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Hand (New York, N.Y.) Dec 2022Distal-ulna stump (DUS) instability often occurs when performing a distal radioulnar joint (DRUJ) arthroplasty. Recent studies suggest that the distal interosseous...
BACKGROUND
Distal-ulna stump (DUS) instability often occurs when performing a distal radioulnar joint (DRUJ) arthroplasty. Recent studies suggest that the distal interosseous membrane (DIOM) reinforces the triangular fibrocartilage complex, providing additional stability to the DRUJ. The aim of this study was to determine whether the DIOM stabilizes the ulnar stump.
METHODS
Twenty fresh-frozen random forearms were dissected. The presence of a distal oblique bundle (DOB) was recorded and measured. The radius was fixed to a vise and the ulna kept free. The DRUJ was fixed with a lag screw. A bone slice was removed by transverse ulna osteotomies 10 and 15 mm proximal to the DRUJ. A 10-N force was applied to the ulna in dorsal and volar directions. Displacements were measured. The DIOM was then transected, and maneuvers and measurements were repeated and compared.
RESULTS
A distinct distal membrane was present in 70% and a cord-like DOB in 30%. The mean length was 29 mm. Its origin was proximal to the sigmoid notch; its insertion was on the distal third of the ulna, at its lateral border. This attachment is comprised between 39 and 48 mm proximal to the ulnocarpal joint. Initial displacements averaged 22 mm dorsally and 13 mm volarly. After DIOM transection, ulnar translocation increased to 31 mm dorsally and 19 mm volarly.
CONCLUSION
In DRUJ arthroplasties, the DIOM does not appear to be a stabilizer of the DUS beneath a useful threshold. Its retaining effect occurs only after an initial 22-mm dorsal displacement, which we consider not clinically admissible. Therefore, in DRUJ arthroplasties, some augmentation might be advisable.
Topics: Humans; Interosseous Membrane; Joint Instability; Biomechanical Phenomena; Cadaver; Ulna
PubMed: 34144664
DOI: 10.1177/1558944721999728 -
PloS One 2024Predating Darwin's theory of evolution, the holotype of Saurodesmus robertsoni is a long-standing enigma. Found at the beginning of 1840s, the specimen is a damaged...
Predating Darwin's theory of evolution, the holotype of Saurodesmus robertsoni is a long-standing enigma. Found at the beginning of 1840s, the specimen is a damaged stylopodial bone over decades variably assigned to turtles, archosaurs, parareptiles, or synapsids, and currently nearly forgotten. We redescribe and re-assess that curious specimen as a femur and consider Saurodesmus robertsoni as a valid taxon of a derived cynodont (?Tritylodontidae). It shares with probainognathians more derived than Prozostrodon a mainly medially oriented lesser trochanter and with the clade reuniting tritylodontids, brasilodontids, and mammaliaforms (but excluding tritheledontids) the presence of a projected femoral head, offset from the long axis of the femoral shaft; a thin, plate-like greater trochanter; a distinct dorsal eminence proximal to the medial (tibial) condyle located close to the level of the long axis of the femoral shaft and almost in the middle of the width of the distal expansion; and a pocket-like fossa proximally to the medial (tibial) condyle. Saurodesmus robertsoni is most similar to tritylodontids, sharing at least with some forms: the relative mediolateral expansion of the proximal and distal regions of the femur, the general shape and development of the greater trochanter, the presence of a faint intertrochanteric crest separating the shallow intertrochanteric and adductor fossae, and the general outline of the distal region as observed dorsally and distally. This makes Saurodesmus robertsoni the first Triassic cynodont from Scotland and, possibly, one of the earliest representatives of tritylodontids and one of the latest non-mammaliaform cynodonts worldwide. Moreover, it highlights the need for revisiting historical problematic specimens, the identification of which could have been previously hampered by the lack of adequate comparative materials in the past.
Topics: Animals; Fossils; Femur; Scotland; Biological Evolution; Phylogeny
PubMed: 38809839
DOI: 10.1371/journal.pone.0303973 -
BMC Musculoskeletal Disorders Oct 2021For optimal prosthetic anchoring in omarthritis surgery, a differentiated knowledge on the mineralisation distribution of the glenoid is important. However, database on...
BACKGROUND
For optimal prosthetic anchoring in omarthritis surgery, a differentiated knowledge on the mineralisation distribution of the glenoid is important. However, database on the mineralisation of diseased joints and potential relations with glenoid angles is limited.
