|Year : 2022 | Volume
| Issue : 1 | Page : 37-42
A comparative study of ultrasound-guided serratus anterior plane block with pectoral nerve block type II in breast surgeries
Syed Hussain Amir, Kulsum Sheikh, Qazi Ehsan Ali, Obaid Ahmed Siddiqui, SM Arman
Department of Anesthesiology, Jawaharlal Nehru Medical College, A.M.U, Aligarh, Uttar Pradesh, India
|Date of Submission||13-Aug-2021|
|Date of Decision||18-Oct-2021|
|Date of Acceptance||25-Nov-2021|
|Date of Web Publication||25-Apr-2022|
Dr. Syed Hussain Amir
Department of Anaesthesiology, Jawaharlal Nehru Medical College, A.M.U, Aligarh, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
Background: The use of ultrasonography (USG) to identify fascial layers has led to the development of several newer interfascial techniques for analgesia of the chest and abdominal wall. Two such modalities are the Pectoral nerve block (PEC) and Serratus Anterior Plane (SAP) block. Objective: To compare the duration and quality of analgesia provided by ultrasound-guided SAP block with PEC block II in patients undergoing breast surgeries after induction of general anesthesia. Design: Randomized, double-blinded, prospective study. Methods: Sixty female patients were divided into two groups of 30 each. Patients in Group P received USG guided PEC II block, whereas patients in Group S received USG-guided SAP block after induction. Outcome Measure: The primary objective was to compare the duration of pain relief, whereas the secondary objectives were to compare the degree of pain relief, postoperative analgesic requirement within 24 h after the completion of the surgery, patient satisfaction score and complications if any. Results: The mean time of the first dose of analgesic given was 826 ± 405.24 min. in Group P and 1280 ± 264.29 min. in Group S (P < 0.001). The mean numeric rating scale score at rest at 6 h, on movement at 2 h and 6 h and satisfaction scores in Group P were significantly more than Group S. Conclusion: Ultrasound-guided SAP block provides better postoperative analgesia both in quality and duration over PEC II block.
Keywords: Diclofenac, nerve block, pectoral nerves, postoperative pain, ultrasound
|How to cite this article:|
Amir SH, Sheikh K, Ali QE, Siddiqui OA, Arman S M. A comparative study of ultrasound-guided serratus anterior plane block with pectoral nerve block type II in breast surgeries. Indian J Pain 2022;36:37-42
|How to cite this URL:|
Amir SH, Sheikh K, Ali QE, Siddiqui OA, Arman S M. A comparative study of ultrasound-guided serratus anterior plane block with pectoral nerve block type II in breast surgeries. Indian J Pain [serial online] 2022 [cited 2022 Jul 1];36:37-42. Available from: https://www.indianjpain.org/text.asp?2022/36/1/37/343830
| Introduction|| |
Postoperative pain is very common and is necessary to be managed in perioperative anaesthetic care. It is one of the main concerns for anesthesiologists and surgeons. Prolonged recovery time and length of hospital stay are the adverse clinical implications of pain on postoperative recovery. Moreover, the use of opioids for postoperative analgesia results in adverse effects, such as sedation, postoperative nausea and vomiting (PONV), urinary retention, ileus and respiratory depression leading to delayed hospital discharge. NonSteroidal Anti Inflammatory drugs usage is associated with renal function derangement and haemorrhagic disorders. Thus, multimodal analgesia, by using more than one analgesic modality to achieve effective pain control while reducing opioid-related side effects, has become the cornerstone of enhanced recovery., Modified radical mastectomy (MRM), usually performed for the treatment of breast cancer is associated with considerable acute postoperative pain and restricted shoulder mobility. There is a progression of acute to chronic pain caused by surgeries of breast and axilla in 25%–60% of cases.
