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Evaluation of ultrasound-guided rhomboid intercostal nerve block for postoperative analgesia in breast cancer surgery: a prospective, randomized controlled trial
  1. Başak Altıparmak1,
  2. Melike Korkmaz Toker1,
  3. Ali Ihsan Uysal2,
  4. Özcan Dere3 and
  5. Bakiye Uğur1
  1. 1 Anesthesiology, Muğla Sıtkı Koçman University, Muğla, Turkey
  2. 2 Anesthesiology, Muğla Sıtkı Koçman University Training and Research Hospital, Muğla, Turkey
  3. 3 General Surgery, Muğla Sitki Koçman University, Muğla, Turkey
  1. Correspondence to Dr Başak Altıparmak, Anesthesiology, Mugla Sitki Kocman Universitesi, Muğla 48000, Turkey; basak_ugurlu{at}yahoo.com

Abstract

Background and objectives Mastectomy has many potential sources of pain. Rhomboid intercostal block (RIB) is a recently described plane block. The primary hypothesis of the study is that ultrasound-guided RIB combined with general anesthesia would accelerate global quality of recovery scores of patients following mastectomy surgery. Secondary hypothesis is that RIB would reduce postoperative opioid consumption, pain scores, and the need for rescue analgesia.

Methods Patients aged between 18 and 70 years, with American Society of Anesthesiologists physical status I–II and scheduled for an elective unilateral modified radical mastectomy surgery with axillary lymph node dissection were enrolled to the study. Following endotracheal intubation, patients were randomly allocated into two groups. Patients in the first group (group R) received ultrasound-guided RIB with 30 mL 0.25% bupivacaine. In the control group (group C), no block intervention was applied. All patients received intravenous dexamethasone 8 mg, dexketoprofen trometamol 50 mg intraoperatively and tramadol 1 mg/kg 30 min before the end of surgery for postoperative analgesia. All patients received intravenous morphine patient-controlled analgesia device at the arrival to the recovery room.

Results The descriptive variables of the patients were comparable between group R and group C. Mean quality of recovery-40 score at 24 hours was 164.8±3.9 in group R and 153.5±5.2 in group C (mean difference 11.4 (95% CI 8.8 to 13.9; p<0.001). At 24th hour, median morphine consumption was 5 mg (IQR 4–7 mg) in group R and 10 mg (IQR 8–13 mg) in group C, p<0.001. Intraoperative fentanyl administration, pain scores and the need for rescue postoperative analgesia was similar between groups.

Conclusions In the current study, ultrasound-guided RIB promoted enhanced recovery and decreased opioid consumption after mastectomy surgery.

Trial registration number ACTRN12619000879167.

  • acute pain
  • interventional pain management
  • postoperative pain
  • ultrasound in pain medicine
  • pain outcome measurement

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Introduction

Postoperative pain is a significant concern following modified radical mastectomy (MRM) surgery.1 Removal of the pectoralis major fascia and stretching of the pectoralis muscles for a better surgical access are likely to cause perioperative myofascial pain.2 Moreover, placement of drains may contribute to pain in the postoperative period. In addition to branches of the intercostal nerves, the pectoral, thoracodorsal and long thoracic nerves may also be involved in the perioperative pain following radical mastectomy surgery with axillary involvement.1 Unfortunately, previous studies have reported that acute postoperative pain is highly associated with development of chronic pain.3 4

Rhomboid intercostal block (RIB) was first described by Elsharkawy et al 5 in 2016. Following the injection of local anesthetic into the interfascial plane between rhomboid major and intercostal muscles, the block provides analgesia for both the anterior and posterior hemithorax. RIB has the advantage of easily applicable technique and the injection site is away from the surgical area. Moreover, the block was reported to provide analgesia over 6–7 segments with a single injection.6 In the current literature, there are limited number of cases reporting the usage of RIB for breast surgery,7–9 and there are no randomized controlled trials evaluating the effect of RIB on postoperative pain or quality of recovery following breast cancer surgery.

