Indocyanine green angiography and the old question of vascular autonomy – Long term changes of microcirculation in microsurgically transplanted free flaps

Engineering exosomes from fibroblast growth factor 1 pre-conditioned adipose-derived stem cells promote ischemic skin flaps survival by activating autophagy

Background

The recovery of ischemic skin flaps is a major concern in clinical settings. The purpose of this study is to evaluate the effects of engineered exosomes derived from FGF1 pre-conditioned adipose-derived stem cells (FEXO) on ischemic skin flaps.

Method

6 patients who suffered from pressure ulcer at stage 4 and underwent skin flaps surgery were recruited in this study to screen the potential targets of ischemic skin flaps in FGF family. FGF1 was co-incubated with adipose stem cells, and ultracentrifugation was applied to extract FEXO. Transcriptome sequencing analysis was used to determine the most effective microRNA in FEXO. Animal skin flaps models were established in our study to verify the effects of FEXO. Immunofluorescence (IF), western blotting (WB) and other molecular strategy were used to evaluate the effects and mechanism of FEXO.

Results

FGF1 was expected to be the therapeutic and diagnostic target of ischemic skin flaps, but there is still some deficiency in rescuing skin flaps. FEXO significantly improved the viability of RPSFs and endothelial cells by inhibiting oxidative stress and alleviating apoptosis and pyroptosis through augmenting autophagy flux. In addition, FEXO inhibited the over-activated inflammation responses. Transcriptome sequencing analysis showed that miR-183-5p was significantly elevated in FEXO, and inhibiting miR-183-5p resulted in impaired protective effects of autophagy in skin flaps. The exosomal miR-183-5p markedly enhanced cell viability, inhibited oxidative stress and alleviated apoptosis and pyroptosis in endothelial cells by targeting GPR137 through Pi3k/Akt/mTOR pathway, indicating that GPR137 could also be a therapeutic target of ischemic skin flap. It was also notabale that FGF1 increased the number of exosomes by upregulating VAMP3, which may be a promising strategy for clinical translation.

Conclusion

FEXO markedly improved the survivial rate of ischemic skin flaps through miR-183-5p/GPR137/Pi3k/Akt/mTOR axis, which would be a promising strategy to rescue ischemic skin flaps.

[Revascularization Prior to Defect Reconstruction of the Lower Limb - Essential Cooperation between Plastic and Vascular Surgery]

Treatment of complex ischemic lower leg defects with exposure of deep anatomic structures represents a considerable challenge to involved specialties. In selected patients, limb salvage can be achieved as an alternative to major amputation by means of a combined approach including arterial reconstruction and subsequent free flap transfer. Arterial reconstruction can be performed either by endovascular or open surgical treatment (bypass reconstruction or implantation of an arteriovenous loop) preliminary to defect reconstruction using microsurgical free flap transplantation. Whereas the aim of the arterial reconstruction comprises the establishment of sufficient perfusion and creation of adequate target vessels for the free flap transfer, the selection of the appropriate flap entity depends on the extent of the wound as wells as on the presence of osteomyelitis. Arterial reconstruction and defect reconstruction can be performed as one-stage or two-stage procedure and has become an established and feasible treatment approach in centers. Evaluation of microperfusion by means of indocyanine green can further increase safety and feasibility of this method. Against this background, combined arterial reconstruction and subsequent free flap transfer provides excellent results in terms of amputation free survival and postoperative mobility. Essential is however an individualized decision making in consideration of patient selection and possible contraindications. This approach may be evaluated in mobile patients with complex wounds prior to major amputation.

Detection of wound healing disorders after major amputations by measurements of the microcirculation: A prospective single-center study

Introduction

Although major amputations can often be avoided due to evolving methods of endovascular and surgical revascularizations techniques, in patients with chronic limb-threatening ischemia, it is still necessary in some cases. Aim of this study was the detection of wound healing disorders through intraoperative microcirculation measurements in major limb amputations.

