Magnetic resonance imaging compared with electrodiagnostic studies in patients with suspected carpal tunnel syndrome: predicting symptoms, function, and surgical benefit at 1 year

T2 magnetic resonance imaging mapping and morphology of the median nerve before and after surgery in carpal tunnel syndrome

INTRODUCTION/AIMS

T2 magnetic resonance imaging (MRI) mapping has been applied to carpal tunnel syndrome (CTS) for quantitative assessment of the median nerve. However, quantitative changes in the median nerve before and after surgery using T2 MRI mapping remain unclear. We aimed to investigate whether pathological changes could be identified by pre- and postoperative T2 MRI mapping of the median nerve in CTS patients after open carpal tunnel release.

METHODS

This was a prospective study that measured median nerve T2 and cross-sectional area (CSA) values at the distal carpal tunnel, hamate bone, proximal carpal tunnel, and forearm levels pre- and postoperatively. Associations between T2, CSA, and nerve conduction latency were also evaluated.

RESULTS

A total of 36 patients with CTS (mean age, 64.5 ± 11.7 years) who underwent surgery were studied. The mean preoperative T2 values significantly decreased from 56.3 to 46.9 ms at the proximal carpal tunnel levels (p = .001), and from 52.4 to 48.7 ms at the hamate levels postoperatively (p = .04). Although there was a moderate association between preoperative T2 values at the distal carpal tunnel levels and distal motor latency values (r = -.46), other T2 values at all four carpal tunnel levels were not significantly associated with CSA or nerve conduction latency pre- or postoperatively.

DISCUSSION

T2 MRI mapping of the carpal tunnel suggested a decrease in nerve edema after surgery. T2 MRI mapping provides quantitative information on the median nerve before and after surgery.

Understanding carpal tunnel syndrome

ABSTRACT

Carpal tunnel syndrome (CTS) is an entrapment neuropathy affecting the median nerve. Prevalence is estimated at 4% to 5% of the population. A solid understanding of the anatomy, presentation, and diagnostics is key to efficient diagnosis and appropriate referral. Both surgical and nonsurgical interventions have led to improved clinical outcomes. Clinicians who have an in-depth knowledge of CTS symptoms and treatment options can prepare patients and streamline referrals for improved patient outcomes.

The association of sensory phenotype and concomitant mood, sleep and functional impairment with the outcome of carpal tunnel surgery

BACKGROUND

Up to 25% of people who have had carpal tunnel release surgery (CTR) fail to report improvement; however, evidence for prognostic indicators in this surgical cohort is limited. To identify candidate prognostic factors, this study investigated the association of quantitative sensory testing (QST) derived sensory phenotype and attendant impairment with patient-reported surgical outcome.

METHODS

With ethical approval and informed consent, this prospective observational longitudinal study recruited patients from two London hospitals. Multimodal phenotyping measures including quantitative sensory testing (QST), pain parameters, insomnia, pain-related worry, mood and function, were evaluated prior to; and at 3- and 6-months post-surgery. Pain in median nerve distribution with electrophysiologically confirmed conduction delay and DN4 score ≥ 4 was defined as neuropathic. Primary outcome was patient-rated change at 6 months, dichotomised as poor outcome; "worse" or "no change" and good outcome; "slightly better", "much better" or "completely cured".

RESULTS

Seventy-six patients participated. Prior to surgery, substantial heterogeneity in established categories of somatosensory function was observed with 21% of participants categorised as having a healthy sensory phenotype; 29% with thermal hyperalgesia; 32% mechanical hyperalgesia and 18% sensory loss. Seventy six percent of participants were classified as having neuropathic pain, 33% with high levels of pain related worry and 64% with clinical insomnia. Observed differences in pain, sleep impairment, psychological factors and function, between sensory phenotypic groups, was not significant. At 3- and 6-months post-surgery there was significant improvement in all phenotyping measures with a moderate to large effect size. Thermal and mechanical measures of somatosensation improved (p < 0.001), as did functional ability (p < 0.001). Symptom severity diminished (p < 0.001), as did pain-related worry (p < 0.001), anxiety (p = 0.02) and insomnia (p < 0.001). Patient-rated surgical outcome was good in 92% of the cohort, poor in 8%. Baseline sensory phenotype category was not associated with surgical outcome however pain-related worry, anxiety and functional interference were significantly associated with outcome (p ≤ 0.05).

CONCLUSION

In patients undergoing carpal tunnel surgery, pain-related worry, anxiety and pain functional interference are candidate prognostic outcome factors and require further elucidation.

