Comparison of erector spinae plane block and paravertebral block on quality of recovery-15 after video-assisted thoracoscopic surgery: a prospective randomized study

Abstract

Background

Postoperative pain remains a significant concern after video-assisted thoracoscopic surgery (VATS), potentially impairing recovery quality. Thoracic erector spinae plane block (ESPB) and paravertebral block (PVB) are widely used regional anesthesia techniques integrated into multimodal analgesia protocols. This study compared their effects on postoperative recovery quality and pain control.

Methods

In this prospective randomized study, 60 adult patients undergoing elective VATS were allocated to receive either ESPB (n = 30) or PVB (n = 30) at the T4–T5 level under ultrasound guidance. The primary outcome was postoperative quality of recovery assessed by the validated Turkish version of the Quality of Recovery-15 (QoR-15) questionnaire. Pain intensity was measured using the Numeric Rating Scale (NRS). Additional outcomes included opioid consumption, length of hospital stay (LOS), rescue analgesia requirement, and complications.

Results

Preoperative QoR-15 scores were comparable between groups. At 24 h postoperatively, QoR-15 scores were significantly higher in Group PVB than in Group ESPB (139.40 ± 7.38 vs. 134.90 ± 8.70; p = 0.024; Cohen’s d = 0.56), although the between-group difference did not reach the minimal clinically important difference. The decline in QoR-15 from baseline was greater in Group ESPB (− 11.50 [− 15.00 to − 8.00] vs. −7.50 [− 10.00 to − 4.00]; p = 0.001; r = 0.41). Longitudinal analysis of postoperative NRS scores demonstrated a significant group × time interaction (p = 0.001). Pain scores at postoperative 0 h were significantly lower in Group PVB (p = 0.002), whereas no significant between-group differences were observed at later time points (2–24 h). Opioid consumption, LOS, rescue analgesia requirements, and complication rates were comparable between groups (p > 0.05).

Conclusion

PVB was associated with lower early postoperative pain scores and higher QoR-15 scores at 24 h compared with ESPB; however, the between-group difference in QoR-15 was below the minimal clinically important difference. Overall opioid consumption and clinical outcomes were comparable. Further multicenter studies are needed to determine whether these findings translate into clinically meaningful long-term benefits.

Trial Registration

ClinicalTrials.gov (ID NCT06558331). The clinical trial was prospectively registered on August 14, 2024.

Introduction

Video-assisted thoracoscopic surgery (VATS) has gained widespread acceptance as a minimally invasive surgical technique that offers several advantages over conventional thoracotomy, including reduced tissue trauma, shorter hospital stays, and faster postoperative recovery [1]. Despite these benefits, postoperative pain following VATS remains a significant concern, with many patients experiencing moderate to severe discomfort in the recovery period [2]. Effective perioperative pain management remains a critical component in optimizing surgical outcomes and enhancing the patient experience [3].

In recent years, regional anesthesia techniques such as the thoracic erector spinae plane block (ESPB) and the paravertebral block (PVB) have been integrated into multimodal analgesia protocols to address this issue [4]. Both blocks, administered under ultrasound guidance at the thoracic vertebral levels T4–T5, aim to provide targeted analgesia with minimal systemic side effects [5]. These techniques may contribute not only to improved pain control but also to overall postoperative recovery by reducing opioid consumption, facilitating early mobilization, and enhancing patient satisfaction [6].

The Quality of Recovery-15 (QoR-15) is a validated multidimensional instrument that assesses postoperative recovery across several domains, including physical comfort, emotional state, physical independence, and psychological support [7]. The validated Turkish version of the QoR-15 questionnaire has been shown to be a reliable and sensitive tool for evaluating perioperative recovery [8]. Assessing QoR-15 both preoperatively and postoperatively allows for a structured evaluation of the impact of analgesic interventions on recovery [9].

This study aimed to compare the effects of ESPB and PVB on postoperative recovery quality, as assessed by QoR-15, and postoperative pain using the Numeric Rating Scale (NRS) in patients undergoing VATS.