METHODS
Shoulder specimens from ten female and nine male body donors with an average age of 81.5 years were investigated. Using 3D-CT-multiplanar reconstruction, glenoid inclination and retroversion angles were measured, and osteoarthritis signs graded. Computed Tomography-Osteoabsorptiometry (CT-OAM) is an established method to determine the subchondral bone plate mineralisation, which has been demonstrated to serve as marker for the long-term loading history of joints. Based on mineralisation distribution mappings of healthy shoulder specimens, physiological and different CT-OAM patterns were compared with glenoid angles.
RESULTS
Osteoarthritis grades were 0-I in 52.6% of the 3D-CT-scans, grades II-III in 34.3%, and grade IV in 13.2%, with in females twice as frequently (45%) higher grades (III, IV) than in males (22%, III). The average inclination angle was 8.4°. In glenoids with inclination ≤10°, mineralisation was predominantly centrally distributed and tended to shift more cranially when the inclination raised to > 10°. The average retroversion angle was - 5.2°. A dorsally enhanced mineralisation distribution was found in glenoids with versions from - 15.9° to + 1.7°. A predominantly centrally distributed mineralisation was accompanied by a narrower range of retroversion angles between - 10° to - 0.4°.
CONCLUSIONS
This study is one of the first to combine CT-based analyses of glenoid angles and mineralisation distribution in an elderly population. The data set is limited to 19 individuals, however, indicates that superior inclination between 0° and 10°-15°, and dorsal version ranging between - 9° to - 3° may be predominantly associated with anterior and central mineralisation patterns previously classified as physiological for the shoulder joint. The current basic research findings may serve as basic data set for future studies addressing the glenoid geometry for treatment planning in omarthritis.
Topics: Aged; Aged, 80 and over; Calcification, Physiologic; Female; Human Body; Humans; Male; Scapula; Shoulder Joint; Tomography, X-Ray Computed
PubMed: 34610804
DOI: 10.1186/s12891-021-04660-4 -
Translational Psychiatry Apr 2023Obsessive-compulsive disorder (OCD) affects 2-3% of the population. One-third of patients are poorly responsive to conventional therapies, and for a subgroup, gamma...
Obsessive-compulsive disorder (OCD) affects 2-3% of the population. One-third of patients are poorly responsive to conventional therapies, and for a subgroup, gamma knife capsulotomy (GKC) is an option. We examined lesion characteristics in patients previously treated with GKC through well-established programs in Providence, RI (Butler Hospital/Rhode Island Hospital/Alpert Medical School of Brown University) and São Paulo, Brazil (University of São Paolo). Lesions were traced on T1 images from 26 patients who had received GKC targeting the ventral half of the anterior limb of the internal capsule (ALIC), and the masks were transformed into MNI space. Voxel-wise lesion-symptom mapping was performed to assess the influence of lesion location on Y-BOCS ratings. General linear models were built to compare the relationship between lesion size/location along different axes of the ALIC and above or below-average change in Y-BOCS ratings. Sixty-nine percent of this sample were full responders (≥35% improvement in OCD). Lesion occurrence anywhere within the targeted region was associated with clinical improvement, but modeling results demonstrated that lesions occurring posteriorly (closer to the anterior commissure) and dorsally (closer to the mid-ALIC) were associated with the greatest Y-BOCS reduction. No association was found between Y-BOCS reduction and overall lesion volume. GKC remains an effective treatment for refractory OCD. Our data suggest that continuing to target the bottom half of the ALIC in the coronal plane is likely to provide the dorsal-ventral height required to achieve optimal outcomes, as it will cover the white matter pathways relevant to change. Further analysis of individual variability will be essential for improving targeting and clinical outcomes, and potentially further reducing the lesion size necessary for beneficial outcomes.
Topics: Humans; Brazil; Obsessive-Compulsive Disorder; Radiosurgery; Treatment Outcome; Internal Capsule
PubMed: 37185805
DOI: 10.1038/s41398-023-02425-2 -
Cureus May 2020A 19-year-old female presented with pain, deformity, and slightly restricted left wrist motion for five years with gradual progression. Physical examination revealed...
A 19-year-old female presented with pain, deformity, and slightly restricted left wrist motion for five years with gradual progression. Physical examination revealed volar subluxation of the left hand, dorsally prominent ulnar styloid, radial and dorsal bowing of the distal forearm, and mild restriction in wrist dorsiflexion. Radiographs showed a failure of ossification of the ulnar side of the distal radial epiphysis, increased radial inclination angle, dorsal subluxation of the distal ulna, V-shaped proximal carpal row due to proximal migration of the lunate, and increased interosseous space. A diagnosis of Madelung deformity of the left wrist was made. Conservative management with oral analgesics, activity restriction, and a volar splint was done as the patient was skeletally mature, had only mild pain with no functional limitation or gross deformity. At the six-month follow-up, she was doing well with decreased pain and no new complaints.
