You are in: eMedicine Specialties > Radiology > MUSCULOSKELETAL Musculoskeletal Tumors, Percutaneous Needle BiopsyArticle Last Updated: May 18, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 10
  Author: Richard L Hallett, MD, Consulting Staff, Department of Radiology, Riverview Hospital Richard L Hallett is a member of the following medical societies: American College of Radiology, American Roentgen Ray Society, North American Society for Cardiac Imaging, Radiological Society of North America, Society for Cardiovascular Magnetic Resonance, and Society of Interventional Radiology Coauthor(s): J Mark Michael, MD, Consulting Staff, Section of Radiology, Columbus Regional Hospital Editors: Jacqueline C Hodge, MD, Assistant Professor, Department of Radiology, McGill University, Royal Victoria Hospital; Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand; William R Reinus, MD, MBA, FACR, Professor of Radiology, Temple University; Chief of Musculoskeletal and Trauma Radiology, Vice Chair, Department of Radiology, Temple University Hospital; Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute; Felix S Chew, MD, MBA, EdM, Professor, Department of Radiology, Vice Chairman for Radiology Informatics, Section Head of Musculoskeletal Radiology, University of Washington Author and Editor Disclosure Synonyms and related keywords: percutaneous biopsy of the musculoskeletal system, percutaneous musculoskeletal biopsy, percutaneous image-guided musculoskeletal biopsy, bone biopsy INTRODUCTIONSection 2 of 10
  Percutaneous, image-guided musculoskeletal biopsies provide an accurate, rapid, and cost-effective method for helping clinicians diagnose benign and malignant musculoskeletal lesions. In patients who present with nonspecific physical findings, imaging studies, and laboratory values, percutaneous biopsy can lead to a rapid and accurate diagnosis and allow implementation of the most appropriate therapy. Most biopsies can be performed using local anesthesia, with the addition of conscious sedation if necessary. Various imaging modalities can be used to target the lesion, including computed tomography (CT) scanning, fluoroscopy, ultrasound (US) scanning, and magnetic resonance imaging (MRI). The procedure is safe, with major complications uncommonly reported. When proper techniques are used, nondiagnostic or insufficient specimens are obtained in only approximately 8-10% of biopsies. Accuracy is expected to be 70-100% and is improved with expert cytopathologic interpretation. MORBIDITY AND MORTALITY ASSOCIATED WITH MUSCULOSKELETAL BIOPSYSection 3 of 10
The prevalence of complications associated with musculoskeletal biopsy is low and depends on the type of needle selected and on anatomic location. Reported incidence of complications ranges from 0-10%. Risk of significant complication should be less than 1% and is considered to be much less than the risk of an open surgical biopsy under general anesthesia. Complications may include the following:
LIMITATIONS AND CONTRAINDICATIONS IN MUSCULOSKELETAL BIOPSYSection 4 of 10
Limitations and/or contraindications for musculoskeletal biopsy are as follows:
TECHNICAL CONSIDERATIONSSection 5 of 10
Imaging modalities for guidance The choice of imaging guidance depends to some degree on operator preference. In general, biplane fluoroscopy can be used for superficial bony lesions, while CT scanning is preferred for deeper lesions and lesions in anatomically complex areas. US scanning obviates the need for ionizing radiation and can be used if an accompanying soft-tissue mass or cortical destruction is present. On rare occasions, MRI may be used to visualize lesions occult to CT scanning and to visualize the procedure in real time. However, MRI is of limited use in sclerotic lesions, in a relatively small number of interventional MRI systems, and with less cumulative operator experience. Biopsy needle Choice of needle systems is important. Sclerotic lesions require a trephine-type needle, such as the Ackerman or Craig needle (George Tiemann and Company, Long Island City, NY). These needles consist of an outer trocar, which remains fixed in the lesion and allows the removal of more material without the need for repositioning. The Ostycut needle (Angiomed/Bard Products, Karlsruhe, Germany) is a trephine-type needle with screw threads that allows easy advancement with a turning motion. A fine cutting needle, such as an 18-gauge spinal needle, an 18- to 22-gauge Chiba needle (Cook, Bloomington, IN), or a 20- to 22-gauge E-Z-EM needle (E-Z-EM Inc, Westbury, NY), can be passed in a coaxial fashion through the outer needle or trocar to obtain material for histopathology. An important consideration when choosing appropriate needle systems is the amount of tissue expected to be required for accurate pathologic diagnosis. The bore size of a biopsy needle is inversely related to gauge; thus, a smaller-gauge needle will yield a larger specimen for analysis. For example, an 11-gauge Craig needle will yield significantly more specimen per pass than will a 22-gauge Chiba needle. Therefore, the choice of needle should balance the need for a sufficient specimen with the increase in local complications that may result from the use of a larger-bore (smaller-gauge) needle. Some authors propose a complementary role for fine-needle aspiration biopsy and core biopsy, suggesting that both be performed during each biopsy procedure.4 The rationale behind this proposal is that there are instances when the specific diagnosis will be made by one technique and not the other, so that the overall accuracy of the procedure will be improved when both techniques are used. Hodge found aspiration-type needles to perform well in the diagnosis of malignant disease and infection, with the added benefit of smaller bore and no necessary skin incision.5 Hodge also found a complementary role for cytopathologic and histopathologic specimens, to increase diagnostic accuracy. Additionally, an algorithm has been proposed that could direct the choice of fine-needle aspiration or core biopsy based on imaging findings and preprocedural differential diagnosis. The final decision regarding the choice of fine-needle aspiration biopsy, core needle biopsy, or both should depend on the cytopathologic resources available and the expected lesion pathology. Biopsy route The choice of biopsy route is crucial to success.
