Answer: All of the above
Loss of vision is a rare complication following spinal fusion surgery, with incidence reported between 0.017 to 0.1%. All surgical procedures on the spine are usually performed in the prone position, which can put the eyes at risk for injury if excessive pressure is placed on the periorbital area for a prolonged period of time. This risk is magnified by the fact that in the prone position, direct visualization of the patient’s eyes, nose, and mouth by the anesthesiologist and the surgeon is more difficult. (Reference: Patil et al.)
Chen L, Yang J, Zhang Y, Liu Y. Combined fascia iliaca and sciatic nerve block for hip surgery in the presence of severe ankylosing spondylitis: a case-based literature review. Reg Anesth Pain Med. 2016 Jan 5. [Epub ahead of print]
De Rojas JO, Syre P, Welch WC. Regional anesthesia versus general anesthesia for surgery on the lumbar spine: a review of the modern literature. Clin Neurol Neurosurg. 2014;119:39-43.
Deyo RA, Mirza SK, Martin BI, et al. Trends, major medical complications, and charges associated with surgery for lumbar spinal stenosis in older adults. JAMA. 2010;303:1259-1265.
Edgcombe H, Carter K, Yarrow S. Anaesthesia in the prone position. Br J Anaesth. 2008;100:165-183.
Eipe N, Fossey S, Kingwell SP. Airway management in cervical spine ankylosing spondylitis: Between a rock and a hard place. Indian J Anaesth. 2013;57(6):592-595. doi: 10.4103/0019-5049.123333.
Fleisher LA, Fleischmann KE, Auerbach AD, et al. 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery: a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines. J Am Coll Cardiol. 2014;64:e77-e137.
Goodman SM, Figgie M. Lower extremity arthroplasty in patients with inflammatory arthritis: preoperative and perioperative management. J Am Acad Orthop Surg. 2013 Jun;21(6):355-63. doi: 10.5435/JAAOS-21-06-355.
Patil CG, Lad EM, Lad SP, et al. Visual loss after spine surgery: a population-based study. Spine (Phila Pa 1976) 2008; 33:1491.
Postoperative Visual Loss Study Group. Risk factors associated with ischemic optic neuropathy after spinal fusion surgery. Anesthesiology. 2012;116:15-24.
Putnis SE, Wartemberg GK, Khan WS, Agarwal S. Literature review of total hip arthroplasty in patients with ankylosing spondylitis: perioperative considerations and outcome. Open Orthop J. 2015;9:483-8. doi: 10.2174/1874325001509010483.
Schnaser EA, Browne JA, Padgett DE, Figgie MP, D’Apuzzo MR. Perioperative complications in patients with inflammatory arthropathy undergoing total knee arthroplasty. J Arthroplasty. 2015;30(9 Suppl):76-80. doi: 10.1016/j.arth.2014.12.040.
Sciubba DM, Nelson C, Hsieh P, et al. Perioperative challenges in the surgical management of ankylosing spondylitis. Neurosurg Focus. 2008;24(1):E10. doi: 10.3171/FOC/2008/24/1/E10.