Ultrasound-guided erector spinae plane block for perioperative analgesia in laparoscopic nephrectomy: A systematic review and meta-analysis

Abstract

BACKGROUND

Laparoscopic nephrectomy is a preferred surgical approach due to its minimally invasive nature and faster recovery times. However, effective management of postoperative pain remains a significant challenge. Several traditional methods, including opioid-based analgesia, are commonly used but are associated with side effects such as nausea, vomiting, sedation, and delayed recovery. In recent years, the erector spinae plane block (ESPB) has gained attention as an ultrasound-guided regional anesthesia technique offering promising results in various surgical procedures by reducing opioid requirements and enhancing patient comfort.

AIM

To evaluate the efficacy and safety of ESPB in comparison to conventional pain management strategies in patients undergoing laparoscopic nephrectomy.

METHODS

Following PRISMA guidelines, we searched PubMed, EMBASE, Web of Science, and the Cochrane Register for randomized controlled trials (RCTs) comparing ESPB with control for laparoscopic nephrectomy. The Cochrane Risk of Bias tool was employed for quality assessment. The primary outcome was total patient-controlled analgesia (PCA) consumption. Secondary outcomes included hospital discharge time and the incidence of postoperative nausea and vomiting. A random-effects meta-analysis was conducted to calculate pooled mean differences (MD) and odds ratios (OR) with 95%CIs.

RESULTS

Nine RCTs involving a total of 643 patients (ESPB group = 320; control group = 323) were included in the analysis. ESPB significantly reduced PCA opioid consumption compared to controls (MD: -14.24, 95%CI: -20.66 to -7.83, P < 0.0001). Subgroup analysis showed reduced PCA use with ESPB vs morphine (MD: -8.78, 95%CI: -15.34 to -2.22, P = 0.009), and a non-significant effect compared to other analgesics (MD: -48.26, 95%CI: -143.60 to 47.09). No statistically significant differences were observed in discharge time or the incidence of nausea and vomiting.

CONCLUSION

ESPB demonstrates the potential of reducing PCA in laparoscopic nephrectomy patients; however, its impact on secondary outcomes remains inconclusive. Large-scale RCTs are needed to confirm ESPB's benefits and explore long-term effects.

Key Words: Erector spinae plane block; Laparoscopic nephrectomy; Postoperative pain; Opioid sparing; Regional anesthesia; Nausea; Discharge time; Minimally invasive surgery; Meta-analysis

Core Tip: Erector spinae plane block (ESPB) demonstrates significant efficacy in reducing postoperative opioid use following laparoscopic nephrectomy, highlighting its potential as a promising alternative for enhanced pain management. While ESPB shows promise in lowering patient-controlled analgesia requirements compared to traditional methods, its impact on discharge times and nausea/vomiting remains inconclusive. Future large-scale randomized controlled trials are crucial to validate these findings and explore ESPB's long-term benefits in optimizing recovery pathways for nephrectomy patients.

INTRODUCTION

Laparoscopic nephrectomy is a minimally invasive procedure and has become a preferred technique for kidney removal[1]. It provides significant benefits over other conventional surgeries. One of the most beneficial outcomes is a marked reduction in blood loss, achieved by allowing smaller incisions during the procedures. This not only reduces the risk of significant bleeding but also offers shorter hospital stay, decreased pain at the surgical site, and quicker recovery[2]. Additionally, it provides better cosmetic outcomes due to minimal scarring from a smaller incision. However, despite the benefits of a smaller scar, shorter hospital stays, and a quick recovery, postoperative pain and its management remain a challenging and critical component in improving patient outcomes[3,4]. Effective pain management is crucial for patient care and recovery to avoid future complications of delayed recovery, chronic pain, and reduced mobility. Several traditional methods of pain relief include the consumption of nonsteroidal anti-inflammatory drugs and opioid analgesics, epidural analgesia, and a patient-controlled analgesia (PCA) system. However, these approaches are associated with a range of adverse effects like sedation, post-operative nausea and vomiting, respiratory depression, urinary retention, and most importantly, the development of chronic postsurgical pain (CPSP)[5]. CPSP is defined as the post-surgical pain that persists for at least two months. Patients with high severity of post-operative pain are more likely to have chronic pain[6]. To mitigate these complications and enhance patient outcomes, ultrasound-guided regional blocks have gained considerable popularity in recent years[7].