MRI of the Carpal Tunnel 3 and 12 Months After Endoscopic Carpal Tunnel Release

OBJECTIVE. The purpose of this study was to study changes in the median nerve, retinaculum, and carpal tunnel on MRI after successful endoscopic carpal tunnel release (ECTR). SUBJECTS AND METHODS. In this prospective study, 35 wrists in 32 patients (five men, 27 women; mean age, 56.7 ± 6.8 [SD] years) with nerve conduction test-confirmed primary carpal tunnel syndrome were evaluated from May 2013 to September 2016. Clinical scores ranging from 0 to 4 (no improvement to symptoms completely resolved) and MRI morphologic features of median nerve and carpal tunnel were evaluated at baseline and 3 and 12 months after ECTR. The paired t test was used to compare MRI parameters before and after ECTR and their relationships to clinical improvement scores. RESULTS. All patients' conditions improved after ECTR with mean clinical improvement scores of 2.94 ± 1.0 at 3 months and 3.49 ± 0.56 at 12 months. Although median nerve swelling did decrease proximally, the nerve remained swollen (> 15 mm²) and flattened in all areas, even 12 months after ECTR. Additional changes occurred in median nerve caliber-change ratio, relative signal intensity, and carpal tunnel cross-sectional area. A retinacular gap was present in 33 (94%) wrists 3 months and six (17%) wrists 12 months after ECTR, and increased retinacular bowing persisted. CONCLUSION. After ECTR, undue swelling and flattening of the median nerve persist as long as 12 months after surgery, even in patients with a good surgical outcome. One should be wary of using these MRI findings as signs of persistent neural compression. The retinaculum reforms in most patients within 12 months of surgery but with a more bowed configuration.

Carpal tunnel syndrome and associated nail changes: Review and examples from the author's practice

Carpal tunnel syndrome (CTS) is commonly seen by general practitioners and often presents with neurologic symptoms of nocturnal pain and paresthesia along the median nerve distribution. Approximately 20% of patients also present with cutaneous findings (ulcerations, blistering, sclerodactyly, nail dystrophy) characterizing a severe form called necrotic CTS. Necrotic CTS can also be associated with bone changes (acro-osteolysis). In the author's practice, combined nail and skin findings are not an uncommon presentation of CTS, although this form remains overlooked and underreported in the dermatological textbooks and studies. This manuscript aims to review the literature on CTS cases, with a specific focus on using associated nail findings as diagnostic clues. The literature review along with a few additional recent cases from the author's practice demonstrate that CTS is frequently accompanied by a variety of nail changes including koilonychia, longitudinal fissuring, Beau's lines, onychomadesis, melanonychia, nail thickening, hyperkeratosis, and ischemic ulcerations with paronychia. Furthermore, when these changes are limited to the second and third fingernails, they should prompt the diagnosis of CTS. Once suspected, diagnostic evaluation is not difficult and surgical management can resolve cutaneous findings and prevent irreversible changes such as acro-osteolysis.

Evaluation of thenar muscles by MRI in carpal tunnel syndrome

In the present study, the thenar muscles were evaluated using magnetic resonance imaging (MRI), in addition, the correlations between thenar muscle changes, clinical findings and electrodiagnostic results from patients with carpal tunnel syndrome were investigated. The subjects were 13 patients (17 wrists) who were clinically diagnosed with carpal tunnel syndrome. In all patients, a medical history was obtained and physical examination was performed, in addition to assessment using the Kapandji scoring system, visual analogue scale (VAS), quick-disabilities of the arm, shoulder and hand (Q-DASH) score, electrodiagnostic results of the median nerve, and MRI of the thenar muscles. Thenar muscle volume was not significantly correlated with clinical data or the electrodiagnostic results. The thenar muscle major axis was significantly correlated with grasp power (P<0.05) and the Kapandji score (P<0.05), while the thenar muscle minor axis was significantly correlated with abductor pollicis brevis distal motor latency (APB DML) (P<0.01). In addition, the thenar muscle minor axis/thenar muscle major axis ratio was significantly correlated with APB DML and Kanatani's stage. Notably, thenar muscle thinness was significantly correlated with the severity of electrodiagnostic changes, while the grasp power and Kapandji score were correlated with thenar muscle thickness. Furthermore, it was demonstrated that thenar muscle thinness was significantly correlated with the severity of electrodiagnostic changes; in addition, there was a significant correlation between the thenar muscle major axis and the grasp power or Kapandji score. Taken together, these results revealed that thenar muscle atrophy did not affect patient-based assessments, including VAS and Q-DASH, but reflected electrodiagnostic results, particularly DML and severity. The results of the present study suggest that thenar muscle atrophy can be used to estimate the severity of carpal tunnel syndrome.

