A good knife requires a skilled operator. Although the No. 14 coarse cutting needle is an excellent tool, its ultimate value depends on the operator's skills and strategies. From preoperative planning to postoperative handling, every step affects the quality of the sample and the success or failure of the diagnosis.

I. Preoperative Planning: Image Guidance and Path Selection

For the biopsy, use a 14-gauge coarse needle. Do not perform the procedure blindly. Ultrasound or CT guidance is a standard procedure.

• Ultrasound guidance: Real-time, non-radiation, it is the preferred method for superficial and some deep soft tissue lesions. The operator can dynamically observe the relationship between the needle tip and the target point, avoiding major blood vessels and nerves. For mixed cystic and solid tumors, ultrasound can also guide doctors to avoid the cystic area and specifically puncture the solid part.
• CT guidance: Applicable to deep lesions that are unclear on ultrasound, such as those in the lungs, mediastinum, and posterior to bones. CT can provide clear anatomical layers, but its drawbacks are radiation exposure and lack of real-time capability.

The core principle of path selection:

1. Shortest distance principle: Under the premise of ensuring safety, select the shortest straight line distance from the skin to the lesion to reduce needle tract damage and bending.
2. Parallel to fascia principle: Try to make the puncture path consistent with the direction of the muscle fascia, avoiding crossing muscle bundles, which can significantly alleviate postoperative pain.
3. Avoid important structures: This is an absolute rule. One must stay away from major arteries, veins, main nerves, as well as hollow organs such as intestines and ureters.
4. Consider subsequent surgery: If it is diagnosed as a malignant tumor, the puncture needle path should be within the resection range of the subsequent radical surgery to enable simultaneous removal and prevent tumor implantation and metastasis.

II. Surgical Techniques: Aim, Stimulate and Withdraw the Needle

1. Targeting and Fixation: Under the guidance of imaging, precisely position the tip of the 14G needle at the edge or inside the lesion. For hard-tissue tumors, gently "probe" the hardness with the needle tip to confirm the location. The operator must hold the needle steadily to prevent slippage.
2. Timing of Excitation: After confirming the ideal position of the needle tip, instruct the patient to hold their breath (especially for thoracic and abdominal biopsies), and then decisively press the excitation button. Hesitation can cause tissue compression and deformation or sample failure.
3. Range Selection: Modern 14G thick cutting needles usually offer two ranges: 15mm and 22mm. For lesions smaller than 2cm in diameter, choose 15mm; for larger lesions, 22mm can obtain a longer and more complete tissue core.
4. Withdrawal of Needle and Hemostasis: After withdrawing the needle body, immediately apply sterile gauze to press the puncture site for at least 5 minutes. For patients with normal coagulation function, this is sufficient to control most bleeding. For high-risk areas (such as liver and kidneys), the pressing time can be extended to 10-15 minutes.

III. Sample Processing: The Crucial Step from the Tip of the Needle to the Slide

After taking out the sample, it is necessary to handle it carefully:

1. Visual inspection: A good sample should be a complete cylindrical structure, white, light yellow, or grayish red, with a smooth surface. If the sample is fragmented, in a paste-like state, or entirely composed of blood clots, it indicates a sampling failure and a re-puncture is required.
2. Fixation and preservation: Immediately place the sample in a specimen bottle containing 10% neutral formalin solution. For samples that need to undergo microbial culture or flow cytometry, use dedicated culture media or normal saline for transportation.
3. Recording and identification: Clearly mark the patient's name, case number, puncture site, and needle number on the specimen bottle. It is advisable to attach a diagram indicating which area of the tumor each sample was taken from (such as the central area, marginal area).

IV. Common Traps and Solutions

• Insufficient sample: This might be due to a too short range or overly hard tissue. Try increasing the range or replacing with a sharper needle.
• Sample breakage: Common in tumors with severe fibrosis. You can try changing the puncture angle or taking another needle at the same location.
• Bleeding: Minor bleeding is normal. If bleeding persists, be alert for possible coagulation disorders or puncturing a major blood vessel. In such cases, an ultrasound re-examination may be necessary.

Mastering these operational points is essential to fully utilize the performance of the No. 14 coarse-cut needle, providing high-quality diagnostic materials for pathologists, and thereby delivering the most accurate diagnosis results to patients.