(197 days)
The RadiaDyne Prostate Immobilizer Rectal Balloon is a single-use disposable, inflatable, non-powered positioning device intended for use in the temporary positioning of the rectal wall and adjacent structure in the male human anatomies. The purpose of the device is to stabilize the prostate during Computed Tomography (CT) exam and X-ray, when these imaging techniques are used for Radiation Therapy (RT) planning. The placement of the balloon requires a Physician or a Physician directed healthcare professional, and is performed as a separate procedure apart from the standard CT exam and RT treatment.
The RadiaDyne Prostate Immobilizer Rectal Balloon is designed as an immobilizer to assist in positioning the prostate in a more predictable and reproducible location during Computed Tomography (CT) exam and X-ray, when these imaging techniques are used for Radiation Therapy (RT) planning. The Prostate Immobilizer Rectal Balloon is inserted into the rectum and inflated prior to the start of a CT scan or RT therapy procedure. The device stabilizes the prostate once the device is inflated. The Prostate Immobilizer Rectal Balloon is deflated and removed after each individual scan or therapy procedure is complete, and a new balloon is used in the next therapy session. RadiaDyne's device is designed for single use, is provided non-sterile to the end user, is not intended to be sterilized by the end user, and is packaged in a kit configuration. Each kit contains the following items: Rectal Balloon (polyurethane); Syringe (accessory to the device); Lubricant (accessory to the device); Locking Stopper (accessory to the device); and Instructions Manual. The main section of the device consists of a balloon and tubing which are made of polyurethane. The remainder of the device is made from other medical grade materials. The device can be inflated with either air or water, and this process is carried out with the single use disposable syringe that is supplied with the device in the accessory kit. The locking stopper supplied with the Prostate Immobilizer Rectal Balloon controls the depth at which the balloon is inserted into the rectum. The device can therefore be locked into place once inserted into place. RadiaDyne's Prostate Immobilizer Rectal Balloon is offered with a gas release valve (Models GRB) and without a gas release valve (Models: RB). Prior to insertion of the balloon, rectal gas can be removed from the rectum by methods not involving the balloon, such as inserting a pediatric catheter. The gas release model incorporates an open conduit through the balloon stem so that the rectal gas can be released once the balloon is inserted. After inflation, the gas release conduit continues to provide an escape path for any additional gas arriving at the superior end of the balloon, thus preventing gas accumulation during the procedure. The gas release valve is always open and does not require any action to function. If the model without the gas release valve is used, some transient gas may accumulate during the procedure, as is customary when no balloon is inserted. Aside from this feature, the GRB and RB models are identical in materials, construction and function.
This document describes the acceptance criteria and supporting studies for the RadiaDyne Prostate Immobilizer Rectal Balloon.
1. Acceptance Criteria and Reported Device Performance
The acceptance criteria for the RadiaDyne Prostate Immobilizer Rectal Balloon are primarily based on non-clinical performance testing and literature review. The performance data generally indicate that the device meets these criteria.
| Acceptance Criteria Category | Acceptance Criteria | Reported Device Performance and Study |
|---|---|---|
| Biocompatibility/Materials | - Cytotoxicity (no reactivity). | - Cytotoxicity: Test articles had a toxicity grade of 0, indicating no reactivity. |
| - Skin Irritation (no significantly greater biological reaction than control sites, negligible primary irritation index). | - Skin Irritation: Results showed no significantly greater biological reaction than control sites, with a primary irritation index of 0.0 (negligible). | |
| - Sensitization (Grade I reaction, weak allergenic potential). | - Sensitization: Grade I reaction, classified as having weak allergenic potential. | |
| - Acute Systemic Toxicity (no significant difference between test and control animals). | - Acute Systemic Toxicity: No significant difference between test and control animals. | |
| Shelf Life/Sterility | - Device remains within acceptable bioburden limits and functions properly after 2 years of storage. | - Shelf-life testing data supported a 2-year shelf-life, with tested devices well below the specified bioburden limit. The device is not sold as sterile. |
| Performance Testing - Bench | - Bioburden testing (within specified limits). | - Bioburden testing: Performed based on (b)(4) Trade Secret Formula, results indicated acceptable bioburden levels. |
| - Leakage testing (device holds pressure without leaks). | - Leakage Testing: All devices are filled and held under pressure before release, passing the leak test. | |
| - Tensile-strength and Burst-strength (in air) (capable of withstanding a test-fill volume of (b)(4) Trade Secret Formula & Process of H2O before rupturing, specific tensile strength). | - Tensile-strength and Burst-strength (in air): Balloon capable of withstanding (b)(4) Trade Secret Formula & Process of H2O before rupturing. Tensile strength (b)(4) Trade Secret Formula & Process using a standard COUPO11 at (b)(4) Trade Secret Formula & Process of travel. | |
| - Burst-strength testing (in vivo) (capable of inflating to designed volume plus safety factor in simulated in vivo use). | - Burst-strength testing (in vivo): Each product code is designed for a (b)(4) Trade Secret Formula inflation volume and tested to inflate to this volume plus a safety factor in a simulated rectal environment. | |
| - Stopper resistance testing (ensures secure placement and performance). | - Stopper resistance testing: Involves controlled testing of (b)(4) Trade Secret Formula & Process and the combination of (b)(4) Trade Secret Formula & Process. | |
| - Vent testing (if applicable, air flow greater than (b)(4) Trade Secret Formula & Process for gas release models). | - Vent testing: For gas release models, air flow must be greater than (b)(4) Trade Secret Formula & Process, which was conducted by (b)(4) Trade Secret Formula & Process. | |
| Clinical Effectiveness/Safety (Literature Review) | - Reduces prostate movements and intrafraction motion, improves target localization, and reduces rectal wall volume in high dose regions during radiation therapy. |
- Well-tolerated by patients, with acceptable rates of acute anorectal toxicity.
