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PubMed2004

Ergonomic assessment of the static stress confronted by surgeons during laparoscopic cholecystectomy.

BACKGROUND: Only a few reports on static strain in the spine, neck, and head of the surgeon are available, describing it as "distinctly harmful." The aim of this study was to objectively prove the static burden during laparoscopic operations. For this, new industrial software called PCMAN was used, capable of measuring and comparing the postures of the surgeon at different monitor placements. METHODS: Two simultaneous and synchronized video recordings of laparoscopic cholecystectomies (LC) were done using miniDV digital camcorders with the cameras standing at a 90 degrees angle to each other. Twenty operations were performed using two different placements of the monitor. In 10 cases, the monitor was placed at the patient's head in the center, and in 10 cases at the left side of the patient. Using the time codes of the recordings, different steps of the operation were identified, and the duration of these measured in seconds. Very characteristic, longer lasting postures were imported to and analyzed with the software. Results of the different setups were compared to each other, and to an "ideal" comfort posture. RESULTS: During the intermediate steps of the operations the rate of static phases is significantly higher. Measuring the typical postures of these phases the trunk and head are significantly more rotated and bent than in comfort positions. When the monitor was at the side of the patient facing the surgeon, results were closer to the comfort posture. CONCLUSIONS: It was proven that surgeons are confronted by significant static burden during LC. The software used was able to evaluate objectively the static posture of the surgeon during series of LC. Results also confirmed that the position of monitors significantly influences the surgeon's posture. Best setups for the whole team can be achieved by adjustable multiple monitor systems.

Adult↗

PubMed1994

Synthesis of ethological studies on behavioural adaptation of the astronaut to space flight conditions.

The motor behaviour of the astronaut as revealed in his movement, posture and orientation is treated as observable evidence of the subject's adaptation to space flight conditions. In addition to the conservative physiological homeostasis, the quantitative description of the astronaut's motor activity in microgravity is postulated in terms of an innovative regulation, within a temporal dynamic. The proposed ethological method consists of first drawing up a specific behavioural repertoire and then of using video recordings of space missions to describe each of the behavioural units observed in the ongoing flux context in which it occurred. Finally the data is quantified into frequencies of occurrence, transition and association and completed with factorial correlation analysis. Comparison of ground training (g = 1) and space flight (g = 0) between the first and last day of a mission up to return to Earth gravity simulated by an anti-orthostatic decubitus experiment, reveals the nature of the adaptive strategies implemented. These strategies are evidence of changes in the behavioural repertoire including the search for predominantly visual environmental cues and the progression of motor skill during the flight. The pre-flight period is defined as a phase involving automizing of motor patterns and the post-flight period as rehabituation of strategies which have already been acquired. The phenomena observed are discussed in terms of the new spatial representation and the body image, constructed by the astronaut during his adaptation. They are considered to be optimizing for the subject's relation to his environment.

Adaptation, Physiological↗

PubMed2002

Effect of trotting speed, load and incline on hindlimb stance-phase kinematics.

The objective was to understand how the stance-phase kinematics of the hindlimb of trotting horses change with speed under 3 conditions (level, loaded and incline), to compare our results with the predictions of the spring-mass model and to help focus our future studies of muscle function. Video recordings were made of 5 Arabian horses trotting on a treadmill. Five consecutive strides were digitised and averaged for each trial. The angle-time diagrams were qualitatively similar to those reported previously. As speed increases, the range of motion of the hindlimb increases, as predicted by the spring-mass model. This is the result of increased range of motion in the coxofemoral and tarsal joints. The hindlimb does not 'land short-take off long'. When trotting up an incline, the hindlimb undergoes a greater range of motion because of increased retraction resulting from increased extension of the coxofemoral joint. At hoof contact on an incline, the 3 proximal joints are more flexed than on the level. Carrying a load had no effect on kinematics. These results suggest that there may be larger changes in strain with speed in muscles acting at the coxofemoral and tarsal joints than at the femorotibial joint, and that locomotion up an incline will change muscle strain more than carrying a load.

Animals↗

PubMed2002

Effect of an arm sling on gait pattern in patients with hemiplegia.

