INTRODUCTION

Spinal tuberculosis (TB) is seen in 2% of TB patients and 50% of skeletal involvement of TB⁽¹⁾. Approximately 90% of the patients are affected by the lower thoracic and upper lumbar vertebrae⁽²⁾. Spinal TB can lead to the destruction of the vertebral body, posterior elements and pars interarticularis, which can lead to deformity, spondylolisthesis, and even paraplegia⁽³⁾. Although clinical examination, patient history and radiography are usually sufficient for diagnosis, early computer tomography and magnetic resonance imaging (MRI) are useful^(4,5). Usually, only anti-TB drugs are used in the treatment but surgery may be necessary if signs of spinal compression and neurological deficits, instability, advanced kyphosis deformity or drug resistance occur⁽⁶⁾. Debridement, grafting and internal fixation are the main objectives of surgery. Surgical timing, amount of debridement and surgical approach are still controversial^(7). The purpose of this review is to provide information about the current approaches in the diagnosis and treatment of spinal TB.

Diagnosis

Diagnosis is difficult in the initial stages, delay in diagnosis may lead to serious spinal cord injuries⁽⁸⁾. Predisposing factors include malnutrition, alcoholism, diabetes, and human immunodeficiency virus (HIV) infection⁽⁹⁾. Symptoms are usually insidious, there may be complaints that have been going on for years before diagnosis⁽¹⁾. Low back pain, fever, weight loss, and night sweats are the most common symptoms⁽¹⁰⁾. The diagnosis usually can be made on the basis of predisposing factors, history of TB disease, clinical findings and imaging methods⁽¹⁾. However, the gold standard in diagnosis is positive Mycobacterium tuberculosis tissue culture⁽¹¹⁾. Because of this, in the case of clinical suspicion, tissue culture should be performed. In addition, performing polymerase chain reaction in samples taken with biopsy, erythrocyte sedimentation rate (ESR), immunological hematological tests and skin test are helpful in diagnosis⁽¹²⁾. Radiography is preferred as the initial imaging method and the “bird’s nest” appearance can be seen, evocative of an aortic aneurysmal phenomenon reflected from aortic pulsations⁽⁸⁾. Computed tomography (CT) can provide information on the extent of vertebral involvement. Abscess and intra-canal compression can be seen in the CT taken with intrathecal contrast⁽¹³⁾. The preferred imaging method for spinal cord TB is MRI. Typical findings include lesions in the vertebral end plates, anterior involvement in the vertebral body, subligamentous spreading, paraspinal cold (without signs of severe acute inflammation) abscesses and calcifications, vertebral bodies, vertebral body destruction and collapse but the disc is usually protected⁽⁸⁾. MRI findings can also be used in treatment follow-up, but pain reduction and neurological recovery are more important in follow-up treatment⁽¹⁴⁾. Javed et al.⁽¹⁵⁾ compared the clinical and laboratory findings of patients with spinal epidural tumors and patients with spinal TB. They reported pain, fever, progressive lower extremity weakness, high ESR, epidural and paravertebral contrast involvement, spinal deformity and adjacent level involvement in MRI as possible diagnostic criteria for the spinal tuberculosis. In distinguishing pyogenic spinal infections, laboratory findings and imaging methods are useful. It has been reported that positron emission tomography, the use of which has increased in recent years, can be used in diagnosis and follow-up in pott disease⁽¹⁶⁾.

Interferon gamma release tests used in the diagnosis of latent tuberculosis infection are not reliable in the diagnosis of spinal TB⁽¹⁷⁾. More clinical trials investigating different antigens are needed in this regard. In addition, although the low sensitivity of nucleic acid amplification methods prevents excluding the diagnosis, it is useful to confirm the diagnosis⁽¹⁸⁾.

Biopsy can be attempted from the suspicious lesion by interventional diagnostic methods or endoscopic methods, but false negative results may be seen in these diagnostic methods⁽¹⁴⁾. Therefore, in the presence of clinical symptoms, the negative interventional diagnostic methods should not prevent open biopsy from being made⁽¹⁹⁾.

Classification

Based on the clinicopathological correlation, anterior spinal tuberculosis is divided into five stages⁽²⁰⁾ (Table 1). The stages of anterior spinal tuberculosis differ from their degree of paraplegia. Stages of anterior spinal tuberculosis show bone involvement and degree of deformity while paraplegia degrees indicate the severity of spinal cord compression. Several classifications have been developed for paraplegia grading due to spinal tuberculosis. These were developed to determine the degree of pressure in the spinal cord and to evaluate the severity of the disease in making the surgical decision^(21,22). The most common of these is the classification developed by Kumar⁽²²⁾ based on the patient’s weakness complaints, walking ability and neurological examination findings (Table 2). There are also classifications that define the paraplegia that occurs within 2 years from the onset of the disease as early onset and the result of active disease, the paraplegia that occurs after 2 years as late onset and the result of sequelae of the disease⁽²³⁾. In both anterior and posterior spinal tuberculosis, motor nerves are affected before the sensory nerves^(23,24). Sensory and autonomic loss of function are added as compression increases.