- No serious complications (e.g., perforations or tissue damage) related to balloon application.
- Effectiveness in releasing bowel gas and decreasing balloon displacement for gas-release models.
- Risks mitigated by applying general and special controls. | - Wachter et al. [1]: Observed maximum prostate AP displacements >5 mm in 2/10 patients with balloons vs. 8/10 without, concluding reduced prostate movements. 252 patients treated, no complications related to balloon application.
- D'Amico et al. [2]: Reduced intrafraction motion (maximum prostate AP displacement from 4 mm to ≤1 mm), well tolerated by all patients.
- Woel et al. [3]: Balloon well tolerated by all patients, none discontinued use. Expected increase in acute toxicities resolved by end of treatment or 3 months after.
- Patel et al. [4]: Significantly reduced rectal wall volume in high-dose region, well tolerated without complications (some needed lidocaine).
- Bastasch et al. [5]: 99.2% (393/396) patients tolerated 100 ml barium-enema type endorectal balloon for entire 35-day course. 0.8% required volume reduction, 4.3% lubricant, 11.6% anal med, 6.8% antidiarrhea med. Clinically acceptable acute anorectal toxicity, no Grade 3 or 4.
- Ronson et al. [6]: 97.6% (3474/3561) patients tolerated balloon throughout treatment. Rectal balloons with fill volumes=120cc were well tolerated. Subject balloon fill volume (60-100ml) is less.
- Both et al. [7]: Daily endorectal balloon placement consistently stabilized prostate, preventing clinically significant displacement (>5 mm).
- Wang et al. [8]: Quantified interafraction prostate motion, showing reduced motion in the subject endorectal balloon group, especially in the anterior-posterior direction.
- Wootton et al. [9]: Gas-release mechanism effectively released bowel gas, decreased balloon displacement. |
| Labeling | - Adequate instructions for use on proper insertion, positioning, and inflation. - Appropriate contraindications and warnings.
- Expiration date supported by performance data.
- Statement on sterility (non-sterile). | - Labeling includes detailed instructions, specific warnings, contraindications (e.g., hemorrhoids, recent surgery), and an expiration date (2 years). States non-sterile and for single use. Consistent with clinical data. |
2. Sample Sizes and Data Provenance for Test Set (Clinical Studies)
The document does not detail a single "test set" in the context of a controlled clinical trial for the device's regulatory acceptance. Instead, it relies on a review of published clinical literature (retrospective and prospective studies) that used either similar devices or the subject device. The information below summarizes the sample sizes and provenance from these cited studies.
- Wachter et al. [1]:
- Sample Size: 10 patients (for initial observation of AP displacements); 252 patients treated with fractionated radiation therapy.
- Provenance: Not explicitly stated, but likely from a clinical setting where radiation therapy for prostate cancer is performed. Retrospective observations from a treated cohort.
- D'Amico et al. [2]:
- Sample Size: Not explicitly stated, but implies multiple patients as "all patients" tolerated placement and inflation.
- Provenance: Clinical setting, "repeated CT-imaging with 1 min time intervals" suggests a prospective measurement during a treatment or simulation session.
- Woel et al. [3]:
- Sample Size: Multiple patients, as "patients treated with four-field three-dimensional (3D) conformal radiation therapy (CRT)". "all of the patients" tolerated the balloon. Specific number not given.
- Provenance: Clinical study, evaluating acute toxicity in patients undergoing radiation therapy.
- Patel et al. [4]:
- Sample Size: Not explicitly stated, but refers to "patients," indicating more than one. "None of the patients in this study..."
- Provenance: Clinical study, demonstrating rectal dose sparing.
- Bastasch et al. [5]:
- Sample Size: 396 patients.
- Provenance: Baylor College of Medicine/Methodist Hospital group, study from 1998 onwards. Retrospective analysis of patient tolerance during IMRT.
- Ronson et al. [6]:
- Sample Size: 3561 patients.
