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Indian Journal of Surgical Oncology logoLink to Indian Journal of Surgical Oncology
. 2021 Jan 4;12(1):158–163. doi: 10.1007/s13193-020-01269-2

Randomized controlled trial comparing the efficacy of pectoral nerve block with general anesthesia alone in patients undergoing unilateral mastectomy

Sudivya Sharma 1,✉, Shashank Tiwari 2, Kailash Sharma 1, Nita Nair 3
PMCID: PMC7960852  PMID: 33814847

Abstract

This study was conducted to evaluate the efficacy of pectoral nerve block for post-operative analgesia in breast surgery patients. This double blinded, randomized controlled trial was conducted after Clinical Trials Registry-India registration. Sixty ASA grade I–II female patients undergoing unilateral modified radical mastectomy under general anesthesia, were recruited pre-operatively in two groups. PECS group (n  =  29) was given ipsilateral pectoral nerve block I & II while the CONTROL group (n  =  29) directly proceeded to surgery. Our primary outcome was comparison of immediate post-operative pain scores at rest and movement. The secondary outcomes were post-operative pain scores at 2, 4, 6, 12, 18, and 24 h, total intraoperative fentanyl consumption, time to rescue analgesia, post-operative nausea vomiting, and complications, if any. Categorical data was analyzed by using the chi-squared test or Fishers Exact test. Comparison of pain scores was analyzed by using the Independent sample t test. The immediate post-operative pain scores in two groups were comparable. The pain scores were also comparable at 4, 6, 12, and 24 h; but statistically significantly lower in PECS group at 2 and 18 h. The total intraoperative fentanyl consumption was also reduced in PECS group (P = 0.009). Only 9 patients in PECS group (796.5 min) as compared to 22 patients in CONTROL group (387.7 min) required rescue analgesia (P  =  0.001). Pectoral nerve block benefits patients undergoing mastectomy by achieving similar post-operative pain scores with decreased consumption of intraoperative and post-operative opioids. Registration. Clinical Trials Registry of India, (CTRI/2017/04/008289). ctri.nic.in

Keywords: Pectoral nerve block, General anesthesia, Analgesia, Post-operative pain, Mastectomy

Introduction

Breast cancer has become the most common cancer in India and worldwide. It accounts for 27% of cancer in women as per the National Cancer Registry [1]. Breast surgery remains the most effective therapeutic intervention. Breast surgeries, especially mastectomies with axillary clearance, are associated with moderate to severe post-operative pain and subsequently, chronic pain or persistent pain [2]. Poorly managed pain affects recovery, length of hospital stay, patient satisfaction, and quality of life and poses a risk of developing chronic pain [3]. It has been studied in experimental cancer models that the modalities used to alleviate pain may have a role in decreasing the risk of tumor recurrence or metastasis. Moreover, persistence of pain itself can lead to tumor progression due to its immunosuppressive action [4, 5].

Multimodal analgesia approach for management of post mastectomy pain consists of drugs like acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDS), antiepileptic drugs, systemic opioids, and regional anesthesia. Regional anesthesia techniques include thoracic epidural analgesia, thoracic spinal, paravertebral block, intercostal nerve block, wound infiltration, and recently introduced pectoral nerve block (Pecs block). Furthermore, recent evidence suggests that local anesthetic agents have protective antiproliferative effect and can prevent cancer cell migration [6].

Pectoral nerve block is being studied worldwide with suggestions of better pain control and reduction in opioid consumption, along with few studies showing comparable results [7]. Regional blocks have potential risks and are time consuming and need robust evidence of benefit to be incorporated into practice. We proposed a study to evaluate the efficacy of Pectoral Nerve Block for breast surgery patients in terms of pain management and peri-operative opioid requirements.

The primary outcome of the study was reduction in immediate post-operative pain scores at rest and movement as soon as the patient is received in Post anesthesia care unit (PACU); this was considered as time zero (0 h). The secondary outcomes included post-operative pain score at 2, 4, 6, 12, 18, 24 h or at discharge whichever was earlier; time to request rescue analgesia, i.e., inj. tramadol, total intraoperative fentanyl consumption, frequency of post-operative nausea vomiting and to note the complications, if any.

