SAGES VIDEO PRODUCTION GUIDELINES

INITIAL PLANNING & RECOMMENDATIONS

CONCISE MATERIAL

A good videotape is most effective in conveying an intended message when it is well-paced, cleanly edited, and clearly narrated with high quality images that are well defined, sharply focused and in true colors.

Many videotapes submitted for presentation are longer than necessary and contain footage that does not contribute to the primary topic. The intended audience should be considered, e.g. whether the film is for surgeons that perform the operations presented or if it is intended for other audiences, e.g. surgeons new to the approach, or the lay public. Including material to provide an overall perspective and background is important but excessive details or superfluous material can dilute the impact of the film.

For example, consider that the topic to be presented is an investigation on the effects of gas insufflation on cardiopulmonary function during laparoscopic cholecystectomy. This topic would probably be targeted toward laparoscopic general surgeons. As the topic focuses on the deleterious effects of increased intraperitoneal pressure, it may not be necessary to include, for example, pathology of the gallbladder, anatomical anomalies of the biliary tract, or the method for inserting a trocar. Although one or two minutes can be included to provide a brief overview of the technique, it would not be necessary to show each step of the laparoscopic cholecystectomy in detail. Doing so would detract from the main topic which is centered on laparoscopic insufflation and cardiopulmonary function.

VIDEOTAPE FORMAT

The highest quality videotape format is recommended when filming the original raw footage, such as U-matic (3/4 inch tape), Betacam, S-VHS, High-8 mm. VHS and 8 mm are also acceptable but are somewhat lower in quality. Original footage should not be recorded on long play (LP) or extended long play (EP) modes. When editing, use the original footage. High quality images are also of great importance, as images that are dark, grainy, out of focus, or blurred because of a fogged laparoscope dampen the effectiveness of the material presented.

USE OF GRAPHICS

Special effects can be effective if used appropriately, i.e., sparingly. They do not compensate for poor image quality nor for poor editing. One should scrutinize how effectively each graphic image communicates a message. If it does not enhance the film's message, that graphic image should be omitted. Graphics are best used for the primary message, anatomical orientation, or for simplifying a complex concept.

TECHNICAL QUALITY

Producing a high quality recording depends largely on the selection and fine tuning of equipment. It also depends on the incorporation of good laparoscopic surgical principles by the surgeon, such as maintaining proper hemostasis and a clean, uncluttered field, good "scope driving", etc. In the following description the surgeon's perspective and role in obtaining high quality original footage will be emphasized.

Image acquisition involves two paths: optical and electronic. Along each path are components which can serve as sources of image degradation.

OPTIMAL TUNING

Optimally tuning all the laparoscopic video components is of great importance and is essential in obtaining a high quality image. Laparoscopic equipment in the operating room can include components ranging from high to low end and image quality can be affected. However, regardless of the equipment's vintage, a well-maintained, properly tuned older set can provide an excellent quality image--in fact, better than a newer system that is poorly maintained and adjusted. Even when all the components are perfectly tuned there will be some degradation of image quality in the recording and subsequent generation copies will deteriorate even further. Therefore it is of great importance to optimize all of the video components prior to recording. Details of fine tuning are described later in the sections on the laparoscopic video camera and monitor.

VCR CONNECTIONS

It is important to note that the image quality produced on the television monitor may not be the same as what is being recorded. The source of this difference results from the format that the video cassette recorder (VCR) utilizes (records and plays back). As mentioned previously, higher quality recordings can be obtained using Betacam, U-matic, S-VHS, or high-8 mm; however, VHS and 8-mm can also be used.

Serial Hookup: VCR Between the Camera & Monitor: Recommended

If the VCR is serially interposed between the camera and the monitor, the recorded image will be optimal but the monitor's image will be slightly lower in quality. The obvious advantage is quality of the recorded image. An incidental advantage is that it is impossible to forget to turn on the VCR because without doing so no image can be obtained on the monitor. (However, it is still possible to forget to push the "record" button!) Some monitors can display the status of the VCR's mode or setting--e.g. whether or not the VCR has been turned on.)

Parallel Hookup: Many laparoscopic camera systems provide two S-VHS output ports, therefore the VCR can be hooked up to the camera through one port and the monitor can be connected to the camera through a different port. In this manner there is no image degradation on the monitor.

