420 www.anesthesia-analgesia.org August 2014 • Volume 119 • Number 2 Copyright © 2014 International Anesthesia Research Society DOI: 10.1213/ANE.0000000000000234 I ntraoperative and postoperative morbidity play the most important roles in determining the quality of life and functional outcome of surgical patients and have a major impact on the overall cost-effectiveness of surgi- cal treatments. 1–3 Preoperative risk assessment scores are designed to help patients and clinicians in anticipating operative risks before surgery. Several preoperative scores and models have been developed and used to predict oper- ative outcome, but their widespread use has been limited by their poor speciicity and sensitivity. 4 A few subspecialties in surgery have succeeded in designing predictive preop- erative models; the European System for Cardiac Operative Risk Evaluation (EuroSCORE) risk stratiication system, for instance, is widely used in assessing the risk of patients scheduled for cardiac surgery. 5 Similarly, ASA physical status classiication system has been a useful assessment score in predicting outcome in major abdominal surgery as well as in renal cell carcinoma surgery. 6,7 Moreover, the ASA physical status classiication system predicts the out- come of general and vascular surgery as well as spinal sur- gery patients, because patients with higher ASA physical status grades have a higher risk of morbidity. 8,9 Recently, a systematic review of the risk stratiication tools for pre- dicting morbidity and mortality in a heterogenous cohort of surgical patients (noncardiac/nonneurological) sug- gested that the most promising risk predictors were the Portsmouth-Physiology and Operative Severity Score for the enUmeration of Mortality (P-POSSUM) and the Surgical Risk Scale. 10 The clinical relevance of preoperative risk assessment scores in predicting the neurological or overall outcome of cranial neurosurgery patients has been poorly studied. Given that the average age of neurosurgical patients and the prevalence of age-related comorbidities are constantly increasing, preoperative risk assessment scores could potentially help to identify high-risk patient groups in cra- nial neurosurgery. 11,12 Addressing this issue, the search strategy in this system- atic review was based on a speciic question “What is the evidence for the use of risk assessment scores in elective cra- nial neurosurgery?” In addition to summarizing the avail- able evidence, we discuss the strengths and weaknesses of BACKGROUND: Preoperative risk scores are designed to guide patient management by provid- ing a means of predicting operative outcome. Several risk scores are used in neurosurgery, but studies on their clinical relevance are scarce. Therefore, it is not clear whether these risk scores are beneicial or helpful in predicting outcome after elective cranial neurosurgery. In this review, we summarize the current scientiic evidence for using preoperative risk scores in elec- tive cranial neurosurgery. METHODS: A systematic review of the MEDLINE, Embase, and PubMed databases in November 2013 yielded 25 relevant studies with a minimum of 30 patients per study. The studies evalu- ated the value of the preoperative ASA physical status classiication, the Karnofsky performance score (KPS), the Charlson comorbidity score, the modiied Rankin Scale and the sex, KPS, ASA physical status classiication, location, and edema (SKALE) score in assessing postop- erative outcome in cranial neurosurgery. Surgery-related and nonsurgical complications were assessed separately whenever reported in the original article. For this purpose, the studies were placed into 4 categories based on the reported outcome: surgery-related outcome, non- surgical outcome, morbidity, and mortality. The Preferred Reporting Items for Systematic reviews and Meta-analyses guidelines for systematic reviews were followed. RESULTS: KPS has the strongest support in the literature for predicting surgery-related out- comes. There is no strong support in the literature for the use of any preoperative scores in predicting nonsurgical outcomes after elective craniotomies. KPS and ASA physical status clas- siication seem to predict early (≤ 30-day) morbidity of intracranial tumor patients. The Charlson comorbidity score may be applicable in predicting mortality of elective intracranial aneurysm patients. Only 4 studies were prospective in design. CONCLUSIONS: Large prospective studies are needed to validate the use of the reviewed risk scores in elective cranial neurosurgery. It appears, however, that the patient’s preoperative physical and functional status can be used to predict the short- and long-term outcome in elec- tive cranial neurosurgery. (Anesth Analg 2014;119:420–32) Evidence for the Use of Preoperative Risk Assessment Scores in Elective Cranial Neurosurgery: A Systematic Review of the Literature Elina Reponen, MD,* Hanna Tuominen, MD, PhD,* and Miikka Korja, MD, PhD†‡ From the Departments of *Anesthesiology and Intensive Care Medicine, and †Neurosurgery, Helsinki University Central Hospital, Helsinki, Finland; and ‡Australian School of Advanced Medicine, Sydney, Australia. Accepted for publication March 5, 2014. Funding: No funding was received. The authors declare no conlicts of interest. Reprints will not be available from the authors. Address correspondence to Elina Reponen, MD, Department of Anesthesi- ology and Intensive Care Medicine, Helsinki University Central Hospital, P.O.Box 266, 00029 HUS, Helsinki, Finland. Address e-mail to elina.reponen@ helsinki.i. REVIEW ARTICLE E