While the SCP can reliably block pain fibers originating in the C4 root, it will not cover C5 or C6, which is necessary for complete coverage of all pain fibers from the clavicle. Post-operative pain relief has been achieved with SCP, but it is unclear if this would allow for complete surgical anesthesia/analgesia [14].

In order to achieve complete coverage of the pain originating from the clavicle, an interscalene block can offer increased coverage. Either nerve stimulation or ultrasound can be used to perform an interscalene nerve block, but the use of ultrasound compared to nerve stimulation decreases risk of local anesthetic systemic toxicity and the incidence and intensity of phrenic nerve disruption [15]. Using a high-frequency ultrasound probe , the structures that need to be identified are the carotid artery, the internal jugular vein, the SCM, the anterior and middle scalene muscles and the brachial plexus in the interscalene groove. The plexus at this level is hyperechoic and the block is performed by placing local anesthetic within the fascia and avoiding an intra-fascicular injection into the nerve roots of the plexus (Fig. 5.2). An interscalene block will reliably block nerve fibers originating from C5 to C7. Because of the distribution of this block, there is often sparing of the ulnar nerve, which is why this block is not used for procedures below the elbow. With this block, there is a real risk of hemidiaphragmatic paresis, which can be nearly 100% when traditionally performed [16]. The degree of hemiparesis can be decreased by using lower volumes of local anesthetic, and using ultrasound the volume of local anesthetic should be based on visual spread, not a particular pre-set volume [17]. Patients may have some respiratory compensation by having increased contralateral diaphragm movement. Despite the ability of some patients to compensate, it is paramount to try to decrease phrenic nerve disruption as we are encountering an increased number of elderly patients with baseline respiratory dysfunction. Ultrasound-guided interscalene block with extrafascial injection can reduce the incidence of respiratory disruption with similar analgesia to conventional injection techniques [15]. While injecting in an extrafascial plane did reduce phrenic nerve disruption it did increase the time to onset of block and decreased duration.

In addition to providing immediate pain relief for a period of hours during the duration of the local anesthetic, prolonged anesthesia/analgesia can be supplied by a nerve catheter. Through this nerve catheter, either SCP or interscalene, local anesthetic can be delivered in a continuous infusion from a pump for a period of days for pain relief. Ambulatory interscalene nerve catheter infusions have been proven to be effective, convenient and safe [18]. Not all locations are able to provide the necessary infrastructure or trained personnel to manage ambulatory catheters. In addition to having a clinical framework in place, it is vital that there is appropriate patient selection to ensure a safe, effective implementation of an outpatient nerve catheter service [19].

Historically, opioids have been the sole method for pain control. Opioid-based analgesic therapy has many side effects, and limiting these side effects is one of the main objectives of multimodal analgesia (MMA). Clinical pathways that include MMA have been shown to effectively improve length of stay, post-operative complications, discharge to home and hospital cost [20]. In addition to nerve blocks to aid in pain control, a multimodal analgesia approach is thus recommended. The key to any MMA program is through the use of drugs from different drug classes. Classes most commonly used are opioid (morphine, hydromorphone, and oxycodone), non-steroidals (ibuprofen and COX2-inhibitors), acetaminophen, ketamine, alpha-2 agonists (dexmedetomidine and clonidine) and anti-epileptics (pregabalin, gabapentin).

Sensory innervation of the clavicle remains controversial and thus creates a dilemma when attempting to provide regional anesthesia. Also complicating current understanding of the innervation of the clavicle is the lack of comparative studies evaluating the different types of fractures that can occur and the corresponding distribution of pain. The innervation of the medial portion of the clavicle is ostensibly different than that of the lateral portion. In short, more research is definitely needed, but until a definitive answer has been reached, we are left with choices with little evidentiary support. There are two situations that can be addressed in the near term from strong practical and anatomic standpoint. The first situation to be addressed is analgesia that needs to be provided in the emergency department for pain from a clavicle fracture. The nerve block most appropriate for this setting is the SCP block; it is fairly easy to learn, avoids phrenic nerve paralysis and can be performed quite quickly with good pain relief [12]. Nerve blocks have also been shown to decrease length of stay compared with procedural sedation for upper extremity fractures in the emergency department [21]. The second situation is in the perioperative arena. This location has numerous advantages including time to perform multiple procedures, regional anesthesiologists and a block team to perform more complex nerve blocks. To completely block all of the anatomically understood pain fibers for clavicular surgery, an ISB combined with an SCP block can be performed. Combining these two blocks may be complex and time-consuming but has been demonstrated to provide complete surgical anesthesia for clavicular fracture [22].

A 74-year-old female was evaluated in the emergency department for hip pain after a motor vehicle accident. A physician anesthesiologist arrived to evaluate the patient for placement of a femoral nerve catheter per institutional hip fracture protocol. After placement of the femoral nerve catheter and deposition of local anesthetic for immediate pain control the patient noted pain relief in her hip. Upon resolution of her hip pain the patient immediately complained of 8/10 pain in her ipsilateral shoulder. It was noted that she had bruising consistent with a seatbelt, but a chest X-ray and physical exam did not appreciate any sign of pneumothorax. After discussion with the orthopedic trauma team, an X-ray was also taken of the shoulder, which showed a mid-clavicle fracture.