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Comprehensive Analysis of Profunda Artery Perforator Flap Thickness Based on CTA

International Microsurgery Journal. 2019;3(3):2
DOI: 10.24983/scitemed.imj.2019.00120
Article Type: Original Article

Abstract

Introduction: The anterolateral and anteromedial thigh (ALT and AMT) flaps are the most commonly used thigh free flaps for intraoral reconstruction. Recently, the profunda artery perforator (PAP) flap has been proposed as an alternative. This study aimed to compare the thickness of these thigh flaps and to identify the factors influencing flap thickness in our population.
Methods: The study sample comprised legs (n = 72) of patients who underwent head and neck reconstruction with a fibula free flap. Preoperative computed tomographic angiography was used for morphologic analysis. Pearson correlation analysis was used to assess the relationship between flap thickness and different continuous variables. A repeated measures mixed linear model analysis was performed using all the available measurements. The adjusted marginal means of each flap were estimated using a fixed-effect model.
Results: Flap thickness was more in women (p < 0.001) and was correlated with body mass index (BMI). The R2 coefficients for ALT, AMT, and PAP were 0.64, 0.69, and 0.48, respectively (p < 0.01). ALT thickness (1.61 ± 0.07 cm) was significantly lower than AMT thickness (2.05 ± 0.08 cm, p < 0.0001). PAP thickness was significantly higher than the thickness of the ALT/AMT flaps when the measurement was made over the first perforator of the adductor magnus (2.31 ± 0.12 cm, p < 0.0001), but there was no significant difference when the measurement was made over the second perforator (1.88 ± 0.09 cm, p > 0.05).
Conclusions: Thigh flaps tend to be thicker in women and in those patients with high BMI. The thigh flap that is least influenced by BMI is the PAP flap. The PAP flap harvested around the second perforator of the adductor magnus can be as thin as the ALT flap.

Keywords

  • Anterolateral thigh; anteromedial thigh; computed tomographic angiography; perforator flap; profunda artery

Introduction

Soft tissue microsurgical reconstruction in the head and neck regions can be performed with different types of free flaps. For decades, the anterolateral and anteromedial thigh regions have been considered as the ideal donor sites [1,2], especially in Asian countries. Recently, the profunda artery perforator (PAP) flap harvested from the posteromedial region of the thigh has been proposed as a good choice for use in oral cavity reconstruction [3,4,5]. However, in the Western countries, thigh flaps, especially the PAP flaps, are not used as often as in the Asian countries for oral reconstruction because there are concerns regarding the greater thickness of thigh flaps as compared with the radial forearm free flaps (RFFF).

There are previous publications on anterolateral thigh (ALT) flap thickness measured with Doppler ultrasound [6,7] and only one study using computed tomographic angiography (CTA) [8]. However, none of these studies compare ALT flap thickness with PAP flap thickness in the same patient. 

The aim of this study was to compare the PAP flap thickness with the thickness of other thigh flaps that were more commonly used for intraoral reconstruction and to identify the factors influencing its thickness in our population using CTA. This information would be useful to facilitate flap selection based on desired tissue volume in patients with greater thigh thickness, like our population.

Material and Methods

Study Sample
The study sample comprised 72 legs of 36 patients. The inclusion criteria were the patients who underwent head and neck microsurgical reconstruction with a fibula free flap and a preoperative CTA. The exclusion criteria consisted of the antecedent of previous thigh flap harvested. CTA was performed on a 64-slice multiple detector computed tomography scanner (LightSpeed VCT; GE Healthcare, Milwaukee, WI, USA) using a standardized protocol. Data post-processing was done using the open-source software HorosTM v 1.1.7 (GNU Lesser General Public License, version 3). 

