Definition and Scope of Medical Devices
Medical devices are products that do not have a pharmacological or immunological effect, but are used for the purpose of improving, diagnosing, treating, or monitoring human health. These devices, which interact directly or indirectly with the human body, play a critical role in diagnostic and treatment processes. Examples include surgical instruments, dental implants, in vitro diagnostic devices, and pacemakers.
It is of great importance that medical devices are safe and effective, and designed and produced in accordance with certain international standards. In the European Union, these products are regulated under the 93/42/EEC Medical Device Directive (MDD). Turkey has also adapted this directive to its own national legislation.
93/42/EEC Medical Device Directive: General Requirements
The 93/42/EEC Directive introduces certain rules and standards to ensure the safety, quality, and performance of medical devices. It guarantees that devices bearing the CE mark meet certain health and safety requirements.
Main Goals:
- Device Safety: Ensuring the safety of the device for users and patients.
- Performance: Ensuring that the device functions as intended.
- Clinical Data: Supporting evidence of safety and efficacy with clinical evaluations.
CE Marking: The CE mark, which ensures the free movement of medical devices in the European Economic Area, indicates that the product complies with health, safety, and environmental standards. To obtain the CE mark, the device must pass rigorous tests and complete conformity assessment procedures.
Medical Device Classification According to Risk Groups
Medical devices are divided into four main classes based on their contact duration with the human body, degree of invasiveness, and potential risk levels. This classification is based on the rules established within the scope of the 93/42/EEC Directive.
Class I (Low Risk Devices)
Characteristics: Devices of simple structure, carrying low risk. Designed for transient or short-term use.
Examples: Blood pressure monitors, wheelchairs, non-sterile gloves.
Conformity Assessment: Manufacturer’s self-declaration is sufficient. However, for devices with sterile or measuring functions, Notified Body approval may be required.
Rules: Rule 1: Non-invasive, simple devices fall into this class. Rule 2: Devices performing only mechanical functions are also evaluated in this class. Rule 3: Low-risk devices transferring fluids or drugs to the body.
Class IIa (Medium Risk Devices)
Characteristics: Short-term invasive devices and active devices are included in this class. Covers devices in contact with the human body for longer periods.
Examples: Ultrasound devices, dental filling materials, surgical hand tools.
Audit: Must be audited by a notified body.
Rules: Rule 4: Short-term invasive devices (used for less than 30 days) are in this group. Rule 5: Devices used on sensitive organs such as eyes or ears are also in this class.
Class IIb (High Risk Devices)
Characteristics: Long-term invasive devices or devices supporting critical body functions fall into this class.
Examples: Ventilators, dialysis machines, infusion pumps.
Approval Requirements: Requires comprehensive clinical tests and Notified Body audit.
Rules: Rule 6: Devices in contact with body tissues for more than 30 days. Rule 7: Devices in direct contact with blood, tissue, or organs are included in this group.
Class III (Highest Risk Devices)
Characteristics: Devices with the highest risk level. Devices permanently placed in the body or supporting the functions of vital organs fall into this group.
Examples: Pacemakers, artificial heart valves, brain stimulation devices.
Assessment: Clinical studies, independent laboratory tests, and Notified Body approvals are required.
Rules: Rule 9: Permanently implanted devices. Rule 10: Devices directly affecting blood circulation or vital organs.
Special Medical Device Groups
1. Active Implantable Medical Devices (AIMD)
Definition: Devices placed in the human body by surgical intervention and working by receiving energy from outside.
Examples: Pacemakers, nerve stimulation devices.
Safety Requirements: Biocompatibility, long-term safety, and reliability of the energy source must be evaluated.
2. In Vitro Diagnostic Medical Devices (IVD)
Definition: Devices used to perform analysis on samples taken from the human body.
Examples: Blood glucose measuring devices, PCR test kits.
Requirements: Accuracy, sensitivity, and performance tests must comply with ISO 13485. Clinical validity must be ensured.
3. Non-In Vitro Medical Devices
Definition: Devices used outside the body or without direct contact.
Examples: Medical imaging devices.
Technical Requirements: Calibration and measurement sensitivity of the device must be ensured, and instructions for use must be clear.
Risk Analysis: ISO 14971 Standard
The ISO 14971 standard is an internationally recognized standard for risk management of medical devices. All medical device manufacturers use this standard to identify potential hazards, evaluate risks, control risks, and continuously monitor them.
Risk Management Process:
- Risk Management Plan: Defines the procedures to be applied throughout the entire life cycle of the device.
- Hazard Identification: Determination of physical, chemical, biological, or mechanical hazards.
- Risk Analysis: Evaluation of potential effects and probabilities of each hazard.
- Risk Control: Implementation and documentation of measures taken to reduce risks.
- Residual Risk Assessment: Examination of whether the risks remaining after risk control are acceptable.
- Risk/Benefit Analysis: Assessment of whether the benefits provided by the device outweigh the risks.
- Continuous Surveillance: Monitoring the device even after it is put on the market and intervening in case of detection of new risks.
Conformity Assessment Procedures and Technical File
The conformity assessment procedure for the device varies depending on the class of the device. The main procedures are:
EC Type Examination
An independent Notified Body examines the design and technical documents of the device.
Obligation: Especially necessary for Class IIb and III devices.
Full Quality Assurance System
Production processes are continuously audited by a Notified Body. The quality management system must be documented.
Technical File
Must contain all documents proving the performance, safety, and efficacy of the device.
Content: Risk analyses, production processes, quality control methods, clinical data, sterilization procedures, labeling, and instructions for use.
Safety and Performance Requirements
- Biocompatibility Tests: The device must be biocompatible in accordance with the TS EN ISO 10993 standard.
- Sterilization: Sterilization processes of devices must be documented to ensure safety.
- Clinical Evaluation: The efficacy of the device must be supported by clinical data.
Market Surveillance and Conformity Audit
Competent authorities conduct continuous surveillance to ensure the safety of devices put on the market. When any adverse event is detected, corrective measures are recommended to the manufacturer or the device may be recalled.
- Market Surveillance Plan: A comprehensive monitoring plan must be prepared to minimize risks.
- Reporting: Adverse events must be reported to the competent authorities.
Declaration of Conformity
The manufacturer declares that the device complies with the 93/42/EEC Directive and relevant standards. This declaration enables the device to receive the CE mark.
Content:
- Manufacturer Information: Name, address of the manufacturer.
- Device Description: Model, serial number, intended use of the device.
- Compliance with Standards: Specification of applicable ISO standards (e.g., ISO 13485, ISO 14971).
- Authorized Signature: Must be signed by the authorized representative of the manufacturer.
Standards and Regulations
- MDR (Medical Device Regulation): New regulation aiming to increase the safety of medical devices by replacing the 93/42/EEC Directive.
Changes: Stricter clinical evaluation and certification procedures. - ISO 13485: International standard for quality management systems for medical devices.
Requirements: Continuous improvement of production processes and documentation. - ISO 10993: Standard for biocompatibility testing of medical devices.
Tests: Cytotoxicity, hemocompatibility, irritation, and sensitivity tests. - EN ISO 15223-1: Labeling and information requirements for medical devices.
Icon Use: Internationally valid symbols must be used on labels.