The fascial plane block is a regional technique that involves injecting a local anesthetic into space between fascial layers[7]. Fascia is a connective tissue structure that surrounds muscles, organs, blood vessels, and other structures throughout the body[8]. It is composed of superficial and deep fascia. Superficial fascia is a layer of loose connective tissue that lies beneath the skin and supports subcutaneous structures. In contrast, the deep fascia is a fibrous structure that encloses muscles, providing them with functional and structural support[9]. The fascial plane blocks target the deep fascia and the plane between them[10]. This approach has gained considerable popularity in recent years, and several new articles evaluating ultrasound-guided fascial blocks have been published.

The erector spinae plane block (ESPB) is one of the newest techniques in the field of interfascial plane blocks[11-18]. This procedure was first described by Forero et al[14] in 2016 as an alternative analgesic approach for various surgeries of the breast, abdomen, spine, and cardiac regions. EPSP involves the precise injection of local anesthetics, such as bupivacaine, ropivacaine, or lidocaine, into the space between the fascia of the erector spinae muscle and the tip of the thoracic or lumbar vertebrae[12,13]. This procedure is ultrasound guided to ensure accurate placement of the anesthetic allowing it to diffuse efficiently[16]. The analgesia is provided to the dorsal and ventral rami of the spinal nerves, thereby offering both somatic and visceral pain relief most commonly at T5-T7 paraspinal levels[7].

Various studies have been performed to determine the efficacy of ESPB in different surgical contexts, providing a solid groundwork for our meta-analysis mainly focused on laparoscopic nephrectomies. For instance, in 2016, research by Forero et al[14] was done that demonstrated the effectiveness of ESP block in managing thoracic and abdominal pain across various surgical procedure. Another meta-analysis, Viderman et al[15], reinforces the role of ESP block in pain management after major abdominal surgeries. However, despite these promising individual studies, there is a lack of proper consensus on effectiveness of ESPB in perioperative analgesia for laparoscopic nephrectomies, as various clinical trials have shown inconsistent results.

Although some previous reviews have looked at ESPB for different abdominal surgeries, very few have focused only on laparoscopic nephrectomy. This type of surgery has its own pain management challenges, and current research doesn’t clearly show how effective ESPB is in this specific context. Many studies compare ESPB only to no block or a placebo, while very few compare it to other commonly used techniques like quadratus lumborum or paravertebral blocks. Also, important recovery-related outcomes like side effects from opioids, hospital discharge time, and the need for extra pain medication are often missing or inconsistently reported. Because of these gaps, there is a need for a focused review that looks not only at how well ESPB controls pain, but also how it affects overall recovery in laparoscopic nephrectomy. By including different comparison groups and exploring factors like age and gender, this review aims to fill that gap and provide more useful information for clinical practice.

In conclusion, this meta-analysis aims to review the available evidence on the effectiveness and safety of ESPB. Data from multiple randomized controlled trials (RCTs) comparing ESPB to a control group were analyzed with comprehensive evaluation of ESPB on patients undergoing nephrectomies. This is not only to clarify analgesic efficacy but also to establish evidence-based guidelines to improve patient outcomes.

MATERIALS AND METHODS

Protocol registration

The objectives and methodologies of this meta-analysis were predefined in a protocol registered with PROSPERO[19]. The registration was accepted under the registration number CRD420251089216.

Data source and search strategy

The study was conducted following the PRISMA guidelines[19]. Comprehensive searches for randomized controlled trials (RCTs) were conducted using PubMed, EMBASE, Web of Science and Cochrane Central till July 2025. The research question was structured using the strategy design PICO (Population, Intervention, Control, Outcomes). Terms used in the search strategy included ‘erector spine plane block’, ‘ultrasound-guided erector spine plane block’, ‘laparoscopic nephrectomies’, and ‘nephrectomies’. No search filters were applied. The detailed search strategy is presented in Supplementary Table 1.

Study selection

The title and abstract of the articles were reviewed individually by three independent authors (Akram Z, Zainab B and Rizwan S). Full texts of the articles deemed relevant were then read thoroughly to confirm whether they met the eligibility criteria. This was done to ensure that only articles meeting specified criteria were selected for the final analysis. Any discrepancy was resolved by a third author (Siddiqui AH). The studies were considered eligible for inclusion if: (1) Patients received ESPB as intervention treatment; (2) They were undergoing radical, partial or laparoscopic nephrectomies under general anesthesia; (3) Patients with American Society of Anesthesiologists (ASA) physical status I-III; (4) Randomized control trials; and (5) Articles in the English language. The research screening excluded non-English literature. Single arm studies and studies not having relevant outcomes or original data were excluded. Letters, case reports, case series, reviews, editorials were also excluded.