Materials and methods

Study design and ethics approval

This study was designed as a prospective randomized clinical trial conducted at Basaksehir Cam and Sakura City Hospital to evaluate and compare the effects of ESPB (Group ESPB) and PVB (Group PVB) in patients undergoing VATS. The trial was registered at ClinicalTrials.gov (Identifier: NCT06558331) and approved by the local Ethics Committee on April 03, 2024 (Protocol number: KAEK/03.04.2024.245). Informed consent was obtained from all patients. This manuscript adheres to the applicable CONSORT guidelines. Our study recognizes the Declaration of Helsinki as a statement of ethical principles for medical research involving human participants.

Patient population and randomization

Eligible participants were adult patients aged 18 years or older with an American Society of Anesthesiologists (ASA) physical status classification of I to III who were scheduled for elective VATS between September 1, 2024, and February 5, 2025.

Exclusion criteria included patients undergoing sympathectomy, lobectomy, or pneumonectomy via VATS; those whose procedures were converted from VATS to thoracotomy; patients who were uncooperative or declined to participate; individuals with neuropsychiatric conditions that could interfere with QoR-15 assessment; patients undergoing emergency surgery; and those younger than 18 years of age. In addition, patients with contraindications to regional anesthesia (e.g., coagulopathy, local infection at the injection site, or allergy to local anesthetics) were excluded. Patients with known chronic pain or those receiving opioids or other analgesics for chronic pain management were also excluded.

Patients were assigned to either the Group ESPB or Group PVB using a computer-generated randomization list to ensure unbiased allocation. Allocation concealment was maintained using sealed, opaque envelopes, which were opened immediately before block performance by the anesthesiologist performing the procedure. Due to the nature of the intervention, the anesthesiologist performing the block was not blinded. However, all blocks were performed under standardized conditions, and patients were not informed about group allocation. All regional blocks were performed by the same anesthesiologist, while perioperative follow-up and postoperative outcome assessments, including QoR-15 scoring and pain evaluations, were conducted by a separate anesthesiologist who was blinded to group allocation.

The groups were compared in terms of demographic characteristics (age, sex, ASA physical status, height, weight, and body mass index [BMI]), anesthesia and operative durations, length of hospital stay (LOS), quality of recovery assessed using the QoR-15 questionnaire, pain scores evaluated using the NRS, rescue analgesia requirements, opioid consumption, and perioperative complications (e.g., postoperative nausea and vomiting [PONV] and arrhythmia).

Study groups and interventions

Patients were randomly allocated into two groups according to the regional anesthesia technique applied: Group ESPB and Group PVB. In both groups, the procedures were performed under sterile conditions with the patient in a seated position. A 22G, 80-mm insulated needle was inserted in-plane under ultrasound guidance (Fujifilm Arietta 65, Tokyo, Japan) at the T4–T5 vertebral level on the surgical side, selected due to its proximity to the thoracic surgical field and the corresponding dermatomes.

In Group ESPB, the needle was advanced to the fascial plane between the erector spinae muscle and the transverse process. After negative aspiration, 1 mL of saline was injected to perform hydrodissection, facilitating separation of the fascial layers and confirming correct needle placement before administering the local anesthetic. A total of 30 mL of 0.25% bupivacaine was injected.

In Group PVB, the needle was directed toward the paravertebral space adjacent to the T5 vertebral body. Correct placement was confirmed by observing pleural depression (indentation) following minimal saline injection, which is a key sonographic sign indicating appropriate positioning above the pleura. After negative aspiration, 20 mL of 0.375% bupivacaine was administered.

Perioperative management

In the preoperative period, standard ASA monitoring was initiated, including electrocardiography, pulse oximetry, and non-invasive blood pressure measurement. Patients received 2 mg intravenous midazolam as premedication before block performance. General anesthesia was induced with fentanyl 2 mcg/kg, propofol 1.5–3 mg/kg, and rocuronium 0.6 mg/kg. Anesthesia was maintained with 1 minimum alveolar concentration (MAC) sevoflurane and remifentanil at a dose of 0.05–0.2 mcg/kg/min in a 50% oxygen–air mixture. All patients underwent orotracheal intubation with an appropriately sized double-lumen endotracheal tube, and correct placement was confirmed by fiberoptic bronchoscopy before positioning the patient.

