Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors, 

I find the topic extremely interesting, especially because it brings together a more standardized approach for identifying and treating fascia-related low back pain. The protocol is described in a lot of detail, but I think some points need more clarification before publication.

1. Diagnostic criteria need stronger support
   The proposed diagnostic process is interesting, but many of the criteria seem to be based mainly on the authors’ clinical experience. The manuscript also says that sensitivity, specificity and inter-examiner reliability are not yet established. I think this limitation should be more visible throughout the paper, because some of the diagnostic steps are presented quite confidently.

2. Evidence for the treatment is still limited
   There is a lot of technical detail about the US-FHR procedure, but it is not fully clear how much clinical evidence is available for this technique in low back pain. There should be maybe a better separation of what is already supported by clinical studies and what is proposed based on their experience and anatomical reasoning.

3. How to distinguish fascia pain from other sources?
   This is probably one of the main points that needs clarification. Patients with low back pain can have several pain generators at the same time, and findings such as tenderness, ultrasound changes, or improvement after injection are not necessarily specific for fascia. It would be useful to explain more clearly how the clinician should decide that the fascia is actually the main source of the symptoms.

4. Safety of the deeper injection points
   Some of the proposed targets are located quite deep and close to important nerves, vessels, and other structures. The safety section is detailed, but I think more practical information would be helpful, especially regarding contraindications, possible complications, and the experience/training needed for clinicians using this protocol.

5. Future study should be described more clearly
   Since this paper is mainly a protocol and does not provide prospective clinical data, I would keep the conclusions a little more cautious. It would also help to give some more details about the planned validation study, especially how the authors will assess the reliability of the ultrasound findings, the diagnostic criteria, and the clinical effect of the treatment.

Overall, the paper is interesting and gives a detailed description of the proposed technique. My main concern is that the distinction between established evidence and the personal clinical experience is sometimes not clear enough. If this is clarified, I think the manuscript would be easier to evaluate and also more useful for future research.

Best regards.

Author Response

We thank the reviewer for the positive assessment and for the clear suggestions, which we found very helpful.

1. Diagnostic criteria need stronger support. We agree. The lack of validation is now stated at every place where the diagnostic process is presented: in the Abstract (Conclusions), in the legends of Tables 1 and 2 (an explicit "Caution" statement), in Step 8 (Section 4.3.10), in the new Limitations section (8.8) and in the Conclusions. Confident wording has been softened throughout (e.g., "standardized protocol" has been replaced by a protocol "based on our clinical experience", and "to standardize the technique" by "to describe in a reproducible form the technique"). In addition, the protocol no longer takes the JNOS fascial pain syndrome (FPS) criteria as its premise: the target population is now defined as low back pain in which a fascial component is suspected from the history, the physical findings and stacking fascia on ultrasound (Abstract, Sections 1, 2.2, 3, 4.1 and 9). The FPS framework is presented in Section 2.2 as the background from which the protocol developed, with its web source [2] and its published form as Box 7.23.1 of a textbook chapter [12], and its lack of external validation is stated as a limitation.

2. Evidence for the treatment. We have separated the evidence explicitly. The new Section 8.8 lists which components are supported by clinical or experimental studies (TLF nociceptive innervation; altered TLF thickness and shear mechanics in chronic LBP; non-inferiority of physiological solutions), which are based on anatomical reasoning (location of the release points), and which are based on our experience (bedside correspondences, referred-pain patterns, injection volumes, safety observations). We also state that the clinical effectiveness of US-FHR for LBP has not been established in controlled trials.

3. Distinguishing fascial pain from other sources. We have added a paragraph to Section 4.4 ("How the fascial component is judged to be the main source"). It states that no single finding is specific for fascia, and that the fascial component is regarded as predominant only provisionally, when palpation reproducing the familiar pain, stacking fascia directly beneath that point and compatible movement/loading findings converge at the same site; articular and neural sources are assessed in parallel with established tests, and an ultrasound finding without concordant tenderness is not treated as a pain source.

4. Safety of the deeper injection points. Section 5.2 now includes (i) contraindications, (ii) training requirements (deep points only after supervised training), (iii) adverse events in our experience, and (iv) published complication rates of analogous procedures (lumbar plexus block, paravertebral block, epidural injection) and evidence that ultrasound guidance reduces vascular puncture. The former POINT 12 (flavum–facet point) has been removed from the protocol (see Reviewer 2, comment 6).

