The Achilles heel of skin-sparing mastectomy is the high rate of skin necrosis, as perfusion of long random skin flaps depends on the thin layer of subcutaneous tissue. Although some studies have evaluated several risk factors, the findings have been contradictory, and no established patient selection criteria have yet emerged.1
We read with interest the article by Kobraei et al.2 and would like to comment on it. They performed a retrospective evaluation of 102 patients who underwent 155 skin-sparing mastectomies with immediate prosthetic reconstruction to identify risk factors for adverse outcomes.
Their surgical approach to skin-sparing mastectomy was variable and included mainly periareolar incisions, typically applied to women with A/B cup breasts; however, patients included in their study were overweight (mean body mass index, 27 kg/m2; range, 16.5 to 48.5 kg/m2) and were more likely to have hypertrophic breasts larger than B cup.
The use of the Wise-pattern skin-sparing mastectomy in hypertrophic breasts3 not only reduces the risk of ischemic complications by shortening random skin flaps and avoiding excess skin, but also standardizes random flap length, which is necessary for material homogeneity of the study. The authors do not report the breast sizes in their material and do not explain why they ignore Wise-pattern skin-sparing mastectomy in large-breasted patients, thus reducing the significance of their results.
Skin-sparing mastectomy is based on breast fascial anatomy, requiring meticulous surgical technique and gentle tissue handling to prevent skin necrosis.4 Although the authors can be criticized for variability resulting from involvement of seven different surgeons, they preferred not to establish surgical experience as a potential procedure-related risk factor. We believe that a standardized procedure from a single experienced surgeon is crucial for reliable data, particularly from a small sample.
Moreover, it is essential to use a sound methodology when applying multivariate analysis techniques, and larger samples are better than smaller ones, as they tend to minimize error rates and maximize generalizability for the population of interest. Their statistical model showed that radiotherapy was significantly related to implant loss, thus suggesting, on the basis of this result, that prosthetic reconstruction be avoided in previously irradiated breasts. Nevertheless, the major statistical limitation was that this series experienced only 14 adverse outcomes (implant loss). The authors completely disregarded the 10:1 rule that mandates at least 10 outcomes for each predictor.5 Although in our daily practice skin-sparing mastectomy in women who have previously undergone irradiation is usually contraindicated, we cannot avoid pointing out that such a conclusion potentially represents a typical statistical type I error (false-positive), which may lead to unnecessary treatment or wrong patient exclusion from therapeutic indication. Unfortunately, we also lack information on whether a power analysis was performed for this study or not.
We appreciate the authors’ efforts, but we feel their study design has several critical flaws regarding methodology, and results from their analysis could be influenced by these limitations. Studies aiming to investigate risk factors for complications should be conducted with a homogeneous population, consider a specific surgical procedure, and apply rigorous statistical analyses, to effectively contribute in helping both patients and surgeons choose better options.
The authors have no financial interest to declare in relation to the content of this communication.
Benedetto Longo, M.D.
Fabio Santanelli, M.D. Ph.D.
“Sapienza” University of Rome
School of Medicine and Psychology
Plastic Surgery Unit
1. Woerdeman LA, Hage JJ, Hofland MM, Rutgers EJ. A prospective assessment of surgical risk factors in 400 cases of skin-sparing mastectomy and immediate breast reconstruction with implants to establish selection criteria. Plast Reconstr Surg. 2007;119:455–463
2. Kobraei EM, Nimtz J, Wong L. Risk factors for adverse outcome following skin-sparing mastectomy and immediate prosthetic reconstruction. Plast Reconstr Surg.. 2012;129:234e–241e
3. Losken A, Collins BA, Carlson GW. Dual-plane prosthetic reconstruction using the modified Wise pattern mastectomy and fasciocutaneous flap in women with macromastia. Plast Reconstr Surg. 2010;126:731–738
4. Carlson GW. Skin sparing mastectomy: Anatomic and technical considerations. Am Surg. 1996;62:151–155
5. Steyerberg EW, Eijkemans MJ, Harrell FE Jr, Habbema JD. Prognostic modeling with logistic regression analysis: A comparison of selection and estimation methods in small data sets. Stat Med.. 2000;19:1059–1079