Left Sural Nerve Research Articles

Ischemic Sciatic Neuropathy in a Patient with Liposarcoma

Background Various etiologies are the causative agents for sciatic neuropathy. We present here a case of ischemic sciatic neuropathy in a patient with liposarcoma. Case report A 55-year-old woman presented with severe pain and weakness of the left leg. She had a history of recurred retroperitoneal liposarcoma, and was being administered chemotherapy. Examination revealed weakness in ankle dorsiflexion, plantar flexion and hamstring. Complaints also included dysesthesia, and numbness in the sole and dorsum of the foot. Nerve conduction study showed low compound muscle action potentials and slow motor conduction velocity of left peroneal and tibial nerves, with indiscernible sensory nerve action potentials of the left superficial peroneal and sural nerves. Computed tomography angiography revealed occlusion of the left common iliac artery. Commencement of intravenous infusion of heparin resulted in skin color change and progression of the weakness. Hence, the patient underwent an emergency thrombectomy. Conclusions Ischemia should be considered as a cause of sciatic neuropathy in cancer patients, which requires management with timely treatment. Key Words: Sciatic neuropathy; Liposarcoma; Ischemia

Nerve Conduction Study on Sural Nerve among Nepalese Tailors Using Mechanical Sewing Machine.

The use of new technologies and innovations are out of access for people living in a developing country like Nepal. The mechanical sewing machine is still in existence at a large scale and dominant all over the country. Tailoring is one of the major occupations adopted by skilled people with lower socioeconomic status and education level. Sural nerves of both right and left legs are exposed to strenuous and chronic stress exerted by chronic paddling of mechanical sewing machine with legs. To evaluate the influence of chronic and strenuous paddling on right and left sural nerves. The study recruited 30 healthy male tailors with median age {34(31-37.25)} years (study group), and, 30 healthy male volunteers with age {34(32-36.25)} years (control group). Anthropometric measurements (age, height, weight, BMI and length of both right and left legs) as well as cardio respiratory measurements [Systolic Blood Pressure (SBP), Dystolic Blood Pressure (DBP), Pules Rate (PR) and Respiratory Rate (RR)] were recorded for each subject. Standard nerve conduction techniques using constant measured distances were applied to evaluate sural nerve (sensory) in both legs of each individual. The differences in variables between the study and control groups were tested using Student's t-test for parametric variables and Mann-Whitney U test for nonparametric variables. A p-value of ≤ 0.05 was considered significant. Age, height, weight, body mass index and leg length were not significantly different between tailors and control groups. Cardio respiratory measurements (SBP, DBP, PR and RR) were also not significantly altered between both the groups. The sensory nerve conduction velocities (m/s) of the right {44.23(42.72-47.83) vs 50(46- 54)} and left sural nerves {45.97±5.86 vs 50.67±6.59} m/s were found significantly reduced in tailors in comparison to control group. Similarly amplitudes (μv) of right sural (20.75±5.42 vs 24.10±5.45) and left sural nerves {18.2(12.43-21.8) vs 32.0(26.5-35.25)} were significantly less in tailors in comparison to control group whereas, latencies (ms) of right sural {2.6(2.2-2.7) vs 2.0(2.0-2.250} and left sural nerve {2.4(2.07-2.72) vs 2.0(2.0-2.0)} were found significantly high in tailors as compared with control group. Operating mechanical sewing machine by paddling chronically and arduously could have attributed to abnormal nerve conduction study parameters due to vibration effect of the machine on right and left sural nerves. The results of present study follow the trend towards presymptomatic or asymptomatic neuropathy similar to subclinical neuropathy.

Peripheral nerve function in patients with excessive fragmentary myoclonus during sleep

