Tuberculosis Spondylitis (TB spine/Pott’s diseasis) By Dr Phillipo Leo Chalya

1. Introduction Tuberculous spondylitis has been documented in ancient mummies from Egypt and Peru It is one of the oldest demonstrated diseases of humankind. Percival Pott presented the classic description of TB spine in 1779.

Introduction (cont.) Since the advent of antiTB drugs and improved public health measures, TB spine has become rare in industrialized countries. However it is still a common diseasis in developing countries.

Introduction (cont.) TB spine causes serious morbidity, including permanent neurologic deficits and severe deformity. Medical treatment or combined medical and surgical strategies can control the disease in most patients

2. Epidemiology TB spine is common in developing countries> developed countries Internationally approx. 1-2% of total TB cases are attributable to Pott disease. As with other forms of TB, the frequency is related to socioeconomic factors and historical exposure to the infection.

Epidemiology (cont.) Sex: Males are more often affected (1.5-2:1). Age: In developed countries Pott dx primarily occurs in adults. In countries with higher rates of infection, it mainly occurs in children

Epidemiology (cont.) Mortality/Morbidity : Pott disease is the most dangerous form of musculoskeletal TB. It can cause bone destruction, deformity, and paraplegia It commonly involves the thoracic and lumbosacral spine.

4. Pathophysiology Pott disease is usually secondary to an extraspinal source of infection. The basic lesion is a combination of osteomyelitis and arthritis. Typically, more than one vertebra is involved.

Pathophysiology (cont.) The area usually affected is the anterior aspect of the vertebral body adjacent to the subchondral plate Tuberculosis may spread from that area to adjacent intervertebral disks. In adults, disk disease is secondary to the spread of infection from the vertebral body.

Pathophysiology (cont.) In children, because the disk is vascularized, it can be a primary site. Progressive bone destruction leads to vertebral collapse and kyphosis. The spinal canal can be narrowed by abscesses, granulation tissue, or direct dural invasion

Pathophysiology (cont.) This leads to spinal cord compression and neurologic deficits. Kyphotic deformity occurs as a consequence of collapse in the anterior spine. Lesions in the thoracic spine have a greater tendency for kyphosis than those in the lumbar spine.

Pathophysiology (cont.) A cold abscess can occur if the infection extends to adjacent ligaments and soft tissues. Abscesses in the lumbar region may descend down the sheath of the psoas to the femoral trigone region and eventually erode into the skin.

5. Clinical presentation Presentation depends on the following: Stage of disease Site Presence of complications such as neurologic deficits, abscesses, or sinus tracts. The reported average duration of symptoms at the time of diagnosis is 3-4 months.

Clinical presentation (cont.) The average duration of symptoms at the time of diagnosis is 3-4 months Back pain is the earliest and most common symptom. Patients have usually had back pain for weeks prior to presentation. Pain can be spinal or radicular.

Clinical presentation (cont.) Constitutional symptoms include fever and weight loss. Neurologic abnormalities occur in 50% of cases and can include spinal cord compression with paraplegia, paresis, impaired sensation, nerve root pain, or cauda equina syndrome.

Clinical presentation (cont.) Cervical spine tuberculosis is a less common presentation but is potentially more serious because severe neurologic complications are more likely. This condition is characterized by pain and stiffness. Patients with lower cervical spine disease can present with dysphagia or stridor. Symptoms can also include torticollis, hoarseness, and neurologic deficits.

Clinical presentation (cont.) The clinical presentation of TB in HIV patients is similar to that of HIV negative patients; however, the relative proportion of individuals who are HIV positive seems to be higher.

Clinical presentation (cont.) Physical examination should include the following: Careful assessment of spinal alignment Inspection of skin, with attention to detection of sinuses Abdominal evaluation for subcutaneous flank mass Meticulous neurologic examination

Clinical presentation (cont.) The thoracic spine is frequently reported as the most common site of involvement followed by lumber spine The remaining cases correspond to the cervical spine. Spine deformity (kyphosis) of some degree occurs in almost every patient.

Clinical presentation (cont.) There may be large cold abscesses of paraspinal tissues or psoas muscle that protrude under the inguinal ligament. They may erode into the perineum or gluteal area.

