Ultrasound Elastographic Evaluation in the Diagnosis of Carpal Tunnel Syndrome: Initial Findings

The purpose of this study was to investigate ultrasound (US)- and US elastography-detected changes in the median nerve of patients with carpal tunnel syndrome (CTS). Seventy-four wrists of 41 female patients with CTS (mean age, 47.73 ± 11.45 y) and 45 wrists of 24 asymptomatic female controls (mean age, 42.83 ± 10.66 y) were examined with US and US elastography. Electromyography results confirmed the diagnosis of CTS in the patients. The mean median nerve perimeter (MN-P = 15.26 ± 2.18 mm) and median nerve cross-sectional area (MN-CSA = 11.81 ± 4.05 mm²) of patients with CTS were higher than those of controls (12.08 ± 1.54 mm and 7.76 ± 1.40 mm², respectively) (p < 0.05). Mean tissue strain was lower in the patients with CTS (0.094 ± 0.045 than in the controls (0.145 ± 0.068) (p < 0.05). The most sensitive cut-off value for tissue strain was 0.0635, and the most specific was 0.19. US and US elastography, in addition to electromyography, proved to be beneficial in the diagnosis of CTS. US elastography is a new technique that may well find a place in the diagnosis of nerve entrapment syndromes.     

Nerve Echogenicity: Changes in High-Resolution Nerve Ultrasound in Carpal Tunnel Syndrome after Surgery

The aim of our prospective study was to detect changes in nerve echogenicity of the median nerve before and after successful surgery in patients with carpal tunnel syndrome (CTS) using high-resolution ultrasound. Fifteen patients with a definite diagnosis of CTS who underwent surgery were scanned by one examiner with high-resolution ultrasound, and images were analyzed by two blinded raters using ImageJ to assess the echogenicity of the median nerve (fraction of black) with a semiautomated thresholding technique before and 3 mo after surgery compared with 15 controls. In CTS patients, nerve echogenicity before surgery was significantly lower compared with that of controls (fraction of black: mean 63.9 vs. 44.6, p < 0.0001). Three months after surgery nerve echogenicity significantly increased (fraction of black was lower, mean 55.5; p < 0.0001) as a possible sign of reduction of intraneural edema, but did not reach the values of healthy controls. Semi-automated evaluation of the echogenicity of the median nerve may be used as a marker of successful carpal tunnel release. Further studies are warranted to detect how nerve echogenicity changes after unsuccessful carpal tunnel release.     

Reliability of Automatic Vibratory Equipment for Ultrasonic Strain Measurement of the Median Nerve

The objective of this study was to test the reliability of ultrasonic median nerve strain measurements using automatic vibratory equipment. Strain ratios of the median nerve in the carpal tunnel model and the reference coupler were measured at three different settings of the transducer: 0, +2 and +4 mm (+ = compressing the model down 2–4 mm initially). After measurement of the carpal tunnel model, a +4-mm setting was chosen for in vivo measurement. The median nerve strains of 30 wrists were measured by two examiners using the equipment. Intra- and inter-examiner correlation coefficients (CCs) for the strain ratios were calculated. The closest ratio was found in the +4-mm placement (strain ratio: 0.73, Young's modulus ratio: 0.79). The intra-examiner CC was 0.91 (p < 0.01), and the inter-examiner CCs were 0.72–0.78 (p < 0.01). The automatic vibratory equipment was useful in quantifying median nerve strain at the wrist.     

High-resolution ultrasonography of the carpal tunnel

Twenty-eight wrists of 25 patients with carpal tunnel syndrome (CTS) and 28 wrists of 14 normal control subjects were studied with high-frequency real-time ultrasonography. Three general findings could be observed in CTS, regardless of its cause: swelling of the median nerve at the entrance of the carpal tunnel; flattening of the median nerve in the distal carpal tunnel; and increased palmar flexion of the transverse carpal ligament. Quantitative analysis proved these findings to be significant. We conclude that high-resolution sonography is able to diagnose median nerve compression in the carpal tunnel syndrome and to detect some of its potential causes.     

