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Laparoscopic instruments
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摘要
The description of laparoscopic instruments covers all aspects of laparoscopic instruments in the operating room.
The technical key steps of the chapter are presented in a step by step way: structure/function, ideal requirements, basic instruments, trocars, advantages and disadvantages, ergonomics, suction-irrigation, clips and staples, complications.
The technical key steps of the chapter are presented in a step by step way: structure/function, ideal requirements, basic instruments, trocars, advantages and disadvantages, ergonomics, suction-irrigation, clips and staples, complications.
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媒體類型
 刊物
2005-07
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普通的
最愛
 音訊
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數位出版
WeBSurg.com, Jul 2005;5(07).
URL: http://www.websurg.com/doi-ot02en320.htm
URL: http://www.websurg.com/doi-ot02en320.htm
Laparoscopic instruments
1. Introduction
Each surgical specialty has different requirements that have led manufacturers to propose a range of instruments adapted to each specialty. Instruments vary in diameter from 1.8 to 12 mm but the majority of instruments are designed to pass through 5 or 10 mm trocars. Instrument lengths vary from 18 to 45 cm. Many laparoscopic instruments are available in both reusable and disposable versions. Most reusable instruments can be partially or totally dismantled for maintenance and washing. Some manufacturers have produced modular systems where parts of the instrument can be changed to suit the surgeon (i.e.: different handles or working tips).2. Structure/function
• Diameter/length
• Generalities
The diameter of laparoscopic instruments ranges from 1.8 to 12 mm. These diameters provide instruments of varied degrees of rigidity and are adapted for different situations. The longer and thinner the instruments are, the more flexible they are. The thinnest instruments exist only in shorter lengths and certain instrument types are not available in the thinnest diameters.These instruments have been designed to offer a full range of surgical functions (i.e.: clamping, grasping, dissecting and cutting). Thus the tips of laparoscopic instruments reflect those found in open surgery.
• Diameters and lengths
Diameter 1.8 to 2 mm:Blunt, fenestrated and toothed graspers are available, as well as suction-irrigation tubes. In these needlescopic sizes, there are no dissecting hooks.
Diameter 3 to 3.5 mm:
Most standard 5 mm instruments are also available in these sizes. They permit smaller incisions in routinely performed laparoscopic procedures (gallbladder, anti-reflux) or more occasional ones (endocrine, cervical procedures). However, they are more fragile and have less shaft rigidity than the 5 mm versions. In 2002, no bipolar graspers adapted to these diameters were available.
Diameter 5 mm:
This is the most common diameter for laparoscopic instruments, most of which are available in this size (i.e.; all types of graspers, scissors, hooks, bipolar graspers and articulated or angulated instruments).
Diameter 10 to 12 mm:
Apart from the endoscope, most 12 mm instruments are either used for retraction or exposure, or contain an integrated mechanism (clip applier, linear stapler, etc.).
• Instrument lengths
Standard instruments range from 34 to 37 cm long, depending on the manufacturer. This length can be used to perform most surgical procedures. Shorter instruments (18 to 25 cm) are adapted for cervical and pediatric surgery. Certain procedures for adults can also be performed with these shorter instruments (gallbladder, anti-reflux), but their use necessarily leads to a change in insertion position and an adaptation of the operating technique.45 cm instruments: these particularly long instruments have been adapted for procedures on obese or very tall patients. However, their use is becoming increasingly common due to the rise in procedures being performed on obese patients.
• Degrees of freedom
Most laparoscopic instruments, i.e. graspers and scissors, have basic opening and closing functions. Many instruments manufactured during the past few years are able to rotate 360 degrees, which increases the degrees of freedom of movement of the instrument. However, many of these instruments are designed to prevent rotation when the instrument is tightly closed (e.g.; during tissue clamping). This may facilitate tissue retraction but can be a disadvantage if the surgeon wishes to rotate the grasped tissue.A certain number of instruments offer angulation at their tip, in addition to the usual 4 degrees of freedom. These instruments are used to avoid obstacles and for lateral grasping when the instrument is placed outside of the visual field. Angulation features are available both for reusable and disposable instruments. However, the complex mechanisms of such instruments make sterilization very difficult, so manufacturers tend to offer a larger range of disposable versions of these instruments.
