A New and Innovative Method of Preoperatively Planning and Projecting Vascular Anatomy in DIEP Flap Breast Reconstruction: A Randomized Controlled Trial

Projected augmented reality in DIEP flap breast reconstruction: Projecting perforators on the skin using dynamic infrared thermography

BACKGROUND

Dynamic infrared thermography (DIRT) is a quick and non-invasive technique for perforator mapping in free flaps that provides real-time information. After a cold challenge, areas best supplied with blood become visible hotspots on color-coded maps, indicating perforators. This study presents a proof of principle for a new and innovative feature of DIRT, where projected augmented reality is used to directly display thermal images on the patient's abdomen prior to the deep inferior epigastric artery perforator (DIEP) flap breast reconstruction.

METHODS

A self-aligning projection device prototype (Anatomy Projector) equipped with an integrated thermal camera was used to obtain thermal information and project the color-coded map directly on the patient's abdomen before DIEP flap breast reconstruction. Projected DIRT hotspots were verified using a hand-held Doppler, and compared to the vascularity on computed tomography angiography (CTA), and intraoperative perforator measurements following a Cartesian grid.

RESULTS

A total of 514 DIRT hotspots were projected in 50 patients, among them 97.3% could be verified using Doppler. The positive predictive value for CTA was 74.5%. Intraoperative measurements yielded 132 perforators in 71 flaps, among them 75 perforators (56.8%) correlated with projected DIRT hotspots, and half of them (54.7%) appeared within the first 5 emerging hotspots.

CONCLUSION

This study showed that real-time display of thermal data in DIEP flap breast reconstruction is feasible via projected augmented reality. Projection facilitates convenient marking of hotspots, and a high resemblance to Doppler and CTA data was observed. Further research should assess the added value of projecting thermal images intraoperatively and in other fields of plastic surgery.

Alternatives to the Gold Standard: A Systematic Review of Profunda Artery Perforator and Lumbar Artery Perforator Flaps for Breast Reconstruction

INTRODUCTION

Breast reconstruction with the deep inferior epigastric perforator (DIEP) flap is the current gold-standard autologous option. The profunda artery perforator (PAP) and lumbar artery perforator (LAP) flaps have more recently been described as alternatives for patients who are not candidates for a DIEP flap. The aim of this study was to review the survival and complication rates of PAP and LAP flaps, using the DIEP flap as a benchmark.

METHODS

A literature search was conducted using PubMed, MEDLINE, Embase, BIOSIS, Web of Science, and Cochrane databases. Papers were screened by title and abstract, and full texts reviewed by three independent blinded reviewers. Quality was assessed using MINORS criteria.

RESULTS

Sixty-three studies were included, for a total of 745 PAP, 62 stacked PAP, 187 LAP, and 23,748 DIEP flap breast reconstructions. The PAP (98.3%) had comparable success rate to DIEP (98.4%), and the stacked PAP (88.7%) and LAP (92.5%) success rate was significantly lower (P < 0.0001). The PAP and LAP groups both had a low incidence of fat necrosis. However, the revision rate for the LAP group was 16.1% whereas the PAP group was 3.3%. Donor site wound dehiscence rate was 2.9 in the LAP group and 9.1% in the PAP group.

CONCLUSIONS

Profunda artery perforator and DIEP flaps demonstrate very high rates of overall survival. The LAP flap has a lower survival rate. This review highlights the survival and complication rates of these alternative flaps, which may help clinicians in guiding autologous reconstruction technique when a DIEP flap is unavailable.

A systematic review of randomised controlled trials in breast reconstruction

BACKGROUND

For preference sensitive treatments, such as breast reconstructions, there are barriers to conducting randomised controlled trials (RCTs). The primary aims of this systematic review were to investigate what type of research questions are explored by RCTs in breast reconstruction, where have they been performed and where have they been published, and to thematise the research questions and thus create an overview of the state of the research field.

METHODS

Randomised controlled trials investigating any aspect of breast reconstructions were included. The PubMed database was searched with a pre-defined search string. Inclusion and data abstraction was performed in a pre-defined standardised fashion. For the purpose of this study, we defined key issues as comparison of categories of breast reconstruction and comparison of immediate and delayed breast reconstruction, when the thematisation was done.