Utility of Ultrasound Elastography in Evaluation of Carpal Tunnel Syndrome: A Systematic Review and Meta-analysis

We systematically reviewed observational studies investigating ultrasound elastography for median nerves in the carpal tunnel syndrome (CTS) population. PubMed and Embase were studied from the earliest record to April 2019. The primary outcome was the comparison of elasticity of the median nerve between participants with and without CTS, quantified by the standardized mean difference (SMD) and its 95% confidence interval. The median nerve is considered to be stiffer in the CTS population when the SMD of tissue strain is negative, or that of strain ratio, shear modulus and shear wave velocity are positive. The present meta-analysis included 17 studies, evaluating 1401 wrists. Our result showed that regardless of the ultrasound elastography mode (tissue strain, strain ratio, shear modulus and shear wave velocity) used, median nerves at the wrist level in patients with CTS were consistently stiffer than those in healthy controls. Importantly, ultrasound elastography revealed its potential in differentiating CTS of different severity.     

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

Objectives

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).

Methods

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.

Results

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 45.9 years, range 23–73 years), 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 3.250 m/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.

Conclusion

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.

     

Thirty Minutes of Sub-diastolic Blood Flow Occlusion Alters Carpal Tunnel Tissue Function and Mechanics

There is evidence that carpal tunnel syndrome (CTS) development is driven by vascular factors, specifically those resulting from ischemia and edema. The purpose of this study was to investigate the vascular hypothesis of CTS development by quantifying the temporal effects of 30 min of sub-diastolic brachial blood flow occlusion on median nerve edema, intraneural blood flow velocity, nerve function as measured through nerve conduction study (NCS), tendon–connective tissue mechanics and carpal tunnel tissue stiffness. Forty healthy volunteers underwent 30 min of sub-diastolic brachial occlusion while an NCS and ultrasound examination were performed consecutively every 5 min. Motor latency (p < 0.001), sensory conduction velocity (p < 0.001), sensory amplitude (p = 0.04), nerve blood flow (p < 0.001), peak relative flexor digitorum superficialis tendon–sub-synovial connective tissue displacement (p = 0.02) and shear strain (p = 0.04) were significantly affected by partial ischemia. Our results highlight the dependency of carpal tunnel tissue function on adequate blood flow.     

高频超声在腕管综合征病因学评价中的应用

目的探讨高频超声在评价腕管综合征病因中的作用。 方法选取2015年3月至2019年12月在解放军总医院经电生理检查诊断或手术证实腕管综合征的患者,首先对腕管进行灰阶超声检查,观察腕管内正中神经的位置、走向,神经受压情况、神经束结构、神经外膜回声以及神经周围结构的异常,横切面扫查腕管及正中神经时观察正中神经横截面情况、测量豌豆骨平面正中神经的横截面积以及观察神经周围结构的异常;应用能量多普勒超声以观察正中神经及腕管内其他结构的血流情况。采用独立样本t检验比较患侧腕和无症状侧腕豌豆骨平面正中神经横截面面积的差异。利用受试者操作特征（ROC）曲线分析豌豆骨平面正中神经的横截面面积的诊断价值并找出最佳的诊断界值。 结果腕管综合征患者63例,共95侧腕。腕管综合征患者高频超声表现为腕管内正中神经的卡压近端肿胀、增粗,神经束结构模糊,神经外膜增厚。能量多普勒超声显示正中神经内血流信号增加。患侧腕与无症状侧腕的豌豆骨平面正中神经横截面面积比较［（15.91±5.95）mm² vs（8.71±1.62）mm²］,差异具有统计学意义（t=-2.51,P＜0.001）,ROC曲线下面积为0.946,截断值为10.5 mm2时,敏感度为89.5%,特异度为83.9%。高频超声诊断为特发性腕管综合征者73侧腕（76.8%,73/95）,可明确诊断病因的共22侧腕（23.2%,22/95）,其中13侧腕（13.7%,13/95）为腕管内屈肌腱腱鞘炎,1侧腕（1.1%,1/95）为腕管内屈肌腱腱鞘积液,2侧腕（2.1%,2/95）为腕管内腱鞘囊肿,1侧腕（1.1%,1/95）为腕管内实性肿块,2侧腕（2.1%,2/95）为腕管内指浅屈肌肌腹过低,2侧腕（2.1%,2/95）为正中神经高位分叉伴永存正中动脉,1侧腕（1.1%,1/95）为桡骨远端术后瘢痕压迫正中神经。 结论高频超声可作为评估腕管综合征病因的一种手段。     

Idiopathic Carpal Tunnel Syndrome: Evaluation of the Depth of the Carpal Tunnel by Ultrasonography

