48. Ergonomics in Laparoscopic Surgery
Ramon Berguer, M.D.
As surgeons, we use tools to carry out our trade. How well—or awkwardly—
we work with these tools has a sizable impact on the length of the procedure and the overall morbidity. The “relationship” between the surgeon and their tools also determines how much effort is expended by the surgeon. Ergonomics (often called human factors in the United States) is the study of the psychologic and physical interaction between the user (e.g., surgeons, assistants, or nurse) and their tools [12]. Because the costs of surgical errors and delays are substantial in both economic and human terms, ergonomic principles should be applied in the operating room (OR) to make the best possible use of our surgical tools.
A. Ergonomics and Laparoscopic Surgery
In open surgery, we look at and touch the patient’s tissues directly using our hands or relatively simple instruments. In this situation, our senses of vision, touch, and position are working under normal conditions and with a large per- formance reserve so that standard surgical instruments, although not perfect, serve us well. During laparoscopic surgery, the situation is very different [11].
The surgeon indirectly views the operative field and can only touch the intraab- dominal tissues with long instruments via ports that are in fixed positions. Our senses are now working much harder to achieve the same goals. The proper design of the instruments and the layout of the operating room now become crit- ical to avoid fatigue and human errors. In other words, because simple tasks are more stressful and fatiguing during laparoscopic surgery, we have less physical and mental reserve to compensate for the poor design of instruments or the poor layout of the OR environment [1] (Figure 48.1). This is why ergonomics is important.
B. Critical Ergonomic Adjustments for Laparoscopic Surgery
The goal of proper posture is comfort, efficiency of movement, and mini- mization of the risk of musculoskeletal injuries to the operator. The surgeon’s neck and back should be maintained in a comfortable and upright position facing
forward. During laparoscopic surgery, the ability to achieve this ideal posture is determined by:
1. The height of the operating room table
2. The position of the visual display (e.g., monitor) 3. Foot pedal locations
4. The selection of hand instruments
Although back posture tends to be straighter in laparoscopic surgery (because the surgeon no longer has to bend and twist to look directly inside the patient), more than 15% of surgeons still report frequent back pain and stiffness following laparoscopic operations [2]. These symptoms are likely due to the adoption of a more static posture (standing stiffly without moving) [3], which is the result of increased concentration and the frequent need to look in one direc- tion at the monitor while manipulating instruments or foot pedals in another direction.
Although individual adjustment in the layout of the OR (patient and monitor position) can decrease this problem, it is always beneficial to periodically relax your mind and body, move around, look away from the monitor, and let go of the instruments. We unconsciously take these “minibreaks” during open surgery but often forget them during laparoscopic operations, which are more
“intense.”
Ergonomic celling physical and mental reserve
Open surgery Laparoscopic surgery
Figure 48.1. The surgeon’s mental and physical reserve during laparoscopic surgery is significantly reduced compared to open surgery.
C. Operating Table Height
The proper adjustment of the operating table height is very important in laparoscopic surgery. Ergonomically, the angle between the lower and upper arm should be between 90° and 120° when performing manual work [4, 15]. The operating table should be elevated or lowered such that the surgeon will be able to work within this ideal “window.”
1. Specifically, in regard to setting the table position for laparoscopic operations, the table’s height should be adjusted so that laparoscopic instrument handles (after the instruments have been inserted into the ports) are roughly at, or slightly below, the level of the surgeon’s elbows.
2. Because laparoscopic instruments are much longer than their open counterparts, this requires lowering the table substantially. This may be difficult in some cases, and you many need to stand on one or more lifts to achieve the proper table height.
D. Foot Pedals
Foot pedals are commonly used during laparoscopic surgery to activate instruments such as the cautery, ultrasonic shears, bipolar device, or other tissue welding/dividing instruments. Foot pedals, which are often poorly positioned, demand awkward and unnatural postures and should be avoided in favor of hand controls when possible.
1. Pedals should be placed near the foot and aligned in the same direc- tion as the instruments, toward the target quadrant and the principal laparoscopic monitor. Such positioning will permit the surgeon to activate the pedal without twisting their body or leg. If the surgeon is standing on a lifting platform, the pedal must be placed at the same level off the ground.
2. A pedal with a built-in foot rest is preferable so the surgeon does not have to hold their foot in the air or move it back and forth on the floor.
