by Kim, John Y. S.; Qiu,
Cecil S.; Chiu, Wen-Kuan; Feld, Lauren N.; Mioton, Lauren M.; Kearney, Aaron;
Fracol, Megan
Background: Animation deformity is characterized by implant deformity with
pectoralis contraction after subpectoral implant-based breast reconstruction.
Extant methods to measure and analyze animation deformity are hampered by the
paucity of objective, quantitative data. The authors endeavored to supplement
subjective measures with an in-depth quantitative analysis.
Methods: Patients undergoing subpectoral implant-based breast reconstruction
were followed prospectively with video analysis of animation deformity. Nipple
displacement and surface area of contour deformity in resting and contracted
states were quantified using imaging software. Degree of animation was compared
to breast size, body mass index, division of pectoralis muscle, complications,
and radiation therapy.
Results: One hundred forty-five reconstructed breasts (88 patients) were
analyzed. Mean nipple displacement was 2.12 ± 1.04 cm, mean vector of nipple
displacement was 62.5 ± 20.6 degrees, and mean area of skin contour
irregularity was 16.4 ± 15.41 percent. Intraoperative pectoralis division,
smooth/round implants, and bilateral reconstructions were associated with
greater deformity. A three-tiered grading system based on thresholds of 2-cm
net nipple displacement and 25 percent skin contour irregularity placed 41.4
percent of breasts in grade 1, 35.9 percent in grade 2, and 22.8 percent in
grade 3. Interrater variability testing demonstrated 89.5 percent overall
agreement (kappa = 0.84).
Conclusions: This study presents the first quantitative
analysis of animation deformity in prosthetic breast reconstruction. Geometric
analysis of nipple displacement vector and increasing animation with pectoralis
division both implicate the inferior pectoralis myotome as a primary driver of
animation deformity. A concomitant grading schema was developed to provide a
standardized framework for discussing animation from patient to patient and
from study to study.
