Efficacy of pectoral nerve II block for flap dissection-related pain following robot-assisted transaxillary thyroidectomy: a prospective, randomized controlled trial
Article information
Abstract
Background
Robot-assisted transaxillary thyroidectomy (RATT) involves extensive flap dissection, leading to significant postoperative pain. This study evaluated the efficacy of pectoral nerve II (PECS II) block in pain relief, opioid reduction, and recovery enhancement.
Methods
This prospective, randomized controlled trial included 83 patients undergoing elective RATT for thyroid conditions. Patients were assigned to the block group (n = 42) or non-block group (n = 41). Pain was assessed using the visual analog scale (VAS) at 1, 4, 24, and 48 h postoperatively. Secondary outcomes included opioid consumption and Quality of Recovery-15 (QoR-15K) scores at discharge.
Results
The PECS II block group had significantly lower VAS scores at 1 h (3.6 ± 2.5 vs. 6.3 ± 2.3, P < 0.001), 4 h (2.6 ± 2.1 vs. 4.3 ± 2.5, P = 0.002), and 24 h (2.0 ± 1.6 vs. 3.2 ± 2.0, P = 0.002). Opioid consumption was significantly lower in the block group (median: 1 [0.75, 3] vs. 3 [2, 3.5], P = 0.001). QoR-15K pain subdimension scores were higher in the block group (14.5 [12, 17] vs. 10 [8, 14], P < 0.001), while other recovery aspects were comparable.
Conclusions
The PECS II block significantly reduces pain and opioid use in RATT patients, enhancing recovery quality. This opioid-sparing approach supports multimodal pain management, ensuring safer and more comfortable postoperative recovery.
Introduction
Robot-assisted transaxillary thyroidectomy (RATT) is a modern surgical technique that achieves outcomes comparable to or better than traditional open or endoscopic procedures [1]. However, the procedure requires a deep axillary incision and extensive subcutaneous flap dissection above the pectoralis muscles, extending to the anterior neck [2,3]. The use of an external retractor, with or without CO2 insufflation, applies mechanical tension to the dissected tissues, contributing to postoperative discomfort. Up to 65% of patients experience significant chest pain for at least two days after subplatysmal flap dissection [4–6]. Despite the use of various analgesic regimens, standardized pain management protocols for robot-assisted procedures remain undefined [7–10].
Recent advances in ultrasound-guided techniques have expanded the use of myofascial plane blocks, including the pectoral nerve II (PECS II) block, for surgical analgesia. By delivering local anesthetic into the musculofascial planes, PECS II blocks avoid direct injection near critical structures such as the spinal cord, major blood vessels, and pleura [11]. As a safer alternative to central blocks, PECS II provides effective analgesia for the pectoralis, long thoracic, and thoracodorsal nerves while reducing the risks of sympathectomy. This technique is particularly beneficial for surgeries involving extensive axillary dissection [12]. A prospective study on pain management for modified radical mastectomy demonstrated that PECS II offered superior and longer-lasting pain relief compared to paravertebral blocks. Notably, no complications such as pneumothorax or local anesthetic toxicity were reported in the PECS II group, whereas one paravertebral block patient experienced intraoperative hypotension [13].
Postoperative nausea and vomiting (PONV) are common in thyroid surgery and can lead to complications such as aspiration, wound dehiscence, delayed discharge, and increased healthcare costs [14]. Open thyroidectomy, particularly in women, has PONV rates of 65%–70% under inhalational anesthesia [15]. RATT, using a gasless transaxillary approach with the Da Vinci Robotic Surgical System, may reduce PONV compared to open techniques by eliminating midline strap muscle dissection and reducing para-esophageal traction that also alleviates swallowing discomfort and voice impairment [16,17]. Additionally, RATT’s reduced opioid use—a key factor in PONV—may further support recovery [16,18]. Complementing these advantages, the PECS II block further minimizes opioid use while providing effective pain relief. By reducing perioperative opioid consumption, it indirectly mitigates opioid-induced PONV and supports efforts to enhance recovery quality, as demonstrated in the present study [19].
