Ulnar Motor Research Articles

Feasibility of a less invasive supercharged end-to-side anterior interosseous nerve to ulnar motor nerve transfer.

The object of this study was to perform an anatomical dissection of Thiel-embalmed specimens in a step-by-step procedure, to establish a 'safe zone' in which to perform a less invasive supercharged end-to-side (SETS) anterior interosseous nerve to ulnar motor nerve transfer without tension and to demonstrate its feasibility. The sample size was calculated with a 5 mm error to reach a 95% confidence interval. Dissection was performed in 15 specimens and the 'safe zone' was established between 40 and 90 mm proximal to the pisiform. Several surgical tips are recommended to help complete the procedure. A reproducible 'safe zone' was found for performing a SETS anterior interosseous to ulnar motor nerve transfer with 95% certainty, reducing soft tissue damage and enhancing the original surgical technique.

Whether coagulation dysfunction influences the onset and progression of diabetic peripheral neuropathy: A multicenter study in middle-aged and aged patients with type 2 diabetes.

Nearly half of patients with diabetes experience diabetic peripheral neuropathy (DPN), resulting in a mere 53% survival rate within 3 years. Aberrations in coagulation function have been implicated in the pathogenesis of microvascular complications, prompting the need for a thorough investigation into its role as a contributing factor in the development and progression of DPN. Data were gathered from 1211 type 2 diabetes patients admitted to five centers from September 2018 to October 2022 in China. DPN was evaluated by symptoms and electromyography. Motor and sensory nerve conduction velocity (NCV) was appraised and the NCV sum score was calculated for the median, ulnar, and peroneal motor or sensory nerves. Patients with DPN exhibited alterations in coagulation function. (i) Specifically, they exhibited prolonged thrombin time (p = 0.012), elevated fibrinogen (p < 0.001), and shortened activated partial thromboplastin time (APTT; p = 0.026) when compared to the control group. (ii) After accounting for potential confounders in linear regression, fibrinogen, and D-dimer were negatively related to the motor NCV, motor amplitude values, and mean velocity and amplitude. Also, fibrinogen was associated with higher Michigan neuropathy screening instrument (MNSI) scores (β 0.140; p = 0.001). This result of fibrinogen can be validated in the validation cohort with 317 diabetic patients. (iii) Fibrinogen was independently associated with the risk of DPN (OR 1.172; p = 0.035). In the total age group, DPN occurred at a slower rate until the predicted fibrinogen level reached around 3.75 g/L, after which the risk sharply escalated. Coagulation function is warranted to be concerned in patients with type 2 diabetes to predict and prevent the occurrence of DPN in clinical practice.

Ultrasound Measurements of the Ulnar Nerve at the Medial Epicondyle Correlate With Electrodiagnostic Studies.

Cubital tunnel syndrome is the second most common compressive neuropathy in the upper extremity and is commonly evaluated with electrodiagnostic studies (EDS). Ultrasound (US) has emerged as a potentially more efficient alternative to EDS. The purpose of this study is to evaluate whether measurements of the cross-sectional area (CSA) of the ulnar nerve at the elbow correlate with EDS results. This study was a prospective analysis of patients who presented with signs and symptoms consistent of cubital tunnel syndrome, who received USs of the ulnar nerve at the elbow and nerve conduction tests. Pearson correlation coefficients were used to evaluate the correlation between ulnar nerve CSA and electrodiagnostic data. t Tests were used to evaluate statistical differences between the mean ulnar nerve CSA of patients with positive or negative nerve conduction study results. Youden Index was used to calculate the optimal cut-off point for US CSA based on maximal sensitivity and specificity. Statistical significance was based on a two-sided P less than .05. The association between increasing US CSA at the medial epicondyle with slowing of the conduction velocity of the ulnar motor nerve across the elbow was statistically significant (r = -0.35, P = .02). Patients with positive EDS tests had significantly larger nerve size than those with negative tests (all Ps < .03). A cut-off point of greater than or equal to 11 mm2 had a sensitivity of 70.83% and specificity of 66.67%. Larger ulnar nerve CSAs correlate with slowing of the conduction velocity on EDSs, and those with positive EDSs have larger nerve sizes than those with negative tests.

