Stage Of Carpal Tunnel Syndrome Research Articles

Prolonged median distal sensory nerve action potential duration in carpal tunnel syndrome.

Routine nerve conduction study (NCS) parameters are less sensitive in the early stage of carpal tunnel syndrome (CTS). Recently, some studies have shown that prolonged distal sensory nerve action potential (DSNAP) duration may be a more sensitive technique for the diagnosis of demyelinating peripheral neuropathies. We aimed to evaluate the sensitivity of median DSNAP duration in patients with CTS. DSNAP duration and routine NCS data of the median nerve were retrospectively collected in 173 CTS patients, 73 controls, and 78 cervical radiculopathy patients. Prolonged median DSNAP durations were found in 22 patients (22/35, 63%) and 36 patients (36/54, 67%) in the minimal and mild CTS groups respectively, which was more sensitive than routine NCS parameters. The percentage of patients demonstrating abnormalities in median NCS was significantly increased from 80% to 92% with the addition of DSNAP duration. Our results demonstrate the electrodiagnostic value of median DSNAP duration for the diagnosis of CTS, especially in early cases.

Application of shear wave elastography and median nerve cross-section area in the diagnosis and staging of carpal tunnel syndrome: a case-control study

PurposeImaging is gaining a more prominent role in the diagnosis of carpal tunnel syndrome (CTS), especially ultrasonography. Shear wave elastography (SWE) is a novel qualitative method to study mechanical changes in tissue. In this study, we aim to assess the role of SWE in diagnosing and staining of the disease.Material and methodsA total of 124 wrists were included in the study. Seventy wrists had CTS, and 54 were included as the control group. All of the wrists with CTS had staging done with nerve conduction study. All patients underwent ultrasonography by an expert radiologist and had the SWE and cross-section of the median nerve determined. These values were compared among the 2 groups and different stages of CTS. The receiver operating characteristic curve was utilized to assess the diagnostic role of each of the variables.ResultsCross-section area (CSA) and SWE were significantly different between the 2 groups (p = 0.0001). CSA was also significantly different among various stages of CTS. SWE was not significantly different among moderate and severe stages of CTS. Both of the variables had a good ability to distinguish mild CTS from healthy wrists (p = 0.0001).ConclusionSWE can be used in diagnosing CTS and in the staging of the disease.

Relationship of Vitamin D Level, Fasting Blood Sugar, and Body Mass Index, to Carpal Tunnel Syndrome Severity

Aim: This study aims to investigate the relationship between Idiopathic Carpal Tunnel Syndrome (CTS) and Vitamin D Level, Body Mass Index (BMI), and Fasting Blood Sugar.Materials and Methods: 54 CTS patients diagnosed electrophysiologically were included in the study. These patients' ages, genders, height and body weights, and body mass index values were recorded. Laboratory tests including vitamin D levels and fasting blood sugars were performed for each participant. The CTS stage was determined electrophysiologically and the Boston questionnaire and the visual analogue scale (VAS) were filled to assess total pain scores, symptom severities (CNS), and functional states (FSS).Results: There was a statistically significant difference between the distribution of CTS stages in female patients and male patients (p = 0.008). There was no statistically significant difference between mild, moderate, and severe CTS stages in terms of age, body mass index, and fasting blood glucose (p = 0.459; p = 0.232; p = 0.413, respectively). There is a statistically significant difference between CTS stages in terms of vitamin D levels (p0.001). Vitamin D averages were observed to decline from mild to severe stages of CTS. According to the Boston Carpal Tunnel Syndrome functional status scale, it was determined that there is marginal statistical significance between the stages of CTS. It was observed that the mean functional status scale scores increased from the mild stage to the severe stage (p = 0.055). There was no statistically significant difference between mild, moderate, and severe CTS stages in terms of VAS pain and paresthesia scores and the Boston Carpal Tunnel Syndrome symptom severity scale (p = 0.340; p = 0.359; p = 0.250, respectively).Conclusion: We found a significant relationship between the vitamin D level and the CTS stage. According to Boston Carpal Tunnel Syndrome Questionnaire, we found that there is a marginal statistical significance between the stages of CTS.