An update on addressing important peripheral nerve problems: challenges and potential solutions

From time to time it is thoughtful and productive to review a medical field and reflect upon what are the major issues that need to be addressed and what is being done to do so. This review article is not meant to be all-inclusive but rather focuses on four evolving areas in the field of peripheral nerve disorders and treatments: (1) nerve surgery under ultrasound guidance using a new ultra-minimally invasive thread technique; (2) evolving magnetic resonance imaging (MRI) and ultrasound imaging techniques that are helping to both diagnose and treat a variety of peripheral nerve problems including entrapment neuropathies, traumatic nerve injuries, and masses arising from nerves; (3) promoting recovery after nerve injury using electrical stimulation; and (4) developing animal models to reproduce a severe nerve injury (neurotmetic grade in continuity) that requires a surgical intervention and repair. In each area we first describe the current challenges and then discuss new and emerging techniques and approaches. It is our hope that this article will bring added attention and resources to help better address peripheral nerve problems that remain a challenge for both patients and physicians.

Carpal tunnel syndrome in inherited neuropathies: A retrospective survey

INTRODUCTION

This study evaluates carpal tunnel syndrome (CTS) symptom severity, functional status, and outcome of CTS therapies in patients with inherited neuropathies.

METHODS

Validated questionnaires were used to compare symptom severity and functional status in patients with and without a diagnosis of CTS and a diagnosis of an inherited neuropathy.

RESULTS

309 patients with inherited neuropathies participated in this study. The CTS symptom severity score (SSS) was found to be the most useful tool in assessing CTS severity in patients with inherited neuropathy. Splint therapy and surgery were associated with significant improvement in carpal tunnel symptoms as measured through the SSS.

DISCUSSION

This study provides insight into the assessment of CTS symptom severity and patient-reported outcomes to CTS therapy in individuals with inherited neuropathies. The SSS appears useful for evaluation of CTS symptoms and patient-reported outcomes following CTS interventions in individuals with inherited neuropathies. Muscle Nerve 57: 388-394, 2018.

Cost-Minimization Analysis of Open and Endoscopic Carpal Tunnel Release

BACKGROUND

Carpal tunnel release is the most common upper-limb surgical procedure performed annually in the U.S. There are 2 surgical methods of carpal tunnel release: open or endoscopic. Currently, there is no clear clinical or economic evidence supporting the use of one procedure over the other. We completed a cost-minimization analysis of open and endoscopic carpal tunnel release, testing the null hypothesis that there is no difference between the procedures in terms of cost.

METHODS

We conducted a retrospective review using a private-payer and Medicare Advantage database composed of 16 million patient records from 2007 to 2014. The cohort consisted of records with an ICD-9 (International Classification of Diseases, Ninth Revision) diagnosis of carpal tunnel syndrome and a CPT (Current Procedural Terminology) code for carpal tunnel release. Payer fees were used to define cost. We also assessed other associated costs of care, including those of electrodiagnostic studies and occupational therapy. Bivariate comparisons were performed using the chi-square test and the Student t test.

RESULTS

Data showed that 86% of the patients underwent open carpal tunnel release. Reimbursement fees for endoscopic release were significantly higher than for open release. Facility fees were responsible for most of the difference between the procedures in reimbursement: facility fees averaged $1,884 for endoscopic release compared with $1,080 for open release (p < 0.0001). Endoscopic release also demonstrated significantly higher physician fees than open release (an average of $555 compared with $428; p < 0.0001). Occupational therapy fees associated with endoscopic release were less than those associated with open release (an average of $237 per session compared with $272; p = 0.07). The total average annual reimbursement per patient for endoscopic release (facility, surgeon, and occupational therapy fees) was significantly higher than for open release ($2,602 compared with $1,751; p < 0.0001).

CONCLUSIONS

Our data showed that the total average fees per patient for endoscopic release were significantly higher than those for open release, although there currently is no strong evidence supporting better clinical outcomes of either technique.

CLINICAL RELEVANCE

Value-based health-care models that favor delivering high-quality care and improving patient health, while also minimizing costs, may favor open carpal tunnel release.

Preoperative evaluation of peripheral nerve injuries: What is the place for ultrasound?

OBJECTIVE

The purpose of this study was to evaluate the usefulness of ultrasound in the preoperative workup of peripheral nerve lesions and illustrate how nerve ultrasonography can be integrated in routine clinical and neurophysiological evaluation and in the management of focal peripheral nerve injuries. The diagnostic role and therapeutic implications of ultrasonography for different neuropathies are described.

