Use of the Vascularized Fascial Flap Based on the 1,2 ICSRA Artery for Scapholunate Ligament Repair: An Anatomic Study

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

General Comments

This manuscript presents an anatomical cadaveric feasibility study assessing the potential use of a vascularized fascial flap based on the 1,2 intercompartmental supraretinacular artery (1,2 ICSRA) for augmentation of scapholunate ligament repair. The topic is clinically relevant, and the concept of biological augmentation using pedicled vascularized tissue is timely. The study is clearly framed as a technical note/anatomical feasibility assessment rather than a biomechanical or clinical outcome investigation.

Overall, the manuscript is well written and structured, but several methodological clarifications and changes in interpretation are required before the work can be considered suitable for publication.

Materials and Methods

The Materials and Methods section adequately describes specimen preparation, surgical exposure, flap identification, elevation technique, and measurement procedures. However, several methodological aspects require improvement:

1. Sample size justification is missing. While cadaveric feasibility studies commonly involve small samples, a rationale for the choice of five specimens should be provided.
2. Interobserver measurement reliability is not reported. Measurements were performed by two independent operators, but no assessment of agreement or variability is presented. Including at least basic reliability data (e.g., ICC or TEM) would strengthen methodological rigor.
3. Lack of quantitative feasibility criteria. Feasibility is described qualitatively; objective benchmarks (e.g., minimum pedicle length thresholds or angular limitations) would enhance reproducibility and applicability.

Discussion

The Discussion section provides a solid anatomical and clinical background and appropriately contextualizes the proposed technique within existing scapholunate ligament reconstruction approaches. The manuscript correctly emphasizes the limitations of purely mechanical reconstructions and highlights the novelty of combining structural and biological augmentation.

Areas requiring improvement:

1. Overinterpretation of clinical implications. As this is a purely cadaveric feasibility study with no biomechanical or in vivo testing, statements implying clinical benefit or faster healing should be more cautiously phrased. These should be framed as hypotheses rather than expected outcomes.
2. Limited comparative discussion. The Discussion should more explicitly compare this method with other biological or vascularized techniques reported in the literature, emphasizing potential advantages or drawbacks.
3. Future research direction could be clearer. While the need for biomechanical testing and clinical trials is mentioned, outlining specific next steps (e.g., animal models, pilot clinical cohorts) would strengthen the translational perspective.

 

Limitations

The authors acknowledge some important limitations, including the small number of specimens and the absence of biomechanical testing. This is commendable; however, the Limitations section could be expanded and formalized:

Additional limitations that should be explicitly addressed include:

• Absence of interobserver reliability data for measured flap dimensions.
• Cadaveric tissue quality, which cannot simulate in vivo vascular dynamics or tissue pliability.
• Lack of fixation testing, since no anchors were available; therefore, the true technical feasibility of ligament integration remains uncertain.
• No comparative anatomical control group, limiting the ability to judge relative mechanical advantage or arc of rotation versus alternative techniques.

Addressing these issues candidly would enhance transparency and scientific rigor.

Conclusions

The conclusions appropriately state that the technique is anatomically feasible, which is supported by the presented data. However, any clinical extrapolation should be tempered and strictly limited to suggestions for future investigation. Phrases implying effectiveness or healing enhancement should be reframed to reflect that such benefits remain speculative until supported by in vivo or biomechanical evidence.

Author Response

Dear Reviewer,

We would like to sincerely thank you for your thoughtful comments and suggestions regarding our manuscript. We have carefully considered each point and revised the manuscript accordingly. Our responses are outlined below:

Sample size justification is missing. While cadaveric feasibility studies commonly involve small samples, a rationale for the choice of five specimens should be provided.

Response (from line 58 to 63): 

The sample size was determined by the organizational setting of the anatomical dissection course, in which one upper limb was assigned to each pair of participants (for a total of seven upper limbs). Of these, only five specimens were suitable for inclusion, as the remaining limbs were anatomically compromised by previous surgical approaches and therefore excluded from analysis.  

Interobserver measurement reliability is not reported. Measurements were performed by two independent operators, but no assessment of agreement or variability is presented. Including at least basic reliability data (e.g., ICC or TEM) would strengthen methodological rigor.

Response (from line 129 to 138):

Interobserver reliability was assessed for pedicle length, graft width, and graft length measurements using the intraclass correlation coefficient (ICC, two-way random effects model, absolute agreement). For all three parameters, measurements obtained by the two independent observers were identical across all specimens, resulting in an ICC of 1.00 for pedicle length, graft width, and graft length. These findings indicate perfect agreement between observers for all anatomical measurements evaluated in this study. While perfect ICC values may appear unusual, they accurately reflect the absence of measurement discrepancies in this dataset and should be interpreted in the context of the limited sample size. Future studies with larger cohorts and repeated measurements may provide a more granular estimate of measurement variability.

