Testing and introduction of new materials - Orthopaedic Biomaterials in Research and Practice - page 379

User
needs

Review

Design
input

Design
process

Design
output

Verification

Requirements
are fulfilled

Medical
device

Validation

Intended use
is fulfilled

FIGUre 15.2 (See color insert.) the waterfall model for the design
process.

been described above. This process involves the development of require-
ments and designing a material or device to meet those requirements.
After the material or device has been assessed, it is then transferred
to manufacturing. This process is iterative because there are feedback
loops throughout the process, as well as evaluations by a review team to
ensure that each step is performed sufficiently to avoid delays in the pro-
cess and to limit the chance that a material or device may be developed
without meeting its intended use.
Two of the key components of design controls are document con-
trol and change control. Document control relates to enumeration of
design documents and tracking of their status and revision history. It
also includes maintenance of a document index and history of document
revisions. Change control involves documenting decisions for design
change requests and identification of the possible design matter that
the requester believes should be corrected. Any acceptances of changes
should be documented, along with any assignment to members of the
design team to further evaluate the change request and review the impact
of the design change on the design inputs and intended uses.
Since the design cycle is an involved process, involving many design
considerations and decisions, it is important to establish and maintain a
design history file , which is a compilation of records that describe the
design history of the finished product. This includes documentation that
is necessary to demonstrate that the design was developed in accordance
with the design plan and CFR 820 requirements. This tells the story of
design development process from beginning to end, in a chronological
order, providing a permanent record of the knowledge base. This is espe-
cially helpful when key employees leave or if the company reorganizes,
and so on. All in all, the design history file contains the documentation
necessary to assure that any changes to the device design or manufac-
turing process do not adversely affect the performance of the device,
ultimately leading to an improvement in the device design and process.