Bone Biopsies: Practical Considerations and Technical Tips

Abstract

Percutaneous image-guided needle biopsies are a safe and minimally invasive method of obtaining tissue of bone lesions. Radiologists are an integral part of a multidisciplinary team (MDT) approach to patient care in obtaining tissue for both pathologic diagnosis and advanced genetic/molecular testing. By utilizing image guidance, radiologists can target bone lesions with a very low complication rate. This review will discuss our approach to image-guided biopsies of bone lesions. Radiologists should be familiar with patient selection and imaging workup prior to performing biopsies, as well as the importance of coordinating the biopsy approach and sampling with the patient's clinical team. Management of bleeding and thrombotic risk in patients undergoing bone biopsies is also an important preprocedural consideration and will be discussed. The majority of bone biopsies are performed utilizing moderate sedation for patient analgesia and comfort, but close attention should be paid to patient comorbidities and potential interacting medications. Although computed tomography guidance remains the mainstay of image-guided biopsy, there are some circumstances in which ultrasound or fluoroscopic guidance may be beneficial. New advances in powered drill technology have made tissue sampling of bone lesions particularly sclerotic bone lesions both safer and faster with increased tissue yield. Finally, we will discuss image-guided biopsy of difficult anatomic regions that require special techniques to yield tissue safely.

Over the past two decades, percutaneous biopsies have become a commonly performed, minimally invasive, and cost-effective modality for obtaining tissue of both malignant and nonmalignant bone lesions. ^{1 2} While bone biopsies were traditionally performed using an open surgical technique, percutaneous biopsies including fine need aspiration and core needle biopsy (CNB) have become a preferred approach due to the decreased morbidity of the procedure. ^{3 4 5} Percutaneous bone biopsies have been shown to have a low complication rate, high positive predictive value, and a high correlation to surgical pathology. ⁶ Bone biopsies have been increasingly demonstrated to add value to patient care through the identification of alternative diagnoses of benign lesions and diagnosis of new malignancies even in the setting of a known malignancy. ^{7 8} Additionally, as the clinical management of malignancies advances in the era of personalized medicine, the role of image-guided percutaneous biopsies will similarly continue to evolve. Bone biopsies now not only provide a histological diagnosis but may also allow for an analysis of biomarker status and cellular pathway-targeted management. ⁹

As imaging and biopsy technology has expanded, radiologists are playing an increasingly integral role as proceduralists performing percutaneous bone biopsies. In fact, bone biopsies performed by expert radiologists were correlated with improved diagnostic accuracy further highlighting the importance of bone biopsies as a component of an interventional radiology practice. ⁵ As the provision of medical care increases in complexity, radiologists must remain involved in the multidisciplinary care of patients with bone lesions and strive to continue improving the safety and diagnostic yield of bone biopsies. In this article, we provide a practical review of bone biopsies and technical considerations when performing the procedure.

Preprocedural Planning

Multidisciplinary Coordination

Preprocedural planning is critical to maximizing the efficacy and safety of performing a bone biopsy. Multidisciplinary team (MDT) approaches to patient care have grown significantly over the past two decades and have become nearly commonplace in caring for cancer and other complex pathologies. Accordingly, studies have demonstrated that MDT meetings are often responsible for changes in diagnoses with alterations of treatment plans and implementation of discussed plans in 90 to 100% of discussed patients. ¹⁰ Additionally, the value of an MDT in providing care in bone and soft tissue sarcomas has been well described citing logistical benefits, information transfer of clinical information, quality improvement mechanism, and education at all levels. ¹¹ Radiologists play an important role as diagnostic specialists in the MDT. ¹¹ Collaboration with pathology, surgery, and oncology to create a biopsy protocol has been demonstrated to have only a 1.1% rate of major diagnostic errors and 100% positive predictive value in musculoskeletal masses. ⁶

