Sural Nerve Research Articles

Selective neural inhibition via photobiomodulation alleviates behavioral hypersensitivity associated with small sensory fiber activation.

Photobiomodulation at higher irradiances has great potential as a pain-alleviating method that selectively inhibits small diameter nerve fibers and corresponding sensory experiences, such as nociception and heat sensation. The longevity and magnitude of these effects as a function of laser irradiation parameters at the nerve was explored. In a rodent chronic pain model (spared nerve injury-SNI), light was applied directly at the sural nerve with four delivery schemes: two irradiance levels (7.64 and 2.55 W/cm2 ) for two durations each, corresponding to either 4.8 or 14.4 J total energy, and the effect on sensory hypersensitivities was evaluated. At emitter irradiances of 7.64 W/cm2 (for 240 s), 2.55 W/cm2 (for 720 s), and 7.64 W/cm2 (for 80 s) the heat hypersensitivity was relieved the day following photobiomodulation (PBM) treatment by 37 ± 8.1% (statistically significant, p < 0.001), 26% ± 6% (p = 0.072), and 28 ± 6.1% (statistically significant, p = 0.032), respectively, and all three treatments reduced the hypersensitivity over the course of the experiment (13 days) at a statistically significant level (mixed-design analysis of variance, p < 0.05). The increases in tissue temperature (5.3 ± 1.0 and 1.3 ± 0.4°C from 33.3°C for the higher and lower power densities, respectively) at the neural target were well below those typically associated with permanent action potential disruption. The data from this study support the use of direct PBM on nerves of interest to reduce sensitivities associated with small-diameter fiber activity.

Central nervous system involvement in chronic inflammatory demyelinating polyradiculoneuropathy—MRS and DTI study

ObjectiveThe current research aimed to analyze the alterations within the motor cortex and pyramidal pathways and their association with the degree of damage within the peripheral nerve fibers in patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). To achieve that goal, we investigated the microstructural changes within the pyramidal white matter tracts using diffusion tensor imaging (DTI) parameters, evaluated metabolic alterations in both precentral gyri using magnetic resonance spectroscopy (MRS) ratios, and correlated them with the neurographic findings in patients with CIDP.MethodsThe spectroscopic ratios of NAA/Cr, Cho/Cr, and mI/Cr from both precentral gyri and the values of fractional anisotropy (FA), axial diffusivity (AD), and mean diffusivity (MD) from both of the corticospinal tracts were correlated with the results of neurological and neurographic findings. The comparison of DTI parameters between the patients and controls was performed using Student’s t-test or the Mann–Whitney U test. Due to the lack of normal distribution of most variables, Spearman’s Rho rank coefficient was used to test all correlations. All analyses were performed at a significant level of alpha = 0.05 using STATISTICA 13.3.ResultsCompared to the control group (CG), the patient group showed significantly lower ratios of NAA/Cr (1.66 ± 0.11 vs. 1.61 ± 0.15; p = 0.022), higher ratios of ml/Cr in the right precentral gyrus (0.57 ± 0.15 vs. 0.61 ± 0.08; p = 0.005), and higher levels of Cho/Cr within the left precentral gyrus (0.83 ± 0.09 vs. 0.88 ± 0.14, p = 0.012). The DTI parameters of MD from the right CST and AD from the right and left CSTs showed a strong positive correlation (0.52–0.53) with the sural sensory nerve action potential (SNAP) latency of the right sural nerve. There were no other significant correlations between other DTI and MRS parameters and neurographic results.SignificanceIn our study, significant metabolic alterations were found in the precentral gyri in patients with CIDP without clinical symptoms of central nervous system involvement. The revealed changes reflected neuronal loss or dysfunction, myelin degradation, and increased gliosis. Our results suggest coexisting CNS damage in these patients and may provide a new insight into the still unknown pathomechanism of CIDP.

A Rare Atypical Case of Asymptomatic and Spontaneous Intraneural Hematoma of Sural Nerve: A Case Report and Literature Review.

