-
Journal of Anatomy Jan 2005Rat sural nerve is widely used in experimental studies investigating injury and regeneration of the peripheral nervous system. However, it has not yet been established...
Rat sural nerve is widely used in experimental studies investigating injury and regeneration of the peripheral nervous system. However, it has not yet been established whether morphological and morphometric parameters differ within corresponding levels of the rat sural nerve. The aims of the present study were to investigate the normal morphological and morphometric aspects of the sural nerve in postnatal developing female rats, with special attention to longitudinal morphology and lateral symmetry. Rats aged 30, 90 and 180 days were killed, and proximal and distal segments of the right and left sural nerves were prepared for light microscopy and morphometric study. No differences were found between the proximal and distal segments or between the right and left sides at the same levels. In addition, postnatal growth continuously and symmetrically affected the sural nerve fascicles and myelinated fibres. Fibre population distribution was also affected by increasing body weight; distribution was unimodal at 30 days, and by 180 days this distribution was established as bimodal. We concluded that the sural nerve is long and constant in its morphology and presents a continuous and symmetrical growth, more pronounced between 30 and 90 days of age, thus providing a good model for experimental neuropathies.
Topics: Aging; Animals; Body Weight; Female; Nerve Fibers; Rats; Rats, Wistar; Sural Nerve
PubMed: 15679874
DOI: 10.1111/j.0021-8782.2005.00368.x -
Journal of Neurochemistry Mar 2021Patients with transthyretin (TTR)-type familial amyloid polyneuropathy (FAP) typically exhibit sensory dominant polyneuropathy and autonomic neuropathy. However, the...
Patients with transthyretin (TTR)-type familial amyloid polyneuropathy (FAP) typically exhibit sensory dominant polyneuropathy and autonomic neuropathy. However, the molecular pathogenesis of the neuropathy remains unclear. In this study, we characterize the features of FAP TTR the substitution of lysine for glutamic acid at position 61 (E61K). This FAP was late-onset, with sensory dominant polyneuropathy, autonomic neuropathy, and cardiac amyloidosis. Interestingly, no amyloid deposits were found in the endoneurium of the four nerve specimens examined. Therefore, we examined the amyloidogenic properties of E61K TTR in vitro. Recombinant wild-type TTR, the substitution of methionine for valine at position 30 (V30M) TTR, and E61K TTR proteins were incubated at 37°C for 72 hr, and amyloid fibril formation was assessed using the thioflavin-T binding assay. Amyloid fibril formation by E61K TTR was less than that by V30M TTR, and similar to that by wild-type TTR. E61K TTR did not have an inhibitory effect on neurite outgrowth from adult rat dorsal root ganglion (DRG) neurons, but V30M TTR did. Furthermore, we studied the sural nerve of our patient by terminal deoxynucleotidyl transferase dUTP nick end labeling and electron microscopy. A number of apoptotic cells were observed in the endoneurium of the nerve by transferase dUTP nick end labeling. Chromatin condensation was confirmed in the nucleus of non-myelinating Schwann cells by electron microscopy. These findings suggest that E61K TTR is low amyloidogenic, in vitro and in vivo. However, TTR aggregates and amyloid fibrils in the DRG may cause sensory impairments in FAP because the DRG has no blood-nerve barrier. Moreover, Schwann cell apoptosis may contribute to the neurodegeneration.
Topics: Amino Acid Substitution; Amyloid; Amyloid Neuropathies, Familial; Amyloidosis; Animals; Apoptosis; Crystallography, X-Ray; Humans; Mutation; Peripheral Nerves; Plaque, Amyloid; Prealbumin; Rats; Rats, Wistar; Recombinant Proteins; Schwann Cells; Sural Nerve
PubMed: 32852783
DOI: 10.1111/jnc.15162 -
Orthopaedics & Traumatology, Surgery &... Feb 2015The risk of damage to cutaneous sensory nerves located near portals has been evaluated for both conventional arthroscopy and extra-articular posterior ankle endoscopy....
BACKGROUND
The risk of damage to cutaneous sensory nerves located near portals has been evaluated for both conventional arthroscopy and extra-articular posterior ankle endoscopy. The objective of the anatomic study reported here was to assess the risk of injury to the sural nerve or lateral calcaneal nerve while using the distal lateral portal for the Achilles tendinoscopy procedure described by Vega et al. in 2008.
