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PubMed1995

Possible lateralization of peripheral nerve conduction associated with gender.

Lateralization of peripheral nerve conduction velocity was studied in right-handed men (n = 40) and women (n = 48). Sensory and motor velocities were measured in ulnar and median nerves of the right and left hands. In women, the mean sensory velocity was significantly faster in the left than the right hand. There were no significant right-left differences in men. The mean sensory velocity from the right hand was significantly slower in women than men, creating an asymmetric organization of sensory conduction in women. Estradiol in women and testosterone in men were suggested as playing a role in asymmetric and symmetric nerve conductions, respectively.

Adult↗
PubMedDate not supplied

Guillain-Barré syndrome: an ultrastructural study of peripheral nerve in 65 patients.

65 biopsies of peripheral nerve from patients suffering from Guillain-Barré syndrome were studied by electron microscopy. In 48 cases there was macrophagic invasion of the Schwann cells of certain myelinated fibers, and in 32 of these cases some myelin sheaths were stripped away by an elongated macrophagic process. Vesicular disruption of the myelin sheath was observed in only 8 cases and in less than 1% of the myelinated fibers. Uncompacted myelin lamellae were observed in a few myelinated fibers. These ultrastructural lesions are analysed and commented on with a view to selecting patients who are to undergo plasma exchange.

Biopsy↗
PubMedDate not supplied

Histology of the peripheral nerve trunks.

The anatomic structure of the peripheral nerve trunks is briefly reviewed. The nerve fibers are divided into myelinated and non-myelinated fibers and in the limbs they are composed of motor, sensory, and sympathetic fibers. On functional grounds the fibers are considered either efferent or afferent. The general scheme of vascular supply to the nerve fibers is described.

Connective Tissue↗
PubMed1991

Peripheral nerve regeneration is impeded by interleukin-1 receptor antagonist released from a polymeric guidance channel.

Interleukin-1 receptor antagonist (IL-1ra), a true antagonist of the interleukin-1 (IL-1) receptors, is released by activated macrophages and binds specifically to the IL-1 receptors without triggering IL-1 effects. Following peripheral nerve axotomy, activated macrophages release IL-1, which induces the expression of nerve growth factor (NGF) mRNA in Schwann cells. IL-1ra may therefore impede peripheral nerve regeneration by blocking the NGF-mediated effect of IL-1. Peripheral nerve regeneration occurring through polymeric guidance channels releasing IL-1ra was investigated in a 4-mm gap transected mouse sciatic nerve model. Cohorts of five animals were implanted with tubes releasing either bovine serum albumin (BSA), BSA with IL-1ra, or BSA with deactivated IL-1ra (dIL-1ra) for 4 weeks. In vitro release kinetics indicated that after an initial burst, IL-1ra release was linear for the next 3 1/2 weeks. Following implantation of a polymeric guidance channel, a regenerated cable bridged the nerve gap in all animals. The cables were similar in size and were composed of nerve microfascicles containing both unmyelinated and myelinated axons in association with their Schwann cells. Tissue regenerated in tubes releasing BSA-IL-1ra contained, however, significantly fewer myelinated and unmyelinated axons and blood vessels than did tubes releasing BSA alone or BSA-dIL-1ra. We conclude that a naturally occurring antagonist of IL-1 receptors impedes peripheral nerve regeneration, suggesting that macrophages play an essential role in controlling peripheral nerve regeneration through the release of stimulatory and/or inhibitory molecules.

Animals↗
PubMed2005

Continuous peripheral nerve blocks at home for treatment of recurrent complex regional pain syndrome I in children.