If there are two pedals (for different devices), the surgeon must be careful not to confuse them in the darkness.
E. Vertical Positioning of Video Monitor
Because the surgeon views the surgical field through a visual display (e.g., video monitor) for lengthy periods during laparoscopic surgery, the position of the video monitor will affect neck and back posture.
1. The display should be placed directly in front of the surgeon, 15°–40°C below eye level for maximum comfort [9, 14].
2. Although standard video monitors still provide the best picture quality, the quality of the image of flat panel screens, displays suspended from
booms, and head-mounted displays is improving. These alternative display devices are now acceptable alternatives to the standard video monitor.
3. Video display devices that are mounted on flexible booms allow the surgeon to alter the vertical position of the monitor to obtain the ideal angle between eye level and the monitor, as described above (Figure 48.2).
F. Choosing Laparoscopic Instruments
1. Laparoscopic instruments are lengthy because they must reach inside the inflated but closed abdomen. Unlike open surgery, the surgeon works a considerable distance from the target organ. The instruments are passed through narrow ports that are in fixed positions. Given these restrictions, it is not surprising that these instruments are more awkward and difficult to use than open instruments. Various attributes of the laparoscopic instruments account for their handling character- istics, including decreased mechanical efficiency, increased length, movement about a fulcrum on the body wall (the port), and the design of the handle. In general terms, the surgeon needs to squeeze harder, bend the wrists more, and hold their arms higher when using laparo- scopic instruments compared to open instruments. These factors, together, can produce substantial hand and shoulder fatigue and dis- comfort during laparoscopic surgery [2].
No single laparoscopic instrument design is substantially superior to others, so each surgeon needs to choose the design(s) that best achieves the following goals:
Visual angle to monitor 15–40 degrees below
line of sight
Instrument handles at elbow height
Foot pedal at same level and near foot
Figure 48.2. Key elements of the ergonomic laparoscopic surgeon.
a. Enables the surgeon to keep both wrists in a neutral (unbent) position b. Permits the surgeon to keep both arms at the sides of their body c. Avoids pressure points on the hands
d. Allows the surgeon to apply force with a power grip (hammer or gun- style) hand position
e. Allows fine manipulation with a precision grip (pencil or forceps- style) hand position
When it is necessary to apply continuous grasping force to tissues, seek an instrument that incorporates a locking or ratchet mechanism that will maintain the force. “Palming” an instrument (removing the thumb from the ring and placing the palm against the handle) can reduce the amount of wrist flexion and increase the surgeon’s power when grasping tissues for a long period of time or when an especially forceful grip is required. When even larger forces must be applied to tissue, such as during stapling, seek instruments that provide a power- grip handle with large smooth contact surfaces.
Most laparoscopic instruments are designed with either a pistol grip-type handle or an axial (in-line) handle. The pistol grip allows the hand to remain at an angle to the instrument shaft and can lessen the ulnar deviation needed to use the axial handles. However, the axial handles permit the use of a fine grasp and rotation of the instrument in the hand that can be useful in fine manipulation and suturing. The most important features to look for in laparoscopic instruments are these:
a. Instrument handles that are smooth and broad surfaced to avoid pres- sure points and finger entrapment
b. An internal mechanism that is smooth, precise, and allows good tactile feedback from the tip of the instrument to the handle
c. Easy and intuitive access for the fingers to any additional controls that govern shaft rotation, jaw-locking, or electrocautery or suction activa- tion
d. Sturdy insulation of the instrument shaft all the way to the base of the jaws to avoid stray electrocautery injury during use
e. An electrocautery connector pin that keeps the electrocautery cable out of the way of the surgeon’s hand during use of the instrument f. Instruments that require substantial force to use (staplers, clip appli-
ers, heavy graspers) should have a broad and smooth pistol-type hand that permits the surgeon to use a power-grasp hand position
G. Laparoscopic Surgical Technique
Performing laparoscopic surgery requires the proper placement of the access ports and the efficient and safe use of the instruments to accomplish tissue dis- section, division, sealing, and reapproximation. The location of the access ports is critical because they determine the reach and the working angle of the instru- ments passed through them. A manipulation angle range of 45°–75° (in the hor- izontal plane, the acceptable range of angles between the instruments inserted through the different ports) with equal azimuth angles (the elevation angle range in the vertical plane) is recommended [8]. Ideally, the surgeon maintains similar elevation angles for each of the instruments that they hold.