Methods

This prospective double blinded, randomized, clinical trial was conducted after obtaining approval from the Institutional Ethical Committee at Tata Memorial Center, Mumbai (Reg. No. 1810) dated 01/02/2017, and was prospectively registered with Clinical Trials Registry of India (CTRI/2017/04/008289). The allotted period of study was 1 year, but the recruitment was completed within 9 months, i.e., from May 2017 to January 2018. Sixty ASA grade I–II female patients in the age group of 18–80 years, undergoing unilateral modified radical mastectomy under general anaesthesia, were recruited for the study after obtaining written informed consent for participation in this study (in addition to anesthesia consent), followed by randomization. Randomization to one of the two groups was done pre-operatively through a computer generated sequence. The allocation concealment was done by opaque envelope technique. The patient and the assessor, i.e., acute pain service (APS) team were unaware of the group allocation.

Numeric rating scale (NRS) for assessment of pain was explained to patients pre-operatively. According to this scale, patient was required to rate their pain intensity by circling a number that best describes it, on a defined scale of 0–10; with zero indicating no pain and 10 indicating worst pain imaginable. The patients with sensitivity to local anesthetic, bleeding disorders or those receiving anticoagulant, body mass index (BMI) >  35/kg/m2, chest wall deformity, pregnancy, post radiotherapy, patients on other studies which can interfere with the outcome of study, and patients with deranged liver or renal function tests were excluded from the study. Patients in both the groups were given general anesthesia. In the operation theatre, standard monitors were attached. Peripheral intravenous access was secured by 22G cannula. After pre-oxygenation with 100% oxygen, anesthetic induction was done using inj. fentanyl 2 mcg/kg and inj. propofol 2 mg/kg, and after assessing adequate mask ventilation, non-depolarizing neuromuscular blocking agent was administered. The airway was secured by using second-generation laryngeal mask airway of appropriate size and anesthesia was maintained using O2 + Air + isoflurane. After completion of surgery, neuromuscular block was reversed with inj. Neostigmine 0.05 mg/kg and inj. Glycopyrrollate 8 mcg/kg. Once it was ensured that the patient is breathing adequately, conscious and following commands, laryngeal mask was removed and patient was shifted to Post Anesthesia Care Unit (PACU).

Group PECS (n  =  30 patients) was given ipsilateral Pectoral nerve block I & II under ultrasonographic guidance by experienced an esthesiologist [8] (i.e., consultant or senior resident who were trained in pectoral nerve block; or junior resident who had performed at least five such blocks under the guidance of senior anesthesiologist) post induction, while the group CONTROL (n  =  30 patients) directly proceeded to surgery.

To perform pectoral nerve block, the patient was positioned supine with the ipsilateral arm abducted and externally rotated. The block was performed under sonography guidance using machine Sonocite Edge II with 6–13 Hz frequency transducer linear probe. Taking complete aseptic precautions, after cleaning and draping the infraclavicular and axillary area, probe was placed at infraclavicular region and moved laterally to locate the axillary artery and vein directly above the 2nd rib, along with identification of pectoralis major and pectoralis minor muscles. The point of skin puncture was infiltrated with 2 ml of 2% lignocaine, 23 G spinal needle was then inserted in plane with ultrasound (USG) probe into the fascial plane and 10 ml of inj. bupivacaine 0.25% was injected between the pectoral muscles. Then, the USG probe was moved towards the axilla till serratus anterior muscle was identified above 3rd and 4th ribs; thereafter, the needle was reinserted into the fascial plane between pectoralis minor muscle and serratus anterior muscle, and 20 ml of inj. bupivacaine 0.25% was deposited.

Both the groups received inj. fentanyl 25 mcg, if there were intraoperative rise in heart rate and/or blood pressure by 20% above preoperative baseline. All patients were given inj. paracetamol 15 mg/kg and inj. ondansetron 4 mg at the time of wound closure.

In the ward, both sets of patients received paracetamol 15 mg/kg 8 hourly (not exceeding 3 g/day) and inj. tramadol 50 mg IV as a rescue analgesic, i.e., on patient’s demand or if pain score was 4 or more (not exceeding 3 times per day) for first 24 h or discharge, whichever was earlier.

Assessment of pain scores in recovery room (PACU) was done by recovery room anesthesiologist and in wards by the APS team using the NRS. They were unaware of the group allocation.

