Complications associated with prone positioning in elective spinal surgery

Table 1 Positioning complications and risk factors

Complication	Risk factors
Ophthalmological complications
ION[14]	Obesity, male sex, Wilson frame use, longer anesthetic duration, greater estimated blood loss, increased ratio of crystalloid to colloid
Posterior ION[13]	Blood loss greater than 4 L, persistent relative hypotension
Anterior ION[16]	Atherosclerosis, diabetes
Central retinal artery occlusion[5,13]	External compression of the eye
Cortical blindness[13]	Profound hypotension, prolonged hypoxia, cardiac arrest, thromboembolism
Neurologic complications
Acute cervical myelopathy[20]	Cervical spondylosis, neck extension, paralytic anesthesia
Brachial plexopathy[21]	Extension, external rotation, and abduction of the arm, ipsilateral rotation and lateral flexion of neck, shoulder braces
Ulnar nerve palsy[30]	Obesity, inadequate elbow padding
Myocutaneous complications
Compartment syndrome[34-36]	Padding directly over the compartment, obesity
Pressure ulcers[37,38]	Procedure duration, advanced age, obesity, steroid administration
Femoral head avascular necrosis[42]	Pressure over the groin, hypotension

ION: Ischemic optic neuropathy.