Table 1. Comparison of Supraclavicular Versus Infraclavicular Approaches.

Reference number	Groups Studied and Intervention	Results and Findings	Conclusions
Bharti et al. ( 53 )	Randomized, observer-blinded study of 60 patients split into 3 groups comparing ease of performance and surgical efficacy of USG nerve block approaches. Assessed block efficiency time, success rate, duration of block and post-op pain relief and block performance time of the different approaches.	Three groups were supraclavicular (SC), infraclavicular (IC), and interscalene (IS). Onset time was longer with IS group. No differences in imaging time/block performance. Pain scores/success rates and post-op analgesia were same. Two patients in IS group developed phrenic nerve palsy.	IS block below C6 nerve root has longer onset time than SC and IC approach, and has unsuitable cases of phrenic nerve palsy. Thus, other two approaches are preferred.
Arcand et al. ( 62 )	Randomized prospective study of 80 patients split into two groups examining USG SC and IC blocks. Hypothesized that performance time and quality of IC approach is similar to SC.	Sensory and motor block, and supplementation rate assessed. Only significant difference was supplementation rate for radial nerve distribution, where IC group had 18% supplementation rate and 0% in SC. Performance times were not significantly different and technique pain scores were same.	USG IC block is at least as rapidly performed as SC approach and produces similar degree of surgical anesthesia without supplementation.
De José María et al. ( 56 )	Randomized trial that compared success rate, complications, and performance time of USG SC vs IC brachial plexus block in 80 children 5-15 divided into two groups. Block duration and volumes were measured.	IC group 88% achieved surgical anesthesia without supplemental analgesia compared to 85% in SC group. Failures in group IC were due to arterial puncture and suboptimal radial sensory block. Failure in SC group were due to suboptimal ulnar sensory block. IC group performance time was 13 min avg and SC was 9 min (significantly different).	Both approaches are effective in children and safe. No major complications were noted. The SC approach was faster to perform.
Koscielniak-Nielsen et al. ( 64 )	Randomized study of 120 patients divided into two groups comparing USG SC vs. IC block performance and onset times, efficacy, and complications. Hypothesized SC approach to be effective and overall better since it is more superficial and easier to visualize with US.	Sensory scores of seven terminal nerves were assessed every 10 minutes until block was achieved and deemed effective for surgery. Significantly more patients in IC group were ready in 20-30 min with a block performance time of 5.7 min versus S group 5.0 min. Block efficacy greater in IC group than SC (93% vs 78%). SC group had superior block of axillary nerve but insignificant median and ulnar nerves block.	IC block has faster onset, better efficacy, and less adverse events than SC approach. Block time and patients’ acceptance of procedure were not significantly different.
Harrison et al. ( 59 )	RCT comparing efficacy of SC vs. IC perineural catheters for USG through-catheter bolus anesthesia. 50 patients randomly assigned to two groups (SC and IC). Primary measurement was time to achieve complete sensory block in ulnar and median distribution. The second measurement outcomes were procedure time, pain, side effects, post-op pain, and weakness.	All but 2 perineural catheters were placed successfully. 21/24 (88%) SC patients and 24/24 (100%) IC patients achieved complete sensory block by 30 minutes with no significant difference in time to achieve the complete anesthesia. SC group showed more post-op sleep disturbances.	Both SC and IC perineural catheters using a through-catheter bolus of anesthesia provided effective block with no true significant difference between the two approaches. They are both effective in achieving brachial plexus anesthesia.
Mariano et al. ( 61 )	RCT of 60 patients comparing efficacy of IC vs SC continuous peripheral nerve blocks for post-op analgesia. Split 31 (IC) and 29 (SC), pre-op patients received brachial plexus blocks via USG IC or SC catheter technique. Post-op, subjects discharged with anesthetic pumps with primary outcome measured as average pain score on day after surgical procedure.	Subjects in IC group showed average pain median of 2. SC group reported median of 4.0 (10th – 90th percentiles 0.6-7.7). Additionally, post-op day 1 scores were lower in the IC group relative to the SC group with least pain scores being 0.5 vs. 2.0, respectively. IC group also required less supplemental oral analgesia.	IC perineural catheter approach provides more effective analgesia compared to the SC approach.
Tran et al. ( 54 )	Prospective, observer-blinded RCT that compared USG SC, IC, and axillary blocks of the brachial plexus in UE surgery. 120 patients evenly divided into SC, IC, and axillary groups. Assessed block performance time, pain scores, success rate, and complications. Main consequence was total anesthesia time – defined as sum between procedure performance and onset times.	No statistically significant differences noted in total anesthesia time, success rate, pain scores, paresthesia, or vascular complications. The axillary group required higher number of total needles passes relative to other two approaches along with longer overall performance time. SC blocks resulted in increased rate of Horner syndrome.	USG brachial plexus blocks using SC, IC, and axillary approaches had similar success rates. However, axillary approach takes longer and requires more needle passes. SC approach results in higher incidence of Horner syndrome as a complication.
