Our study demonstrated that the new orthosis significantly reduced pain, breast displacement and mechanical pressures in women with natural and augmented breast tissue when undergoing activities in prone position. Greatest comfort and complete pain relief was observed with the largest size-3 orthosis in our group of women with B-F cup-sizes. The orthosis allowed peak pressure to be lowered by up to 85%, maximum force by up to 96%, and medio-lateral displacement of breast tissue by up to 16%, which in turn resulted in up to 51% increase of breast tissue in the antero-posterior plane.
Natural breast tissue demonstrated a greater proportional protection from displacement and deformation with the orthosis compared to augmented individuals. This can be attributed to the implant’s fixed volume and inability to simulate natural human tissue movement.
The findings of this larger study are in line with our earlier pilot study . Here we provide additional data on bilateral measurements and a variety of densities of the orthosis.
Our findings are clinically important to provide lactating women or women with natural painful breast tissue a safer and more comfortable option when undergoing prone activities, such as massage to relief back pain. Additionally, use of the orthosis in women with augmented breast tissue may reduce the risk of rupture or displacement of implant material during activities involving external pressure and mechanical loading of the breast tissues, often involved in massage, chiropractic, osteopathic, and physical therapy modalities .
Stiffness, fluidity, elasticity and density vary between tissue and implant material, causing shear strains parallel to the patient’s plane of contact, and when reaching the limits of elasticity the implant material or human tissue may rupture or tear. Patients who have undergone breast reconstruction using implants after breast cancer surgery are likely to have a higher failure rate than primary augmentation patients, as their residual natural tissues are generally more vulnerable . Furthermore, as implant material has no neural innervation the individual may be unaware of the damage, known as silent rupture. Conversely, when human tissue fails and the implant moves, asymmetry such as a symmastia or ‘uni-breast’ is caused .
The newly developed orthosis’ structure allows for specificity in load distribution, isolating pressure tolerant areas and relieving sensitive areas (Figure 1a). Further research is needed to capture the breast pain in relation to device density and duration of prone loading. In our study, patients were most comfortable lying prone on the size-3 firm orthosis during the 1 hour testing sessions. Our subgroup study suggests that the softer density device provides less loading protection, but additional studies are needed to ascertain whether softer varieties provide greater rib cage comfort when used for longer periods. In practice lighter subjects generally prefer the softer density device whilst heavier subjects prefer the firmer density device. Comfort and correct fit are key to the orthosis being superior to current methods of using towels, pillows and bolsters. The orthosis is reliable in its capacity, its use is repeatable and results are reproducible, which is important in litigious environments.
Professional fitting by an orthotist or primary healthcare practitioner is recommended to ensure appropriate use and maximum protection (Additional file 1). It is imperative that the altered and ‘at risk’ breast structures be exposed to minimal loading and therefore must be adjacent to the device. The orthosis should be part of ongoing management when breast tissue has been altered. It is advisable that patient have their own orthosis for use in day to day management.
Future research could test the orthosis in situations other than prone, for example in the upright positioning such as car seat travel to reduce the risk of breast implant rupture by the seat belt during an accident . A light harness or fixation system could hold the orthosis in position against the torso. Further larger long-term studies are needed to determine potential risk reduction in complication rates and breast implant longevity with regular use of the orthosis.