OBJECTIVE: To investigate the effect of an arm sling on gait patterns of patients with hemiplegia. DESIGN: Crossover design of 3-dimensional gait analysis and concomitant video recordings performed during a single session. SETTING: Rehabilitation ward gait laboratory of a university hospital. PARTICIPANTS: Thirty-one patients (20 men, 11 women) with hemiplegia with an average age of 53.1+/-9.7 years and 31 age-, sex-, height-, and weight-matched able-bodied persons. INTERVENTIONS: All patients with hemiplegia and able-bodied controls walked at self-selected speed over a 10-m walkway, either with or without an arm sling. MAIN OUTCOME MEASURES: Time-distance, kinematic, and kinetic parameters of gait. RESULTS: The able-bodied group did not show any difference in gait parameters while using the sling. However, in patients with hemiplegia wearing a sling, walking speed and stance period of the paretic side increased, double support time of the paretic side decreased, excursion of the center of gravity (COG) decreased, and weight bearing of the paretic side increased. CONCLUSIONS: An arm sling improved gait, especially during gait training sessions of patients with hemiplegia who have impaired body image and excessive motion of the COG.

Ankle Joint↗

PubMed1999

Airway epithelium of transplanted lungs with and without direct bronchial artery revascularization.

OBJECTIVE: Normal systemic blood flow to the airways and lung parenchyma of transplanted lungs can only be re-established by direct bronchial artery revascularization. The purpose of the present study was to investigate whether such direct bronchial artery revascularization would preserve ciliary function, previously shown to be reduced in lungs transplanted without revascularization. METHODS: Twenty-five single lung transplanted patients were included in this study. Complete direct bronchial artery revascularization was achieved in eight patients. In 16 patients the procedure had either failed (n = 10) or was not attempted (n = 6). In one patient the result of the revascularization was unknown. Airway epithelium samples were obtained from the native and the transplanted lungs during bronchoscopic examinations. Airway erythema and excessive secretion were registered. The epithelium samples underwent histological examination and ciliary beat frequency was measured in vitro by video recording. Transbronchial biopsies from the transplanted lungs were examined for signs of rejection and bronchitis. RESULTS: No differences in ciliary beat frequency nor in the distribution of ciliated/de-ciliated columnar epithelium cells between native lungs and transplanted lungs with or without successful direct bronchial artery revascularization could be demonstrated. In 38% of the transplanted lungs without successful revascularization metaplastic or squamous epithelium was present, while lungs with successful revascularization had only normal columnar epithelium. Ongoing rejection or airway erythema did not influence ciliary beat frequency. Excessive secretion in the airways was the only finding associated with significantly increased ciliary beat frequency. CONCLUSIONS: Ciliary beat frequency of epithelium cells of transplanted lungs did not differ from that of native lungs and consequently direct bronchial artery revascularization did not have any demonstrable important influence. Excessive secretion in the airways was associated with increased ciliary beat frequency. The histological findings also showed that the abundance of ciliated cells was preserved in transplanted bronchi irrespective of bronchial artery revascularization. However, epithelium metaplasia was only seen in transplanted bronchi without revascularization.

Angiography↗

PubMed1998

The relation between visual acuity and the size of fixational eye movements in patients with diabetic and non-diabetic macular disease.

PURPOSE: To study fixational eye movements as a function of visual acuity (VA) in patients with diabetic maculopathy and in patients with non-diabetic macular disease. MATERIAL: Two groups of patients each with VA ranging between 0.05-0.77 were studied, i.e. 24 patients with diabetic maculopathy and 23 patients with non-diabetic macular lesions. Fixational eye movements were quantified from video recordings of the ocular fundus obtained with the Rodenstock scanning laser ophthalmoscope. RESULTS: Within both groups of patients we found a similar significantly negative relation between the amplitude of fast saccadic eye movements and the VA. Patients with VA > 0.20 showed a normal directional pattern with larger amplitudes of the fast saccadic movements in the horizontal than in the vertical plane, whereas for patients with VA < or = 0.20 the amplitudes of the saccadic movements in the vertical plane had enlarged to equal the saccadic amplitude in the horizontal plane. Four patients with VA < or = 0.10 had the fixation centre located more than three degrees (approximately 500 microns at the retinal plane) from the centre of the foveal avascular zone, whereas the fixation centre of the remaining 43 patients was within one degree of the centre of this zone. CONCLUSION: Patients with VA < or = 0.20 may have retinal areas of fixation located more than 500 microns from the fovea. This fact should be taken into account when planning retinal photocoagulation in macular disease.

Adolescent↗

PubMed2002

Arboreal locomotion in small new-world monkeys.

