How XR assistance can help localization of internal lesions?

The term XR (Extended Reality) is an umbrella term that integrates VR (Virtual Reality), AR (Augmented Reality), and MR (Mixed Reality).

With the advancement in XR technology, it has now gained the potential to change the Reality of Operation Theatre.

What do these words mean individually?

VR (Virtual Reality)

VR generates an immersive, completely artificial computer-simulated image and the environment with real-time interaction.

AR (Augmented Reality)

MR (Mixed Reality)

The traditional way of localizing lesions or disease sites in the body through intact skin

Photo by Los Muertos Crew from pexels

It takes years of learning and training for surgeons to be able to have the knowledge of surgical anatomy and to gain the operative skills to locate and operate accurately at the disease site. The process of localization includes a physical assessment which is further combined with the data from different imaging modalities like X-Ray, USG, CT, and MRI.

How is the physical assessment done?

It is a systematic step-wise data collection process that uses the senses of sight, hearing, touch, and smell and involves the following 4 techniques

Inspection - By using vision in the presence of adequate light, body parts are inspected to identify the abnormality - color, shape, symmetry, movement, pulsation, and texture

Palpation - By using hands and the sense of touch, body parts are palpated. It gives the data about the outline of organs (Liver, Kidney, Thyroid, Spleen, etc) and also helps to assess the physical properties like temperature, texture, turgor, and distension which helps the surgeon to determine the disease site and confirm the shape and boundaries of the lesion.

Percussion - By using one or both hands, this technique is used to strike the body surface to produce a sound called a percussion note that travels through body tissue. The character of the sound determines the location, size, and density of the underlying structure to verify abnormalities. An abnormal sound suggests a mass or substance like air, or fluid in an organ or cavity.

Auscultation - By using the sense of hearing and using a stethoscope, the body is auscultated. Different body systems have their own characteristic sounds. The sound of a heartbeat, breathing, or intestinal movement varies from one another. It is important for the surgeons to know the normal sound and distinguish it from the abnormal.

Difficulties in the traditional method

A surgeon has to first examine a patient before the surgery, confirm the diagnosis using imaging modalities, and then proceed with the operation. To master these above skills takes years of experience and practice.

Most medical facilities only offer 2-dimensional imaging modalities ( A scan or an x-ray) and the surgeon has to create the 3D image in their mind. Because of the limited visibility, complex anatomical structures cannot be visualized easily such as nerves, arteries, and veins in the Head and Neck region or in the abdomen and pelvic regions where multiple organs are present in a compacted manner.

To add to that, all human bodies are not the same. There are many individual variations in anatomical structures which cannot be assessed properly with just physical assessment especially lesions that are not superficial or a covered by bones like brain tumors or deep-seated intra-abdominal abscesses.

Photo by EVG Kowalievska from pexels

So, it becomes very difficult to localize a lesion or disease site from above the intact skin layers. Often the surgeon has to take multiple attempts or do a complete exploration of the disease site which not only lengthens the procedure but increases the risk of injury to nearby structures (injury to normal brain tissue while trying to remove a tumor or injury to intestine while draining an intra-abdominal abscess)

XR to the rescue...

XR provides the perfect solution to all the above-mentioned problems. Doctors don't have to rely on 2-dimensional pictures anymore as with the help of XR, Medical images are used to create virtual 3D models which can be laid over the patient during surgery by using projector-based AR. The projector is integrated into the OT environment which directly projects the information onto the object of interest that is the patient's body on the OT table and combines physical and virtual space.

The surgeons can now plan the procedure ahead of surgery by interacting with 3D anatomical modeling and understanding the patient's unique anatomy which increases the precision, accuracy, and outcome in the operation room.

XR technology is already getting popular in the field of spine surgery and has immense potential for growth in other branches of surgery as well

References

Augmented and virtual reality in surgery-the digital surgical environment: Applications, limitations and legal pitfalls. Ann. Transl. Med. 2016, 4, 454 [Link]
XR (Extended Reality: Virtual Reality, Augmented Reality,Mixed Reality) Technology in Spine Medicine: Status Quo and Quo Vadis, J. Clin. Med. 2022, 11, 470. [Link]