silicon and Peripheral-Nerve-Injuries

Up to 15% of combat trauma cases are accompanied by neuroinjuries with nerve gap formation that need to be bridged using various techniques and materials. Both with this prevalence of limb loss, especially traumatic amputations, tends to grow. Loosed limbs must be prosthetized by modern functional mind-controlled prosthesis based on nerve- or brain-computer interfaces. This study aimed at morphological evaluation of interaction between nerve fibers and silicon wires with different surface properties using peripheral nerve injury and grafting model. Experiment was performed on 50 male Wistar rats, weighing 180-250 g. Rats from experimental groups underwent sciatic nerve injury Sunderland 5 degree with a 10 mm gap formation that was subsequently filled with conduit consisting of decellularized aorta, carboxymethylcellulose gel and a set of longitudinally oriented p-type silicon wires 2-20 µm in diameter. We used silicon wires with native oxide in group Ia, with hydrogen-cleaned surface in group Ib and thermally grown oxide in group Ic. The gap in control groups was filled with decellularized aorta with gel alone (group II) or by autoneurograft (group III). 6 weeks postoperatively the conduit site was harvested and light microscopy performed. Implantation of conduit with native oxide on silicon wires surface resulted in more complete and equal neurotization of the conduit site with close adherence between the newly-formed nerve fibers and silicon wires, in comparison with groups where wires with other surface properties have been used. P-type silicon wires with native oxide are seems to be more suitable than other types of wires for further electrode preparation as a part of regenerative implants.

Topics: Animals; Disease Models, Animal; Male; Nerve Fibers; Nerve Regeneration; Peripheral Nerve Injuries; Prostheses and Implants; Rats, Wistar; Sciatic Nerve; Silicon; Surface Properties

To increase awareness of peripherally inserted central catheter (PICC) fracture and necessary nursing assessment to identify development of nerve injury after removal of the PICC fracture.. This is a case review of a cancer patient with fractured PICC and the postoperative symptoms leading to nerve injury.. The reason for PICC fracture is the fragility of silicon. Secondary surgical intervention of a PICC fragment resulted in nerve damage from a hematoma placing pressure on the median nerve in the arm.. It is necessary to use power injectable polyurethane PICCs. It is vital to have a clear understanding of signs and symptoms of nerve impingement in the arm when monitoring a post-operative patient. Assessment of neurological status, circulation, swelling and patient complaints of pain are all necessary functions of the nurse in caring for this type of patient.

Topics: Administration, Intravenous; Aged; Antineoplastic Combined Chemotherapy Protocols; Catheterization, Peripheral; Central Venous Catheters; Device Removal; Equipment Design; Equipment Failure; Female; Hematoma; Humans; Median Nerve; Peripheral Nerve Injuries; Recovery of Function; Silicon; Treatment Outcome; Ultrasonography, Doppler, Color; Ultrasonography, Interventional

Randomly aligned nerve cells in vitro on conventional culture substrata do not represent the complex neuronal network in vivo and neurites growing in uncontrolled manner may form neuroma. It is of great importance to mimic the organised growth pattern of nerve cells in the study of peripheral nerve repair. The aim of this work was to modify and optimize the photolithographic technique in creating a reusable template in the form of a silicon wafer that could be used to produce contact guidance on biodegradable polymer surface for the orientated growth of nerve cells. Micro-grooves (approximately 3 μm in depth) were etched into the silicon template using KOH at increased temperature. The originality of this work lies in the low cost and high efficiency method in producing microgrooves on the surface of biodegradable ultra-thin polymer substrates (50-100 μm), which can be readily rolled up to form clinically implantable nerve conduits. The design of a pattern with small ridge width (i.e., 5 μm) and bigger groove width (i.e., 20 μm) favored the alignment of cells along the grooves rather than on the ridges of the patterns, which minimized the effect of cross growing of neurites between adjacent grooves. Effectively, enhanced nerve regeneration could be anticipated from these patterned conduits.