The pre- and postprocedural care and planning will be enacted by the patient's primary clinical providers. It is necessary to coordinate and understand the diagnostic questions that may be answered by the bone biopsy. Indications should be reviewed with medical or surgical providers to ensure the appropriateness of the procedure. Indications may include suspicious primary bone tumors, suspicious metastatic bone tumors, molecular receptor characterization, characterization of a nontraumatic fracture, microbiological analyses in suspected bone infections, recurrence identification of following bone tumor excision, or quantification of treatment response. ⁴ Technical considerations for future operative planning should be discussed if surgical resection may be warranted upon diagnosis. Reviewing the indication of the procedure with the clinical team will allow for procedural planning and optimization of diagnostic yield. The suspected and differential diagnosis may also guide biopsy specimen handling. Most specimens are placed in formalin for permanent preservation; however, specimens must be analyzed in fresh saline for flow cytometry if lymphoma is suspected. ¹ As the provision of cancer care moves toward biomarker and next-generation sequencing, specimen preservation and handling may continue to change in the coming years. ¹² A MDT approach also allows for education and awareness of postprocedural complications most notably bleeding, hematomas, or injuries to other structures if patients were to re-present to the clinic.

Patient Evaluation

Preprocedural case review and patient preparation are important steps prior to a bone biopsy. The preprocedural review allows for the mitigation or preparation for potential procedural complications, most notably bleeding or sedation-related morbidity. The Society of Interventional Radiology (SIR) clinical 2018 practice guidelines for moderate procedural sedation and analgesia ¹³ recommend a detailed review of the medical record and patient interview with examination in consultation with medical specialists as appropriate. Particularly relevant aspects for consideration include organ system dysfunction, difficult airway, prior adverse events with anesthesia, or a history of substance or tobacco abuse. ¹³ Medications should be reviewed for potential sedating or interacting medications. Additionally, the patient's vital signs or clinical stability and American Society of Anesthesiologists (ASA) status should also be reviewed. ¹³ Moderate conscious sedation with local anesthesia is typically appropriate for a bone biopsy. Consultation with an anesthesiologist or provision of general anesthesia may be required for higher-risk procedures or in higher-risk patients. ^{1 13}

Management of bleeding and thrombotic risk in patients undergoing bone biopsies is also an important preprocedural consideration. The main contraindications to bone biopsies are related to the bleeding risk. ⁴ Patient factors that affect thrombosis and coagulation should be reviewed, in particular, medical history (kidney or liver dysfunction, hyper/hypocoagulable state) and medications. The SIR provides consensus guidelines detailing recommendations for performing percutaneous interventions including bone biopsies. ¹⁴ The risk of thrombosis should be thoughtfully balanced with the risk of bleeding for each individual patient. Cancer is associated with thrombosis creating an inherent hypercoagulable state in many patients who require a bone biopsy. ¹⁵ The potential mortality of thrombotic events may be high: 17.5% for mechanical valve thrombosis, 37% for embolic stroke, and 5 to 10% for venous thromboembolism. ¹⁶ Bone biopsies have been stratified into the high bleeding risk category with guidelines recommending an INR ≤ 1.5 to 1.8 and platelets > 5 × 10 ⁹ /L. ¹⁴ Patients requiring bone biopsies may also frequently be on anticoagulants and/or antiplatelet agents. A careful review of the medications and their indications is required in the preprocedural assessment. SIR guidelines exist with recommendations for timing of holding and resuming each antiplatelet agent as able. ¹⁴ As bone biopsies are largely elective, nonurgent procedure medications should typically be held per guidelines and blood product transfused prior to the procedure.

Preprocedural Imaging

Preoperative imaging review is essential in planning an imaging-guided percutaneous bone biopsy. As biopsies can result in potential patient morbidity, we should aim to stratify an appropriate differential and ensure the biopsy would provide management-altering information. In participation in the patient's MDT, interventional and diagnostic radiologists can discuss necessary preprocedural imaging to characterize and localize the bone lesion. As we have rapidly increased the use of cross-sectional imaging over the past two decades, we have accordingly increased the detection of incidental findings. ¹⁷ Bone lesions can often be fully characterized solely with imaging findings making them lesions that do not warrant biopsy or “do-not-touch lesions.” ¹⁸

