title: Role of Percutaneous Image Guided Biopsy in Spinal Lesions: Adequacy and Correlation with MRI Findings.
abstract: BACKGROUND
  Although, MRI has increased our understanding of spinal pathologies, accurate diagnosis of spinal lesions need biopsy, so that early treatment can be initiated.
  
  
  OBJECTIVE
  To evaluate the accuracy of biopsy, safety and yield of percutaneously done image guided spinal biopsy using a large bore needle and correlate between MRI findings and biopsy as well as the importance of various MRI findings in establishing the diagnosis.
  
  
  METHODS
  All spinal lesions after clinical and MRI evaluation were subjected to Jamshidi Needle biopsy using 11 gauge needles. Biopsy material was sent for culture/sensitivity, AFB smear and histopathological examination. The outcome assessment included percentage of patients in whom diagnosis was changed after biopsy, yield in biopsy and complications of biopsy. MRI findings, biopsy findings and final diagnosis were correlated to know the sensitivity and specificity of MRI and biopsy diagnosis. Logistic regression analysis was used to study the importance of each of MRI findings in making a diagnosis.
  
  
  RESULTS
  Forty five patients with spinal lesions underwent biopsy using an 11 gauge Jamshidi needle. Initial biopsy was inconclusive in 4 patients giving a positive yield in about 91.2% of cases and a repeat biopsy ensured conclusive report in all cases. Following biopsy there was a change in diagnosis in 8% cases. MRI showed sensitivity of 85.71% and specificity of 93.54% for the diagnosis of malignancy and sensitivity of 85.71% and specificity of 86.48% for the diagnosis of tuberculosis. In contrast, initial biopsy had sensitivity of 92.85% and specificity of 100% for the diagnosis of malignancy and sensitivity of 71.42% and specificity of 100 % for the diagnosis of infection. Logistic regression analysis showed good correlation between malignancy and posterior bugle in the vertebral body in the absence of a fracture (p = 0.007), involvement of pedicles and posterior elements (p = 0.001) and soft tissue extension (p = 0.002); there was good correlation between infection and epidural abscess (p<0.001) as well as paradiscal involvement (p<0.001).
  
  
  CONCLUSIONS
  Image guided biopsy done with good technique helps in accuracy of diagnosis thus ensuring the correct treatment at the earliest and has minimal complications. This study also shows that presence of epidural abscess and paradiscal involvement in MRI are highly suggestive of infection, while pedicle involvement and posterior bulge of vertebral body before the onset of pathological fracture are suggestive of malignancy, but all spinal lesions should be biopsied to confirm the diagnosis.
authors.affiliation: Associate Professor, Department of Orthopedics, Kasturba Medical College, Mangalore, Manipal University , Karnataka, India .
authors.forename: Janardhana P
authors.initials: JP
authors.lastname: Aithala
keywords: Image guided biopsy; Percutaneous biopsy; Spine pathology