Surgical technology has substantially advanced and is constantly growing beyond laparoscopic and robotic surgeries [1]. Although advances in minimally invasive surgery (MIS) have considerably expanded the indications for improved surgical outcomes, surgeons have been exposed to numerous occupational hazards [2-4]. The physical burden of MIS is thought to be due to the inevitable posture of the operator during surgery, which is caused by several factors that include limited visibility of the surgical field, decreased degrees of freedom, the fulcrum effect, and inadequate instrument design [5-7]. This physical burden shows differences in the workload for each body part, depending on the surgical method (Fig. 1) [1,8].

Fig 1. Differences in workload depending on body part according to the surgical method.

Work-related injuries and burnout can occur because of excessive physical and cognitive demands, insufficient work-life balance, and pain or fatigue [9]. Work-related musculoskeletal disorders (WMSDs) affect 87% of surgeons, and burnout affects 40% of surgeons [2,10]. Although most surgeons recognize work-related musculoskeletal symptoms, < 30% seek medical treatment for these conditions, because of the historically self-sacrificing culture in surgery [8].

The etymology of “ergonomics” derives from the Greek words ergon (work) and nomos (laws). In 2000, the International Ergonomics & Human Factors Association (IEA) defined ergonomics in 2000 as the scientific field that studies how people interact with other components of a system and the profession that uses theory, principles, data, and methods to design systems that optimize human well-being and the entire system’s performance [11,12]. The IEA has adopted the practice of referring to ergonomics and human factors as a single phrase (human factors/ergonomics, or HFE), or as an interchangeable pair [12]. Domains of HFE include physical, cognitive, and organizational ergonomics [12].

Since its inception in the early 1900s, the field of ergonomics has made significant advances in large corporations, the military, and athletics to maximize performance and reduce injuries. Recently, it has been expanded to include healthcare settings [7].

The Centers for Disease Control and Prevention defines WMSDs as “musculoskeletal disorders (comprising injuries or disorders that affect the joints, cartilage, muscles, nerves, tendons, and spinal discs) to which the work environment and work performance significantly contribute; and/or to which work conditions exacerbate or prolong the condition” [13]. Kroemer classified such injuries into three stages: symptoms in stage 1 subside during working hours; stage 2 symptoms do not resolve overnight after the workday; while stage 3 symptoms persist even at rest; they disrupt sleep, and persist for months or years [14-16].

From 2016 to 2020, WMSDs comprised approximately 56% to 65% of all occupational diseases in Korea, whereas traditional occupational diseases, such as pneumoconiosis, hearing loss, and organic solvent poisoning, comprised only 25% to 35% [17]. The steady decline in the incidence of traditional occupational diseases owing to industrialization and the fortification of safety and health management systems through the enactment of pertinent laws and regulations may account for the comparatively high incidence of WMSDs [17].

Although WMSDs are a leading cause of injury in healthcare professionals, interventions to reduce and prevent WMSDs in healthcare professionals remain fragmented [18]. A systematic review demonstrated that interventions significantly decreased the risk of WMSDs in healthcare workers [19]. In consequence, the government and industry must implement preventative measures to decrease WMSDs [17,18].

Since the inception of surgery, open surgery has been a widely used approach [20]. In the hepato-biliary-pancreas (HBP) surgical field, open surgery is the standard procedure, considering the complex anatomy, difficult procedures, and time-consuming operation. Laparoscopic surgery has markedly changed the traditional open surgical approach, because of the many benefits it offers to patients through an MIS [20,21]. Laparoscopic surgery is associated with decreased postoperative discomfort and accelerated recovery, leading to short hospitalization periods [22,23]. Additionally, it provides notable advantages, such as improved wound cosmesis and reduced wound complication rates [22].

However, laparoscopic techniques utilizing long instruments with two-dimensional (2D) displays pose various ergonomic risks to the surgeon [20,24,25]. It has been reported that 87% of surgeons who regularly perform MIS experience physical discomfort [2,22]. WMSDs are more prevalent after laparoscopic surgery than after open or robotic surgeries [22]. Laparoscopic surgery induces more intense pain in the neck, shoulders, and upper/lower extremities, as well as more pronounced symptoms of fatigue and numbness than open surgery [8].