Study outcomes

The primary outcome of interest was PCA (morphine milligram equivalent). The secondary outcomes of interest included post-operative additional analgesic requirement, discharge time (in days), and incidence of nausea and vomiting (Supplementary Tables 2 and 3).

Data extraction

Data extraction was conducted by two independent reviewers and any discrepancies were resolved through discussion with Siddiqui AH. The extracted data was recorded on an excel sheet and included: Study characteristics (type of study, author, year of publication), population characteristics [the number of patients, age, gender, body mass index (BMI), any known comorbidities], ASA classification, primary and secondary outcomes and pre-operative evaluation.

Study quality assessment

Two authors Mukhtar S and Amir S independently assessed the quality of the clinical trials by using the Revised Cochrane risk-of-bias tool for randomized trials (ROB 2)[20]. The factors evaluated were measurement of the outcome, randomization process, selective reporting, missing data, and overall bias. Based on these factors, each trial was categorized as having either high risk, low risk, or some concerns.

Statistical analysis

The meta-analysis was performed using Review Manager (version 5.4.1). A random effects meta-analysis was conducted. For dichotomous variables, the odd ratio (OR) and 95%CI were calculated while continuous outcomes were analyzed by calculating the mean difference (MD) with their 95%CI. Statistical significance was set at P < 0.05. Heterogeneity was assessed by calculating I² values. The values between 50%-75%, were considered as moderate heterogeneity while values > 75% were indicative of severe heterogeneity. Sensitivity analysis was performed for studies exhibiting high heterogeneity to identify the impact of potential sources of variations. Comprehensive meta-analysis (V4) was used for meta-regression and a random effects model was used. Results of meta-regression were reported as coefficients (Coeff) and P-values.

RESULTS

Study selection and characteristics

Initially, a pool of 4049 studies was collected from searched databases. After title and abstract review, 121 articles underwent full-text screening. Following the exclusion criteria, articles were rejected due to lack of control group, irrelevant patient population, and studies without original data such as reviews and editorials. 9 RCTs were included in the meta-analysis after reviewing the studies and eliminating the duplicates. In these studies, 643 patients (ESPB = 320, control = 323) undergoing laparoscopic nephrectomy were included. The summary of this process is included in the PRISMA chart as shown in Figure 1. Table 1 summarizes the baseline patient characteristics of the included studies. 3 studies compared ESPB with no block[22-24], for the other Six studies, the type of control was 0.9% saline[25], quadratus lumborum block[26,27], paravertebral block[28], transversus abdominis plane block[29] and general anesthesia along with local wound infiltration[30]. The patients included were late middle-aged, ranging between 50 and 70 years, with an average BMI of 20-30 kg/m². Notably, none of the patients in the studies had any reported comorbidities.

Figure 1 The PRISMA flow diagram 2020. RCT: Randomized controlled trial.

Table 1 Baseline characteristics of included randomized controlled trial, mean ± SD.

Ref.	Total number of patients	Number of patients in each group		Age		Gender (male/female)		BMI		Physical status (ASA I/II/III)		Type of PCA
		ESPB	Control	ESPB	Control	ESPB	Control	ESPB	Control	ESPB	Control
Şahin et al[23], 2022	60	30	30	57.0 ± 6.5	53.8 ± 8.9	17/13	16/14	30.6 ± 4.9	27.6 ± 3.3	N/A	N/A	Tramadol
Xu et al[28], 2023	166	83	83	66 ± 5.93	63 ± 8.89	45/38	38/45	25 ± 3.70	24 ± 2.96	9/58/16	7/62/14	Sulfentanil
Özkalayci et al[24], 2023	52	25	27	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	Morphine
Onay et al[26], 2023	40	20	20	60.95 ± 8.38	55.15 ± 10.08	14/16	12/8	27.95 ± 4.08	28.4 ± 4.52	0/16/4	1/15/4	Morphine
Yang et al[25], 2024	50	23	23	52.08 ± 7.65	50.3 ± 8.59	14/9	11/12	24.5 ± 3.13	22.95 ± 2.78	2/20/1	1/21/1	N/A
Atıcı et al[22], 2024	46	20	20	52.5 ± 9.36	51.45 ± 9.36	13/7	14/6	28.35 ± 1.63	27.95 ± 3.30	6/14/0	5/15/0	Morphine
Zhang et al[27], 2024	110	55	55	53 ± 11	53 ± 9	35/20	28/27	24.8 ± 3.3	24.6 ± 3.1	20/29/6	18/28/9	Sufentanil
Özfırat et al[29], 2025	50	25	25	54.4 ± 12.1	52.4 ± 15.9	13/12	12/11	27.7± 3.7	26.4 ± 4.9	10/15/0	12/13/0	Morphine
Loganathan et al[30], 2025	69	34	35	48 ± 10	45 ± 10	8/26	4/31	N/A	N/A	10/15/0	12/13/0	Morphine