Lack of quantitative feasibility criteria. Feasibility is described qualitatively; objective benchmarks (e.g., minimum pedicle length thresholds or angular limitations) would enhance reproducibility and applicability.

Response (from line 97 to 101): For the purpose of this study, feasibility was defined using quantitative anatomical criteria. A minimum pedicle length of 14 mm was required to allow safe reach of the implantation site, and feasibility further depended on the ability to achieve at least 110° of pedicle rotation without excessive tension in order to properly orient the graft toward the recipient site.  

Overinterpretation of clinical implications. As this is a purely cadaveric feasibility study with no biomechanical or in vivo testing, statements implying clinical benefit or faster healing should be more cautiously phrased. These should be framed as hypotheses rather than expected outcomes.

Response 1 (from line 104 to 109): The small number of specimens limits the generalizability of the findings, and no biomechanical testing was performed to compare the strength of the reconstructed ligament with that of the native or non-augmented repair. Therefore, the present results should be interpreted as preliminary anatomical observations that may serve as a basis for future biomechanical and clinical investigations   Response 2 (from line 180 to 185): The purpose of the present study is to explore the anatomical feasibility of a vascularized fascial flap as a potential augmentation option, rather than to demonstrate clinical effectiveness. The proposed technique is based on the hypothesis that combining mechanical support with vascularized tissue may, in theory, create a more favorable biological environment for healing.   Response 3 (from line 192 to 194):These findings confirm anatomical feasibility and define the vascular anatomy and potential arc of rotation of the flap, but do not provide evidence of functional or clinical ben efit.   Response 4 (from line 214 to 215):These properties suggest a possible “like-with-like” reconstruction, although their clinical relevance remains to be demonstrated.  

Limited comparative discussion. The Discussion should more explicitly compare this method with other biological or vascularized techniques reported in the literature, emphasizing potential advantages or drawbacks.

Response (from line 194 to 180):Local augmentation techniques previously described in the literature include the use of the dorsal intercarpal ligament, three-ligament tenodesis, composite grafts (such as the bone–retinaculum–bone technique), and many others[9-11]. In the former, local augmentation is obtained from the dorsal intercarpal ligament, which is partially incised to create a ligamentous flap that is then used to stabilize the scaphoid and lunate, typically fixed to the lunate through transosseous sutures. An alternative technique is the three-ligament tenodesis (3LT), which uses a distally based strip of the flexor carpi radialis tendon passed through a scaphoid tunnel, fixed to the lunate via a dorsal trough and anchor suture, tensioned through the dorsal radiotriquetral ligament, and temporarily stabilized with K-wires across the scapholunate and scaphocapitate joints. The bone–retinaculum–bone technique, on the other hand, involves excision of a longitudinal portion of Lister’s tubercle in order to harvest a segment of bone covered by retinaculum; after removal of the central bony portion with a rongeur, a composite graft is obtained that can be interposed between the scaphoid and lunate. To date, no technique involving a vascularized flap for scapholunate ligament augmentation has been described, and existing approaches primarily focus on restoring anatomical continuity and structural stability, with limited consideration of biological or vascular support.

Future research direction could be clearer. While the need for biomechanical testing and clinical trials is mentioned, outlining specific next steps (e.g., animal models, pilot clinical cohorts) would strengthen the translational perspective.

Response: To translate these anatomical findings into potential clinical applications, the next steps could include biomechanical testing in cadaveric wrist models to quantify the contribution of the flap to scapholunate stability, followed by pilot studies in appropriate animal models to assess in vivo vascular reliability, tissue integration, and healing potential. If successful, small-scale pilot clinical cohorts could then be considered to evaluate safety, technical feasibility, and preliminary functional outcomes.

 

• Absence of interobserver reliability data for measured flap dimensions. Interobserver reliability has been added (line 129 to 138).”

   

• Cadaveric tissue quality, which cannot simulate in vivo vascular dynamics or tissue pliability.
• Lack of fixation testing, since no anchors were available; therefore, the true technical feasibility of ligament integration remains uncertain.
• No comparative anatomical control group, limiting the ability to judge relative mechanical advantage or arc of rotation versus alternative techniques.

Response(from line 220 to 228): 

While cadaveric models are appropriate for anatomical feasibility studies, they cannot fully reproduce in vivo conditions, particularly with regard to vascular dynamics, tissue elasticity, and biological healing responses. Biomechanical testing was not performed, and fixation testing could not be carried out because suture anchors were not available. Consequently, the mechanical contribution of the flap and the strength of ligament integration under physiological loads could not be quantitatively assessed and remain to be clarified in future studies. Finally, the absence of a comparative anatomical control group precludes direct comparison with alternative reconstructive techniques.