Upper Extremity Nerve Transfers for Treatment of Nerve Injury After Cervical Spine Surgery: A Single-Center Retrospective Review.

Nerve transfers to restore or augment function after spinal cord injury is an expanding field. There is a paucity of information, however, on the use of nerve transfers for patients having undergone spine surgery. The incidence of neurologic deficit after spine surgery is rare but extremely debilitating. The purpose of this study was to describe the functional benefit after upper extremity nerve transfers in the setting of nerve injury after cervical spine surgery. A single-center retrospective review of all patients who underwent nerve transfers after cervical spine surgery was completed. Patient demographics, injury features, spine surgery procedure, nerve conduction and electromyography study results, time to referral to nerve surgeon, time to surgery, surgical technique and number of nerve transfers performed, complications, postoperative muscle testing, and subjective outcomes were reviewed. Fourteen nerve transfers were performed in 6 patients after cervical spine surgery. Nerve transfer procedures consisted of a transfer between a median nerve branch of flexor digitorum superficialis into a biceps nerve branch, an ulnar nerve branch of flexor carpi ulnaris into a brachialis nerve branch, a radial nerve branch of triceps muscle into the axillary nerve, and the anterior interosseous nerve into the ulnar motor nerve. Average patient age was 55 years; all patients were male and underwent surgery on their left upper extremity. Average referral time was 7 months, average time to nerve transfer was 9 months, and average follow-up was 21 months. Average preoperative muscle grading was 0.9 of 5, and average postoperative muscle grading was 4.1 of 5 ( P < 0.00001). Upper extremity peripheral nerve transfers can significantly help patients regain muscle function from deficits secondary to cervical spine procedures. The morbidity of the nerve transfers is minimal with measurable improvements in muscle function.

Ulnar Motor Nerve Conduction Recorded from Two Sites in Patients with and Without Ulnar Neuropathy at the Elbow.

Ulnar Motor Nerve Conduction Recorded from Two Sites in Patients with and Without Ulnar Neuropathy at the Elbow.

Gene Distribution in Pediatric-Onset Inherited Peripheral Neuropathy: A Single Tertiary Center in Thailand.

Inherited peripheral neuropathy presents a diagnostic and therapeutic challenge due to its association with mutations in over 100 genes. This condition leads to long-term disability and poses a substantial healthcare burden on society. This study aimed to investigate the distribution of genes and establish the genotype-phenotype correlations, focusing on pediatric-onset cases. Exome sequencing and other analytical techniques were employed to identify pathogenic variants, including duplication analysis of the PMP22 gene. Each patient underwent physical examination and electrophysiological studies. Genotypes were correlated with phenotypic features, such as age at disease onset and ulnar motor nerve conduction velocity. We identified 35 patients with pediatric-onset inherited peripheral neuropathy. Pathogenic or likely pathogenic variants were confirmed in 24 out of 35 (68.6%) patients, with 4 of these variants being novel. A confirmed molecular diagnosis was achieved in 90.9% (10/11) of patients with demyelinating Charcot-Marie-Tooth disease (CMT) and 56.3% (9/16) of patients with axonal CMT. Among patients with infantile-onset CMT (≤2 years), the most common causative genes were MFN2 and NEFL, while GDAP1 and MFN2 were frequent causes among patients with childhood- or adolescent-onset CMT (3-9 years). The MFN2 gene was the most commonly implicated gene, and the axonal type was predominant in this cohort of Thai patients with pediatric-onset inherited peripheral neuropathy.

Rare Median Nerve and Digital Nerve Tumor Resection and Distal Nerve Transfers: A Report of 2 Cases.

We present 2 cases of median nerve reconstruction using distal nerve transfers after resection of unusual benign median nerve tumors. Critical sensation was restored in case 1 by transferring the fourth common digital nerve to first web digital nerves. Thumb opposition was regained by transferring the abductor digiti minimi ulnar motor nerve branch to the recurrent median motor nerve branch. Critical sensation was restored in case 2 by transferring the long finger ulnar digital nerve to the index finger radial digital nerve. Distal nerve transfers, even with short grafts, are reliable median nerve deficit treatments, sparing the need for larger autologous nerve grafts and late tendon opponensplasties.