Materials and methods

In this single-center clinical study, patients with an indication for major amputation were enrolled prospectively. Cause of amputation, patients' comorbidities including cardiovascular risk profile were assessed. Macrocirculation, as well as microcirculation were assessed. Microcirculation measurements were performed by fluorescence angiography with the administration of indocyanine green. A preoperative measurement was obtained at the amputation level, followed by three additional measurements of the amputation stump postoperatively. Wound healing was monitored and correlated with the microcirculatory findings, based on the perfusion parameters ingress and ingress rate, calculated in the indocyanine green fluorescence video sequences of the amputation stumps.

Results

Forty-five patients were enrolled, including 19 (42%) below-the-knee amputations and 26 (58%) above-the-knee amputations. When considering the need for revision, a change in the microperfusion parameters was observed postoperatively. The mean value for ingress was significantly lower directly postoperatively in stumps requiring revisions (5 ± 0 A.U. versus 40.5 ± 42.5 A.U., p < 0.001). The mean value of ingress rate behaved similarly (0.15 ± 0.07 A.U./s versus 2.8 ± 5.0 A.U./s, p = 0.005). The evaluation of indocyanine green measurements when wound healing disorders occurred also showed nonsignificant differences in the mean values.

Conclusion

Fluorescence angiography after major lower limb amputations appears to be an option of depicting microperfusion. Especially, the early postoperative detection of reduced perfusion can indicate a subsequent need for revision. Therefore, this method could possibly serve as a tool for intraoperative quality control after major limb amputation.

An overview of current assessment techniques for evaluating cutaneous perfusion in reconstructive surgery

This article provides a comprehensive analysis of modern techniques used in the assessment of cutaneous flaps in reconstructive surgery. It emphasizes the importance of preoperative planning and intra- and perioperative assessment of flap perfusion to ensure successful outcomes. Despite technological advancements, direct clinical assessment remains the gold standard. We categorized assessment techniques into non-invasive and invasive modalities, discussing their strengths and weaknesses. Non-invasive methods, such as acoustic Doppler sonography, near-infrared spectroscopy, hyperspectral imaging thermal imaging, and remote-photoplethysmography, offer accessibility and safety but may sacrifice specificity. Invasive techniques, including contrast-enhanced ultrasound, computed tomography angiography, near-infrared fluorescence angiography with indocyanine green, and implantable Doppler probe, provide high accuracy but introduce additional risks. We emphasize the need for a tailored decision-making process based on specific clinical scenarios, patient characteristics, procedural requirements, and surgeon expertise. It also discusses potential future advancements in flap assessment, including the integration of artificial intelligence and emerging technologies.

The Autonomization Principle in Vascularized Flaps: An Alternative Strategy for Composite Tissue Scaffold In Vivo Revascularization

Autonomization is a physiological process allowing a flap to develop neo-vascularization from the reconstructed wound bed. This phenomenon has been used since the early application of flap surgeries but still remains poorly understood. Reconstructive strategies have greatly evolved since, and fasciocutaneous flaps have progressively replaced muscle-based reconstructions, ensuring better functional outcomes with great reliability. However, plastic surgeons still encounter challenges in complex cases where conventional flap reconstruction reaches its limitations. Furthermore, emerging bioengineering applications, such as decellularized scaffolds allowing a complex extracellular matrix to be repopulated with autologous cells, also face the complexity of revascularization. The objective of this article is to gather evidence of autonomization phenomena. A systematic review of flap autonomization is then performed to document the minimum delay allowing this process. Finally, past and potential applications in bio- and tissue-engineering approaches are discussed, highlighting the potential for in vivo revascularization of acellular scaffolds.

