Trends in Spinal Surgery for Pott’s Disease (2000-2016): An Overview and Bibliometric Study

Introduction

Tuberculosis (TB) affecting the human bones and joints has a long historical background. ^{1 –3} It is estimated that 2 million people suffer from spinal TB. ⁴ In endemic areas, it is the most common form of infective spondylodiscitis. The presentation of the disease is variable and bears a strong influence based on the pathogen, stage of the disease, drug sensitivity, and geographical region. With the rise of multidrug resistance TB, the pattern of presentation and treatment has changed to become even more complex. Early identification of the pathogen (biopsy) and initiation of chemotherapeutic medicines prevent many of the severe deformities; surgical intervention is still widely considered and practiced. While the surgical indications broadly include progressive neurological deficit, progressive deformity, instability, pain, and uncertain diagnosis, there is dearth of literature and consensus on the surgical indications, type of surgery, and the outcome. ⁵ There are also regional differences and individual surgeon preferences as far as surgical strategy is concerned that may influence the outcome and disease morbidity. The aims of this study are to evaluate the current trends of surgical intervention in Pott’s disease treatment, identify regional differences in the surgical management, and identify indication for surgical treatment of the disease.

Materials and Methods

Results

Study Selection and Characteristics

Key Question 1. Six randomized controlled trials were identified from our search. We excluded 1 after full-text review for lack of a surgical arm, and we retained 5. ^{6 –10}

Key Question 2. We identified 503 studies from our search strategy and retained 287 meeting our prestated criteria; 266 in adults and 21 in children.

Key Question 3. Sixteen systematic reviews were identified; 5 reported a meta-analysis and were retained. ^{11 –15}

Results of the publication selection are illustrated in Figure 1. Citations of all studies included and those excluded at full text can be found in the supplemental material.

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Figure 1.

Flow diagram showing results of literature search and study selection. KQ, key question.

Key Question 1. What are the surgical indications? Have they changed over time since the year 2000?

Surgical indications for spinal TB as described in RCTs are poorly delineated and inconsistent (Table 1).

Cervical spinal TB. The inclusion criteria for entering the only cervical RCT included cervical myeloradiculopathy, persistent neck pain, difficulty swallowing, and upper extremity weakness. ⁹

Upper thoracic spinal TB. From a single RCT, ineffective control with anti-TB drugs AND one of the following: larger sequestrum formation, or sinus formation, or larger abscess, or vertebral collapse, or progressive kyphosis, or neurologic deficit. ⁷

Thoracic, lumbar spinal TB. One RCT required all of the following: Frankel grading D and E, severe back pain, larger sequestrum formation and significant spinal instability. ⁸

Lumbar spinal TB. One RCT required only a lumbar compression fracture to be eligible for surgery. ¹⁰

Lumbosacral spinal TB. One or more of the following were required for surgery in a single RCT of lumbosacral TB: Spinal cord or nerve root compression causing dysfunction, spinal instability or kyphosis, large abscess, bony cavity, dead bone, sinus tract, resistance to drug therapy. ⁶

There is a lack of evidence to determine whether indications for spinal TB surgery have changed since 2000.

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Table 1.

Inclusion and Exclusion Criteria in Randomized Controlled Trials of Surgical Intervention for Spinal Tuberculosis.

Authors	Spine Location	Intervention and control	Inclusion Criteria	Exclusion Criteria
Elsawaf et al (2013), Egypt	Cervical	Anterior cervical decompression and fusion and anti-TB medication Anti-TB medication alone	All of the following: Cervical myeloradiculopathy Persistent neck pain Difficulty with swallowing Weakness in upper limb	None stated
Lin et al (2015), China	Upper thoracic (T1-T4)	Subscapularis transthoracic approach Posterolateral approach	Ineffective control with anti-TB drugs AND one of the following: Larger sequestrum formation, or sinus formation, or larger abscess, or vertebral collapse, or progressive kyphosis, or neurologic deficit	Liver, heart, kidney dysfunction Highly infectious TB Serious underlying lung disease Age less than 18 years History of upper thoracic surgery Distant stream abscess requiring anterior approach
Qian et al (2016), China	Thoracic, lumbar	Radical debridement, bone graft and instrumentation Posterior instrumentation alone	All of the following: Frankel grading D and E Severe back pain Larger sequestrum formation Significant spinal instability	None stated
Yu et al (2016), China	Lumbar	Anterior debridement JBFT One-stage posterior debridement JBFT	Lumbar compression fracture	Traumatic/neoplastic vertebral fractures Cervical or thoracic TB Intolerance to conventional anti-TB drugs
Jin et al (2012), China	Lumbar, sacral	Single segment fixation, anterior radical debridement, and interbody fusion with bone grafting Short segment fixation and anterior radical debridement and interbody fusion with bone grafting	One or more of the following: Spinal cord or nerve root compression causing dysfunction Spinal instability or kyphosis Large abscess Bony cavity Dead bone Sinus tract Resistance to drug therapy	Unsuitable for pedicle fixation (severe pedicle damage) or osteoporosis from other diseases.

Abbreviations: JBFT, joint bone fixation therapy; TB, tuberculosis.

Key Question 2. What is the current surgical approaches of choice? Have they changed over time since the year 2000? Do they vary by geographical region?

Published studies from 2000 to 2016 report anterior and posterior approaches in similar frequency, with half as many studies reporting a combined approach (Figure 2). Twenty-three percent of studies describe some patients receiving one approach and others receiving a different approach.