For intraoperative hemodynamic monitoring, an invasive arterial catheter was placed in the upper extremity on the non-operative side to allow continuous blood pressure monitoring throughout the procedure. Surgical procedures were performed using the VATS technique. All patients were positioned in the lateral decubitus position, and three ports were placed on the operative side. A 10-mm thoracoscope was introduced through a camera port typically positioned at the sixth intercostal space along the midaxillary line. The main working port was inserted at the fifth intercostal space along the anterior axillary line, and the auxiliary port was placed at the seventh or eighth intercostal space along the posterior axillary line. Port placement was planned according to the target pulmonary lobe and surgeon preference to optimize access. Thoracoscopic resection was performed under video guidance. At the end of the procedure, a 28-Fr chest tube was inserted through the inferior port site to ensure postoperative drainage and lung re-expansion. All surgical procedures were carried out by the same experienced thoracic surgery team according to standardized protocols.

At the end of surgery, patients received 4 mg intravenous ondansetron, 1 g paracetamol, and 100 mg tramadol. Neuromuscular blockade was reversed with sugammadex at a dose of 2–4 mg/kg. Patients with a NRS score ≤ 4 were transferred to the ward. Postoperatively, patients routinely received paracetamol 1 g four times daily and tramadol 100 mg four times daily. Rescue analgesia consisted of intravenous morphine 0.1 mg/kg when the NRS score exceeded 4.

Intervention and assessment structure

To comprehensively evaluate postoperative recovery, all patients completed the validated Turkish version of the QoR-15 [8] questionnaire during the preoperative period (baseline) and again at the 24th postoperative hour. The QoR-15 evaluates five dimensions of recovery, including physical comfort, emotional state, psychological support, physical independence, and pain, providing a global score that reflects overall recovery quality from the patient’s perspective.

Postoperative pain intensity at rest was assessed using the NRS. Pain was recorded at predefined postoperative time points (0, 2, 6, 12, and 24 h) using a scale ranging from 0 (no pain) to 10 (worst imaginable pain), allowing standardized comparison of analgesic efficacy between groups.

Outcome measurements

The primary outcome of the study was QoR-15. Pain scores assessed using the NRS were defined as a secondary outcome. Additional outcomes included opioid consumption, LOS, rescue analgesia requirement, and complications. Based on the previously observed QoR-15 score difference between the PVB and control groups (140.3 ± 5.2 vs. 132.0 ± 12.0) and the calculated large effect size (Cohen’s d = 0.90), a minimum of 28 patients per group was required to detect a statistically significant difference with a 5% significance level and 90% power [10]. To account for potential dropouts, the planned sample size was at least 30 patients per group.

Statistical analysis

All statistical analyses were performed using SPSS version 27.0 for Mac OS (IBM Corp., Armonk, NY, USA). The normality of continuous variables was assessed using the Shapiro–Wilk test. Normally distributed data were presented as mean ± standard deviation (SD), whereas non-normally distributed data were expressed as median (interquartile range, IQR). Student’s t-test was used for comparisons of normally distributed continuous variables, while the Mann–Whitney U test was applied for non-normally distributed variables. Categorical variables were analyzed using the Chi-square test or Fisher’s exact test, as appropriate.

Repeated postoperative NRS measurements obtained at 0, 2, 6, 12, and 24 h were analyzed using a linear mixed-effects model including fixed effects for group, time, and group × time interaction, with patient included as a random effect to account for within-subject correlations. Pairwise comparisons between groups at each time point were performed using estimated marginal means with Bonferroni adjustment for multiple comparisons. Degrees of freedom were estimated using the Kenward–Roger method.

The change in QoR-15 from baseline (ΔQoR-15) was calculated as the postoperative minus the preoperative score and compared between groups. Effect sizes were calculated using Cohen’s d for parametric variables and effect size r (Z/√N) for Mann–Whitney U analyses. All tests were two-tailed, and a p-value < 0.05 was considered statistically significant.

Results

A total of 68 patients were initially assessed for eligibility. Eight patients were excluded prior to randomization due to refusal to participate, preoperative changes in the surgical procedure, or other reasons. Consequently, 60 patients were randomized and equally allocated into two groups: ESPB (n = 30) and PVB (n = 30) (Fig. 1).

Fig. 1.

Consort Flow Diagram

No statistically significant differences were observed between the groups in terms of age, sex, ASA physical status, height, weight, and BMI, as well as anesthesia and operative durations. Similarly, LOS, rescue analgesia requirement, opioid consumption, and complication rates were comparable between the groups (p > 0.05) (Table 1).

