50th Annual Regional Anesthesiology and Acute Pain Medicine Meeting

Correlation of CT-Guided Planning with Real-Time Thoracic Epidural Placement: A Preliminary Experience

Christopher Deeble, MD; Hyo Jung Hong, MD, MBA; Rakesh V. Sondekoppam, MD

Introduction:

•Thoracic epidurals are known to provide excellent analgesia, yet a surgically congruent placement of epidural catheters remain challenging.

•The utility of pre-procedure CT analysis for predictive and real-time guidance of placement remains underutilized.

•We investigated whether pre-procedural CT measurements could predict loss of resistance (LOR) depth and needle trajectory angles during paramedian approach.

Methods:

•Pre-procedure thoracic CT scans of patients receiving thoracic epidurals were analyzed to determine the following:

1) estimated LOR depth range at intended level

2) potential needle trajectory angles in the sagittal plane, accounting for

paramedian approach (1 cm lateral, 1 cm caudad)

3) similar measurements for one vertebral level above

•A sagittal slice of the thoracic spine CT was centered at the intended level, followed by identifying the superior border of the spinous process, and finally the needle insertion point was marked 1cm caudad at the skin.

•To obtain a range of LOR, the distance from the skin to the edge of the interlaminar space just posterior of the spinal cord was measured, and a 15-degree angle medial redirection was accounted for.

•A protractor tool was then used to measure the needle insertion angles with respect to a tangent line at the skin insertion.

•Artificial intelligence (AI)-based image analysis was tested on a sample CT dataset for predictive and feedback-based trajectory planning.

Results:

•In three patients, epidural placement parameters closely matched CT predictions.

•In two patients with deeper LOR depths, actual placement parameters matched CT predictions for one vertebral space above the intended level (Table 1).

•Proof of concept AI analysis demonstrated feasibility of predictive needle trajectory and LOR depth based on the CT scans and 3D renderings (Figures 1 and 2).

Discussion:

•Pre-procedural CT analysis shows promise for predicting both thoracic epidural placement depth and optimal needle trajectory angles.

•When actual LOR depth exceeds predictions, the needle trajectory analysis can predict if the catheter may be one space above the intended level.

•This approach can be utilized to estimate the true thoracic level of placement if the depth and angle are significantly different than anticipated.

•This preliminary experience supports the potential utility of CT-guided planning and real-time angle tracking for improving thoracic epidural placement.

•Future development of AI-assisted analysis could further enhance this approach.

50th Annual Regional Anesthesiology and Acute Pain Medicine Meeting

CORRELATION OF CT-GUIDED PLANNING WITH REAL-TIME THORACIC EPIDURAL PLACEMENT: A PRELIMINARY EXPERIENCE

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