Preoperative Vascular Planning of Free Flaps: Comparative Study of Computed Tomographic Angiography, Color Doppler Ultrasonography, and Hand-Held Doppler

[Using a smartphone-compatible thermal camera (FLIR One) for preoperative mapping of DIEP perforators]

INTRODUCTION

The success of surgeries involving free flaps largely depends on accurate preoperative mapping of perforator arteries. Various imaging techniques, such as Doppler ultrasound and CT angiography, are typically used, each having its advantages and disadvantages in terms of cost, accuracy, and patient risk. The main objective of our study is to compare the effectiveness of the FLIR One device for detecting these arteries compared with traditional methods. Thermal imaging appears to be a simpler, less expensive, and less invasive alternative for surgical planning.

MATERIAL AND METHOD

The study, conducted at the Regional Hospital Center of Nancy, included 25 free flaps (DIEP) on an exclusively female cohort of 22 patients, with follow-up from 2022 to 2023. Before the procedure, an abdominal-pelvic CT angiography was performed, followed by additional evaluation with thermal imaging using FLIR One and acoustic Doppler examination on the eve of the operation. This approach aimed to provide precise mapping of vascular perforators for each patient. Three different operators performed these markings, and the results were then compared with intraoperative observations. The imaging protocol also included a Doppler examination to validate the results of the thermal imaging. Statistical analyses with intraclass correlation coefficients (ICC) were performed to evaluate the correlation between different preoperative localization methods of perforating vessels.

RESULTS

In 22 patients undergoing 25 DIEP flaps for breast reconstructions, three imaging techniques were used to identify vascular perforators: thermal imaging with FLIR, acoustic Doppler, and CT angiography. FLIR identified the most perforators (n=137), followed by acoustic Doppler (n=128) and CT angiography (n=126). Comparing these with intraoperative results, 66% of perforators identified by FLIR were confirmed, 70% for acoustic Doppler, and 95% for CT angiography. The ICCs shows a significant correlation between these imaging techniques and intraoperative results. FLIR demonstrated a strong correlation with intraoperative observations (ICC of 0.74, P<0.001), followed by a moderate correlation with acoustic Doppler (ICC of 0.56, P<0.03) and CT angiography (ICC of 0.52, P<0.006).

CONCLUSION

The study concludes that thermal imaging with FLIR is a reliable and effective tool for locating vascular perforators. Although the study and FLIR have their own limitations, the tool presents several advantages such as ease of use, speed, and affordability. These characteristics make FLIR particularly attractive as a complement to traditional detection methods, such as acoustic Doppler and CT angiography.

Free-flap reconstruction methods in head-and-neck oncologic surgery: A CROSS practice survey of members of the French GETTEC Head-and-Neck Tumor Study Group

OBJECTIVE

To survey practices concerning the use of anticoagulants and antiplatelets in microvascular free-flap reconstruction following oncological surgery of the head and neck.

METHODS

A survey of practices was carried out between September 2022 and March 2023. An online questionnaire was sent to members of the French GETTEC Head-and-Neck Tumor Study Group in all French centers practicing head-and-neck cancer surgery with reconstruction using microvascular free-flaps. The questionnaire asked surgeons about their practices regarding the use of intra- and postoperative anticoagulants and antiplatelets, preoperative management of comorbidities, and prevention of postoperative complications.

RESULTS

Sixty-one percent of the 38 respondents (23/38) used intraoperative intravenous heparin injection, associated to flap irrigation with heparin for 76% of surgeons (29/38) and/or a heparin solution bath for 37% (14/38). Postoperative anticoagulation was used by 95% of surgeons (36/38), and antiplatelets by 40% (15/38). Postoperatively, 40% (15/38) carried out monitoring using an implantable micro-Doppler probe, associated to analysis of clinical characteristics of the flap.

CONCLUSION

Reconstructive surgery using microvascular free-flaps involves numerous factors that can influence success. Prospective studies, particularly concerning the management of anticoagulants, could enable a national consensus on methods for free-flap reconstruction.

Identifying diversity of patient anatomy through automated image analysis of clinical ultrasounds

PURPOSE

Central venous catheterization (CVC) carries inherent risks which can be mitigated through the use of appropriate ultrasound-guidance during needle insertion. This study aims to comprehensively understand patient anatomy as it is visualized during CVC by employing a semi-automated image analysis method to track the internal jugular vein and carotid artery throughout recorded ultrasound videos.

METHODS

The ultrasound visualization of 50 CVC procedures were recorded at Penn State Health Milton S. Hershey Medical Center. The developed algorithm was used to detect the vessel edges, calculating metrics such as area, position, and eccentricity.

