In orthopedic surgery, surgeons have to handle not only bone but also the surrounding soft tissue, including muscle, fascia, tendon, ligament and capsule. Successful handling of these tissues is often the key to high reproducibility, good soft tissue healing, and restoration of overall function. However, there are no widely used, robust methods for intra-operatively quantifying soft tissue tension, an important variable in healing and overall limb alignment. Established methods require violation of the soft-tissue (e.g. buckle transducer), access to a free end of the tissue (e.g. graft tensioner) or knowledge of indentation distance. Current commercial products are limited to the knee, are not handheld, are invasive, and measure force or load, but not tension. There are no simple, non-invasive, inexpensive handheld devices available allowing to reliably and accurately quantify soft tissue tension for orthopedic surgeries. Such devices are needed to quantify tactile feedback ("feel") to measure and adjust tension of various structures in open surgeries, and importantly overcome the limited tactile feedback in arthroscopic surgeries. Optimizing and quantifying tension is important for various procedure outcomes of orthopedic surgeries, with possible applications beyond orthopedic surgery (i.e. physical therapy, plastic surgery, general surgery). Aside from using such a tool in routine surgeries, such a tool would also have applications as clinical instrument for training and recertification, as well as a research device to study outcomes in a broad range of orthopedic, plastic, and possibly other surgical procedures. To evaluate whether a hand held sensor concept is feasible, a handheld tissue tensioning sensor prototype was developed and validated. The sensor consists of three cylindrical pistons that move in slots in a plastic housing Bearings in the slots are used to eliminate friction. While the preliminary results with this senso are encouraging, the sensor is significantly too large for any clinical and commercial application. Therefore, in this phase 1 application, we will carry out the development of a miniaturized sensor probe, with subsequent rigorous biomechanical calibration and validation of the sensor function in synthetic and vertebrate ligament tissues. This effort will pave the way for a Phase 2 application to develop an entire handheld sensor device with integrated handle, and validate the sensor device function in a clinical study.
There is a need to quantify tension to study and optimize various procedure outcomes of major orthopedic surgeries including arthroscopic surgeries. Such device also has utility for surgeon's training and recertification, as well as a research tool to study outcomes. While invasive non-handheld devices to measure tension or load are commercially available, to date, no handheld, non-invasive, inexpensive and easy-to-use tension sensing devices are available to the orthopedic surgeons. To this end, FocusStart is developing a handheld tissue tension sensor probe that it will miniaturize and validate in this phase 1 SBIR grant.