Diagnostic efficiency of conventional ultrasound, shear wave elastography, and superb microvascular imaging in evaluating ulnar neuropathy at the elbow.

INTRODUCTION/AIMS: The current diagnosis of ulnar neuropathy at the elbow (UNE) relies mainly on the clinical presentation and nerve electrodiagnostic (EDX) testing, which can be uncomfortable and yield false negatives. The aim of this study was to investigate the diagnostic value of conventional ultrasound, shear wave elastography (SWE), and superb microvascular imaging (SMI) in diagnosing UNE. METHODS: We enrolled 40 patients (48 elbows) with UNE and 48 healthy volunteers (48 elbows). The patients were categorized as having mild, moderate or severe UNE based on the findings of EDX testing. The cross-sectional area (CSA) was measured using conventional ultrasound. Ulnar nerve (UN) shear wave velocity (SWV) and SMI were performed in a longitudinal plane. RESULTS: Based on the EDX findings, UNE severity was graded as mild in 4, moderate in 10, and severe in 34. The patient group showed increased ulnar nerve CSA and stiffness at the site of maximal enlargement (CSA mean at the site of max enlargement [CSAmax] and SWV mean at the site of max enlargement [SWVmax]), ulnar nerve CSA ratio, and stiffness ratio (elbow-to-upper arm), compared with the control group (p < .001). Furthermore, the severe UNE group showed higher ulnar nerve CSAmax and SWVmax compared with the mild and moderate UNE groups (p < .001). The cutoff values for diagnosis of UNE were 9.5 mm2 for CSAmax, 3.06 m/s for SWVmax, 2.00 for CSA ratio, 1.36 for stiffness ratio, and grade 1 for SMI. DISCUSSION: Our findings suggest that SWE and SMI are valuable diagnostic tools for the diagnosis and assessment of severity of UNE.

Double entrapment neuropathy of the ulnar nerve at the elbow and the wrist : double crush syndrome?

BACKGROUND: Double crush syndrome refers to a nerve in the proximal region being compressed, affecting its proximal segment. Instances of this syndrome involving ulnar and cubital canals during ulnar neuropathy are rare. Diagnosis solely through clinical examination is challenging. Although electromyography (EMG) and nerve conduction studies (NCS) can confirm neuropathy, they do not incorporate inching tests at the wrist, hindering diagnosis confirmation. We recently encountered eight cases of suspected double compression of ulnar nerve, reporting these cases along with a literature review. METHODS: The study included 5 males and 2 females, averaging 45.6 years old. Among them, 4 had trauma history, and preoperative McGowan stages varied. Ulnar neuropathy was confirmed in 7 cases at both cubital and ulnar canal locations. Surgery was performed for 4 cases, while conservative treatment continued for 3 cases. RESULTS: In 4 cases with wrist involvement, 2 showed ulnar nerve compression by a fibrous band, and 1 had nodular hyperplasia. Another case displayed ulnar nerve swelling with muscle covering. Among the 4 surgery cases, 2 improved from preoperative McGowan stage IIB to postoperative stage 0, with significant improvement in subjective satisfaction. The remaining 2 cases improved from stage IIB to IIA, respectively, with moderate improvement in subjective satisfaction. In the 3 cases receiving conservative treatment, satisfaction was significant in 1 case and moderate in 2 cases. Overall, there was improvement in hand function across all 7 cases. CONCLUSION: Typical outpatient examinations make it difficult to clearly differentiate the two sites, and EMG tests may not confirm diagnosis. Therefore, if a surgeon lacks suspicion of this condition, diagnosis becomes even more challenging. In cases with less than expected postoperative improvement in clinical symptoms of cubital tunnel syndrome, consideration of double crush syndrome is warranted. Additional tests and detailed EMG tests, including inching tests at the wrist, may be necessary. We aim to raise awareness double crush syndrome with ulnar nerve, reporting a total of 7 cases to support this concept.

Serial repetitive nerve stimulation studies in organophosphorus poisoning indicate two distinct pathophysiological processes occur at the neuromuscular junction in the intermediate syndrome.

