Complete Step-by-Step Operation Of Chiba Needle Fine Needle Aspiration Biopsy (FNA) And Percutaneous Puncture

 A Practical Guide for Interventional Physicians

https://radiopaedia.org/articles/chiba-needle

The clinical use of the Chiba needle must strictly follow aseptic principles and be performed under image guidance (ultrasound/CT/fluoroscopy). The following details the standard operating procedure using the most common CT- or ultrasound-guided solid organ (liver/lung/kidney/thyroid, etc.) fine needle aspiration biopsy as an example.

1. Preoperative Assessment and Preparation

① Patient assessment: Verify indications and rule out contraindications - check complete blood count, coagulation panel (PT/APTT), platelet count (preferably >50×10⁹/L), renal function (if contrast is involved), ECG; inquire about allergy history (iodine/local anesthetics), pregnancy status; use caution in suspected hydatid disease, hemangiomas, severe emphysema, or patients unable to cooperate with breath-holding. ② Image review: Review recent CT/MRI/ultrasound images to determine lesion size, shape, blood supply, distribution of necrotic areas, the optimal puncture plane, and the needle path (avoiding large blood vessels, bronchi, gastrointestinal tract, gallbladder, intercostal neurovascular bundles). ③ Informed consent: Explain the purpose, process, possible complications (bleeding, pneumothorax, infection, rare needle tract seeding), and alternative options to the patient/family, and sign the informed consent form. ④ Instrument preparation: Select a 20G–23G Chiba needle (commonly 21G or 22G, length 15–20 cm),配套 5–10 mL syringes, needle holder, sterile gloves, drape, povidone-iodine/chlorhexidine disinfectant, 2% lidocaine, 10% formaldehyde or 95% ethanol fixative (for cytology smears), glass slides, needle protective sleeve, and if necessary, coaxial guiding needle and 0.018″ microwire.

2. Positioning and Anesthesia

Place the patient in a suitable position (supine/prone/lateral) to bring the lesion closest to the body surface with a safe path. For ultrasound guidance, apply coupling gel to the probe and cover with a sterile cover, determine the optimal entry point and mark it; for CT guidance, perform a local scout scan to determine the surface grid marking point and the needle angle/depth. Disinfect with povidone-iodine in a diameter ≥15 cm for 2–3 passes, and lay a sterile drape. Use 2% lidocaine for infiltration from intradermal and subcutaneous layers step by step to the organ capsule (liver/kidney biopsy requires anesthesia to the capsular layer for better analgesia), paying attention to simulating the biopsy path direction.

3. Puncture and Sampling (Key Technical Points of FNA)

Under imaging monitoring, the operator holds the syringe (attached to the tail of the Chiba needle) with the non-dominant hand, and grasps the needle body near the root (about 2–3 cm from the needle tip) with the dominant hand. Quickly penetrate the skin and superficial tissues along the predetermined angle. Slow down when approaching the target organ, and confirm in real time that the needle tip reaches the edge of the lesion → continue to advance into the interior of the lesion (avoiding central necrosis/calcification areas). After confirming that the needle tip is in a solid portion, withdraw the syringe plunger to create negative pressure (about 2–5 mL negative pressure, never too large to avoid drawing too much blood and diluting cells). Move the needle in a small fan-shaped or rotating motion within the lesion (usually 2–3 times, each about 0.5–1 cm stroke, lasting 1–3 seconds), while maintaining mild negative pressure. Then release the negative pressure (push the syringe plunger back to its original position or loosen), pause briefly in place, and withdraw along the original tract. Throughout the process, instruct the patient to hold their breath according to the preset rhythm (usually at the end of inspiration or at the end of quiet respiration for 2–5 seconds) to reduce needle tip displacement.

4. Specimen Handling

Immediately after withdrawal, gently blow the aspirate from the needle lumen onto a glass slide. Use another slide at a 45° angle to make a thin smear, and immediately fix it in 95% ethanol or Carnoy's solution for cytology. If the aspirate contains tissue fragments, they can also be placed in 10% neutral buffered formalin for histology (but fine needles usually only obtain cytological specimens). For lymph nodes or thyroid, 1–2 repeat samplings can be performed to improve positivity.

5. Postoperative Care and Observation

Apply digital pressure to the puncture site for 5–10 minutes to stop bleeding, cover with a dressing, and instruct the patient not to get wet within 24 hours. After lung biopsy, keep the patient in bed for 2–4 hours and review a chest X-ray to rule out delayed pneumothorax; after liver/kidney biopsy, monitor blood pressure, pulse, and abdominal signs for at least 4–6 hours, watching for intra-abdominal bleeding. Record specimen information (name, site, date, puncture sequence number).

Key Operational Tips:

The Chiba needle has thin walls; avoid excessive forced bending. If resistance is encountered, do not force advancement; adjust the angle instead.

Moderate negative pressure - use smaller negative pressure (2–3 mL) for lungs and thyroid; avoid excessive negative pressure in highly vascular organs to prevent blood contamination.

Orienting the needle tip bevel toward the long axis of the lesion is beneficial for sampling.

Under ultrasound guidance, pay attention to "anisotropy" artifacts;微调 the probe to confirm the true position of the needle tip rather than shadow overlap.

With standardized operation, Chiba needle FNA is extremely safe, with a serious complication rate of <1%, and is the preferred minimally invasive method for obtaining cytological diagnostic evidence.