Thoracic Procedural Application
BACKGROUND: The thoracic zygapophysial joint is a common, but frequently overlooked, thoracic spinal pain generator. These struc-tures have been reported to account for up to 48% of chronic thoracic spinal pain. Although the innervation or the joint has been described, and diagnostic block techniques validated, sparse literature exists on thoracic RF medial branch neurotomy. A challenge, and obstacle to appropriate adoption of RF for this indication, is the extreme variability of the T5-8 medial branch locations. Many practitioners are appropriately reluctant to accept the increased risks of a thoracic procedtwe absent a reliable, safe, efficient, and effective technique. Large volume RF Iesions by an internally-cooled RF electrode have been studied. This device used with simple and safe technique will produce the necessary lesion size for reliable coagulation of thoracic medial branches including the T5-8 medial branches “floating” in the intertransverse space. The Nimbus MEE offers a comparable large volume lesion in a simplified, more economical electrode alternative.
T1-T12 Thoracic Medial Branch Neurotomy
1. Identify target by counting from T1 and T12.
2. Obtain segmental AP image and visualize the most superior lateral corner of the transverse process associated with target medial branch.
3. Consider slight ipsilateral oblique rotation of the C-arm (8-15 degrees), until you see the costotransverse joint lucency. In many cases this angle improves visualization/identification of superior lateral transverse process and directs the probe to thoracic anatomic safe zone medial to the pleural cavity, minimizing risk of pneumothorax.
4. Identify skin entry over inferior lateral aspect of transverse process slightly medial to costotransverse joint lucency.
5. Infiltrate skin and deep tissues with local anesthetic.
6. Gripping the central hub (colored), advance the cannula over bone starting at the inferior lateral aspect of the transverse process advancing cannula to superior lateral transverse process. This cannula navigation angle is very close to ” down the beam” with slight cranial angulation.
7. Gently touch bone.
8. Rotate C-arm to the contralateral side (15-20 degrees) until the targeted transverse process is visualized as elongated (Pinocchio view). The position of the cannula tip relative to the superior lateral corner of the transverse process is easily identified.
9. Position cannula tip at superior lateral corner of transverse process.
a. For T5-8 medial branches cautiously advance tip of cannula “sliding” it 3-5 mm cranial into the intertransverse space.
b. For T1-4, T9, T10 the cannula tip can stay on bone.
11. Rotate helical spin collar clockwise until fully advanced. A distinct tactile click will be appreciated with full engagement. Tines are deployed at this point.
12. Check AP and lateral x-ray views. The lateral view is useful only to rule out grossly ventral placement.
13. Motor stimulation at 2 Hz frequency at 1.5 – 2.0 volts is recommended to rule out ventral ramus activation (absent radicular fasciculations).
14. With tines fully deployed, inject local anesthetic, if desired.
15. Recommended heat cycle: 30-second ramp to 80 C maintained for 80 seconds.
16. Retract tines fully to remove cannula.