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Carpal tunnel syndrome ( cts )us criteria

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Ultrasound of Carpel tunnel syndrome

Veröffentlicht in: Gesundheit & Medizin

Carpal tunnel syndrome ( cts )us criteria

  1. 1. Carpal Tunnel syndrome ( CTS( Ultrasound criteria Presented By DR Laith Fadhel
  2. 2. Introduction • Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy, affecting 9% of women, 6% of men and it is responsible for significant morbidity and occupational absence. Clinical assessment is used for initial diagnosis and nerve conduction (Nerve Conductive ) studies are currently the principal test used to confirm the diagnosis. There is now good evidence that US can be used as an alternative to NC studies to diagnose CTS. US can assess the anatomy of the median nerve and also identify pathology of the surrounding structures that may compress the nerve. US sensitivity has been reported to be as high as 80-90%.
  3. 3. Signs & symptoms • Paresthesia in the hand through the distribution of median nerve • Night paresthesia in the fingers / pain in the forearm and arm • Weakness and atrophy of thenar muscle • + Ve (Tinel's sign ) a sensation of tingling or pins and needles in the distal extremities of a limb when percussion in made over the site of an injured nerve • Phalen’s sign : reproduction of pain or paresthesia with flexion of the wrist for one minute or more
  4. 4. Etiology of CTS • The carpel tunnel is fibro- osseous space between the carpel bones and the flexor retinaculum . It contains the eight flexor digitorum tendons . The flexor pollicus longus , the median nerve • The etiology of CTS is primarily the encroachment on the median nerve , this can be due either a decrease in size of tunnel , or increase in the volume of tunnel content • The most recently described common cause of CTS is repetitive stress injury as in computer keyboard operators
  5. 5. Common Cases of CTS • Osseous causes of tunnel narrowing • Misalignment of carpel bones • Displaced fractures • Hypertrophic bone changes and callus formation • Increase content volume causes of tunnel narrowing • Tendon sheath enlargement (traumatic synovitis ) • Synovial proliferation ( RA ) • Hypertrophied muscle ( occupational ) • Increase fat ( obesity )
  6. 6. Imaging technique • Patient positioning / the forearm should rest comfortably and the wrist is in supination • In the transverse imaging plane the ulnar artery is the medial landmark of the carpel tunnel • Imaging must be performed with the transducer in plane perpendicular to the tendon surface to eliminate the anisotropic effect • The tunnel contains the flexor digitorum tendons which are hyper echoic • Anterior to the tendons is the median nerve • The median nerve has a characteristic appearance which differentiates it from the fibillar hyper echoic tendons • The nerve is hypo echoic with a hyper echoic borders and show multiple bright reflectors in the transverse imaging plane • The median nerve is rounded or oval in the proximal wrist and flattens progressively as it courses through the carpel tunnel • Within the tunnel the nerve is in intimate contact with the flexor retinaculum , its size remains constant but its shape is quite variable
  7. 7. Imaging technique • In the longitudinal imaging plane the never is demonstrated coursing parallel and superficial to the flexor digitorum tendons
  8. 8.   Ultrasound finding : Subjective criteria  Flattening of the nerve, especially at the level of the hamate bone  Volar bulging of the flexor retinaculum                                                    Enlargement of the median nerve as it enters the carpal tunnel        Large fluid or fat layer surrounding the tendons                                     Decreased mobility of the median nerve on flexion and extension  of the fingers   Objective criteria The mean cross sectional area of the median nerve is greater Than 10 mm squared at the pisiform bone level                                The flattening ratio of the nerve (transverse diameter divided by  AP diameter) is greater than 4:1 at the level of the hamate bone   Volar bulging of the flexor retinaculum is greater than 3.1 mm      
  9. 9. Flattening of the nerve, especially at the level of the  hamate bone
  10. 10. Volar bulging of the flexor retinaculum  Volar bulging of the flexor retinaculum is greater than 3.1 mm
  11. 11. Enlargement of the median nerve as it enters the carpal tunnel  The mean cross sectional area of the median nerve is greater Than 10 mm squared at the pisiform bone level
  12. 12. The flattening ratio of the nerve (transverse diameter divided by  AP diameter) is greater than 4:1 at the level of the hamate bone
  13. 13. Case study / 49 y female presented with paresthesia in RT hand with pain extended from RT arm down to the wrist , with miner complying within LT hand for 3 years duration Age : 49 years Gender : female Hospital : Baghdad .T.H Date of examination : 26-3-2015 Hand RT -LT Diagnostic Imaging Finding / Ultrasound finding : Subjective criteria Flattening of the nerve, especially at the level of the hamate bone ( RT – present ) ( LT – not ) Volar bulging of the flexor retinaculum ( RT – present ) ( LT – present ) Enlargement of the median nerve as it enters the carpal tunnel ( RT – present ) ( LT – present ) Large fluid or fat layer surrounding the tendons ( RT – not ) ( LT – not ) Decreased mobility of the median nerve on flexion and extension ( RT – present ) ( LT – not ) of the fingers, hand or wrist Objective criteria The mean cross sectional area of the median nerve is greater Than 10 mm squared at the pisiform bone level RT ( 10.2 ) mm² LT ( 11.2 ) mm² The flattening ratio of the nerve (transverse diameter divided by AP diameter) is greater than 4:1 at the level of the hamate bone RT ( 3.7 :1 ) LT ( 3.5:1 ) Volar bulging of the flexor retinaculum is greater than 3.1 mm RT ( 2.7 m ) LT ( 2.3 m)
  14. 14. Moderate degree Bilateral CTS more on the right side
  15. 15. RT hand / flatting of MN + decrease mobility
  16. 16. Volar bulging of FR / 2.7mm
  17. 17. Mean CS area of MN (10.2 mm2(
  18. 18. Flatting ratio of MN must be grater than (4:1) of Transverse :AP { 3.7:1{
  19. 19. LT hand / no flatting of MN + no decrease mobility
  20. 20. Volar bulging of FR / 2.3mm
  21. 21. Mean CS area of MN (11.2 mm2(
  22. 22. Flatting ratio of MN must be grater than (4:1) of Transverse :AP { 3.5:1{
  23. 23. Other things seen with ultrasound Of course evidence of CTS is not the only thing seen on the ultrasound scans of hand and wrist and a variety of other lesions may be seen in the surrounding tissues. The scanner can also be used to study other nerve lesions. Ganglion cysts appear as very hypo-echoic (dark) spaces, sometimes with internal subdivisions yet without any evidence of flow on Doppler imaging:
  24. 24. This lesion below, clearly seen at the base of the little finger as a soft, somewhat lobulated, swelling, extending into the proximal phalanx of the little finger... ...is probably a lipoma, showing as a fairly uniform, evenly speckled, slightly encapsulated structure on ultrasound, again without evidence of internal flow on Doppler imaging.