Magnetic resonance neurography studies of the median nerve before and after carpal tunnel decompression

Cudlip, Simon; Howe, Franklyn A.; Clifton, Andrew; Schwartz, Martin S.; Bell, B. Anthony

doi:10.3171/jns.2002.96.6.1046

Cited by 103 publications

(82 citation statements)

References 25 publications

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“…A decreased signal intensity may not only be interpreted as decreased intraneural edema (improvement), but also as decreased intraneural blood flow (deterioration). 8 Each patient completed the Boston carpal tunnel questionnaire, which consists of a symptom severity and a functional status sub-scale and is reproducible, internally consistent, valid and responsive to clinical change in patients with CTS. 32 Furthermore, the patient specific functional scale was administered, 33 which is a reliable and valid instrument to determine change in activities that are deemed difficult by the patient.…”

Section: Interventionmentioning

confidence: 99%

“…The signal intensity was expressed as a ratio to the flexor carpi ulnaris muscle signal at the radioulnar level to avoid variations in signal intensity encountered with the surface coil. 8 Signal intensity was calculated at three levels: (i) at the distal radioulnar joint where the pronator quadratus muscle was visible over the whole width of the radius (inlet of the carpal tunnel), (ii) at the center of the pisiform bone (mid-tunnel), and (iii) at the hook of hamate (outlet of the carpal tunnel). 9 Palmar bowing of the carpal ligament is also increased in CTS 29,30 and is considered an indirect measure of increased carpal tunnel pressure.…”

Section: Interventionmentioning

confidence: 99%

“…A reduction in signal intensity is interpreted as a reduction in intraneural edema. 8 To determine the signal intensity of the median nerve, a region of interest comprising the central area of the median nerve in the shape of an ellipse measuring 80% of the width and length of the median nerve was evaluated for its average gray level using a custom written MATLAB program (MathWorks, Natick, MA). Since the border of the median nerve is not always distinct on MRI scans, the use of an ellipse covering a predetermined proportion of the median nerve prevented the inclusion of extraneural signal.…”

Section: Interventionmentioning

confidence: 99%

“…4 In CTS, swelling of the median nerve has been identified intra-operatively, 5,6 with ultrasound imaging 7 and with conventional magnetic resonance imaging (MRI). 8,9 If present for prolonged periods, intraneural edema may lead to potentially irreversible fibrotic changes. 4 These fibrotic changes are present in patients with severe CTS.…”

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confidence: 99%

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Effect of splinting and exercise on intraneural edema of the median nerve in carpal tunnel syndrome—an MRI study to reveal therapeutic mechanisms

Schmid

Elliott

Strudwick

et al. 2012

Journal Orthopaedic Research

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Splinting and nerve and tendon gliding exercises are commonly used to treat carpal tunnel syndrome (CTS). It has been postulated that both modalities reduce intraneural edema. To test this hypothesis, 20 patients with mild to moderate CTS were randomly allocated to either night splinting or a home program of nerve and tendon gliding exercises. Magnetic resonance images of the wrist were taken at baseline, immediately after 10 min of splinting or exercise, and following 1 week of intervention. Primary outcome measures were signal intensity of the median nerve at the wrist as a measure of intraneural edema and palmar bowing of the carpal ligament. Secondary outcome measures were changes in symptom severity and function. Following 1 week of intervention, but not immediately after 10 min, signal intensity of the median nerve was reduced by $11% at the radioulnar level for both interventions (p ¼ 0.03). This was accompanied by a mild improvement in symptoms and function (p < 0.004). A similar reduction in signal intensity is not observed in patients who only receive advice to remain active. No changes in signal intensity were identified further distally (p > 0.28). Ligament bowing remained unchanged (p > 0.08). Intraneural edema reduction is a likely therapeutic mechanism of splinting and exercise. Keywords: MRI; nerve and tendon gliding exercises; splinting; carpal tunnel syndrome; neurodynamics Carpal tunnel syndrome (CTS) is a peripheral neuropathy at the level of the wrist. Despite considerable efforts, the pathophysiology of CTS is not yet fully understood. 1 There is however a well-established link between an elevated pressure in the carpal tunnel and the development of CTS. 2,3 When the pressure on a peripheral nerve is experimentally increased, a reduction of intraneural microcirculation occurs with subsequent breakdown of the blood nerve barrier and the formation of intraneural and extraneural edema. 4 In CTS, swelling of the median nerve has been identified intra-operatively, 5,6 with ultrasound imaging 7 and with conventional magnetic resonance imaging (MRI). 8,9 If present for prolonged periods, intraneural edema may lead to potentially irreversible fibrotic changes. 4 These fibrotic changes are present in patients with severe CTS. 9 Edema reduction to prevent progression to a fibrotic stage is therefore a plausible target in the management of patients with mild to moderate CTS.Besides advice, splinting and nerve and tendon gliding exercises are the most frequently performed noninvasive treatment modalities for CTS. 10 The beneficial effect of night splinting in a neutral wrist position is commonly attributed to the avoidance of end-range positions associated with high carpal tunnel pressures. 11,12 Maintenance of a neutral wrist position is believed to promote adequate blood circulation with a subsequent reduction of edema. 13 Although further research is required, recent systematic reviews indicate that conservative management with nerve and tendon gliding exercises may be beneficial for patie...