- Provenance: Not explicitly stated, but likely a large clinical cohort study.
- Both et al. [7]:
- Sample Size: Not explicitly stated, but focused on "intrafraction prostate displacements measured with electromagnetic tracking system" in a clinical setting using the subject balloon system.
- Provenance: Clinical study, using the subject device.
- Wang et al. [8]:
- Sample Size: Not explicitly stated, comparing "patient groups treated with and without daily endorectal balloons".
- Provenance: Clinical study, using the subject device.
- Wootton et al. [9]:
- Sample Size: Not explicitly stated, but was a "retrospectively examined" study.
- Provenance: Clinical study, using the subject device with a gas-release mechanism.
3. Number of Experts and Qualifications for Ground Truth (Clinical Studies)
The document does not describe a traditional "ground truth" establishment process for a diagnostic device test set involving experts reviewing images. Instead, the "ground truth" for the device's effectiveness and safety is inferred from:
- Clinical Outcomes: Stability of the prostate, reduction in intrafraction motion, reduction in rectal wall volume in high dose regions, patient tolerance, and lack of severe complications (e.g., perforation, tissue damage).
- Clinical Judgement/Observations: The studies cited were conducted by medical professionals in radiation oncology. The "experts" are the physicians and healthcare professionals involved in delivering radiation therapy and assessing patient outcomes. Their qualifications are implicit in the nature of the studies (e.g., oncologists, radiation therapists performing patient care and data collection).
There is no mention of a specific number of independent experts adjudicating ground truth for device performance in the context of AI studies or similar applications.
4. Adjudication Method for Test Set
Not applicable. The regulatory decision hinges on a summation of existing scientific literature and specific bench testing, not a single comparative study with a human-adjudicated test set in the manner of AI/CADe device evaluations (e.g., 2+1 adjudication).
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No MRMC comparative effectiveness study was mentioned regarding human readers improving with AI vs. without AI assistance. This device is a physical medical device, not an AI or imaging interpretation tool. The studies focus on the physical effect of the balloon on prostate motion and patient tolerance during radiation therapy, not on human interpretive performance.
6. Standalone (Algorithm Only) Performance
Not applicable. The device is a physical medical device, not a software algorithm.
7. Type of Ground Truth Used
The ground truth for the device's effectiveness and safety is derived from:
- Clinical Outcomes Data: This includes measurements of prostate displacement (AP displacement, intrafraction and interafraction motion), assessment of rectal toxicity (acute gastrointestinal, genitourinary, dermatological toxicity), patient tolerance, and observed complications (e.g., perforations, tissue damage).
- Quantitative Imaging Analysis: Studies used repeated CT examinations and electromagnetic tracking systems to quantify prostate motion.
- Biocompatibility Standards: Adherence to established standards for material safety (cytotoxicity, irritation, sensitization, acute systemic toxicity).
- Bench Testing Standards: Verification against engineering specifications for leakage, burst strength, tensile strength, and vent performance.
8. Sample Size for Training Set
Not applicable. This is a physical medical device, not an AI/machine learning algorithm, so there is no "training set." The supporting information is based on literature review and physical bench tests.
9. How Ground Truth for Training Set Was Established
Not applicable, as there is no training set for this physical device.
§ 892.5720 Rectal balloon for prostate immobilization.
(a)
Identification. A rectal balloon for prostate immobilization is a single use, inflatable, non-powered positioning device placed in the rectum to immobilize the prostate in patients undergoing radiation therapy. The device is intended to be used during all the phases of radiation therapy, including treatment planning, image verification, and radiotherapy delivery.(b)
Classification. Class II (special controls). The special controls for this device are:(1) The premarket notification submission must include methodology and results of the following non-clinical and clinical performance testing:
(i) Biocompatibility testing of the final finished device;
(ii) If provided sterile, sterilization validation;
(iii) If not provided sterile, bioburden testing of the final finished device;
(iv) Shelf life and expiration date validation; and
(v) Performance testing including but not limited to:
(A) Venting mechanism (if device has a vent mechanism);
(B) Safety mechanism(s) to prevent advancement beyond its intended safe placement; and
(C) Structural integrity testing (
e.g., tensile strength, balloon leakage and burst strength).(2) Labeling that includes:
(i) Appropriate warnings and contraindications, including, but not limited to the following statements:
(A) “Do not transport the patient with the rectal balloon inserted. The balloon should be removed prior to transport.”;
(B) “Failure to perform the standard imaging position verification protocol may cause the device to not perform as intended.”;
(C) “Reduce the rectal balloon fill volume if the patient experiences discomfort due to the rectal balloon inflation.”; and
(D) “Do not apply excessive pressure/force on the shaft or tubing of the rectal balloon.”
(ii) Adequate instructions for use on the proper insertion procedure, positioning, and inflation of the rectal balloon;
(iii) Whether the device is sterile or non-sterile; and
(iv) An expiration date.