IMAGE ENHANCING

A digital enhancer can be a part of the video path to enhance the video signal for the monitor solely or for the VCR as well. The effects of the digital enhancer on the monitor's image and the recorded video image may differ, with a setting that is ideal for the monitor generally taking preference over the VCR. As that setting may result in an image that is over enhanced for the VCR, it is recommended that a test recording be made to adjust the setting for a good recorded image.

LAPAROSCOPE SELECTION

In comparing straight and angled laparoscopes, there are a number of factors to considered with regard to the recorded image. Brighter images are obtainable with the 0 laparoscope. Angled laparoscopes provide greater versatility of viewing perspectives but their images are slightly darker and less sharp at the top and bottom edges. Use of a 10 mm 0 rigid laparoscope (Hopkins rod-lens system) has the potential to provide the best recorded image.

Use of smaller diameter laparoscopes also results in reduced image quality and brightness; however 5 mm and 4 mm telescopes are generally still acceptable for producing recordings of adequate quality. With telescopes of even smaller diameters significantly compromised images are produced. Flexible telescopes which involve the use of fiberoptic bundle technology, produce a bug-eye grid image, similar to viewing through a wire screen. These grid lines are derived from the matrix (glue) material between the light conducting fibers. Images from the use of flexible scope are acceptable when there is no other alternative.

LAPAROSCOPE HANDLING

Quality Inspection of the Lenses

Both of the laparoscope's lenses, the ocular and objective, as well as its tubular body must be checked for damage (even slight damage) and for proper cleanliness. Suboptimal conditions can result in the inability to produce a sharply focused image.

Cleaning the Laparoscope's Ocular Lenses

The proximal end of the laparoscope where the camera is attached is known as the ocular lens.

The optical and electronic images are produced by coupling the video camera to the ocular lens of the laparoscope, and this junction can be a source of image degradation. Both pieces of equipment are subjected to repeated handling such as cleaning, sterilization, rough handling, or accidents. Moisture, lint, and fingerprints on this surface can blur the image.

Each time the camera is attached, the lenses of both the camera and the laparoscope should be checked to determine if they are perfectly clean and undamaged. If not, they should be cleaned and polished to a bluish sheen which can be seen by tilting the lenses at an angle to view the light reflected from the surface. Repair of a damaged laparoscope should always be performed by the original manufacturer; cheap repairs can have suboptimal results.

Cleaning the Laparoscope's Objective Lens

The same cleaning process should be performed on the distal end of the laparoscope, at the objective lens. The surface of this lens can be accidentally scratched or obscured by tissue fluids, tissue debris, etc. If not cleaned off in time, both materials can become dried onto the surface which, when cleaning, can result in the optical coating being removed from the lens and form a permanent source of image degradation.

Fogging

Fogging is another problem which generally results from a cold laparoscope being introduced into the body cavity which is warm and moist. Use of "scope warmers" and anti-fogging solutions usually eliminates this problem. Also when the insufflation gas is coupled to the laparoscope port the incoming cold CO₂ can cool the laparoscope enough to cause fogging. To remedy this the insufflation tube should be switched to a different port. If a significant amount of CO₂ escapes continuously, e.g. through a faulty trocar valve or a loose fitting port, the incoming CO₂ that replaces it will cool the laparoscope and cause fogging as well.

Smudging

Smudging of the objective lens results from inadvertently touching it to tissues; this practice also can be purposeful, e.g., it is commonly done to clear a fogged lens. While this maneuver is sometimes effective and quick, the disadvantage is that a film of tissue fluid can eventually dry onto the surface causing image deterioration.

Cleaning

The lens must be cleaned at the first opportunity. It can be cleaned internally by directly irrigating the objective lens with the suction-irrigator, or the laparoscope can be removed from the port, first wiped with a sponge (cotton gauze) soaked in warm saline, then wiped carefully with a dry one, followed by application of an anti-fog solution. The best image is obtained by frequent and direct internal irrigation with warm saline. Irrigating saline should first be warmed to near body temperature.

When pulling the laparoscope out of the port for cleaning purposes, the surgeon should make certain that the port seals are cleaned also to avoid smudging the objective lens upon reinsertion. Furthermore, as the laparoscope is pulled back, care must be taken to avoid having the port partially withdrawn as well. Otherwise, peritoneal tissue can partially cover the opening of the port, and upon reinsertion of the laparoscope, the objective lens can touch this tissue and get smudged.