Table 1.

Demographic characteristics of the patients

	Group ESPB(n = 30)	Group PVB(n = 30)	p-value
Age (years)	37.00 [21.50–55.25]	40.00 [25.00–56.00]	0.544†
Sex (Male/Female)	16 / 14	19 / 11	0.432‡
ASA Score (1/2/3)	6 / 16 / 8	5 / 18 / 7	0.871‡
Height (cm)	166.53 ± 10.86	170.37 ± 10.77	0.174*
Weight (kg)	68.63 ± 11.86	66.37 ± 10.77	0.442*
BMI (kg/m²)	25.44 [20.80–29.41]	22.34 [19.74–24.93]	0.115†
Anesthesia Time (minute)	92.50 [85.00–113.75]	90.00 [79.25–108.75]	0.481†
Operation Time (minute)	65.00 [55.00–78.75]	60.00 [46.25–70.00]	0.319†
LOS (day)	2.50 [2.00–4.00]	3.00 [2.00–4.75]	0.268†
Rescue Analgesia (n/n)	9	7	0.770‡
Opioid consumption (MME)	40.00 [40.00–43.00]	40.00 [40.00–40.00]	0.518†
Complications (n/n) (PONV/arrhythmia)	1/0	2/1	0.495‡

BMI Body Mass Index, ASA American Society of Anesthesiologists, LOS length of stay, MME Morphine Milligram Equivalent, PONV Postoperative Nausea and Vomiting

^* Mean ± SD; independent samples t-test, ^† Median (IQR); Mann–Whitney U test, ^‡ n; Chi-square test, p-value < 0.05 statistically significant

Preoperative QoR-15 scores were comparable between the groups (150.00 [148.00–150.00] in Group ESPB vs. 150.00 [143.50–150.00] in Group PVB, p = 0.370). At 24 h postoperatively, QoR-15 scores were significantly lower in Group ESPB than in Group PVB (134.90 ± 8.70 vs. 139.40 ± 7.38; p = 0.024), corresponding to a moderate effect size (Cohen’s d = 0.56). The change in QoR-15 from baseline to 24 h (ΔQoR-15) also differed significantly between the groups (p = 0.001). Group ESPB demonstrated a greater decline in QoR-15 than Group PVB (− 11.50 [− 15.00 to − 8.00] vs. −7.50 [− 10.00 to − 4.00], respectively), with a moderate-to-large effect size (r = 0.41) (Table 2).

Table 2.

Quality of Recovery-15 (QoR-15) scores of the patients

	Group ESPB(n = 30)	Group PVB(n = 30)	p-value
Preoperative QoR-15	150.00 [148.00–150.00]	150.00 [143.50–150.00]	0.370†
Postoperative QoR-15	134.90 ± 8.68	139.40 ± 7.38	0.024 *
Cohen’s d (QoR-15)			0.56
ΔQoR-15	−11.50 [− 15.00 – −8.00]	−7.50 [− 10.00 – −4.00]	0.001 †
Effect size r (ΔQoR)			0.41

QoR-15 Quality of Recovery-15, p-value < 0.05 statistically significant

Effect size r: Effect size (r coefficient); r = 0.41 → Medium-to-large effect size

^* Mean ± Standard Deviation; independent samples t-test, ^† Median [interquartile range, IQR]; Mann–Whitney U test

Δ: Delta, Cohen’s d: Cohen’s d effect size coefficient; Cohen’s d = 0.56 → Corresponding to a moderate effect size

Bold entries indicate statistically significant values

Postoperative NRS scores decreased progressively over time in both groups. Median NRS values at postoperative 0, 2, 6, 12, and 24 h were 3.00 [2.00–4.00], 3.00 [2.00–3.00], 3.00 [1.25–3.00], 2.00 [1.00–2.00], and 1.50 [1.00–2.00] in the Group ESPB, respectively. Corresponding values in the Group PVB were 2.00 [2.00–3.00], 2.00 [2.00–3.00], 2.00 [1.00–3.00], 2.00 [1.00–2.00], and 1.00 [0.25–2.00], respectively (Fig. 2).

Fig. 2.