Intraneural hematoma is a rare disease that results in an impaired nerve function because of bleeding around the peripheral nerve, with only 20 cases reported. Trauma, neoplasm, and bleeding disorders are known factors for intraneural hematoma. However, here we report atypical features of asymptomatic and spontaneous intraneural hematoma which are difficult to diagnose. A 60-year-old woman visited our clinic with the complaint of a palpable mass on the right calf. She reported no medical history or trauma to the right calf and laboratory findings showed normal coagulopathy. Ultrasonography was performed, which indicated hematoma near saphenous vein and sural nerve or neurogenic tumor. We performed surgical exploration and intraneural hematoma was confirmed on sural nerve. Meticulous paraneuriotomy and evacuation was performed without nerve injury. Histological examination revealed intraneural hematoma with a vascular wall. No neurologic symptoms were observed. In literature review, we acknowledge that understanding anatomy of nerve, using ultrasonography as a diagnostic tool and surgical decompression is key for intraneural hematoma. Our case report may help establish the implications of diagnosis and treatment. Also, we suggested surgical treatment is necessary even in cases that do not present symptoms because neurological symptoms and associated symptoms may occur later.

Entrapment of median nerve after elbow fracture dislocations: expected surgical time frame based on cadaver study.

Median nerve injuries occur in approximately 3% of pediatric elbow fracture dislocations. These rare injuries can be difficult to diagnose, and the results are poor in delay cases. Surgical timing is one of the most important prognostic factors. We aimed to present three patients with median nerve palsy who were referred to our clinic late, and according to these cases, we emphasized the expected time frame for exploration based on our anatomical cadaver study. Between 2008 and 2010, three patients were referred to our clinic because of median nerve paralysis after a treated elbow dislocation. The mean interval between injury and referral was 15 (min: 13-max: 18) months, and the mean age of the patients was 15 (13-18) years. Neurolysis was performed in two patients, and for the third patent, after neurolysis, axonal continuity was observed to be disrupted so sural nerve grafting was performed with four cables. Tendon transfers were performed in all patients. A total number of 20 upper extremities of 10 cadavers were dissected. Due to its proximal innervation and ease of assessment, the muscle innervation of the flexor pollicis longus (FPL) was planned to be evaluated. The distance from the medial epicondyle is calculated in the cadaver study where the nerve injury is found. The mean length from the medial epicondyle to the motor innervation of FPL was calculated in each specimen and found to be 101.99 millimeters (mm) (range: 87.5-134.2). The mean longest innervation of FPL was 110.83 mm from (range 87.5-148.1) the medial epicondyle calculated by including each specimens longest nerve length. Knowing that the healing time of a nerve lesion is 1 mm per day, we calculated that the recovery of FPL would take approximately 4 months. When nerve healing is expected to be 1 mm a day in axonotmesis type injury, after the median nerve palsy following elbow dislocation, thumb flexion should be achieved in the following 4 months generally if the nerve was not entrapped in the joint. This cadaver-based study objectively defined how long to wait for the innervation of the FPL in median nerve injuries in elbow fracture dislocations.

Exuberant circumferential fibroproliferative neuromas in lipomatosis of nerve: a unifying theory. Illustrative case.

Lipomatosis of nerve (LN) is a rare disorder characterized by the massive enlargement of peripheral nerves, frequently accompanied by generalized fibroadipose proliferation and skeletal overgrowth. The authors have been routinely following a 20-year-old male for lipomatosis of median nerve at the wrist noted shortly after birth. He had undergone resection of the lesion accompanied by sural nerve grafting at another institution. Clinically, although his neurological loss of function has been stable, he has had continued soft tissue growth. Serial magnetic resonance imaging has revealed persistent LN proximal to the repair sites with evidence of fatty proliferation in the sural grafts and continued LN and fatty proliferation distally. There has been a progressive circumferential pattern of fibrosis around the proximal and distal suture lines, which has a similar radiological pattern to desmoid type fibromatosis (a pattern recently described in neuromuscular choristoma [NMC] desmoid-type fibromatosis). Considering the similar reaction of nerve in both LN and NMC despite differing genetic cascades, the authors believe a unifying process occurs in both lesions. The pattern of circumferential fibroproliferation would be most consistent with neuron-mediated growth from unspecified trophic factors, supporting a previously reported a nerve-derived "inside-out mechanism." The clinical consequences of this unifying process are presented.

