This study evaluated the effects of tramadol incorporation into MMA on patient outcomes in spinal surgery. Notably, the median LOS was decreased by 1 day, which was a significant difference, in patients treated with MMA. Similar to the findings of this study, Walker et al. reported a reduction of 0.7 days in the LOS because of the introduction of the MMA for spinal surgery [6]. However, the regimen of MMA employed in the study by Walker et al. differed from that of this study because of the regular administration of NSAIDs, acetaminophen, muscle relaxants, and lidocaine topical patches and administration of additional oral narcotic analgesics according to pain levels [6]. Concerns regarding persistent opioid use after surgery include misuse, abuse, addiction, and diversion [12]. The MMA regimen employed in this study may help mitigate these risks by incorporating tramadol, which is a weaker opioid, rather than a stronger one. Additionally, decreasing the LOS in the hospital can improve financial, managerial, and clinical outcomes, as it reduces the cost of patient care and minimizes the risk of nosocomial infections [13]. Although not investigated in this study, these factors likely affected the results. Further research on these factors and patient outcomes is necessary.

The median NRS scores on POD 3 and 5 after the introduction of MMA were notably reduced. This may be partially attributed to the administration of a regular dose of tramadol after dinner on POD 2. Kupers et al. reported that multiple oral doses of tramadol at the time of the surgery provided effective analgesia on the day after herniectomy [14]. Similarly, Kumar et al. reported that administering tramadol before lumbar discectomy resulted in lower pain scores and lower doses of additional analgesics [15]. Altogether, these findings support the use of tramadol for the management of acute postoperative pain.

There were no notable differences in the number of patients who used PCA pumps before and after the introduction of MMA. Additionally, similar observations were made for the number of patients who discontinued PCA pumps during the study. These results indicate that the application of MMA did not alter the quantity of narcotic analgesics administered using the PCA pumps. Notably, previous studies have reported a reduction in the use of oral narcotic analgesics [6, 7], although the quantity of narcotic analgesics used with the PCA pump has not been specified. In our study, the use of narcotic analgesics did not decrease possibly because no oral narcotic analgesics were originally used. However, the use of additional analgesics decreased after MMA application, suggesting that appropriate pain management was achieved. To the best of our knowledge, this is the first study reporting the effects of administering MMA, including tramadol after spinal surgery. Herein, the postoperative pain was managed using tramadol, rather than oral narcotic analgesics. This suggests that tramadol is a viable option for post-spinal surgery pain management.

There are several limitations to this study. First, it is a retrospective study, and we were unable to fully align patient backgrounds using propensity score matching. Therefore, caution should be exercised when interpreting the results. However, propensity score matching before or at different caliper sizes (0.1 or 0.5) also reduced the primary endpoint of hospital LOS (both, p < 0.001, data not shown). Second, due to the short hospital stay and the limited number of postoperative blood draws, we were unable to obtain sufficient data to assess side effects. Third, due to the retrospective design of this study, it was not possible to obtain NRS scores for every patient. Additionally, there was a lack of consistency among the healthcare providers who measured the NRS scores, which may have led to variations in the assessments. Fourth, improvements in surgical techniques may have enhanced surgical accuracy and accelerated wound healing, potentially resulting in lower postoperative NRS scores and shorter hospital stays.

Even with these limitations in mind, the results obtained from this study are very important, as they may provide valuable insights for treatment selection and approaches in the clinical setting of MMA with tramadol. Future studies should employ a prospective design, establish appropriate criteria, and ensure comprehensive data collection to enhance the reliability of findings and assess treatment efficacy and side effects with greater precision.