FDA Warning Letter Breakdown: Complaint Backlogs, CAPA Blind Spots, and Risk Management Gaps at an Implantable Device Manufacturer
How unresolved quality system fundamentals cascade across complaints, CAPA, and design risk.
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On November 11, 2025, the FDA’s CDRH issued a warning letter to a device firm following an inspection conducted from June 24 through July 2, 2025, at the firm’s Saint Paul, Minnesota, facility. The firm manufactures the Esteem II Implantable Hearing System, a Class III implantable medical device.
Some warning letters read like checklists. This one doesn’t.
At first glance, it looks pretty familiar: open complaints, CAPAs that didn’t go far enough, risk files that weren’t kept current. But when you read it closely, what the FDA is really documenting is something we see over and over again in audits and mock inspections: known issues that were identified, discussed, and then quietly allowed to stall.
This firm had SOPs. It wasn’t about a single bad investigation or a one-off cleanroom event. The FDA lays out a pattern: complaints involving implantable devices and serious injury sitting open for months, environmental excursions without documented product impact assessments, and risk management files that never fully absorbed what the quality system was already signaling.
For implantable device manufacturers, that combination is especially risky. Complaints, CAPAs, environmental monitoring, and design risk are supposed to reinforce each other. When they don’t, the FDA sees a system that isn’t learning from itself.
We see the same dynamic play out during inspections. Teams are working hard, issues are being logged, meetings are being held, but ownership is blurring, decisions are getting deferred, and risk signals are losing urgency as they move from one system to the next.
That’s why this letter is worth unpacking. It shows how quickly routine quality system weaknesses can compound when follow-through breaks down.
Complaint handling failures (investigations that stalled, drifted, or never closed)
21 CFR 820.198(a) shows up at the top of basically every top device compliance problems list. In this case, the FDA’s initial and most detailed findings focus on the company’s failure to establish and maintain complaint-handling procedures despite having written SOPs in place. The FDA states they didn’t adequately implement its complaint-handling procedure to ensure that complaints were processed uniformly and in a timely manner.
The letter highlights three complaints involving serious injury, infection, or revision surgery, all of which remained open for extended periods.
Across these complaints, the FDA observed:
Investigations remaining open seven months or longer.
Engineering responsibility deferred across multiple review meetings.
Returned product analyses not performed in accordance with existing procedures.
Long gaps with no documented progress updates.
Available calibrated equipment not used.
Complaints remaining open at the close of the inspection.
The FDA also notes that the complaint SOP lacks specific timeliness requirements, even though other internal procedures describe how investigations should be conducted.
We often see complaint systems fail not because procedures are missing, but because no one truly owns forward momentum. Sometimes, complaint review boards meet regularly but defer decisions, especially engineering assignments. Other times, serious complaints are treated as “under investigation” indefinitely while teams wait for resources, equipment, or consensus. We also see:
Complaint files that technically remain “open” but show months of inactivity.
MDRs filed on time, creating a false sense of compliance while the underlying investigation stalls.
FDA investigators routinely focus less on whether a firm eventually closed a complaint and more on whether the timeline, ownership, and escalation made sense as the complaint unfolded.
Ask yourself:
Do your complaint procedures define clear expectations for investigation timelines, or do cases linger until someone escalates them?
When engineering investigations are required, is ownership assigned immediately and documented?
Can you show a month-by-month activity trail for every open serious-injury complaint?
If equipment or resources are unavailable, do you document alternate qualified approaches, or simply wait?
If the FDA asked today, could you confidently explain why your oldest open complaint is still open?
CAPA failures: cleanroom excursions without product impact assessment
Another common problem area is cited here: 21 CFR 820.100(a).The FDA found issues with the CAPA system, specifically its response to high particulate counts in ISO Class 8 cleanrooms. Procedures were not adequately implemented for two critical CAPAs tied to extended periods of nonconforming environmental conditions.
FDA describes two particulate excursions—one in 2022 and one in 2024—both identified through third-party monitoring. In both cases, the FDA states that:
ISO Class 8 particulate limits were exceeded.
Nonconforming conditions persisted for extended periods.
No Health Hazard Evaluation (HHE) was conducted.
No documented assessment evaluated the impact on products manufactured during the affected windows.
This is another recurring pressure point in audits. Many firms treat environmental excursions as facilities issues, not product-risk events. Common failure modes we see include:
CAPAs focused on restoring cleanroom conditions without formally assessing what was manufactured while conditions were out of spec.
Reliance on assumptions like “no sterility failures occurred” in place of structured HHEs.
Product impact assessments that are informal, undocumented, or retroactively justified.
CAPAs that close without ever answering the investigator’s implicit question: “How do you know patients weren’t affected?”
The FDA expects firms to demonstrate not only that conditions were corrected but also that patient risk was explicitly evaluated and documented.
Ask yourself (anyone running cleanrooms):
When environmental monitoring excursions occur, do you automatically trigger a formal HHE, or is it optional?
Can you clearly map every product and lot manufactured during nonconforming conditions?
Do your CAPAs investigate why risk assessment failed, not just what failed?
If qualified staff missed the need for an HHE, do you examine training, judgment, and escalation criteria?
Would an FDA investigator find a clear, documented narrative explaining why patient risk was or was not present?
Risk management problems around infection severity, missing hazards, and endotoxin oversight
The final section of the letter addresses the firm’s failure to adequately implement design validation and risk management procedures for a sterile implantable device, which is spelled out in 21 CFR 820.30(g).