Numeric Rating Scale (NRS) and Quality of Recovery-15 (QoR-15) scores between group PVB and group ESPB

Linear mixed-model analysis demonstrated a statistically significant group × time interaction for postoperative NRS scores (χ² (4) = 18.37, p = 0.001), indicating different postoperative pain trajectories between the groups over time.

At postoperative 0 h, NRS scores were significantly higher in Group ESPB compared with Group PVB (estimated difference 0.87, 95% CI 0.33–1.40, p = 0.002). However, no significant between-group differences were observed at postoperative 2 h (estimated difference 0.40, 95% CI − 0.14–0.94, p = 0.144), 6 h (0.37, 95% CI − 0.17–0.90, p = 0.180), 12 h (− 0.10, 95% CI − 0.64–0.44, p = 0.713), or 24 h (0.07, 95% CI − 0.47–0.60, p = 0.807). Within both groups, postoperative NRS scores progressively decreased over time, consistent with expected postoperative pain resolution (Table 3).

Table 3.

Longitudinal analysis of postoperative Numeric Rating Scale (NRS) scores

Time	Group ESPB (n = 30)	Group PVB (n = 30)	ESPB − PVB Estimate	95% CI	p-value
NRS 0 h	3.00 [2.00–4.00]	2.00 [2.00–3.00]	0.87	0.33 to 1.40	0.002‡
NRS 2 h	3.00 [2.00–3.00]	2.00 [2.00–3.00]	0.40	−0.14 to 0.94	0.144‡
NRS 6 h	3.00 [1.25–3.00]	2.00 [1.00–3.00]	0.37	−0.17 to 0.90	0.180‡
NRS 12 h	2.00 [1.00–2.00]	2.00 [1.00–2.00]	−0.10	−0.64 to 0.44	0.713‡
NRS 24 h	1.50 [1.00–2.00]	1.00 [0.25–2.00]	0.07	−0.47 to 0.60	0.807‡
Linear mixed-model analysis
Time effect					0.000¶
Group × time interaction					0.001¶

p-value < 0.05 statistically significant and p-value < 0.001 = 0.000

NRS Numeric Rating Scale

‡ Pairwise between-group comparisons at each postoperative time point were obtained from the linear mixed-effects model using estimated marginal means with Bonferroni adjustment. Estimated differences and 95% confidence intervals were derived from the mixed-effects model

¶ Overall effects derived from the linear mixed-effects model including fixed effects for group, time, and group × time interaction, with patient included as a random effect. Degrees of freedom were estimated using the Kenward–Roger method

Bold entries indicate statistically significant values

Discussion

In this prospective randomized study, we compared the effects of ultrasound-guided thoracic ESPB and PVB on quality of recovery and pain control in patients undergoing VATS. Our findings demonstrated that PVB was associated with higher QoR-15 scores at 24 h postoperatively compared with ESPB. In addition, NRS scores at postoperative hour 0 were lower in the Group PVB, whereas no differences were observed between 2 and 24 h. Opioid consumption, rescue analgesia requirements, LOS, and complication rates were comparable between the groups. These findings suggest that PVB may provide modest early postoperative analgesic and recovery-related benefits; however, the clinical relevance of these differences should be interpreted cautiously.

One of the major strengths of our study is that recovery was assessed not only based on pain intensity but also using the multidimensional and validated Turkish version of the QoR-15 questionnaire. QoR-15 is a patient-centered outcome measure that evaluates multiple domains of recovery, including pain, physical comfort, emotional state, psychological support, and physical independence [11]. The similarity and near-ceiling preoperative QoR-15 scores in both groups indicate that the randomization process achieved baseline homogeneity. The difference observed at 24 h postoperatively in favor of PVB may reflect the impact of early analgesic effectiveness on patients’ perception of recovery. This finding is consistent with contemporary perioperative care approaches emphasizing that analgesic strategies in thoracic surgery should aim not only to reduce pain scores but also to improve overall recovery quality [12]. These findings are further supported by previous studies in VATS patients demonstrating a significant negative correlation between postoperative pain intensity and QoR-15 scores, indicating that higher pain levels are closely associated with poorer overall recovery [13].

Postoperative pain following thoracic surgery is multifactorial and is largely related to intercostal nerve irritation, pleural inflammation, and chest tube placement [14]. Although VATS is less invasive than thoracotomy, moderate to severe pain remains common within the first 24 postoperative hours. Effective analgesia is therefore essential not only for patient comfort but also for maintaining adequate ventilation and cough function, thereby helping to prevent pulmonary complications. Both PVB and ESPB are widely used and considered safe regional anesthesia techniques in thoracic surgery [4, 15].

