BACKGROUND: Postoperative pain management after total shoulder arthroplasty (TSA) can be challenging. Given the variety of pain management options available, the purpose of this investigation was to systematically review the literature for randomized controlled trials reporting on pain control after shoulder arthroplasty. We sought to determine which modalities are most effective in managing postoperative pain and reducing postoperative opioid use.
METHODS: A systematic review was performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. PubMed, Scopus, and the Cochrane Central Register of Controlled Trials were searched for Level I-II randomized controlled trials that compared interventions for postoperative pain control after TSA. Pain control measures included nerve blocks and nerve block adjuncts, local injections, patient-controlled analgesia, oral medications, and other modalities. The 2 primary outcome measures were pain level measured on a 0-10 visual analog scale and opioid use. The risk of study bias and methodologic quality were analyzed using The Cochrane Collaboration\'s Risk of Bias 2 (RoB 2) tool. Network meta-analyses were performed for visual analog scale pain scores at postsurgical time points and opioid use using a frequentist approach and random-effects model, with heterogeneity quantified using the I2 statistic. Treatments were ranked using the P score, and statistical significance was set at P < .05.
RESULTS: The initial search yielded 2391 articles (695 duplicates, 1696 screened, 53 undergoing full-text review). Eighteen articles (1358 shoulders; 51% female patients; mean age range, 65-73.7 years; 4 studies with low risk of bias, 12 with some risk, and 2 with high risk) were included and analyzed. At 4 and 8 hours postoperatively, patients receiving local liposomal bupivacaine (LB) injection (P < .001 for 4 and 8 hours) or local ropivacaine injection (P < .001 for 4 hours and P = .019 for 8 hours) had significantly more pain compared with patients who received either a continuous interscalene block (cISB) or single-shot interscalene block (ssISB). No differences in opioid use (at P < .05) were detected between modalities. The P scores of treatments demonstrated that ssISBs were most favorable at time points < 24 hours, whereas pain at 24 and 48 hours after surgery was best managed with cISBs or a combination of an ssISB with a local LB injection.
CONCLUSIONS: Interscalene blocks are superior to local injections alone at managing pain after TSA. Single-shot interscalene blocks are optimal for reducing early postoperative pain (< 24 hours), whereas pain at 24-48 hours after surgery may be best managed with cISBs or a combination of an ssISB with a local LB injection.

BACKGROUND: Dexmedetomidine has been proposed as a perineural local anaesthetic (LA) adjunct to prolong peripheral nerve block duration; however, results from our previous meta-analysis in the setting of brachial plexus block (BPB) did not support its use. Many additional randomized trials have since been published. We thus conducted an updated meta-analysis.
METHODS: Randomized trials investigating the addition of dexmedetomidine to LA compared with LA alone (Control) in BPB for upper extremity surgery were sought. Sensory and motor block duration, onset times, duration of analgesia, analgesic consumption, pain severity, patient satisfaction, and dexmedetomidine-related side-effects were analysed using random-effects modeling. We used ratio-of-means (lower confidence interval [point estimate]) for continuous outcomes.
RESULTS: We identified 32 trials (2007 patients), and found that dexmedetomidine prolonged sensory block (at least 57%, P < 0.0001), motor block (at least 58%, P < 0.0001), and analgesia (at least 63%, P < 0.0001) duration. Dexmedetomidine expedited onset for both sensory (at least 40%, P < 0.0001) and motor (at least 39%, P < 0.0001) blocks. Dexmedetomidine also reduced postoperative oral morphine consumption by 10.2mg [-15.3, -5.2] (P < 0.0001), improved pain control, and enhanced satisfaction. In contrast, dexmedetomidine increased odds of bradycardia (3.3 [0.8, 13.5](P = 0.0002)), and hypotension (5.4 [2.7, 11.0] (P < 0.0001)). A 50-60µg dexmedetomidine dose maximized sensory block duration while minimizing haemodynamic side-effects. No patients experienced any neurologic sequelae. Evidence quality for sensory block was high according to the GRADE system.
CONCLUSIONS: New evidence now indicates that perineural dexmedetomidine improves BPB onset, quality, and analgesia. However, these benefits should be weighed against increased risks of motor block prolongation and transient bradycardia and hypotension.

The trend towards regional anesthesia began in the late 1800s when William Halsted and Richard Hall experimented with cocaine as a local anesthetic for upper and lower limb procedures. Regional anesthesia of the upper limb can be achieved by blocking the brachial plexus at varying stages along the course of the trunks, divisions, cords and terminal branches. The four most common techniques used in the clinical setting are the interscalene block, the supraclavicular block, the infraclavicular block, and the axillary block. Each approach has its own unique set of advantages and indications for use. The supraclavicular block is most effective for anesthesia of the mid-humerus and below. Infraclavicular blocks are useful for procedures requiring continuous anesthesia. Axillary blocks provide effective anesthesia distal to the elbow, and interscalene blocks are best suited for the shoulder and proximal upper limb. The two most common methods for localizing the appropriate nerves for brachial plexus blocks are nerve stimulation and ultrasound guidance. Recent literature on brachial plexus blocks has largely focused on these two techniques to determine which method has greater efficacy. Ultrasound guidance has allowed the operator to visualize the needle position within the musculature and has proven especially useful in patients with anatomical variations. The aim of this study is to provide a review of the literature on the different approaches to brachial plexus blocks, including the indications, techniques, and relevant anatomical variations associated with the nerves involved.