INTRODUCTION: Intermediate syndrome is an important cause of respiratory failure following acute organophosphorus pesticide poisoning. The objective of this study was to examine the pathophysiology of this syndrome by analysis of sequential repetitive nerve stimulation studies in patients with acute organophosphorus pesticide poisoning. METHODS: Thirty-four consenting symptomatic patients with acute organophosphorus pesticide poisoning with intermediate syndrome (n = 10) or a milder forme fruste intermediate syndrome (n = 24) were assessed prospectively with daily physical examination and repetitive nerve stimulation done on the right and left median and ulnar nerves. The compound muscle action potential at 1, 3, 10, 15, 20 and 30 Hertz was measured with a train of ten stimuli. The amplitudes of the resulting stimuli were normalized to the first stimulus (100 per cent) and plotted against time. The decrease in the area under the curve of all the second stimulus compound muscle action potentials in the first 0.3 seconds was measured as a means of quantifying the refractory block. The decrease in the area under the curve under the 10, 15, 20 and 30 Hertz compound muscle action potentials relative to this pooled second stimulus compound muscle action potentials-area under the curve indicated the extent of additional rate-dependent block (decreasing compound muscle action potential-area under the curve over the first 0.3 seconds after the first stimulus with increasing Hertz). RESULTS: These new measurements strongly correlated with the severity of weakness. Refractory block was seen in most patients but was more severe in those with intermediate syndrome than those with forme fruste (partial) intermediate syndrome (median 55 per cent versus 16 per cent, P = 0.0001). Similar large differences were found for rate-dependent block (30 per cent versus 7 per cent, P = 0.001), which was uncommon in forme fruste intermediate syndrome but found in nine out of 10 patients with intermediate syndrome. Rate dependent block was generally only observed after 24 hours. The simplest strong predictor was total block at 30 Hertz repetitive nerve stimulation (89 per cent [interquartile range 73 to 94 per cent] versus 21 per cent [4 to 55 per cent]; P < 0.0001), which was very similar to total block calculated by summing other calculations. DISCUSSION: These findings likely represent depolarization and desensitization block from prolonged excessive cholinergic stimulation but it is not clear if these are from pre- or post-synaptic pathology. An animal model of intermediate syndrome with repetitive nerve stimulation studies might enable a better pathophysiological understanding of the two types of block. LIMITATIONS: The limited number of repetitive nerve stimulation studies performed were sufficient to demonstrate proof-of-concept, but further studies with more patients are needed to better define the correlates, clinical relevance and possible diagnostic/prognostic roles for the use of this technique. CONCLUSION: There are two easily distinguishable pathophysiological abnormalities in the neuromuscular block in intermediate syndrome. While they often coincide, both may be observed in isolation. The total and rate-dependent block at 30 Hertz are strongly associated with more severe weakness.

Ulnar neuropathy.

Ulnar neuropathy at the elbow is the second most common compressive neuropathy. Less common, although similarly disabling, are ulnar neuropathies above the elbow, at the forearm, and the wrist, which can present with different combinations of intrinsic hand muscle weakness and sensory loss. Electrodiagnostic studies are moderately sensitive in diagnosing ulnar neuropathy, although their ability to localize the site of nerve injury is often limited. Nerve imaging with ultrasound can provide greater localization of ulnar injury and identification of specific anatomical pathology causing nerve entrapment. Specifically, imaging can now reliably distinguish ulnar nerve entrapment under the humero-ulnar arcade (cubital tunnel) from nerve injury at the retro-epicondylar groove. Both these pathologies have historically been diagnosed as either "ulnar neuropathy at the elbow," which is non-specific, or "cubital tunnel syndrome," which is often erroneous. Natural history studies are few and limited, although many cases of mild-moderate ulnar neuropathy at the elbow appear to remit spontaneously. Conservative management, perineural steroid injections, and surgical release have all been studied in treating ulnar neuropathy at the elbow. Despite this, questions remain about the most appropriate management for many patients, which is reflected in the absence of management guidelines.

Evaluation of Hand-Arm Vibration Syndrome Owing to Nerve Conduction Study and Cumulative Exposure Index-A 2.5-Year Cohort Study.