BACKGROUND: Recurrent complex regional pain syndrome I is not rare in the pediatric population. The authors conducted this study to evaluate the efficacy of continuous peripheral nerve blocks with elastomeric disposable pumps associated with initial Bier blocks for the treatment of recurrent complex regional pain syndrome I in children. METHODS: After parental informed consent, 13 children who did not respond to conventional complex regional pain syndrome treatment were included (mean age, 13 yr; range, 9-16 yr). After general anesthesia, peripheral nerve block was performed using 0.5 ml/kg lidocaine, 1%, with epinephrine and 0.5% ropivacaine injected in the peripheral nerve block catheter. Then, a 20-min Bier block was performed using a tourniquet and 0.2 ml/kg lidocaine, 1%; 3 ml/kg hydroxyethyl starch 130/06; and 5 mg/kg buflomedil injected intravenously. A solution of 0.1 ml . kg . h continuous ropivacaine, 0.2%, was infused through the catheter using an elastomeric pump for 96 h. Need for rescue analgesia, occurrence of side effects, and status of motor and sensory block were recorded at hours 1, 6, 12, 24, 48, 72, and 96. Children and parents completed a satisfaction assessment. All of the children had follow-up visits after 2 months. RESULTS: Postoperative analgesia was excellent. The median pain score was 0 for each period studied. Motor blockade was minimal before 12 h (median, 1) and absent thereafter. One child needed rescue analgesia. All children were able to walk easily after the initial 24-h period (walking score, > 4). Children and parents were all satisfied. Children returned home under parental surveillance beginning in the 24th hour. Neither peripheral nerve block nor Bier block caused side effects. After 2 months, none of the children exhibited any clinical symptom of recurrent complex regional pain syndrome. CONCLUSION: Ambulatory continuous peripheral nerve block associated with an initial Bier block seems to be a significant and novel contribution to treat recurrent pediatric complex regional pain syndrome I. It allows complete pain relief, early mobilization, and rapid return home, representing a psychological advantage for these children.

Adolescent↗
PubMed2002

Radiofrequency treatment of peripheral nerves.

Treatment of chronic refractory pain in which peripheral nerves are involved has proven to be difficult. Neurolysis by surgical, chemical, cryogenic, or thermal means may be considered as an option on seldom occasions, because of the risk of neuritis and deafferentation pain, motor deficit, and potential unintentional damage to nontargeted tissue. To our knowledge, there is only 1 report concerning selective radiofrequency (RF) treatment of the obturator and femoral nerves that was published. The introduction of the non-neurodestructive pulsed radiofrequency technique has provided new possibilities for the treatment of peripheral nerves. Today there is some experience with the management of chronic shoulder pain and additional case reports on other indications.

Journal Article↗
PubMed2006

Myelination and nodal formation of regenerated peripheral nerve fibers following transplantation of acutely prepared olfactory ensheathing cells.

Transplantation of olfactory ensheathing cells (OECs) into injured spinal cord results in improved functional outcome. Mechanisms suggested to account for this functional improvement include axonal regeneration, remyelination and neuroprotection. OECs transplanted into transected peripheral nerve have been shown to modify peripheral axonal regeneration and functional outcome. However, little is known of the detailed integration of OECs at the transplantation site in peripheral nerve. To address this issue, cell populations enriched in OECs were isolated from the olfactory bulbs of adult green fluorescent protein (GFP)-expressing transgenic rats and transplanted into a sciatic nerve crush lesion which transects all axons. Five weeks to 6 months after transplantation, the nerves were studied histologically. GFP-expressing OECs survived in the lesion and distributed longitudinally across the lesion zone. The internodal regions of individual teased fibers distal to the transection site were characterized by GFP expression in the cytoplasmic and nuclear compartments of cells surrounding the axons. Immunoelectron microscopy for GFP indicated that the transplanted OECs formed peripheral type myelin. Immunostaining for sodium channel and Caspr revealed a high density of Na(v)1.6 at the newly formed nodes of Ranvier which were flanked by paranodal Caspr staining. These results indicate that transplanted OECs extensively integrate into transected peripheral nerve and form myelin on regenerated peripheral nerve fibers, and that nodes of Ranvier of these axons display proper sodium channel organization.

Animals↗
PubMed1996

Peripheral nerve vascular changes in spontaneously hypertensive rats.