Alpha-Lipoic Acid Effectiveness in Early Stages of Carpal Tunnel Syndrome: Short Term Follow-up

Alpha-Lipoic Acid Effectiveness in Early Stages of Carpal Tunnel Syndrome: Short Term Follow-up

Evaluation of Duruöz Hand Index in diagnosis and staging of Carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is a common entrapment neuropathy of the upper limb. In this cross-sectional study our aim is to investigate the value of Duruöz Hand Index (DHI) in diagnosis and staging of CTS patients and comparing it with Boston Carpal Tunnel Questionnaire (BQ) and provocative tests. Among 423 patients who were referred to the EMG laboratory at the physical medicine and rehabilitation unit with the symptoms of CTS, 294 patients were included in the study. Patients’ demographic data, weight, height, body mass index (BMI) measurements, physical examinations, Tinel and Phalen provocative test results, visual analog scale for pain, DHI and BQ scores were recorded. Electrophysiological examinations were also performed. The mean age was 45.1 ± 11.6 years and 254 (86.4%) patients were women. Based on the results of EMG, 120 (40.8%) patients were found negative for CTS, 57 (19.4%) patients had mild CTS, 89 (30.3%) patients had moderate CTS and 28 (9.5%) patients had severe CTS. Among the parameters evaluated, DHI scores were found to be significantly higher in the severe CTS group. DHI (r: 0.306, p < 0.001) and Boston functional status scale (FSS) (r: 0.257p = 0.001) were found to be correlated with CTS severity. Tinel positivity (OR: 2.36, p: 0.01), Phalen positivity (OR: 2.22, p: 0.02), Boston symptom severity scale (SSS) scores (OR: 1.76, p: 0.024), increasing age (OR: 1.06, p < 0.001) and increased BMI (OR: 1.07, p: 0.03) were found to be associated with increased likelihood of CTS diagnosis. In conclusion, DHI was found to be correlated with CTS severity similar to Boston FSS.

An advanced stage of carpal tunnel syndrome - is night-time splinting still effective?

There is no consensus on whether conservative treatment with night splints is indicated also in moderate and severe stages of carpal tunnel syndrome (CTS). The goal of this study was to compare the efficacy of night-time splinting at different stages of CTS. Forty-five patients with electrodiagnostic (EDX) features of CTS included in the study were divided into 2 groups based on nerve conduction studies. The patients in the first group had only median nerve sensory fiber involvement, whereas the patients in the second group had also motor fiber involvement. The custom-made volar night splint was the only treatment for all of the included patients. The patients were assessed before the fabrication of orthosis and after 12 weeks of its use. The parameters measured were hand grip strength and the Visual Analogue Scale for pain and paraesthesia. The patients further completed the Boston Carpal Tunnel Syndrome Questionnaire (BCTQ) and a shorter version of the Disabilities of the Arm, Shoulder and Hand Questionnaire (QuickDASH). In the first group, a statistically significant improvement was established in paraesthesia and hand grip strength (p = 0.019, p = 0.024, respectively), but there was no statistically significant improvement in pain, and the results of both BCTQ and QuickDASH. In the second group, a statistically significant improvement was found in paraesthesia, the BCTQ Symptom Severity Scale and QuickDASH results (p = 0.008, p < 0.001, p = 0.011, respectively), whereas no statistically significant improvement was established in pain, hand grip strength and the BCTQ Functional Status Scale. However, when comparing the change in the outcome measures between the 2 groups, no statistically significant differences were found. This study has shown that 12-week night-time splinting is beneficial not only for patients with mild CTS but also for those with advanced CTS, and those awaiting surgical treatment. Therefore, splinting is recommended for all patients with CTS. Int J Occup Med Environ Health. 2020;33(6):771-80.

Carpal Tunnel Syndrome: A Review of Literature.

