Are dorsal ramus nerve blocks the solution to postoperative lumbar spine surgery pain?

Mark G. Williams, Brian Rigney, Ahmad Wafai, Andrew Walder


Background: Open lumbar spine surgery typically results in significant post-operative pain. Most pain protocols promote a multimodal approach aiming to reduce opiate requirements. This case-matched, prospective clinical study aims to establish the efficacy of dorsal ramus nerve root (DRN) blocks for post-operative analgesia.
Methods: We conducted a case-control observational, single centre, prospective study of 15 consecutive patients who had DRN block for a single-level lumbar discectomy or one/two-level lumbar spinal decompression, from Jan 2018 to Jun 2018. These were case matched with a field infiltration group. We analyse for differences in mean and maximum rest pain scores, opiate requirement, mobilisation status and length of stay (LoS).
Results: No differences were seen in pain scores in the first 24 hours post-operation for DRN block vs. field infiltration groups (2.8 vs. 2.7, P=0.90). No reduction in the morphine sulphate equivalents dosage requirement was seen in the DRN group (43.1±46.4 vs. 37.6±33.5, P=0.26). Similar proportions of patients mobilised early (P=1.0) and the mean LoS was 1.7 vs. 1.8 days (P=0.81).
Conclusions: Dorsal ramus nerve block is not superior to local anaesthetic field infiltration of surgical wound in minor one or two level lumbar spinal decompression surgery in terms of alleviating pain, reducing opiate requirements, or facilitating earlier mobilisation and discharge.