ObjectivesExcessive fragmentary myoclonus is a frequent incidental finding in patients undergoing polysomnography for other reasons. The aim of this study was to evaluate whether electrophysiological examination in patients with excessive fragmentary myoclonus during sleep according to American Academy of Sleep Medicine (AASM) criteria shows findings of peripheral nerve dysfunction. MethodsNinety-eight of 100 patients with excessive fragmentary myoclonus detected as an incidental finding during routine polysomnography underwent electrophysiological workup. Motor nerve conduction studies of the right peroneal and tibial nerves, F-wave recordings of the tibial nerve, antidromic sensory nerve conduction studies of the left sural nerve and needle electromyography of the right tibialis anterior muscle were performed and classified as normal, peripheral neuropathy, lumbar 5 (L5) nerve root lesion, or benign fasciculations. ResultsFifty percent (49 out of 98) presented with electrophysiological abnormalities, most frequently polyneuropathy (32 out of 49, 65.3%), followed by L5 nerve root lesions (13 out of 49, 26.5%) and benign fasciculations (4 out of 49, 8.2%). Patients with electrophysiological abnormalities were older than those without. ConclusionsThe high prevalence of abnormal neurophysiological findings in patients with excessive fragmentary myoclonus during polysomnography suggests that excessive fragmentary myoclonus during sleep according to AASM criteria is not primarily a sleep-related phenomenon, but only persists during sleep and points to peripheral nerve pathology at least in part of the cases. Patients with incidental EFM during polysomnography should undergo electrophysiological workup for peripheral nerve pathology.

Clinical and electrophysiological studies of oxaliplatin-induced peripheral neuropathy

To identify the sensitive scales and the early change of nerve conduction for chronic oxaliplatin-induced peripheral neuropathy (OXLIPN), and to investigate correlation between the symptoms of acute OXLIPN and chronic OXLIPN. Between December 2014 and August 2015, 16 colorectal cancer patients confirmed by pathology, from department of Oncology, Chinese PLA General Hospital, scheduled to receive XELOX, completed the acute neurotoxic symptoms questionnaire at the end of 1 cycles and the scales of TNSc and NCI-CTC at the baseline and the end of 4 cycles. Nerve conduction studies (bilateral peroneal nerves and sural nerves) were performed in 11 patients at the baseline and the end of 4 cycles. After chemotherapy, TNSc increased 1-9 points for all cases, while NCI-CTC increased 1 point for only 9 cases, the remaining 7 cases had the same NCI-CTC score before and after chemotherapy, where TNSc increased 1-6 points. Left sural nerve a-SNAP (amplitude of sensory nerve action potential) was (15.3±5.8)μV before chemotherapy and(12.3±5.0)μV after chemotherapy. Right sural nerve a-SNAP was (17.4±8.6)μV before chemotherapy and (13.3±6.7)μV after chemotherapy. After chemotherapy, these datum were significantly reduced for left peroneal nerve distal and proximal a-CMAP (amplitude of compound muscle action potential), bilateral sural nerve a-SNAP and left sural nerve SCV (sensory conduction velocity) (P<0.05). After chemotherapy, TNSc was correlated significantly with the acute neurotoxic symptoms questionnaire (Spearman r=0.698, P=0.003). TNSc is more sensitive to the severity and changes in chronic OXLIPN than NCI-CTC. Sural nerve a-SNAP has a higher sensitivity for the early changes of nerve conduction studies in chronic OXLIPN. Patients who have more symptoms of acute OXLIPN are those who eventually develop more severe chronic OXLIPN.

Vitamin B-12 treatment of asymptomatic, deficient, elderly Chileans improves conductivity in myelinated peripheral nerves, but high serum folate impairs vitamin B-12 status response assessed by the combined indicator of vitamin B-12 status

It is uncertain whether vitamin B-12 supplementation can improve neurophysiologic function in asymptomatic elderly with low vitamin B-12 status or whether folate status affects responses to vitamin B-12 supplementation. We assessed the effects of a single intramuscular injection of 10 mg vitamin B-12 (which also contained 100 mg vitamin B-6 and 100 mg vitamin B-1) on vitamin B-12 status and neurophysiologic function in elderly community-dwelling Chileans with low serum vitamin B-12 concentrations who were consuming bread fortified with folic acid. A pretreatment and posttreatment study was conducted in 51 participants (median ± SD age: 73 ± 3 y; women: 47%) with serum vitamin B-12 concentrations <120 pmol/L at screening. Vitamin B-12 status was defined by combining vitamin B-12, plasma total homocysteine (tHcy), methylmalonic acid (MMA), and holotranscobalamin into one variable [combined indicator of vitamin B-12 status (cB-12)]. The response to treatment was assessed by measuring cB-12 and neurophysiologic variables at baseline and 4 mo after treatment. Treatment increased serum vitamin B-12, holotranscobalamin, and cB-12 (P < 0.001) and reduced plasma tHcy and serum MMA (P < 0.001). Treatment produced consistent improvements in conduction in myelinated peripheral nerves; the sensory latency of both the left and right sural nerves improved on the basis of faster median conduction times of 3.1 and 3.0 ms and 3.3 and 3.4 ms, respectively (P < 0.0001). A total of 10 sensory potentials were newly observed in sural nerves after treatment. Participants with high serum folate at baseline (above the median, ≥33.9 nmol/L) had less improvement in cB-12 (P < 0.001) than did individuals whose serum folate was less than the median concentration (i.e., with a concentration <33.9 nmol/L). Asymptomatic Chilean elderly with poor vitamin B-12 status displayed improved conductivity in myelinated peripheral nerves after vitamin B-12 treatment and an interaction with folate status, which was detected only with the use of cB-12. This trial was registered at www.controlled-trials.com as ISRCTN02694183.