Bone lesions are often best assessed using a variety and combination of imaging modalities. Radiographs have remained the optimal initial imaging for evaluating and characterizing osseous lesions. ^{18 19} Lesions can quickly be classified into aggressive or nonaggressive categories through an evaluation of matrix mineralization, margins, bone destruction pattern, or periosteal reaction. ¹⁸ Many do-not-touch lesions can be identified through characteristic radiographic appearance only. Additional imaging with computed tomography (CT) scan can show a detailed assessment of the radiographic features and offers a three-dimensional cross-section of the lesion. Magnetic resonance imaging (MRI) is particularly helpful for bone marrow abnormalities, neurovascular bundle status, and joint involvement. ¹ However, MRI is expensive, time-consuming, and should be used in combination with other imaging for characterization of lesions. ¹⁸ Adjunct imaging modalities include 99mTc–methylene diphosphonate bone scintigraphy and positron emission tomography (PET) CT scans. Both may provide clues to parse out the differential diagnoses of bone lesions prior to biopsy.

Ultimately, appropriately characterizing bone lesions prior to embarking on a biopsy is important and should be discussed with the MDT. Cross-sectional imaging with CT and MRI serves to determine the appropriateness of the procedure as a tool for bone biopsy procedural planning.

Imaging Modality Selection

There are a variety of potential imaging modalities available for image-guided bone biopsies. Most commonly used in clinical practice are CT, ^{1 4} fluoroscopy, and ultrasound (US) guidance, ²⁰ though MRI and PET/CT are also potential options. CT guidance has currently become the first-line imaging tool for bone biopsies when available. ^{1 4} CT-guided bone biopsies are feasible and safe for bone biopsies in nearly all skeletal sites for biopsy. ⁴ The advantage of CT is the ability to provide excellent three-dimensional localization of the lesions and improved identification of surrounding structures. ²¹ The diagnostic yield has been studied in retrospective reviews and case series demonstrating up to 94% final diagnostic accuracy. ^{21 22} In cases with nondiagnostic biopsies, it has been demonstrated that similar challenges were also associated when performing an open biopsy. ²³ Diagnostic yield has also been demonstrated to vary by type of lesion with lytic lesions versus sclerotic and larger (≥3 cm) lesions. ²¹ Additionally, CT has been demonstrated to be a viable localizing modality for CT occult lesions using anatomic landmarks and needle visualization. ²⁴

While US-guided biopsies are less common than CT, they offer some advantages including lower cost, faster procedure time, no radiation, and improved vascular assessment with Doppler. ²⁰ US is limited for certain biopsy locations notably the skull and craniovertebral junction, intraosseous lesions of the spine, or vertebral body. ²⁰ US is a viable option for many other anatomic locations including the sternum, pelvic bones, and appendicular skeleton. ²⁰ US may also be limited by the depth of the lesion, echogenicity of the cortex, and comfort of the proceduralist with the modality. ²⁵ With an intact cortex, US beams are attenuated leading to the inability to visualize the lesion in the medullary space. ^{26 27} US may also be augmented by fusion imaging, overlaying the live US image over an uploaded CT or MRI, and needle tracking to improve the needle tracking in an intact cortex. ²⁶ The reported diagnostic yield of US-guided biopsies is similar to that of CT-guided biopsies with a systematic review reporting 78 to 100%. ²⁸ Similarly, US can be used for both lytic and sclerotic lesions with sclerotic lesions similarly linked to lower diagnostic yield. ²⁵

Historically, bone biopsies have been performed using fluoroscopic guidance. As CT has become more readily available, it has become the most commonly used imaging modality. Fluoroscopic biopsies have been demonstrated to require a shorter procedure time and less radiation exposure than CT-guided biopsies. ²⁹ The disadvantage to fluoroscopic biopsies is the lack of surrounding soft tissue visualization and limited with smaller lesions. Similar to US fusion imaging, real-time fluoroscopy has been combined with CT images with navigation and tracking to facilitate biopsy. ³⁰ This may be particularly beneficial in special populations such as children who would benefit from the minimum possible radiation exposure. Both MRI and PET/CT have been used as modalities for real-time image-guided bone biopsies. These modalities may be useful for CT occult lesions that are increasingly demonstrated with the addition of MRI and PET/CT into many cancer algorithms. The availability of real-time MRI or PET/CT biopsy is limited by institution. Both modalities have been demonstrated to have high diagnostic yields (>90%) ^{31 32} and serve as important potential options for image guidance.

