Biopsy and Drainage · IR Playbook

Image-Guided Percutaneous Vertebral Bone Biopsy (-)

Image-guided percutaneous vertebral bone biopsy obtains tissue from a vertebral lesion for histopathology, microbiology, immunohistochemistry or molecular analysis, most commonly under CT guidance. It is preferred to open biopsy when a safe percutaneous corridor exists. Meta-analysis reports a 91% diagnostic yield, 86% diagnostic accuracy and approximately 1% overall complication rate for CT-guided spinal lesion biopsy.

Learning objectives

• Select the vertebral target and safest approach using CT, MRI and, when relevant, PET-CT.
• Perform coaxial vertebral sampling while protecting the neural, vascular and visceral structures.
• Allocate specimens correctly for tumour characterization or suspected infection.
• Recognize and manage haemorrhagic, neural, pleural and infectious complications.

Indications

• Histologic characterization of an indeterminate focal or diffuse vertebral lesion.
• Confirmation and subtyping of suspected primary vertebral tumour or metastasis when tissue will alter treatment.
• Acquisition of tissue for immunohistochemistry, receptor testing or molecular analysis.
• Suspected vertebral osteomyelitis or spondylodiscitis when blood cultures and other noninvasive investigations have not established the pathogen.
• Atraumatic vertebral collapse of uncertain cause requiring differentiation among osteoporotic, malignant and inflammatory or infectious disease.
• Persistent or progressive vertebral abnormality with discordant clinical and imaging findings.

Absolute contraindications

• Absence of a safe percutaneous access route.
• Uncorrectable clinically important coagulopathy.
• Patient refusal or absence of valid consent.

Relative contraindications

• Haemodynamic or respiratory instability.
• Uncooperative patient without suitable sedation or general-anaesthesia support.
• Pregnancy when ionizing-radiation guidance cannot be avoided.
• Local infection along the proposed entry tract.
• Highly vascular lesion or vascular malformation without adequate vascular assessment.
• Unstable spine, epidural compression or neurologic deterioration requiring urgent surgical management.

Equipment

• Multidetector CT scanner with CT-fluoroscopy capability when available; fluoroscopy or cone-beam CT may be used for selected well-visualized targets.
• Sterile preparation set, drapes, scalpel and 18–20G peripheral intravenous cannula.
• 1–2% lidocaine, typically 10–20 mL, with syringes and 22–25G superficial and 20–22G deep infiltration needles.
• Coaxial trephine or drill-assisted bone-biopsy system, commonly 11–14G, with length selected from CT measurements.
• 14–18G semi-automatic or automatic core-biopsy needle for an accessible soft-tissue component.
• 18–22G aspiration or spinal needle and 10–30 mL syringes for fluid aspiration or cytology when indicated.
• Sterile dry or saline microbiology container, blood-culture bottles when locally validated, and separate containers for aerobic, anaerobic, mycobacterial and fungal studies.
• 10% neutral buffered formalin container for histopathology and separately arranged fresh medium for flow cytometry or molecular testing when required.
• Monitoring, oxygen, suction, resuscitation equipment and immediate access to haemostatic material when tract embolization becomes necessary.