RESULTS

Results show typical anatomical variations of the vein and artery, with the artery being more circular and posterior to the vein in most cases. Notably, two cases revealed atypical artery positions, emphasizing the algorithm's precision in detecting anomalies. Additionally, dynamic vessel properties were analyzed, with the vein compressing on average to 13.4% of its original size and the artery expanding by 13.2%.

CONCLUSION

This study provides valuable insights which can be used to increase the accuracy of training simulations, thus enhancing medical education and procedural expertise. Furthermore, the novel approach of employing automated data analysis techniques to clinical recordings showcases the potential for continual assessment of patient anatomy, which could be useful in future advancements.

Increased safety in periodontal surgery: Doppler ultrasound for detection of relevant palatal blood vessels-A proof-of-concept and cross-sectional study

AIM

To evaluate the suitability of a Doppler ultrasound probe in detecting the greater palatine artery or its greater branches non-invasively.

MATERIALS AND METHODS

The palatal mucosa of 108 participants (median age 34 years, 51 female) was systematically divided into transversal sectors, each aligning with the positions of the upper molars (M), premolars (P) and canine teeth (C), aiming to facilitate precise and consistent localization of the detected palatal blood vessel across different patients. Blood flow of the palatal blood vessels, presumably, was located by scanning the palatal vault bilaterally using an 8-MHz ultrasound probe linked to a transducer. The distance to the corresponding tooth was measured using a millimetre-scale periodontal probe.

RESULTS

Within the regions of M2 to P1, the ultrasound transducer gave a delimitable acoustic pulse signal in 80%-98% of all measurements. The measured median distances between the determined position of the artery and the corresponding teeth ranged from 13 to 15 mm, with smaller distances in the anterior region. In several sectors, the distance was significantly higher for men (C: p = .048; P1: p = .041, M1: p < .01; M2: p = .034).

CONCLUSIONS

Use of the Doppler ultrasound transducer might be a promising approach to non-invasively detect relevant palatine blood vessels preoperatively. It, therefore, might have the potential to reduce the risk of accidental injury during palatal surgery.

High-frequency ultrasound-assisted perforator mapping enhances efficiency in microsurgical reconstruction using thin ALT and SCIP flaps

BACKGROUND

With the growing demand for the use of thin perforator flaps, obtaining knowledge on the superficial anatomy of perforators is imperative for stable flap elevation. Conventional modalities for perforator mapping fall short in providing such information. High-frequency ultrasound (HFUS), known for visualizing the superficially located anatomic structures, may potentially fill this void. This study aimed to evaluate the effectiveness of HFUS in the outcome of anterolateral thigh (ALT) and superficial circumflex iliac artery perforator (SCIP) flap-based reconstructions.

METHODS

Consecutive patients who underwent free ALT or SCIP flap-based reconstruction from January 2021 to November 2022 were retrospectively reviewed. Perforator mapping was conducted using a handheld Doppler during the first year, while HFUS was used in the latter part. The two techniques were compared in terms of flap harvesting time and perfusion-related complication rates while considering the flap elevation plane.

RESULTS

In total, 123 cases were analyzed, including 82 ALT flaps (41 in each group) and 41 SCIP flaps (16 in the Doppler and 25 in the HFUS group). The time required for flap elevation exhibited a tendency to decrease in the HFUS group, with a significant difference observed in cases involving thin flap elevation (super-thin ALT flaps and pure-skin-perforator SCIP flaps). Compared with the Doppler group, the HFUS group demonstrated significantly lower rates of PRCs, particularly partial flap necrosis. This difference remained significant in multivariable analyses.

CONCLUSION

Our results suggest that HFUS might be an appealing modality for perforator mapping in cases requiring thin ALT and SCIP flap.

Pain relief effect of angiopuncture therapy on patients with postoperative pain: A clinical trial

BACKGROUND

The objective of this study is to study the pain relief effects of angiopuncture therapy in patients with postoperative pain.

METHODS

Forty-one patients were randomly selected based on the inclusion and exclusion criteria. Doppler imaging was performed to locate the cutaneous perforator. Angiopuncture was performed on the first postoperative day. A Numerical Rating Scale was used to evaluate the degree of pain before and after angiopuncture. Utilizing the paired t test or Wilcoxon signed rank test, all pre- and post-data were examined, and further subgroup analysis based on time was performed.

RESULTS

Variance analysis revealed a significant difference before and after angiopuncture (P < .05). The results of the subgroup analysis showed the pain-relieving effect of angiopuncture for postoperative pain patients at the time points of 6 hours, 12 hours, 24 hours, 48 hours, and 72 hours was apparent (P < .05).

CONCLUSION

The angiopuncture therapy approach may assist in pain relief in patients with postoperative pain.

