Ann Thorac Surg 2004;78:2146-2149
© 2004 The Society of Thoracic Surgeons
New technology
Method and Value of Digital Recording of Operations for Congenital Heart Disease
Mazyar Kanani, MRCSa,*,
Ergin Kocyildirim, MDa,
Gordon Cohen, MDa,
Kieran Bentham, BAa,
Martin J. Elliott, MD, FRCSa
a The Cardiac Unit, Great Ormond Street Hospital for Children, London, United Kingdom
Accepted for publication October 8, 2003.
* Address reprint requests to Dr Kanani, The Cardiac Unit, Great Ormond Street Hospital for Children, London WC1N 3JH, UK
mazzykanani{at}hotmail.com
 |
Abstract
|
|---|
PURPOSE: We describe the methods we have used to employ digital video techniques in the teaching of surgery for congenital heart disease.
DESCRIPTION: This paper describes the hardware and software required to initiate and utilize digital video in surgery for congenital heart defects. Images are collected through a headlight camera and stored on standard digital-video camera tape. Tapes are catalogued using a purpose built database, linked to the hospital data system, and employing the European Pediatric Codes coding system for diagnostic and procedural coding. This permits keyword as well as patient-based searches. Master tapes are then digitally edited using proprietary software to create for example teaching tapes or to explain the operation to the family of the patient.
EVALUATION: Eighty percent of the procedures performed by one surgeon (M.J.E.) during the last year have been recorded in this way.
CONCLUSIONS: A working digital archive of pediatric cardiac surgical procedures has been created. Database links to hospital systems create the opportunity for linking full, visual records of procedures to be retained in an electronic patient record.
|
Introduction
|
|---|
There is no doubt that the morphology of congenital heart defects is difficult and time-consuming to learn. The terminology is complex; the visual representation of the morphology challenging, and there is often a mismatch between the morphologist's presentation of the defect and the surgeon's view in the operating room. Indeed, each specialist caring for the same child may have a different mental picture of the defect they are managing.
Against this background, we have been interested for many years in using video records of procedures for teaching and patient information. The advent of accessible and affordable digital technology has stimulated us to review our methodologies and to create a system, which ultimately will permit access to digital recordings of procedures as part of the electronic patient record (EPR). This paper describes the technology used, the editing techniques employed, the database and coding systems developed for indexing, and current methods of storage. Examples of use are given, and sample movies will be available on our relevant Websites.
Digital video recording has been achieved for more than 80% of the operations performed by one of us (M.J.E.) and his residents during the last year. Operations that were not recorded were those in which the family declined permission; the child was too large or the operation field too great (the magnification of the field to x2.5 to match the surgeon's loupes makes it impossible to record adequate quality film if the surgeon is not wearing them); the camera had been set up wrongly, usually too far off-center; or the camera was not available. Satisfactory images have been obtained in 90% of cases. We believe that with greater attention to the detail of camera position in the operating room, this number can be increased to close to 100%. All tapes have been catalogued successfully, and a number of compilation tapes are now in production.
Edited movie clips are now being linked with clips of pathologic specimens (Prof R. H. Anderson and Dr Andrew Cook, funded by the British Heart Foundation), to create a phenotype library, which will ultimately be accessible on the Web by authorized users. We have not kept records of how many families want to see the operation tapes; however, it is our estimate that about 25% of them are interested and that this number is rising as word gets around.
|
Method of Image Capture
|
|---|
All digital video is obtained with a Karl Storz headlight camera (Endovision Headcam Model 202720 30 PAL; Karl Storz, Tuttlingen, Germany). The lens of the system matches the field of view provided by the most common loupe magnification used in our institution, x2.5. This means that what is seen on the television monitors is almost exactly the same as the view of the surgeon. The signal from the headlight camera is transferred to the image processor, and hence to a digital video camera (DVCAM) recorder (SONY DSR-25; Sony Electronics, Park Ridge, NJ). The output from that device passes to a color TV monitor (SONY x 21 inch, model PVM 2130QM; Sony Electronics) placed behind the operating surgeon so that the assistants can see easily what the surgeon sees. An output signal from the TV monitor is passed to a local switching and distribution system, which allows the image to be sent to other monitors in the operating room, and thence through a studio distribution system in the hospital audiovisual department to all selected lecture rooms in the institution. Figure 1 demonstrates the arrangements of the devices and connections.
View larger version (39K):
[in this window]
[in a new window]
|
Fig 1. The camera set-up connecting the operating room (OR) to the rest of the department. (AV = audio visual; CPB = cardiopulmonary bypass; DV = digital video.)
|
|
Optimal image quality is obtained by careful attention to detail. Particularly important are initial adjustment of camera position, accurate white balancing of the camera, reduction of head movement to a minimum (we have noticed that the wearing of a headlight camera is a useful method of improving surgical technique of residents), and the desire of all the team to keep the image in the center of the TV screen by moving the camera during the operation if it becomes displaced.
|
Tape Archiving
|
|---|
The images are recorded onto commercial DVCAM 3-hour tape, which is labeled with the patient's details, the date of operation, the surgeon's name, and a brief description of the procedure (eg, repair of atrioventricular septal defect). More than one operation can be recorded on one tape. If the primary operating surgeon is not opening the chest or not closing, these portions of the operation are not recorded, as setting up the camera for optimum recording takes a few moments.