METHODS

The authors analyzed the use of ultrasound in 119 entrapment, tumoral, posttraumatic, or postsurgical nerve injuries of limbs evaluated in 108 patients during 2013 and 2014. All patients were candidates for surgery, and in all cases the evaluation included clinical examination, electrodiagnostic studies (nerve conduction study and electromyography), and ultrasound nerve study.

Ultrasound was used to explore the nerve fascicular echotexture, continuity, and surrounding tissues. The maximum cross-sectional area (CSA) and the presence of epineurial hyperechogenicity or intraneural hyper- or hypoechogenicity, of anatomical anomalies, dynamic nerve dislocations, or compressions were recorded.

The concordance rate of neurophysiological and ultrasonographic data was analyzed, classifying ultrasound findings as confirming, contributive, or nonconfirming with respect to electrodiagnostic data. The correlation between maximum nerve CSA and neurophysiological severity degree in entrapment syndromes was statistically analyzed.

RESULTS

Ultrasonography confirmed electrodiagnostic findings in 36.1% of cases and showed a contributive role in the diagnosis and surgical planning in 53.8% of all cases; the findings were negative (“nonconfirming”) in only 10.1% of the patients. In 16% of cases, ultrasound was not only contributive, but had a key diagnostic role in the presence of doubtful electrodiagnostic findings. The contributive role differed according to etiology, being higher for tumors (100%) and for posttraumatic or postsurgical neuropathies (72.2%) than for entrapment neuropathies (43.8%).

CONCLUSIONS

Ultrasound is a powerful, noninvasive tool for the examination of peripheral nerve injuries, and can guide diagnosis of and surgical strategy for focal peripheral nerve injuries. It allows direct visualization of the cause and extent of nerve lesions and finds its place between electrodiagnostic tests and exploratory surgery. It can provide invaluable information, such as the presence and extent of a mass, scar compression, or neuromas. The authors recommend it as a complement to routine clinical and neurophysiological evaluation and as the first-line imaging modality for masses of suspected nerve origin.

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.

Carpal tunnel syndrome: Analyzing efficacy and utility of clinical tests and various diagnostic modalities

Background:

Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy, but not adequately studied in India.

Objectives:

To study clinical tests, nerve conduction studies (NCS), ultrasonography (USG), and magnetic resonance imaging (MRI) in diagnosing CTS.

Materials and Methods:

We diagnosed CTS in 54 patients (93 hands) out of 60 screened patients with symptoms compatible with CTS, including 19 control patients (23 hands). We conducted provocative tests and calculated Boston Carpal tunnel Questionnaire (BCTQ) symptom (S) and function (F) scores. NCS positive patients were classified into mild, mild-to-moderate, moderate, severe, and all-CTS groups. Median nerve anteroposterior, transverse, circumference (CIR), and cross-sectional area (CSA) at inlet (I), middle (M), and outlet (O) each was measured by USG in all patients. MRI was done in 26 patients (39 hands).

Results:

Phalen, hand elevation and pressure provocation tests had higher sensitivity, Tinel's test had higher specificity and tethered median nerve and tourniquet tests had low sensitivity and moderate specificity. USG had low sensitivity but high specificity, and MRI had moderate sensitivity. USG in patients compared to controls was significantly abnormal in CSA-I, CIR-I, and CSA-O. Significant correlation was found between BCTQ-S and NCS and BCTQ-S and CIR-O. CIR-M, CIR-O, CSA-M, and CSA-I had correlation with NCS. MRI was significant in moderate and in moderate + severe groups combined and associated pathologies were detected in 59% patients.

Conclusion:

NCS remain gold standard but USG and MRI help increase sensitivity and detect mass lesions amenable to surgery.

Peripheral nerve imaging

Disorders of peripheral nerve have been traditionally diagnosed and monitored using clinical and electrodiagnostic approaches. The last two decades have seen rapid development of both magnetic resonance imaging (MRI) and ultrasound imaging of peripheral nerve, such that these imaging modalities are increasingly invaluable to the diagnosis of patients with peripheral nerve disorders. Peripheral nerve imaging provides information which is supplementary to clinical and electrodiagnostic diagnosis. Both MRI and ultrasound have particular benefits in specific clinical circumstances and can be considered as complementary techniques. These technologic developments in peripheral nerve imaging will usher in an era of multimodality assessment of peripheral nerve disorders, with clinical evaluations supported by anatomic information from imaging, and functional information from electrodiagnostic studies. Such a multimodality approach will improve the accuracy and efficiency of patient care.

