Patterns in neurosurgical adverse events: intracranial neoplasm surgery
Authors: Wong Judith M. , Panchmatia Jaykar R. , Ziewacz John E. , Bader Angela M. , Dunn Ian F. , Laws Edward R. , Gawande Atul A. 
Published: November 2012

Object
Neurosurgery is a high-risk specialty currently undertaking the pursuit of systematic approaches to measuring and improving outcomes. As part of a project to devise evidence-based safety interventions for specialty surgery, the authors sought to review current evidence in cranial tumor resection concerning the frequency of adverse events in practice, their patterns, and current methods of reducing the occurrence of these events. This review represents part of a series of papers written to consolidate information about these events and preventive measures as part of an ongoing effort to ascertain the utility of devising system-wide policies and safety tools to improve neurosurgical practice.

Methods
The authors performed a PubMed search using search terms “intracranial neoplasm,” “cerebral tumor,” “cerebral meningioma,” “glioma,” and “complications” or “adverse events.” Only papers that specifically discussed the relevant complication rates were included. Papers were chosen to maximize the range of rates of occurrence for the reported adverse events.

Results
Review of the tumor neurosurgery literature showed that documented overall complication rates ranged from 9% to 40%, with overall mortality rates of 1.5%–16%. There was a wide range of types of adverse events overall. Deep venous thromboembolism (DVT) was the most common adverse event, with a reported incidence of 3%–26%. The presence of new or worsened neurological deficit was the second most common adverse event found in this review, with reported rates ranging from 0% for the series of meningioma cases with the lowest reported rate to 20% as the highest reported rate for treatment of eloquent glioma. Benign tumor recurrence was found to be a commonly reported adverse event following surgery for intracranial neoplasms. Rates varied depending on tumor type, tumor location, patient demographics, surgical technique, the surgeon's level of experience, degree of specialization, and changes in technology, but these effects remain unmeasured. The incidence on our review ranged from 2% for convexity meningiomas to 36% for basal meningiomas. Other relatively common complications were dural closure–related complications (1%–24%), postoperative peritumoral edema (2%–10%), early postoperative seizure (1%–12%), medical complications (6%–7%), wound infection (0%–4%), surgery-related hematoma (1%–2%), and wrong-site surgery.
Strategies to minimize risk of these events were evaluated. Prophylactic techniques for DVT have been widely demonstrated and confirmed, but adherence remains unstudied. The use of image guidance, intraoperative functional mapping, and real-time intraoperative MRI guidance can allow surgeons to maximize resection while preserving neurological function. Whether the extent of resection significantly correlates with improved overall outcomes remains controversial.

Discussion
A significant proportion of adverse events in intracranial neoplasm surgery may be avoidable by use of practices to encourage use of standardized protocols for DVT, seizure, and infection prophylaxis; intraoperative navigation among other steps; improved teamwork and communication; and concentrated volume and specialization. Systematic efforts to bundle such strategies may significantly improve patient outcomes.