Equipment Selection

The initial consideration in equipment selection is determining whether a fine needle aspiration (FNA) or CNB is indicated. The type of biopsy should be made with consideration of differential diagnoses investigated, as FNA does not offer histological architecture often limiting the diagnostic value. ^{33 34} FNA does, however, offer advantages such as lower cost, greater efficiency, and fewer complications, particularly when targeting soft and lytic lesions. ³⁵ While FNA retains some utility, more recent research demonstrates a preference for CNB. ³⁶ CNB uses larger needles, typically 18 gauge or larger, which preserve tissue architecture and cellular patterns. ^{37 38 39} Among the various CNB systems on the market, there is a considerable degree of technological overlap.

Soft tissue and lytic bone lesions are typically biopsied using side-cutting needles, most commonly Tru-Cut (Merit Medical) biopsy systems. ^{40 41} These systems utilize an outer cutting cannula with an inner slotted stylet. Once inserted into the target lesion, the inner stylet is then advanced further and then retracted back into the cannula with the sample captured by the slotted portion of the needle. ⁴⁰ There are now many semiautomatic/automatic options on the market with multiple studies showing improved diagnostic accuracy compared to their manual counterparts. ^{42 43 44} Additionally, side-cut systems ( Fig. 1 ) can be used through coaxial systems as described later. ³⁹

Fig. 1.

( a ) Initial axial CT of a destructive sternal lesion (arrow). ( b ) Ultrasound-guided biopsy of the lesion using a spring-loaded side-cutting device (arrow).

For sclerotic lesions or those covered by an intact cortex, coaxial systems are the most commonly used systems. ¹ It is worth noting that non-coaxial systems, such as the Jamshidi (BD) needles, have been used since 1971. ⁴⁵ Noncoaxial systems operate by introducing the needle into the target lesion and subsequently removing a central stylet. The needle is then further advanced into the lesions with manual rotation to obtain a tissue sample within its central portion. While this system is both simple and effective, its primary limitation is the ability to only obtain a single sample with each insertion. ⁴⁵ In comparison, coaxial systems involve the manual introduction of a cannula and central stylet in the target lesions with subsequent removal of the stylet. Multiple biopsy needles can then be passed through the cannula, allowing for the collection of multiple samples. The advantages of coaxial systems include reduction of tumor spread/adjacent tissue seeding, diminished iatrogenic injury to surrounding structures, and improved efficiency when collecting multiple samples. ^{1 46} Many of the differences between the various systems are centered around technical aspects of the cutting end of the cannula/needle, such as those with serrated teeth (trephine). ⁴⁷ The leading cutting surfaces can dramatically impact the quality of the sample and how much nondiagnostic material, including “crush artifact,” is included. ^{48 49}

Prior to 2012, coaxial systems required manual advancement of the needle and cannula into the bone lesions. In more recent years, there have been multiple, powered drill-style systems developed. While manual drill styles, such as the Bonopty (AprioMed) systems, are particularly useful in cases in which the target lesion requires precise placement ( Fig. 2 ), multiple studies have demonstrated multiple advantages of using powered systems. Some of these advantages include decreased procedure time, radiation exposure, and experienced pain. Additionally, crush artifact/fragmentation of the sample can destroy the tissue architecture leading to a nondiagnostic sample. Powered systems have been overall found to have a lower rate of crushing and fragmentation of the sample as compared to manual systems resulting in increased diagnostic yield. ⁵⁰ Of the powered drill systems on the market, the Arrow OnControl (Teleflex) was the first of these systems to become commercially available and remains one of the most commonly used ( Fig. 3 ). ⁵⁰ The Trek (BD) is another powered drill system that advertises increased drill speed control and automatic drill braking when the trigger is released. Multiple examples of these systems and their various augmentations are shown below.