PreFlap: From Photoacoustic Tomography Images to Vascular Mapping Sheets for Improved Preoperative Flap Evaluation

OBJECTIVE

Advancements in technology have improved image acquisition and processing in the field of medical imaging, giving medical doctors the tools to implement effective medical care. In plastic surgery, despite advances in anatomical knowledge and technology, problems in preoperative planning for flap surgery remain.

METHODS

In this study, we propose a new protocol to analyze three-dimensional (3D) Photoacoustic tomography images and generate two-dimensional (2D) mapping sheets that can help surgeons identify perforators and the perfusion territory during preoperative planning. The core of this protocol is PreFlap, a new algorithm that converts 3D photoacoustic tomography images into 2D vascular mapping images.

CONCLUSION

Experimental results demonstrate that PreFlap can improve preoperative flap evaluation, thus can greatly saving surgeons' time and improving surgical outcomes.

Handheld Doppler Detection and Light Illumination for Vascular Mapping in Nasal Reconstruction

BACKGROUND

The application of the expanded forehead flap in nasal reconstruction has the advantage of being able to provide a sufficient amount of flap and can provide good aesthetic results. For an expanded forehead flap to survive, there must be adequate arterial supply and venous return. Despite this, limited studies have been conducted on preoperative vascular mapping and the design of the expanded forehead flap for nasal reconstruction. In this article, the authors present a technique of hand-held Doppler detection with light illumination for vascular mapping.

PATIENTS AND METHODS

The study included patients who underwent total nasal reconstruction with expanded forehead flaps between May 2016 and April 2021. The design of the flap was based on the result of preoperative vascular detection by hand-held Doppler detection assisted by light illumination.

RESULTS

A total of 32 patients underwent total nasal reconstruction with an expanded forehead flap. The distal part of the flap became necrotic 1 week after the surgery in 2 patients. Following dressing changes and the administration of antibiotics, the distal flap in these patients survived well. No complications were reported in the long term.

CONCLUSIONS

Hand-held Doppler detection combined with light illumination is a convenient and effective preoperative design method for nasal reconstruction with an expanded forehead flap. All flaps survived well in the long term.

LEVEL OF EVIDENCE

Level IV.

Utility of preoperative colour flow Doppler assessment of perforator anatomy in medial sural artery perforator (MSAP) free flaps

PURPOSE

It is known that the vascular perforators upon which the medial sural artery perforator (MSAP) flap is based are subject to considerable variation. This study seeks to evaluate the use of colour flow Doppler (CFD) as an imaging technique to establish the presence of suitable vessels, the discriminatory findings from that imaging, the rate of flap abandonment and flap complications.

METHODS

All patients undergoing MSAP in our institution since 2015 had a pre-operative CFD using a standardised technique. A prior group of 22 patients not having CFD acted as a control group. Data were  collected prospectively.

RESULTS

Fourteen patients had CFD. In one patient, no suitable vessels were found. In 13 patients, vessels of suitable size and position were identified, which then correlated precisely with operative findings. Three had suitable vessels in one leg only. No flaps in the CFD group were abandoned. One flap in the CFD group was partially lost. One flap in the prior control group was abandoned.

CONCLUSIONS

CFD provided reliable discriminatory information to decide on flap suitability/which leg and correlated precisely with operative findings, with no flap abandonment. Flap survival rate was very high.

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.

Comparison of Hand-Held Doppler and Indocyanine Green Angiography in Preoperative Design of Expanded Forehead Flaps for Nasal Reconstruction

BACKGROUND

Despite the different approaches for detection of perforators, methods of vascular mapping of the expanded forehead flap for nasal reconstruction are rarely described. This article aimed to present our experience in the preoperative design of the expanded forehead flap for nasal reconstruction and to compare the clinical practice of hand-held Doppler and indocyanine green angiography (ICGA) in vascular mapping for nasal reconstruction with the expanded forehead flap.

METHODS

From October 2019 to April 2022, 26 patients underwent nasal reconstruction using expanded forehead flap. The authors performed preoperative vascular mapping on 16 patients by hand-held Doppler alone, and on 10 patients by hand-held Doppler and ICGA primary outcomes considered were the visualization of the main vascular course of the flap obtained by hand-held Doppler or ICGA, intraoperative observation of the flap, and its postoperative complications.

RESULTS

Indocyanine green angiography provides a better detection in distal flap and the branches of the supratrochlear artery. Vein detection by ICGA generally corresponds to the results obtained by the combination of hand-held Doppler and transillumination test. In the group that only used hand-held Doppler, 2 patients presented hemodynamic complications in the margin of the flap and 1 patient presented partial necrosis postoperatively. No complication was found in the group that used ICGA.

CONCLUSIONS

It is recommended to use the ICGA for preoperative planning, as it yields highly accurate vascular courses. As an alternative to other methods, hand-held Doppler is also an effective tool.

