Increased longevity and survival after major illness also result in many surgical patients being more likely to have co-morbidities. How to understand, model and predict the influence of co-morbidities and the system-level impact of surgical intervention, as well as establishing new surgical pathways in the context of ageing and the increasing prevalence of chronic diseases, represent major research challenges and a national health priority. At the Hamlyn Centre, we are developing new surgical sensing technologies to minimise post-operative complications, avoid re-admission, and enhance patient recovery and quality of life. It builds on the extensive complementary experiences of the team in sensing for healthcare with a strong emphasis on technological innovation and clinical translation - i.e., “from sensor to real-time information, to clinical knowledge and stratified patient management”.

Sensing for Detecting Surgical Site Infection

Infection within or near surgical sites occurring within 30 days of the operative procedure, so termed Surgical Site Infection (SSI), represents over 15% of all nosocomial infections. Data from the Nosocomial Infection National Surveillance Service (NINSS) further confirms the significant negative health impact of SSIs, leading to prolonged post-operative length-of-stay, drastically escalated health care expenditure, higher re-admission rates and poor outcomes following surgery. Similarly, despite preventative counter-measures, Catheter Related Sepsis (CRS) resulting from indwelling urinary and (especially) vascular catheters accounts for the vast majority of deaths associated with hospital-acquired infections. The transition from contamination to established infection is a process that occurs early, however most SSIs and CRSs are detected late. There is a narrow window during which elimination of contamination is possible (“decisive period”) prior to the development of an infection. However in current practice, it is often not until local and systemic signs and symptoms develop as a result of established infection, that SSI or CRS is diagnosed.

Monitoring Tissue Viability

Another important aspect of sensing for surgery is concerned with monitoring tissue viability. This is related to the detection of wound dehiscence, anastomotic leakage and graft rejection. In Gastro-Intestinal (GI) surgery, for example, this may manifest as a failure of GI continuity in which GI contents are able to pass through a physical defect in the anastomoses, which is associated with morbidity, poor functional outcome, increased risk of death and increased risk of local recurrence in cancer patients. Early detection may trigger second line investigations, and facilitate conservative manoeuvres to mitigate risks. In reconstructive procedures where autograft transplantation occurs, such as in autologous breast reconstruction (microsurgical flaps), there is a significant risk of insufficient tissue oxygenation due to tension, torsion or thromboembolism. Current practice is associated with poor salvage rates should there be an ischemic event due to late detection of transplant failure. In this regard, continuous assessment based on tissue flow and haemodynamics may provide objective data regarding flap viability and/or compromise for mitigating the risk of post-surgical complications. 

Our vision is to develop new sensing technologies to ensure early detection of surgical site infection, continuous monitoring of tissue viability, and quantitative assessment of functional restoration. Through an integrated programme of engineering research and development of a novel real-time active sensing paradigm, the project aims to transform the care pathways for surgery with greater consideration of personalised treatment, system level impact, real-time response to complications, patient concordance and quality of life.