Our previous study demonstrated that the PECS II block effectively reduces early postoperative pain, enhances patient comfort, and lowers opioid use in RATT patients. However, its retrospective design limited generalizability [3]. To address this, we conducted a prospective, randomized controlled trial to evaluate the PECS II block’s efficacy in alleviating flap dissection pain, reducing opioid consumption, and improving early postoperative recovery in RATT patients.
Materials and Methods
Ethical considerations
This prospective, randomized controlled trial was approved by the Ethics Committee of Seoul St. Mary’s Hospital (KC22EISI0542) on September 29, 2022, and conducted in accordance with the Declaration of Helsinki (2013). The trial was registered with the Clinical Research Information Service (CRIS) of the Republic of Korea (registration number: KCT0008305, http://cris.nih.go.kr) and ClinicalTrials.gov (registration number: NCT06101043, https://clinicaltrials.gov). All participants provided written informed consent prior to enrollment that took place between November 16, 2022, and May 22, 2023. This study adheres to the Consolidated Standards of Reporting Trials (CONSORT) 2010 Statement and the CONSORT PRO Extension guidelines [20].
Study population
Inclusion criteria included adults aged 19–60 years undergoing elective RATT for stage T1 or T2 thyroid cancer with tumors ≤ 4 cm or benign nodules verified by ultrasonography. Exclusion criteria included a history of neck surgery (including lateral cervical lymph node dissection), pregnancy, uncontrolled diabetes, chronic kidney failure, Graves’ disease, chronic alcoholism, preoperative vocal cord paralysis, BMI < 18.5 kg/m2 or > 35 kg/m2, recent participation in another trial, or any condition preventing study participation or completion of questionnaires.
A total of 90 patients were assessed for eligibility. Seven patients were excluded due to the following reasons: history of neck surgery (n = 3), obesity with a BMI > 35 kg/m2 (n = 3), and lateral cervical lymph node dissection required during surgery (n = 1). A total of 84 patients were randomized into two groups: the block group (n = 42) and the non-block group (n = 42). One patient in the non-block group discontinued the intervention, and the remaining 83 patients were included in the final analysis (Fig. 1).
CONSORT flow diagram of the study. BMI: body mass index, PECS II: pectoral nerve II.
Randomization and blinding
Patients were evenly randomized into either the block or non-block group using a web-based random number generator for stratified block randomization (www.random.org). Patient allocation was managed by a research nurse who was not involved in patient treatment. Group assignments for enrolled patients were determined by opening sequentially numbered, opaque envelopes.
Blinding was maintained throughout the study. Patients and surgeons were blinded to group assignments, as were the medical staff responsible for postoperative care and outcome evaluation in the PACU and ward. The anesthesiologist administering the PECS II block was aware of the group assignments; however, this individual was not involved in postoperative care or the assessment of postoperative outcomes.
Surgery and general anesthesia
The RATT procedure and anesthetic techniques were previously described [2,3]. The surgery was performed using the da Vinci single-port robotic system in three stages. Initially, a flap dissection was conducted from the axilla to the thyroid gland, exposing the pectoralis major muscle, followed by dissection to expose the sternocleidomastoid muscle and the strap muscles surrounding the thyroid gland. After completing this step, the robotic arms were positioned, and the surgeon conducted the operation from the console, adhering to standard RATT protocols.
General anesthesia was induced with intravenous propofol (2–2.5 mg/kg), rocuronium (0.6 mg/kg), and fentanyl (1–2 µg/kg). Maintenance of anesthesia was achieved using desflurane (4%–6%) and a continuous infusion of remifentanil (0.1–0.2 µg/kg/min). Patient monitoring included electrocardiography, pulse oximetry, non-invasive blood pressure, bispectral index (target range: 40–60), end-tidal CO2 (maintained at 35–40 mmHg), and esophageal temperature. To prevent PONV, palonosetron (0.075 mg) and dexamethasone (8 mg) were administered intravenously at the end of surgery. Neuromuscular blockade was reversed with sugammadex (2–4 mg/kg) under 100% oxygen ventilation to ensure optimal recovery. Additional oxygenation was provided until the patient achieved complete neuromuscular recovery and stable respiratory function.