In this prospective trial, our primary hypothesis is that ultrasound-guided RIB combined with general anesthesia would provide clinically meaningful increase in global quality of recovery scores of patients following breast cancer surgery compared with patients who received no block intervention. Our secondary hypothesis is that RIB would reduce postoperative opioid consumption, pain scores and the need for rescue analgesia.

Materials and methods

Participants and design

The study was designed as a single-center, prospective, randomized, controlled, double-blinded trial. All patients signed written informed consents both for the block procedure and enrollment to the study. Patients aged between 18 and 70 years, with American Society of Anesthesiologists (ASA) physical status I–II and scheduled for an elective unilateral MRM surgery with axillary lymph node dissection were screened for enrollment to the study. All included patients completed a quality of recovery-40 (QoR-40) test during the preoperative assessment. The exclusion criteria were patients with coagulation disorder, chronic opioid use, psychological disorder, known allergy to study drugs, history of previous mastectomy or other thoracic surgery, body mass index (BMI) ≥35 kg/m2, inability to use patient-controlled analgesia (PCA) device and surgical time >150 min.

Anesthesia application

A standard monitoring with electrocardiography, non-invasive blood pressure, peripheral oxygen saturation and bispectral index (BIS) monitoring was applied to all patients in the operating room (OR). The first heart rate and mean arterial pressure (MAP) were recorded as the baseline (0th min) measurement. Following placement of a 22-gage intravenous line, all patients received 15 mL k/gh intravenous isotonic saline infusion. General anesthesia and surgical technique were the same for all patients; anesthesia was induced with intravenous propofol 2–3 mg k/g, fentanyl 1.5 μg k/g and rocuronium bromide 0.6 mg k/g. Endotracheal intubation was performed when the BIS score was between 40 and 60. Maintenance of anesthesia was provided with 4%–6% end-tidal desflurane in 3 L of 40% O2 and 60% N2O mixture. The OR anesthesiologist titrated minimum alveolar concentration of desflurane targeting a BIS value between 40 and 60. Intravenous fentanyl 0.5 mcg k/g was applied when heart rate or MAP increased >20% of baseline measurements. All patients received intravenous ondansetron 4 mg, dexamethasone 8 mg, dexketoprofen trometamol 50 mg and tramadol 1 mg k/g 30 min before the end of surgery for postoperative nausea prophylaxis and multimodal analgesia. Inhaled anesthetic agents were stopped by the end of skin closure. All patients received intravenous atropine 0.01 mg k/g and neostigmine 0.05 mg k/g for the reversal of the neuromuscular blockage. Following successful extubation, patients were transferred to the postoperative recovery room.

Patient grouping and randomization

After the endotracheal intubation, the patients were randomly allocated into two groups. Patient grouping was based on a computerized randomization table created by a researcher who was not involved in the study. The researcher assigned a random ID to each patient involved in the study and each ID was sealed in opaque envelopes. All patients were blinded to the group allocations. A blinded anesthesiologist (AIU) used the patient ID while collecting data postoperatively in the surgical ward.

Application of block intervention

Following endotracheal intubation, patients in the first group (group R) were positioned in lateral decubitis with the involved breast lying superiorly. The ipsilateral arm was adducted across the chest to move the scapula laterally. A rhomboid intercostal block was performed as described previously when the targeted space opened up.5 A high-frequency (6–12 MHz) linear ultrasound probe (Fujifilm Sonosite, Bothwell, USA) was placed medial to the medial border of the scapula in oblique sagittal plane (figure 1). The ultrasound landmarks, trapezius muscle, rhomboid muscle, intercostal muscles, pleura and lung were identified. Under aseptic conditions, an 80 mm 21-gage needle was inserted in the plane view of the ultrasound probe at the level of T5. A single injection of 30 mL 0.25% bupivacaine was applied into the interfascial plane between the rhomboid major and intercostal muscles. The spread of local anesthetic solution under the rhomboid muscle was visualized by ultrasonography (figure 2). All block procedures were performed by the same anesthesiologist (BA) who had experience of RIB block in over 30 cases before the study. Then the patient was positioned in supine position. In the control group (group C), no block intervention was applied.

Figure 1

Placement of ultrasound-probe for performance of rhomboid intercostal block.

