Management of Post-lumbar-operation Back Pain using Myofascial Trigger Point Injection: A Retrospective Study

Objectives: This study aimed to investigate the therapeutic effect of trigger point (TrP) injection of paravertebral muscle to control postoperative lumbar pain. Methods: The medical records of 46 patients who underwent lumbar surgery in our hospital between January 2013 and January 2020 were retrospectively analysed. The patients included in the study were divided into an observation group (n=26) and a control group (n=20) based on the certainty of their myofascial pain TrP diagnosis. The TrPs were found and injected with a 1:5 mixture of compound betamethasone/lidocaine (2 mL). The Visual Analogue Scale (VAS) scores and Patient Satisfaction Index (PSI) scores of the two groups were recorded before injection, on the day after injection, and one and two weeks after injection. The two groups’ postoperative bedridden time and analgesic medication treatment duration were calculated. All the scores were then compared. Results: The VAS scores of the observation group and the control group before injection were 7.00 ± 0.63 and 6.85 ± 0.59, respectively, and no significant difference was observed between the two groups (P>0.05). The VAS scores on the day and one and two weeks after injection were 2.65 ± 0.63, 3.46 ± 0.51, and 2.62 ± 0.50 in the observation group and 3.75 ± 0.44, 4.70 ± 0.47 and 4.95 ± 0.51 in the control group. Within the same group, the difference in patients at different time points was statistically significant (P<0.01), and the difference between the two groups at the same time point after injection was also statistically significant (P<0.01). The PSI score of the observation group was significantly lower than that of the control group (P<0.01). The bedridden time of the observation group was 2.71 ± 0.45 d, which was shorter than the bedridden time of the control group (4.42 ± 0.49 d; P<0.01). The duration of non-steroidal drug use was also shorter in the observation group than in the control group (P<0.01). Conclusion: Accurate injection of compound betamethasone/lidocaine mixture at the pain TrP can effectively control the early pain response after lumbar surgery. It is also beneficial to the early recovery of postoperative function and improves the patient’s satisfaction with the surgery.