Laparoscopic intracorporal colorectal sutured anastomosis using the Radius Surgical System in a phantom model.

BACKGROUND: The Radius Surgical System (RSS) is a manipulator with additional degrees of freedom to enhance the dexterity of laparoscopic suturing. Our aim was to determine the feasibility and potentially added value of laparoscopic intracorporal sutured colorectal anastomosis (RSS) compared with suturing with conventional laparoscopic instruments (CLI). METHODS: A total of 72 colorectal anastomoses and 30 single sutures using RSS and CLI were performed in the study. The experiment was divided as follows: One surgeon performed 40 colorectal anastomoses using RSS to assess the learning curve and the feasibility of the technique; The same surgeon performed 10 additional colorectal anastomoses with CLI which were then compared to the last 10 cases of the 40 anastomoses with RSS; Fifteen single sutures in the horizontal plane with RSS and 15 with CLI between two segments of colon were performed to compare the traction force to disrupt the suture; Twelve anastomoses were performed by the other three participants to evaluate ergonomy. RESULTS: Three leakages (7.5%) were found in the 40 anastomoses with RSS but none after the eighth case. There was no stenosis. The mean time for the anastomoses once the learning curve was achieved was 32.7 min. After 21 anastomoses with RSS there was no improvement in the operating time. The quality of the suture was superior with RSS, with a larger anastomosis diameter, higher bursting pressure, and fewer suturing failures being found. The RSS suture withstood a higher traction force. The participants showed more discomfort suturing with CLI. CONCLUSION: This study demonstrated the feasibility of laparoscopic colorectal anastomosis using RSS. Anastomosis with RSS was shown to be safer. The three participants evaluating ergonomy reflected less discomfort in hand/wrist using RSS. Others ergonomic problems were comparable to CLI.

Ergonomics with the use of curved versus straight laparoscopic graspers during rectosigmoid resection: results of a multiprofile comparative study.

BACKGROUND: A detailed ergonomic comparison of motions and muscular activity in the left upper extremity using a laparoscopic straight or curved grasper in rectosigmoid resection is presented. METHODS: The study had two parts: experimental and clinical. In the experiment part, 30 laparoscopic sigmoid resections were performed under animal organ phantom conditions. The operations were divided into three groups according to instrument and trocar position. Group 1 (n = 10) underwent operations performed with a curved grasper in the excentral trocar position (in relation to the telescope trocar), with the left-hand curved grasper placed in the right flank and the right hand instrument in the right lower quadrant. In group 2 (n = 10), straight forceps were used in the excentral trocar position. Group 3 (n = 10) underwent laparoscopic sigmoid resection performed with a straight grasper in the central position (in relation to the telescope trocar), with the instruments placed at both sides of the lower abdomen. To measure ergonomic aspects during rectosigmoid resection, several overview video cameras, surface electromyography (EMG), an ultrasound tracking system (UTS), and a questionnaire were used. In the clinical part of the study, laparoscopic rectosigmoid resections (n = 5) were performed using a curved instrument in the excentral trocar position. The surgeon's left-hand movement and body posture were recorded for further analysis. RESULTS: The curved grasper required the fewest contractions (group 1) of the measured muscles. A comparison of the UTS analysis in the experimental part of the study and the video analysis in the clinical part showed economy of movements in group 1. According to subjective estimation, both physical activity and mental stress remain at the lowest level when the excentral trocar position is used (groups 1 and 2). CONCLUSIONS: The combination of the curved grasper and the excentral trocar position (in relation to the telescope trocar) is, according to our examinations, the best ergonomic adjustment for laparoscopic rectosigmoid surgery.

Study of ethidium bromide interaction peculiarities with DNA.

The helix-coil transition of DNA-ethidium bromide complexes in an interval of ionic strength of 2.0 x 10(-3) M < or = muNa+ < or = 2.0 x 10(-2) M has been investigated. It has been revealed that at the certain high ligand-DNA ratios (r(b)) the transition interval of the complex--(deltaT) becomes equal to that of DNA itself (deltaTo). It has been shown that the values of r(b) at which delta deltaT=deltaT-deltaT0=0 depends on ionic strength of a solution. Further increasing of ligand concentration leads to its conversion from stabilizer into the destabilizer of the double-stranded DNA.