Breast cancer is the most common malignancy in women at worldwide. Even a minor breast surgery can cause significant postoperative pain (PP) (1). PP could be converted into chronic pain in 25-40% of cases. Inadequate PP control is associated with increased morbidity, delay in wound healing, prolonged hospital stay, increased opioid use, increased side effects and high cost of care. For these reasons, regional anesthetic techniques are recommended for effective PP management. Some of recent studies suggest that ultrasound-guided pectoral I (PI), pectoral II (PII) and serratus plan block (SPB) may be an alternative to thoracic epidural analgesia and paravertebral block applications because of the ease of administration, low side effect profile and adequate analgesia in breast surgery. (2,3).

In breast surgeries, the serratus plane block has recently been described and rapidly became popular. The serratus plane block is called the modified pectoral II block. Local anesthetic drugs are injected onto the serratus muscle by targeting thoracodorsal nerve, thoracicus longus nerve, lateral and anterior branches of the T2-T9 intercostal nerves. In the pectoral I (Pecs I) block, the medial and lateral pectoral nerves of the brachial plexus are targeted. Additionally, Pecs I block can be effective for analgesia in axillary dissection. In the literature, there are studies comparing pectoral I + II blocks and serratus plane block in terms of analgesic efficacy in breast surgery. The aim of this study was to evaluate the postoperative analgesic efficiency of serratus plane block and serratus plan block plus pectoral I block combination.

Participans will be informed about the potential benefits and complications after the study protocol has been fully and thoroughly explained. After premedication with 0.03 mg / kg iv midazolam, participans will be noninvasively monitored by taking into the operating room (heart rate, blood pressure, pulse oximetry). Anesthesia induction will delivered with fentanyl 1mcg / kg, propofol 1.5-2 mg / kg and rocuronium 0.5 mg / kg. The maintenance of anesthesia will be achieved by infusion of sevoflurane 1-3% in 50% O2/50% medical air. The depth of anesthesia will be evaluated with bispectral index monitoring and will be kept between 40 and 60.. Thirty minutes before end of the surgery, all patients were intravenously administered 20 mg tenoxicam HCl and 1gr paracetamol.

SPB plus Pecs I block technique: Bupivacaine/lidocaine mixture will be injected onto the serratus muscle and injected between the pectoralis minor/pectoralis major muscles.

SPB technique: Bupivacaine/lidocaine mixture will be injected onto the serratus muscle.

After the surgery, 1 g paracetamol was intravenously administered once every 8 h. Postoperative pain was assessed using VAS (VAS 0 = no pain, VAS 10 = most severe pain ). Morphine 0.1mg / kg will be used as rescue analgesic drug.Duration at PACU was recorded right from 0 h. VAS scores at 0, 1,2, 6, 12 and 24 h were recorded. PONV was evaluated using a numeric ranking scale (0 = no PONV, 1 = mild nausea, 2 = severe nausea or vomiting once attack, and 3 = vomiting more than once attack). If PONV score was >2, the antiemetic metoclopramide Hcl 10mg was intravenously administered.

Inclusion Criteria:

1. ASA 1-2-3
2. Patients scheduled for elective surgery

Exclusion Criteria:

1. Previous neurological disease symptom (TIA, syncope, dementia, etc.)
2. Allergy to drugs
3. Major cardiac disease
4. Renal failure
5. Psychiatric disease
6. Patients who refuse to participate in the study