Fig. 2.

( a ) Initial axial CT of a lytic lesion within the proximal humeral head. ( b ) CT-guided biopsy of the lesion using an anterior approach with a spring-loaded side-cutting device.

Fig. 3.

( a ) Initial axial CT of an intramedullary lesion of the distal humerus. ( b ) CT-guided biopsy of the lesion using a lateral approach with the OnControl powered drill biopsy system.

Procedure Technique

General Technical Considerations

As briefly discussed, bone biopsies are typically performed under moderate conscious sedation with additional local anesthesia. ⁵¹ General anesthesia is often considered only for complex cases, particularly long procedures, pediatric patients, uncooperative patients, and/or patients with high narcotic tolerance. ¹ The 2018 SIR clinical practice guidelines for moderate procedural sedation and analgesia ¹³ should be referenced for more information regarding procedural sedation. Local anesthesia is typically administered using a small caliber needle, often 23G, to inject 1% buffered lidocaine within the tissues surrounding the planned biopsy site. Injection of local anesthetic should be throughout the subcutaneous tissue and to the level of the periosteum. A long-acting local anesthetic, such as ropivacaine or bupivacaine, can be added in particularly painful locations and/or in prolonged cases. ⁵² Currently, there are no formal recommendations on effectively reducing pain during biopsy and the patients should be appropriately counseled prior to the procedure. ⁵³

The patient should be positioned with the goal of preserving patient comfort while facilitating an ergonomic approach that avoids critical structures and provides a diagnostic sample. ⁵⁴ Once appropriately positioned, a sterile field can be established in standard fashion using the draping supplies often provided with the selected needle kit. The biopsy needle insertion technique will depend on the type of needle system selected and the target site. Anatomic considerations and associated complications vary based on the target site and will be discussed in the following sections. Additionally, in all cases, coordination with surgical oncology is recommended when planning the approach.

Calvarium, Skull Base, and Cervical Spine

Primary skull neoplasms are rare with an incidence rate of less than 1% of all bone tumors. ^{55 56} Preprocedural planning should include discussions with neurosurgical and/or ear, nose, and throat surgeons regarding the planned approach and strategies to minimize potential complications. ⁵⁷ Imaged-guided biopsy of a skull or cervical spine lesion using CT guidance is essential in all cases. ⁴ A prebiopsy CT or MRI is typically performed to determine the exact location of the lesion and what position the patient should be placed in. Positioning of the patient, whether in supine, prone, or lateral decubitus, should facilitate an angled approach of 30 to 60 degrees to the surface to minimize the risk of penetration into the underlying intracranial structures. ⁵¹ However, this angled approach should be performed with caution, as it increases the chance of needle slippage. ⁵¹ Beveled cutting tip coaxial systems are often used in these cases as they provide better surface grip. ⁵⁸ The technical approach will vary based on the exact site of the biopsy—calvarial, orbital, or skull base. Gupta et al provided specific anatomical and technical considerations for more challenging areas, specifically with regard to the skull base and cervical spine for which there are many possible approaches that vary based on the location of the lesion. ⁵⁸ Within the head, skull base, and suprahyoid neck, multiple approaches have been described including subzygomatic, retromandibular, paramaxillary, submastoid, transoral, and posterior. In the infrahyoid neck and lower cervical spine, an anterolateral approach between the carotid sheath and airway, a posterolateral approach posterior to the carotid sheath, and a posterior approach have all been described. Regional-specific complications include the formation of hematoma and/or penetration into the underlying intracranial structures with resulting neurologic injury. ⁵⁷ While the complication rates and safety of skull biopsies have not been extensively studied, the few available studies show complications to be rare. ^{57 59}