OBJECTIVE: This study aims to clarify the relationship between peripheral neuropathy in hand-arm vibration syndrome and cumulative exposure index. METHODS: 68 participants without symptoms were surveyed. The participants were divided into three groups based on past and current vibration exposure (VE). RESULTS: Comparison among groups according to past VE showed that the median and ulnar sensory nerve conduction velocities and median sensory nerve action potential (SNAP) amplitude were significantly lower in past high and low exposure groups than in the past nonexposure group. Comparison among groups according to current VE showed that the median and ulnar SNAP amplitudes were significantly lower in the current high exposure group than in the current low or nonexposure group. CONCLUSIONS: Vibration tool handlers have potential peripheral nerve lesions at a certain stage without subjective symptoms of the finger.

Assessing ulnar neuropathy at the elbow using magnetoneurography.

OBJECTIVE: To measure neuromagnetic fields of ulnar neuropathy patients at the elbow after electrical stimulation and evaluate ulnar nerve function at the elbow with high spatial resolution. METHODS: A superconducting quantum interference device magnetometer system recorded neuromagnetic fields of the ulnar nerve at the elbow after electrical stimulation at the wrist in 16 limbs of 16 healthy volunteers and 21 limbs of 20 patients with ulnar neuropathy at the elbow. After artifact removal, neuromagnetic field signals were processed into current distributions, which were superimposed onto X-ray images for visualization. RESULTS: Based on the results in healthy volunteers, conduction velocity of 30 m/s or 50% attenuation in current amplitude was set as the reference value for conduction disturbance. Of the 21 patient limbs, 15 were measurable and lesion sites were detected, whereas 6 limbs were unmeasurable due to weak neuromagnetic field signals. Seven limbs were deemed normal by nerve conduction study, but 5 showed conduction disturbances on magnetoneurography. CONCLUSIONS: Measuring the magnetic field after nerve stimulation enabled visualization of neurophysiological activity in patients with ulnar neuropathy at the elbow and evaluation of conduction disturbances. SIGNIFICANCE: Magnetoneurography may be useful for assessing lesion sites in patients with ulnar neuropathy at the elbow.

Length of affected nerve segment in ulnar neuropathies at the elbow.

OBJECTIVE: To establish length of the affected nerve segment (LANS) in ulnar neuropathy at the elbow (UNE). METHODS: In a group of our previously reported UNE patients we identified 2-cm segments with reduced motor nerve conduction velocity (MNCV) on electrodiagnostic (EDx) studies and increased nerve cross-sectional areas (CSA) on ultrasonographic (US) studies. LANS was obtained by summation of these abnormal 2-cm segments separately for each approach. We also studied effect of selected independent parameters on LANS. RESULTS: Altogether we studied 189 patients (194 arms). Mean (SD) LANS determined in 171 arms with reduced ulnar MNCV was 4.15 (1.89) cm, and was similar (p = 0. 21) to LANS obtained in 147 arms with increased CSA 4.46 (2.29) cm. Longer LANS were found in right arms, clinically severe UNE, axonal UNE and UNE due to entrapment. The most commonly affected 6 cm segment included 89% of abnormal 2-cm segments, with 50% of included 2-cm segments being normal. By contrast, the whole 10 cm segment included all abnormal 2-cm segments, with 66% of included segments being normal. CONCLUSIONS: In UNE both EDx and US studies revealed average LANS of around 4 cm. LANS was longer in more severe UNE. SIGNIFICANCE: LANS needs to be taken into account in discussion of the mechanisms of UNE and approach to EDx diagnosis of UNE, particularly length of the segment used in nerve conduction studies across the elbow.

Application of digital infrared thermography for carpal tunnel syndrome evaluation.

We investigated the thermographic findings of carpal tunnel syndrome (CTS). We enrolled 304 hands with electrodiagnostically identified CTS and 88 control hands. CTS hands were assigned to duration groups (D1, < 3 months; D2, 3‒6 months; D3, 6‒12 months; D4, ≥ 12 months) and severity groups (S1, very mild; S2, mild; S3, moderate; S4, severe). The temperature difference between the median and ulnar nerve territories (ΔM-U territories) decreased as CTS duration and severity increased. Significant differences in ΔM-U territories between the D1 and D3, D1 and D4, D2 and D4, and S1 and S4 groups (P = 0.003, 0.001, 0.001, and < 0.001, respectively) were observed. Thermal anisometry increased as CTS duration and severity increased. Significant differences in thermal anisometry between the D1 and D4 as well as the D2 and D4 groups (P = 0.005 and 0.04, respectively) were noted. Thermal anisometry was higher in the S4 group than in the S1, S2, and S3 groups (P = 0.009, < 0.001, and 0.003, respectively). As CTS progresses, skin temperature tends to decrease and thermal variation tends to increase in the median nerve-innervated area. Thermographic findings reflect the physiological changes of the entrapped median nerve.

