The Patient-Reported Outcome of Intra-Operative Direct Vision Pectoral Nerve Block for Postoperative Analgesia for Breast Surgery

Background and Aims: Pectoral nerve blocks gained increasing recognition for adequate postoperative pain relief following breast surgery. Traditionally, anaesthetist administered preoperatively under ultrasound guidance, which added significantly to the total procedure time. We studied the effectiveness of intraoperative direct vision pectoral nerve block and reduction of total theatre time. Methods: We provided questionnaires to the eligible patients who underwent a mastectomy and or axillary node clearance from August 2018 to May 2019. All the patients had an intra-operative pectoral 1 and serratus plane (Pecs) block. Participants documented pain score twice daily, episodes of nausea or vomiting and type and dose of analgesia for the first seven postoperative days. We compiled and grouped the results into postoperative days 1 - 2 and 3 - 7 for data analysis. Results: Patients reported generally low levels of pain, with a median pain score of 1.75 out of 10 for postoperative days 1 - 2 (IQR 4). The score decreased to 0.7 for days 3 - 7 postopera-tively (IQR 3) suggesting that most patients had generally minimal levels of pain apart from a few outliers. The average injection time for PECs blocks was 5 minutes, significantly less than USS guided techniques of 20 - 30 minutes. Conclusions:


Introduction
Conventionally postoperative analgesia for breast surgery includes a multimodal approach with intra-operative infiltration of long-acting local anaesthetics like levobupivacaine, a combination of oral and intravenous paracetamol, nonsteroidal anti-inflammatory drugs (NSAIDS) and opioids when necessary. While general anaesthesia is still very commonly used for breast surgery, there has been a surge for regional techniques like pectoral nerve block 1 and serratus plane block (PECs block), paravertebral blocks and thoracic epidural techniques for analgesia, as well as a primary modality in patients who are high risk for anaesthesia [1]. Ultrasound-guided PECs block was described by Blanco et al. and has been very popular among anaesthetists [2] [3]. Although ultrasound-guided PEC1 and PEC2 blocks considered safe and provide significant intra and postoperative analgesia, there has been a case report of accidental infiltration to the brachial plexus resulting in short term numbness of the ipsilateral hand [4]. Single-shot PEC1 and PEC2 block and with or without further top-up in the postoperative period with the retained epidural catheters in both fascial planes also have been evaluated with randomised clinical trials [5] [6] [7]. Some of the studies have also revealed that pectoral and serratus plane block can reduce intraoperative fentanyl requirement, postoperative pain, postoperative morphine consumption, and postoperative nausea and vomiting (PONV) among those patients undergoing breast cancer surgery [8]. The Pecs block has been observed with fewer complexities and few complications when compared with thoracic paravertebral and thoracic epidural blocks in terms of analgesia quality [9] [10]. PEC II block has been efficient in providing pain relief among patients undergoing radical mastectomy. The present study has also presented the effectiveness of intraoperative direct vision pectoral nerve block and total theatre time reduction [11].
Ultrasound-guided PECs block was common practice in our hospital for the patients undergoing simple mastectomy with or without immediate reconstruction and for patients having axillary node clearance with wide local excision or mastectomy. When we audited our data regarding total theatre time, we had noticed that ultrasound-guided blocks required 20 -30 minutes extra time. While direct vision intraoperative PECs blocks have been described by Goswami [13].
Several publications, including metanalysis, showed PECs blocks were associated with less postoperative opioid use leading to shortened recovery time [7] [14].
We endeavoured to inject long-acting local anaesthetics (levobupivacaine) in the

Breast Innervation
The sensory innervation of the breast is carried by the lateral and anterior cutaneous branches of the 2nd through the 6th intercostal nerves. The sensation of the breast is derived from the dermatomes of breast development and is found to be segmented. The lateral mammary branches are responsible for supplying the skin covering of the breasts. The sensory anterior intercostal nerves are responsible for innervating the medial parts of the breast skin, while supraclavicular nerves do not contribute towards sensory innervation of skin covering in the breast [15]. The lateral branches of the 2nd intercostal nerve are responsible for the origin of the intercostobrachial nerve through the axilla to join the cutaneous nerve of the arm. The innervation of the nipple-areola complex and the central breast is derived from the anterior and lateral cutaneous branches of the 3rd, 4th, and 5th intercostal nerves [16].

Aims and Objectives
To study the effectiveness of intraoperative direct vision pectoral nerve block to provide adequate postoperative analgesia and reduction of total theatre time.

