Cerebrospinal fluid (CSF) drainage is a key component in the treatment of spinal cord injury but the evidence that prophylactic drainage decreases such injury during endovascular repair (EVAR) is “at best weak,” Gustavo Oderich (Mayo Clinic, Rochester, USA) told this year’s Critical Issues America annual meeting (7–8 February, Miami, USA).
Last year, Oderich and colleagues published a study in the Journal of Vascular Surgery that discovered severe complications from placement of cerebrospinal fluid drains (CSFD) during first-stage thoracic endovascular aortic repair (TEVAR) and fenestrated-branched endovascular repair (F-BEVAR) of pararenal and thoracoabdominal aortic aneurysms (TAAAs). At that point, Oderich and colleagues found they were occurring at an “alarming rate” in their prospective, non-randomised study.
In this latest presentation, Oderich sought to answer the question: “Are preoperative spinal drains necessary?” He opened by considering early research in the field: “The story always starts in the early 1990s and this is the first prospective randomised trial,” referring to a study carried out by E Stanley Crawford that randomised 98 patients with extent I to extent III TAAAs.
“It is amazing to see the very high rate of spinal cord injury at 30% at that point and how much improvement we have made over the years in open surgical techniques,” he said. “Of course, we are taught we should use a spinal drain for every extensive thoracic coverage, and that is actually largely based on another paper, by Joseph Coselli, another prospective randomised study of 145 patients with extent I and II TAAAs. They had a more liberal use of drainage with an average of 64mL intraoperatively and 260mL postoperatively for two days, or two additional days in those patients who had sustained injury.”
Oderich went on: “There was a remarkable improvement in spinal cord injury. That is, 2.6% with drainage and 13% without drainage. Based on that, we started using drains and a lot of other agents, and in fact none have been shown with level one data or even close to level one data to be beneficial. A lot of them have been incorporated in the late learning curve of centres and therefore we become biased and assume these things are essential to prevent spinal cord injury.”
Considering the rates of injury in the endovascular literature, Oderich commented: “It is appalling to see the wide range of 2–50% and the rate of paraplegia of 0–29% in these publications.” Oderich pointed to possible variances in honesty when reporting, going on to opine: “But I think that in a number of cases people mix pararenals extent IV with extent I–III TAAAs.” Most importantly, he noted that “there is no prospective randomised trial.”
Oderich then turned his attention to another, unpublished piece of research in which he was one of the investigators that delivered further interesting findings. “We had one mortality among 232 consecutive cases,” he explained. “We had an overall rate of spinal injury of 4%. Note that in group one and two, [the figure] was 10% but note that at the end of the day, there was a 2% rate of persistent paraplegia,” adding, “I think what was disappointing on this paper was we found out that 20% of our paraplegias were actually due to spine haematomas.”
Oderich continued: “We then looked at the literature and indeed there is this systematic review with 4,717 patients, 6,593 procedures, open and endovascular, 34 studies and note here that the rate of any complications was 10%. The most frequent one is headache requiring a blood patch but also very serious complications such as spine haematomas.”
According to Oderich, there is a “rationale” for prophylactic drainage: “We assume it prevents spinal cord injury and that placement of drains after the repair are potentially risky because of possible coagulopathy, and they are not always possible to do. Probably over 90 or 95% of the patients actually do not need the drain to begin with.
There are also projected unnecessary risks, Oderich remarked. “Not all the drains work. How many times have you had a patient paraplegic with a drain? The drain is actually not draining or is clogged. Or it leaks. Not all the spinal cord injuries improve with a drain. How many times have you had a patient with a drain wake up paraplegic or became paraplegic and did not improve?” he questioned.
Oderich added: “We know that 10% of the drains cause serious complications. I can tell you there is nothing like an unhappy patient the next day when you tell them they are going to lay flat for two days or maybe with some improved drains they can move a little more.”