Instruments should be inserted such that at least half of the instrument is inside the patient. If the instrument is utilized while inserted less than half of its length, excessive motion at the shoulder will be required, which is likely to fatigue the surgeon [7]. There are no data to strongly support the use of one type of laparoscopic instrument handle design over another. Laparoscopic suturing is generally best performed with axial (in-line) instruments because they allow the surgeon to finely grasp the needle holder and facilitate rotation of the instrument with simple wrist motions. Laparoscopic needle drivers and forceps should incorporate a locking mechanism to hold the needle, thus obviating the need for the constant application of force by the surgeon. Several excellent reviews of suturing technique have been published [6, 13]. In addition to the choice of instruments and port locations, the ergonomic principles stated in the previous sections should always be followed.
H. Team Performance in Laparoscopic Surgery
A well-trained team always outperforms a less cohesive group. This dictum is also true in surgery, and particularly during laparoscopic surgery where more complex technology is being used [10]. The anesthesiologist must be aware of the potential complications of both pneumoperitoneum and the specific laparo- scopic procedure to be performed and must communicate well with the surgical team throughout the procedure, especially during critical parts of the operation.
Likewise, when problems arise, frequent and thorough communication between the surgeons and anesthetists must be maintained. The operating room nurses must be trained in the setup and use of the equipment and instruments. Often a medical technician or biomedical engineer is employed to set up and maintain the equipment. It is invaluable to have a trained and knowledgeable team to trou- bleshoot the not-infrequent equipment and instrument problems that arise during laparoscopic operations.
Ideally, each hospital or ambulatory center should create a dedicated laparo- scopic surgery team. The members of this team would train together and develop a common understanding of the instrumentation and equipment needed for each procedure. The other nurses of the OR staff, who usually do nonlaparoscopic cases, should all undergo a basic equipment, instrument, and procedure orien- tation so that they will be able to staff laparoscopic procedures at night or when emergency cases arise.
I. Errors and Complications in Laparoscopic Surgery
1. Since the publication of the Institute of Medicine report To Err Is Human in 1999 [5], the prevention of human error in medicine has become a priority in the U.S. health care system. Human error and adverse patient events (complications) in laparoscopic surgery can be minimized by proper training and supervision along with attention to
key ergonomic and human factors issues in the operating room. Never- theless, experience has shown that even experts are subject to human error. Thus, it is important that we create a system of patient care that minimizes the possibility of errors, promptly detects errors when they occur, responds appropriately to errors to minimize the adverse effect, and allows us to learn from our mistakes. Errors and complications should be seen as an opportunity to learn and to make positive changes, and not used to blame or criticize those involved.
Errors can be categorized as follows:
a. Mistakes: The surgeon makes a mistake because of an incor- rect interpretation of the anatomy or situation [e.g., mistak- ing the common bile duct (CBD) for the cystic duct and dividing it]. Similarly, the overzealous application of a “rule”
that may be inappropriate in certain situations may lead to an error (e.g., CBD filling defects found on cystic duct cholan- giogram should result in CBD exploration).
b. Slips: The surgeon makes the right decision but carries out the wrong action (e.g., presses the “cut” pedal instead of the
“coagulation” pedal on the electrocautery).
c. Lapses: The Surgeon forgets to perform a procedure or a spe- cific step in a procedure (e.g., forgets to check the integrity of a colonic anastomosis using air insufflation before closing).
2. Slips are much more easy to detect and correct (“oops, I stepped on the wrong pedal!”) than mistakes. Slips can best be prevented by better design and layout of the workplace, instruments, and controls follow- ing the guidelines in this chapter. Mistakes are harder to detect and are best prevented through better feedback (visual, auditory, manual) to the surgeon and improved training.
We can avoid common slips and mistakes in laparoscopic surgery by:
a. Ensuring that all OR personnel obtain adequate training and proctoring for all procedures
b. Striving to be in good physical and mental condition before surgery
c. Positioning all the equipment and instruments in a comfort- able, efficient, and ergonomic manner
d. Maintaining a clear view of the operative field and instru- ments at all times
e. Converting to open surgery if the exposure is poor or the potential for complications seems higher than usual When slips or mistakes occur, the surgeon should view them as a learn- ing experience and try to make changes in the above areas to lessen the likelihood that they will occur again.
