Out of the nine parts of design controls, planning has to be the most essential because this aligns the project to be successful. The design development plan includes a summary of the project, a timeline, a structure for meetings, and who is on this team. The most tedious, I would have to say, is design verification. Each output needs to be tested and recorded. If a test fails, that part goes back to be redesigned, and then needs to undergo testing again. This process repeats until everything passes.

I don't think there is one "essential" design control. Design control is an essential process that guidelines how to create a safe and effective medical device, so each step in the process is essential in achieving that. Each of the 9 plays an integral role in helping toe the line between progress and safety.

I think the most annoying design control depends on who you ask and what tasks you're asked to do. Being incredibly subjective, I personally find DHF the most annoying -- Maintaining incredibly accurate and intricate documentation of practically everything that gets done. That being said, I also understand that it is one of the most critical steps, as it's needed to gain FDA approval. 

I think in general, it is incredibly important to keep in mind that design control is a good thing. There may be some annoying or frustrating parts that come up while working in creating a medical device, however they are mandated for a reason: They make sure that devices that are going into peoples bodies are safe and effective and have been proven to work. As biomedical engineers, keeping the patient in mind and making safe devices should be the top priority and design control is an essential process in making sure that the things we create align with those priorities.

Thanks,

Matt 

As mentioned in the lecture there are nine design controls listed in 21 CFR 820.30 - these include: planning, input, output, review, verification, validation, transfer, design changes, and design history files. As stated by @mmd55, all nine parts are essential in the development of a safe and effective medical device, however, as Dr. Simon alluded to in his lecture they should also be adopted into all phases of the PDCA cycle and other medical device projects such as packaging, production, and distribution. Reading into these controls a bit more [1], I would say design input is the most essential of all the controls because that it is almost the starting point and the more concrete foundation you set in terms of product requirements and specifications, the more straightforward the other design control components will be. As for the most annoying to keep up with, I again would have to agree with @mmd55. The design of history file requires documenting a products evolution from beginning to end - including requirements, tests, changes, meetings, reviews, as well as procedures validating and verifying device design.

[1] https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm?fr=820.30

Design controls were created by the FDA in the late 1990s and its purpose is to make sure the product is in compliance with all the codes every step of the way. This means that every part of the project will have at least one document for it, and this will depend on the company as some might clump some parts with others while some companies might keep everything completely separate. It is important that these documents contain everything the FDA is looking for. The concept is divided into 9 different parts; planning, input, output, review, verification, validation, transfer, design changes, and design history file. Each of these parts plays a different but essential role in the design controls and in maintaining the FDA regulations. Of these 9 parts, the one that would be very "annoying," or repetitive, would be the design changes. It is very rare that the initial idea and the final design of a project will be the same and therefore the project will undergo many changes throughout its lifetime. The idea of the design changes in design control is that every change made to the design is logged and kept track of. Supporting documents need to be updated every time a change gets made and that can start becoming repetitive to do, especially if the project is constantly changing. Just because this step might be annoying, it does not make it any less crucial in the final design and is a good way to track how the idea has evolved during all the phases of making the idea into a real object.

I think all the nine steps(Design and development planning, Design input, Design output, Design review, Design verification, Design validation, Design transfer, Design changes & Design history file) are essential but the most important is Design Validation. Without design validation a medical device company can make any claims without proving the validity of those claims. This would go against what the FDA stands for. Design validation in not only necessary for the FDA also for the engineers to know what they have made is actually viable and functional.

All design controls tie into each other in some way so it's difficult to single out an "essential" design control. However, since the first 9 design controls serve as a basis whereas the actual content differs from company to company, I feel like it would make the most sense for the planning followed by the input and output to be the "essential" design control. This would serve as a proper strong foundation to build off of for the other design controls. With proper planning and the right input and output, reviewing, verifying, validating, transferring, etc. will all be easier to manage and be up to standard since the right principles were set.

As it has been said in almost every one of the previous posts, each of the nine design controls covered in Dr. Simon's lectures are essential in completing a successful project. However, I do think that the planning and input parts could be considered two of the most essential parts. Like it has been said already, the planning of the project lays the ground work for the rest of the project to follow. Proper planning at the earliest stages of a project's life will only make things easier later down the road, therefore, adequate planning is essential in starting a project. I also believe inputs are just as essential as planning, as the inputs are what was asked for and needs to be completed to fulfill the project. At the same time, the planning stage can also be the most tedious of the design controls, as it is extremely hard to properly predict everything that will happen through out the stages of the project. Documents such as the Project Proposal, Design Development Plan, and Design Input Documents are all documents meant to help to plan out the project thoroughly. Although the future is impossible to predict, these documents are meant to help plan the rest of the project to ensure a smooth and successful end product.

As many people have mentioned throughout this discussion, I do believe that there is not one essential design control that trumps the others. As @ama224 mentioned, each design control feeds into one another and every design control is based off of the previous in the list of the nine parts. With this type of thinking I would have to say that the first part of the nine, the planning part would be the most crucial since everything starts with the planning. If there are inconsistencies in the planning step, this could cause issues in other parts down the line and could lead to the project entirely failing or having to go back to the planning part and revise the project plan. By having to go back to the planning step this could cause a loss of funds, time, and resources which would be detrimental towards the entire project. The planning step should include the scope of the project and should address basic timelines, resources, and customer need. If there are any errors in the overall idea of the project where it may not be profitable due to the market that it is competing in, a total loss could occur. For this particular reason I would say that the planning would be the most crucial step to answer your question. In terms of annoying to keep up with I would say design changes just because the project is bound to undergo several design changes and if the team has not been logging documents and changes in a centralized manner, this step could result in many complications and annoying situations of trying to find the changes made.

As everyone mentioned already yes every part of the design controls is important. But I feel with these control a few comes to mind that mind need closer attention. That is planning and validation. Planning will set the tone for the entirety of the project. With poor planning there is a potential for catastrophic downstream issues later on as the project progresses. Validation is also very important and needs special attention. Validation is where clinical trials are held to determine the efficacy of device in question. Validation is referring more to the user and how they interact with the design specification, so validating the device may even lead to changes in specifications. 

The essential design control is planning. Anything involving the project comes from the foundation of planning. Without that, the design can't branch out into the necessary steps and adjustments that would be made during the project's lifetime. With this design control, you have the opportunity to produce a well-designed product as well as discuss any ethical concerns that may arise. The most annoying is the design history file. Compiling all this paperwork into condensed and concise documentation can get daunting if mistakes are done before or during the process.