CT-guided fine-needle aspiration in vertebral osteomyelitis: true usefulness of a common practice

Abstract

Computed tomography (CT)-guided biopsy of the spine is considered a safe, accurate, and relatively inexpensive examination technique. Our purpose was to determine the diagnostic accuracy of CT-guided biopsies exclusively for vertebral osteomyelitis. A retrospective study was performed from a consecutive series of 72 patients with confirmed vertebral osteomyelitis with 46 CT-guided biopsies performed in 40 patients. Biopsy specimens were sent for bacteriologic and cytologic analysis. An adequate specimen for microbiologic examination was not obtained in one case and not enough sample for additional pathologic examination in 17 cases. The mean age of patients was 58 years, with a range of 1-88 years, including 24 men and 16 women. The level of spinal biopsy was thoracic in 18 (40%) and lumbar in 28 (60%). The analysis revealed the infection agent in 20 cases (43% sensitivity). Diagnostic rates obtained in patients with previous antibiotic treatment were significantly lower (23% vs. 60%, p = 0.013). Computed tomography-guided fine-needle aspiration biopsy is an important tool in the diagnostic evaluation of vertebral osteomyelitis. However, this technique yields a lower diagnostic rate than previously reported biopsy of neoplastic vertebral lesions, especially if performed in patients with previous antibiotic treatment.

Computed tomography–guided percutaneous biopsy for vertebral osteomyelitis: a department's experience

“…(6/12) prior to the use of antibiotics and in only 25% (2/8) after antibiotic initiation; Grados, in 80% of those not treated with antibiotics but only in 48% of those treated with antibiotics; and de Lucas, in 60% before and only 23% after antibiotic treatment. 10,13,21 However, our comparison of the expected microbiology results from those patients who did not receive antibiotics prior to the percutaneous biopsy (9/44 or 20.5%) with the observed results from patients who received antibiotics prophylactically (7/40 or 17.5%) indicated that the results were similar for both groups and that the difference was not statistically significant (p = 0.4748). In other words, the proportion of positive cultures to those biopsied was low for both patients receiving and not receiving antibiotics prior to the biopsy, a finding in contrast to what has been previously reported.…”

“…In addition, these series frequently described a relatively lower sensitivity in the subgroup of inflammatory cases rather than tumor cases." 10 It is already known that the role of image-guided biopsy in diagnosing malignant conditions is well established-89 of 116 samples (76.7%) collected in our trial when there was an initial concern for neoplastic process were diagnostic-but its role in diagnosing infectious diseases is less accurate.…”

Staphylococcus aureus Infections: Epidemiology, Pathophysiology, Clinical Manifestations, and Management

“…Where possible, the biopsy specimen is best obtained prior to antibiotic treatment. Several investigators have found that the microbiological yield from biopsy specimens of patients on antibiotics is ϳ50% lower than that from biopsy specimens obtained prior to antibiotic treatment (440)(441)(442). Where an initial percutaneous biopsy specimen is negative, there may be value in obtaining a second percutaneous biopsy specimen.…”

Surgical treatment of spondylodiscitis. An update

“…Since biopsy after antibiotic treatment may end in a negative culture [13,15], antibiotic suppression prior to the biopsy should be the rule. However this is a controverted issue as nearly 40% of spondylodiscitis without prior antibiotic treatment may present a negative culture [20].…”