• Articulated systems
A variety of instruments, especially retractors have been developed with multiple articulations along the shaft. When these are fixed with a tightened cable, the instrument assumes a rigid shape, which could not have been introduced through a trocar. However, the manufacture of these products is laborious and few instruments are available.• Sterilization and cleaning
The sterilization of surgical instruments must comply with safety standards. These vary depending upon the legislation of individual countries each of which may which require different sterilization systems and sterilization times. For example: - Germany: sterilization for prion (Creutzfeld-Jakob Disease) is required by law. For this reason, German legislation requires steam autoclaving at 134°C for 5 minutes.
- France: French legislation requires sterilization for prion by steam autoclaving at 134°C for 18 minutes.
- American legislation: AAMI TIR No. 12 – 1994: Designing, testing, and labeling reusable medical devices for reprocessing in Health Care Facilities: A Guide for Medical Device Manufacturers. This document is the primary one referred to by the Food and Drug Administration (FDA) for sterilization validation and criteria regarding sterilization of reusable devices.
ANSI/AAMI/ISO 14937:2000: Sterilization of health care products - General Requirements for Characterization of a Sterilizing Agent and the Development, Validation, and Routine Control of a Sterilization Process for Medical devices.
ANSI/AAMI ST81:2004: Sterilization of Medical Devices - Information to be Provided by the manufacturer for the Processing of Resterilizable Medical Devices (This is the same, with some minor exceptions as BS EN ISO 17664: 2004 Sterilization of Medical Devices - Information to be Provided by the Manufacturer for the Processing of Resterilizable Medical Devices).
AAMI is the American Association of Medical Instrumentation. ANSI is the American National Standards Institute.
Among the numerous sterilization systems are the following:
- ethylene oxide;
- steam autoclave;
- hydrogen peroxide.
Cleaning
Instruments require cleaning systems that are adapted to the way they are designed. Some instruments can be dismantled and each piece can be cleaned independently. Other instruments cannot be dismantled but are equipped with a flush port. The flush port requires abundant rinsing (300 cc) under pressure at the end of each usage. Incomplete cleaning followed by a high temperature autoclave sterilization will cause coagulation of proteins in the flush port channels and articulations leading to malfunction.
• Disposable instruments
The process of cleaning, disinfection and sterilization is time-consuming and requires specialized equipment and personnel. Disposable instruments avoid such necessities. Disposable instruments must never be reused:- Disposable instruments are not designed to be cleaned: biological fluids infiltrate into the mechanisms, which can never be properly washed. Sterilization will not destroy all microorganisms within heavily contaminated instruments.
- Disposable instruments use materials, which are not designed for high temperature autoclaving. Heat can damage the mechanical components of these instruments (melting of plastics, blockage of joints, dysfunction of safety system, etc.) making them malfunction and unsafe.
- For instruments that were sterilized with Gamma rays, certain sterilization processes (e.g. ethylene oxide sterilization) will cause toxic residues to be freed.
3. Ideal requirements
Laparoscopic equipment should be presented in trays specifically intended for this use. A “basic” tray for laparoscopic abdominal procedures contains a number of conventional instruments along with laparoscopic instruments.Conventional instruments:
Certain conventional instruments are needed to establish the pneumoperitoneum using the open approach (technique described by Hasson and recommended today) and to close the trocar wounds at the end of the procedure. This tray contains:
- scalpel;
- forceps;
- retractors;
- needle-holder;
- pair of scissors.
“Basic” laparoscopic instruments:
Most routine laparoscopic procedures can be performed with grasping and dissecting instruments. Each surgical technique has its own specific needs that are detailed in the WebSurg operating technique chapters.
“Basic” instruments may include:
- fenestrated grasper;
- blunt grasper;
- hook;
- pair of coagulating scissors;
- needle-holder;
- suction and irrigation system.
4. Basic instruments
• Scissors
“Operating instruments” refer to the instruments that are used to perform the procedure itself. Certain operating instruments can also be “retracting instruments” or “exposing instruments”. This is the case for certain graspers.Scissors have all of the instrument characteristics described in section 2: Structure and function. Scissors measuring from 1.8 to 12 mm in diameter can be found on the market. Certain features make scissors better adapted for specific functions.