PubMed: 32582486
DOI: 10.7759/cureus.8225 -
Journal of Spine Surgery (Hong Kong) Sep 2017Intervertebral disc prolapse is a common cause of both acute and chronic low back pain. This can result in differential grades of motor and sensory disturbances in lower...
Intervertebral disc prolapse is a common cause of both acute and chronic low back pain. This can result in differential grades of motor and sensory disturbances in lower limbs and even cauda equina syndrome (CES). The neurological manifestations are a result of compression of the spinal cord and roots ventrally in the spinal canal due to the prolapsed disc. However, neurologic deficits owing to compression of the spinal cord dorsally as a result of migration of sequestrated disc fragments are very rare. We present two different cases of back pain with severe neurologic deficit referred to us within a short span of one month. Among them, one had long standing history of back pain while other had none. Both patients were investigated and found to have a sequestrated disc fragment which had dorsally migrated to the epidural space and was causing severe compression of the spinal cord. They underwent laminectomy and removal of the sequestrated fragment. However, they were only partially relieved of their motor and bladder weakness. We present our cases to highlight this rare form of lumbar epidural intervertebral disc migration, as well as enumerate the diagnostic challenges and discuss the differential diagnosis and treatment.
PubMed: 29057364
DOI: 10.21037/jss.2017.08.07 -
Human Brain Mapping Jul 2019Interacting with manipulable objects (tools) requires the integration of diverse computations supported by anatomically remote regions. Previous functional neuroimaging...
Interacting with manipulable objects (tools) requires the integration of diverse computations supported by anatomically remote regions. Previous functional neuroimaging research has demonstrated the left supramarginal (SMG) exhibits functional connectivity to both ventral and dorsal pathways, supporting the integration of ventrally-mediated tool properties and conceptual knowledge with dorsally-computed volumetric and structural representations of tools. This architecture affords us the opportunity to test whether interactions between the left SMG, ventral visual pathway, and dorsal visual pathway are differentially modulated when participants plan and generate tool-directed gestures emphasizing functional manipulation (tool use gesturing) or structure-based grasping (tool transport gesturing). We found that functional connectivity between the left SMG, ventral temporal cortex (bilateral fusiform gyri), and dorsal visual pathway (left superior parietal lobule/posterior intraparietal sulcus) was maximal for tool transport planning and gesturing, whereas functional connectivity between the left SMG, left ventral anterior temporal lobe, and left frontal operculum was maximal for tool use planning and gesturing. These results demonstrate that functional connectivity to the left SMG is differentially modulated by tool use and tool transport gesturing, suggesting that distinct tool features computed by the two object processing pathways are integrated in the parietal lobe in the service of tool-directed action.
Topics: Brain Mapping; Female; Gestures; Humans; Magnetic Resonance Imaging; Male; Parietal Lobe; Psychomotor Performance; Tool Use Behavior; Visual Pathways; Young Adult
PubMed: 30900321
DOI: 10.1002/hbm.24565 -
Frontiers in Veterinary Science 2020Laminitis is a debilitating disorder resulting in irreversible anatomical changes in the feet of equids. Assessing specific anatomical features through radiography and...
Laminitis is a debilitating disorder resulting in irreversible anatomical changes in the feet of equids. Assessing specific anatomical features through radiography and venography provides diagnostic and prognostic information. The reference ranges are well-established in horses, but not in donkeys. It is also uncertain as to whether these ranges can be applied to every donkey breed. The present study characterizes the radiological and venographic hoof anatomy of healthy feet of Amiata donkeys and defines the changes associated with severe and mild laminitis. A total of 16 forefeet were evaluated in 8 Amiata jennies. The animals underwent musculoskeletal examination, Obel grading assessment and radiological evaluation. Based on clinical examination and radiographic findings, the forefeet were grouped as healthy, mild or severe laminitic feet, thus the digital venograms were performed according to the group definition. Radiology revealed 7/16 healthy, 4/16 mild laminitic, and 5/16 severe laminitic forefeet. Statistical analysis showed differences between the healthy and laminitic forefeet for the dorsal angle ( < 0.0001) and angle of solar aspect ( < 0.0001) of the distal phalanx, for deviation between dorsal aspect of distal phalanx and the hoof wall ( < 0.0001) and phalangeal rotation angle ( = 0.0032). Venography was abnormal in mild and severe laminitic forefeet. In particular, the vascularization was reduced or absent at the lamellar-circumflex junction dorsally, at the sub-lamellar vascular bed and at the circumflex veins. Coronary plexus vascularization was absent in severe laminitic forefeet. This study provides the radiological parameters for the assessment of healthy and laminitic forefeet of Amiata donkeys. The mild laminitic foot venogram showed decreased vascularization mainly on lamellar-circumflex junction and sub-lamellar vascular bed, in latero-medial views. The severe laminitic foot showed very poor or absent vascularization in multiple areas. The technique is easily applicable and provides diagnostic support in laminitis.