MicroRNAs as Biomarkers of Charcot-Marie-Tooth Disease Type 1A.

OBJECTIVE: To determine whether microRNAs (miRs) are elevated in the plasma of individuals with the inherited peripheral neuropathy Charcot-Marie-Tooth disease type 1A (CMT1A), miR profiling was employed to compare control and CMT1A plasma. METHODS: We performed a screen of CMT1A and control plasma samples to identify miRs that are elevated in CMT1A using next-generation sequencing, followed by validation of selected miRs by quantitative PCR, and correlation with protein biomarkers and clinical data: Rasch-modified CMT Examination and Neuropathy Scores, ulnar compound muscle action potentials, and motor nerve conduction velocities. RESULTS: After an initial pilot screen, a broader screen confirmed elevated levels of several muscle-associated miRNAs (miR1, -133a, -133b, and -206, known as myomiRs) along with a set of miRs that are highly expressed in Schwann cells of peripheral nerve. Comparison to other candidate biomarkers for CMT1A (e.g., neurofilament light) measured on the same sample set shows a comparable elevation of several miRs (e.g., miR133a, -206, -223) and ability to discriminate cases from controls. Neurofilament light levels were most highly correlated with miR133a. In addition, the putative Schwann cell miRs (e.g., miR223, -199a, -328, -409, -431) correlate with the recently described transmembrane protease serine 5 (TMPRSS5) protein biomarker that is most highly expressed in Schwann cells and also elevated in CMT1A plasma. CONCLUSIONS: These studies identify a set of miRs that are candidate biomarkers for clinical trials in CMT1A. Some of the miRs may reflect Schwann cell processes that underlie the pathogenesis of the disease. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that a set of plasma miRs are elevated in patients with CMT1A.

Bi-allelic loss of function variants in COX20 gene cause autosomal recessive sensory neuronopathy.

Sensory neuronopathies are a rare and distinct subgroup of peripheral neuropathies, characterized by degeneration of the dorsal root ganglia neurons. About 50% of sensory neuronopathies are idiopathic and genetic causes remain to be clarified. Through a combination of homozygosity mapping and whole exome sequencing, we linked an autosomal recessive sensory neuronopathy to pathogenic variants in the COX20 gene. We identified eight unrelated families from the eastern Chinese population carrying a founder variant c.41A>G (p.Lys14Arg) within COX20 in either a homozygous or compound heterozygous state. All patients displayed sensory ataxia with a decrease in non-length-dependent sensory potentials. COX20 encodes a key transmembrane protein implicated in the assembly of mitochondrial complex IV. We showed that COX20 variants lead to reduction of COX20 protein in patient's fibroblasts and transfected cell lines, consistent with a loss-of-function mechanism. Knockdown of COX20 expression in ND7/23 sensory neuron cells resulted in complex IV deficiency and perturbed assembly of complex IV, which subsequently compromised cell spare respiratory capacity and reduced cell proliferation under metabolic stress. Consistent with mitochondrial dysfunction in knockdown cells, reduced complex IV assembly, enzyme activity and oxygen consumption rate were also found in patients' fibroblasts. We speculated that the mechanism of COX20 was similar to other causative genes (e.g. SURF1, COX6A1, COA3 and SCO2) for peripheral neuropathies, all of which are functionally important in the structure and assembly of complex IV. Our study identifies a novel causative gene for the autosomal recessive sensory neuronopathy, whose vital function in complex IV and high expression in the proprioceptive sensory neuron further underlines loss of COX20 contributing to mitochondrial bioenergetic dysfunction as a mechanism in peripheral sensory neuron disease.

Enhancing diagnostic accuracy using a side-to-side cross-sectional area ratio for the diagnosis of unilateral ulnar mononeuropathy at the elbow.

