Spontaneous thoracic spinal cord herniation (STSCH) is an uncommon cause of thoracic myelopathy. Fewer than 40 cases have been reported in the English language literature with a mean follow-up of ...less than 6 months.
We have encountered three patients diagnosed with STSCH in the last 6 years at our institution. These patients presented with symptoms and signs localizing to the thoracic spinal cord. Magnetic resonance imaging revealed ventral thoracic spinal cord displacement in each.
One patient was treated surgically, two managed expectantly. Two patients have been followed for greater than 5 years, whereas a third has been followed for 15 months.
Our experience suggests that patients with neurological symptoms and signs attributable to STSCH may not progress and therefore may be followed with clinical and magnetic resonance imaging surveillance. When surgery is indicated for progressive STSCH, late retethering may occur.
The marginal sinus TUBBS, R. Shane; AMMAR, Kevin; LIECHTY, Peter ...
Journal of neurosurgery,
03/2006, Letnik:
104, Številka:
3
Journal Article
Recenzirano
Descriptions of the marginal venous sinus are lacking in the extant medical literature. The aim of this study was to characterize the anatomy of this intracranial venous sinus.
The authors examined ...the marginal sinuses in 15 adult cadavers following the injection of latex into the intracranial venous system. The maximal vertical height of the sinuses, which ranged from 7 to 15 mm (mean 10 mm), was located at the lateral aspect of the foramen magnum at or near the region at which the spinal accessory nerve crossed en route to the jugular foramen. In all specimens the sinus tapered as it traveled both anteriorly and posteriorly. Ninety-three percent of the specimens demonstrated significant drainage into the veins of the hypoglossal canal. The hypoglossal nerve rootlets pierced the sinus and its tributaries in 11 (73%) of 15 specimens. The marginal sinus communicated with the basilar venous plexus in 12 (80%) of 15 specimens and with the occipital sinus in all specimens (100%). There was venous communication with the sigmoid sinus in all specimens. The vertebral artery coursed through the marginal sinus as it pierced the posterior atlantooccipital membrane in all left sides and in 87% of the right sides.
These quantitative data will be useful to the neurosurgeon who operates in the region of the marginal sinus.
INTRODUCTION:
In complex spine surgery, current pedicle screw systems with 5.5 mm titanium, cobalt chromium or stainless steel rods have rod failure rates of approximately 9% with a minimum of 1-year ...follow-up. The fracture rate with these alloys increases to approximately 22% in PSO cases.
1
Molybdenum-rhenium has demonstrated superior yield strength and fatigue endurance limit compared to Ti-6Al-4V and CoCr.
METHODS:
Retrospective, multicenter, case series. Inclusion criteria were = 4 levels posterior instrumented fusion with 4.5 mm molybdenum-rhenium rods, age = 18 yrs and 6 months or longer radiographic and followup.
RESULTS:
One hundred and fifty-nine (159) consecutive patients from ten different medical centers that had spinal surgery from August 2019 until April 2022 met inclusion criteria. Mean age was 63 ± 11.8 years; 50% women; 31% smokers; 19% diabetic and the mean BMI was 30 ± 7.3. The mean number of levels fused was 5.9 ± 2.7; 22.6% 4 levels, 64.2% 5-9 levels and 13.2% 10 levels or greater. Approximately half were thoracolumbar (27.7%) or thoracolumbar to pelvis (24.5%) and approximately half were lumbar-sacral (47.2%). Thirty-eight patients (24%) had a PSO and 59 patients (39%) had a SPO. All cases were done with molybdenum-rhenium 4.5 mm diameter rods. There were no RFs reported in the 159 cases (0/159; 0.0%) at 22.36 months mean follow-up.
CONCLUSIONS:
There was no incidence of RF in the 159 consecutive patients who underwent complex spine surgery involving multiple levels and osteotomies. A pedicle screw system based upon molybdenum-rhenium 4.5 mm rods provides superior fracture resistance particularly in complex spine procedures.
1 Smith JS, et al., Prospective multicenter assessment of risk factors for rod fracture following surgery for adult spinal deformity. J Neurosurg Spine. 2014 Dec; 21(6): 994-1003.
Metals from spinal implants are released into surrounding tissues by various mechanisms. Metal ion release has been associated with clinical implant failure, osteolysis, and remote site accumulation ...with adverse events. Significant corrosion and associated metal ion release has been described with currently used spinal implant alloys. A novel metal alloy, Molybdenum-47.5Rhenium alloy (MoRe®), was approved for use in medical implants in 2019 by the FDA.
To evaluate the metal ion release profile of MoRe alloy after immersion in both a stable physiologic, as well as in an inflammatory environment.
In vitro study.
The ion release profile of the MoRe alloy was comprehensively evaluated in-vitro after prolonged immersion in physiologic and inflammatory environments. Ion concentration analyses were then conducted using inductively coupled plasma-mass spectrometry (ICP-MS) methods. Comparative testing of titanium (Ti-6Al-4V) and cobalt chromium (Co-28Cr-6Mo) was also performed.
Under baseline physiologic conditions, the MoRe alloy demonstrates very low molybdenum and rhenium ion release rates throughout the 30-day test period. During the first time interval (day 0–1), low levels of molybdenum and rhenium ions are detected (<0.3 μg/cm2 day) followed by a rapid reduction in the ion release rates to <0.05 μg/cm2 day during the second time interval (days 1–3) followed by a further reduction to very low steady-state rates <0.01 μg/cm2 day during the third time interval (days 3–7), which were maintained through 30 days. In the inflammatory condition (H2O2 solution), there was a transient increase in the release of molybdenum and rhenium ions, followed by a return to baseline ion release rates (days 2–4), with a further reduction to low steady-state rates of ∼0.01 μg/cm2 day (days 4–8). The measured molybdenum and rhenium ion release rates in both steady state (<0.01 μg/cm2 day), and inflammatory environments (0.01 μg/cm2 day) were far below the established FDA-permitted daily exposure (PDE) of 1,900 μg/cm2 day for molybdenum and 4,400 μg/cm2 day for rhenium. In contrast, titanium and cobalt chromium approached or exceeded their established PDE values in an inflammatory environment.