J. Operating Room Setup
1. The overall OR layout is important because it affects setup and turn- around times and the efficiency of surgery, as well as patient and staff safety. The modern OR is a temperature-controlled and, it is hoped, aseptic environment that must accommodate the presence and move- ment of multiple people as well as numerous small and large equip- ment items.
2. The OR for laparoscopic cases should be larger (at least 400 square feet in area) than a typical room used for open surgery to accommo- date the additional equipment. The traditional laparoscopic setup makes use of large multilevel wheeled carts to house the equipment.
This system has several disadvantages. It requires multiple power cables from the wall to the cart as well as numerous cables and tubes coursing from the cart to the surgical field and from cart to cart. Equip- ment carts are large and heavy and cannot be ergonomically positioned in the OR; carts also do not permit each piece of equipment to be indi- vidually placed in its optimal position. Finally, carts are cumbersome to move in, out, and about the OR. A better solution is to place the large equipment items on movable ceiling-mounted booms or wall-mounted storage areas and to route all cables and tubes through single conduits that are off the floor (e.g., ceiling-mounted booms) to the surgical field.
3. Unfortunately, because of cost issues, it is not always possible to work in a room with ceiling-mounted booms; when working in a room where the equipment is on carts it is important to develop a strategy to deal with the myriad of associated cables, wires, and tubes cours- ing through the OR. The latter, unless carefully arranged and secured, are hazards and obstacles that impede the movement of both surgeons and OR staff and can result in the inadvertent disconnection of equip- ment, falls, or electrical injury. When setting up for a laparoscopic operation, pay particular attention to the location of large pieces of equipment that may be needed later during the case such as a fluo- roscopy unit or ultrasound machine. Position these before surgery such that they can easily be moved toward the surgical field to a place where the device can be readily utilized and their displays easily seen by the surgeons. A well-thought-out plan is needed for the routing of cables and tubes from the equipment and devices to the surgical field and to the control pedals so that the cables are as out of the way as possible and the foot pedals comfortably placed. Where feasible, cables and tubes that run to the operative field should be grouped and run off the field together (either off the head or the foot of the table) such that movement of the surgeons is not impeded. Floor-based tubes and cables can be taped to the floor to decrease the chances that someone will trip and fall. Ideally, the numerous cables, wires, and tubes should not pose a contamination hazard and their position should not inter- fere with the operation.
4. The surgical lights can interfere with laparoscopic equipment, fluo- roscopy units, or ceiling-mounted booms holding equipment or visual
displays. The lights should be positioned in the desired location (often in the midline of the patient and to each side of the surgeon’s head) before prepping the patient.
K. Summary
1. Adjust the operating table height so that the instrument handles, once inserted into the abdomen, are at your elbow height.
2. Place the visual display (monitor) directly in front of you and 15°–40°
below the line of sight.
3. Choose laparoscopic instruments that minimize wrist flexion and rota- tion and ulnar deviation.
4. Choose instruments with comfortable and efficient handles that are matched to the task you are performing (e.g., power grip for grasping chores or fine grip for suturing).
5. If foot pedals must be used, place them close to your foot and use a foot rest.
6. Where possible, use large ORs with integrated and moveable storage systems that decrease clutter and turnaround times.
7. When using floor-based equipment carts, carefully position all equip- ment so that movement in the room is not impeded and so that devices required for only one portion of the case can be easily moved to the field when needed.
8. Similarly, the cables and tubes associated with laparoscopic cases must be intelligently grouped and secured, both in the operative field and on the floor, so as to minimize the hazard they represent and to permit the flow of OR personnel and the surgeons.
9. Emphasize team training for the laparoscopic OR crew.
10. Learn to minimize the risk of slips and mistakes and learn from them when they occur.
L. Conclusion
Ergonomics describes the interaction between the user and their work envi- ronment. Laparoscopic surgery requires more physical and mental effort on the part of the surgeon and therefore mandates that very close attention be paid to the proper arrangement of the OR workspace, the choice and proper use of sur- gical instruments, the training of the OR staff, and ensuring that all staff com- municate well with each other.
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