BMI: Body mass index; ASA: American Society of Anesthesiologists; PCA: Patient-controlled Analgesia; ESPB: Erector spinae plane block; N/A: Not applicable.

Primary outcome

PCA: Out of nine studies, PCA was evaluated in six studies as an outcome. The result shows that in PCA a statistically significant reduction is seen in the ESPB group as compared to the control group (MD: -14.24, 95%CI: -20.66 to -7.83, I²: 99%, P < 0.0001) (Figure 2A).

Figure 2 Forest plot. A: Patient-controlled analgesia; B: Discharge time; C: Adverse effects nausea and vomiting; D: Post-operative analgesia requirement. ESPB: Erector spinae plane block.

For subgroup analysis it was divided into two categories according to the type of analgesia: ESPB vs morphine and ESPB vs analgesia other than morphine. In the morphine subgroup, 4 studies were analyzed with 201 patients (99 patients in ESPB group and 102 patients in control group). The forest plot generated for this suggested that the result is statistically significant (MD: -8.78, 95%CI: -15.34 to -2.22, I² = 89%., P = 0.009). In the subgroup having analgesia other than morphine, 2 studies and 226 patients were included in the analysis. The results showed no significant overall (MD: -48.26, 95%CI: -143.60 to 47.09, I² = 99%, P = 0.32). There was no significant difference between the subgroups with a P value of 0.42 and heterogeneity was also low as shown in Figure 2A. However, potential sources of clinical heterogeneity such as differences in surgical techniques, ESPB injection site or level, anesthetic concentration, and perioperative protocols were not explored, which may partly explain the high I² values.

Secondary outcome

Discharge time: Four studies assessed the discharge time taken for the patients as an outcome. There was no statistically significant reduction in discharge time (MD: -0.11, 95%CI: 0.27-0.06, I² = 0%, P = 0.20). Heterogeneity was low, which indicates similarity in the results of the studies as shown in Figure 2B.

Nausea and vomiting

The incidence of nausea and vomiting was reported in four studies. The findings showed that there is no significant impact in the adverse effects when compared to control (MD: -0.09, 95%CI: -0.36 to 0.17, I² = 76%, P = 0.50) as shown in Figure 2C.

Post-operative analgesia requirement

Post-operative analgesia requirements were reported in five studies. There was no significant reduction in the requirement of post-operative analgesia in ESPB group as compared to control treatments (OR = 0.84, 95%CI: 0.10-6.94, I² = 86%, P = 0.87). Heterogeneity was severe as shown in Figure 2D.

Sensitivity analysis

A sensitivity analysis was performed for all the outcomes after identifying and excluding RCTS with low-quality assessment scores or studies with different demographics, or the number of patients in both groups. For our primary outcome, PCA the heterogeneity did not reduced after leaving out any studies and remained I² = 99%. For secondary endpoints like nausea and vomiting the heterogeneity reduced after removing[21] (I² = 76%- I² = 0%) (Figure 3A) and for post-operative analgesia requirement (I² = 86%-I² = 59%) after removing[46-48] as given in the Figure 3B.

Figure 3 Sensitivity analysis forest plot. A: Nausea and vomiting; B: Post-operative analgesia requirement. ESPB: Erector spinae plane block.

