Neuromodulation is the fundamental concept of delivering electrical charges to the nervous system by placing some form of stimulating electrode adjacent to the target neural tissue. Sacral neuromodulation (SNM) is a form of peripheral nerve stimulation that applies low-intensity chronic stimulation to asacral spinal nerve (usually S3). Available systems for SNM incorporate a basic final assembly of an electrode lead connected to an implanted pulse generator (IPG). To locate the sacral nerves during the procedure, knowledge of surface markings and the bony landmarks in the sacral region is very useful.

The procedure has been reported to fail in some cases.This study was used to answer this question by determining the reliability of certain anatomical landmarks.The needles were placed to each needle tip in connection to the upper part of the Sacral 3 foramen could be assessed.If the bone is visible, each foramen can be distinguished. For the upper part of the Sacral 3 foramen, the distance from the tip of each needle was assessed. The needle's entry into the foramen was also noted. From the tip of the coccyx

to the level of S3 bilaterally all of the dimensions were measured as well as from the middle ridge of the sacrum of the S3 lateral aspect to the foramina on either side and reported.The tip of the coccyx to the level of S3 (TC-S-S3) is 9.29±0.55and the middle ridge of the sacrum of the S3 lateral measurement (MSR-LS3)is2.31±0.08. In the female cadaver tip of the coccyx to the level of S3 (TC-S-S3) is 9.27±0.2and middle ridge of the sacrum of the S3 lateral measurement (MSR-LS3) is 2.15±0.07. In the male cadaver tip of the coccyx to the level of S3 (TC-S-S3) is 9.15±0.44and the middle ridge of the sacrum of the S3 lateral measurement (MSR-LS3) is 2.09 ±0.07.For in-office blind percutaneous nerve examination, a distance of 9 cm from the tip of the coccyx is an acceptable starting point (PNE). However, because coccyx length varies, caution should be exercised; also, sensory-motor response is required to validate appropriate positioning.

Keywords

Sacral neuromodulation, cadaveric study, Sacral nerves, surface markings, bony landmarks