Table 3. The late follow-up Fisher’s exact test: the P value is 1.

ZCQ score	tcMEP better	tcMEP unchanged	Total
ZCQ improved	2	2	4
ZCQ unchanged	6	8	14
Total	8	10	18

ZCQ, Zurich Claudication Questionnaire; tcMEP, trans-cranial motor evoked potential.