Among surgical studies of adults with spinal TB, publications reporting on patients receiving the posterior approach have risen from the least reported approach in the early 2000s to the most frequently reported approach in the past 4 years (Figure 3). Among surgical studies of children with spinal TB, the anterior and combined approaches remain the most frequently published (Figure 4).

The majority of surgical studies in spinal TB arise from China, followed by India, Turkey, and Korea (Figure 5).

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Figure 2.

The number of publications of surgery in spinal tuberculosis, stratified by surgical approach, 2000-2016.

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Figure 3.

The change in the number of publications of surgery in adult spinal tuberculosis, stratified by surgical approach, 2001-2016.

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Figure 4.

The change in the number of publications of surgery in pediatric spinal tuberculosis, stratified by surgical approach, 2001-2016.

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Figure 5.

The number of publications of surgery in spinal tuberculosis, stratified by country originating the study, 2000-2016.

Key Question 3. What are the most common outcome measures following surgery?

Correction of angle/deformity, neurological deficit, bony fusion were the most frequently reported outcomes in published systematic reviews of surgery in spinal TB (Table 2). ^{11 –16} Loss of correction, operation time, blood loss, and hospital stay were also frequently recorded. Only 2 systematic reviews reported on return to activity level.

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Table 2.

Outcomes Assessed in Systematic Reviews of Surgical Interventions for Spinal Tuberculosis.

Outcomes	Jutte (2006) L, T, TL	Zhang (2013) L, T, TL	Muheremu (2015) TL	Liu (2015) L, T, TL	Yang (2014, 2016) L, T, TL
Correction of angle/deformity	×	×	×	×	×
Neurological deficit	×	×		×	×
Bony fusion	×	×		×	×
Loss of correction at last follow-up			×	×	×
Operation time			×	×	×
Blood loss			×	×	×
Hospital stay			×	×	×
Absence of spinal tuberculosis	×	×
Regained activity level	×	×
Complications or adverse events				×	×
Death from any cause	×	×
Change of allocated treatment		×
Erythrocyte sedimentation rate					×

Abbreviations: L, lumbar; T, thoracic; TL, thoracolumbar.

Illustrative Case

A 45-year-old woman of Asian origin presented with inability to walk independently that progressively worsened over past 3 weeks before presentation. She also complained of gradually worsening dull mid-back pain over a period of 2 months. She had control over her bowel and bladder function. On neurological examination, she had 2/5 power in bilateral hip flexor, 3/5 power in bilateral knee extension and ankle dorsiflexion, and 3/5 power in long toe extensors (ASIA impairment scale, AIS C). Abdominal reflex was absent and deep tendon reflexes in the lower extremities were exaggerated (patella, 4+; ankle, 3+; bilateral ankle clonus, 10 beats sustained). She had a sensory level at around T10. She denied any constitutional symptoms. Her laboratory values revealed the following: hemoglobin, 9.3 g%; white blood cells, 6700/μL (4000-11 000); erythrocyte sedimentation rate, 62 mm/h; and C-reactive protein 8.2mg/dL (0-3).

Magnetic resonance imaging scan of the thoracic spine revealed a lesion involving T8-9 disc space with an epidural component that was significantly compressing the spinal cord with a prevertebral collection (Figure 6). A computed tomography (CT) scan of the region showed lytic destruction of the T8 and T9 vertebral bodies (Figure 7) with more than 50% body destruction.

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Figure 6.

Magnetic resonance image (T2-weighted) showing T8-9 spondylodiskitis with epidural collection and significant spinal canal compromise.

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Figure 7.

Computed tomography scan sagittal image showing lytic destruction of the T8-9 vertebral bodies.

A transpedicular CT-based biopsy was done, which revealed presence of acid fast bacilli on Ziehl-Neelsen staining thus confirming the diagnosis of a tuberculous spondylo-diskitis. Culture and antibiotic sensitivity was pending. Her chest CT did not suggest any active TB lesion in the lungs and screening of the remaining spine was negative.

Considering the neurological decline, surgical intervention was considered. She underwent a 2-stage surgery. Stage 1 involved posterior stabilization from T5 to T12 along with T8-9 laminectomy and bilateral transpedicular decompression of the anterior epidural collection. At surgery, there was presence of thick granulation tissue that was found to envelop the spinal cord and bilateral T8 nerve roots. The granulation tissue layer was gently peeled off the neural structures. Stage-2 surgery involved anterior left-sided transthoracic approach with T8-9 vertebrectomy and anterior column support with a structural allograft and supplement fixation with pedicle screws in the vertebral body. The postoperative radiographs are shown in Figure 8.

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Figure 8.

(a) One-year postoperative anteroposterior radiograph showing stable hardware position. (b) Lateral radiograph showing anteriorly placed structural allograft with healing of the lesion.

She was started on 4-drug anti-tuberculous chemotherapy regimen. The culture came out positive for Mycobacterium tuberculosis bacilli and the organism was sensitive to primary drugs.

The patient had a rapid recovery of the neurological status and she was independently ambulatory at 6 weeks and regained complete motor recovery at 3 months (AIS: E). Anti-TB medication was continued till 1 year with close monitoring of her clinical condition and laboratory values.

Discussion

Conclusion

Majority of the current literature is from South Asia. The presence of neurological compromise, deformity and instability were the primary criteria for surgical intervention. In general, the anterior approach in the cervical and cervicothoracic spine and posterior approach in the thoracic and lumbar spine are the preferred approach for adult cases. Deformity correction, neurological deficit, and fusion are among the most commonly used treatment outcome measures following a surgical intervention.