This paper addresses the problem of adjusting the operating (OR) table to the optimal ergonomic height.

Almost a hundred years ago, the adjustability of the operating table for open surgery had already been discussed. De Quervain pointed out the importance of adjustability of the table for the positioning of the patient in relation to the surgeon.^12,13

The adjustability of current operating tables ranging between 73 cm and 122 cm¹⁴ is sufficient for open surgery. Only rarely does a surgeon wish to position the table above or below this height in traditional surgery.

In laparoscopic surgery, though, the situation is radically different. Often the table cannot be lowered sufficiently for precise and relaxed work. Surgeons compensate for this by elevating their arms, which can be very fatiguing,¹⁵ or by climbing on a step. The small area available for surgeons' feet on a step limit their movements as well as their access to foot switches needed for high frequency (HF) surgery and eventually also for the suction and irrigation device. These devices also have to be placed on this step, and quite often these foot switches fall off⁴ (Figure 1).

Four laparoscopic instruments with different handle types were fixed to the trocar. The distance between the perspex board and the transition of the instrument's handle and its shaft was kept at 25 cm. By doing so, an insertion of one third of the shaft into the abdomen was simulated, a situation that is common during surgery.

The following instruments and handles (Figure 2) were tested:

To evaluate the optimal operating table height in relation to the surgeon's height, the following experiment was performed by a tall (188 cm-95th percentile) and a smaller proband (172 cm-50th percentile).¹⁹ Therefore, the stature of approximately 50% of surgeons worldwide is represented.

The probands were standing upright next to the tripod. They were required to assume an “ergonomic basic body posture” as described in previous publications.^4,5 With this posture, the elbow angle is between 90° to 120°. In this position, it is possible to work for a long period of time without getting fatigued. The elbow of the right arm was fixed with two plaster splints at angles of 90° and 120°. The alignment of the instrument, the trocar, and the perspex board was adjusted in height to the tripod in a way that the right hand could grasp the handle as comfortably as possible (Figure 3).

The various handle types for laparoscopic instruments require different table heights for ergonomic manipulation when used at the same insertion angle. The axial handle always requires the lowest adjustment of the OR-table, followed by the rod or shank handle. This difference varies between 4.5 cm (IA=20°, EA=90°, small volunteer) and 14 cm (IA=40°, EA=90°, tall volunteer).

The lowest working height was required for the axial handle, which is held from above. For the small test person who had to work with the elbow angled at 120°, the abdominal wall of the patient had to be 70 cm high, corresponding to the height of the proband's upper thigh. The tall proband needed an elbow angle of 90° when working with a shank handle and a board height of 103.5 cm, which is about 10 cm below the umbilicus (114 cm) of the proband. Therefore, the maximal vertical range of the laparoscopic operating table is 33.5 cm. For a patient with a sagittal abdominal diameter of 40 cm (for a pneumoperitoneum), the lowest operating table level should be about 30 cm, which corresponds to the middle of the lower leg of the smaller proband.

The highest working height (103.5 cm) was required for the tall proband manipulating the rod handle at an insertion angle of 20° and with an elbow angle of 90°. This height of the abdominal wall is approximately 10 cm below the possible range of currently available operating tables (73 cm table height + 40 cm patient diameter). Therefore, these tables are too high to allow for adequate working conditions for at least 95% of surgeons performing laparoscopic procedures.

The manipulation of an axial handle is awkward in this position, causing severe pain, cramps, and fatigue.¹⁵ For the rod handle, the horizontal arm position recommended by Berguer¹¹ may be adequate, as it usually results in an almost neutral wrist angle.

To determine adequate operating table heights, other elbow angles should also be considered. Bullinger recommends an elbow angle of 90°-120° for continuous work.²⁰ Contrary to the 90° angle, the 120° angle requires an operating table height that–according to the type of handle used and the height of the surgeon–should be as much as 10 cm lower. A table that can be adjusted within this range by the surgeon him- or herself seems desirable. This could be accomplished either by a foot switch¹⁴ or a voice or hand controlled switch.

Differently designed handles should not be used simultaneously at the same insertion angle, because this requires different postures at shoulder level for adequate manipulation. But sometimes, when working with instruments at different insertion angles, it may be necessary to use different types of handles to achieve an ergonomic posture.

The difference between the two extreme positions, small surgeon, axial handle, EA 120°, IA 40° vs. tall surgeon, rod handle, EA 90°, IA 20°, is 33.5 cm. The lowest level for the abdominal wall is 70 cm. Accordingly the table should be positioned at a height of 30 cm for a patient with a sagittal abdominal diameter of 40 cm. Although, below the knee of the surgeon, even this level may be too high for some surgeons because the proband's height was at the 50th percentile. OR-tables that fit to 50% of surgeons could be a big advantage, because it is alarming that the currently available operating tables are too high for 95% of surgeons performing laparoscopic procedures.

For the lower position of the operating table, the following hygienic aspects should be considered: the distance between the operating level (abdominal wall) and the “floor” is equally reduced by the common use of a standing stool for different heights of surgeons and assistants. These stools, however, are neither convenient nor large enough to accommodate the surgeon and the paddle equipment. Furthermore, they also cause problems with regard to hygiene as it does not make a difference whether a standing stool elevates the floor or the table itself is lowered. For an ergonomic working posture, it is necessary to position the patient's abdominal wall at the height of the upper thigh as described by Berguer¹¹ and demonstrated in the present study. This interferes with the classic teaching that the surgeon's gown is only sterile above the belt; however, a literature search did not reveal any data that would support this rule. To avoid contamination via the surgeon, the gown should reach down to the ankles.

In open surgery, the patient is also often positioned very low. For example, in the reversed Trendelenburg position, the foot part of the operating table, depending on the model, may come close or even touch the floor.

Following consultation with the Institute for Hospital Hygiene and Environmental Medicine, University Hospital Freiburg, we assume that such a low positioning of the patient per se does not bear the danger of bacterial contamination provided the floor is regularly cleaned in between surgical procedures. However, as in open surgery, the drapes should not touch the floor.

Therefore, the draping system has to be modified to meet the hygienic requirements for a low table height in laparoscopy as well as to allow for extreme positions in open surgery.

In the future, the problem of inadequate adjustability of OR-tables may be solved in part by the advent of robotically assisted surgery. For now, however, robotics has technical, hygienic, and ergonomic deficiencies that should be solved over the next decades. Furthermore, surgical procedures requiring the manual expertise of a surgeon and, therefore, an ergonomic work environment has to exist.