The following types of scissors are available:
- straight scissors;
- curved scissors;
- short blade;
- mid-sized blade;
- long blade;
- insulated scissors for monopolar coagulation;
- non-insulated scissors;
- angulated scissors.
• Hooks
Hooks are usually relatively simple instruments, whose distal tips can vary slightly. They must be insulated along their entire length, as they are used with monopolar coagulation. Certain manufacturers make hooks with a ceramic cone protecting the distal end. The cone avoids alteration of the plastic and protects very efficiently against current diffusion.• Graspers
• Tips
The graspers available are either used for holding or dissecting tissues. Numerous variants exist. They can be distinguished by the form of their tips: - sharp grasper;
- blunt grasper;
- curved grasper;
- fenestrated grasper: although such graspers are not common in open surgery, they have become very popular in laparoscopy because they allow a secure and atraumatic handling of tissues, particularly the bowel.
• Jaws
In addition to the choice of tips, the jaws of the grasper can be found with different surface properties, depending on the intended use: - deeply serrated for powerful grasping;
- finely serrated for atraumatic grasping;
- tungsten coating for precision work.
• Dissectors
Many instruments can be used to dissect tissues. Most of the time, the surgeon operates in conditions similar to conventional open surgery and uses scissors or graspers to dissect. In some cases, hooks can also be used to dissect tissues.
In certain procedures, “hydro-dissection” is used to facilitate location of the dissection planes before opening them.
• Needle-holders
Needle-holders for laparoscopic surgery have to be particularly resilient in order to produce a firm grip of the needle despite it being around 35 cm from the surgeon’s grasp. For this reason and until now, no disposable needle-holders are available on the market. Needle-holder jaws: most needle-holders have a jaw with a flat grasping surface. This makes it possible to turn the needle in all directions, as in conventional surgery. Certain needle-holders have jaws with a dome-shaped indentation at their tip, which automatically orientates the needle in a perpendicular direction. Although this function is not always useful, it can sometimes make it easier to grasp the needle.
5. Trocars
• Common components
• Sleeve
Disposable and reusable trocars share the following common components:Sleeve:
This is the working channel. Its outer and inner dimensions differ by the thickness of the material with which it is made. The size of the channel differs depending on the manufacturer. For 5 mm trocars, the diameter of the inner channels varies between 4.5 and 5.5 mm. It is important to know the exact size of the inner channel. If the diameter of the channel is too large for the instrument used in a trocar with no valve, gas leaks can occur. If the diameter of the channel corresponds exactly to the size of a needle-holder, the thread and needle-holder cannot pass through the channel at the same time. A 5 mm needle holder requires an inner channel of 5.5 mm, to allow the thread and needle-holder to pass through together. The outer diameter is also a constraint, as it will determine the size of the incision. Ideally the sleeve should be thin-walled so that inner and outer diameters are similar.
• Tip
The trocar tip facilitates entry through the abdominal wall into the peritoneal cavity. Different types of tips are available: conical, blunt, pyramidal, etc. Sharp tips cut an entry path through the abdominal wall while blunt tips stretch the tissues apart to gain access to the abdominal cavity. The choice of these tips often depends on the surgeon’s training.
• Sealing system
The gas pressure of an established pneumoperitoneum is above the surrounding atmospheric pressure. In order to prevent gas leaking from the port sites, the trocar incorporates a valve. This allows the insertion of instruments without the escape of gas. Different valve systems exist including flap valves, piston (trumpet) valves, duckbill valves and magnetic ball valves.• Insufflation port
Many trocars are equipped with a port that allows for the insufflation of gas into the operative cavity. Some trocars do not have this port, notably trocars <= 5 mm in diameter.• Reusable trocars
At the beginning of surgical video-laparoscopy (1987-1990), most trocars used were reusable trocars. These trocars were composed of numerous dismantable parts that are screwed together. Some had an insulated sheath for use with electrosurgery. These trocars have the advantage of a reduced operational cost, but cleaning and sterilization involve laborious dismantling and reassembling, which inevitably leads to damage of the mechanical parts. The high costs of cleaning and sterilization and the reduced reliability of these trocars has led many surgeons to switch to disposable equipment.• Disposable trocars
• Airtightness
Disposable trocars are costly when multiple laparoscopic acts are performed, but they have many advantages compared to reusable instruments:- Savings in human resources, as no maintenance is required.