Previous studies have shown that the type of surgical procedure may influence analgesic outcomes. In patients undergoing laparoscopic sleeve gastrectomy, bilateral ESPB and PVB have been reported to yield similar results in terms of QoR-15 scores, pain scores, opioid consumption, and PONV at 24 and 48 h [16]. In another randomized study conducted in thoracoscopic lobectomy, both techniques were found to improve QoR-15 scores, while analgesic outcomes and complication rates between groups tended to converge over time [17]. These findings suggest that both techniques may effectively support patient-centered recovery and analgesia, although a clear superiority of one technique over the other may not always be demonstrated. However, thoracic surgery involves unique visceral and pleural pain components, which may influence the effectiveness of segmental blocks. Indeed, meta-analytic data indicate that ultrasound-guided PVB can increase QoR-15 scores after VATS by an average of 10.48 points (MD = 10.48; 95% CI 5.33–15.64), reduce Visual Analog Scale (VAS) scores by 1.57 points (MD = − 1.57; 95% CI − 2.30 to − 0.85), and significantly decrease the incidence of PONV (OR = 0.20; 95% CI 0.08–0.51) [18].

Nevertheless, a randomized trial comparing continuous ESPB catheter analgesia with PVB catheter analgesia in minimally invasive thoracic surgery reported higher QoR-15 scores in Group ESPB at both 24 and 48 h [118 (106–134) vs. 110 (89–121); P = 0.03 and 131 (121–139) vs. 120 (111–133); P = 0.03] [19]. Similarly, in a randomized study where ESPB was combined with a serratus anterior plane block in thoracoscopic surgery, the technique was found to be superior to Group PVB in terms of QoR-15 at 24 h (ESPB+SAPB: 125 ± 8; Group PVB: 121 ± 12; p < 0.05). These findings suggest that ESPB may provide recovery outcomes comparable to PVB when combined with additional regional techniques [20]. Furthermore, a 2025 systematic review and meta-analysis reported no clinically meaningful differences between the two blocks for most outcomes, with substantial heterogeneity across studies [21]. Overall, the heterogeneous and sometimes conflicting findings in the literature suggest that the comparative efficacy of ESPB and PVB may be influenced by factors such as surgical type, technical application strategy, and the multimodal analgesia protocol employed.

Although a postoperative decline in QoR-15 scores was observed in both groups, as expected following surgery, the decrease was approximately 13–14 points in Group ESPB and about 8–9 points in Group PVB. However, the approximately 5-point between-group difference remained below the established minimal clinically important difference (MCID) of approximately 8 points reported for QoR-15 [22], suggesting limited clinical relevance despite statistical significance. Nevertheless, the moderate effect sizes observed may indicate measurable differences between groups. Another important consideration relates to the study power and interpretation of these findings. The sample size calculation was based on effect sizes derived from comparisons between PVB and control groups, whereas the present study compared two active regional anesthesia techniques, for which smaller effect sizes would be expected. This may have resulted in an overestimation of the anticipated effect size and consequently insufficient statistical power to detect clinically meaningful differences, increasing the risk of a type II error. Furthermore, the very high baseline QoR-15 scores observed in both groups, approaching the upper limit of the scale, suggest a potential ceiling effect that may have reduced the sensitivity of the instrument to detect clinically meaningful postoperative differences. In addition, the absence of a systemic analgesia-only control group limited the ability to assess the absolute benefit of regional anesthesia. Therefore, the findings should be interpreted with caution, particularly regarding their clinical significance.

The lower NRS scores observed in the Group PVB during the early postoperative period may be explained by the more rapid and predictable segmental analgesia provided by PVB. In PVB, the local anesthetic is deposited directly within the paravertebral space and spreads to the ventral and dorsal rami as well as the sympathetic chain [23]. On the other hand, ESPB involves injection within a fascial plane, and its analgesic effect depends largely on the degree and consistency of anterior spread of the local anesthetic toward the paravertebral space. Previous studies have demonstrated that paravertebral spread following ESPB may be variable, which could explain the heterogeneity observed in clinical analgesic outcomes. In contrast to PVB, which provides a more direct and relatively high-density segmental blockade due to its proximity to the spinal nerves, ESPB is generally associated with a wider but less dense distribution of local anesthetic. This difference in block characteristics may contribute to variations in the intensity and reliability of analgesia observed between techniques [24].