Sample size calculation was based on an observational pilot study of 24 routine mastectomy patients at our center (similar to CONTROL group in our study), who were administered general anesthesia and post-operative analgesia as per the institutional protocol and immediate post-operative pain scores (mean) were assessed at rest and on movement soon after the patient was shifted to the PACU. These scores were considered as reference scores (At rest − 3.7, On movement – 6.5).

The proposed objective was to obtain 30% reduction of the baseline post-operative pain score at rest and at movement by giving pectoral nerve block. The sample required for the same for 80% power required recruitment of 25 patients in each group and hence, we aimed at recruiting 30 patients each, to account for attrition.

Statistical analysis was performed using IBM SPSS Statistics version 21 (SPSS Inc., Chicago, Illinois, USA). Demographical data and scales computed for each domain score were presented as mean (Standard Deviation), median, range, and percentage. Categorical data was analyzed by using the chi-squared test or Fishers Exact test (for binary data). Comparison of pain scores for the first 24 h (0, 2, 4, 6, 12, 18, and 24 h) of the two groups was analyzed using the Independent sample t test or Mann–Whitney U test as per the distribution of data. Log rank test was used for estimation of comparison of time to first rescue analgesia. P value <  0.05 was considered to be statistically significant.

Results

A total of seventy four patients were screened, out of which 60 patients were randomized into two groups, PECS group and CONTROL group (Fig. 1). The two groups were comparable with respect to demographic profile, i.e.. age, weight, height, body mass index, chemotherapy status, type of surgery, and ASA physical status (Table 1). The post-operative pain scores in the two groups were comparable at immediate post-operative period, along with other time points, i.e., 4, 6, 12, 24 h post-operatively, and statistically significantly lower in PECS group at 2 h (p  =  0.052 rest, p  =  0.011 movement) and 18 h ([p  =  0.039] rest, [p  =  0.030] movement) (Figs. 2 and 3).

Fig. 1.

Fig. 1

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Consort diagram- patient enrolment and randomization

Table 1.

Table showing distribution of patient’s characteristics in PECS and CONTROL group

Variable Pecs group (n = 29) Control group (n = 29) P Value (significant if ≤ 0.05)
Age in years (mean ± SD) 47.48 ± 10.76 50.38 ± 10.40 0.303
Weight in Kg (mean ± SD) 60.48 ± 10.63 61.36 ± 9.82 0.749
Height in Cm (mean ± SD) 154.52 ± 8.50 153.71 ± 5.05 0.67
BMI (mean ± SD) 25.38 ± 3.87 25.78 ± 4.38 0.72
ASA grade I/II (%age) 65.5/34.5 62.1/37.9 0.785
Chemotheraphy (%age) 16 (55.2%) 21 (72.4%) 0.17
Type of surgery (%age) MRM 15 (51.7%) 11(37.9%) 0.429
SMAC 14 (48.3%) 18(62.1%)
Duration of surgery in minutes 118.45 (26.12) 120.17 (19.61) 0.77
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Fig. 2.

Fig. 2

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Line diagram showing distribution of mean pain scores at rest in PECS and CONTROL group at various time points

Fig. 3.

Fig. 3

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Line diagram showing distribution of mean pain scores at movement in PECS and CONTROL group at various time points

In PECS group, out of 29 patients, only 8 patients required single dose of post-operative rescue analgesia and 1 patient required two doses of rescue analgesic. In CONTROL group, 18 patients required single dose of rescue analgesia and 4 patients required two doses of rescue analgesic. The mean time when patient first requested rescue analgesia was 796.5 (confidence interval 634.310–958.793) and 387.7 (confidence interval 231.396–544.121) minutes for PECS and CONTROL groups respectively. This was statistically significantly delayed in PECS group (p  <  0.001) (Fig. 4).

Fig. 4.

Fig. 4

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Graph showing cumulative probability of receiving rescue analgesia in PECS and CONTROL group (Kaplan Mier- one minus cumulative survival curve)

All the patients received 2 µg per kg of fentanyl at the time of induction. The intraoperative maintenance fentanyl requirement was less in PECS group and it was statistically significant (Fig. 5). In PECS group, it was 46.52 (± 18.05) micrograms while in CONTROL, group it was 68.20 (±  28.13) micrograms [P  = 0.003]. The total intraoperative fentanyl required in PECS group was 136.90 (± 24.97) micrograms while in CONTROL group it was 158.79 (±  35.372) micrograms [P  =  0.009].

