Files
Document type
ArticleVersion
Published versionPublication date
Publication license
Please use this identifier to cite or link to this item: https://hdl.handle.net/2445/225401
The Transverse Process as a Landmark for Estimating Dural SacDepth and Feasible Planes for Optimized ParamedianNeedle Insertions
Journal Title
Director/Tutor
Journal ISSN
Volume Title
Related resource
Abstract
Background: The skin-to-transverse process distance (st) correlates with the skin-to-dural sac depth (d) and may be used to estimate optimal angles for perpendicular needle insertion using the formula inverse cosine d/√(1 + d2), as outlined in free visual guides.
Objective: We aimed to analyze the relationship between the transverse process and dural sac depth at lumbar levels relevant to spinal anesthesia and to determine the range of planes where perpendicular paramedian needle insertion is feasible when midline access is not viable.
Methods: Ten ex vivo trunks were flexed using an abdominal support, and CT scans were performed. Correlations between the transverse process and dural sac depth were evaluated from L3 to S1. Perpendicular planes at the level of needle paths were examined at L3-L4 and L4-L5. Median path viability was assessed.
Results: The transverse process aligned with the dorsal dural sac at L3, the posterior third at L4, and the middle zone at L5 or S1. Median needle insertion was not viable in 20-30% of L4-L5 and L3-L4 levels, respectively. However, paramedian access was possible. The vertical range of viable paramedian planes was 8.7 ± 2.9 mm (L4-L5) and 7.9 ± 1.9 mm (L3-L4). Coronal reconstructions showed that the upper level of the transverse process correlates with the skin-perpendicular planes where insertion is likely to succeed.
Conclusion: Many elderly spines lack viable midline paths. The superior aspect of the transverse process serves as a useful landmark for estimating dural sac depth, calculating paramedian angles, and identifying the plane for successful perpendicular needle insertion.
Subject
Subject (English)
Citation
Citation
PUIGDELLÍVOL SÁNCHEZ, Anna, et al. The Transverse Process as a Landmark for Estimating Dural SacDepth and Feasible Planes for Optimized ParamedianNeedle Insertions. NeuroSci.. 2025. Vol. 6, num. 4. [consulted: 7 of June of 2026]. Available at: https://hdl.handle.net/2445/225401