The ENIVO™ Study. Pilot Safety Assessment of the ENIVO™ System in Patients Undergoing Simple Unilateral Mastectomy

Product used for intervention: ENIVO™ System (‘ENIVO’) Patients undergoing simple mastectomy that would typically receive a surgical drain as part of their standard of care will receive an ENIVO™ System (‘ENIVO’). The ENIVO system is a new type of device that may aid in the removal of fluid from a surgical site and reduce the risk of fluid (seroma) formation. The ENIVO system is a battery-operated vacuum device that acts to remove fluids from around the surgical site and replaces traditional surgical drains, that would have been used as part of a simple mastectomy procedure. The main differences between a traditional surgical drain and the ENIVO system are: • The ENIVO system is battery operated while a normal surgical drain is not. • The ENIVO system includes a small patch of sterile material that is made from animal (sheep) tissue and is designed to sit between the silicon drain tube and the tissues of the surgical site. A Primary Investigator, Sub Investigator (surgeons) and Study Team have undergone training to use the ENIVO device as part of a simple mastectomy procedure. This training was completed at least 5 weeks prior to the enrolment of the first participant and included placement of the ENIVO device, operation and maintenance and follow-up care. Participants will undergo a screening that includes medical history review. The anticipated duration of screening visit is <60 mins. Once screening is complete, participants will undergo simple unilateral mastectomy, per the surgeon's typical protocol. During the surgical procedure you will have an ENIVO system placed in the surgical site rather than a normal surgical drain. The surgeon will only use one ENIVO system during your surgery. Using the ENIVO system instead of a standard surgical drain will not change your surgery, the time of the surgery, or the length of your hospital stay. With the ENIVO implant device being placed intra-operatively the anticipated duration of surgery is ~120 mins. All participants shall receive standard post-operative care. All patients shall remain in-patient overnight, and then may be discharged at the surgeon’s discretion. Participants will return to the clinic for follow-up visits at: Short-term Post-operative: • 1 week post-operative (±2 days) (‘dressing change assessment’) • <2 weeks post-operative (‘drain removal assessment’) Long-term Post-operative: • 1 week (±2 days) post drain removal (‘imaging assessment’) (~ 3 weeks post-operative) • 3 months (‘long term follow-up assessment’) These visits will be conducted in person. Participants and the research team will answer structured questions relating to the performance of the ENIVO system, including fluid output volume, which shall be recorded daily. Surgical drains are typically removed <14 days after a mastectomy procedure, and clinical decision making is based on the daily fluid output (mL). Fluid output shall be recorded by the Study Team during the course of post-operative treatment. At the discretion of the Investigator, ENIVO drainage catheters will be removed when daily drain fluid output is <30 mL/24 hour. In the event that drain fluid volume does not reach <30 mL/24 hour within 14 days, drain removal shall fall to the discretion of the Investigator and Surgeon. The time to drain removal (days) shall be recorded by the study team. During the course of treatment (out to and including 3-month long-term follow-up) surgical site occurrences (SSO) will be monitored and recorded. SSO shall include those commonly associated with post-operative complications, including seroma, hematoma, infection, lymphedema, tissue necrosis, dehiscence. During follow-up visits patients will also be asked to qualitatively score their pain. Participants will be asked to complete structured questionnaires to assess the ENIVO system useability and functionality during the dressing change assessment and drain removal assessment. De-identified photographs will be taken for documentation purposes. An intra-operative photo will be taken by the Study Team to illustrate surgical placement of the ENIVO device. At subsequent post- operative visits, the wound and drain site will be photographed. No photographs will show the participants face. Any distinguishing features (e.g., tattoos) will be removed or obscured from the digital images.