Procedure steps

1. Perform a formal time-out and correlate scout images with diagnostic CT and MRI to confirm the patient, vertebral level, side and required tests. Mark transitional anatomy or vertebral-numbering variants explicitly.Pearl: Count from a fixed landmark on whole-spine imaging when segmentation is uncertain.
2. Position the patient and obtain planning CT images. Choose the shortest safe route that reaches viable tissue without crossing the spinal canal, neural foramen, major vessel, pleura, bowel or an avoidable tissue compartment.Pearl: Apply the 3 Ps: planning, positioning and protection of critical structures.
3. Before puncture, confirm the number and type of specimens required with pathology and microbiology. Label separate containers for histology, routine cultures, mycobacterial testing, fungal testing, flow cytometry or molecular analysis as clinically indicated.
4. Use sterile technique and infiltrate local anaesthetic from the skin through the paraspinal muscles to the periosteum. Make a small skin incision for the large-bore cannula and administer titrated sedation if required.Pearl: Adequate periosteal anaesthesia is essential because cortical contact and drilling are painful.
5. Advance the coaxial bone cannula incrementally to the selected cortical entry point with intermittent CT confirmation. For a transpedicular route, keep the cannula within the pedicle and preserve the medial and inferior cortices.
6. Seat the cannula perpendicular to the entry cortex to reduce slippage, then advance the trephine or drill using controlled rotation. Reconfirm trajectory after cortical purchase and before advancing toward the lesion.Pearl: Sclerotic lesions require an appropriate cutting trephine or drill-assisted system rather than forceful advancement of a soft-tissue needle.
7. Advance into the viable target and obtain multiple representative cores through the coaxial cannula while minimizing repeated cortical punctures. Redirect within the lesion when necessary without leaving the established safe corridor.Pearl: If both bone and an accessible soft-tissue component are abnormal, dual sampling may improve the chance of a definitive diagnosis.
8. Aspirate any fluid before irrigating or obtaining additional cores. For suspected spondylodiscitis, submit aspirate and tissue for aerobic and anaerobic culture and histopathology, adding mycobacterial, fungal, Brucella or molecular testing according to epidemiology and host factors.Pearl: In India, suspected tuberculous spondylitis requires deliberate allocation for mycobacterial culture and validated molecular testing; formalin-fixed tissue alone is inadequate.
9. Inspect cores for visible tissue and place each specimen immediately into its designated container. Obtain touch preparation or rapid on-site assessment when available, particularly when tissue is scant or lymphoma is suspected.
10. Replace the coaxial stylet and withdraw the system under control. Apply local pressure, dress the puncture site and obtain immediate CT images through the tract and target to exclude haematoma, pleural injury or other acute complication.Pearl: Persistent tract bleeding may be treated through the coaxial cannula before it is completely removed.

Complications

• Transient biopsy-site pain
• Haemorrhage, paravertebral haematoma or segmental-artery pseudoaneurysm
• Nerve-root, spinal-cord or dural injury
• Pneumothorax or pleural injury
• Biopsy-related infection
• Needle-tract tumour seeding

Exam pearls

• The preferred route is transpedicular when feasible, but the lesion—not habit—determines the approach.
• Never cross the medial or inferior pedicle cortex: medial breach threatens the canal and inferior breach threatens the exiting root.
• For suspected spondylodiscitis, obtain fluid when present and sample abnormal disc and adjacent endplate or bone.
• In suspected spinal tuberculosis, reserve unfixed material for mycobacterial culture and molecular testing; do not place every specimen in formalin.
• Radiology-pathology discordance after a benign or nondiagnostic result requires reassessment or repeat biopsy.
• For a suspected primary bone tumour, coordinate the biopsy tract with the surgeon so it can be excised during definitive surgery.

Viva questions

Why is CT preferred for vertebral biopsy?

CT provides precise visualization of cortical bone, the pedicles, spinal canal, neural foramina, vessels, pleura and viscera. It permits accurate measurement of the entry angle and depth and immediate assessment for complications.

What is the preferred approach to a vertebral-body lesion?

The **transpedicular approach** is preferred when the pedicle safely accommodates the needle because it provides a short, predominantly osseous corridor and limits violation of additional tissue compartments. The approach must be changed when lesion position, pedicle size or vertebral level makes it unsafe.

What are the 3 Ps of vertebral biopsy?

They are **planning**, **positioning** and **protection**. The operator selects the target and trajectory, positions the patient to reproduce that trajectory and protects the neural, vascular, pleural and visceral structures.

What specimens should be sent in suspected spondylodiscitis?

Send aspirated fluid and tissue for aerobic and anaerobic culture plus histopathology. Add mycobacterial culture and validated molecular testing, fungal culture or Brucella testing according to epidemiology, imaging and host risk factors.

Should antibiotics be stopped before biopsy for suspected vertebral osteomyelitis?

IDSA considers withholding antibiotics for **1–2 weeks** reasonable when clinically feasible because prior therapy may reduce culture yield. Antibiotics must not be delayed in sepsis, haemodynamic instability, neurologic compromise or impending cord compression.

What should be done after a nondiagnostic vertebral biopsy?

First confirm level, target, specimen adequacy and radiology-pathology concordance and perform testing for difficult-to-grow organisms when infection remains suspected. Repeat image-guided biopsy, percutaneous endoscopic sampling or open biopsy should then be discussed according to the clinical problem.

What diagnostic performance should be quoted for CT-guided spinal biopsy?

A 2021 meta-analysis reported **91% diagnostic yield**, **86% accuracy per procedure** and approximately **1% complication rate**. Accuracy among biopsies that produced a diagnosis was 94%.

References