Postoperative pain is a significant problem in patients undergoing arthroscopic shoulder surgery. This situation disrupts the patient's comfort and affects the functional outcome after surgery by preventing early rehabilitation. Various methods are used for postoperative pain control. Intravenous opioid agents are one of the most commonly used analgesic techniques. However, opioids can cause undesirable side effects such as respiratory depression, sedation, constipation, allergic reactions, nausea, and vomiting. Therefore, alternative techniques are needed to reduce opioid use.

Serratus posterior superior interfascial plane block (SPSIPB) is a novel interfascial plane block described by Tulgar et al in 2023. It is based on injection into the serratus posterior superior muscle at the level of the 2nd or 3rd rib. This block provides analgesia in cases such as interscapular pain, chronic myofascial pain syndromes, scapulocostal syndrome, and shoulder pain. It has been reported that SPSIPB provides effective shoulder analgesia.

Postoperative pain is a significant problem in patients undergoing arthroscopic shoulder surgery. This situation disrupts the patient's comfort, prevents early rehabilitation, and affects the functional outcome after surgery. Various methods are used for postoperative pain control. Intravenous opioid agents are one of the most commonly used analgesic techniques. However, opioids can cause undesirable side effects such as respiratory depression, sedation, constipation, allergic reactions, nausea, and vomiting. Therefore, alternative techniques are needed to reduce opioid use. Regional techniques can be used for postoperative pain treatment following arthroscopic shoulder surgery. Ultrasound (US)-guided serratus posterior superior block (SPSIPB) is a novel interfascial plane block described by Tulgar et al in 2023. It is based on the principle of injection into the serratus posterior superior muscle at the level of the 2nd or 3rd rib. This block provides analgesia in cases such as interscapular pain, chronic myofascial pain syndromes, scapulocostal syndrome, and shoulder pain. The SPS muscle is located at the C7-T2 level. It attaches to the lateral edges of the second and fifth ribs. It is innervated by the lower cervical and upper intercostal nerves. Analgesia is provided by blocking these nerves with the SPS block. Tulgar et al. reported in their cadaver study that the spread of the serratus posterior superior interfascial plane block; staining in the superficial fascia of the trapezius muscle was observed only on the left side at the 7-10th intercostal levels, but not on the right. There was significant staining deep in the trapezius muscle on both sides. Both the surface and the skin of the rhomboid major were clearly stained, while only the skin of the rhomboid minor was stained; SPSP block will provide successful analgesia in procedures involving the thoracic region such as breast surgery, thoracic surgery, and shoulder surgery.

In this study, the investigators aim to evaluate the analgesic efficacy of SPSIPB by comparing the control group in patients who underwent arthroscopic shoulder surgery.

Inclusion Criteria:

• American Society of Anesthesiologists (ASA) classification I-II
• Scheduled for arthroscopic shoulder surgery under general anesthesia

Exclusion Criteria:

• history of bleeding diathesis,
• receiving anticoagulant treatment,
• known local anesthetics and opioid allergy,
• infection of the skin at the site of the needle puncture,
• patients who do not accept the procedure

We will not plan to share IPD

The patient and the anesthesiologist who performs postoperative pain evaluation will not know the group.