Body positioning guidelines, which are generally applicable to both open and laparoscopic surgeries, recommend maintaining the body in a position as close to neutral as feasible [7,20]. A systematic review reported that excessive neck flexion > 30° was associated with cervical spine dysfunction [26]. When examining the surgical field, the ideal neck flexion angle should not exceed 30° [20,27]. Surgeons should relax the shoulder and upper arm, and avoid excessive or prolonged shoulder abduction and internal rotation, which place the greatest tension on the deltoid and trapezius muscles, and cause WMSDs [7]. Shoulder abduction should be maintained below 30°, the upper arm should be positioned perpendicular to the floor, and during surgery, the surgeon should briefly stretch and rest to relieve muscle fatigue [20]. Prolonged static loading and frequent and vigorous muscle contractions in the neck and shoulders contribute to the development of WMSDs, including tension neck syndrome, rotator cuff tendinitis, and impingement syndrome in the shoulder [28]. The forearm should be parallel to the floor, and the elbow angle should be maintained at 90°−120° [6,29-31]. The wrist must also be in a neutral position, and care must be taken to ensure that inevitable extreme excursions do not consume 30% or more of the operation time [20]. In addition, surgeons must avoid prolonged static positioning by intermittently moving the wrist and hand to prevent lactic acid accumulation and fatigue [30]. Moreover, it is advisable to prevent pelvic girdle asymmetry, and evenly distribute the body weight [7,32]. Using an anti-fatigue floor mat can help alleviate the pain associated with standing for long periods [33].

The height of the operating table is a major factor that worsens WMSDs because of equipment constraints, and the need for compromise among the surgical team [9]. If the table is too high, the surgeon will have to compensate by raising their arm and changing the angles of their forearm and wrist to grip the instruments, which can cause joint hyperextension, fatigue, and pain [7]. The optimal operating room table height for open surgery is 5 cm above the elbows for precision tasks, and 5−10 cm below the elbows for other tasks [22]. In contrast, the operating room table height in laparoscopic surgery is recommended to be 70%−80% of the elbow height to maintain an elbow angle of 90°−120° [5,9,20,22]. In addition, in both open and laparoscopic surgeries, the table height is commonly set based on the tallest person on the surgical team, while the remaining team members compensate for their lesser height using step stools [20].

A surgical loupe can reduce neck and upper back strain by optimizing the working distance and minimizing the neck angle to < 25°, with an increased declination angle [34]. When choosing surgical loupes, it is recommended to balance the weight and durability, and select a frame that is as light as possible [35]. The foot pedal should be positioned near the foot and aligned with the target instrument in the target quadrant, without needing to balance on the other foot [20,29,36]. The dorsiflexion angle of the foot, which positively correlates with the average dynamic plantar pressure, should not exceed 25° when manipulating the foot pedal [6,37,38].

In addition, proper positioning of the surgical monitor is essential to ensure optimal ergonomics, particularly during laparoscopic surgery [20]. There must be at least two 24-inch or larger monitors in the operating room, and team members on both sides of the patient must be able to see the screens [7,20]. The surgeon’s monitor ought to be positioned immediately in front of them [20]. The ideal distance between the surgeon and monitor is 140−305 cm; however, this may vary depending on the surgeon’s visual acuity, screen size, and resolution [20]. Improper height settings of the monitor can lead to increased activity of the neck extensor muscles [39]. When the head and neck are neutral, the ear-eye line is inclined 15° from the horizontal [40]. Therefore, to maintain an ergonomic neck position, the top of the monitor should be positioned at eye level, so that the angle between the surgeon’s eye level and the center of the monitor does not exceed 30° [20].