Fig. 5.

Fig. 5

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Diagram showing total intraoperative fentanyl requirement in PECS (red) and CONTROL (blue) group

Only three patients had post-operative nausea and all were in CONTROL group. The frequency of PONV in both groups was comparable and lower than expected. No complications were encountered in any of the patients in any group.

Discussion

In this study, we found comparable immediate post-operative pain scores in CONTROL and PECS group. Secondarily, there was significant delay in time to request tramadol in post-operative period in PECS group. Pain is an important primary outcome, as well as a standardized endpoint in perioperative medicine initiative with relation to patient comfort, satisfaction, and hospital stay [9]. But it has its limitations, like in our study, we ensured adequate intraoperative analgesia using objective criteria of giving supplementary fentanyl doses for every hemodynamic response to surgical stimuli; this maybe the reason of achieving lower immediate post-operative pain scores in comparison to our pilot study, and also comparable pain scores in the two trial arms.

The time to first request of rescue analgesic was significantly delayed in PECS group. Only 31% of patients in PECS group required rescue analgesia in first 24 h, in contrast to near 76% in the CONTROL group.

In a recent meta-analysis, all randomized controlled trials [10–17] published till date, were included comparing pectoral nerve block with general anesthesia alone. They concluded that Pecs block is superior to control in terms of clinically important reductions in (area under the curve of) rest pain scores during 24 h postoperatively and 24 h morphine consumption (at least 30.0 mg), by a weighted mean difference [95% CI] of  −  30.5 mg [−  42.2,  −  18.8] (P < 0.00001). They recommended incorporating Pectoralis-II block into multimodal analgesia [7].

Our pain scores were comparable in both groups in immediate postoperative period which was in contrast with three initial landmark studies [10–12] while two trials had similar findings of comparable pain scores in their study [13, 18].

In our study, time to first request of analgesic dose was significantly delayed in PECs group, which is in coherence with another study [14]. Many authors have compared post-operative opioid consumption by using morphine/fentanyl patient controlled analgesia, and they have found statistically significant reduction in opioid consumption with Pecs block [14, 15, 19, 20].

Three recent trials reported low opioid (Fentanyl/ Morphine) consumption in pecs group, and our study is consistent with these findings since the total intraoperative fentanyl consumption was lower in PECS group than CONTROL group [p  =  0.009] [14, 15, 21].

The existing incidence of PONV in operated cases of breast cancer is 24% [22]. We did not find any significant difference in frequency of PONV in both groups. Also, very few of our patients experienced PONV. The possible reasons for the same could be better pain management, use of air with inhalational agent intraoperatively, prophylactic antiemetic administration and mandatory use of antiemetic with every dose of tramadol. No complication of Pecs block was reported in any patient. Literature suggests that there are chances of potential complications like intravascular injection in acromiothoracic artery, pneumothorax, intraneural injection, and local anesthetic systemic toxicity. Furthermore, we did encounter occasional incidence of electrocautery malfunction because of local anesthetic injection, as reported by one case study [23].

This study was randomized, double blinded and suggests that this block may not result in superior pain relief, but trends towards decreasing perioperative opioid consumption. The comparable duration of surgery in both the groups suggests that it is less time consuming. It has given us a valuable option for high-risk cases where regional techniques are preferred over conventional general anaesthetic drugs because of their opioid sparing and anesthetic drug sparing action. The block was given after induction of anesthesia keeping patient comfort in mind, but before the surgery, as pre-emptive analgesia.

Our study has few limitations. In our study, no placebo was used. The block was given after induction for patient comfort, but this led to decreased contact time for the drug. Also, under anesthesia the sensory level of the block could not be assessed. The use of patient controlled analgesia pumps is a better way to gauge consumption, but as this was not the standard of care in our institute, it was not used. Further, following up patients for a longer duration would have provided insight regarding long-term effect of Pecs block on chronic pain (risk is 29%).