- Available in multiple sizes and diameters, from 2 to over 30 mm to accommodate circular staplers for anastomosis.
- Airtight seal valves that fit 2 to 12 mm instruments without modification or the need to add an adapter.
• Other types
Most disposable trocars with cutting tips have a safety system, which covers the point or blade as soon as it enters the abdominal cavity, thereby minimizing the risk of organic injury. Transparency of certain trocar sleeves enables visualization of the structures surrounding the trocar (e.g. abdominal wall). This helps to correctly position the tip of the trocar, which remains within the abdominal cavity. It also increases the field of view allowing the identification of structures or instruments that would otherwise not be visible.
• Fixation systems
• Principles
Ideally, a trocar should be firmly held in the abdominal wall to reduce the risk of it slipping out of the peritoneal cavity. Certain manufacturers have developed textures on the outer surface of the trocar that help it to grip the abdominal wall. There are also various systems for fixing the trocar to the abdominal wall. This is particularly useful when the pneumoperitoneum has been established by the open approach and the entry site is large providing little grip for the trocar.• Internal balloon
Internal balloon and external compression:This trocar system is used to create an airtight seal after inserting the trocar via open laparoscopy. The trocar is equipped with an inflatable balloon at its tip. The balloon is inflated after introducing the trocar into the abdominal cavity and then is pulled back against the abdominal wall. External compression is achieved with a foam ring that presses against the opening and locks to the trocar.
• Screw threads
Many systems use screw threads to minimize or eliminate the chances of trocars slipping out of a puncture site. The groove of the thread should correspond to the exact diameter of the incision so that the crest of the thread bites into tissue, preventing the trocar from slipping. Two systems exist:- The trocar sleeve itself is threaded.
- Threaded collars that can be fixed onto smooth trocar sleeves. This system has the advantage of allowing easy adjustment of trocar position.
• Purse-string fixation
If a trocar inadvertently comes out of the abdomen, a purse string suture can be placed around the entry site. It can also be fixed to a protruding part of the trocar (e.g. stopcock) to prevent slippage.Internal fanlike system:
This is built into the end of the trocar.
6. Advantages and disadvantages
The choice of disposable and/or reusable instruments depends on local health policies, and on limitations of sterilization and human resources.In developing countries, disposable instruments are very rarely used because labor costs are low compared to the cost of disposable instruments.
In countries where sterilization procedures are more demanding (Europe, USA), surgeons often choose to use disposable equipment in order to save on high labor costs.
During most laparoscopic procedures, a combination of both disposable and reusable instruments is commonly used.
Recommended disposable equipment:
- gas connection system;
- trocars;
- scissors (in cases of extensive dissection with application of electrosurgery the blade is rapidly blunted making reuse inadvisable);
- rarely used specialist instruments;
- use of clip and stapling systems when numerous clips or staples are required.
Reusable equipment:
A laparoscopic set is made up of a certain number of instruments. For instruments that are used frequently, and whose cost is high in their disposable version, a reusable version is recommended:
- coagulation hooks;
- graspers;
- needle-holders;
- scissors for exceptional use.
These instruments can be easily cleaned and sterilized in an autoclave, and are therefore reusable.
7. Ergonomics
• Handles
• Conventional ringed 1
The ergonomics of instrument design differ with each surgical application. Different surgeons will have specific preferences, which reflect their specialty and training. A surgeon should carefully test a range of instruments until he/she finds a design that he/she is comfortable with and which suits his/her purposes.Conventional ringed handles:
These instruments comport a handle, which is based upon the classic ring handle found on most scissors and tissue forceps used in open surgery. Handles can be found that are directed 90 degrees in relation to the working axis while others run parallel to the working axis. Other handles can be found between these two extremes.