Ergonomic challenges are associated with open and laparoscopic instruments [5]. The instruments used in open surgery have multiple degrees of freedom, allowing for dynamic movement. However, laparoscopic instruments have only four degrees of freedom (up-down, left-right, in-out, and rotational); therefore, their movement is limited [7]. Furthermore, the grasping force during laparoscopic surgery is six times greater than that required for open surgery, exacerbating hand discomfort and pain [7]. Additionally, laparoscopic surgery is limited to a 2D view of the surgical site, and tactile feedback is lost [7]. Therefore, the complexity of surgery increases and requires high concentration, ultimately leading to a static posture [5,7]. A paradoxical fulcrum effect with tremor enhancement occurs when the internal side of the laparoscopic instrument that passes through the trocar fixed to the abdominal cavity wall moves in the direction opposite to the surgeon’s hand movement, and the working angle becomes unnatural [5,7,41]. To address these difficulties, it is highly advisable to aim for a 60° working angle between the instruments in both open and laparoscopic surgeries, while maintaining a natural position for the upper limb [7,20,29]. In particular, efforts are needed to consciously reduce grip strength to decrease hand fatigue in laparoscopic surgery, and continued improvement in instrument design that takes this into account will be necessary [29,42].

Fig. 2, 3 summarize the ergonomic recommendations for open and laparoscopic surgeries, respectively.

Fig 2. Ergonomic recommendations for open surgery.

Fig 3. Ergonomic recommendations for laparoscopic surgery.

Robotic surgery, which has been developed relatively recently, has advantages over other surgical methods in that it reduces bleeding, shortens hospital stay, and decreases complications, even in advanced HBP surgery [43,44]. Compared with laparoscopic surgery with 2D visualization, robotic surgery with 3D visualization offers the advantages of tremor filtering and motion scaling during instrument manipulation, resulting in enhanced surgeon dexterity [44]. Robotic surgery uses seven degrees of freedom to enable precise surgery by converting awkward postures, such as counterintuitive arc-shaped movements, into natural and precise hand and wrist movements [5,7]. Additionally, when operating while seated, unequal weight bearing on the lower extremities can be prevented [45]. Although robotic surgery is generally known to be more ergonomic than laparoscopic surgery, unresolved ergonomic challenges in robotic surgery remain [20,46-48].

In robotic surgery, surgeons mainly interact with the console that they directly look at and operate while sitting [20,22]. Therefore, proper placement of the surgeon and the console is imperative for ergonomics [20,22]. Optimal body alignment is crucial in robotic surgery [20]. Failure to maintain a neutral posture can cause strain in the neck and shoulder [49,50]. To avoid this issue, back flexion should be limited to < 15°, and neck flexion should not surpass 25° when seated on a chair during robotic surgery [20,49]. Thus, it is advisable to use a chair with sufficient lumbar support and adjustable height [20,51]. The chair height should be adjusted so that the operator’s thighs are parallel to the floor, and the knees are bent 90° [20,52]. Furthermore, the height of the set armrest must be adjusted to achieve relaxed shoulder and forearm positions, with the elbow angle ranging 90° to 120° [20,53]. The chair should be positioned close to the foot pedals for convenient access, and should have lockable wheels [20,53]. The feet should be placed with the knees in a neutral posture at an angle of approximately 90° [52]. When using foot pedals, dorsiflexion should be limited to < 25°, similar to that in open/laparoscopic surgery [20].

Fig. 4 summarizes the ergonomic recommendations for robotic surgery.

Fig 4. Ergonomic recommendations for robotic surgery.

Advances in sophisticated surgical techniques have provided various benefits to patients. However, increased technical complexity places a considerable physical burden on surgeons. By recognizing the ergonomic hazards inherent in the operating room and actively striving to mitigate them, surgeons can alleviate physical strain and enhance their overall well-being. To achieve this, research on scientific evaluation and the improvement of ergonomic risks must continue.

This study was supported by the Research Program of the Korean Association for the Hepato-Biliary-Pancreatic Surgery for 2022 (KAHBPS-22-08).

None.

No potential conflict of interest relevant to this article was reported.

Conceptualization: All authors. Data curation: YJC. Methodology: All authors. Visualization: YJC. Writing - original draft: YJC. Writing - review & editing: All authors.