Neurophysiological study to assess the severity of each site through the motor neuron fiber in entrapment neuropathy

The purpose of this study is to evaluate prospectively the sensitivities of conventional and new electrophysiological techniques and to investigate their relationship with the body mass index (BMI) in a population of patients suspected of having carpal tunnel syndrome (CTS). In this study, 165 hands of 92 consecutive patients (81 female, 11 male) with clinical diagnosis of CTS were compared to reference population of 60 hands of 30 healthy subjects (26 female and 4 male). Extensive sensory and motor nerve conduction studies (NCSs) were performed in the diagnosis of subtle CTS patients. Also, the patients were divided into subgroups and sensitivities were determined according to BMI. The mean BMI was found to be significantly higher in the CTS than in the control group (p < 0.001). The sensitivity of the median sensory nerve latency (mSDL) and median motor distal latency (mMDL) were 75.8% and 68.5%, respectively. The most sensitive parameters of sensory and motor NCSs were the difference between median and ulnar sensory distal latencies to the fourth digit [(D4M-D4U), (77%)] and the median motor terminal latency index [(mTLI), (70.3%)], while the median-to-ulnar sensory action potential amplitude ratio (27%) and the median-thenar to ulnar-hypothenar motor action potential amplitude ratio (15%) were least sensitive tests. Sensory tests were more sensitive than motor NCSs. Combining mSDL with D4M-D4U, and mMDL with mTLI allowed for the detection of abnormalities in 150 (91%) and 132 (80%) hands, respectively. Measurements of all NCSs parameters were abnormal in obese than in non-obese patients when compared to the BMI. The newer nerve conduction techniques and combining different NCSs tests are more sensitive than single conventional NCS test for the diagnosis of suspected CTS. Meanwhile, CTS is associated with increasing BMI.     

Carpal Tunnel Syndrome Assessment with Ultrasonography: Value of Inlet-to-Outlet Median Nerve Area Ratio in Patients versus Healthy Volunteers

Objective

To evaluate the diagnostic value of the Inlet-to-outlet median nerve area ratio (IOR) in patients with clinically and electrophysiologically confirmed carpal tunnel syndrome (CTS).

Methods

Forty-six wrists in 46 consecutive patients with clinical and electrodiagnostic evidence of CTS and forty-four wrists in 44 healthy volunteers were examined with ultrasonography. The cross-sectional area (CSA) of the median nerve was measured at the carpal tunnel inlet (the level of scaphoid-pisiform) and outlet (the level of the hook of the hamate), and the IOR was calculated for each wrist. Ultrasonography and electrodiagnostic tests were performed under blinded conditions. Electrodiagnostic testing combined with clinical symptoms were considered to be the gold standard test. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic value between the inlet CSA and IOR.

Results

The study population included 16 men and 30 women (mean age, 45.3 years; range, 18–83 years). The control population included 18 men and 26 women (mean age, 50.4 years; range, 18–79 years). The mean inlet CSA was 8.7 mm² in healthy controls and 14.6mm² in CTS group (P<0.001). The mean IOR in healthy volunteers (1.0) was smaller than that in patients (1.6, P<0.001). Receiver operating characteristic analysis revealed a diagnostic advantage to using the IOR rather than the inlet CSA (P<0.01). An IOR cutoff value of ≥ 1.3 would yield 93% specificity and 91% sensitivity in the diagnosis of CTS.

Conclusion

The IOR of median nerve area promises to be an effective means in the diagnosis of CTS. A large-scale, randomized controlled trial is required to determine how and when this parameter will be used.     

Comparison of clinical findings and electromyography results in patients with preliminary diagnosis of carpal tunnel syndrome

ObjectiveTo evaluate the link between EMG findings and clinical status, the Boston questionnaire and the severity of pain in patients with pre-diagnosis of carpal tunnel syndrome.MethodsA total of 85 patients (133 hands) who presented to the Physical Therapy and Rehabilitation outpatient clinic consecutively with complaints of numbness, tingling, pain and weakness in their hands were evaluated for their demographic and clinical features. After the initial evaluation, the diagnosis of CTS was confirmed by EMG. Visual analog scale (VAS), the Boston Questionnaire (Symptom Severity Scale = SSS, Functional Status Scale = FSS) and nerve conduction study results (sensory conduction velocity = SCV, distal motor latency = DML, compound muscle action potential = CMAP) were enrolled.ResultsEighty-five patients (58 female and 27 male) participated in this study yielding 133 hands (73 right hands, 60 right hands) with CTS. The mean age was 48.3 ± 10.41 years. Of all patients, 68.2 % were female and 31.8 % were male. A statistically significant relationship was found between SSS and duration of symptoms, VAS, both right and left SCV, DML and CMAP. A statistically significant relationship was found between FSS and duration of symptoms, VAS and only right SCV, DML and CMAP.ConclusionThe diagnosis of CTS should be evaluated not only as an electrodiagnostic finding, but also the clinical picture of the patients. According to our results, both SSS and FSS had good correlations with VAS and the findings of EMG. Therefore, the Boston Questionnaire can provide a standardized measure of symptom severity and functional status in patients with CTS.     

