Entrapment neuropathies II: carpal tunnel syndrome

Diagnostic and Interventional US of the Wrist and Hand: Quadrant-based Approach

Diagnostic and interventional US of the wrist and hand can be challenging due to the small size and superficial location of structures and various disorders that need to be considered. A quadrant-based approach (volar, ulnar, dorsal, and radial) provides a rational method for performing a focused examination and joint positioning during both diagnostic imaging and intervention. Volar wrist disorders primarily involve the median nerve and the digital flexor system comprised of the flexor tendons and pulleys. The ulnar nerve and extensor carpi ulnaris tendon are chiefly responsible for ulnar-sided wrist pain. The differential diagnosis for dorsal-sided symptoms typically involves the extensor tendon compartments and includes distal intersection syndrome, extensor pollicis longus tear, and digital extensor apparatus injury. The soft-tissue ganglion is the most common abnormality in the dorsal wrist, typically associated with wrist ligaments or joint capsule. Radial-sided pain may be secondary to de Quervain tenosynovitis and must be differentiated from the more proximal intersection syndrome. US is an important tool for assessing the ulnar collateral ligament of the first metacarpophalangeal joint of the thumb and differentiating between displaced and nondisplaced tears, thereby influencing management. Despite the complexity of the anatomy and potential pathologic features within the wrist, a focused quadrant-based examination can permit the sonologist to focus on the structures of relevance. In conjunction with a systematic approach, this can aid in precise and efficient diagnostic scanning and intervention of the wrist and hand. ©RSNA, 2023 Supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Anatomical Variants of the Upper Limb Nerves: Clinical and Preoperative Relevance

Profound knowledge of nerve variations is essential for clinical practice. It is crucial for interpreting the large variability of a patient's clinical presentation and the different mechanisms of nerve injury. Awareness of nerve variations facilitates surgical safety and efficacy. Clinically significant anatomical variations can be classified into two main groups: variability in the course of the nerve and variability of structures surrounding the nerve. In this review article we focus on the most common nerve variants of the upper extremity and their clinical relevance.

High-resolution ultrasonography in carpal tunnel syndrome: role of ancillary criteria in diagnosis and response to steroid injection

OBJECTIVES

(1) Development and validation of a composite ultrasound score (cUSS) for the diagnosis of carpal tunnel syndrome (CTS). (2) To predict treatment response after local corticosteroid injection.

METHODS

Wrists of CTS patients and controls were evaluated with high-resolution ultrasound and cross-sectional area of median nerve at carpal tunnel inlet (CSAp) and outlet (CSAd) and bowing of flexor retinaculum (FRB), flexor tenosynovitis, and intraneural vascularity and echogenicity changes were noted. Patients were prospectively followed after ultrasound-guided corticosteroid injection.

RESULTS

We studied 479 wrists of 141 patients and 99 controls. Optimal cut-offs for diagnosing CTS were 9.5 mm² and 10.5 mm², respectively, for CSAp and CSAd. A cUSS consisting of the following parameters was developed: age, CSAp, CSAd, FRB, and flexor tenosynovitis and echogenicity changes. External validation of cUSS yielded sensitivity, specificity, and diagnostic accuracy of 91.7%, 87.1%, and 89.8%, respectively. Treatment responses from 88 injections (median duration of follow-up of 6 months) were available with satisfactory initial responses in 69.32% (61/88) and relapses in 30.86% (25/81). Median time to relapse was 2 months. Initial response was predicted by FRB (odds ratio (OR): 5.43, 95% confidence interval (CI): 1.45-20.3, p = 0.012). Relapse was predicted by age (hazard ratio (HR) 1.168, 95% CI: 1.076-1.268, p = 0.0002), male gender (HR: 8.1.02, 95% CI: 2.394-27.422, p = 0.0007), FRB, (HR: 46.982, 95% CI: 5.048-437.293, p = 0.0008), and higher body mass index (HR: 0.238, 95% CI: 0.064-0.892, p = 0.0332).

CONCLUSIONS

The developed cUSS has a diagnostic accuracy of 88% for diagnosing CTS. Ultrasound parameters could predict both initial treatment response and relapse.

KEY POINTS

• Anatomical ultrasound parameters in addition to nerve cross-sectional area is important for diagnosis of CTS. • A composite US score for diagnosis of CTS was developed with accuracy 88.6%. • Bowing of flexor retinaculum predicts short and long term response to local steroid injection.

