Ultrasound-guided Transforaminal Lumbar Epidural Injection Targeting The Dorsal Part Of Vertebral Body: A Clinical Feasibility Study

Part one: The feasibility study of viewing the dorsal part of lumbar vertebral body through paravertebral transverse oblique foraminal ultrasound scanningObject: To test the feasibility of viewing the dorsal part of lumbar vertebral body through paravertebral transverse oblique foraminal scanning.Methods: Ultrasound exploration was performed at the foraminal levels of L1/2-L5/S1 bilaterally using paravertebral transverse oblique foraminal scanning in50 patients with symptomatic lumbar disc herniation(SLDH) who satisfied the inclusion and exclusion criteria.Results: In 50 cases with SLDH, ultrasound exploration at a total of 500 foraminal levels were performed, the dorsal part of vertebral body was detected successfully in 420(84%). The successful rate of L1/2-L5/S1 level was 100%, 100%,100%, 96% and 24%, respectively.Conclusion: The dorsal part of vertebral body could be detected at the most of L1/2-L4/5 foraminal levels and a minority of L5/S1 levels when paravertebral transverse oblique foraminal ultrasound scanning used.Part two: The clinical validation study of ultrasound-guided transforaminal lumbar epidural injection targeting the dorsal part of vertebral bodyObject: To test the clinical feasibility of ultrasound-guided transforaminal lumbar epidural injection targeting the dorsal part of vertebral bodyMethods: In-plane ultrasound-guided TFLEIs targeting the dorsal part of vertebral body were performed for 60 patients with SLDH, then the placement of the needle tip and contrast flow pattern were checked by X-ray fluoroscopy. The pain relief and complications were also recorded.Results: Of the 60(2 at L3/4, 32 at L4/5, and 26 at L5/S1) plannedultrasound-guided TFLEIs, 40 procedures were performed eventually. L5/S1 foraminal access were deemed impossible in 20 cases, because the dorsal part of vertebral body could not be detected in those cases. 38 of 40 injections were successfully performed under ultrasound guidance, in which correct needle tip placement and successful ventral epidural contrast flow were confirmed by X-ray fluoroscopy. The L5/S1 foraminal access was failed in 2 cases whose scheduled needle trajectory was obstructed by iliac crest. The mean visual analogue score for LSRP of 38 patients decreased from 68.1 ± 8.2 before the injections to 23.6 ± 12.3 30 mins after the injections(p =0.001). No serious complications were observed, except for temporary exiting root nerve irritation during the puncture process in 3 cases.Conclusion: For any patient with SLDH who plans to receive a TFLEI as therapy, when the dorsal part of vertebral body at the targeted foraminal level can be detected by ultrasound, in-plane ultrasound-guided TFLEI targeting the dorsal part of vertebral body could be considered as an alternative. This technique is safe and feasible, but restricted at L5/S1 foraminal level.