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February 02, 2014

Surgeon's Point-of-View (POV) Video Recording

Learning how to video record vivid, stable, high-def, and focussed shots from my (surgeon's) point-of-view has not been an easy endeavor due to technology limitations, though things do appear to be slowly improving. There have been pros and cons with most video-recording systems to date which I have summarized below. The "perfect" video-recording system has yet to be developed which must include all these elements:

• Wearable on headlight or glasses
• Camera located between the eyes that is maneuverable to adjust recording angle
• Head-up view to see what is being recorded real-time
• Manual white balance adjustment
• Manual exposure adjustment (bright lights used in surgery often confuse auto-exposure settings which result in washed-out pictures)
• Auto-focussing with adjustable zoom
• VERY good image stabilization
• HD video-recording

General Problems with Head-Mounted Video Recordings

The problem with current head mounted video-recording systems including Google Glass are several-fold. First of all, no matter how good you think you are staying still, there are constant micro-motions/tremors which produce unusable erratic videos. This annoying camera movement becomes even more pronounced when using cameras with longer focal lengths which is why most head-mounted camera systems come with a fixed, wide-angle lens which unfortunately takes away from the narrow-angle, focussed shot a surgeon would like recorded.

Also, the smaller and lighter the camera, the more inferior the optics resulting in poor video quality (compared to high-resolution, 3CCD, HD recordings which is what the surgeon's want).

These short-comings are common with all head-mounted video-recording systems. Unfortunately, there are even more problems depending the camera.

Google Glass (or any eyeglass side-mounted camera)

Typically, when a surgeon operates, the surgical field (green) is a certain distance from the his/her face. When in a comfortable position, wearing any type of head-mounted camera system located on the side like Google Glass unfortunately ends up video-recording a point that is above and to the side (purple) of what is actually desired.

In order to compensate the vertical offset, either the surgeon has to flex the head more or move the eyeglass down towards the lip.

To adjust the horizontal offset, the surgeon would have to turn and move the head to one side such that the camera has a more direct line shot into the surgical field... but that would mean the surgeon would be operating off-centered, almost looking over one shoulder.

Although doable, this is far from perfect or comfortable.

Central Head-Mounted Video Camera Systems

There ARE video-recording cameras that contain a camera that can be placed centrally over the forehead or between the eyes including Luxtec and SurgeonCam which are mounted on the headlight and PivotHead glasses (among others) where the camera is built into the frame between the eyes.

The headlight mounted systems'  camera angle can be adjusted to provide a more precise POV recording, but the general disadvantages of body-worn cameras still apply with constant erratic motion and wide-angle shots that do not specifically focus in on the surgical field.

The PivotHead glasses do provide perfect central shots, but still suffer from a vertical offset (orange) which cannot be adjusted like the headlight mounted systems.

Overhead Mounted Camera Systems

For the same reason the best photos are obtained by cameras fixed to a tripod, the best videos are often obtained by cameras fixed into position by a stationary object.

One object cameras can be attached to are overhead fixtures.. specifically the operating room lights.

Such cameras are attached typically to the light-handle of such overhead operating room lights which are directed down into the surgical field. Such systems provide excellent focussed, stable, high-quality video-recordings with one BIG disadvantage. The surgeon's head keeps getting in the way.

Also, the light-handle is positioned for optimal lighting of the surgical field... not optimal framing for capturing good videos.

Bed-Mounted Camera Systems

Using a Thompson Laparoscopic Retractor System, the video camera can be attached to one of the articulating arms and adjusted sterilely as needed. Using this retractor system can allow the camera to be positioned independently of the overhead operating room lights and to be as close to the surgical field as necessary.

The video is limited by how good the camera is that is attached. The best one I've been able to find is the Sony HXR-MC1 which incorporates a large-sized lipstick camera that is attached to a controller where manual controls for focus, zoom, white balance, exposure, etc can be made. Other than the built-in LCD screen, there are included plugs (Component, RCA, and with adapter S-Video) that allow what the camera is recording to be thrown up onto a large screen.

Other wireless video lipstick cameras are now being produced, but lack manual controls to adjust zoom, white balance, and exposure. Some offer real-time video display so it may be just a matter of time before all other manual controls found with the Sony HXR-MC1 become more widely available.

The main disadvantage with this setup is that the setup itself can get in the way of the surgeon.

Conclusion

So there you have it... No perfect surgical POV video system yet... Maybe in the next few years if technology keeps moving the way it is.
Fauquier blog
Fauquier ENT

Dr. Christopher Chang is a private practice otolaryngology, head & neck surgeon specializing in the treatment of problems related to the ear, nose, and throat. Located in Warrenton, VA about 45 minutes west of Washington DC, he also provides inhalant allergy testing/treatment, hearing tests, and dispenses hearing aids. Google+ Christopher Chang, MD Bio

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