Fredrickson et al. ( 65 )	Prospective, observer blinded RCT of 60 patients comparing onset time of anesthesia in brachial plexus blocks. SC approach was injected into ‘corner pocket’ inferolateral/lateral to subclavian artery. IC approach was a triple point injection placed all sides of axillary artery. Assessed onset time of block and need for supplementation.	Mean onset time in of blockade in all distributions was determined to be similar in both groups, with SC approach being 22 min and IC group 21 min. Complete sensory blockade was fully achieved in 57% of SC group and 70% of IC group both by 30 min. 11 failures occurred with SC approach due to incomplete ulnar blockade.	Onset of block times is similar in both approaches; however surgical anesthesia was more optimal in IC group due to more complete block of the ulnar distribution compared to SC.
Yazer et al. ( 57 )	Prospective RCT comparing USG intracluster injection using SC approach vs. IC approach of the brachial plexus. 64 patients randomly divided into two groups using same anesthetic agent (lidocaine 1.5% w/epi). Performance time, rate of needle passes, pain during procedure, and side effects were assessed. Main outcome was total anesthesia time.	No differences were observed in success rate, block-related pain scores, or complications such as abnormal paresthesia or vascular punctures. The total anesthesia-related time was shorter in the SC group (8.9 min vs. 17.6) due to more rapid onset. IC group required less needle passes (2 vs. 6) and shorter performance time. There was also a decreased incidence of Horner syndrome as a complication in the IC group.	Both approaches have a comparable success rate. SC approach results in shorter total-anesthesia related time due to more rapid onset. However, SC approach has much higher incidence of Horner syndrome.
Gauss et al. ( 55 )	Prospective observational study on risk of PTX in USG periclavicular brachial plexus nerve blocks. 2963 IC approach blocks, and 3403 SC blocks were performed under US guidance.	PTX occurred in four cases, two in the IC group and two in the SC group. All cases relieved via chest tube. PTX risk is reduced compared to reported incidence when not using US monitoring (up to 6.1% vs. 0.06% in this study). Additionally, all PTX cases were performed by anesthesiologists who performed fewer than 20 blocks previously.	Feared complication of brachial plexus nerve blocks includes pneumothorax given anatomic proximity of the pleura. US-guidance significantly reduces risk.
Dhir et al. ( 60 )	Prospective, observer-blinded RCT comparing efficacy of SC and IC block approaches for elbow surgery. Ropivacaine USG brachial plexus blocks given to 150 patients divided into 2 groups for SC and IC block. Assessed performance and sensory block onset time. Also, surgical anesthesia, procedural pain, motor block, axillary block, and ulnar sparing were assessed.	Similar mean block procedure time in both groups – 285 (+/- 128) seconds in IC and 307 (+/- 138) seconds in SC. Sensory block onset in both groups was similar.	Both blocks equally effective for surgical elbow procedures. Block onset time, procedure time, and failure rate were similar in both groups. Lower incidence of paresthesia in IC group.
Park et al. ( 58 )	Systematic review assessing RCTs that assessed SC vs IC brachial plexus block of 4 peripheral branches. Primary outcome was incidences of incomplete sensory block. Secondary outcomes were successful blockade incidence, performance time, duration of analgesia, complications, and onset time of block. 10 RCTs with 676 patients were assessed.	Partial block at 30 minutes in radial nerve distribution was greater in the IC group, which favored SC group in this case. However, the reverse was true in the ulnar distribution (IC had lower incidence). No differences in secondary outcomes were really noted. Complications of paresthesia, injection pain, phrenic nerve palsy, and Horner’s was notably more in SC group.	IC approach demonstrates higher rates of incomplete block in radial distribution, but lower incidence than SC in ulnar distribution – particularly with multiple injection technique. Similar outcomes in successful overall block rate, time, and onset. More complications in SC approach.
Altinay et al. ( 63 )	Retrospective review of data on pediatric patients who underwent USG brachial plexus blocks between 2015-2017. 24 total patients, 15 underwent SCB approach and 9 in the ICB approach. Mean age of 9.6 years.	Mean duration of 9.54 minutes for SC block and 12.9 minutes for IC block. Mean block time was similar in both SCB and ICB, 7.5 hours vs. 7.4 hours, respectively. No complications.	Both approaches safe and effective in pediatric population.