Carpal tunnel syndrome (CTS) is a common medical condition that remains one of the most frequently reported forms of median nerve compression. CTS occurs when the median nerve is squeezed or compressed as it travels through the wrist. The syndrome is characterized by pain in the hand, numbness, and tingling in the distribution of the median nerve. Risk factors for CTS include obesity, monotonous wrist activity, pregnancy, genetic heredity, and rheumatoid inflammation. The diagnosis of CTS is conducted through medical assessments and electrophysiological testing, although idiopathic CTS is the most typical method of diagnosis for patients suffering from these symptoms. The pathophysiology of CTS involves a combination of mechanical trauma, increased pressure, and ischemic damage to the median nerve within the carpal tunnel. The diagnosis of CTS patients requires the respective medical professional to develop a case history associated with the characteristic signs of CTS. In addition, the doctor may question whether the patients use vibratory objects for their tasks, the parts of the arm where the sensations are felt, or if the patient may already have predisposing factors for CTS incidence. During the diagnosis of CTS, it is essential to note that other conditions may also provide similar symptoms to CTS, thus requiring vigorous diagnosis to assert the medical condition of the patients. Doctors use both non-surgical and surgical treatments when addressing CTS. Non-surgical treatments include wrist splinting, change of working position, medications, and the use of alternative non-vibrating equipment at work. On the other hand, surgical methods include open release and endoscopic surgeries. This review of literature has provided an overview of CTS with an emphasis on anatomy, epidemiology, risk factors, pathophysiology, stages of CTS, diagnosis, and management options.

The usefulness of ultrasonography to diagnose the early stage of carpal tunnel syndrome in proximal to the carpal tunnel inlet

This study aimed to investigate the relationship between the change of median nerve cross-sectional area (CSA) and the severity of carpal tunnel syndrome (CTS) determined by electrodiagnostic study based on the area immediately proximal to the carpal tunnel inlet (IPCTI).From December 2016 to August 2017, 34 patients (8 men and 26 women; mean age, 61.68 years ± 11.83; range, 28–80 years) with CTS symptoms were recruited. Electrodiagnostic study was performed in all patients to categorize the severity of CTS according to Bland classification. The CSA of median nerve and carpal tunnel at IPCTI, and carpal tunnel inlet/outlet level was measured by one physician. The Kruskal-Wallis test was used for comparing the CSA of the median nerve and carpal tunnel among CTS severity groups divided by electrodiagnostic study. The Dunn procedure was used for post-hoc comparison.At IPCTI and the carpal tunnel inlet level, the CSA of the median nerve was statistically larger depending on the severity of CTS (P < .01, P < .01). In the post-hoc comparison, only the CSA measured at the IPCTI level could differentiate normal reference values from mild CTS indicating the early stage (P < .05).Measuring the CSA of median nerve in IPCTI level is the most sensitive method to diagnose the early stage CTS.

P58-T Electrophysiological assessment of small fibres in carpal tunnel syndrome

Background Conventional nerve conduction techniques have limitations on carpal tunnel syndrome (CTS) diagnosing, because dysfunction of small fibres is beyond the resolution of these studies. The lack of the gold standard of CTS evaluation and common misdiagnosis underlie the treatment failure. Evaluation of small fibres susceptibility to damage and the sequence of decline of different types of fibres in CTS were analyzed. Materials and methods 75 hands, in 43 patients, 35 females, 8 males, with elecrophysiologically confirmed CTS were studied. The control group consisted of 35 volunteers (63 hands), sex and age-matched. Standard motor and antidromic sensory nerve conduction velocity studies in the median and ulnar nerves, with distal onset latency, conduction velocity, and amplitude assessment were done. Conduction velocity distribution test (CVD) was performed in the same nerves with estimation of conduction velocities in 10, 50, 90 decyl, and the conduction spread between 90 and 10 decyl. Quantitative sensory testing (QST) for detection temperature, pain and vibratory theresholds were done from thenar and hypothenar skin. Results CVD values of the median nerve in all decyls differed significantly between the carpal tunnel syndrome group and the control group, without any significant differences in the spread of conduction values. The thresholds of temperature and pain were similar, but the vibratory thresholds were significantly higher in the CTS group. Conclusions Mainly large fibers of the median nerve are damaged in the initial stage of CTS. Evaluation of small fibers is not useful in the early diagnosis of CTS.