Segmental motor neuron dysfunction in amyotrophic lateral sclerosis: Insights from H reflex paradigms.

In amyotrophic lateral sclerosis (ALS), the role of spinal interneurons in ALS is underrecognized. We aimed to investigate pre- and post-synaptic modulation of spinal motor neuron excitability by studying the H reflex, to understand spinal interneuron function in ALS. We evaluated the soleus H reflex, and three different modulation paradigms, to study segmental spinal inhibitory mechanisms. Homonymous recurrent inhibition (H'RI ) was assessed using the paired H reflex technique. Presynaptic inhibition of Ia afferents (H'Pre ) was evaluated using D1 inhibition after stimulation of the common peroneal nerve. We also studied inhibition of the H reflex after cutaneous stimulation of the sural nerve (H'Pos ). Fifteen ALS patients (median age 57.0 years), with minimal signs of lower motor neuron involvement and good functional status, and a control group of 10 healthy people (median age 57.0 years) were studied. ALS patients showed reduced inhibition, compared to controls, in all paradigms (H'RI 0.35 vs. 0.11, p = .036; H'Pre 1.0 vs. 5.0, p = .001; H'Pos 0.0 vs. 2.5, p = .031). The clinical UMN score was a significant predictor of the amount of recurrent and presynaptic inhibition. Spinal inhibitory mechanisms are impaired in ALS. We argue that hyperreflexia could be associated with dysfunction of spinal inhibitory interneurons. In this case, an interneuronopathy could be deemed a major feature of ALS.

Diagnostic contribution of multi-frequency vibrometry to detection of peripheral neuropathy in type 1 diabetes mellitus compared with nerve conduction studies.

The aim was to assess the use of multi-frequency vibrometry (MFV) in detecting diabetic peripheral neuropathy (DPN) in type 1 diabetes in comparison to nerve conduction studies (NCS) and neurothesiometer (NT). Our objectives were to examine how VPTs correlated with NCS parameters, evaluate the efficacy of MFV in distinguishing DPN as well as to investigate whether MFV procedure could be based on fewer frequencies. Adults with type 1 diabetes with previous MFV examinations were recruited at Skåne University Hospital in Malmö, Sweden, between 2018 and 2020. Participants were examined regarding nerve function in the lower limbs through MFV, NT and NCS. A total of 66 participants (28 women and 38 men) with a median age of 50 (39 to 64) years were included in the study. Through NCS assessment, 33 participants (50%) were diagnosed with DPN. We found negative correlations between VPTs and all NCS parameters, where the strongest correlation was found between sural nerve amplitude and the 125 Hz frequency of MFV. A combination of four frequencies, two low (4 and 8 Hz) and two high (125 and 250 Hz), showed the highest classification efficacy (AUC 0.83, 95% CI 0.73-0.93). We conclude that a strong correlation exists between the sural nerve amplitude and the VPTs at 125 Hz and that VPT testing with MFV can be focused on only four frequencies instead of seven, thus shortening test time, to distinguish DPN in the lower limb.

Early detection of peripheral neuropathy in patients with diabetes mellitus type 2

