Archive for the ‘Design Validation’ Category

How do you audit design controls using the process approach?

In Change Control, Design & Development, Design Inputs, Design Outputs, Design Validation, Design Verification, Forward to MDA, Internal Auditing, IOVV, ISO 13485, ISO 14971, Risk Management on June 23, 2012 at 4:44 am

A new connection I made on LinkedIn joined the RA Review Group, and they suggested that anything related to the topic of Design and Development would be of interest for a blog topic. Therefore, I thought I would share a secret with everyone reading my blog…

This blog has been moved to the following location and the name has been changed: http://bit.ly/AuditDesign.

This blog website and the blogs within it are gradually being transferred over to my new website: http://www.MedicalDeviceAcademy.com. The titles may change, and there may be minor revisions to the content as the blogs are reviewed and edited. There will be a subscription list created for the new blog site. If you would like to be added to the list for the new blog site, please email me directly at: rob@13485cert.com.

I have left the links to the videos I love.

Entertainment for this week is Diana Krall‘s recording of Bésame Mucho. I have also included another recording by Andrea Bocelli with English and Spanish subtitles for anyone that wondered what the words meant. The song loses a little of it’s appeal in translation, but English is not one of the Romance Languages.

The Ultimate Design Control SOP

In Design & Development, Design Inputs, Design Outputs, Design Validation, Design Verification, Elsmar Cove, ISO 13485, Medical Device, Procedures, US FDA on May 27, 2012 at 12:33 am

Disclaimer: There is no need to create the Ultimate Design Control SOP. We need medical devices that are safer and more effective.

If Adele is worthy of six Grammy Awards, she’s probably worthy of a blog link too. Rumor has it that this is my personal favorite from Adele.

In my previous blog posting, I indicated six things that medical device companies can do to improve design controls. While the last posting focused on better design team leaders (WANTED: Design Team Needs Über-Leader), this posting focuses on writing stronger procedures. I shared some of my thoughts on writing design control procedures just a few weeks ago, but my polls and LinkedIn Group discussions generated great feedback regarding design control procedures.

One of the people that responded to my poll commented that there was no option in the poll for “zero”. Design controls do not typically apply to contract manufacturers. These companies make what other companies design. Therefore, their Quality Manual will indicate that Clause 7.3 of the ISO 13485 Standard is excluded. If this describes your company, sit back and enjoy the music.

Another popular vote was “one”. If you only have one procedure for design controls, this meets the requirements. It might even be quite effective.

When I followed up to poll respondents asking how many pages their procedures were, a few people suggested “one page”. These people are subscribing to the concept of using flow charts instead of text to define the design control process. In fact, I use the following diagram to describe the design process all the time: The Waterfall Diagram!

From the US FDA Website.

I first saw this in the first AAMI course I took on Design Controls. This is on the FDA website somewhere too. To make this diagram effective as a procedure, we might need to include some references, such as: work instructions, forms, the US FDA guidance document for Design Controls, and Clause 7.3 of the ISO Standard.

The bulk of the remaining respondents indicated that their company has eight or more procedures related to design controls. If each of these procedures is short and specific to a single step in the Waterfall Diagram, this type of documentation structure works well. Unfortunately, many of these procedures are a bit longer.

If your company designs software, active implantable devices, or a variety of device types—it may be necessary to have more than one procedure just to address these more complex design challenges. If your company has eight lengthy procedures to design Class 1 devices that are all in the same device family, then the design process could lose some fat.

In a perfect world everyone on the design team would be well-trained and experienced. Unfortunately, we all have to learn somehow. Therefore, to improve the effectiveness of the team we create design procedures for the team to follow. As an auditor and consultant I have reviewed 100+ design control processes. One observation is that longer procedures are not followed consistently. Therefore, keep it short. Another observed I have made is that well-design forms help teams with compliance.

Therefore, if you want to rewrite your design control SOP try the following steps:

  1. Use a flow chart or diagram to illustrate the overall process
  2. Keep work instructions and procedures short
  3. Spend more time revising and updating forms instead of procedures
  4. Train the entire team on design controls and risk management
  5. Monitor and measure team effectiveness and implement correct actions when needed

The following is a link to the guidance document on design controls from the US FDA website.

