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Scarring Triangle (L5-S1) Technique

Dr. Gil Faclier on January 31, 2017 at 1:14 pm
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    • Gil FaclierDr. Gil Faclier
      Participant
      Joined: Feb 14, 2016
      Posts: 1
      #5267

      Dear Colleagues,
      What is the fluoro angle for insertion of the needle? Do u square up the 5/1 disc first. Is there a sequel to see contrast pattern?
      -Dr. Gil Faclier
      M.D

      • Gabor B RaczGabor B Racz
        Participant
        Joined: Mar 28, 2016
        Posts: 30
        #5268

        Dear Gil,
        Your questions are very practical and reasonable and take a couple of years to get to the present positon. It can be a bit of a struggle some times to find the posterior side of the neural foramen. The patient is in the prone position and I do not square the L5/ S1 end plates because the S1 foramen is more superior and I am trying to pass the X-ray beam through the ventral and dorsal foramina when the two just light up. I slowly rotate the C-arm in a cephalad direction until the foramina lights up. Rotate the beam slightly laterally to move S1 medially. Mark the S2 neural foramen with a pointer for the entry point of the needle. This provides me sufficient angle to have a good needle and subsequent catheter direction for ventral scarring triangle passage. Local anesthetic infiltration is followed by placement of the 18 gauge RX2 Coude needle curving down and aiming for the S1 foramen. If you aim laterally the catheter may go through the sacrum. The positioning sequence I just described allows for you to aim to the S1 posterior neural foramen, which is more medial than the ventral S1 Neural Foramen.
        In addition to curving the needle downwards, there is a tendency to overshoot and the needle tip may end up above or below the S1 foramen. If you end up above, then pull back and exaggerate the position by trying to be more vertical in the needle passage. If you end up below the S1 neural foramen following bony contact, rotate the needle tip 180 degrees and advance until the needle tip (on the X-ray) is at the neural foramen. Rotate 180 degrees and push the needle tip into the sacral canal, the tip of the needle will be parallel to the structures inside the sacral canal, so there is no danger of cutting nerves and vessels. Remove the stylet and replace with the second protruding stylet so you can rotate the needle 180 degrees and can advance it to the ventral sacral canal, but not be completely on bone. It is optional to put a small volume of contrast in the sacral epidural location at this point. On the lateral view you may see the upper end of the ventral S1 opening like a funnel where the catheter tends to hang up on it if you are ventral. To solve this, I run my nail down the Versa-Kath rapidly holding the catheter between the thumb and the index finger which puts a nice bend on the catheter. This bend is enough to not hang up on the sacral foramen, on the A/P view it may take you multiple passes to get to be above the disk, not lateral, not medially but between the arm pit of L5 nerve root and lateral to the S1 nerve. Getting to this spot will give you a very satisfactory feeling.Contrast injection is not easy as the dura is stuck to the posterior longitudinal ligament, the pressure is almost as much as you can push, which is absorbed in separating the tissue planes. It is important to look on the anterior/posterior and lateral views making sure that the injected Omnipaque 240 is not intravascular, subdural or subarachnoid. Every now and then I see venous runoff without the catheter being in the vein, but the aspirations are negative. Dye spread pattern first localized ventral epidural, second dye spread down towards S1, L5 slowly on the underside and then S2 even L4. When you see dye outside the bony canal you can be rest assured that the pressure concern of loculation is disappearing. The full 10 ml’s of contrast is injected and the next sequence is spreading over to the opposite side in a very similar pattern…..S1 S2 L5 L4. On the lateral view, there is a beautiful opening of the ventral epidural space. You may see dye spread in the posterior epidural space as well. The next sequence of injection is 150 units of human recombinant Hyaluronidase (Hylenex) in 10 ml’s of normal saline. I prefer to use 150 units of Hylenex or you can also use 750-1500 units of animal extract Hyaluronidase which facilitates the above outlined dye spread pattern. You must see fluid escaping from the spinal canal through the neural foramen. Next 10 ml’s of 0.2% Ropivacaine or .25% Bupivacaine and 40 mg’s of Triamcinolone, 2-3 ml test dose of local anesthetic and communicate with the patient for the ability to move lower extremities. Place the bacterial filter on the connector and wait 30 minutes until you infuse same or less volume of the Hypertonic Saline over 15 minutes and then two more times 6 – 8 hours apart. If the patient hurts, then stop and re-inject some local anesthetic to stop the pain caused by the infusion of the Hypertonic Saline.Sedation is mainly 1-2 mg’s of Midazolam and 25 – 50 micrograms of Fentanyl (age dependent).Clinical pearls; recovery of foot drop occurs sometimes rapidly in minutes from stretch injury of the nerve that are reversible. Similarly I have had inability to void reversed.The back pain that Dural Tug elicits is reversed in these patients for a very long time.Indication: Primarily L5 S1 radiculopathy, Back pain
        Note: Many patients have multiple pathologies such as spinal stenosis and DJD (Degenerative Joint Disease) that need multi-level treatments e.g. spinal stenotic segment needs to be opened up at the worst level with a transforaminal injection of a Versa-Kath epidural catheter. I.E. Double Catheters – The scarring triangle, even though it is limited in size to 1.1 ml on each side. The scar in most circumstances can spread which can only be reached with the Versa-Kath. So far I have seen this with S1 and S2, where opening up gets rid of back pain and have negative SLR but persistent S1 or S2 pain even in the presence of surgical fusion and micro discectomies. Remember, the RX2 Coude reduces the chance of needle tip cuts and injuries from intentional and unintentional movement of the sharp needle tip. The volumes of injected fluids for the transforaminal S1 injection is reduced to 5ml each – make sure there is LATERAL RUN OFF and no subdural spread from a surgical or idiopathic tear in the dura. You can only reduce the needle tip injuries but can have no influence on preexisting tears – only to diagnose it and treat it appropriately.

        Gabor B. Racz, M.D, FIPP
        Grover E. Murry Professor,
        Professor Emeritus Chair TTUHSC
        Ex-President World Institute of Pain

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