The use of ultrasound in athletes

Ultrasound is being used by sports physicians in their daily practice to problem solve, but there is still a reluctance for some radiologists to embrace this technique. It has become the "stethoscope" of the sports physician as it is freely available to have in the office setting (Tok, et al. [1]). This has been made possible by advances in technology making it cheaper and more affordable. In the United Kingdom, ultrasound has been performed by sports physicians, rheumatologists, surgeons, physiotherapists, podiatrists, anaesthetists, neurologists and emergency care physicians. It has become a core area of the curriculum in some of these specialties. In athletes it not only provides confirmation of the diagnosis but leads to a better treatment algorithm and can be used to direct intervention. Radiologists need to be aware of its strengths and weaknesses even if they are not able to perform such examinations.

The Median Nerve at the Carpal Tunnel … and Elsewhere

The median nerve (MN) may be affected by various peripheral neuropathies, each of which may be categorized according to its cause, as either an extrinsic (due to an entrapment or a nerve compression) or an intrinsic (including neurogenic tumors) neuropathy. Entrapment neuropathies are characterized by alterations of the nerve function that are caused by mechanical or dynamic compression. It occurs because of anatomic constraints at specific locations including sites where the nerve courses through fibro-osseous or fibromuscular tunnels or penetrates a muscle. For the diagnosis of peripheral neuropathies, physicians traditionally relied primarily on clinical findings and electrodiagnostic testing with electromyography. However, if further doubt exists, clinicians may ask for an additional imaging evaluation.

Increased stiffness of median nerve in systemic sclerosis

Background

Systemic sclerosis can affect peripheral nerves, but the extent and the nature of this involvement are not well defined. The aim of this study is to compare the sonoelastrographic measurements of median nerves in systemic sclerosis (SSC), idiopathic carpal tunnel syndrome (CTS) and healthy individuals.

Methods

The clinical, electrophysiological and ultrasonographic assessments were done. Patients with SSC and CTS were assessed with nerve conduction studies. The measurements of cross sectional areas (CSA) were performed at psiform and forearm level from axial US images. The elastic ratio is the ratio of strain distribution in two selected region of interests (ROI) done via comparing the median nerve to flexor digitorum superfcialis tendon. The ROIs were fixed to 2 mm.

Results

The study was completed with 47 hands of 24 patients with SSC, 53 hands of 27 patients with CTS and 38 hands of health controls. The CSA of CTS group was significantly higher than systemic sclerosis and control groups. The elastic ratio at psiform level and forearm levels of systemic sclerosis group were significantly higher than the CTS and control groups.

Conclusion

Median nerves lose the elasticity while the CSA’s are in the normal range in patients with SSC. These results suggested that the increased peripheral nerve involvement in SSC is about the increased stiffness of the nerves.

Intraoperative Ultrasound for Peripheral Nerve Applications

Offering real-time, high-resolution images via intraoperative ultrasound is advantageous for a variety of peripheral nerve applications. To highlight the advantages of ultrasound, its extraoperative uses are reviewed. The current intraoperative uses, including nerve localization, real-time evaluation of peripheral nerve tumors, and implantation of leads for peripheral nerve stimulation, are reviewed. Although intraoperative peripheral nerve localization has been performed previously using guide wires and surgical dyes, the authors' approach using ultrasound-guided instrument clamps helps guide surgical dissection to the target nerve, which could lead to more timely operations and shorter incisions.

US of the Peripheral Nerves of the Upper Extremity: A Landmark Approach

Ultrasonography (US) has become a first-line modality for the evaluation of the peripheral nerves of the upper extremity. The benefits of US over magnetic resonance (MR) imaging include higher soft-tissue resolution, cost effectiveness, portability, real-time and dynamic imaging, and the ability to scan an entire extremity quickly and efficiently. US can be performed on patients who are not eligible for MR imaging. Metallic implant artifacts are usually not problematic. US has been shown to have equal specificity and greater sensitivity than MR imaging in the evaluation of peripheral nerves. Any abnormal findings can be easily compared with the contralateral side. The published literature has shown that US has demonstrated clinical utility in patients with suspected peripheral nerve disease by guiding diagnostic and therapeutic decisions as well as by confirming electrodiagnostic findings. Common indications for upper extremity peripheral nerve US are the evaluation for injury due to penetrating trauma, entrapment by scar tissue, and tumor. US of the upper extremity is most commonly performed to evaluate carpal and cubital tunnel syndrome. It is important for the radiologist or sonographer to have a detailed knowledge of anatomy and specific anatomic landmarks for each nerve to efficiently and accurately perform an examination. The goal of this article is to introduce readers to the basics of US of the peripheral nerves of the upper extremity with a focus on the median, ulnar, and radial nerves. Common sites of disease and the location of important anatomic landmarks will be reviewed.

