Clinical application of ultrasound in thoracic medial branch block and thoracic cooled-radiofrequency ablation: Case report and literature review

Abstract

Introduction: Radiofrequency ablation is a procedure used to alleviate pain by destroying nerves with by radiofrequency-generated heat. Traditionally, radiofrequency ablation is preceded by diagnostic medial branch block injections, both guided by fluoroscopy. Fluoroscopic visualization of the superolateral aspect of the thoracic transverse process, where thoracic medial branch nerves occur, can be challenging due to anatomical complexities, especially in obese patients. We present a novel technique in which ultrasound was utilized in conjunction with fluoroscopy to perform medial branch block and radiofrequency ablation of the thoracic medial branch nerves.

Case report: First, two diagnostic thoracic medial branch nerve blocks were performed under ultrasound guidance. For the subsequent radiofrequency ablation, spinal needles were first advanced under ultrasound guidance to the target thoracic medial branch nerves. The position of those spinal needles was then used to guide the placement of cooled radiofrequency ablation probes using fluoroscopy. The patient reported 100% pain relief following the procedures.

Discussion: We found that the addition of ultrasound allowed us to overcome the challenge of visualizing the superolateral aspect of thoracic transverse process under fluoroscopy alone. Direct ultrasound visualization allowed us to accurately and safely perform a thoracic medial branch block and radiofrequency ablation in a patient with poor fluoroscopic anatomy, as demonstrated by the patient's complete pain relief after both medial branch block and radiofrequency ablation. We also theorize that our novel technique allows the provider to directly visualize the pleura, which could reduce the risk of severe pneumothorax associated with thoracic medial branch block and cooled radiofrequency ablation.

Keywords: Chronic pain; interventional pain management; obesity; pneumothorax.

Figure 1.

Anteroposterior (AP) fluoroscopy of the patient’s thorax prior to RFA.

Figure 2.

Ultrasound image demonstrating echogenic 22-gauge 80-mm needle advanced to the superior lateral aspect of the T2 transverse process (TP).

Figure 3.

Anteroposterior (AP) fluoroscopy of the patient’s thorax after ultrasound-guided placement of spinal needles at the superolateral aspects of the T2, T3, T4, and T5 transverse processes prior to placement of C-RFA probes. Spinal needles are indicated by the red * symbols.

Figure 4.

Anteroposterior (AP, left) and lateral view (right) fluoroscopy of the patient’s thorax demonstrating placement of spinal needles and C-RFA probes at the superolateral aspects of the T2, T3, T4, and T5 transverse processes. Spinal needles are indicated by the red * symbols, and C-RFA needles are indicated by blue * symbols. Only three C-RFA needles are depicted because our equipment only allows for three C-RFA probes to be placed at a time. C-RFA of the last medial branch nerve was performed separately.