Application Of Serratus Anterior Plane Block Combined With Parasternal Intercostal Block In Modified Radical Mastectomy

Objective:Modified radical mastectomy is the most commonly used treatment for breast cancer and is expected to be more effective.However,the surgery is more invasive and involves a wide range of nerves,resulting in more severe postoperative pain,which may even develop into chronic pain,forming Post-mastectomy Pain Syndrome（PMPS）,affecting the quality of patients’survival after surgery.Ultrasound-guided Serratus Anterior Plane Block（SAPB）has been widely used in modified radical breast cancer surgery because of its low puncture difficulty and precise analgesic effect.However,SAPB cannot effectively block the anterior cutaneous branch of the intercostal nerve,and the Parasternal Intercostal Block（PSIB）can compensate for its shortcomings.In this study,we investigated the effectiveness of SAPB combined with PSIB in modified radical surgery for breast cancer and further optimized the perioperative analgesia protocol.Methods:The study was approved by the hospital’s medical ethics committee,and patients or their families signed an informed consent form before surgery.One hundred female patients,aged 30-80 years,who underwent elective unilateral radical breast cancer modified radical surgery from January 2021 to December 2021 in our hospital were selected.According to the random number table method,the study population was divided into two groups:group G（general anaesthesia group,n=50）and group SP（anterior serratus plane combined with parasternal intercostal nerve block compound general anaesthesia group,n=50）.Patients in both groups were given the same protocol for induction and maintenance of anaesthesia.Anesthesia induction:patients in both groups were given intravenous Penehyclidine Hydrochloride（PCHE）0.3 mg,midazolam0.04 mg/kg,propofol 2.5 mg/kg,sufentanil 0.5μg/kg and rocuronium 0.6mg/kg;anesthesia maintenance:intravenous pumped remifentanil 0～0.3μg/kg/min and inhaled sevoflurane 1±0.1MAC was used to maintain the depth of anesthesia BIS between40～60.After induction of general anaesthesia,in the SP group,an anterior serratus plane block was performed at the level of the fourth rib in the mid-axillary line of the chest wall on the affected side,using an ultrasound-guided in-plane technique,and 25 ml of local anaesthetic 0.375%ropivacaine was injected;in the parasternal area between the fourth and fifth ribs,a parasternal intercostal nerve block was performed and 15 ml of local anaesthetic 0.375%ropivacaine was injected.The mean arterial pressure（MAP）and heart rate（HR）were recorded at the time of admission（T₀）,immediately after the start of surgery（T₁）,10 min after the start of surgery（T₂）,at the end of surgery（T₃）and 10 min after the end of surgery（T₄）;the total intraoperative dose of remifentanil and the patient’s awakening time were recorded;the visual analogue scale（VAS）and the bruggrmann comfort scale（BCS）were recorded at 2 h（T₅）,6 h（T₆）,12 h（T₇）and 24 h（T₈）after surgery.The incidence of postoperative nausea,vomiting and adverse effects associated with nerve block were recorded;the incidence of PMPS was followed up at 6 months after surgery.Results:A total of 97 patients were completed and included in the analysis of this study,of which 1 case was lost in the G group and 2 cases were lost in the SP group,for a final count of 97 cases.There were 49 cases in group G and 48 cases in group SP.（1）There was no statistical difference between the two groups in terms of age,body mass index,ASA classification and time to surgery（P>0.05）.（2）Compared with group G,the magnitude of change in MAP and HR at T₁,T₂,T₃and T₄was smaller in patients in group SP（P<0.05）.（3）Intraoperative remifentanil dosage was significantly less in the SP group compared with the G group（P<0.05）,and there was no statistical difference in the awakening time between the two groups（P>0.05）.（4）At the moments of T₅,T₆,T₇and T₈,the VAS scores of patients in the SP group were significantly lower than those in the G group（P<0.05）,and the BCS scores were significantly higher than those in the G group（P<0.05）.（5）There was no statistical difference in the incidence of adverse reactions such as nausea and vomiting between the two groups（P>0.05）,and no puncture complications such as pneumothorax,haematoma or nerve injury occurred in either group.（6）At the 6-month postoperative follow-up,the incidence of PMPS was lower in the SP group compared with the G group,and the difference was statistically significant（P<0.05）.Conclusion:The anterior serratus plane combined with parasternal intercostal nerve block composite general anaesthesia can be safely used in modified radical mastectomy for breast cancer,significantly reducing the amount of remifentanil drug,maintaining haemodynamic stability,effectively reducing postoperative pain,improving patient comfort and reducing the incidence of PMPS.