Reply: Comparison of Outcomes with Tissue Expander, Immediate Implant, and Autologous Breast Reconstruction in Greater Than 1000 Nipple-Sparing Mastectomies
In our study, overall mastectomy flap necrosis rates were a combination of minor and major mastectomy flap necrosis, defined as necrosis requiring only local wound care and necrosis requiring débridement, respectively. Although overall mastectomy flap necrosis rates were relatively high (tissue expander, 9.6 percent; immediate implant, 19.4 percent; and autologous, 14.4 percent), the majority of these cases involved only minor necrosis. Rates of minor necrosis were 7.7 percent (tissue expanders), 12.9 percent (immediate implant), and 9.2 percent (autologous), which also included cases of superficial epidermolysis. Major mastectomy flap necrosis requiring any form of débridement (in the office or the operating room) occurred in 1.9 percent of tissue expander, 6.5 percent of immediate implant, and 5.3 percent of autologous cases, which corresponds well with rates reported in the literature.1–4
In the tissue expander cohort, major mastectomy flap necrosis occurred after therapeutic mastectomy in 1.0 percent of cases and after prophylactic mastectomy in 0.9 percent of cases. In the immediate implant cohort, 2.7 percent were therapeutic and 3.8 percent were prophylactic; and in the autologous cohort, 1.5 percent were therapeutic and 3.8 percent were prophylactic. Major infection occurred in 1.1 percent of tissue expander cases (therapeutic, 0.8 percent; prophylactic, 0.3 percent), 1.7 percent of immediate implant cases (therapeutic, 0.7 percent; prophylactic, 1.0 percent), and 0.8 percent of autologous reconstruction cases (therapeutic, 0 percent; prophylactic, 0.8 percent). Furthermore, mastectomy indication (therapeutic versus prophylactic) was not identified as a risk factor for complications on logistic regression analysis.
Autologous reconstruction, similar to immediate implant reconstruction, had significantly increased rates of mastectomy flap necrosis compared with two-stage reconstruction. Although autologous flap reconstruction provides vascularized tissue under mastectomy flaps, there is less control over the volume placed under skin flaps compared with tissue expander reconstruction. A large flap, similar to a large implant, places increased stress on mastectomy flaps, and can subsequently compromise perfusion and cause ischemia of the skin envelope. Although many factors may be responsible, the increased initial stress on mastectomy flaps secondary to flap size likely contributed to the increased rates of mastectomy flap necrosis in this reconstructive cohort.
Although intraoperative indocyanine green angiography can often predict ischemia of mastectomy flaps,5 this technology has been shown to be most useful when used selectively in high-risk patients.6 Furthermore, when deciding on the utility of intraoperative imaging, the severity and implications of these complications must be taken into consideration, particularly in the context of the type of reconstruction. Although the rate of mastectomy flap necrosis was higher in autologous reconstruction, the risk for reconstructive failure secondary to major mastectomy flap necrosis is lower with this technique compared with implant-based reconstruction, given the presence of vascularized tissue under the skin flaps. The surgeon must take into consideration the patient’s risk factors, the ablative surgery, and the implications of ischemic complications when making intraoperative decisions. Furthermore, we typically inject a dilute epinephrine-containing solution into the breast before mastectomy. Although this precludes use of intraoperative angiography, we have found it helpful for breast surgeons in maximizing visualization for precise flap dissection.
As described in our study, one of the most important variables when examining outcomes with nipple-sparing mastectomy is mastectomy flap quality, which is also one of the more difficult variables to quantify.