(90 days)
The Sparrow Ascent is a transcutaneous nerve field stimulator that is intended to be used in patients experiencing opioid withdrawal in conjunction with standard symptomatic medications and other therapies for opioid withdrawal symptoms under the supervision of trained clinical personnel.
The Sparrow Ascent is a transcutaneous auricular neurostimulation (tAN) system intended to provide non-invasive, transcutaneous stimulation of the nerves on and/or around the auricle (ear). The device is indicated as an aid in the reduction of opioid withdrawal symptoms in adult patients. The Sparrow Ascent is a battery operated, prescription device that delivers mild electrical stimulation to the nerves on and/or around the auricle (ear), which carry information to the central nervous system. The Sparrow Ascent is to be used in clinical environments (e.g., doctor's office, clinics, rehab centers, and hospitals) and/or at home. Users of the subject device include adults experiencing opioid withdrawal symptoms. Stimulation parameters (i.e., the strength of stimulation) are set by the user's clinician, and users can only adjust stimulation intensity at home. The system consists of three main components 1) a disposable Earpiece, 2) a Cable, and 3) the External Pulse Generator (EPG).
Here's a breakdown of the acceptance criteria and the study details for the Sparrow Ascent device, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The FDA clearance letter does not explicitly state pre-defined acceptance criteria in terms of specific performance metrics (like sensitivity, specificity, or % reduction). Instead, the clinical study's primary efficacy endpoint served as the performance criterion for effectiveness.
| Acceptance Criteria (Primary Efficacy Endpoint) | Reported Device Performance |
|---|---|
| Successful mean percent change in COWS score (defined as a ≥15% reduction) from baseline, 60 minutes after the start of active tAN therapy. | Successfully met. At the conclusion of Day 1 (120 minutes), 93.8% of participants had a clinically significant reduction in COWS score (≥15% reduction). This increased to 100% on Day 2 and was sustained across Day 5. |
| Safety Endpoints: Prevalence of all adverse events (AEs), serious adverse events (SAEs), adverse device events (ADEs), serious adverse device effects (SADEs), unanticipated serious adverse device effects (USADEs), and device deficiencies. | In 14 patients, who experienced a total of 943.6 hours of skin contact, there were no instances of adverse tissue reactions reported. The overall clinical study demonstrated acceptable safety profile, though specific AE rates are not detailed in this summary. |
| Biocompatibility: Demonstrated compliance with ISO 10993 standards and supportive information from the RESTORE clinical study. | Compliance with ISO 10993 series for cytotoxicity, skin sensitization, and irritation. RESTORE clinical study further supported biocompatibility with no adverse tissue reactions in 943.6 hours of skin contact among 14 patients. |
| Software Verification: Compliance with IEC 62304 and ISO 14971. | Explicitly states compliance with IEC 62304 and ISO 14971. |
| Electromagnetic Compatibility and Electrical Safety: Compliance with ANSI/AAMI 60601-1, 60601-1-11, and 60601-1-2. | Explicitly states compliance with ANSI/AAMI 60601-1, 60601-1-11, and 60601-1-2. |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size (Clinical Study): 23 participants were enrolled, and 20 received tAN therapy.
- Data Provenance: The study was conducted at two US sites, making the data provenance United States and prospective (as it was a designed clinical study for this purpose).
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
The document does not mention the use of experts to establish a "ground truth" for the test set in the traditional sense of image interpretation or diagnosis. The ground truth for effectiveness was based on the Clinical Opiate Withdrawal Scale (COWS) scores, which are a standardized and objective measure of opioid withdrawal symptoms. These scores are typically assessed by trained clinical personnel. The document does not specify the number or qualifications of the personnel who administered the COWS scores in this study.
4. Adjudication Method for the Test Set
The document does not describe a traditional adjudication method for the test set data (e.g., 2+1, 3+1). The primary and secondary endpoints were based on changes in COWS scores, which are quantitative measures. The study was a double-blind, randomized, controlled study, which inherently helps to reduce bias in the assessment of outcomes.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and Effect Size
No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. The device is a direct treatment device (nerve stimulator), not an AI-powered diagnostic tool for interpretation by human readers. Therefore, the concept of "how much human readers improve with AI vs without AI assistance" is not applicable here.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done
The device itself is a "standalone" therapeutic device (a transcutaneous nerve stimulator) that delivers stimulation. It does not involve an algorithm providing outputs for human interpretation. Its performance is assessed directly on patient outcomes (reduction in COWS scores). The "algorithm" in this context refers to the device's operational parameters, not an AI diagnostic algorithm. The study described assesses the device's direct therapeutic effectiveness.
7. The Type of Ground Truth Used
The ground truth for the effectiveness study was clinical symptom scores (COWS scores), which are a standardized and objective measure of opioid withdrawal severity. Safety ground truth was based on reported adverse events (AEs).
8. The Sample Size for the Training Set
The document refers to the clinical study of the predicate device (K201873) and "leverag[ing] prior clinical testing" for effectiveness, but it primarily details the study performed for the current device (Sparrow Ascent). It's not clear if there was a separate "training set" in the context of machine learning, as this is a medical device, not an AI algorithm. The study described appears to be the primary clinical evidence for the device's effectiveness.
9. How the Ground Truth for the Training Set Was Established
As this is a medical device and not an AI algorithm, the concept of a "training set" and establishing "ground truth for the training set" in the machine learning sense is not directly applicable. The effectiveness was established through a prospective, double-blind, randomized, controlled multi-center clinical study evaluating the impact of the nerve stimulator on COWS scores, as described in section 7 above. The summary also references the prior clearance of the predicate device (NSS-2 Bridge, DEN170018) which would have undergone its own clinical studies to establish similar effectiveness.
§ 882.5896 Percutaneous nerve stimulator for substance use disorders.
(a)
Identification. A percutaneous nerve stimulator for substance use disorders is a device that stimulates nerves percutaneously to aid in the reduction of withdrawal symptoms associated with substance use disorders.(b)
Classification. Class II (special controls). The special controls for this device are:(1) The patient-contacting components of the device must be demonstrated to be biocompatible.
(2) Electromagnetic compatibility and electrical, mechanical, and thermal safety testing must be performed.
(3) Electrical performance testing of the device and electrodes must be conducted to validate the specified electrical output and duration of stimulation of the device.
(4) Software verification, validation, and hazard analysis must be performed.
(5) Sterility testing of the percutaneous components of the device must be performed.
(6) Shelf life testing must be performed to demonstrate continued sterility, package integrity, and device functionality over the specified shelf life.
(7) Labeling must include the following:
(i) A detailed summary of the device technical parameters;
(ii) A warning stating that the device is only for use on clean, intact skin;
(iii) Instructions for use, including placement of the device on the patient; and
(iv) A shelf life.