summary Spinal tuberculosis, also known as Pott's disease, is a spinal infection caused by Mycobacterium tuberculosis that can lead to osteomyelitis, kyphotic deformity, and mechanical instability Diagnosis is made with a CT-guided biopsy evaluated for acid-fast bacilli Treatment is usually bracing and anti-tuberculosis antibiotics in the absence of neurological defects or mechanical instability. Surgical management is indicated in the presence of neurological deficits, progressive kyphosis, and/or mechanical instability Epidemiology Incidence increasing incidence in the U.S. due to a growing immunocompromised population Demographics HIV-positive (often seen in patients with CD4+ counts of 50-200) Anatomic location 15% of patients with TB will have extrapulmonary involvement the spine, and specifically the thoracic spine, is the most common extrapulmonary site 5% of all TB patients have spine involvement Etiology Pathoanatomy early infection begins in the metaphysis of the vertebral body spreads beneath the anterior longitudinal ligament, leading to login to view 4 more bullets initially does not involve the disc space (distinguishing it from pyogenic osteomyelitis, but can be misdiagnosed as a neoplastic lesion) chronic infection severe kyphosis login to view 13 more bullets Presentation Symptoms onset of symptoms is typically more insidious than that of pyogenic infections constitutional symptoms login to view 4 more bullets back pain login to view 1 more bullet Physical exam kyphotic deformity neurologic deficits (present in 10-47% of patients with Pott's disease) mechanisms login to view 4 more bullets Imaging CXR 66% will have an abnormal CXR indicated for any patient in whom TB is a possibility Spine radiographs early infection involvement of the anterior vertebral body with sparing of the disc space (this can differentiate TB from a pyogenic infection) late infection lucency and compression of adjacent vertebral bodies, disc space destruction, and development of severe kyphosis risk factors for buckling collapse ("spine-at-risk signs") retropulsion subluxation lateral translation toppling MRI with gadolinium contrast indications preferred imaging study for diagnosis and treatment planning diagnosis of adjacent levels login to view 1 more bullet findings low signal on T1-weighted images, bright signal on T2-weighted images presence of a septated prevertebral, paravertebral, and/or intraosseous, smooth-walled abscess with a subligamentous extension and breaching of the epidural space endplate disruption login to view 1 more bullet paravertebral soft tissue shadow login to view 1 more bullet high signal intensity of the disc on the T2-weighted image login to view 1 more bullet spinal cord login to view 4 more bullets CT indications demonstrates lesions <1.5 cm better than radiographs inaccurate for detailing epidural extension findings types of destruction login to view 4 more bullets Nuclear medicine studies obtain with a combination of technetium and gallium shown to have the highest sensitivity for detecting infection Studies CBC relative lymphocytosis low hemoglobin ESR usually elevated, but may be normal in up to 25% PPD (purified protein derivative of tuberculin) positive in ~80% Diagnosis CT-guided biopsy with cultures and staining is effective at obtaining a diagnosis should be tested for acid-fast bacilli (AFB) login to view 1 more bullet PCR allows for faster identification (95% sensitivity and 93% accuracy) smear positive in 52% culture positive in 83% Differential Other etiologies of granulomatous infection may have a clinical picture similar to TB atypical bacteria Actinomyces israelii Nocardia asteroides Brucella fungi Coccidioides immitis Blastomyces dermatitidis Cryptococcus neoformans Aspergillosis spirochetes Treponema pallidum Treatment Nonoperative pharmacologic treatment ± spinal orthosis indications login to view 2 more bullets pharmacologic login to view 4 more bullets spinal orthosis login to view 2 more bullets Operative anterior decompression/corpectomy, strut grafting ± posterior instrumented stabilization ± posterior column shortening indications login to view 16 more bullets advantages of surgical treatment login to view 4 more bullets technical aspects login to view 3 more bullets Halo traction, anterior decompression, bone grafting, and anterior plating indications login to view 1 more bullet Pedicle subtraction osteotomy indications login to view 1 more bullet Direct decompression/internal kyphectomy indications login to view 2 more bullets Technique Anterior decompression/corpectomy, strut grafting ± posterior instrumented stabilization ± posterior column shortening indications (see above) techniques single-stage transpedicular two-stage login to view 2 more bullets single-stage extrapleural anterolateral Complications Deformity (kyphosis/gibbus) highest risk after anterior decompression and grafting alone login to view 1 more bullet lowest risk after both anterior and posterior fusion Retropharyngeal abscess can affect swallowing and cause hoarseness TB arteritis and pseudoaneurysm Respiratory compromise if there is costopelvic impingement Sinus formation Pott's paraplegia spinal cord injury can be caused by an abscess, bony sequestra, or meningomyelitis abscess/bony sequestra have a better prognosis than meningomyelitis Atypical Spinal Tuberculosis definition compressive myelopathy without visible spinal deformity or typical radiological appearance etiology intraspinal granuloma neural arch involvement concentric collapse of the vertebra body sclerotic vertebra with bridging of the vertebral bodies treatment laminectomy indications login to view 2 more bullets decompression and myelotomy indications login to view 1 more bullet