The effect of provocative tests on electrodiagnosis criteria in clinical carpal tunnel syndrome

Introduction and objectiveNerve conduction study is the most sensitive test for diagnosis of carpal tunnel syndrome (CTS). This test is normal in some patients with mild CTS. Median nerve conduction study evaluation after a provocative test (e.g. wrist flexion) may be helpful for diagnosis of mild CTS. This study aimed to determine the effect of wrist flexion on median nerve conduction in patients suspected to CTS and in healthy subjects.Materials and methodsIn this case-control study, 20 patients (20 hands) with clinical signs of CTS and normal routine electrodiagnosis test results and 20 healthy subjects were investigated. Measured parameters included: median nerve distal sensory latency (DSL), nerve conduction velocity (NCV) across wrist, compound nerve action potential (CNAP), distal motor latency (DML) and compound muscle action potential amplitude (CAMPAMP). The above noted parameters were measured before and after 5 min of full wrist flexion. Data were analyzed using paired T-test.ResultsDistal sensory latency increment and NCV decrimental after 5 min of wrist flexion in the patients group were statistically significant (p < 0.01). The same parameters did not show significant incremental or detrimental changes in the control group.ConclusionMedian nerve DSL and NCV measurement after 5 min of wrist flexion may be helpful in determining more sensitive parameters in the electrodiagnosis of CTS.     

肌电图检查评估腕管综合征手术效果的临床分析

目的:探讨采用肌电图检查评估腕管综合征的手术治疗效果。方法:选取35例(患侧手共39侧)临床确诊为腕管综合征并接受腕管切开减压术治疗的患者,于手术前后分别行肌电图检查,应用正中神经传导检查和拇短展肌针极肌电图检查,分析患者手术前和手术后腕部正中神经功能的变化情况。结果:手术后,患者正中神经感觉传导潜伏期异常率(33%)、正中神经运动传导潜伏期异常率(36%)较手术前(72%、74%)明显下降(P0.05),正中神经感觉传导波幅(7.40±5.05)较手术前(4.86±3.60)显著降低(P0.001),拇短展肌静息状态下失神经电位的异常率(69%)、重收缩时募集电位异常率(13%)均较手术前(85%、26%)明显下降(P0.05)。患者手术前后正中神经感觉传导速度和运动传导速度对比差异无统计学意义(P0.05)。结论:腕管切开减压术可解除正中神经卡压状态,明显恢复正中神经功能,增强拇短展肌肌力,临床治疗效果好。肌电图检查可为腕管综合征患者手术治疗效果的评估提供客观的依据。     

Physiologic changes of compound muscle action potentials related to voluntary contraction and muscle length in carpal tunnel syndrome.

The affect of muscle length and voluntary contraction upon compound muscle action potentials (CMAPs) in subjects with carpal tunnel syndrome (CTS) has been evaluated. Twenty-five hands in a CTS patient group and 29 hands in a normal subject control group were studied. The CMAPs from the abductor pollicis brevis induced by median nerve stimulation at the wrist were obtained for five thumb positions: neutral, abduction for shortening with and without contraction, and adduction for lengthening with and without contraction. Upon muscle shortening with relaxation, CMAP duration decreased in both groups, whereas waveform amplitude increased in the control group and showed no significant change in the CTS group. Muscle shortening with contraction afforded decreased CMAP duration and increased CMAP amplitude in both groups. Upon muscle lengthening with relaxation, both groups showed a reduction in CMAP amplitude and an increase in CMAP duration. Upon lengthening with contraction, CMAP duration decreased in the control group; in contrast, the CTS group showed further amplitude reduction and the waveform duration returned to the neutral value. These results demonstrate that, in patients with CTS, physiologic CMAP summations by muscle shortening or contraction may be less effective, whereas decreases in amplitude and increases in duration may be accentuated by lengthening and contraction.     