Meta-regression analysis

The analysis of our primary outcome showed that age had a statistically significant effect on PCA (Coeff = 0.1855, P = 0.0047) (Supplementary Figure 1), while gender did not (Coeff = - 0.0233, P = 0.5729) (Supplementary Figure 2). In the secondary outcomes age had no association to the incidence of nausea and vomiting (Coeff = 0.0200, P = 0.7419) (Supplementary Figure 3), while gender showed a statistically significant association (Coeff = -0.0658, P = 0.0267) (Supplementary Figure 4). For outcome Discharge time age did not have a significant effect (Coeff = 0.0130, P = 0.4857) (Supplementary Figure 5) and gender also did not have significant association (Coeff = -0.0157, P = 0.1439) (Supplementary Figure 6). Similarly for post operative analgesia requirement, age did not have significant effect (Coeff = -0.0157,P = 0.9264) (Supplementary Figure 7) while gender showed statistically significant association (Coeff = -0.1827, P = 0.0299) (Supplementary Figure 8).

Quality assessment and publication bias

The quality of the clinical trials was assessed by the ROB 2 and the risk of bias within these trials is shown in the form of a traffic light plot and the summary plot in Figure 4 and Supplementary Figure 9. The overall bias has some concerns, as one study had missing outcome data and was rated as high risk, while the remaining studies were mostly at low risk or had minor concerns. As illustrated in the domain-specific plots, the most frequent issue was bias due to missing outcome data (Domain 3), followed by some concerns in the selection of the reported result (Domain 5) (Table 2). A funnel plot was also generated to assess publication bias for our primary outcome as shown in the Supplementary Figure 10. As the studies are concentrated and asymmetrical it shows publication bias.

Figure 4 Traffic light plot showing the risk of bias assessment per domain for each included randomized controlled trials using risk-of-bias tool. Green: Low risk; Yellow: Some concerns; Red: High risk.

Table 2 Results using the risk of bias tool 2.

Ref.	D1	D2	D3	D4	D5	Overall
Şahin et al[23], 2022	+	+	-	+	+	-
Xu et al[28], 2023	+	+	!	+	+	+
Özkalayci et al[24], 2023	+	+	+	+	!	+
Onay et al[26], 2023	+	+	!	+	+	+
Yang et al[25], 2024	+	+	+	+	!	+
Atıcı et al[22], 2024	+	+	+	!	+	+
Zhang et al[27], 2024	+	+	+	+	+	+
Özfırat et al[29], 2025	+	+	+	+	+	+
Loganathan et al[30], 2025	+	+	+	+	+	+

+: Low risk; !: Some concerns; -: High risk. D1: Randomization process; D2: Deviation from the intended interventions; D3: Missing outcome data; D4: Measurement of the outcome; D5: Selection of the reported result.

GRADE approach: Employing the GRADE approach, the overall certainty of evidence was rated as high for all outcomes. The primary outcome, PCA reduction, showed a significant MD of -14.24 mg (95%CI: -20.66 to -7.83) favoring ESPB. Subgroup analyses for PCA vs morphine (MD: -8.78, 95%CI: -15.34 to -2.22) and PCA vs other analgesics (MD: -48.26, 95%CI: -143.60 to 47.09) were also rated as high certainty. Secondary outcomes, including discharge time (MD: -0.11 days, 95%CI: -0.27 to 0.06), nausea and vomiting (MD: -0.09, 95%CI: -0.36 to 0.17), and postoperative analgesia requirement (OR = 0.84, 95%CI: 0.10-6.94), were similarly rated with high certainty, based on consistency of study designs, precise estimates, and according to the risk of bias across included randomized trials. This is given in the Supplementary Table 4.

DISCUSSION

This meta-analysis evaluated the efficacy and safety of the ESPB compared to traditional pain management methods in patients undergoing laparoscopic nephrectomy.

Our meta-analysis findings demonstrated that ESPB significantly reduced PCA use compared to control interventions (MD: -14.24, 95%CI: -20.66 to -7.83, I2: 99%, P < 0.0001). These findings of reduced PCA use with the ESPB during laparoscopic nephrectomy align with results from various studies evaluating ESPB's efficacy across different surgical contexts[13]. For example, Tulgar et al[31] reported that ESPB significantly lowered opioid consumption in patients undergoing abdominal surgeries, a pattern similar to the reduced PCA use observed in our analysis[32]. Similarly, Gürkan et al[33] demonstrated the block's effectiveness in thoracic surgery, where patients receiving ESPB experienced lower pain scores and decreased opioid requirements compared to control groups. In spinal surgeries, Krishna et al[34] found that ESPB reduced both opioid consumption and postoperative pain scores, further confirming its role in minimizing analgesic use.