The novel biomaterial MoRe demonstrated a lower metal ion release profile in both a physiologic and inflammatory environment and was well below the established PDE. Comparative testing of the cobalt-chromium and titanium alloys found higher levels of ion release in the inflammatory environment that exceeded the PDE for cobalt and vanadium.
Avoidance of injury to the thoracic duct during neurosurgical procedures involving the cervical region depends on a working knowledge of its location. This study evaluates superficial anatomic ...landmarks for the cervical portion of the thoracic duct that may be encountered in neurosurgery of the neck.
Fifteen dissections of human cadavers were performed to study the relationship between the proximal thoracic duct and superficial landmarks (e.g., the cricoid cartilage and sternal notch of the manubrium).
The cervical portion of the thoracic duct was found to be approximated by a roughly 4.4-cm(2) region in the left supraclavicular area beginning approximately 2.0 cm lateral to the midline and 3.5 cm superior to the sternal notch, extending superiorly to a point roughly 3.5 cm from the midline and 2.5 cm inferior to the cricoid cartilage, and terminating within the venous system at a point approximately 4.5 cm lateral to the midline and 3.0 cm superior to the sternal notch.
Through an increased appreciation for its location, injury to the thoracic duct may be minimized.
Differentiation between neoplastic and nonneoplastic conditions magnetic resonance imaging(MRI) has established itself as one of the key clinical tools in evaluation of musculoskeletal pathology. ...However, MRI still has several key limitations which require supplemental information from additional modalities to complete evaluation of various disorders. This has led to the development hybrid positron emission tomography(PET)-MRI which is rapidly evolving to address key clinical questions by using the morphological strengths of MRI and functional information of PET imaging. In this article, we aim to review physical principles and techniques of PET-MRI and discuss clinical utility of functional information obtained from PET imaging and structural information obtained from MRI imaging for the evaluation of musculoskeletal pathology. More specifically, this review highlights the role of PET-MRI in musculoskeletal oncology including initial diagnosis and staging, treatment planning and posttreatment follow-up. Also we will review utility of PET-MRI in evaluating musculoskeletal infections(especially in the immunocompromised and diabetics) and inflammatory condition. Additionally, common pitfalls of PET-MRI will be addressed.
A proposal for new diagnostic criteria for ALS Shefner, Jeremy M.; Al-Chalabi, Ammar; Baker, Mark R. ...
Clinical neurophysiology,
August 2020, 2020-08-00, 20200801, Letnik:
131, Številka:
8
Journal Article
The purpose of this article is to review the imaging features of necrotizing fasciitis and its potential mimics. Key imaging features are emphasized to enable accurate and efficient interpretation of ...variables that are essential in appropriate management.
Necrotizing fasciitis is a medical emergency with potential lethal outcome. Dissecting gas along fascial planes in the absence of penetrating trauma (including iatrogenic) is essentially pathognomonic. However, the lack of soft-tissue emphysema does not exclude the diagnosis. Mimics of necrotizing fasciitis include nonnecrotizing fasciitis (eosinophilic, paraneoplastic, inflammatory (lupus myofasciitis, Churg-Strauss, nodular, or proliferative), myositis, neoplasm, myonecrosis, inflammatory myopathy, and compartment syndrome. Necrotizing fasciitis is a clinical diagnosis, and imaging can reveal nonspecific or negative findings (particularly during the early course of disease). One should be familiar with salient clinical and imaging findings of necrotizing fasciitis to facilitate a more rapid and accurate diagnosis and be aware that its diagnosis necessitates immediate discussion with the referring physician.
Miller-Dieker syndrome (MDS) is caused by a heterozygous deletion of chromosome 17p13.3 involving the genes LIS1 and YWHAE (coding for 14.3.3ε) and leads to malformations during cortical development. ...Here, we used patient-specific forebrain-type organoids to investigate pathological changes associated with MDS. Patient-derived organoids are significantly reduced in size, a change accompanied by a switch from symmetric to asymmetric cell division of ventricular zone radial glia cells (vRGCs). Alterations in microtubule network organization in vRGCs and a disruption of cortical niche architecture, including altered expression of cell adhesion molecules, are also observed. These phenotypic changes lead to a non-cell-autonomous disturbance of the N-cadherin/β-catenin signaling axis. Reinstalling active β-catenin signaling rescues division modes and ameliorates growth defects. Our data define the role of LIS1 and 14.3.3ε in maintaining the cortical niche and highlight the utility of organoid-based systems for modeling complex cell-cell interactions in vitro.
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•Homogeneous forebrain-type organoids reflect early cortical development in vitro•MDS-derived organoids show reduced expansion rate caused by premature neurogenesis•MDS-derived organoids exhibit alterations in cortical niche architecture•Niche disruption leads to a non-cell-autonomous disturbance of β-catenin signaling
Using Miller-Dieker-syndrome-specific iPSC-derived forebrain-type organoid cultures, Iefremova et al. find that a disturbance of cortical niche signaling leads to alterations in N-cadherin/β-catenin signaling that result in a non-cell-autonomous expansion defect of ventricular zone radial glia cells.
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