General evaluation

This study aimed to compare the efficacy of ultrasound-guided erector spinae plane block (ESPB) with that of wound infiltration (WI) for postoperative analgesia in lumbar spinal surgeries involving instrumentation. Our findings demonstrate that ESPB is very effective in providing postoperative pain relief because it lowered the time it takes to rescue analgesia and lowered total opioid consumption. These results are in line with those of previous studies, such as those by Yayik et al. and Gişi et al., which reported the effectiveness of ESPB in various types of spinal surgeries​ [5, 7, 19, 20]. These findings underscore the potential advantages of ESPB in managing postoperative pain, particularly in complex surgical settings where prolonged pain relief is crucial.

Analgesic efficacy

The primary outcome, postoperative pain intensity measured by the visual analog scale (VAS), revealed no significant differences between ESPB and WI at any postoperative time point (30 min, 1 h, 2 h, 4 h, 8 h, 12 h, or 24 h). These results are consistent with those of prior studies, such as those of Forero et al. (2016), who demonstrated that ESPB offers effective analgesia comparable to traditional infiltration methods in thoracic and abdominal surgeries [5]. Similarly, Chin et al. (2017) reported no significant difference in VAS scores between ESPB and alternative regional anesthesia techniques in hip surgery [7]. Despite the comparable VAS scores, the clinical implications are significant, as ESPB's ability to provide prolonged analgesia and reduce the need for rescue analgesia offers a clear advantage in postoperative pain management.

In addition to VAS scores, the literature supports the versatility and reliability of ESPB as a regional anesthesia technique across different surgical contexts. For example, studies by Chiraya et al. (2023) and Ueshima et al. (2019) have shown that ESPB significantly reduces opioid requirements in thoracolumbar and lumbar spinal surgeries, respectively, which aligns with our findings of reduced tramadol consumption​ [21, 22]. The reduction in opioid use, even without significant changes in VAS scores, suggests that ESPB may offer benefits beyond simple pain relief, potentially enhancing overall patient recovery and satisfaction.

Time to first rescue analgesia

The time to first request for rescue analgesia was significantly longer in the ESPB group than in the WI group (3.40 ± 3.00 h vs. 1.85 ± 2.60 h, p = 0.045). This finding indicates that ESPB provides a more prolonged analgesic effect, which can be advantageous in minimizing the need for additional analgesic interventions and enhancing patient comfort during the immediate postoperative period. Tulgar et al. (2018) highlighted the extended duration of analgesia associated with ESPB due to the distribution of local anesthetics in the paravertebral space [8]. The extended analgesic effect of ESPB not only enhances patient satisfaction but also reduces the workload of healthcare providers.

The prolonged duration before the need for rescue analgesia is clinically significant, particularly within multimodal analgesia strategies. Prolonged analgesia can contribute to reduced overall opioid and analgesic consumption, thereby mitigating the risk of adverse effects and promoting faster recovery. This finding is particularly relevant given the current opioid crisis, where reducing opioid consumption is a critical component of postoperative pain management.

Opioid consumption

A significant reduction in total tramadol consumption was observed in the ESPB group compared with the WI group (50 ± 60.00 mg vs. 100 ± 75.00 mg, p = 0.010). This opioid-sparing effect is clinically important, as it minimizes the incidence of opioid-related side effects, including nausea, vomiting, pruritus, and respiratory depression, which are major concerns in postoperative care. The opioid-sparing effect of ESPB has been well documented in the literature. For example, Ueshima and Otake (2017) reported significantly lower postoperative opioid requirements with ESPB in pneumothorax surgery [6].

Similarly, Wang et al. (2019) reported that, compared with WI, ESPB reduced perioperative opioid consumption in thoracotomy patients, which supports our findings. The reduction in opioid use is particularly significant given the current opioid crisis, where minimizing opioid consumption is a key objective in postoperative pain management [23].