Morphologic analysis of flap thickness and perforator location was done for the ALT flap, the anteromedial (AMT) flap, the distal superficial femoral artery perforator (d-SFAP) flap, and the PAP flap in all 72 legs. The d-SFAP flap is not commonly used for intraoral reconstruction, but it was also included in this study because of the constancy of the location of its perforator. For the ALT flap, the references were the anterior superior iliac spine (ASIS) and the superolateral border of the patella. The best perforator around the midpoint between both references was identified and its location relative to the ASIS was registered. The same references were used for the AMT flap. The cutaneous perforator of the AMT flap was located close to the intersection between the rectus femoris and sartorius muscles. The perforator’s location (relative to the ASIS) and its origin—whether arising from the lateral circumflex femoral artery (LCFA), medial circumflex femoral artery (MCFA), or superficial femoral artery (SFA) — were identified. For the PAP flap, the references were the ischial tuberosity and the superomedial border of the patella. The first and second perforators of the adductor magnus were registered. So, two PAP flaps were considered in each leg: one PAP flap based on the first proximal perforator of the adductor magnus (PAP1) and another PAP flap based on the second or distal perforator (PAP2). The d-SFAP flap was based on a direct cutaneous branch of the SFA. The references used to locate this branch were the pubic tubercle and the superomedial border of the patella (Figure 1).

To allow comparisons between the patients with different thigh lengths, longitudinal measures were expressed as a percentage of the total length between the reference points for each flap. Flap thickness was measured at the point where the cutaneous perforator entered the deep fascia (Figure 2).
 

Figure 1. Example of measurements from proximal reference points to the perforators. ALT, anterolateral thigh; AMT, anteromedial thigh; d-SFAP, distal superficial femoral artery perforator; PAP1, profunda artery perforator flap based on the first perforator of the adductor magnus; PAP2, profunda artery perforator flap based on the second perforator of the adductor magnus.

 

Figure 2. Axial CTA images: perforators of different thigh flaps. Thickness was measured at the point where the cutaneous perforator entered the deep fascia. The arrow indicates the anteromedial thigh perforator; the # indicates the anterolateral thigh perforator; the star indicates the profunda artery perforator; the cross indicates the distal superficial femoral artery perforator. AM, adductor magnus; G, graciligs; RF, rectus femoris; S, Sartorius; Saf, saphenous vein; VL, vastus lateralis; VM, vastus medialis.


Statistical Analysis
Statistical analysis was done using R v 3.1.1. (CRAN, Vienna). Normality was assessed using the Kolmogorov-Smirnov test and by visual inspection of the shape of histograms. The independent samples t-test was used to test the statistical differences between the means of the two given groups, as in the comparison of flap thickness in men and women. Pearson correlation analysis was used to assess the relationship between flap thickness and different continuous variables. A repeated-measures mixed linear model analysis was performed using all the available measurements of the total thickness (36 subjects, 72 legs, 360 flaps). The type of flap (ALT, AMT, d-SFAP, PAP1, PAP2) and side (left or right) were included in the model as repeated measures factors. The most appropriate covariance structure for the residuals (repeated covariance type) was a first-order autoregressive structure with heterogeneous variances. Parameters were estimated using the maximum likelihood method. A fixed-effect model was built and the marginal means of each flap were estimated, taking into consideration of the covariates such as sex, body mass index (BMI), and the relative distance from the proximal reference point to the point where the thickness of each flap was measured (longitudinal measures were expressed as a percentage of the total length between the reference points for each flap). Bonferroni adjustment was used for multiple comparisons. The threshold for significance was set up to 0.05.

Results

In this sample of 36 patients, reconstruction was necessary because of oral carcinoma (25 patients), ameloblastoma (5 patients), trauma sequelae (3 patients), or radionecrosis (3 patients). Basic descriptive statistics are summarized in Table 1 and individual data are shown in Table 2.

The best identifiable perforator of the ALT flap was located about 21.8 ± 2.57 cm (mean ± standard error) from the ASIS (50.1% of the total length between the references). A reliable perforator for the AMT flap located around the intersection between the rectus femoris and sartorius muscles was present in 52/72 legs (72.3%); the origin of the perforator was from the LCFA in 38/72 legs (52.8%), from the SFA in 10/72 legs (13.9%), and from the MCFA in 4/72 legs (5.6%). In 20/72 legs (27.7%), the best perforator for the AMT arose very distally from the SFA (far from the intersection between the rectus femoris and sartorius muscles). The perforator of the d-SFAP was located about 20.5 ± 3.17 cm from the pubic tubercle (57% of the total length between the references). The first and second perforators of the adductor magnus muscle were located about 8 ± 1.88 cm and 10.84 ± 2.32 cm, respectively, from the ischial tuberosity (26% and 35% of the total length between the references).

