insights
Introduction
A medical device concept can look great in CAD and still leave important questions unanswered. Does it feel right in the hand? Does it fit the anatomy the way you expected? Can the intended user manipulate it comfortably? Are the interfaces, clearances, and mechanical relationships practical once the design becomes physical?
These are the kinds of questions that are difficult to answer from a screen alone, and they are exactly why prototyping often begins during Phase 0.
At Kapstone Medical, Phase 0 is where we take an early concept and challenge the assumptions behind it before a company commits significant time and capital to formal development. Depending on the project, that may include engineering, regulatory, intellectual property, manufacturability, and market considerations. Prototyping fits naturally into that process because it gives the team something tangible to evaluate. A concept that previously existed as a sketch or CAD model becomes a physical object that can be handled, tested, critiqued, and improved.
Key Takeaways:
- Early prototyping helps evaluate form, fit, function, ergonomics, and design assumptions before a full development program begins.
- Additive manufacturing is well suited to feasibility work because it supports low quantities, rapid iteration, complex geometry, and no hard tooling.
- Physical prototypes often produce better clinician and user feedback than digital models alone.
- Design problems identified during feasibility are generally easier and less expensive to correct than issues found after design freeze, verification, or tooling.
- The most useful prototype is not necessarily the most polished one. It is the one that answers the right development question at the right time.
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Where Prototyping Fits in Phase 0
A Phase 0 Feasibility Study is an early multidisciplinary evaluation of a medical device concept. We have written previously about how this approach can help mitigate risk and control upfront cost and move a concept from sketch to roadmap.
Within that work, a prototype becomes one of the most useful technical tools available. A CAD model can support analysis and design review, but a physical prototype introduces a different category of information. Once the concept exists in three dimensions, the team can start challenging assumptions that may otherwise remain hidden.
The purpose of an early prototype is not to create a finished or production-ready medical device. It is to learn. The earlier a team can identify a design problem, interface issue, ergonomic concern, or manufacturability challenge, the easier and less expensive it is to address. Discovering the same problem after design freeze, tooling, verification planning, or supplier qualification can create significantly more rework.
What an Early Prototype Can Reveal
Some of the most useful findings from early prototyping are straightforward, but difficult to get from CAD alone.
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Clinical and user feedback. A clinician can often provide more meaningful input when holding a representative device than when reviewing a rendering. Grip, reach, orientation, visibility, access, and procedural workflow become easier to evaluate physically.
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Form and fit issues. Physical parts can reveal interference, insufficient clearance, awkward assembly, unrealistic tolerances, or geometry that complicates use or manufacturing.
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Design tradeoffs. When several mechanisms or geometries are under consideration, building multiple versions can make the differences much easier to understand.
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Early design risk. Problems identified during feasibility can often be addressed with a CAD revision and another prototype rather than affecting later-stage verification, tooling, or supplier work.
This does not replace formal human factors engineering, verification, validation, or design controls. It simply improves the quality of the decisions made before those later activities begin.
Why Additive Manufacturing Works So Well in Early Medical Device Development
Additive manufacturing aligns closely with the needs of feasibility-stage development because Phase 0 is usually about learning, not volume production.
There is no need to invest in hard tooling for a design that may change after the first review. One-off parts and small quantities are practical. Iteration can happen quickly. And complex geometries can often be produced without simplifying the design purely for the sake of prototyping.
That combination is especially valuable in medical devices, where geometry may be driven by anatomy, procedural access, mechanical constraints, or the need to combine several functions in a small space.
The method we choose depends on what we are trying to learn:
- Polymer additive manufacturing is often ideal for ergonomics, form, fit, handling, anatomical interaction, and early clinician feedback.
- Metal additive manufacturing becomes more useful when the team needs a mechanically representative part for surgical instruments, orthopedic components, fixation systems, or structural testing.
- Multiple prototype iterations may be appropriate when the team is comparing alternative mechanisms, interfaces, or architectures before selecting a direction.
Why This Matters in Orthopedics
Orthopedic devices are a particularly strong fit for additive manufacturing during early feasibility. Implants, fixation systems, and surgical instruments often involve complex interfaces, tight tolerances, and anatomy-driven geometry that can be difficult to fully appreciate in CAD.
Putting a representative part in a surgeon’s hands early can change the conversation immediately. A surgeon may notice an access issue, grip problem, anatomical interference, or procedural limitation that would have been difficult to identify from a rendering alone.