MATERIALS AND METHODS
We dissected the sural nerve and its branch, the lateral calcaneal nerve, of 13 human cadaver ankles in the prone position. We defined P as the point where the Achilles peritendon was opened during the distal lateral approach used for the study technique. P was adjacent to the lateral edge of the Achilles tendon, 2 cm proximal to the postero-superior edge of the calcaneal tuberosity. T was defined as the attachment site of the most lateral fibres of the Achilles tendon to the postero-superior edge of the calcaneal tuberosity. We evaluated the origin of the lateral calcaneal nerve relative to T and we measured the shortest distances separating P from the sural nerve and lateral calcaneal nerve.
RESULTS
A lateral calcaneal nerve was identified in 10 (77%) ankles and originated a mean of 39.1mm (range, 25.0-65.0mm) proximal to T. P was at a mean distance from the sural nerve of 12.3mm (range, 5.0-18.0mm) and from the lateral calcaneal nerve of 6.8mm (range, 4.0-9.0mm). The median difference between these two distances was statistically significant (P=0.002).
DISCUSSION
While using the distal lateral portal for Achilles tendinoscopy, the lateral calcaneal nerve is at greater risk for injury than is the sural nerve.
LEVEL OF EVIDENCE
Level IV. Anatomic Study.
Topics: Achilles Tendon; Arthroscopy; Cadaver; Female; Humans; Intraoperative Complications; Male; Peripheral Nerve Injuries; Sural Nerve
PubMed: 25595430
DOI: 10.1016/j.otsr.2014.10.019 -
Medicine Oct 2019There is no consensus regarding the references to determine the exact location of the skin incision to minimize iatrogenic sural nerve injury in the sinus tarsi approach...
There is no consensus regarding the references to determine the exact location of the skin incision to minimize iatrogenic sural nerve injury in the sinus tarsi approach for calcaneal fracture.The purpose of this cadaveric study was to describe the anatomical course of the sural nerve in relation to easily identifiable landmarks during the sinus tarsi approach and to provide a more practical reference for surgeons to avoid sural nerve injury.Twenty-four foot and ankle specimens were dissected. The bony landmarks used in the following reference points were the tip of the lateral malleolus (point A), lateral border of the Achilles tendon on the collinear line with point A (point B), posteroinferior apex of the calcaneus (point C), inferior margin of the calcaneus on the plumb line through point A (point D), and tip of the fifth metatarsal base (point E). After careful dissection, the distances of the sural nerve to points A and B in the horizontal direction (lines D1 and D2), points A and C in the diagonal direction (lines D3 and D4), points A and D in the vertical direction (lines D5 and D6), and points A and E in the diagonal direction (lines D7 and D8) were measured.The median ratio of D1 to D1+D2, D3 to D3+D4, D5 to D5+D6, and D7 to D7+D8 were 0.37 (range, 0.26-0.50), 0.23 (range, 016-0.33), 0.35 (range, 0.25-0.45), and 0.32 (range, 0.20-0.45), respectively.The distance ratios from this study can be helpful to avoid sural nerve injury during the sinus tarsi approach for calcaneal fractures. Established standard incision may have to be modified to minimize sural nerve injury.
Topics: Aged; Aged, 80 and over; Ankle Injuries; Cadaver; Calcaneus; Female; Fracture Fixation, Internal; Fractures, Bone; Humans; Intraoperative Complications; Male; Middle Aged; Peripheral Nerve Injuries; Sural Nerve; Tarsal Bones
PubMed: 31626138
DOI: 10.1097/MD.0000000000017611 -
Quarterly Journal of Experimental... Sep 1989Selective electrical stimulation of the non-myelinated C fibres of the sural nerve in the decerebrated, spinalized rabbit evoked long-latency (76-160 ms), long-lasting...
Selective electrical stimulation of the non-myelinated C fibres of the sural nerve in the decerebrated, spinalized rabbit evoked long-latency (76-160 ms), long-lasting (greater than 100 ms) reflex responses in the ipsilateral ankle extensor gastrocnemius medialis (GM). Activation of the same fibres elicited little or no response from the ipsilateral knee flexor semitendinosus (ST). Reflex responses were evoked in both GM and ST muscle nerves by stimulation of the A beta afferents of the sural nerve. The A beta-elicited reflex in GM was enhanced, and that in ST depressed by prior activation of sural nerve C fibres. Strychnine, but not picrotoxin or mecamylamine, blocked C fibre-induced inhibition of the flexor reflex. Pinching the heel with serrated forceps produced an immediate reflex discharge in GM motoneurones, whereas ST responded upon termination of the stimulus. Pinching the second toe evoked reflex activity in ST but not in GM. After strychnine (0.5 mg kg-1), both sets of motoneurones responded simultaneously to stimulation of either the heel or the toe. These data show that sural and other afferent fibres from the heel excite ipsilateral GM motoneurones and inhibit ST reflex responses. One interpretation of these findings is that fine sural afferents activate parallel inhibitory and excitatory pathways, of which the former is sensitive to strychnine and therefore probably mediated by glycine.
