The clinician performing the procedure, nursing staff, and in the case of the CT-guided technique, a CT technologist should be present at all times during the procedure. If conscious sedation is required or the patient is under general anesthesia, an anesthesiologist or equivalent certified practitioner may be required to be present based on the facility guidelines. An assistant is often beneficial for preparing the slides for placement of the bone marrow aspirates as well as a container for the biopsy specimen.

The suspected diagnosis should be ascertained prior to performing the procedure to ensure the procedure is being performed for the correct indication. Set institutional guidelines should also be made in cooperation with the pathology department in order to determine how the slides should be prepared for proper pathological examination. The patient may be premedicated if deemed necessary by the clinician in order to safely perform the procedure or for excessive patient anxiety about the procedure. The positioning of the patient is key for multiple reasons, including ease of access to the sampling site, patient comfort, and clinician comfort while performing the procedure.[14] The patient is typically placed in the prone or lateral decubitus position to facilitate access to the posterior superior iliac spine. As with any procedure, the risks, benefits, and alternatives for the procedure should be discussed thoroughly with the patient or their proxy prior to the aspiration and biopsy.

If the CT-guided approach is being utilized, a radiopaque grid should be placed on the patient’s skin over the iliac crest. This will guide the needle entry site. Otherwise, anatomical landmarks should be palpated to guide needle placement. In the case of the posterior iliac crest, the typical needle insertion site is about three fingerbreadths from the midline and two fingerbreadths inferior to the posterior iliac crest. The needle should be inserted angling towards the anterior superior iliac spine. An indentation or pen mark is made on the patient’s skin in the desired location for needle entry. The clinician performing the procedure should don the proper protective equipment, including sterile mask, gown, and gloves. The procedure tray should be opened and organized on the sterile table. The chosen site should be prepped and draped in the typical sterile fashion. Next, 1% to 2% lidocaine solution with a 23-gauge needle should be utilized for local anesthesia. It is essential to anesthetize the periosteum broadly at this step due to the high sensitivity of this structure. A small incision should be made at the skin entry site once the site has been properly anesthetized. The bone marrow needle should be selected next and advanced towards the bone. At this point, if CT-guidance is being utilized, the region of interest should be scanned in the axial plane to determine needle trajectory. Proper needle angulation adjustments should be made, followed by rescanning of the region of interest. Once the proper angulation has been achieved, the needle can be advanced to the periosteum, and the imaging can be repeated as needed. The needle should then be held with the styles in place and advanced into the bone while maintaining gentle forward pressure. A clockwise-counterclockwise back and forth turning motion can be utilized while pushing forward gently. Once the bone marrow cavity has been entered, the stylet can be removed. After attaching a 2 mL syringe to the end of the needle, the aspirates can be obtained. An assistant should then take the sample and prepare the smears on slides or place the sample into the proper tube for further preparation. The stylet can be reinserted if the first attempt at aspiration was unsuccessful, and a new site is required. After proper samples have been obtained, the stylet can be reinserted, and the needle can be removed.

If a biopsy is required, the biopsy needle will next be advanced into the same skin entry site but will be directed at a slightly different angle towards the bone to avoid the previously aspirated site. The needle should be advanced with a greater amount of pressure than previously used into the bone. The needle should then be turned both clockwise and counterclockwise to loosen the sample. With a twisting motion, the needle can then be removed, and the sample can be extracted and placed into the proper container to be sent to pathology. If an insufficient sample has been obtained, a new biopsy needle should be used, and the biopsy process should be repeated.

Post-operative bleeding is common due to the high vascularity of the sampled tissue. Manual pressure or a pressure dressing can be applied to the site until bleeding subsides. Rarely, retroperitoneal or gluteal hemorrhage can occur, which is typically due to injury of the internal iliac artery or superior gluteal artery.[16][17] These cases occur less frequently when the biopsy needle is accurately pointed towards the ipsilateral anterior superior iliac crest and does not exit through the cortex.[18] Hemorrhage, cardiac tamponade, and death can occur if a needle is misplaced during sternal aspiration, and extreme caution should be exercised if this site is chosen for sampling. Infection is at risk of any invasive procedure and can be minimized with proper sterile technique and avoiding areas of superficial infection or osteomyelitis when choosing a sampling site. Tumor seeding is another risk that must be explained to the patient if a biopsy is being performed at the site of a suspected metastatic lesion.[19] 

If the patient is to receive prior imaging, it is important to note the location where the aspiration and biopsy have been performed as the post-procedure changes can result in a false positive reading on positron emission tomography (PET) scanning or a bone scan.[20][21] Damage to local tissues can occur, especially in the case of a non-cooperative or combative patient. Patient compliance should be addressed during procedure planning, and the use of conscious sedation should be considered if necessary.

Bone marrow aspirations and biopsies remain a mainstay for the workup of hematologic malignancies and their definitive diagnosis. These methods avoid more invasive procedures, can yield an accurate diagnosis in a relatively short amount of time, and are relatively uncomplicated to perform. The quick nature of the procedure, the potential for avoidance of sedation or general anesthesia, and the ability to perform the procedure on an outpatient basis facilitate an efficient path towards diagnosis and treatment as well as a nontraumatic experience for the patient.

A potential source of error specifically pertinent to this procedure is the lack of adequate assistance. Utilizing assistants who are aware of the steps of the procedure, how the slides are prepared, and how the biopsy sample is prepared is key to ensuring that the procedure goes smoothly. Ensuring that an assistant is available can aid the clinician performing the procedure so that they may focus on their own tasks. This can also be beneficial to the patient as the procedure time may decrease, and the number of sampling sites may be reduced due to the higher sampling quality. As previously mentioned, communication with the pathology department is also essential for obtaining high-quality samples.

Another clinically relevant point is to properly assess and communicate with the patient both prior to and during the procedure. There are multiple points in the procedure that can cause pain to the patient, including penetration of the periosteum and aspiration of marrow. Proper clinician communication with the patient and/or guardian is essential in order to reduce patient confusion and discomfort. It is the responsibility of the healthcare providers involved in performing this procedure to understand it in its entirety as well as the importance of coordination of care with the end goal of improving patient outcomes.