MSK-16 · Spine: Red Flags, Cauda Equina, Scoliosis, and Ankylosing Spondylitis

Spine: Red Flags, Cauda Equina, Scoliosis, and Ankylosing Spondylitis. Part of the Musculoskeletal series of the Reflex PM&R Board Review podcast. Audio corrections: (1) In the audio: And a normal, healthy chest expands by more than 5 centimeters. — Correct: Roughly 5 cm or more is the usual normal, but a value just under 5 cm is nonspecific and common in healthy older adults. The tighter, more specific threshold for costovertebral joint involvement in ankylosing spondylitis is expansion of less than 2.5 cm at the fourth intercostal space or xiphisternum. (2) In the audio: For curves under 25 degrees, the standard of care is observation. — Correct: Board references draw the observation-to-bracing line at 20 degrees, and the BrAIST trial enrolled 20- to 40-degree curves. Many clinical protocols wait for 25 degrees or documented progression, so treat 20 to 25 degrees as the boundary rather than 25 alone. (3) In the audio: Over 40 to 50 degrees is the standard threshold where you indicate the patient for operative intervention — Correct: The surgical threshold splits by skeletal maturity: greater than 40 degrees in a skeletally immature patient, greater than 50 degrees once skeletally mature, greater than 35 degrees (or any decline in pulmonary function) in neuromuscular scoliosis, and relentless progression at any magnitude. (4) In the audio: rather than destroying the annulus fibrosus like an inflammatory syndesmophyte does — Correct: Both DISH and ankylosing spondylitis characteristically preserve intervertebral disc height. The discriminator is the bridging bone: thick flowing non-marginal ossification of the anterior longitudinal ligament in DISH versus thin vertical syndesmophytes arising from the annulus margins in ankylosing spondylitis. Preserved discs separate DISH from degenerative spondylosis, not from ankylosing spondylitis. (5) In the audio: you must actively suspect hematogenous seeding of Staph aureus into the spine — Correct: Correct as far as it goes: S. aureus is the leading organism in native vertebral osteomyelitis, including in people who inject drugs. The audio omits that Pseudomonas aeruginosa and other gram-negative organisms are disproportionately more frequent in this population, which is why empiric coverage is broadened while cultures are pending. The written chapter is correct. Full correction register: https://www.reflexpmr.com/errata. The full companion chapter and a linked board-style Q-bank set for this topic are at https://www.reflexpmr.com/read/MSK-16.