Any operation has the risk of complications. There can be blood loss, infection, poor wound healing, and even death. Most of these problems never happen. The most common risk with anterior lumbar surgery (ALS) is blood vessel compression, tears, or accidental cuts.
A recent study of 1,310 patients reported a low (less than two percent) rate of blood vessel injury. Most of these problems were seen and treated right away. Women having a lumbar fusion at L45 seemed to be at greatest risk for these types of problems.
Overall the operation is considered quite safe in the hands of a good vascular surgeon.