0000000000280174
AUTHOR
Miguel Angel Reina
Nerve Root and Types of Needles Used in Transforaminal Injections
The use of transforaminal epidural injections of steroids is common practice in pain medicine, in patients with radicular pain resistant to conventional treatments such as physiotherapy or anti-inflammatory medications. The goal of these injections is to deposit steroids in the proximity of nerve roots, using the epidural or the transforaminal route. The procedure is performed using a translaminar, caudal, or transforaminal approach.
ESRA19-0618 Vulnerability of different nerves to intrafascicular injection with different needle bevel types and needle angles: a mathematical model
Background and aims Intrafascicular injection of a local anesthetic, its toxicity, and direct needle trauma to nerve tissue are generally considered the primary reasons for nerve injury after intraneural injection. We hypothesize that the only way that the local anesthetic can enter the fascicle is if at least 80% of the distal needle orifice is inside the fascicle. the aim of this study was to calculate the theoretical vulnerability of nerve fascicles given their actual sizes and that of different needle openings. Methods We superimposed microscopic images of two routinely used nerve block needles (a 22-G, 15 ‘StimuplexOD’ needleand a 22-G, 30 ‘StimuplexOUltra 360O’ needle) over microscopi…
Ultrastructure of the Perineurium
The perineurium is composed of multiple concentric single-cell layers enclosing individual nerve fascicles. Each layer has a thickness equivalent to the width of a perineurial cell. Groups of these cells join by means of tight junctions and desmosomes to form layers that function as a barrier against diffusion of particles across them. Perineurial internal layers have more of these specialized unions among perineurial cells, which are proximal to nerve fascicles.
Blocs nerveux périphériques, paresthésies et injections intraneurales
Resume Les fibres nerveuses, myelinisees ou non, sont disposees en faisceaux et entourees de plusieurs membranes l’endonerve, l’epinerve et la perinerve. La transmission de l’influx nerveux se fait de facon saltatoire d’un noeud de Ranvier a l’autre sur les fibres myelinisees et de facon continue sur les fibres non myelinisees. La compression ou le traumatisme d’un nerf produit une rafale de potentiels d’action que le patient interprete comme une paresthesie. Ce phenomene persiste tant que dure la lesion axonale. Les aiguilles a biseau court penetrent moins souvent la perinerve mais donne des lesions plus importantes dans ce cas. L’echoguidage montre que des injections intraneurales interfa…
Vulnerability of different nerves to intrafascicular injection by different needle types and at different approach angles: a mathematical model
Background and objectivesWe assume that intrafascicular spread of a solution can only occur if a large enough portion of the distal needle orifice is placed inside the fascicle. Our aim is to present and evaluate a mathematical model that can calculate the theoretical vulnerability of fascicles, analyzing the degree of occupancy of the needle orifice in fascicular tissue by performing simulations of multiple positions that a needle orifice can take inside a cross-sectional nerve area.MethodsWe superimposed microscopic images of two routinely used nerve block needles (22-gauge, 15° needle and 22-gauge, 30° needle) over the microscopic images of cross-sections of four nerve types photographed…
Ultrastructure of Dural Lesions Produced in Lumbar Punctures
During lumbar puncture, the insertion of a single-use, short-beveled spinal needle produces a “tent-like” effect. The dura-arachnoid lesions produced by this Quincke type of needles show a “crescent moon” shape resembling the letter “U” or “V” (similar to the lid of a can), with clean-cut edges. As the needle tip advances, the cut fragment is folded inwards, while all dural and arachnoid layers are entirely severed and the edges of the lesion are displaced inwardly. As soon as the spinal needle is withdrawn, the edges of the lesion tend to retract, owing to the viscoelastic properties of the affected dura mater.
Injections of Particulate Steroids for Nerve Root Blockade: Ultrastructural Examination of Complicating Factors
Selective nerve root block by a transforaminal approach with radiological control allows injection of an appropriate corticosteroid next to the nerve root, although it has been associated with major neurological complications in a few cases. There have been several reports in which corticosteroid injections performed at the level of the cervical or lumbar spine have led to severe spinal cord ischemic infarction. These have occurred independently of whether the procedure was performed under radiological control, in which the tip of the needle is identified to prevent vascular spreading of the solution injected.
Ultrastructure of Spinal Dura Mater
Pia mater is the innermost of the three meningeal membranes, closely surrounding the brain, the spinal cord, and the portion of spinal nerve roots extending towards their exit across the dura mater. A cellular layer and a subpial compartment shape the structure of the pia mater. The cellular layer is made up of flat, overlapping pial cells with amorphous, fundamental substance interposed among them. The surface of the cellular plane appears smooth and bright under scanning electron microscopy (SEM). Transmission electron microscopy shows that the cellular component is about three to five pial cells thick at the medullary level and two to three cells thick at the level of the nerve roots. Th…
Catheters in Regional Anesthesia
Anesthesiologists use different types of catheters in the performance of continuous regional anesthetic techniques such as epidural, subarachnoid, and paravertebral blocks, as well as peripheral nerve blocks.
Ultrastructure of Human Spinal Trabecular Arachnoid
The arachnoid trabecular layer, located internally to the arachnoid layer, is composed of fibers that form the spider web–like trabecular structure found in the subarachnoid space and in the adventitial layer of blood vessels. The arachnoid trabeculae give shape to tubular structures (arachnoid sheaths) for each nerve root and for the spinal cord. Some of these arachnoid trabeculae extend to the pia mater. The trabecular arachnoid is an extremely fragile structure, which can easily be damaged. Because of its fragility, this membrane may be destroyed during dissection and manipulation, so that it is not frequently seen or systematically described. Trabecular arachnoid limits nerve root movem…
3D interactive model of lumbar spinal structures of anesthetic interest
A 3D model of lumbar structures of anesthetic interest was reconstructed from human magnetic resonance (MR) images and embedded in a Portable Document Format (PDF) file, which can be opened by freely available software and used offline. The MR images were analyzed using a specific 3D software platform for biomedical data. Models generated from manually delimited volumes of interest and selected MR images were exported to Virtual Reality Modeling Language format and were presented in a PDF document containing JavaScript-based functions. The 3D file and the corresponding instructions and license files can be downloaded freely at http://diposit.ub.edu/dspace/handle/2445/44844?locale=en. The 3D…
Injection pressure mapping of intraneural vs. perineural injections: further lessons from cadaveric studies.
Background The aim of the study was to investigate the difference between intraneural and perineural injection pressures in human cadavers. Targeted nerves included the cervical roots, the supraclavicular and infraclavicular brachial plexus, the sciatic-subgluteal nerve and the common peroneal and tibial nerves. Methods Ten readings were obtained for each nerve location. Over ten seconds, 1 mL of 0.9% NaCl was injected - deliberately slower than in clinical practice to eliminate the risk of aberrant readings relating to the speed of injection. Perineural injections occurred at least 1 mm outside the epineurium. After pressure recordings were completed 0.1mL of dye was injected, and dissecti…