Management of postoperative pain has progressed from the sole administration of opioid medication in response to pain to the administration of a variety of medications and use of techniques to prevent acute and chronic pain. Blanco was the first to describe a novel ultrasound guided interfascial plane block, the PECS1 block.[1] PECS I Block specifically targets the medial and lateral pectoral nerves located between the pectoralis major and minor muscles. Blocking these nerves is critical because they provide significant sensory and motor innervation to the pectoral muscles, which are often manipulated or stretched during surgery.[2] Serratus Plane Block (SPB) targets the lateral cutaneous branches of the intercostal nerves (T2–T9), as well as the long thoracic and thoracodorsal nerves. It effectively numbs the anterolateral chest wall but often fails to provide sufficient coverage for the pectoral nerves. In surgeries involving axillary clearance, SPB alone is frequently insufficient because it rarely ensures a sensory block of the T1 nerve. The PECS I component helps bridge this gap by reducing muscle spasms and covering nerves involved in the deeper fascial layers of the breast and axilla.[3] The combination of both block has been shown in randomized studies to significantly reduce postoperative pain scores (NRS) for up to 24 hours.[4] Patients receiving the combined block typically require lower doses of intraoperative fentanyl and postoperative rescue morphine.[5] Aim of this study was to assess the efficacy of combination of serratus plane block(SPB) and pectoral type 1 (PECS 1) block for providing postoperative analgesia in patients undergoing breast cancer surgery

After obtaining approval from institutional ethics committee, this study was conducted at a tertiary care hospital. Breast cancer patients posted to undergo elective modified radical mastectomy surgery under general anaesthesia, were enrolled in the study. Routine preoperative assessment was performed as per the institutional protocol, for all patients during which a written informed consent was obtained. Patients were instructed on how to assess and report their quality of recovery by using QOR score, VAS score and patient satisfaction score. 60 patients were randomly allocated by opaque sealed envelope technique to either into group A or group B. Group A received combination of PECS I and SPB. Patients were shifted to the operating room and peripheral venous access using 18-gauge needle was secured. Standard monitoring devices including Non-invasive blood pressure, pulse oximetry, 5- lead electrocardiography were placed and baseline readings were noted. General anaesthesia was administered in both the group as per our institutional protocol. Block was given in group A. The patient’s position was supine with the arm abducted at 90°. After skin preparation with 2.5% chlorhexidine in alcohol, to identify the targeted planes, a high-frequency (6–11 MHz) linear array ultrasound transducer (M7 PremiumTM, Mindray) was used. For PECS I, the transducer was placed medial to the coracoid process in a parasagittal orientation. In the deltopectoral groove, the axillary vessels were identified above the second rib. The probe was further moved inferiorly and laterally until the third rib was encountered. The fascial plane between the pectoralis major and pectoralis minor was identified at the level of the third rib. A 20G echogenic needle was inserted from the cephalad end to reach the fascial plane. After negative aspiration, 10 ml of 0.25% bupivacaine was administered.[6] For SAP block transducer was placed on the midaxillary line at the nipple level. The fifth and sixth ribs were identified with the pleura sliding underneath. The serratus anterior muscle lies immediately over the ribs. The needle was inserted from the anterior aspect towards the posterior direction. After negative aspiration, 25 ml of 0.25% bupivacaine was injected deep to the serratus anterior muscle.[7] In group B, no block was given. All the vital parameters like blood pressure, oxygen saturation, heart rate were measured before and after induction and every 5 minutes intraoperatively. Fentanyl boluses were given when BP and HR increased by 15%. After the end of surgery patients were extubated and shifted to postoperative ward and VAS score were assessed. Intravenous Paracetamol 15mg/kg was given during closure of skin, then intravenous Paracetamol 15mg/kg was continued every 8 hrs for 48 hrs. When VAS>5, intravenous fentanyl 2 mcg/kg was given. Patient satisfaction scale as calculated (0 to 10, where 0 means very dissatisfied, 10 means very satisfied). Other parameters like postoperative nausea vomiting were noted. QOR-15 is a Fifteen-item questionnaire with fifteen sets of questions were asked and patient were asked to respond in “yes” or “No”. Patient satisfaction score ranges from 0 to 10, where score of 0 denotes very dissatisfied and score of 10 means very satisfied regarding the treatment patient is receiving. Time of first fentanyl request in the post-operative period and sedation by Ramsay sedation score were monitored.. Normality of distribution was ensured using the Kolmogorov–Smirnov test. For the primary outcome (QoR-15 score), we calculated the mean difference and the 95%CI. Continuous outcomes were compared using Student’s t-test, and we used the non-parametric Mann-Whitney U test if the assumptions of parametric testing were not met. Categorical data were compared using the chi-squared test. We designated a p < 0.001 as the threshold of statistical significance.