Method
We conducted this prospective observational study following approval from the clinical governance department. The anaesthetic team was informed and agreed with the intraoperative surgeon-led blocks.
We obtained informed consent from all the patients before surgery. The anaesthetic team was informed and agreed with the intra-operative surgeon led blocks. Patients undergoing breast cancer surgery were eligible for the study.
Age of entry was 18 or over. Mental capacity was assessed in the consent clinic prior to surgery. Information regarding the study were provided in the consent clinic and participation was voluntary.
All the patients undergoing simple mastectomy with or without axillary node clearance and all the patients who underwent axillary node clearance with or without simultaneous breast surgery from August 2018 to May 2019 were included.
Patients with arthritis, chronic back pain, fibromyalgia, or other chronic conditions, who were on regular non-opioid, steroids or opioid analgesics were excluded from the study. There was no age restriction in this study.
We explained the procedure to eligible patients at the consent clinic, and par- were given two separate questionnaires to complete. Participants were asked to record VAS pain score twice daily, type and quantity of analgesia and any episode of postoperative nausea or vomiting (PONV). Out of 43 questionnaires we distributed, 36 were completed and returned. We compiled and analysed the data after grouping them as postoperative days 1 -2 as group 1 and postoperative day 3 -7 as group 2.

Techniques of PEC1 and PEC2 Block
At the beginning of surgery patient's ipsilateral arm was abducted at an angle of ml each for both blocks. We took extreme care to avoid accidental injection to blood vessels or in the pleural cavity. The total procedure time was 5 minutes.
We did not experience any procedure-related immediate or delayed complication.

Statistical Method
Descriptive statistics have been used for analysing the questionnaire after grouping them as postoperative days 1 -2 as group 1 and postoperative days 3 -7 as group 2. The mean and standard deviation has been used in descriptive statistics for analysing the result. The median and interquartile range was calculated for pain score.

Results
It was observed that out of 43 participants, 36 returned the completed questionnaire. The mean age was 65 years, and the median was 70 with a range of 33 -84 years (   On 1 -2 postoperative day, the maximum percentage of the percentage of non-opioid analgesic used was 23.01% ranging from 0% to 75%. On 3-7 th postoperative day, the percentage of non-opioid analgesic used was 11.04% ranging from 0% to 50%. Mean opioid analgesic use on 1 -2 postoperative day was 4.09% ranging from 0% to 75%, and 2.06% on postoperative 3 -7 ranging from 0 to 50% (Table 3). Mean VAS scores on 1 -2 postoperative day were 2.08 and 1.58 on postoperative day 3 -7.
The most common non-opioid analgesic was paracetamol 1 gm up to four times a day. Only 23% of patients used 4 g of paracetamol per 24 hours within the first two postoperative days, and 77% of the patients had 3 g or less. On analysing data of day 3 -7 post-op days, only 11% were found to used 4 gm of paracetamol per days, leaving 89% of patients' pain was controlled with less than optimum doses.
The most common opioid analgesic was codeine phosphate tablets used by five patients (14%) in group 1 and 3 patients (8%) in group 2. The second most opioid analgesic was oral morphine solution 10 mg/10ml (Oramorph). Only two patients used as required oramorph along with paracetamol within the first two days of operation. There was no recorded use of oramorph in the 3 -7 days post-op group (Table 4). Following PEC1 and two blocks, patients experienced minimal pain which has been reflected in the mean pain score of 2.08 in the visual analogue scale (1 -10, where 1 was minimal pain or discomfort and 10 was very severe pain) in the postoperative day 1 -2. The mean pain score for postoperative day 3 -7 was 1.58. Median pain score for postoperative day 1 -2 was 1.75 and 0.7 for 3 -7 days (Table 5 and Figure 1). This indicated that apart from very few outliers, most patients had an incredibly low level of pain in the first week following surgery. There were no incidences of postoperative haemorrhage or pneumothorax in our series.

Discussion
Pectoral nerve blocks have become an essential tool in reducing postoperative pain in breast surgery. Blanco  of their subpectoral breast reconstruction and augmentation procedures [13].
They report that before introducing this nerve block, they routinely provided paracetamol, NSAID, and patient-controlled fentanyl postoperatively. Following the adoption of routine nerve blocks under direct vision, they found most patients declined opioid analgesia, managing satisfactorily with non-opioid alone.
We did not face any difficulty in the administration of direct PECs blocks.
There were no immediate or delayed procedure-related complications which made this procedure safe and effective. We were able to save at least 20 -25 of operating time by avoiding ultrasound-guided blocks. Although we did not use any indwelling catheter, our results were comparable to the study described by Goswami et al., who used indwelling epidural catheter for further analgesia [6].
The main strength of our study was prospective data collection, communication with the patient before and after surgery and completion of data collection

Funding
The work did not require any separate funding