The use of ultrasonography (USG) to identify fascial layers has led to the development of several newer interfascial techniques for analgesia of the chest and abdominal wall. Two such modalities are PEC block and serratus anterior plane (SAP) block. PEC I block provides blockade of medial and lateral pectoral nerves. PEC II is an extension of PEC I which blocks lateral branches of T2-T4 spinal nerves. SAP block provides blockade of lateral branches of intercostal nerves from T2-L2 spinal nerves. We hypothesised that SAP block provides better postsurgical analgesia and for a longer duration with less requirement of analgesic than PEC II block in breast surgeries as SAP block targets the thoracic nerves more selectively than PEC blocks. Since there is a scarcity of detailed randomized studies comparing the two blocks, therefore, we compared their efficacy in terms of duration and quality of pain relief.
| Methods|| |
The study was approved by the Ethical Committee of Jawaharlal Nehru Medical College, Aligarh Muslim University, Aligarh, India, with reference number REF/2020/05/033494 and registering trial online on the Clinical Trial Registry-India with registry code CTRI/2020/05/025439.
Seventy female patients were assessed for eligibility, out of which 5 did not meet the inclusion criteria and 5 declined to participate. A prospective randomized study was conducted on 60 adult female patients undergoing elective breast surgeries (MRM) under general anaesthesia from November 2018 to September 2020 at the Department of Anaesthesiology and Critical Care of an academic teaching hospital [Figure 1]. The patients were divided into two groups of 30 each using a computer-generated random number table. Allocation concealment was done by serially numbered opaque sealed envelopes technique. The sealed envelopes were opened on the day of surgery by a person not participating in the study. Group P received USG-guided PEC II block and Group S received USG-guided SAP block. Female patients between 20 and 70 years of age, weighing 35–80 kg, American Society of Anaesthesiology (ASA) 1 and 2 and undergoing elective breast surgeries were included in the study. Written informed consent was taken. Patients not giving consent, undergoing bilateral breast surgeries, history of opioid allergy, coagulation disorder, skin infection at the puncture site, hepatic or renal disorders were excluded.
Patients were premedicated with injection midazolam at a dose of 0.03 mg/kg IV, injection dexamethasone 0.15 mg/kg IV and injection fentanyl 1.5 mcg/kg IV. Perioperative monitoring was done by electrocardiogram, pulse oximeter, noninvasive arterial blood pressure, temperature and capnography. After preoxygenation for 3 min., anaesthesia was induced with injection propofol 2 mg/kg IV and neuromuscular blockade was achieved with injection vecuronium 0.1 mg/kg IV. Then orotracheal intubation was done with an appropriate sized cuffed endotracheal tube. Anaesthesia was maintained with oxygen, nitrous oxide, intermittent doses of injection vecuronium and isoflurane.
After induction of general anaesthesia before the incision, under strict aseptic precaution, the blocks were performed with the patient supine and ipsilateral arm abducted 90°. With standard ASA monitoring, a linear ultrasound transducer (6–13 MHz) was placed over the Coracoid process in the paramedian sagittal plane. The transducer was then rotated slightly such that the caudal border moved laterally and the proximal border remained unchanged. This rotation helps image the Pectoral branch of the thoracoacromial artery. In Pec II block first injection was given at the Anterior axillary line at the level of the fourth rib between Pectoralis minor (Pm) and Serratus anterior (SA) and second injection between PM and Pm muscle. For this, a 22G spinal needle was introduced and advanced in an in-plane approach. A hypoechoic layer was created upon injection of 2 ml normal saline followed by infiltration of the total volume of 0.25 ml/kg of 0.25% Levobupivacaine with half of the calculated volume given between Pm and SA and the other half in between PM and Pm muscle on the same side of the breast with intermittent aspiration. Correct placement of the needle was confirmed by the expansion of local anaesthetic solution as a dark shadow between Pm and SA and similarly between PM and Pm muscles as shown in [Figure 2].