The group A and group B were similar concerning baseline demographic characteristics, ASA physical status and surgery duration. VAS score was low in group A compared to group B which was statistically significant.(table 1). Table 1: Comparison of VAS score between both groups VAS score Group A Group B p value 1 hour 2 (2, 3) 6 (5, 7) <0.001 6 hours 2 (2, 3) 4 (4, 7) <0.001 12 hours 2 (2, 3) 4 (4, 6) <0.001 24 hours 3 (2, 3) 5 (4, 6) <0.001 48 hours 4 (3, 4) 5 (4, 6) 0.231 Time of administration of first dose of fentanyl was delayed in A group in comparison to B group. (table 2) Table 2: Comparison of time of first analgesic request between both groups Variable Group A Group B p value Time of first consumption of Fentanyl (hours) 7 (5, 8) 2 (2, 4) <0.001 The total score for domains of QOR-15 was significantly higher in A group (Median = 130 (120, 140)) as compared to B group (Median = 100 (90, 120)) (p value<0.001). The individual scores of each item was also different between the groups as given in Table 3. Table 3: Comparison of QOR-15 scores between both groups Variable Group A Group B p value Pain 0 (0, 10) 10 (10, 10) <0.001 Moderate Pain 0 (0, 0) 10 (0, 10) 0.004 Severe pain 0 (0, 0) 0 (0, 0) 0.003 Physical comfort 50 (40, 50) 30 (30, 40) <0.001 Able to breathe easy 10 (10, 10) 10 (10, 10) 0.559 Been able to enjoy food 10 (10, 10) 10 (0, 10) <0.001 Feeling rested 10 (10, 10) 10 (0, 10) 0.001 Have had a good sleep 10 (10, 10) 10 (10, 10) 0.002 Nausea and vomiting 10 (0, 10) 0 (0, 10) 0.002 Physical Independence 20 (20, 20) 20 (10, 20) 0.001 Able to look after personal toilet and hygiene 10 (10, 10) 10 (10, 10) 0.155 Able to return to work or usual home activities 10 (10, 10) 10 (0, 10) 0.005 Psychological support 20 (20, 20) 20 (10, 20) <0.001 Able to communicate with family and friends 10 (10, 10) 10 (10, 10) 0.002 Getting support from hospital doctors and nurses 10 (10, 10) 10 (10, 10) 0.046 Emotions 40 (40, 40) 30 (30, 30) <0.001 Feeling comfortable and in control 10 (10, 10) 10 (0, 10) 0.002 Having a feeling of general well being 10 (10, 10) 10 (0, 10) 0.004 Feeling worried or anxious 10 (10, 10) 10 (10, 10) 0.065 Feeling sad or depressed 10 (10, 10) 10 (0, 10) 0.001 Total score 130 (120, 140) 100 (90, 120) <0.001 The median patient satisfaction score was significantly higher in A group (Median = 7 (7, 8)) as compared to B group (Median = 6 (5,6)) (p value < 0.001). It was also found that VAS pain score was significantly lesser for the A group (Median = 3 (3, 4)) as compared B group (Median = 5 (4, 6)) (p value < 0.001). But it was found that there is no significant difference in the Ramsay sedation score between the groups as given in Table 4. Table 4: Comparison of different scores between both groups Variable Group A Group B p value Patient satisfaction score 9 (8, 9) 6 (5, 6) <0.001 Ramsay sedation score 2 (2, 2) 2 (2, 2) 1.000

Our study demonstrated that combination of serratus plane block(SPB) and pectoral type 1 (PECS 1) block significantly reduces postoperative NRS pain scores up to 24 hours postoperatively compared to without block group. This block combination results in, lower postoperative rescue analgesia requirement, and higher patient satisfaction than those who received no block. The analgesic efficacy of PECS I block for breast cancer surgery is controversial. Cros et al[8] reported that PECS I did not improve postoperative analgesia after breast cancer surgery. Contrary to this, some authors demonstrate the PECS I block effectiveness with simultaneous administration with the PVB or PECS II block.[9] In their retrospective cohort study, Abdallah et al[10] reported that PECS I and SPB were similarly effective in reducing postoperative opioid consumption and postoperative nausea and vomiting after ambulatory breast cancer surgery. Hetta and Rezk[11] detected sufficient sensory blockade at T1-T7 dermatomal levels for 100 % of patients after PVB, and this rate remained at 40 % after SPB. Kunigo et al[12] performed SPB with 20 mL and 40 mL local anesthetic drugs at the 4th rib level in their study’s midaxillary line. They performed dermatomal examination with the pinprick test and found T1 involvements in 0 patients in the 20 mL group and three patients in the 40 mL group, with T2 involvement in three patients in the 20 mL group and five patients in the 40 mL group. As a result, 20 ml group patients may have required more rescue analgesia due to pain caused by axillary dissection that SPB cannot control. A few theories can explain the analgesic mechanism of PECS I block. Firstly, PECS I may reduce pectoralis major and minor muscle spasms after surgery. Secondly, the medial and lateral pectoral nerves may contain sensory innervations. Thirdly, medial and lateral pectoral nerves can merge with the intercostal nerves’ anterior cutaneous branches and have an analgesic effect. Recently, some authors have proposed combining the PECS I, PECS II, and SPB techniques under the SAP block from a single injection point around the fourth rib. They have explained in detail that the upper intercostal nerves’ branches provide the anterolateral chest wall’s sensory innervation without any contribution from the brachial plexus.[13] Contrary to this, in the study by Sopena-Zubiria et al[14] it was concluded that the addition of the pectoral nerve block to the thoracic paravertebral block in reconstructive breast surgery improves the results obtained, provides better analgesia in the early postoperative period and lower sedation requirement. Yesiltas S et al[15] in their study concluded that concurrent application of ultrasound-guided pectoral type 1 (PECS I) and serratus plane block (SPB) can provide more effective and reliable perioperative analgesia in patients undergoing breast cancer surgery which is in agreement with our study.

