Surgical treatment of tuberculosis of spine: Nepalese experience

Introduction Spinal tuberculosis treatment goal is eradication of the disease, neurological protection, and deformity prevention. Accepted indications for conservative or surgical management of the disease are still lacking. The purpose of this study was to classify disease based on preand post-treatment clinical and radiological criteria to help management. Material and methods Out of 101 patients, retrospectively reviewed between 2007 and 2015, seventy adult patients (44 males, mean age 29 years, range 16-76) were included in the study. Patients were evaluated clinically for pain, deformity and neurological status while radiological evaluation included sagittal deformity, vertebra destruction and number of vertebrae involvement. 60 patients underwent surgery (abscess drainage, 2; anterior radical debridement and fusion, 12; anterior debridement + posterior instrumentation, 26; posterior instrumentation, 20) All patients were given anti-tuberculous treatment for 12 months. Mean follow up period was 44.9 months (range: 6-108 months). Result Pre-treatment pain (Visual analogue score, VAS 0-10, mean 7.52) improved by 0.99 at last follow up. Number of vertebrae involved ranged from 1 to 15 (mean 4.2). 38 patients had obvious clinical deformity with Cobb angle mean 36.6° (range 10°-130°). Deformity was corrected at mean of 17.5° (range: -60° to 90°) at last follow up. There were two ASIA A, eight ASIA B, five ASIA C, four ASIA D and 51 patients with ASIA E neurology at the time of presentation. One patient with ASIA A neurology remained same even after decompression while other patient died on the day of surgery. Out of 8 patients with ASIA B neurology six patients improved to ASIA E, one patient remained same and one patient deteriorated to ASIA A. In ASIA C group, three patients improved to ASIA E. One patient deteriorated to ASIA A. All four patients with ASIA D neurological status improved to ASIA E. And all 51 patients with pre-operative ASIA E status remained same but one deteriorated to ASIA C. Eight patients had deformity progression, two patients had deep vein thrombosis, two patients had superficial wound infection and one patients had recurrent cold abscess. Two patients died due to associated co-morbidities. Based upon the clinical and radiological preand post-operative findings; Uncomplicated spines were managed conservatively or with abscess drainage (USG or CT – guided). Complicated spines were managed with posterior instrumentation and complex spines were managed with anterior / posterior procedure (posterior only approach) Conclusion Based upon the outcome of treatment of spinal tuberculosis, conservative treatment results in healing of the disease process with residual deformity while surgical treatment in selected cases results in early pain alleviation, spinal balance, neurologic protection and eventually early return to work.


Introduction
Tuberculosis (TB) remains the major killer in infectious disease, especially in developing countries where treatments are not sufficiently available.The risk of developing tuberculosis is found to be at least 20 times higher in populations with human immunodeficiency virus (HIV).Globally, there are 9.4 million incidences of tuberculosis and approximately 1.2 million of newly diagnosed tuberculosis patients are associated with HIV in each year 1 .Among these numbers, Africa and South East Asian regions contributed 90% of the cases.Skeletal involvement is found in around 10% of patients with spine, hip and knee as the common spreading sites 2 .
Spinal tuberculosis, also known as Pott's disease of the spine, accounts for 17-39% of spinal infections 1 .This happens when tuberculosis spreads out of the lungs and reaches the spine via the rich vascular supply to the vertebrate.Once Mycobacterium tuberculosis has formed a granuloma and has become necrotic, bone destruction occurs and leads to collapse of the vertebral bodies.The classic radiological features are 1) vertebral body destruction, and collapse, 2) soft tissue abscess, 3) vertebral wedging, 4) kyphosis, and 6) gibbus formation.This characteristic leads to cord compression, spinal deformities, and neurological deficits and hence, it has been described as the most serious form of osteoarticular tuberculosis associated with high morbidity 2,3 .The goals of treatment in tuberculosis of the spine are to 1) eradicate necrotic tissue and large tuberculosis abscesses, 2) prevent neurological deterioration, and 3) prevent deformity 4 .
Though chemotherapy is the cornerstone of treatment of spine tuberculosis, the addition of surgical intervention in selected cases results in the optimum outcome in terms of pain alleviation, neurological protection, spinal alignment and eventually early return to work or other activities.The type of radiological and clinical presentation varies between patients.The accepted indications for conservative or surgical management of the disease are still lacking.The majority of recent literatures reviewing the surgical outcomes of TB have been reported from China and India.This report proposed to share our surgical experiences on spinal tuberculosis in Nepal.