The magnitude of the observed reduction in PCA use (MD: -14.24 mg) appears clinically relevant when contextualized with earlier studies, where reductions ranged from 10–25 mg morphine equivalents in similar abdominal procedures. This degree of opioid sparing could translate into a reduced incidence of opioid-related side effects such as respiratory depression, nausea, and sedation, especially in high-risk populations.

The effectiveness of ESPB can be attributed to its underlying physiological mechanism. By depositing local anesthetic near the transverse processes of the vertebrae, ESPB targets the dorsal rami of spinal nerves, which innervate the posterior thoracic and abdominal walls[11]. This blockade leads to both somatic and visceral analgesia, providing broad coverage of the affected region and reducing the need for systemic analgesics like opioids. Consequently, the widespread effect on pain pathways explains the significant reduction in PCA use in our study, highlighting ESPB’s potential for improved postoperative pain control[35].

Recent anatomical and clinical studies have highlighted the complexity and variability in the spread of local anesthetics with ESPB, which could explain its differing clinical effectiveness. Forero et al[14] initially described how injectate can extend cranially and caudally within the fascial plane to affect both dorsal and ventral rami of spinal nerves[14]. More contemporary imaging by Shan et al[36] found that a significant majority of ESPB injections reached the paravertebral space and neural foramina, though the extent depended on patient positioning[42]. Sartawi et al[37] confirmed this variable spread using soft-embalmed cadavers, noting differences when comparing ESPB to the retro-laminar block. In terms of clinical comparisons, Durey et al[38] found that ESPB was less effective than paravertebral block in thoracic surgery, reinforcing the need for comparative evaluation of ESPB with other regional techniques. This underlines how both anatomical factors and choice of comparator block may influence outcomes, a source of variability that warrants further exploration in future studies.

The subgroup analysis by analgesic type in our meta-analysis revealed a significant trend toward reduced PCA use with ESPB compared to morphine (MD: -8.78, 95%CI: -15.34 to -2.22, P = 0.009). Still, no significant effect was found when compared to other analgesics (MD: -48.26, 95%CI: -143.60 to 47.09, P = 0.32). This is consistent with Forero et al[14] who first described ESPB and noted its broad applicability in reducing postoperative pain and opioid consumption across various surgeries. Morphine’s unique pharmacodynamics might help explain these results. As a potent opioid that acts on mu-opioid receptors, morphine often provides more substantial pain relief compared to other analgesics, which could make it harder to show a significant difference with ESPB[39]. Additionally, morphine’s slower onset and prolonged duration of action might obscure the immediate postoperative pain-relief benefits of ESPB, especially when compared to analgesics with shorter half-lives or different mechanisms of action[40,41]. The lack of statistical significance in some subgroups may also be due to small sample sizes and varying analgesic protocols in the included studies, which could have introduced inconsistencies in how the ESPB's regional effect interacts with different drugs. Importantly, the observed discrepancy between the overall significant PCA reduction and the significant result in the morphine subgroup and no-significant result in the subgroup of analgesics other than morphine may reflect limitations in statistical power or subgroup-specific heterogeneity and should be interpreted with caution.

The secondary outcomes in your meta-analysis, including discharge time and the incidence of nausea and vomiting, did not show significant differences between the ESPB and control groups (MD: -0.11 days, 95%CI: -0.27 to 0.06, P = 0.20) and (MD: -0.09, 95%CI: -0.36 to 0.17, P = 0.50) respectively. These findings align with Liheng et al[42] who also reported no significant differences in discharge times between patients receiving regional blocks and those receiving traditional analgesia, suggesting that while ESPB is effective in reducing opioid consumption, its impact on other postoperative outcomes remains uncertain[43,44]. The lack of significant reduction in the incidence of nausea and vomiting may be due to various factors beyond pain management, including the type of surgery performed, anesthesia used, and individual patient characteristics, as specific surgical procedures may inherently carry a higher risk of postoperative nausea and vomiting[45]. Additionally, while ESPB can effectively manage pain and reduce opioid use, it may not address other mechanisms contributing to nausea, such as vestibular disturbances or the side effects of anesthesia[46]. Traditional analgesics like opioids, despite their adverse effects, may have a more direct impact on nausea-related pathways, potentially explaining why a reduction in opioid consumption does not translate to lower rates of nausea and vomiting[47]. Furthermore, variability in discharge protocols and criteria across different studies may affect reported discharge times[48] as each institution may have its own discharge criteria based on various clinical factors, which can obscure the effects of ESPB on this outcome. Notably, the odds ratio for postoperative analgesic demand (OR = 0.84, 95%CI: 0.10-6.94, P = 0.87) was not statistically significant, though the wide confidence interval suggests uncertainty and highlights the need for further research.