When postoperative pain exceeded 5 cm on the visual analog scale (VAS), classified as moderate to severe pain (0 cm indicating no pain and 10 cm indicating the worst pain), rescue analgesics were administered in the post-anesthesia care unit (PACU) and the ward. The rescue analgesic consisted of 50 µg of intravenous fentanyl, provided by attendants who were not involved in the study [21,22]. To accurately evaluate the analgesic efficacy of the PECS II block, no preemptive pain medications were administered during the perioperative period. Postoperative pain management on the ward excluded routine use of PCA or scheduled analgesics, allowing for an isolated assessment of the block’s effectiveness. Instead, rescue analgesics were administered as needed, based on patient-reported pain severity, to ensure adequate pain control. Fentanyl (50 µg) was exclusively used as the rescue analgesic, enabling a precise evaluation of the block’s impact on opioid consumption.
PECS II block in the operating theater
As described in our previous study [3], an experienced anesthesiologist performed all pectoral nerve blocks immediately following the induction of general anesthesia (Fig. 2). Patients were positioned supine, and the infraclavicular and axillary regions were aseptically prepared. A 21-gauge echogenic needle, 85 mm in length (Vygon), was inserted obliquely at the second and third ribs beneath the clavicle under ultrasound guidance (Venue Go; GE HealthCare) (Fig. 3). Using a medial in-plane approach with a 12L-RS Wideband Linear Array Probe (GE HealthCare), the anesthesiologist injected 20 ml of 0.375% w/v ropivacaine (Mitsubishi Tanabe Pharma) between the pectoralis minor and serratus anterior muscles at the level of the third rib (Fig. 4). The needle was then repositioned, and an additional 20 ml of 0.375% w/v ropivacaine was injected between the pectoralis major and minor muscles. The block’s efficacy and safety were verified ultrasonographically, ensuring adequate spread of the local anesthetic and the absence of complications such as intravascular injection, pneumothorax, or nerve injury. The injection was administered slowly, with intermittent aspiration to prevent vascular puncture or systemic toxicity. All procedures adhered to strict aseptic techniques to minimize infection risk. No adverse events were observed during or after the block administration in the block group, confirming its safety and feasibility in the perioperative setting. Additionally, no complications related to standard perioperative care were reported in the non-block group.
Targeted analgesic coverage area of the Pectoral Nerve II block, illustrating the flap dissection procedure involving the pectoral and axillary regions.
Needle advancement along the anterior axillary line during the Pectoral Nerve II block procedure.
Ultrasound-guided Pectoral Nerve II block technique. (A) Ultrasound anatomical view showing the pectoralis major, pectoralis minor, and serratus anterior muscles above the third rib. (B) Needle insertion point between the pectoralis minor and serratus anterior muscle layers. (C) Needle placement between the pectoralis major and pectoralis minor muscle layers.
Pain outcomes
The primary outcome of this study was the level of postoperative pain, assessed using the VAS at 1, 4, 24, and 48 hours after surgery. Secondary outcomes included the consumption of rescue opioid analgesics, specifically fentanyl, in the PACU and the ward. A research nurse, blinded to group assignments, recorded the pain scores and tracked opioid use to ensure accurate and unbiased evaluation of pain management and medication usage.
Recovery outcomes
The quality of postoperative functional recovery was evaluated on the day of discharge using the Korean version of the Quality of Recovery-15 (QoR-15K) questionnaire [23]. This assessment was conducted by a research nurse blinded to the group assignments to ensure unbiased results. The QoR-15K questionnaire, with a maximum score of 150 points, is a validated tool to assess postoperative recovery. Higher scores reflect superior recovery across multiple domains, including physical comfort, emotional well-being, and pain management. The QoR-15K includes five dimensions of recovery: physical comfort (items 1, 2, 3, 4, and 13), physical independence (items 5 and 8), psychological support (items 6 and 7), emotional state (items 9, 10, 14, and 15), and pain (items 11 and 12). The score for each dimension was calculated by summing the scores of the corresponding items, providing a comprehensive evaluation of recovery quality.
Clinical variables
Patient demographics, including age, sex, height, weight, and BMI, were recorded. Additionally, thyroid pathology characteristics were documented, such as the extent of the operation, tumor size and multiplicity, the presence of minimal extrathyroidal extension, lymph node involvement, and tumor-node-metastasis (TNM) staging. Postoperative complications were categorized as either procedure-related (e.g., infection, vascular injury, hematoma, and pneumothorax) or local anesthetic-related (e.g., seizure, arrhythmia, dizziness, and sedation).