RESULTS

A total of 419 abstracts were retrieved from the search. Of the 419, 310 were excluded as they were not RCTs concerning some aspect of breast reconstruction, which left us with 110 abstracts to be included in the study. The research questions of the included studies could more or less be divided into seven different themes inclusive of 2 key issues: Other issues - comparison of different categories of breast reconstruction, comparison of immediate and delayed breast reconstruction, surgical details within a category of breast reconstruction, surgical details valid for several categories of breast reconstruction, donor site management, anaesthetics, and non-surgical details. Only five studies compared key issues, and they all illustrate the challenges with RCTs in breast reconstruction.

CONCLUSIONS

A total of 110 publications based on RCTs in breast reconstruction have been published. Seven themes of research questions could be identified. Only five studies have explored the key issues. Better scientific evidence is needed for the key issues in breast reconstruction, for example by implementing a new study design in the field.

Skin deformation analysis for pre-operative planning of DIEAP flap reconstruction surgery

Deep inferior epigastric artery perforator (DIEAP) flap reconstruction surgeries can potentially benefit from augmented reality (AR) in the context of surgery planning and outcomes improvement. Although three-dimensional (3D) models help visualize and map the perforators, the anchorage of the models to the patient's body during surgery does not consider eventual skin deformation from the moment of computed tomography angiography (CTA) data acquisition until the position of the patient while in surgery. In this work, we compared the 3D deformation registration from supine arms down (CTA position) to supine with arms at 90° degrees (surgical position), estimating the patient's skin deformation. We processed the data sets of 20 volunteers with a 3D rigid registration tool and performed a descriptive statistical analysis and statistical inference. With 2.45 mm of root mean square and 2.89 mm of standard deviation, results include 30% cases of deformation above 3 mm and 15% above 4 mm. Pose transformation deformation indicates that 3D surface data from the CTA scan position differs from data acquired in loco at the surgical table. Such results indicate that research should be conducted to construct accurate 3D models using CTA data to display on the patient, while considering projection errors when using AR technology.

Evaluation of the impact of technical physicians on improving individual patient care with technology

BACKGROUND

The rapid introduction of technical innovations in healthcare requires that professionals are adequately prepared for correct clinical use of medical technology. In response to the technological transformation of healthcare, a new type of professional, the Technical Physician (TP), was created and is trained to improve individual patient care using technology tailored to the needs of individual patients. This study investigates the TPs' impact on patient care in terms of innovation, effectiveness, efficiency, and patient safety.

METHOD

Semi-structured, in-depth interviews were conducted with 30 TPs and 17 medical specialists (MSs) working in academic or teaching hospitals in the Netherlands. The pre-structured and open-ended interview questions focused on: 1) the perceived impact on innovation, effectiveness, efficiency, and safety, and 2) opportunities and challenges in daily work.

RESULTS

TPs and MSs unanimously experienced that TPs contributed to innovation. A majority indicated that effectiveness (TP 57%; MS 71%) and efficiency (TP 67%; MS 65%) of clinical practice had increased. For safety, 87% of TPs but only 47% of MSs reported an increase. The main explanation given for TPs positive impact was combining medical and technical knowledge. Mainly organizational barriers were mentioned as a potential cause for a less visible contribution of TPs.

CONCLUSION AND DISCUSSION

TPs and MSs unanimously agreed that TPs contributed to innovating patient care through their integrative medical and technical competencies. Most TPs and MSs also reported increased effectiveness, efficiency, and safety of patient care due to the TPs' work. TPs and MSs expected that the TPs' impact on direct and indirect patient care will be enhanced once organizational barriers are removed.

Augmented reality-assisted systematic mapping of anterolateral thigh perforators

PURPOSE

In soft tissue reconstructive surgery, perforator localization and flap harvesting have always been critical challenges, but augmented reality (AR) has become a dominant technology to help map perforators.

METHODS

The lateral circumflex femoral artery (LCFA) and its perforators were reconstructed by CTA in consecutive patients (N = 14). Then, the anterolateral thigh perforators and the points from which the perforators emerged from the deep fascia were marked and projected onto the skin surface. As the virtual images were projected onto patients according to bony markers, the courses of the LCFA and its perforators were depicted on the skin surface for intraoperative guidance. Finally, the locations of the emergence points were verified by intraoperative findings and compared to those determined by handheld Doppler ultrasound.

RESULTS

The sources, locations, and numbers of perforators were determined by CTA. The perforators and their emergence points were accurately mapped on the skin surface by a portable projector to harvest the anterolateral thigh perforator flap. During the operation, the accuracy of the CTA & AR method was 90.2% (37/41), and the sensitivity reached 97.4% (37/38), which were much higher than the corresponding values of Doppler ultrasound. Additionally, the differences between the AR-marked points and the intraoperative findings were much smaller than those seen with Doppler ultrasound (P < 0.001). Consequently, all of the flaps were well designed and survived, and only one complication occurred.