BackgroundEarly diagnosis of diabetic polyneuropathy (DPN) can significantly improve the prognosis and help prevent severe complications. The aim of this work was to study clinical, radiological, laboratory and neurophysiological findings for early detection of peripheral neuropathy in T2DM.MethodsA total of 60 diabetic patients were classified according to Toronto Clinical Neuropathy Score (TCNS) into: Group 1: 20 diabetic patients with no evident neuropathy. Group 2: 20 diabetic patients with mild neuropathy. Group 3: 20 diabetic patients with moderate and severe neuropathy. All patients underwent a neurological examination, nerve conduction studies and optical coherence tomography (OCT) to assess retinal nerve fiber layer (RNFL) thickness. Additionally, ELISA technique to measure serum interleukin-6 (IL-6).ResultsThe analysis of gender and age distributions among the groups revealed no significant differences. There were statistically significant differences regarding disease duration, HBA1c, body mass index Systolic and diastolic blood pressure. Group 3 had such significant impairment that resulted in an inability to record the measurements of sural nerves. The study's statistical analysis results for OCT variables, and post hoc comparisons revealed significant differences between all three groups. The results demonstrated significant variations in Serum IL6 levels among the groups, with Group 3 having the highest IL6 levels. In groups 1, 2, and 3 the area under the curve for IL-6 and RNFL showed a good differentiation ability between groups.ConclusionWe conclude that the total thickness RNFL and serum IL-6 levels are a potential biomarker in prediction the severity of DPN.

Glucagon-like peptide-1 receptor agonists reverse nerve morphological abnormalities in diabetic peripheral neuropathy.

Diabetic peripheral neuropathy (DPN) is a highly prevalent cause of physical disability. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are used to treat type 2 diabetes and animal studies have shown that glucagon-like peptide-1 (GLP-1) receptors are present in the central and peripheral nervous systems. This study investigated whether GLP-1 RAs can improve nerve structure. Nerve structure was assessed using peripheral nerve ultrasonography and measurement of tibial nerve cross-sectional area, in conjunction with validated neuropathy symptom scores and nerve conduction studies. A total of 22 consecutively recruited participants with type 2 diabetes were assessed before and 1 month after commencing GLP-1 RA therapy (semaglutide or dulaglutide). There was a pathological increase in nerve size before treatment in 81.8% of the cohort (n=22). At 1 month of follow-up, there was an improvement in nerve size in 86% of participants (p<0.05), with 32% returning to normal nerve morphology. A 3 month follow-up study (n=14) demonstrated further improvement in nerve size in 93% of participants, accompanied by reduced severity of neuropathy (p<0.05) and improved sural sensory nerve conduction amplitude (p<0.05). This study demonstrates the efficacy of GLP-1 RAs in improving neuropathy outcomes, evidenced by improvements in mainly structural and morphological measures and supported by electrophysiological and clinical endpoints. Future studies, incorporating quantitative sensory testing and measurement of intraepidermal nerve fibre density, are needed to investigate the benefits for small fibre function and structure.

The Medial Antebrachial Cutaneous Nerve Is a Low-Morbidity Alternative to the Standard Sural Nerve Autograft.

Nerve interposition grafting is an important technique in nerve reconstructive surgery that is used when a primary repair is not feasible without significant tension. This study sought to evaluate the long-term morbidity of the medial antebrachial cutaneous (MABC) nerve as an alternative donor nerve in comparison with sural nerve harvest. A single surgeon and institution retrospective chart review was performed to identify all patients who underwent nerve autografting using the sural and MABC as donor nerves between January 1, 2000 and December 31, 2019. Surveys assessed overall patient satisfaction with surgery, as well as donor and recipient site morbidity, satisfaction, pain, numbness, and cold sensitivity. Of the 73 patients contacted, 54 agreed to participate, and 43 of 73 (58.9%) ultimately completed the survey: 28 MABC (65.1%) and 15 sural (34.9%). There were no significant differences between the sural and MABC groups in overall satisfaction with surgery, donor and recipient site satisfaction, pain, cold sensitivity, and effect on quality of life. Even though 66.7% of sural donor sites and 75% of MABC donor sites had residual numbness, the effect this had on quality of life was very low (2 and 3, respectively). The MABC is a safe alternative to the traditional sural nerve autograft. A small subset of patients undergoing nerve autograft harvest will experience long-term morbidity in the form of pain. Conversely, the more common presence of numbness is not reported as bothersome.

Minimally Invasive Peroneal Tenodesis Assisted by Peroneal Tendoscopy: Technique and Preliminary Results.