The postural and locomotor activity and its relation to substrates was observed in 3 Saguinus oedipus, and 3 Saimiri sciureus for comparison, during a period of 10 h for each individual. The animals moved freely in cages of 3.40 m x 3.40 m x 2.40 m (height) on rather diverse substrates. Observations were made according to the focal-animal-method, with combined instantaneous and continuous sampling. They were protocoled in schematic form and video-recorded. In addition, 3 further Saguinus oedipus were subjected to an X-ray cinematographic study on a modified treadmill to unveil metric parameters of the locomotor pattern preferred on slender and compliant ("arboreal") substrates, the walk. Independent from the substrates, the postures of the two species differed in details, as do the preferred substrates. Horizontal, comfortable substrates are favored most. Walking ranked top in frequency, followed by jumping and galloping (in a strict sense). All other locomotor modes described for primates played a minor role or lacked entirely, like the trot. Average distance of leaps was only 0.60 m, landings were mainly on the same level as take-offs. In Saguinus, the movements of both limbs, including the shoulder blade, followed the pattern common to small mammals in general: At the end of the stance phase, humerus and tibia are nearly parallel to the substrate, while just before touchdown ulna and femur are in this position. The walk in both species was surprisingly fast (1 m/s), reaching the speed of much larger cursorial animals, like humans.

Animals↗

PubMed1999

In vitro evaluation of brain lesioning electrodes (Leksell) using a computer-assisted video system.

Radiofrequency (RF) generated thermal brain lesions are widely used in functional neurosurgery. The size, shape and development of the lesions depends on system parameter settings and the electrode configuration. Difficulties in studying the effect of these factors in vivo stimulated us to develop an in vitro system for standardized comparison between different electrodes and physical parameters. A computer-assisted video system was set-up allowing continuous video recording of RF-generated coagulations in either a standard albumin solution or in the fresh white of a hen's egg as transparent test substrates. Ten lesions were made with each test electrode (two bipolar and three monopolar) in each of the two substrates at 70 degrees, 80 degrees and 90 degrees C (t = 60 sec). Due to the better homogeneity the lesions in the albumin solution were much more regular and reproducible. This made it possible to calculate the size (width 2.2 +/- 0.1 to 5.3 +/- 0.1 mm and length 3.0 +/- 0.1 to 8.7 +/- 0.3 mm) as well as the volume (8.5 +/- 1.4 mm3 to 133.5 +/- 26.8 mm3). It is concluded that this in vitro system offers a reproducible way to study and document the effect of different electrode configurations and RF-generator settings on the formation of a heat lesion. Even if the results are not directly applicable to the living human brain they give an estimate of the form and size of a coagulation lesion and can be of value for standardized comparisons between different electrodes.

Brain↗

PubMed2001

[Role of videofluorography in the study of esophageal motility disorders].

PURPOSE: To repropose the importance of videofluoroscopy in the study of esophageal motor disorders, comparing the radiologic and manometric results; the manometric results are considered the reference parameters. MATERIAL AND METHODS: From 1996 to 1999, 76 patients (42 males and 34 females), were studied first using manometry and then videofluoroscopy. The patients had symptoms like dysphagia, thoracic pain or both. The manometric study was performed with a perfusional system equipped with 6 tips (4 radial for the study of the esophageal sphincters and 2 placed longitudinally for the study of the esophageal peristalsis). With the patient in a supine position we analysed 5-10 deglutitions with 5 ml water bolus at 20-25 degrees C, administered using a graduated syringe. The radiologic study was performed with a remote-control digital television system, connected to a video recorder. Three 7.5 ml bolues of high density barium suspension (250% weight/volume) were injected orally in the upright position and other three were injected in the prone position following the passage from the oral cavity to the stomach. RESULTS: The comparison of the manometric and videofluoroscopic results suggests that the total sensitivity of the radiological study in the detection of esophageal motor disorders was 92%. In particular dynamic radiologic investigation diagnosed the normal esophageal functionality in 100% of the cases, nonspecific esophageal motility disorders in 89.6%, diffuse esophageal spasm in 100% of the cases, the presence of achalasia in 90%, whereas "nutcraker esophagus" only in 50%. Videofluoroscopy therefore showed high sensitivity in four groups of the five considered. It has some limitations in the diagnosis of initial achalasia, and is not sufficiently sensitive in the diagnosis of "nutcracker esophagus". CONCLUSIONS: Videofluoroscopy is a simple method which presents high sensitivity and specificity in the detection of motility disorders of the esophagus and could therefore be proposed as the first diagnostic method in patients with specific symptoms.

