fifth carpometacarpal joint (CMCJ) fracture dislocation is a relatively rare injury and most will require operative treatment because of its unstable nature. Improper reduction and fixation lead to joint surface destruction, pain, and reduced grasping power. Intra-articular fragment reduction is often obscured by dorsally displaced ulnar fragment. Therefore, fifth CMCJ arthroscopy can be advantageous in assisting intra-articular fragment reduction. However, there is no detailed description of the portal landmarks or portals' relationship with adjacent important structures in the literature. Purposes To explore the feasibility and safety of fifth CMCJ arthroscopy, locations of the portals are examined in cadaveric hand specimens. Their proximity to important anatomical structures such as dorsal cutaneous branch of ulnar nerve (DCBUN), ring finger and little finger extensor digitorum communis (EDC), and extensor digiti minimi (EDM) is measured. Methods Fifth CMCJ arthroscopy is performed on 11 cadaveric hand specimens by specialist-level surgeon. The portals are marked and portal positions are further confirmed under the fluoroscopy. Then the cadaveric specimens were undergone anatomical dissection by specialist-level surgeon. During dissection, the spatial relationship between the portal positions and DCBUN, EDC to ring finger and little finger, and EDM is identified. The distance between the portals and the above important structures was measured in millimeters. Results DCBUN was consistently found between fourth metacarpohamate (4-MH) and fifth metacarpohamate (5-MH) portals, with it being closer to the latter (mean distance, 2.03 mm; range, 0–4.43 mm; standard deviation [SD], 1.09 mm). The closest tendon for 4-MH portal is ring finger EDC (mean distance, 2.65 mm; range, 0–5.89 mm; SD, 1.78 mm), while 5-MH portal and accessory portal were closest to EDC (mean distance, 1.88 mm; range, 0–3.69 mm; SD, 1.25 mm) and EDM (mean distance, 7.79 mm; range, 6.63–10.72 mm; SD, 1.49 mm), respectively. During the process of specimen dissection, we found no damage to the above structures after portal introduction. Conclusion The above findings support the use of fifth CMCJ arthroscopy, which can be used for assisted reduction in fifth metacarpal base fracture dislocation and hamate body fracture. Gentle soft tissue spreading technique during portal creation prevents injury to the important structure surrounding the portals. Level of evidence This is a Level V study.

Anatomical step-by-step dissection of complex skull base approaches for trainees: Endoscopic endonasal approach to the orbit

Introduction: Although endonasal endoscopic approaches (EEA) to the orbit have been previously reported, a didactic resource for educating neurosurgery and otolaryngology trainees regarding the pertinent anatomy, techniques, and decision-making pearls is lacking. Methods: Six sides of three formalin-fixed, color latex-injected cadaveric specimens were dissected using 4-mm 0º and 30º rigid endoscopes, as well as standard endoscopic equipment, and a high-speed surgical drill. The anatomical dissection was documented in stepwise 3-D endoscopic images. Following dissection, representative case applications were reviewed. Results: EEA to the orbit provides excellent access to the medial and inferior orbital regions. Key steps include positioning and preoperative considerations, middle turbinate medialization, uncinate process and ethmoid bulla removal, complete ethmoidectomy, sphenoidotomy, maxillary antrostomy, lamina papyracea resection, orbital apex and optic canal decompression, orbital floor resection, periorbita opening, dissection of the extraconal fat, and final exposure of the orbit contents via the medial-inferior recti corridor. Conclusion: EEA to the orbit is challenging, in particular for trainees unfamiliar with nasal and paranasal sinus anatomy. Operatively oriented neuroanatomy dissections are crucial didactic resources in preparation for practical endonasal applications in the OR. This approach provides optimal exposure to the inferior and medial orbit to treat a wide variety of pathologies. We describe a comprehensive step-by-step curriculum directed to any audience willing to master this endoscopic skull base approach.

