Conus medullaris stroke. Does F wave predict return of ambulation?

Absent F wave in the stage of spinal shock has been described in cases of traumatic spinal cord injury. The role of F wave in predicting prognosis after conus medullaris infarct has not been described. We describe herein a middle aged-man with a conus medullaris infarct. Both tibial and peroneal F waves were absent on day 4. The left tibial F wave reappeared in the following study on day 18. All F waves reappeared on day 56 at which time the patient was still wheelchair bound. He regained walking on day 105. We hypothesize that reappearance of initially absent F waves post conus medullaris infarct is a good prognostic sign for the return of ambulation. The applicability of this observation requires further research. We also discuss clinical and diagnostic caveats in this case.