Statistical analyses
In our previous RATT study [3], the average 24-hour postoperative pain scores, measured using the VAS, were 2.6 in the block group and 3.5 in the non-block group. Based on a statistical power of 80%, a type I error threshold of 0.05, and an observed standard deviation (SD) of 1.45 cm, the sample size calculation determined a minimum requirement of 41 patients per group. To account for an anticipated dropout rate of approximately 10%, based on the exclusion of seven out of 69 eligible patients in our prior study, we enrolled a total of 90 patients to ensure robust and reliable trial results.
Statistical analyses were performed by a blinded analyst using an intention-to-treat approach. Continuous variables were tested for normality with the Shapiro–Wilk test and are presented as means ± SDs or medians with interquartile ranges, depending on their distribution. Normally distributed data were compared using Student’s t-tests, while non-normally distributed data were analyzed with Mann–Whitney U tests. Changes in postoperative VAS pain scores over time were evaluated with repeated-measures ANOVA, and post-hoc comparisons of VAS scores at 4, 24, and 48 hours against the baseline at 1 hour postoperatively were conducted using paired t-tests. The frequencies of rescue opioid administration in both the PACU and the ward were compared using Wilcoxon signed-rank tests. Categorical variables are presented as frequencies (percentages), and comparisons between the groups were performed using Pearson’s chi-square or Fisher’s exact tests, as appropriate. Statistical significance was defined as a two-sided P value of 0.05. All analyses were conducted using SAS (Version 8.4, SAS Institute Inc.), and graphical representations were generated using Microsoft Excel.
Results
Demographic findings
The clinicopathological characteristics of the participants are summarized in Table 1. The mean age of the study population was 41.5 ± 10.6 years, with 88% (n = 73) female. The majority of the patients (89.2%, n = 74) underwent lobectomy, while 10.8% (n = 9) underwent total thyroidectomy. The most common pathology was papillary thyroid carcinoma, diagnosed in 90.4% (n = 75) of cases, with a mean tumor size of 1.0 ± 0.8 cm. Most participants (96%, n = 72) had TNM stage I disease. There was a significant difference in the extent of surgery between the block and non-block groups (P = 0.029), with a higher proportion of total thyroidectomies in the block group (19.1% vs. 2.4%). However, other baseline characteristics, including age, sex, BMI, tumor size, multifocality, extrathyroidal extension, and lymph node involvement, were comparable between the groups.
Baseline Clinicopathological Characteristics of the Study Population
Robot-assisted total thyroidectomy required significantly more time than robot-assisted lobectomy (183.7 ± 2.8 min vs. 164.4 ± 1.9 min, P < 0.001). However, in this study, the overall surgery duration was similar between the groups (165.1 ± 4.0 min vs. 167.8 ± 7.8 min, P = 0.053).
Postoperative pain and opioid use outcomes
Postoperative pain, assessed using VAS scores, was significantly lower in the block group compared to the non-block group at 1, 4, and 24 hours after surgery (Table 2, Fig. 5). At 1 hour in the PACU, the block group had a mean VAS score of 3.6 ± 2.5, markedly lower than the 6.3 ± 2.3 recorded in the non-block group (P < 0.001). Similar trends were observed at 4 and 24 hours in the ward, where the block group consistently reported lower pain levels (4 h: 2.6 ± 2.1 vs. 4.3 ± 2.5, P = 0.002; 24 h: 2.0 ± 1.6 vs. 3.2 ± 2.0, P = 0.002). By 48 hours postoperatively, the difference in pain scores between the groups was no longer statistically significant (1.3 ± 1.5 vs. 1.8 ± 1.2, P = 0.147).
Postoperative Pain and Opioid Outcomes
Comparative analysis of postoperative Visual Analog Scale (VAS) pain scores at 1, 4, 24, and 48 h after surgery. Data are presented as mean ± SD. P < 0.05 compared with the values in the post-anesthesia care unit (1 h).