Quantitative evaluation of hand motor function using a gyrosensor in mild and moderate carpal tunnel syndrome.

The objective of this study was to determine whether patients with carpal tunnel syndrome (CTS) manifest changes in early-stage motor function and to investigate the utility of a gyrosensor for quantitative evaluation of motor function. Angular velocity signal was measured during finger tapping in 52 patients with mild-to-moderate CTS and 45 controls. Four finger-tapping performance (FTP) values-root-mean-squared (RMS) velocity, RMS angle, peak power, and total power-were derived from the signal. All FTP values were significantly lower in patients with CTS than in controls (P = 0.001 or P < 0.001). There were no significant differences between the mild and moderate CTS subgroups. FTP measurement with a gyrosensor represents a valuable tool for the evaluation of median nerve motor function in patients with CTS. It facilitates the detection of subclinical motor dysfunction in patients with early stage CTS. Muscle Nerve 59:465-469, 2019.

The efficiency of acoustic radiation force impulse (ARFI) elastography in the diagnosis and staging of carpal tunnel syndrome.

The aim of the present study was to quantify the stiffness of the median nerve (MN) at the carpal tunnel inlet by acoustic radiation force impulse (ARFI) elastography and to evaluate whether ARFI can be used in diagnosis and staging of carpal tunnel syndrome (CTS). Sonographic examinations of 96 wrists in 50 patients were included in the study. The cross-sectional area and stiffness of the MN were quantitatively measured by B-mode ultrasonography (USG) and ARFI. The findings of CTS were assigned to four groups: (I) normal (n=21), (II) mild (n=39), (III) moderate (n=38), and (IV) severe (n=19). The differences between CTS patients and controls and the differences in electrodiagnostic tests among subgroups were statistically compared. ROC analysis was performed to determine the cut-off values between subgroups. Bilateral CTS was present in 46 patients (92 wrists) and unilateral CTS in four patients. Of the 96 nerves in the 50 symptomatic "idiopathic CTS" patients (48 women, 2 men; mean age 45.9years, range 23-73years), 39 (40.4%) were mild, 38 (39.8%) were moderate, and 19 (19.8%) were severely affected. When compared to controls, MN stiffness was significantly higher in the CTS group (P<0.001); furthermore, it was higher in the severe or extreme severity group than the mild or moderate severity group (P<0.001). A 3.250m/s cut-off value on ARFI revealed sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 81, 82, 95.1, 50, and 82%, respectively. The MN stiffness measured by ARFI elastography is significantly higher in patients with CTS then in controls. ARFI elastography appears to be a highly efficient imaging modality for the diagnosis and staging of these patients.

Ultrasonography of the Transverse Movement and Deformation of the Median Nerve and Its Relationships With Electrophysiological Severity in the Early Stages of Carpal Tunnel Syndrome

BackgroundTo date, there have been conflicting suggestions regarding the initial pathogenesis of carpal tunnel syndrome (CTS). It has been characterized as either inflammation of the median nerve caused by compression or noninflammatory fibrosis of the subsynovial connective tissue (SSCT). ObjectiveTo investigate the initial pathogenesis of CTS, we compared the deformation and displacement of the median nerve in accordance with the electrophysiological severity between patients with CTS (via the Bland scale) and healthy controls. DesignCross-sectional, case-control study. SettingGeneral teaching hospital, rehabilitation unit. PatientsThirteen hands of 10 healthy participants and 39 hands of 27 patients with CTS were recruited and classified into 4 groups (stage 0−3) according to the severity of the electrodiagnostic test results. MethodsUltrasound images of the median nerve in response to the wrist and finger motions were analyzed. Main Outcome MeasureWe measured the deformation of the median nerve (the maximal change values of the median nerve area, and aspect ratio of the minimum-enclosing rectangle [MER]) and movement of the median nerve (the maximal change value of the median nerve displacement) in response to the motions of wrists and finger. The maximal change value of the median nerve displacement was normalized with respect to the width of the wrist. Moreover, the maximal change values of the median nerve area, and the aspect ratio of the MER, were also normalized to the median nerve area and the aspect ratio of the MER in wrist-neutral position with finger extension. ResultCTS patients in stage 3 showed a significantly lower normalized maximal change of the median nerve movement compared with CTS patients in stages 0, 1, and 2 (P <.001). Regarding the deformation of the median nerve, however, there were statistically significant differences among all groups (area, P < .001; MER, P <.001). According to multivariate logistic regression analysis, the normalized maximal change of the aspect ratio of the MER is a meaningful parameter in diagnosing the initial stage of CTS (P < .01). ConclusionThese results showed that the deformation of the median nerve may be associated with the initial pathogenesis; however, further studies are necessary to validate the findings of this study. Level of EvidenceIII

