NEW VOICES IN MEDICAL ILLUSTRATION

Through the keyhole KIRSTY McGEAREY

Introduction

Laparoscopic surgery is rapidly becom- ing a popular alternative to traditional operative procedures. If conducted safely. laparoscopic surgery offers sav- ings as a resuit of shorter hospital stays and a more rapid return to work. The oosmetjc benefits are obvious.

History

Laparoscopic visualization of the abdominal cavity was once restricted to one surgeon vie\*ing through the eyepiece of a laparoscope. In 1986 however, this problem was solved with the development of a charge-coupled device (CCD) 'TV camera attached to the laparoscope. allowing all members of the operating team to view simulta- neously. Thus hegan the era of video- guided surgery.

Video-guided surgery for most gen- eral surgeons rcyuires them to trust an image produced on a two-dimensional screen rather than their own three dimensional vision. I t requires them to re-adjust their. senses and develop hand-eyc co-ordination when viewing their movements on a monitor.

Traditionally the surgicai team com- prises a consultant, first assistant and a

nt. The role of camera i to a junior doctor. The

' tant is the eyes of the surgical team . . . he holds the laparo- \cope with thc camera attachment. A clear image of the operative field is imperative foI the eventual success of the operation.

Video-guided surgery at Frimley Park Hospital

Tr,uning lunior doctor\ to be camera ,is\i\tants I \ .I truitle\\ task - they rotate job\ ecuy months and 5ome are inherentlq hetter than others Con- \ultants often ,omplain that it is like

viewing the operation on a ship, refer- ring to the juggling up and down of the camera by the inexperienced junior doctor, indeed sea sickness is a docu- mented side effect experienced by surgeons with bad camera assistants. A difticult laparoscopic case may neces- sitate opening the patient if visual- ization of the operative field is poor.

A permanent camera assistant was thus required for the consultant at Frimley with the highest laparoscopic workload. The Department of Medical Illustration was asked to consider the job.

Job description

-The camera operator's role is to scrub and assist during laparoscopic proce- dures and help trouble-shoot any tech- nical problems with the camera sys- tem'.

In practice this has meant scrubbing up and assisting with 1-2 day case laparoscopic - cholecystectomies - a week. No troubleshooting or main- tenance has been necessary as the Day LJnit staff handle it all. Additionally, in the main theatre complex. one day a week is potentially devoted to laparo- scopic extravaganzas. i.e. up to 6 cholecystectomies and a laparoscopic fundoplication. Duties in the main theatres include cleaning and disinfect- ing equipment between cases and trou- bleshooting as well as scrubbing up.

Procedures

The list of procedures undertaken laparoscopically is endless, and includes laparoscopic cholecystect- omy. appendicectomy. fundoplication, hernia repair. liver biopsy. pelvic lym- phadenectomy. truncal and selective vagotom y.

In fact most operations that have ever been performed have also been tried laparoscopically - to the point of

the ridiculous, i.e. 23 hours long. At Frimley the two procedures the camera assistant is most involved with are laparoscopic cholecystectomies (removal of the gall bladder) and laparowopic fundoplications (treat- ment for gastrooesophageal reflux).

It is thought that 95% of patients needing a cholecystectomy are suitable for laparoscopic surgery, and there is indeed a backlog of patients for this procedure.

Operating room layout

The positioning of the surgeon, assis- tants, video monitors, anaesthetic equipment and other necessary machines is carefully planned.

Two video monitors are necessary so that the surgeon and camera assis- tant have an unobstructed view of the operative field.

Laparoscopic equipment and instrumentation

The sophisticated equipment necessary to perform laparoscopic surgery is very expensive. Unfortunately no industry standards apply to the manufacture of laparoscopic instruments.

lnsuffla tion

Visualization within the abdomen requires space in which to shine light and manoeuvre. In a standard opera- tion this space is created by opening the abdomen and allowing room light and air into the cavity. In laparoscopic procedures, this is accomplished by filling the peritoneal cavity with gas that distends the abdominal wall and provides an area for light and manip- ulation. Carbon dioxide is the standard gas used for this. The machine used to maintain the gas in the abdomen at an acceptable pressure is called an insuf- flator.