Adult↗

PubMed1994

Different fate of sibling cells upon inhibition of transcription in G1.

In normally cycling populations of NIH3T3 cells, both sibling cells generated by a mitotic division require similar periods of time for completion of the cell cycle, with variations (intersibling times) of < or = 3 h for > 90% of the population. In this study, we analyzed by time-lapse video recording the effect of the RNA polymerase II inhibitor alpha-amanitin on the intersibling times of cells exposed to the drug at defined postmitotic ages. Our results led to the identification of three subpopulations of NIH3T3 cells. In the first one, both sibling cells were highly sensitive to alpha-amanitin. These cells were exposed to the inhibitor at a postmitotic age of < or = 2 h. The second subpopulation was composed of cells where one sibling showed normal kinetics of cell cycle progression, while the other sibling had an increased cell cycle length (intersibling times of up to 12 h) or did not divide at all during the period of observation. These cells were 2-8 h old at the time of treatment. In the third subpopulation, representing cells at later stages in the cell cycle, no significant increase in intersibling times was observed. These data indicate that alpha-amanitin increases the intersibling times of cells exposed to the drug during G1. In addition, our results suggest that the variable-length period of G1, thought to be located in late G1, is dependent on RNA polymerase II transcription.

3T3 Cells↗

PubMed1994

Temporal structure of a bimanual goal-directed movement sequence in monkeys.

The aim of the present investigation was to assess a bimanual goal-oriented movement sequence with particular emphasis on its temporal structure. The three monkeys (Macaca fascicularis) used in this study chose the left arm as the leading and more postural arm to reach out and pull back a spring-loaded drawer containing a food morsel. The right arm followed the left and picked up the food with a precision grip. Video recordings, trajectory recordings of the two index fingers, drawer displacement and the measurements of discrete events of the left and right hand revealed a considerable trial-by-trial variability in the temporal and spatial domain. The variability of latencies progressively increased from the initiation of the bimanual sequence to the left-hand and right-hand events defining goal achievement. The main result was that, in spite of this variability in each of the two limbs, there was an invariant left-right goal-related synchronization. The timing of the goal-related event pairs covaried and showed high correlation coefficients. Covariation of the two hands resulting in an invariant synchronization was particularly striking when monkeys performed the task without vision, and timing of right and left movement components was delayed with further increase in variability. The results indicate that, in the present bimanual skill, kinaesthetic signals may be sufficient to coordinate the two limbs in a goal-oriented unitary action in accord with a memorized plan.

Acoustic Stimulation↗

PubMed2002

Virtual laryngotracheal endoscopy based on geometric surface modeling using spiral computed tomography data.

This prospective study describes the clinical utility of virtual endoscopy based on geometric surface modeling of the laryngotracheal lumen. Eighteen children with dyspnea related to either subglottic angioma (n = 5) or laryngotracheal stenosis (n = 13) were included. All patients underwent video-recorded operative endoscopy, spiral computed tomography, and 3-dimensional reconstruction of the laryngotracheal lumen. Modeling was achieved by contour detection on spiral computed tomographic images and reconstruction using a geometric shape-recognition algorithm. The generated surface was used for diagnosis and measurement using interactive and automatic tools. Findings of virtual endoscopy and operative endoscopy were compared. Virtual endoscopy confirmed narrowing of the airway in all cases. In 9 cases, high-grade stenosis prevented complete operative endoscopy, but virtual endoscopy allowed accurate assessment and measurement of the stenosis. The findings of operative and virtual endoscopy were concordant in 9 cases. We conclude that surface modeling provides valuable information for preoperative evaluation of laryngotracheal narrowing. The ability to assess extraluminal anatomy provides a clearer picture of overall disease involvement. In the future, virtual endoscopy will probably be used in conjunction with operative endoscopy for therapeutic decision-making. Noninvasive virtual endoscopy could become an alternative to traditional endoscopy under general anesthesia for therapeutic follow-up.

Adolescent↗

PubMed2004

Escape behavior and escape circuit activation in juvenile crayfish during prey-predator interactions.

