Perforator Variability of the Anterolateral Thigh Flap Identified on Computed Tomographic Angiography: Anatomic and Clinical Implications

Clinical application of digital technology in the use of anterolateral thigh lobulated perforator flaps to repair complex soft tissue defects of the limbs

Background

It is challenging to repair wide or irregular defects with traditional skin flaps, and anterolateral thigh (ALT) lobulated perforator flaps are an ideal choice for such defects. However, there are many variations in perforators, so good preoperative planning is very important. This study attempted to explore the feasibility and clinical effect of digital technology in the use of ALT lobulated perforator flaps for repairing complex soft tissue defects in limbs.

Methods

Computed tomography angiography (CTA) was performed on 28 patients with complex soft tissue defects of the limbs, and the CTA data were imported into Mimics 20.0 software in DICOM format. According to the perforation condition of the lateral circumflex femoral artery and the size of the limb defect, one thigh that had two or more perforators from the same source vessel was selected for 3D reconstruction of the ALT lobulated perforator flap model. Mimics 20.0 software was used to visualize the vascular anatomy, virtual design and harvest of the flap before surgery. The intraoperative design and excision of the ALT lobulated perforator flap were guided by the preoperative digital design, and the actual anatomical observations and measurements were recorded.

Results

Digital reconstruction was successfully performed in all patients before surgery; this reconstruction dynamically displayed the anatomical structure of the flap vasculature and accurately guided the design and harvest of the flap during surgery. The parameters of the harvested flaps were consistent with the preoperative parameters. Postoperative complications occurred in 7 patients, but all flaps survived uneventfully. All of the donor sites were closed directly. All patients were followed up for 13-27 months (mean, 19.75 months). The color and texture of each flap were satisfactory and each donor site exhibited a linear scar.

Conclusions

Digital technology can effectively and precisely assist in the design and harvest of ALT lobulated perforator flaps, provide an effective approach for individualized evaluation and flap design and reduce the risk and difficulty of surgery.

Pedicle Lengthening with Reducing Size Mismatch in Free Anterolateral Free Flap

When plastic surgeons reconstruct the defects for recurrent cancer, a longer vascular pedicle is often necessary because usable vessels are sacrificed in previous surgeries or radiotherapy. In this case, we would like to present another method for free anterolateral thigh flap pedicle elongation. A 59-year-old man was referred to our clinic for reconstruction after unilateral total maxillectomy and orbital exenteration due to recurrent squamous cell carcinoma. We need to cover the full-thickness defect in the left orbital area (8×7 cm sized), intraoral area (5×7 cm sized), and orbital floor. Due to prior surgeries and radiotherapy, we needed a vascular pedicle up to 15 cm for a distant recipient vessel. When harvesting the flap, we transected just proximal to the bifurcation site, harvested a muscular branch to vastus intermedius together, and used it for pedicle elongation by vessel turning over. A 17×6 cm sized musculocutaneous flap was harvested, and the total length of the pedicle was 15 cm. As the anastomosis was done at the distal portion of the vastus intermedius branch, there was no size mismatch with the superior thyroid artery. Both skin defects and the orbital floor were covered without any tension. The reconstruction was successful without any flap compromise 1 year after surgery. This case suggests another option for microsurgeons to lengthen the flap pedicle and reduce size mismatch using anatomical variability of the lateral circumflex femoral artery.

Improving the visualisation of perforator arteries for anterolateral thigh flaps harvest in CT angiography via sublingual glyceryl trinitrate

AIM

To investigate the improvement of image quality and visualisation of the anterolateral thigh (ALT) flap perforators on computed tomography angiography (CTA) after administration of sublingual glyceryl trinitrate (GTN).

MATERIALS AND METHODS

Sixty patients with oral lesions received thigh CTA examinations were divided randomly into two groups after administration of sublingual GTN (GTN group) or without administration of sublingual GTN (non-GTN group). Two radiologists calculated the signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and assessed the image quality of each vessel. Besides, the grade of thigh artery, the lumen diameter of deep femoral artery, lateral circumflex femoral artery (LCFA), the descending branch of LCFA and its proximal and distal perforators, and the number and type of visible perforators were evaluated quantitatively.