LEVEL OF EVIDENCE

IV.

The use of the chimeric conjoint flap technique for complex defects reconstruction throughout the body: Clinical experience with 28 cases

BACKGROUND

Large soft tissue defects reconstruction represents a frequent and complex challenge in plastic surgery. A critical point regards the equilibrium between the need of large amount of tissue, while minimizing donor site morbidity. This is a common issue that plastic surgeons face in their clinical practice. In this context, the chimeric conjoint flap technique can be a valuable option, allowing to better exploit many well-known procedures. The purpose of the present work is to show the reconstructive efficacy and reliability of this technique resorting to many different well-known flaps. No such a comprehensive collection of cases is available so far dealing with this procedure.

PATIENTS AND METHODS

Twenty-eight patients presenting large defects throughout the body were treated by means of different flaps, designed according to the chimeric conjoint flap concept. Patients' mean age was 61.9 years old (range 18-82 years), 20 were males and 8 females. The size of the defects ranged from 7 cm × 6 cm to 25 cm × 18 and presented shapes or localizations that were complex to be covered with a regular flap. The defects were located in 11 cases in the lower limbs, in 9 cases in the head and neck region, in 5 cases in the groin, and in 2 cases in the thorax. Cause of the defect was tumor resection in 20 cases, trauma-induced necrosis in 5 cases, Fournier's gangrene in 2 cases, and a chronic ulcer in 1 case. Fourteen flaps were free flaps while 14 were pedicled flaps. The chimeric conjoint flap technique consists in splitting the skin paddle a flap into two smaller island that can be rearranged in order to match the particular requirements of the recipient site. Different flaps were employed: the anterolateral thigh (ALT) flap was used in 19 cases, latissimus dorsi (LD) musculocutaneous flap in 4 cases, deep inferior epigastric (DIEP) in 3 cases, medial sural artery perforator (MSAP) in 1 case, free radial forearm flap (RFFF) in 1 case.

RESULTS

All the 28 patients were successfully treated. In 6 cases minor complications were encountered, 5 at recipient site and 1 at donor site, who were all managed conservatively. No second procedures were required. The mean follow-up period was 8.4 months (range 3-12 months). At the last follow-up evaluation all the patients reached an acceptable cosmetic result and, when limbs were affected, complete range of motion restoration.

CONCLUSIONS

The present case series provide promising evidence regarding the reliability and versatility of the chimeric conjoint flap technique for large and delicate defect reconstructions throughout the body.

Maximizing the Versatility of Thin Flap from the Groin Area as a Workhorse Flap: The Selective Use of Superficial Circumflex Iliac Artery Perforator (SCIP) Free Flap and Superficial Inferior Epigastric Artery (SIEA) Free Flap with Precise Preoperative Planning

BACKGROUND

 This study aimed to evaluate the usefulness of the selective use of the superficial circumflex iliac artery perforator (SCIP) and the superficial inferior epigastric artery (SIEA) flap as a workhorse flap from the groin area with precise preoperative surgical planning.

METHODS

 A total of 79 free flap reconstructions were performed in the study period; 35 SCIP free flaps and 19 SIEA free flaps were performed in the study period. Detailed preoperative surgical planning was performed using computed tomography (CT) angiography and color Doppler ultrasound. Detailed anatomical information of the flaps and reconstructive outcomes were evaluated.

RESULTS

 Flap characteristics between SCIP free flaps and SIEA free flaps were similar. The average transverse distance of the perforator from anterior superior iliac spine was 15.91 cm in SCIP free flaps and 43.15 cm in SIEA free flaps. The overall flap success rate was 96.4%. Majority of the patients achieved satisfactory contour without debulking surgery. Donor site morbidity was minimal with one case of wound dehiscence.

CONCLUSION

 The selective use of the SCIP and SIEA free flap in groin area is a safe and useful technique. The surgical outcomes were reliable and similar between the SCIP and SIEA free flaps. Preoperative vascular planning using CT angiography and color Doppler ultrasound is essential for selecting the proper flap.

A three-dimensional visualization of the full-field surgical region based on thin-slice MRI: A helpful approach for simultaneously guiding tumor resection and perforator flap elevation

Background

The goal of the current study was to explore the application of preoperative three-dimensional reconstruction (3DR) based on thin-slice magnetic resonance imaging (MRI) in the simultaneous guidance of en bloc tumor resection and adjacent perforator flap elevation.

Methods

The prospective cohort included 35 patients diagnosed with either soft tissue sarcoma or squamous cell skin cancer between 2019 and 2021. The preoperative 3DR based on thin-slice MRI illustrated the spatial anatomical relationship among the tumor, underlying muscle, adjacent perforator vessels, and bone around the surgical region. The accuracy of preoperative imaging data was verified by intraoperative vessel dissection and postoperative pathological measurements.