Figure 2

The landmarks of rhomboid intercostal block and local anesthetic injection under ultrasound view.

Analgesia protocol, evaluation of pain and sensorial block

All patients received intravenous PCA at the arrival to the recovery room. The PCA device administered 1 mg bolus dose of morphine with a 20 min lock-time and there was no basal infusion. Another blinded anesthesiologist (AIU) conducted pain assessments during coughing at the postoperative 15th min and 30th min by using the 11-point Numerical Rating Scale (NRS), which ranges from ‘0’ (meaning ‘no pain’) to ‘10’ (meaning ‘worst pain imaginable’). The patients were sent to the surgical ward at the end of the 30th min. In the surgical ward, patients were assessed again at the postoperative 1st hour, 2nd hour, 6th hour, 12th hour and 24th hour. If NRS score was ≥4, patients received intravenous dexketoprofen 50 mg as rescue analgesic.

Outcome measures

The primary outcome measure of the study was the global quality of recovery score which was assessed at the postoperative 24th hour using the Turkish version of 40-item quality of recovery questionnaire (QoR-40). This questionnaire comprises a total of 40 questions under five dimensions of health: 9-item emotional status, 12-item physical comfort, 7-item psychological support, 5-item physical independence and 7-item pain.

The secondary outcome measures were total postoperative morphine consumptions and rescue analgesic requests in the first 24 hours and NRS scores of patients at different time-points. In addition to these measures, intraoperative fentanyl need, postoperative nausea and vomiting (PONV) and block-related complications such as pneumothorax, bleeding, allergy, local anesthetic toxicity were also recorded.

Sample size

The sample size of the study was calculated using the G*Power program (V.3.1.9). We conducted a pilot study with 10 patients in our clinic. According to a previous study,10 a difference of 10 points between QoR-40 scores of two groups was accepted as clinically important. The mean of QoR-40 scores of the pilot study was 151.6 points with SD=7.57. Assuming α error=0.05 (two-tailed), β error=0.2 with a power of 0.80, at least 9 participants were needed per each group and 18 in total. Considering a high chance of dropout and the complexity of the tests which will be used, we decided to include 30 patients in each group with a power of 0.95, α error= 0.01 (two-tailed).

Statistical analysis

The shapes of the distributions of the variables in this study were assessed by using Shapiro-Wilk test, whether the observation is normal or skewed. In cases where the test results have indicated that the data were normally distributed, then data were detailed with mean± SD, and analyzed by an independent-samples t-test to compare group-wise differences (group R vs group C) on the outcome parameters (age, height, weight, BMI, pre-QoR-40 score, operation time, QoR-40 score, physical comfort, emotional status, physical independence, psychological support, pain). For the continuous data which yielded the non-parametric dispersion was detailed with median and IQR, and analyzed with Mann-Whitney U test to observe the group-wise differences (between group R and group C) on morphine consumption at 24 hours, postoperative rescue analgesic request, intraoperative fentanyl need, NRS at 15–30 min/1–2 hours/6–12 hours/24 hours. Pearson’s χ2 test was used to compare the difference between group R/C and ASA I/II. Statistical analyses were conducted using SPSS V.25 (SPSS, Chicago, Illinois, USA). P values <0.05 were considered to be significant for the tests results presented.

Results

Sixty-two female patients were screened for eligibility to participate in the study. Sixty patients were equally allocated into the study groups. Two patients in group R and one patient in group C were excluded due to mechanical problems with the PCA device and another patient in control group was excluded due to failure to complete the QoR-40. Finally, data of 56 patients were analyzed. The Consolidated Standards of Reporting Trials flow chart is shown in figure 3. The descriptive variables of the patients were comparable between group R and group C (table 1).

Table 1

The assessment of descriptive variables of the groups (mean±SD)

Figure 3

Consolidated Standards of Reporting Trials flow diagram of the trial. PCA, patient-controlled analgesia; QoR-40, 40-item quality of recovery questionnaire.

There was a significant difference between the mean global QoR-40 scores of the groups. Mean QoR-40 score was 164.8±3.9 in group R and it was 153.5±5.2 in group C; mean difference 11.4 (95% CI 8.8 to 13.9). Scores of all QoR-40 dimensions (except psychological support) differed statistically between groups. The results of global and dimension QoR-40 scores are summarized in table 2.

