PURPOSE: Targeted botulinum neurotoxin A (Botox) injections and peripheral nerve blocks are frequently used to diagnose headache trigger points amenable to surgery. However, a direct comparison between the two has yet to be thoroughly explored. This study directly compares the diagnostic accuracy of peripheral nerve blocks vs. Botox for identification of headache trigger points.
METHODS: A retrospective chart review was performed on all patients who received diagnostic targeted Botox and/or peripheral nerve blocks who subsequently underwent headache surgery. Pertinent patient demographics, pain location, injection outcomes, and surgical outcomes (determined by a ≥50% reduction in headache characteristics) were collected. Measures of diagnostic accuracy were calculated, and the Fisher’s exact test was used to compare sensitivities across modalities.
RESULTS: Forty-seven patients undergoing 87 surgeries met inclusion criteria. While 96% of all patients had a ≥50% reduction in headache characteristics, the proportion of patients achieving this was not significantly different across the Botox or block groups (97% vs. 94%,respectively;p>0.05). Further, nerve block injections exhibited a higher sensitivity than Botox, although this was not significant (79.17%, 68.2%; p= 0.508). Notably, among paired data, Botox injections had a higher PPV compared to the nerve blocks (92% vs 83%, respectively).
CONCLUSION: Both targeted Botox injections and peripheral nerve blocks have enabled reliable detection of trigger points. Although Botox demonstrated a higher PPV than blocks, blocks have faster onset, reduced cost, and reduced visits needed for detection of trigger points. Considering both groups have comparable sensitivities, surgeon selection of either diagnostic modality is supported by this evidence.