TABLE 1.
List of sensor requirements for MIS tactile sensing.
| Category | Requirement | Description |
|---|---|---|
| Operational requirements | Sensitivity | Produce accurate data with at least 0.2 N sensitivity for MIS (Lazeroms et al., 1996) |
| Dynamic range | Typical medical forces range between ±10 N, laparoscopic surgical tools apply forces between 0 and 25 N but can go as high as 40 N (Kalantari et al., 2010) | |
| Frequency | Typical laparoscopic grasping frequencies do not exceed 3 Hz (Sarmah and Gulhane, 2010) | |
| Repeatability/linearity | Produce repeatable, precise data without drift and hysteresis error in differing environments | |
| Dexterity | Cannot sacrifice or interfere with surgeon dexterity (by being too bulky, fragile, rigid) | |
| Response rate | Provide rapid, on-the-fly measurements (within 1 millisecond) (Yousef et al., 2011) | |
| Hardware requirements | Miniaturization | Needs to fit within laparoscopic width of 5–8 mm in a typical MIS tool |
| Reliability | Robust, functional through entire surgical operation, reducing moving parts in sensor usually increases reliability | |
| Waterproofing | Needs to be resistant in bodily environments of bodily fluids, organs, and soft tissues | |
| Compatible with MIS tools | Cannot interfere and be interfered with the operation of endoscopes, catheters etc. | |
| Sterilizable | Needs to be easily sterilizable for MIS to avoid contamination of infection (needs to be stable in acidic and basic sterilizing environments) | |
| External requirements | Cost | Laparoscopic tools are thrown out after each operation, so they need to be disposable and affordable |
| Assembly | Needs to be easily assembled and integrated within a wide range of MIS models and tools, will also become beneficial for mass production purposes | |
| Recommended requirements | Working area | Wide working area to allow force measurement across a laparoscopic grasper or tool |
| Compliance measurements | Measurement of hardness and softness of tissues through the force sensor | |
| Force identification | Differentiation between normal and shear forces helps with tissue characterization, surface friction, viscosity (Yousef et al., 2011) | |
| Temporal variation | Differentiate between dynamic and static forces, measure both accurately (Yousef et al., 2011) |