Thoracic and Lumbar Spine

Biopsy of thoracolumbar spinal lesions is typically performed using fluoroscopy guidance with CT used in a subset of cases. ⁶⁰ Similar to the cervical spine, the approach for spinal interventions varies by the location/level of the target lesion. In the thoracic spine, lesions can be targeted using a transpedicular, transcostovertebral, or posterolateral paravertebral approach. ⁶¹ The transpedicular approach is typically used for lesions located within the posterior portion of the vertebra body or pedicle, particularly when curative resection is a possibility. ^{60 62} Caution should be taken when performing a transpedicular approach in the upper thoracic spine as the pedicles are small which increases the chance of fracture or breach of the pedicle. ⁶⁰ One of the advantages of this technique is the ability to utilize the groove between the transverse and mammary processes to guide the needle into the pedicle. ⁶³ In comparison, a transcostovertebral approach is typically used for lesions along the vertebral body endplates or within the disc space. ⁶² The advantages of this approach are the ability to utilize the groove between the transverse process and rib along with, when using more lateral needle angulation, access to more of the vertebral body. This angled approach can allow for better access to the posteromedial portion of the vertebral body which is an advantage over the transpedicular approach. ⁶⁰ Finally, the posterolateral approach is typically used only when the aforementioned approaches are not anatomically feasible, as it requires dissection through the extrapleural space. ⁶⁰ In all of these approaches, there is the risk of iatrogenic injury, including pneumothorax/hemothorax, and damage to the lung parenchyma and/or underlying vital structures, such as the aorta. ⁵¹

In the lumbar spine, a transpedicular approach is used in the vast majority of cases due to the large caliber of the pedicle and the ability to access the entire vertebral body. ⁶⁰ In rare cases when the transpedicular approach is not feasible, a posterolateral approach has been described adjacent to or through the psoas musculature. ⁶³ Care should be taken to avoid the needle slipping anteriorly which could cause a hematoma or penetration into vital structures such as the IVC and aorta. Additionally, the needle tracking posteromedial into the neuroforamina should similarly be avoided. ⁶³ Finally, for the sacrum, CT is the preferred imaging modality. ⁴ A direct posterior approach can be performed in the vast majority of cases. ⁶⁴ While this direct posterior approach is sufficient for most lesions, a transforaminal approach can be performed if there is clear visualization of the sacral foramina and nerves. ⁶⁰ Additional approaches to consider, although considered nonresectable, include more laterally angulated and transiliosacral approaches which carry significant risks including seeding the surrounding tissues/joints and accidental penetration into the bowel. ⁶⁰ Complications related to the biopsy of the spine are rare ranging from 3.3 (CT) to 5.5% (fluoroscopy), with a statistically increased rate associated with larger biopsy needles. ⁶⁵

Ribs and Sternum

For the biopsy of both the sternum and ribs, CT guidance is the preferred imaging modality. ^{4 66} In cases in which the lesion has an extraosseous component, US can be considered ( Fig. 1 ). ⁶⁷ Additionally, if the lesion is mostly sclerotic, fluoroscopy can also be considered. ⁶⁷ Similar to the skull, a low needle approach angle of 30 to 60 degrees is typically recommended to reduce the risk of penetrating the underlying structures. ⁵¹ Again, bevel-tipped needles are preferred for better surface grip and decreased slippage. ⁵⁸ Another approach, sometimes called “piggybacking,” involves advancing the needle tangential to the chest wall into the lesion while using an adjacent rib for support. This approach can provide a safer trajectory and longer throw of the needle. ⁶⁸ Regional-specific complications include pneumothorax and damage to the underlying lung parenchyma/mediastinal structures. ⁶⁹ Additionally, care should be taken to not damage the neurovascular bundle which runs along the inferior-most aspect of each rib. ⁶⁹ Minor complication rates, such as postprocedural pain, of rib biopsy performed under CT guidance have been reported as 5.6% (minor complications) by Baffour et al with no reporting of major complications. ⁷⁰