For each kind of flap, the thickness was significantly higher in women (p < 0.001) (Table 3). Thickness was also correlated with BMI. The R2 coefficients for ALT, AMT, d-SFAP, and PAP were 0.64, 0.69, 0.62, and 0.48, respectively (p < 0.01). 

ANOVA showed significant differences between the thicknesses of the four kinds of thigh flaps (Figure 3). ALT thickness (1.61 ± 0.07 cm) was significantly lower than AMT thickness (2.05 ± 0.08 cm) and d-SFAP thickness (2.8 ± 0.09 cm, p < 0.0001). The thickness of the PAP flap was significantly higher than that of the ALT flap when the measurement was made over the first perforator (2.31 ± 0.12 cm, p < 0.0001), but it was not significantly different from the ALT/AMT flaps when the measurement was made over the second perforator (1.88 ± 0.09 cm, p > 0.05)
 

 

 

 

Figure 3. Graph illustrates the differences in thickness measured in the location of the perforator artery of each flap in a single patient. Estimated marginal means of flap thickness were adjusted using the following covariates: relative distance from proximal reference at mean 43.1, BMI at mean 26.7, and sex using a repeated-measures mixed linear model analysis (n = 36, F = 69.264; p < 0.001; -2 log likelihood = 473.217). The table below the graph shows the results of the post-hoc tests with Bonferroni adjustment for multiple comparisons. ALT, anterolateral thigh; AMT, anteromedial thigh; BMI, Body mass index (kg/m2); d-SFAP, distal superficial femoral artery perforator; n.s, not significant; PAP1, profunda artery perforator flap based on the first perforator of the adductor magnus; PAP2, profunda artery perforator flap based on the second perforator of the adductor magnus.

Discussion

Intraoral reconstruction can be performed using different types of thigh flaps. Flap thickness is an important factor to be considered during flap selection. In this paper, we present our anthropomorphic analysis of different thigh flaps in a Spanish population. 

The locations of the best identifiable perforators for the ALT flap in our sample are similar to those described in the previous reports [1]. For the AMT flap, the most common origin of the perforator found at the intersection between the rectus femoris and sartorius muscles was the LCFA, which was similar to the previous reports [9]. Mojallalal et al. [10] have described the constancy of the location of the d-SFAP flap perforator at a mean distance of 22.79 ± 1.55 cm from the pubic tubercle and in close relation with the saphenous vein, which is comparable to the mean distance of 20.5 ± 3.17 cm in our study. Our data are also consistent with other studies that have found most of the perforators of the PAP flap located 8-10 cm from the pubic crease [3]. 

Previous researchers have used ultrasonography to evaluate the thickness of the ALT free flap. In 2002, Nakayama et al. [6] performed an ultrasonography study of living head and neck cancer patients and reported the mean thickness of skin and subcutaneous tissue of the ALT flap in their population as 7.1 ± 3.4 mm. Aladimi et al. [7] reported a mean thickness of 14.5 ± 4.2 mm for the ALT flap; this relatively high value was probably because the volunteers in their study were all healthy and Americans. Hsu et al. [8] reported a lower mean thickness of 9.8 ± 4 mm in 202 healthy volunteers from Taiwan. These data from Doppler ultrasound studies suggest that the flap thickness varies with ethnic origin and health status and it appears to be less in Asian patients than in Westerners.

There was only one previous study using CTA to assess flap thickness and it was performed in a Western population (106 patients) to assess only the ALT flap [11]. The mean thickness of ALT flaps in men and women in that study were 9.9 and 19.9 mm, respectively, which were comparable with our findings. However, there were no previous publications to assess flap thickness with CTA on other thigh flaps.

Similar to our study, earlier studies have also demonstrated thicker subcutaneous fat in the anterior thigh region in female patients than in male patients [8,11,12,13], and also the ALT flap thickness has been correlated with BMI [8,11,13,14]. In the present study, we have demonstrated for the first time that there exists a correlation between flap thickness and BMI and gender in all thigh flaps studied, including the PAP flap. Moreover, the PAP flap appears to be the least correlated with BMI. 

In addition, the difference in thickness of subcutaneous fat between upper and lower parts of the anterior thigh has been reported [12,13]. Nevertheless, to date, there has not been any anthropomorphic analysis of the thickness of PAP as compared to the thickness of ALT or AMT free flaps in the same patient.

