Comparıson of Analgesıc Effıcacy of Dıfferent Volumes of Serratus Posterior Superıor Intercostal Plane Block After Modıfıed Radıcal Mastectomy Surgery

Comparıson of Analgesıc Effectıveness of Dıfferent Volumes of Serratus Posterıor Superıor Intercostal Plane Block In Patıents Undergoıng Modıfıed Radıcal Mastectomy Surgery

The aim of researchers is to compare the effects of three different local anesthetic concentrations and volumes on opioid consumption, postoperative analgesic efficacy, and pain scores during ultrasound-guided SPSIP blocks in patients undergoing modified radical mastectomy. Additionally, we aim to map and identify the dermatomal areas where different concentrations and volumes of SPSIP blocks provide analgesia.

The researchers' hypothesis is that a lower concentration but higher volume of SPSIP block could provide similar analgesic efficacy to a higher concentration and lower volume block, while also improving the safety profile in terms of local anesthetic systemic toxicity by reducing the total local anesthetic load. In other words, we believe that using less than the 0.25% bupivacaine used in previous studies on this block could provide similar analgesic efficacy. This is because, in fascial plane blocks, separating the fascia is as important a technique as the local anesthetic administered. Facial plane blocks are volume-dependent blocks.

The Modified Aldrete scoring system is a routine assessment performed in our clinic's postoperative recovery room to determine whether a patient has recovered. Patients with an NRS score of 4 or higher, despite routine analgesia, will receive 50 mg tramadol hydrochloride as a rescue analgesic, administered intravenously over 30 minutes in 150 ml of saline solution.

Inclusion Criteria:

• The study included adult patients over 18 years of age who underwent modified radical mastectomy under general anesthesia and were classified in risk groups I-II-III according to the American Society of Anesthesiologists (ASA) risk classification.

Exclusion Criteria:

• patients with coagulopathy,
• patients with signs of infection at the block application site,
• patients with ASA IV
• patients with known allergies to any of the study drugs,
• patients with ineffective block
• patients who could not cooperate during postoperative pain assessment
• patients who wanted to withdraw from the study,
• patients with alcohol and drug addiction,
• patients with musculoskeletal abnormalities
• patients with kidney and liver failure
• patients with obesity (body mass ≥ 35 kg/m2)