Abstract Biomechanics, the application of mechanical principles to living organisms, helps us to understand how all the bony and soft spinal components contribute individually and together to ensure ...spinal stability, and how traumas, tumours and degenerative disorders exert destabilizing effects. Spine stability is the basic requirement to protect nervous structures and prevent the early mechanical deterioration of spinal components. The literature reports a number of biomechanical and clinical definitions of spinal stability, but a consensus definition is lacking. Any vertebra in each spinal motion segment, the smallest functional unit of the spine, can perform various combinations of the main and coupled movements during which a number of bony and soft restraints maintain spine stability. Bones, disks and ligaments contribute by playing a structural role and by acting as transducers through their mechanoreceptors. Mechanoreceptors send proprioceptive impulses to the central nervous system which coordinates muscle tone, movement and reflexes. Damage to any spinal structure gives rise to some degree of instability. Instability is classically considered as a global increase in the movements associated with the occurrence of back and/or nerve root pain. The assessment of spinal instability remains a major challenge for diagnostic imaging experts. Knowledge of biomechanics is essential in view of the increasing involvement of radiologists and neuroradiologists in spinal interventional procedures and the ongoing development of new techniques and devices. Bioengineers and surgeons are currently focusing on mobile stabilization systems. These systems represent a new frontier in the treatment of painful degenerative spine and aim to neutralize noxious forces, restore the normal function of spinal segments and protect the adjacent segments. This review discusses the current concepts of spine stability.
Abstract
Flow diverter devices have gained wide acceptance for the treatment of unruptured intracranial aneurysms. Most studies are based on the treatment of large aneurysms harboring on the carotid ...syphon. However, during the last years the “off-label” use of these stents has widely grown up even if not supported by randomized studies. This review examines the relevant literature concerning “off-label” indications for flow diverter devices, such as for distal aneurysms, bifurcation aneurysms, small aneurysms, recurrent aneurysms, and direct carotid cavernous fistulas.
Comfortable and easy to wear systems are gaining popularity for monitoring physiological parameters. Among others, smart textiles based on fiber optic sensors have shown promising results for ...respiratory monitoring and applications in magnetic resonance (MR) environment. The aim of this paper was to design, fabricate, and assess on healthy volunteers a smart textile based on fiber Bragg grating (FBG) sensors for respiratory monitoring. The new design was driven by the chest wall kinematics analysis performed by a marked-based motion capture system. The proposed textile shows promising performances for the non-intrusive monitoring of both compartmental and global volumetric parameters over time. Moreover, the use of FBGs makes the system MR-compatible. This feature was tested on two volunteers. The system did neither cause any image artifacts nor discomfort to the volunteers. This promising result encourages future developments to investigate the feasibility of the proposed smart textile for long-term observation of respiratory parameters, for patients monitoring during MR scan, and during sport activities in athletes.
A direct aspiration, first pass technique (ADAPT) has been introduced as a rapid and safe thrombectomy strategy in patients with intracranial large vessel occlusion (LVO). The aim of the study is to ...determine the technical feasibility, safety, and functional outcome of ADAPT using the newly released large bore pHLO 0.072-inch aspiration catheter (AC; Phenox).
We performed a retrospective analysis of data collected prospectively (October 2019-November 2021) from 2 comprehensive stroke centers. Accessibility of the thrombus, vascular recanalization, time to recanalization, and procedure-related complications were evaluated. National Institutes of Health stroke scale scores at presentation and discharge and the modified Rankin scale (mRS) score at 90 days post-procedure were recorded.
Twenty-five patients (14 female, 11 male) with occlusions of the anterior circulation were treated. In 84% of cases, ADAPT led to successful recanalization with a median procedure time of 28 minutes. In the remaining cases, successful recanalization required (to a total of 96%; modified thrombolysis in cerebral infarction score 2b/3) the use of stent retrievers. No AC-related complications were reported. Other complications included distal migration of the thrombus, requiring a stent-retriever, and symptomatic PH2 hemorrhage in 16% and 4%, respectively. After 3 months, 52% of the patients had mRS scores of 0-2 with an overall mortality rate of 20%.
Results from our retrospective case series revealed that thrombectomy of LVOs with pHLO AC is safe and effective in cases of large-vessel ischemic stroke. Rates of complete or near-complete recanalization after the first pass with this method might be used as a new benchmark in future trials.
To elucidate the mechanism of action of intradiscal oxygen-ozone therapy for herniated intervertebral disc therapy.
Ozone's mechanism of action was investigated using 3 approaches: mathematical ...models of intervertebral disc space to explore the relationship between disc pressure and volume; ozonolysis experiments using glycosaminoglycans (GAGs) from a Chinese hamster ovary cell line that were similar in composition to GAGs found in human nucleus pulposus; and experiments in which live Yucatan miniature pigs received various concentrations of percutaneous, image-guided intradiscal oxygen-ozone treatment and were examined (after sacrifice) with histology and semiquantitative analysis of disc cytokine concentrations.