The objective of the work described here was to evaluate the depth of the carpal tunnel (DCT) in patients with idiopathic carpal tunnel syndrome (CTS) and healthy volunteers by ultrasonography (US), through measurement of the distance from the flexor retinaculum to the surface of the capitate bone at the carpal tunnel outlet, and compare it with other ultrasonographic and electrophysiologic parameters in CTS. The study was conducted in 60 non-diabetic patients with idiopathic carpal tunnel syndrome (unilateral n = 37, bilateral n = 23) evidenced by electrophysiologic diagnosis according to the criteria of the American Association of Electrodiagnostic Medicine (AAEM). Furthermore, 40 hands from 20 healthy volunteers were examined. Median nerve cross-sectional area (CSA); flattening ratio (FR), the ratio of the length to the width of the median nerve; and DCT at the canal outlet were measured for all participants. The mean age was 35.6 ± 9.48 y. The female-to-male ratio was 47:13 in the CTS patients. The sensitivity and specificity were 82% and 95% for CSA, 75% and 60% for FR and 75% and 87.5% for DCT, respectively. Differences between patients and healthy controls were significant for all three parameters, greatest for DCT, followed by CSA and then FR. We conclude that DCT increased in CTS and this new parameter is comparable in sensitivity and specificity to CSA and FR. DCT increased independently of the cause of the CTS (decrease in size of canal or increase in contents).     

Ultrasound elastographic evaluation of the median nerve in hemodialysis with carpal tunnel syndrome

Purpose

The aim of this study was to compare the elasticity of the median nerve (MN) between hemodialysis (HD) patients without carpal tunnel syndrome (CTS) and with CTS, and to evaluate the diagnostic usefulness of the elasticity of the MN in HD-CTS.

Materials and methods

The MN in 22 HD patients without CTS and 49 HD-CTS patients was studied. The cross-sectional area (CSA) and the elasticity of the MN, which was measured as the subcutaneous fat/median nerve (SF/MN) strain ratio, were evaluated.

Results

The mean SF/MN strain ratio in the groups that had received hemodialysis for 0–5, >5–10, and >10–15 years was 1.4 ± 0.28, 1.7 ± 0.18, and 2.0 ± 0.67, respectively. The mean CSA of the MN in the three groups was 9.9 ± 1.30, 11.6 ± 1.61, and 13.4 ± 2.14 mm², respectively. The presence of CTS was predicted by means of SF/MN strain ratio and CSA cutoff values of 1.8 and 11 mm², respectively. Both the SF/MN strain ratio and the CSA in the patients with CTS were higher than those in the patients without CTS (P < 0.05). The sensitivity and specificity of the SF/MN strain ratio and CSA of the MN were 75 and 92 % and 79.2 and 84 %, respectively.

Conclusion

Sonoelastography helps to improve the diagnostic accuracy of the ultrasonographic assessment of CTS.

     

Reduced longitudinal excursion of the median nerve in carpal tunnel syndrome

OBJECTIVE: To determine if longitudinal excursion of the median nerve is reduced in patients with carpal tunnel syndrome (CTS). DESIGN: Case-control study. SETTING: University human movement laboratory. PARTICIPANTS: Nineteen patients with CTS (8 men, 11 women; mean age, 57+/-15 y), and 37 healthy controls (8 men, 29 women; mean age, 48+/-10 y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Longitudinal excursion of the median nerve, and the ratio of nerve to flexor digitorum superficialis tendon excursion at the carpal tunnel evoked by finger extension. Measurements were taken using a validated Doppler ultrasound technique, and tests were conducted with the elbow positioned in extension and flexion. RESULTS: Mean longitudinal excursion of the median nerve was significantly greater in controls (11.2+/-2.8 mm) than patients (8.3+/-2.6 mm) with the elbow extended (P=.013), but not with the elbow flexed (controls, 12.5+/-2.5 mm; patients, 10.2+/-3.1 mm; P=.089). Mean nerve/tendon excursion ratios were significantly greater in controls (.32+/-.07) than patients (.23+/-.06), with the elbow extended (P<.001), and flexed (controls, .36+/-.06; patients, .28+/-.10; P=.019). Discriminant analysis identified that 11 (58%) of the 19 patients and 3 (8%) of the 37 controls showed a nerve/tendon excursion ratio of .25 or less when tested with the elbow in extension. CONCLUSIONS: Reduced longitudinal excursion of the median nerve at the carpal tunnel was identified in a substantial proportion of patients with CTS. Further studies are merited to determine if reduced median nerve excursion at the carpal tunnel is clinically relevant in CTS, and can be influenced by movement-based interventions.     

