Grasping soft tissue by means of vacuum technique.

INTRODUCTION: A notable characteristic of bariatric surgery is the frequent manipulation of the bowel. The bowel is large, delicate, flexible, and has a natural lubricant on the tissue surface. Therefore the bowel is difficult to grasp and manipulate. Vacuum technique is commonly used in industry for all types of grasping and manipulation. Two types of nozzles that differed slightly in geometry (NT1 and NT2), were reviewed in an experimental set up for pull tests on pig bowels. MATERIALS AND METHODS: An experimental set-up was used to conduct a series of pull tests on pig bowel tissue. The basic principle of the measurements was a Newton's force balance; F(Pmax)=Δp×A. Student t-tests, two-way ANOVA and Wilcoxon signed rank tests were conducted for the statistical analysis of NT1 and NT2 with regard to the maximum pull force (F(Pmax)). RESULTS: Concerning NT1 the Newton's force balance could not be confirmed. Concerning NT2 the Newton's force balance could partly be confirmed. For both nozzle types the effect of Δp on F(Pmax) was significant. F(Pmax) increases linear in proportion as Δp increases. This relation between F(Pmax) and Δp was confirmed by the Newton's force balance. DISCUSSION: The results confirm that vacuum technique can be used as a grasp technique for soft organs, particularly the bowels. By means of a clever design of the nozzle a firm grip can be obtained on the bowel segments. Therefore vacuum technique should be studied for further development of instruments, graspers and retractors, to be used in the abdominal area.

Vacuum grasping as a manipulation technique for minimally invasive surgery.

BACKGROUND: Laparoscopic surgery requires specially designed instruments. Bowel tissue damage is considered one of the most serious forms of lesion, specifically perforation of the bowel. METHODS: An experimental setting was used to manipulate healthy pig bowel tissue via two vacuum instruments. During the experiments, two simple manipulations were performed for both prototypes by two experienced surgeons. Each manipulation was repeated 20 times for each prototype at a vacuum level of 60 kPa and 20 times for each prototype at a vacuum level of 20 kPa. All the manipulations were macroscopically assessed by two experienced surgeons in terms of damage to the bowel. RESULTS: In 160 observations, 63 ecchymoses were observed. All 63 ecchymoses were classified as not relevant and negligible. No serosa or seromuscular damages and no perforations were observed. CONCLUSION: Vacuum instruments such as the tested prototypes have the potential to be used as grasper instruments in minimally invasive surgery.