For a transcatheter heart valve and delivery system that has already been clinically tested and marketed domestically, if improvements are made only to the delivery system without other changes, which clinical pathway should be chosen for submission?
The applicant should specifically analyze whether the changes to the delivery system affect the product's performance and clinical safety. It is also crucial to focus on whether preclinical study data are sufficient to support that the differences do not impact the product's safety and effectiveness. If the analysis and evaluation are acceptable, and if non-clinical data and clinical data from similar products with the same improvements abroad can support this, the applicant may choose the same product type pathway for clinical evaluation.
Can passive accessories used for supporting and immobilizing patients be declared together with the equipment?
Passive accessories for imaging equipment like CT and MRI, such as supports, pads, cradles, straps, frames, and boards, which are used to fix and support the patient's position during imaging, can be declared together with the imaging equipment.
What performance studies are needed for ceramic materials used in dental restorations?
Ceramic materials for dental restorations require consideration of chemical properties, basic properties, physical and mechanical properties, sintering-related properties, and machining performance studies. Chemical properties include chemical composition and percentage content, type, radioactivity, and chemical solubility. Basic properties cover appearance, uniformity, dimensions, and density. Physical and mechanical properties include glass transition temperature, coefficient of thermal expansion, flexural strength, Weibull modulus, hardness, and fracture toughness. Sintering-related properties involve pre- and post-sintering density and shrinkage. Machining performance includes edge stability and edge precision.
What performance studies are required for citric acid disinfectant solutions?
Performance studies for citric acid disinfectant solutions used for heat disinfection of internal pipelines in hemodialysis machines should at least include: appearance, pH value, fill volume, main active ingredients (e.g., citric acid content), shelf life, metal corrosivity, and microbial kill indicators. If the main active ingredients contain special substances or functions not found in other similar marketed products, the corresponding substance composition, content, and usage performance should be specified.
How should the rated burst pressure indicator be set in the product technical requirements for balloon dilatation catheters?
The rated burst pressure indicator for balloon dilatation catheters should be established in the product technical requirements according to the standards outlined in YY 0285.4-2017 "Intravascular Catheters - Sterile and Single-Use Catheters - Part 4: Balloon Dilatation Catheters." The requirement states that "the pressure at which the balloon bursts should not be less than the nominal rated burst pressure." Since the mode of balloon failure affects the safety of the product, performance study data must also investigate both the rated burst pressure and the failure mode. It is essential to observe and assess the balloon's failure mode, which should ideally be an axial failure mode. If other failure modes occur, a thorough evaluation of their impact on product safety should be conducted. This approach ensures that the balloon dilatation catheters operate safely under the expected conditions of use and that any potential failure modes are well understood and mitigated.
In non-clinical studies of orthopedic implant medical devices, if the declared product is proven equivalent to an already marketed product through equivalence testing, is it necessary to select the worst-case scenario sample for performance studies?
Applicants should conduct research on the declared product, taking into consideration factors such as key dimensions and structural design that may affect product performance, and it is necessary to select samples representing the worst-case scenario for performance studies. For different performance studies, the model specifications chosen for the worst-case scenario might vary. It is recommended to consider the selection of the worst-case scenario for the declared product in conjunction with the performance test methods. Even if the declared product and the already marketed product have the same scope of application, indications, and intended use (for example, if there is a previous generation product and the declared product only differs in product structure composition), the principles mentioned should still be applied even after proving equivalence through equivalence testing. This approach ensures that the product's performance under the most challenging conditions is understood and meets the necessary safety and efficacy standards.
What issues should be focused on in the registration documentation for the measurement function in medical device software?
The "Guidelines for the Review of Medical Device Software Registration (2022 Revised Edition)" specifies that measurement functions (also known as quantification or quantitative functions) can be divided into graphical measurement functions and objective physical measurement functions. The former indirectly reflects the measurement results of objective entities based on graphics, while the latter directly reflects the measurement results of objective entities. Regardless of the type of measurement function, factors such as measurement error and uncertainty must be considered, and measurement accuracy indicators such as linearity, precision, repeatability, reproducibility, range limits, and display error must be clearly defined. Applicants for registration must provide research data on measurement accuracy and inform users about it in the instructions for use. Additionally, objective physical measurements must specify accuracy indicators in the product technical requirements, and graphical measurements must provide warnings about measurement accuracy in the instructions for use. These details are crucial to ensure that the software functions correctly and reliably, and that users are fully informed about the potential limitations and accuracy of the measurements provided by the software.
Can a single-arm target value design be chosen for clinical trials of intracranial drug-coated balloon dilatation catheters?
The essence of a single-arm target value design is to compare the results of the primary evaluation indicators with existing clinical data to assess the effectiveness/safety of the trial device. Compared to parallel controlled trials, single-arm trials inherently suffer from asynchronous control biases, which may lead to selection bias, confounding bias, measurement bias, and evaluation bias. Since no control group is set up, clinical trials using a single-arm target value design cannot confirm the superiority, equivalence, or non-inferiority of the trial device but can only verify that the effectiveness/safety of the trial device meets the recognized minimum standards in the field. A single-arm target value design may be considered when the device technology is mature and there is a deep understanding of the applicable diseases, or when setting up a control is objectively unfeasible (for example, if the risk-benefit ratio of the trial device compared to existing treatments is too disparate making a control ethically unfeasible; or if existing treatments are not feasible due to objective conditions). Given the technical development and current clinical application of intracranial drug-coated balloon dilatation catheters, they do not meet the basic principles for a single-arm target value design. It is recommended to choose a randomized controlled trial (RCT) design for clinical trials.
What aspects should be considered in the structural design of implant products as described in the product overview?
The device characteristics related to the structural design of implant products should include: 1) Implant shape design; 2) Macro design parameters of threads such as single-thread, double-thread, triple-thread, and geometric parameters of thread units (thread shapes like V-shaped, rectangular, serrated, biased trapezoidal, reverse biased trapezoidal, square, etc.), thread pitch, and thread depth; 3) Features of the implant neck (such as bone level, soft tissue level); 4) Design of the implant apex contour (such as blunt, sharp, cylindrical, conical) and the apex thread apex angle (such as symmetrical, top flat bottom inclined, top inclined bottom flat); 5) Implant-abutment connection types (such as internal hex connection, external octagon connection, Morse taper connection); 6) Axial plane characteristics of the implant (such as axial anti-rotation grooves); 7) Platform switching design (if applicable).
Under what circumstances can surgical instrument products be exempt from biological testing?
Based on the current level of understanding, surgical instrument products that are made entirely of metal materials and have been validated to meet the national, industry, and international standards for metallic materials used in surgical implants or surgical instruments, as well as the material grades specified in relevant national and industry standards (such as the material grade specified in YY/T 0176 "General Technical Conditions for Medical Scissors"), can be exempt from biological testing. This exemption is possible provided that documentation validating the chemical composition of the materials is provided (if it can be demonstrated that the manufacturing process does not affect the chemical composition of the materials, submission in the form of a raw material specification sheet may be acceptable).