The S1 "Scotty dog": report of a technique for S1 transforaminal epidural steroid injection.

OBJECTIVE

To report a technique for needle placement by using the bony landmark of the "Scotty dog" on an oblique view for epidural injection of corticosteroid into the S1 foramina.

DESIGN

Brief report on a technique for S1 transforaminal epidural steroid injection.

SETTING

Academic multispecialty spine center.

PARTICIPANTS

Patients with L5 and S1 foraminal and paracentral disk herniation with concurrent L5-S1 radicular pain.

INTERVENTION: Fluoroscopically guided, contrast-enhanced L5 and S1 transforaminal epidural steroid injections (ESIs).

MAIN OUTCOME MEASURES: Not applicable.

RESULTS

The L5-S1 foramina can be visualized with 1 oblique (and usually caudally tilted) fluoroscopic view. An S1 Scotty dog can be visualized as an anatomic landmark for the guidance of the needle tip into the S1 foramen. While performing simultaneous L5 and S1 transforaminal ESIs, 1 view can be used to guide both needles into the foramen. Thus, the procedure can be completed in less time and potentially with less radiation exposure than if different views for each foramen were to be used.

CONCLUSIONS

Classic description of the S1 spinal nerve block uses an anteroposterior approach to the foramen. Looking for an S1 Scotty dog facilitates predictable visualization of the foramen, medial needle placement with epidural flow of contrast, and simultaneous visualization for needle placement to the L5 foramen.