A Personalized Approach to Treat Advanced Stage Severely Contracted Joints in Dupuytren’s Disease with a Unique Skeletal Distraction Device—Utilizing Modern Imaging Tools to Enhance Safety for the Patient

Background: While surgical therapy for Dupuytren’s disease is a well-established standard procedure, severe joint flexion deformities in advanced Dupuytren’s disease remain challenging to treat. Skeletal distraction has proven to be an additional treatment option. Methods: We analyzed the surgical treatment algorithm, including the application of a skeletal distraction device, in patients with a flexion deformity due to Dupuytren’s disease, Iselin stage III or IV, who were operated on from 2003 to 2020 in our department. Results: From a total of 724 patients, we included the outcome of 55 patients’ fingers in this study, who had undergone additional skeletal joint distraction with our Erlangen device. Additional fasciotomy or fasciectomy, in a one- or two-staged procedure, was performed in all patients, according to the individual findings and necessities. The range of motion of the PIP joint improved from 12° to 53°. A number of complications, in all steps of the treatment, were noted in a total of 36.4% of patients, including the development of fractures (16.4%), followed by vessel injury, pin infections, and complex regional pain syndrome (5%). Conclusions: Additional skeletal distraction improves the range of motion of severely contracted joints in Dupuytren’s disease. Nevertheless, careful patient selection is necessary, due to the moderate rate of complications.

Fibula Free Flap Reconstruction of the Maxilla Leading to Extracapsular Ankylosis of the Mandible

After en bloc resection of the maxilla or mandible, surgeons may choose to replace the missing bone and soft tissue with a fibula free flap (FFF). One of the complications that may arise during the healing of an FFF is heterotopic ossification along the free flap pedicle. Heterotopic ossification is most often noted incidentally on postoperative radiographs and rarely creates a functional deficit. Subperiosteal dissection of the pedicle from the bone during the harvest of the FFF is believed to be the main contributing factor that leads to this formation of bone along the flap soft tissue. Pain or limitation of movement of the jaws, depending on where heterotopic bone forms are related functional issues. Changes in facial appearance due to expansion related to this phenomenon of bone deposition may also occur. This paper presents a patient that developed a functional deficit secondary to heterotopic ossification of an FFF that required surgical intervention. The goal of our surgery is to maintain the blood supply to a vascularized flap while removing the heterotopic bone. We will present the unique aspects of planning this challenging surgery: CASE: A 40-year-old man with a history of right posterior maxillary ameloblastoma underwent a hemi-maxillectomy with FFF reconstruction. The patient developed extracapsular heterotopic bone ankylosis beginning 2 months postoperatively developing severe trismus and required surgical intervention. Radiographic imaging revealed extensive heterotopic ossification of the vascular pedicle that extended from the most proximal positioned end of the fibula to the inferior lateral border of the mandible. A radiographic computed tomography with contrast imaging revealed an intact vascular pedicle with surrounding heterotopic bone. Virtual planning and stereolithic modeling were utilized to plan the heterotopic bone removal. In the operating room, we removed the heterotopic bone in small segments according to the virtual plan to avoid injuring the vascular pedicle. A coronoidectomy was also performed to help gain more range of motion. An adipofascial flap using the buccal fat pad was raised into the area of defect to prevent future recurrence. The patient was put on a strict physical therapy regimen to help regain his range of motion. CONCLUSION: Heterotopic ossifications along free flap pedicles are a known complication of the FFF. A conservative management approach should be used since most postoperative patients will be asymptomatic and findings are incidental on postoperative imaging. Surgery should be reserved for symptomatic patients. Heterotopic ossification needs to be considered as a differential in a microvascular reconstruction postoperative patient when the patient presents with a slow onset of facial swelling, neck mass, or trismus. Virtual planning is an essential tool in the surgeon's planning armamentarium dependent on the timing of the procedure so that the vascular integrity of the flap can be protected after the initial anastomosis.

Monitoring free flaps and replanted digits via perfusion index -A proof of concept study

BACKGROUND

Early detection and treatment of vascular complications in replanted digits is essential for the survival. The perfusion index (PI) represents a marker of peripheral perfusion as it shows the ratio of pulsatile to non-pulsatile blood flow.