Results

Tumor size from 3DR data showed relatively high concordance rates with pathological measurements within the 95% limits of agreement. An average of three perforators (range: 1–7) with a mean diameter of 0.32 cm (range: 0.18–0.74 cm) from the 3DR were present in our study. The average distance between tumor boundary and perforator piercing sites on the 3DR was 2.2 cm (range: 1.2–7.7 cm). The average length of artery perforator coursing along the subcutaneous tissue was 5.8 cm (range: 3.3–25.1 cm). The mean flap harvest time was 55 mins (range: 36–97 min). The average flap size was 92.2 cm² (range: 32–126 cm²). One perforator flap occurred distal partial necrosis.

Conclusion

A thorough understanding of anatomical structures in the surgical region according to full-field 3DR based on thin-slice MRI can improve the performance of radical resection of the tumor and adjacent perforator flap transfer, especially for junior surgeons with a poor experience.

"Reverse tensor fascia latae perforator flap for reconstruction of knee defect: Anatomic study by computed tomographic angiography and a case report"

BACKGROUND

Reverse anterolateral thigh perforator (ALTp) pedicle flap can be used to reconstruct perigenicular defect thanks to the anastomoses between the descending branch of the lateral circumflex femoral artery (LCFA) and the perigenicular network. In a few cases, however, patients do not present any ALTp. We hypothesized that, in such cases, an adjacent perforator, the tensor fascia latae perforator (TFLp), emerging from the LCFA ascending branch, could be used instead. To assess the feasibility of this technique, a radiological study was conducted. A first patient was treated using this option.

METHODS

Sixty lower limb computed tomography were analyzed. The first treated patient was a 50-years-old man suffering from a 5-mm chronic bone exposure and osteomyelitis. Other reconstructive options were not indicated since he presented a multiscarry leg, severe arteriopathy, and no ALTp. A TFLp flap was raised, and the LCFA ascending and descending branches were dissected in continuity. After ligation of the LCFA, the blood flow reversed in the descending branch to irrigate the flap through the ascending branch.

RESULTS

A TFL perforator was observed in all the cases of the radiological study. The LCFA branching pattern was compatible with achieving a reverse TFL perforator flap in 43 cases (72%). The average pedicle length was 32 cm (22-38 cm). In the first clinical case, the flap covered the defect easily. After three months, the patient showed no evidence of infection recurrence and recovered a painless walk.

CONCLUSION

The reverse TFLp flap can be a suitable option for perigenicular reconstruction.

[Clinical application of computed tomographic angiography in predicting the vascular pedicle length of the proximally-based anterolateral thigh flap]

OBJECTIVE

To explore the reliability and effectiveness of prediction of the pedicle length of the proximally-based anterolateral thigh (pALT) flap which was used to repair the defects following the resection of various malignant tumors using computed tomographic angiography (CTA).

METHODS

The clinical data of 12 patients who met the selection criteria by using pALT flap to repair wounds left after malignant tumor resection between June 2015 and December 2020 were retrospectively analyzed. There were 5 males and 7 females; the age ranged from 16 to 80 years, with an average age of 54.4 years. After tumor resection, the soft tissue defect ranged from 15 cm×5 cm to 30 cm×12 cm; defect sites included 4 cases of lower abdomen, 3 cases of groin, 2 cases of thigh, and 3 cases of buttocks. Preoperative CTA was used to obtain the location information of the descending branch of the lateral femoral circumflex artery and its perforators by maximum density projection, and the length of the pedicle of pALT flap was estimated. Fasciocutaneous flap (5 cases) or myocutaneous flap (7 cases) were cut during operation to repair the defect, and the size of flap ranged from 20 cm×7 cm to 30 cm×12 cm. The donor site of thigh was directly sutured (11 cases) or repaired with skin graft (1 case). Bland-Altman analysis was used to detect the consistency between the pALT flap vascular pedicle length estimated by CTA and the pALT flap vascular pedicle length actually obtained during operation.

RESULTS

One case had distal blood supply disturbance of the flap and was repaired with skin graft after debridement; the remaining 11 flaps survived. All donor and recipient incisions healed by first intention. All 12 cases were followed up 1-12 months, with an average of 4.3 months. One patient died of pelvic tumor recurrence at 6 months after operation, and no tumor recurrence was found in the other patients. Preoperative CTA estimated that the length of pALT flap vascular pedicle was 9.3-24.7 cm, with an average of 14.7 cm; the actual length of pALT flap vascular pedicle was 9.5-25.0 cm, with an average of 14.8 cm. Bland-Altman analysis showed that there was no significant difference between the pALT flap vascular pedicle length estimated by CTA before operation and the pALT flap vascular pedicle length actually obtained during operation, and the average difference was 0.1 (95% consistency limit: -0.89, 0.74), indicating that they had good consistency.