Long-Term Evaluation of Ulnar Nerve Function in Patients with Distal Humerus Fractures Treated with Open Reduction and Internal Fixation: A Nerve Conduction Study.

To investigate the long-term evaluation with electromyography of ulnar nerve function in patients with distal humerus fractures (DHFs) treated with open reduction and internal fixation. Retrospective cohort study. Level 1 trauma center. Fifty-two patients (20 men and 32 women) with DHFs. All patients underwent open reduction and internal fixation between 2002 and 2017 with a minimum five years' follow-up. The nerve conduction test was done for evaluation ulnar nerve function. Secondary outcomes were modified McGowan grading system for symptoms of ulnar neuropathy. The mean follow-up time was 112.7 ± 39 months after surgery. 28.8% (15) of the patients scored in Grade I, 30 (57.6%) in Grade II, and 7 (13.6%) in Grade III on the affected side according to McGowan grading scale. According to EMG results, 40.1% (21/52) of patients had abnormal results. There was significant difference between fracture and unaffected side regarding ulnar nerve motor wrist CMAP amplitude, motor below elbow CMAP amplitude, above elbow CMAP amplitude, above elbow MNCV, and sensory wrist amplitude. Ulnar nerve motor wrist-ADM latency (p = 0.01; r = 0.446) and ulnar nerve sensory conduction velocity (p < 0.001, r = -0.504) were significant correlation with McGowan grading scale. There were significant difference ulnar nerve motor amplitude and sensory wrist amplitude between fracture and unaffected side. A mean decrease in sensory amplitude of fracture elbow was found 25% compared to the unaffected side in our result. Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Relationship Between Clinical Outcomes and Nerve Conduction Studies Before and After Viral Infections in Healthy Individuals: Case Series.

The neurological effect of viral respiratory infections has been acknowledged in many studies.However, patients who recovered from this infection show neurological manifestations and are not being routinely transferred for electrodiagnostic evaluation. This study aimed to examine the neurological effect of viral respiratory infections on the nerve function using electrophysiology in patients fully recovered from viral respiratory infections. To limit bias in the results, the authors decided to choose patients who recovered from one virus in all participants (coronavirus).Medical records were screened for patients who performed nerve conduction studies (NCSs) before the coronavirus pandemic.Thirty patients met our inclusion criteria, and only 10 showed up to perform NCS.Data of the NCS was compared before and after the coronavirus infection for motor and sensory NCS parameters. An increase in both the median and ulnar sensory nerve latencies and a decrease in the sensory nerve amplitude was observed.Also, there was a decrease in the motor conduction velocity (MCV) of the ulnar nerves and motor amplitude in the median nerve.In the lower limbs, there was a decrease in the sural nerve latency, increased MCV in the tibial nerves, and decreased MCV in the peroneal nerves.The proximal amplitudes of the tibial and peroneal nerves were increased, but the distal amplitude was increased only in the peroneal nerves and decreased in the tibial nerves. There is a significant impact of viral infections on the peripheral nerves.Large-scale prospective studies are required to investigate the pathogenesis of the neuropathy and myopathy after viral infections.

Psychophysiological and Neurophysiological Correlates of Dropping Objects from Hands in Carpal Tunnel Syndrome.

Dropping objects from hands (DOH) is a common symptom of carpal tunnel syndrome (CTS). We evaluated the clinical, neurophysiological, and psychophysiological features of 120 CTS patients to elucidate the DOH pathophysiology. Forty-nine healthy controls were included. In the patients, the Boston Carpal Tunnel Questionnaire (BCTQ), the Douleur Neuropathique 4 questions (DN4), and a numeric rating scale for pain (NRS) were evaluated. In patients and controls, we evaluated bilateral median and ulnar motor and sensory nerve conduction studies, cutaneous silent period and cutaneomuscular reflexes (CMR) of the abductor pollicis brevis, cold-detection threshold (CDT) and heat-pain detection threshold (HPT) at the index, little finger, and dorsum of the hand, and vibratory detection threshold at the index and little finger by quantitative sensory testing. CTS with DOH had higher BCTQ, DN4 and NRS, lower median sensory action potential, longer CMR duration, lower CDT and higher HPT at all tested sites than controls and CTS without DOH. Predictive features for DOH were abnormal CDT and HPT at the right index and dorsum (OR: 3.88, p: 0.03) or at the little finger (OR: 3.27, p: 0.04) and a DN4 higher than 4 (OR: 2.16, p < 0.0001). Thermal hypoesthesia in median and extra-median innervated territories and neuropathic pain are predictive of DOH in CTS.