The PAP flap has become an ideal choice for autologous tissue breast reconstruction as an alternative to the deep inferior epigastric perforator flap [15]. However, there are few reports regarding its use for intraoral reconstruction [3,4,5]. The main concern in our population could be its greater thickness compared to the ALT flap, but with our results, we can show that there is not much difference when the PAP flap is designed around a distal perforator. Our current results may encourage the decision for harvesting a PAP flap as an alternative to an ALT flap when the indication is made for intraoral reconstruction.

In our study, the population included oncological patients. Nutritional status of these patients could be influencing our final results. Nevertheless, one of the most common reasons for microsurgical reconstruction of the head and neck in an adult patient is head and neck carcinoma. However, future research on correlating nutritional status with skin thickness will be useful in order to clarify the differences between series with healthy and/or head and neck cancer patients.

Conclusion

All thigh flaps, including the PAP flap, tend to be thicker in women and in those patients with high BMI. The thigh flap that is least correlated with BMI is the PAP flap. Besides, the PAP flap thickness is not significantly different from that of the ALT/AMT flaps when the measurement is made over the second perforator of the adductor magnus muscle. Hence, harvesting the PAP flap around a distal perforator makes it easier to obtain a flap as thin as the ALT flap used in the same patient. Because of the similarity in thickness, the PAP flap can be considered in our population to be a good alternative of the ALT flap for intraoral reconstruction.

References

  1. Wei FC, Jain V, Celik N, Chen HC, Chuang DC, Lin CH. Have we found an ideal soft-tissue flap? An experience with 672 anterolateral thigh flaps. Plast Reconstr Surg 2002;109:2219-2226. [View Article]
  2. Cheng HT, Tian JY, Hsu YC, Chen HH, Chang SC. Use of the ipsilateral anteromedial thigh flap for immediate rescue of nonviable anterolateral thigh flaps in head and neck cancer reconstruction. J Craniofac Surg 2017;28(6):e517-e521. [View Article]
  3. Scaglioni MF, Kuo YR, Yang JC, Chen YC. The posteromedial thigh flap for head and neck reconstruction. Plast Reconstr Surg 2015;136(2):363-375. [View Article]
  4. Wu JC, Huang JJ, Tsao CK, Abdelrahman M, Kolios G, Cheng MH. Comparison of posteromedial thigh profunda artery perforator flap and anterolateral thigh perforator flap for head and neck reconstruction. Plast Reconstr Surg 2016;137(1):257-266. [View Article]
  5. Fernández-Riera R, Hung SY, Wu JC, Tsao CK. Free profunda femoris artery perforator flap as a first-line choice of reconstruction for partial glossectomy defects. Head Neck 2017;39(4):737-743. [View Article]
  6. Nakayama B, Hyodo I, Hasegawa Y, et al. Role of the anterolateral thigh flap in head and neck reconstruction: advantages of moderate skin and subcutaneous thickness. J Reconstr Microsurg 2002;18(3):141-145. [View Article]
  7. Aladimi MT, Han B, Li C, Helal H, Gao Z, Li L. Factors to consider when deciding on the type of free-flap reconstruction of head and neck soft tissue defects. ORL J Otorhinolaryngol Relat Spec 2017;79(4):230-238. [View Article]
  8. Hsu KC, Tsai WH, Ting SP, Hsueh JH, Chen LW, Lin YS. Comparison between anterolateral thigh, radial forearm, and peroneal artery flap donor site thickness in Asian patients-a sonographic study. Microsurgery 2017;37(6):655-660. [View Article]
  9. Cigna E, Chen HC, Ozkan O, Sorvillo V, Maruccia M, Ribuffo D. The anteromedial thigh free flap anatomy: a clinical, anatomical, and cadaveric study. Plast Reconstr Surg 2014;133 (2):420-429. [View Article]
  10. Mojallal A, Boucher F, Shipkov H, Saint-Cyr M, Braye F. Superficial femoral artery perforator flap: anatomical study of a new flap and clinical cases. Plast Reconstr Surg 2014;133(4):934-944. [View Article]
  11. Seth R, Manz RM, Dahan IJ, et al. Comprehensive analysis of the anterolateral thigh flap vascular anatomy. Arch Facial Plast Surg 2011;13(5):347-354. [View Article]
  12. Gong ZJ, Wu HJ. Measurement for subcutaneous fat and clinical applied anatomic studies on perforators in the anterior thigh region. J Oral Maxillofac Surg 2013;71(5):951-959. [View Article]
  13. Yu P. Characteristics of the anterolateral thigh flap in a Western population and its application in head and neck reconstruction. Head Neck 2004;26(9):759-769. [View Article]
  14. Hakim SG, Jacobsen HC, Trenkle T, Sieg P, Wieker H. Impact of body mass index, gender, and smoking on thickness of free soft tissue flaps used for orofacial reconstruction. J Craniomaxillofac Surg 2015;43(8):1325-1329. [View Article]
  15. Haddock NT, Gassman A, Cho MJ, Teotia SS. 101 Consecutive profunda artery perforator flaps in breast reconstruction: lessons learned with our early experience. Plast Reconstr Surg 2017;140:229-239. [View Article]