RESULTS

The SNR and CNR were not significantly different between the two groups (p>0.05). The image quality of CTA in the GTN group was significantly better than that in the non-GTN group (p<0.01). The lumen diameters of the deep femoral artery, LCFA, the descending branch of LCFA and its perforators were significantly larger in the GTN group than those in the non-GTN group (p<0.01). Compared with the non-GTN group, the number of visible perforators and the number of visible septocutaneous perforators were significantly more in the GTN group, and the qualitative grade of visible perforators was significantly higher (p<0.001).

CONCLUSIONS

The administration of sublingual GTN in preoperative thigh CTA can improve the image quality and visualisation of perforator vessels, thus could help surgeons to select the optimum ALT flaps.

Value of the combination of a smartphone-compatible infrared camera and a hand-held doppler ultrasound in preoperative localization of perforators in flaps

This study was conducted to evaluate the effectiveness of the FLIR ONE PRO, a thermal imaging camera for smartphones, combined with handheld Doppler (HHD) in the localization of perforator arteries and to assess the efficacy of the FLIR ONE PRO in distinguishing perforators of the descending branch of the lateral circumflex femoral artery (LCFA) from other perforators of the anterolateral thigh perforator (ALTP) flap. We enrolled 29 free perforator flaps from 22 patients in our study. Before surgery, dynamic infrared thermography was performed using a FLIR ONE PRO to visualize hotspots on the flaps. Subsequently, HHD was used to further determine the perforators under the hotspots, which were ultimately identified and confirmed through intraoperative findings. Additionally, infrared images of the ALTP flap were analyzed using FLIR Tools. The performances of the FLIR ONE PRO and FLIR ONE PRO + HHD groups were evaluated by comparing the intraoperative findings. Using FLIR ONE PRO + HHD, 119 hotspots and 106 perforators were identified during surgery. Using FLIR ONE PRO + HHD, sensitivity and positive predictive value were 97.87% and 88.46%, respectively, in the young (age≤45 years). In the elderly group (age>45 years), these percentages were 93.22% and 82.09%, respectively. In addition, we found that the FLIR ONE PRO could be useful for differentiating perforators in the descending branch of the LCFA from other perforators within 5 min. The results showed a sensitivity of 96.15%, a specificity of 98.9%, a positive predictive value of 96.15%, and a negative predictive value of 98.9%. Compared to using FLIR ONE PRO alone, the combined application of HHD and FLIR ONE PRO had a higher value in perforator localization by increasing the positive predictive value. The FLIR ONE PRO may have significance in the rapid prediction of perforators deriving from the descending branch of the LCFA.

Customizing Anterolateral Thigh Flap With Magnetic Resonance Angiography Differential Subsampling With Cartesian Ordering Imaging for Individualized Reconstruction of Extremity Defects

INTRODUCTION

Magnetic resonance angiography (MRA) with the differential subsampling with cartesian ordering (DISCO) imaging technique is rarely used in anterolateral thigh (ALT) flap. In our series, MRA DISCO imaging technique is used as a tool to customize ALT flaps. The aim of this study was to report the accuracy of cutaneous perforators identified by the MRA DISCO imaging.

METHODS

Nineteen patients underwent the MRA DISCO imaging for perforator mapping before the ALT flap transfer. A total of 38 ALT regions were studied on the MRA DISCO images. Flap thinning was performed under the guidance of MRA DISCO imaging.

RESULTS

The lateral circumflex femoral artery (LCFA) most commonly stems from the deep femoral artery (84.2%), followed by the common femoral artery (15.8%). The average number of perforator vessels per LCFA was 10.2 ± 1.7. The distinct oblique branch was observed in 16 out of the 38 ALT regions (42.1%). Among the 19 ALT flaps harvested, 5 were septocutaneous perforator flaps and 14 musculocutaneous perforator flaps. Ten were harvested based on the descending branch, and 3 used the oblique branch as the flap vascular pedicle. In addition, the displayed course and types of perforator vessels on the DISCO images of the 18 skin flaps were consistent with the intraoperative findings, with an accuracy of 94.7%.

CONCLUSIONS

The state of the cutaneous perforators of LCFA can be identified on the MRA DISCO images. The 3D-CE-MRA DISCO imaging is a practical method, which can ameliorate the design and customization of ALT flap for an individualized reconstruction.