CONCLUSION

Augmented reality, namely, CTA combined with projection in this study, plays a vital and reliable role in locating the perforator emergence points and guiding the procedure to harvest flaps and has fewer potential risks.

ACR Appropriateness Criteria® Imaging of Deep Inferior Epigastric Arteries for Surgical Planning (Breast Reconstruction Surgery): 2022 Update

Breast cancer is the most common malignancy in women in the United States, with surgical options including lumpectomy and mastectomy followed by breast reconstruction. Deep inferior epigastric perforator (DIEP) flap is a muscle-sparing perforator free flap breast reconstruction technique, which uses the deep inferior epigastric artery (DIEA) perforators to create a vascular pedicle. Multiple perforators are identified by preoperative imaging, which are typically ranked based on size, location, and intramuscular course. The goal of preoperative imaging is to aid the surgical team in preoperative planning given the variability of the DIEA perforator branches anatomy between patients. The objective of this document is to review the imaging modalities that can be used preoperatively to identify the optimal perforator and thereby reduce intraoperative complications, reduce postoperative complications, and improve clinical outcomes. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

FlapMap Visual Language System for Vascular Imaging Prior to Microvascular Free Tissue Transfer

Preoperative vascular imaging has been shown to be beneficial before free tissue transfer procedures, especially for deep inferior epigastric perforator flap breast reconstruction. Although computerized tomography angiography and magnetic resonance angiogram are increasingly frequently performed, there is no standardized method for recording, analyzing, and communicating the vast amount of clinically relevant information that is obtained from these tomographic imaging studies. Herein, the authors propose a new visual language system for preoperative imaging called “FlapMap,” which allows for the creation of a clinically actionable, easily understood, and easily communicated single image that aids in preoperative planning before microvascular free tissue transfer.

Advances in perforator imaging through holographic CTA and augmented reality: a systematic review

Introduction: Free tissue transfer has become a mainstay in reconstructive plastic surgery, and techniques to plan such surgery continue to evolve. Novel technologies and increases in computational power have enabled computed tomographic angiography (CTA)data augmentation onto patients to assist in pedicle identification and dissection. Given the rapidly evolving field and research in this domain, a systematic re-view was undertaken to establish the evidence for its usefulness in pedicle identification and dissection. Methods: An extensive search using keywords in EMBASE and PubMed with bibliographic linkage following PRISMA guidelines was performed. 107 articles were identified. Duplicate articles were removed prior to review. Two reviewers independently screened the titles for appropriate topic relevance. Full articles were then screened for review. Results: Eleven articles were appropriate for review. Two articles analysed the time taken to identify perfo-rators using augmented reality (AR) compared to Doppler ultrasound. The remainder of the articles ana-lysed time to perforator identification, differences between projected location and dissected perforator location, qualitative feedback from surgeons on the use of AR systems for perforator identification and proof of concept and the usefulness of AR in perforator flap surgery. Conclusion: This review demonstrates that while established methods of data rendering and projection can achieve holographic projection and AR, there is a lack of objective outcome data to demonstrate its usefulness. This, combined with a cost analysis, are the main obstructions to this technology being more widely adopted.

Current Applications of Ultrasound Imaging in the Preoperative Planning of DIEP Flaps

Background The deep inferior epigastric artery perforator (DIEP) flap has become the gold standard for autologous breast reconstruction at many institutions. Although the deep inferior epigastric artery displays significant anatomic variability in its intramuscular course, branching pattern and location of perforating vessels, the ability to preoperatively visualize and map relevant vascular anatomy has increased the efficiency, safety and reliability of the DIEP flap. While computed tomography angiography (CTA) is often cited as the preoperative imaging modality of choice for perforator flaps, more recent advances in ultrasound technology have made it an increasingly attractive alternative.

Methods An extensive literature review was performed to identify the most common applications of ultrasound technology in the preoperative planning of DIEP flaps.

Results This review demonstrated that multiple potential uses for ultrasound technology in DIEP flap reconstruction including preoperative perforator mapping, evaluation of the superficial inferior epigastric system and as a potential adjunct in flap delay procedures. Available studies suggest that ultrasound compares favorably to other widely-used imaging modalities for these indications.

Conclusion This article presents an in-depth review of the current applications of ultrasound in the preoperative planning of DIEP flaps and explores some potential areas for future investigation.