Topics: Animals; Biocompatible Materials; Cell Line; Coated Materials, Biocompatible; Humans; Materials Testing; Microscopy, Atomic Force; Microscopy, Electron, Scanning; Nerve Regeneration; Neurons; Peripheral Nerve Injuries; Peripheral Nerves; Photography; Polymers; Schwann Cells; Silicon; Tissue Engineering; Tissue Scaffolds

It has been already demonstrated that thyroid hormone (T3) is one of the most important stimulating factors in peripheral nerve regeneration. We have recently shown that local administration of T3 in silicon tubes at the level of the transected rat sciatic nerve enhanced axonal regeneration and improved functional recovery. Silicon, however, cannot be used in humans because it causes a chronic inflammatory reaction. Therefore, in order to provide future clinical applications of thyroid hormone in human peripheral nerve lesions, we carried out comparative studies on the regeneration of transected rat sciatic nerve bridged either by biodegradable P(DLLA-(-CL) or by silicon nerve guides, both guides filled with either T3 or phosphate buffer. Our macroscopic observation revealed that 85% of the biodegradable guides allowed the expected regeneration of the transected sciatic nerve. The morphological, morphometric and electrophysiological analysis showed that T3 in biodegradable guides induces a significant increase in the number of myelinated regenerated axons (6862 +/- 1831 in control vs. 11799 +/- 1163 in T3-treated). Also, T3 skewed the diameter of myelinated axons toward larger values than in controls. Moreover, T3 increases the compound muscle action potential amplitude of the flexor and extensor muscles of the treated rats. This T3 stimulation in biodegradable guides was equally well to that obtained by using silicone guides. In conclusion, the administration of T3 in biodegradable guides significantly improves sciatic nerve regeneration, confirming the feasibility of our technique to provide a serious step towards future clinical application of T3 in human peripheral nerve injuries.

Topics: Absorbable Implants; Animals; Axons; Behavior, Animal; Cell Count; Cell Size; Electrophysiology; Humans; Microscopy, Electron; Nerve Fibers, Myelinated; Nerve Regeneration; Peripheral Nerve Injuries; Peripheral Nerves; Rats; Sciatic Nerve; Silicon; Thyroid Hormones; Triiodothyronine

This study was designed to investigate the potential for enhancement of peripheral nerve regeneration by the manipulation of the neural microenvironment with laminin-fibronectin solution (LF), dialyzed plasma (DP), collagen gel (CG), or phosphate buffered saline (PBS) in a silicon tubulization repair model.. A rat sciatic nerve model of injury and repair was used to study the effects of exogenous matrix precursors (contained in LF or DP), CG or PBS on nerve regeneration. A total of 50 Sprague-Dawley rats underwent left sciatic nerve transection and repair by silicon tubulization. The silicon tubules were either left empty (E), or filled with solutions of LF, DP, CG, or PBS. Nerve function was assessed preoperatively and then postoperatively, every 10 days for 90 days using sciatic functional indexes (SFI). On postoperative day 90, the sciatic nerves were harvested for histologic analysis and the posterior compartment muscles of each animal were harvested and weighed. Molecular analysis for two proteins associated with neural regeneration was performed on the nerve segments.. All five animal groups demonstrated equivalent functional recovery. Comparison of the rate of recovery and mean maximal recovery between each group revealed no statistically significant differences, with P-values ranging from 0.30 to 0.95. Posterior compartment muscle masses were similar in all groups except for LF, whose animals had muscle masses 8-9% lower than CG, PBS, or E (P < 0.05).. Alteration of the regenerating neural microenvironment with exogenous matrix precursors (LF, DP), CG or PBS failed to improve sciatic functional recovery after nerve transection and silicon tubulization in this model. From this study, we conclude that LF, DP, CG, and PBS do not enhance the rate or degree of recovery of peripheral nerve function across a narrow gap when nerves are repaired by silicon tubulization.

Topics: Animals; Collagen; Culture Media, Conditioned; Fibronectins; Laminin; Male; Muscle, Skeletal; Nerve Regeneration; Nerve Transfer; Peripheral Nerve Injuries; Peripheral Nerves; Phosphates; Plasma; Prostheses and Implants; Rats; Rats, Sprague-Dawley; Sciatic Nerve; Silicon