Background: The serratus anterior plane (SAP) block cannot block the most 
internal mammary region, whereas, the transversus thoracis plane (TTP) block 
can. Hence, we studied patients undergoing mastectomy to determine whether 
the combination of these two blocks provides better pain control than the 
serratus anterior plane block alone.
Methods: Fifty-four adult female patients scheduled for modified radical 
mastectomy were randomly allocated to one of two groups. Group (A) (n = 27) 
received the serratus anterior plane block alone, and group (B) (n = 27) received 
the transversus thoracis plane block combined with the serratus anterior plane 
block. The primary outcome measure was post-operative opioid consumption. 
Secondary outcome measures were visual analogue scale (VAS), duration till 
request of the first analgesia, and total sum of intra-operative fentanyl 
consumption.
Results: the cumulative 24-hour postoperative opioid consumption, VAS score 
both at rest and movement, time of request of the first analgesia, and 
intraoperative fentanyl consumption showed no significant difference between 
the two groups. 
Conclusion: The combination of transversus thoracis plane block and serratus 
anterior plane block has no additional analgesic effect than serratus anterior 
plane block alone for the management of acute postmastectomy pain.
Clinical trial registration: registered at “www.clinicaltrial.gov" under number: 
(NCT04375111).