Conclusion

Pecs block provides comparable analgesia to general anesthesia alone; with decreased need for rescue opioids postoperatively as well as decreased consumption of intraoperative fentanyl. Further studies with larger sample size and longer follow-up are required to ascertain its clinical utility firmly.

Acknowledgements

I would like to thank Dr. J.V. Divatia, our Head of Department and Dr. Sumitra Bakshi for their kind efforts and support. I am grateful to Dr. Manoj Gorade for statistical analysis and Dr. Anjana Srivastava for trial coordination.

Authors’ Contributions

Sudivya Sharma: Concept, design, definition of intellectual content, literature search, experimental study, data analysis, statistical analysis, manuscript preparation, manuscript editing and manuscript review.

Shashank Tiwari: Concept, design, definition of intellectual content, literature search, experimental study, data acquisition, data analysis, statistical analysis, manuscript preparation, manuscript editing.

Kailash S Sharma: Concept, design, definition of intellectual content, literature search, experimental study, manuscript preparation, manuscript editing and manuscript review.

Nita Niar: Concept, design, definition of intellectual content, literature search, experimental study, manuscript editing and manuscript review.

Funding

The funding of this study is in the form of grants- Intramural Grant, Tata Memorial Hospital.

Compliance with Ethical Standards

Conflicts of interest

The authors declare that they have no conflict of interest.

Footnotes

Presentation: Paper presentation in ISACON 2019, held in Bangalore in the month of November.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Contributor Information

Sudivya Sharma, Email: drsudivyasharma@gmail.com.

Shashank Tiwari, Email: shashank30.2009@gmail.com.

Kailash Sharma, Email: rashmikailashsharma@yahoo.co.in.

Nita Nair, Email: nitanair@hotmail.com.