Opioid use also differed significantly between the groups. During the entire hospital stay that encompassed the 48 hours following surgery, the block group required significantly fewer rescue opioid administrations, with a median of 1 (0.75, 3) compared to 3 (2, 3.5) in the non-block group (P = 0.001). The most notable difference occurred during the first hour in the PACU, where the block group required fewer rescue opioid administrations (0 [0, 1]) compared to the non-block group (1 [1, 1], P < 0.001). This pattern persisted in the first 1 to 4 hours postoperatively, with the block group showing a lower median demand (0 [0, 1] vs. 1 [1, 1.5], P < 0.001). While both groups exhibited a decrease in opioid usage over the first 24 hours, patients in the block group required significantly less opioids compared to the non-block group.
The distribution of rescue opioid use differed significantly between the groups (Fig. 6). In the block group, 64.3% of patients required minimal or no rescue opioids (0–1 administration), compared to only 21.9% in the non-block group. Conversely, 48.8% of non-block patients needed three or more administrations, compared to 19.1% in the block group. Notably, extreme opioid use (five or more administrations) was more frequent in the non-block group (9.8%) than in the block group (2.4%). These findings highlight the opioid-sparing effect of the PECS II block.
Distribution of rescue opioid administrations in the block and non-block groups.
Outcomes of the QoR-15K questionnaire
The QoR-15K scores for the pain subdimension were significantly higher in the block group compared to the non-block group (median: 14.5 [12, 17] vs. 10 [8, 14], P < 0.001; Table 3). Within the pain subdimension, scores for moderate pain (Q11) and severe pain (Q12) were also significantly lower in the block group (moderate pain: 5.5 [5, 8] vs. 5 [3, 7], P = 0.008; severe pain: 9 [7, 10] vs. 7 [4, 10], P = 0.001). These results highlight the improved pain outcomes associated with the use of the PECS II block.
Outcomes of the QoR-15K Questionnaire
Other subdimensions, including physical comfort, emotional status, psychological support, and physical independence, showed no significant differences between the two groups. The global QoR-15K scores were also similar, with medians of 119 [102, 136] in the block group and 116 [94, 129] in the non-block group (P = 0.242). This suggests that while the PECS II block provides superior pain management, its effects on broader aspects of postoperative recovery are comparable to standard care.
Postoperative complications
No complications related to the PECS II block procedure, such as pneumothorax, vascular puncture, leakage of local anesthetic into the surgical field, or local anesthetic systemic toxicity (LAST), were observed in the block group during the postoperative period. Furthermore, no adverse reactions, including arrhythmia or seizures, occurred following the administration of local anesthetics. Additionally, both groups were free of significant postoperative complications commonly associated with thyroid surgery, such as infection, hematoma, or airway compromise.
Furthermore, additional antiemetics were not required in either group, reflecting effective perioperative management and a low incidence of PONV. All patients were discharged on the second postoperative day without any complications necessitating further treatment or intervention, underscoring the safety and feasibility of the PECS II block as an adjunct to perioperative care.
Discussion
This trial confirmed that the PECS II block significantly reduced surgical site pain on the first postoperative day and decreased opioid use in the PACU for RATT patients. While overall QoR-15K scores were similar between the groups, the block group reported higher pain subdimension scores, demonstrating its effectiveness in pain management. These findings highlight the PECS II block’s role in enhancing patient comfort, reducing opioid-related side effects, and supporting multimodal recovery protocols for RATT.
The primary advantage of RATT is its ability to minimize scarring by relocating the incision from the visible neck to the axillary region, enhancing cosmetic outcomes and patient satisfaction. Beyond aesthetics, RATT is a safe and effective oncologic procedure [4,24–26]. However, postoperative pain in the anterior chest and axillary regions remains a challenge [2,6,24]. Potential causes include extensive tissue dissection, thermal effects from cautery, and retractor-induced strain that may contribute to nerve damage, neuropathic pain, or hyperalgesia [27,28]. While reducing retractor pressure through deep muscle relaxation has been suggested to mitigate pain, this hypothesis remains untested [29]. Nonopioid analgesics such as nefopam, ketamine, pregabalin, and paracetamol have been explored for RATT pain management, but their effectiveness often requires high doses or continuous infusions, increasing the risk of systemic side effects like dizziness and sedation [7–10].