A physical prototype can help the team evaluate:
- anatomical fit;
- instrument access;
- implant positioning;
- handling and ergonomics;
- interface geometry;
- procedural workflow; and
- potential manufacturing challenges.
That feedback can then be incorporated while the design is still flexible and relatively inexpensive to change.
A Concept Made Real
We see this regularly in Phase 0 programs.
In one recent orthopedic project, a surgeon-inventor came to Kapstone with a concept based on a problem encountered in clinical practice. The initial design could be reviewed digitally, but there were still practical questions around how the device would interact with the anatomy and how the surgeon would use it during the procedure.
During feasibility, the team produced 3D-printed prototypes so the inventor could physically evaluate the concept. That interaction generated better feedback than a rendering alone could provide. The inventor was able to assess the geometry in context, identify areas for refinement, and develop a clearer understanding of the path forward before committing to a larger development effort.
The prototype did not prove the design was complete. It gave the team better information.
A Prototype Is Not the Same as a Development Strategy
Today, it is relatively easy to send a CAD file to a prototyping service and receive a printed part. That does not necessarily mean the design is feasible as a regulated medical device.
A useful prototype has to be interpreted within the broader development context. The team still needs to ask questions such as:
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Does the design align with the anticipated regulatory pathway?
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Are the materials appropriate for the intended use?
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Can the geometry eventually be manufactured consistently?
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Does the design create cleaning, sterilization, or reprocessing challenges?
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Are there intellectual property considerations?
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What testing will eventually be required?
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Does the added design complexity create enough clinical or commercial value to justify it?
This is where an integrated Phase 0 study becomes especially valuable. The prototype is not treated as a standalone deliverable. It becomes one piece of evidence within a larger feasibility assessment.
Engineering may identify a mechanical issue. Regulatory may determine that a certain feature changes the likely testing burden. Manufacturing may identify a geometry that is difficult to produce consistently. Market analysis may raise questions about whether the complexity is justified by the value proposition. Those perspectives together are what help turn an early idea into a more defensible development plan.
From Prototype to a Defensible Development Roadmap
A strong Phase 0 study should leave the team with a clearer understanding of what the product is, whether the concept appears technically feasible, what major risks remain, what regulatory pathway is likely, what manufacturing challenges need to be solved, and what the next development phase should include.
For startups and clinician-inventors, that physical evidence can also support fundraising and strategic discussions. A prototype backed by a multidisciplinary feasibility assessment tells a different story than a sketch or rendering alone. It shows that the concept has progressed beyond an idea and that important technical, regulatory, and manufacturing questions are beginning to be understood.
We discuss that relationship further in How Feasibility Studies Help Medical Device Startups Get Funding.
The strongest prototype is not necessarily the most polished one. In early development, the best prototype is the one that answers the right question early enough to influence the design.
That is why prototyping often starts in Phase 0. It turns assumptions into something the team can challenge, gives clinicians and engineers better information to work with, and helps identify problems while they are still relatively inexpensive to solve.
Additive manufacturing makes that process faster and more practical, but the real value comes from integrating the prototype into a broader feasibility strategy.
Hayden Kapitan is Director of Business Development at Kapstone Medical, a medical device development consultancy and contract manufacturer supporting engineering, regulatory, quality, and manufacturing programs. To discuss a Phase 0 Feasibility Study for a new medical device concept, start a project with the Kapstone team.
Frequently Asked Questions: Understanding Phase 0 Feasibility
What role does prototyping play in Phase 0 feasibility?
Prototyping helps convert an early concept into a physical part that can be evaluated for form, fit, function, handling, and design risk. It gives engineers, clinicians, and inventors better information before they commit to a full development program.
Why is additive manufacturing a good fit for early-stage medical device development?
Additive manufacturing does not require hard tooling, supports low-volume production, allows complex geometry, and makes design iteration relatively fast. Those characteristics make it especially useful when the design is still evolving.
Does a Phase 0 prototype need to be fully functional?
No. The right prototype depends on the question being asked. A simple polymer model may be enough to evaluate form, fit, anatomy, or ergonomics, while a more functional prototype may be appropriate when the team needs to investigate a mechanism or perform early benchtop testing.
Is a 3D-printed prototype production ready?
Not necessarily. A feasibility prototype may use different materials, tolerances, finishes, or manufacturing methods than the final commercial device. Unless specifically addressed, it should not be assumed to represent a validated, verified, sterilizable, or production-ready product.
