Pain Management in Children Undergoing Supracondylar Humerus Fracture Repair: Can a Local Supraclavicular Block Improve Their Postoperative Outcome?

Forty six American Society of Anesthesiologists (ASA) class I or II patients between the ages of 2 and 10 years undergoing reduction of supracondylar humerus fractures will be enrolled in the study. From mid-May to the beginning of August, Lurie Children's (formerly Children's Memorial Hospital)historically has 50-70 supracondylar humerus fractures in children, and we expect an 80% recruitment rate for the study. A power analysis estimated that a sample size of 46 patients would have an 80% power at the 0.05 level of significance to detect a 50% reduction in the number of patients requiring rescue medication when comparing intravenous opioids and the ultrasound-guided supraclavicular nerve block (from approximately 80% to 40%).

After obtaining informed consent, the patients will be taken to the operating room where the procedure will be performed. Intraoperatively, patients will be randomly assigned to be in one of two groups. Randomization will be determined by block allocation with a 1:1 ratio with permuted, mixed blocks of 4 and 6 created randomly using a computer based randomization table. Randomization will be performed by one of the co-investigators. Preoperatively, patients will be assessed for neurovascular status by testing the patient's ability to make three movements: thumb extension (radial nerve), proximal interphalangeal joint (PIP) flexion (median nerve), and interossei function (ulnar nerve). Patients may be removed from the study after consent is given if removal of the cast prior to surgery reveals excessive swelling in the elbow, indicating an increased likelihood for development of compartment syndrome postoperatively. This determination will be made by the attending orthopaedic surgeon performing the procedure. Patients with an increased likelihood of developing compartment syndrome will be given narcotics to treat pain.

All patients will undergo a general anesthetic for the surgical procedure. Surgical anesthesia will be maintained using volatile anesthetics. Intraoperatively, while still under general anesthesia, Groups 1 and 2 will receive a standardized intravenous dose of 0.05 mg/kg of morphine in a total volume of 1 ml. Following injection of morphine, an ultrasound-guided supraclavicular nerve catheter (Angiocath) will be placed in Group 2. All catheters will be placed by one of the anesthesiologist trained in regional pain control using a 25 mm linear US probe in a sterile fashion.

Patients will be taken to the postoperative recovery room (PACU) area where they will be tested for nerve function after emergence from anesthesia. If the examination is unchanged from preoperative assessment, an injection block using 5 ml of 0.25% bupivacaine with 1:200,000 epinephrine will be administered. Bupivacaine is a long acting local anesthetic that prevents nerve conduction and action potential initiation by decreasing the permeability of the neuronal membrane to sodium. We use a maximum dose of 5 mL of 0.25% bupivacaine, and we usually base the dose on a ml/kg (0.2 ml/kg) with a maximum dose not to exceed 2.5 mg/kg. This will be well below toxic levels. A band-aid will be placed on all patients where a supraclavicular nerve block would have been inserted, and parents will be asked to leave the band-aid on for 3 days to maintain the blindness to the treatment type by the patient.

In the PACU, the patient will be evaluated for pain and discomfort by a member of the research team using the "Faces Pain Scale-Revised (FPS-R)" Other side effects such as nausea, vomiting, somnolence and respiratory depression will be noted. Any incidence of nausea and/or vomiting will be treated with 0.1 mg/kg (up to 4 mg) of ondansetron given intravenously.