Post-hoc power calculations to determine whether there was sufficient power to test for statistically significant differences between IA or SSISB/IA and CISB were performed.
The median total opioid/tramadol consumption (in IV mg equivalents of morphine) from admission to PACU until discharge from hospital was 5 mg in the CISB group and 10 mg for both the SSISB/IA and IA groups (P <0.003, Table 3).
The proportion of subjects requiring more than one antiemetic during the same period was 1.9% in the CISB group, 16.4% for the SSISB/IA group and 36.1% for the IA group (P <0.0001, Table 4).
The most commonly used block needles were the Stimuplex (B Braun, Bethlehem, PA, USA) for SSISB/IA and the Contiplex Tuohy (B Braun, Bethlehem, PA, USA) for CISB. Intermittent intra-articular local anaesthetic infiltration was administered with the Pain Care 2000 (BREG Inc, Vista, CA, USA) while CISB was provided by way of the PainBuster elastomeric device (Surgical Synergies, Auckland, NZ).
This retrospective analysis shows that for patients undergoing rotator cuff repair in a multi-provider private practice setting, CISB is associated with a reduction in total opioid/tramadol and antiemetic use during the first 24 postoperative hours.
Minimisation of postoperative pain and opioid consumption in patients receiving CISB is likely to provide benefits beyond the immediate postoperative period.
Additional cost savings in suitable patients receiving CISB could also be made by day of surgery discharge (NZ$300 to NZ$500 per night) (6), as time to discharge readiness following major shoulder surgery has been previously shown to be reduced by this treatment (10).
Despite the support for CISB provided by this and previous studies, barriers exist to the further uptake of this technique by many anaesthetists.
There was, however, a reduction in antiemetic consumption in the CISB group during the hospitalisation period.
In summary, this retrospective analysis confirms that of three commonly employed analgesic techniques for rotator cuff surgery in a typical multi-provider setting, CISB is associated with the lowest requirement for supplemental opioid and tramadol during the first 24 postoperative hours.