The PECS II block delivers local anesthetic at two key anatomical sites. The first injection, between the pectoralis major and minor muscles, blocks the lateral and medial pectoral nerves. The second, between the pectoralis minor and serratus anterior muscles, targets the axillary and intercostal nerves (T2–T6) for broader analgesia [11,30]. Studies suggest that this technique may also anesthetize adjacent nerves, including the long thoracic and thoracodorsal nerves, further enhancing its effectiveness [31,32]. Additionally, lateral injections at the PECS I block site can improve coverage of the upper intercostal nerves, particularly at the third rib level [11].
The precise anatomical targeting of the PECS II block provides effective analgesia for regions affected by RATT flap dissection [11,30–32]. Its efficacy has been demonstrated in various surgeries, including robotic nipple-sparing mastectomies, where intraoperative administration significantly reduced pain scores and fentanyl use by 63% within 24 hours [33]. Similarly, in robotic mitral valve surgery, ultrasound-guided PECS II blocks lowered intraoperative opioid use by 18% and postoperative opioid consumption by 30% compared to paravertebral blocks [34]. Effective perioperative pain control enhances patient comfort and recovery [35,36], particularly in the PACU, where early pain control minimizes opioid use. Studies suggest that superior early pain control is associated with improved recovery scores, such as higher QoR-40 ratings [37]. However, the relationship between pain relief and overall recovery varies depending on the assessment metric. In our study, the PECS II block improved pain subdimension scores in the QoR-15K questionnaire and reduced opioid consumption, but it did not significantly impact overall QoR-15K scores. This suggests that factors beyond pain relief, such as emotional well-being and physical independence, may have a greater influence on global recovery outcomes.
Our study did not specifically assess rebound pain or its direct relationship with the diminishing effect of the PECS II block. However, we observed that patients in the block group used more opioids after 4 hours postoperatively in the ward than in the PACU, despite their overall opioid consumption being lower than that of the non-block group. This suggests that the analgesic effects of PECS II blocks that typically last 4–8 hours with agents like lidocaine and ropivacaine [33,34,38] may not provide sustained relief beyond the early postoperative period. Rebound pain—a resurgence of discomfort as the nerve block wears off—is a known challenge in postoperative pain management. This occurs when the block ceases before sufficient healing has occurred, leading to an acute increase in pain intensity [39]. A meta-analysis of breast cancer surgeries found that the PECS II block significantly reduced opioid use (mean reduction: 13.64 mg in oral morphine equivalents (95% CI [−21.22 to −6.05], P < 0.01), and delayed the first analgesic request by an average of 5 hours compared to systemic analgesia alone. Additionally, when compared to thoracic paravertebral blocks in thoracic and breast surgeries, the PECS II block demonstrated similar efficacy in pain relief and opioid reduction within the first 24 hours [40]. While further research is needed to fully characterize the duration and intensity of flap dissection pain in RATT—that is inherently minimally invasive [41]—our findings suggest that the PECS II block provides effective pain control and reduces opioid reliance. However, addressing rebound pain requires a multimodal approach. Strategies such as administering oral or intravenous non-opioid analgesics as the block wears off and using long-acting local anesthetics like liposomal bupivacaine or dexamethasone adjuvants may prolong analgesia and ensure smoother pain control during recovery [42].
The analgesic effects of fascial plane blocks, including the PECS II block, can vary due to factors such as suboptimal sensory blockade, anatomical differences, local anesthetic properties, and technical nuances [34,43,44]. To enhance efficacy and consistency, our study used 20 ml of local anesthetic in both the pectoralis major-minor and pectoralis minor-serratus anterior planes. This approach aimed to optimize anesthetic diffusion to the medial and lateral pectoral nerves, ensuring effective analgesia for the anterior chest wall that undergoes extensive dissection in RATT. While conventional practice often employs lower volumes, such as 10 ml, previous findings suggest that larger volumes improve coverage in broader surgical areas [3,11,44]. Despite the increased volume, one patient required unusually high opioid use postoperatively, possibly due to anatomical variations, local anesthetic properties, or technical factors, even though all blocks were performed by a single experienced anesthesiologist. This highlights the importance of anatomical precision and technique in achieving consistent outcomes. Fascial plane blocks rely on proper anesthetic dispersion within the targeted plane, and any deviations from the optimal conditions may compromise effectiveness [45]. Our study demonstrated that the anesthetic volume used remained within safe limits, avoiding complications such as LAST [46]. However, further research is needed to refine volume optimization strategies for extensive flap dissection. The absence of adverse events and the block’s effectiveness in providing adequate pain coverage reinforce its safety and feasibility as a tailored pain management strategy for RATT patients.