Diffusion Tensor Imaging Tractography in Pure Neuritic Leprosy: First Experience Report and Review of the Literature.

Five years after both right ulnar and median nerve decompression for paraesthesias and palsy, a patient, coming from Nigeria but living in Italy, came to our unit claiming to have persistent pain and combined median and ulnar palsy. Under suspicion of leprosy, skin and left sural nerve biopsy were performed. Skin tests were negative, but Schwann cells resulted as positive for acid-fast bacilli (AFB), leading to the diagnosis of Pure Neuritic Leprosy (PNL). The patient was given PB multidrug therapy and recovered from pain in two months. After nine months both High Resolution Ultrasonography (HRUS) and Magnetic Resonance Imaging (MRI) were performed, revealing thickening of the nerves. Since demyelination is common in PNL, the Authors started to use Diffusion Tensor Imaging Tractography (DTIT) to get better morphological and functional data about myelination than does the traditional imaging. DTIT proved successful in showing myelin discontinuity, reorganization, and myelination, and the Authors suggest that it can give more information about the evolution of the disease, as well as further indications for surgery (nerve decompression, nerve transfers, and babysitting for distal effector protection), and should be added to traditional imaging tools in leprosy.

Sural Nerve Conduction Studies in Prediabetics and Diabetics in North Indian Population

Nerve conduction studies (NCS) are the most sensitive and reproducible measure of peripheral nerve functions. These can define and quantitate normal nerve activity. These tests examine the state of rapidly conducting myelinated fibres in a peripheral nerve. Most of the nerve dysfunctions begin in the sensory nerves of the lower extremities. So measurement of sensory function in the lower limb nerves by electrical stimulation is investigational in diabetics. The sensory nerve conduction velocity (SNCV) and sensory latency (SNSL) of sural nerve provides the highest diagnostic sensitivity. Evaluation of sural nerve conduction velocity in prediabetic and diabetic to assess neuropathy. Examination of nerve conduction velocity (NCV) was done in 79 subjects (16 prediabetic and 63 diabetics) by using Synergy machine Viasys. Right and left sural nerve latency were significantly higher and sural nerve velocity were significantly lower in diabetics when compared to prediabetics but in both nerve amplitudes did not differed significantly. Increased Sural nerve latency indicates increased demyelination and decreased sural velocity shows decreased speed of nerve impulse in diabetics when compared to prediabetics indicating progressive neuropathy in diabetics.

Electrochemical skin conductance to detect sudomotor dysfunction, peripheral neuropathy and the risk of foot ulceration among Saudi patients with diabetes mellitus.