OBJECTIVE

To evaluate the feasibility and applicability of the PI as a monitoring tool for free flaps and replanted digits by measuring the inter- and intraindividual changes in PI.

METHODS

Five patients were postoperatively monitored according to intern standards by hourly clinical evaluation. Additionally, a pulse oximeter with SET-technology® (Masimo Radial 7, Masimo Corporation, Irvine, USA) was added with a LNCS® Red TFA-1 SpO2 sensor (Masimo Corporation, Irvine, USA) and respectively a LNCS® Neo-3 neonatal finger clip to evaluate the perfusion via PI and SpO2.

RESULTS

All patients showed sufficient perfusion in clinical controls. There was no detectable vascular complication during follow-up. Mean perfusion index was 0.93 with a median of 0.44. The patients showed a mean SpO2 of 90.59%with a median of 89.21%.

CONCLUSION

Our results show a great intra- and interindividual range of PI and SpO2. SpO2 provided an even greater range than PI. Trends in intraindividual PI changes may be a promising monitoring tool for free flaps and replanted digits.

Leaving the perfusion zones? Individualized flap design in 100 free DIEP and ms-TRAM flaps for autologous breast reconstruction using indocyanine green angiography

BACKGROUND

There is still no consensus regarding the ideal zoning in abdominal-based autologous breast reconstruction using free DIEP or ms-TRAM flaps. In particular, the perfusion pattern of the flap according to the number of perforators used and their location remains controversial. In this study, the perfusion of free DIEP and ms-TRAM flaps is assessed intraoperatively and analyzed with regard to different perfusion patterns.

METHODS

A retrospective analysis of 100 free flaps for breast reconstruction was performed. Following complete flap harvest, we used indocyanine green angiography for perfusion analysis. By applying two different contour levels, DIEP flaps with lateral or medial perforators and ms-TRAM flaps were assessed for their respective perfusion patterns.

RESULTS

No statistically significant differences were found in the size of the perfusion area between the different flap types when applying the contour level of 20% (p >0.05). For the contour level of 30%, however, statistically significant differences were found between DIEP flaps with medially or laterally located perforators (p = 0.038). Laterally or medially located perforators in DIEP flaps showed no significant differences in their ability to cross the midline (contour level 20%, p = 0.068; contour level 30%, p = 0.058).

CONCLUSION

Considering the variability of the perfusion of the abdominal wall and the high sensitivity of indocyanine green angiography for their detection, the abdominal zonings play a minor role. By using intraoperative indocyanine green angiography, a precise and patient-specific free flap surgery for autologous breast reconstruction is possible independent of perforator location.

[Reconstruction of oncological defects of the perianal region]

In addition to the progressive development of surgical oncological techniques for malignant tumors of the rectum, anal canal and vulva, reconstructive procedures after oncological interventions in the perianal region represent a cornerstone in the postoperative quality of life of patients. Modern treatment modalities for rectal cancer with neoadjuvant chemoradiotherapy increase the survival rate and simultaneously reduce the risk of local recurrence to 5-10%, especially by cylindrical extralevatory extirpation of the rectum. The price for increased surgical radicality and improved oncological safety is the acceptance of larger tissue defects. Simple suture closure of perineal wounds often does not primarily heal, resulting in wound dehiscence, surgical site infections and formation of chronic fistulas and sinuses. The interdisciplinary one-stage or two-stage reconstruction of the perianal region with well-vascularized tissue has proven to be a reliable procedure to prevent or control such complications.

External Screw-Threaded Traction Device Helps Optimize Finger Joint Mobility in Severe Stage III and IV Dupuytren Disease

Background

Treating advanced finger joint contractures from Dupuytren disease remains a challenge. We evaluated the effectiveness of a skeletal distraction device versus alternative treatment options.

Material/Methods

We analyzed the surgical treatment of contracted finger joints in stage III and stage IV Dupuytren’s disease over a 10-year period. Data were obtained from inpatient and outpatient medical records, including postoperative clinical examinations and extended Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire scores. Complications of infection, postoperative pain, and wound healing disorders were recorded.