Introduction: Peroneal disorders are a common cause of ankle pain and lateral instability and have been described in as much as 77% of patients with lateral ankle instability. Clicking, swelling, pain, and tenderness in the peroneal tendons track are frequent symptoms, but they can be confused with other causes of lateral ankle pain. The management of peroneal disorders can be conservative or surgical. When the conservative treatment fails, surgery is indicated, and open or tendoscopic synovectomy, tubularization, tenodesis or tendon transfers can be performed. The authors present a surgical technique of tendoscopy associated to minimally invasive tenodesis for the treatment of peroneal tendon tears, as well as the preliminary results of patients submitted to this procedure. Methods: Four patients with chronic lateral ankle pain who were diagnosed with peroneal brevis pathology were treated between 2020 and 2022 with tendoscopic-assisted minimally invasive synovectomy and tenodesis. Using a 2.7 mm 30° arthroscope and a 3.0 mm shaver blade, the entire length of the peroneus brevis tendon and most parts of the peroneus longus tendon can be assessed within Sammarco's zones 1 and 2. After the inspection and synovectomy, a minimally invasive tenodesis is performed. Results: All patients were evaluated at least six months after surgery. All of them reported improvement in daily activities and in the Foot Function Index (FFI) questionnaire (pre-surgery mean FFI = 23.86%; post-surgery mean FFI = 6.15%), with no soft tissue complications or sural nerve complaints. Conclusion: The tendoscopy of the peroneal tendons allows the surgeon to assess their integrity, confirm the extent of the lesion, perform synovectomy, prepare the tendon for tenodesis, and perform it in a safe and minimally invasive way, reducing the risks inherent to the open procedure.

Serum magnesium level and its correlation with sensory nerve conduction in type 2 diabetes mellitus patients

Background: Type 2 diabetes mellitus is a major public health problem. Chronic hyperglycemia in uncontrolled diabetes mellitus patients leads to microvascular and macrovascular complications. Diabetic peripheral neuropathy (DPN) has become the most common chronic diabetic complication, affecting about half of diabetic patients. DPN causes debilitating complications like foot ulcers and gangrene, leading to lower limb amputation and reducing the quality of life in diabetic patients. Serum magnesium has a close relationship with T2DM. It has been shown that lower serum magnesium levels are significantly associated with an increased risk of type 2 diabetes mellitus and with various complications of diabetes, including peripheral neuropathy, cardiovascular disease, nephropathy, retinopathy, and foot ulcers. Aim and Objective: The objective of the study is to compare serum magnesium levels and sensory nerve conduction in type 2 diabetes mellitus patients. Materials and Methods: This is a cross-sectional study that includes 75 participants in the age group of 35–45 years. The participants were divided into 2 groups. Group I: newly diagnosed type 2 DM patients, which included 25 female and 20 male patients. Group II: Type 2 DM patients who were taking treatment for more than 5 years, which included 15 female and 15 male patients. Under aseptic precautions, a blood sample was obtained, and the estimation of serum magnesium was determined by photocolorimetry. Sensory nerve conduction (median and sural nerve) was done using recorders and medicare systems EMG EP MARK II. Statistical analysis was done using IBM SPSS version 20.0 software. Pearson correlation analysis was used to check the correlation between sensory nerve conduction and serum magnesium. P &lt; 0.05 was taken as statistically significant. Results: In this study, the range of serum magnesium in group I was 1.5–2.9 mg/dl with a mean of 2.21 ± 0.3. The range of serum magnesium in group II was 1.4–2.5 mg/dl with a mean of 1.94 ± 0.3. The Pearson correlation between the parameters of sensory nerve conduction (median and sural nerve) and serum magnesium in terms of latency, amplitude, and conduction velocity in group I was -0.533, 0.471, 0.094, and -0.28, 0.029, 0.082, respectively; similarly, for group II, it was −0.27, 0.163, 0.607, and −0.071, 0.177, 0.028. The latency of all nerves was negatively correlated with serum magnesium. The amplitude and conduction velocities of all nerves were positively correlated with serum magnesium. Hence, serum magnesium seems to be a very good indicator of the effect of diabetes mellitus on peripheral nerves. Conclusion: In our study, we found out that serum magnesium seems to be a very good indicator of the effect of diabetes mellitus on peripheral nerves.

