Clinical Neurology and Neurosurgery 130 (2015) 150–154 Contents lists available at ScienceDirect Clinical Neurology and Neurosurgery jo ur nal homep age: www.elsevier.com/lo cate/clineuro Risk factors for cranial nerve deficits during carotid endarterectomy: A retrospective study Parthasarathy D. Thirumala a,c,* , Harsha Kumar a , Marnie Bertolet d , Miguel E. Habeych a , Donald J. Crammond a , Jeffrey R. Balzer a,b a Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, USA b Department of Neuroscience, University of Pittsburgh, Pittsburgh, USA c Department of Neurology, University of Pittsburgh Medical Center, Pittsburgh, USA d School of Public Health, University of Pittsburgh, Pittsburgh, USA a r t i c l e i n f o Article history: Received 20 October 2014 Received in revised form 22 December 2014 Accepted 29 December 2014 Available online 5 January 2015 Keywords: Cranial nerve injury Carotid endartectomy Electroencephalography Somatosensory evoked potentials Intraoperative neurophysiological monitoring a b s t r a c t Background: Cranial nerve deficits during CEA are a known complication. The purpose of this study is to evaluate if significant changes in somatosensory evoked potentials and electroencephalography increase cranial nerve deficits during CEA. Procedures: This is an observational retrospective case–control study analyzed with data collected from patients who underwent CEA at the University of Pittsburgh Medical Center. Five hundred and eighty- seven patients were included in the final analysis. Due to the small number of cranial nerve deficits and the comparatively large number of potential covariates, we used a regression analysis with Bayesian shrinkage. Findings: Analysis was performed on 587 patients, of which a total of 11 (1.8%) cases of cranial nerve deficits were recorded. The marginal mandibular branch of the facial nerve was injured in nine (81%) patients and hypoglossal nerve was injured in two (19%) patients. Of the 11 patients, 9 cases resolved by the time of discharge, the 2 cases that persisted both were injuries to the facial nerve. Multivariate analysis using Bayesian shrinkage showed that after adjusting for all risk factors only IOM changes increased the risk of cranial nerve deficits (OR 38.47, 95% CI 7.73, 191.42). Conclusions: Cranial nerve injury is 38 times more likely in patients who experienced a change in IOM during CEA shunt. Future studies examining the effect of stretch and the degree of retraction on the CN might be more helpful in reducing cranial nerve deficits. © 2015 Elsevier B.V. All rights reserved. Carotid endarterectomy (CEA) is the procedure of choice to prevent stroke in symptomatic and asymptomatic patients with carotid artery stenosis [1–3]. Cranial nerve deficits during CEA is a known complication and commonly involves injury to the marginal mandibular nerve [4] resulting in inability to express emotions [5]; recurrent laryngeal nerve, resulting in vocal cord paralysis [6]; the hypoglossal nerve resulting in tongue weakness [7]; and the greater auricular nerve [4,8] resulting in numbness around the ear. Reports of the injury to glossopharyngeal nerve resulting in pha- ryngeal weakness, superior laryngeal nerve resulting in change in * Corresponding author at: Center for Clinical Neurophysiology, Department of Neurologic Surgery, University of Pittsburgh Medical Center, UPMC Presbyterian- Suite-B-400, 200 Lothrop Suite, Pittsburgh, PA 15213, USA. Tel.: +1 412 648 2582; fax: +1 412 383 9899. E-mail address: thirumalapd@upmc.edu (P.D. Thirumala). pitch of the voice [7], spinal accessory nerve resulting in difficulty with moving the head, and cervical sympathetic chain resulting in Horner’s syndrome have also been documented [4,8]. The rate of cranial nerve deficits reported varies widely from 3% to 23% [8,9,4,10,11,6,12–14] in the literature with variations secondary to the type of research study [4], surgical technique [15], the year the procedure was performed [8] and increased awareness of the cra- nial nerve damage [8]. Though most of these cranial nerve deficits are transient it can lead to decreased quality of life [16] in addi- tion to increased length of stay (LOS) after the CEA [17]. Decreased LOS can have a significant impact on the cost-effectiveness of CEA [18]. Clinical pathways for patients undergoing CEA can signifi- cantly reduce the LOS and its cost [18]. Identifying risk factors and strategies to prevent cranial nerve deficits can potentially decrease LOS and the overall cost of CEA. Transient cranial nerve deficits after CEA could be secondary to inadvertent stretch and retraction of the cranial nerve (CN) [4], http://dx.doi.org/10.1016/j.clineuro.2014.12.017 0303-8467/© 2015 Elsevier B.V. All rights reserved.