Objective evaluation and presentation of adverse outcomes, or complications, has lagged behind objective measurement and reporting of the beneficial effects of many surgical interventions, including cervical spine procedures. A complete evaluation of competing interventions for the same clinical condition would benefit from an understanding of the negative consequences of given treatment options, in addition to the potential benefits. Several initiatives are underway that should ultimately improve the ability of clinical researchers to record and report negative outcomes using validated, objective tools in a similar way to current reporting of positive outcomes. A first requirement of such efforts is a common definition of terms. Recently, the traditional term complication has been challenged as being too narrow, with a suggested substitution of the phrase adverse event. A complication is defined as “a morbid process or event occurring during a disease that is not an essential part of the disease, although it may result from it or from independent causes” (1,2). Adverse event is a broader term, in the sense that not all adverse events result in a complication for the patient. Adverse events are defined as episodes that may affect patient outcome or that may require intervention, further diagnostic tests, or monitoring (2, 3, 4 and 5). Thus, adverse events may increase the cost and duration of a given patient care episode without ultimate negative consequences for the patient.

Considering these definitions, several additional questions arise. For example, there are adverse effects that are expected results of certain procedures, and which therefore do not require further evaluation or treatment in the majority of patients. Such adverse outcomes should be seen as inherent to a given treatment and thus do not fit well within these definitions of complication or adverse event. Examples of such outcomes include functional limitations due to cervical stiffness following fusion or laminaplasty procedures (6, 7 and 8), local pain at an autograft bone donor site, or most cases of early dysphagia or dysphonia after a ventral cervical procedure. These surgical impacts have negative effects for patients but are in most cases an expected result of the surgical procedure performed. In general, they do not relate to technical or management errors nor are they rare. Rather, as a direct result of the surgical manipulation, they must be accepted as an expected trade-off in order to obtain the intended benefits of the intervention. We suggest the term collateral outcome for such expected negative side effects of surgery.

The concept of negative outcomes should also be expanded still further from most current definitions to include impacts not only to the individual patient but also to health care organizations and greater society. As indicated in the above definition, adverse events may have limited
effect on the patient undergoing the procedure beyond lengthening their recovery or hospitalization or requiring additional diagnostic tests. In such cases, the negative consequence of the adverse event may be exclusively financial and may be primarily borne by the hospital, a commercial insurer, or by a government agency, rather than by the patient themselves. Increasingly, greater costs incurred in one procedure may reduce health care resources available to other patients or even reduce funding available to initiatives outside of the health care arena. Given current economic trends, it is increasingly important to consider costs of given procedures as negative impacts and to weigh these in decision-making regarding the relative value of various potential interventions.

This chapter explores the current state of reporting of adverse events, both in cervical spine procedures, and more broadly in orthopaedics and other medical subspecialties. We also consider ongoing efforts to develop objective, repeatable, and validated methods to measure and report adverse events. This includes a review of work that has already been completed as well as a discussion of further appropriate steps for such efforts.