Accuracy of MRI in diagnosing peripheral nerve disease: a systematic review of the literature

OBJECTIVE

MRI is increasingly being used to evaluate extracranial peripheral nerve disease in clinical practice. The objective of this study was to systematically review the accuracy of MRI in distinguishing normal from abnormal extracranial peripheral nerves.

CONCLUSION

There is significant heterogeneity between studies investigating the accuracy of MRI. Studies have shown that nerve T2-weighted or STIR hyperintensity, nerve enlargement, and nerve flattening are associated with peripheral nerve disease.

STRUCTURAL CHANGES OF THE CARPAL TUNNEL, MEDIAN NERVE AND FLEXOR TENDONS IN MRI BEFORE AND AFTER ENDOSCOPIC CARPAL TUNNEL RELEASE

The purpose of this study is to investigate the structural changes of the carpal tunnel, median nerve, and flexor tendons in magnetic resonance imaging (MRI) before and after endoscopic carpal tunnel release (ECTR). We studied 36 hands undergoing ECTR. In MRI, the cross-sectional area of the carpal tunnel and the median nerve at the hamate and the pisiform levels were measured. The distance from the volar side of carpal bone to the median nerve or tendons and the volar displacement were measured. In post-operative MRI, the transverse carpal ligament could not be well delineated and the carpal tunnel was significantly enlarged both at the hamate and pisiform levels. The median nerve was enlarged at the hamate level. The median nerve and flexor tendons significantly moved to the volar side. The volar displacement of the median nerve and flexor digitorum superficialis in the long and ring fingers was greater than the other tendons.

Analyzing longitudinal data to characterize the accuracy of markers used to select treatment

With the increasing availability of detailed clinical information, there is optimism that treatment choices can be selectively directed to those individuals most likely to benefit. While standard clinical trials can establish whether a treatment appears to be effective on average, subsequent work is needed to determine whether there are identifiable subgroups of subjects for whom treatment is either particularly beneficial or harmful. Molecular assays and modern imaging technology now allow numerous candidate measures to be used as potential determinants of treatment choice. In this manuscript, we focus on novel measures of decision accuracy that reflect the treatment marker objective. Specifically, we define longitudinal individual-level potential outcomes (principal strata) that characterize patient outcomes under treated and untreated states. We propose generalizations of sensitivity and specificity that measure the accuracy with which a marker can distinguish those subjects who are expected to have a more favorable outcome under a specific treatment choice from those subjects who are expected to have a more favorable outcome under alternative treatment options. For quantitative markers, we propose principal receiver operating characteristic curves that display the full range of potential sensitivity and specificity. We use simulations to demonstrate the properties of proposed estimators, and we illustrate the methods using candidate neuroimaging and electrodiagnostic markers that could be used to select patients for carpal tunnel surgery.

Compression and entrapment neuropathies

Peripheral nerve entrapments are frequent. They usually appear in anatomical tunnels such as the carpal tunnel. Nerve compressions may be due to external pressure such as the fibular nerve at the fibular head. Malignant or benign tumors may also damage the nerve. For each nerve from the upper and lower limbs, detailed clinical, electrophysiological, imaging, and therapeutic aspects are described. In the upper limbs, carpal tunnel syndrome and ulnar neuropathy at the elbow are the most frequent manifestations; the radial nerve is less frequently involved. Other nerves may occasionally be damaged and these are described also. In the lower limbs, the fibular nerve is most frequently involved, usually at the fibular head by external compression. Other nerves may also be involved and are therefore described. The clinical and electrophysiological examination are very important for the diagnosis, but imaging is also of great use. Treatments available for each nerve disease are discussed.