Material and methods
A retrospective review of 101 patients treated between 2007 and 2015 was done.There were 62 males and 39 females consisting of 31 patients in pediatric age group between 0 to 15 years (18 M, 13 F), 58 patients in adult age group between 16 and 60 years (39 M, 19 F) and 12 elderly patients above 60 years (5 M, 7 F).Age ranged from 4 to 76 years with the average being 29 years.
All the patients presenting to the hospital were clinically evaluated for pain, deformity and neurological status.Routine laboratory evaluation included Complete Blood Count (CBC), Erythrocyte Sedimentation Rate (ESR), C -Reactive Protein (CRP), and Hemoglobin levels.Those subjected to surgery were also tested for HIV and HBsAg.Pretreatment ESR was evaluated in all patients.Since there was no homogeneity in post-treatment ESR evaluation, it was not considered in the study.
In the growing spine, the posterior elements continue to grow while there is tethering of the growth anteriorly due to tuberculous posing a risk of progression of deformity.The anterioronly procedure will risk deformity progression.Thus posterior instrumentation and fusion along with anterior debridement and reconstruction are recommended in the pediatric age group.Thus due to the difference in management in the growing spine from the adult spine, 31 patients from the pediatric age group were excluded from the study.So the study group consisted of 70 adult patients with 44 males and 26 females.The age ranged from 16 to 76 years with the average being 29 years.Plain x-rays of the involved segments and MRI of the affected level were routinely performed.In later cases, we started doing screening MRI of the whole spine to rule out non-contiguous or skip lesions, where these features will suggest atypical presentation requiring special attention.
Pain experienced by the patient was evaluated by the visual analogue score.The clinical deformity was evaluated for knuckle, gibbus or kyphus.Deformity of the spine was measured on the plain x-rays according to Cobb's method.In lumbar and cervical region, loss of lumbar and cervical lordosis is added to the measured kyphotic deformity to Average normal lordosis is considered to be around 40° and loss of lumbar lordosis is regarded as lumbar hypokyphosis.Neurological status was evaluated accordingly to ASIA scoring system.MRI was evaluated for the region of involvement, the amount of vertebral destruction, the number of vertebrae involved, contiguity of the involvement, pre-or paravertebral abscesses, epidural abscesses and cord compression.
The spine was considered unstable if vertebral body destruction of more than 50% occurred in a single vertebra or involvement of two or more contiguous vertebrae, kyphotic deformity of more than 20°, or translation of more than 5°.
The decision for treatment was made on the basis of clinical as well as radiological findings.The treatments delivered were conservative in 10 patients (5M, 5F) and surgery in 60 patients (39M and 21F).In the surgical group, abscesses were drained in 2 patients (both males), anterior radical debridement and fusion was done in 12 patients (8M, 4F), anterior debridement and posterior instrumentation was done in 26 patients (15M, 11F) and posterior instrumentation only was performed in 20 patients (14M, 6F).In all patients combined anterior/ posterior procedures were from the posterior-only approach in single stage.
All patients had histopathologically proven tuberculosis.Tissue culture and ZN staining were also done in some patients but it was not consistent in all patients, so was not considered in the study.All patients were given anti-tuberculosis treatment consisting of four drugs (Rifampicin, Isoniazid, Pyrazinamide and Ethambutol) for 3 months as intensive phase and then two drugs (Rifampicin and Isoniazid) for another 9 months as a maintenance therapy.
Postoperative follow-up was done at 6 weeks, 3 months, 6 months, 1 year and subsequently every year.During each follow-up patient was evaluated for pain, deformity and neurological status.Plain x-rays were obtained to assess deformity progression, consolidation of the diseased vertebrae and status of the implants.The follow-up period ranged from 1.5 months to 108 months with the average being 44.9 months.

Results
Most of the patients presented late ranging from 15 days to 4 years with the average being 4.6 months.All patients presented with pain except two patients who presented with deformity of the back and progressive neurological deficits.Both the cases were old healed tuberculosis with severe kyphosis.The pre-treatment visual analogue score (VAS) ranged from 0 to 10 with the average being 7.52, which improved to 0.99 during the last followup indicating reduction in pain with stabilization of the spine.
There were 2 patients with cervical, 1 patient with cervico-dorso-lumbar involvement.Of the 22 patients (15 M, 7 F) who had dorsal spinal tuberculosis, an average of 2.5 numbers of vertebrae was involved resulting in kyphotic deformity of 37.7° on average.Fifteen patients (6 M, 9 F) had dorso-lumbar vertebral involvement with an average 2.6 vertebrae affected resulting in a deformity of 36.6°.And there were 29 patients (20 M, 9 F) with lumbar (n-17), lumbo-sacral (n-10) and Sacral (n-2) involvement with an involvement of 2.4 vertebrae on average causing deformity of 18.6° along the sagittal plane.Two patients had cervical tuberculosis (both male) with the mean of 4.2 vertebral involvements.One male patient had cervical-dorso-lumbosacral lesion involving 15 vertebrae while another male patient had dorso-lumbosacral lesion involving 5 vertebrae.Contiguous involvement of vertebrae was observed in 59 (84.3%) patients while non-contiguous involvement was seen in 11 (15.7%)patients.The number of vertebrae involved ranged from 1 to 15 with the average being 2.6 vertebrae.
Thirty-eight (54.3%) patients (23 M, 15 F) had an obvious clinical deformity of the back during clinical examination in the form of the knuckle, gibbus, kyphus or kypho-scoliosis.32 patients (21 M, 11 F) had no obvious deformity on clinical examination.However, they did have radiological deformity in the form of loss of lumbar or cervical lordosis or exaggeration of thoracic kyphosis.All those patients who did not demonstrate clinical deformity had involvement of lumbar, lumbosacral

