Residents Learning Curve of Lumbar Transforaminal Epidural Steroid Injections

Aim: There is a paucity of literature on beginners’ training and on the connection between patient safety for transforaminal epidural steroid injections (TFESI). It is the aim of this study to retrospectively assess the learning curves and associated complications of neurosurgery residents previously never exposed to TFESI and to compare them to experienced board-certified faculty neurosurgeons (BCFN).

Methods: Procedure time in minutes (min), dose-area-product (DAP) in cGy*cm2, periprocedural observations and complications in n = 354 TFESI for radicular pain secondary to lumbar disc herniation or lumbar spinal stenosis were extracted from operative notes and the electronic infiltration logbook in the per-injection format. Learning curves for residents (n = 238) and BCFN (n = 116) TFESI in terms of procedure time and DAP were estimated using monotone regression.

Results: Residents TFESI procedure time and DAP reached BCFN level (4.7 minute and 140.2 Gy*cm2) after 67 and 68 cases, respectively. Residents TFESI were unsuccessful in 1.7%, mostly for severe obesity and hypertrophied facet joints, but no severe complications were noted. Obesity, however, did not result in increased procedure times or radiation exposure in general. Residents were faster and required less fluoroscopy in TFESI of the upper lumbar nerve roots than for L5 or S1 in particular.

Conclusion: The residents learning curve for TFESI in terms of procedure time and radiation exposure can be overcome safely after less than 70 TFESI. An outcome analysis correlating to the interventionalist’s training level would be worth investigating in future studies.