The finding that VAS scores were not significantly different between the ESPB and wound infiltration groups, despite ESPB reducing opioid consumption and prolonging analgesia, is crucial. This can be explained by the following:

1.

Mechanism of ESPB: ESPB works by providing a wider range of analgesia than wound infiltration, covering multiple dermatomes. This could lead to more effective background pain control, even though the immediate VAS scores reflect a similar level of pain perception in both groups at discrete time points.

2.

Opioid-sparing effect: ESPB's ability to reduce opioid consumption is a significant advantage. Reduced opioid use could prevent opioid-induced side effects like nausea and vomiting, which are not directly measured by VAS but significantly impact patient comfort and recovery. This opioid-sparing effect, despite similar pain scores, may account for the enhanced patient recovery and prolonged analgesic effect without the need for as many rescue analgesics.

3.

Prolonged analgesic duration: The longer-lasting analgesia observed with ESPB means that patients are likely experiencing less breakthrough pain and fewer fluctuations in pain intensity over time. Even if the VAS scores are not significantly different, the quality of pain control could be superior with ESPB due to fewer analgesic interventions being necessary throughout the postoperative period.

4.

Patient satisfaction and clinical outcomes: Although VAS scores are important for measuring pain intensity, the reduction in opioid consumption and need for rescue analgesics may enhance overall patient satisfaction and recovery experience. This is a key aspect of postoperative care, where multimodal pain strategies, such as ESPB, can offer benefits that go beyond what is captured by VAS alone.

Postoperative nausea and vomiting (PONV)

While the incidence of PONV was greater in the WI group, the difference did not reach statistical significance (0.50 ± 0.75 vs. 0.25 ± 0.70, p = 0.095). Nevertheless, the trend toward reduced PONV in the ESPB group could be attributed to lower opioid consumption, as noted by Wu and Raja (2011) [4]. Reducing PONV is a critical aspect of improving patient satisfaction and comfort postoperatively, as it significantly affects the overall recovery experience.

Our findings support the notion that regional anesthesia techniques such as ESPB, which are associated with reduced opioid consumption, may also lead to a lower incidence of PONV. This underscores the multifaceted benefits of ESPB beyond pain relief, including improvements in overall postoperative outcomes.

Patient satisfaction

Although patient-reported outcomes were not extensively measured in this study, the reduced need for rescue analgesia and lower opioid consumption in the ESPB group suggest the potential for greater patient satisfaction. Patient satisfaction is a crucial aspect of postoperative care and significantly impacts the perceived success of surgical interventions. Gordon DB et al. reported that effective pain management strategies, such as ESPB, can increase patient satisfaction and overall quality of life [17]. Future studies should incorporate detailed patient satisfaction surveys to more comprehensively evaluate the subjective benefits of ESPB compared with WI.

Clinical and economic implications

The clinical advantages of ESPB, including prolonged analgesia and reduced opioid consumption, have significant implications for postoperative pain management. Furthermore, the economic impact of ESPB is also worth considering.  Cui Y et al. assessed the cost-effectiveness of ESPB, highlighting its potential financial benefits due to reduced opioid use and improved recovery outcomes [24]. The opioid-sparing effect of ESPB may lead to decreased healthcare costs associated with opioid-related side effects and faster patient recovery.

Here, it is important to address the cost factors associated with the use of ESPB, particularly the need for specialized equipment such as ultrasound machines, special needles, and the extra time required for administering the block under ultrasound guidance. These additional costs, in terms of both equipment and time, could be seen as a disadvantage, especially in resource-limited settings.

However, these upfront costs should be balanced against the long-term clinical and economic benefits demonstrated in this study. The significant reduction in opioid consumption and the prolonged analgesic effect observed in the ESPB group can translate into lower overall healthcare costs. Fewer opioids mean a reduced risk of opioid-related side effects, such as postoperative nausea and vomiting (PONV), respiratory depression, and constipation, which can require additional treatments and lengthen hospital stays.