The neural systems that control escape behavior have been studied intensively in several animals, including mollusks, fish and crayfish. Surprisingly little is known, however, about the activation and the utilization of escape circuits during prey-predator interactions. To complement the physiological and anatomical studies with a necessary behavioral equivalent, we investigated encounters between juvenile crayfish and large dragonfly nymphs in freely behaving animals using a combination of high-speed video-recordings and measurements of electric field potentials. During attacks, dragonfly nymphs rapidly extended their labium, equipped with short, sharp palps, to capture small crayfish. Crayfish responded to the tactile stimulus by activating neural escape circuits to generate tail-flips directed away from the predator. Tail-flips were the sole defense mechanism in response to an attack and every single strike was answered by tail-flip escape behavior. Crayfish used all three known types of escape tail-flips during the interactions with the dragonfly nymphs. Tail-flips generated by activity in the giant neurons were predominantly observed to trigger the initial escape responses to an attack, but non-giant mediated tail-flips were often generated to attempt escape after capture. Attacks to the front of the crayfish triggered tail-flips mediated either by the medial giant neuron or by non-giant circuitry, whereas attacks to the rear always elicited tail-flips mediated by the lateral giant neuron. Overall, tail flipping was found to be a successful behavior in preventing predation, and only a small percentage of crayfish were killed and consumed.

Action Potentials↗

PubMed1989

The extracellular matrix modulates the response of PC12 cells to nerve growth factor: cell aggregation versus neurite outgrowth on 3-dimensional laminin substrata.

PC12 cells attach well to plastic culture dishes coated with laminin, collagen, polylysine or a basement membrane extract (2-dimensional substrata) and, in the presence of NGF, extend short neurites within 1-2 days. However, on gels (3-dimensional substrata) reconstituted from a basement membrane extract (RBM), PC12 cells attach extending short processes transiently and within one day, form networks of small aggregates interconnected by process-bearing cells. By 3 days the network collapses into large aggregates that, in media supplemented with NGF, extended a halo of neurites resembling dorsal root ganglia in culture. Time-lapse video recordings indicate that cell motility on RBM gel is accompanied by extensive blebbing as well as extension of processes that attach to and pull together neighbouring cells. These cellular events may contribute to the disruption of the gel underneath aggregates that is apparent when cultures are stained with Coomasie Blue. Ultrastructural studies indicated that aggregates often have zonula adherens-type junctions where cell bodies and processes come in contact. PC12 cells seeded onto gels of laminin alone behave essentially the same as on RBM gels, whereas on collagen gels they behave as on 2-dimensional substrata and extended neurites rather than aggregate. The extent of aggregation increases with greater cell density and is enhanced significantly by NGF. Antisera to NGF reduce the NGF-enhancement of aggregation but do not block aggregation in the absence of NGF. Dibutyryl cAMP or epidermal growth factor, which stimulate process extension and cell division respectively, do not enhance aggregation. However, 3A3, a monoclonal antibody to a laminin/collagen receptor on PC12 cells and antibodies (Fab fragments) to the neural cell adhesion molecule both inhibit cell aggregation.

Antibodies↗

PubMed1997

Immediate 8% sevoflurane induction in children: a comparison with incremental sevoflurane and incremental halothane.

We compared the efficacy and tolerance of pediatric inductions with immediate 8% sevoflurane in 70% nitrous oxide with either incremental sevoflurane or incremental halothane in 70% nitrous oxide. Forty-six unpremedicated children had anesthesia induced by immediate 8% sevoflurane (high sevoflurane [HS]; circuit primed with 70% N2O and 8% sevoflurane before application of the face mask), gradual sevoflurane (GS; primed with 70% N2O with increments of sevoflurane), and gradual halothane (HAL; 70% N2O with incremental halothane). Blind video recordings were made, and each child's distress was rated prior to mask application, during mask application, and every 10 s thereafter using a behavioral rating scale. There were no complications. Of those subjects not quiet and cooperative throughout, times to complete quiet were significantly different (P = 0.001): HS 19.8 +/- 8 s (range 9-34); GS 52 +/- 17 s (range 8-73); HAL 43 +/- 22 s (range 13-73). Times to eye closure were also significantly different (P < 0.001): HS 37 +/- 10 s (range 15-56); GS 70 +/- 18 s (range 35-114); HAL 81 +/- 34 s (range 55-140). Distress scale scores showed more rapid decrement with HS than with GS or HAL. We conclude that 1) immediate 8% sevoflurane/N2O results in a significantly faster induction than GS or HAL;2) in children, HS in N2O will not result in a single-breath induction under the conditions of this study; 3) in this small group, HS was extremely well tolerated in ASA class I and II patients.