References

  • 1.Population Based Cancer Registry. National Cancer Registry Programme (NCRP), Indian Council of Medical Research (ICMR). Available from: http://www.ncrpindia.org/
  • 2.Fecho K, Miller NR, Merritt SA, Klauber-Demore N, Hultman CS, Blau WS. Acute and persistent postoperative pain after breast surgery. Pain Med. 2009;10(4):708–715. doi: 10.1111/j.1526-4637.2009.00611.x. [DOI] [PubMed] [Google Scholar]
  • 3.Kehlet H, Holte K. Effect of postoperative analgesia on surgical outcome. Br J Anaesth. 2001;87:62–72. doi: 10.1093/bja/87.1.62. [DOI] [PubMed] [Google Scholar]
  • 4.Hooijmans CR, Geessink FJ, Ritskes-Hoitinga M, Scheffer GJ. A systematic review and meta-analysis of the ability of analgesic drugs to reduce metastasis in experimental cancer models. Pain. 2015;156(10):1835–1844. doi: 10.1097/j.pain.0000000000000296. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 5.Sekandarzad MW, van Zundert AAJ, Lirk PB, Doornebal CW, Hollmann MW. Perioperative Anesthesia Care and Tumor Progression. AnesthAnalg. 2017;124(5):1697–1708. doi: 10.1213/ANE.0000000000001652. [DOI] [PubMed] [Google Scholar]
  • 6.Heaney A, Buggy DJ. Can anaesthetic and analgesic techniques affect cancer recurrence or metastasis? Br J Anaesth. 2012;109:17–28. doi: 10.1093/bja/aes421. [DOI] [PubMed] [Google Scholar]
  • 7.Hussain N, Brull R, McCartney CJL, et al. Pectoralis-II myofascial block and analgesia in breast cancer surgery: a systematic review and meta-analysis. Anesthesiology. 2019;131(3):630–648. doi: 10.1097/ALN.0000000000002822. [DOI] [PubMed] [Google Scholar]
  • 8.Kim SC, Hauser S, Staniek A, Weber S. Learning curve of medical students in ultrasound guided simulated nerve block. J Anesth. 2014;28(1):76–80. doi: 10.1007/s00540-013-1680-y. [DOI] [PubMed] [Google Scholar]
  • 9.Myles PS, Boney O, Botti M, et al. Systematic review and consensus definitions for the Standardised Endpoints in Perioperative Medicine (StEP) initiative: patient comfort. Br J Anaesth. 2018;120(4):705–711. doi: 10.1016/j.bja.2017.12.037. [DOI] [PubMed] [Google Scholar]
  • 10.Kumar S, Goel D, Sharma SK, et al. A randomised controlled study of the post-operative analgesic efficacy of ultrasound-guided pectoral nerve block in the first 24 h after modified radical mastectomy. Indian J Anaesth. 2018;62(6):436–442. doi: 10.4103/ija.IJA_523_17. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 11.Kim DH, Kim S, Kim CS, et al. Efficacy of pectoral nerve block type II for breast-conserving surgery and sentinel lymph node biopsy: a prospective randomized controlled study. Pain Res Manag. 2018;2018:4315931. doi: 10.1155/2018/4315931. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 12.Abdelaziz Ahmed AA. Efficacy of pectoral nerve block using bupivacaine with or without magnesium sulfate. Anesth Essays Res. 2018;12(2):440–445. doi: 10.4103/aer.AER_37_18. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Versyck B, van Geffen GJ, Van Houwe P. Prospective double blind randomized placebo-controlled clinical trial of the pectoral nerves (Pecs) block type II. J ClinAnesth. 2017;40:46–50. doi: 10.1016/j.jclinane.2017.03.054. [DOI] [PubMed] [Google Scholar]
  • 14.Hassn AM, Zanfaly HE, Biomy TA. Pre-emptive analgesia of ultrasound-guided pectoral nerve block II with dexmedetomidine-bupivacaine for controlling chronic pain after modified radical mastectomy. Res OpinAnesth Intensive Care. 2016;31:6–13. doi: 10.4103/2356-9115.184078. [DOI] [Google Scholar]
  • 15.Bashandy GM, Abbas DN. Pectoral nerves I and II blocks in multimodal analgesia for breast cancer surgery: a randomized clinical trial. RegAnesth Pain Med. 2015;40:68–74. doi: 10.1097/AAP.0000000000000163. [DOI] [PubMed] [Google Scholar]
  • 16.Neethu M, Pandey RK, Sharma A, et al. Pectoral nerve blocks to improve analgesia after breast cancer surgery: a prospective, randomized and controlled trial. J ClinAnesth. 2018;45:12–17. doi: 10.1016/j.jclinane.2017.11.027. [DOI] [PubMed] [Google Scholar]
  • 17.Kanitkar R, Mane A, Agashe A, Kulkarni M, Deshmukh S. Abstract P2-12–13: Modified pectoral nerves block for postoperative analgesia after modified radical mastectomy: a comparative study. Cancer Res. 2016;76:P2-12–13. [Google Scholar]
  • 18.Cros J, Sengès P, Kaprelian S, et al. Pectoral I block does not improve postoperative analgesia after breast cancer surgery: a randomized, double-blind, dual-centered controlled trial. RegAnesth Pain Med. 2018;43(6):596–604. doi: 10.1097/AAP.0000000000000779. [DOI] [PubMed] [Google Scholar]
  • 19.ELdeen HM. Ultrasound guided pectoral nerve blockade versus thoracic spinal blockade for conservative breast surgery in cancer breast: a randomized controlled trial. Egypt J Anaesth. 2016;32:29–35. doi: 10.1016/j.egja.2015.08.005. [DOI] [Google Scholar]
  • 20.Wahba SS, Kamal SM. Thoracic paravertebral block versus pectoral nerve block for analgesia after breast surgery. Egypt J Anaesth. 2014;30:129–135. doi: 10.1016/j.egja.2013.10.006. [DOI] [Google Scholar]
  • 21.Morioka H, Kamiya Y, Yoshida T, Baba H. Pectoral nerve block combined with general anesthesia for breast cancer surgery: a retrospective comparison. JA Clinical Reports. 2015;1:15–18. doi: 10.1186/s40981-015-0018-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 22.Morino R, Ozaki M, Nagata O, Yokota M. Incidence of and risk factors for postoperative nausea and vomiting at a Japanese Cancer Center: first large-scale study in Japan. J Anesth. 2013;27:18–24. doi: 10.1007/s00540-012-1468-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 23.Bakshi SG, Karan N, Parmar V. Pectoralis block for breast surgery: a surgical concern? Indian J Anaesth. 2017;61:851–852. doi: 10.4103/ija.IJA_455_17. [DOI] [PMC free article] [PubMed] [Google Scholar]

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