A novel computed tomography angiography technique: guided preoperative localization and design of anterolateral thigh perforator flap

BACKGROUND

Anterolateral thigh perforator (ALTP) flap is considered a versatile flap for soft tissue reconstruction. Computed tomography angiography (CTA) is used for mapping perforator in abdominal-based reconstruction; however, it is less commonly used in ALTP due to its poor imaging efficacy. In this study, we introduced a novel CTA technique for preoperative localization and design of ALTP flap and evaluated its value in directing surgical reconstruction.

RESULTS

Thirty-five patients with soft tissue defects were consecutively enrolled. Modified CTA procedures, such as sharp convolution kernel, ADMIRE iterative reconstruction, 80 kV tube voltage, high flow contrast agent and cinematic rendering image reconstruction, were used to map ALTPs. A total of 287 perforators (including 884 sub-branches) were determined, with a mean of 5 perforators per thigh (range 2-11). The ALTPs were mainly concentrated in the "hot zone" (42%, 121/287) or the distal zone (41%, 118/287). Most perforators originated from the descending branch of the lateral circumflex femoral artery (76%, 219/287). Three perforator types, namely musculocutaneous (62%, 177/287), septocutaneous (33%, 96/287), and mixed pattern (5%, 14/287), were identified. The median pedicle length measured by two methods was 4.1 cm (range 0.7-20.3 cm) and 17.0 cm (range 4.7-33.9 cm), respectively, and the median diameter of the skin flap nourished by one perforator was 3.4 cm (IQR 2.1-5.7 cm). Twenty-eight ALTP flaps were obtained with the guidance of CTA, and 26 flaps survived after follow-up.

CONCLUSIONS

The proposed CTA mapping technique is a useful tool for preoperative localization and design of ALTP flap.

Clinical application of digital technology in the reconstruction of soft tissue defects of the lower extremity with free superficial circumflex iliac artery flap

Objective

This paper aims to investigate the feasibility and clinical effectiveness of digital technology in the clinical application of free superficial circumflex iliac artery flap (SCIP) for repairing soft-tissue defects in the lower extremities.

Methods

From January 2020 to December 2021, 16 patients with lower extremity soft tissue defects requiring flap repair were selected, and preoperative 3D digital reconstruction of the abdominal donor area and lower extremity recipient area were performed using digital technology combined with highly selective abdominal computed tomography angiography, and virtual design and flap cutting were performed using the software self-contained tool. During the actual surgery, the intraoperative design and excision of the superficial iliac circumflex artery were guided by the preoperative digital design, and the donor sites of the flap were closed directly.

Results

In all cases, digital models of the donor area of the abdominal SCIP were successfully established, which could clearly showed the distribution, course, and diameter of the main trunk and the perforators and other relevant anatomical information and successfully guided the design and excision of the flap during surgery. All flaps successfully survived after surgery, and both the flap recipient and donor sites healed in one stage. All patients were followed up for 2–12 months on average (mean 8.6 months), and the flaps were not bulky and had a satisfactory appearance, with no significant difference in color compared with the surrounding skin and a little pigmentation around the flap. Only linear scarring was left in the donor areas, and there was no restriction of hip movement.

Conclusion

This study used digital technology combined with a SCIP to repair lower extremity soft-tissue defects. The preoperative three-dimensional reconstruction of the digital model of the flap optimally designed the surgical plan, reduced the surgical risk and difficulty, shortened the surgical time, and had some significance for clinical precision, safety, and personalized design of the abdominal flap.

Computed tomography angiography-aided individualized anterolateral thigh flap design in the reconstruction of oral and maxillofacial soft tissue defects

PURPOSE

To evaluate a novel method and computed tomography angiography (CTA) for locating anterolateral thigh flap (ALTF) perforators to design individualized ALTFs to reconstruct maxillofacial soft tissue defects.

STUDY DESIGN

This study comprised a group of 36 patients (CTA group) with malignant oral and maxillofacial tumors who underwent CTA and who received individualized ALTFs and a group of 28 patients (control group) with the same condition but without preoperative CTA examination and with nonindividualized ALTFs. ALTFs in the CTA group were designed and harvested using the locating device and CTA, whereas ALTFs in the control group were designed and harvested according to each surgeon's experience.

RESULTS

Fifty perforators were located and 36 ALTFs harvested in the CTA group. In the control group, 34 perforators were located and 28 ALTFs harvested. Less time was required to locate the perforators in the CTA group. Moreover, the CTA group had a higher flap survival rate and better patient satisfaction regarding the postoperative aesthetics and phonetic and swallowing functions.

