(74 days)
Intended Use: MAYFIELD® Radiolucent Skull Pins are used with a skull clamp that is placed on the patient's skull to hold their head and neck in a particular position during surqical procedures when rigid skeletal fixation is desired and Intra-Operative CT or MRI imaging is used.
Indications for Use: The MAYFIELD® Radiolucent Skull Pins are indicated for use in open and percutaneous craniotomies and spinal surgeries when rigid skeletal fixation is necessary and when Intra-Operative CT or MRI imaging of the patient is used.
The MAYFIELD Radiolucent Skull Pin 4-0-A-2020 [radiolucent pin] consists of the following components: a molded black-color ABS plastic base, and a machined sapphire-crystal pin point. The radiolucent pins are packaged three (3) pins per pouch, two (2) pouches per carton and EO sterilized. The radiolucent pins are single-use devices used to rigidly fix the patient's head and/or spine during surgery. The radiolucent pins are assembled from two components; a molded ABS plastic base [the same as used in the predicate device, MAYFIELD Disposable Skull Pins 4-0-A-1072][A1072 pins] and a pin point made of sapphire crystal that is machined to the same dimensions as the A1072 pin point. In preparation for surgery three (3) radiolucent pins are installed in a MAYFIELD Radiolucent Skull Clamp; two radiolucent pins in the Rocker Arm side and a single radiolucent pin on the opposite side. The radiolucent pins are EO sterilized, just as the A1072 pins mentioned above, and are ready for use right from the sterile pouch.
The provided document describes the acceptance criteria and a study comparing the MAYFIELD® Radiolucent Skull Pins (4-0-A-2020) to a predicate device, the MAYFIELD Disposable Skull Pins (4-0-A-1072, K923789).
Here's a breakdown of the requested information:
1. Acceptance Criteria and Reported Device Performance
The acceptance criteria for the new device were based on demonstrating substantial equivalence to the predicate device in terms of performance, with an additional benefit in CT/MRI compatibility.
| Acceptance Criteria Category | Specific Criteria | Reported Device Performance (MAYFIELD® Radiolucent Skull Pins) |
|---|---|---|
| Mechanical Performance | Penetration Testing (Axial Load): Repeated penetrations with no degradation of the pin point. | Results of comparisons of Penetration Testing with Axial Loading demonstrate that the radiolucent pins perform substantially the same as the predicate device. Multiple tests showed no device failures and performance equal to the predicate device. |
| Penetration Testing (Axial & Shear Load): Sustained side forces exceeding a safety factor of 2. | Results of comparisons of Penetration Testing with Axial Loading and Shear Loading demonstrate that the radiolucent pins perform substantially the same as the predicate device. Multiple tests showed no device failures and performance equal to the predicate device. | |
| Imaging Compatibility | CT/MRI Artifact Reduction: Significantly less artifact compared to the predicate device when used with intra-operative CT or MRI imaging. | Results of comparisons of CT Images of a melon held by radiolucent pins and a melon held by stainless steel pins [predicate device] show significantly less artifact resulting with the radiolucent pins than with the stainless steel [predicate device] pins. This demonstrates superiority in this specific aspect. |
| Material Equivalence | Base Material: Same as predicate device (ABS plastic). | The radiolucent pins utilize the same molded base made of the same ABS plastic material as the predicate device. |
| Manufacturing Process | Machining and Molding: Pin point machined to same dimensions as predicate; base molded to same dimensions as predicate. | The pin point is machined to the dimensions listed on the radiolucent pin point drawing, which lists the same dimensions as the stainless steel pin point drawing. The pin base is the same as the pin base used for the predicate device and is molded to the dimensions listed on the pin base drawing. |
| Sterilization | Method and SAL: Sterilized using a validated Ethylene Oxide sterilization cycle based on ANSI/AAMI/ISO 11135-1994, with a Sterility Assurance Level (SAL) of 10⁻⁶. Packaging suitable for sterile surgical devices. | The radiolucent pins are supplied sterile and are cleaned, assembled, packaged, and sterilized in exactly the same manner as the predicate device, using a validated Ethylene Oxide sterilization cycle (ANSI/AAMI/ISO 11135-1994) with an SAL of 10⁻⁶. Packaging is industry standard medical-grade, same as the predicate. |
| Intended Use / Indications | Substantially equivalent to the predicate device, with the additional mention of intra-operative CT or MRI imaging. | The intended uses and indications for use are identical to the predicate device, with the specific exception that the radiolucent pins are indicated for use when Intra-Operative CT or MRI imaging is used. |
| Method of Use | Three pins installed in receptacles of a MAYFIELD Skull Clamp. | Three (3) pins are installed in receptacles of a MAYFIELD Radiolucent Skull Clamp 4-0-A-2002 (or MAYFIELD 2000 Skull Clamp 4-0-A-2000 for the predicate), which is consistent with the method of use for the predicate device. |
2. Sample size used for the test set and the data provenance
- Sample Size: The document does not specify a precise numerical sample size for the "test set" in terms of how many pins were tested for mechanical performance. It states "Multiple Penetration Tests" were run. For the CT imaging comparison, it mentions "CT Images of a melon held by radiolucent pins and a melon held by stainless steel pins." This suggests at least one comparison image set, but not a large, statistically robust sample.
- Data Provenance: The nature of the tests (mechanical and imaging on a melon) suggests these were lab-based, engineering tests rather than clinical data. Therefore, there's no mention of country of origin of data or whether it was retrospective or prospective. It is entirely prospective in the sense that the tests were conducted specifically for this submission.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
Not applicable. The "ground truth" for these tests was objective, quantifiable measurements of mechanical integrity and image artifact, not expert interpretation. For example, "no degradation of point" or "sustained side forces exceeding safety factor" are engineering standards, and "significantly less artifact" would be based on image analysis, not expert consensus on pathology.
4. Adjudication method for the test set
Not applicable. The tests performed are objective engineering and imaging comparisons, not involving human interpretation that would require adjudication.
5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
Not applicable. The tests described are for a medical device (skull pins), not an AI algorithm. Therefore, no MRMC study or assessment of human reader improvement with AI assistance was conducted or mentioned.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
Not applicable. This is not an AI algorithm. The performance evaluation is for the physical device.
7. The type of ground truth used
The ground truth used was based on objective engineering measurements and imaging data analysis.
- For mechanical performance (Penetration Tests): The ground truth was defined by physical parameters such as "no degradation of point" and "sustained side forces exceeding safety factor of 2," which are quantifiable engineering metrics.
- For imaging compatibility: The ground truth was based on the direct comparison of image artifacts in CT scans, visually and potentially quantitatively assessed as "significantly less artifact."
8. The sample size for the training set
Not applicable. This is a medical device, not a machine learning model, so there is no concept of a "training set."
9. How the ground truth for the training set was established
Not applicable, as there is no training set for this device.
§ 882.4460 Neurosurgical head holder (skull clamp).
(a)
Identification. A neurosurgical head holder (skull clamp) is a device used to clamp the patient's skull to hold head and neck in a particular position during surgical procedures.(b)
Classification. Class II (performance standards).