Comparison between Different Perforator Imaging Modalities for the Anterolateral Thigh Perforator Flap Transfer: A Prospective Study

Single-staged revascularization and reconstruction after crush injury of the wrist and distal forearm: A protocolized approach

BACKGROUND

Amputation of the wrist or distal forearm after high-energy trauma due to a crushing mechanism is associated with complex tissue defects, making repair, and reconstruction challenging. Given the difficulty of this type of salvage, patients unfortunately experience a high revision amputation rate. However, a higher quality of life has been reported in patients with successful reconstructions. Herein, we described a protocolized approach for revascularization and reconstruction for functional hand salvage after traumatic amputation from a crushing mechanism using an anterolateral thigh flap (ALT).

METHODS

A retrospective review was performed between October 2016 and October 2023 for all patients who underwent single-stage emergent debridement, revascularization, and soft tissue coverage using the ALT after amputation at the level of the wrist or distal forearm secondary to high-energy crush injury. Charts were reviewed for the preoperative Mangled Extremity Salvage Score, intraoperative details including what structures were injured and the reconstructive method performed, and postoperative data such as follow-up duration, outcomes, and complications.

RESULTS

Eleven patients met the inclusion criteria with an average age of 35.5 (21-49) years old. The average size of the skin soft tissue defects was 17.3 × 8 cm (range, length: 13-25 cm, width: 6-13 cm), and all cases had associated injury to the underlying bone, nerves, and blood vessels. The average size of the ALT flap used for reconstruction was 19.2 × 9.8 cm (range, length: 14-27 cm, width: 7-15 cm). All patients had survival of the replanted limb. One patient experienced partial flap necrosis that required secondary debridement and skin graft. Nine patients healed without requiring any additional debridement procedures. Patient follow-up averaged 24.6 (12-38) months. All patients achieved satisfactory functional recovery with Grade II to III of Chen's criteria.

CONCLUSIONS

For patients with traumatic crush amputation to the wrist with surrounding soft tissue injury, thorough debridement, revascularization, and reconstruction of amputated limbs can be performed in a single stage using the ALT. A protocolized approach from two institutions is presented, demonstrating improved survival and reduced complications of the traumatized limb with improved long-term patient outcomes.

Introduction and preliminary application report for a novel 3D printed perforator navigator for fibular flap surgery

The aim of this study was to introduce and report on a 3D-printed perforator navigator and its clinical application. Integrated imaging and 3D printing techniques were employed for the design and manufacture of a perforator navigator. Key techniques included establishing a digital image coordinate system, localizing perforator fascia piercing points, creating a reference plane for the perforator course, and projecting the perforator course onto the body surface. All cases of maxillofacial defect repaired with free fibular myocutaneous flaps, from January 2019 to January 2022, were reinvestigated. Patients treated using traditional perforator localization methods were assigned into group Ⅰ, while those who had a navigator used during treatment were allocated to group Ⅱ. Outcome measurements included perforator positioning accuracy, perforator preparation time (PT), and flap growth score. Capillary refilling time and degree of flap swelling were recorded on the 1st, 3rd, and 7th days after surgery. On the 10th day after surgery, the flap survival situation was graded. In total, 25 patients were included in the study. Perforator preparation time for group Ⅱ was significantly less (p ＝ 0.04) than for group Ⅰ (1038.6 ± 195.4 s versus 1271.4 ± 295.1 s. In group Ⅱ, the mean positioning deviation for the perforator navigator was 2.12 cm less than that for the high-frequency color Doppler (p ＝ 0.001). Group Ⅱ also had a higher score than group Ⅰ for overall flap growth evaluation (nonparametric rank sum test, p ＝ 0.04). Within the scale of the study, it seems that perforator localization and navigation using a 3D-printed navigator is technically feasible, and helps to improve the clinical outcome of free fibular flaps. The perforator navigator will play a useful role in displaying the perforator course, improving the accuracy of perforator localization, reducing surgical injury, and ultimately enhancing flap success rate.

