Abstract
Dear Sir We appreciate the interest in as well as the comments on our paper (1) by Dr Ferrante and agree with his explanation; however, at no point in our paper did we indicate that the C1-2 area was the exact leakage site. In fact, our interpretation of the heavily T2-weighted MR myelography results was consistent with his, and our treatment as discussed in the paper was to apply epidural blood patches at the C5-6 level, which we had determined was the likely origin site of the leakage. That treatment was highly successful in this patient. In short, we did not misinterpret the imaging results. Therefore, we suggest that CSF leakage along the nerve root sleeves is more likely to be the true leakage than that at C1-2 retrospinal space.
The term ‘CSF leakage’ as used in our paper was broadly indicative of collections of CSF that had leaked out but not always at the exact ongoing leakage site(s). In a non-medical sense, it is like saying there is an oil leak when one sees motor oil on the ground underneath where a car was parked. However, we do agree that ‘CSF collection’ would have been a better term to avoid such misunderstandings, and perhaps some discussion is needed in the professional community to standardize the exact meanings of the terms CSF collection vs. CSF leakage. Please note that the purpose of the paper which Dr Ferrante comments on was to describe and document a case of spontaneous intracranial hypotension associated with isolated cortical venous thrombosis and subarachnoid haemorrhage, a case the like of which had, to the best of our knowledge and research, never been reported. It was not about heavily T2-weighted MR myelography or about interpreting imaging data; however, we have published a paper (2) describing the technique and findings. We also have another paper in press (3) and we invite readers to consult those reports, which discuss MR myelography results and their interpretations in depth.