• Conventional ringed 2
Different manufacturers have designed rings for the surgeons’ fingers of different shapes and sizes. Some are designed to accept one finger, others two or more fingers. Some rings feature prongs upon which the surgeon can rest other fingers.• Cylindrical handles
For systems that do not have an articulating function (hook, suction-irrigation system), the handle generally conforms to a cylinder. This may be very simple (hook rod with no particular handle) or complex (thickened and fluted hook handle). The cylindrical handle of suction-irrigation devices incorporates a valve or piston system for controlling the irrigation or suction. Several manufacturers offer needle-holders with handles in the instrument axis. When the needle-holder is closed, the handle forms into a cylinder making it easy to manipulate.• Other handles
• Adaptable-dismantable
Instruments have different elements that can be adapted to fit the needs of the surgeon. For example, some graspers can accommodate both straight and 90° angulated handles. This increases the available options, without increasing the number of instruments in the operating room. Operating teams need to know their instruments perfectly, and must therefore use them regularly.• Locking system
Certain instruments have been designed to allow locking of the jaw. This can be very useful when a tissue needs to be grasped firmly for long periods of time since it prevents the surgeon’s hand from becoming fatigued. The locking mechanism is usually incorporated into the handle so that the surgeon can easily lock or release the jaws. These systems usually comport a ratchet so that the jaws can be closed to different positions and to different pressures.• Electrical connection
Most instruments, whether disposable or reusable, are designed for use with monopolar surgery. They are equipped with a plug to connect them to the monopolar cautery. The plug should be positioned ergonomically. In some cases, it is placed on the handle, which can hinder the surgeon’s movements.• Articulated jaws
Single versus double action jaws:There are various technological solutions for obtaining articulated jaws. The two main systems are:
- Forceps with one fixed jaw and one articulated jaw;
- Forceps where both jaws are articulated.
Single action jaws open less than double action jaws but close with greater force making them ideally suited for firmly grasping a needle. Thus most suturing instruments have a single action jaw while dissecting instruments where a wider opening is advantageous have a dual action jaw.
The systems used to assemble and dismantle the instruments can also vary, resulting in a change in cleaning procedures.
• Position patient-surgeon
• 1
Position of the patient and the surgeon:To perform an operation safely and successfully, it is important for the surgeon to be in the most ergonomic position possible. Generally, three factors are involved: the targeted organ, the positions of the trocars and the position of the patient.
• 2
The position of the surgeon, the surgical maneuver being performed and the position of the patient will influence the ergonomics of the instruments. For example, an instrument whose handle is directed 90° downward will not enable a surgeon to operate on the epigastric area while in a sitting position between the patient’s legs. • 3
Basic positioning will depend upon how a surgeon has been trained to perform a specific procedure. However, the surgeon must be prepared to adapt according to the anatomical characteristics of the patient. In the following situations these solutions are proposed:- Patient supine: if the surgeon and assistant stand on opposite sides of the patient then two video monitors are needed, one on each side of the patient, in order to provide optimal viewing conditions for both surgeons.
• 4
- Position of surgeons for pelvic surgery: the surgeon may need to work on both the left and right of the patient. If the procedure is limited to the median pelvis area, one screen, situated between the patient’s feet, may be sufficient. • 5
- Procedure in the epigastric area or in the flanks: the surgeon may be positioned on the patient’s side (cholecystectomy – American position) or between the patient’s legs (cholecystectomy – European position). • Surgeon position
Here again, the choice in positions will depend on the surgeon’s personal preference.The surgeon should work in the most comfortable and least tiring position possible:
- shoulders relaxed;
- arms alongside the body;
- elbow at a 90° angle;
- forearm horizontal (between 70° and 90° in relation to the floor);
- hands and fingers supple on the handles (importance of finding the most suitable handle);
- sitting or standing: depends on the surgeon’s preferences and sometimes on the type of procedure and the instruments used.
Non-compliance with these principles can result in pain to the surgeon’s neck, shoulders, forearms and fingers, and can sometimes lead to paresthesia, or even hypoesthesia, of the thumb.
8. Suction-irrigation
Irrigation:The rapid availability of a suction system is essential during all laparoscopic cases. Irrigation is not always necessary but most modern systems combine suction and irrigation. Irrigation is essentially used in three applications:
- extensive lavage for generalized, acute infections;
- rinsing of the biliary tract in common bile duct surgery;
- hydro-dissection.
Several irrigation systems are available.
Pressure bag:
A standard IV giving set bag usually containing normal saline is placed within a pressure cuff. The bag is then pressurized. Irrigant can then be flushed into the operative field via the suction-irrigation instrument. The flow is controlled by a valve on the instrument handle. This type of system is not powerful enough for hydro-dissection, and cannot inject large quantities of fluid into the peritoneal cavity for an efficient lavage.