BackgroundSudomotor dysfunction is manifested clinically as abnormal sweating leading to dryness of feet skin and increased risk of foot ulceration. The aim of this study was to test the performance of foot electrochemical skin conductance (ESC) to detect diabetic peripheral neuropathy and the risk of foot ulceration against traditional methods in Saudi patients with diabetes mellitus.MethodsThis cross-sectional study was conducted on 296 Saudi patients with diabetes mellitus. Painful neuropathic symptoms were evaluated using the neuropathy symptom score (NSS). The risk of foot ulceration and diabetic peripheral neuropathy were determined using the neuropathy disability score (NDS). Vibration perception threshold (VPT) was assessed using neurothesiometer. Neurophysiological assessment of the right and left sural, peroneal and tibial nerves was performed in 222 participants. Diabetic peripheral neuropathy was defined according to the definition of the American Academy of Neurology. ESC was measured with Sudoscan.ResultsFeet-ESC decreased as the scores of sensory and motor function tests increased. Feet-ESC decreased as the NSS, NDS and severity of diabetic peripheral neuropathy increased. Sensitivity of feet-ESC < 50μS to detect diabetic peripheral neuropathy assessed by VPT ≥ 25 V, NDS ≥ 3, NDS ≥ 6 was 90.1, 61 and 63.8 % respectively and specificity 77, 85 and 81.9 % respectively. Sensitivity of feet-ESC < 70μS to detect diabetic peripheral neuropathy assessed by VPT ≥ 25 V, NDS ≥ 3, NDS ≥ 6 was 100, 80.6 and 80.9 % respectively. Sensitivity and specificity of feet-ESC < 70μS to detect confirmed-diabetic peripheral neuropathy were 67.5 and 58.9 % respectively.ConclusionSudoscan a simple and objective tool can be used to detect diabetic peripheral neuropathy and the risk of foot ulceration among patients with diabetes mellitus. Prospective studies to confirm our results are warranted.

Scientific Letter: Sodium valproate for the treatment of mania in a patient with Charcot-Marie-Tooth disease

?? Charcot-Marie-Tooth disease (CMT), also known as Hereditary Sensory Motor Neuropathy (HSMN) is the most common inherited peripheral neuropathy and it can follow autosomal dominant, Xlinked, autosomal recessive and even a sporadic inheritance pattern. 1Very few studies have evaluated psychiatric problems in this disease 2,3 , but there is a 30% lifetime prevalence of psychiatric disorder in patients with CMT. 2 Depression and phobic disorder are commonly occurring psychiatric comorbidities. 3After obtaining informed consent, we report the case of a patient with Charcot-Marie‐Tooth disease presenting with a manic episode and the treatment thereof with sodium valproate. Mr. L, a 28 year old male, presented with a two month history of talkativeness, irritable mood, increased physical activity and disturbed sleep. At the time of presentation, he was noted to be singing religious songs and had grandiose plans for the future. There was an increased physical activity throughout the day without associated fatigue. At times, he would even dance and he frequently cracked jokes with other patients. He had a history of several similar episodes in the past 10 years, almost one per year. In addition to this, he experienced generalized tonic-clonic seizures as a consequence of a head injury he sustained at the age of 14 years. He received antiepileptic medications (initially Phenytoin sodium and later Divalproex sodium) and remained seizure free for 8 years. There is also a history of progressive weakness and atrophy of his limbs, which had initially started in the distal, followed by the proximal aspects of both lower limbs, and later progressed to affect the upper limbs. As a result, he had difficulty in climbing stairs and getting up from a seated position. The patient’s younger sister, who had a similar history of weakness, atrophy and deformity of her limbs, had suffered from several depressive episodes over a period of 8 years. Investigations of patient i.e. haematology and biochemical tests were found to be normal. Magnetic resonance imaging of the patient’s brain as well as visual evoked potential and brainstem auditory evoked response were normal. The nerve conduction studies showed decreased conduction velocity of < 20m/s; with prolonged distal latencies, decreased compound muscle action amplitude and non-recordable sensory nerve axonal potential. Biopsy of the left sural nerve revealed “onion bulb” formation, fibrocystic proliferation, and increased endoneurial connective tissue. After psychiatric evaluation, he was diagnosed as a case of bipolar affective disorder, current episode mania with psychotic symptoms. The diagnosis of Charcot-Marie-Tooth disease was also entertained after consultation with a team of neurologists and psychiatrists. The patient was commenced on sodium valproate 1000mg per day for treatment of mania. Initially, risperidone 4mg was added to control aggression. Over a period of four weeks, his manic symptoms improved significantly and he achieved

Morphological and morphometric parameters of sural nerves of Wistar rats are not gender during development.

It is known that gender influences the re‐myelination, pain sensibilization, neural regulation of the vascular function, in vitro axonal growth and the conduction velocity of nerves. However, little is known about the influence of gender on peripheral nerves development. Previous studies from our laboratory described the development of the sural nerves in female rats [1] and concluded that at 180‐days of life the sural nerves are fully developed. We compared the morphological and morphometric aspects of different segments of the sural nerves in male (N=6) and female (N=6) adult (180 days of life) Wistar rats. The animals were anesthetized, perfused and the right and left sural nerves were removed and prepared for epoxy resin embedding and light microscopy. Morphometric analysis was performed with the aid of computer software, and took into consideration the fascicle area and diameter, as well as myelinated fiber number, density, area and diameter. Comparisons between segments and sides were performed and significant differences were considered when p&lt;0.05. The results showed that adult males are larger and heavier than the females. Nevertheless, there were no significant differences between genders, when the sural nerve fascicular parameters were compared. Thus, the morphological and morphometric parameters of sural nerve are not gender related.

