Objective      To evaluate the diagnostic value of translumbar magnetic stimulation motor evoked potentials for functional defecation disorders (FDD).       Methods      Eighty cases of FDD in- and out-patients in our department from March 2010 to September 2011 were enrolled in the study. Another 30 healthy volunteers were recruited during the same period. The patients were 37 males and 43 females

with a mean age of 53.12±17.60 (ranging from 23 to 69) and a mean course of 8.28±6.14 years. While the normal control group included 13 males and 17 females

with a mean age

of 25.67±7.32 (ranging from 19 to 35). Anorectal motor evoked potentials (MEP) was recorded after translumbar magnetic stimulation (TMS) over bilaterally lumbar nerve root to observe the motor nerve conduction in external anal sphincter.       Results        The amplitude of magnetic stimulation-lumbar motor evoked potentials (MS-LMEP) in the external anal sphincter was 725.63 ± 178.23 μV (ranging from 400 to 1 100)

and the latency was 3.35±0.412 ms (ranging from 6 to 3.7) in normal control. The amplitude was decreased

and the latency was prolonged compared with those of normal control (P>0.05). But there was no significant difference in both sides between the 2 groups (

P

<

0.05)．      Conclusion        Translumbar magnetic stimulation motor evoked potentials have a significant value in the diagnosis of FDD.