Needleless Ablation of Osteoid Osteoma and Osteoblastoma: The Emergent Role of MRgFUS

Round 1

Reviewer 1 Report

The review explains the technique of MR guided focussed US surgery for the benign bone forming tumours osteoid osteoma and osteoblastoma, having given background information about the tumours and current treatments. Although the technique has been available for some years and offers some advantages over current treatments, it is still quite rarely performed except in some centres and a review seems warranted.

Specific comments:

1. The entire manuscript should be critically read and edited by a native English speaker to correct numerous grammatical errors. In addition, both tumor and tumour are used; extreme care required with needleless and needless, for example.
2. Definitions: the distinction of OO from OB is based partly on size and various figures are given in the paper: the current WHO cut off is 2cm (OO < 2cm, OB > 2cm).
3. Factual content: the commonest location for OO is intracortical (which may have originally been subperiosteal), then intramedullary and the rarest location is said to be surface / subperiosteal. They are usually diaphyseal in long bones (i.e. not proximal femur and tibia); the mandible is a relatively rare location for OB (spine and long tubular bones commoner).
4. “Beyond standard TECHNIQUES” (unclear why the last word is in capitals) – see [1], this entire paragraph could do with revision.
5. Can the authors show a post treatment CT of the OB in fig 2?
6. End of p5: the authors talk of a small study of 6 non-spinal OO (ref 30) and then a larger trial of 29 cases – please provide a reference in an appropriate site in the text for this paper.
7. Similarly, p6, lines 224-234: the reference for this paper should appear before the very end of the paragraph, for example at line 226 after “…non-spinal OO.”
8. If ref 31 refers to the comparison of the 2 groups of 15 in the paragraph mentioned above, then a reference is needed for the retrospective study of 116 patients mentioned in the next paragraph (looks like 32, line 240?).
9. This study showed that strict anatomic location was required to guarantee a good result – the commoner sites of treatment failure would be worth mentioning.
10. Specific questions regarding the technique need to be answered more clearly. For example, is it ever possible to treat spinal lesions, or will depth and proximity to vital structures preclude this? A single (the final) sentence mentions spine OO. What is the maximum size of the lesion that can be successfully treated?
11. References: the first 5 are incompletely cited and there are numerous other errors in the reference list.

Author Response

1. We will provide an appropriate language revision.
2. Size will be corrected. 
3. Locations will be corrected.
4. "Beyond standard techniques" will be written in this way.
5. The patient was extremely young, that's why we have only a very early CT after treatment, in which bone sclerosis is still scarce, although patient was clinically fine.  
6. reference will be provided.
7. reference will be positioned in the correct point. 
8. reference will be provided.
9. Commoner sites will be added. 
10. Explanations will be provided. 
11. references will be corrected

Reviewer 2 Report

This review is generally well composed and clear in summarizing the usage of MRgFUS technique for treating OO and OB. It is indeed that there are much fewer documentation for OB than for OO with this technique. There are some minor suggestions and comments that need to be addressed prior to publication, as below:

In abstract and throughout the paper, when the authors define the size for OO <1.5cm or OB>1.5cm, they need to specify that they are "in diameter". Same as they mentioned the nidus sizes later.

Line 30: "HIFU" needs to be explained here to attract more broad audience. It is an abbreviation. Also, "VAS" needs an full annotation when first mentioned in Lin 219.

Line 36-37: citations needed.

Line 40: Is citation (5) correctly used here? I think it may be the citation (6), which should also be cited here in this sentence.  

Line 65-68: Need citations for this statement and a justification of why long-term medication therapy is not acceptable for young people.

Line 120-124: more citations need to be added in order to acknowledge the development of the MRgFUS in ablation of bone lesions.

Line 145-148: The last two sentences should belong to the next paragraph (Line: 148-154). Also, Citation 26 may be used in Line 148-154 plus some other citations.  The accessibility to the lesion is super important in determining how to use MRgFUS.

Line 155-157: Again, citations are needed for this section.

Line 164-166: If the lesion is very closed to the neurovascular structure, is it disqualified the usage of MRgFUS? Is there any other options or trick needed for the procedure to avoid the adjacent tissue damage? More details can be elaborated here, especially for the cases in Fig. 1 and 2.

Line 171: the brightness of Fig 1, especially for (d) needs to be enhanced.

Line 208-212: Are the 29 cases with 12-month follow-up studies published or not? If not, the studies need to be annotated.

Line 235-239: Is the 116 patient cohort study also included in citation 31? If not, it needs some annotations.

Line 248-249: Is there any cost benefit for using MRgFUS? This information could be useful for patients.

Author Response

In abstract and throughout the paper, when the authors define the size for OO <1.5cm or OB>1.5cm, they need to specify that they are "in diameter". Same as they mentioned the nidus sizes later.

"Diameter" will be added.

Line 30: "HIFU" needs to be explained here to attract more broad audience. It is an abbreviation. Also, "VAS" needs an full annotation when first mentioned in Lin 219.

HIFU and VAS will be explained.

Line 36-37: citations needed.

Citations will be provided.

Line 40: Is citation (5) correctly used here? I think it may be the citation (6), which should also be cited here in this sentence.  

An opportune correction will be done. 

Line 65-68: Need citations for this statement and a justification of why long-term medication therapy is not acceptable for young people.

Citations will be provided and an explanation will be provided.

Line 120-124: more citations need to be added in order to acknowledge the development of the MRgFUS in ablation of bone lesions.

Citations will be provided

Line 145-148: The last two sentences should belong to the next paragraph (Line: 148-154). Also, Citation 26 may be used in Line 148-154 plus some other citations.  The accessibility to the lesion is super important in determining how to use MRgFUS.

done

Line 155-157: Again, citations are needed for this section.

Citations will be provided

Line 164-166: If the lesion is very closed to the neurovascular structure, is it disqualified the usage of MRgFUS? Is there any other options or trick needed for the procedure to avoid the adjacent tissue damage? More details can be elaborated here, especially for the cases in Fig. 1 and 2.

More details will be given. 

Line 171: the brightness of Fig 1, especially for (d) needs to be enhanced.

done

Line 208-212: Are the 29 cases with 12-month follow-up studies published or not? If not, the studies need to be annotated.

done

Line 235-239: Is the 116 patient cohort study also included in citation 31? If not, it needs some annotations.

done

Line 248-249: Is there any cost benefit for using MRgFUS? This information could be useful for patients.

RESPONSE- It is not easy to give information about MRgFUS cost analysis, since in our National Health Service there are differences between regions in term of refunding for this procedure. Furthermore, there is still not an Healt Technology Assessment (HTA) for MRgFUS for treatment of benign bone tumors.