[Carpal tunnel syndrome: sensory median-radial latency difference versus conduction studies in 1059 hands (668 cases)].
Between January 1989 and June 1996, 1,059 carpal tunnel syndrome hands (CTS) from 668 patients were studied. None had been previously operated and all had bilateral conduction studies; peripheral neuropathy was excluded. The patients were selected with sensory median/radial difference (MRD) > or = 1.0 ms that strongly supports electrodiagnosis of CTS (standard deviation > 6) after simultaneous stimulation on wrist and recording on thumb. Normal MRD were obtained in 125 hands with upper limit of normality = 0.43 ms (mean + 2SD). The age ranged from 17 to 83 years (mean 47.5) and 91.3% were female. MRD > or = 1.0 ms correlates in 95% with median distal motor latency > 4.25 ms (80 mm distance) and with median distal sensory latency to index finger > or = 3.01 ms, middle finger > or = 3.14 ms and ring finger > or = 3.26 ms, all of them 140 mm distance, antidromic and onset-measured. The results have brought new values for the limit of normality in our EMG laboratory since MRD > or = 1.0 ms is very sensitive for CTS diagnosis.
Departamento de Ciências Neurológicas, Faculdade de Medicina de São José do Rio Preto, Brasil. jaris@zaz.com.br
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JA
Kouyoumdjian
D000293:Adolescent; D000328:Adult; D000368:Aged; D002349:Carpal Tunnel Syndrome / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000502:physiology*; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology*; D011446:Prospective Studies; D012189:Retrospective Studies
Síndrome do túnel do carpo. Correlação da comparação de latência sensitiva mediano-radial com condução nervosa rotina em 1059 mãos (668 casos).