Sensory nerve conduction studies in infants, children and teenagers – An update

ObjectiveNerve conduction studies (NCS) in children remain technically challenging and depend on the cooperation of the child. Motor NCS are not compromised by analgosedation but data for sensory NCS are lacking. Here, we ask whether sensory NCS is influenced by analgosedation. We also compare the present data with NCS studies from the 1990s regarding anthropometric acceleration of the contemporary paediatric population. MethodsSensory NCS of the median nerve and sural nerve were performed in 182 healthy subjects aged 1 to 18 years during general anaesthesia and in 47 of them without analgosedation. ResultsSensory NCS was not influenced by midazolam or propofol. The sensory nerve action potential (SNAP) amplitude and the nerve conduction velocity (NCV) of the sural nerve as well as the SNAP of the median nerve show no significant age dependence in age range 1–18 years. The sensory NCV of the median nerve increased age-dependent. ConclusionsIn clinical practice, analgosedation can be used for diagnostic NCS. Sensory NCS data show no relevant secular trend over the last 30 years. Differences due to technical inconsistency predominate. SignificanceAnalgosedation can improve diagnostic quality of sensory NCS in children. Additionally, we provide sensory NCS values from a large pediatric cohort.

Minimally invasive subtalar joint and talonavicular joint preparation for hindfoot arthrodesis: A Cadaveric study evaluating structures at risk

Minimally invasive surgery (MIS) is growing in popularity due to smaller incisions, faster recovery times with less post-operative pain, and measurable decreases in morbidity. Our center performed an MIS hindfoot joint preparation about the talonavicular and subtalar joints and defined structures at risk in order to make this procedure more reproducible. Using ten fresh frozen cadaver limbs, we created a medial and lateral portal for talonavicular joint (TN) access, and an additional portal for subtalar joint (STJ) access to prepare the subtalar joint. After denuding the aforementioned joints of cartilage, the specimens were dissected to identify nearby anatomical structures. We documented the position of the peroneal sheath and sural nerve relative to the STJ portal, and the position of the dorsalis pedis artery (DP), medial dorsal cutaneous nerve (MDCN), extensor hallucis longus (EHL), extensor digitorum longus (EDL), tibialis anterior (TA), and tibialis posterior (TP) tendons relative to the TN portals. The average distance of the sural nerve and the peroneal sheath from the STJ portal was 34.21 mm and 14.12 mm respectively. The average distance of the DP, MDCN, and deep peroneal nerve from the medial and lateral TN portals were 13.31 mm, 11.54 mm, and 17.14 respectively. No neurovascular structures were transected throughout joint preparation. To our knowledge this is the first study looking into structures at risk for this specific procedure.

Evaluation of Brain Stem Function in Diabetics with and Without Distal Symmetrical Polyneuropathy Using the Blink Reflex

 Background: Diabetic peripheral neuropathy (DPN) is the commonest complication of T2DM. Neuropathy is a descriptor for a spectrum of clinical and subclinical symptoms with varying anatomical distributions, clinical histories, and perhaps underlying pathogenetic mechanisms. The distal Symmetrical sensory polyneuropathy is chronic, symmetrical, length-dependent sensorimotor. Studies of the blink reflex have shown potential as a method of assessing brainstem activity. Objective: The primary purpose of this research was to assess the function of the blink reflex in the early detection of cranial nerves and brain stem dysfunction in diabetes patients with and without polyneuropathy. We also aimed to see whether there were differences in blink reflex abnormalities between diabetes individuals with and without polyneuropathy. Patients and Methods: The study included a group of sixty-60 diabetic patients. Clinician and electrophysiologist evaluations were used to determine the severity of neuropathy. Patients with diabetes were separated into two groups: those with and without neuropathy. Results: A statistically significant difference between the two groups was for C.R.2 latency, and I.R.2 latency with a P-value &lt;0.001. Except for blink reflex’s R1 latency (P-value &gt;0.2), all other Blink reflex parameters were statistically different between patients who experience diabetic neuropathy and those who didn’t. Regarding HbA1c, a significant positive association with IR2 latency and C.R.2 latency was noted (Pvalue &lt;0.001) and also, a statistically significant negative association was found with I.R.2 duration and C.R.2 duration (P-value &lt;0.001). Amplitudes of sural, tibial and peroneal nerves were negatively associated with Blink reflex Latencies and positively associated with blink reflex duration. Conclusion: In conclusion, blink-reflex parameters (including ipsi-lateral R.2 latency, contra-lateral R.2 latency) are significantly associated with HBA1C level and degree of peripheral diabetic neuropathy. Received Sept. 2022 Accepted Nov. 2023 Published Jan. 2024