CONCLUSION

CTA can be accurately used to localize the perforator and predict the possible pedicle length of the pALT flap. When performing a pALT flap surgery, preoperative CTA is helpful for surgeons to make a preliminary assessment of the difficult of the operation. The time for exploration of perforators and dissection of the vascular pedicle, and complications can be reduced, and the safety of the operation can be improved.

An Innovative and Economical Device for Ischemic Preconditioning of the Forehead Flap Prior to Pedicle Division: A Comparative Study

BACKGROUND

 Ischemic preconditioning of the forehead flap prior to pedicle division helps to improve angiogenesis. Clamping the pedicle by a clamped rubber band with vessel forceps is often clinically applied. However, the severe pain and unstable blocking effect influenced the preconditioning process. In this study, we described an innovative device designed for ischemic preconditioning and compared its efficacy with the clamped rubber band.

METHODS

 The device consists of a self-locking nylon cable tie with a buckle and a rubber tube. The rubber tube is fed over the cable tie to act as a soft outer lining and the cable tie is tightened across the pedicle to block the perfusion for ischemic preconditioning. This device and the standard clamped rubber band were applied respectively before division surgery. The constriction effect, reliability, reproducibility, and the patients' pain tolerance were compared.

RESULTS

 A total of 20 forehead flaps were included. The cable tie had less incidence of loosening (7.7% vs. 16.6%, p < 0.05) and maintained the pressure more effectively. The pain score for the nylon cable tie was significantly lower than the clamped rubber band (4.25 ± 1.02 vs. 6.75 ± 1.12, p < 0.05), especially for 10 pediatric patients (4.50 ± 0.85 vs. 8.10 ± 1.20, p < 0.01). All 20 pedicles were successfully divided at 19 to 22 days with no surgical complications.

CONCLUSION

 Compared with the clamped rubber band, the cable tie produces a more reliable and reproducible ischemic preconditioning effect. It is also better tolerated by the patients. Therefore, we recommend using the nylon cable tie as the preferred device for ischemic preconditioning of the forehead flap.

Augmented Reality to Assist Skin Paddle Harvesting in Osteomyocutaneous Fibular Flap Reconstructive Surgery: A Pilot Evaluation on a 3D-Printed Leg Phantom

Background

Augmented Reality (AR) represents an evolution of navigation-assisted surgery, providing surgeons with a virtual aid contextually merged with the real surgical field. We recently reported a case series of AR-assisted fibular flap harvesting for mandibular reconstruction. However, the registration accuracy between the real and the virtual content needs to be systematically evaluated before widely promoting this tool in clinical practice. In this paper, after description of the AR based protocol implemented for both tablet and HoloLens 2 smart glasses, we evaluated in a first test session the achievable registration accuracy with the two display solutions, and in a second test session the success rate in executing the AR-guided skin paddle incision task on a 3D printed leg phantom.

Methods

From a real computed tomography dataset, 3D virtual models of a human leg, including fibula, arteries and skin with planned paddle profile for harvesting, were obtained. All virtual models were imported into Unity software to develop a marker-less AR application suitable to be used both via tablet and via HoloLens 2 headset. The registration accuracy for both solutions was verified on a 3D printed leg phantom obtained from the virtual models, by repeatedly applying the tracking function and computing pose deviations between the AR-projected virtual skin paddle profile and the real one transferred to the phantom via a CAD/CAM cutting guide. The success rate in completing the AR-guided task of skin paddle harvesting was evaluated using CAD/CAM templates positioned on the phantom model surface.

Results

On average, the marker-less AR protocol showed comparable registration errors (ranging within 1-5 mm) for tablet-based and HoloLens-based solution. Registration accuracy seems to be quite sensitive to ambient light conditions. We found a good success rate in completing the AR-guided task within an error margin of 4 mm (97% and 100% for tablet and HoloLens, respectively). All subjects reported greater usability and ergonomics for HoloLens 2 solution.

Conclusions

Results revealed that the proposed marker-less AR based protocol may guarantee a registration error within 1-5 mm for assisting skin paddle harvesting in the clinical setting. Optimal lightening conditions and further improvement of marker-less tracking technologies have the potential to increase the efficiency and precision of this AR-assisted reconstructive surgery.

Matching the perforating branch of the internal thoracic artery and the deep inferior epigastric artery for breast reconstruction using multi-detector row computed tomography

PURPOSE

Matching the diameter of the deep inferior epigastric artery (DIEA) and perforating branch (PB) of the internal thoracic artery (ITA) is important for arterial anastomosis during breast reconstruction using the DIEA flap. An anatomic investigation of these arteries was performed using multidetector row computed tomography (MDCT).

