LESI LESI Techniques and Approaches 2

Question 1

During transforaminal LESI, which fluoroscopic view is used to confirm the needle tip is in the posterior (not anterior) epidural space?

Accepted Answer

Lateral view confirming the needle tip is posterior to the posterior vertebral body line

Answer

The lateral fluoroscopic view allows the physician to confirm that the needle tip is posterior to the posterior vertebral body margin, ensuring correct epidural rather than anterior disc or vascular placement.

Question 2

The paramedian interlaminar approach to lumbar epidural injection differs from the midline approach primarily in that:

Accepted Answer

The needle is angled medially and cephalad, bypassing the spinous process

Answer

The paramedian approach angles the needle from a lateral starting point medially and cephalad, avoiding the spinous process and often encountering a thinner ligamentum flavum.

Question 3

An inadvertent subdural injection during LESI differs clinically from an intrathecal injection because:

Accepted Answer

It deposits injectate between the dura and arachnoid, not within the CSF

Answer

The subdural space lies between the dura mater and arachnoid mater; injected material does not freely mix with CSF, producing a variable and often delayed neurological picture distinct from true intrathecal injection.

Question 4

When performing a caudal epidural injection, the 'pop' or loss of resistance typically occurs as the needle passes through which structure?

Accepted Answer

The sacrococcygeal membrane covering the sacral hiatus

Answer

The sacrococcygeal membrane (homologue of the ligamentum flavum) covers the sacral hiatus; piercing it produces the characteristic 'pop' signaling entry into the sacral epidural canal.

Question 5

Which fluoroscopic view is most useful for identifying the sacral hiatus before performing a caudal epidural injection?

Accepted Answer

Lateral view

Answer

The lateral view clearly delineates the sacral hiatus, the sacrococcygeal junction, and the depth of the sacral canal, guiding correct needle angulation and depth.

LESI - Lumbar Epidural Steroid Injection Practice Test

LESI - Lumbar Epidural Steroid Injection Practice Test

LESI LESI Techniques and Approaches 2