Table 1

Current state of knowledge and areas requiring future investigation

Diaphragm-sparing blockCurrent state of knowledgeFuture investigation regarding postoperative analgesia for shoulder surgeryFuture investigation regarding surgical anesthesia for shoulder surgery
ISBNo current permutation of ISB can achieve a 0%-rate of HDPCan a multimodal intervention (eg, US-guided ISB with small LA volume and dilute LA concentration and extrafascial LA injection) provide postoperative analgesia and a 0%-incidence of HDP?Can a multimodal intervention (eg, US-guided ISB with small LA volume and dilute LA concentration and extrafascial LA injection) provide surgical anesthesia and a 0%-incidence of HDP?
SCBSCB with LA injection inside the neural cluster cannot achieve a 0%-rate of HDP
SCB with LA injection (20 mL levobupivacaine 0.5%-epinephrine 5 µg/mL) posterolateral to the brachial plexus provides similar analgesia to ISB with a 9%-rate of HDP
Can LA injection posterolateral to the brachial plexus with a volume <20 mL provide similar analgesia to ISB and a 0%-incidence of HDP?Can LA injection posterolateral to the brachial plexus with a volume <20 mL provide surgical anesthesia and a 0%-incidence of HDP?
UTBUTB (15 mL bupivacaine 0.5%) achieves surgical anesthesia and provides similar postoperative analgesia to ISB with a 5%-rate of HDPCan a volume <15 mL provide similar analgesia to ISB and a 0%-incidence of HDP?Can a volume <15 mL provide surgical anesthesia and a 0%-incidence of HDP?
Anterior SSNBAnterior SSNB (10–15 mL LA) provides similar analgesia to ISB
(rate of HDP not assessed)
In cadavers: 5–10 mL injectate spreads to the phrenic nerve in 20% of cases
Will anterior SSNB (10–15 mL LA) result in HDP?
Can anterior SSNB (with a volume <5 mL) provide similar analgesia to ISB and a 0%-incidence of HDP?
Can anterior SSNB (with a volume <5 mL) provide surgical anesthesia and a 0%-incidence of HDP?
CCBCCB (20 mL levobupivacaine 0.5%- epinephrine 5 µg/mL) provides similar analgesia to ISB with a 0%-rate of HDPCan the 0%-rate of HDP be reproduced in future confirmatory trials?Can CCB provide surgical anesthesia?
Combined ICB and SSNBICB (20 mL levobupivacaine 0.25%- epinephrine 5 µg/mL) and posterior SSNB (10 mL levobupivacaine 0.25%-epinephrine 5 µg/mL) achieves a 0%-rate of HDP but analgesia is inferior to ISB during the first 30 min
ICB (20 mL ropivacaine 0.5%) and anterior SSNB (5 mL ropivacaine 0.5%) provides similar analgesia to ISB with a 6%-rate of HDP
Can ICB (with a volume <20 mL) and anterior SSNB (with a volume <5 mL) provide similar analgesia to ISB and a 0%-incidence of HDP?Can ICB (with a volume <20 mL) and anterior SSNB (with a volume <5 mL) provide surgical anesthesia and a 0%-incidence of HDP?
  • CCB, costoclavicular brachial plexus block; HDP, hemidiaphragmatic paralysis; ICB, infraclavicular brachial plexus block; ISB, interscalene brachial plexus block; LA, local anesthetic; SCB, supraclavicular brachial plexus block; SSNB, suprascapular nerve block; US, ultrasonography; UTB, upper trunk block.