That’s Barbaric!

I recently watched Dances With Wolves. That film opens with a stark illustration of how primitive and awful 19th century battlefield surgery was. I was reminded of the tools physicians used (see photo) and thought that after a week of surgery those tools could be taken home and used for weekend carpentry projects.

At the other end of the cinema scale there is the Star Trek series which was initially set in the 23rd century. There science has advanced to where malfunctioning organs can be regenerated, surgery is done without breaking the skin and if you lose a limb in an accident, a new one can be grown.

There is a great scene in the 1986 movie Star Trek IV: The Voyage Home where Dr. Leonard McCoy has traveled back to the 20th century and comments on the medical procedures he finds there, proclaiming, “That’s barbaric!.”

We are in the 21st century now and sort of half way between surgery done with hacksaw or tricorder. I asked Jude (judeintime in SL), who is a graduate student in biomedical engineering, an to tell us about the current state of surgery.

“Robot* assistance has been rapidly adopted for a wide array of surgical practices, introducing improvements in precision and flexibility. A prominent system utilized in minimally-invasive procedures in hospitals internationally is the da Vinci surgical system, developed by Intuitive Surgical. Please watch the following YouTube video for reference: da Vinci® Surgery – How It Works.

An iteration of the system consists of two major components:

• A surgeon’s console – that houses control handles, a visual display and user interface panels.
• A patient-side cart, that hosts two or three arms that manipulate cable-driven surgical instruments and one arm that manipulates a video endoscope.

In the operative setting, the surgeon sits at the console and manipulates the arms and instruments through the control panels. The visual display relays a live depiction of the surgical site obtained through the endoscope. Minimal-invasiveness is the huge advantage here. Where typical surgical tools in procedures like laparoscopies are long and do not possess joints – thereby only allowing the transmission of translational and rotational movement, the da Vinci system also transmits flexion (1 minutes and 20 seconds into the video linked above: observe the way the tool bends inwards, like your finger or elbow can – that’s flexion {Note: the tool here is also undergoing rotation about its longitudinal (length-wise) axis, and at 1 minutes and 30 seconds, the up and down and in and out movement of the arms – that’s translation} ). This provides the surgeon easier access to the surgical site as well as access to specific regions within the surgical site, without the need to extensively move instruments. It allows for small incisions for the insertion of instruments and reduces the chances of damage to healthy tissue (minimal-invasiveness). The system also utilizes computational methods to avoid the transmission of tremors from the surgeon’s hands to the arms, improving precision and safety.

The da Vinci system isn’t phenomenally new, having been approved by the FDA for general surgery in the year 2000. I can, however, associate a number of recent and exciting technical developments for surgery with this system alone. Remember the tool depicted at 1.30 in the earlier video? Being cable-driven, it harbors a number of mechanical parts like screws and pulleys – which are subject to wear over the course of its use. Any damage to or disassembly of such a tool creates the risk of tiny foreign objects ending up in the body, which is extremely dangerous. Enter soft robotics – systems constructed with materials that have similar mechanical properties to living tissues. The art of paper folding, origami, has inspired a number of soft robot designs. Foldable structures can be manipulated pneumatically or thermally to achieve the flexion demonstrated by the da Vinci system. There are video examples of these online: thermally actuated and pneumatically actuated.

(I actually built one of the latter at home for a project, I came up with a folded structure with some thick {approx. 160 gsm} paper, enclosed it in some food wrapping with the end of the structure attached to the nozzle of my vacuum cleaner. The suction compressed the wrap and the resulting force made my structure flex, {If you try this, I advise making a hole in the food wrapping to make sure it isn’t airtight, so you don’t damage your vacuum cleaner})

Soft robots allow for greater flexibility, these can even be swallowed or delivered through the bloodstream to clear blockages, heal wounds or deliver drugs. Flexible manipulators built using soft robots allow for increased safety, but to ensure they are compatible with surgeries introduces engineering challenges, like miniaturization and preserving material strength.

A recent upgrade to the da Vinci system, named Firefly, enhances the visual guidance capabilities provided by the endoscope using fluorescence imaging. A fluorescent die – Indocyanine green (ICG), is first injected into the bloodstream, rapidly binding to plasma proteins. During the surgery (At a specified time period after injection), Near Infrared (NIR) light is delivered through the endoscope onto a region of interest. NIR light is capable of penetrating tissue several millimeters below its surface. At a specific wavelength within the NIR spectrum (approx. 820nm), ICG becomes fluorescent. The fluorescence light it emits is detected, enabling the visualization of embedded strictures like blood vessels that would ordinarily be visible to the naked eye (under visible light). Abnormal vascular characteristics for example can therefore be detected for the identification of cancers or cysts. The growth of tumors is strongly dependent on angiogenesis – the formation of new blood vessels for oxygen and nutrient delivery – which cancers demand for their growth. An increased density of blood vessels is one way therefore to detect tumors. This can be enabled by fluorescence imaging, which is one of a number of advanced imaging methods that are being utilized or developed for the detection of abnormalities in the body for better surgical outcomes.

Further challenges arising from the implementation of the aforementioned technologies in surgery may lead to the use and development of other impressive technological advancements. Successful surgeries with the da Vinci system are also dependent on an operator’s proficiency. The use of virtual reality, where the surgeon is immersed in a computer generated environment by means of a headset and haptic gloves (one possible setup) may be used to train surgeons and ensure they are comfortable with equipment before the actual procedures. Artificial Intelligence (AI) may be used to aid surgeons in the diagnosis of images obtained in the midst of surgery, facilitating the discrimination of unhealthy entities for more effective resections and better post-surgical outcomes per say. The possibilities go on and on. Which brings me to the awkwardly placed asterisk in my introduction:

* I feel somewhat uneasy about the use of the word “robot” with the da Vinci system, even though it’s often used to describe it in literature. To use it implies that a system is autonomous to a certain degree. This isn’t the case with the da Vinci system. That said, with advancements in AI and impressive developments in machine operated equipment, perhaps robotic surgery, true robotic surgery, is a possibility after all.”

Jude’s References

• DiMaio, Simon, Mike Hanuschik, and Usha Kreaden. “The da Vinci surgical system.” Surgical robotics. Springer, Boston, MA, 2011. 199-217.
• Schmitt, François, et al. “Soft robots manufacturing: a review.” Frontiers in Robotics and AI 5 (2018): 84.
• Meershoek, Philippa, et al. “Multi-wavelength fluorescence imaging with a da Vinci Firefly—a technical look behind the scenes.” Journal of Robotic Surgery (2020): 1-10.
• Boni, Luigi, et al. “Clinical applications of indocyanine green (ICG) enhanced fluorescence in laparoscopic surgery.” Surgical endoscopy 29.7 (2015): 2046-2055.
• Egloff-Juras, Claire, et al. “NIR fluorescence-guided tumor surgery: new strategies for the use of indocyanine green.” International journal of nanomedicine 14 (2019): 7823.

References

• MedTech Memoirs: Civil War Era Surgical Tools, Sam Brusco, Medical Design and Outsourcing, August 26, 2015.
• Image source – Surgical Instruments, 6/13/1861 – ca. 1865, National Archives.
• Star Trek IV: The Voyage Home (film), 1986.
• Medicine past, present, and future: Star Trek versus Dr. Kildare and The Knick, David Gorski , Science-Based Medicine, September 15, 2014.

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