Search

Objective: The lumbar sympathetic trunk's (LST) distance to two anatomical landmarks, the costal process and medial margin of the psoas muscle, was assessed due to its use as landmarks for lumbar sympathetic blocks: the costal process for fluoroscopic guided techniques and the psoas major for CT- and MRI-guided techniques. Based on the measurements, we evaluate the trunk's visibility in MR and CT images for accurate positioning of the needle. Methods: A total of 54 cadavers embalmed with Thiel's method were investigated. The LST's distances to the psoas major's medial margin and to the base of the lumbar vertebrae's costal process were measured on the levels L2/3, L3/4 and L4/5. The measurements were compared to MR and CT images of 20 anonymous patients to identify the LST. Results: LST's mean distance to the psoas major was 0.3 mm at L2/3, 3.1 mm at L3/4 and 4.6 mm at L4/5. The mean distance to the costal process was 31 mm at L2/3, 34 mm at L3/4 and 32.6 mm at L4/5. In both MR and CT imaging, a structure could be determined as the LST correlating to the measurements with decreasing possible identification from cephalad to caudad levels. Conclusions: The costal process is a usable landmark for fluoroscopic guidance and the psoas major for CT- and MRI-guided techniques. The LST is clearly visible in MR and CT images, which gives both techniques a decisive advantage over fluoroscopy concerning the block of the LST due to a visible target. [ABSTRACT FROM AUTHOR]

Introduction: Image interpretation during ultrasound guided interscalene nerve blocks might be difficult and misleading due to rare anatomical variations of the sternocleidomastoid muscle. Case report: During a routine dissection, we found a cleidoatlanticus muscle, which originated lateral to the regular cleidomastoid portion of the sternocleidomastoid muscle. This muscle separated from the sternocleidomastoid muscle at level of the dorsally crossing omohyoid muscle to fuse with the levator scapulae muscle's origin at the transverse process of the atlas. Conclusion: As this muscle crosses at a level, where ultrasound guided interscalene blocks are performed, this unusual structure might lead to misinterpretation of the confusing ultrasound image, resulting in misguided needle positioning and consecutive inefficiency of the block technique. [ABSTRACT FROM AUTHOR]