Biopsy technique Many biopsies can be performed using only 1% lidocaine local anesthesia. For rib lesions, intercostal block can be performed using 0.25% bupivacaine. For deeper or painful lesions, conscious sedation with intravenous Versed (midazolam) or Valium (diazepam) and pain control with Demerol (meperidine) or Sublimaze (fentanyl) is used. The needle tract can be anesthetized using 1% lidocaine for added pain control during placement of the needle. The decision to proceed with percutaneous biopsy should be made after reviewing pertinent imaging studies and consulting with appropriate clinical staff, as well as on a case-by-case basis. For example, radionuclide bone scanning may be useful to delineate additional lesions that may be more easily accessible and pose less risk of biopsy-related complication. A fluorodeoxyglucose–positron emission tomography (FDG-PET) scan also may be appropriate, when there is clinical necessity to further depict (with CT or MR co-registration information) metabolically active portions of a lesion to guide needle placement. Care should be taken when selecting a lesion for biopsy to avoid biopsy at the site of a fracture. Specimen from a routine, nonmalignant fracture can appear similar microscopically to a sarcoma and present a significant diagnostic challenge to the pathologist. An exception is the vertebral body, where biopsy of a suspected pathologic fracture may be both appropriate and diagnostic. Additional considerations exist when planning pediatric musculoskeletal biopsy. As with adults, adequate sedation and pain control are required for patient comfort and safety. Frequently, intravenous sedation with pentobarbital (2-6 mg/kg) for children younger than 7 years and use of midazolam (0.05 mg/kg) for older children will achieve the desired effect. Fentanyl citrate (1-3 µg/kg IV) also may be used for pain control. Biopsy-site skin preparation with eutectic mixture of local anesthetic (EMLA) cream (a combination of lidocaine and prilocaine) and addition of sodium bicarbonate to the 1% lidocaine local anesthetic solution (to decrease pH and reduce stinging during administration) also are useful. General anesthesia will be required for procedures that are expected to be lengthy, complicated, or painful; for biopsy of anatomically elegant areas with little margin for patient motion; and for severely anxious and frightened patients. When possible, US scanning should be used for biopsy guidance to avoid ionizing radiation. IMAGING-SPECIFIC CONSIDERATIONSSection 6 of 10
Fluoroscopy Lesions should be superficial and visible by fluoroscopy. Biplane fluoroscopy is helpful in determining the placement of a needle directly into a lesion. For fluoroscopically visible superficial lesions, degree of confidence is high for obtaining an adequate position for the biopsy. Lesions that are not seen well in 2 planes should be approached using other appropriate imaging modalities. False-positive findings are uncommon and usually result from primary chondroid lesions. False-negative findings result from sampling error, small round-cell tumors, or chondroid lesions, such as chondrosarcoma diagnosed as enchondroma. Close follow-up studies must be performed in these patients. CT scanning Using CT scanning, lytic or blastic bone lesions with or without associated soft-tissue mass can be visualized. CT scanning provides a high degree of confidence. Biopsy can be performed on densely sclerotic lesions but may require a larger trephine-type needle. False-positive findings are unlikely in CT. False-negative findings are rare. In one study of 176 core biopsies and 45 fine-needle aspirations, accuracy for core biopsy was 93%, and for fine-needle aspiration, 80%. Only 8% of biopsies were nondiagnostic or insufficient6. MRI MRI guidance can be used if the lesion is not seen well on fluoroscopy or CT scan. MRI-compatible needles are available (E-Z-EM Inc; Somatex, Berlin, Germany; MDTech, Gainesville, FL). The needles may have higher nickel content in a low–magnetic-susceptibility alloy. Placing the frequency-encoding direction parallel to the needle path and the phase-encoding direction perpendicular to the path can reduce artifacts. Carbon-fiber needles have been developed that lack susceptibility artifacts but are almost invisible on MRI. Many newer MRI