Description of the microscopic anatomy of sural nerves in newborn rats.

The morphology of the sural nerve is widely study, however, little is known about the morphometry of this nerve in newborns. We describe the morphological and morphometric aspects of different segments of the sural nerve in female Wistar rats (N=6) with 15 days of life. The animals were anesthetized, perfused and the right and left sural nerves were removed and prepared for epoxy resin embedding and light microscopy. Morphometric analysis was performed with the aid of computer software, and took into consideration the fascicle area and diameter, as well as myelinated fiber number, density, area and diameter. Comparisons between segments and sides were performed and significant differences were considered when p&lt;0.05. There were no differences on the morphology and morphometry between the segments and sides of sural nerve in female Wistar rats with 15 days of life. Comparing the present results with previous data from our laboratory [1], we conclude that the newborns have similar fascicular parameters to those of 30 days‐old animals leading to the conclusion that the sural nerve is fully developed at birth and will grow following the animals’ body weight increase with age.

Sensory innervation of the rat hind paw: morphometric comparison between sural and saphenous nerves.

Previous studies on dermatome mappings of the rat hind paws investigated the C‐fibers distribution and then assumed that the A‐fibers distributions resemble that of the C‐fibers. We investigated the morphometry of fascicles and myelinated fibers (A‐fibers) in the sural and saphenous nerves in young rats. Six 30‐day‐old female Wistar rats had their right and left sural and saphenous nerves prepared for light microscopy and morphometry. Comparisons were made between segments (proximal vs distal) and sides (left vs right) for the same nerves and between nerves (sural vs saphenous) from the same side and differences were considered if p&lt;0.05. Both the sural and saphenous nerves are longitudinally symmetrical on both sides. Both nerves also exhibited lateral symmetry. Also, no significant differences were found between nerves. Myelinated fibers and respective axons diameter, as the G ratio histograms are unimodal in both nerves, regardless of segments or sides. This indicates that the nerves investigated did not reach fully development in animals aged 30 days. The similar number of myelinated fibers, associated with their similar size in both sural and saphenous nerves suggests that the innervation territory for both nerves is equally distributed at the foot. This information is useful for studies of sensory neuropathies, in particular, studies of nerve regeneration.

Hereditary Neuropathy with Liability to Pressure Palsy: A Recurrent and Bilateral Foot Drop Case Report

Hereditary neuropathy with liability to pressure palsy is characterized by acute, painless, recurrent mononeuropathies secondary to minor trauma or compression. A 16-year-old boy had the first episode of right foot drop after minor motorcycle accident. Electromyography revealed conduction block and slowing velocity conduction of the right deep peroneal nerve at the fibular head. After motor rehabilitation, he fully recovered. Six months later he had the second episode of foot drop in the opposite site after prolonged squatting position. Electromyography revealed sensorimotor polyneuropathy of left peroneal, sural, posterior tibial, and deep peroneal nerves and also of ulnar, radial, and median nerves of both upper limbs. Histological examination revealed sensory nerve demyelination and focal thickenings of myelin fibers. The diagnosis of hereditary neuropathy with liability to pressure palsy was confirmed by PMP22 deletion of chromosome 17p11.2. He started motor rehabilitation and avoidance of stressing factors with progressive recovery. After one-year followup, he was completely asymptomatic. Recurrent bilateral foot drop history, “sausage-like” swellings of myelin in histological examination, and the results of electromyography led the authors to consider the diagnosis despite negative family history. The authors highlight this rare disease in pediatric population and the importance of high index of clinical suspicion for its diagnosis.

