Performing Cavernous Nerve Stimulation in Rats to Measure Intracavernous Pressure
Transcription
In this procedure, make a 2-centimeter lower midline abdominal incision through the skin. Create a matching incision through the fascia along the linea alba to expose the bladder and the prostate. Use the retractors to achieve good exposure. Then, use cotton-tipped swabs to separate the prostate from the adipose tissue.
Adjust the retractors and complete the dissection until obtaining clear visualization of the MPG and CN, running on the dorsolateral aspect of the prostate. After locating the MPG and CN, carefully incise the fascia overlying the nerve, 2 to 5 millimeters distal to the MPG. Next, spread the tissue on each side of the nerve and underneath it to free a 4-millimeter-long portion, and then, slide a suture under the nerve.
Elevate the nerve slightly with the help of the suture to facilitate placement of the hooks of the bipolar electrode around the nerve. Let an assistant mix the two-component silicone glue with the tip of an insulin needle for 5 seconds. Dry the nerve, and apply the glue to the area around the hooks and the nerve. Keep the nerve elevated by pulling slightly on the electrode for approximately 1 minute to allow the glue to dry.
Afterwards, remove the retractors, except for the retractors on the right side, to avoid any pulling or twisting of the electrode. Subsequently, wet the exposed organs with saline, and lay gauze soaked in saline over the incision. In this procedure, restore visualization of the tunica albuginea using retractors. Make sure not to attach the retractors to the ischiocavernosus muscle, as it will distort the crus.
Next, attach the needle to PE-50 tubing and flush the tubing with heparinized saline before introducing it into the tunica albuginea. Keep the tunica albuginea stretched, and hold the overlying muscle distal to the point of insertion with your dominant hand. Then, hold the needle in your non-dominant hand and introduce it into the cavernous body. Flush the line to confirm correct placement in the cavernous bodies without a leak.
Insertion of the needle into the cavernous body for pressure recording constitutes a critical step. When deploying the needle into the crus, it is important that the crus is stretched and the needle is deployed parallel to its course.
Flush the tubing and press on the crus to test the line. Ensure that there are no leaks. After that, fasten the tubing to the table with tape to prevent accidental pulling on the line. Then, remove the retractors, set the parameters on a stimulator, and apply stimulation for 50 seconds with a minimum of a 1-minute rest between stimulations.