Imaging of the peripheral nervous system

This chapter summarizes progress in the evaluation of peripheral nerve (PN) lesions and disorders by imaging techniques encompassing magnetic resonance imaging (MRI) and nerve ultrasound (US). Due to the radiation exposure and limited sensitivity in soft tissue contrast, computed-tomography (CT) plays no significant role in the diagnostic work-up of PN disorders. MRI and US are complementary techniques for the evaluation of peripheral nerves, each having particular advantages and disadvantages. Nerve injury induces intrinsic MRI signal alterations on T2-weighted sequences in degenerating or demyelinating nerve segments as well as in corresponding muscle groups exhibiting denervation which can be exploited diagnostically. Nerve US is based on changes in the nerve echotexture due to tumor formation or focal enlargement caused by entrapment or inflammation. Both MRI and US provide morphological information on the precise site and extent of nerve injury. While US has the advantage of easy accessibility, providing images with superior spatial resolution at low cost, MRI shows better soft tissue contrast and better image quality for deep-lying nerve structures since imaging is not hindered by bone. Recent advances have remarkably increased spatial resolution of both MRI and US making imaging indispensible for the elucidation of causes of nerve compression, peripheral nerve tumors, and focal inflammatory conditions. Both MRI and US further guide neurosurgical exploration and can simplify treatment. Importantly, imaging can reveal treatable conditions even in the absence of gross electrophysiological alterations, illustrating its increasing role in clinical practice. In experimental settings, novel molecular and cellular MRI contrast agents allow in-vivo assessment of nerve regeneration as well as monitoring of neuroinflammation. Depending on further clinical development, contrast-enhanced MRI has the potential to follow cellular responses over time in vivo and to overcome the current limitations of histological assessment of nerve afflictions. Further advances in contrast-enhanced US has the potential for developing into a tool for the assessment of nerve blood perfusion, paving the way for better assessments of ischemic neuropathies.

Magnetic resonance neurography of median neuropathies proximal to the carpal tunnel

This review provides magnetic resonance neurography (MRN) imaging appearances of median neuropathy proximal to the carpal tunnel. Carpal tunnel syndrome (CTS) and its imaging have been extensively described in the literature; however, there is a relative paucity of information on the MR imaging appearances of different pathologies of the median nerve proximal to the carpal tunnel.

Outcome prediction value of nerve conduction studies for endoscopic carpal tunnel surgery

OBJECTIVE

Carpal tunnel syndrome is the most common entrapment neuropathy. We explore the clinical use of nerve conduction study in the outcome prediction and preoperative selection for endoscopic carpal tunnel syndrome surgery.

METHODS

Sixty-seven patients with carpal tunnel syndrome were prospectively enrolled. Each patient's clinical symptomatic score at baseline and 3 months postsurgery was compared with nerve conduction study parameters of distal motor latency, motor amplitude, motor conduction velocity, distal sensory latency, sensory amplitude, and sensory conduction velocity. A statistical logistic regression model was used to ascertain outcomes.

RESULTS

Endoscopic surgery resulted in significant improvement for all four major symptoms pain, numbness, paresthesia, and weakness. From multivariate logistic regression, a shorter distal sensory latency is associated with a higher likelihood of a good outcome (P = 0.058; odds ratio, 0.912; 95% confidence interval, 0.828-1.0) only for paresthesia. The other factors were not found to be significant (all P > 0.10). The area under the curve (AUC) was 0.69 (95% confidence interval for AUC, 0.50-0.88). A cutoff of 6.0 ms or lower for sensory latency predicts for good outcome (in terms of paresthesia score) with the sensitivity/certainty of 84.6% and positive predictive value of 86.8%. A receiver operating characteristic analysis of baseline paresthesia score for good outcome of the paraesthesia domain showed that the AUC was 0.967 (95% confidence interval for AUC, 0-1.0). At a cutoff of baseline paraesthesia score of 4 or above, prediction for good outcome achieved a sensitivity of 87.2% and positive predictive value of 97.1%.

CONCLUSIONS

A shorter distal sensory latency is associated with a higher likelihood of a good outcome for paraesthesia. In addition, patients with baseline of 4 or above had correlated with better surgical outcome than those with less severe symptoms. Our data thus suggest that surgical benefit is best seen in patients with moderate symptoms, in combination with electrophysiological evidence of early demyelination, as a possible therapeutic window.

Carpal tunnel syndrome: a review of the recent literature

Carpal Tunnel Syndrome (CTS) remains a puzzling and disabling condition present in 3.8% of the general population. CTS is the most well-known and frequent form of median nerve entrapment, and accounts for 90% of all entrapment neuropathies. This review aims to provide an overview of this common condition, with an emphasis on the pathophysiology involved in CTS. The clinical presentation and risk factors associated with CTS are discussed in this paper. Also, the various methods of diagnosis are explored; including nerve conduction studies, ultrasound, and magnetic resonance imaging.

Carpal tunnel syndrome secondary to ganglion cyst in a child

Carpal tunnel syndrome is uncommon in children and is associated with an underlying etiology in the majority of cases. The diagnosis of the condition in childhood is dependent on a high degree of clinical suspicion, careful clinical examination, and judicious use of confirmatory investigations. The authors report a novel cause of carpal tunnel syndrome in a child, and discuss the investigation and management strategies in childhood carpal tunnel syndrome.

