Increased abdominal pressure is thought to contribute to abdominal hernias, pelvic organ prolapse, urinary incontinence and surgical failure of these conditions. Whether or not this is true is entirely untested; however, based on this conventional wisdom, surgeons commonly recommend to patients substantial restrictions, often long-term, in activities after such surgeries. Women are doing more strenuous activities, both recreationally and in the workplace , and the degree to which this might impact abdominal wall and pelvic floor support is unknown.
Understanding the association between physical activity and hernias or pelvic floor disorders is hampered by lack of instruments with which to assess strenuous activities that raise intra-abdominal pressure.
Intra-abdominal pressure is routinely measured in the urodynamics laboratory, as comparing the intra-abdominal pressure with the bladder pressure is an integral part of this clinical study (generally performed as part of the evaluation for urinary problems). The pressures in either the upper vagina or the rectum have been shown to correlate well with true intra-abdominal pressure.
We recently studied intra-abdominal pressures during some common activities that could be done in the urodynamics laboratory (such as position changes, lifting various loads and walking on a treadmill), by means of microtip rectal pressure transducers inserted into the upper rectum which were connected via a long catheter to the urodynamics machine. In this study, we found that some activities that are commonly prohibited after surgery (like lifting 10-20 pounds) raised the pressure less than activities done many times a day and not proscribed (like getting out of a chair).
This study provided a foundation for understanding the range of pressures during certain activities but was limited by the necessarily artificial setting. We were only able to study women for a short time and only those activities that could be done while they were tethered to a machine.
Our ultimate aim is to understand the effect of different types of activities on abdominal pressure in the real world. However, there is currently no instrument to accomplish this. Therefore, we plan to develop a vaginal transducer that will transmit pressure information remotely.
The sensor will have the ability measure both force and pressure in a non-fluid filled environment. This will allow for non-invasive monitoring of intra-abdominal pressures via the vagina. The ultimate goal of this pilot study will to be to spark further research investigating the causes of pelvic floor dysfunction.
Our interdisciplinary research team has met regularly, thoroughly discussed design and any safety issues, and have undertaken the preliminary work outlined in the Protocol Summary to develop the device which we plan to test in this proposal.
Study A: The aim of this pilot study is to test each version of the vaginal pressure prototype in adult women undergoing urodynamic testing. The 3 versions of the prototype (and thus 3 steps of this pilot study) are:
1) Prototype 1 is tethered to the urodynamics machine,
2) Prototype 2 is wired to a portable data acquisition monitor, and
3) Prototype 3 is completely independent of leads and pressure data are transmitted remotely.
Note that the vaginal sensor device is the same for all three steps; only the way in which the data are transmitted will differ.
For each step, results from the prototype will be compared to the gold standard of abdominal pressure measured during standard urodynamics testing via a rectal catheter.
Study B: In addition, we will conduct an “Insertion and Retention” substudy. The aim of this substudy is to determine whether our prototype sensor device is easy to insert by women and whether it stays in place during strenuous activities. Women enrolled in this substudy will NOT be those undergoing standard urodynamics but rather will be recruited from flyers and the PEAK academy (described in more detail below). We have developed a separate consent document for women in this substudy.
Study C: A small number of women (between 1-5) will wear a version of the sensor while doing a prescribed exercise session in the Human Performance Lab. This will provide us with raw data which we will scrutinize the data at a later time to plan how we will collect and analyze data as we develop the wireless version of the sensor. A separate consent document has also been developed for women in this substudy.