The optimal analgesic peripheral nerve block (or combinations thereof) are undefined for clavicle fractures, the most frequent fracture in the human population. This goal of this study is to determine whether interscalene block (ISB), superficial cervical plexus block (SCPB), or both provide the best analgesia for lateral and midshaft clavicular fractures, respectively.

Clavicle fractures are relatively common injuries that occur most often in young active males and elderly individuals. They are often a result of direct trauma to the shoulder, typically from a fall. Clavicle fractures represent 5-10% of all fractures and represent the most frequent fracture in the human population. Midshaft fractures account for 69-85% of the clavicle fractures, distal shaft fractures 12-28%. (1) Analgesia for clavicle fractures can be challenging for anaesthetists secondary to the complex and varied innervation in this region. Literature describing the innervation of the clavicle and overlying skin is heterogeneous with the C3 to C6 nerve roots being involved. The clavicle itself has been reported to be innervated either by C4 or by C5 and C6 (subclavian nerve) nerve roots. (2) Regional anaesthesia for intraoperative and postoperative analgesia of clavicle fractures employs several possible, commonly used approaches. The contemporary literature surrounding the optimal regional anaesthetic technique for clavicle surgery which can provide superior postoperative analgesia and minimize systemic agents intraoperatively is lacking Currently there are only small case series or case reports published. Peripheral nerve blocks used to anesthetize the clavicle include SCPB, ISB, and combined SCPB-ISB. Larger, systematic trials have not yet been performed to our knowledge and as recently as one year ago a call for more evidence in this area of regional anaesthesia was published in the American Society of Regional Anesthesia and Pain Medicine. The purpose of this study is to compare analgesic outcomes after the common regional anesthetic techniques (ISB versus SCPB versus both).

Inclusion Criteria:

• undergoing open reduction and internal fixation of clavicle fracture (midshaft or lateral)

Exclusion Criteria:

• lack of patient consent
• contra-indication to upper extremity peripheral nerve block (eg. severe pulmonary dysfunction)
• inability to lie supine for nerve block
• polytrauma
• pre-existing neurologic deficit in operative upper extremity
• allergy to amide local anesthetic
• contralateral phrenic nerve dysfunction
• chronic opioid use (>30mg daily oral morphine equivalent)

All parties will be blinded except for the specific anesthesiologist performing the nerve blocks. This person will not be involved in providing further care (administering anesthesia) nor data collection.