Proximity of the Ulnar Neurovascular Structures in Endoscopic Carpal Tunnel Release Surgery: A Cadaveric Study

To evaluate the proximity of the ulnar neurovascular structures to the endoscopic blade during endoscopic carpal tunnel release (CTR). Ten fresh-frozen cadaver hands were used to perform endoscopic CTR using devices from two manufacturers. The skin was excised from the palm, and the endoscopic carpal tunnel blade was deployed at the distal edge of the transverse carpal ligament (TCL). The blade's proximity to the ulnar neurovascular bundle, deep ulnar motor branch, superficial palmar arch, and median nerve was recorded. Following release of the TCL, the device was turned ulnar to the maximal extent to determine if direct injury to the ulnar neurovascular bundle was possible. The average longitudinal distance from the end of the TCL to the superficial palmar arch was 13.3 mm (range, 8.4-20.9) and to the ulnar motor branch was 10.8 mm (range, 4.0-15.0). The average transverse distance from the end of the TCL to the ulnar neurovascular bundle was 5.9 mm (range, 3.1-7.8) and to the median nerve was 3.3 mm (range, 0-6.5). In two of our specimens, the median nerve subluxated volarly over the cutting device. When placing the blade at the distal edge of the TCL, injury to the deep motor branch of the ulnar nerve, ulnar neurovascular bundle, or superficial palmar arch was not possible in any specimens using the tested devices, even when turning the blade directly toward these structures. There is a low likelihood of direct injury to the ulnar neurovascular bundle during endoscopic CTR. These results suggest that injury to the ulnar neurovascular bundle is unlikely during endoscopic CTR if the distal aspect of the transverse carpal ligament can be clearly identified prior to release. Control of the median nerve is also important to prevent subluxation over the cutting device.

Anterior Interosseus to Ulnar Motor Nerve Transfers: A Canadian Perspective.

The anterior interosseus nerve (AIN) to ulnar motor nerve transfer has been popularized as an adjunct to surgical decompression in patients with severe cubital tunnel syndrome (CuTS) and high ulnar nerve injuries. The factors influencing its implementation in Canada have yet to be described. An electronic survey was distributed to all members of the Canadian Society of Plastic Surgery (CSPS) using REDCap software. The survey examined 4 themes: previous training/experience, practice volume of nerve pathologies, experience with nerve transfers, and approach to the treatment of CuTS and high ulnar nerve injuries. A total of 49 responses were collected (12% response rate). Of all, 62% of surgeons would use an AIN to ulnar motor supercharge end-to-side (SETS) transfer for a high ulnar nerve injury. For patients with CuTS and signs of intrinsic atrophy, 75% of surgeons would add an AIN-SETS transfer to a cubital tunnel decompression. Sixty-five percent would also release Guyon's canal, and the majority (56%) use a perineurial window for their end-to-side repair. Eighteen percent of surgeons did not believe the transfer would improve outcomes, 3% cited lack of training, and 3% would preferentially use tendon transfers. Surgeons with hand fellowship training and those less than 30 years in practice were more likely to use nerve transfers in the treatment of CuTS (P < .05). Most CSPS members would use an AIN-SETS transfer in the treatment of both a high ulnar nerve injury and severe CuTS with intrinsic atrophy.

