Chemotherapy for Spinal Tuberculosis — Indian Guidelines (NTEP/RNTCP)

Background

Standard Treatment Regimen

Phase 1: Intensive Phase

Phase 2: Continuation Phase

Total Duration: 6–9 months for drug-susceptible spinal TB.

Duration Considerations

Drug Doses (Weight-Based, NTEP)

Delivery Under NTEP

• Daily therapy is the standard (replacing the older thrice-weekly DOT regimen since the 2019 NTEP revision).
• All drugs are provided free of charge through government DOTS centers.
• Treatment is monitored under Directly Observed Treatment, Short-course (DOTS).
• Patients must be notified on Nikshay (India's TB notification portal) — mandatory since 2018 for both public and private sectors.
• Nikshay Poshan Yojana: nutritional support of ₹500/month provided to patients.

Role of Surgery

1. Poor response to chemotherapy with evidence of ongoing infection or deterioration
2. Cord compression with persistent or worsening neurological deficits
3. Spinal instability requiring fixation
4. Large paraspinal abscesses that fail to resolve

Chemotherapy alone is adequate for uncomplicated spinal TB. Multiple trials have shown no additional benefit of surgical debridement over chemotherapy alone (Treatment of Drug-Susceptible Tuberculosis, p. 31).

Adjunctive Corticosteroids

• Indicated when spinal TB is complicated by meningitis (treated as TBM).
• Standard regimen: Dexamethasone 0.4 mg/kg/day tapering over 6–8 weeks.
• Not routinely used for isolated spinal TB without CNS involvement.

Drug-Resistant Spinal TB

Monitoring During Treatment

• Clinical: Pain, neurological status, weight, functional recovery
• Imaging: MRI spine at baseline and ~3–6 months (resolution of abscess, bony fusion)
• Biochemistry: LFTs at baseline and at 2, 4 weeks (hepatotoxicity monitoring — especially with H, R, Z)
• Ophthalmology: Baseline visual acuity and color vision before Ethambutol; monitor monthly

Special Considerations

• Hepatotoxicity: The combination of H + R + Z carries significant hepatotoxic risk. LFTs must be monitored, and a hepatitis protocol (stopping Z first, then H, then R) is followed if drug-induced liver injury occurs.
• HIV co-infection: Antiretroviral therapy (ART) should be started within 2–8 weeks of ATT initiation; Rifampicin interactions with certain ARVs (especially PIs) must be managed.
• Diabetes: Poorer treatment outcomes; strict glycemic control is essential.
• Pregnancy: H, R, E are considered safe; Z is used with caution.

Summary

Chemotherapy Guidelines for Osteoarticular TB (Non-Spinal)

Overview of Sites

• Peripheral joints: Hip, knee, shoulder, elbow, ankle, wrist (tuberculous arthritis)
• Long bones: Dactylitis (TB of short bones of hands/feet — common in children), TB osteomyelitis
• Flat bones: Ribs, sternum, skull, pelvis
• Bursae and tendon sheaths: Tuberculous tenosynovitis, bursitis
• Trochanteric TB, TB of the greater trochanter

Standard Chemotherapy Regimen

According to Treatment of Drug-Susceptible Tuberculosis (p. 31): "Six- to 9-month regimens containing Rifampicin for treatment of bone, joint, and spinal tuberculosis are at least as effective as 18-month regimens that do not contain Rifampicin."

Duration by Site and Complexity

NTEP (India) Guidance

• Category I treatment applies to all new cases of osteoarticular TB:
  • 2HRZE (intensive) + 4HR (continuation) = 6 months total
• Extension to 9 months is permitted at the treating physician's discretion for:
  • Large joint involvement (hip, knee) with bony destruction
  • Slow clinical/radiological response
  • Concurrent immunosuppression (HIV, diabetes, steroids)
• All drugs are given daily as FDCs in weight-based bands
• Treatment is free via DOTS centers and notified on Nikshay

Site-Specific Considerations

TB of the Hip

• Most common and most destructive peripheral joint TB
• 9 months preferred by most Indian orthopedic and ID specialists
• Synovectomy or debridement may be needed for advanced disease (Stage III/IV)
• Total hip arthroplasty (THA) can be done after confirmed disease quiescence (typically 2 years disease-free)