PubMed: 33409297
DOI: 10.3389/fvets.2020.601665 -
ELife Jun 2021Primary sensory neurons are generally considered the only source of dorsal horn calcitonin gene-related peptide (CGRP), a neuropeptide critical to the transmission of...
Primary sensory neurons are generally considered the only source of dorsal horn calcitonin gene-related peptide (CGRP), a neuropeptide critical to the transmission of pain messages. Using a tamoxifen-inducible transgenic mouse, here we identified a distinct population of CGRP-expressing excitatory interneurons in lamina III of the spinal cord dorsal horn and trigeminal nucleus caudalis. These interneurons have spine-laden, dorsally directed, dendrites, and ventrally directed axons. As under resting conditions, CGRP interneurons are under tonic inhibitory control, neither innocuous nor noxious stimulation provoked significant Fos expression in these neurons. However, synchronous, electrical non-nociceptive Aβ primary afferent stimulation of dorsal roots depolarized the CGRP interneurons, consistent with their receipt of a VGLUT1 innervation. On the other hand, chemogenetic activation of the neurons produced a mechanical hypersensitivity in response to von Frey stimulation, whereas their caspase-mediated ablation led to mechanical hyposensitivity. Finally, after partial peripheral nerve injury, innocuous stimulation (brush) induced significant Fos expression in the CGRP interneurons. These findings suggest that CGRP interneurons become hyperexcitable and contribute either to ascending circuits originating in deep dorsal horn or to the reflex circuits in baseline conditions, but not in the setting of nerve injury.
Topics: Animals; Behavior, Animal; Calcitonin Gene-Related Peptide; Disease Models, Animal; Hyperalgesia; Interneurons; Mechanotransduction, Cellular; Mice, Inbred C57BL; Mice, Transgenic; Neural Inhibition; Pain Threshold; Peripheral Nerve Injuries; Physical Stimulation; Posterior Horn Cells; Proto-Oncogene Proteins c-fos; Vesicular Glutamate Transport Protein 1; Mice
PubMed: 34061020
DOI: 10.7554/eLife.59751 -
Journal of Veterinary Internal Medicine Jul 2021The Chihuahua dog breed is known for frequent occurrence of a bregmatic fontanelle on the dorsal skull. A common conception is that this skull defect is a clinically...
BACKGROUND
The Chihuahua dog breed is known for frequent occurrence of a bregmatic fontanelle on the dorsal skull. A common conception is that this skull defect is a clinically irrelevant finding. No studies, however, describe its prevalence or whether it is accompanied by other persistent fontanelles (PFs). Although Chihuahuas are predisposed to Chiari-like malformation (CM) and syringomyelia (SM), it is unknown whether PFs occur more commonly in dogs with clinical signs that are caused by CM or SM.
HYPOTHESIS/OBJECTIVES
To describe the number and location of PFs at cranial sutures (CSs) and to compare the occurrence of these PFs in dogs with and without CM/SM-related clinical signs. We hypothesized that PFs also occur commonly at lateral and caudal cranial surfaces, affect a higher number of CSs, and are larger in dogs with CM/SM-related clinical signs.
ANIMALS
Fifty client-owned Chihuahuas with or without CM/SM-related clinical signs.
RESULTS
Of the 50 dogs evaluated, 46 (92%) had either 1 or several PFs. The mean ± SD number of PFs was 2.8 ± 3.0 (range, 0-13). A total of 138 PFs occupied 118 CSs with 57 (48%) located dorsally, 44 (37%) caudally, and 17 (14%) laterally. The number of CSs affected by PFs was significantly higher (P ≤ .001) and total PF area was significantly larger (P = .003) in dogs with CM/SM-related clinical signs.
CONCLUSIONS AND CLINICAL IMPORTANCE
Persistent fontanelles are very common in this group of Chihuahuas and appear at dorsal, lateral, and caudal cranial surfaces. They are more numerous and larger in Chihuahuas with CM/SM-related clinical signs.
Topics: Animals; Arnold-Chiari Malformation; Dog Diseases; Dogs; Magnetic Resonance Imaging; Skull; Syringomyelia
PubMed: 34028887
DOI: 10.1111/jvim.16151