Ultrasonography for Hand and Wrist Conditions

Ultrasonography facilitates dynamic, real-time evaluation of bones, joints, tendons, nerves, and vessels, making it an ideal imaging modality for hand and wrist conditions. Ultrasonography can depict masses and fluid collections, help locate radiolucent foreign bodies, characterize traumatic or overuse tendon or ligament pathology, and help evaluate compressive peripheral neuropathy and microvascular blood flow. Additionally, this modality improves the accuracy of therapeutic intra-articular or peritendinous injections and facilitates aspiration of fluid collections, such as ganglia.

Sonographic features of peripheral nerves at multiple sites in patients with diabetic polyneuropathy

OBJECTIVE

Diabetic polyneuropathy (DPN) is one of the major complications of diabetes mellitus. Ultrasound has been frequently used for evaluation of peripheral nerves. However, there are few studies that have evaluated multiple peripheral nerves in DPN. In this study, ultrasonographic features of multiple peripheral nerves in upper and lower extremities of DPN patients were investigated and compared with those of healthy controls.

METHODS

This study was a case-control study that enrolled 20 patients with confirmed diagnosis of DPN and 20 healthy controls. The ultrasonography was performed on the sural, tibial, fibular, sciatic, median, ulnar, radial, and musculocutaneous nerves. Nerve cross-sectional area (CSA) was measured at multiple points for each peripheral nerve. The CSAs were compared between DPN and control groups, and analyzed in relation to the clinical characteristics and electrophysiologic findings.

RESULTS

The CSAs were significantly larger in the DPN group for sural nerve, fibular nerve at the fibular head level, median nerve at the carpal tunnel and mid-humerus level, ulnar nerve at the cubital tunnel outlet and mid-humerus level, and radial nerve at the spiral groove. The CSAs of sural nerve, tibial nerve and median nerve were significantly correlated with electrophysiologic findings. The sural nerve CSA revealed significant correlation with HbA1c.

CONCLUSIONS

These results suggest that the ultrasonography can provide useful information in diagnosis and evaluation of DPN.

Sonography of Common Peripheral Nerve Disorders With Clinical Correlation

Sonography is now considered an effective method to evaluate peripheral nerves. Low cost, high resolution, the ability to image an entire limb in a short time, and dynamic assessment are several of the positive attributes of sonography. This article will review the normal appearance of peripheral nerves as shown with sonography. In addition, the most common applications for sonography of the peripheral nerves will be reviewed, which include entrapment neuropathies, intraneural ganglion cyst, nerve trauma, and peripheral nerve sheath tumors. Clinical information related to nerve disorders is also included, as it provides valuable information that can be obtained during sonographic examinations, increasing diagnostic accuracy.

Efficacy of high frequency ultrasound in postoperative evaluation of carpal tunnel syndrome treatment

Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy and a frequent cause of sick leave because of work-related hand overload. The main treatment is operation.

AIM

The aim of the study is to assess the usefulness of high frequency ultrasound in the postoperative evaluation of CTS treatment efficacy.

MATERIAL AND METHODS

Sixty-two patients (50 women and 12 men aged 28-70, mean age 55.2) underwent surgical treatment of CTS. Ultrasound examinations of the wrist in all carpal tunnel sufferers were performed 3 months after the procedure with the use of a high frequency broadband linear array transducer (6-18 MHz, using 18 MHz band) of MyLab 70/Esaote. On the basis of the collected data, the author has performed multiple analyses to confirm the usefulness of ultrasound imaging for postoperative evaluation of CTS treatment efficacy.

RESULTS

Among all 62 patients, 3 months after surgical median nerve decompression: in 40 patients, CTS symptoms subsided completely, and sonographic evaluation did not show median nerve entrapment signs; in 9 patients, CTS symptoms persisted or exacerbated, and ultrasound proved nerve compression revealing preserved flexor retinaculum fibers; in 13 patients, scar tissue symptoms occurred, and in 5 of them CTS did not subside completely (although ultrasound showed no signs of compression).