Utilization of two methods assisting perforator identification for brachial artery perforator propeller flap application

The brachial artery perforator propeller (BAPP) flap has the advantages of both local and perforator propeller flaps, and it remains relatively underused partly because of the anatomical variations of perforators in the medial arm. We aimed to review our preliminary experience using two different methods for perforator localization of a BAPP flap, including the application of a refined coordinate system (the ABC system) in the medial arm and indocyanine green angiography (ICGA). We evaluated the advantages and disadvantages of these methods and selected the optimal examination mode depending on detailed clinical settings. The perforator was identified for each patient using the ABC system and/or ICGA, depending on the clinical setting. Twenty-two patients underwent soft-tissue reconstructions with 22 BAPP flaps, and perforator localization for all the flaps was performed before surgery using the ABC system. Thirty-one perforators were localized before surgery and marked accordingly, all of which were visualized during surgery, except two, which were not found during the surgery. ICGA was used in six pre-expanded flaps at both stages of surgeries. Twenty-seven perforators were detected before surgery, and all of them were identified during surgery; the previously localized perforators found using the ABC system in the six patients were all reidentified using ICGA. Both the ABC system and ICGA were found to be useful for preoperative perforator localization in BAPP flap transfers. Each method has its unique downsides; however, they can supplement each other to facilitate safe and effective flap elevation. Therefore, selection of the optimal method based on the clinical settings is recommended.

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.

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.

Precision of Dynamic Infrared Thermography in Anterolateral Thigh Flap Planning: Identification of the Perforator Fascia Passage

Background The anterolateral thigh (ALT) flap is commonly utilized in reconstructive surgery. Preoperative perforator mapping facilitates dissection. Dynamic infrared thermography can be applied to identify ALT perforators. However, its accuracy has not been evaluated in detail before. Therefore, this study aimed to assess the precision of dynamic infrared thermography in ALT perforator localization.

Methods The survey site was defined as a 25 × 8 cm rectangle on the anterolateral thigh and a coordinate system was established. The area was examined consecutively by dynamic infrared thermography with a FLIR ONE camera after 2-minute fan precooling. Two surgeons then independently performed color duplex ultrasound on the basis of the identified hotpots.

Results Twenty-four healthy subjects were examined. About 74.8% of perforators were musculocutaneous or musculoseptocutaneous. The mean distance between study area center and perforator or hotspot center was 51.8 ± 27.3 and 46.5 ± 26.2 mm, respectively. The mean distance from hotspot center to sonographic perforator fascia passage was 15.9 ± 9.9 mm with a maximum of 48.4 mm. The positive predictive value of thermographic ALT perforator identification was 93%.

Conclusion Thermographic hotspot and perforator location diverge widely in ALT flaps. Dynamic infrared thermography can therefore not be used as standalone technique for preoperative ALT perforator identification. However, the application before color duplex ultrasound examination is a reasonable upgrade and can visualize angiosomes and facilitate the examination.

Thermography Supported Color Duplex Ultrasound Accelerates ALT Perforator Imaging

BACKGROUND

 The anterolateral thigh flap is a versatile and dependable perforator flap and is a popular choice in the reconstruction of various body sites. The variable perforator anatomy suggests preoperative perforator imaging to improve safety and speed of dissection. An innovative perforator imaging technique is thermography, which lately gained attention in plastic surgery.

METHODS

 Thirty-two healthy participants were included in this randomized study. One thigh was examined with dynamic infrared thermography and consecutively with ultrasound, while the contralateral thigh was examined with ultrasound as standalone technology.

RESULTS

 The application of dynamic infrared thermography prior to ultrasound perforator identification significantly accelerated the ultrasound examination duration by 90 to 130 seconds. The mean duplex ultrasound examination duration correlated positively with the hotspot and perforator quantity per thigh.

CONCLUSION

 The addition of thermographic perforator mapping can accelerate color duplex ultrasound anterolateral thigh perforator imaging. Furthermore, thermography supplements color duplex ultrasound with crucial information on angiosome location.

A Comparison of Handheld Doppler and Indocyanine Green Angiography for Perforator Localization

BACKGROUND

The preoperative identification of perforators is critical to the success of perforator flaps. Several technologies, including handheld Doppler (HHD) and indocyanine green angiography (ICGA), facilitate this process; however, each technology comes with unique downsides. This study directly compares the performance of HHD and ICGA in preoperative perforator identification and measures the effects of flap thickness and body mass index (BMI) on perforator localization.