Results

A total of 79 patients (83 hands) were assigned to 2 treatment groups. Patients in group 1 underwent an initial open transection of the main fibrous cord, Z-plasty, distraction with the Erlangen external distraction device, and fasciectomy. The distraction period was 13 to 81 days (mean 31 days). Group 2 underwent a conventional single-stage fasciectomy and arthrolysis. DASH scores and subjective patient satisfaction were lower in group 1 (20.7/33%) than in group 2 (10.3/50%). However, the staged approach of group 1 to treat proximal interphalangeal joint contractures in the long term (improvement >40%) was more effective than the approach of group 2 (>33%). Distraction device pin infections occurred in 20% of hands. Postoperative pain and complex regional pain syndrome type I occurred in 25% of hands in group 1 and 3% in group 2.

Conclusions

A screw thread driven external fixation device is useful in end-stage Dupuytren’s finger joint contractures. It is indicated when joint contractures are advanced and simple arthrolysis is insufficient.

Less is more - retrospective comparison of shoulder strength and range of motion between conventional and muscle-sparing harvesting technique of a latissimus dorsi flap

BACKGROUND

The muscle-sparing latissimus dorsi flap poses an alternative to the conventional latissimus dorsi flap when a defect requires a smaller flap volume with a long vascular pedicle. The aim of the study was to analyze the functional outcome following muscle-sparing versus conventional harvest of a latissimus dorsi flap.

MATERIAL AND METHODS

Patients who received a muscle-sparing latissimus dorsi muscle flap transplantation (group 1) and patients with a complete latissimus dorsi muscle flap harvest (group 2) for defect reconstruction at the University Hospital of Erlangen between 2007 and 2016 were examined. The evaluation included a physical examination with the measurement of strength and range of motion of the shoulder of both the donor side as well as the nonoperated side. Furthermore, the DASH score was evaluated. Additionally, patients in group 1 received a neurophysiological examination.

RESULTS

The DASH score did not show statistically significant differences between both groups. Both strength (p = 0.031) and range of motion (p<0.05) of the shoulder of the donor side were statistically significantly lower than the nonoperated side in group 2, while no difference was found in group 1. The neurophysiological examination in group 1 showed a reduced nerve conduction velocity of the donor side as compared to the nonoperated side in most patients (60% and n = 3).

CONCLUSION

Harvesting the muscle-sparing latissimus dorsi flap leads to less functional impairments of the shoulder than harvesting the complete latissimus dorsi flap.

Actually Seeing What Is Going on - Intravital Microscopy in Tissue Engineering

Intravital microscopy (IVM) study approach offers several advantages over in vitro, ex vivo, and 3D models. IVM provides real-time imaging of cellular events, which provides us a comprehensive picture of dynamic processes. Rapid improvement in microscopy techniques has permitted deep tissue imaging at a higher resolution. Advances in fluorescence tagging methods enable tracking of specific cell types. Moreover, IVM can serve as an important tool to study different stages of tissue regeneration processes. Furthermore, the compatibility of different tissue engineered constructs can be analyzed. IVM is also a promising approach to investigate host reactions on implanted biomaterials. IVM can provide instant feedback for improvising tissue engineering strategies. In this review, we aim to provide an overview of the requirements and applications of different IVM approaches. First, we will discuss the history of IVM development, and then we will provide an overview of available optical modalities including the pros and cons. Later, we will summarize different fluorescence labeling methods. In the final section, we will discuss well-established chronic and acute IVM models for different organs.

Retrospective analysis of free temporoparietal fascial flap for defect reconstruction of the hand and the distal upper extremity

INTRODUCTION

Soft tissue reconstruction of the hand and distal upper extremity is challenging to preserve the function of the hand as good as possible. Therefore, a thin flap has been shown to be useful. In this retrospective study, we aimed to show the use of the free temporoparietal fascial flap in soft tissue reconstruction of the hand and distal upper extremity.

