Cardiovasc Intervent Radiol (2013) 36:880–882 DOI 10.1007/s00270-012-0422-0
LETTER TO THE EDITOR
Percutaneous CT-Guided Biopsy of C3 Vertebral Body: Modified Approach for an Old Procedure Uei Pua • Stephen Yung-Wei Chan
Received: 10 March 2012 / Accepted: 29 April 2012 / Published online: 22 May 2012 Ó Springer Science+Business Media, LLC and the Cardiovascular and Interventional Radiological Society of Europe (CIRSE) 2012
Abstract Percutaneous biopsy of upper cervical vertebrae is challenging due to the various critical structures in the location and often requires difficult trajectory such as transoral or paramaxillary approaches. The purpose of this manuscript is to illustrate the utility of head rotation in creating a potential space for direct percutaneous access to C3 vertebral body for safe biopsy. Keywords
Imaging Biopsy Spine/nervous system
Computed tomography (CT)-guided biopsy of the cervical spine is a useful, minimally invasive technique to obtain tissue for histological diagnosis and has been used since the 1990s [1]. Biopsies of the cervical vertebrae are challenging compared to their thoracic or lumbar counterparts as a result of the presence of various structures in the neck (e.g., carotid sheath, thyroid gland, upper aerodigestive tracts). Upper or suprahyoid cervical vertebrae levels (C1–C3) are considerably more difficult than lower cervical vertebral levels, and biopsies of the suprahyoid cervical vertebrae are often performed via paramaxillary or transoral approaches [2–5]. Here we illustrate an approach that
U. Pua (&) Department of Diagnostic Radiology, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore e-mail:
[email protected] S. Y.-W. Chan Department of Anaesthesiology, Intensive Care and Pain Medicine, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore
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uses contralateral head rotation to displace the carotid sheath and create a safe and simple trajectory for a direct lateral approach to the C3 vertebral body for percutaneous biopsy. A 45-year-old woman with a history of psoriatic arthropathy sought care for increasing neck pain of 1 month’s duration with no neurological symptoms. Magnetic resonance imaging (MRI) of the neck revealed mild prevertebral soft tissue swelling with enhancement and bone marrow edema of C3 vertebra with adjacent end-plate erosion (Fig. 1). Possible considerations included nonbacterial osteitis associated with psoriasis or osteomyelitis. Because the patient was receiving immunosuppressive therapy (methotrexate) for her psoriasis, biopsy of C3 vertebra was needed for histological and microbiological assessment to exclude an infective cause. The procedure was performed under CT fluoroscopic guidance. The patient was placed supine positioned with her head in left lateral rotation of 90° and the forehead taped to the head support for stability (Fig. 2A). Under sterile condition and CT fluoroscopy, a 14-gauge Bonopty biopsy set (AprioMed AB, Sweden) was used via a direct lateral approach to access C3 vertebral body (Fig. 2B). With contralateral rotation of the neck, the carotid sheath was greatly displaced anteriorly and medially. This creates a large posterior space between the carotid sheath and the vertebral artery (Fig. 2A). The needle trajectory transgressed the sternocleidomastoid muscle posterior to the carotid sheath and anterior to the vertebral artery (Fig. 2B, C). Two cores of tissue were obtained and sent for histological and microbiological analysis. Each specimen was [1.5 cm long, as per our institutional practice for histopathologic and microbiologic studies for vertebral bodies. The procedure was performed with local anesthesia and intravenous analgesia (75 mg fentanyl). The patient was
U. Pua, S. Y.-W. Chan: Percutaneous CT-Guided Biopsy of C3 Vertebral Body
Fig. 1 A Contrast-enhanced sagittal T1-weighted MRI of the cervical spine revealing enhancement of C3 vertebral body (arrow) with thickening of the overlying prevertebral fascia. B Contrast-enhanced axial T1-weighted MRI of C3 vertebra (asterisk) at the level indicated by arrow in (A). Trajectory for percutaneous biopsy can be perceived as difficult because of the position of the carotid sheath (straight arrows), the vertebral artery (curved arrows), and the aerodigestive tract (A)
discharged well after 4 h of monitoring. Microbiological growth was negative, and histology revealed necrotic tissue with inflammatory changes. The patient was treated as for nonbacterial osteitis, and methotrexate therapy was reinitiated. The presence of critical structures in the suprahyoid neck precludes direct percutaneous access to the upper cervical vertebrae. Even common techniques used in the
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lower cervical spine, such as anterolateral access with medial displacement of the carotid sheath via either manual displacement or hydrodissection, or a direct anterior approach with laryngeal subluxation [6], may not be possible, in part as a result of convergence of the critical structures (vascular and aerodigestive structures) into a narrow crosssection at the base of the skull. Although the posterolateral approach is often feasible to perform a biopsy of posterior elements, a transpedicular approach to access the anterior elements in the upper cervical vertebrae is often not possible, and if it is attempted, it requires extreme caution as a result of the small size of pedicles and the adjacent vertebral artery running within the foramen transversarium [1, 2]. The transoral route is therefore considered the gold standard offered as the first-line option in many centers. Nevertheless, the need for general anesthesia for airway control, availability of expertise, and patient acceptance are relevant drawbacks. The approach we describe here displaces the carotid sheath anteromedially by positioning the patient’s head in contralateral rotation. This creates a potential space posterior to the carotid sheath for safe needle trajectory. Furthermore, as a result of the anterolateral entry angle to the vertebral body, this approach enables access to the entire width of the vertebral body along the longest axis of the bone (Fig. 2C), and it also allows the collection of a long biopsy specimen with a single pass. This in comparison to the perpendicular or near perpendicular trajectory with transoral or anterolateral approaches, respectively, where the length of the biopsy specimen is limited by the short anteroposterior dimension of the vertebral body. The principle of this technique is based on the anatomy of the carotid sheath, which together with the pretracheal fascia is firmly attached anteriorly to the deep surface of sternocleidomastoid muscle, while posteriorly it is not attached to the prevertebral fascia but is free to slide over it. Therefore, by contralateral head rotation, the excursion of the sternocleidomastoid, which is maximal at the base of skull, would bring the carotid sheath anterior and medially, away from the needle trajectory at the C2 and C3 level. Quite often, assessment of suitability for percutaneous biopsy in this anatomical region is decided on the basis of the perceived anatomic layout and the hurdles presented on axial CT or MRI, with the patient imaged in neutral position during the diagnostic study (Fig. 1B). We therefore urge clinicians to keep in mind the significant excursion of the carotid sheath with head rotation (Figs. 1B vs. 2A) and consider the possibility of using this safe and easy approach when performing upper cervical spine intervention. The exact utility of this approach compared to conventional transoral approach would benefit from future comparative studies.
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U. Pua, S. Y.-W. Chan: Percutaneous CT-Guided Biopsy of C3 Vertebral Body b Fig. 2 A Contrast-enhanced axial CT image over C3 vertebra body
with the patient in left lateral head rotation. The carotid sheath (straight arrow) is significantly displaced anteriorly and medially (compare with Fig. 1A), creating a potential space (double arrowhead) between the carotid space and the vertebral artery (curved arrow). B CT fluoroscopic image capture of the penetration needle of the Bonopty set transgressing the potential space to directly engage the anterolateral aspect of the vertebral body. C CT fluoroscopic image capture revealing the biopsy cannula within the vertebra body. This approach allowed the biopsy specimen to be retrieved along the longest axis of the vertebral body
Conflict of interest of interest.
The authors declare that they have no conflict
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