Circulation to the brain is affected by hypertension. Hypertension-dependent cerebrovascular changes were documented primarily in brain pial arteries, whereas no information is so far available concerning changes of peripheral nerve vascularization in hypertension. This study was designed to assess the occurrence of structural changes of interfascicular and intrafascicular arteries supplying peripheral nerves (the so called vasa nervorum) in spontaneously hypertensive rats (SHR). The investigation was performed in 8-month-old SHR, by using standard microanatomical techniques associated with quantitative image analysis. In SHR a significant increase of systolic pressure values accompanied by thickening of the arterial wall, narrowing of the lumen and increase of the wall-to-lumen ratio were observed in comparison with age-matched normotensive Wistar-Kyoto rats. Hypertension-related structural changes involved primarily interfascicular arteries and to a lesser extent intrafascicular arteries. These findings indicate that similarly as documented for cerebral arteries, the vascular supply to peripheral nerves is impaired in hypertension. Structural changes of interfascicular and intrafascicular arteries of SHR could lead to ischemia of peripheral nerves. Further work is in progress to evaluate the functional relevance of hypertensive changes to peripheral nerve vasculature.

Animals↗
PubMed1998

Recovery of C-fiber-induced extravasation following peripheral nerve injury in the rat.

Peripheral nerve injury leads to substantial alterations in injured sensory neurons. These include cell death, phenotypic modifications, and regeneration. Primary sensory neurons have recently been shown not to die until a time beyond 4 months following a nerve crush or ligation and this loss is, moreover, limited to cells with unmyelinated axons, the C-fibers. The late loss of C-fibers may be due to a lack of target reinnervation during the regenerative phase. In order to investigate this, we have used a particular peripheral function, unique to C-fibers, as a measure of peripheral reinnervation: an increase in capillary permeability on antidromic activation of C-fibers, i.e., neurogenic extravasation. This was investigated in rats that had received a nerve crush injury 1 to 50 weeks earlier. Some recovery of the capacity of C-fibers to generate extravasation was detected at 8-10 weeks, which increased further at 12-14 weeks, and then plateaued at this level with no further recovery at 30 or 50 weeks. In intact and damaged sciatic nerves, A beta-fibers never induced extravasation. These findings are compatible with the hypothesis that those C-fibers which make it back to their peripheral targets do not subsequently die and those that do not, may die.

Animals↗
PubMed1999

[The emergent repair of peripheral nerve injury of the wrist].

OBJECTIVE: To investigate the effect of the emergent repair of peripheral nerve injury of the wrist. METHODS: From July 1993 to December 1997, 17 cases were admitted, which 21 injured peripheral nerves were repaired emergently. Among them, there were 11 cases of median nerve injury, 2 cases of ulnar nerve injury and 4 cases of median and ulnar nerve injury. All the nerves were ruptured completely except one which was partially ruptured. The emergent operation was taken and the injured nerves were repaired by microsurgical technique. RESULTS: Followed up 6 to 18 months after operation, 95.25% injured nerves had good outcome. CONCLUSION: Because of the specific structure of the wrist, nerve injury at this part need to be repaired emergently. It can enhance the regeneration of the injured nerve, preserve the function of the intrinsic muscle of hand, and decrease the local adhesion.

Adolescent↗
PubMed2003

Local regulation of fat metabolism in peripheral nerves.

We comprehensively analyzed gene expression during peripheral nerve development by performing microarray analyses of premyelinating, myelinating, and postmyelinating mouse sciatic nerves, and we generated a database of candidate genes to be tested in mapped peripheral neuropathies. Unexpectedly, we identified a large cluster of genes that are (1) maximally expressed only in the mature nerve, after myelination is complete, and (2) tied to the metabolism of storage (energy) lipids. Many of these late-onset genes are expressed by adipocytes, which we find constitute the bulk of the epineurial compartment of the adult nerve. However, several such genes, including SREBP-1, SREBP-2, and Lpin1, are also expressed in the endoneurium. We find that Lpin1 null mutations lead to lipoatrophy of the epineurium, and to the dysregulation of a battery of genes required for the regulation of storage lipid metabolism in both the endoneurium and peri/epineurium. Together with the observation that these mutations also result in peripheral neuropathy, our findings demonstrate a crucial role for local storage lipid metabolism in mature peripheral nerve function, and have important implications for the understanding and treatment of peripheral neuropathies that are commonly associated with metabolic diseases such as lipodystrophy and diabetes.

Adipocytes↗
PubMed1989

Therapeutic strategies in promoting peripheral nerve regeneration.