Moreover, the superior pain control provided by ESPB, as reflected in the longer time to first rescue analgesia and reduced need for rescue medications, may also contribute to earlier mobilization, fewer postoperative complications, and possibly shorter hospital stays. This can improve patient outcomes and potentially reduce costs related to extended hospital care and interventions for opioid-related side effects.

Ultimately, while the initial setup for ESPB may be more costly and time-intensive, the superior clinical outcomes—such as reduced opioid use, prolonged analgesia, and enhanced patient recovery—justify the investment. These advantages align with the goals of modern multimodal analgesia protocols and enhanced recovery after surgery (ERAS) protocols, which focus on minimizing opioid consumption and improving overall patient recovery. Therefore, the cost of implementing ESPB should be viewed not only in terms of immediate expenses but also in the context of potential long-term savings and improved patient outcomes.

Further studies evaluating the cost-effectiveness of ESPB in larger and more diverse surgical settings would provide more comprehensive insights into its economic viability as part of routine postoperative pain management.

Study limitations

This study has several limitations that should be acknowledged. First, the study was conducted at a single institution, which may limit the generalizability of the findings. Multicenter studies involving diverse patient populations and varying clinical practices are needed to validate these results and ensure their applicability across different healthcare settings.

Additionally, the follow-up period was limited to 24 h postoperatively. While this time frame is adequate for assessing immediate postoperative pain and analgesic needs, it does not capture longer-term outcomes such as chronic pain development or functional recovery. Extended follow-up periods in future studies could provide valuable insights into the long-term effects of ESPB and WI on patient recovery and overall outcomes. Furthermore, patient-reported outcomes, such as satisfaction and quality of life, were not extensively evaluated in this study. Incorporating comprehensive patient-reported measures in future research could offer a more complete understanding of the relative benefits of ESPB versus WI from the patient’s perspective.

Another limitation of the study is the lack of a detailed cost-effectiveness analysis. Given the potential benefits of ESPB in reducing opioid consumption and improving recovery outcomes, an economic evaluation would be valuable in determining the feasibility of incorporating ESPB into standard pain management protocols. Additionally, the learning curve associated with ESPB was not assessed in this study. Understanding the training requirements and challenges in the widespread clinical adoption of ESPB is crucial for its effective implementation. Future studies should consider these aspects to ensure that ESPB can be efficiently and safely integrated into routine clinical practice.

Finally, the absence of a controlled group receiving standard analgesia without regional anesthesia is a further limitation of this study. This restricts our ability to evaluate the comparative efficacy of ESPB and wound infiltration against a baseline of conventional postoperative analgesia. Future studies should consider including a control group to provide a more comprehensive evaluation of these techniques in postoperative pain management.

Future directions

Future research should explore the long-term benefits of ESPB in various surgical populations, including its potential role in enhanced recovery protocols. Comparative studies involving other regional anesthesia techniques, such as transversus abdominis plane (TAP) block or paravertebral block (PVB), could provide valuable information on the relative efficacy of different regional anesthesia methods. Moreover, research into the combination of ESPB with other analgesic techniques may yield insights into optimizing pain management strategies for lumbar spinal surgeries and potentially other types of surgeries [25, 26].

Investigating the cost-effectiveness of ESPB compared with WI and other analgesic methods is also warranted. Understanding the economic implications will help determine the feasibility of adopting ESPB as a standard practice in postoperative pain management. Additionally, studies should examine the learning curve associated with ESPB to evaluate the necessary training and resources required for effective clinical implementation. This is particularly important for ensuring that ESPB can be safely and widely adopted in diverse clinical settings.

Finally, exploring the integration of ESPB into enhanced recovery after surgery (ERAS) protocols could provide insights into optimizing postoperative care and improving patient outcomes. Given its potential to offer effective pain relief with minimal side effects, ESPB may become an integral component of ERAS protocols, facilitating early mobilization and discharge, which are key goals in modern perioperative care.