Hypothenar fat pad flap surgery for end stage and recurrent carpal tunnel syndrome

One year follow-up results after hypothenar fat pad flap surgery for recurrent and end stage carpal tunnel syndrome (CTS) are reported. Before surgery, the patients’ complaints with a recurrent CTS were mainly pain and return of pathological symptoms (tingling, nocturnal pain, etc.) whereas the patients with end stage CTS reported problems of loss of sensation. Both groups (8 patients in each group) reported a limited functional status for activity of daily living (ADL) prior to surgery. Evaluations of sensibility, strength, pain and Boston Carpal Tunnel Questionnaire were made preoperatively and postoperatively at 3, 6 and 12 months. The major clinical issues for both groups were statistically significantly improved after one year, but already significant results were noted after 3 months. We confirm that the hypothenar fat pad flap is a good solution for recurrent CTS. Moreover, end stage CTS could be a new and promising indication for the use of this vascularized flap.

A retrospective follow-up study of the postoperative outcomes of late stage carpal tunnel syndrome

Objective To assess the postoperative outcomes of 56 cases of late stage carpal tunnel syndrome through retrospective follow-up studies and provide treatment guidelines. Methods A retrospective study of 56 cases of late stage carpal tunnel syndrome (thenar muscle atrophy + + + or more) that were surgically treated from February 2010 to December 2011 was conducted. The recovery of thenar muscle atrophy, thenar muscle strength and sensation of the radial three digits was assessed. Results Postoperative follow-up period of these 56 cases ranged from 50 to 71 months, with an average of 64 months. Atrophy of the thenar muscles was entirely reversed in 28 cases (50%) and reversed to (+ + ) in 8 cases (14.3%). No change of thenar muscle atrophy was seen in 20 cases (35.7%). Complete sensory recovery was observed in 51 cases, while the rest 5 cases had near normal sensation. The overall excellent and good rate of postoperative hand function recovery was 85.7%. Conclusion Carpal tunnel release is effective in 85.7% of late stage carpal tunnel syndrome patients. The decision to perform thumb opponensplasty at the same time should be made based on the requirements of individual patients. Key words: Carpal tunnel syndrome; Follow-up studies; Treatment outcome

The application and effectiveness of neuroelectrophysiology and MRI in the early diagnosis of carpal tunnel syndrome

Objective To study the application of neural electromyogram (EMG) and MRI in the diagnosis of carpal tunnel syndrome (CTS) and their correlation. Methods Neuroelectrophysiologic examination was conducted in 36 CTS patients. Based on the electrophysiological staging criteria, these cases were divided into early, intermediate and late stage CTS. These patients along with 40 healthy volunteers were subject to MRI examination to measure and record median nerve swelling rate (MNSR) and median nerve flatness ratio (MNFR). These measurements were compared between these two groups of individuals. Patients with intermediate and late stage CTS underwent surgical carpal tunnel release. Intraoperative findings of the median nerve were compared with the preoperative MRI examination results. Results For early stage CTS patients, MNSR and MNFR were not significantly different from those of the healthy controls. For intermediate and late stage CTS patients, MNSR and MNFR were higher than those of the healthy controls, the difference being statistically significant (P<0.05). Intraoperative observation of the pathological changes of the median nerve was consistent with the preoperative MRI examination results. There was a positive correlation between the distal motor latency (DML) of the median nerve and MNSR and MNFR, and a negative correlation between sensory nerve conduction velocity (SCV) of the median nerve and MNSR. There was no correlation between SCV and MNFR. Conclusion Neural EMG examination can provide evidence for early stage CTS. For intermediate and late stage CTS patients, MRI examination can identify median nerve compression site and etiology, and also provide guidance for surgical decompression. Therefore, MRI is a valuable examination for CTS. However, it cannot replace neural EMG examination for the diagnosis of CTS. Key words: Carpal tunnel syndrome; MRI; Nerve conduction velocity

