Efficacy of surgeon-directed postoperative local injection with an analgesic mixture in posterior fusion surgery for adolescent idiopathic scoliosis

Background Severe postsurgical pain in posterior spinal fusion is common. Multimodality analgesia, including opioid-based patient-controlled analgesia (PCA), is commonly used, but opioid-related adverse events such as nausea and vomiting are sometimes a problem. We used a ropivacaine-epinephrine-dexamethasone mixture given as one-time local bilateral submyofascial injections at the operated levels added to conventional multimodality analgesia including PCA for postoperative pain control in one group of patients to confirm whether administration of this mixture reduced postoperative pain and opioid use status post posterior spinal fusion. Methods We retrospectively reviewed 67 consecutive patients who had undergone posterior fusion surgery for adolescent idiopathic scoliosis (AIS), 35 of whom were treated with conventional analgesia that consisted mainly of PCA (control group) and 32 of whom were treated with one-time submyofascial injections of a ropivacaine-epinephrine-dexamethasone mixture (submyofascial injection group) added to conventional multimodality analgesia. We compared postsurgical pain levels and the amount of opioid use over the first 48 h after surgery, as well as physical activity levels and adverse events 2 weeks after surgery. Results Postsurgical pain quantified by a numeric rating scale (1-10) in the submyofascial injection group was significantly lower than that in the control group. The amount of fentanyl use was significantly less in the submyofascial injection group at 24 h, 48 h, and all subsequent periods after surgery. In addition, Walking Recovery Time (WRT) defined as the number of days until the first event of ambulation was significantly less in the submyofascial injection group (3.3 d vs 4.1 d, P = 0.0007)). Laxative use was significantly less in the submyofascial injection group (0.3 times vs 1.3 times, P = 0.02). Conclusions One-time submyofascial injections at the operated levels with a ropivacaine-epinephrine-dexamethasone mixture after spinal fusion surgery reduced pain, opioid consumption, and opioid-related adverse events. This technique can contribute significantly to postoperative analgesia.