A system of alerts on the medical records of patients who may have had the fatal brain disease CJD was given up five years before surgery on an undetected case led to others being put at risk.
The revelation is contained in an unpublished report by the Health and Disability Commissioner at the time, Ron Paterson. He did not find fault with the surgeon who treated the woman, nor the Auckland District Health Board, but he did express concern about the alert system.
In a letter to complainant Monique Lambermon - mother of Danielle, one of the 43 patients potentially exposed to Creutzfeldt-Jakob disease through sterilised and re-used instruments - he said it was concerning that the DHB, prior to quitting the alert system, had apparently not conducted a review of "the level of risk, the effectiveness of alerts and other relevant factors".
In 2001, the health board's neurosurgery service began placing alerts on the files of new neurosurgery admissions who had also been admitted for neurosurgery before 1987. This was because there had been cases, including two reported in New Zealand, of patients developing CJD after a potentially infected product called Lyodura was implanted during neurosurgery, to patch part of a membrane covering the brain and spinal cord.
In 2002-03 the DHB introduced a new electronic records system but the alert system for CJD risk "was not carried over", Mr Paterson said.
Despite expressing concern about the lack of a "considered decision" over this, he noted there had been no cases of equipment-related CJD transmission worldwide since the 1970s. His medical adviser, Professor Grant Gillett, did not know of any other transtasman neurosurgical units that had such an alert system.
The DHB told Mr Paterson that alerts could be compromised by the quality of their information, the systems for updating them and clinicians' ability to interpret them correctly.
The surgeon who treated the infected woman in March 2007 had also treated her in 1984, when a Lyodura patch was implanted.
The surgeon told the commissioner that although the index patient had been known to him since 1984, "he could not possibly have remembered details of all of the patient's operations over a 23-year period. "It did not occur to him that the patient may have received a Lyodura graft in 1984.
"Clinically, there was no suspicion of CJD when the patient re-presented in 2007, and [the surgeon] was not aware of any reported cases of CJD following implantation of Lyodura in New Zealand.
"[He] stated that many patients have multiple operations, and it is not usual practice to access all previous surgical notes. He noted that old notes can be incorrect or misleading, particularly with the evolution of imaging technology."
Mr Paterson said: "I do not think it is reasonable to expect [the surgeon] to recall the index patient's surgical history of 23 years earlier, even though it was he who performed that surgery.
"I agree with Professor Gillett that under the circumstances, [the surgeon's] initial failure to consider the possibility of CJD in the index patient was understandable."
The DHB has put clinical alerts with supporting documentation on the 43 affected patients' electronic records.
DHB spokeswoman Dr Margaret Wilsher, in a written response to the Herald, chose not to answer its question on why the 2001 alert system was not carried over, saying: "We accept the commissioner's decision in that matter." Martin Johnston