Refer to my LinkedIn polls and discussions for more ideas about design control procedures:

  1. Medical Devices Group
  2. Elsmar Cove Quality Forum Members Group

In addition to the comments I made in this blog, please refer back to my earlier blog on how to write a procedure.

What is the Design Input?

In 510(k), CE Mark, CE Medical, Class IIb, Class III, Design & Development, Design Inputs, Design Outputs, Design Validation, Design Verification, ISO 13485, Medical CE, Medical Device, Risk Management on May 12, 2012 at 7:09 pm

Micky, this is for you.

I have been directly involved in dozens of design projects throughout my career, and during the past three years I have audited 50+ Design Dossiers for CE Marking of Medical Devices. Throughout most of these design projects, I have noticed one common thread—a misunderstanding of design inputs.

ISO 13485 identifies the requirements for Design Inputs. These requirements are:

  1. Functional (7.3.2a)
  2. Performance (7.3.2a)
  3. Safety (7.3.2a)
  4. Statutory / Regulatory (7.3.2b)
  5. Previous and Similar Designs (7.3.2c)
  6. Essential Requirements (7.3.2d)
  7. Outputs of Risk Management (7.3.2e)
  8. Customer Requirements (7.2.1)
  9. Organizational Requirements (7.2.1)

The most common error seems to be the failure to include the outputs of risk management. For those of you that have used design FMEA’s—that’s what the right-hand columns are for. When you identify suggested actions to mitigate risks with the current design, these actions should be translated into inputs for the “new and improved” model.

The second most common error seems to be failure to consider regulatory requirements. There are actually two ways this mistake is frequently made: 1) Canadian MDR’s were not considered as design inputs for a device intended for Canadian medical device licensing, and 2) an applicable ISO Standard was not considered (i.e. – “State of the Art” is Essential Requirement 2 of the Medical Device Directive or MDD).

The third most common error, and the one that drives me crazy, is confusion of design outputs and design inputs. For example: an outer diameter of 2.3 +/- 0.05 mm is not a design input for a 7 French arterial catheter. This is a design output. The user need might be that the catheter must be small enough to fit inside the femoral artery and allow interventional radiologists to navigate to a specific location to administer therapy. Validation that the new design can do this is relatively straight forward to evaluate in a pre-clinical animal model or a clinical study. The question is, “What is the design input?”
Design inputs are supposed to be objective criteria for verification that the design outputs are adequate. One example of a design input is that the catheter outer diameter must be no larger than a previous design that is an 8 French catheter. Another possible design input is that the catheter outer diameter must be less than a competitor product. In both examples, a simple measurement of the OD is all that is required to complete the verification. This also gives a design team much more freedom to develop novel products than a narrow specification of 23 +/- 0.05 mm allows for.

If you are developing a Class II medical device for a 510(k) submission to the FDA, special controls guidance documents will include design inputs. If you are developing a Class IIa, Class IIb or Class III medical device for CE marking, there is probably an ISO Standard that lists functional, performance and safety requirements for the device. Regulatory guidance documents and ISO Standards usually reference test methods and indicate acceptance criteria. When you have a test method and acceptance criteria defined, it is easier to write a verification protocol. Therefore, design teams should always strive to document design inputs that reference a test method and acceptance criteria. If this is not done, verification protocols are much more difficult to write.

In my earlier example, the outer diameter of 2.3 +/- 0.05 mm is a specification. Unfortunately, many companies would document this as an input and use the final drawing as the output. By making this mistake, “verification” is simply to measure the outer diameter to verify that it matches the drawing. This adds no value and if the specifications are incorrect the design team will not know about it.

A true verification would include a protocol that identifies the “worst-case scenario” and verifies that this still meets the design input requirements. Therefore, if the drawing indicates a dimensional tolerance of 2.3 +/- 0.05, “worst-case” is 2.35 mm. The verification process is to measure either a previous version of the product or a competitor’s catheter. The smallest previous version or competitor catheter tested must be larger than the upper limit of the design output for outer diameter of the new catheter.

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