Sternal biopsies, while rarely performed, can be especially challenging given the proximity to critical structures including the heart and great vessels. These biopsies are typically performed only when there is a single isolated lesion with no other available site to target. ⁷¹ While the approach angle for sternal lesions widely varies based on the exact location and characteristics of the target lesion, in general, a steep oblique angle that maximizes the core length is preferred. ⁷² Diagnostic complication rates of sternal biopsy have not been sufficiently studied. However, the diagnostic accuracy of sternal biopsy was reportedly low (64.7%) in a study by Song and Kwon. ⁷³

Upper Extremity

In the shoulder, an anterior approach ( Fig. 2 ) is preferred just lateral to the cephalic vein as this helps prevent denervation of the deltoid as the axillary nerve courses from posterior to anterior. ⁷⁴ Preservation of the deltoid is necessary for the reconstruction of the shoulder, as any iatrogenic damage can dramatically impact the patient's functional prognosis. ⁷¹ It is also important to avoid the long head of the biceps and the deltopectoral grove in an effort to decrease the likelihood of contamination of the main neurovascular bundle. ⁷⁴ An anterolateral approach is preferred for biopsy of the humerus with specific attention given to the cephalic vein positioned more laterally about the humerus and the spiral course of the radial nerve. ⁷¹ The arm should generally be externally rotated for lesions within the upper humerus and internally rotated for lesions within the mid humerus with again special attention to the location of the radial nerve and radial collateral artery. ⁷⁵ For lesions within the distal humerus, the arm can be positioned in either internal or external rotation and approached through the medial/lateral epicondyles as able ( Fig. 3 ). ^{71 75}

In the forearm, ulnar lesions should ideally be biopsied along the posteromedial superficial border unless the lesion is more distal in which a direct medial approach can be considered. ⁷⁴ Care should be taken to avoid the carpi ulnaris and first extensor compartment tendons. ⁷⁴ Approach to radial lesions can vary based on location ( Fig. 4 ), but a posterolateral approach is most often used. ⁷⁵ Furthermore, a more lateral approach should be considered when targeting a lesion in the distal radius. ⁷¹ Regional-specific structures to be aware of include the radial nerve and artery which is anterolateral to the radius and the medial nerve which is anteromedial to the proximal and mid radius. ⁷⁵ Care should be taken throughout the upper extremity to avoid contamination of multiple compartments by limiting the biopsy tract to the compartment in which the lesion is located as able. ⁷⁶ This includes not traversing the interosseous membrane which serves as a natural barrier preventing tumor spread. ⁷¹

Fig. 4.

( a ) Initial PA radiograph of a distal radial diaphysis lesion (arrow). ( b ) Initial axial CT of the distal radial diaphyseal lesion prior to biopsy. ( c ) CT-guided biopsy of the lesion using an anterior approach with the OnControl powered drill biopsy system.

Pelvis

Biopsy of pelvic lesions is typically performed using CT or US guidance. ⁴ Approach for pelvic lesions will vary based on the location. For lesions within the ilium or ischium bones, an anterior or posterior transosseous approach can be made to avoid pelvic surrounding structures. ⁷⁴ As with the extremities, care should be taken to avoid uncontaminated muscle compartments. ⁷⁵ Additionally, the posterior gluteal and anterior rectus femoris musculature should be avoided, as they are critical for the reconstruction and functional prognosis. ^{51 76} For lesions within the iliac wings, a transosseous approach ( Fig. 5 ) can be made to avoid surrounding structures, including the aforementioned musculature. ⁷⁶ Regional-specific complications include decreased functionality postsurgery, damage to the lumbosacral plexus or femoral neurovascular bundle, and damage to the regional structures within the pelvis. ⁷⁷ Complication rates are reported very rare, especially with regard to the biopsy of osseous lesions within the posterior pelvis. ⁷⁷

Fig. 5.

CT-guided biopsy of a lytic lesion within the iliac wing using a transosseous approach with the Bonopty coaxial system. A spring-loaded core biopsy needle was then inserted through the cannula and into a target lesion within the pubis.

