Clinical quality management includes written definition of standard procedures, the use of checklists, and regular audits comparing results with benchmarks. The targets of quality management are safety and efficacy. Because physicians have only recently accepted the need for such processes, however, the principal ideas of safety management have been taken from other fields, such as transportation and construction.

Safety concepts adopted in medicine have been profoundly influenced by the ideas of James Reason, who hypothesized that most accidents can be traced to one or more of four levels of failure:

In this model, an organization’s defenses against failure are modeled as a series of barriers. Individual weaknesses in individual parts of the system are continually varying in size and position. The system as a whole produces failures when all individual barrier weaknesses align, permitting “a trajectory of accident opportunity” in which a hazard passes through all of the holes in all of the defenses, leading to a failure [1]. In the causal sequence of human failures that leads to an accident or an error, the model includes both active failures and latent failures. The concept of active failures encompasses the unsafe acts that can be directly linked to an accident, such as pilot errors in aircraft accidents. The concept of latent failures is particularly useful in the process of aircraft accident investigation, because it encourages the study of contributory factors in the system that may have lain dormant for a long time until they finally contribute to an accident. Latent failures span the first three levels of failure in Reason’s model: organizational influences, unsafe supervision, and preconditions for unsafe acts. Organizational influences encompass such things as reduced expenditures on pilot training in times of financial austerity. Unsafe supervision encompasses such things as pairing two inexperienced pilots together on a flight into known adverse weather at night. Preconditions for unsafe acts include fatigued air crew or improper communications practices.

The same analyses and models apply in the field of healthcare, and many researchers have provided descriptive summaries, anecdotes, and analyses of Reason’s work in the field. For example, a latent failure could be the similar packaging of two different prescription drugs that are then stored close to each other in a pharmacy. Such a failure would be a contributory factor in the administration of the wrong drug to a patient. Such research has led to the realization that medical error can be the result of “system flaws, not character flaws,” and that not only ignorance, malice, or laziness causes error.

Reason’s work resulted primarily in a culture of defining and periodically reviewing clinical processes. Use of surgical checklists and the idea of an anonymous critical incident reporting system (CIRS) resulted from these ideas. A CIRS is not practical in a department of neurosurgery because anonymity cannot be guaranteed, in contrast to a department of radiology or anesthesiology, for example, or in the context of multicentric registries. The use of surgical checklists became popular with the introduction and validation of the World Health Organization (WHO) checklist [2]. We have been using similar checklists for more than 20 years in order not to forget preoperative or postoperative details.

Established processes to regularly verify the safety and efficacy of clinical—and particularly invasive—procedures are now expected by patients and health organizations. Although aspects of managing aneurysms and subarachnoid hemorrhage (SAH) differ from other subspecialties, it remains debatable how far quality management should be separated from the rest of neurosurgery or remain integrated in a common frame. We have regularly analyzed complications and discussed them within a common morbidity and mortality (M&M) conference for the past two decades. While trying to study the effect of these recurring audits on clear quality indicators, we realized that the main point of these audits is teaching or communicating a culture of good clinical care. M&M conferences are typical examples of case-based teaching seminars. Therefore, issues that every neurosurgeon and neurosurgical resident should know at least to some degree should be discussed together. In contrast, the degree to which separate subspecialties such as radiosurgery or functional neurosurgery can be appropriately covered in a common frame remains open to question.

Safety of treatments always has been the primary focus of quality audits. Safety parameters are simple to define in terms of complications and rates of case morbidity and fatality. Effectiveness of treatment is usually included in the analysis, as reflected by surrogate parameters such as completeness of tumor removal or aneurysm elimination. These surrogate parameters are not evidence proved, and the relevant outcome parameters such as survival rates in patients with malignancies or quality of life in patients with unruptured aneurysms realistically cannot be considered in a quality audit.

Despite the now traditional role of regular M&M conferences within resident training programs, their effect as a tool to improve quality has remained hypothetical. In more recent years, with a greater focus on quality management, these conferences have been increasingly considered to be an audit and, therefore, an instrument to identify systemic flaws. Methods of reporting cases to be discussed, methods of analysis, classification of morbidity, and criteria for consequences to improve the processes vary widely.