CONCLUSIONS

Ultrasound imaging with the use of a high frequency transducer is a valuable diagnostic tool for postoperative assessment of CTS treatment efficacy.

High-frequency ultrasound in carpal tunnel syndrome: assessment of patient eligibility for surgical treatment

Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy and a frequent cause of sick leaves because of work-related hand overload. That is why an early diagnosis and adequate treatment (conservative or surgical) are essential for optimal patient management.

Ultrasonography for nerve compression syndromes of the upper extremity

Nerve compression syndromes commonly involve the nerves in the upper extremity. High-resolution ultrasonography (US) can satisfactorily assess these nerves and may detect the morphological changes of the nerves. US can also reveal the causes of nerve compression when structural abnormalities or space-occupying lesions are present. The most common US finding of compression neuropathy is nerve swelling proximal to the compression site. This article reviews the normal anatomic location and US appearances of the median, ulnar, and radial nerves. Common nerve compression syndromes in the upper extremity and their US findings are also reviewed.

Assessment of the utility of ultrasonography with high-frequency transducers in the diagnosis of entrapment neuropathies

The primary aim of this paper was to assess the relevance of high-frequency ultra-sound examination in qualifying patients for either surgical or conservative treatment of peripheral entrapment neuropathies. The study was conducted in a group of 55 patients aged 7–83 (mean age 43.6), including 28 males and 27 females, who in 2009–2011 were referred to an ultrasound examination due to a clinical suspicion of entrapment neuropathies. For the purposes of the analysis, the patients were divided into four groups: carpal tunnel syndrome (1), ulnar nerve entrapment (2) (cubital tunnel syndrome and Guyon's canal syndrome), posterior interosseous nerve syndrome (3) and other entrapment neuropathies (4). The cases of isolated idiopathic carpal tunnel syndrome were excluded from the analysis. All patients underwent the interview, physical examination and ultrasound examination. Ultrasound examinations were performed with Esaote MyLab 50 and MyLab 60 systems using high-frequency broadband linear transducers: 6–18 MHz. Sixty-seven percent of patients (37 persons) underwent a neurophysiological test. Nerve echostructure, its hyperemia as well as nerve cross-sectional area or, in the case of small nerves, diameter were assessed in all patients. Furthermore, the following were assessed in individual groups: notch sign in group 1, nerve instability in a dynamic ultrasound examination in group 2, nerve angulation in a dynamic ultrasound examination and tenderness on nerve compression at the site of the visualized pathology in group 3. The analyses of the collected material were performed by means of descriptive statistics. The results of clinical and surgical verification were consistent with ultrasound findings in 96.4%. The results indicate that high-frequency ultrasonography is a valuable method in qualifying patients for various types of treatment of peripheral neuropathies resulting from compression.

Pitfalls in wrist and hand ultrasound

OBJECTIVE

The purpose of this article is to review a number of diagnostic pitfalls related to ultrasound evaluation of the hand and wrist. Such pitfalls relate to evaluation of ten-dons (extensor retinaculum, multiple tendon fascicles, tendon subluxation), inflammatory arthritis (incomplete evaluation, misinterpretation of erosions, failure to evaluate for enthesitis), carpal tunnel syndrome (inaccurate measurements, postoperative assessment), ulnar collateral ligament of the thumb (misinterpretation of the adductor aponeurosis and displaced tear), wrist ganglion cysts (incomplete evaluation and misdiagnosis), and muscle variants.

CONCLUSION

Although ultrasound has been shown to be an effective imaging method for assessment of many pathologic conditions of the wrist, knowledge of potential pitfalls is essential to avoid misdiagnosis and achieve high diagnostic accuracy.

Longitudinal design for sonographic measurement of median nerve swelling with controlled exposure to physical work using an animal model

In the study described here, we examined the feasibility of a longitudinal design to measure sonographically swelling of the median nerve caused by controlled exposure to a work task and to evaluate the relationship of changes in morphology to diagnostic standards. Fifteen macaques, Macaca fascicularis, pinched a lever in various wrist positions at a self-regulated pace (8 h/d, 5 d/wk, 18-20 wk). Nerve conduction velocity (NCV) and cross-sectional area (CSA) were measured every 2 wk from baseline through working and a 6-wk recovery. Trending across all subjects revealed that NCV slowed and CSA at the carpal tunnel increased in the working arm, whereas no changes were observed in CSA either at the forearm or for any measure in the non-working arm. There was a small negative correlation between NCV and CSA in the working arm. This study provides validation that swelling can be observed using a longitudinal design. Longitudinal human studies are needed to describe the trajectory of nerve swelling for early identification of median nerve pathology.

