Clinical and MRI Factors Associated With Procedural Difficulty in Lumbar TFESI

The technical difficulty of transforaminal epidural steroid injection (TFESI) may be influenced by patient-related characteristics, the target spinal level, a history of lumbar surgery, the presence of spinal instrumentation, and degenerative or anatomical changes at the target level. The inability to predict procedural difficulty before the intervention may result in inefficient use of procedure-room time, fluoroscopy, and personnel resources. This prospective study will evaluate the associations between preprocedurally available clinical and magnetic resonance imaging (MRI) variables and objective measures of procedural difficulty. Objectives Primary Objective To determine the associations between preprocedural clinical and magnetic resonance imaging (MRI) characteristics and standardized TFESI procedural time, and to identify independent predictors of procedural duration. Secondary Objectives * To identify preprocedural factors associated with fluoroscopy time. * To identify factors associated with the number of fluoroscopic images acquired. * To identify factors associated with dose-area product/kerma-area product (DAP/KAP). * To identify factors associated with the number of major needle repositioning maneuvers and the need for additional skin puncture. * To evaluate differences in technical procedural outcomes among the L3-4, L4-5, and L5-S1 target levels. * If an adequate sample size and number of outcome events are available, to develop an exploratory TFESI Technical Difficulty Score. Hypotheses * Higher body mass index (BMI) and greater skin-to-target distance are associated with longer procedural and fluoroscopy times. * More severe foraminal stenosis, reduced intervertebral disc height, advanced disc degeneration, and spondylolisthesis are associated with greater technical difficulty. * A history of lumbar spine surgery and instrumentation at the target level are associated with less favorable technical procedural outcomes. * The target spinal level is independently associated with procedural difficulty after adjustment for other clinical and imaging variables.

Inclusion Criteria: * Age 18 years or older. * A clinical indication for unilateral, single-level lumbar transforaminal epidural steroid injection (TFESI) based on routine clinical assessment. * Planned TFESI at the L3-4 neural foramen for the L3 nerve root, the L4-5 neural foramen for the L4 nerve root, or the L5-S1 neural foramen for the L5 nerve root. * Availability of a clinically adequate lumbar magnetic resonance imaging (MRI) study obtained before the procedure. * Provision of written informed consent. Exclusion Criteria: * Lumbar MRI of insufficient quality for the required measurements or classifications. * Inability to complete the procedure for reasons unrelated to technical difficulty, such as equipment malfunction or an acute clinical event. * Known or suspected pregnancy. * Withdrawal of consent or withdrawal from the study.