“Keyhole” surgery – a catch-all term used to describe a variety of minimally-invasive surgical therapies – has become a field of rapid innovation and the treatment of choice when it is available. On the supply side, growth is fueled by advances in surgical technique as well as in imaging, instrumentation, and robotics; on the demand side, increasing chronic disease, an aging population, and increased access to health insurance have helped drive growth as well.
Benefits are obvious. At its surface, minimally-invasive surgery (MIS) appears to be the very embodiment of the principle to do no harm. Small incisions or punctures mean less trauma to healthy tissues and reduced infection risk. Less bleeding means quicker recovery and less need for transfusions. Decreased pain means reduced analgesia and the risks it carries. And patients who, because of comorbidities, are unsuited for conventional open surgeries may still be afforded treatment via MIS.
However, in actual fact, today MIS falls short of fulfilling these promises. Several significant drawbacks limit its effectiveness and availability. Let us examine some of the limitations of MIS with respect to open surgery, and take a look at their implications.
In open surgery, the anatomy is exposed and plainly accessible to the surgeon. Lesions can be examined directly visually and by touch. In contrast, in MIS imaging is limiting. Even as advances in endoscopy, X-ray imaging, and ultrasound have been made, the fundamental nature of these imaging modalities is such that clinicians must expend significant mental energy interpreting the images they see.
Endoscopy, laparoscopy, and other similar imaging modalities provide the user with a live image fed from inside the body. Modern scopes use miniaturized cameras to image in very high resolution with full color. However, imaging from within body cavities is hardly natural and intuitive. It is the clinician’s task to make out the forest from the trees, as it were.
Modalities such as ultrasound and fluoroscopy provide the means to visualize inside the patient’s body non-invasively, and this has supported the development of advanced minimally-invasive therapies. However, ultrasound and X-ray images are no more intuitive than the images provided by endoscopes. Even with new enhancements in image processing and fusion overlays, the clinician must interpret a two-dimensional image to appreciate a complex three-dimensional structure. At times, the anatomy is so complex as to contraindicate MIS due to imaging limitations.
Moreover, while noninvasive or minimally invasive, X-ray based imaging modalities do cause harm. They expose the patient – and frequently clinicians, nurses, and other caregivers – to ionizing radiation. This poses risk of acute injury as well as an increased risk of cancer. Additionally, common and effective contrast agents needed for visualizing soft tissue with X-ray imaging are nephrotoxic, risking kidney damage and even contraindicating their use in patients with poor renal function.
Interpretation and intuition challenges go hand in hand with challenges associated with control and precision. Without direct access to the anatomy being treated, in MIS clinicians make use of externally-operated tools. Snares, scopes, and laparoscopic instruments allow the interventionalist to access, grab, cut, and ligate through small punctures or incisions, or even natural body orifices, but they require extensive training to operate. The unnatural feel of these instruments demands extreme concentration and skill from the operator.
The brain’s visual perception system and fine motor controls are the product of eons of evolution, and they are exquisitely suited to the tasks required of a surgeon performing a conventional open repair. With visual and tactile access to the anatomy, the surgeon’s natural hand-eye coordination leaves nearly all the clinician’s attention for the patient and the procedure. With MIS, this natural ability cannot be leveraged the same way, and therefore the clinician’s attention is diverted by interpreting images and controlling instruments.
These challenges prevent MIS from fully making good on the promises of minimal harm and maximum access to care. Happily, innovation in medical devices, imaging, and techniques has started to show promising new developments towards achieving MIS’ touted benefits:
- Augmented reality (AR) holds tremendous promise; augmenting a clinician’s eyesight with computer-generated images, AR can bring about in MIS many of the same visualization advantages of open surgery. The Magic Leap One and Microsoft HoloLens headsets provide spectacular computational capability in self-contained but networkable AR headsets. Recently the Novarad OpenSight system, leveraging the HoloLens for surgical planning, achieved FDA clearance. Companies like Medivis, Stryker, MediView XR, and Centerline Biomedical are working hard to bring about the leap from AR planning to AR surgery in a variety of specialties.
- Robotic surgery continues to be an active area of development, and has the potential to address the challenges of control and precision with minimally invasive instruments. Providing intuitive controls that are relayed precisely, robotics allows an interventionalist to recover some of the control lost in MIS. The already established da Vinci technology from Intuitive Surgical is joined by Auris Health’s Monarch system, and both continue to evolve to provide stronger and more intuitive control for endoscopic procedures. Hansen, Verb Surgical, and countless innovative startups are energetically developing novel and capable robotic technologies.
- X-ray technology is improving all the time, allowing better visualization with less radiation. Even so, continued advances in radiation protection are essential to truly minimize the unintended harm associated with many image guided interventions. Biotronik’s Zero-Gravity system and other advanced shielding technologies can reduce exposure to caregivers. Robotic systems can do the same. And image guidance innovations, ranging from fusion imaging to non-radiation-based technologies like Centerline Biomedical’s IOPS, FORS being developed by Philips, and Johnson & Johnson’s Carto 3 can protect the patient as well.
Together, these paint a striking vision of the future of MIS. Non-radiation navigation combined with AR and robotics can help bring about an operating environment in which a minimally invasive intervention transforms into a safe and intuitive procedure that not just looks but also feels in many ways like an open one, unlocking the true potential of MIS.