SPINAL TUBERCULOSIS, A DUTCH PERSPECTIVE: SPECIAL REFERENCE TO SURGERY

Abstract

The main goal is to provide insight into spinal tuberculosis from a Dutch perspective: to establish the size of the problem in the Netherlands, analyse the reasons for misdiagnosis, assess optimal treatment, verify if this is truly optimal, establish the effect of surgery, and find out when surgery is needed.

We made an analysis of the increase in Bone and Joint Tuberculosis (BJTB) in the Netherlands during the recent years. Between 1993 and 2000 a total of 532 cases of BJTB were found. Univariate analysis showed that the increase in incidence was restricted to non-Dutch people from endemic areas. It is important to note that only 15% of BJTB patients in our series also suffered from pulmonary TB. In our study a lengthy delay by both patients and doctors was found for BJTB (mean period 32 weeks), probably explained by a low index of suspicion and declining expertise.

We report a previously undescribed misdiagnosis and subsequent mistreatment with radiation for tuberculosis of the spine in two patients.

Both patients were misdiagnosed as having malignancies, without sufficient material for histological and culture examination. Both received radiotherapy, both experienced growth of the lesion, and in one of the patients the neurological deficit increased and did not reverse after initiation of the proper TB treatment. The main reasons for misdiagnosis of spinal TB are low incidence, low index of suspicion, declined expertise, and accepted failed biopsy. Radiotherapy locally aggravates tuberculous spinal lesions.

There is no uniform advice in the literature regarding the duration of chemotherapeutic treatment for spinal tuberculosis. A review of the literature from 1978 (after the introduction of Pyrazinamide) to 2000 was performed.

The relapse rate of 2% for the patients that had > 6 months chemotherapy is low, as is the relapse rate of 0% for patients with 6 months treatment. We concluded that the duration of chemotherapy for spinal tuberculosis can be 6 months.

Subtherapeutic concentrations intralesional may result in selection of a resistant bacterial population and lead to treatment failure.

Intralesional drug concentrations were below Minimal Inhibitory Concentration (MIC) values in 0/15 patients for ISO, 2/13 for RIF, and 8/9 for PYR. In 5/8 patients receiving all three drugs both RIF and PYR had Cmax:MIC ratios < 4, indicating intralesional subtherapeutic drug levels.

Drainage is advised as additional therapy for patients with pleural effusion or psoas abscesses; it reduces the intralesional bacterial load and shortens the time of resolution of the lesions.

A Cochrane systematic review was performed with the aim to compare chemotherapy to chemotherapy plus surgery in the treatment of spinal TB.

There were no statistically significant differences between the treatment and control group for kyphosis and bony fusion. There were no significant differences in neurology, but some patients from the control group had an operation (change of allocated treatment) for persisting deficit. Chemotherapy is the critical factor in the management of tuberculosis of the spine. Routine surgery is not indicated. Surgery has a role in subgroups of patients for orthopaedic or neurological reasons: large or progressive kyphosis, and progressive or persistent neurological deficit.

We evaluated radiographic and clinical parameters as early predictors for the final kyphosis angle in spinal TB to identify the patients at risk for developing severe or progressive kyphosis.

Univariate analysis revealed no significant independent predictors. Multivariate analysis showed that bone loss < 0.3 in combination with a thoracic localisation indicated 97% chance of favourable outcome. A simple and clinically useful algorithm for early prediction of kyphosis in spinal TB is presented.