Article
Cross sectional area of the median nerve before revision carpal tunnel release – a cross sectional study
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Published: | June 9, 2017 |
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Objective: High- resolution ultrasound can be used for diagnosis of CTS with an accuracy that is on par to electrodiagnostic studies. Up to date there has been no investigation published that examined on a large patient cohort the median nerve in patients with recurrent or persistent symptoms. Reference and cutoff values are lacking. This study was done to provide reference values for detection of ongoing or recurrent compression in patients with recurring or persisting symptoms in carpal tunnel syndrome.
Methods: One hundred sixteen patients undergoing revision decompression of the median nerve at the carpal tunnel between January 2010 and October 2015 were studied retrospectively to determine the cross-sectional area of the median nerve at the wrist by the technique of neurosonography.
Results: In cases of insufficient primary release the mean cross-sectional area was 20.0 mm2 pre-op. In cases of scar or synovialitis the mean cross sectional area was 17.0 mm2 (significantly less, p=0.008). Compared to successfully operated patients with de-novo carpal tunnel syndrome (n=74), a cutoff value of 14.5mm2 yielded a sensitivity of 78% and a specificity of 97% to diagnose ongoing or recurrent compression in case of a typical clinical presentation.
Conclusion: For the first time we provide reference values in patients with recurring or persisting symptoms in carpal tunnel syndrome based on a large patient population. Ultrasound can aid in the evaluation of patients with entrapment neuropathy of the median nerve and recurring or persisting symptoms.