Peri-prosthetic Fat Grafting Decreases Collagen Content, Density, and Fiber Alignment of Implant Capsules

ABSTRACT Biochemical and histological changes in the aortic wall of rabbits were demonstrated following injection of epinephrine and l-thyroxine during 2 weeks. The widespread gross and microscopic changes were accompanied by an increase in hexosamine content and uptake of 35S labeled sodium sulphate, and an increased calcium content, whereas the collagen content, assessed by determination of hydroxyproline, was reduced. Comparison with the effect of epinephrine injections alone showed that thyroxine intensified the damaging effect of epinephrine on the vessel wall and induced more pronounced mucopolysaccharide changes in the aortic wall, presumably acting as a link in the healing processes.

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Magnetic Fields Enable Precise Spatial Control of Electrospun Fiber Alignment for Fabricating Complex Gradient Materials

10.26434/chemrxiv.13040804.v1 ◽

2020 ◽

Author(s):

R. Kevin Tindell ◽

Lincoln Busselle ◽

Julianne Holloway

Keyword(s):

Magnetic Field ◽

Electrospun Fiber ◽

Cell Phenotype ◽

Fibrous Materials ◽

Fibrous Scaffold ◽

Spatial Control ◽

Fiber Alignment ◽

Aligned Fibers ◽

The Magnetic Field ◽

Magnetically Assisted

<div>Musculoskeletal interfacial tissues consist of complex gradients in structure, cell phenotype, and biochemical signaling that are important for function. Designing tissue engineering strategies to mimic these types of gradients is an ongoing challenge. In particular, new fabrication techniques that enable precise spatial control over fiber alignment are needed to better mimic the structural gradients present in interfacial tissues, such as the tendon-bone interface. Here, we report a modular approach to spatially controlling fiber alignment using magnetically-assisted electrospinning. Electrospun fibers were highly aligned in the presence of a magnetic field and smoothly transitioned to randomly aligned fibers away from the magnetic field. Importantly, magnetically-assisted electrospinning allows for spatial control over fiber alignment at sub-millimeter resolution along the length of the fibrous scaffold similar to the native structural gradient present in many interfacial tissues. The versatility of this approach was further demonstrated using multiple electrospinning polymers and different magnet configurations to fabricate complex fiber alignment gradients. As expected, cells seeded onto gradient fibrous scaffolds were elongated and aligned on the aligned fibers and did not show a preferential alignment on the randomly aligned fibers. Overall, this fabrication approach represents an important step forward in creating gradient fibrous materials and are promising as tissue-engineered scaffolds for regenerating functional musculoskeletal interfacial tissues. <br></div>

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Magnetic Fields Enable Precise Spatial Control of Electrospun Fiber Alignment for Fabricating Complex Gradient Materials

10.26434/chemrxiv.13040804 ◽

2020 ◽

Author(s):

R. Kevin Tindell ◽

Lincoln Busselle ◽

Julianne Holloway

Keyword(s):

Magnetic Field ◽

Electrospun Fiber ◽

Cell Phenotype ◽

Fibrous Materials ◽

Fibrous Scaffold ◽

Spatial Control ◽

Fiber Alignment ◽

Aligned Fibers ◽

The Magnetic Field ◽

Magnetically Assisted

<div>Musculoskeletal interfacial tissues consist of complex gradients in structure, cell phenotype, and biochemical signaling that are important for function. Designing tissue engineering strategies to mimic these types of gradients is an ongoing challenge. In particular, new fabrication techniques that enable precise spatial control over fiber alignment are needed to better mimic the structural gradients present in interfacial tissues, such as the tendon-bone interface. Here, we report a modular approach to spatially controlling fiber alignment using magnetically-assisted electrospinning. Electrospun fibers were highly aligned in the presence of a magnetic field and smoothly transitioned to randomly aligned fibers away from the magnetic field. Importantly, magnetically-assisted electrospinning allows for spatial control over fiber alignment at sub-millimeter resolution along the length of the fibrous scaffold similar to the native structural gradient present in many interfacial tissues. The versatility of this approach was further demonstrated using multiple electrospinning polymers and different magnet configurations to fabricate complex fiber alignment gradients. As expected, cells seeded onto gradient fibrous scaffolds were elongated and aligned on the aligned fibers and did not show a preferential alignment on the randomly aligned fibers. Overall, this fabrication approach represents an important step forward in creating gradient fibrous materials and are promising as tissue-engineered scaffolds for regenerating functional musculoskeletal interfacial tissues. <br></div>

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Microsurgical anatomy and treatment of dural defects in spontaneous spinal cerebrospinal fluid leaks

Journal of Neurosurgery Spine ◽

10.3171/2020.6.spine20487 ◽

2020 ◽

pp. 1-9

Author(s):

Ako Matsuhashi ◽

Keisuke Takai ◽

Makoto Taniguchi

Keyword(s):

Dura Mater ◽

Fat Grafting ◽

Thoracolumbar Junction ◽

Microsurgical Anatomy ◽

Dural Defect ◽

Ct Myelography ◽

Blood Patch ◽

Neurosurgical Treatment ◽

Dural Defects ◽

Csf Leaks

OBJECTIVESpontaneous spinal CSF leaks are caused by abnormalities of the spinal dura mater. Although most cases are treated conservatively or with an epidural blood patch, some intractable cases require neurosurgical treatment. However, previous reports are limited to a small number of cases. Preoperative detection and localization of spinal dural defects are difficult, and surgical repair of these defects is technically challenging. The authors present the anatomical characteristics of dural defects and surgical techniques in treating spontaneous CSF leaks.METHODSAmong the consecutive patients who were diagnosed with spontaneous CSF leaks at the authors’ institution between 2010 and 2020, those who required neurosurgical treatment were included in the study. All patients’ clinical information, radiological studies, surgical notes, and outcomes were reviewed retrospectively. Outcomes of two different procedures in repairing dural defects were compared.RESULTSAmong 77 patients diagnosed with spontaneous CSF leaks, 21 patients (15 men; mean age 57 years) underwent neurosurgery. Dural defects were detected by FIESTA MRI in 7 patients, by CT myelography in 12, by digital subtraction myelography in 1, and by dynamic CT myelography in 1. The spinal levels of the defects were localized at the cervicothoracic junction in 16 patients (76%) and thoracolumbar junction in 4 (19%). Intraoperative findings revealed that the dural defects were small, circumscribed longitudinal slits located at the ventral aspect of the dura mater. The median dural defect size was 5 × 2 mm. The presence of dural defects at the thoracolumbar junction was associated with manifestation of an altered mental status, which was an unusual manifestation of CSF leaks (p = 0.003). Eight patients were treated via the posterior transdural approach with watertight primary sutures of the ventral defects, and 13 were treated with muscle or fat grafting. Regardless of the two different procedures, postoperative MRI showed either complete disappearance or significant reduction of the extradural CSF collection. No patient experienced postoperative neurological deficits. Clinical symptoms improved or stabilized in 20 patients with a median follow-up of 12 months.CONCLUSIONSDural defects in spontaneous CSF leaks were small, circumscribed longitudinal slits located ventral to the spinal cord at either the cervicothoracic or thoracolumbar junction. Muscle/fat grafting may be an alternative treatment to watertight primary sutures of ventral dural defects with a good outcome.

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