|Figure 2: Pectoral nerve block II block before, (a) and after, (b); serratus anterior plane block before, (c) and after, (d) (Pectoralis minor -Pectoralis Major, -Pectoralis Minor, -Latissimus Dorsi, -Serratus Anterior)|
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SAP block was performed with the patient supine and the ipsilateral arm abducted 90°. Counting ribs from the clavicle while moving the transducer laterally and distally until fourth and fifth ribs were identified. SA muscle, thick hypoechoic muscle deep to latissimus dorsi (LD) was imaged over the ribs. Translating the transducer posteriorly facilitated the identification of plane between SA and LD muscle. A 22G spinal needle was introduced and advanced in an in-plane approach. A hypoechoic layer was created upon injection of 2 ml of normal saline followed by infiltration of 0.25 ml/kg of 0.25% Levobupivacaine between SA and LD on the same side of the breast.
Correct placement of the needle was confirmed by the expansion of local anaesthetic solution as a dark shadow between SA and LD muscles as shown in [Figure 2].
After completion of surgery residual neuromuscular paralysis was reversed using injection neostigmine 0.5 mg/kg and injection glycopyrrolate 0.01 mg/kg. After extubation, the patients were shifted to the postanaesthesia care unit (PACU) to watch for any haemodynamic compromise. The patients and all the staff involved in the data collection were blinded to the group assignment.
The patients were monitored until they became fully awake and oriented to time, place and person. The first recording was done at this point and it was called 0 h. Then the parameters were recorded at 2 h, 6 h, and 24 h. Both the groups of patients were shifted to the surgery high dependency unit after 30 min of the procedure. All patients received injection diclofenac sodium 1.5 mg/kg IV over 10 min when numeric rating scale (NRS) >3 in the postoperative period at a minimum interval of 6 h. Injection nalbuphine 0.1 mg/kg IV was kept for breakthrough pain with NRS >3 and not subsided by injection diclofenac. The primary objective was to compare the duration of pain relief whereas the secondary objectives were to compare the degree of pain relief, postoperative analgesic requirement within 24 h after the completion of the surgery, patient satisfaction score and complications if any. Incidence of PONV was also recorded during 24 h postoperatively. PONV was assessed by 4 point scoring system at 0 h, 2 h, 6 h, 24 h as none = 0, nausea = 1, retching = 2 and vomiting = 3. Patient satisfaction score during the postoperative period was noted by Likert's scale. The scale included 5 Likert items: Very dissatisfied = 1, dissatisfied = 2, unsure = 3, satisfied = 4 and very satisfied = 5. Patients were enquired to verbally assign the score of the satisfaction scale.
Statistical analysis was done by using IBM SPSS version 22. (SPSS Inc., Chicago, IL, USA). Considering the alpha cut-off of 0.05 and power of 80% and (d = μ1 − μ2 = 1.2), Zα/2 is dependent on the level of significance which for 5% this is 1.96, Zβ: Is dependent on power and for 80% this is 0.84; so 30 patients in each group was calculated.
Having obtained informed written consent, 60 patients who were initially considered candidates for MRM, were assigned to the study.
Patients demographic characteristics were analysed using unpaired t-test and Chi-squared test. The results were expressed in numbers, percentages, mean and standard deviation as appropriate. Haemodynamic parameters HR, BP and NRS, PONV score, total Diclofenac required in 24 h and patient satisfaction score were analysed by using unpaired t-test and Chi-square test. A P < 0.05 was considered statistically significant.
| Results|| |
Demographic data like age, weight, height were comparable in both the groups [Table 1]. The mean time to the first dose of analgesic given was 826 ± 405.24 min. in Group P and it was 1280 ± 264.29 min in Group S. This was statistically significant (P < 0.001) [Table 2]. The mean total Diclofenac sodium requirement in 24 h was 155.67 ± 80.46 mg in Group P and it was 84 ± 36.07 mg in Group S. The difference was statistically significant (P < 0.001) [Table 2].
