This technique is particularly well suited for any study that implements a before and after study design or wants to characterize a specific population and does not require excessive amounts of body post tissue. The main advantages are that the technique is relatively cost effective and almost pain free. You can perform multiple biopsies on the same participant on the same day.
This technique can aid the understanding of adipose tissue physiology, in particular the understanding of disease and metabolic function. To begin, ensure that the laboratory has an appropriately private room with clean wipeable, non-porous surfaces, and a clean comfortable bed on which the participant can lie in a supine position. Then using a 70%ethanol spray and clean paper towels clean all required surfaces for the biopsy procedure.
Next place appropriate sharps disposable bins and biohazard waist bags within easy reach of the area where the biopsy will be performed and the person taking the biopsy. Before the participant arrives in the laboratory, set up the equipment required for the procedure on a freshly cleaned general medical trolley. After obtaining written informed consent ask the participant to complete a written questionnaire to ensure they are not allergic to any materials used in this procedure.
After verbally confirming the participant's identity, ensure that the participant understands the procedure to be carried out and potential secondary side effects including bruising, pain, and infection. In addition to written informed consent also take verbal consent from the participant. Next, describe the procedure to the participant emphasizing how the administration of the anesthetic and biopsy may feel.
Also, ensure that the participant is comfortable with proceeding. Again, ensure that the participant has no allergies to the local anesthetic, certain metals and shellfish and that the participant is not taking any form of anticoagulant medication. Once the participant is lying in the supine position identify the biopsy site approximately five to 10 centimeters lateral to the umbilicus.
Next, wash hands with soap and warm water according to standard medical guidelines. And place a sterile sheet on the clean trolley or work area taking care to only touch the outer edges of the sheet. Put on sterile surgical gloves using proper aseptic technique.
Then have the assistant open the rest of the equipment such that it drops onto the prepared sterile sheet without any touching or contamination. Ensure that the assistant does not touch the items when removing them from their sterile wrappings. Next, instruct the assistant to dispense a small amount of iodine based solution on some sterile gauze.
Then disinfect the skin in a spiraling motion moving outward from the proposed biopsy site. Remove excess liquid, if any by wiping with fresh sterile gauze. Verbally confirm the content and the expiry date of the local anesthetic vial with the assistant.
Then instruct the assistant to hold the open vial upside down. And using a 21 gauge needle draw five milliliters of local anesthetic into a syringe. Dispose of the needle into the sharp spin and ensure that the syringe is free of air bubbles.
Next, apply a 26 gauge needle to the syringe and expel any air bubbles. Then gently pinch the abdominal skin and adipose tissue moving it away from the abdominal wall and insert the needle horizontally into the subcutaneous tissue at an angle no greater than 10 degrees relative to the surface of the skin. Next, withdraw the syringe's plunger and additional 0.5 milliliters.
If blood appears in the syringe, withdraw and reinsert the needle at a different angle, then raise a two to four millimeter diameter bleb to anesthetize the insertion area. Advance the needle into the subcutaneous tissue and administer one milliliter of lidocaine in a fan shaped pattern. Remove and dispose of the 26 gauge needle.
Then apply a 21 gauge needle to the syringe and administer the remaining four milliliters of lidocaine in a fan shaped pattern. After five minutes using a sterile scalpel, gently prod the biopsy area to ensure the local anesthetic has taken effect and identify the boundaries of the anesthetized area. Then wait an additional minute or two and reassess.
Once satisfied that the anesthesia is working, gently pinch the skin and adipose tissue and make a small one to two millimeter puncture in the skin. Next, apply a 14 gauge needle to a five or 10 milliliter syringe. Then while gently pinching the skin and adipose tissue, gently insert the needle through the puncture into the adipose tissue approximately centrally in the anesthetized area at an angle no greater than 10 degrees relative to the surface of the skin.
Apply suction by withdrawing the plunger to approximately the 2.5 milliliter mark. Then collect the biopsy by moving the needle in a quick, backward and forwards motion to slice fragments of adipose tissue. After 30 seconds, twist the needle and syringe through 90 degrees and repeat this procedure to break up the fragments of adipose tissue which are then aspirated into the syringe by suction.
After approximately one minute, remove the needle and empty the syringe content onto a layer of gauze covering a wane boat ensuring that the lumen of the needle is facing down to avoid potential blood spatter. Repeat the procedure of biopsy collection a maximum of three times as demonstrated, and check that the participant is content to proceed before repeating the procedure each time. While collecting the additional samples, instruct the assistant to process and prepare the previously collected samples for analysis or storage.
Upon collection of satisfactory samples place one to two layers of sterile gauze over the puncture wound. Then place an ice pack and firmly apply pressure for approximately 10 minutes to induce homeostasis. Once homeostasis has occurred wipe away any iodine based solution or dried blood with sterile gauze, apply an adhesive wound dressing with an absorbent pad to the site.
After checking that the participant feels well provide verbal and written instructions on biopsy site aftercare, emphasizing that the participants will likely exhibit some bruising for the next few days. Clear away used sharps and contaminated materials into designated sharps or clinical waste containers then clean all surfaces used in the biopsy procedure using 70%ethanol and place disposable and non-disposable items of bedding in appropriate clinical bags or disposal or cleaning respectively. In this study 39 subcutaneous adipose tissue biopsies were performed in 11 healthy normal weight females.
Using this procedure, an average of 192 milligrams of sample was obtained. Choosing a biopsy site too close to the umbilicus can lead to unnecessarily extensive bruising. A list of complications experienced by participants following adipose tissue biopsies is summarized here.
Ensure the skin is pinched at all times to avoid the needle from perforating the deeper layer of muscle or perforating through the other side of the skin. Practice makes perfect ensure that the training is performed by a trained physician before attempting it on actual participants. And when inserting the needle to break up the adipose tissue ensure that the person doing the biopsy is certain enough to break up the sample.
