Response to the Letter to the Editor Concerning “Management of Aggressive Vertebral Haemangioma and Assessment of Differentiating Pointers Between Aggressive Vertebral Haemangioma and Metastases-A Systematic Review” by Subramaniam et al.

Dear Editor,

We would like to thank you for the opportunity to respond to the concerns raised in the letter and to clarify aspects of our interpretation in relation to these concerns. We would also like to thank the authors for their interest in our paper and for taking the time to express their concerns.

CONCERN 1: We agree the fact that Pain Intensity – Numeric Rating Scale (PI-NRS) used by Narayana et al. ¹ is different when compared to the Visual Analog Scale (VAS). PI-NRS and VAS are the 2 most widely used pain assessment tools and the popularity of both scales sometimes causes VAS to be mistaken as NRS and vice versa, however, there remain high correlations between both tools as stated.^2,3 With regards to the values presented, Narayana et al. has clearly mentioned the mean preop score of 8.5 in the article but for mean post-op follow-up at 6 months – a clear numerical value is not stated. The authors states that among the 14 patients, 8 patients had complete relief of pain (score 0) and 6 patients had significant relief of pain (score 1-3). Hence, post op follow-up mean numerical value cannot become .7 as stated in the letter to the editor and we do agree there is round off numerical error (1.7 instead 1.8, total score of 6 patients 11, 11/6) in our attempt to report the mean of scores of those 6 patients who had significant relief of pain. However, we authors have highlighted that 57.1% (8/14) patients have become pain-free (score 0) at 6 months following percutaneous vertebroplasty. Although there is round off numerical error we authors strongly feel that our interpretations and content of figure 2 are upheld.

CONCERN 2: In AVH - surgery is associated with massive haemorrhage.^4,5 The pragmatic approach of treatment in dealing with such scenario is preop embolization, anterior corpectomy reconstruction and posterior instrumentation. ⁶ Nair et al. ⁷ (paper 16 in our reference) is the only article which qualified to be included in above mentioned section of our review, as they have clearly stated the improvement in neurology following surgery as per Frankel grading - the main criteria for the article to be included in the review.

The author’s clearly states that they have attempted pre-op embolization in their institute initially for 2 cases of AVH but found it difficult and unsuccessful as the vertebral bodies were collapsed and converted into solid mass. Considering the impact of neuraxial compression, the authors felt unwise to subject the patient to multiple treatment modalities, and hence direct surgery was adopted in the reported series. However they do emphasize clearly in their conclusion that pre-operative embolization followed by surgery is an option. Hence it is sceptical to include the article as preop embolisation before surgery category or not. We authors have mentioned the article as anterior corpectomy + posterior instrumentation in Table 4 (row 4). However, to have uniformity while assessing the modes of treatment (in the discussion, Table 5, Figure 4 and Figure 6), we have included it in the category of preop embolisation + Anterior corpectomy, reconstruction and posterior stabilisation.

CONCERN 3: Nair et al. ⁷ in their article results section mention blood loss in the range of 1.5-3 L (page 3 line 6) and in discussion section mention that they encountered bleeding in the range between 1.5 and 2.5 L in all their patients (page no. 4, line no. 1). We only have a range with lower and upper limit and though there were 7 samples we don’t know the values of all. Therefore we assume there were only those 2 samples and calculate the average of those 2. In our case would be either 2 (if we take range of 1.5-2.5 L) or 2.25 (if we take range of 1.5-3 L) and so we have 2 calculated average for given ranges and we settled for the average of those 2 averages which is 2.1. Hence to compare the blood loss, we have used a mean value of 2100 mL, we authors fully agree that it may not be statistically correct and the calculated average/mean will be correct if the underlying distribution is symmetric. However, we know the average/mid-range we are interested in would lie between the average of the lower and upper limits of the range interval.

CONCERN 4: We authors accept the fact the paper Prabhuraj et al. ⁸ should have been categorized as per-operative glue embolization and not perioperative glue embolization in Table 4 (Row 6). A typo error which we authors regret not to have corrected during proof reading of the article.

CONCERN 5: All the included study images been acknowledged and Figure 9 has been cited in the manuscript under the Discussion part – vide 10th paragraph, second line.

We the authors have done the systematic review regarding management of AVH, a rare clinical entity where the literature is confusing with many treatment options and our review attempt to provide clinical insight into the optimal line of management. We categorically have suggested the treatment options could be based on the presence of neurological symptoms or not. Patients of AVH presenting with severe back pain refractory to medical treatment will benefit from less invasive percutaneous vertebroplasty and patients of AVH with associated neurological symptoms will benefit from less morbid posterior approach surgery (Vertebroplasty, decompression with posterior instrumentation) – Management principles which has been highlighted in the first paragraph of our Discussion section in the article. Recurrence following less invasive posterior approach surgery or AVH presenting with neurological symptoms and bony component impinging the cord can be considered for more morbid -anterior approach surgery with prior embolization. We have also emphasized in the end of our article to consider the treatment principles (Grade practice recommendation Ref. [9]) as C (Optional). All the pooled articles were prospective and retrospective in nature with no randomized control trial suggesting to carry out the above principles in a blind-fold manner. The treating specialist should execute their clinical expertise, judgement and the above management principles judiciously in a balanced way to treat this clinical ailment.