Our findings showed no significant differences between the block and non-block groups in QoR-15K subdimensions related to complications such as swallowing discomfort and nausea/vomiting. This may reflect advancements in robotic surgical techniques that minimize tissue trauma compared to open approaches [41]. While complications of the PECS II block are rare, they can include infection, arterial injury, hematoma, pneumothorax, and local anesthetic toxicity, potentially leading to severe outcomes like seizures or arrhythmias [47]. Additionally, transversus plane blocks have been linked to elevated plasma anesthetic levels, particularly in patients with cardiac or renal dysfunction, multiple injections, or even in healthy individuals [38]. Poor technique or inadequate sterility during block administration may also increase the risk of site infections, vascular injuries, or other complications [48]. However, these risks can be minimized with ultrasound guidance and administration by experienced anesthetists. Ultrasound-guided blocks improve safety by ensuring precise needle placement, preventing overdosing, and reducing the need for repeated injections, thereby enhancing both efficacy and patient outcomes.
This study has several limitations. First, it focused solely on RATT, limiting the generalizability of findings to other surgical procedures. Additionally, the sample size and patient demographics may affect broader applicability. The PECS II block’s efficacy was not assessed before surgery, as it was administered after general anesthesia induction to enhance comfort and maintain blinding that may influence effectiveness evaluations. Although a sham block was considered to reduce bias and directly assess analgesic coverage, it was excluded due to ethical concerns, as sham procedures carry risks such as vascular puncture, organ damage, pneumothorax, and nerve injury [49]. While no cases of local anesthetic leakage into the surgical field were observed, this remains a potential concern with regional blocks near surgical sites. Careful administration and ultrasound guidance are essential to mitigate this risk, and further studies could explore additional preventive measures. Postoperative pain was assessed at 1, 4, 24, and 48 hours, but intermediate time points (e.g., 8 or 12 hours) were not included. Future studies could incorporate more frequent assessments for a detailed pain progression analysis. Additionally, postoperative pain locations were not recorded, limiting insights into the block’s targeted analgesic effects. The short follow-up period also prevents evaluation of long-term outcomes, including sustained pain relief and opioid use. Addressing these limitations in future research will help refine the understanding of the PECS II block’s efficacy and safety across diverse surgical contexts.
In conclusion, the PECS II block is an effective analgesic strategy for RATT patients undergoing extensive pectoral region flap dissection. It significantly reduces postoperative pain and opioid consumption, enhancing physical comfort and minimizing opioid-related risks. While this study evaluated the standalone efficacy of the PECS II block, findings suggest its potential role in multimodal perioperative pain management, particularly for complex RATT procedures. Although overall QoR-15K scores did not differ significantly between the groups, the PECS II block provided superior pain control, as reflected in the pain subdimension of the QoR-15K. These results highlight its value in postoperative pain management and opioid reduction. Further research is needed to refine its integration into multimodal analgesia, assess its broader impact on recovery, and optimize patient-centered care.
Acknowledgements
The authors wish to acknowledge the financial support of the Catholic Medical Center Research Foundation in the program year 2022. Statistical consultation was supported by the Department of Biostatistics of the Catholic Research Center.
Notes
Funding
None.
Conflicts of Interest
No potential conflict of interest relevant to this article was reported.
Data Availability
All data generated or analyzed during this study are included in this published article.
Author Contributions
Min Suk Chae (Conceptualization; Data curation; Formal analysis; Investigation; Methodology; Project administration; Resources; Software; Supervision; Validation; Visualization; Writing – original draft; Writing – review & editing)
Kwangsoon Kim (Conceptualization; Data curation; Formal analysis; Funding acquisition; Investigation; Methodology; Project administration; Resources; Software; Supervision; Validation; Visualization; Writing – original draft; Writing – review & editing)