Editorial Information

Publication History

Received date: March 26, 2019
Accepted date: September 02, 2019
Published date: November 25, 2019

Ethics Approval and Consent to Participate

This study adhered to the principles of the Declaration of Helsinki in terms of medical protocols and ethics and was approved by the institutional ethics committee (Reference number 3965) from the Reina Sofia University Hospital, Córdoba, Spain.

Funding

The study did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Conflict of Interest

The authors report no financial or other conflict of interest relevant to this article, which is the intellectual property of the authors.

Disclosures

Partial content of this manuscript was presented at the 24th Congress of the European Association for Cranio Maxillo Facial Surgery, 18-21 September 2018, Munich, Germany under the title of “Thigh Free Flap Thickness in Western Population: Customizing Free Flaps for Tongue Reconstruction”.

Copyright

© 2019 The Authors. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CC-BY).

UGC de Cirugía Maxilofacial, Hospital Universitario Reina Sofía, Córdoba, Spain
UGC de Cirugía Maxilofacial, Hospital Universitario Reina Sofía, Córdoba, Spain
UGC de Cirugía Maxilofacial, Hospital Universitario Reina Sofía, Córdoba, Spain
UGC de Cirugía Maxilofacial, Hospital Universitario Reina Sofía, Córdoba, Spain
UGC de Neurocirugía, Hospital Universitario Reina Sofía, Córdoba, Spain
UGC de Cirugía Maxilofacial, Hospital Universitario Reina Sofía, Córdoba, Spain

Address: Hospital Universitario Reina Sofía, Periodista Quesada Chacón 8-2-1ºA, 14005, Córdoba, Spain
Table 1.JPGDescriptive statistics of sex, age and BMI.

Table 2.JPGDetail of flap thickness in individual patients.

Table 3.JPGThigh flaps thicknesses.

Figure 1.JPG
Figure 1. Example of measurements from proximal reference points to the perforators. ALT, anterolateral thigh; AMT, anteromedial thigh; d-SFAP, distal superficial femoral artery perforator; PAP1, profunda artery perforator flap based on the first perforator of the adductor magnus; PAP2, profunda artery perforator flap based on the second perforator of the adductor magnus.
Figure 2.JPG
Figure 2. Axial CTA images: perforators of different thigh flaps. Thickness was measured at the point where the cutaneous perforator entered the deep fascia. The arrow indicates the anteromedial thigh perforator; the # indicates the anterolateral thigh perforator; the star indicates the profunda artery perforator; the cross indicates the distal superficial femoral artery perforator. AM, adductor magnus; G, graciligs; RF, rectus femoris; S, Sartorius; Saf, saphenous vein; VL, vastus lateralis; VM, vastus medialis.
Figure 3.JPG
Figure 3. Graph illustrates the differences in thickness measured in the location of the perforator artery of each flap in a single patient. Estimated marginal means of flap thickness were adjusted using the following covariates: relative distance from proximal reference at mean 43.1, BMI at mean 26.7, and sex using a repeated-measures mixed linear model analysis (n = 36, F = 69.264; p < 0.001; -2 log likelihood = 473.217). The table below the graph shows the results of the post-hoc tests with Bonferroni adjustment for multiple comparisons. ALT, anterolateral thigh; AMT, anteromedial thigh; BMI, Body mass index (kg/m2); d-SFAP, distal superficial femoral artery perforator; n.s, not significant; PAP1, profunda artery perforator flap based on the first perforator of the adductor magnus; PAP2, profunda artery perforator flap based on the second perforator of the adductor magnus.