Lower Extremity

For lesions throughout the femur, the rectus femoris, vastus intermedius, and quadriceps musculature should be avoided due to their importance for reconstruction. ^{4 51 76} The sciatic nerve, femoral neurovascular bundle, and profunda femoris artery should also be avoided. In the femoral head/neck, an inferolateral subtrochanteric transosseous approach ( Fig. 6 ) can be performed to help avoid contamination of the joint capsule. ⁷⁵ Care should be taken to avoid the greater trochanter bursa, as it is difficult to remove during surgery, and the transverse branch of the lateral circumflex femoral artery. ^{75 76} Within the proximal and mid-femur, a posterolateral approach just anterior to the lateral intermuscular septum is recommended to prevent penetration into other compartments. ⁷⁵ The needle can pass through a small portion of the vastus lateralis, as it can be resected without loss of function. ^{52 75} If necessary, a medial approach through the adductor longus can also be considered. ^{51 75} For lesions of the distal femur, a medial approach ( Fig. 7 ) through the vastus medialis or a lateral approach through the vastus lateralis is recommended. ^{52 75} The decision between which approach to take will depend on the location of the lesion and the expected surgical resection planning. ⁷⁵ Structures to avoid include the superficial neurovascular bundle, the popliteal neurovascular bundle in the popliteal fossa, and the medial and lateral geniculate arteries wrapping around the distal femur. Care should also be taken to avoid the suprapatellar recess when performing a biopsy of the distal femur as the joint could become seeded with a tumor. ⁷⁴

Fig. 6.

( a ) Initial axial CT of a heterogeneous sclerotic lesion within the femoral neck (arrow). ( b ) CT-guided biopsy of the lesion using an inferolateral subtrochanteric transosseous approach with the OnControl powered drill biopsy system.

Fig. 7.

CT-guided biopsy of a sclerotic lymphoma lesion within the distal femur using a medial approach with the OnControl powered drill biopsy system.

An anteromedial approach ( Fig. 8 ) is recommended for the tibia due to a minimal amount of overlying soft tissue. ⁷⁴ The anterior border of the tibia should be identified, and the needle inserted perpendicular to the tibial cortex to minimize needle slippage. The needle trajectory should avoid including the tibial tubercle, anterior/posterior tibia neurovascular bundles, peroneal neurovascular bundle, deep peroneal nerve, and peroneus brevis/longus muscles. ⁷⁵ As with the thigh, potential complications include cross-compartment seeding, especially considering there are four discrete compartments of the lower leg, as well as damage to neurovascular structures. ⁷⁶ Finally, the biopsy approaches for lesions within the fibula vary based on the location of the lesion. The main structure to avoid is the common peroneal nerve as it courses around the neck of the fibula. ⁷⁵

Fig. 8.

( a ) Initial oblique radiograph of a lytic lesion within the proximal tibial plateau (arrow). ( b ) Initial axial CT of the lesion prior to biopsy. ( c ) CT-guided biopsy of the lesion using a medial approach with a coaxial system.

General Complications

Beyond the aforementioned complications, needle breakage, although rare, is a potential complication that can result from angulation and bowing of the needle. ⁷⁸ In these cases, the stylet should be replaced if already removed and the orthopedic surgery team contacted for removal. ⁵¹ More general complications of bone biopsy include bleeding, infection, and pain which should be managed as clinically indicated. ⁷⁹ Finally, as with all procedures, there should be adequate preparation for a severe adverse event such as anaphylaxis.

Conclusion

As percutaneous image-guided biopsies have become a critical component of soft tissue and osseous lesion diagnosis, there is continuous development of new and innovative systems to increase efficacy and diagnostic accuracy. Image-guided percutaneous bone biopsies have become an essential and minimally invasive approach for the diagnosis of both malignant and nonmalignant bone lesions. As the role of radiologists in performing these procedures has expanded, their expertise in combination with the integration of MDT has enhanced the efficacy and safety of these procedures. Collaborative efforts between radiologists, pathologists, surgeons, and oncologists ensure comprehensive patient care while optimizing procedural outcomes. Advances in imaging technology and biopsy equipment further contribute to the high diagnostic value of bone biopsies. As personalized medicine continues to advance, the ability to perform histological and biomarker analysis will become an ever-increasing vital component of providing state-of-the-art care.