Ankylosing spondylitis: Epidural risks

Ankylosing spondylitis is a chronic inflammatory disease (mostly in males, associated with uveitis and vasculitis / aortic insufficiency) and leading to ossification of the axial ligaments, SI joints, and subsequent fusion of the axial skeleton. These patients are challenging regardless of the anesthesia technique chosen – general anesthesia is complicated by difficulties with airway management (reduced cervical spine and temporomandibular mobility) as well as near-universal mandate for controlled mechanical ventilation (decreased thoracic compliance, pulmonary fibrosis, restrictive lung disease).

Neuraxial anesthesia is complicated by ossification of spinal ligaments and reduced intervertebral spaces – caudal anesthesia may be a reasonable alternative.

Ankylosing Spondylitis

• Systemic Considerations: uveitis, vasculitis, aortic insufficiency, pulmonary fibrosis, restrictive lung disease
• General Anesthesia: reduced cervical and TMJ mobility
• Regional Anesthesia: osseous ligaments, reduced intravertebral spaces (consider caudal)

Epidurals are more difficult to place in patients with AS due to increased ossification of the spine. The major concern is the higher incidence of epidural hematoma in this AS versus the general population. This is attributed to multiple traumatic attempts and higher incidence of NSAID use among patietns. There as been at least two case reports of total spinal anesthesia from epidural test dose even after negative aspiration. The authors believed that they had had inadvertent catheter migration into the subdural space or seepage of local anesthetic through perforations in the dura created by multiple attempts.