MSK Interventional Procedures

MSK Interventions - Needle Ninjas

• Core Concept: Precise, image-guided, minimally invasive procedures. Used for diagnosis (e.g., fine-needle aspiration, core biopsy) and therapy (e.g., joint injections, nerve blocks, cementoplasty, tumor ablation).
• Imaging Guidance Selection:

• Pre-Procedure Checklist (📌 "SAFE-C"):
  • Scrutinize Labs: Coagulation (INR ≤1.5, Platelets ≥50,000/μL).
  • Allergies & Anticoagulants: Review and manage.
  • Formal Consent: Ensure patient understanding.
  • Equipment & Antibiotics: Prepare as needed (e.g., for joint procedures).
  • Checklist: WHO surgical safety checklist often adapted.

⭐ Ultrasound is often preferred for soft tissue and superficial joint interventions due to real-time visualization and lack of ionizing radiation.

Joint Interventions - Articular Aces

• Arthrography: Contrast (iodinated, gadolinium) injected into joint for imaging.
  • Indications: Labral tears, ligament injuries, loose bodies, cartilage assessment.
  • Types: Direct (contrast into joint), Indirect (IV contrast, delayed imaging).
• Joint Aspiration (Arthrocentesis): Diagnostic & therapeutic.
  • Diagnostic: Suspected septic arthritis, crystal arthropathy (gout, pseudogout), unexplained effusion.
  • Therapeutic: Relieve pressure, drain hemarthrosis/effusion.

⭐ For suspected septic arthritis, always aspirate the joint before administering antibiotics to ensure accurate culture results.

• Therapeutic Injections: Pain relief, inflammation reduction.

  Agent	Examples	Indications	Notes
  Corticosteroids	Triamcinolone, Methylprednisolone	Osteoarthritis, inflammatory arthritis	Anti-inflammatory, pain relief
  Local Anesthetics (LA)	Lidocaine, Bupivacaine	Diagnostic block, immediate pain relief	Short-acting
  Viscosupplementation	Hyaluronic acid derivatives (e.g., Hylan G-F 20)	Osteoarthritis (knee)	Lubrication, shock absorption; series of injections

• Common Sites: Knee (suprapatellar, parapatellar), Shoulder (glenohumeral, subacromial), Hip, Ankle, Wrist.

MSK Biopsies & Ablations - Tissue Trackers

• MSK Biopsies: Essential for diagnosing bone/soft tissue lesions (tumors, infection, inflammation).

  • Needle Types:
    • FNA (Fine Needle Aspiration): Cytology.
    • CNB (Core Needle Biopsy): Histology; preferred for solid tumors, gives architecture.
  • Technique: Coaxial approach (outer guide, inner cutting needle) allows multiple samples via one puncture, minimizing trauma.
  • Tissue Trackers (Fiducials): Mark biopsy/ablation site for future surgery or radiotherapy planning.

• MSK Ablations: Image-guided, minimally invasive tumor destruction.

  • Radiofrequency Ablation (RFA): Uses high-frequency current to generate heat, causing thermal necrosis.

    ⭐ Radiofrequency ablation (RFA) is the treatment of choice for osteoid osteoma, offering precise thermal destruction of the nidus. Achieves pain relief in >90% of cases.

  • Other Methods: Cryoablation (freezing), Microwave Ablation (MWA).
  • Osteoid Osteoma: Prime RFA indication (nidus typically <1.5 cm).

Intervention Complications - Oopsie Oversight

• Infection (Cellulitis/Abscess):
  • Prevention: Strict aseptic technique (chlorhexidine prep, sterile drapes/gloves).
  • Signs: Local erythema, warmth, swelling, pus, fever.
  • Management: Prompt antibiotics; aspiration/drainage for abscess.
• Bleeding/Hematoma:
  • Prevention: Check coagulation (INR < 1.5, platelets > 50,000); avoid vessels; firm pressure post-procedure.
  • Management: Direct pressure, cold compress; rarely, surgical evacuation.
• Nerve Injury (Neuropraxia):
  • Prevention: Meticulous technique, ultrasound guidance to visualize needle and nerves.
  • Management: Usually transient; supportive. Persistent symptoms: neurology referral.
• Allergic Reaction (Contrast/Anesthetic/Steroid):
  • Prevention: Detailed allergy history; pre-medication if high risk.
  • Management: Antihistamines, corticosteroids; epinephrine for anaphylaxis.
• Post-injection Flare (Steroid Crystal Synovitis):
  • Temporary ↑ pain/swelling at site (24-72h post-steroid).
  • Management: Ice, NSAIDs, reassurance.

⭐ Vasovagal syncope is a common, usually benign, complication during MSK procedures; ensure patient is supine or recumbent.

High‑Yield Points - ⚡ Biggest Takeaways

• Vertebroplasty & Kyphoplasty: Cement for vertebral fractures; Kyphoplasty uses balloon for height.
• Radiofrequency Ablation (RFA): Treats osteoid osteoma (nidus < 1.5 cm); provides pain relief.
• Image-guided Biopsy: CT for deep, US for superficial lesions; core needle for MSK tumors.
• Arthrography: Intra-articular contrast for labral tears, ligament injuries, loose bodies.
• Percutaneous Drainage: For abscesses, hematomas, cysts; US or CT-guided.
• Key Contraindications: Uncorrected coagulopathy, active local infection, patient refusal.