METHOD

Data from preoperative HHD and ICGA assessments were compared with the criterion standard of intraoperative perforator localization. Sensitivity, specificity, accuracy, and positive predictive values were calculated for both and correlated with flap thickness and BMI.

RESULTS

Thirty flaps were transferred in 30 patients across 15 different donor sites. Indocyanine green angiography had higher sensitivity, accuracy, and positive predictive value (79.2%, 74.2%, and 87.5%, respectively) than HHD (55.6%, 46.6%, and 69.4%, respectively). Perforators detected by ICGA were used as flap pedicles in 21 cases compared with 13 with HHD. There were no correlations between HHD or ICGA performance and patient BMI (both P > 0.05). Increasing flap thickness was negatively correlated with the accuracy of ICGA ( P = 0.001) but not HHD ( P > 0.05).

CONCLUSIONS

Indocyanine green angiography was more sensitive, specific, and accurate than HHD in identifying perforators across various donor sites; however, its performance suffered in thicker flaps, whereas HHD did not. Patient BMI was not correlated with the performance of either technology. Additional research can further delineate the interrelationships of flap thickness and technologies for perforator localization.

Preoperative Peroneal Artery Perforator Mapping Using Indocyanine Green Angiography: A Prospective Clinical Trial

BACKGROUND

Perforator imaging is a prerequisite in preoperative planning of the peroneal perforator flap and the fibula skin island. Although reports indicate that indocyanine green angiography assessment method might be advantageous over conventional ultrasound-based techniques (i.e., Doppler and color duplex), in practice, clear evidence is lacking. Thus, a comparative assessment of the utility of indocyanine green angiography and ultrasound-based techniques in the identification of suitable lower leg skin perforators was performed.

METHODS

A prospective clinical cohort study with a series of 12 consecutive patients was conducted to assess indocyanine green angiography, Doppler ultrasound, and color duplex ultrasound techniques for preoperative perforator detection in the lower leg before free fibula flap harvest. Anatomical dissection served as a reference. Parameters measured were perforator spatial distance to the reference (precision), operative time expenditure, and ease of device usage for assessment/outcomes.

RESULTS

This study included 12 patients, with a total of 27 perforators. Exhibition of technique sensitivity and positive predictive values were as follows: indocyanine green angiography, 93 percent and 100 percent; Doppler ultrasound, 82 percent and 82 percent; and color duplex ultrasound, 89 percent and 86 percent, respectively. With regard to the indocyanine green angiography technique, the distance to the actual perforator location was significantly shorter, which aided detection and lesser time expenditure during operation.

CONCLUSIONS

The indocyanine green angiography technique proved to have high precision, sensitivity, positive predictive value, and easy-to-use capabilities because of its exceptional spatial and temporal information, compared to the conventional, ultrasound-based techniques. Therefore, indocyanine green angiography is superior for preoperative perforator imaging of the lateral lower leg.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Diagnostic, II.

Comparison of Detection of Superior Gluteal Artery Perforator by Indocyanine Green Fluorescence Near-Infrared ANGIOGRAPHY and Handheld Acoustic Doppler Sonography for Reconstruction of Sacral Pressure Injury

Aims: Pressure injury is a gradually increasing disease in the aging society. The reconstruction of a pressure ulcer requires a patient and surgical technique. The patients were exposed to the radiation risk under other ways of detection of perforators such as computed tomographic angiography and magnetic resonance angiography. Here, we compared two radiation-free methods of a superior gluteal artery perforator (SGAP), flap harvesting and anchoring. One is the traditional method of detecting only handheld acoustic Doppler sonography (ADS) (Group 1). The other involves the assistance of intraoperative indocyanine green fluorescent near-infrared angiography (ICGFA) and handheld ADS (Group 2). Materials and Methods: This is a single-center, retrospective, observational study that included patients with sacral pressure injury grades III and IV, who had undergone reconstructive surgery with an SGAP flap between January 2019 and January 2021. Two detection methods were used intraoperatively. The main outcome measures included the operative time, estimated blood loss, major perforator detection numbers, wound condition, and incidence of complications. Results: Sixteen patients underwent an SGAP flap reconstruction. All patients were diagnosed with grade III to IV sacral pressure injury after a series of examinations. Group 1 included 8 patients with a mean operative time of 91 min, and the mean estimated blood loss was 50 mL. The mean number of perforators was 4. Postoperative complications included one wound infection in one case and wound edge dehiscence in one case. No mortality was associated with this procedure. The mean total hospital stay was 16 days. Group 2 included 8 patients with a mean operative time of 107.5 min, and the mean estimated blood loss was 50 mL. The mean number of perforators was 5. Postoperative complications included one wound infection. No mortality was associated with this procedure. The mean total hospital stay was 13 days. Conclusions: The combination of detection of the SGAP by ICGFA and handheld ADS for the reconstruction of a sacral pressure injury provides a more accurate method and provides the advantage of being radiation-free.