Clinical presentation (cont.) Neurologic deficits may occur early in the course of disease. Signs depend on the level of spinal cord or nerve root compression

Clinical presentation (cont.) Disease involving the upper cervical spine can cause rapidly progressive symptoms. Retropharyngeal abscesses occur in almost all cases. Neurologic manifestations occur early and range from a single nerve palsy to hemiparesis or quadriplegia

Clinical presentation (cont.) If there is no evidence of extraspinal tuberculosis, diagnosis can be difficult. Information from imaging studies, microbiology, and anatomic pathology should help establish the diagnosis

6.Workup 6:1 Lab studies Tuberculin skin test demonstrates a positive finding in 84-95% of patients who are non–HIV-positive. ESR may be markedly elevated (>100 mm/h).

Workup (cont.) Microbiology studies to confirm diagnosis: Obtain bone tissue or abscess samples to stain for acid-fast bacilli (AFB), and isolate organisms for culture and susceptibility. These study findings may be positive in only about 50% of the cases.

Workup (cont.) 6:2 Imaging studies Plain radiography demonstrates the following characteristic changes of spinal tuberculosis: Lytic destruction of anterior portion of vertebral body Increased anterior wedging

Workup (cont.) Additional findings Collapse of vertebral body Reactive sclerosis on a progressive lytic process Enlarged psoas shadow with or without calcification Additional findings Vertebral end plates are osteoporotic. Intervertebral disks may be shrunk or destroyed.

Workup (cont.) Fusiform paravertebral shadows suggest abscess formation. Bone lesions may occur at more than one level.

Workup (cont.) Intervertebral disks may be shrunk or destroyed. Vertebral bodies show variable degrees of destruction

Workup (cont.) CT scanning CT scanning provides much better bony detail of irregular lytic lesions, sclerosis, disk collapse, and disruption of bone circumference. Low-contrast resolution provides a better soft tissue assessment, particularly in epidural and paraspinal areas.

Workup (cont.) It detects early lesions and is more effective for defining the shape and calcification of soft tissue abscesses. In contrast to pyogenic disease, calcification is common in tuberculous lesions

Workup (cont.) MRI MRI is the criterion standard for evaluating disk space infection and osteomyelitis of the spine and is most effective for demonstrating the extension of disease into soft tissues and the spread of tuberculous debris under the anterior and posterior longitudinal ligaments

Workup (cont.) Procedures: MRI is most effective for demonstrating neural compression. In developed countries, MRI has nearly replaced CT myelography. Procedures: Some patients are diagnosed following an open drainage procedure (eg, following presentation with acute neurologic deterioration).

Workup (cont.) Histologic Findings: Since microbiologic studies may be nondiagnostic, anatomic pathology can be very significant. Gross pathologic findings include exudative granulation tissue with interspersed abscesses. Coalescence of abscesses results in areas of caseating necrosis.

7. Treatment 7:1 Medical treatment Medical therapy requires combination regimens with at least 3 antituberculous drugs. A 3-drug regimen usually includes INH, rifampin, and pyrazinamide. The duration of treatment ranges from 9-12 months

Treatment (cont.) 7:2 Surgical treatment Indications Neurologic deficit (acute neurologic deterioration, paraparesis, paraplegia) Spinal deformity with instability No response to medical therapy

Treatment (cont.) Resources and experience are key factors in the decision to use a surgical approach The most appropriate method of reconstruction depends on the level of vertebral spine involved and the extent of bony destruction.

Treatment (cont.) The lesion site, extent of vertebral destruction, and presence of cord compression or spinal deformity determine the specific operative approach.

Treatment (cont.) In disease involving the cervical spine, the following factors justify early surgical intervention: High incidence and severity of neurologic deficits Severe abscess compression that may induce dysphagia or asphyxia Instability of the cervical spine

Treatment (cont.) Contraindications Vertebral collapse of a lesser magnitude is not considered an indication for surgery because with appropriate treatment and therapy compliance, it is less likely to progress to severe deformity. Vertebral damage is considered significant if more than 50% of the vertebral body is collapsed or destroyed or if there is spinal deformity of more than 5°.