Nerve conduction studies through landmark based recording and effects of hand length

As per existing guidelines, the distance between stimulator and recording electrodes in nerve conduction studies (NCS) should be the same (fixed) in all the subjects, i.e., it should not be based on anatomical landmarks. However, there are no studies comparing fixed distance recordings with landmark based NCS. We postulated that hand length can influence the NCS parameters in fixed distance recordings and this can be nullified using landmark based recordings. To test this theory, we performed NCS in 48 normal subjects as per standard guidelines (standard protocol) and then compared it to NCS with ulnar styloid as the landmark (modified protocol). NCS were performed on median and ulnar nerves of the right upper limb. Three motor NCS parameters including distal latency, compound muscle action potential (CMAP) amplitudes and nerve conduction velocities were measured. Sensory nerve action potential (SNAP) amplitudes and conduction velocities were the two sensory parameters measured. On analysis, ulnar motor conduction velocity was the only parameter affected by hand length in both standard and modified protocols. Modified protocol did not have any additional advantage to the standard protocol advised by NDTF. We conclude that the NDTF guidelines are therefore reasonable when considering the effects of hand length. Possible reasons for this result including anatomical and anthropometric explanations are discussed.

SP04. Abductor Digiti Minimi Turbocharged End-to-side Nerve Transfer is a Novel Technique to Restore Ulnar Motor Function

SP04. Abductor Digiti Minimi Turbocharged End-to-side Nerve Transfer is a Novel Technique to Restore Ulnar Motor Function

Outstripping of Motor Unit Compensation with Disease Severity in Adults with Spinal Muscular Atrophy (P3-8.009)

<h3>Objective:</h3> To determine relationships between ulnar (hypothenar) multipoint incremental motor unit number estimation (MUNE), single motor unit potential amplitude (SMUP), and compound motor unit potential amplitude (CMAP) versus measures of disease severity in ambulatory (A-SMA) vs non-ambulatory (N-SMA) adults with spinal muscular atrophy (SMA). <h3>Background:</h3> MUNE is an estimate of the number of functioning motor neurons innervating a muscle(s), and SMUP provides an index of motor unit size. Here, we investigated the relationship between MUNE and CMAP in A-SMA versus N-SMA. <h3>Design/Methods:</h3> Cross sectional analysis of electrophysiological and functional outcome data obtained in ambulatory (n=15) and non-ambulatory (n=25) untreated adults with SMA. <h3>Results:</h3> Mean CMAP amplitude for A-SMA vs N-SMA were 8.74 ± 1.82 and 2.37 ± 2.3 (p&lt;0.001). Mean MUNE for A-SMA vs N-SMA were 102.53 ± 30.44 and 34.65 ± 31.83 (p&lt;0.001). Mean SMUP for A-SMA vs N-SMA were 86.3 ± 18.1 and 91.93 ± 37.09 (p=0.96). There was good correlation in N-SMA between MUNE and CMAP (r = 0.93, p&lt;0.001), CMAP and Hammersmith rating scale (r = 0.645, p&lt;0.001), MUNE and Hammersmith rating scale (r = 0.5405, p&lt;0.05), U-CMAP and % Predicted FVC (r = 0.771, p&lt;0.001), MUNE and % Predicted FVC (r = 0.7417, p=0.001). In contrast, these measures did not correlate in A-SMA. <h3>Conclusions:</h3> MUNE and CMAP are useful measures in SMA showing strong correlation with severity and other measures of function. SMUP, a measure of motor unit size providing an index of motor neuron compensation following denervation, did not demonstrate the ability to distinguish severity in adults with SMA. These findings suggest that motor unit compensation is outstripped by motor unit loss across the spectrum of SMA and that motor unit size may an important functional determinant with more severe phenotype. <b>Disclosure:</b> Dr. Deardorff has nothing to disclose. Dr. Guerra Castanon has nothing to disclose. Ms. Zhao has nothing to disclose. Dr. Kelly has nothing to disclose. Marco Tellez has nothing to disclose. Ms. Heintzman has nothing to disclose. Dr. Kolb has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for AveXis. Dr. Kolb has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for CureSMA. The institution of Dr. Kolb has received research support from NIH. The institution of Dr. Kolb has received research support from AveXis. The institution of Dr. Kolb has received research support from NIH. Dr. Arnold has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Genentech. Dr. Arnold has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for La Hoffmann Roche. Dr. Arnold has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Cadent Therapeutics . Dr. Arnold has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for Novartis. The institution of Dr. Arnold has received research support from NIH. The institution of Dr. Arnold has received research support from NMD Pharma. The institution of Dr. Arnold has received research support from Gilead Sciences. The institution of Dr. Arnold has received research support from CureSMA. Dr. Arnold has received intellectual property interests from a discovery or technology relating to health care. Dr. Elsheikh has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Biogen . Dr. Elsheikh has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Argnex . The institution of Dr. Elsheikh has received research support from Biogen. The institution of Dr. Elsheikh has received research support from Cure SMA.

