Spinal drainage complications after aortic surgery.

Abstract

INTRODUCTION\nSpinal drain (SD) placement is an adjunct used in open and endovascular aortic surgery to mitigate the risk of spinal cord injury. SD placement can lead to subdural hematoma and intracranial hemorrhage (SDH/ICH). Previous studies have highlighted a correlation between incidence of SDH/ICH and amount of cerebrospinal fluid (CSF) drained. We have two philosophies of SD management in our institution. One protocol allows fluid removal for pressure > 10 cm H2O with no volume restriction. A second, similar protocol restricts CSF drainage to < 25 ml/hr. We examined SD complications and the influence of volume restriction.\n\n\nMETHODS\nPatients were identified according to the Current Procedure Terminology codes (CPT) for SD placement, thoracic endovascular aortic repair, fenestrated/branched endovascular aortic repair, endovascular abdominal aortic repair, open thoracic or thoracoabdominal aortic repair between January 1, 2012 and December 31, 2015. Patients demographics included age, gender, race, body mass index and comorbidities such as hypertension, chronic obstructive pulmonary disease, stroke, transient ischemic attack, diabetes mellitus, bleeding disorder and connective tissue disorders. Management protocol was divided as volume independent (VI) or volume dependent (VD) by physician order. Postoperative complications related to the SD were noted.\n\n\nRESULTS\nWe identified 948 patients who had a SD placed during the study period, 473 were done prior to aortic surgeries. 364 patients (77%) underwent endovascular aortic surgery. Mean age at the time of procedure was 67.2 years and 66% of patients were male. 39 patients (8.3%) were noted to have connective tissue disorders. Bloody SD placement occurred in 14 patients (3.1%) requiring rescheduling of the operation. SDH/ICH occurred in 11 patients (2.3%), post-operative blood tinged SD output in 94 patients (19.9 %) and 22 patients (4.7 %) had a CSF leak after SD removal. The incidence of SDH/ICH was not affected by the management protocol (2.6% VI Vs 2.0% VD, p=0.66), while the incidence of postoperative blood tinged SD output was significantly higher in the VI group (25.1% VI vs 15.0% VD, p=0.006). Perioperative low dose aspirin (81 mg) and prophylactic subcutaneous heparin did not increase the incidence of SDH/ICH. Post-operative thrombocytopenia was found to be associated with higher incidence of SDH/ICH (median 86,000 Vs 113,000, p=0.002).\n\n\nCONCLUSION\nSevere complications of SD placement (SDH/ICH) occurs in 2.3% of SD patients undergoing aortic surgery and the risk is higher in the setting of post-operative thrombocytopenia. SD volume limitation, blood tinged SA drainage, antiplatelet medication and low dose heparin do not affect the risk of SDH/ICH. The risks of spinal drains for aortic surgery should be balanced against potential benefits.