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.

Comparison of Various Modalities Utilized for Preoperative Planning in Microsurgical Reconstructive Surgery

BACKGROUND

 The benefits of preoperative perforator imaging for microsurgical reconstruction have been well established in the literature.

METHODS

 An extensive literature review was performed to determine the most commonly used modalities, and their applicability, advantages and disadvantages.

RESULTS

 The review demonstrated varioius findings including decreases in operative time and cost with the use of CT angiography to identification of perforators for inclusion in flap design with hand-held Doppler ultrasound. Modalities like MR angiography offer alternatives for patients with contrast allergies or renal dysfunction while maintaining a high level of clarity and fidelity. Although the use of conventional angiography has decreased due to the availability of less invasive alternatives, it continues to serve a role in the preoperative evaluation of patients for lower extremity reconstruction. Duplex ultrasonography has been of great interest recently as an inexpensive, risk free, and extraordinarily accurate diagnostic tool. Emerging technologies such as indocyanine green fluorescence angiography and dynamic infrared thermography provide real-time information about tissue vascularity and perfusion without requiring radiation exposure.

CONCLUSION

 This article presents an in-depth review of the various imaging modalities available to reconstructive surgeons and includes hand held Doppler ultrasound, CT angiography, MR angiography, conventional angiography, duplex ultrasonography, Indocyanine Green Fluorescence Angiography and Dynamic Infrared Thermography.

Mapping 216 Perforator Flaps Using Highly Portable Tablet-Based Color Doppler Ultrasound (PT-CDU)

BACKGROUND

 The first reports of using color Doppler ultrasound for evaluation of the microvasculature were in the 1990s. Despite the early reports of its efficacy, color Doppler ultrasound did not achieve popularity nor general usage in part due to the cumbersome size, cost and poor resolution. This is the first study to demonstrate the potential utility of a new, highly portable, tablet-based color Doppler ultrasound (PT-CDU) system for imaging perforator flaps.

METHODS

 The deep inferior epigastric artery (DIEP), lateral arm (LA), anterolateral thigh (ALT), thoracodorsal artery (TDAP), and the medial sural artery (MSAP) perforator flaps were imaged within classic topographic landmarks to visualize and measure variables related to perforator flap anatomy. The Philips Lumify L12-4 linear array probe attached to the Samsung Galaxy Tab A tablet was the system used for all examinations.

RESULTS

 A total of 216 flaps were scanned in 50 healthy adult volunteers: 44 DIEP, 44 LA, 40 ALT, 48 TDAP, and 40 MSAP. Precise anatomic information regarding perforator size, number, and location was obtained. Overall, the percent of flaps having at least 1 perforator within the specified topographical landmarks was 89% for the DIEP, 84.1% for the LA, 72.5% for the ALT, 50% for the TDAP, and 30% for the MSAP (p = 2.272e-09). The percent of patients having an asymmetry (right versus left) in the number of perforators was 72.7% (ALT), 65% (DIEP), 59.1% (LA), 41.7% (TDAP), and 30% (MSAP) (p = 0.0351).

CONCLUSIONS

 Portable, tablet-based color Doppler ultrasound offers high-resolution images of perforators and represents a facile technology that may be of interest to microsurgeons in the planning of perforator flaps. Variations in vascular anatomy were well-demonstrated. This surgeon-driven imaging technology may represent an excellent alternative to other imaging modalities.