In our study, the local anesthetic regimens differed between groups (ESPB: high volume–low concentration; PVB: low volume–high concentration). Although the total dose was comparable, these differences may have influenced both the spread and density of the block. Interfascial plane blocks are predominantly volume-dependent, whereas PVB provides more segmental and predictable analgesia. In addition, as highlighted by Fusco et al., pharmacological factors such as systemic absorption and drug characteristics may also affect block efficacy [25]. This may partly explain the differences observed in early postoperative analgesia in our study.

Similarly, Baser et al. reported that in patients undergoing thoracotomy, PVB provided superior analgesia in the immediate postoperative period, whereas NRS scores during the subsequent 24-hour period were comparable between groups, demonstrating a temporal pain pattern consistent with our findings [26]. In a three-arm randomized study conducted by Turhan et al. in VATS patients, dynamic pain scores (VAS) at 24 h were reported to be lower in the Group PVB (p < 0.017) [27]. Pang et al. also reported in a meta-analysis that VAS scores at postoperative 12 h were significantly lower in Group PVB than in Group ESPB following thoracoscopic surgery (SMD = 1.12; 95% CI 0.42–1.81; p = 0.002), whereas no significant differences were observed at 1–2 h or 4–6 h (p > 0.05) [28]. These data suggest that PVB may offer an analgesic advantage particularly during the early postoperative phase. Additionally, in a prospective randomized trial comparing continuous ESPB catheter analgesia with surgeon-placed paravertebral catheters in minimally invasive thoracic surgery, higher QoR-15 scores were reported in Group ESPB at 24–48 h, although pain and opioid consumption outcomes did not always parallel QoR results [19]. Taken together, the pattern observed in our study—namely early NRS differences accompanied by a QoR difference at 24 h—appears consistent with existing literature.

Regarding opioid consumption, some studies have reported results favoring PVB [27–31], whereas certain meta-analyses have found no significant difference between the two techniques [16, 21, 32]. In a 2025 randomized non-inferiority trial comparing ESPB, retrolaminar block, and PVB in single-incision VATS, analgesic outcomes among blocks were largely comparable, although the authors emphasized that block selection should be individualized according to the clinical context [33]. In thoracotomy patients, 24-hour morphine consumption was reported as 16 (15–17.25) mg in the Group PVB and 19 (16–22) mg in Group ESPB, with a statistically significant difference (p = 0.012) [34]. These values correspond to approximately a 15–20% reduction in opioid consumption in morphine milligram equivalents (MME). In contrast, studies conducted in VATS patients have reported similar 24-hour sufentanyl consumption levels of approximately 43–46 µg between groups (p = 0.472) [35]. Furthermore, although a 2023 meta-analysis reported reduced analgesic consumption favoring PVB after thoracoscopic surgery (SMD = 1.27; p = 0.01), substantial heterogeneity among studies was noted [28]. This heterogeneity may be related to differences in surgical invasiveness and multimodal analgesia protocols. In our study, the similar total MME levels observed between groups may reflect the balancing effect of an effective multimodal analgesia protocol.

Although PVB has been associated with lower pain scores and reduced opioid consumption at certain time points in thoracic surgery, rescue analgesic requirements have frequently been reported to be similar between ESPB and PVB in most studies. Likewise, although variable results have been reported across different postoperative time points, most studies have not demonstrated significant differences in LOS [21, 27, 28]. Consistent with these findings, rescue analgesic requirements were similar between groups in our study. This may be explained by the limited sample size, particularly for secondary outcomes, or by the multimodal analgesia protocol attenuating potential differences between blocks. Similarly, the absence of differences in LOS may be related to multiple determinants beyond analgesia alone, including chest drain management, mobilization protocols, and institutional discharge criteria.

From a safety perspective, ESPB has been suggested to provide theoretical advantages regarding complications such as pneumothorax, hematoma, and subarachnoid spread [36]. However, pooled evidence indicates that both techniques have comparable safety profiles when performed under ultrasound guidance by experienced clinicians [37]. In our study, complication rates were similar between groups. Likewise, no significant differences in PONV were observed, consistent with previous meta-analyses [21, 28].