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Section: Interventionmentioning

confidence: 99%

Section: Interventionmentioning

confidence: 99%

Section: Interventionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Effect of splinting and exercise on intraneural edema of the median nerve in carpal tunnel syndrome—an MRI study to reveal therapeutic mechanisms

Schmid

Elliott

Strudwick

et al. 2012

Journal Orthopaedic Research

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“…It has been reported that the MR imaging technique is able to accurately and reliably visualize the three-dimensional (3D) geometries of the carpal tunnel and some of its contents to quantitatively measure the carpal tunnel [5,6]. Ablove et al [7] estimated the morphological changes in the carpal tunnel before and after carpal tunnel release surgery using MR images.…”

Section: Introductionmentioning

confidence: 99%

A Knowledge-Based Approach for Carpal Tunnel Segmentation from Magnetic Resonance Images

Chen

Wang²,

Lin³

et al. 2012

J Digit Imaging

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Carpal tunnel syndrome (CTS) has been reported as one of the most common peripheral neuropathies. Carpal tunnel segmentation from magnetic resonance (MR) images is important for the evaluation of CTS. To date, manual segmentation, which is time-consuming and operator dependent, remains the most common approach for the analysis of the carpal tunnel structure. Therefore, we propose a new knowledge-based method for automatic segmentation of the carpal tunnel from MR images. The proposed method first requires the segmentation of the carpal tunnel from the most proximally cross-sectional image. Three anatomical features of the carpal tunnel are detected by watershed and polygonal curve fitting algorithms to automatically initialize a deformable model as close to the carpal tunnel in the given image as possible. The model subsequently deforms toward the tunnel boundary based on image intensity information, shape bending degree, and the geometry constraints of the carpal tunnel. After the deformation process, the carpal tunnel in the most proximal image is segmented and subsequently applied to a contour propagation step to extract the tunnel contours sequentially from the remaining cross-sectional images. MR volumes from 15 subjects were included in the validation experiments. Compared with the ground truth of two experts, our method showed good agreement on tunnel segmentations by an average margin of error within 1 mm and dice similarity coefficient above 0.9.

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Splinting vs Surgery for Carpal Tunnel Syndrome

Menkes

2003

JAMA

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Magnetic resonance neurography studies of the median nerve before and after carpal tunnel decompression

Cited by 103 publications

References 25 publications

Effect of splinting and exercise on intraneural edema of the median nerve in carpal tunnel syndrome—an MRI study to reveal therapeutic mechanisms

Effect of splinting and exercise on intraneural edema of the median nerve in carpal tunnel syndrome—an MRI study to reveal therapeutic mechanisms

A Knowledge-Based Approach for Carpal Tunnel Segmentation from Magnetic Resonance Images

Splinting vs Surgery for Carpal Tunnel Syndrome

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