The Underreporting /
Tip of the Iceberg Problem

Cannula detachment is dramatically under-reported. Published incident rates capture only those cases that resulted in formal litigation or regulatory notification. The reality on the operating theatre floor is very different: events are absorbed into the surgical record, attributed to other causes, or simply normalised as part of the unpredictability of surgery.

Surgeons rarely report these events. The implicit assumption is always that the cannula was not tightened properly - operator error - and there is no neutral channel that captures the failure as what it actually is: a recurring equipment-junction problem. The result is that surgeons absorb each event as "one of those things," an unavoidable part of the unpredictability of surgery. A true Russian roulette of harm.

This is a regulatory orphan. If the cannula breaks, a report goes to the manufacturer and the regulator. If the syringe snaps, the same. But if the junction between the two fails - which is the actual failure mode - no report is triggered, no manufacturer is informed, no regulator is notified. The failure happens in a gap between products, and the reporting system has no category for it. There is no recognition, and no action ensues.

This is why surgeon-experience data tells the truer story. In a published survey of 551 ophthalmic surgeons, 84% had personally experienced cannula dislocation, 78% had seen the patient harmed as a result, and 50% reported ocular damage from the last episode they witnessed. These are not rare events. They are everyday risks that have been hidden in plain sight.

Waiting for the published incident data to "catch up" is not a safety strategy. The data that matters is already in front of us - in every surgeon's direct experience, and in every patient who has lost vision because a piece of equipment failed in a way no one was required to report.