Efficacy of kinesiotaping in patients with the initial signs of carpal tunnel syndrome

Background. Carpal tunnel syndrome (CTS) is one of the most common tunnel neuropathies. Early symptoms are often limited by periodic and slight discomfort in the area of innervation of a median nerve on the hand, so the patients are not willing to be treated invasively. Thus, a noninvasive therapy, such as kinesiotaping, could be perspective. Objective. Assessment of the efficiency of a kinesiotaping monotheraphy of patients on initial stage of CTS. Materials and methods. We included 120 patients with the initial stage of CTS: 51 men and 69 women aged from 24 till 54 years old. The main group included 70 people, and the control group – 50 patients. The main group was treated within 2 months by kinesiotaping only, control group was observed without any therapeutic intervention. Results. 60 % of the patients from the main group reported beneficial effect of kinesiotaping on clinical symptoms of the CTS. Conclusions. Kinesiotaping monotherapy at initial stages of CTS in our cohort relieves subjective symptoms in the majority of patients. To recommend kinesiotaping as an effective and safe method on initial stages of CTS to patients unwilling to undergo standard invasive treatment methods, a larger multicenter study is needed.

Sonographic findings in the ulnar nerve according to the electrophysiologic stage of carpal tunnel syndrome.

Involvement of the ulnar nerve in patients with carpal tunnel syndrome is controversial. The aim of our study was to evaluate sonographic findings in the ulnar nerve in patients with carpal tunnel syndrome. We performed median and ulnar nerve conduction studies with sonography in 109 hands of 60 patients with clinically suspected carpal tunnel syndrome. Sonographic findings were analyzed with regard to electrophysiologic stages of carpal tunnel syndrome. We found that the sensory conduction velocity of the ulnar nerve decreased as the electrophysiologic stage of carpal tunnel syndrome increased (P = .038), but there was no change in the cross-sectional area of the ulnar nerve at the wrist. The median-to-ulnar nerve cross-sectional area ratio at the wrist showed a significant correlation with the electrophysiologic stage of carpal tunnel syndrome (Spearman r = 0.431; P < .0001), in addition to the median nerve cross-sectional area at the wrist and the wrist-to- forearm median nerve cross-sectional area ratio. In our study, ulnar nerve involvement in patients with carpal tunnel syndrome was shown electrophysiologically but not sonographically. These results suggest that morphologic changes in the ulnar nerve do not occur in carpal tunnel syndrome, although functional changes may occur.

Evaluation of the function status of the ulnar nerve in carpal tunnel syndrome.

Many carpal tunnel syndrome (CTS) patients have symptoms in both the median and ulnar digits more frequently than in the median digits alone. This is possibly because of close anatomical contiguity of the carpal tunnel and Guyon's canal, and the high pressure may also affect the latter, causing indirect compression of ulnar nerve fibers. Thus, we evaluated the functional status of the ulnar nerve in patients with CTS in order to investigate the relationship between ulnar nerve impairment and sensory symptoms of the ulnar territory. Electrophysiological studies were conducted in CTS patients and healthy controls. CTS patients were divided into the mild/moderate group and severe group; they were further divided into the symptomatic and asymptomatic subgroups according to the sensory symptom of the fifth digit region. The findings suggest that CTS patients could have coexisting ulnar nerve wrist entrapments that might exacerbate the severity of CTS. Sensory impairment in the ulnar territory was observed more frequently in the mild/moderate stage of CTS, which is associated with ulnar nerve involvement. These findings also suggest that damage to the ulnar nerve fibers caused by compression forces in Guyon's canal may underlie the ulnar spread of symptoms in CTS.