systems (eg, Magnetom Open, Siemens, Erlangen, Germany) have incorporated improved access for interactive interventional procedures. The units may include radiofrequency-shielded liquid crystal display screens for visualizing images, as well as foot-pedal control of image acquisition for the operator. Studies have shown time of procedure and incidence of complications to be the same or lower than those with CT- or US-guided procedures. MRI is exquisitely sensitive to marrow abnormalities even when CT scanning does not demonstrate a distinct abnormality. Therefore, MRI-guided biopsy provides the operator with a high degree of accuracy with which to target abnormal marrow. Ultrasound US guidance can be used to acquire specimens efficiently from a variety of soft-tissue tumors and processes. Advantages include real-time visualization of the needle's position and a lack of ionizing radiation. If biopsy of a soft-tissue malignancy is performed, consultation with the surgeon is necessary to ensure that the biopsy tract is removed during the surgical procedure. Both fine-needle and core needle biopsy specimens can be obtained using standard devices. US scanning can also be used to localize affected muscle groups and to guide biopsy of childhood neuromuscular diseases. US-guided biopsy of bone lesions can be performed when cortical destruction is present, acting as a window to allow passage of the needle into the medullary cavity. Biopsy of associated soft-tissue mass also is performed easily. OTHER PROBLEMS TO BE CONSIDEREDSection 7 of 10
Negative biopsy Tract seeding is rare, having been reported in less than 0.01% of patients undergoing abdominal biopsy. The occurrence rate can be expected to be similar for most bony lesions. An exception is primary bone sarcoma, in which the needle entry site should be marked on the skin in indelible ink so that the tract can be excised when the patient undergoes definitive surgery. Small round-cell tumors, such as spinal lymphoma and myeloma, are difficult to diagnose definitively, particularly in normal red-marrow–producing sites, such as the spine and pelvis. In one study, the use of larger-bore needles was suggested to increase the amount of recovered material, along with the use of frozen-section analysis or touch-preparation cytopathologic analysis to ensure that adequate material is obtained.6 The diagnostic yield for biopsy of sclerotic bone lesions is lower than that of lytic lesions; preprocedural knowledge of the possible need for additional samples is necessary when biopsy of a sclerotic lesion is undertaken.7 Review of all available pertinent imaging studies is again required, as these may disclose a concomitant lytic lesion for which fewer samples may be needed or disclose an additional lesion in which the biopsy route will pose less risk. When such a choice is available, biopsy of the lytic lesion is favorable to that of a similarly positioned sclerotic lesion. Imaging can direct the biopsy path away from these areas. Radionuclide bone scanning, FDG-PET scanning, CT scanning, and MRI all may be valuable to depict areas of low tracer uptake fluid attenuation/signal intensity and those lacking contrast enhancement, as seen with necrosis or mucinous/myxoid material. The modalities may also aid in appropriate biopsy path planning. Frozen-section and/or touch-preparation cytoanalysis should be performed. If biopsy results are not concordant with expectations, the needle should be redirected to sample additional areas of the lesion. These techniques can increase the accuracy rate 88-94% in this subset of patients. MEDICAL/LEGAL PITFALLSSection 8 of 10
Biopsy of the correct lesion is imperative for accurate and timely patient care. In one study, previously mentioned, biopsy was performed at an incorrect vertebral level in 1 of 94 patients.1 The patient did not have a reported complication; however, this case underscores the need for thorough review of preprocedural imaging studies. The authors in that case also recommended obtaining a visual CT scan or MRI of the lesion that is consistent with the suggested lesion prior to biopsy. MULTIMEDIASection 9 of 10
REFERENCESSection 10 of 10
Musculoskeletal Tumors, Percutaneous Needle Biopsy excerpt Article Last Updated: May 18, 2007 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
