Intraoperative blood vessel detection and quantification: a Monte Carlo study

With better surgical outcomes, quicker recovery times, decreased postoperative pain, and reduced scarring at the surgical site, the application of minimally invasive surgery (MIS) has gained a lot of prominence in the last 30 years. This change in surgical practice has taken away the ability of a surgeon to palpate for the presence of a blood vessel as would occur in an open procedure. They instead must rely on a laparoscopic video camera feed that unfortunately cannot detect the presence of a blood vessel hidden beneath tissue. In certain scenarios, a surgeon can accidentally cut a blood vessel, which can lead to severe, even fatal, complications. Here, we show that by adding a near-infrared LED and a photodiode onto the opposing jaws of laparoscopic graspers, blood vessels buried under tissue can be detected. We show the results of Monte Carlo simulations to support our theory that the blood vessels ranging from 3 to 6 mm buried under up to 1 cm of tissue can be detected and quantified. This technology could be added to already existing laparoscopic tools that have limited surface areas on the jaws to assist surgeons during MIS procedures.

Blood vessel detection, localization and estimation using a smart laparoscopic grasper: a Monte Carlo study

For centuries, surgeons have relied on their sense of touch to identify vital structures such as blood vessels in traditional open surgery. Over the past two decades, surgeons have shifted to minimally invasive surgical (MIS) approaches, including laparoscopic surgery, which include benefits such as less scarring, less risk for infection, and quicker recovery times. In fact, some surgeries such as cholecystectomies have seen more than an 80% adoption of this technique because of those benefits. However, due to the fundamental challenges associated with using laparoscopic surgery, there has been a lower adoption in more complex specialties, such as colorectal and thoracic surgery, where the field of surgery has bleeding, fat, scar tissue, and adhesions. These problems are exacerbated by complicating factors such as inflammation, cancer, chronic disease, obesity, and re-operations. Importantly, surgeons will often convert from laparoscopy to open surgery if they can no longer proceed using the minimally invasive approach because of issues described with these complicating factors, thereby negating the benefits that the patient would have seen. When the surgeon does attempt these procedures with those issues, the surgery takes on average 30 min - 1 hour longer. A new method by which surgeons can visualize structures like blood vessels could reduce the conversion rates and operating time, thereby driving a greater adoption of laparoscopic surgery in these complex procedures. Here, we show that by adding near infrared (NIR) LEDs and a linear image sensor onto the opposing jaws of the laparoscopic graspers, blood vessels that are embedded within tissues can be detected and localized efficiently, even those not visible using current imaging techniques. We show the results of Monte Carlo simulations to support our claim, including that blood vessels ranging from 2 to 6 mm and buried under up to 1 cm of tissue can be detected. We also report developing a smart grasper handheld prototype to run ex vivo experiments. The results of these experiments matched with those of the Monte Carlo simulations and the estimated blood vessel size showed a strong correlation with the actual size. This technology will be incorporated into already existing laparoscopic tools to assist surgeons during MIS procedures.

Multi-modal magnetic resonance elastography for noninvasive assessment of ovarian tissue rigidity in vivo

For centuries, physicians have relied on touch to palpate tissue and detect abnormalities throughout the body. While this time-tested method has provided a simple diagnostic examination for large, superficial abnormalities, it does not permit quantifiable measurements of stiffness in deeper, small organs. Advances in noninvasive imaging to measure tissue rigidity represent important extensions of manual palpation techniques. Tissue fibrosis occurs with age in many organs; in the ovary, it is thought to be a marker of polycystic ovary syndrome and age-related idiopathic infertility, although quantitative assessment of fibrosis in this deep, abdominal tissue has not been possible. We used noninvasive methods to quantify ovarian tissue rigidity and clarify the role of tissue stiffness in reproductive health. With proper validation against accepted standards, noninvasive imaging techniques may become the quantitative counterpart to interior probing palpation methods and invasive (surgical) diagnoses, with applications across many clinical settings, including evaluation of adolescent and young adult ovarian function.