Changes in spine alignment and postural balance after breast cancer surgery: a rehabilitative point of view

Breast cancer is the most common malignant tumor in female patients in developed countries. Recent articles indicate that one-sided mastectomy or minor breast surgery to treat breast cancer can have deleterious effects on posture and the musculoskeletal system. The purpose of this study was to investigate the alterations post-breast cancer surgery of the spine alignment associated to the balance not reported by the noninvasive instrumentation. We enrolled 30 women who had undergone treatment for breast cancer (BG) and were on a waiting-list for rehabilitation treatment and a control group of 30 healthy volunteer women (CG), matched by age and body mass index. The stabilometry was performed using a force platform (Kistler Instruments, Winterthur, Switzerland) test during quiet standing with closed-eyes (EC) and open-eyes (EO), recording the position of the center of pressure (CoP) for 51.2 sec. The stabilogram or the time plot of the two coordinates, X and Y, of the CoP was obtained, which represent anteroposterior and midlateral balance. Spinal posture was measured using the Formetric-4D rasterstereographic system (DIERS, International GmbH, Schlangenbad, Germany), and thoracic kyphotic angle, lumbar lordotic angle, and surface trunk rotation were evaluated. Sixty participants were analyzed (CG:30; BG:30). For the spine rasterstereography a statistically significant difference was shown with regard to anterior-posterior flexion of the trunk major in BG; pelvic inclination and twist of half-pelvis decreased in BG; normalized lumbosacral inversion point decreased in BG; surface rotation major in BG; and lateral deviation major in BG. Compared with the values for the stabilometry test with EO and EC, a statistically significant difference was observed, respectively, for ellipse length (mm; p = 0.04) and ellipse area (mm2; p = 0.04) with EO and in ellipse area (mm2) with EC (p = 0.05), increased in BG for both conditions. No difference was shown for CoP velocity and oscillations between the groups. Breast cancer survivors after prostheses or tissue expanders for mastectomy showed a spine's misalignment present both on the sagittal plane, both on the coronal and frontal plane, increased in BG regard to anterior-posterior flexion of the trunk, surface rotation, and lateral deviation. It is associated with greater energy expenditure for the postural balance control increased in BG with a major ellipse area in EO and EC conditions and major ellipse length in EC condition.