Incidence and Clinical Features of Breakthrough Pain After Brachial Plexus Block in Diabetic Patients

This observational study aims to determine the incidence and clinical characteristics of rebound-breakthrough pain after ultrasound-guided brachial plexus block in adult patients with type 2 diabetes mellitus. Adult patients undergoing elective upper-extremity surgery are divided into a type 2 diabetes group and a non-diabetic control group. Baseline clinical data and pain-related outcomes are collected after nerve block. This work may provide evidence for optimizing perioperative pain management for diabetic patients receiving brachial plexus block.

Inclusion Criteria: * Aged 18 years or older * Undergoing elective upper-extremity surgery * Planned for ultrasound-guided brachial plexus block with 0.375% ropivacaine * Able to cooperate with pain assessment and follow-up within 48 hours after block * Written informed consent obtained Exclusion Criteria: * Allergy or contraindication to amide-type local anesthetics * Pre-existing peripheral neuropathy of the affected upper limb * Chronic regular use of opioids before surgery * Coagulopathy or infection at the block puncture site * Cognitive dysfunction unable to complete NRS pain evaluation * Pregnancy or lactation * Incomplete clinical data expected during follow-up