Topics: Afferent Pathways; Animals; Electric Stimulation; Motor Neurons; Nerve Fibers; Nerve Fibers, Myelinated; Physical Stimulation; Rabbits; Reflex; Spinal Nerves; Strychnine; Sural Nerve
PubMed: 2594929
DOI: 10.1113/expphysiol.1989.sp003320 -
Clinical Imaging 2014To develop a diffusion tensor imaging (DTI) protocol for assessing the sural nerve in healthy subjects.
OBJECTIVE
To develop a diffusion tensor imaging (DTI) protocol for assessing the sural nerve in healthy subjects.
METHODS
Sural nerves in 25 controls were imaged using DTI at 3T with 6, 15, and 32 gradient directions. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were computed from nerve regions of interest co-registered with T2-weighted images.
RESULTS
Coronal images with 0.5(RL)× 2.0(FH)× 0.5(AP)mm(3) resolution successfully localized the sural nerve. FA maps showed less variability with 32 directions (0.559 ± 0.071) compared to 15(0.590 ± 0.080) and 6(0.659 ± 0.109).
CONCLUSIONS
Our DTI protocol was effective in imaging sural nerves in controls to establish normative FA/ADC, with potential to be used non-invasively in diseased nerves of patients.
Topics: Adult; Anisotropy; Diffusion Tensor Imaging; Female; Healthy Volunteers; Humans; Male; Reproducibility of Results; Sural Nerve
PubMed: 24908367
DOI: 10.1016/j.clinimag.2014.04.008 -
PloS One 2013Recently, vagus nerve preservation or reconstruction of vagus has received increasing attention. The present study aimed to investigate the feasibility of reconstructing...
BACKGROUND
Recently, vagus nerve preservation or reconstruction of vagus has received increasing attention. The present study aimed to investigate the feasibility of reconstructing the severed vagal trunk using an autologous sural nerve graft.
METHODS
Ten adult Beagle dogs were randomly assigned to two groups of five, the nerve grafting group (TG) and the vagal resection group (VG). The gastric secretion and emptying functions in both groups were assessed using Hollander insulin and acetaminophen tests before surgery and three months after surgery. All dogs underwent laparotomy under general anesthesia. In TG group, latency and conduction velocity of the action potential in a vagal trunk were measured, and then nerves of 4 cm long were cut from the abdominal anterior and posterior vagal trunks. Two segments of autologous sural nerve were collected for performing end-to-end anastomoses with the cut ends of vagal trunk (8-0 nylon suture, 3 sutures for each anastomosis). Dogs in VG group only underwent partial resections of the anterior and posterior vagal trunks. Laparotomy was performed in dogs of TG group, and latency and conduction velocity of the action potential in their vagal trunks were measured. The grafted nerve segment was removed, and stained with anti-neurofilament protein and toluidine blue.
RESULTS
Latency of the action potential in the vagal trunk was longer after surgery than before surgery in TG group, while the conduction velocity was lower after surgery. The gastric secretion and emptying functions were weaker after surgery in dogs of both groups, but in TG group they were significantly better than in VG group. Anti-neurofilament protein staining and toluidine blue staining showed there were nerve fibers crossing the anastomosis of the vagus and sural nerves in dogs of TG group.
CONCLUSION
Reconstruction of the vagus nerve using the sural nerve is technically feasible.
Topics: Abdomen; Action Potentials; Animals; Dogs; Gastric Emptying; Sural Nerve; Transplants; Vagus Nerve
PubMed: 23555604
DOI: 10.1371/journal.pone.0058903 -
Brain and Behavior Aug 2016Tick-borne encephalitis (TBE) is an emerging flaviviral zoonosis in Central and Eastern Europe. TBE can present as meningitis, meningoencephalitis, or...
OBJECTIVES
Tick-borne encephalitis (TBE) is an emerging flaviviral zoonosis in Central and Eastern Europe. TBE can present as meningitis, meningoencephalitis, or meningoencephalomyelitis. Dysfunction of the autonomic (ANS) and peripheral motoric and sensory nervous system (PNS) might contribute to acute and long-term complications. We aimed to examine, whether the ANS and PNS are affected in acute TBE.