However, any clinical extrapolation should be tempered and strictly limited to suggestions for future investigation. Phrases implying effectiveness or healing enhancement should be reframed to reflect that such benefits remain speculative until supported by in vivo or biomechanical evidence.   Response 1 (from line 224 to 226) : Consequently, the mechanical contribution of the flap and the strength of ligament integration under physiological loads could not be quantitatively assessed and remain to be clarified in future studies.   Response 2 (From line 251 to 261):  Consequently, the mechanical contribution of the flap and the strength of ligament integration under physiological loads could not be quantitatively assessed and remain to be clarified in future studies.

 

   

Reviewer 2 Report

Comments and Suggestions for Authors

The paper presents an anatomical feasibility study describing the application of a vascularized fascial flap derived from the 1,2 intercompartmental supraretinacular artery (1,2 ICSRA) as a prospective biological enhancement for scapholunate ligament repair.  The rationale is clinically pertinent and addresses a known limitation of scapholunate ligament surgery associated with the restricted vascular supply to the ligament and adjacent structures.

 In hand surgery, the proposed technique uses a local pedicled flap with a vascular anatomy that is well characterized.  The cadaveric dissections show that the 1,2 ICSRA follows a consistent path, that the flap dimensions are correct, and that the arc of rotation is big enough to reach the scapholunate gap without causing any tension or damage to blood vessels under normal anatomical settings.  The authors correctly characterize the study as a cadaveric examination and confine their conclusions to anatomical feasibility.

 In general, the publication fulfills the scope of a Technical Note and gives anatomical information that could be helpful for future biomechanical or clinical research.

 Minor comments

1.  While the anatomical viability of the suggested flap is sufficiently illustrated, a concise elaboration of the surgical approach would enhance the practical reproducibility of the Technical Note.  A brief explanation of how the fascial flap should be positioned after it is moved into the scapholunate interval, as well as a short description of how it will be fixed in place in vivo (for example, sutures to capsular or ligament remnants, with or without anchors), would help readers understand how the flap could be used in a standard scapholunate repair.
2.  In the Materials and Methods section, it would be good to explain how the length of the pedicle was measured and characterized.  It would be clearer if you said if this measurement is for the distance from the start of the 1,2 intercompartmental supraretinacular artery to the pivot point or to the base of the flap.
3.  Making small changes to the style could make it even easier to read.  A little less repetition in the Discussion and making sure that terms and abbreviations are used the same way throughout the article would make the text flow better without changing what it says.

Author Response

Dear Reviewer,

We would like to sincerely thank you for your thoughtful comments and suggestions regarding our manuscript. We have carefully considered each point and revised the manuscript accordingly. Our responses are outlined below:

A brief explanation of how the fascial flap should be positioned after it is moved into the scapholunate interval, as well as a short description of how it will be fixed in place in vivo (for example, sutures to capsular or ligament remnants, with or without anchors), would help readers understand how the flap could be used in a standard scapholunate repair.

Response (from line 73 to 86): 

After performing a capsulotomy to adequately expose the scapholunate interval and completing a standard scapholunate repair, the vascularized fascial flap was mobilized on its 1,2 intercompartmental supraretinacular artery pedicle and gently rotated toward the dorsal scapholunate interval.The flap would be positioned as an onlay augmentation over the repaired ligament, with the synovialized surface oriented toward the joint to minimize friction and promote biological integration. Fixation of the flap in vivo would be performed as an adjunct to the primary ligament repair and would be intended to maintain intimate contact between the fascial graft and the scapholunate ligament remnants. This could be achieved using absorbable sutures placed between the margins of the flap and the residual ligament tissue when adequate remnants are present. In cases in which sufficient ligamentous tissue is not available for secure suturing, suture anchors placed in the dorsal aspect of the scaphoid and lunate could be considered to achieve stable fixation, although this was not evaluated in the present cadaveric study.  

It would be clearer if you said if this measurement is for the distance from the start of the 1,2 intercompartmental supraretinacular artery to the pivot point or to the base of the flap.

Response (from line 92 to 95): 

Flap length and width referred exclusively to the fascial graft component, excluding the vascular pedicle. Pedicle length was defined as the distance from the proximal origin of the 1,2 intercompartmental supraretinacular artery to the distal end of the vascular pedicle at the base of the flap.  

Making small changes to the style could make it even easier to read.  A little less repetition in the Discussion and making sure that terms and abbreviations are used the same way throughout the article would make the text flow better without changing what it says.

Thank you for the suggestion. Repetitive sentences have been removed throughout the manuscript, improving the overall readability and flow of the text.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have addressed all reviewer comments and implemented the requested revisions. The revised version of the manuscript can be accepted for publication.