Finite element simulation of the mechanical impact of computer work on the carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is a clinical disorder resulting from the compression of the median nerve. The available evidence regarding the association between computer use and CTS is controversial. There is some evidence that computer mouse or keyboard work, or both are associated with the development of CTS. Despite the availability of pressure measurements in the carpal tunnel during computer work (exposure to keyboard or mouse) there are no available data to support a direct effect of the increased intracarpal canal pressure on the median nerve.     

Test of a new technique for the diagnosis of carpal tunnel syndrome.

Several new techniques for carpal tunnel syndrome diagnosis have been developed in the last few years. This work tests a technique that compares the distal motor latency of the median nerve to the second lumbrical muscle (2L) with the distal motor latency of the ulnar nerve to the interossei muscle (INT). Results from 40 normal hands give the superior limit of the normal difference (2L-INT) as 0. 26 ms (&xmacr;+3 SD). In 55 hands with different levels of carpal tunnel syndrome, this new technique was more sensitive and accurate than the conventional test which uses the distal motor latency of the median nerve to the abductor pollicis brevis muscle (APB), especially in the less severe cases. With the absence of the compound muscle action potentials of the APB muscle caused by severe thenar atrophy, it is much easier to obtain the potential from the 2L muscle. We concluded that this is a sensitive, simple, rapid, and non-invasive new technique, and therefore, it should be incorporated as part of the routine ENMG procedures for carpal tunnel syndrome diagnosis.     

Compression neuropathy from muscle fibrosis induced by repeated meperidine injections

The combination of myopathy and neuropathy with fibrosis and contractures has apparently not yet been reported from the use of meperidine. We describe a patient addicted to meperidine in whom bilateral hand numbness and weakness developed and electrodiagnostic studies revealed moderate slowing of motor nerve conduction velocities. Neurolysis of the median and ulnar nerves resulted in markedly improved symptoms.     

A fluid-immersed multi-body contact finite element formulation for median nerve stress in the carpal tunnel

Carpal tunnel syndrome (CTS) is among the most important of the family of musculoskeletal disorders caused by chronic peripheral nerve compression. Despite the large body of research in many disciplinary areas aimed at reducing CTS incidence and/or severity, means for objective characterization of the biomechanical insult directly responsible for the disorder have received little attention. In this research, anatomical image-based human carpal tunnel finite element (FE) models were constructed to enable study of median nerve mechanical insult. The formulation included large-deformation multi-body contact between the nerve, the nine digital flexor tendons, and the carpal tunnel boundary. These contact engagements were addressed simultaneously with nerve and tendon fluid-structural interaction (FSI) with the synovial fluid within the carpal tunnel. The effects of pertinent physical parameters on median nerve stress were explored. The results suggest that median nerve stresses due to direct structural contact are typically far higher than those from fluid pressure.     

Assessment of Median Nerve Mobility by Ultrasound Dynamic Imaging for Diagnosing Carpal Tunnel Syndrome

Carpal tunnel syndrome (CTS) is the most common peripheral neuropathy and is characterized by median nerve entrapment at the wrist and the resulting median nerve dysfunction. CTS is diagnosed clinically as the gold standard and confirmed with nerve conduction studies (NCS). Complementing NCS, ultrasound imaging could provide additional anatomical information on pathological and motion changes of the median nerve. The purpose of this study was to estimate the transverse sliding patterns of the median nerve during finger movements by analyzing ultrasound dynamic images to distinguish between normal subjects and CTS patients. Transverse ultrasound images were acquired, and a speckle-tracking algorithm was used to determine the lateral displacements of the median nerve in radial-ulnar plane in B-mode images utilizing the multilevel block-sum pyramid algorithm and averaging. All of the averaged lateral displacements at separate acquisition times within a single flexion–extension cycle were accumulated to obtain the cumulative lateral displacements, which were curve-fitted with a second-order polynomial function. The fitted curve was regarded as the transverse sliding pattern of the median nerve. The R² value, curvature, and amplitude of the fitted curves were computed to evaluate the goodness, variation and maximum value of the fit, respectively. Box plots, the receiver operating characteristic (ROC) curve, and a fuzzy c-means clustering algorithm were utilized for statistical analysis. The transverse sliding of the median nerve during finger movements was greater and had a steeper fitted curve in the normal subjects than in the patients with mild or severe CTS. The temporal changes in transverse sliding of the median nerve within the carpal tunnel were found to be correlated with the presence of CTS and its severity. The representative transverse sliding patterns of the median nerve during finger movements were demonstrated to be useful for quantitatively estimating median nerve dysfunction in CTS patients.     

