Fluoroscopy is performed, and the parallax is removed by placing the desired markers and catheter tip in the center of the fluoroscopic field.

Ensure the VB spinal processes are aligned halfway between the spinal pedicles (on A-plane).

Radiopaque markers attached to a plastic ruler are taped to the back of the patient after positioning the patient supine on operating table to help demarcate the vertebral bodies.

It should be positioned to the right of the spine so as not to overlap the spine or the aorta.

The lettering on the ruler is correlated with the VB, e.g., the letter ‘Q’ may be at T12 level. The angiography run performed will depict the radiopaque letter, and the artery at this level will therefore be identified as T12 (i.e., by the level) and documented. The reason for doing this is to eliminate any difficulties in identification during interpretation later.

We use a preprinted table, as shown in Table 8.2, for documentation of reference letter and angiography scene number at each level.

Prep and drape both femoral regions.

Gain access to the femoral artery using modified Seldinger technique (see Chap. 2 for details on access).

Immobilize a segment of the artery between the index and middle fingers.

Infiltrate the skin overlying the immobilized segment and underlying tissue with local anesthesia using 1% lidocaine with epinephrine.

Make a small stab incision in the anesthetized skin.

Immobilize the artery, and with the bevel of single-wall needle leading, puncture the artery at 45° through the previously created stab.

When blood emanates from the needle hub, stop and advance the provided wire into the needle hub and into the arterial lumen.

Retract the needle over the wire. Make sure to maintain control of the wire at all times.

Introduce the pre-assembled 4 Fr sheath with dilator over the wire into the artery.

Withdraw the wire and dilator leaving the sheath in the artery.

Cover the hub of the sheath with your thumb to prevent unnecessary blood loss.

Introduce a J wire (60–70 cm) into the sheath until it is in the artery well beyond the sheath.

Maintaining control of wire at all times, retract and completely withdraw the small sheath over the wire.

Compress the artery with the same hand which is holding onto the wire to prevent bleeding from the enlarged entrance wound.

Introduce the 5 Fr or larger sheath over the wire into the arterial lumen.

Retract and remove the wire when the sheath has been positioned in the artery.

Connect the hub of the sheath to a RHV which is attached to tubing with three-way stopcock and neonatal transducer to ensure the continuously running heparinized saline solution is at a rate of 30 ml/h. Make a wet connection so that no air bubbles enter the vascular system.

Secure the sheath by suturing it to the skin using 2–0 silk.

Prepare a Cobra catheter (AngioDynamics, Queensbury, NY). Other options when having difficulties are indicated shown in Table 8.3.

We do not connect the diagnostic catheter to a flush system, and perform hand injections for angiography due to the frequency of injections performed. A one-way stopcock may be interposed between the catheter and syringe to prevent excessive blood loss. Meticulous catheter hygiene is maintained to prevent blood clot formation in the catheter, or embolism.

Introduce the catheter into the sheath and advance over a glidewire.

Once the diagnostic catheter is in the desired location, e.g., in the descending aorta for studying the thoracolumbar region, remove the guidewire.

Usually, the catheter tip needs to be pointed slightly posteriorly and laterally to enter the ostium of the spinal artery. Advance and retract it rostrally and caudally to find the ostium.

When the ostium is engaged, inject a small amount of contrast to confirm. Additionally, you will note that the catheter tip ceases its bobbing movement with arterial pulsations, when it is in a vessel origin.

Perform angiography. We hand-inject the contrast. Do so at a gentle gradually increasing rate.

The scale with radiopaque markers placed at the side of the patient is used to label each artery.

Remember, for practical convenience, the intercostal artery is labeled by the vertebral body at the same level.

For efficiency, once an ostium is found, catheterized, and angiography completed, it is pulled down maintaining the tip’s position. It will jump into the ostium of the next (caudal) vessel. The catheter tip may need to be rotated slightly posteriorly for more inferior branches and laterally for more cranial branches. Systematically complete one side in this fashion then address the opposite side. However, if the ostium on the opposite side is unintentionally catheterized, do not relinquish it before performing angiography. The idea is to perform the procedure efficiently in terms of time and contrast used.

When an intercostal artery at the level of lesion is injected, it will demonstrate the osseous, epidural, and paraspinal extensions of the lesion.

If the procedure was diagnostic only, the patient is monitored for approx 2 h and then discharged if he/she remains asymptomatic.

Any inexplicable change in neurological examination should lead to thorough investigation including CT head and if indicated repeat angiography.

Also monitor the access site for pseudo-aneurysm, vessel occlusion, etc.

The patient should be ambulatory, able to void, and back to pre-procedure status at time of discharge.

Site of vascular access should be documented, so that in a future study, the contralateral side is used.

Any unusual aspect encountered during navigation including difficult vasculature and how it was addressed should be documented for future reference.