Jau-Ching Wu, Institute of Pharmacology, National Yang-Ming University, Peitou, Taiwan, and others report in The Spine Journal that patients undergoing spinal fusion surgery do not appear to have an increased risk of stroke compared with a matched cohort.
Wu et al wrote that stroke was a “rare but devastating” complication of all types of spinal surgery and added that despite case reports of stroke following spinal surgery, the actual incidence of the complication was not known. They said that patients at high-risk of cardiovascular disease undergo pre-operative screening to reduce the risk of post-operative complications and as a result, “some surgical candidates whose spinal diseases are amenable to surgical correction can be denied such procedures because of fear of these rare but unpredictable complications [ie, stroke].” Wu et al hypothesised, as the association between stroke and spinal fusion is not known, that spinal fusion would not increase the risk of stroke.
Using data from the National Health Insurance Research Database (NHIRD), Wu et al identified 2,249 patients who had undergone spinal fusion surgery between 2000 and 2005 and compared them with a group of matched controls (2,203). They found that spinal fusion had a lower, but not significantly, incidence of any, haemorrhagic and ischaemic stroke than the matched control group. There were 65 stroke events (eight haemorrhagic and 58 ischaemic) in the spinal fusion group compared with 74 stroke events (11 haemorrhagic and 64 ischaemic) in the control group. The authors reported, after adjusting for demographic characteristics, comorbidities, and medications, “the hazard ratios of the spinal fusion group were 0.89 (0.61–1.28), 1.36 (0.49–3.78), and 0.87 (0.59–1.28) for any, haemorrhagic, and ischaemic strokes.”
Wu et al speculated as to why patients who underwent spinal fusion had a lower (although insignificantly) incidence of stroke compared with the matched controls and commented that spinal fusion may lead to changes in modifiable risk factors for stroke. They commented: “For example, spinal fusion surgery often addresses instability and aims to improve walking, ambulatory function, exercise and other physical activities. Increased physical activity is believed to lower the risk of stroke.”
In their view, the benefit of their study is that it shows that stroke after spinal fusion surgery is unlikely and that “some high-risk patients should not be spared from surgical treatment for fear of stroke if otherwise prepared.” However, they added that further studies with more subjects and stratification of age groups (as younger patients in the spinal fusion group may have diluted age-related risks) are needed.