Interventional Spine

Jennifer, K, Sehn, BS
Louis, A, Gilula, MD, Non ASSR Member

Paper/Mentor

Purpose

Prior studies of the positive culture yield from image-guided percutaneous needle biopsies of spondylodiscitis lesions (1-6) have employed restrictive inclusion criteria that are not reflective of the broad population referred for biopsy in actual practice. Our aim is to evaluate the positive culture rate of image-guided percutaneous biopsy of sites of suspected spondylodiscitis in a series of 323 consecutive percutaneous needle biopsies that were sent for microbiologic cultures, as presented from a large group of referring physicians to one radiology biopsy service. The positive culture and diagnostic rate (utilizing culture alone or in combination with histopathology) will be assessed to facilitate interpretation of biopsy results in actual practice, considering the full breadth of patients referred for biopsy and culture.

Methods & Materials

All records of image-guided percutaneous biopsies of the spine performed by
musculoskeletal radiologists at one institution between January 2001 and March 2007
were identified. With approval from our institutional review board, the following
attributes were collected for each procedure (including those of patients with multiple
biopsies): age, sex, clinical and imaging history, level of biopsy, biopsy culture results,
pathology report, and clinical and imaging follow-up. Each record was categorized by degree of clinical suspicion for infection (high suspicion for infection, indeterminate suspicion for infection/tumor, or high suspicion for tumor). Clinical suspicion, cultures, and pathology were assessed and compared to previously published reports.

Results

We reviewed 323 consecutive percutaneous spinal biopsies. In 92 cases highly
suspicious for infection, 28 specimens yielded positive cultures (30.4%). Positive cultures resulted from 5 of 31 cases (16.1%) with intermediate suspicion (infection versus tumor). When suspicion for infection was low (i.e. suspicious for tumor), 10 of 200 cultures were positive (5.0%). From 113 cases sent to pathology with an intermediate or high suspicion, 63 were histopathologically diagnosed as infection (55.8%). Cultures were positive in 19 of those 63 cases (30.2%). Culture and/or pathology was positive in 73 (64.6%) of the 113 cases sent to pathology. There were no significant differences in rates of positive culture or pathology by vertebral region (p=0.51, p=0.81). The most frequently identified organisms were Staphylococcus aureus (13) and coagulase negative staphylococci (13).

Conclusion

Our results suggest that the positive culture rate of percutaneous spinal biopsy specimens is 30.4% with high suspicion for infection, 16.1% with indeterminate suspicion for infection/tumor, and 5.0% with high suspicion for tumor. Pathology was consistent with osteomyelitis in 55.8% of cases with indeterminate or high suspicion for infection. Cases suspicious for infection with pathologic confirmation had a positive culture rate of 30.2%, while culture and/or pathology were positive in 64.6% of the examined procedures.

References/Financial Disclosures

1. Jaramillo-de la Torre JJ, Bohinski RJ, Kuntz C 4th. Vertebral osteomyelitis. Neurosurg Clin N Am 2006;7:339-51.
2. Carragee EJ. Pyogenic vertebral osteomyelitis. J Bone Joint Surg Am 1997;79:874-80.
3. Patzakis MJ, Rao S, Wilkins J, et al. Analysis of 61 cases of vertebral osteomyelitis. Clin Orthop Relat Res 1991;264:178-83.
4. Tehranzadeh J, Tao C, Browning CA. Percutaneous needle biopsy of the spine. Acta Radiol 2007;48:860-8.
5. Hadjipavlou AG, Kontakis GM, Gaitanis JN, et al. Effectiveness and pitfalls of percutaneous transpedicle biopsy of the spine. Clin Orthop Relat Res 2003;411:54-60.
6. Chew FS, Kline MJ. Diagnostic yield of CT-guided percutaneous aspiration procedures in suspected spontaneous infectious diskitis. Radiology 2001;218:211-4.

The authors have no financial disclosures to make.