TB of the Knee

• 6–9 months of chemotherapy; synovectomy for refractory synovitis
• Arthroscopic debridement increasingly used alongside chemotherapy

TB Dactylitis (Spina Ventosa)

• Predominantly in children under 5 years
• Responds well to 6 months of standard chemotherapy
• Surgery rarely needed

TB Osteomyelitis (Flat/Long Bones)

• Rib TB, sternal TB, pelvic TB: 6–9 months
• Calvarial TB: 9 months (proximity to CNS)
• Abscess drainage may be required if large or under tension

TB Tenosynovitis / Bursitis

• 6 months of standard chemotherapy
• Surgical drainage/debridement for non-resolving cases

Role of Surgery in Non-Spinal Osteoarticular TB

Monitoring

Key Takeaway

Degas Osteotomy

What Is It?

Historical Context

• THA may be deferred due to active/recent TB
• Young, high-demand patients need a functional, pain-free hip

Principle

The goal is a pain-free, stable, mobile pseudarthrosis or fibrous ankylosis at a functional position.

Indications

Contraindications

• Active, uncontrolled TB (surgery should only follow adequate ATT — minimum 6 weeks to 3 months pre-op chemotherapy)
• Severe acetabular bone loss that makes fixation impossible
• Poor general condition / systemic disease
• Patient preference for THA (if age/activity level appropriate)

Surgical Technique (Overview)

1. Pre-operative ATT: Patient must be on adequate antitubercular chemotherapy for at least 6–12 weeks before surgery, with evidence of disease quiescence (falling ESR, improving general condition).
2. Approach: Lateral or anterolateral approach to the proximal femur.
3. Osteotomy level: Performed at the subtrochanteric or intertrochanteric level of the femur.
4. Displacement:
   • The distal femoral shaft is shifted medially (medial displacement) beneath the proximal fragment.
   • This displaces the femoral head laterally and superiorly, out of the acetabular cavity.
   • The shaft now bears weight through a new contact point against the lateral ilium/acetabular rim.
5. Fixation: The osteotomy is fixed with a blade plate, dynamic hip screw (DHS), or similar device to hold the displacement.
6. Abductor mechanism: Preserved as much as possible; the medialization effectively reduces the abductor lever arm demand and improves muscle efficiency.

Biomechanical Effect

• Medial displacement of the shaft reduces the bending moment at the osteotomy site.
• The body weight is transmitted through the lateral cortex of the femoral shaft against the lateral iliac wall, encouraging fibrous union in a pain-free position.
• The resultant limb shortening (typically 2–3 cm) is acceptable and can be managed with a shoe raise.

Outcomes

Comparison with Other Options for Destroyed TB Hip

Post-operative Management

• Continue ATT for full course (minimum 9 months total for hip TB)
• Non-weight bearing for 6–8 weeks post-op, then gradual mobilization
• Physiotherapy for hip and quadriceps strengthening
• Monitor ESR, CRP for disease reactivation
• Long-term follow-up for potential conversion to THA

Key Points

• The Degas osteotomy is a salvage procedure for the young patient with a TB-destroyed hip who is not yet a THA candidate.
• It works by displacing the femoral head out of the acetabulum, trading a painful, destroyed joint for a functional fibrous pseudarthrosis.
• It requires adequate pre- and post-operative ATT.
• It remains in use particularly in India and other TB-endemic countries as a bridge to eventual THA or as a definitive procedure in resource-limited settings.

Degas Osteotomy of the Pelvis — Clarification & Detail

Important Distinction

1. Degas' Original Pelvic Component in Hip TB Surgery

• A cut is made through the ilium (pelvic bone) just above the acetabulum — this is the pelvic (innominate) component
• Combined with the subtrochanteric femoral osteotomy
• Together, these two cuts allow the entire hip joint complex to be displaced/repositioned

The Pelvic Cut (Iliac/Innominate Component):

• Made through the body of the ilium, typically in a curved or oblique direction above and parallel to the acetabulum
• This frees the acetabular segment, allowing it (along with the femoral head) to be repositioned
• The acetabular fragment can be tilted, redirected, or displaced to improve coverage or to move the destroyed joint out of the weight-bearing zone

