Fig 1.
The experimental procedures for injection and endoscopy.
(a) Schematic diagram showing the probe position and needle direction for the erector spinae plane block. (b) Ultrasound image demonstrating needle placement and dye spread of the erector spinae plane block. (c) Schematic diagram representing the endoscope position in the paravertebral space. (d) Typical endoscopic image of the thoracic paravertebral space.
Table 1.
Comparison of dye staining at various spinal levels using 10 ml or 30 ml of injectate for erector spinae plane blocks.
Fig 2.
Endoscopic findings after erector spinae plane block.
(a) A stained SCTL was identified at the level of T5, but no paravertebral spread was observed after injection with 10 ml of dye. (b) A stained SCTL at the level of T5 was identified, and paravertebral spread was also observed after injection with 30 ml of dye. (c) Deep staining of the spinal nerve in the intervertebral foramen at the T5 level was onserved after injection with 30 ml of dye. (d) A spinal nerve at the T7 level was stained after injection with 30 ml of dye, but the amount of dye was minute. SCTL is the superior costotransverse ligament.
Fig 3.
Anatomical dissection findings after erector spinae plane block.
(a) Spread pattern of dye to the fascial layer of the external intercostal muscles after erector spinae plane block with 10 ml (right) and 30 ml (left) of dye. (b) Posterior vertebral bodies were removed. Using an injection of 10 ml (right) of dye, no paravertebral spread was observed. Using 30 ml (left) of dye, T5 and T6 spinal nerves in the intervertebral foraminal area were stained (asterisks), and epidural spread (arrows) was observed at the T5 level. Intercostal nerves were revealed laterally but were not stained (arrowheads).