Reviewer 1 Comments

  1. This article summarizes the thickness of different kinds of thigh flaps in the relation to CT angiographic findings. There are some shortcomings in the article. First, this is the study comprising of statistical analyses of the different type of flaps, but we are not provided with any table which gives us the details of thickness of these flaps in individual patients, reviewers cannot analyze these results themselves. Only the results of the data are given. This issue may question the authenticity of the study.
    ResponseA table with individual data was included in the revised manuscript (Table 1).
     
  2. The final interpretation of the study. That the PAP flap tends to be thicker in woman and those with high BMI is already well established. It is also well established that if we harvest flap based on a distal perforator it will always be thinner than harvesting on proximal one. The uniqueness of the study needs to be clarified.
    ResponseThe uniqueness of the study is summarized. This the first study using Computed Tomographic Angiography to assess thickness of thigh flaps other than the anterolateral thigh flap. To date, there have not been any anthropomorphic analysis of the thickness of PAP, as compared to the thickness of ALT or AMT free flaps, in the same patient. This is the first report describing mean thickness of the PAP flap around both the first and second perforators of the adductor magnus muscle in a western population. We also report that the PAP flap appears to be the least correlated with BMI in our population.
     
  3. Also detailed data is required to conclude that PAP flap is least influenced by BMI.
    ResponseThe correlation coefficient (R2) is a measure of how strong of a linear relationship there is between two given variables. These values are explicitly described in the text. Flap thickness is correlated with BMI in all kind of thigh flaps that we studied. The R2 coefficients for ALT, AMT, d-SFAP, and PAP were 0.64, 0.69, 0.62, and 0.48, respectively (p < 0.01). The R2 coefficient for PAP is the smallest, so it has the weakest correlation.

Reviewer 2 Comments

  1. This article may not bring further new information to the already present literature. The authors only proposed their interpretation without giving details. The detailed data of all the patients should be provided to facilitate the analysis.
    ResponseA table with individual data was included in the revised manuscript (table 2).
     
  2. In the Method section, the authors described the independent samples test was used to test statistical differences between the means of TWO groups. Please clarify what the TWO groups were.
    ResponsePart of the Method section has been revised for better clarification. " The independent samples t test was used to test statistical differences between the means of two given groups, as in the comparison of flap thickness in men and women."
     
  3. In the Result section, the authors described thigh flaps were thicker when measured more proximal (p < 0.05). Please report the definite values of the items that were compared.
    ResponseThis statement was referring to PAP proximal (PAP1) and distal (PAP2). As this information is already included in Figure 3 and values represented in the graph, the sentence has been removed from the text for a better clarification.

Reviewer 3 Comments

  1. Authors should frame the current study within the context of existing research paradigms as well as emerging trends. Authors should provide a brief review of the literature addressing the 11 main issues in the Introduction section, such as: (1) limitations and/or flaws in previous studies, (2) unresolved gaps in the research, and (3) contradictory outcomes between studies.
    ResponseThe next paragraph was added in the Introduction to clarify existing research works and the need of our current study. “There are previous publications on ALT flap thickness measured with Doppler ultrasound [9,10], and only one using computed tomographic angiography (CTA) [11]. However, none of these studies compare ALT flap thickness to PAP flap thickness in the same patient.”
     
  2. Authors should specify whether the aim of the study is to promote treatment gains or prevent therapeutic harm. The research question is not clearly defined in the Introduction section.
    ResponseThe final paragraph of the introduction section has been modified to clarify the aim of our study: “The aim of this study was to compare the PAP flap thickness with the thickness of other thigh flaps that are more commonly used for intraoral reconstruction, and to identify factors influencing its thickness in our population using CTA. This information will be useful to facilitate flap selection based on desired tissue volume in populations with greater thigh thickness like our patients.”
     