After the tape is full, it is taken from the operating room and catalogued. Each tape is given a sequential tape number and logged into the video archive database designed in Microsoft Access by two of us (M.J.E. and K.B.). In accordance with our departmental policy, the database is linked to the hospital Patient Information Management System (PIMS [developed by iSoft, Manchester, UK]). All diagnoses and operations are coded using the European Pediatric Codes (EPC).[1] The diagnostic codes are imported and validated, from other modules of the departmental database. The type of operation note is also accessible within the database through a URL address in the relevant field. That provides for review of the operation details without leaving the database, and is an extremely useful feature when reviewing tapes some time after the operation.
|
Video Editing
|
|---|
All master tapes are catalogued and stored. The tapes can, if desired, be edited for a number of purposes. Single-frame sampling can be done to demonstrate defects and repair or for transfer to conventional Microsoft PowerPoint or Apple Keynote case presentations. Short segment editing is done for similar purposes, but using movie clips. A "summary" tape can be created of a particular patient's operation for detailed case review (eg, mortality and morbidity conferences), or for showing the family the operation. All head movement and unnecessary portions can be edited out. The movie can be transferred to other media such as minidigital video (DV) tapes, VHS tape, compact disk (CD), or digital videodisk (DVD), as desired. Compilation tapes can be created for teaching. Good examples include coronary artery variations and their management in the arterial switch procedure, or the varying morphology and modes of repair of ventricular septal defects. These tapes are also catalogued and stored. Finally, copies can be created to be kept by surgical residents for later review or monitoring of their own technical performance.
Over the last 2 years we have utilized a number of software editing packages before settling on our current solution. One of the primary constraints on choice of software was a desire to present video clips inside Microsoft PowerPoint presentations, as all of us have heavy international presentation commitments.
Originally, we used an entirely IBM PC-based system using Adobe Premiere 6.0 as our editing software. This system is very easy to use, and the editing software is easy to teach. However, we have experienced innumerable problems in compressing the edited video into a form acceptable to PowerPoint. Various Codecs have been tried, but the quality of video replay in PowerPoint has been disappointing. While we do still use the excellent Adobe Premiere to edit on our personal computers, we have now converted to an Apple Macintosh-based system and have noticed greatly improved video handling and PowerPoint compatibility. The original DV tape is linked by a 4-pin to 6-pin Firewire cable (through a Firewire hub) to an Apple G4 computer running parallel 1Ghz processors and 1GB video random-access memory (RAM). For simple editing and single frame capture, we use the preinstalled "iMovie" software. This is a very intuitive product, and all our residents learn how to use it in a very short time. For more sophisticated editing, and particularly in the creation of compilation tapes, we use Apple Macintosh "Final Cut Pro 4." All clips are logged, and batch capture is used to shorten the edit period. Good clip logging and labeling, combined with appropriate archiving of master tapes, reduces the hard disk storage demands of the service. We can add labeling, various effects, create transitions between clips, and add a sound track at this stage in the process.
Sound is recorded separately from the video using a Sony MD minidisk and Trantec S3.2 stereo clip microphone. Recording can take place in the operating room or at the editing stage to give maximum flexibility in video production.
Once the edits are complete, the movie created can be exported either back to the DV recorder through Firewire; stored uncompressed to a remote hard disk (we use a Fire wire-chained series of LaCie 200Gb disks for this purpose, one of which also functions as a scratch disk); or compressed to varying degrees for transfer to PowerPoint, CD, DVD, or the Web. It is in this phase of the process that the Apple-based system has proved clearly superior because of the speed and quality offered by QuickTime-based compression. The movie can, of course, be exported in any format readable by commercially available, and usually downloadable, Codecs.
|
Acknowledgments
|
|---|
This work is supported by the Richard Hall fund and by the British Heart Foundation (Dr Kanani).
|
Footnotes
|
|---|
Research at the Institute of Child Health and Great Ormond Street Hospital for Children NHS Trust benefits from Research and Development funding received from the NHS Executive. The technology described herein was also supported by a grant from the British Heart Foundation (MK), and the equipment purchased by donations from the Richard Hall Fund and San Scoria Society. The authors were in full control of the design of the system, methods used, outcome parameters, analysis of the data, and the production of the subsequent written report.
|
References
|
|---|
- Association for Paediatric Cardiology. The European paediatric cardiac code: the first revision. Cardiol Young 2002;12(Suppl 2):1–212
Related Article
-
INVITED COMMENTARY
- Jeffrey P. Gold
Ann. Thorac. Surg. 2004 78: 2149.
[Extract]
[Full Text]
[PDF]
Top
Abstract
Introduction