Clinical and Electrophysiological Characteristics of Very Early Guillain-Barré Syndrome.

This study compared the clinical and electrodiagnostic (EDX) features and long-term outcomes of patients with very early Guillain-Barré syndrome (VEGBS, duration of illness ≤4 days) and those with early/late (>4 days)-presenting GBS. One hundred patients with GBS were clinically evaluated and categorized into VEGBS and early/late GBS groups. Electrodiagnostic studies were performed on the bilateral median, ulnar, and fibular motor nerves and the bilateral median, ulnar, and sural sensory nerves. Admission and peak disability were assessed using the 0 to 6 Guillain-Barré Syndrome Disability Scale (GBSDS). The primary outcome was disability at 6 months, which was categorized as complete (GBSDS ≤1) or poor (GBSDS ≥2). The secondary outcomes were frequencies of abnormal electrodiagnostic findings, in-hospital progression, and mechanical ventilation (MV). Patients with VEGBS had higher peak disability (median 5 vs. 4; P = 0.02), frequent in-hospital disease progression (42.9% vs. 19.0%, P < 0.01), needed MV (50% vs. 22.4%; P < 0.01), and less frequent albuminocytologic dissociation (52.4% vs. 74.1%; P = 0.02) than those with early/late GBS. Thirteen patients were lost to follow-up at 6 months (nine patients with VEGBS and four patients with early/late GBS). The proportion of patients with complete recovery at 6 months was comparable (60.6% vs. 77.8%; P = ns ). Reduced d-CMAP was the most common abnormality, noted in 64.7% and 71.6% of patients with VEGBS and early/late GBS, respectively ( P = ns). Prolonged distal motor latency (≥130%) was more common in early/late GBS than in VEGBS (36.2% vs. 25.4%; P = 0.02), whereas absent F-waves were more frequent in VEGBS (37.7% vs. 28.7%; P = 0.03). Patients with VEGBS were more disabled at admission than those with early/late GBS. However, 6 month's outcomes were similar between the groups. F-wave abnormalities were frequent in VEGBS, and distal motor latency prolongation was common in early/late GBS.

Morphological and electrophysiological evaluation of median and ulnar nerve in complex regional pain syndrome type 1.

Complex regional pain syndrome (CRPS) can be distinguished as type I without and type II with electrophysiological evidence of major nerve lesion. The pathophysiology of both subgroups is still under investigation. The aim of this research is to demonstrate the nerve morphology and electrophysiology in CRPS type I patients. Bilateral median and ulnar nerve cross-sectional areas were evaluated with ultrasound and also median and ulnar nerve conduction studies of both hands were performed. Cross-sectional areas of median and ulnar nerves and nerve conduction studies in healthy controls were also obtained and compared with the patients. Twenty-five male patients and 11 healthy male controls were enrolled in the study. The mean age of the patients was 24.08 ± 5.50 years and controls was 23.18 ± 5.09 (p> 0.05). Compound muscle action potential (CMAP) and sensory nerve action potential (SNAP) amplitudes of the diseased side were found significantly lower than the healthy side (p< 0.05). Both median and ulnar nerve distal motor latency values were significantly higher in the patient group (p< 0.05). There was no significant difference in the median and ulnar nerve cross-sectional area when compared with the opposite extremity and healthy volunteers. The lower SNAP and CMAP amplitudes of the median and ulnar nerves compared to the healthy side and the prolongation of the affected side median and ulnar nerve distal motor latencies of the affected individuals may indicate axonal involvement in patients with CRPS type 1. Decreased CMAP amplitudes may also indicate muscle atrophy due to a decrease in the number of functional motor units.

