393back twisted and laterally flexed (Fig. 22.2) [ 66 ]. The asymmetric loading of the
spine that occurs in these postures leads to an increased risk of vertebral disc hernia-
tion [ 67 , 68 ]. Further, the traditional belief that open surgery is more ergonomic
than laparoscopic is now being challenged as electromyography studies of the upper
extremities show increased activity during open cases as compared to laparoscopic
cases [ 65 ].
Laparoscopic Surgery
Laparoscopic surgeons often assume an upright, straight-back stance with fewer
trunk movements and less weight shifting than surgeons performing open surgery
[ 63 , 69 ]. Long periods in such static postures lead to prolonged isometric muscle
contraction which decreases muscle perfusion and can increase muscle fatigue and
pain [ 70 – 72 ]. Given the use of monitors for visualization, minimally invasive sur-
geons, including endoscopists, have increased eye strain and mental stress due to
loss of depth perception with a two-dimensional image [ 73 , 74 ]. Increased mental
stress has been directly related to worsening neck strain [ 75 ]. Additionally, poor
monitor placement can greatly influence neck posture and lead to neck and shoulder
strain [ 76 , 77 ]. Repetitive motions such as looking back and forth from the monitor
to the surgical site increase the risk of overuse injuries [ 78 ]. Laparoscopic instru-
ments pose significant challenges as they decrease tactile feedback, magnify natural
hand tremor, and require four to six times more force to complete the same task as
in open surgery [ 5 , 66 , 79 ]. The physical demands of MIS, specialized equipment,
and mental intensity in the operating room are only a few factors that may contrib-
ute to muscular strain and injury [ 80 ].
Fig. 22.2 An example of
a common but incorrect
body posture with the back
twisted and laterally flexed
22 Surgical Ergonomics