変形性脊椎症を有する高齢者に発症したnonsystemic vasculitic neuropathyの1例

We report an 84-year-old woman with left lower limb muscle weakness and numbness who also had weakness in her right lower limb, which showed spontaneous partial improvement. Neurological examination revealed lower extremity weakness and sensory disturbance in all modalities, predominantly distally on the left side. Laboratory studies yielded normal results, except for a slightly high erythrocyte sedimentation rate. Nerve conduction studies showed axonal neuropathy in the right tibial nerve, and loss of action potentials in other lower limb nerves. Histological study of the left sural nerve revealed mainly loss of axons and differences in the density of fascicules in the axons. In addition, inflammatory cells infiltrated around small blood vessels. Therefore, we diagnosed nonsystemic vasculitic neuropathy. Magnetic resonance imaging revealed that she also had spondylosis deformans and radiculopathy, which was more difficult to differentiate. Neural biopsy was important for diagnosis.

Pain Perception in Schizophrenia: Evidence of a Specific Pain Response Profile

Ever since the characterization of schizophrenia, clinicians have noted abnormal pain sensitivity in their patients. The published literature, however, is inconsistent concerning the nature of the change reported. The objective of this study was to characterize the pain response profile of schizophrenic patients by providing both acute and prolonged (i.e., rapidly repeating) painful stimuli to schizophrenic participants and control subjects. Twelve schizophrenic subjects and eleven controls were included in the final analysis. Diagnosis was made according to Diagnostic and Statistical Manual of mental disorders-4th edition, text revision (DSM-IV-TR) criteria. Intermittent, transcutaneous stimulations of the left sural nerve were administered to all participants. Painful sural nerve stimulations provoked a nociceptive flexion reflex response which was measured using an electromyographic recording of the bicep femoris muscle. Pain ratings were obtained using a 0-10 verbal numerical scale. Among schizophrenic participants, the relationship between subjective pain, reflex amplitude, and clinical features was investigated. The Positive and Negative Syndrome Scale, Calgary Depression Scale for Schizophrenia, and Subjective Scale to Investigate Cognition in Schizophrenia were used to evaluate clinical features. Compared with controls, schizophrenic subjects showed increased sensitivity to acute pain (i.e., lower pain thresholds; P = 0.019), but decreased subjective pain sensitization (P = 0.027). Group differences in subjective pain sensitization were not accompanied by group differences in nociceptive reflex activity (P = 0.260), suggesting supraspinal origins to the change in pain experienced by schizophrenic subjects. Moreover, positive symptoms correlated negatively with pain threshold values among schizophrenic participants (r = -0.696, P = 0.012), suggesting that distortions of thought and function relate to pain sensitivity in schizophrenic patients. Results indicate that schizophrenic subjects present a specific experimental pain response profile, characterized by elevated sensitivity to acute pain but reduced sensitivity to prolonged pain.

Cyanocobalamin treatment improves vitamin B12 status and peripheral neuroconduction in deficient Chilean elderly

Few data are available on the effects of cyanocobalamin treatment on B12 status and neurological function in deficient but asymptomatic free‐living populations. The objective was to evaluate the effects of a single i.m. dose of 10,000 μg B12 on biomarkers and neurophysiology in Chilean elderly with B12 deficiency. The 34 subjects (70–79 y) were 52% female with serum B12 &lt;148 pmol/L had been excluded for ethical reasons from a larger RCT of B12 supplementation. B12 intake was 2.4±1.0 μg/d (67% met the EAR). Change in serum B12, total homocysteine (tHcy), methylmalonic acid (MMA), holo‐transcobalamin (holo‐TC), and sensory peripheral neuroconduction were assessed 4 mo after treatment. Serum B12 increased (p&lt;0.001) from 80 (44–121) to 231 (103–294) pmol/L after treatment and 78% exceed 148 pmol/L. Holo‐TC increased (p&lt;0.001) from 35 (27–41) to 56 (40–85) pmol/L and MMA reduced (p&lt;0.001) from 389 (263–654) to 220 (146–295) nmol/L. There were no significant changes in tHcy. At baseline, distal sensory latency of the right and left sural nerve was 3.4±0.3 msec and 3.3±0.3, respectively. The mean distal sensory latencies decreased (p&lt;0.0001) to 3.0±0.3 msec on both sides. 9 subjects clasified as demyelinating neuropathy normalized their distal latency post‐treatment. B12 biomarkers and latencies of the sural nerves detected adverse effects of B12 deficiency on neural function and reversibility after treatment. Funded by FONDECYT #10700592

Morphometry of nerves responsible for sensory innervation of the hind limbs in rats