METHODS
Fourteen patients with acute TBE, 17 with diabetic polyneuropathy (d-PNP), and 30 healthy controls (HC) were examined in our single-center, prospective study. ANS and PNS function was assessed by time- and frequency-domain parameters of the heart rate (HR) variability at rest and deep respiration, and by sural and tibial nerve neurography. Primary endpoint was the HR variability at rest measured by root mean square of the successive differences (RMSSD). Autonomic symptoms and quality of life (QoL) were assessed by questionnaires.
RESULTS
Tick-borne encephalitis patients had a lower RMSSD at rest (TBE 13.1 ± 7.0, HC 72.7 ± 48.3; P < 0.001) and deep respiration (TBE 42.8 ± 27.0, HC 109.7 ± 68.8; P < 0.01), an increased low-frequency to high-frequency power component ratio at rest (TBE 4.0 ± 4.0, HC 0.8 ± 0.5; P < 0.001), and a higher minimal heart rate at rest (TBE 85.4 ± 7.0, HC 69.5 ± 8.5; P < 0.001), all similar to patients with d-PNP, indicating sympathovagal imbalance with increased sympathetic activation. Compared to HC, sural and tibial nerve conduction velocities and action potential amplitudes were reduced, ANS symptoms were more frequent, and QoL was lower in patients with TBE.
CONCLUSIONS
The ANS and to a lesser degree the PNS are affected by acute TBE, which could potentially contribute to short- and long-term morbidity.
Topics: Adult; Aged; Autonomic Nervous System Diseases; Diabetic Neuropathies; Encephalitis, Tick-Borne; Female; Heart Rate; Humans; Male; Middle Aged; Neural Conduction; Peripheral Nervous System Diseases; Quality of Life; Respiration; Sural Nerve; Tibial Nerve; Valsalva Maneuver; Young Adult
PubMed: 27247855
DOI: 10.1002/brb3.485 -
Journal of Neurophysiology May 2013During human walking, precise coordination between the two legs is required in order to react promptly to any sudden hazard that could threaten stability. The networks...
During human walking, precise coordination between the two legs is required in order to react promptly to any sudden hazard that could threaten stability. The networks involved in this coordination are not yet completely known, but a direct spinal connection between soleus (SOL) muscles has recently been revealed. For this response to be functional, as previously suggested, we hypothesize that it will be accompanied by a reaction in synergistic muscles, such as gastrocnemius lateralis (GL), and that a reversal of the response would occur when an opposite reaction is required. In the present study, surface EMGs of contralateral SOL and GL were analyzed after tibial nerve (TN), sural nerve (SuN), and medial plantar nerve (MpN) stimulation during two tasks in which opposite reactions are functionally expected: normal walking (NW), just before ipsilateral heel strike, and hybrid walking (HW) (legs walking in opposite directions), at ipsilateral push off and contralateral touchdown. Early crossed facilitations were observed in the contralateral GL after TN stimulation during NW, and a reversal of such responses occurred during HW. These results underline the functional significance of short-latency crossed responses and represent the first evidence for short-latency reflex reversal in the contralateral limb for humans. Muscle afferents seem to mediate the response during NW, while during HW cutaneous afferents are likely involved. It is thus possible that different afferents mediate the crossed response during different tasks.
Topics: Adult; Afferent Pathways; Female; Humans; Leg; Male; Muscle, Skeletal; Reaction Time; Reflex; Skin; Sural Nerve; Tibial Nerve; Walking
PubMed: 23427302
DOI: 10.1152/jn.01086.2012 -
Journal of Neurology, Neurosurgery, and... Dec 1985Two patients with congenital hypomyelinating neuropathy are reported with details of sural nerve pathology. The resemblance of this condition to the hypomyelinating...
Two patients with congenital hypomyelinating neuropathy are reported with details of sural nerve pathology. The resemblance of this condition to the hypomyelinating neuropathy of Trembler mice is discussed and the pertinent medical literature reviewed.
Topics: Axons; Biopsy; Child, Preschool; Diagnosis, Differential; Electromyography; Humans; Joint Instability; Male; Microscopy, Electron; Muscle Hypotonia; Muscles; Muscular Atrophy; Myelin Sheath; Polyneuropathies; Sural Nerve
PubMed: 4087003
DOI: 10.1136/jnnp.48.12.1269