Engineering calculations support observations that a small (6%) disc volume reduction can result in considerable (9.84%) intradiscal pressure reduction. Porcine disc histology and Chinese hamster ovary GAG ozonolysis results showed that administered ozone reacted with and fragmented disc proteoglycans, reducing disc volume through disc dehydration. Cytokine analysis of porcine discs found that each of 4 cytokines measured (interleukin IL-1β, IL-6, IL-8, and tumor necrosis factor α) increased in concentration after 2 wt% ozone treatment.
Oxygen-ozone therapy breaks down proteoglycan GAGs that maintain disc osmotic pressure, dehydrating the nucleus pulposus and reducing intervertebral disc volume. This is likely a primary mechanism by which ozone relieves nerve root compression and alleviates herniated disc-related pain. Additionally, 2 wt% ozone appears to interact with intradiscal cytokines, generating an antiinflammatory response that may contribute to symptom improvement.
To determine statistically significant effects of oxygen/ozone treatment of herniated discs with respect to pain, function, and complication rate.
Random-effects metaanalyses were used to estimate ...outcomes for oxygen/ozone treatment of herniated discs. A literature search provided relevant studies that were weighted by a study quality score. Separate metaanalyses were performed for visual analog scale (VAS), Oswestry Disability Index (ODI), and modified MacNab outcome scales, as well as for complication rate. Institutional review board approval was not required for this retrospective analysis.
Twelve studies were included in the metaanalyses. The inclusion/exclusion criteria, patient demographics, clinical trial rankings, treatment procedures, outcome measures, and complications are summarized. Metaanalyses were performed on the oxygen/ozone treatment results for almost 8,000 patients from multiple centers. The mean improvement was 3.9 for VAS and 25.7 for ODI. The likelihood of showing improvement on the modified MacNab scale was 79.7%. The means for the VAS and ODI outcomes are well above the minimum clinically important difference and the minimum (significant) detectable change. The likelihood of complications was 0.064%.
Oxygen/ozone treatment of herniated discs is an effective and extremely safe procedure. The estimated improvement in pain and function is impressive in view of the broad inclusion criteria, which included patients ranging in age from 13 to 94 years with all types of disc herniations. Pain and function outcomes are similar to the outcomes for lumbar discs treated with surgical discectomy, but the complication rate is much lower (<0.1%) and the recovery time is significantly shorter.
Endovascular thrombectomy is the standard treatment in selected patients with acute ischemic stroke and large vessel occlusion, but continuous improvement in angiographic and clinical outcome is ...still needed. Intra-arterial thrombolysis has been tested as a possible rescue tool in unsuccessful thrombectomy, or as an adjuvant therapy after the endovascular procedure, to pursue complete recanalization. Here we present a case series analysis of intra-arterial alteplase administration (5 mg bolus, repeated up to 15 mg if Thrombolysis in Cerebral Infarction (TICI) scale ≥2c is not achieved) in 15 consecutive anterior circulation stroke patients after unsuccessful thrombectomy, defined as TICI score ≤2b after at least 3 passes or if unsuitable for further endovascular attempts, with the aim of improving recanalization. An improvement of final TICI score was achieved in 10 of 15 patients (66.7%). TICI score ≥2c was achieved after 5 mg intra-arterial tissue plasminogen activator (iaTPA) in 4 patients, and after 10 mg iaTPA in 5 cases. Six of 15 patients received 15 mg iaTPA: 1 of 6 showed angiographical improvement. A major effect of intra-arterial alteplase was observed for distally migrated emboli. None of the patients experienced any symptomatic hemorrhagic transformation or other major bleeding. Our report shows, in a very small cohort, a high rate of final TICI score improvement, encouraging the development of randomized controlled trials of rescue intra-arterial thrombolysis in patients with suboptimal angiographic results after mechanical thrombectomy.
Introduction
This study aimed to determine changes in size of lumbar spinal canal and related articular structures, during dynamic MR scans acquired in symptomatic patients standing upright using a ...new open MR system.
Methods
Forty patients (mean age 58.4 years) affected by lumbar back pain associated with claudication, referring symptoms since more than 6 months. No one underwent to previous spine surgery. MR scans were performed with a novel open 0.5-T scanner, patient supine and upright (90°). Lumbar lordotic angle, flavum ligament thickness, herniated discs, spinal canal area, spinal canal and dural sac antero-posterior diameters, and spinal alignment were measured and compared in both supine and upright positions. Mean scanning time was 43 min.
Results
All the considered parameters showed a statistically significant difference, except for lumbar lordotic angle. Mean percentage differences moving from supine to upright were +3.9 % for lumbar lordotic angle, +15 % for flavum ligament thickness, +16.2 % for sagittal disc bulge, −10.8 % for dural sac diameter, −13.1 % for spinal canal diameter, and −15.8 % for spinal canal area. In supine position, no patient presented with spondylolisthesis; moving to upright position, four patients showed spondylolisthesis (grade I).
Conclusion
Dynamic MR is a valuable diagnostic exam to analyze the structures involved in lumbar back pain due to spinal canal stenosis and spondylolisthesis; in supine position, relevant factors can be underestimated or hidden, becoming appreciable only patient standing upright. In this series, flavum ligament thickening presented a role comparable to disc bulge for narrowing of lumbar spinal canal.
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