The sensory innervation of the distal hind limb is achieved by branches of the sacral and lumbar plexuses. In rats, the skin of the dorsum of the foot is innervated mainly by the sural and saphenous nerves, with considerable overlapping between them. We aimed to compare the morphology and morphometry of the sural and saphenous nerves in young rats. Female Wistar rats (N=5) aged 30 days were perfused with 2.5% glutaraldehyde and had their right and left sural and saphenous nerves prepared for light microscopy and morphometry. Comparisons were made between segments (proximal and distal) and sides in the same nerves and between nerves of the same side. Both nerves are longitudinally symmetric on both sides. A lateral symmetry is also present on both nerves. In general, no differences were found between nerves, either for the fascicle or for the myelinated fibers morphometry. The similar number of myelinated fibers, associated with their similar size in both sural and saphenous nerves suggests that the innervation territory for both nerves is equally distributed. This information is useful for studies of sensory neuropathies, in particular, studies of pain.Grant Funding Source : FAPESP, CNPq, CAPES and FAEPA

Radiofrequency of the sural nerve: three case reports for treating chronic neuropathic pain with radiofrequency of the sural nerve in the veteran and civilian population

Radiofrequency has been a controversial interventional approach for chronic peripheral neuropathic pain. We report three cases in which this technique was employed, resulting in more successful pain relief than with other treatments (including pharmacotherapy, physical therapy, and other interventions). The first case is a 28 year-old male Veteran with a history of PTSD and chronic bilateral ankle pain, s/p multiple surgeries, with EMG evidence of severe axonal neuropathy of the left sural nerve.

Two nerve morphometry methods performed through the same computer program: are they comparable?

Morphometry has been widely used in studies designed to establish normal patterns of biological structures or to compare changes resulting from pathological processes. It can be performed manually or through semi‐automatic or automatic methods. However, it is difficult to compare results between studies that used different methods. We aimed to compare the results of two different methods of nerve morphometry, automatic and semi‐automatic, using the same computer software. Female Wistar rats (n = 5) with 90 days of age had their right and left sural nerves prepared for light microscopy. Automatic and semi‐automatic morphometry was performed using the program KS‐400 and took into consideration: area and lesser diameter of myelinated fibers and their axons, the myelin sheath area and the ratio between the lesser diameter of the axon and its respective myelinated fiber (G‐ratio). The nerves are longitudinally and laterally symmetric with both morphometric methods. A significant overestimation of the myelinated fibers size and a significant underestimation of the myelinated axons size were observed with the automatic method. Our results indicate an important differences in the values of the myelinated fibers morphometry of one nerve, obtained with two different methodologies. Thus, the same methodology must be standardized and used throughout a single experiment.Grant Funding Source : FAPESP, CNPq and FAEPA

Hemiplegic peripheral neuropathy accompanied with multiple cranial nerve palsy.

A 32-year-old man experienced double vision around January, 2010, followed by weakness of his left upper and lower extremities. Articulation disorders and loss of hearing in his left ear developed, and he was admitted to our hospital on February 14, 2010. Physical examination was normal, and neurological examination showed clear consciousness with no impairment of cognitive function, but with articulation disorders. Olfactory sensation was reduced. Left ptosis and left gaze palsy, complete left facial palsy, perceptive deafness of the left ear, and muscle weakness of the left trapezius muscle were observed. Paresis in the left upper and lower extremities was graded 4/5 through manual muscle testing. Sensory system evaluation revealed complete left-side palsy, including the face. Deep tendon reflexes were slightly diminished equally on both sides; no pathologic reflex was seen. No abnormality of the brain parenchyma, cerebral nerves or cervicothoracolumbar region was found on brain magnetic resonance imaging. On electroencephalogram, alpha waves in the main frequency band of 8 to 9 Hz were recorded, indicating normal findings. Brain single photon emission computed tomography (SPECT) scan showed reduced blood flow in the right inner frontal lobe and both occipital lobes. Nerve biopsy (left sural nerve) showed reduction of nerve density by 30%, with demyelination. The patient also showed manifestations of multiple cranial nerve disorder, i.e., of the trigeminal nerve, glossopharyngeal nerve, vagus nerve, and hypoglos-sal nerve. Whole-body examination was negative. Finally, based on ischemic brain SPECT images, spinal fluid findings and nerve biopsy results, peripheral neuropathy accompanied with multiple cranial nerve palsy was diagnosed.