Fig 1.
The final needle tip position in the modified interlaminar (MIL) approach is the ventral epidural space of the axillary portion of the exiting nerve root.
The filled circle indicates the position of the needle tip, while the white arrow indicates the ventral spread of the contrast medium.
Fig 2.
Advancement of the needle toward the pedicle of the target side.
The target point of A is the axillary portion of the left L4 root, and that of B is the axillary portion of the right L5 root.
Fig 3.
Demonstration of fluoroscopy location to create contralateral oblique (CLO) view during the modified interlaminar (MIL) approach.
The intensifier was rotated approximately 45 degrees contralateral to the target side. The red line indicates the needle direction. The dotted arrow indicates the direction of the X-ray beam.
Fig 4.
Advancement of the needle near the ventral interlaminar line (VILL).
Dotted oval shapes indicate the vertebral laminas and the dotted line indicates the VILL.
Fig 5.
After positioning the needle near the ventral interlaminar line (VILL) on contralateral oblique (CLO) view, the needle was verified to be oriented to the pedicle of the target side in fluoroscopic anteroposterior (AP) view.
Fig 5A and 5B are the same patient cases as in Fig 2A and 2B, respectively.
Fig 6.
When the needle passes the ventral interlaminar line (VILL), the loss of resistance (LOR) technique is initiated, and the epidural space is confirmed with contrast medium.
A syringe filled with contrast medium is shown on the screen.
Fig 7.
Contrast spread pattern in fluoroscopic anteroposterior (AP) view (A) and lateral view (B). The dotted line indicates contrast spread in fluoroscopic AP view. Note that the needle tip is located in the axillary portion of the right L5 nerve root. The white arrow indicates ventral spread of the contrast medium in fluoroscopic lateral view.
Table 1.
Demographic data and dominant pathologies of participants.
Table 2.
Procedure level and accessibility to the ventral epidural space.