Cranial nerve involvement in patients with immune-mediated neuropathy: An observational blink reflex study

ObjectiveThis study aimed to assess cranial nerve involvement in a large adult cohort of patients with immune-mediated neuropathy undergoing immunoglobulin treatment by measuring blink reflex R1 latency prolongation in correlation with clinical findings and nerve conduction studies. Methods104 patients underwent blink reflex examination and ulnar nerve conduction studies and were assessed by the Inflammatory Neuropathy Cause and Treatment disability score, the revised Amyotrophic lateral sclerosis functional rating scale (ALSFRS-R) and focused clinical examination. ResultsProlonged R1 latencies were identified in 23 of 104 patients (22.1 %). These patients had more severe functional impairments according to the ALSFRS-R, yet only five clinically presented with bulbar dysfunction, facial- or trigeminal nerve impairment. Overall R1 latency was inversely correlated to ulnar motor conduction velocity. In preliminary follow-up assessments under continuous immunoglobulin treatment, prolonged R1 latencies partially improved. ConclusionsCranial nerve involvement is a common feature in immune-mediated neuropathies and is associated with a more severe disease stage. Here, R1 prolongation was detected less frequently compared to previously reported untreated cohorts. SignificanceBlink reflex studies can detect subclinical cranial nerve involvement in immune-mediated neuropathies. Further studies are needed to evaluate the clinical utility of measuring R1 latency.

The sensitivity of median versus ulnar palmar mixed nerve study in the early diagnosis of carpal tunnel syndrome

BackgroundElectrodiagnostic tests (EDX) are the most frequent and applicable studies in early diagnosis of carpal tunnel syndrome (CTS), but the definitive sensitive and specific tests are still under study. We aimed to evaluate the role of the median versus ulnar palmar mixed nerve study (Mix M-U), and its sensitivity in comparison to other provocative comparison studies, in supporting the early diagnosis of CTS. This cross-sectional study included 142 idiopathic early CTS hands from 100 patients and 71 hands from 50 healthy subjects as a control group. We did routine median motor and sensory studies and 4 comparative tests namely median versus radial sensory study (MVR), Mix M-U, median versus ulnar sensory study (MVU), and median versus ulnar lumbrical-interossei motor study (LU-IN).ResultsThe routine median motor and sensory latency and amplitude showed a statistically significant difference between CTS and control groups as (p< 0.05) and a highly statistically significant difference between the 2 groups as regards the 4 comparative tests as (p< 0.0001). The specificities of all the 4 comparative tests were higher than 90%. MVR test had the highest sensitivity (92.2%) and followed by Mix M-U study (82.2%) and MVU (78.7%), and the least sensitive test was the LM-IN (66.9%).ConclusionsAlthough the patients’ results fall within the normal range according to the reference range in the literature, it showed a statistically significant difference when compared to controls. A high percentage of those symptomatic patients showed results of typical CTS when tested with the comparative studies so there is a need to use these sensitive tests to diagnose cases with early CTS. According to sensitivity studies, the selection of which tests to do in order is a challenging choice. For the diagnosis of cases with early CTS with a normal ordinary motor and sensory studies, MVR comparative technique appeared as the best sensitive and specific provocative electrophysiological test followed by the Mix M-U test. We recommend the use of a combination of both tests first in the diagnosis of early CTS and if one of them was negative we can use the other comparative studies MVU and then LM-IN studies.

Reverse End-to-Side Transfer to Ulnar Motor Nerve: Evidence From Preclinical and Clinical Studies.

The disappointing outcomes of conventional nerve repair or grafting procedures for proximal ulnar nerve injuries have led the scientific community to search for better alternatives. The pronator quadratus branch of the anterior interosseous nerve has been transferred to the distal ulnar motor branch in a reverse end-to-side fashion with encouraging results. This transfer is now becoming commonly used as an adjunct to cubital tunnel decompression in patients with compressive ulnar neuropathy, underscoring the need for this knowledge transfer to the neurosurgical community. However, the mechanism of recovery after these transfers is not understood completely. We have reviewed the existing preclinical and clinical literature relevant to this transfer to summarize the current level of understanding of the underlying mechanisms, define the indications for performing this transfer in the clinic, and identify the complications and best practices with respect to the operative technique. We have also attempted to identify the major deficiencies in our current level of understanding of the recovery process to propose directions for future research.