INTRODUCTION: Neuromuscular ultrasonography (NMUS) is a valuable adjunct to electrodiagnostic testing for the diagnosis of entrapment neuropathy. The aim of this study was to determine whether diagnostic accuracy of NMUS could be enhanced in patients with unilateral ulnar mononeuropathy at the elbow (UNE) by utilizing side-to-side ulnar nerve cross-sectional area (CSA) ratios. METHODS: Retrospective case-control analysis of unilateral UNE cases identified cutoff values for elbow segment ulnar nerve maximum CSA (MCSA) of the symptomatic/asymptomatic limb (M ratio), as well as side-to-side ratios comparing MCSA with ipsilateral CSA at the Guyon canal (E/G), middle forearm (E/F), and middle humerus (E/H). Diagnostic accuracy values were calculated. RESULTS: The optimal M-ratio cut-off was 1.22 (sensitivity, 92.9%; specificity, 97.8%; accuracy, 95.4%). Optimal cutoffs for inter-E/G, -E/F, and -E/H ratios were 1.07 (sensitivity, 98%; specificity, 78%; accuracy, 87.7%), 1.11 (sensitivity, 95%; specificity, 80%; accuracy, 87.2%), and 1.18 (sensitivity, 95%; specificity, 93%; accuracy, 94%), respectively. DISCUSSION: The M ratio and inter-E/H ratio exhibited high diagnostic accuracy for unilateral UNE. Prospective studies are needed to compare the accuracy of the new measures with a single MCSA measurement.

Patterns and parameters describing nerve thickening in compression and entrapment ulnar neuropathies at the elbow.

OBJECTIVE: To compare pattern and parameters describing nerve thickening in ulnar neuropathy at the elbow (UNE) due to external compression in the retrocondylar groove (RTC), and entrapment under the humeroulnar aponeurosis (HUA). METHODS: In a group of our previously reported UNE patients we ultrasonographically (US) measured ulnar nerve cross-sectional areas (CSA) on 6-8 standard locations in the elbow segment. We compared CSA patterns in both groups, and determined diagnostic utility of selected CSA based parameters. RESULTS: We studied 79 patients (81 arms) with UNE due to external compression, and 53 patients (55 arms) due to entrapment. Maximal ulnar nerve CSA (>16 mm2), maximal CSA change (>7 mm2/1-2 cm) and maximal/minimal CSA ratio (>2.6) were significantly larger in UNE due to entrapment. They also differentiated these arms from arms with compression with sensitivities of 78%, 87% and 80%, and specificities of 90%, 94%, and 85%, respectively. CONCLUSION: Maximal difference in CSA between points separated by 1-2 cm (>7 mm2/1-2 cm) very efficiently differentiated between UNE due to external compression and entrapment. SIGNIFICANCE: The proposed parameter will hopefully complement precise localization in determining underlying mechanism of UNE. This may help physicians to determine the most appropriate treatment for UNE and possibly other focal neuropathies of unknown cause; i.e., conservative treatment for external compression and surgery for entrapment.

Ultrasonography in Distal Ulnar Nerve Neuropathy: Findings in 33 Patients.

PURPOSE: Although there are many case reports on the role of ultrasonography (US) in distal ulnar nerve neuropathy (Guyon canal syndrome), there is a paucity of large series in the literature because of its rarity. During an 8-year period, 33 instances of electrodiagnostically confirmed cases underwent US imaging. These cases were analyzed to determine the role of US in uncovering the cause of distal ulnar nerve neuropathy and its contribution to further management. METHODS: This was a retrospective study of patients diagnosed with distal ulnar nerve neuropathy based on electrodiagnostic criteria, who also had undergone US (measurement of the cross-sectional area and documentation of causes such as cysts and neuromas). RESULTS: US showed normal ulnar nerve in 5, cysts in 10, neuromas in 2, and nonspecific enlargement in 16 patients. Surgery was performed in 15 patients, and the US findings were corroborated in those with cysts and neuromas; 1 patient had an aberrant muscle, and two had fibrous bands constricting the ulnar nerve in the Guyon canal (not detected preoperatively by US imaging). CONCLUSIONS: US imaging detected the underlying cause of distal ulnar nerve neuropathy in a significant percentage of patients, potentially contributing to effective treatment.

