Biomedical subjects

C Giebmeyer

Publications and source records attributed to C Giebmeyer.

4 recordsLinked to original sources

PubMed2005

Monitor position in laparoscopic surgery.

BACKGROUND: One of the key problems in laparoscopy is the ergonomic positioning of the monitor. In this study we tested task performance and muscle strain of subjects in relation to monitor position during laparoscopic surgery. METHODS: Eighteen subjects simulated laparoscopic suturing by threading tiny pearls with a curved needle. This was repeated in three monitor positions (15 min each): frontal at eye level (A), frontal in height of the operating field (B), and 45 degrees to the right side at eye level (C). Subjects were not allowed to turn their heads during these sessions. After the test they were asked for their preferred monitor position. During all tests the electromyographic (EMG) activity of the main neck muscles was recorded and the number of pearls was counted. RESULTS: The EMG activity was significantly lower for position A compared to positions C and B (p < 0.05). No significant difference was found between positions B and C. The number of threaded pearls as an indicator for task performance was highest for position B. The difference was statistically significant compared to position C (p = 0.0008) but not between positions A and C (p = 0.0508) or A and B (p = 0.0575). When asked for the preferred monitor position, nine subjects chose two monitors in the frontal positions A and B. No subject preferred the monitor at the side position (C). CONCLUSION: Regarding EMG data, the monitor positioned frontal at eye level is preferable. Reflecting personal preferences of subjects and task performance, it should be of advantage to place two monitors in front of the surgeon: one in position A for lowest neck strain and the other in position B for difficult tasks with optimal task performance. The monitor position at the side is not advisable.

Computer Terminals↗

PubMed2004

Ergonomic aspects of five different types of laparoscopic instrument handles under dynamic conditions with respect to specific laparoscopic tasks: an electromyographic-based study.

BACKGROUND: The ergonomic deficiencies of various minimally invasive surgery (MIS) instrument handles are well-known. In the past, many studies have been performed to gain a better understanding of ergonomics in MIS. The current study investigates muscle strain during various dynamic tasks with different instrument handles. METHODS: Five different handle designs were tested: the axial handle (Aesculap), the vario handle (own model), multifunctional and ring handles (both Karl Storz), and the shank handle (Wilo). Ten subjects without any surgical training tested the following instrument functions: precise dynamic movement, rotation of the closed instrument, and simultaneous opening and closing of the effector. During these three trials, task performance (errors/duration) and the electromyographic activity of the hand and lower arm muscles were measured. RESULTS: Regarding the errors and the time required to carry out the tasks, the five handles showed similar results. The muscle activity was lowest for the precise dynamic movement task and highest during the rotation task. The axial handle required significantly more muscle activity than all other handles. CONCLUSION: On the basis of these data, it was possible to construct characteristic muscle activation patterns for each handle. However, these patterns were not task specific. Accordingly, they may form a basis to improve the ergonomics of MIS handles with regard to muscle strain.

Electromyography↗

PubMed2002

Ergonomic aspects of four different types of laparoscopic instrument handles with respect to elbow angle. An electromyogram-based study.

BACKGROUND: Only few studies have tested different ergonomic aspects of the working posture assumed by laparoscopic surgeons. Although no experimental data are available for a laparoscopic setting, a working posture with a horizontal forearm or an elbow angle 90 degrees to 120 degrees has been recommended for performing minimally invasive surgery (MIS). The comparison of electromyogram (EMG) activities in different muscles provides information about the force developed by each muscle and allows assessment of its contribution to a functional movement. The current study aimed to investigate whether certain handles do not support this posture. METHODS: For this study, 12 volunteers were postured in two different standardized arm positions, defined by elbow angles of 90 degrees and 120 degrees. They were manipulating a 0.1-N and a 2.5-N microswitch with four different types of instrument handle design: axial handle, ring handle, shank handle, Hirschberg handle. During the test, the EMG activities of five forearm muscles were recorded and normalized with respect to the maximum voluntary activity of the respective muscle. RESULTS: Virtually no significant difference in EMG activity was found between the two elbow angles in any of five forearm muscles for a simple grasping maneuver. Thus, the muscle activity required to manipulate different types of MIS handles is similar for the elbow angles of 120 degrees and 90 degrees. CONCLUSIONS: The current study did not show relevant differences between the two elbow angles for any of the four handles during a simple grasping maneuver with respect to the force required in the main forearm muscles.

Elbow↗

PubMedDate not supplied

Ergonomics: requirements for adjusting the height of laparoscopic operating tables.

BACKGROUND AND OBJECTIVES: In the last few years many new instruments and devices have been developed and introduced into the operating room (OR). A debate has been ongoing about the optimal ergonomic posture for the operating staff. From practical experience, we have learned that the operating tables cannot be adjusted adequately to allow surgeons of different stature to maintain a comfortable posture. The goal of this study was to establish the most ergonomic table height for the particular physique of the surgeon and the different types of laparoscopic instrument handles that he or she uses. METHODS: In a simulated model, two probands of different stature (50th [BS 50] and 95th [BS 95] percentile) used laparoscopic instruments with four different handle designs (shank, pistol, axial, and rod). The instruments were inserted into a board in three different angles ([IA] = 20 degrees, 30 degrees, 40 degrees). Additionally the elbow angles (EA) of the volunteers were fixed to either 90 degrees or 120 degrees. For every variable (size of surgeon and his or her elbow angle, design of handle, insertion angle of the instrument) the height of the board, as a parameter for the level of the abdominal wall of a patient with pneumoperitioneum, was measured from the floor. RESULTS: All parameters had an effect on the optimal operating table height. The lowest required operating table level was 30 cm, the highest was 60.5 cm. In laparoscopic surgery-long shafted instruments and patients with pneumoperitoneum-the tabletops are too high for over 95% of all surgeons. As skin incision and wound suture are performed the conventional way, the operating tabletop must be adjustable up to the common height of 122 cm. The maximal difference between the optimal heights of the OR-table for one volunteer using two different handles with different insertion angles of the instruments (BS 95, EA 90 degrees, IA 20 degrees, rod handle to BS 50, EA 120 degrees, IA 40 degrees, axial handle) was about 27 cm. CONCLUSION: New operating tables with a much lower adjustability are necessary to fulfill ergonomic requirements. The use of differently designed handles can hinder the ergonomic posture of the surgeon, because each handle requires a different working height.

Equipment Design↗