Anesthesia, Closed-Circuit↗

PubMed2005

Visual and statistical modeling of facial movement in patients with cleft lip and palate.

OBJECTIVE: To analyze and display facial movement data from noncleft subjects and from patients with cleft lip and palate by using a new dynamic approach. The hypothesis was that there are differences in facial movement between the patients with cleft lip and palate and the noncleft subjects. SETTING: Subjects were recruited from the University of North Carolina School of Dentistry Orthodontic and Craniofacial Clinics. PATIENTS, PARTICIPANTS: Sixteen patients with cleft lip and palate and eight noncleft "control" subjects. INTERVENTIONS: Video recordings and measurements in three dimensions of facial movement. MAIN OUTCOME MEASURES: Principal component (PC) scores for each of six animations or movements and dynamic modeling of mean animations. STATISTICS: Multivariate statistics were used to test for significant differences in the PC mean scores between the patient groups and the noncleft groups. RESULTS: No statistically significant differences were found in PC mean scores between the patient groups and the noncleft groups; however, the variability of the effect of clefting on the soft tissues during animation was noted when the noncleft data were used to establish a "normal" scale of movement. Compensatory movements were seen in some of the patients with cleft lip and palate, and the compensation was not unidirectional. CONCLUSION: Measures of mean movement differences as summarized by PC scores between patients with cleft lip and palate and noncleft subjects may be misleading because of extreme variations about the mean in the patient group that may neutralize group differences. It may be more appropriate to compare patients to a noncleft normal scale of movement.

Adolescent↗

PubMed2003

Role of maxilla 2 and its setae during feeding in the shrimp Palaemon adspersus (Crustacea: Decapoda).

The movements of the basis of maxilla 2 in Palaemon adspersus were examined using macro-video recordings, and the morphology of its setae was examined using both scanning and transmission electron microscopy. The basis of maxilla 2 performs stereotypical movements in the latero-medial plane and gently touches the food with a frequency of 3-5 Hz. The medial rim of the basis of maxilla 2 carries three types of seta. Type 1 is serrate, type 2 and 3 are serrulate, and type 2 has a prominent terminal pore. Type 2 is innervated by 18-25 sensory cells whose cilia protrude through the terminal pore and are in direct contact with the external environment. The structure of type 2 setae indicates that they are mainly gustatory, although still bimodal due to their innervation by presumed chemosensory and mechanosensory neurons. Distally, the three types of setae have a complex arrangement of the cuticle involving water-filled canals, which may serve to improve flexibility. Type 1 and 3 setae have fewer sensory cells (4-9) but probably also have a bimodal sensory function. The function of type 1 setae is probably to protect type 2 setae, while type 3 setae might serve to groom the ventral side of the basis of maxilla 1.

Animal Structures↗

PubMed2006

A laboratory study on anticipatory movement in laparoscopic surgery: a behavioral indicator for team collaboration.

BACKGROUND: To assess team collaboration in the context of laparoscopic surgery, laparoscopic cutting tasks performed by single operators and dyad teams were observed. Our previous work suggested that the anticipatory movement performed by a teammate may lead to a shorter total task time than for a single bimanual operator. This report further explores this phenomenon by quantifying the frequency of anticipatory movements and discussing their significance to team collaboration. METHODS: Subjects were required to reach, grasp, and cut a piece of thread using a laparoscopic grasper and scissors. The task was performed by either 8 individual subjects bimanually or 16 paired subjects unimanually (using their preferred hands). The performances were video recorded. The total task time, the time used for thread grasping and cutting, and the number of anticipatory movements were computed and compared between the single operator and the dyad team group. In this report, anticipatory movement is defined as movements of the scissors before the completion of grasping and holding the thread. RESULTS: Shorter durations of total task time were shown for the dyad than for the bimanual group. Anticipatory movements were counted significantly more often when the scissors were controlled by a teammate on the dyad team (96%) than when they were controlled by the preferred hand of the operator (45%). The number of anticipatory movements increased with practice, but no significant difference was shown among practice phases. CONCLUSION: Higher frequency of anticipatory movement was observed in the dyad team, which led to superior performance for team collaboration, as compared with that of the single operator. Performance of anticipatory movements in the dyad team was explained by a shared mental model, which postulates combined capacity for information processing among team members. Results have implications for surgical education, team training, and error prevention in the performance of laparoscopic surgery.

Adult↗