Electrophysiological testing in chronic inflammatory demyelinating polyneuropathy patients treated with subcutaneous immunoglobulin: The Polyneuropathy And Treatment with Hizentra (PATH) study.

OBJECTIVE: To assess electrophysiology parameters that can reflect patients' clinical status and show changes in nerve function with treatment, in a study of subcutaneous immunoglobulin in chronic inflammatory demyelinating polyneuropathy. METHODS: Nerve conduction studies (latency, conduction velocity, conduction block and compound muscle action potential [CMAP] on upper limb median, ulnar, and lower limb peroneal motor nerves) were conducted in the placebo-controlled PATH (Polyneuropathy And Treatment with Hizentra) study of two doses of maintenance subcutaneous immunoglobulin (SCIG) IgPro20 in CIDP. RESULTS: Averaged proximal latency substantially increased with placebo (+1.1 ms) indicating electrophysiologic deterioration but remained stable with IgPro20 (0.2 g/kg bodyweight [bw]: +0.1 ms; 0.4 g/kg bw: -0.1 ms). Distal latencies were also more prolonged with placebo versus IgPro20. Averaged motor nerve conduction velocity substantially decreased with placebo (-1.6 m/s) versus increasing in both IgPro20 groups (+0.2 m/s and +1.0 m/s, respectively). Conduction block and CMAP amplitudes did not change substantially. CONCLUSION: These findings support the effectiveness of maintenance IgPro20, as nerve function changed in the direction of increasing nerve dysfunction with placebo but remained stable with ongoing IgPro20 therapy. SIGNIFICANCE: Electrophysiology testing can support assessment of clinical status in CIDP to determine treatment efficacy.

Temporal evolution of nerve conduction study abnormalities in anti-myelin-associated glycoprotein neuropathy.

BACKGROUND: A distal-predominant demyelinating symmetric pattern is most frequent in patients with neuropathy associated with anti-myelin-associated glycoprotein (MAG) antibodies. The literature however lacks longitudinal data to describe whether this is consistent over time. METHODS: From the Ottawa Neuromuscular Center database, we identified 23 patients with both immunoglobulin M gammopathy and anti-MAG antibodies. For median, ulnar and fibular motor conduction studies, we analyzed distal latency and amplitude, negative peak duration, terminal latency index (TLI), and conduction velocity. For median, ulnar, sural, and superficial fibular sensory conduction studies, we analyzed distal latency and amplitude. Results were compared for the earliest and the latest data sets. RESULTS: The mean time interval between the two assessment points was 6.5 years. Median and ulnar motor nerve conduction studies did not show a significant change for any of the parameters tested. There was disproportionate prolongation of median distal motor latency and reduction in TLI, compared to the ulnar nerve. Deep fibular motor conduction studies showed a marked reduction in amplitudes over time. Sensory potentials were recordable in the upper limb in less than 50% at the first study and less than 25% on the most recent study. There was an even larger attrition of recordable sural and superficial fibular sensory potentials. CONCLUSIONS: Our results highlight the stability of median and ulnar motor conduction study results over a mean observation period of 6.5 years. In contrast, lower limb motor and all sensory potentials show a marked trend toward becoming unrecordable.

Correlates of Fatigability in Patients With Spinal Muscular Atrophy.

OBJECTIVE: To determine the associations between fatigability and muscle strength, motor function, neuromuscular junction (NMJ) function, and perceived fatigue in spinal muscular atrophy (SMA), we assessed 61 patients with SMA. METHODS: Fatigability was defined as the inability to continue a 20-minute submaximal repetitive task of either walking or proximal or distal arm function and expressed as drop-out on the Endurance Shuttle Test Combined Score (ESTCS). We assessed muscle strength with the Medical Research Council (MRC) sum score, motor function with the Hammersmith Functional Motor Scale Expanded (HFMSE) and Motor Function Measure (MFM), NMJ function with repetitive nerve stimulation of the accessory and ulnar nerve, and perceived fatigue with the PROMIS Fatigue Short Form questionnaire in 61 children and adults with SMA types 2-4. We applied Cox regression analysis to explore the associations between fatigability and these factors. RESULTS: The hazard of drop-out on the ESTCS decreased 0.8%, 2%, and 1.3% for each point increase in the MRC sum score, the HFMSE score, and the MFM percentual score, respectively. However, we observed prominent fatigability with preserved muscle function and vice versa in 13%-16% of patients. We did not find an association between NMJ dysfunction of the accessory (p = 0.37) and ulnar nerve (p = 0.063) and fatigability, which could be due to a large number of missing values. Perceived fatigue in SMA was comparable to reference values and was not associated with fatigability (p = 0.52). CONCLUSION: Fatigability in SMA is associated with, yet not equivalent to, muscle strength and motor function.