Currently, regeneration chambers, adrenocorticotropic hormone (ACTH) and related peptides, and gangliosides appear to be the most promising therapies in the promotion of peripheral nerve regeneration, growth, and repair. Regeneration chambers enhance rat sciatic nerve regeneration in vivo after transection by providing a structurally organized and protected preformed space within which nerve fibers are exposed to macromolecular compounds which direct and enhance nerve growth. ACTH and related peptides, independent of their corticotropic activities, increase the availability of structural proteins to the axon terminal in rats subjected to nerve crush injuries and demonstrate inotropic effects in adrenalectomized and/or hypophysectomized rats. Exogenously administered gangliosides promote neuronal sprouting, regeneration, and reinnervation in experimental situations and have undergone clinical testing in acute and chronic peripheral nerve disorders. At the current dosage levels and schedules, the clinical results of ganglioside therapy have been mixed. The success of the experimental studies supports further clinical testing of these therapies in peripheral nerve disorders.

Adrenocorticotropic Hormone↗
PubMed1994

Dystroglycan is a binding protein of laminin and merosin in peripheral nerve.

alpha-Dystroglycan, a 156 kDa dystrophin-associated glycoprotein, binds laminin in skeletal muscle. Here we demonstrate that alpha-dystroglycan is a binding protein of laminin (A/B1/B2) and merosin (M/B1/B2) in peripheral nerve. Immunocytochemical analysis demonstrates the localization of alpha-dystroglycan and merosin surrounding myelin sheath of peripheral nerve fibers. Biochemical analysis demonstrates that the 120 kDa peripheral nerve alpha-dystroglycan binds merosin as well as laminin. The binding of laminin and merosin is Ca2+ dependent and is inhibited by NaCl and heparin. Recently, merosin was shown to be deficient in the peripheral nerve of dy mice which have defects in myelination. The interaction between alpha-dystroglycan and merosin may play a role in the regulation of Schwann cell myelination and/or maintenance of myelin sheath.

Animals↗
PubMed2000

Comparison of spinal cord evoked potentials and peripheral nerve evoked potentials by electric stimulation of the spinal cord under acute spinal cord compression in cats.

STUDY DESIGN: Spinal cord evoked potentials and peripheral nerve evoked potentials after spinal cord stimulation were recorded under acute spinal cord compression in 19 cats. OBJECTIVES: To investigate the effects of acute compression upon grey matter and white matter by comparing both potentials. METHODS: We compared peripheral nerve evoked potentials, recorded at the biceps brachii branch of the musculocutaneous nerve, with descending spinal cord evoked potentials, recorded from the lumbar spinal cord, by stimulation to the C2 level, under compression of the C6 segment. RESULTS: The amplitude of both potentials decreased with increased compression. The second wave of peripheral nerve evoked potentials, which are motor fibre action potentials, decreased sooner than those of the spinal cord evoked potentials. CONCLUSION: These findings indicate that peripheral nerve evoked potentials are sensitive to acute damage of the segmented compression. This suggests that grey matter is more vulnerable to compression than white matter.

Animals↗
PubMed2004

Effects of peripheral nerve injury on delta opioid receptor (DOR) immunoreactivity in the rat spinal cord.

Morphine and other opioids have direct analgesic actions in the spinal cord and chronic spinal administration of opioid agonists is used clinically in patients suffering from severe, chronic pain. Neuropathic pain resulting from peripheral nerve injury is often less sensitive to opioid therapy than other forms of chronic pain in both humans and animal models. Changes in spinal mu-opioid receptor (MOR) expression have been demonstrated in animal models of neuropathic pain. However, these changes alone fail to account for the attenuation of opioid activity. Reduced expression of delta-opioid receptors (DOR) following peripheral nerve injury has been reported but most of these reports are limited to subjective observation. The magnitude and consistency of these changes is therefore unclear. In addition, previous studies did not evaluate the effects of nerve injury on behavioral measures to confirm induction of aberrant pain symptoms. We therefore performed quantitative image analysis to evaluate the effect of peripheral nerve injury on DOR-immunoreactivity in spinal cord sections from rats previously characterized for sensory responsiveness. We observed statistically significant decreases ipsilateral to nerve injury in all three models tested: sciatic nerve transection, chronic constriction injury of the sciatic nerve and L5/L6 spinal nerve ligation. These results suggest that decreases in the expression of DOR are a common feature of peripheral nerve injury.