5. Cautious conclusions and the planned validation study. The Conclusions have been rewritten in more cautious terms. The Limitations section (8.8) now ends with a brief statement that validation will proceed step by step through multicentre studies within JNOS, beginning with the inter-examiner agreement of the ultrasound finding and proceeding to controlled trials of the clinical effect, with independent validation by other groups welcomed. For the reviewer's information, the planned priorities are (i) the reliability of the ultrasound finding (two examiners scanning the same patient independently; kappa/ICC; quantitative ultrasound measures), (ii) the FPS criteria (inter-examiner reliability, and whether patients who meet them respond better to US-FHR than to a control procedure, i.e. testing the criteria against an external outcome), and (iii) the clinical effect (randomized, assessor-blinded comparisons with a control procedure, long-term follow-up and prospective adverse-event recording).

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

See attached file.

Comments for author File: Comments.pdf

Author Response

We thank the reviewer for the thorough and detailed review, which has substantially improved the manuscript.

1. Methodological framework. We agree that the protocol was not developed through a formal consensus process. Section 3 now states explicitly that the protocol is based on our clinical experience (an expert-experience-based protocol, in the reviewer's terms) and that no Delphi survey, expert panel or systematic review was used. Regarding SPIRIT: this checklist applies to protocols of prospective trials; because the present paper describes a clinical procedure and contains no trial, it was not applied, and the planned validation studies will be registered and reported according to the applicable guidelines (Sections 3 and 8.8). The word "standardized" has been removed from the Abstract and Conclusions.

2. Circularity of Step 8. We fully agree. Step 8 now states that improvement after injection is consistent with, but does not establish, involvement of the plane; and that, because it is judged by the treating clinician without blinding or a control, it is a therapeutic observation. For transparency, Section 2 and Step 8 now also state that the JNOS criteria use a marked response to precise intervention (relief of restricted range of motion and at least 75% pain relief) as the criterion standard for confirming FPS; Step 8 explains that this protocol follows the JNOS criteria in routine clinical practice, but that, because using the response as diagnostic confirmation in research would be circular, it is not used in that way in this paper and its validity remains to be tested in controlled studies. This is repeated as a limitation in Section 8.8.

3. Self-citation. US-FHR and the FPS framework were developed and proposed by our group, so at present much of the primary literature on them is inevitably our own. We have, however, (i) added an explicit statement (Sections 2.2 and 8.8) that the FPS framework originates from JNOS, with which we are affiliated, and has not been validated externally; (ii) reviewed all self-citations and removed those in the Conclusions that were not needed there; and (iii) added a description of US-FHR in an edited international reference textbook [12] together with independent safety literature [38–41]. Each remaining self-citation supports a distinct statement.

4. Aetiological claims. We have revised the language to be consistently conditional. In Section 2.5 the opening statement is now attributed to our experience, and the Fascial Memory Reset model is introduced as "a working hypothesis that has not yet been tested prospectively", with "may persist… may regress"; in Section 8.7 we "propose" that the FF point "may allow both to be released from a single site", as a research target; in Section 8.2 the shared rationale is described as "hypothesis-based"; and in Section 8.7 the premise is described as drawing on, "but is not demonstrated by", existing evidence.

5. Safety data. Section 5.2 now reports the adverse events in our experience. Roughly 360,000 US-FHR procedures were performed in our clinic (Kimura Pain Clinic) during the period covered by our previous video-archive study (October 2015–March 2026) [35]. No serious complications (pneumothorax, dural puncture, nerve injury or haematoma requiring treatment) have been encountered; minor events occur occasionally (transient injection-site soreness, and a vasovagal reaction with transient hypotension, mainly after head and neck procedures; both resolve shortly); because only saline or extracellular fluid is injected, local-anaesthetic toxicity and motor block do not arise. We state that these are clinical observations, not registry data. For POINTS 3, 6 and 7, and for the research target of Section 8.7, we now cite the risks of analogous procedures: serious complications including cardiac arrest after posterior lumbar plexus block [38], pneumothorax after paravertebral block [39] and dural puncture during epidural injection [40], with evidence that ultrasound guidance reduces vascular puncture [41].