CONCLUSIONS

The results suggest that CTA and the locating device can be used to accurately locate ALTF perforators and that this method aids in the design and harvesting of individualized ALTFs to achieve good functional and aesthetic outcomes.

Preoperative perforator mapping of anterolateral thigh flaps using computed tomographic angiography and visual coordinate system for the reconstruction of head and neck defects

OBJECTIVES

The anterolateral thigh (ALT) flap is a versatile workhorse flap for the reconstruction of head and neck defects; however, variations in the location of perforators are a significant concern. This prospective study proposes a rapid, effective, and convenient method for mapping the location of sizeable perforators on the curved thigh skin surface using the visual coordinate system in computed tomographic angiography (CTA) images.

METHODS

Fourteen patients suffering from defects after head and neck carcinoma resection underwent CTA prior to ALT flap reconstruction at the Department of Otolaryngology-Head and Neck Surgery, Beijing Friendship Hospital, Capital Medical University, from January 2018 to August 2021. Using sterile gauze swab developing lines pasted on the patients' thighs, we established a coordinate system visualized both in CTA images and the thighs. The perforator information was then compared between the CTA and intraoperative findings.

RESULTS

Twenty-one perforators were detected on CTA in the designed flaps, which were also confirmed during the operation with a visual pulse. The course and source of the perforators were consistent with the intraoperative findings. The distances of perforator coordinate points between CTA and intraoperative findings were <5 mm. Another five perforators (mostly without visual pulse) found intraoperatively could not be identified on preoperative CTA. Most flaps survived in their entirety, and one flap suffered a small area of necrosis due to perforator compression.

CONCLUSION

This study demonstrated the efficacy of a novel perforator mapping method for anterolateral thigh flaps.

Microsurgical Anterolateral Thigh Flap for Reconstruction of Extremity Soft Tissue Defects in Pediatric Patients

BACKGROUND

The anterolateral thigh flap is one of the most widely used flaps because it has the advantages of less damage to the donor site, no sacrifice of main blood vessels, and abundant soft tissue. However, the application of anterolateral thigh flap in children is relatively rare because of small blood vessels and rapid physiological changes. The aim of this study was to explore the effectiveness and characteristics of free anterolateral thigh flaps for the reconstruction of extremity soft tissue defects in pediatric patients.

PATIENTS AND METHODS

This study included 26 pediatric patients, with an average age of 6.7 years (range, 2-13 years). There were 5 cases of upper limb defects and 21 cases of lower limb defects, all of which were accompanied by exposed bones or tendons. The causes of defects included traffic injury in 9 cases, mechanical injury in 7 cases, collision injury in 4 cases, spoke injury in 3 cases, cicatricial contracture in 2 cases, and fibroma in 1 case. All defects were reconstructed with free anterolateral thigh flaps.

RESULTS

Twenty-six anterolateral thigh flaps were harvested, including 15 fasciocutaneous flaps and 11 musculocutaneous flaps. The mean size of the flap was 73.4 cm2 (range, 4 × 3 to 24 × 8 cm). The donor sites were sutured directly in 19 cases and underwent split-thickness skin grafting in 7 cases. There were 3 cases of vascular crisis, 3 cases of flap edge necrosis, 3 cases of infection, 1 case of pressure ulcer, and 1 case of dehiscence after surgery. Eleven patients had scar hyperplasia in the donor site. A total of 34 reoperations were performed, including 14 flap debulking, 7 debridement, 4 skin graft, 3 vascular crisis re-exploration, and 6 other procedures.

CONCLUSIONS

Free anterolateral thigh flap was a safe and reliable option for reconstructing soft tissue defects of extremities in pediatric patients. Notably, the incidence of scar hyperplasia in the donor site and the possibility of reoperation in pediatric patients were higher than those in adult patients.

Modified Reconstruction of Brown II Defects With Anterolateral Thigh Flaps Following Tumor Resection

OBJECTIVE

Maxillary defects reconstructed with flaps usually cause nasalomaxillary fistula, discomfort oral lining, and poor function of denture. To resolve these problems, this study introduces a modified method of anterolateral thigh flap (ALTF) with skin and myofascial paddles to reconstruct nasal and oral lining of maxillary defects.