A regression model for carpal tunnel syndrome

The purpose of this study was to determine whether a logistic regression model for the diagnosis of carpal tunnel syndrome (CTS) could be developed. Forty-eight variables were initially identified, for the 28 CTS and 34 non-CTS subjects, including 28 measures of nerve function, 6 anatomical measurements, 8 variables relating to disease symptoms, and 6 variables relating to physical attributes. An a priori clustering procedure was used to establish groups for the principal components analyses. The first principal component of each cluster was then used in a backward, stepwise logistic regression analysis. The best combination of candidate variables, as identified by the regression equation, was Raynaud's symptoms and median nerve motor function. The results of this study indicate that a model for CTS can be generated from a set of variables and that a linear combination of variables representing nerve function is closely associated with conduction decrements resulting from CTS.     

Anatomic observations of the carpal tunnel in cadavers with a report of unusual thickening of the perineurium of the median nerve

The carpal tunnel of 50 cadavers (100 hands) was dissected. Macroscopic finding included 14 median nerves with pressure signs (in 4 cadavers, unilaterally and 5 bilaterally). In three cadavers, marked synovitis was seen around the tendons and the nerve; in one, lipoma was evident; and in the rest, thickening of the volar carpal ligament was seen. Microscopic examination of the compressed nerves showed concentric thickening of the perineurium, thrombosis of veins, and intrafascicular fibrosis. In one nerve, the thickening of the perineurium was not concentric, but only at that part of the fascicle adjacent to the volar carpal ligament in an "onion peel" form.     

Org.2766 improves functional and electrophysiological aspects of regenerating sciatic nerve in the rat

The beneficial effect of short-term (8 days) melanocortin therapy on regenerating peripheral nerves is demonstrated using functional and electrophysiological tests. Following a crush lesion of the rat sciatic nerve, recovery of sensory function is monitored by assessing the responsiveness of the rat to a small electric current applied to the footsole. Recovery of motor function is assessed by means of an analysis of walking patterns. Normalization of the walking pattern reflects reinnervation of different muscle groups. The motor and H-reflex related sensory nerve conduction velocity of the regenerated nerves are longitudinally investigated in the same rats in which the recovery of motor and sensory function had been assessed previously. Functional tests show an enhanced recovery under melanocortin therapy, but in the end both saline- and melanocortin-treated rats show 100% recovery. However, when compared to the contralateral sciatic nerve, in the peptide-treated animals motor nerve conduction in the regenerated nerves has fully recovered after about 90 days following the crush lesion and the sensory conduction after about 120 days, whereas in the saline-treated rats a deficit of 20-40% in both motor and sensory conduction remains. This difference is observed even 214 days following crush.     

An Electrophysiological Study of Acute Tetrodotoxin Poisoning

To evaluate the electrophysiological changes in patients with acute tetrodotoxin (TTX) poisoning from ingestion of globefish (Tetraodontidae) patients exposed to TTX were compared with age-matched controls. The cohort of TTX-poisoning cases was clinically subdivided into mild, moderate, or severe cases. The motor nerve conduction velocity (MCV), sensory nerve conduction velocity (SCV), F-wave, H-reflex, and somatosensory-evoked potentials (SEP) of the median, ulnar, and common peroneal nerve (CPN) were determined using established techniques. Four of the 64 (6.3%) TTX-poisoning cases died and were omitted from the final analysis. The MCV and SCV of the median, ulnar, and CPN nerves in all the TTX-poisoning cases were significantly slower than the healthy controls. Severe cases of TTX poisoning had more significant reduction in nerve function. Thus, electroneurophysiological analysis could be used to determine the extent, course, and range of nerve system damage in patients with acute TTX poisoning.     

Concomitant presentation of carpal tunnel syndrome and trigger finger

Background

Carpal tunnel syndrome (CTS) and trigger finger (TF) are common conditions that may occur in the same patient. The etiology of most cases is unknown. The purpose of this study was to evaluate the rate of concomitant occurrence of these two conditions at presentation and to compare the concomitant occurrence in normal and diabetic patients.

Methods

One-hundred and eight consecutive subjects presenting to our hand clinic with CTS and/or TF were evaluated. The existence of both of these conditions was documented through a standard history and physical examination. The definition of trigger finger was determined by tenderness over the A1 pulley, catching, clicking or locking. CTS was defined in the presence of at least two of the following: numbness and tingling in a median nerve distribution, motor and sensory nerve loss (median nerve), a positive Tinel's or Phalen's test and positive electrophysiologic studies.

Results

The average age of the participants was 62.2 ± 13.6 years. Sixty-seven patients presented with symptoms and signs of CTS (62%), 41 (38%) subjects with signs and symptoms of TF. Following further evaluation, 66 patients (61%) had evidence of concomitant CTS and TF. Fifty-seven patients (53% of all study patients) had diabetes. The rate of subjects with diabetes was similar among the groups (p = 0.8, Chi-square test).