Ultrasonography for diagnosing carpal tunnel syndrome: a meta-analysis of diagnostic test accuracy

Ultrasonography is widely used to diagnose carpal tunnel syndrome (CTS), a common peripheral neuropathy, but the reported diagnostic accuracy varies. This meta-analysis focused on the diagnostic test accuracy of ultrasonography for diagnosing CTS. Structured searches of PubMed for 1990-2010 were done and the data were extracted and meta-analyzed by pooling estimates of sensitivity, specificity, likelihood ratios and diagnostic odds ratios. Diagnostic performance was also judged by using a summary receiver operating characteristic curve. Twenty-eight trials involving 3995 wrists were included. A greater cross-sectional area (CSA) of the median nerve at the carpal tunnel inlet (CSA-I) and a greater flattening ratio at the level of the hamate were seen in CTS wrists than in control wrists. A CSA-I ≥9 mm(2) is the best single diagnostic criterion, with a diagnostic odds ratio of 40.4 (sensitivity 87.3%, specificity 83.3%).     

A comparison of the benefits of sonography and electrophysiologic measurements as predictors of symptom severity and functional status in patients with carpal tunnel syndrome

Kaymak B, Özçakar L, Çetin A, Candan Çetin M, Ak?nc? A, Hasçelik Z. A comparison of the benefits of sonography and electrophysiologic measurements as predictors of symptom severity and functional status in patients with carpal tunnel syndrome.

Objectives

To clarify whether sonography or electrophysiologic testing is a better predictor of symptom severity and functional status in carpal tunnel syndrome (CTS) and to assess the diagnostic value of sonography in patients with idiopathic CTS.

Design

Cross-sectional.

Setting

University hospital physical medicine and rehabilitation clinic.

Participants

Thirty-four hands with CTS and 38 normative hands were evaluated.

Interventions

Not applicable.

Main Outcome Measures

The Boston Carpal Tunnel Questionnaire, which comprised symptom severity and functional status scale, was applied to CTS patients. Bilateral upper-extremity nerve conduction studies of median and ulnar nerves and sonographic imaging of the median nerve were performed in all participants. Sonographic evaluation was performed by a physician blinded to the physical and electrophysiologic findings of the subjects.

Results

Cross-sectional areas (CSAs) of the median nerve at the carpal tunnel entrance and proximal carpal tunnel were 12.5±2.6 and 10.6±2.6 versus 15.6±4.2 and 11.5±3.2 in CTS patients versus controls, respectively. Increased CSA of the median nerve at the carpal tunnel entrance (P<.002) and at the proximal carpal tunnel (P<.000) were detected in the hands with CTS. Flattening ratios did not differ in a statistically significant manner between the groups (P>.05). The best predictor of symptom severity was median nerve sensory distal latency and that of functional status was median nerve motor distal latency. The optimum cutoff value for median nerve CSA was 11.2mm² at the carpal tunnel entrance and 11.9mm² at the proximal carpal tunnel. Sensitivity, specificity, and positive and negative predictive values at the proximal carpal tunnel (88%, 66%, 71%, 80%, respectively) were higher than those at the carpal tunnel entrance (68%, 62%, 65%, 66%, respectively).

Conclusions

The best predictors of symptom severity and functional status in idiopathic CTS seem to be the electrophysiologic assessments rather than sonographic measurements. On the other hand, sonography may be helpful in the diagnosis of idiopathic CTS.     

Does wrist immobilization following open carpal tunnel release improve functional outcome? A literature review

Carpal Tunnel Syndrome (CTS) is a compressive neuropathy of the median nerve in the carpal tunnel. It is the most common peripheral entrapment neuropathy. The surgical management includes dividing the flexor retinaculum to decompress the median nerve. Post-operative mobilization of the wrist is controversial. Some surgeons splint the wrist for 2–4 weeks whilst others encourage early mobilization. The literature has been inconclusive as to which method is most beneficial. The purpose of this study is to review the literature regarding the effectiveness of wrist immobilization following open carpal tunnel decompression. We reviewed all published clinical trials claiming to evaluate the mobility status following open carpal tunnel release. Studies not in the English language as well as those with small number of patients (n < 30) were excluded. There were five studies that fulfilled the eligibility criteria and were included in this review. We conclude that there is no beneficial effect from post-operative immobilization after open carpal tunnel decompression when compared to early mobilization.     