We conclude that combination of serratus plane block (SPB) and pectoral type 1 (PECS 1) block can provide more effective and reliable postoperative analgesia and increase patient satisfaction in breast cancer surgery.

1. Blanco R. The 'pecs block': a novel technique for providing analgesia after breast surgery. Anaesthesia. 2011;66:847-848. 2. Blanco R, Fajardo M, Parras Maldonado T. Ultrasound description of Pecs II (modified Pecs I): a novel approach to breast surgery. Rev Esp Anestesiol Reanim. 2012;59:470-475. 3. Goswami S, Kundra P, Bhattacharyya J. Pectoral nerve block1 versus modified pectoral nerve block2 for postoperative pain relief in patients undergoing modified radical mastectomy: a randomized clinical trial. Br J Anaesth. 2017;119:830-835. 4. Blanco R, Parras T, McDonnell JG, Prats-Galino A. Serratus plane block: a novel ultrasound-guided thoracic wall nerve block. Anaesthesia. 2013;68:1107-1113. 5. Pérez MF, Miguel JG, de la Torre PA. A new approach to pectoralis block. Anaesthesia. 2013;68:430. 6. Wang W, Song W, Yang C, Sun Q, Chen H, Zhang L, et al. Ultrasound-Guided Pectoral Nerve Block I and Serratus-Intercostal Plane Block Alleviate Postoperative Pain in Patients Undergoing Modified Radical Mastectomy. Pain Physician. 2019;22:E315-E323. 7. Najeeb HN, Mehdi SR, Siddiqui AM, Batool SK. Pectoral Nerves I, II and Serratus Plane Blocks in Multimodal Analgesia for Mastectomy: A Randomised Clinical Trial. J Coll Physicians Surg Pak. 2019;29:910-914. 8. Cros J, Sengès P, Kaprelian S, Desroches J, Gagnon C, Labrunie A, et al. Pectoral I Block Does Not Improve Postoperative Analgesia After Breast Cancer Surgery: A Randomized, Double-Blind, Dual-Centered Controlled Trial. Reg Anesth Pain Med. 2018;43:596-604. 9. Ueshima H, Otake H. Addition of transversus thoracic muscle plane block to pectoral nerves block provides more effective perioperative pain relief than pectoral nerves block alone for breast cancer surgery. Br J Anaesth. 2017;118:439-443. 10. Abdallah FW, MacLean D, Madjdpour C, Cil T, Bhatia A, Brull R. Pectoralis and Serratus Fascial Plane Blocks Each Provide Early Analgesic Benefits Following Ambulatory Breast Cancer Surgery: A Retrospective Propensity-Matched Cohort Study. Anesth Analg. 2017;125:294-302. 11. Hetta DF, Rezk KM. Pectoralis-serratus interfascial plane block vs thoracic paravertebral block for unilateral radical mastectomy with axillary evacuation. J Clin Anesth. 2016;34:91-97. 12. Kunigo T, Murouchi T, Yamamoto S, Yamakage M. Injection Volume and Anesthetic Effect in Serratus Plane Block. Reg Anesth Pain Med. 2017;42:737-740. 13. Govshievich A, Kirkham K, Brull R, Brown MH. Novel approach to intractable pectoralis major muscles spasm following sub-muscular expander-implant breast reconstruction. Plast Surg Case Studies. 2015;1:68-70. 14. Sopena-Zubiria LA, Fernández-Meré LA, Valdés Arias C, Muñoz González F, Sánchez Asheras J, Ibáñez Ernández C. Thoracic paravertebral block compared to thoracic paravertebral block plus pectoral nerve block in reconstructive breast surgery.Rev Esp Anestesiol Reanim. 2012;59:12-17 15. Yesiltas S, Türköz A, Çalım M, Yılmaz S, Esen A, Daşkaya H, Karaaslan K. Comparison of serratus plane block alone and in combination with pectoral type 1 block for breast cancer surgery: a randomized controlled study. Hippokratia. 2021 Jan-Mar;25(1):8-14