Combination of high-resolution and color Doppler ultrasound in diagnosis of carpal tunnel syndrome

BACKGROUND

Ultrasound has recently emerged as a diagnostic tool in carpal tunnel syndrome (CTS).

PURPOSE

To evaluate the utility of a combination of high-resolution and color Doppler ultrasound as an alternative to electrodiagnostic tests (EDT), in CTS diagnosis, and to define an ultrasonographic prediction model for CTS.

MATERIAL AND METHODS

A total of 85 patients with certain clinical diagnosis of CTS and 49 healthy controls were enrolled. High-resolution and color Doppler ultrasound were performed and the cross-sectional area (CSA), hypoechogenicity, and hypervascularity of the median nerve were evaluated. Receiver-operating characteristic curves were used to determine the optimal cut-off point of median nerve CSA in diagnosis of CTS. Multivariate logistic regression analysis was used to formulate a prediction model for CTS.

RESULTS

The optimal cut-off point of median CSA in wrist was 10.5 mm(2). Hypervascularity (OR = 37.95), hypoechogenicity (OR = 12.30), and high CSA (OR = 34.79) of median nerve were significantly (P < 0.001) higher in CTS patients than in controls. No significant difference was found between the sensitivity and specificity of EDT and any of the above indices in prediction of CTS. An ultrasonographic model for prediction of CTS, comprised hypervascularity and/or high CSA of median nerve, could predict the CTS probability between 87-99%. The sensitivity and specificity of this model (86% and 84%) was not different from EDT (80% and 84%).

CONCLUSION

A combination of high-resolution and color Doppler ultrasound can be used as a non-invasive alternative to EDT in diagnosis of CTS.

Is there Light at the End of the Tunnel? Controversies in the Diagnosis and Management of Carpal Tunnel Syndrome

Carpal tunnel syndrome is a common disorder responsible for considerable patient suffering and cost to health services. Despite extensive research, controversies still exist with regards to best practice in diagnosis, treatment, and service provision. Current best practise would support the use of history, examination and electro-diagnostic studies. The role for ultrasound scanning in diagnosis of carpal tunnel syndrome is yet to be proven. It appears magnetic resonance image scanning has a role where a rare cause for carpal tunnel syndrome may be suspected and also in the detailed reconstruction of the anatomy to aid endoscopic procedures. Treatment options can be surgical or non-surgical and patient choice will dictate the decision. For non-surgical interventions many options have been trialled but until now only steroid use, acupuncture, and splinting have shown discernable benefits. Open surgical decompression of the carpal tunnel appears to be more simple and cost-effective than minimally invasive interventions. For those patients who reject surgery, splinting, acupuncture, and steroid injection can play a role. Recent work looking at different service delivery options has shown some positive results in terms of decreasing patient waiting time for definitive treatment. However, no formal cost-effectiveness analysis has been published and concerns exist about the impact of a stream-lined service on surgical training. In this review, we look at the different diagnostic and treatment options for managing carpal tunnel syndrome. We then consider the different service delivery options and finally the cost-effectiveness evidence.

Current concepts of carpal tunnel syndrome: pathophysiology, treatment, and evaluation

The current concepts of carpal tunnel syndrome (CTS) with respect to its pathophysiology, treatment, and evaluation are discussed. With regard to the pathophysiology of idiopathic CTS, biomechanical studies to determine the kinematics of the flexor tendon, and the median nerve inside the carpal tunnel may provide valuable insights. Different degrees of excursion between the flexor tendons and the median nerve could cause strain and microdamage to the synovial tissue; this has been microscopically observed. A biomechanical approach for elucidating the events that trigger the development of CTS seems interesting; however, there are limitations to its applications. Endoscopic carpal tunnel release (ECTR) is a useful technique for achieving median nerve decompression. However, it is not considered superior to conventional open carpal tunnel release in terms of fast recovery of hand function. Unless the effect of inserting a cannula into the diseased carpal tunnel on the median nerve function is quantitatively elucidated, ECTR will not be regarded as a standard procedure for relieving the median nerve from chronic compression. The treatment of CTS should be evaluated on the basis of patient-oriented questionnaires as well as conventional instruments because these questionnaires have been validated and found to be highly responsive to the treatment. It should be noted that nerve conduction studies exclusively evaluate the function of the median nerve, whereas patient-oriented questionnaires take into account not only the symptoms of CTS but other accompanying pathologies as well, such as flexor tenosynovitis. In Japan, the number of CTS patients is expected to rise; this may be attributed to a general increase in the life-span of the Japanese and increase in the number of diabetic patients. Thus, more efforts should be directed toward elucidating the pathophysiology of so-called idiopathic CTS, so that new treatment strategies can be established for CTS of different pathologies.

