CT-guided biopsy for suspicion of bone sarcomaMedical editor Isabel Lloret MD
Oslo University Hospital
CT-guided biopsy is a precise and gentle way of obtaining representative specimens when there is suspicion of bone sarcoma. The technique has high diagnostic precision, sensitivity, and specificity with regards to malignancy.
For CT-guided biopsy, a cytologist is present to immediately judge the quality of the material either as an aspirate or imprint. It may also be possible to secure material for supplementary examinations such as flow cytometry. Usually, it is important to remove unfixed biopsy material for cytogenetic analysis and genetic investigations.
The CT-guided biopsy should be planned to enable the biopsy canal can be removed within the surgical resection of the specimen.
- Lesion in the bone suspect of sarcoma.
- Obtain representative material of the lesion in order to make a cytological or histological diagnosis.
- Pen for marking
- Scalpel head
- Syringes: 1 x 10–20ml
- Local anesthetic
- Aspiration cannulas, short or long as needed
- Bone needle
- Bone drill
- Tatoo ink
- 8 slides marked with the patient's initials and birthdate in case of smear preparation (three of them marked with the patient's full last name and birth date).
- For CT-guided biopsy in the bone, an antibiotic prophylactic is often administered.
- The procedure is carried out under local anesthesia.
- Deep sedation is considered on an individual basis.
- Full-quality CT scan is taken of the area.
- Access to the biopsy is discussed with surgeons in advance. The biopsy canal must be removed with the tumor if the lesion is a sarcoma.
- A needle is placed as a skin marker of the point of puncture.
- A low-dose live CT scan of the area is taken to check that the location is correct.
- The point of puncture is marked with a pen.
- Local anesthesia is administered periosteally and along the biopsy canal. A live CT scan is repeated to check that the needle is in the correct direction. The rest of the anesthesia is injected and the needle is removed.
- A small incision is made with a scalpel before the biopsy to avoid unnecessary trauma to the skin. The skin will then heal better.
- The biopsy needle is inserted in the incision and pounded into the bone.
- The area is once again monitored by CT to check that the needle is in the correct position and direction.
- The needle is pounded further into the superficial extension of the lesion and the mandrin is removed. The needle is pounded through the lesion with continuous monitoring.
- When the needle is through, it is twisted to maintain the test material within the needle when this is pulled out.
- The biopsy is first put onto the slide and a cytological imprint is made.
- The biopsy is put into Ringers solution or formalin for an histopathological examination.
- The cytology material is stained and examined immediately and the cytologist decides how many more biopsies should be taken.
- The skin at the point of puncture is tatooed.
- The point of puncture is closed with a suture or Steri-strips.
- CT-guided biopsy poses minimal risk for complications.
- For anticoagulation/thrombocytopenia, observe for local bleeding. Compression is applied if necessary.
- The bandage should be kept clean and dry for 4-5 days. Use a shower bandage.
- Strips or sutures are removed after 7-14 days.
- For certain localizations in growth-bearing bones where the biopsy channel goes through the entire bone, the bone can weaken and increase the risk for fractures. Restrictions are considered on an individual basis.