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Background Targeted infiltrations to the lumbar spine are used to identify the correct scope for surgery in patients with chronic lumbar back pain (CLBP) and multi-segmental pathologies, where radiologic imaging and clinical presentation do not match. Conclusions from that method have so far been based on individual statements of pain relief. The main principle for the infiltrations is the assumption that by locally administering an analgesic agent to possible surgical target areas, the effect of surgery can be temporarily simulated. The aim was to investigate the use of rasterstereographic posture measurements to substantiate reported pain reduction after infiltrations. Methods In this case-control study (Level II), rasterstereography was performed on 57 patients and 28 reference subjects to evaluate changes in posture during 1 week of injections under fluoroscopic guidance and correlated with changes in the Numeric Pain Rating Scale (NRS). Statistical analysis was performed with SPSS (α = .05, two-sided) and presented in the form of box, scatter, and Bland-Altman plots. Results and Conclusion The CLBP patientsʼ trunk inclination (median 6°) and absolute lateral tilt were significantly increased (p < .01 each) compared to the reference group. No significant difference was observed for trunk length, kyphotic/lordotic angle, or lateral deviation. During infiltration, no significant difference in posture could be observed. A subgroup analysis of patients reporting the highest pain improvement indicated no significant difference. No correlation was observed with pain improvement reported by the patients during injections. Subsequent rasterstereography does not seem to be able to verify results of injections in the diagnostics of lumbar spine pathologies, as patientsʼ reported pain relief does not correlate with a relevant alteration in posture. The short-term effect of the targeted infiltrations may not suffice to change false posture being developed over years.