Prophylactic cerebrospinal fluid drainage in aortic surgery: enhancing neurological outcomes

Spinal cord ischemic injury (SCI) is one of the most feared complications following thoracic and thoracoabdominal aortic repair procedures[1]. The disruption of blood supply to the spinal cord can result in paraplegia or paraparesis, significantly impacting the quality of life and recovery of patients undergoing these complex surgeries[2]. Cerebrospinal fluid drainage (CSFD) has emerged as a critical intervention to reduce spinal cord pressure and enhance spinal cord perfusion, thereby mitigating the risk of SCI[3]. Despite its potential benefits, concerns regarding CSFD-related complications have led to ongoing debate about its prophylactic use in aortic repair, particularly in thoracic endovascular aortic repair (TEVAR). A recent study by Ohashi et al evaluated the safety and validity of selective CSFD in both open and endovascular aortic repair, analyzing outcomes in 450 patients who underwent aortic surgery[4]. Among these, 147 patients underwent CSFD, with 135 receiving it prophylactically and 12 therapeutically after SCI. The study found that CSFD-related complications were observed in 9.6% of patients, with severe complications occurring in only 0.74% of the cases. Prophylactic CSFD showed a significant reduction in SCI incidence, with a rate of 1.5% in patients who received CSFD compared with 4.8% in those who did not. Notably, inverse probability-weighted analysis confirmed that prophylactic CSFD effectively reduced the incidence of SCI in elective TEVAR cases (P = 0.028), demonstrating the potential benefit of selective CSFD in high-risk patients. The primary rationale for using CSFD in aortic repair is to reduce cerebrospinal fluid pressure, thereby enhancing spinal cord perfusion pressure (SCPP)[5]. Maintaining adequate SCPP is crucial for preventing ischemic damage to the spinal cord, especially during extensive aortic interventions that involve prolonged periods of aortic cross-clamping or reduced blood flow[1,6,7]. CSFD achieves this by lowering the pressure gradient across the spinal cord, allowing for improved blood flow through the collateral networks that supply the spinal cord[8]. Research has shown that when SCPP falls below a critical threshold, the risk of spinal cord injury increases dramatically[9,10]. By reducing cerebrospinal fluid pressure, CSFD helps maintain SCPP above this threshold, thus protecting the spinal cord during and after aortic surgery[11,12]. This mechanism is particularly vital in TEVAR, where the risk of spinal cord ischemia is heightened due to the potential for covering critical intercostal arteries that contribute to spinal cord blood supply[13]. The decision to use prophylactic versus therapeutic CSFD in aortic repair remains a topic of debate among clinicians. Prophylactic CSFD is typically employed in patients deemed at high risk for SCI based on factors such as extensive aortic coverage, previous aortic surgeries, or a history of spinal cord ischemia[14]. The potential advantage of prophylactic CSFD lies in its ability to preemptively lower cerebrospinal fluid pressure, thereby reducing the likelihood of SCI during the perioperative period. In contrast, therapeutic CSFD is initiated after the onset of SCI symptoms, with the aim of reversing neurological deficits[15]. While therapeutic CSFD can be effective in improving outcomes for patients who develop SCI, studies have indicated that patients receiving prophylactic CSFD often have better neurological recovery and fewer long-term deficits.[16-18] These findings suggest that early intervention through prophylactic CSFD may offer superior protection against SCI in high-risk patients undergoing aortic repair. Despite its efficacy in reducing the risk of SCI, CSFD is associated with potential complications. The most common complications include headaches, puncture-site leaks, and, less frequently, severe events such as intracranial hemorrhage, spinal hematoma, and infection[19,20]. The reported incidence of severe CSFD-related complications ranges from 2.5% to 5.1% in various meta-analyses, emphasizing the need for careful patient selection and adherence to drainage protocols to minimize these risks[19,21,22]. Studies have highlighted the importance of pressure- and volume-regulated drainage protocols to prevent complications such as intracranial hemorrhage[23,24]. Limiting cerebrospinal fluid drainage to less than 15 mL per hour and maintaining intracranial pressure below 13 cmH2O are recommended strategies to reduce the incidence of serious complications[23]. Additionally, avoiding CSFD in patients with coagulation disorders or those undergoing deep hypothermic circulatory arrest can further mitigate the risk of adverse events[25]. The use of CSFD as an adjunctive measure in aortic repair has significant clinical implications, particularly for patients undergoing complex aortic interventions who are at a high risk of SCI. Prophylactic CSFD offers a means of reducing the incidence and severity of spinal cord injury, thereby improving postoperative outcomes and reducing the burden of long-term neurological deficits. However, the decision to implement CSFD should be based on a thorough assessment of patient risk factors, surgical complexity, and potential benefits and risks. Future research should focus on refining CSFD protocols, identifying optimal patient selection criteria, and exploring adjunctive strategies that may enhance spinal cord protection, such as pharmacological agents and advanced monitoring techniques. As evidence continues to accumulate, the integration of CSFD into a standardized spinal cord protection protocol could play a pivotal role in reducing the incidence of SCI in aortic repair. In conclusion, Cerebrospinal fluid drainage remains a valuable tool for the prevention and management of spinal cord injury during aortic repair. As surgical techniques and perioperative management continue to evolve, CSFD will likely remain an integral component of spinal cord protection strategies, contributing to improved outcomes in patients undergoing aortic repair procedures.