Re: Percutaneous nephrolithotomy with and without retrograde pyelography: a randomized clinical trial.

St. Mark’s electrode used in the study has the distance between the stimuli and recording sites known in a region of difficult access for measuring. This would become the method more standardized and appropriate for pelvic floor, besides probably causing less discomfort than the transmuscular perineal route. These alternative methods for PNTML assessment might be useful in routine practice, mainly for intraoperative monitoring. Nevertheless it should be tested in further studies.