Tuberculosis of the Spine
Literature has shown studies that aim to determine the timing and reasons for surgery in spinal tuberculosis and to evaluate the efficacy of different surgical approaches in addressing kyphosis and neural outcomes. In instances of spinal tuberculosis, surgery is advised to tackle the difficulties in diagnosis, the neurological effects, and to halt the advancement of kyphosis.
The spinal cord can tolerate a canal’s encroachment of up to 76% in a typical neurologic condition since it can endure compression that increases gradually.
Nonoperative therapy has shown positive results in patients who have edema/myelitis with primarily fluid compression on MRI, but whose cord size remains largely intact.
However, individuals with cord edema/myelitis or myelomalacia, as well as extradural compression caused by granulation tissue with minimal fluid component, require early surgical decompression.
Two common procedures for decompression of the spine are extrapleural anterolateral decompression and transthoracic transpleural anterior decompression, with comparable outcomes in the dorsal spine. When post-debridement deficiencies exceed two disc gaps, instrumented stabilization may be necessary to prevent graft-related problems in short-segment illness.
However, even with instrumented stabilization, progression of kyphosis can still occur, especially in long-segment illness, so it is essential to closely monitor the situation. Correcting severe kyphosis after healing requires multiple surgical steps and is a risky procedure. Therefore, prospective studies are necessary to define the surgical approach, stages, issues, and challenges of kyphosis correction in spinal TB.
Spinal TB affects up to 50% of patients with musculoskeletal TB, with the anterior column being affected in 98% of these cases. Between 10% and 47% of spinal TB patients experience neural complications, and many develop varying degrees of kyphotic deformity.
The primary objectives of treating spinal tuberculosis are to eliminate the infection, prevent further worsening of angular deformities, and recover from any neurological deficits. The approach to treating spinal TB has evolved over the past 50 years, thanks to advancements in imaging, surgical techniques, and implants. The focus now is on healing the lesion while minimizing spinal deformity, as opposed to previous approaches that aimed to heal the lesion with residual deformity.
General Treatment of Spinal TB
The objectives of the treatment include verifying the diagnosis, eradicating the lesion through bacterial means, addressing spinal cord compression and its associated effects, and managing spinal deformity and its potential consequences, such as the onset of paraplegia in later stages.
Clinical and radiographic examination is a dependable approach for identifying spinal tuberculosis. In situations where the clinical or radiological evidence is not conclusive, a surgical decompression should be performed to obtain adequate tissue for histopathological evaluation and to confirm the diagnosis.
The compromised immunity in numerous HIV-positive individuals and the pathogenic organism’s resistance to therapy have resulted in a renewed outlook on the treatment of spinal TB.
Recent progress in spine reconstruction and instrumentation has provided patients with access to advanced treatment alternatives. Patients with severe neurological deficits were limited to radical resection of the tuberculosis-infected focus and bone grafting as the only available treatment options in the past.
Nevertheless, early diagnosis has become possible with the advent of modern imaging modalities such as CT and MRI. Advanced spinal TB patients in developing nations can now receive nonoperative treatment due to the availability of more powerful antituberculosis therapy regimens.
A patient with TB of the spine who receives non-operative treatment should be regarded as a nonresponder and surgery should be strongly considered if they develop a new lesion or do not exhibit an adequate clinical radiographic healing response.
When a patient with a deep-seated vertebral tubercular lesion should be classified as a nonresponder requires agreement among researchers. The surgery is necessary to make the diagnosis, lessen the disease burden, and obtain enough tissue for culture and sensitivity tests.
If a patient with spinal TB undergoes non-operative treatment but does not show adequate clinical radiographic healing or develops a new lesion, surgery should be strongly considered. However, there is a need for agreement among researchers on when to classify a patient with a deep-seated vertebral tubercular lesion as a nonresponder. Surgery is necessary to diagnose the condition, reduce the disease burden, and collect sufficient tissue for culture and sensitivity tests.
For the past 50 years, two surgical treatment strategies for spinal TB have been used: universal extirpation surgery and limited surgery with specific indications. Current antitubercular medications have made it possible to sterilize the lesion, eliminating the need for universal surgery.
A study by the British Medical Research Council found that both the Hong Kong procedure (anterior radical resection and débridement with fusion) and nonoperative treatment produced positive outcomes, but developing nations lack the resources for fusion surgery. Patients with a higher number of affected vertebrae may experience some kyphosis before the lesion heals, and before brace support is needed.
Spinal instability occurs when both columns of the spine are compromised, such as in spinal trauma or vertebral fractures. Chronic inflammation like that caused by tuberculosis may not necessarily make the spine unstable due to the healing response of the tissues. However, if an infection process and a mechanical insult occur together, the spine can become unstable.
When tuberculosis damages the facets and posterior complexes, the spine becomes unstable, resulting in a neurological deficit. These lesions should be recognized on AP radiographs, and if imaging shows destruction of both columns of the vertebral bodies, the spine should be stabilized. Patients with significant kyphosis or long-segment disease may also require stabilization.
Neurologic complications in the spine can be caused by cord compression, instability, intrinsic factors, and infective thrombosis/endarteritis. Pus, granulation tissue, caseous tissue, discs, or bony sequestra can compress the spinal cord, but there may not always be a correlation between cord compression and neural deficits.
Instability can be caused by pathological subluxation or dislocation due to pan vertebral illness. Intrinsic factors such as cord edema, myelomalacia, and direct affectation of the meninges and spinal cord can also lead to neural complications. Infectious thrombosis or endarteritis can also cause neural complications, but a combination of factors may result in less severe canal compromise and neural complications.
Our Goal at Complete Orthopedics
Spinal TB can cause devastating effects such as paralysis and deformity, and its prevalence is increasing worldwide, especially among immunocompromised individuals. Despite advances in understanding and treatment, the incidence of paraplegia and spinal deformity remains around 20%.
Gross kyphosis can lead to pulmonary and cardiac complications, and while chemotherapy may render the disease inactive, vertebral collapse can persist until the bone matures into a bone block indicating healing. However, significant advancements in TB chemotherapy and spinal canal decompression have improved outcomes, and with early diagnosis and treatment, excellent results can be achieved.
The goal of treating kyphosis caused by spinal TB is to achieve as close to a normal kyphosis as possible. However, since the dorsal spine naturally has a kyphosis of 10° to 20°, a correction may not always be necessary. Dorsolumbar kyphosis can cause compensatory lumbar lordosis and may only require minor correction.
In a study of 28 cases, a surgical approach involving posterolateral decompression and anterior interbody fusion was used to correct an average kyphosis of 40.2° from a preoperative mean of 64.3°. More research is needed to determine the best surgical approach, steps, stages, and challenges for correcting kyphosis of 60° or more.
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I am Vedant Vaksha, Fellowship trained Spine, Sports and Arthroscopic Surgeon at Complete Orthopedics. I take care of patients with ailments of the neck, back, shoulder, knee, elbow and ankle. I personally approve this content and have written most of it myself.
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