The mean NRS score at rest at 0 h and 2 h were comparable. There was a significant difference in the mean NRS score at 6 h. It was 2.57 ± 1.07 in Group P and 1.73 ± 0.91 in Group S (P = 0.002). The mean NRS score at 24 h was 1.57 ± 0.5 in Group P and it was 1.33 ± 0.48 in Group S, the difference was statistically not significant (P = 0.071) [Table 3]. The mean NRS score on movement at 0 h, 2 h, 6 h and 24 h was compared between Group P and Group S. The mean NRS Score on movement at 2 h and 6 h in Group P was significantly more compared to Group S with P = 0.002 at both the periods. No statistically significant difference was found at 0 h and 24 h [Table 3].
There was no significant difference between the groups in the incidence of PONV [Table 4]. The mean patient satisfaction score was 3.3 ± 0.47 in Group P and it was 3.7 ± 0.47 in Group S with a statistically significant difference (P = 0.002). The incidence of adverse drug effects during 0–24 h postoperatively was recorded in both groups. The incidence of headache was comparable (P = 0.50) and pruritus was not seen in any of the groups. No other complications were noted in the two groups.
| Discussion|| |
There has been a significant reduction in the use of analgesics and duration of hospital stay with the use of more recent regional block techniques which has led to the maintenance of haemodynamic stability and early ambulation. PEC block technique was first described by Blanco et al., in 2011–2012 and is of two types; Pec I and Pec II. In PEC I block, the anaesthetic drug is infiltrated between PM and Pm muscles blocking Medial and Lateral Pectoral nerve innervating PM muscle. Pec II is an extension of Pec I block involving second injection lateral to Pec I injection point in the plane between Pm and SA muscles providing blockade of lateral branches of T2-T4 spinal nerve for surgeries like Mastectomy and Radical Mastectomy. The Pec I block is a superficial block that has been used effectively for surgical procedures such as placement of breast expanders and subpectoral prosthesis, shoulder surgery with deltopectoral groove involvement and insertion of a pacemaker or intercostal drain.
The Pec II block favors mastectomy and axillary clearance because it also blocks long thoracic and thoracodorsal nerves in addition to the lateral branches of the intercostal nerves that exit at the level of the mid-axillary line innervating the mammary gland and the skin from T2 to T6. SAP block was also described by Blanco et al. in 2013 which is a more recent, safe and easily performed technique. In this block anaesthetic drug is infiltrated between SA and LD muscles blocking lateral branches of intercostal nerves from T2-L2 for, analgesia in surgeries like Thoracotomy and Radical Mastectomy.
In our study, 60 female patients of age between 20 and 70 years undergoing elective breast surgeries under general anaesthesia were randomly allocated into 2 groups with a computer-generated random number table, Group P and Group S of 30 each. Group P received USG guided PEC II block and Group S received USG guided SAP block. Mean time of the first analgesic requirement was noted and it was found to be significantly more in Group S than Group P. Thus, SAP block had a prolonged duration of analgesia as compared to PEC II block. In both the groups, it was seen that patients required no analgesic at 2 h postoperatively. Moreover, no patient in the two groups required Injection of Nalbuphine for breakthrough pain. Our study was consistent with another study done by Rhimzadeh et al. which was conducted on 60 patients undergoing mastectomy. They found that the time to the first patient-controlled analgesia request was remarkably longer in the SAP group than in the control group with no block given.
Mean total Diclofenac required in the first 24 h period was significantly more in Group P than Group S. This was consistent with a study done by Khalil et al. who found less Morphine consumption in the early postoperative period with SAP block compared to Thoracic Epidural analgesia for post Thoracotomy pain relief.
NRS scores at rest in both the groups were comparable at 0, 2 and 24 h. The difference in NRS score at rest between the two groups was statistically significant at 6 h. The mean NRS score during movement at 2 h and 6 h was significantly more among Group P compared to Group S. No statistical difference was found at 0 h and 24 h. This implies that SAP block is more effective in providing analgesia at 6 h at rest and 2 and 6 h on movement resulting in early ambulation. Khalil et al. also found that SA Plane block appeared to be an effective alternative for postoperative analgesia after thoracotomy, as it provided low pain scores in the early postoperative period.