Low sensitivity of F-wave in the electrodiagnosis of carpal tunnel syndrome

ObjectivePrevious studies showed “F-wave inversion” (F-INV) as a sensitive method in the electrodiagnosis of early stage of carpal tunnel syndrome (CTS). This study aimed at evaluating the sensitivity and specificity of F-wave and nerve conduction velocity (NCV) testing in CTS. MethodsWe consecutively enrolled 244 cases and 108 controls. F-waves analysis included: Fwave minimum and mean latencies, F-wave persistence and chronodispersion, mean-F/CMAP amplitude ratio, F-INV. Specificity and sensitivity of F-waves parameters were calculated in the whole sample of CTS patients and by grouping the patients according to CTS severity. Multivariate logistic regression was also performed using F-INV as a dependent variable. ResultsIn the whole sample the sensitivity of F-mean-INV and of median–ulnar NCV comparative testing was 50.8% and 93.7%, respectively. F-INV sensitivity dropped to 8% in CTS early stage. F-INV could be predicted only by distal motor latency of the median nerve. The sensitivity of all F-wave parameters increased only in the most severe stages of CTS. ConclusionsThis study does not confirm the electrodiagnostic usefulness of F-INV in early stage of CTS. All F-wave parameters, including F-INV, are much less sensitive than conventional NCV in CTS electrodiagnosis. F-wave does not add further useful information specifically related to CTS.

The Usefulness of Terminal Latency Index of Median Nerve and F-Wave Difference Between Median and Ulnar Nerves in Assessing the Severity of Carpal Tunnel Syndrome

The calculated electrophysiological parameters, such as terminal latency index (TLI), residual latency, modified F ratio, and F-wave inversion, have been investigated as a diagnostic tool for detection of early stage of carpal tunnel syndrome (CTS) in the literature. However, the correlation of these calculated electrophysiological parameters with the clinical severity of CTS has not been reported. The aim of this study was to determine the correlation of the calculated electrophysiological parameters and clinical severity in patients with CTS. A retrospective study was performed with 212 hands of 106 CTS patients. The CTS hands were classified as asymptomatic, mild, moderate, and severe according to the clinical severity. The distal motor latency and distal motor conduction velocity of median nerve, minimal F-wave latency of median and ulnar nerves, and sensory nerve conduction velocity in the finger-wrist and palm-wrist segment of median nerve (SNCV f-w and SNCV p-w) were obtained in a conventional nerve conduction study. The TLI, residual latency, and modified F ratio of the median nerve and the difference of minimal F-wave latencies between the median and ulnar nerves (F-diff M-U) were calculated. The distal motor latency, residual latency, and F-diff M-U were significantly increased according to the clinical severity of CTS. The motor conduction velocity, SNCV p-w, SNCV f-w, TLI, and modified F ratio were significantly decreased according to the clinical severity of CTS. In analyses of variance and Kruskal-Wallis test, we used the Scheffe test as a post-hoc comparison analysis. The TLI, F-diff M-U, and SNCV f-w showed a significant difference among all groups of each CTS severity. The sensitivity, specificity, and cut-off value of TLI, F-diff M-U, and SNCV f-w between asymptomatic and mild, mild and moderate, and moderate and severe CTS groups were calculated by using receiver operating characteristic curve analysis. The cut-off values of TLI, F-diff M-U, and SNCV f-w between the asymptomatic and mild CTS groups were, respectively, 0.33 millisecond, 0.3 millisecond, and 40 cm/second. The cut-off values of TLI, F-diff M-U, and SNCV f-w between mild and moderate were, respectively, 0.27 millisecond, 2.3 milliseconds, and 34.8 cm/second. The cut-off values of TLI, F-diff M-U, and SNCV f-w between moderate and severe CTS groups were, respectively, 0.20 millisecond, 4.2 milliseconds, and 26.4 cm/second. We found that calculated electrophysiological parameters of conventional nerve conduction study could be a good indicator to determine the severity of CTS.