Harnessing historical data to derive reference limits – A comparison of e-norms to traditionally derived reference limits

ObjectiveNerve conduction studies (NCS) require valid reference limits for meaningful interpretation. We aimed to further develop the extrapolated norms (e-norms) method for obtaining NCS reference limits from historical laboratory datasets for children and adults, and to validate it against traditionally derived reference limits. MethodsWe compared reference limits obtained by applying a further developed e-norms with reference limits from healthy controls for the age strata’s 9–18, 20–44 and 45–60 years old. The control data consisted of 65 healthy children and 578 healthy adults, matched with 1294 and 5628 patients respectively. Five commonly investigated nerves were chosen: The tibial and peroneal motor nerves (amplitudes, conduction velocities, F-waves), and the sural, superficial peroneal and medial plantar sensory nerves (amplitudes, conduction velocities). The datasets were matched by hospital to ensure identical equipment and protocols. The e-norms method was adapted, and reference limit calculation using both ±2 SD (original method) and ±2.5 SD (to compensate for predicted underestimation of population SD by the e-norms method) was compared to control data using ±2 SD. Percentage agreement between e-norms and the traditional method was calculated. ResultsOn average, the e-norms method (mean ±2 SD) produced slightly stricter reference limits compared to the traditional method. Increasing the e-norms range to mean ±2.5 SD improved the results in children while slightly overcorrecting in the adult group. The average agreement between the two methods was 95 % (±2 SD) and 96 % (±2.5 SD). ConclusionsThe e-norms method yielded slightly stricter reference limits overall than ones obtained through traditional methods; However, much of the difference can be attributed to a few outlying plots where the raters found it difficult to apply e-norms correctly.The two methods disagreed on classification of 4–5% of cases. Our e-norms software is suited to analyze large amounts of raw NCS data; it should further reduce bias and facilitate more accurate ratings. SignificanceWith small adaptations, the e-norms method adequately replicates traditionally derived reference limits, and is a viable method to produce reference limits from historical datasets.

Current treatment concepts for Achilles tendon rupture.

Achilles tendon rupture is a common and primary cause of lower limb tendon injury suffered during sports-related activities. The causes of Achilles tendon rupture include the calf muscle and tendon overuse, poor tendon quality, and various medical conditions. Historically, acute Achilles tendon rupture was treated conservatively. However, historical techniques are now associated with an increased risk of rerupture. To address this problem, open repair has been proposed. Open repair is associated with a reduced risk of rerupture; however, it is also closely associated with wound complications, like wound infection, whose treatment is time-consuming and costly. Therefore, minimally invasive Achilles tendon repair has been proposed as a promising option with acceptable functional outcomes. Nevertheless, despite its benefits, minimally invasive Achilles tendon repair is associated with increased risks of sural nerve injury and rerupture. In this review, we evaluate the currently used treatment strategies for acute Achilles tendon rupture and their historical evolution to provide evidence-based recommendations for physicians.

Sensory Chronic Inflammatory Demyelinating Polyradiculoneuropathy: Neglected Immunotherapy-Responsive Sensory Neuropathy.