Is simple decompression enough for the treatment of idiopathic cubital tunnel syndrome: A prospective comparative study analyzing the outcomes of simple decompression versus partial medial epicondylectomy.

OBJECTIVES: This study aims to compare the clinical and functional outcomes of simple in-situ decompression and partial medial epicondylectomy for the treatment of idiopathic cubital tunnel syndrome (CuTS). PATIENTS AND METHODS: Between March 2014 and December 2016, 71 patients (31 males, 40 females; mean age 46.7 years; range, 38 to 62 years) with CuTS scheduled to undergo simple in-situ decompression (group 1) or partial medial epicondylectomy (group 2) were prospectively reviewed. All patients were analyzed with clinical examination (Tinel sign, Froment's and Wartenberg's signs, elbow flexion test, subluxation), and McGowan scores before and after surgery. Final outcomes were reviewed with Wilson and Krout grading system. RESULTS: There was no significant difference between the study groups in regard to Wilson and Krout grading and McGowan scores postoperatively. Group 1 had significantly better grip and key pinch strength values compared to group 2 at the final follow-up control. CONCLUSION: In-situ decompression and partial medial epicondylectomy represent efficient and safe methods for the treatment of idiopathic CuTS. When their efficiency is compared, in-situ decompression had better grip and key pinch strength values and more excellent outcomes compared to partial medial epicondylectomy.

Sensitivity and specificity of repetitive nerve stimulation with lower cutoffs for abnormal decrement in myasthenia gravis.

INTRODUCTION: The sensitivity of repetitive nerve stimulation (RNS) in myasthenia gravis (MG) is dependent on the cutoff for abnormal decrement. METHODS: RNS data of adults with and without MG from 2014 to 2017 were reviewed retrospectively. The maximum reliable RNS amplitude/area decrement before and after exercise from facial, spinal accessory (SA), ulnar, and fibular nerves was recorded. Sensitivity/specificity using 5%, 7%, and 10% cutoffs were calculated. RESULTS: Seventy-nine of 141 patients had MG (46 generalized, 21 ocular, 12 bulbar). A total of 608 unique RNS recordings were analyzed. Overall RNS sensitivity/specificity at ≥5%, ≥7%, and ≥10% amplitude cutoffs were as follows: SA, 65.6%/86.3%, 49.2%/94.1%, and 29.5%/96.1%; facial, 51.0%/82.5%, 43.1%/95.0%, and 37.3%/100%; ulnar, 43.6%/100%, 41.0%/100%, and 41.0%/100%; and fibular, 52.6%/89.5%, 42.1%/94.7%, and 42.1%/100%. DISCUSSION: Lowering amplitude cutoff from 10% to 7% increased or maintained sensitivity with little loss in specificity. Post-exercise and area analysis resulted in increased sensitivity in some circumstances.

Autonomic nervous system may be affected after carpal tunnel syndrome surgery: A possible mechanism for persistence of symptoms after surgery.

Background and purpose: After carpal tunnel surgery, some patients report complaints such as edema, pain, and numbness. Purpose - The aim of this study was to evaluate autonomic nervous system function in patients with a history of carpal tunnel surgery using sympathetic skin response (SSR). Methods: Thirty three patients (55 ±10 years old) with a history of unilateral operation for carpal tunnel syndrome were included in the study. The SSR test was performed for both hands. Both upper extremities median and ulnar nerve conduction results were recorded. Results: A reduced amplitude (p=0.006) and delayed latency (p<0.0001) were detected in the SSR test on the operated side compared to contralateral side. There was no correlation between SSR and carpal tunnel syndrome severity. Conclusion: Although complex regional pain syndrome does not develop in patients after carpal tunnel surgery, some of the complaints may be caused by effects on the autonomic nervous system.