To position the new interface credibly, the team benchmarked six comparable surgical devices that combine mechanical power with embedded interfaces. These included ultrasonic tools, powered saws and other high speed instruments used in orthopaedic and trauma surgery. The objective was to understand how the best devices handle state feedback, error messaging and control grouping, and also where they fail.

The benchmarking focused on practical aspects rather than visual style. It examined how quickly a surgeon could verify readiness, how consistently warnings were presented, how mode changes were reflected, and how well the devices supported preparation, use and post use cleaning phases. Some interfaces relied too heavily on colour, which becomes unreliable under operating theatre lighting and across different monitors. Others compressed too much information into small areas, leading to extended visual search times. In several cases consumable handling and cartridge status were underrepresented despite their role in safe operation.

By comparing these patterns with the emerging architecture for the ultrasonic cutter, the team identified opportunities to improve on common weaknesses. For example, by combining redundant cues for state indication rather than relying on colour alone, or by grouping all cartridge related information in a consistent area that remains visible during activation. This benchmarking work informed decisions that made the new surgical tool UI recognisably part of the medical device category while also addressing long standing frustrations that surgeons reported with existing equipment.

The ultrasonic cutter is first a physical instrument. The surgeon experiences the device through the handpiece, the mechanical response during cutting, the cartridge system and the physical controls on the console. The embedded GUI is one element in this chain, not a separate product. Effective medical device UX design for this kind of instrument must therefore treat physical and digital parts as one system.

Surgeons interact with the display using the non dominant hand, often while holding other tools and maintaining a stable position relative to the patient. Reachable zones on the screen are constrained by arm position, draping and sterile field boundaries. Gloved hands reduce precision and tactile feedback. For this reason the interface avoids small targets or controls placed at extreme corners. Interaction paths are kept short and concentrated in areas that match realistic reach envelopes.

The console includes physical buttons for essential actions and slots for cartridges. These elements were mapped against on screen controls so that state changes are always reflected both mechanically and graphically. For instance, when a new cartridge is inserted and locked in place, the display confirms the type and readiness in a consistent region with clear iconography and text. This integration of physical and digital behaviour reduces the risk of misinterpretation and supports safe use in the operating room, where sterile handling and device cleaning practices also limit unnecessary contact with the display.

Human factors engineering was not treated as a separate activity. It formed part of every design decision. The twelve research studies reviewed at the beginning of the project continued to guide detailed work. Findings on touch performance with gloved hands influenced minimum control sizes and spacing. Research on dual task performance and attention switching helped determine how much information could be presented without overwhelming the user at critical moments. Visual perception literature informed choices on contrast, grouping and the use of colour.

For example, evidence shows that users under time pressure and with divided attention rely primarily on spatial patterns and consistent icon forms rather than on text. The interface therefore adopted stable layouts where the relative position of key indicators never changes between screens. Colour was used to reinforce rather than replace these patterns, which mitigates variability in lighting and display characteristics. Feedback timing for state changes, such as reaching a safe speed range, was aligned with findings on reaction times and confirmation delays in complex tasks.

These principles were presented to the product owner, engineers and clinical representatives in a clear and practical way. Instead of abstract theory, the team explained how each principle addressed a specific use-related risk identified in the requirements catalogue. This created a shared understanding that helped the steering committee evaluate trade offs and provided a documented rationale that can support regulatory submissions and future medical device human factors reviews.

With the requirements, architecture and human factors foundations in place, the team progressed through a series of iterative design cycles during Concept Convergence. The first cycles focused on low fidelity sketches that explored different layouts within the chosen structural model. Later cycles refined interaction details and edge cases in higher fidelity wireframes. Throughout, the emphasis remained on clarity for surgeons and robustness for engineers implementing the embedded medical software.

Thirteen structured review sessions involved the core client team and subject matter experts. In each session the team worked through representative scenarios, including initial setup, cartridge changes, speed adjustment during use, response to warnings and preparation for cleaning. Comments were captured directly on the wireframes, which made questions about feasibility, safety and clinical relevance visible to all disciplines.

The two week steering meetings provided a formal governance rhythm. At these sessions the team presented the evolution of the surgical user interface, the impact of new findings, and the rationale for key decisions. Clinical preferences, regulatory interpretations and engineering constraints could be reconciled while maintaining momentum. This process supported transparency, which is particularly important for complex workflows in regulated environments, and ensured that the emerging design remained acceptable for all critical stakeholders.