Volumetric changes of the latissimus dorsi muscle after postoperative chemotherapy in cases of immediate breast reconstruction with an extended latissimus dorsi musculocutaneous flap and implant.

Background: This study aimed to evaluate the volume reduction of latissimus dorsi muscle in patients who underwent immediate breast reconstruction using extended latissimus dorsi musculocutaneous (eLDMC) flap with implant after skin/nipple sparing mastectomy (SSM/NSM) and postoperative chemotherapy (POCTx).

Methods: We retrospectively reviewed clinical records of 19 patients who underwent this surgery with POCTx, and checked chest computer tomography (CT) at 7-10 days after surgery and 6-14 months after the end of chemotherapy, from May 2015 to October 2016. The motor nerve to latissimus dorsi muscle was severed in all patient. One plastic surgeon intervened and the follow up period was at least 18 months. Author obtained the area of latissimus dorsi muscle using the Picture Archiving and Communication System (PACS) in the axial view of the chest CT and it was verified by the experienced radiologist. The statistical test was performed (P<0.05).

Results: There was statistically decrease in latissimus dorsi muscle volume after the end of POCTx, range from 51.5-77.5%, average volume decrease was 62%, compared with latissimus dorsi muscle volume of the CT taken 7-10 days postoperatively (P<0.05). After a minimum follow-up period of 18 months, 14 of the 19 cases were satisfactory for both the surgeon and the patient. In 4 patients, breast volume was symmetrical when wearing bra, but the outline of the 90 cc implant was unfavorable. One patient had a smaller size of reconstructed breast than the other.

Conclusions: The size of the implant should be determined considering that average latissimus dorsi muscle reduction is 62%. Especially, the size of the implant should be chosen carefully if latissimus dorsi muscle is thick or it occupies a large portion of the entire flap.