To report an improvement with immunotherapy in 34 (85%)/40 patients who required an immunotherapy among 56 patients with sensory chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Sensory CIDP was diagnosed when two inclusion criteria are met: 1) acquired, chronic progressive or relapsing symmetrical or asymmetrical sensory polyneuropathy that had progressed for >2 months; and 2) definite electrophysiological and/or biopsy evidence of demyelinating neuropathy. Fifty-six patients with sensory CIDP were identified. Evidence of demyelination was obtained from by the routine motor nerve conduction study (NCS) in 39 (70%) patients, from a nerve biopsy in 10, and from a near-nerve needle sensory NCS in 7 patients. The most prominent laboratory abnormality was a high protein level in the cerebrospinal fluid in 21 (49%) of 43 tested patients. Immunotherapy was required in 41 (79%) of the 52 followed-up patients. An improvement with immunotherapy was observed in 36 (88%)/41 patients. In three patients, motor weakness developed in 5-8 years' follow-up period and so, their diagnosis was changed to CIDP. Sensory CIDP is responded to an immunotherapy in 88% of the treated patients. Sensory CIDP was diagnosed by the routine motor NCS in 70% of patients and by a sural nerve biopsy in 18% of patients. Thus, sensory CIDP should be recognized as a treatable CIDP variant among the different types of "idiopathic sensory neuropathy."

[Neuropathy in n-hexane poisoning].

N-Hexane is a solvent widely used in manufacturing as a cleaner, degreaser and component of rubber cement. Chronic exposure to n-hexane either through contact with unprotected skin or inhalation can lead to the development of clinical symptoms and electrophysiological changes similar to those of inflammatory demyelinating polyneuropathy which requires careful differential diagnosis. This article presents three cases of severe predominantly motor polyneuropathy with demyelinating features in 15- and 16-year-old adolescents. The results of laboratory tests were within normal limits; electroneuromyography revealed symmetrical involvement of sensory and motor fibers of the nerves of the legs and arms with a decrease in the speed of propagation of excitation and conduction blocks. Sural nerve biopsy revealed intraneural and perineural swelling without any signs of inflammation or fibrosis confirming the genesis of the neuropathy. Despite a relatively favorable prognosis there is no specific therapy for hexane poisoning and the recovery period can last up to several years.

Episodic Neurological Dysfunction in X-Linked Charcot-Marie-Tooth Disease: Expansion of the Phenotypic and Genetic Spectrum.

X-linked Charcot-Marie-Tooth disease type 1 (CMTX1) is characterized by peripheral neuropathy with or without episodic neurological dysfunction. We performed clinical, neuropathological, and genetic investigations of a series of patients with mutations of the gap-junction beta-1 gene (GJB1) to extend the phenotypic and genetic description of CMTX1. Detailed clinical evaluations, sural nerve biopsy, and genetic analysis were applied to patients with CMTX1. We collected 27 patients with CMTX1 with GJB1 mutations from 14 unrelated families. The age at onset (AAO) was 20.9±12.2 years (mean±standard deviation; range, 2-45 years). Walking difficulties, weakness in the legs, and pes cavus were common initial symptoms. Compared with female patients, males tended to have a younger AAO (males vs. females=15.4±9.6 vs. 32.0±8.8 years, p=0.002), a longer disease course (16.8±16.1 vs. 5.5±3.8 years, p=0.034), and more-severe electrophysiological results. Besides peripheral neuropathy, six of the patients had special episodic central nervous system (CNS) evidence from symptoms, signs, and/or reversible white-matter lesions. Neuropathology revealed the loss of large myelinated fibers, increased number of regenerated axon clusters with abnormally thin myelin sheaths, and excessively folded myelin. Genetic analysis identified 14 GJB1 variants, 6 of which were novel. These findings expand the phenotypic and genetic spectrum of CMTX1. Although CMTX1 was found to have high phenotypic and CNS involvement variabilities, detailed neurological examinations and nerve conduction studies will provide critical clues for accurate diagnoses. Further exploration of the underlying mechanisms of connexin 32 involvement in neuropathy or CNS dysfunction is warranted to develop promising therapies.