Necrosis or Flap Loss After Deep Inferior Epigastric Perforator Reconstruction: Impact of Perforators and Recipient Vessels

Background The aim of this study is to analyze the impact of the number and location of perforators harvested and the recipient vessels used on deep inferior epigastric perforator (DIEP) flap survival and the occurrence of flap necrosis requiring re-operation.

Patients and Methods Four hundred and seventy-one DIEP flap reconstructions, performed between January 2008 and December 2019, were retrospectively analyzed.

Results Flap necrosis requiring re-operation was observed in 40 (9%) of flaps and total flap loss rate was 1% (n = 6). No significant differences were observed between internal mammary vessels (IMV, n = 287, 61%) and thoracodorsal vessels (TDV, n = 184, 39%) regarding postoperative re-anastomosis (p = 0.529) or flap survival (p = 0.646). Intraoperative conversion from IMV to TDV was performed on 64 (14%) patients. TDV were more commonly associated with problems in preparation of the vessels than IMV (p < 0.001). Second vein anastomosis was performed on 18 (4%) patients. In total, 81 flaps (17%) had one perforator, 165 (35%) had two, 218 (46%) had three to five, and 7 (2%) had more than five perforators. Flaps with three to five perforators were more commonly associated with flap necrosis (p < 0.001) than flaps with one or two perforators. Independent factors associated with necrosis were body mass index (BMI) > 30 (odds ratio [OR]: 2.28; 95% confidence interval: 1.06–4.91, p = 0.035) and perforator/s located on the lateral row (OR: 3.08, 95% CI 1.29–7.33, p = 0.011).

Conclusion We conclude that the occurrence of flap necrosis requiring re-operation may be higher in DIEP flaps with more than two perforators or perforator/s located on the lateral row and in obese patients. Neither the recipient vessels used nor the number of perforators harvested had any impact on the flap survival rate.

Holographic Augmented Reality for DIEP Flap Harvest

BACKGROUND

During a deep inferior epigastric perforator (DIEP) flap harvest, the identification and localization of the epigastric arteries and its perforators are crucial. Holographic augmented reality is an innovative technique that can be used to visualize this patient-specific anatomy extracted from a computed tomographic scan directly on the patient. This study describes an innovative workflow to achieve this.

METHODS

A software application for the Microsoft HoloLens was developed to visualize the anatomy as a hologram. By using abdominal nevi as natural landmarks, the anatomy hologram is registered to the patient. To ensure that the anatomy hologram remains correctly positioned when the patient or the user moves, real-time patient tracking is obtained with a quick response marker attached to the patient.

RESULTS

Holographic augmented reality can be used to visualize the epigastric arteries and its perforators in preparation for a deep inferior epigastric perforator flap harvest.

CONCLUSIONS

Potentially, this workflow can be used visualize the vessels intraoperatively. Furthermore, this workflow is intuitive to use and could be applied for other flaps or other types of surgery.

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.

Virtual and augmented reality for preoperative planning in plastic surgical procedures: A systematic review

BACKGROUND

Virtual and augmented reality (VR and AR) are fast-developing technologies that allow the three-dimensional visualization of digital information.

OBJECTIVE

This systematic review aimed to compare the application of VR and AR to conventional methods in preoperative planning of plastic surgical procedures.

METHOD

A systematic literature search was conducted in Embase, Medline (Ovid), Web-of-Science, Cochrane, and Google Scholar databases on October 11, 2019. All literature comparing AR and/or VR with conventional methods for preoperative planning was collected. Only articles that studied at least one of the following outcomes were included: technical accuracy of the procedure, operative time, complications, and costs of total intervention.

RESULTS

No articles on VR were found. Six articles were found on interventions performed with AR assistance. AR showed to be significantly better for the accuracy of osteotomies in mandibular angle osteotomies and intraoral mandible distraction compared to conventional methods. For synostotic plagiocephaly and orbital hypertelorism correction, the use of AR demonstrated a precise osteotomy. Intraoperative perforator identification in DIEP flap procedures was more accurate with AR compared to Doppler ultrasound. Harvesting time (p < 0.012) and operative time (p < 0.01) in DIEP-flap procedures and mandibular angle osteotomies, respectively, were significantly reduced if AR was used. No articles were found regarding the costs of using AR for preoperative planning.

CONCLUSION

AR technology has the potential to assist the plastic surgeon in operating more accurately, safely, and fast. Studies on VR technology for preoperative planning in plastic surgery are lacking. More comparative studies are necessary, including data on clinical outcomes and cost-effectiveness.