Imaging Findings, Fluoroscopic Time, and Results of the Lumbosacral Selective Nerve Root Block: Focus on the L5 Nerve Root Block

Introduction Selective nerve root block (SNRB) is a valuable diagnostic and therapeutic tool. In some cases, intra-nerve root puncture is difficult and time-consuming, and radiation exposure time for the surgeon may be prolonged. The aim of this study is to examine the contrast findings, fluoroscopic time, and outcomes of SNRB. Methods A total of 139 cases of SNRB were included in the study. We investigated radiating pain presence, duration of fluoroscopic time, contrast types for nerve roots, and SNRB outcomes. Contrast patterns of nerve roots were categorized into three types, which were: type 1: the presence of contrast along the nerve roots; type 2: the presence of contrast within the intravertebral foramen but not in the nerve root; and type 3: the absence of both nerve root and intravertebral foramen contrast. Results The mean fluoroscopic time was 12.8 ± 15.3 seconds for type 1, 11.1 ± 8.9 seconds for type 2, and 23.6 ± 18.8 seconds for type 3. Statistically significant differences were found between the three groups (p = 0.007), and subsequent multiple comparisons showed significant differences between type 1 and type 2 (p = 0.010) and between type 2 and type 3 (p = 0.015). The visual analog scale (VAS) score before and 30 minutes after SNRB demonstrated a significant improvement in all patients. The mean change in VAS before and after nerve root block was 49.6 ± 21.7 mm for type 1 cases, 49.8 ± 25.2 mm for type 2 cases, and 37.8 ± 23.6 mm for type 3 cases, with no statistically significant difference between the three groups (p = 0.090). The proportion of patients with subjective symptomatic improvement before and after SNRB was 91.3% in type 1 cases, 88.5% in type 2 cases, and 85.7% in type 3 cases, with no statistically significant difference between the three groups (p = 0.641). Conclusions The above findings indicate that type 3 is beneficial for both diagnostic and therapeutic purposes.