Marcio Fagundes: Today, I’ll demonstrate the technique to inject SpaceOAR® hydrogel between the prostate and the rectum via transparent needle approach. SpaceOAR® displaces the rectum away from the prostate and further reduces the dose of radiation to the rectum, minimizing risks of side effects. As I will demonstrate, the procedure can be easily done in the outpatient setting using local numbing of the skin, the subcutaneous tissue in the periprostatic area at the apex of the prostate, and patients tolerate the procedure very well with minimal discomfort. We administer four medications one hour in advance of the procedure. Ciprofloxacin or alternative broad-spectrum antibiotic for prophylaxis of infection. We use Hydrocodone with Acetaminophen and Diazepam to promote comfort and reduce anxiety.
We use Lidocaine and Prilocaine topical cream covered with a transparent dressing to anesthetize the superficial tissues of the perineum. We use Chlorhexidine and alcohol to reduce microbes in the surface of the perineum. A 20ml syringe filled with 20ml’s of 2% Lidocaine without epinephrine, buffered with 2ml’s of 8.4 sodium bicarbonate to provide local anesthesia of the subcutaneous tissues. We use a 22 gauge spinal needle, long enough to reach the prostate, but yet thin enough to minimize any local discomfort. Then we have the saline syringe for hydrodissection, sterile gloves, gauze pads, and drapes. Now, I’m cleansing the skin with the Chlorhexidine. Next, I’m inserting the ultrasound probe into the rectum. We will cover the ultrasound probe with a sterile drape. Now, we will begin the numbing procedure, inserting the needle about one or two centimeters above the ultrasound probe, injecting two or 3cc’s just beneath the skin.
Just before injecting Lidocaine, I will place negative pressure on the syringe to make sure that there is no blood flow into the syringe. I will then inject two or 3cc more right at the mid-depth between the surface and the prostate itself just to numb up the track of the needle used for the gel. The next step will be to numb up the right prostatic apex. The needle is advanced gently up to the apex, then another two to 3cc’s are injected at that level. Then I will pull back the needle about halfway and redirect it towards the patient’s left. Always going under the urethra. I don’t want to poke the urethra with the needle. I’m going to advanced it gradually to the left apex. Once I know the needle is at the apex, I will inject another two or 3cc’s at that level. Now, we see the needle advancing up against the capsule of the apex, and so we do the additional numbing at that level.
This assures us that the apex is numbed up on both sides. This is going to be used for placing the fiducial markers first, but it’s already the numbing that is necessary for the gel procedure. If we used about 3cc’s just under the skin, another three in the mid-depth and about three to four or so on the right apex and left apex, we have a total of some 12 or up to 15cc’s of Lidocaine total. Next, I will place the fiducials and prepare the SpaceOAR® device which will allow the Lidocaine to take full effect. Using a sterile technique, we will open the SpaceOAR® tray and lay it on a sterile field. Now, I will remove the end cap from the diluent syringe with the blue label. Attach the diluent syringe to the powder vial. Without depressing the plunger, pierced the vial seal by pushing the syringe into the vial cap until it is fully depressed. Inject a syringe contents into the vial.
The next step will be to shake the vial-syringe assembly until the powder is completely dissolved and set it aside at least one minute to help dissipate bubbles. Remove the accelerator syringe cap. Expel liquid as needed so that 5ml remain in the syringe. Pull back 1ml of air into the syringe to help avoid fluids from inadvertently entering the Y connector. With the syringe held upright and holding the syringe barrel, attach the accelerator syringe to the Y connector. Use caution not to depress the syringe plunger so as to avoid fluids entering the Y connector. You can see that the vial resting is now clear and most of the bubbles have dissipated. Invert the precursor syringe assembly and withdraw 5ml’s into the syringe. Avoid drawing bubbles into the syringe. Unscrew the diluent syringe from the powder vial, then pull back 1ml of air.
Holding the syringe upright, attach the accelerator syringe to the Y connector. Attach the syringe holder to the two syringe barrels. Carefully attach the plunger cap to the plungers of both syringes while holding the plungers to avoid dispensing solutions into the Y connector. Now I will attach the 18 gauge needle that is provided in the device tray to the saline syringe and prime the needle to make sure there is no air left in the needle itself. Now, we have the ultrasound probe positioned looking at the prostate on sagittal view and we have identified where the landing zone is for the hydrodissection needle. Now, I will insert the needle approximately one to two centimeters above the ultrasound probe. I angle the needle as needed to reach the perirectal fat between the anterior rectal wall and the prostate, slightly anterior to posterior angle.
Now, I gradually advance the needle past the rectourethralis muscle looking to reach the mid prostate level just posterior to the prostatic fascia. Once the needle has reached the perirectal fat, I will begin the hydrodissection. I will then switch the probe to axial view to verify that the hydrodissection is dissipating saline to both sides of the prostate and verify that the needle is positioned at midline. I inject a small puff of saline again to verify that the saline is dissipating. I will then advance the probe and make sure that I can see the base clearly and that the saline is dissipating all the way to the base of the prostate. I usually inject a total of four to 8cc’s of saline during the hydrodissection process.
Now, I will detach the saline syringe, keeping my hand on the ultrasound stepper absolutely still so I do not move the hydrodissection needle. Before attaching the SpaceOAR® syringe, advance the plungers to expel air only up to the top of the syringe. Do not allow the fluids to enter the Y connector as this could clog the device. Being careful to maintain the needle position, attach the SpaceOAR® system assembly to the 18 gauge needle. Recheck axial view for the needle tip position. Under ultrasound guidance in the sagittal view, use a smooth and continuous injection technique to dispense the SpaceOAR® hydrogel into the space between the prostatic fascia and the rectum. The entire injection content will be injected over approximately 10 seconds without stopping. Then withdraw the needle syringe assembly and discard the SpaceOAR® system.
I will then do a sagittal view inspection first to make sure the gel dispersed both left and right, and then change to axial view and inspect whether the gel had good dissipation from base to apex. The MRI scan reveals that the gel had very good dispersment from apex to base.