METHODS

We analysed the outcome of free temporoparietal fascial flaps that were used between the years 2007and 2016 at our institution. Major and minor complications, defect location and donor site morbidity were the main fields of interest.

RESULTS

14 patients received a free temporoparietal fascial flap for soft tissue reconstruction of the distal upper extremity. Minor complications were noted in three patients and major complications in two patients. Total flap necrosis occurred in one patient.

CONCLUSION

The free temporoparietal fascial flap is a useful tool in reconstructive surgery of the hand and the distal upper extremity with a low donor site morbidity and moderate rates of major and minor complications.

Interdisciplinary Treatment of Breast Cancer After Mastectomy With Autologous Breast Reconstruction Using Abdominal Free Flaps in a University Teaching Hospital-A Standardized and Safe Procedure

Background: Breast cancer is the most common malignancy in women. The interdisciplinary treatment is based on the histological tumor type, the TNM classification, and the patient's wishes. Following tumor resection and (neo-) adjuvant therapy strategies, breast reconstruction represents the final step in the individual interdisciplinary treatment plan. Although manifold flaps have been described, abdominal free flaps, such as the deep inferior epigastric artery perforator (DIEP) or the muscle-sparing transverse rectus abdominis myocutaneous (ms-TRAM) flap, are the current gold standard for autologous breast reconstruction. This retrospective study focuses on the safety of autologous breast reconstruction upon mastectomy using abdominal free flaps. Methods: From April 2012 until December 2018, 193 women received 217 abdominal free flaps for autologous breast reconstruction at the University Hospital of Erlangen. For perforator mapping, we performed computed tomography angiography (CTA). Venous anastomosis was standardized using a ring pin coupler system, and flap perfusion was assessed with fluorescence angiography. A retrospective analysis was performed based on medical records, the surgery report, and follow-up of outpatient course. Results: In most cases, autologous breast reconstruction was performed as a secondary reconstructive procedure after mastectomy and radiotherapy. In total, 132 ms1-TRAM, 23 ms2-TRAM, and 62 DIEP flaps were performed with 21 major complications (10%) during hospital stay including five free flap losses (2.3%). In all cases of free flap loss, we found an arterial thrombosis as the main cause. In 24 patients a bilateral breast reconstruction was performed without free flap loss. The majority of free flaps (96.7%) did not need additional supercharging or turbocharging to improve venous outflow. Median venous coupler size was 2.5 mm (range, 1.5-3.5 mm). Conclusion: Using CTA, intraoperative fluorescence angiography, titanized hernia meshes for rectus sheath reconstruction, and venous coupler systems, autologous breast reconstruction with DIEP or ms-TRAM free flaps is a safe and standardized procedure in high-volume microsurgery centers.

Factors affecting outcomes after supermicrosurgical lymphovenous anastomosis in a defined patient population

BACKGROUND

The optimal surgical treatment for lymphedema is still subject of intensive research. Therefore, it is vital to investigate what significance lymphovenous anastomosis (LVA) has in this context.

OBJECTIVE

This study aims to determine the short- and long-term results as well as the most important factors that can improve outcomes after LVA.

METHODS

This study includes a complete data set of 26 patients who received LVA for a therapy-resistant lymphedema. Patients were followed up for an average of 23 months.

RESULTS

50% of the patients reported a subjective improvement. Without conservative treatment after the operation the patients showed significant better results (100% vs. 40.9%, p = 0.030). The localization of lymphedema as well as the region of LVA had a significant influence. In patients with lymphedema affecting the entire leg, symptom improvement was significantly lower (35.3% vs. 77.8%, p = 0.039). Patients who received LVA in an upper limb show a significantly higher improvement in symptoms than patients who received LVA in a lower limb (100% vs. 30%, p = 0.021).

CONCLUSIONS

We identified factors with a significant influence on the outcome of patients after receiving LVA. Patients with early-stage upper extremity lymphedema seem to benefit most from this procedure.