Dimensional changes of the carpal tunnel and median nerve during manual mobilization of the carpal bones — Anatomical study

Study designCross-sectional study.BackgroundThe carpal tunnel is a clinically important fibro-osseous conduit for the median nerve and associated tendons. It is mechanically dynamic and therapeutic manual techniques that appear to move and change tunnel shape is part of clinical practice.ObjectivesTo measure changes in dimensions of the carpal tunnel and median nerve with manual mobilization of the carpal bones in cadavers.MethodsA total of 20 cryopreserved upper extremities from cadaveric specimens were used in the study. The wrist was cut using an anatomical saw at the level of the pisiform. Measurements of the cross-sectional area (CSA), anteroposterior diameter (APD), transverse diameter (TD), perimeter, flattening ratio and circularity of the carpal tunnel and of the median nerve, were taken, both in the anatomical position of the wrist and during the mobilization technique of the carpal bones.ResultsDuring the mobilization technique, the tunnel CSA (p < 0.011), APD (p < 0.001) and circularity (p < 0.001) significantly increased, while TD (p < 0.001), perimeter (p < 0.004) and flattening ratio (p < 0.001), decreased. The median nerve showed similar behavioral tendencies to the tunnel but only the CSA (p < 0.005), APD (p < 0.005) and flattening ratio (p < 0.004) of the nerve showed significant differences.ConclusionApplication of external manually applied compressive force across the wrist can increase the CSA of the carpal tunnel and the median nerve in cadavers. These results are consistent with other studies in which similar results were found non-invasively using ultrasound.     

高频超声对ECTR术后神经解剖学参数的动态评估价值

目的 探讨高频超声对关节镜下腕管松解术后神经解剖学参数的动态评估价值。方法 随访31例（44腕）腕管综合症患者术前3天,术后2周、4周、3月、6月、1年正中神经卡压近端水肿范围、腕管入口正中神经直径及横截面积,并根据横截面积绘制高频超声诊断腕管综合征ROC曲线。结果 术后各神经解剖学参数逐步改善,术后1个月至3个月各解剖学参数改善最明显。高频超声对CTS具有较高的诊断效能。结论 高频超声能够对关节镜下腕管松解术后神经解剖学参数进行有效地的动态评估。     

Bifid Median Nerve in Patients With Carpal Tunnel Syndrome

Objective. The aim of this study was to investigate the frequency of the anatomic variation of a bifid median nerve in patients with carpal tunnel syndrome (CTS) and to determine the size criteria for sonography. Methods. On axial sonograms of 320 hands of 170 patients with CTS and 240 hands of 120 unaffected individuals, the median nerve was evaluated morphologically for a bifid median nerve, and the cross‐sectional area was measured at 3 levels (radial‐ulnar junction, pisiform, and hook of the hamate). Electrophysiologic studies were performed in addition to clinical and sonographic evaluations in all patients, controls with a bifid median nerve, and controls with a cross‐sectional area of greater than 0.09 cm². Results. A bifid median nerve was seen in 32 (19%) of 170 patients and 11 (9%) of 120 controls. It occurred relatively frequently in patients with CTS (P < .01). The cross‐sectional area of the bifid median nerve was relatively higher than that of the nonbifid median nerve in controls at 2 of the 3 levels (P < .001; P = .226; P < .01). The cutoff values for the cross‐sectional area at the level of the pisiform were 0.11 cm² (sensitivity, 90%; specificity, 99%; P < .001) for patients with a bifid median nerve and 0.10 cm² (sensitivity, 98%; specificity, 81%; P < .001) for patients with a nonbifid median nerve. Conclusions. A bifid median nerve occurs relatively frequently in patients with CTS. It may facilitate compression of the median nerve in the carpal tunnel because of its relatively higher cross‐sectional area compared with a nonbifid median nerve. The size criterion for CTS in patients with a bifid median nerve is slightly higher than in those with a nonbifid median nerve.     