6. POINT 12. On reflection, and on the advice of our co-authors, we chose option (a). The ligamentum flavum / flavum–facet (FF) point has been removed from the clinical protocol: Section 6.12 and its demonstration video have been deleted, the protocol now comprises fourteen points (Abstract, Sections 6 and 7, Table 2, Conclusions), and the former POINTs 13–15 are renumbered 12–14. The FF point is now described solely as a target for future research in Section 8.7 (paragraph "The FF point as a target for future research", with its anatomy, the approach under investigation, our clinical experience to date and the statements that it is not included in the protocol, that we perform it in our routine practice but do not recommend its adoption by other clinicians until prospective data are available, and that its safety and efficacy should be established in prospective studies by experienced physicians; Figures 29–31). Its technique, training requirements and safety data will be reported separately once prospective data are available.

7. Tables 1 and 2. An explicit "Caution" statement has been added to both legends: the findings and correspondences are based on our clinical experience, have not been validated for sensitivity, specificity or inter-examiner reliability, and are intended to narrow the examination, not to establish a diagnosis.

8. Reference [2] (JNOS). We acknowledge this in Section 2.2 and in the Limitations (Section 8.8): the FPS framework is a society proposal that has not been validated externally; it is published as a web resource [2] and, together with the US-FHR technique, as Box 7.23.1 of a chapter in an edited international reference textbook [12], which is now cited for both. As stated under Reviewer 1, comment 1, the protocol no longer takes the FPS criteria as its premise.

9. Terminology. A "Terminology" paragraph has been added to Section 2.2: "stacking fascia" is the ultrasound (morphological) finding; "densification" is the underlying tissue change described by Stecco and colleagues [11]; and FPS is the clinical classification. The text has been revised throughout to follow this hierarchy (e.g., Step 7 is now "Ultrasound confirmation of stacking fascia", and the release targets are described as planes "showing stacking fascia").

Figures and tables (rating "can be improved"). We checked all figures: every clinical image and illustration is supplied at high resolution with English labels, and the high-resolution files will be uploaded separately with the resubmission. The legends of Tables 1 and 2 have been revised as described above. Figure 1 (referred-pain diagram) has been replaced by a corrected version with twelve thoracic vertebrae and ribs; its anatomical base illustration was generated with Manus 1.6 (Manus AI) and the referral zones were drawn by hand, which is now declared in the caption, in Section 3 and in the Acknowledgments in accordance with the MDPI policy on generative AI. If the reviewer can indicate any specific figure or table that is unclear, we will be glad to improve it further.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Thickening of the thoracolumbar fascia is a major, nearly universal component of chronic nonspecific low back pain, which accounts for 90% of all cases of low back pain worldwide. The challenge lies in the fact that it is both a consequence and a cause of the pain. The initial adaptive response becomes a trigger for pain under specific conditions: age 40–60, high BMI, sedentary lifestyle, exposure to vibrations, kinesiophobia, and certain psychological factors (yellow flags). Hydrodissection is a symptomatic treatment that does not address the underlying cause of the thickening. It is important to emphasize the role of a “therapeutic window” lasting a few weeks to allow the patient to immediately resume active physical therapy, strengthening exercises, and stretching without pain. It is this restored range of motion that will prevent the fascia from thickening again.

This text reads more like a chapter from a book than a report on experimental research. The anatomical accuracy of the 15 areas to be treated is excellent, and the illustrations are remarkable.

The initial results from the past two years are encouraging, but we lack long-term data on the fasciae and on the optimal use of this therapeutic window.

While these points were addressed in the discussion, they should also be included in the abstract. Hydrodissection can break the vicious cycle, but it should never be used as a stand-alone treatment.

Author Response

We thank the reviewer for the kind remarks on the anatomical accuracy and the illustrations, and for the important clinical point.

We agree that US-FHR addresses the symptom and not all of the factors that maintain fascial thickening, and that it should never be used as a stand-alone treatment. We have added this to the Abstract (Conclusions), to the Discussion (Section 8.1, "Place of US-FHR within multimodal care") and to the Conclusions. In our practice the period of pain relief is used to resume active movement—patients are encouraged to walk and to perform radio taiso, a standardized calisthenics routine widely practised in Japan, and are referred for exercise therapy where appropriate. We also state that the optimal duration of this therapeutic window, and whether restored movement prevents recurrence, have not been studied (Section 8.1), that long-term outcome data are lacking (Section 8.8), and that the planned studies will include long-term follow-up (Section 8.8).

Regarding the comment that the text reads like a book chapter: as a clinical protocol, the paper deliberately provides detailed, point-by-point technical description. We have, however, added an explicit Methods framework (Section 3), a Limitations section (8.8) with the validation plan so that the paper can be evaluated as a research report.

Sincerely,
Hiroaki Kimura, on behalf of all authors

Author Response File: Author Response.pdf