Afferent Pathways↗
PubMed1996

[Rehabilitation of war injuries associated with peripheral nerve lesions].

The objective of this study was to examine frequency, characteristics and results of hospital medical rehabilitation of war injured patients with peripheral nerve lesions. War injured patients with peripheral nerve lesions make 10.83% of all war injured hospitalized patients. The major etiologic factor in these injuries were firearms. Most injured aged 26 to 36 years of age, whereas men were injured more often than women. The injuries were primarily localized in the regions of axilla, upper leg and upper arm. In regard to upper extremities injuries most often occurred on the right side or bilaterally. Injuries of n. ischiadicus, combination of n. ulnaris and n. medianus occurred more frequently than injuries of other peripheral nerves. Electromyoneurographic and neurosurgical findings point to frequent partial-severe and complete nerve lesions. After hospital treatment lasting 4.6 months on the average, unsatisfactory functional reparation was found in most injured patients. This demands further control, continuous medical as well as social and professional rehabilitation.

Adult↗
PubMed1986

Peripheral nerve surgery--today and looking ahead.

The trend in peripheral nerve surgery is toward earlier definitive treatment of the lesion, based on the optimal use of preoperative and intraoperative electrodiagnostic techniques. Newer diagnostic tools include computed tomography (CT) and thermography. Knowledge is still being gained about the technology and limitations of the autogenous nerve grafts that are being used to overcome nerve gaps. The technique of nerve anastomosis is undergoing rapid improvement, and better methods have been developed for identifying motor and sensory fascicles at the time of operation. Research activity into the problem of nerve damage produced at the time of trimming nerve stumps promises to change to the technology of nerve repair in the near future. For benign nerve sheath tumors (schwannoma, neurofibroma), the trend is away from nerve excision and in the direction of tumor enucleation. Histologic methods for diagnosing malignant nerve tumors have been improved, making it possible to embark on radical excision with less hesitation. The pain syndromes (causalgia, phantom limb pain, and stump pain) that may follow nerve injury continue to present a problem in management, but steady progress is being made toward a rational program of management. A more distant prospect is for pharmacologic and electrophysiologic methods to accelerate axonal regeneration.

Carpal Tunnel Syndrome↗
PubMedDate not supplied

Continuous peripheral nerve blocks with stimulating catheters.

BACKGROUND AND OBJECTIVES: This study evaluated the efficacy of stimulating catheters used for continuous peripheral nerve blocks as a means of immediate verification and confirmation of correct catheter position. METHODS: This observational study presents our experience with 130 stimulating catheters used in 40 intersternocleidomastoid, 24 axillary, 47 femoral, and 19 lateral midfemoral sciatic nerve blocks. Placement characteristics (amperage, depth of introducer needle or catheter insertion, elicited motor responses), subsequent postoperative analgesia, and catheter position evaluated with the radiopaque dye analysis were all studied. RESULTS: Except in femoral blocks, characteristics of motor responses elicited (1 Hz, 0,1 ms) by the introducer assembly and catheter differed. The amperage required to elicit motor responses typically was higher with the catheter than with the introducer needle (1.6 [0.2 to 4 mA] v 0.5 [0.4 to 1 mA] P <.0001). The ability to elicit a motor response with the stimulating catheter correlated with successful clinical anesthesia in 124 cases. Opacified radiography showed no aberrant position in these cases. Three catheters for upper limb block failed to stimulate, provided poor anesthesia, and had radiologic evidence of aberrant position. Even though they failed to stimulate, 3 catheters for sciatic block functioned well, and the opacified radiography showed correct position. CONCLUSION: The ability to electrostimulate nerves using an in situ catheter increases success rate in catheter placement for continuous peripheral nerve blocks. Further controlled investigations are necessary to compare this technique with more conventional methods in terms of cost and utility for various peripheral nerve blocks.

Adult↗