Transverse Ultrasound Assessment of Median Nerve Deformation and Displacement in the Human Carpal Tunnel during Wrist Movements

The symptoms of carpal tunnel syndrome, a compression neuropathy of the median nerve at the wrist, are aggravated by wrist motion, but the effect of these motions on median nerve motion are unknown. To better understand the biomechanics of the abnormal nerve, it is first necessary to understand normal nerve movement. The purpose of this study was to evaluate the deformation and displacement of the normal median nerve at the proximal carpal tunnel level on transverse ultrasound images during different wrist movements, to have a baseline for comparison with abnormal movements. Dynamic ultrasound images of both wrists of 10 asymptomatic volunteers were obtained during wrist maximal flexion, extension and ulnar deviation. To simplify the analysis, the initial and final shape and position of the median nerve were measured and analyzed. The circularity of the median nerve was significantly increased and the aspect ratio and perimeter were significantly decreased in the final image compared with the first image during wrist flexion with finger extension, wrist flexion with finger flexion and wrist ulnar deviation with finger extension (p < 0.01). There were significant differences in median nerve displacement vector between finger flexion, wrist flexion with finger extension and wrist ulnar deviation with finger extension (all p's < 0.001). The mean amplitudes of median nerve motion in wrist flexion with finger extension (2.36 ± 0.79 normalized units [NU]), wrist flexion with finger flexion (2.46 ± 0.84 NU) and wrist ulnar deviation with finger extension (2.86 ± 0.51 NU) were higher than those in finger flexion (0.82 ± 0.33 NU), wrist extension with finger extension (0.77 ± 0.46 NU) and wrist extension with finger flexion (0.81 ± 0.58 NU) (p < 0.0001). In the normal carpal tunnel, wrist flexion and ulnar deviation could induce significant transverse displacement and deformation of the median nerve.     

The value of sonographic quantitative parameters in the diagnosis of carpal tunnel syndrome in the Vietnamese population

ObjectiveTo examine the value of ultrasound (US) in the diagnosis of carpal tunnel syndrome (CTS) in the Vietnamese population.MethodsThis prospective cross-sectional study involved 42 wrists of 25 patients with idiopathic CTS evaluated by US. In addition, 38 wrists of 22 healthy volunteers were included as the control group.ResultsSignificant differences in the median nerve cross-sectional area (CSA) at different levels were found between patients with CTS and controls. Using a cut-off value of 9.5 mm² for the median nerve CSA at the pisiform (p-CSA), US had a sensitivity and specificity of 95.2% and 97.4%, respectively, for the diagnosis of CTS. Area under the curve analysis revealed a sensitivity and specificity of 100% and 95.4%, respectively, for the prediction of severe CTS using a p-CSA of >15.5 mm².ConclusionsThe median nerve CSA is a highly accurate parameter in the diagnosis of CTS. We recommend using a p-CSA of >9.5 mm² as a diagnostic criterion for CTS and a p-CSA of >15.5 mm² as a marker for severe CTS in the Vietnamese population.Research Registry number: 7261     

Randomized controlled trial of nocturnal splinting for active workers with symptoms of carpal tunnel syndrome

OBJECTIVES: To determine whether nocturnal splinting of workers identified through active surveillance with symptoms consistent with carpal tunnel syndrome (CTS) would improve symptoms and median nerve function as well as impact medical care. DESIGN: Randomized controlled trial. SETTING: A Midwestern auto assembly plant. PARTICIPANTS: Active workers with symptoms suggestive of CTS based on a hand diagram. INTERVENTION: The treatment group received customized wrist splints, which were worn at night for 6 weeks; the control group received ergonomic education alone. MAIN OUTCOME MEASURES: Change in wrist, hand, and/or finger discomfort, carpal tunnel symptom severity index, median sensory nerve function, and the percentage of subjects who had carpal tunnel release surgery. RESULTS: The splinted group, unlike the controls, had a significant reduction in wrist, hand, and/or finger discomfort and a similar trend in the Levine carpal tunnel symptom severity index, which was maintained at 12 months. A secondary analysis showed that more median nerve impairment at baseline was associated with less clinical improvement among controls but not among the splinted group. CONCLUSIONS: Workers identified with CTS symptoms in an active symptom surveillance tended to benefit from a 6-week nocturnal splinting trial, and the benefits were still evident at the 1-year follow-up. The splinted group improved in terms of hand discomfort regardless of the degree of median nerve impairment, whereas the controls showed improvement only among subjects with normal median nerve function. Results suggest that a short course of nocturnal splinting may reduce wrist, hand, and/or finger discomfort among active workers with symptoms consistent with CTS.