Sacral insufficiency fractures are a risk of massive bleeding during sacrectomy: patient series

BACKGROUND Sacrectomy carries significant risk of bleeding; however, specific risk factors, apart from medical comorbidities and tumor type, for this life-threatening complication remain unclear. This study describes two cases of massive bleeding, including one death during sacrectomy attributable to adherence of the internal iliac vein (IIV) and its neuroforaminal tributaries from sacral insufficiency fractures. OBSERVATIONS The authors presented two cases involving patients who received sacrectomy for a chordoma and experienced massive bleeding from the IIV due to adherence of the IIV and its neuroforaminal tributaries around sacral insufficiency fractures. They assessed their institution’s previous two decades’ experience of sacrectomies to determine risk factors for massive bleeding and performed anatomical dissection of 20 hemipelvises, which revealed the close proximity of the IIV to the sacral foraminae and the consistency of neuroforaminal tributaries arising from the foraminae. LESSONS Sacral insufficiency fractures may cause scarring that adheres to the IIV and its neuroforaminal tributaries, which risks massive bleeding during sacrectomy.

Computational Imaging-Processing Comparison for Lumbar Spine Cadaveric Specimens with Clinical Medical Physics Applications

A series of improved imaging-computational and algorithmic methods for new/different lumbar cadaveric specimens was obtained. These are based on previous publications [3,3.1], with an improved-imaging research line. Results show a systematic study of each lumbar cadaveric specimen. Enhanced imaging findings and resolution for vertebral facets/positioning, contrast, anatomical parts separation and visualization of lumbar spines are demonstrated. Medical Physics and clinical bioengineering advances related to previous contributions are proven with imaging processing, programming codes/patterns, and computer vision tools. Findings constitute computational imaging methods which are appropriate for sharp and detailed anatomical-clinical analysis and comparisons among cadaveric specimens. These processing solutions are useful for lumbar spine computational study and anatomical dissection. Applications on Medical Physics, Biomedical Engineering, and Computational-Forensic Diagnosis are obtained from this cadaveric imaging systematic comparison and software methods.

Arthroscopic Lunotriquetral Ligamentoplasty, from the Cadaver Lab to the Clinical Practice

Introduction There has been an increase in the diagnosis of injuries to the intrinsic ligaments of the wrist due to the more widespread use of arthroscopy in the treatment of patients with musculoskeletal wrist pain, and arthroscopy is particularly very helpful to determine the etiology of these lesions at the ulnar level. The treatment of lunotriquetral ligament injuries encompasses different techniques with results that are little reproducible. Ligament reconstruction through tendon grafting has shown favorable results, but it involves extensive open approaches that lead to a slower recovery a lower range of joint motion due to the excess of scar tissue. The objective of the present study is to describe the performance, in a cadaver, of a minimally-invasive lunotriquetral and secondary-stabilizer ligamentoplasty and its application in a representative clinical case. Material and Methods A preliminary study of six specimens in which a lunotriquetral and secondary-stabilizer ligamentoplasty was performed consecutively through a free tendon graft with arthroscopic assistance. We proceeded to recreate the complete ligament injury, and to perform an assessment of lunotriquetral instability according to the Geissler classification and an arthroscopic ballottement test. We describe the surgical technique, ligament stability after the ligamentoplasty, and the subsequent anatomical dissection, assessing the anatomical structures susceptible to iatrogenic injury. We also describe the application of the technique in one case, comparing the clinical parameters before and after the procedure: range of motion of the joint, strength, pain and the shortened version of the Disabilities of the Arm, Hand, and Shoulder (QuickDASH) questionnaire. Results The ligamentoplasties performed showed recovery of the stability of the lunotriquetral interval assessed according to the Geissler classification and the arthroscopic ballottement test. In the dissection of the specimens, no iatrogenic lesions were found in the tendons or the surfaces of the mediocarpal and radiocarpal joints. The average distances between the nearest bone tunnels and nerves were of 7.3 mm for the sensory branch of the ulnar nerve, of 3.6 mm for the posterior interosseous nerve, and of 4.5 mm for the ulnar neurovascular bundle. No fractures were observed in the tunnelled bones. In the clinical case herein presented, six months after the intervention, there was an improvement in strength and preoperative pain, with a slight decrease in the joint range of motion (15% compared to the contralateral joint). Conclusions The lunotriquetral ligamentoplasty herein described could contribute to the biomechanical restoration of the carpus and be an option for recosntruction in selected cases. Its performance through minimally-invasive techniques, and the use of a free tendon graft together with specific rehabilitation should be considered to optimize the outcomes.