PATIENTS AND METHODS

Contrast-enhanced MDCT data of 50 women (aged 18-90 years) covering the neck to the groin were analyzed. The diameter of the PBs of the ITA at their origins from the first to the sixth intercostal space and of the DIEA 20 mm from the bifurcation of the external iliac artery were measured.

RESULTS

The mean diameters of the right and left DIEAs were 1.53 ± 0.263 mm and 1.53 ± 0.306 mm, respectively. The diameter of the PBs in the second and third intercoastal spaces was the same as the diameter of the DIEA, bilaterally.

CONCLUSION

It is suggested that anastomosis of the DIEA with PBs of the ITA in the second and third intercoastal spaces is optimal for DIEA flap grafting. Our results could contribute to making vascular anastomosis easier, thereby reducing the burden on both surgeons and patients.

A single-center retrospective comparison of Duplex ultrasonography versus audible Doppler regarding anterolateral thigh perforator flap harvest and operative times

INTRODUCTION

We reported on the superiority of preoperative Duplex mapping ("Duplex") over audible Dopplers ("Doppler") in anterolateral thigh perforator (ALT) free flaps for upper extremity reconstruction. To corroborate our findings on a larger cohort, we conducted this present study focusing on surgical efficiency and patient safety.

METHODS

150 consecutive ALT free flaps were divided into 65 cases of preoperative Duplex versus 85 Doppler controls. We first compared patient demographics, operative details, and defect and flap characteristics. We then assessed group differences in the number and course of perforators pursued intraoperatively, flap harvest and operative times, and donor-site complications. Additionally, the impact of the training level of the primary microsurgeon was evaluated.

RESULTS

Cases and controls were comparable regarding age (p = .48), sex (p = .81), ASA class (p = .48), and BMI (p = .90). Duplex was associated with an increased likelihood of raising flaps on one single dominant perforator of purely septal course and significant reductions of flap harvest (68 ± 10 min, p < .0001) and operative times (74 ± 16 min, p < .0001), regardless of the experience of the primary microsurgeon. There were strong negative linear correlations between preoperative Duplex and both the flap harvest and operative times (p < .0001). Additionally, while there was no effect on the emergency take-back rate (OR = 1.3, p = .60), revisions were significantly less likely among duplexed patients (OR = 0.15, p = .04).

CONCLUSIONS

Preoperative Duplex is associated with a significant reduction in ALT free flap harvest and overall operative times, as well as donor-site revisions as opposed to Doppler planning, regardless of the training level of the primary microsurgeon.

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.

Surgical Free Flaps and Grafts in Head and Neck Reconstruction: Principles and Postoperative Imaging

This review article discusses the basic principles behind the use of flaps and grafts for reconstructive surgery in the head and neck, with a special emphasis on the types of commonly used free flaps, their imaging appearance as well as some frequently encountered postoperative complications. Given the ubiquity and complexity of these reconstructive techniques, it is essential that head and neck radiologists be familiar in distinguishing between the expected evolving findings, complications, and tumor recurrence.

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.

[Indocyanine green angiography technique assisted brachial artery perforator propeller flap to repair soft tissue defects of trunk and upper limb]

OBJECTIVE

To explore the feasibility of using indocyanine green (ICG) angiography to detect brachial artery perforators, and the clinical application of brachial artery perforator propeller (BAPP) flaps to repair soft tissue defects of the trunk and upper limbs.

METHODS

Between August 2016 and February 2019, ICG angiography was used to detect the perforating vessels of the brachial artery muscle septum, and the BAPP flaps were cut out with the detected perforating vessels as the pedicle to repair 19 cases of trunk and upper limb soft tissue defects. There were 12 males and 7 females, with an average age of 28.6 years (range, 5-66 years). Etiologies included the post-burn scar in 10 cases, soft-tissue sarcoma in 5 cases, congenital melanocytic nevi in 2 cases, chronic chest wall ulcer in 1 case, and malignant melanoma in 1 case. Defects located in axilla in 8 cases, chest wall in 4 cases, elbow in 5 cases, and shoulder in 2 cases. The area of the defect ranged from 15 cm×3 cm to 20 cm×8 cm. Pre-transfer tissue expansion was used in 11 patients. Thirteen flaps were pedicled with 1 perforator vessel, and 6 flaps were pedicled with 2 perforator vessels. The length of the vascular pedicle was 2.5-4.5 cm, with an average of 3.08 cm. The area of the skin flap ranged from 11 cm×5 cm to 22 cm×10 cm. The flap rotation angle was 110° in 1 case, 120° in 1 case, and 180° in 17 cases. Except for one donor site repaired by skin graft, the other donor sites were directly sutured.

