No surgery is without risk, even for a healthy person. Your surgeon will discuss the risks and complications with you.
General complications:

• Allergic reaction to drugs, anaesthetic agents, blood transfusions and products
• Bleeding
• Infections
• Stroke
• Death

Specific complications related to spine surgery:

• Nerve or spinal cord damage, which can result in paralysis, numbness and/or limb weakness
• Persistent pain (or other abnormal sensations)
• Infection of the surgical wound
• Pressure ulcers/abrasion (position related)
• Leakage of cerebrospinal fluid (CSF)
• Bladder and bowel changes
• Spinal cord/nerve injury
• Visual impairment
• Need for additional unplanned procedures or revision surgery
• Unsatisfactory position or failure of spinal implants
• Failure of fusion
• Excessive bleeding or excessive blood clot formation
• Formation of blood clot within a major vein (Deep Vein Thrombosis or DVT)
• Major blood vessel injury
• Blood clot on the spinal cord (Spinal epidural haematoma)
• Paralysis from spinal cord reperfusion effect – this is an uncommon complication that causes a stroke-like effect in the spinal cord.