A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was 'Is cerebrospinal fluid (CSF) drainage of benefit in patients undergoing surgery on the descending thoracic aorta or thoracoabdominal aorta?' Altogether 1177 papers were found using the reported search, of which 17 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Ten of 13 studies demonstrate significant neurological protection from CSF drainage (± additional adjuncts), with two further papers showing no significant difference between patients who had or had not had CSF drainage and one study unable to provide any conclusions. For patients having surgery on the thoracic aorta or thoracoabdominal aorta CSF drainage, maintaining pressures <10 mmHg (P < 0.03), in conjunction with other neuroprotective strategies, minimizes the risk of neurological sequelae when compared with patients treated with similar adjuncts but without CSF drainage. The majority of studies used additional neuroprotective strategies, including cooling and reattachment of the intercostal arteries as adjuncts to CSF drainage. Logistic regression curves demonstrated that the longer the ischaemia time, the greater the benefit from CSF drainage (P < 0.04). Four papers observed complications of CSF drainage, of which the main complications were: catheter occlusion or dislodgement, headache, meningitis and subdural haematoma. Overall, CSF drainage does offer a neuroprotective benefit; preventing paraplegia if CSF pressures are maintained <10 mmHg.