Electrical stimulation prior to medial branch block of the same nerve

Does anyone know of a code used to report electrical stimulation of a nerve prior to a medial branch block of the same nerve? Our physician used a radiofrequency needle under fluoroscopic guidance to perform electrical stimulation of a nerve to reproduce a patient's low back pain in order to determine the correct nerve for steroid injection. I do know the branch block is CPT® 64493 but I cannot find a code for the electrical stimulation. I did find CPT® add-on code 95873 but this code is specific to chemodenervation and not nerve blockade.

It very well may be the electrical stimulation is considered bundled into the block since it was a diagnostic procedure prior to a therapeutic procedure at the same anatomical location. However, separate equipment and supplies were used for this portion of the case.

Thanks for your help and insight.

re: Electrical stimulation prior to medial branch block of the same nerve

RF is unlisted and I have not heard of it being reimbursed.