Treatment

The aim of the treatment is to confirm the diagnosis, to clear the lesion from the bacteria, and to eliminate spinal deformity and spinal cord pressure. Rifampicin, isoniazid (INH), pyrazinamide and ethambutol form the basis of drug therapy as anti-TB drugs. British Medical Research Council⁽²⁵⁾ recommends combination chemotherapy for 6-9 months in the treatment of tuberculous spondylitis of the thoracolumbar spine. However, the work of this council does not include patients with vertebral involvement, cervical lesions, or patients with major neurological involvement. For this reason, many experts still recommend treatment for 9-12 months.

HIV increases the reactivation of the disease, the risk of more atypical and severe course. Studies on spinal tuberculosis and HIV show that good clinical outcomes can occur, regardless of HIV activation status and the presence of antiretroviral therapy⁽²⁶⁾.

Treatment of spinal tuberculosis with multidrug-resistant microorganism (resistant to INH and rifampicin) or extensively drug-resistant microorganism [(resistant to a quinolone and a parenteral drug (amikacin, kanamycin or capreomycin) with INH and rifampicin)] should continue in specialized centers experienced in management.

In the literature, controversy continues regarding the need for additional surgical intervention in the treatment of spinal TB. Jutte and Van Loenhout-Rooyackers⁽²⁷⁾, in their review with randomized controlled trials, compared spinal tuberculosis cases treated with chemotherapy only with those who received surgical treatment in addition to chemotherapy. In this study, deterioration in kyphosis angle, neurological deficit, bone fusion, recovery from disease and activity recovery rates at baseline or follow-up were evaluated, but no significant difference was found between these two groups in terms of these results. Nevertheless, many authors have proposed surgery in the presence of progressive neurological deficit, instability, progressive kyphosis above 50 degrees or disease unresponsive to drug treatment.

In surgery, after debridement, the correction of deformity for decompression and instrumentation can be performed for stabilization. It has been reported that grafting is effective for providing spinal fusion⁽²⁸⁾. Emergency decompression surgery is indicated only in patients with acute spinal cord compression findings⁽²⁹⁾.

In some patient groups, there are also studies reporting that only instrumentation can be beneficial without radical debridement. Qian et al.⁽⁷⁾, in the study on 74 patients with Frankel et al.⁽³⁰⁾ grading scores of D and E, compared the group with radical debridement, grafting and anterior instrumentation and group with posterior instrumentation only. In terms of operation time, blood loss, and 3^rd and 6^th month ESR, they found that only posterior instrumentation group had significantly better results, but could not find a significant difference in terms of kyphosis angles or fusion rates.

The surgical approach in spinal tuberculosis surgery is still under discussion. Although the anterior approach provides a larger surgical site and direct access to the lesion, it may create instability after decompression⁽³¹⁾. In addition, the use of the posterior approach increases due to the risk of vascular nerve damage, increased blood loss, prolonged operation time and length of hospital stay with the anterior approach^(32,33). However, when deciding on the approach, the region of the lesion, instability, patient-related factors and severity of deformity should be taken into account. In spinal tuberculosis with wide anterior destruction, where anterior stability is lost, only the posterior approach may result in poor decompression, poor correction and implant failure⁽³⁴⁾.

Spinal TB surgery should be performed by experienced surgeons in experienced centers. Among the effective techniques, choosing the technique that is the safest and well known by the surgeon will reduce the complication rates. Moon et. al.⁽³⁵⁾, in their study on 901 patients who underwent spinal tuberculosis surgery, reported increasing of the corrected kyphosis angle (32%) and graft failure (14%) as the most common complications associated with the disease. In the same study, thoracic cavity complications (43%), thrombophlebitis (26%) and sympatheticolysis symptoms (32%) were reported as surgical complications, especially in the anterior approach.

CONCLUSION

As a result, spinal tuberculosis is still an important disease and should be considered in differential diagnosis in patients with chronic low back pain and neurological symptoms. Imaging tests such as MRI and CT can help to diagnose the disease, but microbiological diagnosis is also required to confirm the diagnosis. Although the main treatment is drug therapy, it is useful to add surgical treatment in case of advanced deformity and paraplegia.

Authorship Contributions

Surgical and Medical Practices: A.M.Ö., M.I.T., Concept: M.I.T., A.M.Ö., Design: M.I.T., AM.Ö., Data Collection or Processing: M.I.T., AM.Ö., C.Y., Analysis or Interpretation: M.I.T., AM.Ö., C.Y., Literature Search: C.Y., M.I.T., A.M.Ö., Writing: C.Y., M.I.T., A.M.Ö.

Conflict of Interest: There are no conflicts of interest in connection with this paper, and the material described is not under publication or consideration for publication elsewhere.

Financial Disclosure: The authors declared that there is no financial relationship with this paper.