The observation that QoR-15 scores differed at 24 h despite similar late postoperative NRS scores suggests that recovery quality cannot be explained solely by pain intensity. Early analgesia may influence other QoR-15 domains such as sleep quality, emotional state, and perceived physical independence. This highlights the importance of patient-centered outcome measures in evaluating perioperative care quality from a broader perspective.

This study has several limitations. First, it was conducted at a single center, which may limit the generalizability of the findings. Pain was assessed only at rest, and the absence of dynamic pain evaluation (e.g., during coughing or mobilization), which plays a critical role in postoperative recovery after thoracic surgery, may have limited the comprehensive assessment of analgesic efficacy. In addition, the lack of domain-specific analysis of QoR-15 restricts understanding of which specific aspects of recovery contributed to the observed differences. Another limitation is the short follow-up period, limited to the first 24 postoperative hours; therefore, longer-term outcomes such as chronic pain and functional recovery could not be evaluated. Furthermore, the exclusion of patients undergoing more extensive procedures, such as lobectomy or pneumonectomy, may reduce the generalizability of the results.

An additional limitation relates to the use of different local anesthetic regimens between groups (ESPB: 30 mL of 0.25% bupivacaine vs. PVB: 20 mL of 0.375% bupivacaine). Although the total doses were comparable, the higher-volume/lower-concentration approach used in ESPB and the lower-volume/higher-concentration approach used in PVB may have influenced both block spread and block density, potentially acting as a confounding factor. The absence of a systemic analgesia-only control group also precludes assessment of the absolute benefit of regional anesthesia and limits interpretation of the clinical relevance of the findings. In addition, the lack of routine sensory block assessment limited confirmation of block success and may have introduced variability in analgesic outcomes, potentially affecting patient-reported measures such as QoR-15.

Finally, the study may have been underpowered to detect differences between two active techniques, as the sample size calculation was based on effect sizes derived from comparisons with control groups, thereby increasing the risk of a type II error. Additionally, differences in pain assessment methods across studies (VAS vs. NRS) may further limit comparability of the findings.

Conclusion

PVB was associated with lower early postoperative pain scores and higher QoR-15 scores at 24 h compared with ESPB in patients undergoing VATS. However, although a statistically significant difference in QoR-15 was observed, the magnitude of this difference did not reach the established MCID, indicating no clinically meaningful difference between groups. These findings suggest a modest and potentially limited clinical effect and should therefore be interpreted with caution. In addition, analgesic requirements, LOS and complication rates were comparable between the two techniques. Larger multicenter studies with longer follow-up are needed to determine whether these early findings translate into clinically meaningful long-term outcomes.

Abbreviations

PVB

Paravertebral block

ESPB

Erector spinae plane block

VATS

Video-Assisted Thoracoscopic Surgery

QoR-15

Quality of Recovery-15

ASA

American Society of Anesthesiologists

BMI

Body mass index

PCA

Patient-controlled analgesia

NRS

Numeric Rating Scale

VAS

Visual Analog Scale

LOS

Length of hospital stay

MAC

Minimum alveolar concentration

MME

Morphine milligram equivalents

MCID

Minimal clinically important difference

Authors’ contributions

The research questions were formulated, and the study was designed by OA and CKB. Data analysis was carried out by OA, CKB, and EM. The manuscript was initially drafted by OA and EM. Critical review, editing, and approval of the manuscript were performed by OA and EM. OA, CKB and EM finalized the manuscript, incorporating feedback from all authors. All authors contributed with comments and approved the final version of the manuscript.

Funding

There is no financial support or funding.

Data availability

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

This prospective randomized trial was conducted following ethical approval from the Başakşehir Çam and Sakura City Hospital Ethics Committee (KAEK/03.04.2024.245) and was registered on ClinicalTrials.gov (ID: NCT06558331). Informed consent was obtained from all patients. The clinical trial was prospectively registered on August 14, 2024. This manuscript adheres to the applicable CONSORT guidelines and the Declaration of Helsinki.

Consent for publication

Not Applicable.

Competing interests

The authors declare no competing interests as defined by BMC, nor any other interests that could be perceived to influence the results or discussion presented in this manuscript.