Shoulder arthroscopy is the standard surgical procedure for rotator cuff injury treatment. Compared with open shoulder joint surgery, it has the advantages of safety, minimal invasiveness, and ease of operation, and has been widely used in clinical practice. Nerve block is an ideal anesthetic technique for shoulder joint surgery. Moreover, with ultrasound-guided block, the operation is visualized, which is of great significance in improving the success rate of anesthesia block and reducing the incidence of postoperative complications. However, clinical practice has also shown that nerve block can cause diaphragmatic paralysis, and the incidence of diaphragmatic paralysis varies among different nerve block approaches. Diaphragm activity is affected in patients with neuromuscular system diseases. To ensure the safety of extubation after surgery, it is necessary to assess the diaphragm in patients before anesthesia and after surgery. At present, there are relatively few research reports on the application of ultrasound-guided superior trunk block (STB) anesthesia in rotator cuff repair.

To investigate the effect of ultrasound-guided brachial plexus STB anesthesia on the incidence and muscle strength of unilateral diaphragmatic paralysis in patients undergoing arthroscopic rotator cuff repair.

A total of 92 patients who underwent elective shoulder joint surgery at Sichuan Orthopedic Hospital from March 2023 to March 2024 were selected and randomly divided into a control group and an observation group, with 46 cases in each group. The control group was given intravenous general anesthesia combined with brachial plexus nerve block via the supraclavicular approach, while the observation group was given intravenous general anesthesia combined with STB. The diaphragmatic mobility and diaphragmatic paralysis rate of the two groups were compared before the block and 30 minutes after the block. The blood gas indices were recorded before nerve block (T0) and 30 minutes after surgery (T1). The blocking effect and muscle strength of the patients were recorded, and the safety of anesthesia was evaluated.

Thirty minutes after block, the diaphragmatic mobility during deep breathing and calm breathing in the observation group was less than that in the control group (P < 0.05), and the incidence of diaphragmatic paralysis in the observation group was lower than that in the control group (P < 0.05). The duration of motor block in the observation group was shorter than that in the control group (P < 0.05). There was no statistically significant difference in blood gas parameters between the two groups at any time point (P > 0.05). The elbow flexion and wrist flexion muscle strength of the observation group at 12, 24, and 48 hours after the operation were all higher than those of the control group (P < 0.05). There was no statistically significant difference in adverse reactions between the two groups (P > 0.05) .

Ultrasound-guided STB has a relatively mild impact on the flexion muscle strength of the upper limb, elbow, and wrist in patients undergoing arthroscopic rotator cuff repair of the shoulder. Moreover, it plays a more prominent role in protecting the diaphragm and reducing the incidence of diaphragmatic paralysis, which is worthy of clinical application.