Discussion
Treatment of tuberculosis of the spine is debatable and controversies exist regarding efficacy of conservative versus surgical management.In surgical management, there is no general consensus about the best approach.However, there is a general agreement that in addition to eradication of the disease and prevention of neurological deterioration, the correction and prevention of the spinal deformity should also be a primary goal.
A basic literature review was conducted to determine the current approaches and their outcomes.The uncomplicated cases are managed by a trial of conservative treatment for 6 weeks.If the patient responds, then the treatment is continued.If the patient does not show any response, surgery is performed for abscess drainage (open or ultrasound guided), or posterior stabilization only.For complicated cases where there is radiological deformity due to vertebral body destruction of more than 50%, management consists of posterior stabilization, correction of deformity by precontouring the rod and draining the paravertebral abscess.The patient is put on antituberculosis treatment as per our protocol.The complex cases are treated with thorough anterior vertebral body debridement and reconstruction followed by posterior stabilization.Based on our experience, our recommended indications for surgery include: 1) Neurological deficit, 2) radiological deformity, and/or 3) severe pain which prevents patient from performing his / her activities of daily living.

Conclusion
This study describes Nepal experience of surgical management of spinal tuberculosis, and proposes a simple, pragmatic scheme for providing treatment for this population of patients.

Figure 1 :
Figure 1: a, b -Antero-posterior and lateral views of thoracic spine showing no abnormalities.c, d -MRI coronal and axial films showing right paravertebral mass.

Figure 2 :
Figure 2: Same patient from Fig.1.a, b -MRI coronal and axial films 6 weeks after empirical start of anti-tuberculosis therapy showing increase in size of the right sided paravertebral mass.c, d, e -MRI sagittal, coronal and axial films one year after starting anti-tuberculosis treatment.

Figure 3 :
Figure 3: a, b, c, d, e -Plain x-ray and MRI of a 38 years old lady showing involvement of D 12 and L 1 vertebrae along with pre-and para-vertebral abscess.X-rays showing fairly maintained vertebral height with slight assymetrical collapse whereas MRI showed two vertebrae involvement.f, g -Immediate and one year post -posterior instrumentation showing healed lesion and good spinal alignment.

Figure 4 :
Figure 4: a, b, c, d -Pre -operative plain x-rays and MRI of 46 /F showing significant vertebral collapse and kyphosis at L 1 level.e, f -One year post-operative imaging showing excellent correction and spinal alignment.
Bijukachhe et al. / Surgical treatment of tuberculosis of spine: Nepalese experience or cervical involvement.Two patients who had no obvious clinical deformity had multiple dorsal vertebrae involvement but no vertebral body collapse.Wedging of D3 vertebra in one patient exhibited radiological kyphosis, but clinically it was masked by natural dorsal kyphosis.The Cobb angle in the deformity group ranged from 10° to 130°.The average deformity measured in the sagittal plane was 36.6°.Ten patients had deformity along the coronal plane (cervical 1, dorsal 1, dorsolumbar 4, lumbar 4) ranging from 5° to 30° with the average of 2.2°.ESR ranged from 5 to 126 mm in 1 st hour (mean -59 mm in 1 st hour).

Table 1 :
Number of kyphosis and scoliosis in different genders

Table 2 :
Regions, characteristics and severity of deformities in all patients (n=70) He developed weakness on his left sided L 2, L 3 and L 4 myotome.His sensory distribution was normal.Bowel and bladder functions were unaffected.

Table 3 :
American Spinal Injury Association (ASIA) impairment scale grading in all patients (n=70)

Table 5 :
Preoperative and postoperative neurology grading

Table 6 :
Summary of recent studies focusing on surgical outcome

Table 6 :
Summary of recent studies focusing on surgical outcome But in cases with established deformity, though the disease can be eradicated or neurological deterioration can be prevented to some extent, the progression of the deformity cannot be stopped which will eventually lead to a sagittal imbalance in the future.Based on the clinical and radiological findings we have classified tuberculosis into the following categories: 1) Uncomplicated -Patient has pain but no neurological deficit and clinical deformity.Radiologically less than 50% of the vertebral body is destroyed.2) Complicated -Patient has pain but no neurological deficit.He/she has clinical deformity and radiologically more than 50% of vertebral body has been destroyed.3) Complex -The patient has pain and neurological deficit with or without deformity.If the patient has a neurological deficit without deformity it is sub-classified as A, and if there is associated deformity, then B.

Table 7 :
Classification and algorithm of management

Table 7 :
Classification and algorithm of management Bijukachhe et al. / Surgical treatment of tuberculosis of spine: Nepalese experience