LAPAROSCOPIC VIDEO CAMERA

Most laparoscopic video systems are composed of the camera head, with zooming and focusing control rings, and the controller unit. The cord from the head to the controller unit must be inserted securely, and the contact pin must be dry.

The video camera is available in a one-chip or three-chip design. The three-chip system provides better color rendering and is therefore preferred for recording. However, current one-chip cameras are nearly as good and are more rugged than the three chip versions.

Magnification can be controlled in two ways: (1) by moving the laparoscope toward (higher magnification) or away from (lower magnification) the tissues and (2) by adjusting the zoom control ring on the camera. In the latter case, the adjustment determines whether the image partially or completely fills the video monitor's screen.

When the zoom control ring is adjusted to minimum magnification (zoomed out), the image is smaller and defined by the laparoscope lenses' circular configuration--a circular image is shown on the monitor, while the rest of the surrounding area of the screen is black. A field lower in magnification results in a sharper and brighter image.

On the other hand, when the zoom control ring is adjusted to maximum magnification (zoomed in), magnification is increased but sharpness and brightness are somewhat reduced. For videotaping purposes the zoomed in or magnified image, which fills the entire screen, is recommended. Although there is some loss of image resolution, the overall perception is aided by the increased magnification.

TELEVISION MONITOR

The monitor displays the final image obtained by the optical and video components. The image qualities from the camera unit, directly input to the monitor, and the replayed recorded signal may come close but are never identical. As a rule of thumb the video recording will always be of slightly lower quality (with the exception of high-end professional systems or recorders).

The image displayed can be controlled in two ways: first by the quality of the input image and method of hook-up, and second by adjustments of the monitor controls. These adjustments are very important because an excellent quality input can be degraded to a mediocre one by poor adjustments; conversely a mediocre signal can be fine tuned ("tweaked") to an acceptable level. The monitor outputs can be used as a source of recording, but the quality will not be as high as if the direct video camera outputs are used.

The size of the monitor will make a difference in viewing the image during surgery but it has absolutely no effect on the recorded image.

SCOPE DRIVING AND CAMERA HOLDERS

A great deal of the image quality, detail and perspective is dependent on the person controlling the camera. Once the technical details are optimized, the next level of control resides with the human operators.

In one-handed laparoscopic surgery (where the surgeon controls the camera with the one hand and operates an instrument with the other), the surgeon directly controls the image being recorded.

In two-handed surgery, the camera is controlled by another person, or it can be fixed in a predetermined position by a passive scope holder, or remote controlled by a camera positioning device.

Having an experienced camera assistant is the ideal situation because the surgeon and the camera person can focus full attention on their respective tasks.

IDEAL IMAGE CHARACTERISTICS

A panoramic view is used for setup; intermediate for dissection; closeup is used for magnifying tissues for inspection and precision maneuvers such as suturing. At each stage, the anatomy of interest should be centered, but offset slightly to the left.

Often simple square bracket marks drawn on the monitor will help the camera operator keep the anatomy of interest in the center. Also, it will provide a fixed point of focus to reset the eyes' "resting focus" which has a tendency to "drift" over time.

Blanching, i.e., white washout of the picture, may indicate hardware problems (e.g. with the camera's auto iris, or the light source) and should be immediately corrected.

Sometimes tissues in the foreground, can block the light path and cause a bright area, forcing the camera shutter to cut down on the light, and make the more distant target anatomy darker. It is the camera controller's job to position the scope to avoid this "bright spot" even if it offsets the target anatomy from the center to the side. At least the image will then be properly illuminated.

FOCUSING

The second most common cause of image degradation from the laparoscope is improper focus; (the most common cause is a smudged lens). Correcting both problems is of utmost importance to remedy picture deterioration. Most laparoscopes have an infinite depth of field (the range where everything is in sharp focus) at greater distances (low magnification). As the scope is moved closer to the tissues the magnification increases and the range of focus (depth of field) becomes shallower. Therefore, the more magnification, the more critical focusing becomes. Each position needs its focusing critically re-evaluated and adjusted as needed. This has to be done manually each time the magnification is changed, particularly when moving back and forth between the closeup and medium ranges.