A New Inspiration in Bionic Shock Absorption Midsole Design and Engineering

Inspired by the performance of the ostrich in terms of loading and high-speed moving ability, the purpose of this study was to design a structure and material on the forefoot and heel of the middle soles of sports shoes based on the high cushioning quality of the ostrich toe pad by applying bionic engineering technology. The anatomical dissection method was used to analyze the ostrich foot characteristics. The structure and material of the bionic shock absorption midsole were designed according to the principles of bionic engineering and reverse engineering. F-Scan and numerical simulation were used to evaluate the bionic shock absorption midsole performance. The results showed that the bionic shock absorption midsole decreased the peak pressure (6.04–12.27%), peak force (8.62–16.03%), pressure–time integral (3.06–12.66%), and force–time integral (4.06–10.58%) during walking and brisk walking. In this study, the biomechanical effects to which the bionic shock absorption midsole structure was subjected during walking and brisk walking exercises were analyzed. The bionic midsole has excellent shock resistance. It is beneficial for the comfort of the foot during exercise and might reduce the risk of foot injuries during exercise.

A groupwise registration and tractography framework for cardiac myofiber architecture description by diffusion MRI: an application to the ventricular junctions

BackgroundKnowledge of the normal myocardial–myocyte orientation could theoretically allow the definition of relevant quantitative biomarkers in clinical routine to diagnose heart pathologies. A whole heart diffusion tensor template representative of the global myofiber organization over species is therefore crucial for comparisons across populations. In this study, we developed a template-based and tractography framework to resolve the global myofiber arrangement of large mammalian hearts. To demonstrate the potential application of the proposed method, a novel description of sub-regions in the intraventricular septum is presented.MethodsThree explanted sheep (ovine) hearts (size ~12×8×6 cm3, heart weight ~ 150 g) were perfused with contrast agent and fixative and imaged in a 9.4T magnet. A group-wise registration of high-resolution anatomical and diffusion-weighted images were performed to generated anatomical and diffusion tensor templates. Diffusion tensor metrics (eigenvalues, eigenvectors, fractional anisotropy …) were computed to provide a quantitative and spatially-resolved analysis of cardiac microstructure. Then tractography was performed using deterministic and probabilistic algorithms and used for different purposes: i) Visualization of myofiber architecture, ii) Segmentation of sub-area depicting the same fiber organization, iii) Seeding and Tract Editing. Finally, dissection was performed to confirm the existence of macroscopic structures identified in the diffusion tensor template.ResultsThe template creation takes advantage of high-resolution anatomical and diffusion-weighted images obtained at an isotropic resolution of 150 μm and 600 μm respectively, covering ventricles and atria and providing information on the normal myocardial architecture. The diffusion metric distributions from the template were found close to the one of the individual samples validating the registration procedure. Small new sub-regions exhibiting spatially sharp variations in fiber orientation close to the junctions of the septum and ventricles were identified. Each substructure was defined and represented using streamlines. The existence of a bundle of fibers in the posterior junction was validated by anatomical dissection. A complex structural organization of the anterior junction in comparison to the posterior junction was evidenced by the high-resolution acquisition.ConclusionsA new framework combining cardiac template generation and tractography was applied on the whole sheep heart. The framework can be used for anatomical investigation, characterization of microstructure and visualization of myofiber orientation across samples. Finally, a novel description of the ventricular junction in large mammalian hearts was proposed.