Introduction: Neurosurgical patients undergoing craniotomies are at high risk for developing venothromboembolism (VTE), with reports of an incidence of DVTs up to 25% and a mortality rate from PE between 9-50%. The Caprini risk assessment model is a method to stratify the risk of post-operative thromboembolic events (0 = very low risk; 1-2 = low risk; 3-4 = moderate risk; 5 or greater = high risk). Our goal is to validate the use of this model to assess the risk of VTE events in neurosurgical patients undergoing cranial procedures.

Methods: We performed a retrospective review of those patients undergoing cranial procedures at our institution between July 2015 and June 2016. Inclusion criteria were all cranial procedures and available 30-day post-operative follow up. Exclusion criteria were the presence of VTE prior to or at the time of surgery and intra-operative and immediate post-operative death. The Caprini score, number of VTE events, and timing of chemoprophylaxis were recorded for each patient.

Results: 197 patients met the inclusion criteria (Fig 1). The VTE incidence was 8.6%. The mean Caprini score was 6.6 (range 1 - 18) for patients without VTE and 9.3 (range 3 - 14) for patients with VTE (Fig 2). There was a significant correlation between development of VTE and Caprini score (Spearman rho 0.25, p<0.001) (Fig 3). Not all patients were started on chemoprophylaxis due to various factors.

Conclusions: This is the first report evaluating the Caprini risk assessment model in a neurosurgical population undergoing cranial procedures. It validates the Caprini model as a measure of post-operative risk of developing VTE. Patients with higher scores were at greater risk of post-operative VTE. The cutoff score was 3.

Patient Care: Our research aims to improve patient care by using a risk assessment model to estimate the post-operative risk of VTE in patients undergoing cranial procedures on which decisions about VTE prophylaxis can be made.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Familiarize oneself with the Caprini risk assessment model 2) Understand the risks of VTE in relation to cranial neurosurgery

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