RESULTS

A total of 24 perforating vessels of the brachial artery muscle septum were detected by ICG angiography, 26 were identified during the operation, with an accuracy rate of 92.31%. Eighteen flaps survived without arteriovenous crisis. Venous congestion was observed in the distal 3-cm of one flap and the flap survived after conservative management. Intraoperative analysis showed that the blood perfusion of the distal 4-cm of one flap was poor, the relative value was less than 32%, the flap survived after removing the poor perfusion area. All the patients were followed up 3 to 23 months (mean, 8.6 months). The color and texture of the flap were similar to those of the recipient area. Flap debulking was not needed in all patients owing to the thinness of the flap. The contracture symptoms of patients with scar contracture on the medial of the elbow joint and axilla were significantly improved; a patient with malignant melanoma underwent tumor resection at 1 year and 5 months after operation due to tumor recurrence, and additional surgery was done to remove the recurrent tumor. No tumor recurrence was found in other patients.

CONCLUSION

The ICG angiography technique can be used to explore the perforating vessels of the brachial artery muscle septum. The BAPP flap pedicled with the perforating vessels can be used for the repair of skin and soft tissue defects in the chest wall, axilla, shoulder, and elbow joint.

Infrared thermography-guided designing and harvesting of pre-expanded pedicled flap for head and neck reconstruction

BACKGROUND

Pre-expanded pedicled flaps possess a more flexible transfer pattern and higher tissue utilization than random flaps, but the perfusion is fully dependent on the chosen axial vessels. A precise mapping of the vessels would assist the surgical design and increase the likelihood of success. The application of Infrared thermography (IRT) has been previously reported for perforator location. The aim of this study is to report the use of IRT in mapping the course and distribution of axial vessels in the pre-expanded flap to guide the designing and harvesting.

METHODS

Patients who underwent head and neck reconstruction using pre-expanded flaps were included. After tissue expansion, IRT was used to mark the vessel distribution along the expanded flap. The results were compared with color Doppler ultrasound (CDU) and/or computed tomographic angiography (CTA). The flap was designed and raised based on the pre-operative marking by IRT. The mark was verified intraoperatively.

RESULTS

A total of 26 expanded flaps were performed, including 20 pedicled flaps and 6 free flaps. IRT succeeded to map the vessel distribution in all cases. All marked results were verified by CDU, CTA, and intraoperative dissection (26/26, 100%). IRT showed more comprehensive distribution of vascular branches than CDU or CTA, and could be utilized intraoperatively to identify the arteries.

CONCLUSION

IRT provides accurate and comprehensive mapping of the axial vessel distribution in the pre-expanded flaps, assisting with flap design and harvest. It is easy to use and non-invasive as an important tool pre- or intraoperatively to ensure the safe elevation.

Duplex echography as an adjuvant tool to clinical examination to detect early postoperative free flap vascular compromise

BACKGROUND

Clinical examination remains the cornerstone for postoperative monitoring of free flaps but is highly dependent on the surgeon's ability and experience. Duplex echography provides a noninvasive objective evaluation of tissue perfusion. The authors hypothesized that duplex echography may be a more sensitive and specific monitoring method for early detection of postoperative flap compromise compared to clinical examination alone. The goal was to evaluate any differences between combined duplex echography and clinical examination flap monitoring versus isolated clinical evaluation.

METHODS

A total of 730 free flaps in 700 patients were included in the study. We conducted an intra-subject prospective study of a cohort of patients who underwent free flap reconstruction in our unit to compare clinical examination with duplex echography for postoperative monitoring. An inter-subject study was also undertaken comparing the prospective cohort with a historical control group of patients in whom free flap monitoring was made using clinical examination alone. The patency flow and velocities through the artery and vein of the flap were measured at the donor and recipient vessels of every anastomosis by duplex scanning, by the same plastic surgeon every 4 hr, during the first 18 hr after surgery.

RESULTS

Duplex echography and clinical evaluation were used in 175 patients. The historical cohort included a total of 525 flaps. Every patient with suspicion of vascular compromise based on duplex echography was taken back for surgical re-exploration. There were no cases of overdiagnosis using duplex echography (Sensitivity 100%, Specificity 100%). Clinical evaluation detected issues with the vascularan astomoses in 23/175 flaps. However, it failed to detect 12/22 cases which presented with vascular complications and gave a false indication of possible complications in 13 flaps (Sensitivity 45%, Specificity 92%).

CONCLUSION

In our practice, duplex echography is considered a useful adjunct monitoring tool for early detection of postoperative flap compromise, which compliments clinical evaluation. It provides anatomic and hemodynamic information of the vascular status and may therefore increase survival of flaps by allowing earlier detection of vascular compromise, compared to clinical examination alone, in postoperative monitoring of free flaps.