Carpal tunnel syndrome diagnosed using ultrasound as a first-line exam by the surgeon

This study evaluates the diagnostic value of ultrasound as a first-line exam in carpal tunnel syndrome. In 16 patients with carpal tunnel syndrome and 32 matched controls, evaluation of the median nerve was performed by the cross-sectional area at wrist level and wrist-forearm ratio. This study found statistically significant differences between patients and controls by both methods, and both showed high specificity and positive predictive values. Optimal cut-off values were identified at a 14 mm(2) cross-sectional area and a 1.6 wrist-forearm ratio. This study implies that ultrasound evaluation of the median nerve is a valuable tool as a first-line diagnostic test used by the surgeon for examination of patients with presumed carpal tunnel syndrome. Owing to the high positive predictive value of ultrasound, the need for referral to nerve conduction study may be limited.

Ultrasound for diagnosis of carpal tunnel syndrome: comparison of different methods to determine median nerve volume and value of power Doppler sonography

OBJECTIVE

To compare ultrasound measurement of median nerve cross-sectional area (CSA) at different anatomical landmarks and to assess the value of power Doppler signals within the median nerve for diagnosis of carpal tunnel syndrome (CTS).

METHODS

A prospective study of 135 consecutive patients with suspected CTS undergoing two visits within 3 months. A final diagnosis of CTS was established by clinical and electrophysiological findings. CSA was sonographically measured at five different levels at forearm and wrist; and CSA wrist to forearm ratios or differences were calculated. Intraneural power Doppler signals were semiquantitatively graded. Diagnostic values of different ultrasound methods were compared by receiver operating characteristic curves using SPSS.

RESULTS

CTS was diagnosed in 111 (45.5%) wrists; 84 (34.4%) had no CTS and 49 (20.1%) were possible CTS cases. Diagnostic values were comparable for all sonographic methods to determine median nerve swelling, with area under the curves ranging from 0.75 to 0.85. Thresholds of 9.8 and 13.8 mm(2) for the largest CSA of the median nerve yielded a sensitivity of 92% and a specificity of 92%. A power Doppler score of 2 or greater had a specificity of 90% for the diagnosis of CTS. Sonographic median nerve volumetry revealed a good reliability with an intraclass correlation coefficient of 0.90 (95% CI 0.79 to 0.95).

CONCLUSIONS

Sonographic assessment of median nerve swelling and vascularity allows for a reliable diagnosis of CTS. Determination of CSA at its maximal shape offers an easily reproducible tool for CTS classification in daily clinical practice.

T2-signal of ulnar nerve branches at the wrist in guyon's canal syndrome

OBJECTIVE

To evaluate T2-signal of high-resolution MRI in distal ulnar nerve branches at the wrist as diagnostic sign of guyon's-canal-syndrome (GCS).

MATERIALS AND METHODS

11 GCS patients confirmed by clinical/electrophysiological findings, and 20 wrists from 11 asymptomatic volunteers were prospectively included to undergo the following protocol: axial T2-weighted-fat-suppressed and T1-weighted-turbo-spin-echo-sequences (3T-MR-scanner, Magnetom/Verio/Siemens). Patients were examined in prone position with the arm extended and wrist placed in an 8-channel surface-array-coil. Nerve T2-signal was evaluated as contrast-to-noise-ratios (CNR) from proximal-to-distal in ulnar nerve trunk, its superficial/sensory and deep/motor branch. Distal motor-nerve-conduction (distal-motor-latency (dml)) to first dorsal-interosseus (IOD I) and abductor digiti minimi muscles was correlated with T2-signal. Approval by the institutional review-board and written informed consent was given by all participants.

RESULTS

In GCS, mean nerve T2-signal was strongly increased within the deep/motor branch (11.7±4.8 vs.controls:-5.3±2.4;p = 0.001) but clearly less and not significantly increased in ulnar nerve trunk (6.8±6.4vs.-7.4±2.5;p = 0.07) and superficial/sensory branch (-2.1±4.9vs.-9.7±2.9;p = 0.08). Median nerve T2-signal did not differ between patients and controls (-9.8±2.5vs.-6.7±4.2;p = 0.45). T2-signal of deep/motor branch correlated strongly with motor-conduction-velocity to IOD I in non-linear fashion (R(2) = -0.8;p<0.001). ROC-analysis revealed increased nerve T2-signal of the deep/motor branch to be a sign of excellent diagnostic performance (area-under-the-curve 0.94, 95% CI: 0.85-1.00; specificity 90%, sensitivity 89.5%).