2. As a Pelvic Displacement/Shelf Procedure

• An iliac osteotomy above the acetabulum that creates a shelf or buttress of bone
• This redirects or contains the femoral head when the acetabulum has been eroded by TB
• The displaced iliac fragment acts as a biological roof — essentially a shelf acetabuloplasty

Anatomy of the Pelvic Cut

Iliac crest
     |
     |  ← Osteotomy line runs here (oblique/curved)
     |     through the body of the ilium
  Acetabulum (diseased/destroyed in TB)
     |
  Femoral head

• Starting point: Just above the anterior superior iliac spine (ASIS) or along the sciatic notch
• Direction: Curves downward and posteriorly, following the contour of the iliac wing
• Exit point: Near the greater sciatic notch

How the Two Cuts Work Together (Combined Degas Procedure)

1. The femoral head to be moved out of the destroyed acetabulum
2. The acetabular fragment to be tilted to cover or redirect the femoral head remnant
3. A functional fibrous ankylosis or pseudarthrosis to form in a better position

Indications for the Pelvic Component Specifically

Comparison with Other Pelvic Osteotomies

Post-operative Management

• Continue full ATT course (total 9 months minimum for hip TB)
• Non-weight bearing for 8–12 weeks post-operatively
• Gradual mobilization with physiotherapy
• Monitor union at osteotomy site radiologically at 6 weeks, 3 months, 6 months
• Watch for reactivation of TB (ESR, CRP, clinical symptoms)
• Long-term: consider THA once TB has been quiescent for ≥2 years and patient is of appropriate age

Key Points

• The pelvic component of the Degas osteotomy is an iliac/innominate osteotomy above the acetabulum that frees the acetabular segment for repositioning
• It is almost always performed in combination with the femoral subtrochanteric osteotomy — the two together constitute the full "Degas procedure"
• The procedure is a salvage operation for severe TB destruction of the hip in young patients
• It is predominantly described in Indian and French orthopedic literature dealing with TB sequelae
• It requires adequate pre-operative ATT and careful post-operative monitoring

Radiating Pain vs. Referred Pain

Core Definitions

Mechanism in Detail

Radiating Pain

• Occurs due to direct mechanical or chemical irritation of a nerve or nerve root
• The pain impulse travels antidromically along the nerve, producing pain perceived along the entire nerve pathway
• Example: A herniated lumbar disc compresses the L5 nerve root → pain travels from the lower back, down the buttock, lateral thigh, and into the dorsum of the foot (sciatica)
• The brain correctly identifies the general region (the nerve's territory) but the pain is felt along the whole distribution, not just at the source

Referred Pain

• Based on the convergence-projection theory (Chronic Pelvic Pain, p. 20): afferent fibers from visceral organs and somatic sites share the same second-order projection neurons in the dorsal horn of the spinal cord
• The higher cortical centers cannot distinguish which of the two inputs generated the signal, so pain is mislocalized to the somatic (surface) site
• Referral can be:
  • Visceral → Somatic (most common): e.g., cardiac pain felt in the left arm
  • Somatic → Somatic: e.g., hip pathology felt in the knee
  • Visceral → Visceral: e.g., ureteric colic felt in the testis

Classic Clinical Examples

Radiating Pain

Referred Pain

Key Distinguishing Features at the Bedside

The Hip–Knee Example (Clinically Important)

• Hip joint disease (TB hip, AVN, OA) is frequently perceived as knee pain — a form of referred pain via the obturator nerve (L2–L3)
• The patient may present complaining only of knee pain, with a normal knee examination
• Always examine the hip in any patient presenting with knee pain, especially children (Perthes disease, SUFE)

Why the Distinction Matters Clinically

1. Diagnostic accuracy: Treating referred knee pain with knee injections without addressing hip pathology will fail
2. Neurological workup: Radiating pain demands nerve imaging (MRI spine, nerve conduction studies); referred pain demands organ/visceral workup
3. Emergency recognition: Referred shoulder tip pain from diaphragmatic irritation signals a surgical emergency (ectopic pregnancy, splenic rupture, subphrenic abscess)
4. Surgical planning: Nerve decompression addresses radiating pain; visceral pathology treatment abolishes referred pain

Summary

Radiating pain = the nerve itself is the problem; pain travels along the nerve path with neurological signs.

Referred pain = the brain is misled by convergent neural inputs; pain appears at a distant site with no neurological deficit and no direct neural pathway connecting the two sites.