Diaphragm‐sparing effect of the infraclavicular subomohyoid block vs low volume interscalene block. A randomized blinded study

Abstract

Shoulder surgery is the second most common orthopedic procedure. 1 It usually results in intense postoperative pain, the control of which may require the use of large doses of opioids. 2 Interscalene block is the standard block for shoulder surgery. It blocks the brachial plexus (BP) thereby providing adequate postoperative analgesia and improving the rehabilitation. However, it results in phrenic nerve block (PrNB) and hemi-diaphragmatic paresis which impairs the respiratory mechanics markedly. 3-8 Unfortunately, patients with limited respiratory reserve, who are at utmost need to bypass opioid-induced respiratory depression, may also not tolerate the PrNB-associated with interscalene block. 2 To preserve the respiratory function in these patients, it was suggested to use either a modified interscalene block or a distal BP block of either cords or branches. [4][5][6][7][8][9] Low volume interscalene block (LVSB), using 5 mL, was reported to provide adequate shoulder analgesia and decrease the PrNB incidence by 50% as compared with a standard block using 20 mL. 4-6 ISO (infraclavicular-subomohyoid) block, a recent single

Diaphragm-sparing nerve blocks for shoulder surgery, revisited

“…Since January 2017, 16 RCTs have investigated diaphragm-sparing nerve blocks for shoulder surgery14–29 (see online supplementary table 1 and figure 1). Overall, the quality of the trials was high (median Jadad score=3.5).…”

“…Beside supraclavicular blocks, recent trials have also investigated costoclavicular blocks,25 anterior suprascapular nerve blocks,16 20 29 upper trunk blocks,28 combined infraclavicular brachial plexus blocks-suprascapular nerve blocks,23 24 and combined axillary-posterior suprascapular nerve blocks26 27 as alternatives to ISB. While combined infraclavicular-suprascapular blocks efficiently target the cords of the brachial plexus as well as the suprascapular nerve, HDP may not be entirely circumvented with a reported incidence of 6% 24. Moreover, analgesia may be inferior to ISB during the initial (0.5 hour) postoperative period 23.…”

“…The infraclavicular approach targets the brachial plexus at the cord level thus anesthetizing the lateral pectoral nerve (lateral cord), subscapular nerve (posterior cord), and axillary nerve (posterior cord) while the selective suprascapular nerve block anesthetizes the remaining nerve supplying the shoulder joint. The infraclavicular approach also offers operators considerable practical flexibility, as it can be performed using paracoracoid23 or retroclavicular24 50 techniques. Moreover, the infraclavicular approach can target the three cords en bloc23 or select out the lateral and posterior cords 51.…”

“…Moreover, the infraclavicular approach can target the three cords en bloc23 or select out the lateral and posterior cords 51. In turn, the suprascapular nerve block can performed using either with an anterior24 or posterior23 approach.…”

“…To date, two RCTs have compared ISB with combined infraclavicular-suprascapular block 23 24. In the first trial, Aliste et al 23 found that, despite a 0%-incidence of HDP, combined infraclavicular-posterior suprascapular blocks result in higher pain scores than ISB during the initial (0.5 hour) postoperative period 23.…”