Background

Breast cancer is now the most common cancer in most cities in India, and the second most common in rural areas. In India, 1,44,937 women were newly detected with breast cancer in year 2012.

As the number of breast cases are increasing; so are increasing the number of surgeries, henceforth incidence of acute pain, conversion of acute pain to chronic pain and breast cancer recurrence. Hence by offering reduction in post operative pain in these patients, the recovery is enhanced, discharge is early, there is decreased associated risk of ileus, thromboembolism, myocardial infarction, immune and pulmonary dysfunction. 

Body’s response to surgical stress causes the release of chemical mediators, which determine up regulation of malignant pathways, disruption of tumor homeostasis and promotion of cancer recurrence.

Study design

This is a Prospective, single blindedRandomized controlled trial to compare pectoral nerve block with control for acute post operative pain management in patients undergoing modified radical mastectomy, to be carried out at Tata Memorial Centre.

Methodology

Informed and written consent would be taken from patients scheduled for modified radical mastectomy, who comply to the inclusion criteria. Demographic data will be recorded and numerical rating pain score (NRS; 0–10, 0 = No Pain, 10= Worst Pain) will be explained to the patients. They will be randomly allocated into two equal groups according to the computer generated sequence.

Patients in both the groups will be given general anaesthesia. In the operation theatre, standard monitors will be attached. Peripheral intravenous access will be secured by 22G cannula. After preoxygenation with 100% oxygen, induction will be done using inj. fentanyl 2 mcg/kg and inj. propofol 2mg/kg and after assessing adequate mask ventilation, non depolarizing neuromuscular blocking agent will be administered.  The airway will be secured by using laryngeal mask airway of appropriate size and anaesthesiamaintained using O2+Air+ Isoflurane.

Group I (PEC group = 30 patients) will receive ipsilateral Pectoral nerve block I & II under ultra sonographic guidance by experienced anaesthesiologist (ie consutant or senior resident who  are trained in regional blocks technique; and junior resident who has performed at least five regional blocks under guidance of senior anesthesiologist)¹² post induction,  while the group II (CONTROL group =30 patients) will directly proceed to surgery. Both the groups will receiveInj. Fentanyl 25mcg, if there is intraoperative rise in heart rate &/or blood pressure by 20% above preoperative baseline.All patients will receive injparacetamol 15mg/kg and Inj. Ondansetron at the time of wound closure. No other analgesic except Inj. Fentanyl boluses and single dose of inj. Paracetamol will be given intraoperatively. Total dose of fentanyl givenintraoperatively will be noted. After recovery from anesthesia, patients will be shifted topost-anesthetic care unit (PACU) /recovery where pain will be assessed as explained later.

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

To perform Pectoral nerve block, the patient is positioned supinewith the ipsilateral arm abducted andexternally rotated.Taking complete aseptic precautions, after cleaning and draping the infraclavicular and axillary area,linear ultrasound (US) probe with frequency of 5 -13 hertz is placed at infraclavicular region and moved laterally to locate the axillary artery and vein directly above 2^nd rib,along with identification of pectoralis major and pectoralis minor muscles. The skin point of puncture is infiltrated with 2 ml of 2% lignocaine,23 G spinal needle isthen inserted in plane with US probe into the fascial plane and 10 ml of inj. bupivacaine 0.25% is injected between the pectoral muscles. Then, the US probe is moved toward axilla till serratus anterior muscle is identified above 3^rd and 4^th ribs then the needle is reinserted into the fascial plane between pectoralis minor muscle and serratus anterior muscle and 20 ml of inj. bupivacaine 0.25% is injected.

Assessment of outcome

Assessment in recovery room will be done by recovery room anesthesiologist and in wards by Acute pain service ( APS ) team. Pain scores will be noted at rest as well as movement after shifting the patient to recovery denoted as time zero. Subsequently, pain scores will be noted at 2,4,6,12,18,24 hours or discharge whichever is earlier.Also, the pain scores and time when rescue analgesia is demanded will be noted.

Nausea and vomiting will be measured as yes (Y) or no (N) at above times. Nausea and vomiting will be treated with IV antiemetics.

Patient Satisfaction will be measured as poor=0, fair = 1, good =2, excellent = 3, at 24 hours post operative or at discharge, whichever is earlier.

Data Analysis

Demographical data and Scales computed for each domain score will be presented as mean (Standard Deviation), median, range and percentage. Categorical data will be analyzed using the chi-square test or Fishers Exact test (for binary data). Comparisons of pain scores for the first 24 hours ( at 0,2,4,6,12,18 and 24hours) of the two  groups will be analyzed using the Independent sample t test or  Mann-Whitney U  test as per the distribution of data. P-value < 0.05 will be considered statistical significant.

Sample Size:

Calculation of sample size based on a preliminary observational study involving 24patients undergoing unilateral non reconstructive mastectomies in Tata MemorialCentre in which, mean pain scores in the immediate post-operative period were assessed.The mean postoperative pain score was found to be 6.5/10 on movement according toNumerical Rating Scale, which is moderate to severe pain (0-No pain, 1-3 mild pain, 4-6 moderate pain, 7-10 severe pain). Assuming that a reduction of score by 30%, (i.e, areduction by 2 units on the numerical rating scale would convert this pain from themoderate range to the mild range) will be significant, a value of 30 patients in each ofthe 2 groups was calculated.

Aims and Objective

Aim

To evaluate the efficacy of Pectoral Nerve Block for post operative analgesia in breast surgery patients.