Spinal infections affect the spine and the spinal cord (in a small subgroup). Tuberculosis (commonly referred as Pott's spine) is the most common type of infection affecting the spine. This is the most common form of extra-pulmonary tuberculosis. It causes significant disability, loss of work, long term spinal deformity and neurological morbidity.
Delay in diagnosis and inappropriate and inadequate treatment is the most common cause of poor outcomes. Back pain is the most common symptom of this condition. Back pain not relieving with routine measures, night pains, persistent pain for more than few weeks should raise the suspicion of tuberculosis.
MRI is the investigation of choice. Contrast enhanced MRI helps to identify small areas of infection that may not be visible on non-contrast MRI scans.
In majority of patients (about 80-90%), conservative ambulatory anti-tubercular therapy for period of 9-12 months is adequate and curative. The treatment duration is longer than that for pulmonary tuberculosis. In addition, alternate day treatment is not recommended. Serial X-rays and MRI scans are required to assess the response and duration of treatment.
Biopsy is not required in all patients. In majority, the radiological picture is quite characteristic and diagnostic. Biopsy is needed in those with atypical radiology. Biopsy can be done using USG or CT guidance as an outpatient procedure. The pus / tissue is sent for histological and microbiological analysis including GenXpert for PCR analysis to detect tubercle bacilli in these patients as the bacterial load is low and can be missed on AFB staining. It also tests the resistance to first line drugs as Rifampicin and Isoniazid.
Surgical intervention is required in the following situations:
1. Neurological deficits
2. Persistent pain inspite of medical treatment for at least 6 weeks.
3. Significant spinal deformity due to vertebral body destruction.
The entire spine can be affected with tuberculosis starting from Craniovertebral junction to lumbo-sacral spine. The surgical methods depend upon the site and extent of involvement. While conventional surgical methods remain the mainstay of the treatment, minimally invasive methods are also being used i select subgroup of patients. Dr Nitin Garg has a personal experience of using minimally invasive methods for treating tuberculosis of the dorsal and lumbar spine (see publications).
Minimally invasive methods have the benefit of minimal surgical morbidity, faster recovery, and better tolerance in patients whose general physical condition is already compromised.
Other infections include fungal, bacterial, and rare infections as salmonella. These are diagnosed on biopsy and histopathological and microbiological analysis. Management is medical and surgical in few indications as outlined above.