Table 2

Global and dimension QoR-40 questionnaire score at 24th hour

At 24th hour, total morphine consumption was 5 mg (IQR 4–7 mg) in group R and 10 mg (IQR 8–13 mg) in group C. The difference was significant (p<0.001). Postoperative rescue analgesic requests and intraoperative fentanyl need were comparable between group R and group C. Median intraoperative fentanyl need was 75 μg (IQR 75–100) and postoperative rescue analgesic need was 0 (IQR 0–0) in both groups (p=0.224 and 0.129, respectively). Median NRS scores were under four at all time-points in both groups. There was no difference in NRS scores between groups except postoperative 12th hour (table 3).

Table 3

Postoperative Numerical Rating Scale scores of patients among groups

The incidence of PONV recorded for rhomboid group was 7.4% (presence 2 and absence 25), for control group was 22.2% (presence 6 and absence 21) and in overall 14.8% considering the 54 cases; χ2 test result has revealed that there was no significant difference in the PONV incidence between the rhomboid and control groups.

None of the patients had block-related complications in group R.

Discussion

In the current study, ultrasound-guided RIB block significantly enhanced recovery quality of female patients after mastectomy. The difference in the global QoR-40 score and two QoR-40 dimensions (emotional status and pain) had clinical importance. In addition, postoperative morphine consumption was significantly lower in group R than control group. However, we did not detect a difference in postoperative pain scores (at any of the time-points except 12th hour), intraoperative fentanyl need and postoperative rescue analgesic requests between groups. Although there was a trend toward lower PONV in the block group, the difference in PONV between groups was not statistically significant. None of the patients experienced block-related complications in group R.

The QoR-40 was developed by Myles et al in 2000,11 and it has since become the most commonly used measure of patient-reported quality of recovery after anesthesia and surgery. A previous meta-analysis of 17 studies showed that QoR-40 is a practical and suitable objective measure for both routine clinical practice and research across a broad patient population.12 In our study, global QoR-40 score of the patients who received RIB block was significantly higher than the control group at the postoperative 24th hour. All subscales of QoR-40, except psychological support, were also higher in group R than group C. However, only the emotional status and pain subscales had clinical importance. This result is consistent with the study by Yao et al.10 The authors evaluated the effect of serratus anterior plane block (SPB) combined with general anesthesia on quality of recovery of patients following mastectomy surgery. They found that global QoR-40 score and all subscales of QoR-40, except psychological support, were higher in SPB group than the control group. Emotional status, physical comfort and pain subscales had clinical importance in that study. This result suggests that combining ultrasound-guided RIB with general anesthesia enhances recovery after mastectomy surgery. We think that the most likely reason of this result is the opioid-sparing effect of RIB block. The use of opioids is associated with several postoperative complications such as nausea-vomiting, sedation and respiratory depression, urinary retention and itching. Moreover, larger doses of opioid consumption may lead to hyperalgesia and opioid tolerance, which further complicates the postoperative pain management.13 In the study by Castro-Alves et al,14 neuraxial block and general anesthesia were compared for postoperative quality of recovery after abdominal hysterectomy. The authors reported that opioid-sparing effect of the neuraxial technique was associated with higher quality of recovery scores in the postoperative period. Similarly, RIB block provided lower opioid consumption and better QoR-40 scores after mastectomy in our study.

