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.

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Surgical Video Recording: How I Do It

A number of people have asked how I go about video-recording surgeries... Beyond having hospital administration on board as well as obtaining appropriate consents from all involved parties, the technical aspects are actually quite straightforward.

I have tried all sorts of methods in order to obtain the closest and most vivid images possible. I tried cameras mounted on the surgical headlight which did work... but there was too much motion artifact leading to unusable footage. Even though I thought my head was absolutely still, it really was not.

What I found worked best is using the video tower used for sinus surgery in my hospital with the camera-head attached to the overhead light-handle. Thankfully, my hospital uses HD equipment with 3CCD camera-head, so the video footage is spectacular. And because the camera-head is mounted on a light-handle, the footage obtained is absolutely still.

The footage is recorded digitally directly onto a hard drive which I than transfer to a USB thumb drive.

Along with this setup, I have a roaming individual with a hand-held camcorder to obtain different angled shots to add variety to the final movie.

So that's how I now do it!

The specific video equipment I use is a Conmed Linvatec HD System... however any sinus surgery video equipment should work even if analog.

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Dr. Chang Mentioned on NBC News Regarding Sound of One's Voice

Dr. Chang was mentioned today in a NBC News article on their popular Body Odds section. The article entitled "why you hate the sound of your own voice" describes why people sound and often dislike the way their voice sounds on a recording.

What we hear when we speak, however, is air- and bone-conducted sounds. Vibrations from our vocal cords directly reach the cochlea. Our skulls deceive us by, in fact, lowering the frequency of these vibrations along the way, which is why we often perceive ourselves as higher-pitched when we listen to a recording.  

“When [someone] listens to a recording of their voice speaking, the bone-conducted pathway that they consider part of their ‘normal’ voice is eliminated, and they hear only the air-conducted component in unfamiliar isolation—what everybody else actually hears,” says Dr. Chris Chang, an otolaryngologist at Fauquier Ear, Nose & Throat Consultants in Warrenton, Virginia. [link]

I wrote a more comprehensive blog article on this phenomenon here.

In any case, very cool I got quoted!!!

Source:
Why you hate the sound of your own voice. NBC News 4/2/13

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Video of Epiglottitis

The normal epiglottis is a very thin flap of tissue that closes over the windpipe when swallowing preventing food/liquids from going down the wrong way. Shown by the blue arrow in the picture, when the epiglottis becomes infected, it can swell in size to even obstruct the airway leading to death by asphyxiation. Indeed, epiglottitis is what is thought to have killed our first President George Washington.

Fortunately, epiglottitis is quite rare ever since the introduction and regular use of the Hib vaccine in the 1980s. Although rare, it is a problem that still occurs intermittently even today. Each time I've encountered it in the past, I unfortunately was always in a situation whereby video recording of the endoscopic exam was not possible.

Until one day, a patient with epiglottitis did walk into my clinic and I WAS able to video-record the endoscopic exam.

Briefly, this patient developed a severe sore throat with difficulty swallowing that occurred suddenly over a 24 hour period of time. Patient reported the severe sore throat was localized to the base of tongue region.

Without further ado, here's the endoscopic examination both before treatment and than again 1 week later after a course of antibiotics and steroids.

Note the markedly swollen epiglottis before treatment. Even after treatment, the epiglottis is still mildly swollen though much improved. Normal is shown in the picture above.

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Video and Audio Recording with RCA Connectors: Primer for Surgeons

In the medical world, video recording of surgical procedures is not unusual, especially when it comes to endoscopy.

A camera attached to an endoscope throws up a live image to a screen for the surgeon (and others) to watch. Video output for recording is now standard in such situations.

The monitor where the endoscopy procedure is viewed itself contains video output plugs.

The endoscopy equipment itself like the KayPentax EPK-1000 contains not just one video output, but 3... Two S-video and one RGB.

As such, one could hook up literally any type of recording device and get a beautiful video copied into any type of media very easily whether laptop computer, VHS, CD, thumb drive, etc.

HOWEVER, audio recording simultaneously with endoscopy is not typically a built-in feature and as such requires some MacGyver action.

Why in the world would a surgeon want to record audio? Well, take ENT surgeons who perform vocal cord procedures where the voice is the main outcome measure. It would be great to be able to record not just the video, but the audio of the patient's voice as the procedure is performed.