Conclusion

CTS and TF commonly occur together at presentation though the symptoms of one condition will be more prominent. Our results support a common local mechanism that may be unrelated to the presence of diabetes. We recommend evaluation for both conditions at the time of presentation.     

The Carpal Tunnel Syndrome—A Review of 100 Patients Treated Surgically

The carpal tunnel syndrome, or compression neuropathy of the median nerve at the wrist, is a common cause of burning pain, numbness and tingling in the hand. The diagnosis is suggested by nocturnal paresthesias in the thumb, index and long fingers associated with signs of irritability of the median nerve in the carpal tunnel at the wrist. Surgical treatment in the form of incision of the transverse carpal ligament should be performed before irreversible motor and sensory changes occur.     

Interaction Effects of Wrist and Forearm Posture on the Prediction of Carpal Tunnel Syndrome Cases Within a Fish-Processing Facility

Deviated wrist posture has been implicated as a risk factor for carpal tunnel syndrome (CTS), although alone it has not been found to have a causal relationship with CTS. Studies investigating deviated wrist posture have quantified posture in a single plane of motion and not interactions of wrist postures in multiple planes. The objective of this cross-sectional study was to investigate the ability of wrist and forearm posture interaction effects to predict CTS among a population of fish processing operators. A total of 53 participants performing five job tasks were evaluated using electrogoniometers. Due to task asymmetry, each hand was evaluated separately and treated independently, providing 106 hands as data observations. Using logistic regression analysis it was found that a model including flexed (F); extended (E), the interaction of length of employment (LE) by FE, and the interaction of LE by FE by pronation/supination (PS) accurately classified 78% of all hands as cases or non-cases. The sensitivity of the final model was approximately 48%. The developed model was found to have superior predictive ability when compared to models not considering interaction terms, indicating that posture interactions may in fact have a significant effect on CTS alone.     

Estrogen and progesterone receptors in carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is a compression median nerve neuropathy common in women at menopausal age. The aim of this work was to study immunohistochemically the expression of estrogen (ER) and progesterone (PR) receptors in CTS and control specimens. Biopsies of transverse carpal ligament (TCL) and flexor tendon synovitis were collected from 23 women and from 7 men undergoing surgery for median nerve decompression at the wrist for CTS. In TCL and synovial tissue, cells expressed ER and PR with statistically significant differences related to the age and sex of patients. Immunoreactivity was observed in fibroblasts of TCL, and in lining cells and fibroblasts of synovial tissue. In women, the number of ER-positive cells in the TCL and synovial tissue increased with the age, peaking at 55-70 years, and then decreasing. PR-immunoreactivity was observed only in fibroblasts of TCL and its expression decreased with age, while no immunolabeling was found in the synovial tissue. In TCL samples, the number of ER- and PR-positive cells in non-CTS patients was significantly lower than in CTS patients. These results demonstrate that ER and PR are present in TCL and flexor tendon synovitis, suggesting a role for sex steroid hormones in the pathogenesis of CTS disease.     

Central representation and functional connections of afferent and efferent pathways of Helix pomatia L. lip nerves

Localization and distribution of cerebral neurones sending axons into the three pairs of Helix pomatia lip nerves were investigated by the method of retrograde axonal NiCl2 transport. Using electrophysiological technics (extracellular recordings) the dependence of lip nerve's activity on inputs of other lip nerves was studied after application of various types of stimuli to the lip of semi-intact preparations. All lip nerves have neuronal representation in each lobe of the cerebral ganglia but in different proportions. Labelled neurones were located mainly on the ventral surface of the cerebral ganglia, most of them projecting to the medial, the least to the inner lip nerve. Lip nerves differ from each other according to the proportions of neurones of various size. They share in the axons of large (55-70 microns) and medium sized (30-40 microns) neurones in the order inner greater than outer greater than medial and medial greater than outer greater than inner lip nerve, respectively. Most neurones projecting to different nerves are located in discrete groups. According to the electrophysiological results the medial lip nerve has the most prominent afferent, while the inner one has the strongest efferent activity. Both the afferent and efferent activities of the outer lip nerve proved to be the least significant compared to the other lip nerves. Contralateral cerebral connections play an important role in the sensory information processing. The sensory input of a given nerve usually activates the contralateral member of another pair of lip nerves. Mechano- and chemo-afferent pathways have almost the same properties but there are some differences in latencies and other parameters.