METHODS

This study retrospectively reviewed 66 consecutive patients of Brown II maxillary defects following tumor resection reconstructed with ALTFs of modified or conventional methods. In modified group, oral lining was reconstructed with myofascial paddle and nasal lining was reconstructed with skin paddle. The functional and aesthetic outcomes, and the scores based on the University of Washington quality of life questionnaire were assessed.

RESULTS

All flaps were successful in reconstruction of Brown II maxillary defects. No nasalomaxillary fistula and obstruction of the nasal cavity were found in modified ALTFs group. The functions of removable denture were better in modified ALTFs group. There was no significant difference about tumor recurrence, range of mouth opening, and aesthetic outcomes between the 2 groups.

CONCLUSIONS

The modified method of ALTF with skin and myofascial piddle to reconstruct Brown IIa and IIb defects following tumor resection is simple and reliable, which improves the oral comfortability and function of denture, and avoids obstruction of the nasal cavity.

Color Doppler Ultrasound versus Computed Tomography Angiography for Preoperative Anterolateral Thigh Flap Perforator Imaging: A Systematic Review and Meta-Analysis

BACKGROUND

 The anterolateral thigh (ALT) perforator flap is a commonly used flap with a predictable, though often variable, perforator anatomy. Preoperative imaging with color Doppler ultrasound (CDU) and computed tomography angiography (CTA) of ALT flap perforators can be a useful tool for flap planning. This study provides a complete review and analysis of the relevant preoperative ALT imaging literature.

METHODS

 Studies related to preoperative CDU and CTA imaging were reviewed, and information related to imaging method, sensitivity, false-positive rates, and perforator course identification (musculocutaneous vs. septocutaneous) were analyzed.

RESULTS

 A total of 23 studies related to preoperative ALT flap CDU and CTA imaging were included for review and analysis. Intraoperative perforator identification was compared with those found preoperatively using CDU (n = 672) and CTA (n = 531). Perforator identification sensitivity for CDU was 95.3% (95% CI: 90.9-97.6%) compared with the CTA sensitivity of 90.4% (95% confidence interval [CI]: 74.4-96.9%). The false-positive rate for CDU was 2.8% (95% CI: 1.1-4.5%) compared with 2.4% (95% CI: 0.7-4.1%) for CTA. Accuracy of perforator course identification was 95.5% (95% CI: 93.6-99.2%) for CDU and 96.9% (95% CI: 92.7-100.1%) for CTA.

CONCLUSION

 CDU provides the reconstructive surgeon with greater preoperative perforator imaging sensitivity compared with CTA; however, false-positive rates are marginally higher with preoperative CDU. Preoperative imaging for ALT flap design is an effective tool, and the reconstructive surgeon should consider the data presented here when selecting a flap imaging modality.

Preoperative Computed Tomography Angiography for ALT Flaps Optimizes Design and Reduces Operative Time

BACKGROUND

 Computed tomography angiography (CTA) has been widely used for perforator mapping in abdominal-based reconstruction, but it is less widespread in the anterolateral thigh (ALT) flap. However, CTA may be quite useful for ALT planning, as this flap has demonstrated substantial variability in intrapatient bilateral vascular anatomy. This study investigated whether standard use of preoperative CTA resulted in selection of the donor extremity with preferential perforator anatomy, and whether this affected operative time and postoperative outcomes.

METHODS

 A retrospective review of 105 patients who underwent proposed ALT flap reconstruction was performed. Seventy-nine patients received bilateral lower extremity CTAs, which were evaluated for dominant perforator anatomy (septocutaneous, musculoseptocutaneous, or musculocutaneous). Donor extremity selection was noted, and predicted perforator anatomy was compared with that encountered intraoperatively.

RESULTS

 Among the 73 patients who received bilateral imaging and ultimately received an ALT, congruent findings between imaging and surgical exploration were observed in 51 (69.8%) patients. Thirty (37.9%) patients had asymmetric perforator anatomy between their bilateral extremities on imaging. Among these, the leg with optimal perforator anatomy was selected in 70% of cases. There were no significant reductions among postoperative complication rates, but selection of the donor site with preferential anatomy was associated with a decrease in operative time (p = 0.049) among patients undergoing extremity reconstruction.

CONCLUSION

 CTA is a useful tool for optimizing donor site selection for ALT flaps and reducing operative time. We believe that standard use of preoperative CTA in ALTs warrants further consideration.