So what to do?

The simplest way to record audio and video is to take a camcorder and record the screen. The camcorder will be able to record the video (via shooting the monitor) and has built in microphone to record the surrounding audio. One can also attach a lapel microphone and plug it into the audio jack of the camcorder if available.

The downside with this simple method is the video quality. You are after all recording a screen rather than getting the pure digital video signal which would provide the best video picture.

Well, the surgeon will need to obtain a digital AV converter box which has the ability to merge separate video and audio signals and merge it into a single AV signal that is then fed into a computer to record. With this setup, the computer is tricked into thinking the video and audio as coming from a single source like a camcorder.

The problem is that all AV converter boxes (as of Nov 2011) utilizes RCA audio ports (red and white).

One can not simply buy a microphone with appropriate RCA adapters and plug it into the AV converter box. IT WILL NOT WORK!

Why? Because RCA connectors contain no power. Typically, RCA connectors go from something that already has a power source like a DVD player, camcorder, or TV. The current crop of digital AV converter boxes assumes that the user is trying to copy a movie or show onto a computer.

But for the surgeon, that's not what is occurring.

We literally just want to connect a microphone (which inherently has no power supply) to the RCA audio ports on the AV converter box.

In order to do this, a power supply needs to be provided to the microphone BEFORE plugging it into the RCA ports.

What is this power supply unit? It's called a microphone pre-amp.

So the connections go something like this:

microphone on patient --> microphone pre-amp --> AV converter box --> computer to record

A variety of plug converters will be required in order to plug each component to each other.

For those who want to duplicate what I've specifically done, here are the components (Amazon links provided below):

1) Microphone - Olympus ME-51S Stereo Microphone
2) Microphone Pre-Amp - ART Tube MP Studio Mic Preamp
3) AV Converter Box - Canopus ADVC110 Converter

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Why Does My Voice Sound Different on Recording and Treatment Options

Every so often, I have a patient who presents to my office with a complaint that their voice sounds different on recording than what they themselves hear.

In particular, singers who come in state specifically that their vocal recordings sounds slightly flat when they thought they were singing in perfect pitch.

So why does this happen? Unfortunately, it is physics and fundamentally integrated to how the ear, skull, and sound transmission work. In other words, it can't be "treated" with surgery or medications.

What other people hear when you sing or talk is air conducted sound that gets transmitted through the ear canal, eardrum, middle ear bones, and ultimately to the cochlea hearing organ (pathway A).

Image by Chittka and Brockmann Modified from Wikipedia

The sound the individual singer/talker hears is not only sound transmitted via the air (pathway A) but also by vibration of the skull itself directly to the cochlea hearing organ bypassing the outer and middle ear completely (pathway B). The mechanical properties of the skull enhance the deeper, lower-frequency vibrations.

Therefore, when a talker/singer listens to a recording of their voice speaking/singing, the bone-conducted pathway that they consider part of their “normal” voice is eliminated, and they hear only the air-conducted component in unfamiliar isolation (what everybody else actually hears).

SO... what is a singer/talker to do if they are disturbed by the way they sound to others? Particularly, what is a singer to do when they always sing a little flat when they truly think they are singing in pitch?

One can wear earplugs in order to hear only bone-conducted vibrations and get used to their alter-voice and undergo speech/voice therapy. OR... accept that their voice IS different.

For singers, I highly recommend using HearFones Headsetwhich is a funny looking head device that allows an individual singer to hear what they really sound like and more importantly what the audience would hear! In addition, while using HearFones, the singer would be able to hear himself more predominantly over the rest of the ensemble thus helping him to improve the quality of his/her individual vocal quality output.

Over time, singers will be able to automatically adjust their singing such that they no longer will need such a device to sing in tune with others when in familiar surroundings. BUT... in new environments (new concert hall, outdoor arena, etc), it is not unusual that their singing may become off again...

This is why professional singers often wear earpieces that convey sounds recorded by microphones placed in the audience... and also why they sometimes sound flat and out-of-tune when they don't!

It's also why it is VERY important to rehearse in a new place before a concert.

On a related note, most individuals state that they do not "like" they way they sound on a recording. However, according to one study, people unconsciously prefer their recorded voice over others.

Of note Dr. Chang was mentioned on NBC news regarding this question in this story.

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