BACKGROUND

Another source of image deterioration can result from the color of tissues. If they are dark (e.g. the liver) or if blood clots are present, a significant amount of light can be absorbed to the point that interpretation of details becomes very difficult. For example, to suture with black silk against a dark background is exhausting since one must "hunt" for the suture. It is therefore recommended that tissue bleeders be sealed, oozing stopped and blood clots be removed either by suction and irrigation, or by wiping away with a gauze sponge. Color background material can be introduced into the field to enhance tissue contrast or be used as a point of reference. Instruments and sutures should be selected that contrast against a given background color to enhance visibility.

FILMING & EDITING

To produce a commercial or studio quality academic tape, professional video production companies should be used. A tape of such quality involves considerable expense and equipment. As it may contain expensive features, such as special effects, graphics, and other features, the results might be overdone, although it would stand out in any meeting's video program. This is appropriate if the target audience is the lay public, and is best left for mature, well-established procedures.

Simplifying the process of making a good videotape requires forethought and good timing. Expenses can be curtailed by eliminating some steps, e.g. the post-production editing phase. If the clinical surgery proceeds uneventfully and the filming is planned carefully in advance, it is possible to make the raw footage the final film.

EDITING WITHOUT ADDING GRAPHICS

The self-made video has two major components: (1) recording the surgery (raw footage) and (2) editing the tape and narrating (post production). These two processes can be combined into a direct editing and recording during the surgery, using the stop and go buttons on the laparoscopic camera head and a microphone (lavaliere). As the procedure progresses the illustrative segments are recorded in sequence and a 5 minute videotape can be made requiring only the addition of a title page and an ending page. These could be created by uncoupling the laparoscope in the beginning and at the end, and focusing it on a page where the title and credits are written. (Large bold letters are recommended. If this page is prepared before surgery, e.g. on a laser printer, it will have a more polished look; if not, it can be prepared by hand using a colored marker.)

Interesting cases, however, cannot always be predicted and should the procedure become difficult, attention must be focused on the procedure. The tape can be allowed to roll, then edited after the surgery has been completed.

Again, this can be accomplished by the A.V. professional or it can be self-made. To do a reasonable job of editing one needs two video cassette recorders (VCR), a simple VCR to play the source tape and a more sophisticated VCR for recording the edited material.

The recording VCR should have a couple of important features: (1) a pause button, (2) a "flying erasure head" for smoothing the transition between segments, and (3) a dubbing or "voice over" recording feature. Editing begins with playing the source video, making notes of the sequence of action, and recording the corresponding tape counter numbers. After selecting and timing the video segments, the tape is rewound, counter reset, and the recording of the edited material begins. Simultaneously, voice-over narration is recorded to create a clear and concise videotape. While the more interesting content should predominate, including short footage of small imperfections adds to the reality of the tape.

A 6-second title page should be recorded. The recording tape should be replayed to check if the title page was recorded successfully; then the recording VCR is paused (record/pause). Next the videotape in the source VCR, containing the raw footage, should be forwarded to a point prior to the start of the material to be transferred. Then the source tape should be played and on the recording VCR the pause mode should be released when the appropriate point has been reached on the source tape. In this fashion, the new tape contains efficiently edited material, with only the interesting and relevant segments included. The final product should be 3-10 minutes in length.

EDITING WITH GRAPHICS ADDED

The next level of sophistication can still be a self-made tape but it is a more elaborate process, involving the use of more sophisticated equipment, and can result in a more finished look. A title page is needed, and graphics overlays and animation can be included. Titles, tables, lists, and charts can be made using a computer's graphics program such as Harvard Graphics, and sent to the recording VCR as a recordable signal using a VGA-to-TV converter. As described previously, it can be edited together with the clinical footage. This editing process can be made even easier by using an "video director" device (approximately $100) that interlinks two VCRs and the computer together. The desired segments can be identified, marked and organized in the desired sequence, and with a push of a button automatically edited onto the final tape.

COMPLEX EDITING

Video editing can also be accomplished with the use of the computer (although a gigabyte of storage may be needed). A video editing board can be added to a computer to allow non-linear digital editing. The original tape is recorded onto the hard drive, with the video editing board digitizing and compressing the raw footage. Then this digitized signal is replayed on the monitor, and using an editing program the desired material is edited together and transferred onto the recording tape, along with transitions (fades in and out), graphic images, overlays, titles, credits. From this new master tape copies can be made and distributed as needed.

 

 

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