Compressed air system:
This system uses the principle of the vacuum pump. They are disposable systems that are hooked up to the operating room compressed air system. A pressure transfer system uses the hyperpressure of the compressed air to pressurize the irrigation fluid. These relatively inexpensive, disposable systems enable surgeons to have high pressure irrigation at all times.
Roller pump:
This requires disposable tubing inserted between the wheels of the roller pump. The variable speed of the pump allows adjustment to the rate of flow of the irrigant.
Independent electric motor system:
This disposable system is composed of an electric pump that generates the pressurization of the irrigant.
Dangers:
The use of high flow, high pressure irrigation systems during laparoscopy involves the risk of significantly increasing the intra-abdominal pressure. The most powerful irrigation systems can inject several liters of fluid per minute into the abdomen. This volume will increase the intra-abdominal pressure accordingly. It is mandatory to arrange for systematic evacuation of the pneumoperitoneum or to work with an insufflator equipped with an automatic exsufflation system capable of preventing excessive pressure.
Suction:
The shaft of the suction instrument may be disposable or reusable. At the tip of the instrument there is either a single suction hole or multiple perforations.
Single opening:
Tubes with a single opening are recommended for injections of fluid under pressure and for very localized suction.
Multiple perforations:
These are recommended for suction-irrigation involving a large quantity of fluid dispersed within the abdomen. In this case, the chance of the suction holes of the instrument being blocked by soft tissues such as the omentum is reduced.
9. Clips and staples
• Clips
Manufacturers provide a large variety of clips. They measure from 5 to 10 mm, are made of absorbable or non-absorbable (non-magnetic) materials, and are applied with disposable or rechargeable systems.Clip systems can be used to ligate vessels or ducts ranging from less than 1 mm up to 8 mm. Beyond 8 mm, there is a risk that the clip is insufficiently large to completely occlude the vessel or duct resulting in a leak (bleeding, biliary leak, etc.).
• Staples
• 1
Both articulated and non-articulated stapling devices are available that can perform linear stapling combined with a linear transection. These stapling devices allow the application of a line of staples ranging in length from 30 to 60 mm, and with penetration depths ranging from 1.5 to 2.5 mm. Some instruments are designed with distal articulation allowing stapling and division in a different axis (up to 45°) to that of the trocar. This option is particularly useful in pelvic surgery.Most systems used in laparoscopy apply six rows of staples, allowing for division between these six rows of staples. These systems are used to:
- divide tissues (lungs, liver, mesentery);
- control veins (renal, adrenal, hepatic veins, etc.);
- control arteries (hepatic, renal, inferior mesenteric arteries, etc.);
- divide the digestive tract (small bowel, colon, rectum);
- perform intestinal anastomoses.
• 2
Circular stapling devices of varying diameters are designed for intraluminal anastomoses of the digestive tract. They are comprised of two rows of staples, in addition to a blade for dividing the tissues to restore continuity of the digestive lumen.The staples used in these devices are made of non-absorbable and non-magnetic titanium.
10. Complications
Complications related to the use of laparoscopic equipment are numerous and varied.Surgeons must understand and look out for two types of complications in order to remedy them rapidly:
- Problem of electrical insulation: the use of monopolar current through instruments such as hooks, graspers and scissors requires that these instruments have perfectly insulated sheaths. Repeated cleaning and sterilization can lead to insulation damage allowing current to leakage. If the current comes into contact with neighboring tissues, severe burns can occur. It is essential to ensure that the instrument is perfectly insulated at the beginning of each procedure.
- Instrument breakage: repeated exposure to high pressure and high temperature sterilization can degrade the mechanisms of the instrument. Channels within the instrument may become obstructed by organic and protein wastes that coagulate during sterilization. Finally, the considerable mechanical strains applied on the instruments’ articulations can cause these to break. If mechanical parts get lost in the operative cavities then they must be retrieved.
11. Conclusions
Endoscopic and laparoscopic surgical instruments are extremely varied. An increasing number of instruments are being designed for specific applications. Instruments have become increasingly complex, with greater functionality and freedoms of movement. Such instruments reflect the trend towards automation of procedures. In the future, such developments might ultimately lead to full robotization.