CONCLUSIONS

Nerve T2-signal increase of distal ulnar nerve branches and in particular of the deep/motor branch is highly accurate for the diagnostic determination of GCS. Furthermore, for the first time it was found in nerve entrapment injury that T2-signal strongly correlates with electrical-conduction-velocity.

Ultrasound assessment on selected peripheral nerve pathologies. Part I: Entrapment neuropathies of the upper limb - excluding carpal tunnel syndrome

Ultrasound (US) is one of the methods for imaging entrapment neuropathies, post-traumatic changes to nerves, nerve tumors and postoperative complications to nerves. This type of examination is becoming more and more popular, not only for economic reasons, but also due to its value in making accurate diagnosis. It provides a very precise assessment of peripheral nerve trunk pathology – both in terms of morphology and localization. During examination there are several options available to the specialist: the making of a dynamic assessment, observation of pain radiation through the application of precise palpation and the comparison of resultant images with the contra lateral limb. Entrapment neuropathies of the upper limb are discussed in this study, with the omission of median nerve neuropathy at the level of the carpal canal, as extensive literature on this subject exists. The following pathologies are presented: pronator teres muscle syndrome, anterior interosseus nerve neuropathy, ulnar nerve groove syndrome and cubital tunnel syndrome, Guyon's canal syndrome, radial nerve neuropathy, posterior interosseous nerve neuropathy, Wartenberg's disease, suprascapular nerve neuropathy and thoracic outlet syndrome. Peripheral nerve examination technique has been presented in previous articles presenting information about peripheral nerve anatomy [Journal of Ultrasonography 2012; 12 (49): 120–163 – Normal and sonographic anatomy of selected peripheral nerves. Part I: Sonohistology and general principles of examination, following the example of the median nerve; Part II: Peripheral nerves of the upper limb; Part III: Peripheral nerves of the lower limb]. In this article potential compression sites of particular nerves are discussed, taking into account pathomechanisms of damage, including predisposing anatomical variants (accessory muscles). The parameters of ultrasound assessment have been established – echogenicity and echostructure, thickness (edema and related increase in the cross sectional area of the nerve trunk), vascularization and the reciprocal relationship with adjacent tissue.

Median nerve neuropathy in the forearm due to recurrence of anterior wrist ganglion that originates from the scaphotrapezial joint: Case Report

Background

Median nerve neuropathy caused by compression from a tumor in the forearm is rare. Cases with anterior wrist ganglion have high recurrence rates despite surgical treatment. Here, we report the recurrence of an anterior wrist ganglion that originated from the Scaphotrapezial joint due to incomplete resection and that caused median nerve neuropathy in the distal forearm.

Case presentation

A 47-year-old right-handed housewife noted the appearance of soft swelling on the volar aspect of her left distal forearm, and local resection surgery was performed twice at another hospital. One year after the last surgery, the swelling reappeared and was associated with numbness and pain in the radial volar aspect of the hand. Magnetic resonance imaging revealed that the multicystic lesion originated from the Scaphotrapezial joint and had expanded beyond the wrist. Exploration of the left median nerve showed that it was compressed by a large ovoid cystic lesion at the distal forearm near the proximal end of the carpal tunnel. We resected the cystic lesion to the Scaphotrapezial joint. Her symptoms disappeared 1 week after surgery, and complications or recurrent symptoms were absent 13 months after surgery.

Conclusions

A typical median nerve compression was caused by incomplete resection of an anterior wrist ganglion, which may have induced widening of the cyst. Cases with anterior wrist ganglion have high recurrence rates and require extra attention in their treatment.

[Vascular changes in severe carpal tunnel syndrome: a differential diagnosis of vasculitis]

Carpal tunnel syndrome may present with skin lesions. This may lead to a differential diagnosis with vasculitis. Sympathetic nervous system perivascular involvement and recurrent injuries secondary to sensory loss are probably part of the mechanism of injury. In this case, we also comment on the pathogenic role of persistent median artery associated with a bifid median nerve.