Regional blocks have previously been reported to attenuate pain and reduce opioid consumption following breast cancer surgery.10 15 The usage of thoracic epidural block and ultrasound-guided paravertebral block are recommended as a part of multimodal analgesia.16 17 Both procedures have technical difficulty and consequently, they have a high incidence of intervention-related complications.18 Novel ultrasound-guided interfascial plane blocks which are thought to be easier and safer than neuraxial blocks, have been used for breast cancer surgery in the last decade. Recent studies evaluated the effects of pectoral nerve blocks (PECS), SPB and erector spinae plane block (ESP) on postoperative analgesia of MRM surgery. A modified PECS block effects several nerves including lateral and medial pectoral nerves, intercostobrachial nerve, thoracic intercostal nerves and long thoracic nerves.19 Although modified PECS block was recently reported to be more effective than ESP following mastectomy surgery,20 injection points are close to the surgical field. Moreover, the approach may become difficult in fatty and large breasts. An SPB effects lateral cutaneous branches of intercostal nerves and provides analgesia over anterior chest wall.21 Ultrasound-guided ESP has a simple technique and injection sites are away from the surgical field. Similar to ESP, RIB is applied from posterior chest wall (away from the involved area). The landmarks on ultrasonographic view are easy to identify. However, there is no randomized controlled trial considering the effects of RIB in the current literature. Tulgar et al 7 performed ultrasound-guided RIB in a woman aged 82 years for postoperative analgesia of mastectomy and axillary dissection. They injected 20 mL of bupivacaine 0.25% and 10 mL of lidocaine 2% and 10 mL normal saline between the rhomboid muscle and the fifth rib. They reported that NRS score of the patient was under 3 for the first 13 hours and she did not need opioid for postoperative pain management. Pinprick test revealed sensorial block between T3 and T9 in the thoracoabdominal area and pain score of the patient was <3/10 in the axillary area. Balaban and Aydın8 performed ultrasound-guided bilevel RIB (at the T3 and T4 levels) at the end of MRM and they reported that pain score was 2–3/10 over the hemithorax while the patient felt pain in the axillary area. Similar to previous reports, we found postoperative pain scores of RIB group under 4 at all time-points with significantly reduced postoperative opioid consumption compared with control group. Ultrasound-guided RIB block could not provide complete analgesia in the axillary region in our study as previously reported.7 8 22 However, none of the patients required rescue analgesic agent.

Moreover, median NRS scores were similar between group R and group C. The most likely reason is the effective multimodal analgesia strategy performed in this study. All patients received dexketoprofen and tramadol intraoperatively and morphine PCA in the postoperative period. However, morphine consumption was significantly lower in group R, which provided the advantage of lower risks of opioid-related complications in the postoperative period.

Although no significant difference was detected between group R and group C, there was a trend toward lower PONV in the block group (7.4% in group R and 22.2% in group C). We believe that the most likely reason is the lesser cumulative-morphine consumption in group R.

Our study has some limitations as well. First, we could not evaluate the sensorial block area with pin-prick test not to flaw the double-blind nature of the study. But all block procedures were performed by the same experienced anesthesiologist (BA) under ultrasound guidance and as a group, patients who received a block required significantly lower doses of opioid in the postoperative period. Second, as the block procedures were performed under general anesthesia, we did not need to include a sham group in the study. If the patients in the block group had back pain related to injections, they would have been aware of the study groups. Consequently, there would be bias in the analysis. However, none of the patients complained about injection pain in the postoperative period. Third, although the sample size of the study was calculated to detect a significant difference in QoR-40 scores of the groups with 95% power, we could not detect a difference in NRS scores between groups. Lastly, there are other alternative approaches to regional anesthesia for this patient population, such as PECS, SBP, ESP and paravertebral block. Although some comparative studies exist in the current literature,20 23 it is still not clear which one is superior to others. Future studies are needed to compare the effects of rhomboid with other regional block techniques.

Conclusion

In patients undergoing modified radical mastectomy surgery, a rhomboid interfascial block, as a component of multimodal analgesia, led to improved quality of recovery and lower opioid use.

References

Footnotes

  • Contributors BA, MKT, AU and BU contributed to the study design. BA, MKT and AU recruited study patients after randomization. AU, MKT and ÖD collected study data. BA, MKT, AU and ÖD contributed to statistical analysis. All the authors drafted the manuscript and reviewed and approved the final manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval This study got ethical approval from the Institutional Ethical Committee of Muğla Sıtkı Koçman University Clinical Trials Ethical Committee in accordance with the principles outlined in the Declaration of Helsinki.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement Data are available on reasonable request. Data will be available (following deidentification of the participant data) on request via email to the corresponding author (email: basak_ugurlu@yahoo.com)

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