While earlier reviews have looked at ESPB in general abdominal or urologic surgeries, this is the first one to focus only on laparoscopic nephrectomy. That’s important because this surgery has specific pain and recovery patterns that may not apply to other procedures. Our study also stands out because it compares ESPB not just to placebo or no block, but to other widely used blocks like quadratus lumborum and paravertebral block. Such variability in comparator techniques could also contribute to heterogeneity in treatment effects, a factor that future subgroup analyses may explore in more depth. We also examined recovery outcomes, including nausea, vomiting, discharge time, and the need for extra pain medicine, which aren’t often included in earlier reviews. In addition, we performed subgroup analyses and meta-regression to examine the potential impact of age and gender on the results. These extra steps helped us understand how ESPB works in different situations. Meta-regression revealed a significant association between age and PCA consumption (Coeff = 0.1855, P = 0.0047), suggesting that older patients may derive greater benefit from ESPB, and age may influence the analgesic effectiveness of ESPB, potentially due to altered pain perception or opioid sensitivity in older adults. Additionally, gender was significantly associated with both nausea and vomiting (P = 0.0267) and postoperative analgesic requirement (P = 0.0299), indicating that demographic variables may influence ESPB outcomes. However, these findings require cautious interpretation due to the small number of studies. Overall, this review doesn’t just repeat what’s already known, it offers new insights that can help guide better pain management decisions for patients having laparoscopic nephrectomy. Furthermore, our exclusive inclusion of RCTs ensures a high level of evidence, reinforcing the reliability of our findings.

The limitations of this meta-analysis include high heterogeneity among the included studies, a relatively small sample size, and potential publication bias. The high heterogeneity could be due to variations in patient demographics, surgical techniques, and pain management protocols. The exclusion of non-English studies may have also introduced language bias, but it is unlikely to influence the anlaysis and change conclusions. Additionally, potential sources such as ESPB injection level, drug dosage, surgical approach, and comparator block type were not systematically explored and may account for outcome variability. However, the limited number of included studies and the relatively small sample sizes are notable limitations. Publication bias, indicated by asymmetrical funnel plots, suggests an overrepresentation of studies with positive outcomes, which is a common issue in meta-analysis.

Future research should focus on conducting larger-scale RCTs with standardized methodologies to elucidate further the efficacy and safety of ESPB in laparoscopic nephrectomy patients. Additionally, exploring long-term outcomes such as chronic pain development and patient satisfaction could provide more comprehensive insights into the clinical benefits of ESPB. Studies comparing ESPB with other advanced regional anesthesia techniques, such as quadratus lumborum block or transversus abdominis plane block, could also be valuable in determining the most effective pain management strategies for laparoscopic nephrectomy patients.

CONCLUSION

In conclusion, this meta-analysis reveals that ESPB significantly reduces PCA usage in laparoscopic nephrectomy patients, demonstrating its potential for effective postoperative pain management. This reduction in PCA use may translate into decreased opioid-related adverse events, such as nausea, sedation, or respiratory depression, thereby underscoring the clinical relevance of ESPB. However, secondary outcomes, such as discharge time and the incidence of nausea and vomiting, showed no significant differences between the ESPB and control groups. The high heterogeneity observed across studies highlights the need for standardized methodologies in future research. Moreover, the relatively small sample size and potential publication bias limit the generalizability of these findings. Based on current evidence, ESPB may be considered as an effective adjunctive analgesic technique rather than a standalone replacement for traditional analgesia. Future studies should aim to include larger, well-designed RCT to investigate the efficacy and safety of ESPB further. Additionally, exploring long-term outcomes like chronic pain development and patient satisfaction, as well as comparing ESPB with other regional anesthesia techniques, could provide more comprehensive insights into optimizing pain management strategies for laparoscopic nephrectomy patients.