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New voices in medical illustration 29

Light source

The quality of light transmitted into the abdomen is extremely important for the accurate transmission of colour and intensity and to give a clear view of the abdominal cavity.

The development of fibre optics has moved both the light source and its controls to a separate and distant unit connected to the laparoscope with a light cord.

Video camera

Superb visualization of the operative fieid is essential to laparoscopic proce- dures. A one-chip end viewing camera with 450 lines per inch resolution is a minimum requirement for adequate imaging. Three-chip cameras provide a better quality picture.

The camera is a small unit attached to the laparoscope - a cable attaches this unit to a processor, transmitting the image to a video monitor, recorder and/or colour printer. The camera head is lightweight and easy to manipulate.

Most cameras have automatic aper- tures, all have focusing mechanisms and some also have a zoom lens. Newer models have controls mounted on the camera piece itself for trigger- ing a video recorder or printer. Auto- focus camera heads are also available. The latest Olympus OTV-S5 incorpor- ates a 114" CCD with horizontal resol- tion of more than 480 lines.

Video monitors

High resolution video-monitors are essential to take advantage of the current generation of video cameras for laparoscopic surgery. A standard medical grade monitor with a resolu- tion of 400 lines per inch matches the picture of a one-chip camera, whereas a high resolution monitor with 700 horizontal lines per inch takes better

advantage of the enhanced image of a three-chip camera.

Instruments

Very briefly, whilst the instruments themselves are more the concern of the scrub nurse and surgeon, they do have some relevance to the camera assistant.

Trocar and cannulas

Laparoscopic surgery requires the establishment of one or more ports of entry into the abdomen. Laparoscopic cannulas are introduced into the abdo- men with the aid of a sharp trocar. It is through these cannulas that all instru- ments and laparoscopes are passed.

Laparoscopes

Each rigid laparoscope is a unique optical instrument and laparoscopes designed with a variety of angled lenses and diameters.

The most commonly used lens for laparoscopic cholecystectomy is a lOmm 0" laparoscope. An endoscope with a 30-45" angled lens offers far more versatility in viewing the perito- neal cavity. It can be used to see around comers to visualize areas of the abdominal cavity not readily acces- sible from the straight-on approach. 70-80" telescopes are now also available.

Sterilization and disinfection

Most laparoscopic instruments can be safely sterilized using a steam auto- clave. Autoclavable laparoscopes are available but can be costly. However, laparoscopic cameras are damaged by heat and thus at Frimley, the laparo- scopes, camera attachment and light lead are all chemically disinfected using cidex. There is a suggestion that

laparoscopic cameras are also dam- aged by repeated exposure to chem- ical disinfectants - a sterile plastic bag can be used over the length of the camera and lead to maintain sterility and thus eliminate the need for chem- ical soaking.

Complications

The intensity of the light source can produce considerable heat at the end of the laparoscope and must be handled with care. Paper drapes and gowns can be singed, even the camera operator's gloves have been known to catch fire! A hot endoscope tip can also burn internal organs if there is prolonged contact within the peritoneal cavity.

A common problem encountered by laparoscopic surgeons is fogging of the distal lens after entering the abdominal cavity. This results from rapid changes in temperature and humidity. At Frim- ley the laparoscope is pre-heated in warm sterile water and a small amount of sterile anti-fogging solution is added to the end of the laparoscope.

The two-dimensional image pro- duced by current laparoscopic video systems results in a loss of depth perception for the surgeon - the most important factor in overcoming this is to provide continual visualization of the operating instruments on the video monitor. Co-ordination of the camera's movements with those of the surgeon is essential. Instruments inserted or manipulated within the peritoneal cavity without direct visual guidance may inadvertently injury abdominal structures.

Bibliography

Basic Surgical Skills: participant handbook, The Royal College of Surgeons of England, 19%.

Surgical Lapamcopy. Edited by Karl A. Zucker. Quality Medical Publishing, 1991.

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