Two patients (6.67%) out of 30 in Group P suffered from nausea whereas in Group S only 1 patient (3.33%) experienced nausea both at 2 h postoperatively and the difference was comparable (P = 0.89). No incidence of PONV was recorded at any other point of time postoperatively. This was consistent with a study done by Yao et al. who found reduced incidence of PONV and the PACU discharge time in the SAP group compared to the control group which received physiological saline.
The mean patient satisfaction score was 3.3 in Group P whereas it was 3.7 in Group S and the difference in patient's satisfaction score between the two groups was statistically significant (P = 0.002) due to a prolonged pain-free period. Yao et al. compared the SAP group with the control group which received physiological saline and also found higher satisfaction scores in the SAP group.
Only 1 patient out of 30 in Group P had an episode of headache and none had a headache in Group S. In both the groups no other complication like pruritis, local anaesthetic toxicity or allergy, pneumothorax or infection was noticed. The overall incidence of adverse drug effects during 0–24 h postoperatively was comparable (P = 0.50) in both the groups. Khalil et al. also found that SA Plane Block appeared to be safe as it provided no noteworthy complications.
Bakeer et al. recently conducted a study in 2020 comparing PEC II and SAP blocks with a control group receiving no block in patients undergoing MRM for breast cancer. The blocks were associated with reduced intraoperative fentanyl requirements, Visual Analog Scale scores, and PONV as compared with the control group. Furthermore, the blocks were associated with prolonged time to first rescue analgesia and better sedation scores in comparison with the control group. However, there were no significant differences between both blocks for all outcomes.
This difference in findings may be attributed due to several reasons. The first reason may be that the volume used was 30 ml of 0.25% in each group whereas in our study it was taken as per the weight of the patient in a dose of 0.25 ml/kg of 0.25%; second, in our study learning curve was achieved by performing at least 10 USG guided SAP blocks and Pec II blocks before the start of the study, then blocks were performed by that single experienced anaesthesiologist, under real-time ultrasound guidance and lastly, maybe due to the difference in sample size. Thus, we believe that the majority of SAP blocks were successfully administered in our study while nothing was mentioned in the above study about the expertise of the person performing the block or whether it was done by the same or different person each time.
So, in our study SAP block appeared to have a better analgesic profile when added to general anaesthesia in patients undergoing MRM. It was characterized by lower NRS scores and reduced postoperative analgesic consumption than general anaesthesia alone. In line with the current study, PONV and sedation scores were also lower in the SAP group. Furthermore, ultrasound-guided SAP block is a safe and easy-to-learn technique, due to the visualisation of distinct bony landmarks. It can be performed safely under deep sedation or General anaesthesia to avoid undue anxiety. No block related complications such as local anaesthetic toxicity and pneumothorax were noted in this study. These findings can be explained by the fact that SA blocks target the thoracic nerves more selectively than pectoral blocks.
Our study had certain limitations that are small sample size, lack of a control group receiving placebo injection, there was no long-term follow-up for the incidence of chronic pain, we did not test the effectiveness of the blocks by checking for loss of sensations like cold and pinprick tests as the blocks were performed after induction of anaesthesia.
Since, few studies have examined the effect of SAP on patients undergoing MRM in postoperative pain management, to improve the power of results by this block, larger studies are recommended to be done using other drugs and doses, infusion through a catheter insertion with an even larger sample sizes. The comparison of the efficacy of this method with other regional blocks on acute and chronic pain management is also recommended.
| Conclusion|| |
Ultrasound-guided SAP block provides better postoperative analgesia both in terms of quality and duration over PEC II. SAP block reduces the analgesic demand, thus improving overall patient satisfaction.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4]