Samenvatting

Over a period of 5 years (2006-2010) there was an increase of more than 600% in performed hip arthroscopies. During hip arthroscopy a perineal post is placed between the legs, to counter the generated pulling force and to make sure the patient stays in position. Due to this dislocation procedure several complications can occur. The most occurring complication is the pinching of the pudendal nerve. This pinching can lead to months of nerve failure. Therefore a redesign of this perineal post was made to reduction of this complication.
Different conclusions have been made from the analysis phase. At the current perineal post the pressure is mostly located at the perineal area, instead of the tuberculum ischiadicae. The main goal of the redesign of the perineal post was a reduction of at least 20% of the pressure distribution at the perineal area.
With the help of the analysis phase the list of requirements was set up. With those requirements in mind many sketches were drawn and four concepts were selected. The ideas ranged from a beanbag to a saddle concept. With a cardinal method the best concept was chosen; the saddle concept was the most progressive and was redesigned and improved. Mock-up models were made from the four selected concepts to visualize the function of each concept. With the help of the mock-up models the final concept was chosen: ‘the improved saddle concept’.
The final design was manufactured as proof of concept and was subsequently tested on seven subjects. To this end and operation look-a-like setting was built. A pressure mat was placed between the subjects, and both perineal posts, to visualize the pressure. Both perineal posts were randomly tested for all subjects.
The redesigned perineal post reduced the pressure distribution at the perineal area with 83%. The pressure distribution at the tuberculum ischiadicum of the operated leg, increased with 30%. However, the pressure distribution at the tuberculum ischiadicum of the non-operated leg, decreased with 16%. The mean maximum pressure increased with 28%. Finally, the preferences of the subjects were noted as well. The females preferred the redesigned perineal post (five female subjects), and the male subjects did not have a preference (two male subjects).
The goal of the 20% reduction of the pressure distribution in the perineal area was achieved with the redesign of the perineal post. This goal was achieved as a pressure distribution reduction of 83% was achieved.
The redesign meets almost all the setup requirements, for example the redesign can be used for both left as right hip arthroscopy, and three different sizes have been designed.
The measurements were done by a operation room look-a-like setting, therefore more research has to be done to finalise the product, and a prototype should be made and tested in a OR setting.