Magnetic resonance neurography and diffusion tensor imaging: origins, history, and clinical impact of the first 50,000 cases with an assessment of efficacy and utility in a prospective 5000-patient study group

OBJECTIVE

Methods were invented that made it possible to image peripheral nerves in the body and to image neural tracts in the brain. The history, physical basis, and dyadic tensor concept underlying the methods are reviewed. Over a 15-year period, these techniques-magnetic resonance neurography (MRN) and diffusion tensor imaging-were deployed in the clinical and research community in more than 2500 published research reports and applied to approximately 50,000 patients. Within this group, approximately 5000 patients having MRN were carefully tracked on a prospective basis.

METHODS

A uniform Neurography imaging methodology was applied in the study group, and all images were reviewed and registered by referral source, clinical indication, efficacy of imaging, and quality. Various classes of image findings were identified and subjected to a variety of small targeted prospective outcome studies. Those findings demonstrated to be clinically significant were then tracked in the larger clinical volume data set.

RESULTS

MRN demonstrates mechanical distortion of nerves, hyperintensity consistent with nerve irritation, nerve swelling, discontinuity, relations of nerves to masses, and image features revealing distortion of nerves at entrapment points. These findings are often clinically relevant and warrant full consideration in the diagnostic process. They result in specific pathological diagnoses that are comparable to electrodiagnostic testing in clinical efficacy. A review of clinical outcome studies with diffusion tensor imaging also shows convincing utility.

CONCLUSION

MRN and diffusion tensor imaging neural tract imaging have been validated as indispensable clinical diagnostic methods that provide reliable anatomic pathological information. There is no alternative diagnostic method in many situations. With the elapsing of 15 years, tens of thousands of imaging studies, and thousands of publications, these methods should no longer be considered experimental.

Surgery versus non-surgical therapy for carpal tunnel syndrome: a randomised parallel-group trial

BACKGROUND

A previous randomised controlled trial reported greater efficacy of surgery than of splinting for patients with carpal tunnel syndrome. Our aim was to compare surgical versus multi-modality, non-surgical treatment for patients with carpal tunnel syndrome without denervation. We hypothesised that surgery would result in improved functional and symptom outcomes.

METHODS

In this parallel-group randomised controlled trial, we randomly assigned 116 patients from eight academic and private practice centres, using computer-generated random allocation stratified by site, to carpal tunnel surgery (n=57) or to a well-defined, non-surgical treatment (including hand therapy and ultrasound; n=59). The primary outcome was hand function measured by the Carpal Tunnel Syndrome Assessment Questionnaire (CTSAQ) at 12 months assessed by research personnel unaware of group assignment. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00032227.

FINDINGS

44 (77%) patients assigned to surgery underwent surgery. At 12 months, 101 (87%) completed follow-up and were analysed (49 of 57 assigned to surgery and 52 of 59 assigned to non-surgical treatment). Analyses showed a significant 12-month adjusted advantage for surgery in function (CTSAQ function score: Delta -0.40, 95% CI 0.11-0.70, p=0.0081) and symptoms (CTSAQ symptom score: 0.34, 0.02-0.65, p=0.0357). There were no clinically important adverse events and no surgical complications.

INTERPRETATION

Symptoms in both groups improved, but surgical treatment led to better outcome than did non-surgical treatment. However, the clinical relevance of this difference was modest. Overall, our study confirms that surgery is useful for patients with carpal tunnel syndrome without denervation.

FUNDING

NIH/NIAMS 5P60AR048093 and the Intramural Research Program of the NIH Clinical Center.

Magnetic resonance imaging of the peripheral nervous system

The diagnostic work up of patients with peripheral neuropathy largely depends on clinical and electrophysiological investigations. In contrast to disorders of the CNS, magnetic resonance imaging (MRI) has not been widely used as a diagnostic tool in the PNS except for detection of nerve compressing mass lesions. Normal nerves appear isointense to the surrounding tissue on T1- and T2-weighted (w) MRIs, but upon injury the nerves become hyperintense and thus visible on T2-w MRI. These signal alterations can be exploited to diagnose nerve damage in vivo and to follow regeneration. In patients with peripheral nerve disorders, MRI has been especially useful in detecting focal intrinsic and extrinsic nerve lesions and may reveal treatable conditions even in the absence of gross electrophysiological alterations. This clinical review provides practical guidelines on the performance of nerve imaging by MRI and will focus on focal lesions exemplified by case presentations.