Regulatory Compliance in Product & Process Development Phase

Introduction to Medical Device Design Control

• Definition of Design Controls: Design controls represent an interrelated set of practices and procedures incorporated into the design and development process. They function as a system of checks and balances.
• Regulatory Requirements:     * Manufacturer Mandate: Both the FDA and ISO 13485 require medical device manufacturers to establish and maintain procedures to control the design of the product.     * USA (FDA): Regulated under QSR Section 820.30, titled "Design Controls."     * European Union (ISO 13485): Regulated under Section 7.3, titled "Design and development."
• Relationship and Integration:     * Design controls are a component of the Quality System, specifically involving design verification and design validation.     * ISO 13485 Section 7.3 structure includes Planning (7.3.1), Inputs (7.3.2), Outputs (7.3.3), Review (7.3.4), Verification (7.3.5), Validation (7.3.6), and Changes (7.3.7), all involving Resource/Authorization.

Motivation for Design Controls

• Recalls and Safety: Statistics indicate that $44\%$ of recalls are attributed to faulty design.
• Industry Examples:     * Example 1: Medtronic, Inc.: Recalled the Sprint Fidelis family of defibrillation leads due to potential lead fractures.         * Context: Defibrillators are surgically implanted to monitor heart rhythms and deliver electrical shocks or rapid pacing to restore normal rhythm during life-threatening irregular heartbeats.         * Scope: Approximately $268,000$ leads were implanted worldwide, with $172,000$ in the United States.         * Risk: Fractures could lead to unnecessary shocks or total device failure, resulting in reported deaths and serious injuries.     * Example 2: St. Jude Silzone Heart Valves: Recalled in January 2000 due to propensities for leaking.         * Scope: Approximately $36,000$ valves implanted worldwide ($10,500$ in the US).         * Impact: Leaks reduced heart pumping efficiency, leading to heart failure, blood clots, and strokes.         * Root Cause: The use of unsuitable material for the Silzone-coated sewing cuff fabric.
• Top 5 FDA-Quoted Design Deficiencies:     1. Inadequate design and development plan.     2. Inadequate design history file (DHF).     3. Lack of a design control system.     4. Inadequate procedure for design change.     5. Failure to verify or validate design changes.
• Business Motivation: Design control addresses business needs such as understanding customer requirements (Input), creating meaningful specifications (Output/Transfer/Verification/Validation), and ensuring consistent, reliable measurements and processes (Process validation/Control).

Regulatory Compliance and Quality Systems

• Integration with Quality System: During development, the design team must plan, document, and execute activities to show compliance with regulations and customer needs. Outputs must be "embedded" within the firm’s quality system, complementing quality assurance by ensuring intended use and reliability.
• FDA Scope of Requirements:     * PMA Requirement: Design control procedures and a Design History File (DHF) are mandatory for Premarket Approval (PMA).     * Device Classes: All Class II and Class III devices must be developed under design control.     * Class I Exceptions: Specific Class I devices requiring design control include:         * Automated devices (computer software).         * Section 868.6810: Catheter, Tracheobronchial, Suction.         * Section 878.4460: Glove, Surgeon’s.         * Section 880.6760: Restraint, Protective.         * Section 892.5650: System, Applicator, Radionuclide, Manual.         * Section 892.5740: Source, Radionuclide, Teletherapy.
• List of Design Control Activities:     * Design and development planning.     * Design input.     * Product design and analysis.     * Design output.     * Design review.     * Design verification.     * Design validation.     * Design transfer.     * Maintenance of the Design History File (DHF), including design changes.

Design and Development Planning

• General Requirements: Design and development must be planned and controlled, with the results of this planning systematically documented.
• Mandatory Plan Components:     * Project goals and objectives.     * Identification of a complete team and an independent reviewer.     * Assigned responsibilities for each activity and specific due dates.     * Definition of interfaces between different groups.     * Identification of the project's critical path.     * Goals for manufacturability.     * Plans for risk management (per ISO 14971) and other quality system requirements (biocompatibility, validation, accelerated ageing, etc.).     * Defined stages for review and approval.
• Planning Techniques:     1. Action List: Suitable for simple projects; lists tasks, priority, dates, and responsible persons, but does not show task dependencies or sequence.     2. PERT (Program Evaluation Review Technique): Uses boxes for each task to indicate activity sequence and dependencies.     3. Gantt Chart: Uses cascading formulas to calculate start and stop times, providing a visual representation of tasks and milestones.
• Benefits of Planning: Provides a disciplined management approach, specific details for the project, a common communication mechanism, proactive issue resolution, and overall compliance traceability.

Design Input

• Definition: The physical and performance requirements of a device used as the basis for device design. It serves as the foundation for developmental activity and typically consumes $\approx 30\%$ of total project time.
• Requirements:     * Establish procedures to address intended use, including patient and user needs.     * Address requirements that are incomplete, ambiguous, or conflicting.     * Incorporate outputs from risk management.     * Must be reviewed and approved, with documentation including date and signature of the individual(s) approving the requirements.
• Two Core Requirement Types:     1. User Requirements: Derived from the intended user (e.g., patient, surgeon, or technician) in "user language."     2. Product Design Requirements: Translated into "engineering terms" and often developed in conjunction with vendors or suppliers.

Categories of Product Design Requirements

• Functional Requirements:     * Intended use and contraindications.     * Clinical procedures.     * Relevant use settings (where the product will be used).     * Specific users.
• Performance Requirements:     * Characteristics: Physical (ergonomics), chemical, biological, environmental, magnetic, electrical, energy (leakage), and reliability.     * Sterilization and Packaging.     * Market Requirements: Intended geographical market, market segments, labeling requirements, and specific claims.     * Regulatory/QA: Relevant regulatory requirements, industry standards, and test methods.
• Interface Requirements:     * Critical compatibility with external systems.     * User and/or patient interfaces.

Design Input Example: Heel Stick (Babylance)

• Market Segmenting/Sizing:     * Full-Term Size (Mango Orange): For babies weighing more than $1,800-2,000\,grams$ ($4-5\,lbs$).     * Preemie Size (Lime Green): For babies weighing less than $1,800-2,000\,grams$ ($4-5\,lbs$).
• Requirement Analysis:     * Functional: Must cut skin (heel) to bleed blood for collection; must be one-hand operated; must be lightweight.     * Performance: Weight must be < 100\,g; specific height/width/length dimensions; cut depth of $3\,mm$; specific blade thickness and sharpness.     * Interface: Must include a release button and a safety lock.

Reviewing Adequacy of Design Input

• Verification: Each requirement must be verifiable through an objective method of analysis, testing, or inspection.
• Precision: Quantitative limits must be expressed with a measurement tolerance.
• Context: The intended environment of use must be properly characterized.
• Standards: Citations of industry standards must be reviewed for relevance and completeness.
• Consistency: Requirements must be reviewed to ensure there are no conflicting criteria.