Fig 1.
Sagittal view using the in-plane approach. Image courtesy from author’s database.
Fig 2.
Firstly, the target interspinous space was identified using sagittal view, then the probe was rotated 90° to transverse view and injection was performed with the out-of-plane approach. Image courtesy from author’s database.
Fig 3.
Sagittal ultrasound view obtained for Technique 1 approach.
(A) Original image obtained from sagittal probe placement. (B) The bony parts of the spine were identified from the hyperechoic rim reflected. ISS: interspinous space, ITS: intrathecal space, PAVB: posterior aspect of vertebral body, P: Pedicle, SP: spinous process. Image courtesy from author’s database, captured from USG screen.
Fig 4.
Transverse ultrasound view for Technique 2 approach.
(A) Original image obtained from transverse probe placement. (B) The bony parts of the spine were identified from the hyperechoic rim reflected. CAP: Caudal articular process, CP: Costal process, FV: Foramen of vertebra (bordered by orange line), ITS: Intrathecal space (area highlighted in yellow), MP: Mamilloarticular process, VB: vertebral body. Image courtesy from author’s database, captured from USG screen.
Fig 5.
Dye spreading in all three of cadavers after injection using Technique 2.
Intrathecal space dye spread was shown in orange circle. No dye spreading in erector muscles. Image courtesy from author’s database.
Fig 6.
Dye spreading in erector spine muscles in two of three cadavers with Technique 1.
Dye spread suggesting the unsuccessful intrathecal injection, no dye found intrathecal space shown in orange circle. Image courtesy from author’s database.
Fig 7.
Needle advancement and placement using Technique 1.
(A) Still image captured while performing needle advancement. Probe placement and needle insertion demonstrated in bottom-right corner of the picture. (B) Needle tip was visualized and advanced with real-time ultrasonography visualization with target of reaching the intrathecal space via interspinous space. ISS: Interspinous space; ITS: Intrathecal space; N: Needle path (augmented by yellow line); PAVB: Posterior aspect of vertebral body; P: Pedicle; SP: Spinous process. Image courtesy from author’s database, captured from USG screen.
Fig 8.
Needle advancement and placement using Technique 2.
(A) Still image captured while performing needle advancement. Probe placement and needle insertion demonstrated in bottom-right corner of the picture. (B) Needle tip was visualized and advanced with real-time ultrasonography visualization with target of reaching the intrathecal space after identifying interspinous space from the previous sagittal view. CAP: Caudal articular process, CP: Costal process, ITS: Intrathecal space (area highlighted in yellow), MP: Mamilloarticular process, N: Needle path (augmented by yellow line), VB: Vertebral body. Image courtesy from author’s database, captured from USG screen.