  3. The conclusion regarding the description “The thigh flap that is least influenced by BMI is the PAP flap, and when it is harvested around a distal perforator it can be as thin as the ALT flap” is hard to understand. Please rephrase the sentences and clarify the main points.
    ResponseThe conclusion was rephrased. “All thigh flaps, including the PAP flap, tend to be thicker in women and those with high BMI. The thigh flap that is least correlated with BMI is the PAP flap. Also, the PAP flap thickness is not significantly different from that of the ALT/AMT flaps when measurement was made over the second perforator of the adductor magnus muscle, so harvesting the PAP flap around a distal perforator makes easier to obtain a flap as thin as the ALT flap would be in the same patient. Because of the similarity in thickness, the PAP flap can be considered in our population to be a good alternative of the ALT flap for intraoral reconstruction.”
     
  4. Suggestions for future research may be beneficial to overcoming current research limitations.
    ResponseThe following suggestions and ideas have been included at the end of the Discussion section. “In our study, our population included oncological patients. Nutritional status of these patients could be influencing our final results. Nevertheless, one of the most common reasons of microsurgical reconstruction of the head and neck in an adult patient is head and neck carcinoma. However, future research on correlating nutritional status with skin thickness will be useful in order to clarify differences between series with healthy and/or head and neck cancer patients.”

Reviewer 4 Comments

  1. Authors must specify the criteria used for the inclusion and exclusion of participants in the study group. 
    ResponseThey have been included in the first paragraph of the Material and Methods section. “The study sample comprised 72 legs of 36 patients. Inclusion criteria were patients who underwent head and neck microsurgical reconstruction with a fibula free flap, and who also underwent preoperative computed tomographic angiography (CTA). Exclusion criteria: the antecedent of previous thigh flap harvested”.
     
  2. Descriptive statistics (e.g., sex and age) should be illustrated using tables to summarize data in a constructive manner.
    ResponseThose data were added in Table 1.
     
  3. Authors should include a discussion on applying the current research to yield findings of clinical significance.
    ResponsePart of the Discussion was modified to address the abovementioned matter. “The main concern in our population could be its greater thickness compare to the ALT flap, but with our results we can show there is not much difference when the PAP flap is designed around a distal perforator. Our current results may encourage the decision of harvesting a PAP flap as an alternative of an ALT flap, when the indication is made for intraoral reconstruction.”
     
  4. Authors must acknowledge the possibility that bias has been introduced at any stage of the study, including selection bias (a non-representative study population) and information bias (imprecise measurements or incorrect recording of outcomes).
    ResponseThe following ideas have been included at the end of the Discussion section. “In our study, our population included oncological patients. Nutritional status of these patients could be influencing our final results. Nevertheless, one of the most common reasons of microsurgical reconstruction of the head and neck in an adult patient is head and neck carcinoma. However, future research on correlating nutritional status with skin thickness will be useful in order to clarify differences between series with healthy and/or head and neck cancer patients.”
     
  5. Also, authors should include a comprehensive description of the strengths and limitations of the research.
    ResponseThe strengths of this study have been outlined along the Discussion Section. I would like to summarize them as follows:
  • This the first study using Computed Tomographic Angiography to assess thickness of thigh flaps other than the anterolateral thigh flap.
  • To date, there have not been any anthropomorphic analysis of the thickness of PAP, as compared to the thickness of ALT or AMT free flaps, in the same patient.
  • This is the first report describing mean thickness of the PAP flap around both the first and second perforators of the adductor magnus muscle in a western population.
  • We also report that the PAP flap appears to be the least correlated with BMI in our population.

    The main limitation is the selection bias regarding to oncological patients included in this study. It has been explained in the last paragraph of the Discussion Section.

Editorial Comments

  1. Each reference number should be enclosed in square brackets, eg [1] or [1,2,3] or [1-3].
    ResponseIt has been done.
     
  2. Please define the abbreviations at first mention in the text, e.g., MDCT.
    ResponseIt has been done.
     
  3. The authors should define the significance of p value in the Method section.
    ResponseIt has been done.
     
  4. Please provide Figure 2 without any labeling, such as A, B, and C.
    ResponseWe have provided Figure 2 without labeling.
     
  5. In the Ethic Statement section, the authors stated the study was approved by the institutional ethics committee (Reference number 3965). Please clarify which hospital or institution is responsible for the institutional ethics committee.
    ResponseIt has been done.

Heredero S, Falguera MI, Sanjuan A, Dean A, Solivera J. Comprehensive analysis of profunda artery perforator flap thickness based on CTA. Int Microsurg J. 2019;3(3):2. https://doi.org/10.24983/scitemed.imj.2019.00120